International Conference & Expo on
Advances in Power
Generation from
Renewable Energy
Sources
(APGRES-2017)
December 22-23, 2017
Government Engineering College Banswara
Behind Mayur Mill, Dungarpur Road Banswara-327001
International Conference & Expo on
Advances in Power
Generation from
Renewable Energy
Sources
(APGRES-2017)
December 22-23, 2017
ISBN-978-81-932091-2-7
GOVERNMENT ENGINEERING COLLEGE BANSWARA
Behind Mayur Mill, Dungarpur Road Banswara-327001
INNOVATIVE RESEARCH PUBLICATION
APGRES-2017 Editorial Board
Mr. Ankur Kulshreshtha, GEC Banswara
Mr. Sohan Lal Swami, GEC Banswara
Mr. Shailendra Goswami, GEC Banswara
Mr. Ravi P. Maheshvari, GEC Banswara
Ms. Shulbha Kothari, GEC Banswara
Mr. Himanshu Swarnkar, GEC Banswara
Dr. Shiv Lal, GEC, Banswara
i
APGRES-2017 Committees
Honored Chair:
Prof. S. C. Kaushik, CES, IIT Delhi, India
Chief Patron:
Honorable Smt. Kiran Maheshwari
Higher and Technical Education Minister, Govt. of Rajasthan
Patron:
Dr. Shiv Lal, Principal, GEC, Banswara
Convener
Dr. N. L. Panwar, CTAE Udaipur
Mr. Gaurav Pathak, GEC Banswara
Coordinators:
Mr. Ankur Kulshreshtha/Mr. Sohan Lal Swami, GEC Banswara
Advisory Committee:
Prof. B. V. Reddy, Univ. of Ontario, Canada
Prof. L.M Das, CES IIT Delhi, India
Prof. S. A. Sherif, Univ. of Florida, U.S.A.
Prof. P. K. Jamwal, Nazarbayev Univ. Astana
Prof. K. S. Ong, Monash University, Malaysia
Prof. M. Maerefat, Tarbiat Modares Univ., Tehran, Iran
Prof. Mohammad O. Hamdan, United Arab Emirates University.UAE
Prof. Atit Koonsrisuk, Suranaree University of Technology, Thailand
Prof. Abdul Khaliq, King Fahd Univ. of Petroleum and minerals, Saudi Arabia
Prof. Richard Petela, Technology Scientific Ltd., Canada
Prof. N. S. Rathor, ADG, ICAR Delhi India
ii
Prof. S. Mishra, UCE RTU Kota, India
Prof. A. K. Pratihar, GPU Uttarakhand, India
Prof. H. Hirani, MED IIT Delhi, India
Prof. Paramjeet Singh, GDEC, PTU, India
Prof. S. L. Soni, MNIT, Jaipur, India
Prof. M.K. Gupta, UEC, Ujjain, India
Prof. Sunil Punjabi, UEC, Ujjain, India
Prof. S. Chandrasekaran, DOE, IIT Chennai
Prof. J. K. Nayak, ESE IIT Bombay
Dr. Henry Tan, Univ. of Aberdeen, Scotland, UK
Dr. P.K. Bhargava, CBRI Roorkee, India
Dr. V Shiva Reddy, SPRERI Anand, India
Dr. Harender, SNU Greater Noida, India
Dr. Navneet Kumar, Galgotia Univ. Gr. Noida, India
Dr. Rajat Bhagwat, MBM, JNVU Jodhpur
Dr. Raj Kumar, YMCA Faridabad, India
Dr. Rahul Dev, MNNIT Allahabad, India
Dr. Akhilesh Arora, DTU Delhi, India
Dr. Amit Sharma, DCRUST, Murthal, India
Dr. Vishal Garg, IIIT Hayderabad, India
Dr. Rohit Mishra, GEC Ajmer, India
Dr. V. Bansal, UCE, RTU Kota, India
Dr. K.N. Patil, SDMCET Dharwad, India
Dr. Ashok Sharma, GASCO Abu Dhabi
Dr. Rahul Rawat, MNRE Delhi India
Mr. Radheshyam Meena, MNRE Delhi India
Dr. M. L. Meena, MNIT Jaipur
Dr. Mukesh Kumar, MNIT Jaipur
Dr. S.K. Singh, SEC, MNRE, India
Dr. Sanjay Kumar, CEL, Sahibabad, U.P. India
Dr. K. Vamsi Krishna, CES IIT Delhi
*******
iii
CONTENTS
i
ii
Editors Board
Committees
S. No.
Title
1.
3-7
6.
Cascade Utilization of Energy and Exergy for the Performance
Analysis of a Solar Powered Cogeneration Cycle
Modeling, simulation and performance analysis of monocrystalline
and polycrystalline panel.
Voltage and frequency controller for three Phase Four Wire Hybrid
System for Loads in Isolation
Effect of Heat Transfer Fluids on the Techno-Economic
Performance of Parabolic Trough based Solar Thermal Power
Generation in India
Determination of optimum heat rejection pressure in transcritical
N2O refrigeration cycle with vortex tube
Impact of Renewable Energy Generation on Bidding Strategy
7.
Review of Different Energy Resources
37-40
8.
IA Review of CFD Methodology used for Solar Devices
41-45
9.
Impact of RES in Distribution Systems
46-48
10.
Microbial pretreated Water hyacinth as an Energy Source
49-55
11.
Effect of Viscosity in Biomechanics for the Fluid: A Review
56-58
12.
13.
Thermodynamic investigation on biomass derived syngas fueled 59-63
combined cycle power plant
Bio Fuel: Need for the sustainable Generation
64-69
14.
Parametric study of Pump as Turbine-1: variation of speed
70-75
15.
Performance Analysis of a Low Price Thermoelectric Cooler: An
Experimental Approach
Transcritical CO2 Based Dedicated Mechanical Sub Cooling VCR
System: A Review
Pump as Turbine: Review of Simple Modifications for Performance
Improvement
Growth, Design Aspects and Applications of Photovoltaic Systems
76-82
2.
3.
4.
5.
16.
17.
18.
19.
20.
21.
Page No.
8-11
12-18
19-24
25-33
34-36
83-88
89-94
95-101
An Assessment of Wind Power Potential in Astana: A Wind Power 102-111
Plant Feasibility Study for Akmola Region, Kazakhstan
Energy efficiency of PV panels under real outdoor conditions – An 112-119
experimental assessment in Kazakhstan
Design and Performance Evaluation of Improved Biogas Stove 120-126
(IBS) by Preheating of Biogas
22.
127-133
26.
Empowering
Rural
Women
through
Renewable
Energy
Technologies
An Expert System for the Estimation of Direct Solar Radiation in
Indian Region
Parametric study of Pump as Turbine-2: Variation of Diameter of
Impeller
Renew your Inner Energy through Human Internal Energy
Sources: A Practitioner and Theoretical Approach
Renewable Energy Management for Smart Cities of India
27.
Design Aspects of Small Scale Wind Turbines: A Review
156-161
28.
On-Off Control Based Maximum Power Point Tracking of Wind 161-168
Turbine Equipped by DFIG Connected to the Grid
Advances in Green Composites: A Review
169-170
23.
24.
25.
29.
30.
31.
32.
33.
34.
35.
36.
37.
38.
39.
40.
41.
42.
43.
44.
45.
134-137
138-142
143-150
151-155
Nonlinear coupling of Inertial Alfvén waves and cavity formation in 171-175
low beta plasmas
Thermodynamic analysis of Factors affecting the Performance of 176-181
Solar Collectors
Reactive power control in distribution line by using D-STATCOM
181=186
State of Health Assessment of Lead Acid Cells as a Function of 187-192
Conductance
Control of Current and Voltage for Micro Grid
193-197
Reactive Power Compensation using Static Synchronous Series 198-201
Compensator (SSSC): A Review Paper
Induction Motor Protection System Using Fuzzy Logic
202-206
A Review Paper on Fuzzy Logic Based Speed Control of Induction 207-210
Motor
Renewable Energy Resources with Internet of Things
211-214
Renewable Energy Options and Possibilities to develop Banswara
as Energy Hub: A theoretical approach
Design Analysis of Distribution Power Network in ETAP-A Case
Study
Power system stability enhancement using fuzzy logic-based power
system stabilizer
Impact of Facts Device on Protective Distance Relay
215-224
225-229
230-234
235-239
Study and Review of Design and Simulation of CCM Boost 240-244
Converter for Power Factor Correction Using Variable Duty Cycle
Control
Dynamic Voltage Restorer for Power Quality Improvement
245-248
Design of Active Shunt Filter for Harmonics Reduction at Load 249-253
Side for Power Quality Improvement
46.
A Study on Speed Control of BLDC Motor Using Fuzzy Logic
47.
Hybrid Energy Management System design with Renewable Energy 258-262
Sources (Fuel Cells, PV Cells and Wind Energy): A Review
Comparative study of ATSMC and PTMC for a Single Phase SAPF
263-268
48.
49.
50.
51.
52.
53.
54.
55.
56.
57.
58.
59.
60.
61.
62.
63.
64.
65.
254-257
Combined Vector and Direct Power Control of Doubly Fed
Induction Generator- Based Wind Turbines: A Review Paper
Biomass-Diesel based Hybrid Electrical Supply System for Small
Network
Energy Conservation Options to Transport Solids at Higher
Concentration
Analysis of Process Characteristics for a Batch Production Unit
and Controlling the Variation for Effective Performances
Availability Analysis of Energy of Micro Hydro Power Plant with
Screw Archimedean Turbine in Indian Context
Solar Energy in India and National Solar Mission: A Review
269-273
Optimization Techniques Based Selective Harmonic Elimination
for Multilevel Inverter with Reduced Number of Switches
Techno-economic Analysis of Solar Photovoltaic Cooling System:
an analysis in four different climates in India
Effect of Renewable Energy on Green House Effect and
Environment: A Study
Fault Ride-Through Techniques of Wind Turbine State of Art: A
Review
Numerical solution to Natural convection in Triangular enclosures
and its application for double dome solar water distillation
systems
Solar Parks to Ramp up Solar Projects in the Country, Issues and
Challenges: Contribution towards Climate Change
Interconnected Hybrid RE Network with Embedded VSC - MTDC
Transmission System for Secure and Efficient Power Delivery:
Modeling and Steady State Response Analysis
Mitigation of Inrush Current in Power Transformer using
Prefluxing Technique
Analysis of Solar Thermal Cooling System Using TRANSOL
312-319
274-284
285-290
291-298
299-305
306-311
320-325
326-331
332-338
339-345
346-359
360-377
378-384
385-388
Analysis and Modeling of AC-DC Buck Converter Using PFC 389-395
Control Technique
Architectural and Technical Approach for Self-Sustainable 396-401
Building
***********
International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23,
2017 at GEC Banswara, www.apgres.in
ISBN-978-81-932091-2-7
1
International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23,
2017 at GEC Banswara, www.apgres.in
Short note for Conference
Apparently, the climate change is inextricably linked to future energy and necessitates a concerted
worldwide focus on the development and implementation of sustainable energy solutions. In the
coming decades, the energy sector will face an increasingly complex array of interlocking challenges
encompassing economic, geopolitical, technological, and environmental sectors.
Since the developing world’s population continues to expand, the energy needs of billions of additional
people in rural and especially urban areas will have to be met. Moreover, supplies of conventional oil
and conventional natural gas are expected to decline. Use of conventional energy resources, including
coal, will also have to be scrutinized since increasingly tight limits are being placed on the total amount
of greenhouse gases that can be released into the atmosphere. Eventually, solution to all our energy
related problems lies in the development of alternative energy sources and technologies.
The responses to this varied range of developments will play a crucial role in shaping trade and
investment flows, competitive positions, and the structure of economies across the globe, while
simultaneously determining mankind’s capacity to construct a sustainable future.
Meeting these challenges will require very long lead times. The objectives, in the context of future
energy, therefore are, renewing the existing patterns of energy production and consumption, transport
and other technical infrastructures, the layout of cities, the nature of the industrial capital stock, current
technologies, values and attitudes, etc.
I hope that the APGRES2017 conference shall lead the discussion in order to advance a global green
energy transition. Deliberations during the conference shall promote dialogues, innovation and the
international transfer of knowledge between stakeholders in civil, commercial, institutional and
government sectors. The conference will demonstrate ideas and solutions on energy recycling sources
and implementation of the principle "green economy" buildings, that generate energy for selfprovision, "smart houses", electric cars, automobiles on bio fuel and others.
Dr. Prashant Jamwal
Department of Electrical and Electronics Engineering,
School of Engineering, Nazarbayev University, Astana, Kazakhstan
ISBN-978-81-932091-2-7
2
International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)”
December 22-23, 2017 at GEC Banswara, www.apgres.in
Cascade Utilization of Energy and Exergy for the Performance
Analysis of a Solar Powered Cogeneration Cycle
1
Abdul Khaliq1*, Faizan Khalid2, Suhail A. Siddiaqui3
Mechanical Engg. Dept., King Fahd University of Petroleum and Minerals (KFUPM) Dhahran - 31261, Saudi Arabia,
2
Department of Mechanical Engineering, Gautam Buddha University, Greater Noida, U.P, India
3
Mechanical Engineering Department, Al-Falah School of Engg. & Tech., Dhauj, Faridabad, Haryana,
Corresponding Author: khaliqsb@gmail.com
Abstract
Present study focuses on the first and second law analyses of a solar based cogeneration system which
could simultaneously produce the electric power and refrigeration. An investigation is carried out to
ascertain the effect of varying the direct normal irradiation (DNI) and turbine back pressure on the
first law efficiency, cooling to power ratio and second law efficiency of the cogeneration system. The
results obtained indicate that variation in DNI and turbine back pressure have a considerable impact
on the second law performance of the cogeneration system while its first law performance is least
affected.
Nomenclature
E
Rate of exergy [W]
Q
Rate of heat transfer [W]
W
Rate of work output [W]
R / Cooling to power ratio
q
Solar radiation received per unit area
[W/m2]
Subscript
s
Sun
R
Refrigeration
El Electrical
c/p Cooling to power
ex exergy
1. Introduction
In order to utilize the solar thermal
energy for its potential in reducing fossil fuel
consumption and alleviating environmental
problems, the cogeneration cycles for
combined production power and cooling
have been explored for improving the overall
energy conversion efficiency. In this context,
a new combined power and cooling
thermodynamic cycle was proposed by
Goswami [2002]. This was a combined cycle
because it produces both power and cooling
simultaneously with only one heat source,
using ammonia-water mixture as the working
fluid. Other researchers [Dai et al.(2009),
Khaliq et al.(2012), Zhang and Li ( )] have
also investigated this new cycle from both
energy and exergy point of view where latter
provides a clearer assessment of various
losses occurring in energy systems both
quantitatively and qualitatively and thereby
shows the possibilities where improvements
in efficiency could be made. Hasan et al [ ]
presented the first and second law analysis of
the combined power and cooling cycle that
could use low temperature heat sources
below 200oC as a primary energy input and
ammonia-water mixture as a working fluid.
Li et al (2013) investigated the organic
Rankine cycle with ejector from first and
second law point of view and emphasized on
its thermo-organic performance at the
maximum net power output of the cycle.
Habibzadeh
(2013)
conducted
a
thermodynamic study on organic Rankine
cycle with ejector and evaluated its first and
second law performance for different
working fluids. They obtained the optimum
values of the turbine and pump inlet pressures
which minimize the total thermal
conductance of the system for working fluids
under consideration.
From the foregoing literature review,
it is noted that the majority of the previous
research is focused on the solar assisted
cogeneration cycle which combines the
organic Rankine cycle with an ejector and
utilized R-134a, R-113, R-123, R141b, R117, and R-609 etc. as the working fluids
which have the advantages of zero ozone
depletion potential, but they have higher
global warming potential and safety
problems as well as they produces lower
power output because of their smaller latent
heat of vaporization. In order to overcome
ISBN-978-81-932091-2-7
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)”
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with the aforementioned disadvantages, a
new cogeneration cycle was introduced
which combines the conventional Rankine
power cycle with a steam ejector. This cycle
used extraction steam from steam turbine in
conventional Rankine cycle to heat the
working fluid of the steam ejector
refrigeration cycle. Since water is used as a
working fluid for both power and cooling
production which has a zero-ozone depletion
potential and zero global warming potential
as well as have very good thermal
properties, therefore, this cycle could be
considered as one of the most suitable options
for harnessing the solar thermal potential of
the hot areas.
The performance
characteristics of solar based cogeneration
cycle using the solar power tower technology
are not well reported in the literature.
Therefore, the objective of the present work
is to investigate the performance of a
proposed cogeneration cycle using a
combined first and second law approach. A
parametric analysis is performed to examine
the effects of some influencing parameters on
the energy and exergy efficiency of the
cogeneration cycle. Numerical results are
graphed and commented upon.
2. Theoretical Analysis
Energy and exergy analyses of a solar
powered cogeneration system involve the
application of the principle of conservation of
mass and conservation of energy along with
the second law of thermodynamics and can
identifies and quantifies the sources of losses
and hence provides guidance for performance
improvement.
The relevant parameters required to
evaluate the energetic and exergetic
performance of the proposed cogeneration
cycle may be considered as follows:
2.1 Energy Utilization Factor (EUF)
The energy utilization factor is the
energy measure of efficiency and is simply a
ratio of useful output energy to input energy.
For cogeneration of electrical power and
cooling the energy utilization factor can be
defined as the ratio of all the useful energy
extracted from the system to the primary
energy input to the cycle, and may be
expressed as:
̇
̇
EUF =
=
̇
̇
̇
̇
where, 𝑄̇
is the rate of thermal energy
received by the heliostat and may be given as
𝑄̇
=𝐴 𝑞
2.2 Cooling to power ratio 𝐑 𝐂/𝑷
The effectiveness of the proposed
cogeneration system is directly related to the
amount of power it can generate for a given
amount of refrigeration produced. Therefore,
R / which is the cooling to power ratio
could be one of the important parameter to
assess the thermodynamic performance of a
given cogeneration system.
It is defined as:
R
=
/
̇
̇
In both energy utilization efficiency and
power to cold ratio, power and refrigeration
are treated as equal from the first-law of
thermodynamic point of view. This reflects
that parameters based on first-law are
concerned with the quantity of energy, not its
quality. Thus, EUF and R / are also known
as first-law efficiencies.
2.3 Exergy efficiency 𝐞𝐱 :
Exergy, or availability, which deals with the
quality of energy along with its quantity, can
be defined as the maximum amount of work
produced during the reversible transition of a
stream of a matter from its given
thermodynamic state to its dead state where it
is supposed to be in thermodynamic
equilibrium with the environment. Exergy
efficiency is the exergy output divided by the
exergy input to the cycle. It may be further
defined as:
=
̇
̇
̇
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)”
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where, 𝑊̇ is the exergy of electrical
power output and may be given as 𝑊̇ =
𝑊̇
where, 𝑊̇ is the exergy of electrical power
output 𝐸̇ is the exergy associated with the
rate of refrigeration produced, and 𝑄̇
is
the rate of exergy associated with the solar
radiations falling on heliostat field and may
be given as
𝐸̇
− 𝑄̇
1−
where 𝑇 is the apparent Sun temperature
which may be taken as 4500 K.
𝐸̇ = 𝑄̇
𝑇 −𝑇
𝑇
It is defined as the refrigerator capacity
divided by the COP of a Carnot refrigeration
cycle operating between 𝑇 − 𝑇 .
3.
Results and Discussion
The effects of DNI and turbine back pressure
is observed on the energyic and exergetic
performance of the proposed solar based
cogeneration. Numerical results are graphed
and comment upon and may be reported
below.
The effect of change in DNI on first law
efficiency and cooling to power ratio of the
cogeneration is shown in fig. 2. It is observed
that the first law efficiency increases with the
increase in DNI while cooling to power ration
decreases insignificantly with the increase in
DNI. This is because higher DNI causes a
greater turbine output and hence a higher
efficiency. Increase in turbine output is
greater than the increase in cooling output,
therefore, the cooling to power ratio increases
marginally with the increase in DNI. In order
to gain further insight into the performance of
the system, the effect of DNI is also observed
on the second law efficiency and the
exergetic cooling to power ratio of the
cogeneration which is shown in fig. 3. Both
second law efficiency and the exergetic
cooling to power ratio were found to be
increased considerably with the increase in
DNI. This is because increase in DNI as a
higher temperature source causes a greater
exergy output of the system. It is further
noticed that amount of exergy associated with
the cooling capacity is considerably less than
the energy and turbine power output gives
100%contribution to exergy, therefore, the
exergetic cooling to power ration also a
considerable increasing trend parallel to
second law efficiency.
The effect of change in turbine back pressure
is also investigated and is shown in fig. 4. It
is found that both first law efficiency and
cooling to power ration of the cogeneration
are significantly increased with the increase
in turbine back pressure. This is due to the
fact that as turbine back pressure increases,
the pressure ratio across the turbine decreases
which decreases the turbine power, but there
is an increase in motive steam pressure which
Environment Temperature(0C)
270C
Turbine inlet pressure (MPa)
8
Molten salt outlet temperature
567-644
range (0C)
Molten salt inlet temperature
290
0
( C)
Area of the heliostat, AH ( m2)
10000
Turbine isentropic efficiency
85
(%)
Generated efficiency (%)
95
0
Evaporator temperature, TE ( C) 7
increases the refrigeration capacity. Since the
increase in refrigeration capacity is greater
than the decrease in turbine power output,
therefore, both first law efficiency and
cooling to power ratio are increased
considerably with the increase in turbine back
pressure. The second law efficiency and the
exergetic cooling to power ratio shows the
opposite trend with the increase in turbine
back pressure. This is because the turbine
power output which gives 100% contribution
to exergy decreases while the exergy of the
refrigeration which is much less than the
refrigeration capacity decreases with the
increase in turbine back pressure. Therefore,
exergy output which is the sum of turbine
power and the exergy of the refrigeration
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)”
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decreases while exergetic cooling to power
ratio increases.
ηII (%), Cooling to Power ratio
ηI (%), Cooling To Power Ratio
35
30
25
First Law Efficiency [%]
20
Cooling to Power ratio
15
15
10
5
Second Law Efficiency [%]
Cooling to Power ratio
0
0.3
10
0.325
0.35
0.375
0.4
0.425
0.45
0.475
Turbine Back Pressure (MPa)
Figure 5
5
0
800
825
850
875
900
DNI (W/m2)
925
950
975
Figure 2
20
18
ηII (%), Cooling to Power ratio
20
16
14
12
10
Second Law Efficiency [%]
8
Cooling to Power ratio
6
4
2
0
800
825
850
875
900
925
950
975
DNI (W/m2)
Figure 3
Conclusion
In this paper, an analysis based on combined
first and second laws of thermodynamic was
performed for the solar based cogeneration
system which could produce both power and
cooling simultaneously. It was found that by
employing an ejector between the turbine and
condenser, thermodynamic performance of
the system increased. Results obtained after
the parametric investigation show that the
variation in DNI and the turbine back
pressure have a greater impact on the second
law performance of the cogeneration than its
first law performance. It is noted that second
law analysis provides an insight into the
system performance which first law analysis
alone cannot. The model presented for the
analysis in this paper can be used to assess the
thermodynamic performance of other kind of
cogeneration system.
ACKNOWLEDGEMENT
ηI (%), Cooling to Power ratio
35
The first author would like to acknowledge
the financial support provided through the
Project No. RG1330 under the Grant of
Research Group from DSR of King Fahd
University of Petroleum and Minerals, Saudi
Arabia.
30
25
First Law Efficiency [%]
Cooling to Power ratio
20
15
10
5
0
0.3
0.325
0.35
0.375
0.4
0.425
Turbine Back Pressure (MPa)
Figure 4
0.45
0.475
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[1] Xu F., Goswami D. Y., and Bhagwa S. S.,
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(3), 2002, pp. 233-246.
[2] Dia Y., Wang J., and Gao L., Exergy
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parametric
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and
optimization for a novel combined power and
ISBN-978-81-932091-2-7
6
International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)”
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ejector refrigeration cycle. Applied Thermal
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[5] Hasan A. A., Goswami D. Y., and
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[6] Xinguo L., Xiajie L., and Zhang Q., The
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[7] Habibzadeh A., Rashidi M. M., and
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[8] Bejan A., Fundamentals of exergy
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[9] Xu C., Wang Z., Li X., and Sun F.,
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ISBN-978-81-932091-2-7
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Modeling, simulation and performance analysis of monocrystalline and
polycrystalline panel.
Neelam Rathore, N.L. Panwar, Surendra Kothari, Kirtika Sharma
Renewable Energy Engineering Department, M.P.U.A.T, Udaipur, India
Corresponding Author: E-mail: neelamrathore79@gmail.com
ABSTRACT
This paper presents the modeling and simulation of photovoltaic model using MATLAB/Simulink
software package. Modeling and simulation is done for monocrystalline panel and polycrystalline panel
of 40 Watt having total 37 cells in which 36 cells were connected in series and 1 cell in parallel. For
both type of panels electrical characteristics is plotted and temperature effect is analyzed. Performance
analysis of mono-crystalline and poly-crystalline solar photovoltaic panels was done considering
certain parameters i.e. analysis of V-I curve, effect of variation in tilt angle on PV module power, effect
of shading on PV module power, effect of increase of temperature on PV module power, efficiency,
space efficiency and cost. Both the panels were compared on the basis of above parameters. The
proposed model is very useful for engineers who are dealing with PV system designing.
1.
INTRODUCTION
Photovoltaic (PV) is a method of generating
electrical power by converting solar radiation
into
direct
current
electricity
using
semiconductor by photovoltaic effect. The
modeling and simulation of photovoltaic (PV)
have made a great transition and form an
important part of power generation in this
present era [1]. The cost and the performance of
PV plants strongly depend on the modules. The
ideal photovoltaic module consists of a single
diode connected in parallel with a light
generated current source (ISC) as shown in
Figure 1 [1-2]:
Following equations were written in MATLAB
for the figure shown above Fig 1:
The ideal photovoltaic module consists of a
single diode connected in parallel with a light
generated current source (ISC) as shown in Fig
1:
I = ISC -I RS
Where ISC is photocurrent which is the lightgenerated current at the STP condition (25°C
and 1000W/m2).
The equations of Reverse Saturation Current
and photocurrent are given by [3 -4]:
I RS=Iscref[e (
]
ISC =[ Iscref+ K (T
Tref)]
The equation that describes the I-V
characteristic of the circuit in Fig1 is given by
ISC – ID –VD / RP - IPV = 0
Output of PV Module: It represents the output
current generated which depends on the PV
module voltage, solar irradiance on PV module,
wind speed, and ambient temperature. [4 -5]
Fig 1: Solar cell model using single diode with
RS
2.
MATHEMATICAL MODELLING
IPV = NPISC - NSIO{ exp (q(VPV + IPV RS)/
NSAKT) - 1} - VPV + (IPV RS / RP)
Where k is the Boltzmann constant (1.38 x 10 ^
-23 J K-1), q is the electronic charge (1.602 x
10 ^ -19 C), T is the cell temperature (K), A is
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the diode ideality factor, the series resistance R S
(Ω) and is the shunt resistance RP (Ω). NS is the
number of cells connected in series = 36. Np is
the number of cells connected in parallel and
VOC = V PV.
Theoretically observations were recorded using
MATLAB and practically characteristics were
plotted using “Solar PV Training and Research
Kit” shown in fig 2. Circuit diagram to analyze
V-I Characteristics is shown in figure3.
varying irradiance at 25° C
panel)
( Monocrystalline
Fig 6:MATLAB P-I characteristics for Varying
Irradiance at 25° C (Mono Panels)
Fig 2: Circuit diagram to analyze V-I
characteristics
3.
RESULTS AND DISCUSSION
3.1 V-I CHARACTERISTICS
V-I and P-I characteristics at 25˚C for both
types of panel were observed so that power can
be observed at any radiation using MATLAB as
shown in below figure 3 and 4.
Fig 7:MATLAB P-I characteristics for varying
Irradiance at 25° C (Mono Panels)
Irradiance at 25 ° C (Poly Panels)
Fig 3: MATLAB V-I characteristic for varying
irradiance at 25° C ( polycrystalline panel)
Fig 3: MATLAB V-I characteristic forfor
As it can be seen from graphs, at constant
module temperature, it can be observed that
with increase of solar irradiance, the shortcircuit current and open circuit voltage
increases. Therefore, higher the irradiation,
greater is the current. Contrary to the influence
of the solar irradiance, the increase in the
temperature around the solar module has a
negative impact on the power generation
capability. Table 1 shows that as temperature
increases power decreases but the decrement of
power is more for monocrystalline panel as
compared to polycrystalline panel. Another
parameter that gets affected is open circuit
voltage. As temperature increases open circuit
voltage decreases while short circuit current
does not very much.
Table 1: Effect of variation of temperature
on power (MATLAB results)
Temper
Open Circuit voltage
Power(watt)
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ature
(Volt)
Polycryst
alline
Panel
Monocrys
talline
Panel
Polycryst
alline
Panel
Monocrys
talline
Panel
25° C
22
22
37
39
50° C
21
17
35
28
75° C
19
15
31
24
3.2 EXPERIMENTAL ANALYSIS
(using “Solar PV Training and Research Kit”)
3.2.1 Effect of increase of temperature on PV
module power
Fig 7 is showing effect of increase of
temperature on PV module power for
monocrystalline and polycrystalline PV panel.
Here temperature is operating temperature of
solar panel which is always 25˚C greater than
ambient temperature. As temperature increases
power decreases but the decrement of power is
slightly lower for polycrystalline panel as
compared to monocrystalline panel.
Fig 9: Comparison Curve of temperature on PV
panels
3.2.2 Effect of shading on PV Module power
Readings were taken for 0 cell shading, 2 cell
shading, 4 cell shading, 9 cell shading and
power was observed at different shading. In
case of shading power decrement of 23.9% was
observed in polycrystalline while only 19.37%
of power was reduced in monocrystalline panel.
Monocrystalline panel is less affected by
shading and works well in shady condition as
compared to polycrystalline panel as power
drop was more in case of polycrystalline panel
during shading as shown fig 8.
Efficiency:
Power was observed for full day ( i.e. 7 a.m. to
5 p.m.) hence efficiency was calculated .
Efficiency of monocrystalline varies between
3% to 14% whereas from polycrystalline panel
it is 2.5% to 9.5%.
Fig 8: Curve showing effect of increase
showing effect of shading for both panels
3.2.3 Space Efficiency:
As two panels were considered while taking
observations for different parameters and the
area of monocrystalline panel was 0.18 m2
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while for that of polycrystalline panel was 0.20
m2 for 40 watts. Monocrystalline panel
occupies small space as compared to
polycrystalline panel for the same amount of
power. Monocrystalline panels supply power
about 222 Watt/m2 while polycrystalline
supplies power about 200 watt/m2.
3.2.4 Cost:
Now a days cost of both panels is decreasing.
Monocrystalline solar panels are expensive
because of its purity. Polycrystalline cells are
made up of multiple crystals and are
generally less expensive to manufacture than
mono cells.
4.
CONCLUSIONS
Power output from monocrystalline
panel is more than polycrystalline so
Monocrystalline panel tends to perform better
than similarly rated polycrystalline at low light
conditions.
Theoretically and Practically “Effect of
increase of temperature on PV module power
was observed and it was concluded as
temperature increases power decreases but the
decrement of power is slightly lower for
polycrystalline panel as compared to
Monocrystalline panel. When temperature was
increased from 25°C to 50°C power decreases
by 5.40 % in case of polycrystalline while in
case of monocrystalline power decrement of
28.20 % was observed.
Effect of shading on PV Module power
was done and it was observed that
monocrystalline panel is less affected by
shading and works better in shady condition as
compared to polycrystalline panel. In case of
shading power decrement of 23.9% was
observed in polycrystalline while only 19.37%
of power was reduced in monocrystalline panel
Both
monocrystalline
and
polycrystalline panels are good choices but
polycrystalline panel tends to be less space
efficient as Monocrystalline panel occupies
small space as compared to polycrystalline
panel for the same amount of power.
REFERENCES
1. Abdulkadir, M., Samosir, A.S. and Yatim, A.H.
M. 2012. Modeling and Simulation Based
Approach of Photovoltaic System in Simulink
Model, ARPN Journal of Engineering and
Applied Sciences, Vol. 7: 616-623.
2. Adamo,F., Attivissimo, F., Nisio,A.D., Lanzolla,
A.M.L. and Spadavecchia, M. September 6−11,
2009. Parameters Estimation for A Model of
Photovoltaic Panels, XIX I MEKO World
Congress Fundamental and Applied Metrolog:
964-967.
3. Basim Alsayid . 2012. Modeling and Simulation
of Photovoltaic Cell/Module/Array with TwoDiode Model, International Journal of Computer
Technology and Electronics Engineering, Vol. 1,
Issue 3: 6-11.
4. Bikaneria,J. Joshi,S.P. and Joshi, A.R. 2013.
Modeling and Simulation of PV Cell Using One
Diode Model, International Journal of Scientific
and Research Publications, Vol. 3, Issue 10: 1-4.
5. Chouder, A ., Silvestre,S., Taghezouit ,B. and
Engin Karatepe . 2012. Monitoring, modeling
and simulation of PV systems using LabVIEW,
Solar Energy ,1-12.
6. Das, D. and Pradhan, S.K. 2011. Modeling and
simulation of PV array with boost converter: an
open loop study, Unpublished B.Tech project
report submitted to Department of Electrical
Engineering, National institute of technology,
Rourkela.
7. Dev, A. and Jeyaprabha, S.B. 2013. Modeling
and Simulation of Photovoltaic Module in
MATLAB, Proceedings of the International
Conference on Applied Mathematics and
Theoretical Computer Science: 268-273.
8. Dunford ,W.G., Xiao, W. and Capel, A. 2004. A
Novel Modeling Method for Photovoltaic Cells,
35th Annual IEEE Power Electronics Specialists
Conference: 1950-1956.
9. Hadjab, M., Berrah, S. and Abid, H. 2012.
Neural network for modeling solar panel,
International Journal of Energy, Vol. 6, Issue 1:
9-16.
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Voltage and frequency controller for three Phase Four Wire Hybrid
System for Loads in Isolation
Mukesh Sahi, B.P. Chouhan
Government Polytechnic College Banswara, Rajasthan, India-327001
ABSTRACT:
Wind driven Self Excited Induction generator (IG) and Permanent magnet synchronous generator
(PMSG) along with Solar photovoltaic (SPV) power generating system are combined to feed the
variety of loads like linear/non-linear balanced/unbalanced loads in isolated regions. Powers from all
sources are combined at common coupling point with battery energy storage system (BESS).
Nonlinear and unbalanced loading condition demands reactive power from the system. Whole system
with load side controller is simulated in the MATLAB Simulink and the system performance is
evaluated during nonlinear and unbalanced loading condition. Source side controller maintains the
PMSG output maximum and also achieve a maximum torque for the maximum power tracking with
minimum currents.
KEYWORDS: Voltage Stability, Wind Turbine, Squirrel-Cage Induction Generator, PMSG, SPV,
Common Coupling Point, BESS.
synchronous generators (PMSG) are gaining
I.INTRODUCTION
popularity among the variable-speed wind
To cope up with the future power demand and
turbines [6]. A PMSG is a rotating electric
increased environmental concern, nowadays
machine, in which the field excitation is
focus is laid on electrical power generation
provided by permanent magnets. PMSGs have
from renewable energy sources such as wind,
a loss-free rotor and the power losses are
solar. These sources are the world’s fastest
confined to the stator windings and the stator
growing energy resources. These are clean and
core [7]. A multipole PMSG connected to a
effective modern technology that provides a
power converter can operate at low speeds and
beacon of hope for future energy based on
so gear can usually be omitted [8]. A gearless
sustainable and pollution free technology.
construction represents an efficient and robust
These renewable energy sources are located in
solution for a WECS. Thus, the efficiency of a
remote regions, thereby causing some
PMSG based WECS has been assessed to be
problems in their development. One solution
higher than other variable-speed wind turbine
for this is that if local small-scale power
systems.
systems are developed employing these
However, PMSGs have the disadvantage of
distributed energy sources, thereby reducing
high cost of permanent magnet material in
the transmission of the electricity over long
present time, which is expected to reduce in
distances. The autonomous or distributed
the near future. Full scale power converter is
generation systems can be used when the grid
used in the case of PMSG-based WECSs,
connection is not possible. In starting, during
which allows the full controllability of the
the development of the wind generation for
system [9]. The power converter decouples the
grid connected systems, the fixed speed wind
PMSG from the grid and results in an
turbines with squirrel cage induction
improved reliability. In the case of a gridgenerators were in use. For such systems the
connected variable speed WECS; the total
energy conversion efficiency was very low.
active power can be fed to the grid. For standNow a day's variable speed wind energy
alone systems [6] supplying local loads, if the
conversion system (WECS) [1-4] uses the
extracted power from the wind is more than
maximum power tracker (MPT) [5], which
the local loads (and losses), the excess power
enables to adjust the rotational speed to
is required to be diverted either to a dump load
maximize the wind turbine output power. The
or to be stored in the battery bank. So the study
turbines
driving
permanent
magnet
for three-phase four-wire autonomous WECS
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is important because most of the loads in
isolated areas, such as islands or remote
locations are single-phase distributed loads.
Another important renewable energy system is
solar photovoltaic (PV) generation system. Sun
irradiations are directly converted into electric
energy by the use of the PV array. As these
irradiations are available in huge amount for a
long period of time per day, so it must be
harnessed. Keeping it in mind, a system is
studied in MATLAB Simpower environment
which utilizes the solar energy and the wind
energy to supply an isolated area. WECS
through the self-excited induction generator is
also included in the proposed system. So, three
sources PMSG, IG and SPV are supplying the
power to the loads and these three sources are
joined in parallel at the common DC link.
II. SYSTEM
For the widely varying wind speeds the energy
conversion efficiency of fixed speed wind
energy conversion system (WECS) is very
low. In many of the modern-day variablespeed WECS, a maximum power tracker
(MPT) adjusts the rotational speed to
maximize the wind turbine output power. The
variable-speed operation of WECS can be
achieved in a number of ways. In the case of
doubly fed induction generator (DFIG) the
power converter needs to handle only the rotor
power, which is only a fraction of the total
power. Among the variable-speed wind
turbines, the turbine driving permanent magnet
synchronous generator (PMSG) is gaining
popularity. In PMSG, the field excitation is
provided by permanent magnets. PMSG have
a loss-free rotor, and the power losses are
confined to the stator windings and the stator
core only [10]. At low speed a gear can usually
be omitted if a multi-pole PMSG is used. This
gearless construction represents an efficient
and robust solution for a WECS. Thus, the
efficiency of a PMSG-based WECS is higher
than other variable-speed wind turbine
systems [11]. In the case of PMSG based
WECS, a full- s c a l e power converter is used,
which allows the full controllability of the
system. In such systems, the power converter
decouples the PMSG from the grid, resulting
in an improved reliability. For stand-alone
systems supplying local loads, if the extracted
power from the wind is more than the local
loads (and losses), the excess power is
required to be diverted either to a dump load
or to be stored in the battery bank. Moreover,
when the extracted power is less than the load
power, the deficit power needs to be supplied
from a storage element like a flywheel, a super
capacitor, compressed air, hydrogen storage, a
secondary battery [12]. A number of attempts
have been made to address the issues of
voltage and frequency control (VFC) for
stand-alone systems using asynchronous
generators [13] [14] [15] [16]. Attempts are
made to develop a battery-based controller
for a wind-driven autonomous four-wire
system using a PMSG and feeding local
loads in stand-alone mode without mechanical
position sensors. Further this autonomous
WECS using PMSG is considered in a hybrid
system with the Solar system using
photovoltaic array. As solar power is an
endless source of energy like wind energy, so
developing a hybrid system based on these
two freely available energies is a need of the
present world. The Three energy sources
PMSG, IG and SPV are connected in parallel
to a common DC bus line as shown in fig. 1,
through their individual converters. The load
may be dc-connected to the dc bus line or may
include an IGBT based pulse width modulated
(PWM) voltage source inverter to convert the
DC power into AC at 50 or 60 Hz. Each
source has its individual control. The diodes,
D1, D2 and D3, allow only unidirectional
current flow from the source to the DC bus
line, thus keeping each source from acting as a
load on each other or on the battery. Therefore,
in the event of malfunctioning of any of the
energy sources, the respective diode will
automatically disconnect that source from the
system. The output of the hybrid generating
system goes to the DC bus line to feed the
isolating DC load or to the inverter, which
converts the DC into AC. When the output of
the system is not available, the battery powers
the DC load or discharges to the inverter to
power AC loads.
III. PRINCIPLE
The operating principle of the controller which
controls the load-side converter is based on the
control of the reactive power to regulate the
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magnitude of the load voltage and control of
active power to regulate the frequency of the
voltage. The battery system absorbs the excess
active power when the frequency of the load
voltage is above the nominal frequency, and it
supplies the active power when the frequency
is below the nominal frequency. When the
magnitude of the voltage falls below the
reference value, the load-side converter
provides the reactive power, and when the
magnitude of the voltage rises above the
reference value, the reactive power is absorbed
by the load-side converter.
For the control of the load-side converter, the
reference
three-phase
phase-to-neutral
voltages are compared with the sensed threephase, phase-to-neutral voltages at the load
end, and the difference is fed to the voltage
controller. The output of the voltage controller
gives the reference three-phase load-side
converter currents, which are compared with
the sensed three-phase load-side converter
currents to achieve control signals for the load
side converter.
Fig. 1 Block Diagram for Proposed System
A.
Machine Side Converter Control
The operating principle of the controller for
the machine-side converter is based on the
decoupled control of the d-axis and q-axis
stator currents of the PMSG with the d-axis
aligned to the permanent magnet flux or rotor
electrical axis. In the proposed algorithm, the
wind speed is sensed for the MPT. The rotor
position (θ ) is estimated using stator flux
linkages. The equations and algorithm for the
sensor less operation are illustrated through
equation 1 to 6. The rotor speed (ω ) is
determined from the rotor position (θ ). The
reference rotor speed (ω∗ ) for the MPT is
generated from the wind speed and the
optimum tip speed ratio(TSR) and is compared
with (ω ) to calculate the rotor speed error
(ω ) at the nth sampling instant as:
ω ( ) = ω∗( ) −
ω ( ) … … … … … … … … … … … … … … … . (1)
At the nth sampling instant, the output of the
proportional-integral (PI) speed controller with
proportional gain K ω and integral gain K ω
gives reference for the q-axis stator current
(I ) as:
I∗ ( ) = I ( ) + K ω ω ( ) −
ω ( ) + K ωω ( ) …
… … … . … (2)
To obtain maximum torque with minimum
stator current, the reference d-axis stator
current (I∗ ) is set to zero at the nth sampling
instant as:
I∗ ( ) =
0 … … … … … … … … … … … … … … … … … . (3)
By dq to abc transformation, the reference d-q
stator currents (I∗ and I∗ ) are converted to
three-phase reference PMSG stator currents
(i∗ , i∗ and i∗ ), which are then compared
with sensed PMSG stator currents (isa,isb, and
isc) to compute the PMSG stator current errors
(isaerr,isberr, and iscerr) as:
i
= i∗ −
i … … … … … … … … … … … … … … … . … . . (4)
i
= i∗ −
i … … … … … … … … … … … … … … … … . (5)
i
= i∗ −
i … … … … … … … … … … … … … … … … . . (6)
These current errors are amplified with gain
(K) and the amplified signals are compared
with the fixed frequency (10 kHz) triangular
wave to generate gating signals for IGBTs of
the machine-side converter.
B. LOAD SIDE CONVERTER CONTROL
The purpose of the load-side converter is to
maintain rated voltage and frequency,
irrespective of connected load. The power
balance of the load-side converter is
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maintained by diverting excess power
carrier wave of unity amplitude to generate
generated to the battery in the DC link of backgating signals for IGBTs of the load-side
to-back connected PWM converters or by
converter.
supplying active power from the battery in the
IV. SIMULATION AND RESULTS
case of a deficit between the generated power
and load requirement. Similarly, the required
MATLAB simulation of the proposed system,
reactive power for the load is supplied by the
“Autonomous WECS using PMSG” (Wind
load-side converter to maintain a constant
Energy Conversion System using Permanent
value of the load voltage. The reference
Magnet Synchronous Generator), Solar
∗
∗
∗
Photovoltaic (SP) and Induction Generator
voltages (v , v and v ) for the control of
(IG) is done in MATLAB using Simulink,
the load voltages at time t are given as:
∗
SimPower System. The simulation is carried
(
)
(
)
v = √2V sin 2πft … … … … … … . . 7
∗
out on MATLAB version R2011a with
v = √2V sin(2πft −
ode23tb solver. Complete system for WECS
120° ) … … … … … … … … … … … . . … … … (8)
using PMSG, SP and IG in isolation is
v ∗ = √2V sin(2πft +
simulated by combining the simulated models
120° ) … … … … … … … … … … … ..
… . . (9)
of the WECS, SP, IG, Machine Side
Where, ‘f’ is the nominal frequency (50 Hz)
Controller, Load Side Controller, and Battery
and V is the RMS phase-to-neutral load
Energy Storage System (BESS) is shown in
voltage (240 V). The load voltages (v , v
fig. 2 here two back-to-back connected
and v ) are sensed as feedback signals and
insulated gate bipolar transistor (IGBT) based
error voltages (v
,v
and v
) are
voltage source converters (VSCs) are
calculated from the reference voltages and load
connected between the PMSG and the load
voltages as:
end. The VSCs are controlled through the
v
( ) =
pulse width modulation (PWM) based
v∗ ( ) v ( ) … … … … … … … … … . (10)
controllers. A battery bank is connected at
∗
the DC link of these VSCs. An LC filter and a
v
( ) = v ( )−
step-up-transformer are connected between the
v ( ) … … … … … … … … … … … … … 11)
load-side converter and the load.
∗
v
( ) = v ( )−
v ( ) … … … … … … … … … … … … . (12)
The reference three-phase load-side converter
currents (i∗ ,i∗ and i∗ ) are generated by
feeding the voltage error signals to the PI
voltage controllers.
The reference three phase load side converter
currents are then compared with sensed load
side converter currents (i , i
and i ) to
compute the load side converter current errors
as:
i
= i∗
−i
… … … … … … … … … … … … … … . . (13)
i
= i∗
− i … … … … … … … … … … … … … … . . (14)
i
= i∗
Figure 2: Simulation diagram for the system
− i … … … … … … … … … … … … … … … (15)
under consideration.
These current errors are amplified with gain
(K), and the amplified signals are compared
A. SOURCE SIDE CONTROLLER
with the fixed frequency (10 kHz) triangular
Tm
Discrete,
Ts = 5e-006 s.
powergui
m
Vabc_Wind
<Rotor speed (wm)>
C
A
B
C
72 kvar
Discrete
Mean value2
T6
Wind Turbine
0
Wind speed (m/s)
10
N
-
+
Tm (pu) Pitch angle (deg)
A
Grounding
Transformer
+
- v
B
Scope3
C
wind generation
Vabc_B1
Vabc
Iabc
Iabc_B1
Diode2
A
B
C
A
B
C
wind speed
PQ
Iabc
3-phase 1
Generator speed (pu)
Rectifire1
T
Wm
12
T7
Mean
(discrete)
Vabc
Iabc_Wind
Induction Generator
A
B
C
Te
Tm
Ws
B
wind
power1
Manual Switch
A
bB
cC
Wp
Speed
aA
PQ
Mean
(discrete)
Discrete
Mean value1
3-phase
R
T1
+
A
B
C
i
-
T2
3 kvar
Scope1
+v
-
Scope
[ILn_abc]
Goto
A
B
C
+
- v
PWM
IGBT Inverter
g
Balanced / Unbalanced
Linear / Non-Linear Loads
g
+
A
+
Diode1
A
A
A
a
A
B
B
B
B
b
B
C
C
C
C
c
C
-
DC BUS
Rectifire
+
i
-
i
-
Conn2
+i
-
n2
Three-Phase
Transformer
Measure1
Conn1
+
c
Conn4
Conn3
i
+
-
T3
-- ---
++++
2 mH
1
a
b
-
C
A
C
B
z
Vabc_B1
Vpu
+++
Iref
Iabc_B1
Signal(s) Pulses
---
I
Subsystem
Source Side
Controller
T5
BESS
From
Vlabc
T4
V1
Scope4
From5
Out1
ILabc
[ILn_abc]
Load Side
Controller
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The objective of the source side controller is
to achieve a maximum torque for the
maximum power tracking with minimum
currents. The graphs for the source side
converter are shown in fig. 3. The output of
the Wind turbine driven PMSG is maximized
by using maximum power tracking technique
and simulated as source side cont roller.
Graphs are plotted between the time and the
various observed quantities. The input and
output of the system are shown through the
graph placed in the fig 3. In fig.3 (a) graph
shows Cos and Sin values created through
PLL by using the three phase per unit voltages
generated by PMSG. These Cos and Sin values
are used to convert the ‘dq0’ values to three
phase ‘abc’ values. Fig. 3(b) & fig. 3(c)
represent the input and output values of the PI
controller respectively, ‘dq0’ to three phase
‘abc’ conversion is shown in fig. 3(d). Three
phase current generated through the PMSG is
shown in fig. 3(e). Fig. 3(f) shows the result of
subtraction of generated current shown in fig.
3(e) from the values shown in fig. 3(d). These
values are given to the PWM generator unit to
generate the switching pulses for the source
side controller. These switching pulses are
shown in fig. 3(g).
load-side converter to maintain a constant
value of the load voltage. The graphs for the
load side controller are shown in Fig. 7. In
fig. 7(a) the graph shows the three phase
reference voltage. Fig. 7(b) represents the
sensed three phase load voltage. The sensed
three phase load voltage is subtracted from the
reference three phase voltages and outcome is
shown in fig. 7(d), which is directly entered to
the PI controller. Fig. 7(e) shows the output of
the PI controller. Sensed three phase load
current is shown in fig.7 (e) is subtracted from
the output of the PI controller shown in fig.
7(d) and the result of subtraction is shown in
fig. 7(f). Then these values of fig. 7(f) are
given to the PWM generator unit to generate
the switching pulses for the load side
controller. These switching pulses are shown in
fig. 7(g).
Fig. 7 Load Side Controller
Fig. 3 Source Side controller
B. LOAD SIDE CONTROLLER
The objectives of the load-side converter are
to maintain rated voltage and frequency,
irrespective of connected load. The required
reactive power for the load is supplied by the
C. LINEAR LOAD
At starting the system is running with
balanced load. At 0.6 sec. an unbalance is
created by disconnecting the phase ‘a’ from
load, (by opening the connection between
phase ‘a’ and its load. This will reduce the
active power demanded by the load but cause
supply imbalance which affects the source.
Further at 0.7 sec. load form the phase ‘b’ is
also removed, making the system more
unbalanced. At 0.85 sec. both removed
phases loads are connected again which
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makes the system a balanced one again.
Behavior of the WECS using PMSG, IG and
SP is shown by a set of waveforms in fig. 8.
Here in the system during the unbalanced to
maintain the constant frequency on the load
side the extra active power is diverted to the
BESS. It is clearly seen from the graphs that
the load voltages for all three phases are in
balanced condition. The system frequency
remains always close to the 50 Hz.
Further at 0.7 sec. load form the phase ‘b’ is
also removed from its diode bridge rectifier
load, making the system more unbalanced. At
0.85 sec. both removed phases loads are
connected which places the system in the
previous condition. It is clearly visible in fig. 9
that the voltage and frequency are almost
constant even though during the disturbances.
V. CONCLUSION
Matlab/simulink based simulation of the
proposed system shows that the voltage and
frequency on load side remains balanced in all
electrical loading conditions. The performance
of the WECS using PMSG, IG, SPV system
feeding
balanced/unbalanced
resistive,
inductive, and non-linear load has been found
satisfactory.
REFERENCES
1.
Fig. 8 Graph for Linear
Balanced/Unbalanced Load
D. NON-LINEAR BALANCED/
UNBALANCED
System is started with balanced three phase
load. At 0.6 sec. an unbalance is created by
disconnecting a diode bridge rectifier load
from phase ‘a’ (by opening the connection
between phase ‘a’ and its load).
2.
3.
4.
5.
.
Fig. 9 Graph for Non-linear Balanced
/Unbalanced Load
T. F. Chan, and L. L. Lai, “Permanent
magnet machines for distributed power
generation: A review,” IEEE Proceedings
of the Power Engineering Society General
Meeting, pp. 1–6, June 2007.Rolan, A.
Luna, G. Vazquez, “Modeling of variable
speed wind turbine with a perman
ent magnet synchronous generator”,
IEEE International Conference on Electric
Machines and Drives, pp. 734-739, July
2009.
P. K. Goel, B. Singh, S. S. Murthy, N.
Kishore, “Isolated wind-hydro hybride
system using cage generators and battery
storage,” IEEE Transactions on Industrial
Electronics, Vol. 58, No. 4, pp. 11411153, April 2011.
M. Abdel-Salam, A. Ahmed, M. AbdelSater, “Harmonic mitigation, maximum
power point tracking, and dynamic
performance of variable-speed gridconnected wind turbine,” Electric Power
Components and System, Vol. 39, No. 2,
pp. 176-190, 02 Feb. 2011.
X. Yang, X. Gong, and W. Qiao,
“Mechanical sensorless maximum power
tracking control for direct drive PMSG
wind turbine”, IEEE Energy Conversion
Congress and Exposition, pp. 4091-4098,
sep. 2010.
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6.
7.
8.
9.
10.
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13.
P. K. Goel, B. Singh, S. S. Murthy, and
N. Kishore, “Autonomous hybrid system
using SCIG for hydro power generation
and variable speed PMSG for wind power
generation”, IEEE Conference on Power
Electronics and Drive Systems, pp. 55-60,
nov. 2009.
J. Faiz, B. M. Ebrahimi, M. rajabisebdani and A. Khan, “Optimal design of
permanent magnet synchronous generator
for wind energy conversion considering
annual energy input and magnet volume”,
IEEE Conference on Sustainable Power
Generation and Supply, pp. 1-6, april
2009.
S. Miyabukuro, M. Takiguchi,and R.
Takhashi, “Modeling and simulation of
wind turbine –fed interior permanent
magnet synchronous generator”, IEEE
Conference on Electrical Machines, pp. 16, sept. 2008.
M. Chinchilla, S. Annaltes, and J. C.
Burgos,, “Control of permanent-magnet
generators applied to variable-speed wind
energy systems connected to the grid,”
IEEE Transactions on Energy Conversion,
Vol. 21, No. 1, pp. 130–135, March 2006.
E. Spooner, A.C. Williamson, G. Catto,
"Modular design of permanent magnet
generators for wind turbines," IEE
Proceedings, Electric Power Applications,
Vol.143, No. 5, pp. 388-395, Sep. 1996.
J. Chen, C.V. Nayar, and L. Xu, "Design
and finite-element analysis of an outer
rotor permanent-magnet generator for
directly coupled wind turbines," IEEE
Transactions on Magnetics, Vol. 36, No.5,
pp. 3802-3809, Sep 2000.
K. Stunz, and J. Nedrud, “Multilevel
energy storage for intermittent wind
power conversion: Computer system
analogies,” IEEE Power Engineering
Society General Meeting, pp. 1950–1951,
San Francisco, CA, 12–16 June 2005.
E. Mulzadi, and T. A. Lipo, “Series
compensated PWM inverter with battery
supply applied to an isolated induction
generator,” IEEE Transactions Industry
Applications, Vol. 30, No. 4, pp. 1073–
1082, July/August 1994.
14. R.S Bhatia., D.K Jain., Bhim Singh and
S.P. Jain, “Battery energy storage system
for power conditioning of renewable
energy sources”, in Proc. of IEEE
Conference on Power Electronics and
Drive Systems, Dec. 2005, pp.501-506.
15. V. Valtchev, A. V. D. Bossche, J.
Ghijselen,
and
J.
Melkebeek,
“Autonomous
renewable
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Energy,Vol. 19, No. 1/2, pp. 259–
275, January 2000.
16. C. H. Lee and L. Wang, “A novel
analysis of parallel operated self-excited
induction enerators”, IEEE Transactions
on Energy Conversion, vol. 13, No.2, pp.
117123, June 1998.
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Effect of Heat Transfer Fluids on the Techno-Economic Performance
of Parabolic Trough based Solar Thermal Power Generation in India
Tarun K. Aseria, Chandan Sharmaa, Ashish K. Sharmab, Rahul Rawatc
a
Mechanical Engineering Department, Govt. Engineering College, Ajmer, Raj., India.
b
International Finance Corporation (IFC), World Bank Group, New Delhi, India
c
Ministry of New and Renewable Energy, New Delhi, India
Abstract
The share of renewable energy based electricity generation in total energy mix in India is increasing
day by day owing to climatic concerns and resource scarcity associated with fossil fuels. Solar thermal
is a prominent option for renewable energy based power generation. The solar thermal technologies
like parabolic trough, central tower receiver and linear Fresnel reflector are being used to generate
electricity in the different part of the world. In the present study, the effect of heat transfer fluids
(Solar salt, Hitec XL, Therminol VP-1, Hitec) on techno-economic performance of a 50MW parabolic
trough based solar thermal power plant (without thermal energy storage) has been analyzed. The
location of Jaisalmer in the state of Rajasthan, India has been considered for the analysis. Annual
energy output has been obtained using System Advisor Model (SAM) simulation tool. Levelized cost
of electricity (LCOE) has been computed. The results obtained reveals that Hitec–XL heat transfer
fluid provides highest annual electricity output and correspondingly lowest LCOE in comparison to
other heat transfer fluids considered in the study.
Keywords: Solar thermal power generation; parabolic trough; heat transfer fluid; levelized cost of
electricity.
(Sharma et al., 2015). Kumar and Reddy
(Reddy and Kumar, 2012) have assessed
1.
INTRODUCTION
feasibility of solar thermal power plant at 58
High rate of GHG emissions and resource
potential locations using synthetic oil and
scarcity concerns associated with fossil fuel
water as working fluids in solar parabolic
based electricity generation has renewed the
trough field. The study observed that PTC
interest of researchers to explore renewable
based solar thermal power plants are
energy sources for electricity generation (Pitzeconomically viable in India. Feldhof et al.
Paal et al., 2003). Solar energy based power
(Feldhoff et al., 2012, 2010) have carried out
generation is one of the promising noncomparative studies for PTC based solar
conventional energy source. Two routes are
thermal power plant using water/steam and
available to harness solar energy and convert
synthetic oil as HTF with and without TES
into electrical energy. These are: Solar PV and
system. As reported, using direct steam
solar thermal (IRENA and ETSAP, 2013;
generation (DSG) could lead to reduction in
REN21, 2016). The concentrating solar power
cost of energy delivered by 11% without TES.
(CSP) can play a significant role in shifting
Further, recent research is focused on
carbon rich energy sector to green energy
enhancing thermodynamic performance of
sector. Moreover, the option of incorporating
solar thermal power plant using different kind
relatively inexpensive thermal storage with
of heat transfer fluid using nano particles
solar thermal power plant is expected to
(Cingarapu et al., 2013; Fernández et al., 2014;
improve it’s dispatch ability (Sargent &
Tiznobaik and Shin, 2013).
Lundy, 2003). Several studies have analysed
Though numerous studies have envisaged
and assessed the effect of various design
significant potential of solar thermal power
parameters such as collector field, design
generation in India (Purohit et al., 2013;
direct normal irradiance (DNI), solar multiple
Ramachandra et al., 2011; Sharma et al.,
(SM), thermal energy storage (TES), type of
2014), very few studies have been reported that
heat transfer fluid (HFT) on techno-economic
deals with study of effect of design parameters
performance of solar thermal power plant
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on the techno-economics of solar thermal
power generation. In the present study, an
attempt has been made to investigate the effect
of heat transfer fluids (Solar salt, Hitec XL,
Therminol VP-1, Hitec) on techno-economic
performance of a 50MW parabolic trough
based solar thermal power plant in India. The
plant without thermal energy storage has been
chosen for the study.
2.
Site selection for the study
The analysis of the techno-economic
performance of solar thermal power plants in
India is primarily based on available annual
direct normal irradiance (DNI) in the region.
As reported, the locations with annual DNI
more than 1800 kWh/m2 are technically and
economically viable for deployment of solar
thermal power plants (Purohit and Purohit,
2017). Figure 1 shows the distribution map of
the daily average DNI for India. It is observed
that most of the northern-western region is
having high DNI and hence significant
potential for solar thermal power generation
exist. . The site selected for the present analysis
is falling in the same region. The geographic
and environmental characteristics of the
potential location i.e. Jaisalmer in the state of
Rajasthan is summarized in Table 1. The
monthly variation of ambient temperature and
DNI for the location of Jaisalmer is presented
in Figure 2.
3.
PTC based solar power plant
Majority of operational solar thermal power
plants across the globe are parabolic trough
based as the technology is relatively more
mature than central tower receiver and linear
Fresnel reflector. Further most of the
operational plants are of 50 MW nominal
capacity. Hence, a 50 MW parabolic trough
based solar thermal plant has been considered
in the study. A schematic flow diagram of the
50MW Rankine cycle based solar thermal
power plant is shown in Figure 3. In this cycle,
the cold heat transfer fluid (HTF) gets heated
in the solar collector field by incident solar
radiation. This heated heat transfer fluid
exchanges its heat and convert water into
superheated steam in the steam generator. This
high pressure (100 bar) and high temperature
(375°C) steam is expanded in various stages of
various turbines i.e. high pressure (H.P.),
intermediate pressure (I.P.) and low pressure
(L.P.) turbine. The outlet steam from the L.P.
turbine is condensed back into water in the
condenser and recycled to steam generator
using feed water pumps and heaters.
In the present study, the technical data
pertaining to one of the operational 50 MW
PTC based solar thermal plant (Megha solar
power plant located in Anantpur, Andhra
Pradesh) has been taken for evaluation of
electricity output and same are presented in
Table 2.
4.
Heat transfer fluids
The selection of optimum heat transfer fluid
(HTF) is important aspect for overall technoeconomic performance and efficiency of CSP
plant over its entire useful life. Besides
exchanging heat in steam generator, the HTF
can also be used as thermal storage media to
generate electricity in hours of no or
intermittent sunshine.
The selection of
appropriate HTF depends on several desired
physical characteristics including higher
thermal stability at higher temperature, high
thermal conductivity and boiling point, low
viscosity and melting point, low corrosive
nature and low cost (Batuecas et al., 2017).
High heat capacity for storage is essential
characteristic of HTF (González-Roubaud et
al., 2017a). Based on material used, the heat
transfer fluids can be : (a) water/steam, (b)
thermal oils, (c) organic fluids, (d) molten
salts, (e) liquid metals and (f) air/other gases
(Vignarooban et al., 2015). In the present
study, the performance CSP plant with
commonly used thermal oil (Therminol VP-1)
as HTF has been compared with three different
molten salts. Table 3 presents characteristics of
heat transfer fluids selected for the analysis.
5.
Economic analysis
As mentioned earlier, the Megha Solar Plant
has been chosen as reference plant and capital
cost (US $2690/kW) of same has been
considered for the analysis (SolarPACES,
2016). The capital cost used in the study is
adjusted for the present year (i.e. 2017)
(Decelerates and Flatten, 2017). The levelized
cost of electricity (LCOE) has been estimated
from the following expression (Kandpal and
Garg, 2003):
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LCOE
(Capitalcost capitalrecoveryfactor) annualO & M cost
Annualelectricity output
(2)
Capital recovery factor (CRF) is given by:
d (1 d ) n
CRF
(1 d ) n 1
(3)
where d is discount rate and n is useful life of
the plant. In the present study, a discount rate
of 10%, useful life of 25 years has been
assumed. Annual operation and maintenance
(O&M) cost has been assumed as 2% of the
capital cost.
Table 1
Details of location selected for the analysis
Latitude
oE
Longitude
o
Wasteland
26.91
N
70.95
2
km
16762
2
DNI
kWh/m
1883
Dry bulb Temperature
Wind speed
(ºC)
m/s
28.65
4.89
Rainfall
mm
181.2
Figure 3: Schematic of solar thermal power plant
Figure 1: Daily average direct normal irradiance map
for India
Ambient temperature
40
240
35
220
30
180
20
160
15
140
10
Dec
Oct
Nov
Sep
Jul
Aug
Jun
Apr
100
May
0
Mar
120
Jan
5
Figure 2: Monthly variation of ambient
temperature and direct normal irradiance
DNI (W/m²)
200
25
Feb
Ambient temperature (ºC)
DNI
Table 2
Design parameters used in simulation for 50MW PTC
based solar thermal power plants(SolarPACES, 2016)
Parameter
Value
Collector
AlbiasaTrough AT150
Receiver
Siemens UVAC 2010
Heat Transfer fluid
Therminol VP-1
Irradiation at Design (W/m2)
700
Solar multiple
1.20
Reflected area (m2)
366,240
Land Area (km2)
1.3
Year to year decline in
Nil
output
Table 3
Characteristics of heat transfer fluids (González-Roubaud
et al., 2017b; Jung et al., 2015)
Heat
Thermin
Solar
Hitec
transfer
Hitec
ol VP-1
salt
XL
fluid
NaNO3
NaNO3
C12H10
NaNO3
(7),
(7),
Compositio
(73.5),
(60),
KNO3
KNO3
n (wt%)
C12H10O
KNO3
(45),
(53),
(26.5)
(40)
Ca(NO3) NaNO2
(40)
2 (48)
Minimum
operating
12
238
120
142
temperature
o
( C)
Maximum
400
593
500
538
operating
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6.
764.3
1871.8
1956.5
1828.6
2.457
1.502
1.432
1.56
0.00059
0.0032
6
0.00637
0.0031
6
Results and discussion
The annual electricity output for the proposed
solar thermal plants has been obtained using
system advisor model (SAM). SAM is
freeware renewable energy technology
simulation tool and is developed by the
National Renewable Energy Laboratory
(NREL), USA (SAM, n.d.). The National
Solar Radiation Database (NSRDB) source has
been used for weather data (NREL - NSRDB,
n.d.). The monthly energy output obtained for
a 50MW PTC based solar thermal power plant
using different heat transfer fluids is presented
in Figure 4. It is observed that the variation in
energy output follows the variation in monthly
DNI values. Table 4 summarizes annual
energy output, capacity utilization factor
(CUF) and levelized cost of electricity (LCOE)
for plant with different HTFs. As shown in the
Table 4, the plant with Hitec – XL HTF
generate relatively higher annual electricity
output and hence minimum LCOE amongst the
other HTF (Figure 5). The primary reason for
the same can be attributed to relatively
superior thermodynamics properties.
Therminol VP-1
Solar Salt
Hitec
Hitec XL
Energy output (GWh)
14.00
12.00
10.00
8.00
6.00
4.00
2.00
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
0.00
Months of the year
Figure 4 Monthly variation in energy output
Table 4
Annual energy output, capacity utilization and cost
of energy delivered with different HTFs
Annual
Heat
Electricity
CUF
LCOE
transfer
output
(%)
(₹/kWh)
fluid
(GWh)
Therminol
105.5
24.1
10.8
VP-1
Solar Salt
107.0
24.4
10.6
Hitec
103.3
23.6
11.0
Hitec XL
110.8
25.3
10.3
11.2
11.0
LCOE (₹/kWh)
temperature
(oC)
Density
(kg/m3)
Specific
heat
(kJ/kgK)
Kinematic
viscosity
(at 300 oC)
(Pa-s)
10.8
10.6
10.4
10.2
10.0
9.8
Therminol Solar Salt
VP-1
Hitec
Hitec XL
Figure 5 Variation in levelized cost of electricity for
different HTFs
7.
Concluding remarks
An attempt has been made to analyze the effect
of various heat transfer fluids on the technoeconomics of a 50 MW solar thermal power
plant in India. The location of Jaisalmer in
Rajasthan has been selected for the same.
Technical data pertaining to an operational
plant in India has been used. Four different
heat transfer fluids were used, and it was found
that annual electricity output with the use of
Hitec XL is maximum (Rs. 110.8 GWh) and
LCOE is minimum (Rs. 10.3 per kWh).
Further, annual electricity output with the use
of Hitec heat transfer fluid is minimum (103.3
GWh) and LCOE is maximum (Rs. 11.0 per
kWh). This reveals that among other
parameters, the selection of proper heat
transfer fluid has considerable impact on
annual electricity output and cost of electricity
delivery.
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Purohit, I., Purohit, P., 2017. Technical
and economic potential of concentrating
solar thermal power generation in India.
Renew. Sustain. Energy Rev. 78, 648–
667. doi:10.1016/j.enpol.2010.01.041
Purohit, I., Purohit, P., Shekhar, S., 2013.
Evaluating the potential of concentrating
solar power generation in Northwestern
India. Energy Policy 62, 157–175.
doi:10.1016/j.enpol.2013.06.069
Ramachandra, T.V., Jain, R., Krishnadas,
G., 2011. Hotspots of solar potential in
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3178–3186.
doi:10.1016/j.rser.2011.04.007
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collector field design and viability
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power plants for Indian conditions.
Energy Sustain. Dev. 16, 456–470.
doi:10.1016/j.esd.2012.09.003
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22-23, 2017 at GEC Banswara, www.apgres.in
https://sam.nrel.gov/download (accessed
3.3.17).
20. Sargent & Lundy, 2003. Assessment of
Parabolic Trough and Power Tower Solar
Technology Cost and Performance
Forecasts:NREL/SR-550-34440, National
Renewable Energy Laboratory (NREL).
21. Sharma, C., Sharma, A.K., Mullick, S.C.,
Kandpal, T.C., 2015. Identifying Optimal
Combinations of Design for DNI, Solar
Multiple and Storage Hours for Parabolic
Trough Power Plants for Niche Locations
in India, in: Energy Procedia. pp. 61–66.
doi:10.1016/j.egypro.2015.11.478
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Kandpal, T.C., 2014. Assessment of solar
thermal power generation potential in
India. Renew. Sustain. Energy Rev. 41.
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Determination of optimum heat rejection pressure in transcritical N 2O
refrigeration cycle with vortex tube
1
Gaurav Jain, 2Akhilesh Arora, 3S. N. Gupta
1
Department of Mechanical Engg., JSS Academy of Technical Education, Noida, UP 201301,
2
Department of Mechanical Engineering, Delhi Technological University, Delhi 110042,
3
Department of Mechanical Engineering, IIT, BHU, Varanasi, UP 221005, India
Corresponding author E-mail: gauravjain@jssaten.ac.in
Abstract
In a transcritical vapour compression cycle heat rejection pressure plays an important role and it has an
optimum value corresponding to the maximum coefficient of performance (COP) of the cycle. In the
present paper, with a thermodynamic simulation model, the optimum heat rejection pressure has been
studied for the transcritical cycle with vortex tube (TCVT) having refrigerant N 2O. The effects of various
parameters (compressor efficiency, vortex tube nozzle efficiency, gas cooler outlet temperature,
evaporator temperature, cold mass fraction and water inlet temperature to desuperheater) on the optimum
heat rejection pressure are analyzed. Based on the cycle simulations, correlation of the optimum heat
rejection pressure in terms of appropriate parameters have been developed for considered operating
conditions. The correlation offers significant help in the design and control of the transcritical N 2O
refrigeration cycle with vortex tube.
Keywords: Refrigeration cycle, Nitrous oxide, Vortex tube, expansion valve, Optimum heat rejection
pressure.
List of symbols
COP
Coefficient of performance
ℎ
Specific enthalpy (kJ kg-1)
𝑃
Pressure (MPa)
𝑞
Cooling effect (kJ kg-1)
𝑡
Temperature (0C)
TCEV Transcritical cycle with expansion
valve
TCVT Transcritical cycle with vortex tube
𝑥
Dryness fraction
Greek letters
µ
Cold mass fraction
𝜂
Compressor isentropic efficiency
𝜂
Vortex tube nozzle efficiency
𝜀
Effectiveness of desuperheater
Subscripts
𝑏
Cycle with expansion valve
𝑐
Gas cooler outlet
e
Evaporator
𝑚
Cycle with vortex tube
opt
Optimum
𝑟
Improvement (%)
𝑤𝑑
Water inlet to desuperheater
1-9
State points of refrigerant
1. Introduction
The applications of natural refrigerants such as
carbon dioxide, nitrous oxide, propane,
isobutene, ammonia is gaining their importance
due to their zero-ozone depletion potential
(ODP) and low global warming potential
(GWP). In transcritical refrigeration cycles
carbon dioxide (CO2) has already gained large
acceptance, whereas its counterpart nitrous
oxide (N2O) is still not fully explored. N2O and
CO2 have similar properties in terms of critical
pressure, temperature and molecular weight
(Kruse et al. 2006). The N2O exhibits five times
lower toxicity than CO2, however its GWP (240)
is higher than CO2 (1) but it falls under the low
GWP category (Agrawal et al. 2011).
Some studies have been reported on use of N2O
in transcritical refrigeration systems (Sarkar and
Bhattacharyya, 2010; Agrawal et al., 2011). In
the mentioned studies, it is shown that
transcritical N2O cycle performs higher cooling
COP, lower discharge pressure and temperature
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with higher exergetic efficiency compared to
equivalent transcritical CO2 cycle.
The transcritical vapour compression cycle has
heat rejection process in supercritical region and
evaporation process in subcritical region.
Therefore, the expansion loss in the throttle
valve from the high pressure transcritical region
into the two-phase region is not so small. The
loss of this useful energy can be overcome by
using the vortex tube in place of expansion valve
in transcritical refrigeration cycle. The studies
on vortex tube expansion transcritical cycles
shows that vortex tube instead of expansion
valve in transcritical cycle improves the
maximum COP and reduces the optimum heat
rejection pressure (Li et al., 2000; Christensen,
2001; Sarkar, 2009; Xie et al. 2011; Liu and Jin,
2012; Jain et al. 2017).
Heat rejection pressure is an important
parameter in transcritical refrigeration cycle, and
it has an optimum value corresponding to
maximum COP. The optimum heat rejection
pressure in transcritical cycle with expansion
valve (TCEV) has been investigated by many
researchers (Kauf, 1999; chen et al. 2005; Aprea
et al. 2009; Cecchinato et al. 2010). Sarkar
(2009) also developed expressions for optimum
heat rejection pressure for vortex tube expansion
transcritical CO2 refrigeration cycles based on
maurer and keller models. However, the
correlation for optimum heat rejection pressure
for transcritical cycle with vortex tube (TCVT)
using N2O as refrigerant is scarce in open
literature.
In the present study, the analyses have been done
on the optimum heat rejection pressure based on
the maximum COP for the vortex tube expansion
transcritical N2O cycle with layout based on
maurer model (1999). A correlation for the
optimal heat rejection pressure has been
developed in terms of system operating
parameters. The correlation can provide a
guideline to the system design and optimization
of a transcritical N2O cycle with vortex tube.
2. Transcritical N2O refrigeration cycle with
vortex tube
A transcritical N2O refrigeration system consists
of a compressor, a gas cooler, an evaporator, and
an expansion device. The expansion device can
be either a throttle valve or vortex tube. The
schematic diagram of transcritical cycle with
vortex tube (TCVT) for Maurer model (1999) is
shown in Fig.1 and the corresponding P − h
(pressure-enthalpy) diagram is shown in Fig. 2.
Fig. 1 Schematic diagram of transcritical cycle
with vortex tube for Maurer Model
Fig. 2 P-h diagram of transcritical cycle with
vortex tube for Maurer Model
As shown in Fig. 1, the superheated refrigerant
N2O enters the compressor at state 1 and
compressed adiabatically to state 2. The
superheated gas is then cooled to state 3 in a gas
cooler. The refrigerant coming out from the gas
cooler expands through the vortex tube nozzle
(state3a) and separates into three parts i.e.
saturated vapour (state 5), superheated vapour
(state 6) and saturated liquid (state 4). The
saturated liquid collects in a ring inside the
vortex tube. The saturated vapour and liquid are
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mixed again (state 8) at the inlet of evaporator.
In the evaporator the refrigerant N2O absorbs the
heat and converts into saturated vapour (State 9).
The superheated vapour (state 6) is sensibly
cooled in the desuperheater to state 7 and mixed
with the saturated vapour leaving the evaporator
(state 9) before entering the compressor (state 1).
In the transcritical cycle with expansion valve
(TCEV) the refrigerant enters the compressor as
saturated vapour (state 9) and exits at state 2b,
which is shown by a dotted line in Fig. 2. The
expansion in the throttle valve (expansion valve)
is isenthalpic (process 3-y is not shown in P-h
diagram).
3. Thermodynamic modeling and Simulation
The thermodynamic model based on
conservation of mass and energy as proposed by
Sarkar (2009) is considered for the analysis.
Following assumptions are made for analysis:
(i) The refrigerant leaving the vortex tube
separates into three parts; saturated vapour (state
5), saturated liquid (state 4) and superheated
vapour (state 6).
(ii) The pressure drops in various components
and connecting pipes of the system are
neglected.
(iii) The mixing and separation processes in the
cycle are isobaric.
(iv) The process inside the compressor is
irreversible adiabatic.
(v) The refrigerant at the exit of evaporator is dry
saturated vapour.
(vi)The hot fluid leaving the vortex tube absorbs
all the kinetic energies.
The mass of the refrigerant (N2O) coming out
from the gas cooler has been taken as one kg for
analysis. Suppose dryness fraction of refrigerant
at state 3a is ‘𝑥’ and the cold mass fraction is ‘µ’.
Then fraction [𝑥 ∗ µ] is separated as saturated
vapour, liquid [1 − 𝑥] is separated as saturated
liquid and rest [𝑥 ∗ (1 − µ)] absorbs all the
kinetic energies and separated as superheated
vapour.
The actual enthalpy at exit of vortex tube
nozzle can be calculated using equation (1).
ℎ = ℎ − 𝜂 (ℎ − ℎ )
(1)
Where 𝜂 is the nozzle efficiency of vortex
tube,
Energy conservation equation for vortex tube is
given by equation (2).
ℎ = (1 − 𝑥)ℎ + µ𝑥ℎ + (1 − 𝜇)𝑥ℎ (2)
Energy conservation at the inlet of Evaporator
(1 − 𝑥 + 𝜇𝑥)ℎ = (1 − 𝑥)ℎ + 𝜇𝑥ℎ (3)
Using the effectiveness of desuperheater 𝑡 can
be calculated by equation (4)
𝑡 = 𝑡 − 𝜀 (𝑡 − 𝑡 )
(4)
Where 𝜀 is the effectiveness of superheater
and 𝑡 is the temperature of water at inlet to
desuperheater,
Energy conservation at the inlet of compressor
ℎ = (1 − 𝑥 + 𝜇𝑥)ℎ + (1 − 𝜇)𝑥ℎ (5)
Cooling capacity of the system is given by
equation (6)
𝑞 = (1 − 𝑥 + 𝜇𝑥)(ℎ − ℎ )
(6)
Compressor work
𝑤 = ℎ − ℎ = (ℎ − ℎ )/𝜂
(7)
Where 𝜂 is the isentropic efficiency of the
compressor
The COP of the transcritical cycle with vortex
tube can be evaluated using equation (8)
(
)(
)×
𝐶𝑂𝑃 = =
(8)
The COP of the basic cycle i.e. transcritical cycle
with expansion valve (TCEV) is computed using
equation (9)
𝐶𝑂𝑃 = (ℎ − ℎ )/(ℎ − ℎ )
(9)
The percentage COP improvement with vortex
tube over expansion valve is given by
𝐶𝑂𝑃 = (𝐶𝑂𝑃 − 𝐶𝑂𝑃 ) ∗ 100/𝐶𝑂𝑃
(10)
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From equation (8), the COP of the transcritical
cycle with vortex tube has maximum value when
the partial derivative of the COP with respect to
the heat rejection pressure (𝑃) is equal to zero
Water temperature at inlet to desuperheater
(𝑡 ) =
50 C to 350 C
Cold Mass Fraction (µ)
=
0.3 to 0.8
i.e.
4.1 Effect of evaporator temperature on
optimum heat rejection pressure and
maximum cooling COP
(11)
The heat rejection pressure resulting in a
maximum 𝐶𝑂𝑃 is called as the optimum heat
rejection
Pressure 𝑃 , which can be determined with
𝑃 = 𝑃 (𝑡 , 𝑡 , 𝜂 , 𝜂 , 𝜀 , 𝜇, 𝑡 ) (12)
From equation (12), it is clear that optimum heat
rejection pressure in a transcritical N2O cycle
with vortex tube mainly depends on gas cooler
outlet temperature, evaporation temperature,
compressor and vortex tube nozzle efficiency,
desuperheater effectiveness as well as on cold
mass fraction and water temperature inlet to the
desuperheater.
Based on the above analysis, a simulation model
for transcritical N2O cycle with vortex tube
using EES software (Klein and Alvarado 2012)
is developed and optimum value of the heat
rejection pressure is calculated.
4. Results and Discussion
The following input parameters have been
considered for the analysis of transcritical cycle
with vortex tube based on maurer mode.
Refrigerant N2O has been used in the TCVT as
well as in TCEV for analysis.
Vortex tube nozzle efficiency (𝜂 )
=
0.75
Desuperheater effectiveness (𝜀 )
=
0.85
Gas cooler outlet temperature (𝑡 )
=
350 C to 600 C
Evaporator temperature (𝑡 )
=
-550 C to 50 C
Compressor isentropic efficiency (𝜂 )
=
0.80
Fig. 3 shows the variations of optimum heat
rejection pressure (𝑃 ) of TCVT and TCEV
with evaporation temperature (𝑡 ) for 𝑡 =450
C, µ = 0.5 and 𝑡
= 250 C. The optimum
pressure for both the cycles increases with
decrease of evaporator temperature for
refrigerant N2O. It is clear from the figure that
the 𝑃 is higher for TCEV compared to TCVT
for all considered values of evaporator
temperature. The value of optimum gas cooler
pressures for TCVT and TCEV varies from
10.93 to 9.78 MPa and from 11.85 to 9.86 MPa
respectively, for the considered evaporator
temperatures. It shows that evaporator
temperature has significant effect on the
optimum heat rejection pressure of both the
cycles.
12
Optimum heat rejection
pressure(MPa)
=0
TCE
V
11.5
11
10.5
10
9.5
-55
-45
-35
-25
-15
-5
5
Evaporator temperature (⁰ C)
Fig. 3. Variation of optimum discharge pressure
for TCVT and TCEV at different evaporator
temperatures
Fig. 4 shows the variation of COP values of the
two cycles with the evaporator temperature (𝑡 )
for the 𝑡 =450 C, µ = 0.5, 𝑡 = 250 C and at the
optimum heat rejection pressure (𝑃 ).The
maximum cooling COP for both the cycles
increases on increasing the values of evaporator
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2.5
2.3
2.1
1.9
1.7
1.5
1.3
1.1
0.9
0.7
0.5
Maximum COP
co
pb
temperature, the TCVT tends to show the
advantage in lowering the system pressure. The
value of gas cooler pressures for TCVT and
TCEV varies from 7.42 to 14.97 MPa and from
7.49 to 15.81 MPa respectively, for considered
gas cooler exit temperatures. It shows that gas
cooler exit temperature has great influence on
the optimum heat rejection pressure of both the
cycles.
Optimum heat rejection
pressure(MPa)
temperatures. It is also observed that maximum
cooling COP of TCVT is higher compared to
TCEV for all the values of evaporator
temperatures. The maximum cooling COP for
the TCVT and TCEV varies from 0.70 to 2.37
and from 0.61 to 2.27 respectively for
considered evaporator temperatures, whereas the
maximum cooling COP for TCVT is 14.41 %
and 4.36 % higher than TCEV corresponding to
evaporator temperatures of -550 C and 50 C
respectively. It can be concluded that the
application of vortex tube instead of expansion
valve is more beneficial at lower values of
evaporator temperature to reduce the optimum
heat rejection pressure and increase the
maximum cooling COP.
16.5
15.5
14.5
13.5
12.5
11.5
10.5
9.5
8.5
7.5
6.5
TC
EV
35
40
45
50
55
60
Gas cooler outlet temperature ( ⁰C)
-55
-45
-35
-25
-15
-5
5
Evaporator temperature (⁰ C)
Fig. 4. Variation of maximum cooling COP for
TCVT and TCEV at different evaporator
temperatures
4.2 Effect of gas cooler exit temperature on
optimum heat rejection pressure and
maximum cooling COP
Fig. 5 shows the variations of 𝑃
for TCVT
and TCEV with gas cooler exit temperature (𝑡 )
for 𝑡 = -200 C, µ = 0.5 and 𝑡 = 250 C. The
optimum pressure increases with the gas cooler
exit temperature for both TCVT and TCEV. The
value of 𝑃
for TCVT is lower compared to
TCEV at all the considered values of gas cooler
exit temperatures. It is observed that at low value
of gas cooler outlet temperature, both the cycles
have very close optimum heat rejection pressure,
whereas on increasing the gas cooler
Fig. 5. Variation of optimum heat rejection
pressure for TCVT and TCEV at different gas
cooler outlet temperatures
Fig. 6 shows the variation of COP values of the
two cycles with the gas cooler exit temperature
(𝑡 ) for the 𝑡 = -200 C, µ = 0.5, 𝑡 = 250 C and
at the optimum heat rejection pressure (P ). It
is observed that the cooling COP for both the
cycles decreases rapidly with the increase of gas
cooler outlet temperatures. The maximum
cooling COP of TCVT is higher compared to
TCEV for all the gas cooler outlet temperatures.
The maximum cooling COP for the TCVT and
TCEV varies from 1.84 to 0.94 and from 1.78 to
0.82 respectively for the considered gas cooler
outlet temperatures, whereas the maximum
cooling COP for TCVT is 2.97 % and 14.96 %
higher than TCEV corresponding to gas cooler
temperatures of 350 C and 600 C respectively. It
is concluded from the figures 3, 4, 5 & 6 that
lower values of gas cooler exit temperatures and
higher evaporator temperatures are the necessary
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conditions not only for the maximum COP but
also for lower values of P .
12.5
Maximum COP
1.8
co
pb
1.6
1.4
1.2
1
0.8
0.6
35
40
45
50
55
60
Optimum heat rejection Pressure (MPa)
2
11.5
10.5
9.5
𝑡 = -200 C, 𝑡 = 450 C, μ = 0.5,
𝑡 = 250C, 𝜀 =0.85, 𝜂𝑣 =0.75
8.5
7.5
Gas cooler outlet temperature ( ⁰C)
6.5
Fig. 6. Variation of maximum cooling COP for
TCVT and TCEV at different gas cooler outlet
temperatures
4.3 Effect of 𝛈𝐯 , 𝛈𝐜 , 𝛆𝐝𝐞 , 𝛍, 𝐭 𝐰𝐝 on optimum
heat rejection pressure
Figs. 7 and 8 shows the variation of optimum
heat rejection pressure (P ) with the vortex
tube nozzle efficiency ( 𝜂 ) and compressor
isentropic efficiency (𝜂 ) respectively for TCVT
at 𝑡 = -200 C, 𝑡 = 450 C.
0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
Compressor isentropic efficiency
Fig. 8. Optimum heat rejection pressure versus
the compressor isentropic efficiency
Figs. 9 and 10 shows the variation of optimum
heat rejection pressure (P ) with the
desuperheater effectiveness (𝜀 ) and cold mass
fraction (𝜇 ) respectively for TCVT at 𝑡 = -200
C, 𝑡 = 450 C.
Optimum heat rejection pressure
(MPa)
Optimum heat rejection Pressure (MPa)
12.5
12.5
11.5
11.5
10.5
10.5
9.5
𝑡 = -200 C, 𝑡 = 450 C, μ = 0.5,
𝑡 = 250C, 𝜂 =0.80, 𝜂 =0.75
9.5
𝑡 = -200 C, 𝑡 = 450 C, μ = 0.5,
𝑡 = 250C, 𝜂 =0.80, 𝜀 =0.85
=0.85
8.5
7.5
8.5
7.5
6.5
0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
Vortex tube nozzle efficiency
6.5
0.6
0.65
0.7
0.75
0.8
0.85
0.9
0.95
Desuperheater effectiveness
Fig. 7. Optimum heat rejection pressure versus
the vortex tube nozzle efficiency
Fig. 9. Optimum heat rejection pressure versus
the Desuperheater effectiveness
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From the Figs. 7, 8,9,10 and 11, it is concluded
that the effect of various parameters
(η , η , ε , μ, t ) are negligible on the
optimum heat rejection pressure of TCVT.
Optimum heat rejection pressure (MPa)
12.5
11.5
4.4 Correlation for optimal heat rejection
pressure
10.5
9.5
𝑡 = -200 C, 𝑡 = 450 C, 𝜂 =0.80,
𝑡 = 250C, 𝜀 =0.85, 𝜂𝑣 =0.75
8.5
7.5
6.5
0.3
0.4
0.5
0.6
0.7
0.8
Cold mass fraction
Fig. 10. Optimum heat rejection pressure versus
the cold mass fraction
Fig. 11 shows the variation of optimum heat
rejection pressure (P ) with the water inlet
temperature to desuperheater (𝑡 ) for TCVT
at 𝑡 = -200 C, 𝑡 = 450 C.
Optimum heat rejection pressure (MPa)
12.5
11.5
10.5
9.5
𝑡 = -200 C, 𝑡 = 450 C, μ = 0.5,
𝜂 =0.80, 𝜀 =0.85, 𝜂𝑣 =0.75
8.5
In engineering systems correlations are widely
employed to provide a quick guideline and
reasonable accurate results. As described from
Equation (12), the optimal heat rejection
pressure for TCVT can be correlated with gas
cooler
outlet
temperature,
evaporation
temperature, compressor and vortex tube nozzle
efficiency, desuperheater effectiveness, cold
mass fraction and water temperature inlet to the
desuperheater, whereas the results show that
optimum heat rejection pressure only depends
on evaporator and gas cooler exit temperatures.
The
effect
of
other
parameters
(η , η , ε , μ, t ) are negligible on optimum
gas cooler pressure. Therefore, the optimum heat
rejection pressure can be considered as a
function of the evaporator temperature and the
gas cooler outlet temperature. The simulation
results of the optimum heat rejection pressure
are shown at different evaporator and gas cooler
exit temperatures in Table 1. It is clear from the
table that the effect of gas cooler exit
temperature is significant on the 𝑃 compared
to evaporator temperature.
Table 1. Variation of P (MPa) for TCVT with
gas cooler temperature (t ) and evaporator
temperature (t )
tc
tₑ=5⁰
C
Optimum heat rejection pressures (MPa)
tₑ= -5⁰
tₑ=tₑ=tₑ=tₑ=15⁰ C
25⁰ C
35⁰ C
45⁰ C
C
tₑ= 55⁰ C
35
7.209
7.293
7.38
7.754
40
8.488
8.624
8.762
8.9
9.04
9.18
9.32
45
9.787
9.979
10.17
10.362
10.554
10.745
10.934
50
11.139
11.385
11.632
11.879
12.126
12.371
12.612
55
12.57
12.864
13.165
13.469
13.772
14.072
14.366
60
14.1
14.436
14.787
15.145
15.504
15.859
16.206
7.5
6.5
5
10
15
20
25
30
35
Inlet water temperature to desuperheater
(⁰ C)
Fig. 11. Optimum heat rejection pressure versus
the inlet water temperature to desuperheater
7.471
7.563
7.658
From the simulation results, a correlation has
been obtained to predict the optimal heat
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rejection pressure (in MPa) for transcritical N2O
refrigeration
cycle
with
vortex
tube
(R2=99.54%), as given in equation (13)
𝑃 = −1.0951 − 0.022𝑡 + 0.1847𝑡 +
0.00128𝑡
(13)
Where, R2 signifies the perfectness of data
fitting. This correlation is valid for evaporator
temperature (𝑡 ) of -550 C to 50 C and gas cooler
exit temperature (𝑡 ) of 350 C to 600 C.
Conclusions
In the present study, thermodynamic model of
TCVT and TCEV are analyzed for the effect of
heat rejection pressure on COP. Based on the
simulation results of the cycles, following
conclusions can be drawn.
(1) For a transcritical N2O refrigeration cycle
with expansion valve or vortex tube, there exists
an optimal heat rejection pressure that gives a
maximum COP.
(2) The TCVT has high COP and low optimum
pressure compared to TCEV at all the considered
evaporator and gas cooler temperatures.
(3) The analysis of TCVT reveals that the values
of the optimum heat rejection pressure mainly
depend on the evaporator and gas cooler exit
temperatures. The effects of other parameters
(compressor efficiency, vortex tube nozzle
efficiency, gas cooler outlet temperature,
evaporator temperature, cold mass fraction and
water inlet temperature to desuperheater) are
negligible.
(4) A correlation has been obtained for the
optimum heat rejection pressure in terms of
evaporator and gas cooler temperatures. This
correlation offer useful guidelines for system
development and performance optimization of a
transcritical N2O refrigeration cycle with vortex
tube.
References
1. Agrawal, N., Sarkar, J., Bhattacharyya, S.
(2011).“Thermodynamic analysis and
optimization of a novel two stage
transcritical N2O cycle” International
Journal of Refrigeration 34:991–999.
2. Aprea, C., Maiorino, A.,(2009) “Heat
rejection pressure optimization for a carbon
dioxide split system: an experimental study”
Appl. Energy 86 : 2373-2380.
3. Cecchinato, L., Corradi, M., Minetto,
S.(2010) “A critical approach to the
determination of optimal heat rejection
pressure in transcritical systems”Appl.
Therm. Eng.30 : 1812-1823.
4. Chen, Y., Gu, J.,(2005) “The optimum high
pressure for CO2 transcritical refrigeration
systems with internal heat exchangers” Int.
J. Refrig. 28 :1238-1249.
5. Christensen, K.G., Heiredal, M., Kauffeld,
M., Schneider, P. (2001).“Energy savings in
refrigeration by means of a new expansion
device.”
Report
of
Energy
researchprogramme, Journal no. 1223/99–
0006.
6. Jain, G., Arora, A.,Gupta, S., (2017).
“Performance analysis of a transcritical N2O
refrigeration
cycle
with
vortex
tube”International journal of ambient
energy”.
http://dx.doi.org/
10.1080/
01430750.2017.1399449
7. Kauf, F.,(1999) “ Determination of the
optimum high pressure for transcritical CO2
refrigeration cycles” Int. J. Therm. Sci. 38:
325-330
8. Klein, S.A., Alvarado, F. (2012).
Engineering Equation Solver, Version
9.224, F-chart Software, Middleton,WI.
9. Kruse, H., Rüssmann, H. (2006).“The
natural fluid nitrous oxide—an Option as
substitute for low temperature synthetic
refrigerants.”International
Journal
of
Refrigeration 29: 799-806.
10. Li, D., Baek, J.S., Groll, E.A. and Lawless,
P.B. (2000) ‘Thermodynamic analysis of
vortex
11. tube and work output expansion devices for
the transcritical carbon dioxide cycle’,
Fourth
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23,
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12. IIR-Gustav Lorentzen Conference on
Natural Working Fluids at Purdue, Purdue
University,
13. USA, pp.433–440.
14. Liu, Y., Jin, G. (2012).“Vortex tube
expansion two-stage transcritical CO2
refrigeration cycle”. Advanced Materials
Research 516-517: 1219-1223.
15. Maurer, T. (1999). Patent DE 197 48 083
A1, Entspannungseinrichtung.
16. Sarkar, J. (2009).“Cycle parameter
optimization of vortex tube expansion
transcritical CO2 system”. International
Journal of Thermal Sciences 48: 1823-1828.
17. Sarkar,
J.,
Bhattacharyya,
S.
(2010).“Thermodynamic analyses and
optimization of a transcritical N2O
refrigeration cycle.”International Journal of
Refrigeration 33:33–40.
18. Xie, Y.B., Cui, K.K. , Wang, Z.C. , Liu, J.L.
(2011).“CO2 trans-critical two stage
compression refrigeration cycle with vortex
tube.” Applied Mechanics and Materials 5254: 255-260.
19. Zhang, X. , Wang, F., Fan, X., Wei, X.,
Wang, F. (2013) “Determination of the
optimum heat rejection pressure in
transcritical
cycles
working
with
R744/R290 mixture” Appl. Therm. Eng. 54
: 176-184.
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Impact of Renewable Energy Generation on Bidding Strategy
a
Md Irfan Ahmed a, Deepti Bhatia b and Aditya Sharma c
Career Point University, Electrical Engineering Department, Kota, Rajasthan, India
Corresponding Author: irfannitp.ahmed@gmail.com , deeptib442@gmail.com
Abstract
Renewable energy resources (RER) are the fastest growing energy resources in the world. RER exist
over wide geographical areas, in contrast to other energy sources, which are concentrated in a limited
number of countries. National renewable energy markets (REM) are projected to continue to grow
strongly in the coming decade and beyond. Due to need of such a source we need a well- managed
alternative which is abundant and easy to access. Most of the renewable energy resources had been
installed in the distribution systems as distributed generation. The change in the generation mix from
conventional electricity sources to renewables has important implications for bidding behaviour and
may have an impact on prices. The principle objective of this paper is to determine the role played by
expected renewable energy production, together with other relevant factors, in explaining the dayahead market price. It is suggested that the solar and wind power forecasts are a new key determinant
for supply market participants when bidding in the day-ahead market. We also provide a conservative
quantification of the effect of such trading strategies on marginal prices at an hourly level for a specific
year in the sample.
Keywords: - Renewable energy resources (RER), Renewable energy markets (REM), Competitive
electricity market (CEM), Bidding strategy (BS)
1. INTRODUCTION
fight climate change has been the creation of
Nowadays Electricity Price forecasting has
carbon emission markets [1].
been a vital and essential issue in every nation.
1.1 Indian Installed Capacity in 2017
Because of deregulation, the price for
electricity has come to be determined by
competitive bidding by producers and
consumers in the wholesale day-ahead market,
where an auction system is generally followed.
The electricity supply function is discontinuous
and increases with the level of demand [4]. The
resulting price from the auction, the so-called
marginal price, corresponds to the highest price
offered by the supply side from those accepted
to satisfy demand. The offered prices to sell
electricity will, in turn, depend on production
costs and these significantly differ among the
generation technologies. Therefore, the
generation mix of a specific market area,
among other factors, will likely condition the
resulting marginal prices and the success of a
given market design. Due to greater climate
awareness, the inclusion of renewable
production in the electricity system is a goal in
Table 1: All India Installed Capacity (In MW)
most countries. Apart from the promotion of
2017
renewable generation, another measure taken to
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In the Indian case, the development and
integration of renewable electricity production
in the electricity market has been a target for
the regulator over the last decade. Tables 1
show the annual figures for installed power
capacity and electrical energy in India per
generation technology in 2017.
2. BIDDING STRATEGY
In most of the country’s Electricity market is
planned as a day-ahead market where, the
electricity energy transactions are cleared for
each hour of the next day. In day-ahead market,
demand is estimated for each trading interval,
example one-hour period, twenty-four hours
ahead and offers and bids are received from the
market participants.
The changes from regulation to competition in
Electrical industries around the world have led
to the improvement of markets for Electricity.
Day-ahead electricity markets are emerging as
an important medium through which power is
allocated in many de-regulated environments. A
day-ahead electricity market is a short-term
hedge market that operates a day in advance of
the actual physical delivery of power. In these
environments, the generation decisions for the
next day are in most cases the result of a double
(two-sided) auction where producing (selling)
and consuming (buying) agents submit a set of
price-quantity curves (bids). The bids must be
submitted by a deadline on the day before
actual delivery of power. A clearing price based
on the submitted bids is determined by the ISO
(Independent System Operator) or market
making agent and all subsequent trades are
settled at this price [2].
2.1 Factors Affecting the Price of Electricity
1. Climate conditions
2. Constraints
3. Communication traffic
4. Fuel costs
5. Unit cost productions
6. Bidding strategies
7. Demand and supply Management
8. Power shortage
9. Outages of generation power plants
10. Market Policy
3. REM IN BIDDING STRATEGY
One advantage of the Indian auction format
is that it is more technology-neutral and thus
provides another way to promote robust
competition in REM.
The electricity market is structured to
guarantee matching between the offers from
generators and the bids from consumers at
each node of the power network according to
an economic merit order [1]. To perform this
task, the exchanges starts one day ahead on
the basis of daily energy demand forecasting
and then successive market sections refine
the offers with the aim of both satisfying the
balancing conditions and of preserving the
power quality and the security of energy
supply.
4. RENEWABLE ENERGY IMPACT ON
BS
The auction provides a unique opportunity to
participate in the new competitive wholesale
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electricity market and retain the traditional
opportunity of selling to the utility under a
long-term purchase power contract [3].
Increase in consumer choice and their
participation in short and long-term demand
management,
as
well
as
growing
responsibility to secure their own energy.
Models for Power Producers, Springer-Verlag
Berlin Heidelberg, 41-59, Doi 10.1007/978-3642-23193-3_2
[4] Cristina Ballester and Dolores Furió, 2017.
Impact of Wind Electricity Forecasts on
Bidding Strategies, International Journal of
Sustainable Energy, 1-17, doi:10.3390/
su9081318
6. CONCLUSION
The use of renewable energy sources is creating
a new energy market where it is of the utmost
importance to be in condition to anticipate
trends and needs from users and producers to
reduce inefficiencies in energy management
and optimize production. In the CEM every
participant wants to enhance its profit by using
information announced by market operator. The
participation of RES in the Indian electricity
market not only led to a decrease in equilibrium
prices, but also caused a change in combined
cycle bidding strategy in the spot market. Such
a decrease in prices forced combined cycle
producers to change their bids, so that they
could afford their production costs when they
are matched in the pool. We observe that (i)
combined cycle plants bid now at lower prices
and that (ii) their participation in adjustment
markets has increased. The question now is if
the market price reductions entailed by RES are
enough to pay for the increasing costs of the
adjustment markets.
REFERENCES
[1] I.L.R. Gomes, H.M.I. Pousinho, R. Melíco,
V.M.F.
Mendes,
2016.
Bidding
and
Optimization Strategies for Wind-PV Systems
in Electricity Markets Assisted by CPS. Energy
Procedia,
106,
111-121.
doi:
10.1016/j.egypro.2016.12.109.
[2] M. Begović, A. Pregelj, A. Rohatgi and D.
Novosel, 2001. Impact of Renewable
Distributed Generation on Power Systems,
Proceedings of the 34th Hawaii International
Conference on System Sciences, 1-10.
[3] Roy H. Kwon and Daniel Frances, 2012.
Optimization-Based Bidding in Day-Ahead
Electricity Auction Markets: A Review of
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 2223, 2017 at GEC Banswara, www.apgres.in
Review of Different Energy Resources
Sandeep Kumara and Emarti Kumarib
a
Department of Computer Engineering, St. Wilfred’s Institute of Engineering & Technology, Ajmer, Rajasthan
b
Department of Mechanical Engineering, M.B.M. Engineering College, Jodhpur, Rajasthan
Abstract
The demand of Electricity is increasing day by day on the earth, because the global population is
increasing continuously. At present, approximately the global population is nearly eight billion
people, but one third of the population do not have electricity. Thus, we are looking for alternative
energy resources for example renewable energy, fossil fuel energy, nuclear energy, hydro energy, etc.
The objective of this research paper is to study the various aspects for instance power consumption
rate and power production rate of energy.
Keywords: Renewable Energy; Fossil Fuel Energy; Nuclear Energy.
1. Introduction
In now a day the electricity consumption is
growing faster than energy production. It is
expected that during the period 2000 to 2040
in all fields and regions the annual demand will
increase by 2.3 % per year was reviewed by
researchers [1 – 3]. Hence, further research and
review is necessary to estimate the exact
demand and production of energy through
various energy resources.
There are many forms of energy resources
available for example fossil energy, nuclear
energy, renewable energy sources. Mostly
countries are using fossil energy as their
primary energy sources and nuclear energy as
secondary to meet their requirement from day
by day, but these sources are not satisfactory
and appropriate source of energy and not better
for environment. Because fossil and nuclear
energy resources are limited. Therefore, for
securing the future of coming generations we
have to switch on environmental friendly
energy resources. This leads to the usage of
renewable sources in many parts of the world.
Renewable energy is easily available in
abundance in most parts of the world and is the
most readily available free source of energy.
Renewable energy is to be the most appropriate
green energy and is environmental friendly.
The amount of solar energy incident on the
earth's surface is approximately 1.53 × 1018
kW/year, which is about 10,000 times the
current annual energy consumption of the
entire earth.
2. Energy
Energy is the extensive property that can
be transferred from one form to another form
for example heat to chemical reactions and
chemical reactions to thermal energy similarly
thermal energy to mechanical energy and
mechanical energy to electrical energy or vice
versa. An energy resource can produce heat,
move objects and produce electricity. The
Common forms
of
energy are
kinetic
energy of a moving object and the potential
energy stored by an object's position in a
force field gravitational, electric or magnetic,
the elastic energy stored by stretching solid
objects, the chemical energy released when a
fuel burns, the radiant energy carried by light,
and
the thermal
energy due
to
an
object's temperature. The people are using
several energy’s for: residential, commercial,
transportation, and industries.
Human energy consumption has grown
regularly throughout human and earth
history. Living organisms require available
energy to stay alive, such as the energy from
food. Early humans had modest energy
requirements, mostly food and fuel for fires to
cook and keep warm. In today society humans
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 2223, 2017 at GEC Banswara, www.apgres.in
consume as much as 200 times as much energy
per person as early humans. Most of the
energy we use today come from fossil
fuels. But fossils fuels have a disadvantage in
that they are non-renewable on a human time
scale, and also causes other potentially harmful
effects on the environment.
Human civilization requires energy to
function, which it gets from energy
resources such as fossil fuels, nuclear fuel
and renewable energy. The processes of
Earth climate and ecosystem are driven by the
radiant energy Earth receives from the sun and
the geothermal energy contained within the
earth. Between 2015 and 2040, world energy
consumption increases by 30% in the IEO
(international energy organization) 2017.
2.1 Energy Resources
Figure 1. Various available energy resources’
2.1.1
Fossil fuel production and
consumption
Fossil fuels continuously have a dominant role
in global energy systems. Fossil energy was a
fundamental driver of the industrial revolution,
and the technological, social, economic and
development progress which has followed.
Energy has played a strongly positive role in
global development.
However, fossil fuels also have negative
impacts, being the dominant source of local air
pollution and emitter of CO2, CO, NO2 and
other greenhouse gases. The world must
therefore balance the role of energy in social
and economic development with the need to
decarbonise, reduce our reliance on fossil
fuels, and transition towards lower-carbon
energy sources. Fossil energy sources
available in the form of Coal, Natural Gas, Oil,
Sustainability, are expressed in Figure 1. Fossil
energy resources are presented by yellow
colour because it is reducing continuously due
to extraction of resources day by day.
The 20th century saw a large diversification of
fossil energy consumption, with coal declining
from 96% of total production in 1900 to less
than 30% in 2000 and 20% in 2040. Today,
crude oil is the largest energy source,
accounting around 40% of fossil energy,
followed by coal and natural gas at 33% and
28% respectively.
2.1.2 Nuclear energy
Nuclear energy is energy in the core of an
atom. Everything around you are made up of
tiny objects called atoms. Atoms are tiny
particles that make up every object in the
universe.
Most of the mass of each atom is concentrated
in the centre and the rest of the mass is in the
cloud of electrons surrounding the nucleus.
Protons and neutrons are subatomic particles
that comprise the nucleus. Under certain
circumstances, the nucleus of a very large atom
can split in two. In this process, a certain
amount of the large atom’s mass is converted
to pure energy following Einstein’s famous
formula E = MV2, where M is the small amount
of mass and C is the speed of light. Nuclear
energy can be used to make electricity. It can
be released from atom in two ways as shown in
Figure 1. Nuclear fusion and nuclear fission, in
nuclear fission atoms are split apart to form
smaller atoms releasing energy and in nuclear
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2.1.3 Renewable energy resources
Renewable energy is energy that is collected
from natural resources which are naturally
replenished on a human timescale such as sun,
wind, rain, tide, waves, hydropower, biomass
and geothermal heat. Typically, renewable
energy resources have much lower greenhouse
gas and other emissions associated with use.
The renewable energy resources are cleaner
and offer a sustainable supply of energy and
nature friendly. As of 2015 worldwide, more
than half of all new electricity capacity
installed was renewable. Renewable energy
resources have much lower greenhouse gas
and other emissions associated with use. Thus,
world is switching to renewable energy
resources frequently comparatively primary,
secondary energy resources. Various (3.1 Solar
energy. 3.2 Wind power. 3.3 Wave and tidal
power. 3.4 Geothermal. 3.5 Biomass. 3.6
Hydropower) available renewable energy
resources are shown in Figure 1. With green
colour because these resources are healthy for
human’s, animals and surrounding’s.
2.2 Energy Consumption
Continent wise energy consumption is given in
the Table 1. from 2006 to 2016. In the Table
also elaborated growth rate per annum of
energy consumption. It is observed from Table
that due to increasing the use of renewable
energy fossil energy consumption is decreases
in Europe & Eurasia and South & Cent.
America by 0.4 % and 1 % respectively. Here,
also observed the average growth rate per
annum reduction in year 2016 as compared to
year 2006 to 2015 as shown in Figure 2.
Table 1. Different continent energy
consumption
Year
Africa
North
America
Europe
&
Eurasia
Asia
Pacific
3924.3
South &
Cent.
Middle
America
East
Energy consumption (million tonne oil equivalent)
2006
334.8
567.8
592.2
2824.1
3023.5
2007
347.9
593.9
625.6
2866.5
3017.7
4175
2008
369.5
613.2
667.6
2819.2
3022.2
4292.1
2009
373.4
606
690.3
2689.7
2839.8
4402.2
2010
388.9
641.7
734.2
2777.8
2952.6
4674.7
2011
388
665.4
750.3
2778.6
2937.9
4935.1
2012
402.9
680.9
780.8
2724.3
2936.3
5095.5
2013
415.4
696.7
812.4
2795.9
2900.6
5245
2014
427.9
704.1
840
2821.2
2838.3
5357.2
2015
433.5
710.4
874.6
2792.4
2846.6
5447.4
2016
440.1
705.3
895.1
2788.9
2867.1
5579.7
Growth rate per annum
2016
20062015
1.20%
-1.00%
2.10%
-0.40%
0.40%
2.10%
2.80%
2.80%
4.50%
-0.20%
-0.40%
3.90%
7000
Consumption (Mil. tonne oil equ.)
fusion energy is released when atoms are
combined or fused together to form a larger
atom. Nuclear energy is represented by red
colour, because the emission rays due to
nuclear fusion and nuclear fission is very
dangerous for humans, animals and
surrounding. Thus nuclear energy is not
environmental friendly. But, nuclear energy is
great resources of energy as given here:
The first commercial nuclear power
stations started in the 1950s.
There are over 450 commercial nuclear
power reactors operable in 32 countries, with
over 396,000 MW of total capacity and 70
more reactors are under construction.
Nuclear plant provides over 16% of the
world's electricity as continuous reliable power
to meet base-load demand without CO2
emissions.
55 countries operate a total of about
250 research reactors, and a further 180
nuclear reactors.
6000
Africa
S. & Cent. America
Middle East
North America
Europe & Eurasia
Asia Pacific
5000
4000
3000
2000
1000
0
2006
2008
2010
2012
2014
2016
Year
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Consumption (Mil. tonne oil equ.)
7000
6000
Africa
S. & Cent. America
Middle East
North America
Europe & Eurasia
Asia Pacific
5000
4000
3000
2000
1000
0
2006
2008
2010
2012
2014
2016
Year
Figure 2. Energy consumption per annum
3. Summary
In this communication authors have reviewed
the consumption of various energy resources
for example fossil energy, nuclear energy and
renewable energies in last twelve years by
world wise. Here, also noticed the value of
renewable energy for instance: solar energy,
biomass, wave and tidal energy, wind energy
and hydro energy, etc. from environment point
of view as well as future perspective wise.
References
1. Sumit, W. & Walke, P.V. (2017). Review
on wind- solar hybrid system,
International Journal of Research in
Science & Engineering, 3 (2), 71-76.
2. Anwarul, H.M. & Dubey, R.R. (2014).
Solar Energy – An Eternal Renewable
Power Resource, International Journal of
Advanced Research in Electrical,
Electronics
and
Instrumentation
Engineering, 3 (2), 7344 – 7351.
3. Christenseen, E. (2015). Electricity
Generation, 173.
4. Schiffer, H.W. (2016). World Energy
Resources. World Energy Concil.
5. Dudley, B. (2017). BP Statistical Review
of World Energy.
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A Review of CFD Methodology used for Solar Devices
Himanshu Pandya
Dept. of Mechanical Engg, Techno India NJR Institute of Technology, Udaipur, Rajasthan, India
Corresponding Author Email: erhimanshupandya@gmail.com
Abstract
Tremendous need of renewable energy development is very much felt in every part of the globe and
sun energy is a prime source of renewable energy, many different techniques and devices are created
to harness this vast amount of clean energy source as an alternative to the fossil fuels. Experiments
on the physical models and prototypes has been done to create a higher efficiency device but they are
time-consuming and costly processes and with the development in the field of computer, scientist and
inventors are equipped with the powerful technique of numerical or computational fluid dynamics
(CFD) simulation. With the help of numerical or CFD simulation various parameters and effects are
check prior to building a physical system with a good accuracy. This article discusses the
computational approach used by various researchers in developing various solar systems such as solar
water heater, solar air heater and solar still. And also, about the advantages and limitations of the
computational approach. In this review it is found out that CFD results are validates with the
experimental results and various parametric study can be done more efficiently.CFD is a powerful
tool of the analysis of the physical problem.
Keywords: Solar energy, solar water heater, solar air heater, solar still, CFD.
1. Introduction
The sun is a major source of renewable free
energy (i.e. solar energy) for our planet Earth.
With the modernization new technologies are
being employed to generate energy from
harvested solar energy. These approaches have
already been proven and are widely practiced
throughout the globe as renewable alternatives
to conventional nonrenewable energy sources
[1]. Also use of solar energy for domestic and
industrial heating purposes has also increased.
With the increase in demand in solar energy
due to the following reasons: 1.
Solar energy is free and available for
most of the year for the major part of the globe.
2.
It is pollution free and also helps in
carbon reduction in the world [2].
3.
It is Available in abundance such that it
can full fill all the world demand if its
harvesting and supplying technologies are
readily available [3].
It’s now a great challenge for engineers,
researchers, scientist and inventors to create
such devices which can easily and efficiently
harness, store, and utilize this immense source
of pollution free energy. This required great
amount to research has to be done, which is
also happing in more advance ways then it was
before. The analysis of solar devices was
carried out in the literature using three
approaches as stated below
1. Experimental
2. Theoretical (mathematical)
3. Computational approach.
In this paper, main objective is to highlight the
latest work done in Computational approach
for solar devices with brief introduction and
comparison with Experimental approach.
2. Methods or approaches for solar devices
analysis
A solar device involves the physics of fluid and
heat flow. For analyzing the solar devices its
thermal and hydraulic performance has to be
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 2223, 2017 at GEC Banswara, www.apgres.in
predicted. To evaluate its thermal and
hydraulic performance, solar devices can be
analyzed using experimental, theoretical or
analytical and numerical or computational
approach (i.e. CFD).
2.1 Experimental approach
In experimental approach, a prototype (actual
dimensions or scaled model) of a solar device
is manufactured and on it experiments are
performed. Thermal and hydraulic parameters
like temperature, pressure, flow etc are
measured to evaluate the performance of the
device.
Various factors like cost of
manufacturing the device, time required for
research,
experimental
facility
and
measurement devices, apart from these human
error, measurement error and atmospheric
condition play a critical role in the accuracy of
the research data from the experimental
method [4].
2.2 Analytical approach
In theoretical or analytical approach,
mathematical equations which are generally
partial differential equations represent the
governing equation of the physics are used.
These are solved using various mathematical
analytical approach but the solving a higher
order complex equation is a difficult task. To
solve these complex equations researcher, use
various assumption such that equation
becomes easy to solve and the results obtained
from it matches with the experimental results
[5].
2.3 Computational approach
Computational approach is the latest
approaches for analysis, it uses numerical
solutions to the mathematical governing
equations with the help of powerful
computational
software
like
ANSYS
FLUENT, ANSYS CFX, CFD ++, Open
FOAM, GASP CFL 3D, TYPHON etc. In CFD
governing equations which are in the form of
integrals or the partial derivatives are
converted into discretized algebraic which
gives the solutions at discrete points. The main
three elements of every CFD codes are (i) a
pre- processor, (ii) a solver and (iii) a postprocessor
2.3.1. Pre-processing
In Pre-processing a 3D model of the object of
interest is created, and then this domain is
divided into number of smaller domain which
is known as grid generation or meshing.
Smaller element thus formed from meshing is
also known as cell and solution to the
governing equation are defined at nodes inside
each cell. As the number of cell increases
accuracy and cost of computational also
increases. Fluid properties and boundary
conditions are also stated in this step.
2.3.2 Solver
Governing equations are converted into
discrete system of algebraic equation using
suitable discretization procedure such as finite
difference method (FDM), finite element
method (FEM) or finite volume method
(FVM). In CFD codes FVM is mostly
preferred. Now these algebraic equations are
solved by an iterative method.
2.3.3 Post-processing
Post processing is use to examine the results, it
includes the visualization tools like contour
plots, vector plots, line and shaded plots, 2D
and 3D surface plots etc. and also numerical
reporting tools to examine various properties
like pressure, temperature, heat transfer
coefficient etc. of the system.
2.3.4 Validation
Table 1 Difference between experimental and
computational approach [6]
Experimental
Computational
Experiments
are
expensive to setup
These
are
time
consuming
Modification in setup is
difficult
Large
number
of
measuring instruments
required
Except initial software
cost, it is less costly
Less time consuming as
compare to experimental
Modification can be done
easily
Various
tools
are
available for calculating
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 2223, 2017 at GEC Banswara, www.apgres.in
Not limited to
complexity
of
problem
the
the
Limited number of
experimental data and at
limited time period
But gives real solution to
the problem
Availability
of
mathematical model sets
limit to the complex
problem
No such limitation of time
and space
Solution
accuracy
depends
upon
approximation
taken
during simulations
CFD solution of physical problem must be
validated with the experimental data to ensure
sufficient accurate description of the reality. In
many conditions no experimental data is
available; simulation process is carried out
with scale model for which experimental
results are available and then it is extended for
full scale model. Table 1 shows the difference
between experimental and computational
3. CFD methodology for solar devices
Bouhal et al. [7] have simulate two different
configuration of solar water heater’s storage
tank, one with the charge inlet and outlet in
horizontal direction (Configuration A) and
other having charge inlet and outlet in vertical
direction (Configuration B). In both the
configurations effect of flat plate inside the
tank as an obstacle to flow has been studied.
The flat plate is located horizontally in
different position in Configuration A and tilted
in various angle in Configuration B has been
simulated. The following conclusions were
drawn from their analysis: (1) CFD framework
has been done to evaluate thermal stratification
in vertical solar storage. (2) CFD codes are
validated with the experimental work done
before and a good agreement between them
has been found out. (3) The optimum case for
configuration A is when two horizontal plates
located at the Middle and Top in the tank. (4)
The optimum case for configuration B is when
plate is tilted 30°.
D.G. Gunjo et al. [8] have carried out
experiment and CFD analysis on the novel
type solar collector.CFD analysis of a single
bent riser tube attached to an absorber plate has
been done.
Their results reveal that: (1) CFD results are
validated with the experimental setup with low
deviation in the results. (2) For the investigated
solar collector with 60°C outlet water
temperature maximum thermal efficiency of
71% was obtained. (3) The simulation model
of the collector gives the outlet water
temperature, energy efficiency, absorber plate
temperature, and overall heat loss coefficient
with maximum error of 9%.
Both experiment and CFD analysis have been
carried out by Facao [9] to analyze the flow
distribution in solar collectors which is done
first time on the varying diameter solar
collector which are generally of constant
diameter. The main outcomes were: (1) There
is good agreement between CFD and
experimental results. (2) The header manifold
dimension of the outlet must be greater than
that of the inlet for better results.
ANSYS CFX was used by H.N. Panchal et al.
[10] to simulate the solar still model and
validate with the experimental setup. Their
results show that: (1) the average deviations
from CFD and experimental values for
production rate and water temperature are
6.0% and 10.25% respectively. (2) ANSYS
CFX is very powerful tool for design,
difficulty removal in solar still construction
and parameter analysis.
A computational analysis using ANSYS
FLUENT has been carried out by Khare et al.
[11] on simple solar still The main
observations from their study were: (1)
Simulation results were found to be in good
agreement with the experimental data within
the scope of their study. (2) Thermal efficiency
of the Solar Still is higher from 16:00 to 17:00
hrs. (3) Rubber is found to be one of the best
basin materials to improve absorption, storage,
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 2223, 2017 at GEC Banswara, www.apgres.in
and evaporation effects. (4) The Solar Still for
low water depth has more productivity.
Panchal et al. [12 ] performed a CFD
simulation and experimental analysis of
hemispherical solar still. The conclusions
drawn from their analysis were: (1) Distillate
water errors of 12 % while comparing with
actual experimental results. (2) Also, good
agreement with experimental data and average
error of water temperature is 8 %.
Jin et al. [13] Conducted 3D numerical
investigation of solar air heater having multi
V-shaped ribs on the absorber plate to study
the effect of heat transfer and fluid flow
characteristics. The major findings of theirs
tudies are listed here – (1) Multi V-shaped ribs
promote the fluid mixing between the colder
upper channel fluid and the warmer nearbottom-wall fluid by generating the stream
wise helical vortex flows. (2) Heat transfer was
greatly improved when compared to a smooth
wall channel. (3) The maximum values of both
the thermo hydraulic performance parameter
and average Nusselt number was for Angle of
attack of 45°, and an angle of attack of 60°
gave the highest value of the friction factor.
Yadav et al. [14] simulated a 3D computational
domain of roughened solar air heater with nonuniform mesh using V-shaped perforated
blocks as artificial roughness on the absorber
plate. Their study revealed following
conclusions: (1) for perforated V-shaped
blockages average enchantment in the Nusselt
number was found to be 33% higher than solid
blockages. (2) Friction factor blockages were
decreased by 32% of the value as observed in
solid blockages.
Singh et al. [15] investigates a CFD using 3D
computational domain of solar air heater to
study effect of non-uniform and uniform cross
section transverse rib on the friction factor and
Nusselt number of roughened solar air heater.
The major findings of the study were: (1) For
Reynolds number above 7000 the Nusselt
number for non-uniform cross-section saw-
tooth rib was more than uniform cross-section
ribs. (2) For the range of Reynolds number
investigated the Nusselt number for
trapezoidal rib was found to be highest
followed by square rib and circular rib. (3)
CFD results also found in good agreement with
the experimental data.
4.Conclusion
The conclusions which can be derived from
this article are presented here:
(1)CFD is a powerful tool for the analysis of
the physical problems
(2)With the advance in technology and
research more number of analysis with CFD
are happing all around the world
(3)With number of advantages over
experimental approach many researchers
are performing CFD analysis
(4)With growing need of free and clean energy
CFD analysis in the field of solar energy is
a vast field and lot many work has to be
done.
(5)Still there is limited number of research
available on CFD analysis on solar devices
(6) For obtaining results with greater accuracy
in CFD; mathematical model, boundary
conditions, and assumption made during
simulation play a great role
(7)But for the final validation of the CFD
results experimental data are required.
References
1.Solar energy: Potential and future prospects
Ehsanul Kabira, Pawan Kumarb, Sandeep
Kumarc, Adedeji A. Adelodund, Ki-Hyun
Kime,
Renewable
and
Sustainable
EnergyReviews 82 (2018) 894–900
2. International Energy Agency. 2D S-hiRen
Scenario, Energy Technology Perspectives;
2012.
3. Blaschke T, Biberacher M, Gadocha S,
Schardinger
I.
Energy
landscapes:
meetingenergy
demands
and
human
aspirations. Biomass- Bioenergy 2013;55:3–
16.
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 2223, 2017 at GEC Banswara, www.apgres.in
4. Gawande V B, Dhoble A S ,Zodpe D B.
Effect of roughness geometries on heat transfer
enhancement in solar thermal systems—a
review
.Renew
Sustain
Energy
Rev2014;32:347–78.
5. Shamardan M M,Norouzi M,Kayhani M
H,Delouei A A. An exact analytical solution
for convective heat transfer in rectangular
ducts .Zhejiang Univ-SciA 2012; 13(10):768–
81
6. A review of CFD methodology used in
literature for predicting thermo-hydraulic
performance of a roughened solar air heater
Vipin B.Gawande , A.S.Dhoble , D.B.Zodpe ,
Sunil Chamoli Renewable and Sustainable
Energy Reviews 54 (2016) 550–605.
7. Numerical modeling and optimization of
thermal stratification in solar hot water storage
tanks for domestic applications: CFD study T.
Bouhala, S. Fertahib, Y. Agrouaza,, T. El
Rhafiki, T. Kousksou, A. Jamil ,Solar Energy
157 (2017) 441–455.
8. Exergy and energy analysis of a novel type
solar collector under steady state condition:
Experimental and CFD analysis Dawit Gudeta
Gunjo, Pinakeswar Mahanta, Puthuveettil
Sreedharan Robi* Renewable Energy 114
(2017) 655-669.
9. J. Facao, Optimization of flow distribution
in flat plate solar thermal collectors with riser
and header arrangements, Sol. Energy 120
(2015) 104-112.
10. Hitesh N Panchal, P. K. (2011). Modelling
and verification of single slope solar still using
ANSYS CFX. International Journal of Energy
and Environment, 2(6), 985-998.
11. Modeling and Performance Enhancement
of Single Slope Solar Still using CFD Vaibhav
Rai Kharea, Abhay Pratap Singhb*, Hemant
Kumarc, Rahul Khatrib Energy Procedia 109
(2017) 447 – 455.
12. Experimental and ANSYS CFD simulation
analysis of hemispherical solar still, Hitesh N
Panchal, P.K. Shah. International Journal of
Renewable Energy, Vol. 8, No. 1, January –
June 2013
13.Dongxu Jin, Manman Zhang, Ping Wang,
Shasha Xu. Numerical investigation of heat
transfer and fluid flow in a solar air heater duct
with multi V-shaped ribs on the absorber plate.
Energy 2015;89:178–90.
14.Yadav A S, Samant T S, Varshney L. A
CFD based analysis of solar air heater having
V-shaped perforated blocks on absorber plate.
Int Res J Eng Technol 2015;2(2):822–9.
15.Singh S, Singh B, Hans V S, Gill R S.CFD
(computational fluid dynamics) investigation
on Nusselt number and friction factor of solar
air heater duct roughened with non-uniform
cross-section transverse rib. Energy 2015;
84:509–17.
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23,
2017 at GEC Banswara, www.apgres.in
Impact of RES in Distribution Systems
Shubham Verma, Devendra Goyal and Pallavi Soni
Career Point University, Electrical Engineering Department, Kota, Rajasthan, India
Corresponding Author: vermashubham669@gmail.com, devagoyal87@gmail.com
Abstract
Renewable energy sources (RES) is defined as energy that comes from resources which are naturally
replenished on a human time scale such as Wind, sunlight, rain, tides, wave and etc. The high penetration
of renewable generations in the distribution system (DS) has introduced more uncertainties and technical
challenges in the operation of the grid-like voltage variation, degraded protection, altered transient
stability, two-way power flow, and increased fault level. The reverse power flow due to high penetration
of renewable generation may result to voltage rise which distribution network operators may not be able
to control effectively. This paper impacts the renewable generations such as solar photovoltaic (PV) and
wind energy on distribution system with voltage control strategies. The work shows that the application
of smart grid technologies such as demand side integration and energy storage mitigate voltage variation
problems with minimum network reinforcement.
Keywords: - Renewable Energy Sources (RES), Distribution system (DS), photovoltaic (PV),
Renewable Generation (RG)
1. INTRODUCTION
DS are undergoing a radical transformation, due
to several factors which contribute to the
evolution of distribution networks into the new
concept of smart grid but also greatly influence
the grid planning and operation. More
specifically, the new distribution grid will be
characterized by
(i) A massive penetration of dispersed
generation units,
(ii) The adoption of energy storage technologies
for providing services to the grid,
(iii) The active participation of end users to grid
operation, and
(iv) The use of information/communication
technologies which enables the information
exchange between all the grid resources. [1].
In recent years, the number of renewable
generation units connected to distribution
networks has continued to grow, and projections
are that this process will continue in the future.
The reason for this trend is to be found in the
increased interest in energy saving and reduction
of environmental impact. However, these
renewable generation units pose many
challenges to grid operators due not only to the
variability of their energy sources but also to
their integration into the distribution network.
2. BENEFITS OF DISTRIBUTED ENERGY
STORAGE SYSTEM
Storage of off-peak PV/wind energy
Power smoothing for large solar arrays
Peak-load deduction (peak shaving) at
substation
Distribution and transmission feeder
reliability improvement
Customer feeder load management
Ancillary services (frequent regulation,
black start capability).
2.1 Energy Scenario in India
Figure 1: India Energy Scenario
5th largest power generation portfolio.
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5th largest wind energy producer.
20,000 MW of solar power by 2022.
3. ADVANTAGES OF RES
One major advantage with the use of
renewable energy is that as it is renewable it
is therefore sustainable and so will never run
out.
Renewable energy facilities generally require
less maintenance than traditional generators.
Even more importantly, renewable energy
produces no waste products such as carbon
dioxide or other chemical pollutants, so has
minimum impact on the environment.
Renewable energy projects can also bring
economic benefits to many regional areas, as
most projects are located away from large
urban centers.
4. IMPACT OF RENEWABLE ENERGY
IN DS
Renewable generation (RG) that comes with
distribution system may exhibit a new set of
technical problems which often includes
problem of voltage rise instead of fall at
certain end points with RG integration into
the network and sometime the reversal of
power flow.
Other effect is that, wind turbine is designed
to shut down as a safety precaution in very
high winds, which means a wind turbine
supplying power into the grid might be liable
to stop without warning, leading to a sudden
drop in production which the network might
struggle to compensate for. If the proportion
of distributed energy is low, there will not be
any problem but when it is getting to 20%, a
level proposed by EU countries, then, a risk
of global outage is very high.
iency, reliability and power quality are very
important factors to be considered in the
integration of RG with Distributed system
others are cost of energy conversion,
appropriate load management, security and
safety.
Figure 2: Impact of RG on Feeder
Voltage Profile
6. CONCLUSION
The objective of this paper is to study the effect
of RES penetration on voltage stability at the
time of connecting and disconnecting wind,
solar or both with RES system. It shows the
impact of Renewable generation on DS with
voltage control strategies and presents the aspect
of smart grid technologies in voltage control as
the most appropriate voltage control at varying
wind speed and PV irradiance. The combination
of electrical energy storage and demand side
measures one operating from the supply side
(Energy Storage), the other from the demand
side (DSI), will potentially allow generation
plant, both traditional and renewable, to operate
in a more cost-effective manner. Coordination of
voltage control devices and RG for voltage
profile improvement can further be investigated.
REFERENCES
[1] J.O. Petinrin, and Mohamed Shaaban, 2016.
Impact of renewable generation on voltage control in
distribution systems. Renewable and Sustainable
Energy
Reviews,
770-783.
http://dx.doi.org/10.1016/j.rser.2016.06.073.
[2] M. Begović, A. Pregelj, A. Rohatgi and D.
Novosel, 2001. Impact of Renewable Distributed
Generation on Power Systems, Proceedings of the
34th Hawaii International Conference on System
Sciences, 1-10.
[3] Tareq Aziz, Sudarshan Dahal, and N.
Mithulananthan and Daniel Frances, 2010. Impact of
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23,
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widespread penetrations of renewable generation on
distribution system stability, Electrical and
Computer
Engineering
(ICECE),
doi: 10.1109/ICELCE.2010.5700697
[4] Dariush Shirmohammadi, 2010. Impacts of high
penetration of distributed and renewable resources
on transmission and distribution systems, IEEE,
Doi: 10.1109/ISGT.2010.5434736
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23,
2017 at GEC Banswara, www.apgres.in
Microbial pretreated Water hyacinth as an Energy Source
Diksha Srivastava Yashwant Raj Verma and Dr. Nafisa Ali
Department of Renewable Energy Engineering, College of Technology and Engineering, Maharana
Pratap University of Agriculture and Technology, Udaipur -313001, Rajasthan, India.
Abstract:
The present research work was undertaken to study the potential of water hyacinth in generation of
biogas; after a microbial pre-treatment. Water hyacinth, an aquatic weed is often associated with
uncontrolled growth and eutrophication. Culture of Phanerochaete chrysosporium, a lingocellulytic
fungus was used for microbial pre-treatment. Performance evaluation, in terms of biogas production was
checked in 2m3 Modified Deenbandhu biogas plant, which is fitted with a stirrer on its side to remove
scum formation in digester. The biogas production from the water hyacinth was only 1.92% more than
that of cattle dung but the methane content of the biogas from the water hyacinth was 10.71% higher
than that of cattle dung. The average NPK content of the digested slurry of the water hyacinth was
38.55%, 10.52% and 137.14% more than that of digested slurry of cattle dung respectively. This will
help to sort out the problems of cooking fuel, lightening, aquatic weed disposal, waste management and
sanitation etc.
Keywords: Water hyacinth, Modified Deenbandhu biogas plant, phanerochaete chrysosporium,
Biomethanation
1.
Introduction
Water hyacinth (Eichhornia Crassipes) has been
identified by the IUCN as one of the 100 most
aggressive invasive species (Tellez et al., 2008)
and recognized as one of the top 10 worst weeds
in the world (Patel 2012). It is characterized by
rapid growth rates, extensive dispersal
capabilities, large and rapid reproductive output
and broad environmental tolerance (Zhang et al.,
2010). Among all the control methods such as;
physical process, chemical process or biological
process, physical process is the best as it
provides both rid of water hyacinth which is a
major problem for hydrosphere and also
provides proper waste disposal of the taken out
weed from lakes.
Biogas technology in comparison to all other
renewable sources of energy is well developed
and easy to adopt for any person, as its
technological infrastructure is easily available at
large scale in Indian market for generating biogas.
Biogas is a product of biomethanation
process when fermentable organic material such
as cattle dung, kitchen waste, poultry droppings,
night soil wastes, agricultural wastes etc. are
subjected to anaerobic digestion in the presence
of methanogenic bacteria. This process is better
as the digested slurry from biogas plants is
available for its utilization as organic manure in
agriculture and horticulture as a substitute of
chemical fertilizers, and in pisciculture as a
nutritional feed for fish.
2.
Materials and Methods
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23,
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Figure 1: Collection and preparation of water
hyacinth for pre-treatment
The study was conducted at the Department of
Renewable Energy Engineering, College of
Technology
and
Engineering,
Udaipur
(Rajasthan). Water Hyacinth was collected from
the pond of the nearby village named Kanpur,
Udaipur (Rajasthan), and was chopped using
crusher machine under green house shed, as
shown in Figure1.
For the microbial treatment of Water Hyacinth,
a wood-rot fungus that is capable of degrading
lignin via its lignolytic enzymes; Phanerochaete
chrysosporium (NCIM 1197) was used. This
organism is termed as “white rot fungus”
because of its ability to degrade lignin. The
cellulosic portion of wood is attacked to a lesser
extent, resulting in the characteristic white color
of the degraded wood. Degradation of material
involves important extracellular enzymes such
as lignin peroxidase, manganese dependent
peroxidase, glyoxal oxidase and pyranose
oxidase (located in the interplasmic space of the
fungal cell wall) (Urek and Pazarlioglu, 2007).
The vials received from NCIM were kept as
parental cultures from which sub-cultures were
prepared in malt extract agar medium using
slants of test tubes and secondary sub-culture in
petri plates as shown in Figure 2.
Figure 2: Sub-cultures of Fungus
Further these subcultures were used for
preparing mother spawns. For this, one kg of
wheat grains was soaked in 1 liter water for
overnight. Next day the grains were boiled for
15-20 minutes, after boiling the grains, it was
soaked in the same water for 10-15 minutes and
then excess water was drained off using a wire
mesh sieve. The grains were surface dried on
white paper sheet and 12 gm gypsum (CaSO4
2H2O) and 3 gm calcium carbonate (CaCO3)
were mixed with these boiled grains, where the
gypsum was added to prevent the grains from
sticking to each other and calcium carbonate was
used to bring the pH to 6.5. The grains were then
filled in 500 ml conical flask up to three fourth
of the capacity, plugged with non-absorbent
cotton and sterilized in autoclave at 120°C + 2°C
and 15 lb psi for 1 to 1½ hours. Flasks were
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23,
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cooled at room temperature and then were
inoculated with colonized mycelium of
Phanerochaete chrysosporium by putting the
two bits of agar (from petri plates) just opposite
to each other in the inner side in the middle of
flasks and then incubated at 25 ± 1°C for 2
weeks. The flasks were shaken every day to
obtain homogenous growth of fungi. After 2
weeks of inoculation the flasks were ready as
spawn culture (Pant et al., 2006). A comparative
view of grain filled flasks, before and after sub
culturing is shown in Figure 3.
In field level the methodology adopted for
treatment of water hyacinth is as under-100 kg
of crushed Water Hyacinth was soaked
(overnight) in 70-80 lt. of water containing 0.05
percent
bavastine
and
0.25
percent
formaldehyde. This is done to sterilize the
organic waste (Deshmukh and Deshmukh,
2013). For fungal treatment, mother spawn of
Phanerochaete
chrysosporium
(prepared
previously) was spread on substrate layer by
layer in 3 canisters. These canisters were marked
and kept at ambient temperature for growth of
fungus for 3 days, as shown in Figure 4 (Ali,
2014). Further respectively first, second and
third canister was used for feeding biogas plant
so as to obtain sufficient growth of microbes for
three days and simultaneously filled with fresh
material and layer of microbes. This process was
repeated till the end of the experiment.
Figure 4: Preparation of mixture of pretreated water hyacinth and cattle dung
Figure 3: Before and after spawn growth
Figure 5: Deenbandhu Biogas Plant with
Mixing Unit
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23,
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3.
Results and Discussion
To check the feasibility of water hyacinth as a
substrate and adduct for biomethanation,
biochemical analysis of water hyacinth and
cattle dung was done. All the analysis was done
using standard methods as shown in Table No.1.
Table 1: Physico chemical analysis of water
hyacinth and cattle dung
Constitue pH TS VS N
P
K
nts
%
%
% % %
Water
6.0 9.6 82. 2.1 0.5 1.6
Hyacinth 8
1
65
6
8
3
Cattle
6.8 10. 81. 1.3 0.5 0.5
dung
2
72
54
8
2
5
The biochemical analysis of the feed material
before and after digestion, with respect to pH,
total solid content and volatile solid content were
done by standard methods and are shown in table
2.
Table 2: Characteristics of feed material
before and after digestion
Days of
Observation
10
15
20
25
pH
BD
AD
6.08
6.83
6.06
6.83
6.05
6.85
6.05
6.92
TS
BD
9.60
9.54
9.58
9.62
VS
AD
9.10
8.70
8.50
8.10
BD
82.90
82.50
82.60
81.85
AD
82.78
81.25
80.40
78.40
30
35
40
45
50
55
60
65
70
Average
6.07
6.09
6.08
6.09
6.10
6.09
6.10
6.10
6.09
6.08
6.92
6.95
6.96
6.92
6.91
6.87
6.90
6.89
6.87
6.89
9.61
9.59
9.62
9.64
9.64
9.63
9.64
9.62
9.60
9.61
8.00
7.80
7.50
7.46
7.10
7.30
7.40
7.12
7.18
7.78
82.68
82.73
83.18
82.56
82.60
82.87
82.50
82.89
82.63
82.65
77.10
75.80
74.52
74.00
73.72
73.56
72.83
72.75
72.80
76.14
WH: Water Hyacinth, BD: Before Digestion,
AD: After Digestion
pH value of the water hyacinth before digestion
was nearly constant during the whole process.
The average value of total solid content of water
hyacinth was found to be 7.78% and of cattle
dung was found to be 8.10%. Degradation in VS
content of water hyacinth was found to be
12.11%, while that in case of cattle dung was
found to be 11.10% which indicated the lower
biogas production from cattle as compare to
water hyacinth. The maximum and minimum
temperature of the environment near biogas
plant during digestion was found to be 45.70°C
and 12.50°C respectively.
Production of biogas depends on the degradation
of volatile solid matter and here degradation is
higher in water hyacinth as compare to cattle
dung which clearly indicates the reason of higher
biogas production from water hyacinth as
compare to cattle dung. Figure 6 shows the
biogas produced from water hyacinth and cattle
dung graphically, calculated using biogas flow
meter during the digestion process.
Biogas (m3)
Initially plant was fed with 100% cattle dung as
seeding material to enhance the rate of reaction
and then was replaced by pretreated water
hyacinth (Ali, 2010) with reduction ratio of 20%
(i.e. ratio between cattle dung and water hyacinth
was maintained as 50:0, 40:10, 30:20, 20:30,
10:40, 0:50 respectively after every one week). A
simple mechanical hand driven mixing unit was
developed and installed in the Modified
Deenbandhu biogas plant to solve the problems
of
choking
experienced
when
using
lignocellulosic material. It has an axle with four
vertical and two horizontal baffles on both side
of the centre. The whole unit was installed inside
the biogas plant perpendicular to the flow of feed
material in the plant having bearings on both
sides for ease in rotation. Handle for operating
the mixing unit was kept outside the plant. The
speed of rotation was 4 rpm as shown in figure
5.
2
1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
WH
CD
10 15 20 25 30 35 40 45 50 55 60 65 70
Days
Figure 6: Biogas production in m3 from the
water hyacinth and cattle dung
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Methane (%)
80
60
WH
40
CD
20
0
The biogas spent slurry was analyzed for
nutrients like nitrogen, phosphate and potash at
every 10 day’s interval. Results are presented in
figure 9,10and 11 respectively.
2.5
2
Nitrogen (%)
Figure 7 and 8 shows the amount of methane and
carbon dioxide content in biogas produced from
water hyacinth and cattle dung graphically during
digestion process.
The
maximum
and
minimum amount of methane content of the
biogas produced from the water hyacinth was
68.70% and 45.80% respectively. The average
methane content was found to be 63.33%. The
maximum and minimum amount of methane
content of the biogas produced from the cattle
dung was 59.80% and 45.90% respectively. The
average methane content was found to be
57.20%. Higher the amount of methane
percentage in biogas clearly denotes the quality of
biogas, which in turn increases the calorific value
of biogas. The maximum and minimum amount
of CO2 content of the biogas produced from the
water hyacinth was 51.80% and 28.80%
respectively. The average CO2 content was
found to be 34.19%. Amount of CO2 in biogas
reduce the calorific value of biogas. Lower
amount of CO2 in biogas produced from water
hyacinth indicates the higher calorific value as
compare to that of cattle dung.
30
WH
20
CD
0.5
0
10 15 20 25 30 35 40 45 50 55 60 65 70
Days
Figure 8: CO2 percentage in the biogas
30
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
40
Days
50
60
70
WH
CD
10
10
20
Figure 9: Nitrogen percentage in digested
material
Nitrogen content of the fresh water hyacinth was
found to be 2.16% and after digestion, an
increase of 10.18% was observed. Range of the
nitrogen content in the digested slurry of water
hyacinth was found to be 2.16% to 2.38% and
the average nitrogen content was found to be
2.30%. Nitrogen content of the fresh cattle dung
was found to be 1.38% and after digestion, an
increase of 36.95% was observed. Range of the
nitrogen content in the digested slurry of cattle
dung was found to be 1.38% to 1.89% and the
average nitrogen content was found to be 1.66%.
Due to higher value of nitrogen content in fresh
water hyacinth than that of cattle dung, it is
higher in digested slurry.
Phosphate (%)
CO2 (%)
40
WH
CD
10
Figure 7: Methane percentage in the biogas
50
1
0
10 15 20 25 30 35 40 45 50 55 60 65 70
Days
60
1.5
20
30
40
Days
50
60
70
Figure 10: Phosphate percentage in digested
material
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Potash (%)
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1.8
1.6
1.4
1.2
1
0.8
0.6
0.4
0.2
0
WH
CD
10
20
30
40 50
Days
60
70
Figure 11: Potash percentage in digested
material
Phosphate content of the fresh water hyacinth
was found to be 0.58% and after digestion, an
increase of 15.51% was observed. Range of the
phosphate content in the digested slurry of water
hyacinth was found to be 0.58% to 0.67%, the
average phosphate content was found to be
0.63%. Phosphate content of the fresh cattle
dung was found to be 0.52% and after digestion,
an increase of 19.23% was observed. Range of
the phosphate content in the digested slurry of
cattle dung was found to be 0.52% to 0.62% and
the average phosphate content was found to be
0.57%.
Potash content of the fresh water hyacinth was
found to be 1.63% and after digestion, an
increase of 4.29% was observed. Range of the
potash content in the digested slurry of water
hyacinth was found to be 1.63% to 1.70%, the
average potash content was found to be 1.66%.
Potash content of the fresh cattle dung
was found to be 0.55% and after digestion, an
increase of 47.27% was observed. Range of the
potash content in the digested slurry of cattle
dung was found to be 0.55% to 0.81%, the
average potash content was found to be 0.70%.
4.
Conclusion
In this study, an attempt has been made to
utilize an obnoxious aquatic weed, water
hyacinth. It is a serious hazard to various lakes,
ponds or any other stagnant water body. This
study has determined the potential of generation
of biogas after a microbial pre-treatment, which
will help to sort out the problems of aquatic
weed disposal, waste management, sanitation,
cooking fuel, fuel for lightening, organic manure
production etc. The biogas production from the
water hyacinth was 1.92% more than that of
cattle dung but the methane content of the biogas
from the water hyacinth was 10.71% higher than
that of cattle dung. After biogas production, biochemical analysis of the digested slurry was
done which concludes that the average NPK
content of the digested slurry of water hyacinth
was 38.55%, 10.52% and 137.14% more than
that of digested slurry of cattle dung
respectively.
References
1. Ali, N., Chaudhary, B.L. and Khandelwal,
S.K. 2004. Better use of water hyacinth for
fuel,
manure
and
pollution
free
environment.
Indian
Journal
of
Environmental Protection 24 : 297-303.
2. Ali, N., Chaudhary, B.L. and Panwar, N.L.
2014. The fungal pre-treatment of maize
cob heart and water hyacinth for enhanced
biomethanation. International Journal of
Green Energy 11 : 40-49.
3. Bak, J.S., Ko, J.K., Choi, I.G., Park, Y.C.,
Seo, J.H. and Kim, K.H. 2009. Fungal
pretreatment
of
lignocellulose
by
Phanerochaete chrysosporium to produce
ethanol from rice straw. Biotechnology and
Bioengineering 104 : 471-82.
4. Biogas Technology Development Division.
Ministry of New and Renewable Energy.
(http://mnre.gov.in/schemes/decentralizedsystems/schemes-2/).
5. Deshmukh, S. and V.R. Deshmukh, V.R.
2013. Bio-efficiency of mushroom on
different agro-waste. PKV Research Journal
37 : 50-52.
6. Fadairo, A.A. and Fagbenle, R.O. 2014.
Biogas production from water hyacinth
blends. In : 10th International Conference
on Heat Transfer, Fluid Mechanics and
Thermodynamics held at Orlando, Florida,
U.S.A. during July 14-16, 2014, pp. 792799.
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7.
8.
9.
10.
11.
12.
13.
14.
15.
Frezina, N.C.A. 2013. Water hyacinth as a
substrate for plant-microbial fuel cell to
clean water and produce electricity in
marshes. International Journal of Scientific
& Engineering Research 4 : 1297-1312.
Harley, L.S., Julien, M.H., and Wright, A.D.
1997. Water Hyacinth: A tropical
worldwide problem and methods for its
Control. In : Proceedings of the First
Meeting of the International Water
Hyacinth Consortium held at World Bank,
Washington during March 18-19, 1997.
Jayaweera, M.W., Dilhani, J.A., Kularatne,
R.K. and Wijeyekoon, S.L. 2007. Biogas
production
from
water
hyacinth
(Eichhornia crassipes) grown under
different nitrogen concentrations. Journal of
Environmental Science and Health. Part A,
Toxic/Hazardous
Substances
and
Environmental Engineering 42 : 925-932.
Lancer, L. and Krake, K. 2002. Aquatic
weeds and their management. International
Commission on Irrigation and Drainage 1 :
22-57.
Njogu, P., Kinyua, R., Muthoni P. and
Nemoto Y. 2016. Biogas production using
water hyacinth (Eicchornia crassipes) for
electricity generation in Kenya. Energy and
Power Engineering 7 : 209-216.
Patel, S. 2012. Threats, management and
envisaged utilizations of aquatic weed
Eichhornia crassipes: An overview.
Reviews in Environmental Science and
Biotechnology 11 : 249–259.
Sawatdeenarunat, C., Surendra, K.C.,
Takara, D., Oechsner, H. and Khanal, S.K.
2015.
Anaerobic
digestion
of
lignocellulosic biomass: Challenges and
opportunities. Bioresource Technology 178
: 178-186.
Singh, D. and Chen, S. 2008. The white-rot
fungus Phanerochaete chrysosporium:
conditions for the production of lignindegrading enzymes. Applied Microbiology
and Biotechnology 81 : 399-417.
Tellez, T., Lopez, E., Granado, G., Perez,
E., Lopez, R., and Guzman, J. 2008. The
water hyacinth, Eichhornia crassipes: An
invasive plant in the Guadiana River Basin
(Spain). Aquatic Invasions 3 : 42-53.
16. Xing, J., Criddle, C. and Hickey, R. 1997.
Effects of a long-term periodic substrate
perturbation on an anaerobic community.
Water Research 31 : 2195-2204.
17. Zhang, Y., Zhang, D., Barrett, S., 2010.
Genetic uniformity characterizes the
invasive spread of water hyacinth
(Eichhornia crassipes), a clonal aquatic
plant. Molecular Ecology 19 : 1774-1786.
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Effect of Viscosity in Biomechanics for the Fluid: A Review
Vinod Kumar Bais1 and Ankur Kulshreshtha2
1
Manav Bharti Universty, Solan, HP, India.
2
GEC, Banswara, Rajasthan, India.
Corresponding Author: Ankur_kulshreshtha@yahoo.in
Abstract:
The viscosity of a liquid is the correlation of shear stress and velocity gradient. It is the quantity of force
need to obtain that substance moving in circular tube. Mathematical techniques are used to find various
types of viscosity for fluid and obtain the result with the numerical example to discuss the feature for
multiple applications in biomechanics.
Key Terms: Shear stress, Mathematical Model, Fluid Dynamics, Viscosity.
1.
Introduction:
Biomechanics focuses on the application of
mechanics in the field of living organism for
human development. The biomechanics of
human beings is a main part of kinesiology. In
this regard, construction of mathematical model
to solve the problems of the biomechanics of the
human skeleton and its various body parts and
other biomaterials like artificial blood vessel and
so on. The viscosity of a fluid is a measure of its
resistance to gradual deformation by shear
stress. It is the force per unit area, therefore the
viscosity is equal to force divided by the area. In
medical field, the viscosity is a direct
measurement of the blood to flow through the
blood vessels. Also, the study the stress, we
focus on the length and diameter of the vessels.
Bessonov N. et. al. 2016 discussed methods of
blood flow modeling that blood assumed as a
heterogeneous fluid and analysis rheology and
non-Newtonian properties. The constructive
model for incompressible viscous fluids based
on the assumption that the extra stress tensor is
proportional to the symmetric part of the
velocity gradient, 𝜏 = 2𝜇𝐷. Where μ is the
viscosity and 𝐷 = ∇𝑢 + ∇𝑢 /2 is the rate of the
deformation tensor. Also, analyze an
equilibrium stage of blood vessel and internal
blood pressure by the Newton method.
Alexander R. McN. Has worked on modeling
approaches in biomechanics in 2003. In this
work, conceptual models, physical models and
mathematical models has been provided for the
study of folding mechanism of insect wings and
study the pattern and behavior of the wings and
leg muscles. Boda M.A. et. al. 2015 has provided
the analysis of kinematic viscosity for high and
low sticky liquids at different level of
temperature. Nithiarasu P. published his book
“Biofluid Dynamics”, in which there are
sufficient theoretically information about the
biofluids and many other solving techniques to
find Stress and strain and other terms. Kim B. H.
et. al 2013 has worked on effect of the fluid
viscosity on the liquid- feeding flow phenomena
of a female mosquito. The study is focused on
the feeding mechanism and viscosity of the
fluids in food canal. Sanjeev Kumar et. al. 2009
discussed the effect of porous parameter for the
blood flow in a time dependent stenotic artery
and to find the stress and pressure on wall, used
the Navier-Stokes and the continuity equations.
2.
Mathematical Models:
Model 1: Kinematic Viscosity
It is the measure of the inherent resistance of a
fluid to flow when no external force is exerted,
except gravity. Mathematically, it can be
calculated by dividing the absolute viscosity of a
liquid with the liquid mass density. It is denoted
by ν and defined as
𝜂
𝜈=
𝜌
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Where 𝜈 = 𝐾𝑖𝑛𝑒𝑚𝑎𝑡𝑖𝑐 𝑉𝑖𝑠𝑐𝑜𝑠𝑖𝑡𝑦
𝜂=
𝐷𝑦𝑛𝑎𝑚𝑖𝑐𝑠 𝑉𝑖𝑠𝑐𝑜𝑠𝑖𝑡𝑦 and 𝜌 = 𝐹𝑙𝑢𝑖𝑑 𝐷𝑒𝑛𝑠𝑖𝑡𝑦.
For example: Obtain the kinematic viscosity,
for a liter of mercury with weight 1.95 Kg.
Solution: Here, first find the density mass of
mercury.
.
Density of mercury (𝜌) =
=
=
.
= 1950
Since the dynamic viscosity of the mercury (𝜂)
= 1.526 Pa*s.
Now the kinematic viscosity is calculated by the
formula:
𝜈=
.
𝜂 1.526 Pa ∗ s 1.526 N ∗ s/𝑚
=
=
𝐾𝑔
𝐾𝑔
𝜌
1950
1950
𝑚
𝑚
= 0.00078256 𝑚 /𝑠
Model 2: Dynamic Viscosity with Tangential
Force
It is the tangential force required to move one
horizontal plane of a fluid with respect to another
plane. It is denoted by 𝜂 and defined as
𝜏
𝜂=
𝛾
Where
𝜂 = 𝐷𝑦𝑛𝑎𝑚𝑖𝑐𝑠 𝑉𝑖𝑠𝑐𝑜𝑠𝑖𝑡𝑦 ,
𝜏=
𝑆ℎ𝑒𝑎𝑟𝑖𝑛𝑔 𝑆𝑡𝑟𝑒𝑠𝑠 and 𝛾 = 𝑆ℎ𝑒𝑎𝑟 𝑅𝑎𝑡𝑒.
For example: Calculate the pressure necessary
to move a system of liquid with a shear rate of
0.33 per second and the value of dynamics
viscosity is 0.019 Pa*s.
Solution: To find the pressure (stress), use
dynamics viscosity formula
𝜂 = => 𝜏 = 𝜂 ∗ 𝛾……….(1)
𝜈=
Where
𝛾 = 0.33 𝑝𝑒𝑟 𝑠𝑒𝑐𝑜𝑛𝑑 𝑎𝑛𝑑 𝜂 =
0.019 𝑃𝑎 ∗ 𝑠. Then from equation (1) we get
𝜏 = 𝜂 ∗ 𝛾 = (0.019 𝑃𝑎 ∗ 𝑠)
∗ (0.33 𝑝𝑒𝑟 𝑠𝑒𝑐𝑜𝑛𝑑)
𝜏 = 0.00627 𝑃𝑎 =
0.00627 𝑁/𝑚
Model 3: Viscosity, Shear Stress and Shear
Rate
Fluid mechanics of polymers are modeled
as steady flow in shear flow.
Shear flow can be measured with pressures
in the fluid and a resulting shear stress.
Shear flow is defined as flow caused by
tangential movement. This imparts a shear
stress on the fluid.
Shear rate is a ratio of velocity and distance
and has units per second. It is defined as
𝛾̇ =
.𝑚 =
= (𝑠 )
Where h is the distance between two layer
of tube and 𝑣 is the velocity of upper layer.
Shear stress is proportional to shear rate
with a viscosity constant or viscosity
function.
Shear Stress is defined as 𝜏 = (𝑁/𝑚 )
Where F is force applied on the area (A) of
the tube.
3.
Result and Conclusion:
Biomechanics is used to explanations of the
mechanical behavior of living organisms. Also,
there is an important to understand the basic
relationship between stress and strain. It has
many mathematical techniques to construct the
model for the study of mechanical behavior like
pressure and stress of vessel of human body as
shown in the figure.
Source: Book Bio fluid Dynamics
Biomechanics has advantage of engineering
principles and requires understanding of
mathematical modeling, mechanics and biology.
We have discussed some model with numerical
examples to find various factors as shear stress,
shear rate, and viscosity. It has play an important
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role in the field of medical sciences specially in
orthopedics and obtains a good joint implication,
it is also optimizing the different shape of
implants so they may better resist extreme a long
time mechanical demands in medical field. In
this field shear stress, shear rate, viscosity is the
important tools for designing the new shapes of
various fluid tube and various parts of skeleton
and so on and provide a new way to researchers,
mechanical manufactures and software designer
to develop existing and new shapes.
References:
1 N. Bessonov (et. al.) “Methods of blood flow
modeling”, Math. Model. Nat. Phenom. Vol. 11,
No. 1, 2016, pp. 1-25
2 R. McN. Alexander, “Modelling approaches in
biomechanics”, The Royal Society, UK, 6
August, 2003.
3 P. Nithiarasu, published his book Bio fluid
Dynamics, UK.
4 M A Boda (et. al.) “Analysis of Kinematic
Viscosity for Liquids by Varying Temperature”,
IJIRSET, Vol. 4, Issue 4, April 2015
5 Bo Heum Kim (et. al.) “Effect of fluid
viscosity on the liquid-feeding flow phenomena
of a
female
mosquito”,
The
Journal
of
Experimental Biology 216, 952-959, 2013.
6 Sanjeev Kumar, Archana Dixit, “Effect of
Porous Parameter for the Blood Flow in a time
Dependent Stenotic Artery”, Indian Journal of
Biomechanics: Special Issue (NCBM 7-8 March
2009).
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Thermodynamic investigation on biomass derived syngas fueled
combined cycle power plant
Mohd Parvez, Abdul Khaliq
Department of Mechanical Engineering, Al-Falah University, Faridabad (Haryana) India
Mechanical Engg. Dept., King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia
Corresponding Author: mparvezalig@rediffmail.com
Abstract
This article reports the results of syngas fueled combined power cycle which was analyzed from both
energy and exergy point of views. A parametric investigation was carried out to ascertain the effects of
change in biomass material, gas turbine inlet temperature, and steam turbine inlet pressure on
performance of the biomass gasifier integrated combined cycle plant. The results obtained clearly reveal
that first law efficiency and second law efficiency of the combined cycle significantly vary with the
change in gas turbine inlet temperature and steam turbine inlet pressure but the change in biomass
material shows small variation in these parameters.
Keywords: combined cycle, thermo-chemical equilibrium, gasification, syngas, power generation
Corresponding author:
1. Introduction
The energy and environment norms regarding
the ozone layer depletion and the global
warming are becoming more and more stringent
in almost all over the world. In this challenging
scenario, biomass gasification energy for
producing electricity gaining popularity,
because they use zero global warming and ozone
depletion. However, these systems have lower
efficiency than the conventional power plants
and need optimization from thermodynamic
point of view. Direct combustion of biomass is
worsened by heterogeneous composition of
waste biomass leading to unacceptable
consequences because it has low efficiency and
a high environmental impact, due to the
unburned hydrocarbons and the release of
particulates matter. Gasification of biomass is an
attractive technology for power generation. The
use of biomass gasification process is a key
element in an advanced gas turbine combined
cycle system.
Various investigations based on conventional
first – law of thermodynamic method have been
carried out in the past on biomass integrated
gasification
combined
cycle.
These
investigations laid a foundation for the proper
utilization of biomass using gasification
technology effectively. Marcio [1] proposed a
thermodynamic methodology for the viability of
a power generating system based on atmospheric
gasification of sugarcane bagasse using
fluidized- bed gasifier. In this study various
configurations of the power unit were tried until
the most efficient was found. Ciferno and
Marano [2] reported benchmarking biomass
gasification technology for fuels, chemicals and
hydrogen production. Larson et al. [3] carried
out the cost benefit assessment of biomass
gasification power generation in the pulp and
paper industry. De Souza Santos [4] described a
theory of solid fuels combustion and
gasification. The material reported has been
found of much use for the analysis of solid
fueled power generation system simultaneously
involved in the processes of gasification and
combustion.
Most of the studies reported in the literature as
discussed above are based on first law analysis
or energy balance approach. First – law of
thermodynamics simply deals with the
conversion of energy from one form to another.
It fails to identify and quantify the sources of
thermodynamic losses which are responsible to
deteriorate the performance of thermal energy
systems and cannot answer why the actual
operational performance of energy system differ
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from the design one. In order to overcome with
these limitations of the first law, second law of
thermodynamics has been adopted by many
investigators for the last decade and it is
observed that combined application of first and
second laws of thermodynamics results to
provide credible information about the real
performance of thermal power generation
systems [5]. Wu et al. [6] carried out first law
simulation for 450 kW gas engine using
fluidized bed gasifier and reported that its
overall efficiency can be achieved 26-28%. For
rice husk and agricultural waste plant they found
gasifier as the major source of exergy losses.
Brown et al. [7] addresses the issues of thermo
economic assessment of wood gasification for
electricity generation. They identified the
operating conditions for maximum exergy
efficiency of the plant with minimal investment
cost. Bhattacharya et al. [8] conducted a
thermodynamic analysis of biomass integrated
gasification combined cycle considering the
combustion of supplementary biomass fuel
using the oxygen available in gas turbine
exhaust. There results show the plant
efficiencies increase with the increase in both
pressure and temperature ratios: however, the
latter has a stronger influence than the former.
Srinivas et al. [9] predicted the thermal
performance of a biomass based IGCC plant and
examined the effects of gasifier conditions on
the efficiency and power generation capacity of
the plant as well as their effect on NOX and CO2
emissions.
Most
recently
theoretical
investigations on different biomass material
gasification at ambient conditions for gas turbine
power generation have also been presented for
various operating conditions [10-12].
In this context the current study has been carried
out to evaluate the thermodynamic performance
of various biomass fueled combined gas - steam
cycle for power generation. The effect of change
in biomass material and some influenced
thermodynamic parameters have been observed
on the first law and second law performance of
the proposed cycle.
2. Problem formulation
Figure 1 shows a thermo – chemical model of
biomass gasification combined power cycle
power plant. The biomass fed to the gasifier. The
compressed air at state 2 and saturated steam at
state 4 enter the gasifer where syngas is
produced and goes to the combustion chamber
after passing through a gas cleanup unit where
tar and char removed. In combustion chamber
the chemical reaction are taking place. The
products of combustion go to the gas turbine
where they expand and produce power. The
exhaust gasses of gas turbine enter the heat
recovery steam generator (HRSG) where
superheated steam is produced. This superheated
steam is used to run the steam turbine and
produce electric power and exhaust steam from
steam turbine routed to the condenser where its
phase changes from vapor to liquid and then
pumped back to the HRSG. The waste gases
available at the exit of HRSG discharge to the
atmosphere at ambient pressure. The analysis
was carried out as per the assumptions taken by
Wu et al. (2008) [6]
3. First and second law analyses of a
combined power cycle
The gasification reactions in the gasifier are
explain as
C H O N +wH O + a (O + 3.76N )
+a H O
= b CH + b CO + b CO + b H + b H O +
b N
(1)
The syngas obtained after gasification was used
in combustion chamber as a fuel reported as
𝑏 𝐶𝐻 + 𝑏 𝐶𝑂 + 𝑏 𝐶𝑂 + 𝑏 𝐻 + 𝑏 𝐻 𝑂
+ 𝑏 𝑁 + 𝑎 (𝑂 + 3.76𝑁 )
= 𝑏 𝐶𝑂 + 𝑏 𝐻 𝑂 + 𝑏 𝑁
(2)
The composition of syngas formed after
gasification of biomass was computed after
following the model developed by Bhattacharya
et al. [8].
The thermodynamic performance parameters for
the first and second law efficiency of the
proposed combined cycle were calculated after
using
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𝜂 =
̇
̇
̇
̇
(3)
̇
𝜂 =
̇
̇
̇
̇
̇
,
(4)
4. Results and discussion
The present study is carried out to identify the
effect of various influenced parameters on the
performance of the integrated gasification
combustion chamber in the range of operation,
gas turbine inlet temperature (1273 –1473K),
turbine inlet pressure (30 bar to 70 bar) and
approach temperature (288 K). The proposed
model developed in this paper for solid waste,
rice husk and sugarcane bagasse are tested by
comparing the result with the published papers
of relevant researchers [12].
Figs. 2-3 shows the variation of first and second
law efficiencies of biomass gasification of
combined power cycle with the change in gas
turbine inlet temperature. In general, second law
efficiencies of combined are slightly lower than
their first law efficiencies. This is due to the fact
that the chemical exergy of biomass fuel which
is considered as the input in second law analysis
is higher than the calorific value of the fuel
which is considered as the input in the first law
analysis. Figs. 2-3 reveal that both first law and
second law efficiencies increase linearly as gas
turbine inlet temperature for all three cases of
biomass considered. It is further noticed that
both first and second law efficiencies of
combined power cycle are higher for solid waste
and lower for sugarcane bagasse. This is due to
the fact that gasifier temperature and lower
heating value of syngas is higher in case of solid
waste and lower in case of sugarcane bagasse.
Figs. 4-5 shows the variation of first and second
law efficiencies of combined power cycle with
the change in steam turbine inlet pressure. It is
found that both first and second law efficiencies
decrease with the increase in steam turbine inlet
pressure. The reason for this kind of trend is that
increase in steam turbine inlet pressure results in
lower mass flow rate of steam produced in the
HRSG which in turn reduces the steam output
and hence decreases the overall efficiency of the
cycle. Since the contribution of gas turbine
towards the overall power generation is much
higher and is three times larger than the
contribution of the steam turbine, and change in
steam turbine pressure only effects the steam
turbine output not the gas turbine output,
therefore, first law efficiency of combined
power cycle slightly drops with the increase in
steam turbine inlet pressure. For the similar
reasons, second law efficiency also drops
slightly with the same.
5. Conclusions
The proposed biomass derived syngas fueled
combined power cycle was analyzed by using
first and second law of thermodynamics. The
performance of the system was examined under
the variation of gas turbine and steam turbine.
The main conclusions drawn from this study can
be summarized as follows:
Both first and second law efficiencies
increases considerably with the rise of gas
turbine inlet temperature. First law efficiency
has been found maximum for solid waste
and minimum for sugarcane bagasse.
Second law efficiency also increases
significantly with the increase in gas turbine
inlet temperature and it was maximum for
solid waste and minimum for sugarcane
bagasse fueled cycle.
Both first and second law efficiencies
decrease significantly with the increase in
steam turbine inlet pressure.
Nomenclature
𝑊̇
ηI
ηII
φ
1-8
a-e
power (KW)
first law efficiency
second law efficiency
exergy ratio
state points of Brayton cycle
state points of the steam cycle
References
[1] Marcio L.de Souza – Santos. A feasibility
study of an alternative power generation system
based on biomass gasification / gas turbine
concept”. Fuel 1999; 78: 529-538.
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[2] Ciferno J.P, Marano J.J. Benchmarking
biomass gasification technologies for fuels,
chemicals and hydrogen production. U.S
Department of Energy National Energy
Technology Laboratory 2002.
[3] Larson E.D, Consonni S, Katofsky R.E. A
cost-benefit assessment of biomass gasification
power generation in the pulp and paper industry.
Energy
Group
Publications,
Princeton
University, Princeton, NJ 2003.
[4] Marcio L. de Souza-Santos. Solid fuels
combustion and gasification: modeling,
simulation and equipment operations”. CRS
Press, Taylor & Francis Group 2010.
[5] Dincer I, Rosen M.A. Exergy. 2nd edition,
Elsevier; New York 2012.
[6] Wu C, Yin X, Ma L, Zhou Z and Chen H.
Design and operation of a 5.5 MWe biomass
integrated
gasification
combined
cycle
demonstration plant”. Energy & Fuels 2008; 22:
4259-4264.
[7] Brown D, Gassner M, Fuchino T, Marechal
F. Thermo-economic analysis for the optimal
conceptual design of biomass gasification
energy conversion systems. Applied Thermal
Engineering 2009; 29: 2137-2152.
[8] Bhattacharya A, Manna D, Paul B, Datta A.
Biomass integrated gasification combined cycle
power generation with supplementary biomass
firing: Energy and exergy based performance
analysis. Energy 2011; 36 (5), pp 2599-2610.
[9] Srinivas T, Reddy B.V and Gupta
A.V.S.S.K.S. Thermal performance prediction
of a biomass based integrated gasification
combined cycle plant. Journal of Energy
Resources Technology 2012; Vol. 134/ 0210021-021002-9.
[10] Saeidi S, Mahmoudi SMS, Nami H, Yari M.
Energy and exergy analyses of a novel near zero
emission plant: Combination of MATIANT
cycle with gasification unit. Applied Thermal
Engineering 2016; 108: 893-904.
[11] Athari H, Soltani S, Rosen M, Mahmoudi
SMS,
Morosuk
T.
A
comparative
exergoeconomic evaluation of biomass post-
firing and co-firing combined power plants.
Biofuels 2017; 8 (1): 1-15.
[12] Parvez M. Investigation on thermodynamic
behavior of apple juice waste and sugarcane
bagasse gasified fuelled combined cycle power
generation
system”.
Biofuels
2017;
http://dx.doi.org/10.1080/17597269.2017.1374
768.
4
5
Gas
Cleaner
Unit
Com
Comb
busti
ustion
Gasif
Gasifi
ier
er
2
3
e
St
Ste
ea
am
Tu
7
H
H
R
R
S
S
G
G
G
Ga
sas
Bioma
ss
b
3
a
6
Comp
1 ressor
2
Cond
c
enser
d
Feed
8
A
i
To Stack Gases to
Atmosphere
Figure 1 Schematic diagram of biomass
fueled combined power cycle plant
41
First law efficiency of Solid waste
40
First law efficiency for Rice husk
39
38
37
36
35
34
33
32
1250
1300
1350
1400
1450
1500
Figure 2 Variation of first law efficiency with
turbine inlet temperature of combined power
cycle
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40
Second law efficiency of Solid
waste
Second law efficiency of Rice
husk
38
36
34
32
30
28
1250
1300
1350
1400
1450
1500
Figure 3 Variation of second law efficiency
with turbine inlet temperature of combined
power cycle
39
First law efficiency of Solid waste
38
37
36
35
34
33
32
30
40
50
60
70
80
Figure 4 Variation of first law efficiency with
pressure ratio of combined cycle power cycle
Second law efficiency of Solid
waste
Second law efficiency of Rice husk
39
38
37
36
35
34
33
32
31
30
30
40
50
60
70
80
Figure 5 Variation of second law efficiency
with pressure ratio of combined cycle power
cycle
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Bio Fuel: Need for the sustainable Generation
Sunil Sharma, Vishnu Inani
Department of Electronics & Communication Engg, Pacific University, Udaipur
Corresponding Author: ersharma.sunil@gmail.co, vishnuinani77@gmail.com
INTRODUCTION
Bioenergy is energy derived from biofuels. Biofuels are fuels produced directly or indirectly from
organic material – biomass – including plant materials and animal waste.
Overall, bioenergy covers approximately 10% of the total world energy demand. Traditional
unprocessed biomass such as fuelwood, charcoal and animal dung accounts for most of this and
represents the main source of energy for a large number of people in developing countries who use it
mainly for cooking and heating.
More advanced and efficient conversion technologies now allow the
extraction
of
biofuels from materials such as wood, crops and waste material. Biofuels can be solid, gaseous or
liquid, even though the term is often used in the literature in a narrow sense to refer only to liquid
biofuels for transport.
Biofuels may be derived from agricultural crops, including conventional food plants or from special
energy crops. Biofuels may also be derived from forestry, agricultural or fishery products or municipal
wastes, as well as from agro-industry, food industry and food service by-products and wastes.
A distinction is made between primary and secondary biofuels. In the case of primary biofuels, such
as fuelwood, wood chips and pellets, organic materials are used in an unprocessed form, primarily for
heating,
cooking or electricity production. Secondary biofuels result from processing of biomass and include
liquid biofuels such as ethanol and biodiesel that can be used in vehicles and industrial processes.
Bioenergy is mainly used in homes (80%), to a lesser extent in industry (18%), while liquid biofuels
for transport still play a limited role (2%)
TYPES OF LIQUID BIOFUELS
The most widely used liquid biofuels are ethanol
and biodiesel.
Ethanol is a type of alcohol that can be produced
using any feedstock containing significant
amounts of sugar, such as sugar cane or sugar
beet, or starch, such as maize and wheat. Sugar
can be directly fermented to alcohol, while
starch first needs to be converted to sugar. The
fermentation process is similar to that used to
make wine or beer, and pure ethanol is obtained
by distillation. The main producers are Brazil
and the USA. Ethanol can be blended with petrol
or burned in nearly pure form in slightly
modified spark-ignition engines. A liter of
ethanol contains approximately two thirds of the
energy provided by a liter of petrol. However,
when mixed with petrol, it improves the
combustion performance and lowers the
emissions of carbon monoxide and sulphur oxide.
Biodiesel is produced, mainly in the European
Union, by combining vegetable oil or animal fat
with an alcohol. Biodiesel can be blended with
traditional diesel fuel or burned in its pure form in
compression ignition engines. Its energy content
is somewhat less than that of diesel (88 to 95%).
Biodiesel can be derived from a wide range of
oils, including rapeseed, soybean, palm, coconut
or jatropha oils and therefore the resulting fuels
can display a greater variety of physical properties
than ethanol.
SECOND-GENERATION BIOFUELS
Currently used liquid biofuels, which include
ethanol produced
from crops which is
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containing sugar
and starch and biodiesel from oilseeds, are
referred
to
as
first-generation
biofuels. These fuels only use a portion of the
energy potentially available in the biomass.
Most plant matter is composed of cellulose,
hemicellulose and lignin, and “secondgeneration biofuel” technologies refer to
processes able to convert these components to
liquid fuels. Once commercially viable, these
could significantly expand the volume and
variety of sources that could be used for biofuel
production.
Potential cellulosic sources include municipal
waste and waste products from agriculture,
forestry, processing industry as well as new
energy crops such as fast-growing trees and
grasses. As a result second generation biofuel
production could present major advantages in
terms of environmental sustainability and
reduced competition for land with food and feed
production. It could also offer advantages in
terms of greenhouse gas emissions. Various
techniques
are currently being developed to
produce second generation biofuels. However, it
is uncertain when such technologies will enter
production on a significant commercial scale.
The conversion
from
cellulose to ethanol involves
two steps.
The cellulosic and
cellulosic
hemi
components of the plant material are first broken
down into sugars, which are then fermented to
obtain ethanol. The first step is technically
difficult, although research continues on
developing efficient and cost-effective ways of
carrying out the process. Lignin cannot be
converted to ethanol, but it can provide the
necessary energy for the conversion process.
Current world oil demand amounts to about
4000 Million tonnes of oil equivalent (Mtoe)
While the productionof
liquid
biofuels
amounts
to 36
More representing less
than 1% of this world demand.
Around 85% of the liquid biofuels are currently
produced in the form of bioethanol with the main
producers being Brazil and the USA. Biodiesel
production is essentially concentrated in the
European Union.
Large-scale production of biofuels from crops
requires large land areas to grow them, which
generates increasing competition for natural
resources, notably land and water. Crop yields per
hectare vary widely depending on the type of
crop, the country
and the production system. Currently, ethanol
production from sugar cane and sugar beet
produces the highest yields per hectare.
DRIVERS OF BIOFUEL POLICIES
The main drivers behind government
support for biofuels in OECD countries are
concerns about climate change and energy
security, and the political will to support the farm
sector through increased demand for agricultural
products.
Energy Security Secure access to energy is a
longstanding concern in many countries. The
recent increases in oil and other energy prices
have increased the incentive to promote
alternative sources of energy. Strong demand
from rapidly developing countries, especially
China and India, is adding to concerns over future
energy prices and supplies. The transport sector
depends mainly on oil. Liquid biofuels represent
the main alternative source that can supply fuels
suitable for use in current vehicles, without
radical changes to transport technologies.
Climate change There is increasing concern about
human-induced climate change, and the effects of
greenhouse gas emissions on rising global
temperatures. Bioenergy is often seen as a way to
reduce greenhouse gas emissions.
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policy measures are influencing biofuel
development?
Policies on agriculture, energy, transport,
environment and trade all have an influence on
biofuel production. Schemes to promote and
support biofuels have been introduced both in
OECD and developing countries. Without these
incentives, widespread biofuel production would
in most cases not have been commercially
viable.
prices of biofuels and provide an incentive for
domestic
The policies used by governments to promote
and support biofuel development include various
instruments. They can support the biofuel supply
chain at different stages.
sources.
o Agricultural policies existed well before the
introduction of biofuels. They include
agricultural subsidies and price support
mechanisms
which
directly
production.
Tax incentives or penalties are among the
most widely used instruments for stimulating
demand for biofuels and can drastically affect the
competitiveness of biofuels compared to other
energy
o
o Research and development is generally
aimed at improving the efficiency and costeffectiveness of biofuel production, and
identifying sustainable feedstocks. In developed
countries an increasing proportion of public
research and development funding is directed
towards
affect
production levels and prices of biofuel crops as
well as production systems and methods. These
policies also have implications at international
level for agricultural trade and geographical
pattern of agricultural production.
Blending mandates defining the overall
amount or proportion of biofuel that must be
blended with petrol and diesel are
o
increasingly being imposed.
Subsidies and support for the distribution
and use of biofuels are key policy components in
most countries that promote the use of biofuels.
Several countries are subsidizing or mandating
investments in infrastructure for biofuel storage,
transportation and use, especially towards
bioethanol which requires major investments in
equipment.
o
Tariffs or import barriers are duties
usually imposed on imported goods. They are
widely used on biofuels to protect the national
agriculture and biofuel sectors, support domestic
o
second-generation biofuel technologies, in
particular cellulosic ethanol andbiomass-derived
alternatives to petroleum-based diesel.
Impacts of biofuel policies on international
markets and trade?
o assesses the net effect on greenhouse gas
emissions of replacing fossil fuels by biofuels, we
need to analyse emissions throughout the whole
process of producing, transporting and using the
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fuel. Life-Cycle Analysis is the main tool used
to do this. It compares a specific biofuel system
with a reference system – in most cases petrol.
Greenhouse gas balances differ widely
depending on the type of crop, on the location,
on how feedstock production and fuel
processing is carried out. Biofuels from some
sources can even
generate more greenhouse gas emissions than
fossil fuels.
A significant factor contributing to greenhouse
gas emissions is the amount of fossil energy used
for feedstock production and transport,
including for fertilizer and pesticide
manufacture, for cultivation and harvesting of
the crops, and or in the biofuel production plant
itself.
Emissions of nitrous oxide are another important
factor. It is released when
nitrogen fertilizers are used and its greenhouse
gas effect is about 300 times stronger than that
of carbon dioxide.
By-products from biofuel production such as
proteins for animal feed make a positive
contribution to climate change mitigation
because they save energy and greenhouse gas
emissions that would otherwise have been
needed to produce the feed by other means.
ENVIRONMENTAL
IMPACTS
BIOFUEL PRODUCTION
OF
To assess the net effect on greenhouse
gas emissions of replacing fossil fuels by
biofuels, we need to analyse emissions
throughout the whole process of producing,
transporting and using the fuel. Life-Cycle
Analysis is the main tool used to do this. It
compares a specific biofuel system with a
reference system – in most cases petrol.
Greenhouse gas balances differ widely
depending on the type of crop, on the location,
and on how feedstock production and fuel
processing are carried out. Biofuels from some
sources can even generate more greenhouse gas
emissions than fossil fuels.
A significant factor contributing to greenhouse
gas emissions is the amount of fossil energy used
for feedstock production and transport, including
for fertilizer and pesticide manufacture, for
cultivation and harvesting of the crops, and or in
the biofuel production plant itself.
Emissions of nitrous oxide are another important
factor. It is released when nitrogen fertilizers are
used and its greenhouse gas effect is about 300
times stronger than that of carbon dioxide.
By-products from biofuel production such as
proteins for animal feed make a positive
contribution to climate change mitigation because
they save energy and greenhouse gas emissions
that would otherwise have been needed to produce
the feed by other means. Most studies have found
that producing first generation biofuels usually
yields reductions in greenhouse gas emissions of
20 to 60% when fossil fuels are replaced provided
the most efficient systems are used and carbon
dioxide emissions from changes in land-use are
excluded.
CHALLENGES
OF
BIOFUEL
POLICIES
Government incentives and support for
biofuel production and use have been largely
guided by national or regional interests rather than
a more global perspective. The desire to support
farmers and rural communities has been one of the
strongest drivers.
There is a need for a more consistent set of
policies and approaches, based on a clearer
understanding of the economic, environmental
and social implications, in order to balance the
potential and risks.
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These policies must be formulated in a situation
of considerable uncertainty.
fluctuating fossil fuel prices and on policy
developments.
o The exact role of biofuels in future global energy o
supplies is unknown. Yet even if the
contribution of biofuels to global energy supply
remains small, it may still imply a considerable
impact on agriculture and food security.
Technological developments may also influence
their profitability on the medium and long term.
For instance, commercial competitiveness of
second
o
The future economic viability of biofuels is
uncertain, because it depends on
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1. Evans, G. "International Biofuels Strategy
Project. Liquid Transport Biofuels Technology Status Report, NNFCC 08017", National Non-Food Crops Centre,
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supercritical water technologies". Energy &
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5. Ramirez, Jerome; Brown, Richard; Rainey,
Thomas (1 July 2015). "A Review of
Hydrothermal Liquefaction Bio-Crude
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Transportation Fuels". Energies. 8: 6765–
6794. doi:10.3390/en8076765.
6. National Non-Food Crops Centre. "NNFCC
Newsletter – Issue 19. Advanced Biofuels",
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7. National Non-Food Crops Centre. "Review
of Technologies for Gasification of Biomass
and Wastes, NNFCC 09-008", Retrieved on
2011-06-24
8. R. Inderwildi; David A. King (2009). "Quo
vadis biofuels?". Energy Environ. Sci. 2:
343346. doi:10.1039/B822951C. "Refuel.c
om biomethanol". refuel.eu.
generation biofuel technologies may significantly
improve the prospects for biofuel development.
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11.
12.
13.
14.
15.
16.
Knight, R. "Green Gasoline from Wood
Using Carbona Gasification and Topsoe
TIGAS Processes." DOE Biotechnology
Office (BETO) 2015 Project Peer Review
(24 Mar 2015).
Lu, Yongwu, Fei Yu, Jin Hu, and Jian Liu.
"Catalytic conversion of syngas to mixed
alcohols over Zn-Mn promoted Cu-Fe based
catalyst." Applied Catalysis A: General
(2012).
Quarderer, George J., Rex R. Stevens,
Gene A. Cochran, and Craig B. Murchison.
"Preparation of ethanol and higher alcohols
from lower carbon number alcohols." U.S.
Patent 4,825,013, issued April 25, 1989.
Subramani, Velu; Gangwal, Santosh K.; "A
Review of Recent Literature to Search for
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Larry Rother (2006-04-10). "With Big
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"EPA designates sugarcane ethanol as
advanced biofuel". Green Momentum.
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Archived from the original on 2011-07-11.
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Retrieved 2008-08-22. See
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Introduction (pp. 339-444) and Pillar I:
Innovation (pp. 445-482)
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Parametric study of Pump as Turbine-1: variation of speed
Doshi A. V.; Bade M. H.
Mechanical Engineering Department, SVNIT, Surat, Gujarat, India-395007
Corresponding Author: avdoshi2001@gmail.com
Abstract
Pump operated in reverse mode (PAT) are popular for remote energy source where energy is required
mainly for lighting during night hours and may used for local industry during day. However, in Indian
situation, flow rate of available water streams are higher in rainy season and reducing toward summer.
If speed of PAT is constant then there is significant loss in efficiency due to reduction in flow rate.
However, operating the PAT at variable speed, efficiency loss may be significantly reduced. In this
paper, simple approach based on characteristics of pump operated in reverse mode and affinity law
is used to evaluate the best efficiency point at variable speed conditions.
Keywords: Pump as turbine, reverse mode operation of pump, affinity law
1.
Introduction
Energy is necessary for holistic development
of society and need to be provided to everyone
irrespective of paying capacity. Considering
challenges of use of fossil fuels such as
pollution mainly due to emission of flue gases,
climate change due to global warming, etc.,
renewable energy sources are only the
potential source for sustainable development
(Derakhshan and Nourbakhsh 2008). Among
various renewable energy sources, microhydro power plants are gaining special
attention if natural streams are available due to
its continuous and reliable feature.
Additionally, remote areas which are far away
from gridlines, isolated power systems such as
micro-hydro power plants are popular, which
may take local industrial load during day time
and provide electricity for lighting at night
hours (Williams 2003). For implementation of
micro-hydro power plants major cost is for
water turbine, as it need to be designed and
developed in meagre quantity. To overcome
this issue pump as turbine (PAT) is in use since
pumps are mass manufactured and are robust
in design as well as construction. Being pump
is not manufactured as turbine, it lacks
governing mechanism resulting in lower
efficiency at part load and over load conditions
except best efficiency point (Yang et al. 2012).
However, it is always difficult to match best
efficiency conditions at field operations due to
various influencing factors for efficient
operation of PAT. For Indian continent, during
monsoon availability of water flow rate and
head is very high, but it decreases towards the
summer and becomes minimum at start of
monsoon. So designing the PAT for variable
flow conditions so that it will give maximum
efficiency is essential. Fernandez et al.
(Fernández et al. 2004) presented parametric
study on a centrifugal pump used as a turbine
at various rotational speeds. However, they felt
that in order to predict the turbine
characteristics accurately it is necessary to
analyze statistically more test data to arrive
good relations. Yang et al. (2012) carried out
experimental work on single stage centrifugal
pump operated as a turbine at different
rotational speeds (1000, 1200, 1500 and 1800
rpm). Additionally, experimental results are
validated with computational work showing
agreement and they have concluded that it is
more suitable to select a small PAT at large
capacity, so that its efficiency will not drop
rapidly or become energy-consuming device
as flow rate fluctuates. Caravetta et al.
(Carravetta et al. 2014) studied the affinity law
for the evaluation of the behaviour of a single
machine under variable speed. They selected a
large database of experimental curves of
several PATs (17 PATs) operated at different
speeds and compared the experimental data
with the results of the application of the
affinity law. Further it is concluded that the
error in the evaluation of efficiency was less
than 15 % for velocities varies from −40 % to
+50 %. Jain et al. (2015) carried out
experimental investigations on centrifugal
pump running in turbine mode to optimize its
operational parameter by varying from 900 to
1500 rpm. The performance of PAT was found
better at the lower speeds than that at the rated
speed. Ismail et al. (2016) conducted study of
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PAT to simulation analysis of the effect of
rotational speed on PAT’s performance curve
over a range of flow rates using numerical tool.
Wang et al. (2016) compared the results
obtained by the experiment and by theoretical
calculation and observed deviation between
them at of best efficiency point for different
rotational speed.
1.1
Objectives of the Current Study
Based on the above-mentioned literature
review and available experimental facility in
the laboratory, the following objectives have
been planned:
i. To operate a selected pump in reverse
mode (PAT) and to obtain it’s
performance characteristic at various
speeds.
ii. To find out the optimal operating point
(best efficiency point) based on
experimental work at various speeds for
recommendation of applicability of PAT
under various flow conditions.
iii. To compare the obtained experimental
results of PAT with that of the results
deduced by affinity law
2.
Means of solutions:
The methodology applied for achieving above
objectives are experimental investigations and
theoretical analysis.
2.1
Experimental Investigation
A radial flow type centrifugal pump with the
specifications shown in Table 1 is selected to
operate as turbine in the test rig (shown in
Figure 1). The main components in the PAT
test rig are feed pump, piping system, test bed,
draft tube, eddy current dynamometer, etc. The
high end measuring devices such as pressure
transmitters, magnetic flow meter, speed
sensors, and torque sensor are employed.
Detailed description of this PAT test rig is
given by Doshi (2017). The PAT is tested for
three different speeds (800 rpm, 900 rpm, and
1000 rpm) and appropriate data is recorded
using PLC and SCADA system. This data is
processed to plot various characteristic curves
such as head Vs. flow rate, power Vs. flow rate
and efficiency Vs. flow rate
2.2
Theoretical Analysis of PAT
To evaluate PAT parameters at BEP for
different speeds, affinity laws are applied. The
affinity laws express the mathematical
relationship between the variables of PAT at
BEP for different speeds when its diameter is
kept constant. These relations are applicable to
all class of turbomachines. For small variation
of speed of PAT (with constant diameter),
variation in different efficiencies such as
volumetric, hydraulic and mechanical
efficiencies are very small. In addition,
velocity triangles at inlet and outlet are
assumed to be similar. Therefore, the
simplified affinity laws for PAT variables at
BEP are:
Q1 n1
Q2 n2
(1)
2
H1 n1
H2 n2
(2)
3
P1 n1
P2 n2
(3)
Figure 2 shows velocity triangles at the inlet
and exit of the runner blade of a PAT. The
relationship between theoretical parameters of
PAT can be expressed in terms of different
components of velocity triangles. Using
momentum theorem and turbine inlet and
outlet velocity triangles, Euler head in turbine
mode is represented as:
(4)
H =
Additionally, for steady state, theoretical flow
rate through PAT is given by following
equation:
Q = πD B C
= πD B C
(5)
Furthermore, shaft power is expressed as:
P = ρgQH ∗ η ∗ η ∗ η
(6)
3 Results and Discussions:
The data generated by running the same PAT
at speed of 800 rpm, 900 rpm and 1000 rpm
with help of experimental test rig and
evaluated various parameters such as flow rate,
head, power, and efficiency. These parameters
are shown in the form of characteristic curves
as head, power and efficiency Vs. flow rate in
Figures 3, 4, and 5.
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In the plot of head Vs. discharge (Figure 3),
higher speed curve is above that of lower
throughout part load to overload region. The
plots are diverged at part region and
converging towards overload region. This
indicates that higher head is required to operate
the PAT at high speed in part load region and
for over load region, it is almost converged.
The second characteristic curve (Figure 4)
indicates that output power at part load is close
and diverging towards overload region for
given speeds. At higher operating speed of
PAT, power output in overload region is also
higher. The efficiency curve shown in Figure 5
for speeds 800 rpm, 900 rpm and 1000 rpm
indicate that at duty point efficiency of PAT is
maximum, in part load, and overload region is
dropping. In part load region, the efficiency
curve is steep whereas in overload region slop
of drop in efficiency curve is comparatively
small. With increasing in the speed of PAT, it
is observed from Figure 5 that the peak
efficiency (BEP) is shifting towards higher
flow rate. Further, this helps in operation of
PAT where flow rate is reduced. If flow rate is
dropped down, then it is always advantageous
to operate PAT at lower speed than the speed
at which it is running such that it’s operating
point for new condition will match with the
duty point.
Table 2 presents the performance parameters at
BEP determined by experiment and by affinity
law. The difference between them is negligible
as speed range is also comparative small
indicating that for small speed range, affinity
law held good at BEP. Further, in the given
speed range, peak efficiencies are also close as
all losses are nearly same and there is
similarity in velocity triangles.
4 Conclusions:
In the paper, the state of art facility is
developed for testing the PATs with high-end
instrumentation and automatic control
systems. Based on PAT characteristic curves
obtained at various speed, PAT can be
operated optimally (without much compromise
of reduction in efficiency) to meet with
variable flow conditions. For low range of
speed variations, the affinity law held good and
can be used to predict the PAT performance
parameters mainly at BEP. Testing of affinity
law at high-speed range with large data can be
future scope of work. This will increase the
applicability of PAT for variable speed
operation.
Nomenclatures:
B
C
D
g
acceleration, m/s2
h
H
n
P
Q
u
velocity, m/s
w
Greek Symbols
α
β
η
ρ
ω
Impeller width, m
Absolute velocity, m/s
Impeller diameter, m
Gravitational
Head, m
Net head, m
Rotational Speed in rpm
Power, kW
Discharge, m3/s
Tangential
blade
Relative velocity, m/s
Absolute flow angle, °
Blade angle, °
Efficiency, %
Mass density, kg/m3
Angular velocity, rad/s
Abbreviations
PLC
Programmable Logic
Controller
rpm
revolution per minute
SCADA
Supervisory
Control
And Data Acquisition
Subscripts
1
mode)
2
mode)
h
m
v
u
Impeller inlet (Turbine
Impeller exit (Turbine
Hydraulic
Mechanical
volumetric
Tangential component
References:
1. Carravetta, A., Conte, M.C., Fecarotta, O.,
and Ramos, H.M., 2014. Evaluation of
PAT performances by modified affinity
law. Procedia Engineering, 89, 581–587.
2. Derakhshan, S. and Nourbakhsh, A.,
2008. Experimental study of characteristic
curves of centrifugal pumps working as
turbines in different specific speeds.
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3.
4.
5.
Experimental Thermal and Fluid Science,
32 (3), 800–807.
Doshi, A., 2017. Influence of Inlet
Impeller Rounding and the Shape of NonFlow Zones on the Performance of
Centrifugal Pump As Turbine. Sardar
vallabhbhai
National
Institute
of
Technology, Surat, India.
Fernández, J., Blanco, E., Parrondo, J.,
Stickland, M.T., and Scanlon, T.J., 2004.
Performance of a centrifugal pump
running in inverse mode. Proceedings of
the Institution of Mechanical Engineers,
Part A: Journal of Power and Energy, 218
(4), 265–271.
Ismail, M.A., Othman, A.K., and Zen, H.,
2016. Numerical Investigation of
Rotational Speed on Pump as Turbine for
Microhydro
Applications.
Applied
Mechanics and Materials, 833, 11–18.
6.
7.
8.
9.
Jain, S. V., Swarnkar, A., Motwani, K.H.,
and Patel, R.N., 2015. Effects of impeller
diameter and rotational speed on
performance of pump running in turbine
mode.
Energy
Conversion
and
Management, 89, 808–824.
Wang, T., Kong, F., Chen, K., Duan, X.,
and Gou, Q., 2016. Experiment and
analysis of effects of rotational speed on
performance of pump as turbine.
Transactions of the Chinese Society of
Agricultural Engineering, 32 (15), 67–74.
Williams, A.A., 2003. Pumps as Turbines
A user’s guide. 2nd Ed. Warwickshire,
UK: Practical Action publishing.
Yang, S.S., Kong, F.Y., Jiang, W.M., and
Qu, X.Y., 2012. Research on rotational
speed to the influence of pump as turbine.
IOP Conference Series: Earth and
Environmental Science, 15 (4), 42023.
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List of Figures:
Figure 1: Schematic Layout of PAT Test Rig
(Doshi 2017)
Figure 2: Velocity triangles at inlet and outlet
of PAT
Figure 3: Head Vs. Flow Rate characteristic
curves for PAT at different speeds
Figure 4: Power Vs. Flow Rate characteristic
curves for PAT at different speeds
Figure 5: Efficiency Vs. Flow Rate
characteristic curves for PAT at different
speeds
25
800
RPM
20
Head (metre)
15
10
5
0
0
5
10
15
Flow rate (lpm)
20
25
Figure 3: Head Vs. Flow Rate characteristic
curves for PAT at different speeds
3
800
RPM
2.5
ElectroMagneticFlowM
eter ControlValve
Power (kW)
2
1.5
Pressure
Guages
VFD
Panel
FeedPump
EddyCurrent
Dynamometer
Conrtol
Panel
G.L.
TorqueSensor
Pressure
Guages
0.5
PAT
0
0
M
otor
Ground
level
1
TestBed
Draft
Tube
Comm
onSump
Ground
level
10
15
Flow rate (lps)
20
25
Figure 4: Power Vs. Flow Rate characteristic
curves for PAT at different speeds
70
800
RPM
60
50
Efficiency (%)
Figure 2: Schematic Layout of PAT Test Rig
(Doshi 2017)
5
40
30
20
10
0
0
5
10
15
20
Flow rate (lpm)
25
Figure 5: Efficiency Vs. Flow Rate
characteristic curves for PAT at different
speeds
Figure 2: Velocity triangles at inlet and outlet
of PAT
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List of Tables:
Table 1: Pump specifications selected for reverse mode operation
Table 2: Comparison of experimental and analytical parameters at BEP
Table 1: Pump specifications selected for reverse mode operation
Property of centrifugal
Value
pump
Head (bep)
20.4 m
Flow rate (bep)
17.5 lps
speed
1450 rpm
Efficiency (bep)
64 %
Impeller diameter
0.260 m
Number of blades
6
Table 2: Comparison of experimental and analytical parameters at BEP
Speed
rpm
Flow Rate
lps
800
900
1000
13.51
14.95
16.77
Head, (m)
Efficiency (η)
%
Experiment Affinity
62.75
62.71
63.35
10.73
13.36
16.67
13.58
16.76
Power, (kW)
Experiment
Affinity
0.892
1.228
1.737
1.27
1.742
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Performance Analysis of a Low Price Thermoelectric Cooler: An
Experimental Approach
Shiv Lal1, Emarti Kumari2
of Mechanical Engineering, Rajasthan Technical University Kota 324010, India
2Department of Mechanical Engineering, Poornima Groups of Institutions, Jaipur, 302022, India
Corresponding Author: shivlal1@gmail.com , +91-9636855553
1Department
Abstract
In this communication, performance analysis of thermoelectric refrigerator is carried out. The
thermoelectric refrigerator is developed in the laboratory and onsite experimental work has been
done. The complete system cost is very low approximately 49.66 USD. The COP is varying from
0.17 to 0.26 at different cooling load condition and the lowest temperature can be achieved 2.3 C to
10.5°C without load and full load within 28 minutes, respectively. The material research and
cascading of the modules are required to increase the cooling effect as well as capacity of the
refrigerator.
Key word: Refrigerator; Peltier-Seebeck effect; Thermo-Electric Refrigerator (TER)
1.
Introduction
In present era a new technology is required to
meet the refrigeration load of the world, to
minimize the utilization of CFC and HFC’s for
eco-friendly concern. Peltier effect and
Seebeck effect were first discovered to present
in metals as early as 1820s–1830s [1]. Beitner
[2-3] proposed a simple design of
thermoelectric module which can produce
heating effect at one side and cooling effect at
another side. Reed and Hatcher [4] introduced
a fan to enhance the heat dissipation at hot side
of TER. The super insulation material and
phase change material were introduced by Park
[4-5], these materials improved the energy
efficiency of the system and extended the time
period. Guler and Ahiska [7] experimentally
investigated the performance of a portable
TER medical cooling kit. Chen [8] analysed
the heat transfer rate and efficiency of TE
(thermoelectric) cooling systems, and
observed a low efficiency.
The purpose of a TER is to maintain the
junction temperature of an electronic device
below a certain temperature by removing heat
from the device [9]. Peltier cooling appliances
can provide rapid cooling. For example, a solar
Peltier refrigerator is capable for reducing the
temperature from 27 °C to 5 °C in about 44
minute. TER is a light, rugged, reliable and
noiseless medical cooling kit.
Dai et al. [10] proposed the merits of
the TER as follows: light, reliable, noiseless,
rugged and low cost in mass production, uses
electron rather than refrigerant as heat carrier,
low starting point and it is feasible to be used
solar cells. Astrain et al. [11] developed a
computational model based on finite difference
method to simulate the thermal and electric
performance of thermoelectric refrigerator.
Author was observed that thermoelectric
refrigerator is more ecological, silent and
robust as compare to vapour compression
cycle-based refrigerator.
Sabah et al. [12] built an affordable
solar thermoelectric refrigerator for the desert
people of remote area of Oman. That was
designed to store and transport the biological
material and medications. Author was stated
that TER can reduce the temperature of water
from 27 C to 5 °C within 44 minute, evaluated
the COP of that TER was 0.16. Putra [13]
designed, manufactured and tested a portable
vaccine carrier box employing thermoelectric
module and heat pipe. The heat pipe is working
as a heat sink when it fixed at hot side of the
TER, it was reported that by heat pipe cooling
performance found better than without heat
pipe. The temperature in the vaccine carrier
has reached up to -10 °C within a hour. It
shows that the vaccine carrier can store
medicine at any desired temperature. Adeyanju
et al. [14] theoretically and experimentally
compared the chilling time of water between
freezer space of conventional house hold
refrigerator and beverages TER and observed
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that
the
TER
reduces
temperature
exponentially to time as compared to
conventional VCR varies linearly. TER gives
the fastest cooling as compared to
conventional refrigerator. Gillott et al. [15]
experimentally investigated a thermoelectric
cooling (TEC) devices built in laboratory for
small-scale space conditioning applications in
buildings. They were find out an optimum
solution for operating the TEC. The COP of the
TEC was observed by 0.45 for cooling effect
of 200 W for which the input current supplied
by 4.8A for each module.
Thermoelectric refrigerators applications are
concerned
with environment
friendly
refrigeration in electronic industry, medical
services, space applications, milk industry,
transportation tools, and military devices [16].
TER refrigeration devices are a low cost in
mass production if charge carriers in the
thermoelectric material are used rather than
refrigerant as the heat dissipation carrier. Zhou
and Yu [2012] presented a generalized
theoretical model for the optimization of a
thermoelectric cooling system. Their analysis
showed that the maximal COP and the
maximal cooling capacity can be obtained
when the finite thermal conductance is
optimally allocated.
Ranjana et al. [17] experimentally
studied the thermoelectric cooler driven by
photovoltaic system. They determined that the
unit can maintain 10-15 degree Celsius
temperature and revealed COP was 0.34.
Authors also stated that the performance of the
system is function of solar insolation rate and
temperature difference of hot and cold sides of
TE modules. Researchers also designed it for
personal cooling like for electronic cooling
[18]. Twaha et al. [19] reviewed the TER /
TEG technology for application, modelling
and performance improvement. Hence, to
reduce the power consumption rate in urban
area; to improve the leaving life of rural area
and to save the deteriorating environment due
to various refrigerants (CFC and HFC) more
research work is required for thermo electric
refrigerators / coolers.
In this paper, authors have developed a
thermo electric refrigerator / cooler that is
operated by solar cells. It is also determined the
cooling capacity and coefficient of
performance of the developed refrigerator.
This system is suitable in rural areas for
storage of food and vaccines. So, more
experimental and numerical analysis are
required for acceptance of this technology.
2.
Materials and Methods:
The experimental set-up is developed
in Laboratory of Department of Mechanical
Engineering, Poornima Groups of Institutions,
Jaipur [Latitude and Longitude 26° 55' 19" N,
75° 46' 43" E]. The various parts like Peltier
principle base TER, Ice box, fan, heat sink is
used and observations have been taken for one
hour.
2.1
Experimental Set-up:
Thermoelectric cooling uses the Peltier
effect to create a heat flux between the
junctions of two different types of materials. A
Peltier cooler / heater / thermoelectric heat
pump is a solid-state active heat pump as
shown in Figure 1, which transfers heat from
one side of the device to the other, with
consumption of electrical energy, depending
on the direction of the current. Thermoelectric
Peltier Modules are used in various
applications where electricity is not reached at
now, and it runs by solar panel: Water
Machines, Medical Equipment, Cooling boxes
and small fridges, Massagers, Electronic Parts
cooling (Processors, Integrated circuits) and
many more.
Fig. 1 Principle of Thermoelectric Refrigerator
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The experimental set-up was built in
the Laboratory of college; it consists with a
Peltier module TEC1-12706, Battery, Cooling
fan, heat sink and a cooling box. The
construction detail of module is shown in
Figure 2. and specifications are shown in Table
1.
Fig. 3: Nomenclature of Thermoelectric
Cooler Module
The Cooling box / freezing box is made
by thermocol, and the box outer size 200 200
200 mm and inner size is 170 170
170mm. The Properties of thermocol are:
Table 2: Properties of thermocol
Fig. 2: Schematic diagram of Thermoelectric
Cooler Module (TEC1-12706), Solder
Construction: 138°C, Bismuth Tin (BiSn)
Table 1: Specification of TER module
Mode
l No.
TEC1
1270
6
Th=30°C
Imax,
Am
p
Tmax
, °C
6.0
≥67
Measurements
W,
L,
T
in mm
Vma
x,
Volt
x,
15.0
51.4
S.
No.
1
Types of Properties
Properties
Thermal conductivity at
10°C mean temperature
2
3
4
5
6
Compressive strength
Cross breaking strength
Tensile strength
Application range
Water absorption by %
volume for 7 days in
water
Self-ignition point
Melting point
0.028-0.031
Kcal-m/hr. m2
.°c
0.8-1.6 Kg/cm2
1.4-2.0 Kg/cm2
3-6 kg/cm2
-200 +80 °C
0.5%
Qma
W
40
40
3.6
The following safety features have
been used for using TEC module: Heating or
cooling with the same module is possible
simply by reversing polarity. Lettered side of
modules are the “hot side”. Do not attempt to
use TEC1 Peltier Modules without a fan or
liquid cooled heat sink. Due to extreme ∆𝑇
temperature differentials, module damage, fire,
or operator injury can occur when sufficient
thermal resistance is not present.
The nomenclature of the module is
clearly indicating system configuration as
shown in Figure 3.
7
8
300 °C
100 - 200 °C
A complete assembly of TER is shown
in Figure 4 with module, fan and heat sink. All
the specifications of TER module is presented
above, whereas the ADDA make cooling fan
operating at 20A and 0.20A DC power. The 40
40 mm aluminium heat sink is used to
dissipate the hot side heat into atmosphere. The
Complete assembly is fastened with the help of
steel screws. A luminous make battery is used
to supply the DC power to the TER unit, which
shown in Figure 5. A charger is also used
before the battery for continuously charging
the battery, whereas AC power is supplied to
the system through charger. The parts of the
TER system are purchased from market by
49.66 USD.
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(d)TER pannel assembly.
(a)TEC1-12706 module
Figure 4.. TER Pannel assembly with module,
fan, and heat sink
Fig. 4 Photo of Experimental Thermoelectric
Refrigerator
(b)Cooling Fan
(c)Heat Sink with Fins
2.2
Mathematical Modelling:
The proposed methodology for performance
analysis by Riffat and Ma [1] is used to evaluate
the COP of the thermoelectric cooler. The
thermoelectric cooler is working on Peltier effect,
where the thermoelectric cooling effect is given by,
Q = αIT
(1)
Where, α is the average Seebeck coefficient of the
thermoelectric material, I is current supplied to the
couple, and Tc is the cold junction temperature in
°C.
The current flow is producing resistive or Joule
heating in the thermoelectric material. The Joule
heating is given by,
Q =I R
(2)
Where, R is the resistivity of the couple.
The heat is conducted for hot end to the cold end
through the thermoelectric material during
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Where k is the thermal conductivity of
thermocouple, and h & c indicates the hot and cold
ends. The above equation (3) indicates that Q
increases with increases the temperature difference
across the couple. For the energy balance equation,
combining equation (1), (2) and (3) as given by
Q = Q − 0.5Q − Q
Q = αIT − 0.5I R − k∆T
(4a)
(4b)
Above equation (4) is the standard equation for
evaluating the cooling effect. The electrical energy
consumed by the TER can be estimated by
Q = I R + αI∆T
(5)
Where, I is the current. The Coefficient of
Performance (COP) of the TER can be calculated
by dividing the equation (4) and (5), and we get
COP =
.
=
∆
∆
(6)
By solving above equation for condition
= 0,
Current can be optimised and for optimum current
optimum COP can be estimated. The final
equations for Optimum current and optimum COP
is given by,
observed for without load condition such as 2.3
°C and maximum temperature for 600 ml
loading is found to be 10.5 °C.
35
30
Room
Temperatu
re
25
Temperature, °C
operation; this rate of conductive heat can be
evaluated by
Q = k (T − T ) = k∆T
(3)
200 ml
water load
20
15
10
5
0
0 2 3 4 5 6 7 8 9 11121314151617192021222324252728
Time, Minute
Fig. 5. Performance of TER on April 3, 2017
(Operating on conventional energy)
Where, 𝑍 =∝ /𝑘𝑅, Z is the figure of merits
and it depends on the properties of the material.
It should be higher for maximum COP of TER.
The cooling rate is very high and
capacity of the module is low. For increasing
the cooling capacity, number of panel can be
fitted in the cooling box / refrigerator. The
COP of the TER system is very low and it
observed by 0.26, 0.22, 0.18 and 0.17 for
without cooling load and with 200, 400, 500 ml
water cooling load, respectively. TER run by
conventional electricity is not feasible at now
but for small cooling like for electronic cooling
it is acceptable and found suitable option. TER
can be run on solar cell. The solar energy is
available freely and in abundant quantity. The
cost of the complete system is estimated by
49.66 USD (1 USD = 64.44 Rs as dated on
June 2, 2017).
3.
4.
𝐼
=
∆ /
(7)
By outing the value of I in equation (6) and we
get,
𝑐𝑜𝑝 = (
)
(8)
Results and Discussions
The experimental work for TER was
carried out for operating on conventional
energy on April 3, 2017. The Figure 6 shows
the variation of temperature with respect to
time at different-different conditions such as
without cooling load, with 200, 400, 600 ml
water cooling load. Initial condition for all
loading conditions is same as at 30.9 °C and
the minimum temperature after 28 minute is
Conclusions
Thermoelectric refrigerator is new and
renewable technology for the scientific
community; so many researchers are doing
their work on improving the performance of
TER. It can be possible only due to increasing
the value of figure of merit of thermoelectric
material. The performance analysis has been
carried out with the experimental observations
at Jaipur India. It is concluded that lowest
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temperature for without cooling load to 600ml
cooling load have been achieved by 2.3°C and
10.5°C for the interval of 28-minute time. The
COP of the system is estimated by 0.22, 0.18
and 0.17 for without cooling load and with
200, 400, 500ml water cooling load
respectively. The system cooling effect can be
increased by cascading of the module and by
putting the number of module at different
places on the sides of the Refrigerator. It can
be run by solar energy, means its application
can be widely increases up to interior areas of
the country, where no conventional electricity
till now.
Nomenclature:
COP Coefficient of Performance
Current (A)
I
thermal conductivity of
k
thermocouple (W m-K_1)
electrical resistivity of the
R
thermocouple (VA_1)
Cold side Temperature ( °C)
T
Hot side Temperature ( °C)
T
DT temperature difference between hot
and cold end (8C)
heat flow at cold side (W)
Q
heat conduction from the hot end to
Q
cold end (W)
electrical energy consumption by
Q
the module, W
heat flow at hot side (W)
Q
joule heat generation rate (W)
Q
Peltier heat pumping rate (W)
Q
Seebeck coefficient of
α
thermoelectric material (W/A-K)
References:
1. Riffat S. B. and Ma X., “Thermoelectrics:
a review of present and potential
applications,”
Applied
Thermal
Engineering, vol. 23, no. 8, pp. 913–935,
2003, DOI: 10.1002/er.991
2. Beitner S, Hand case, Patent No. US
4089184A, Publication date May 16,
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3. Beitner S, Thermoelectric cooler, patent
no. US 4627242A, Publication date Dec 9,
1986,
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4. Reed K L H, Hatcher, I Compact
thermoelectric refrigerator, patent no. US
4326383A, publication date April 27,
1982,
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US4326383
5. Brian V. Park, Austin; Malcolm C. Smith,
Jr., La Porte, both of Tex.; Ralph D.
McGrath, Granville, Ohio; Michael D.
Gilley, Rowlett, Tex.; Lance Criscuolo,
Dallas, Tex.; John L. Nelson, Garland,
Tex. Patent no. 5,522,216, Publication
date June, 4, 1996.
6. Barako M T; Park W; Marconnet A M;
Asheghi M; Goodson K E, Thermal
Cycling, Mechanical Degradation, and the
Effective Figure of Merit of a
Thermoelectric Module. Journal of
Electronic Materials; Warrendale 42 (3 )
(Mar
2013):
372-381.
DOI:
10.1007/s11664-012-2366-1.
7. Guler N F, Ahiska R, Design and testing
of a microprocessor-controlled portable
thermoelectric medical cooling kit.
Applied Thermal Engineering 22 (2002)
1271–1276,
DOI:
10.1016/S13594311(02)00039-X.
8. Chen, K. and Gwilliam, S. B. (1996), An
analysis of the heat transfer rate and
efficiency of TE (thermoelectric) cooling
systems. Int. J. Energy Res., 20: 399–417.
doi:10.1002/(SICI)1099114X(199605)20:5.
9. Chein R, Huang G. Thermoelectric cooler
application in electronic cooling. Applied
Thermal Engineering 2004; 24(14–
15):2207–17.
DOI:
10.1016/j.applthermaleng.2004.03.001
10. Dai Y. J., Wang R. Z., and Ni L.,
“Experimental investigation and analysis
on a thermoelectric refrigerator driven by
solar cells,” Solar Energy Materials &
Solar Cells, vol. 77, no. 4, pp. 377–391,
2003.
DOI:10.1016/S09270248(02)00357-4.
11. Astrain D., Vian J.G., and Albizua J.
(2005), Computational model for
refrigerators based on Peltier effect
application.
Applied
Thermal
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12.
13.
14.
15.
Engineering. 25, 3149-3162. DOI:
10.1016/j.applthermaleng.2005.04.003.
Sabah A. Abdul-Wahab, Sabah A. AbdulWahab, Ali Elkamel, Ali M. Al-Damkhi,
Is’haq A. Al-Habsi, Hilal S. Al-Rubai’ey,
Abdulaziz K. Al-Battashi, Ali R. AlTamimi,
Khamis
H.
Al-Mamari,
Muhammad U. Chutani . Design and
experimental investigation of portable
solar
thermoelectric
Refrigerator.
Renewable Energy 2009; 30; 30–34. DOI:
10.1016/j.renene.2008.04.026.
Putra N., 2009, “Design, manufacturing
and testing of a portable vaccine carrier
box employing thermoelectric module and
heat pipe”, Journal of Medical
Engineering & Technology, 33 (3): 232237, DOI: 10.1080/03091900802454517.
Adeyanju A.A., E. Ekwue and W.
Compton, 2010, “Experimental and
Theoretical Analysis of a Beverage
Chiller”, Research Journal of Applied
Science, 5 (3): 195-203, DOI:
10.3923/rjasci.2010.195.203.
Gillott Mark, Liben Jiang and Saffa Riffat,
2010, “An investigation of thermoelectric
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conditioning applications in buildings”,
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34, (9): 776–786, DOI: 10.1002/er.1591.
16. Zheng XF, Yan YY, Simpson K. A
potential candidate for the sustainable and
reliable domestic energy generationthermoelectric cogeneration system.
Applied Thermal Engineering 2013;
53(2):
305–11,
DOI:
10.1016/j.applthermaleng.2012.03.020.
17. Ranjana H., Kaushik S C, Manikandan S.
Experimental Study and Analysis on
Novel Thermo-Electric Cooler Driven by
Solar Photovoltaic System. Applied Solar
Energy, 2016, Vol. 52, No. 3, pp. 205–
210. DOI: 10.3103/S0003701X16030063.
18. Zhou Y, and Yu J., “Design optimization
of thermoelectric cooling systems for
applications in electronic devices,”
International Journal of Refrigeration, vol.
35, no. 4, pp. 1139–1144, 2012. DOI:
10.1016/j.ijrefrig.2011.12.003.
19. Twaha S, Zhu J, Yan Y, Li B. A
comprehensive review of thermoelectric
technology:
Materials,
applications,
modelling and performance improvement.
Renewable and Sustainable Energy
Reviews 65 (2016) 698–726, DOI:
10.1016/j.rser.2016.07.034.
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Transcritical CO2 Based Dedicated Mechanial Sub Cooling VCR System: A
Review
Neetu Kumari, Amit Sharma
Department of Mechanical Engineering
Deenbandhu Chhotu Ram University of Science and Technology
Corresponding Author: kneetu50@gmail.com , amitsharma.me@dcrustm.org
ABSTRACT
Use of synthetic refrigerants is restricted under several agreements because of their detrimental effect on
our environment. Owing to the fact, that they have high global warming potential (GWP) and ozone
depletion potential (ODP). So again, carbon dioxide is gaining popularity in the areas of refrigeration
and air conditioning because of its eminent properties as a refrigerant. In this paper we are presenting the
investigation of the performance of transcritical CO2 in the Indian conditions so that further scope of
using carbon dioxide as a refrigerant increase in the future. India has a vast assortment of climates ranging
from tremendously hot desert regions to high altitude sites with extremely cold conditions. And it is also
proved by researchers that after some modifications transcritical CO 2 may provide better results as
compared to the synthetic refrigerants. However, there is a very wide gap in using CO 2 in applications
due to less research was done in this area, especially in Indian context.
Keywords: - Natural Refrigerants, CO2, Transcritical, Dedicated Mechanical Subcooling
.
Looking at it, we are again turning towards
INTRODUCTION:
natural refrigerants and CO2 being a natural
Carbon dioxide (CO2) was the first refrigerant
refrigerant is a best supplement because of its
ever used in refrigeration systems and till the
excellent properties as a refrigerant. It can be
1930; almost 80% of marine applications were
extracted from environment economically as
using CO2 as a refrigerant. With introduction of
well as it is safe (zero ODP and low GWP),
CFCs (nontoxic, nonflammable and operated
nontoxic, non-flammable and environmentefficiently over a range of temperatures) [1] in
friendly, high volumetric capacity lower
1950, there is a sharp decline in uses of CO2,
compressor ratio and exonerated thermo
because of its high operating pressure. From
physical properties [2]. It is an inert gas, perfect
1950 onwards, CO2 has been completely
for every normal material experienced in a
replaced by CFCs. CFCs were restricted under
refrigerating circuit, both metals and plastics.
Montreal protocol because of their high ozone
And its credit goes to professor Gustove, who
depletion potential (ODP). Consequently, CFCs
was the first to draw the attention towards the
replaced by HCFCs which have an ozone
use of CO2 and he also eliminates the problem
depletion potential to a less extent. But HCFCs
that was occurred with the transcritical CO2
also banned during under Montreal Protocol,
subcritical system operating with heat rejection
which results introduction HFCs, which do not
temperature in the vicinity of critical point in his
have ODP but having high global warming
patent [3] application for a CO2 transcritical
potential(GWP). Therefore, they are restricted
cycle for automotive air conditioning system.
under the Kyoto Protocol. In 2015, European
CO2 has low critical temperature (30.98°C),
Union (EU) made a new regulation by which all
which causes it to operate in transcritical
the Fluorinated greenhouse gases will be phased
conditions.
However,
in
transcritical
out by 2030 with GWP greater than 150 from
refrigeration system heat rejection takes place
mobile air conditioning systems.
above the critical point of CO2. That’s why in the
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transcritical carbon dioxide cycle we make use
of gas cooler instead of condenser. Because at
high temperatures carbon dioxide becomes
dense and it is not possible to reject heat in the
condenser, so we use gas cooler instead of
condenser. And it operates at very high pressure
that’s major problem with this cycle. Many
efforts have been done to enhance the
transcritical carbon dioxide cycle so that it can
give equal or more efficiency than synthetic
refrigerants give. Transcritical CO2 cycle gives
appreciable performance in the cold regions. But
the performance of gas cooler is highly sensitive
to operating temperature and pressure for
tropical or Indian climatic conditions (where the
ambient temperature is higher) [4], so
modification is necessary to improve the
coefficient of performance (COP) of the
transcritical cycle. And various techniques were
applied by many researchers to modify the
performance of transcritical CO2 refrigeration
cycle. An experiment was performed using
internal heat exchanger in a transcritical CO2
refrigerator to improve the efficiency of the
single stage system [5]. Sarkar et al [6] and Bell
et al [7] shows that COP of transcritical cycle for
warm climates can be enhanced by employing
parallel compression. Sarkar [6] employed a
parallel compression economization, is a process
of improving the performance of transcritical
CO2 refrigeration cycle. in which refrigerant
vapor is compressed up to supercritical
discharge pressure in two different non-mixing
streams. As shown in fig.1 ,one stream coming
from economizer (at point 8) , another stream
from evaporator (at point 2) and goes to gas
cooler. COP of transcritical CO2 cycle will be
optimum at combination of specific operating
parameters purposed by Kim et al. [2]. Winkler
et al. [8] proposed that by incorporating
thermoelectric subcooler as a dedicated
subcooler at the exit of a gas cooler of a
transcritical CO2, which increases the COP by
16% and cooling capacity by 20%, even after
external power consumption taken into account.
Sarkar [9] showed the increase in COP,
volumetric cooling capacity and decrease in high
side pressure, compressor pressure ratio and
compressor discharge temperature with the use
of thermoelectric subcooler in the transcritical
CO2 refrigeration system. Aklilu Tesfamichael
et al.[10] studied transcritical CO2 refrigeration
cycle by making a model and simulated at
different operating parameters. And found that
the cycle pressure (corresponds to maximum
COP) is depends on gas cooler exit temperature
and evaporator temperature and cycle was more
suitable for air conditioning than refrigeration.
Dubey et al. [11] studied the transcritical
CO2/propylene (R744–R1270) cascade system
for cooling and heating applications and found
that transcritical CO2-propylene is better than
N2O-CO2, CO2-propane and subcritical cascade
cycles in terms of COP. The maximum COP
increases with the increase in evaporator exit
temperature, but decreases as gas cooler exit
temperature. Rawat et al. [12] demonstrated that
COP of transcritical carbon dioxide system
increases with a decrease in gas cooler inlet
temperature of external fluid and increase in
evaporator temperature and not affected by the
effectiveness of internal heat exchanger.
Exergy Study :
Yang et al. [13] found that transcritical CO2
cycle with expander has 33% more COP and
30% more exergy efficiency than the throttling
valve cycle. And largest exergy loss occurs at
throttle valve (38%) in case of throttling valve
cycle and in expander it occurs from gas cooler
(38%) and compressor (35%). Exergy analysis
of transcritical CO2 cycle is performed with
throttling valve and ejector by Ma Yi-Tai et al.
[14] and It is found that ejector reduces 70%
more exergy loses and increases COP up to 36%
in comparison to throttling valve. Goodarzi et al.
[15] Studied the modified transcritical CO2
refrigeration cycle. Modification was made by
extracting a line of saturated vapor flow from
separator and feeding to the intercooler and
concluded that COP of the modified cycle was
improved by 26.89% as comparison to original
cycle operating at a particular set of parameters.
And it is also repoted that as compare to original
cycle this modification averagely decreased the
exergy destruction rate by 18.6%.
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Study of transcritical CO2 cycle with
dedicated mechanical subcooling:J.W.Thornton et al. [16] compared an optimum
value of subcooling evaporator temperature of
an ideal dedicated mechanical subcooling cycle
and of a property dependent computer model.
Results exhibit that the optimum temperature of
subcooler evaporator greatly depends on the
extreme temperatures of the cycle, but less rely
on the subcooler heat exchanger parameters.
Rodrigo llopis et al [17] evaluate a transcritical
CO2 refrigeration system with dedicated
mechanical subcooling at two evaporating
temperatures (0 & 10°C) and three heat rejection
temperatures (24, 30 &40°C). And obtain a
increment of 55.7% in cooling capacity and
30.3% in COP for proposed system. Residential
building of 1.5 ton was taken and experiment
was conducted with and without using dedicated
subcooler at room temperature of 18 to 22°C by
Qureshi et al. [18] . Increase in efficiency was
found by 21% with the use of dedicated
subcooler. Fig. 2 explains the working of
dedicated mechanical subcooling cycle.
Subcooling is done in the vapor compression
refrigeration cycle to improve the coefficient of
performance of the system. Subcooling of the
refrigerant is done at the exit of condenser, to
allow the refrigerant to enter into the main
refrigeration cycle with lower quality so that it
can absorb more heat from the refrigerated space
in the evaporator. In dedicated mechanical
Subcooling vapor compression refrigeration
system, a small vapor compression refrigeration
cycle is employed to perform Subcooling. As
shown in figure 2, there are two cycles one is
main refrigeration cycle (situated below) and
other is dedicated subcooling cycle. Both the
cycles are coupled at the exit of condenser with
the help of subcooler. “In practice, the
components of the subcooling cycle are a
fraction of the size of the main cycle components
and perform through much smaller temperature
extremes. For this reason, the COP of the
subcooling cycle is appreciably higher than that
of the main refrigeration cycle. This high
subcooling cycle COP can result in an increase
in the overall cycle COP” [16].
Fig. 3, clearly shows that dedicated mechanical
subcooling cycle allows the refrigerant to enter
into the evaporator of main cycle with a lower
quality. Consequently, an increase in
refrigeration capacity per unit mass of
refrigerant circulated occurs.
Study of CO2 based transcritical cycle in
Indian context: Nilesh Purohit et al. [19] demonstrate that,
parallel compression is more effective with
transcritical CO2 cycle than inter-cooling in high
ambient temperatures like India. Maximum
improvement noticed in COP was about 25% for
parallel compression configuration. And for
parallel compression configuration the operating
gas cooler pressure was found lower. Figure 4
shows the basic transcritical carbon dioxide
refrigeration cycle and its P-h diagram as given
by Nilesh purohit et al. [19]. Refrigerant flows
from compressor to gas cooler where it gives off
its heat to another fluid and then through the
expansion device goes into the evaporator and
takes heat from the refrigerated space. As shown
in P-h diagram, at the exit of compressor it is
above critical point and heat rejection takes
place above critical point in the gas where no
saturation point exists. So at gas cooler exit the
gas cooler pressure is independent of the
refrigerant temperature. And evaporation takes
place below critical point.
Dasgupta et al. [20] reported that performance of
transcritical CO2booster system for supermarket
with expander is higher as compared to that
without expander, the mass flow rate and gas
cooler operating pressure is lower for cycle with
expander, gas cooler inlet temperature is higher
for cycle with expander beyond the operating
limit (12 MPa) in warm climates. Nilesh et al.
[21] analysed five CO2 booster refrigeration
cycles on the basis of energy and economic
aspects by taking temperatures from the four
cities of world (warm climates). New Delhi
found to be having higher annual energy
savings, the recovery time is longer and the total
money savings are lower owing to lower
electricity tariff. Gupta [22] demonstrate that
COP of a transcritical cycle can be improved by
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employing a recovery turbine. This study was
done for design and operating parameters based
on local environmental conditions for the best
possible performance (in Indian context).
Conclusion:
CO2 having GWP (=1) is a very promising
incumbent for refrigeration and air conditioning
industry. CO2 based systems have been giving
promising results in cold climates and now
researchers taking this CO2 based system and
studying it theoretically and experimentally for
the various refrigeration applications.
In Indian context, also it is being studied for the
supermarkets based on energetic performance
and more exergetic performance study should be
performed.
Figure contents:
Fig: l : layout and p-h diagram of CO2 cycle with
parallel compression economization[6]
Fig 2. : Schematic of a vapor compression cycle
with dedicated mechanical sub-cooling[18]
Fig 3. : Pressure-enthalpy diagram of a
refrigeration cycle with dedicated subcooling
[18].
Fig.4 : Basic transcritical CO2 refrigeration cycle
[19]
References:
[01] Brian T. Austin, K. Sumathy, 2011.
Transcritical Carbon Dioxide Heat Pump
Systems: A Review. Renewable and
Sustainable Energy Reviews 15; 4013–
4029.
[02] M.-H. Kim, J. Pettersen, And C. W. Bullard,
2004. Fundamental Process and System
Design Issues in CO2 Vapor Compression
Systems.
Progress in Energy and
Combustion Science, Vol. 30, Pp. 119-174.
[03] Lorentzen, G., 1990. Trans-Critical Vapour
Compression Cycle Device. Patent
WO/07683.
[04] D. K. Gupta And M. Dasgupta, 2010. Gas
Cooler Design Issues for Trans-Critical
Carbon Dioxide Refrigeration System in
Indian Context. In: Proceedings of the 3rd
International Conference on Advances in
Mechanical Engineering, SVNT, Surat,
India, Pp. 229-233.
[05] Aprea, C., Maiorino, A., 2008. An
experimental evaluation of the transcritical
CO2 refrigerator performances using an
internal heat exchanger. International
Journal of Refrigeration 31, 1006–1011.
[06] J. Sarkar, N. Agrawal, 2010. Performance
Optimization Of Transcritical CO2 Cycle with
Parallel
Compression
Economization.
International Journal of Thermal Sciences,
Vol. 49, Pp. 838-843.
[07] I. Bell, 2004. Performance Increase of
Carbon Dioxide Refrigeration Cycle with
the Addition of Parallel Compression
Economization. In: Proceedings of 6th IIR
Gustav Lorenzen Natural Working Fluids.
[08] Winkler, J., V. Aute, B. Yang, And R.
Radermacher, 2006. Potential Benefits of
Thermoelectric Elements used with AirCooled Heat Exchangers. In: Proceedings of
the International Refrigeration and Air
Conditioning Conference At Purdue,
Purdue University, West Lafayette, IN, July
17–20, Paper R091.
[09] Jahar
Sarkar,
2011.
Performance
Optimization
of
Transcritical
CO2
Refrigeration Cycle with Thermoelectric
Subcooler. International Journal of Energy
Research.
[10] Aklilu Tesfamichael Baheta, Suhaimi
Hassan, Allya Radzihan B Reduan, and
Abraham D. Woldeyohannes, 2015.
Performance Investigation of Transcritical
Carbon Dioxide Refrigeration Cycle. 12th
Global
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on
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Manufacturing. Procedia CIRP 26, 482 –
485.
[11] Alok Manas Dubey, Suresh Kumar,
Ghanshyam
Das
Agrawal,
2014.
Thermodynamic Analysis of a Transcritical
CO2/Propylene (R744–R1270) Cascade
System for Cooling and Heating
Applications. Energy Conversion and
Management 86; 774–783.
[12] K.S. Rawat, V.S. Bisht, A.K. Pratihar,
2015. Thermodynamic Analysis and
Optimization of CO2 Based Transcritical
Cycle. International Journal for Research in
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Applied
Science
and
Engineering
Technology, Volume 3 Issue III.
[13] Jun Lan Yang, Yi Tai Ma, Min Xia Li, Hai
Qing Guan, 2005. Exergy Analysis of
Transcritical Carbon Dioxide Refrigeration
Cycle with an Expander, Energy 30, 1162–
1175.
[14] Ma Yi-Tai, Wei Yun Xia, Li De-Ying, Sun
Fang-Tian, 2011. Exergy Analysis of
Transcritical Carbon Dioxide Refrigeration
Cycle with an Ejector. International
Conference on Computer Distributed
Control and Intelligent Environmental
Monitoring.
[15] Goodarzi M, Gheibi A., 2015. Performance
Analysis of a Modified Trans-Critical CO2
Refrigeration Cycle. Applied Thermal
Engineering; 75:1118–25.
[16] J.W.Thornton, S. A. Klein, J. W. Mitchell,
1992. Dedicated Mechanical Subcooling
Design Strategies for Supermarket
Applications. International Refrigeration
and Air Conditioning Conference.
[17] Rodrigo Llopis , Laura Nebot-Andrés,
Ramón Cabello, 2016. Experimental
Evaluation of a CO2 Transcritical
Refrigeration Plant with Dedicated
Mechanical Subcooling. International
Journal of Refrigeration 69,361–368.
Fig: l : layout and p-h diagram of CO2 cycle
with parallel compression economization[6]
[18] Bilal A. Qureshi, Muhammad Inam,
Mohamed A. Antar, Syed M. Zubair, 2013.
Experimental Energetic Analysis of a Vapor
Compression Refrigeration System with
Dedicated
Mechanical
Sub-Cooling.
Applied Energy 102, 1035–1041.
[19] Nilesh Purohit, Dileep Kumar Gupta, M.S.
Dasgupta, 2015. Thermodynamic Analysis
of Trans-Critical CO2 Refrigeration Cycle
in Indian Context. International Journal of
Scientific and Technical Advancements.
[20] Mani Sankar Dasgupta, Nilesh Purohit,
Dileep
Kumar
Gupta,
2016.
Thermodynamic Analysis of CO2 TransCritical Booster System for Supermarket
Refrigeration in Warm Climatic Conditions.
4th IIR Conference on Sustainability.
[21] Nilesh Purohit, Dileep Kumar Gupta, Mani
Sankar Dasgupta, 2017. Energetic and
Economic Analysis of Trans-Critical
CO2 Booster System for Refrigeration in
Warm Climatic Condition. International
Journal of Refrigeration; Volume 80, Pages
182-196.
[22] Dileep Kumar Gupta, 2017. Performance of
CO2 Transcritical Refrigeration System
with Work Recovery Turbine in Indian
Context. Energy Procedia 109, 102 – 112.
Fig 2. : Schematic of a vapor compression cycle
with dedicated mechanical sub-cooling[18]
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Fig 3. : Pressure-enthalpy diagram of a
refrigeration cycle with dedicated subcooling
[18].
Fig.4 : Basic transcritical CO2 refrigeration cycle
[19]
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Pump as Turbine: Review of Simple Modifications for Performance
Improvement
Doshi A. V.*; Bade M. H,
Mechanical Engineering Department, Sardar Vallabhbhai National Institute of Technology,
Ichchhanath, Surat-395007, Gujarat, India
Corresponding Author: avdoshi2001@gmail.com
Abstract
Energy to everybody is necessary for holistic development of society. Renewable energy sources are
gaining importance and their share in total energy is increasing as compared to fossil fuels in India.
For standalone energy generation, among various renewable energy conversion systems, pump as
turbine (PAT) are one of the potential device for micro hydro and energy recovery applications. Being
PATs are not designed for turbine operations, there is a scope for optimization of their performance
after selection for a field application. In this paper, literature related to performance enhancement
techniques is reviewed. However, main focus of this paper is to highlight the simple and cost-effective
modifications in PAT, which justifies the basic philosophy of low cost solution for micro hydro
applications.
Keywords: Pump as turbine, reverse mode operation of pump, simple modifications in PAT,
performance enhancement of PAT
1.
Introduction
The development of nation as whole is
considered in two major areas one is economic
and other is social. For both, energy is playing
a pivotal role. One of the important challenges
for government is to provide reliable, secure,
and affordable energy to everybody. There are
several energy sources mainly categorized as
non-renewable and renewable energy sources.
Due to climate change and limited resources of
non-renewable energy sources, renewable
energy sources are gaining importance and
their contribution in total energy generation is
increasing. Among various renewable energy
sources, micro-hydro power can be one of the
most important alternatives to isolated rural
communities due to the advantages of
electrification and the associated progress, as
well as to improve the quality of life. However,
due to higher cost of conventional turbines,
pump operation in reverse mode as turbine is
proved more cost effective. This is due to mass
manufacturing of pumps in different sizes and
designs, which can be matched with that of
available conditions of natural streams.
Pump as turbine (PAT) is one of the feasible
solutions to the energy problems in rural and
hilly areas. PAT is a pump operating in turbine
mode by changing the direction of flow and
hence direction of rotation of an impeller. PAT
is also finding its application in the area of
energy recovery systems for the existing
process industries. Use of PATs in large
hydropower plant as pump storage plant is very
well known and established method. All of
these applications of PAT are still attractive as
pumps are relatively simple machines with no
special design and are readily available in most
of the developing countries. In addition, their
installation commissioning and maintenance
are easy and cheap and from the economical
point of view, their payback period for small
hydropower application is approximately two
years.
Even though use of PAT as micro hydro or Pico
hydro application seems to be very attractive
due to all points which are discussed above, it
has always demanded for detail investigations
and careful research before they are used for
such purposes. The most important and
difficult area of PAT research is about their
selection to run them in turbine mode as per the
site requirements. As pumps are design for the
development of pressure head, so for in energy
recovery where they are used in turbine mode
operations, their performance may not be
optimal, hence researchers are also finding
another area of PAT research, which is to
modify the geometry of the selected PAT to
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improve the performance. Also, from the field
application point of view, further area of
research which are evolving now a days is to
get solution to the poor part load performance,
overcoming the problem of runaway condition,
overall system design and finding out the use of
PAT as energy recovery unit. In general, out of
various areas of PAT research, simple
modifications in PAT for performance
improvement is one of the important area,
where researchers have shown keen interest, as
it keeps cost benefits of PAT intact. In this
paper, review of simple modifications and
future scope of research is discussed.
Additionally, potential modifications are
highlighted.
Furthermore,
radical
modifications are summarized at the end.
2 Modification to improve PAT performance
To enhance the PAT performance, various
modifications
performed
are
mainly
categorized in two parts: simple and radical
modifications. The modifications carried out
on PATs by various researchers are
summarized Figure 1. Several researchers have
worked in the area of understating the internal
hydraulics of PATs by proposing the
theoretical model, which is useful to analyze
performance improvement
by simple
modifications.
2.1 Research on theoretical model for
simple modifications in PAT
Singh (2005) has made extensive work in this
area. In his work, a flow zone approach is
followed, in which PAT control volume is
divided into total seven flow zones with
detailed analysis of energy transfer and losses
in each of the zones. In the work, to evaluate
the PAT performance external and internal
parameters are identified. External parameters
are classified as input parameters like total
head (H), Discharge (Q) and output parameters
like hydraulic shaft power (Phyd.shaft) and
rotational speed (N). Internal parameters are
like whirl velocity (Vu) and flow velocity (vm)
of the fluid at the impeller inlet and outlet.
Also, to see any variation in the external
parameters an interlink between two
dependent hydraulic variable total head (H)
and hydraulic shaft power (Phyd.shaft) for PAT
control volume is established in terms of
hydraulic losses and net rotational momentum
(Euler’s head which is a function of internal
parameters). Further analytical model
proposed by Singh (Singh 2005) is
appropriately modified to account the
influence of non-flow zone (a region available
in the side room of PAT control volume) and
transition zone on PAT performance by Doshi
et al. (2017).
2.2 Simple Modifications in PAT
2.2.1 Inlet impeller rounding
Lueneburg and Nellson (1992) had performed
the modification on PAT of inlet blade
rounding, and rise in the efficiency of PAT
stated between 1 and 2.5 %. Singh (Singh
2005) based on flow zone approach and
internal hydraulics study, identified the area at
the inlet blade and shrouds of an impeller as
critical and feasible area for implementing the
modification in PATs. So, rounding operation
is performed at the inlet of the blades and
shrouds (see Figure 2) of an impeller to reduce
the flow separation and shock loss component.
In his study work, total 8 PATs of different
specific speeds (between 24.5 rpm and 94.4
rpm) were selected, for all the PATs,
performance improvement is analyzed at three
operating conditions viz. (i) part load (ii) BEP
and (iii) the overload. It is noted that overall
rise in the efficiency of PAT due to this
modification is in the range of 1.5 % to 2.5 %.
Suarda et al. (2006) has performed the
experiment on 18 rpm PAT by rounding of the
inlet ends of the impeller tips like a bullet-nose
shape to preclude excessive turbulence for
efficiency consideration, which is shown in the
Figure 3. The pump as turbine was operated at
the maximum head of 13 meter, and observes
change in the power and efficiency of the
pump as turbine after modification is slightly
higher than before the modification at BEP
point. Derakhshan et al. (2009) has modified
the optimized impeller of specific speed (Nq =
18.33 rpm) by rounding of leading edges and
hub/shroud inlet edges of PAT. Rounding of an
impeller has shown improvement in the values
of discharge, head, power and efficiency to 7.7
%, 9.5 %, 18.6 % and 2.5% respectively.
Doshi et al. (Doshi et al. 2017) had analyzed
impeller inlet blade rounding individually, i.e.
in three stages as impeller blade tip rounding,
inner shroud rounding (see Figure 4) and outer
shroud rounding with four selected PATs of
specific speed between 19 rpm to 54 rpm
covering low to medium range. From work, it
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is found that contribution in the performance
improvement of PAT from inlet blade
rounding is comparatively higher than shroud
rounding. Comparing similar modification
carried out by the various researchers, further,
it is noted that the rise in the efficiency due to
rounding of impeller at the inlet is maximum
up to 2.5 %. For further enhancement, it is
suggested to go for redesigning of blade
profile.
2.2.2 Insertion of inlet casing ring
Singh (Singh 2005) has discussed about
various turbulent and shock losses available in
the region between casing mouth and impeller
periphery of PAT. These losses are mainly due
to clearance (between casing mouth and tip of
the blade) and sharp edges of the fixed blades
at the inlet. In order to reduce such losses, an
external stationary ring is fixed at the casing
mouth to reduce the clearance between the
casing mouth and impeller periphery. Two
pumps (specific speeds 39.7 rpm and 79.1 rpm
respectively) were selected for performance
analysis by this modification; one (79.1 rpm)
for flat ring and other (39.7 rpm) for the
tapered ring insertion. The PAT with flat ring
has shown the positive change in efficiency of
maximum up to 1.4 %.
2.2.3 Suction eye enlargement
In most of centrifugal pumps, suction eye area
is contracting from the exit of impeller plane
towards the casing eye flange. However, in
PAT mode operation this area should be of
diffuser type with enlarging from exit of
impeller plane to the casing eye. This would
help in deceleration of the flow resulting in
pressure recovery, hence overall improvement
in the performance of PAT. Singh (Singh
2005) has taken two pumps (specific speeds
24.5rpm and 35.3 rpm respectively) for testing
performance
enhancement
of
this
modification. Mixed results were obtained
showing no improvement in efficiency for 24.5
rpm PAT and the reduction in efficiency for
35.3 rpm PAT at BEP. However, both the
PATs have shown rise in the efficiency at part
load condition.
2.2.4 Casing eye rib removal
In many pumps, manufacturers add the rib in
the casing eye region to break the pre-swirl at
the pump entry. In turbine mode operation this
rib will run axially along the casing eye length
and helps in reducing the swirl flow
component at the exit of PAT, on the other side
they will add to the friction losses due to
obstructions. Singh (Singh 2005) has shown
interesting results about the influence of casing
eye rib on the performance of PAT. For this
work, four pumps of different specific speeds
(36.4 rpm, 39.7rpm, 46.4 rpm and 79.1 rpm)
were selected. Out of these four test PATs only
one PAT having specific speed of 39.7 rpm has
given a positive performance with rise in
efficiency of about 1 % at BEP and up to 1.6
% in part load region.
2.3 Radical modifications in PAT
Few researchers also tried for performance
improvement of PATs by changing the overall
geometry of PAT, though it may leverage cost
benefit of simple modifications. Further,
researchers have tried to improve the
performance of PAT by adopting impeller with
splitter blades (Yang et al. 2012). Giosio et al.
(2015) had tried to improve the performance of
PAT at part load conditions by regulating the
flow rate with insertion of guide vanes, which
are generally used in conventional turbines.
Recently impeller with special type are design
for PAT operation and performance
improvement in PAT is analysed theoretically,
experimentally and numerically (Wang, Kong,
et al. 2017, Wang, Wang, et al. 2017).
4 Conclusions:
There are simple as well as radical
modification experimented by various
researchers for performance improvement of
PAT. In simple modifications, inlet blade
rounding is found as the most reliable and
effective modification giving performance
enhancement up to 2.5 %. Therefore, it is
strongly suggested. To get performance
improvement above 2.5 %, one may try for
radical changes in PAT. In this, one of the
modifications suggested is changing design of
impeller to match the flow condition to reduce
hydraulic losses.
References:
1. Derakhshan, S., Mohammadi, B., and
Nourbakhsh, A., 2009. Efficiency
Improvement of Centrifugal Reverse
Pumps. ASME Journal of Fluids
Engineering, 131 (2), 21103.
ISBN-978-81-932091-2-7
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2.
3.
4.
5.
6.
7.
8.
9.
Doshi, A., Channiwala, S., and Singh, P.,
2017. Inlet impeller rounding in pumps as
turbines: An experimental study to
investigate the relative effects of blade
and shroud rounding. Experimental
Thermal and Fluid Science, 82, 333–348.
Giosio, D.R., Henderson, A.D., Walker,
J.M., Brandner, P.A., Sargison, J.E., and
Gautam, P., 2015. Design and
performance evaluation of a pump-asturbine micro-hydro test facility with
incorporated inlet flow control.
Renewable Energy, 78, 1–6.
R.Lueneburg and R.M.Nellson, 1992.
Hydraulic power revcovery turbines, in:
V.S.Lobanoff et al. (eds.), Centrifugal
Pumps- Design and Application. Second
ed. Boston, US: Second Edition, Gulf
Professional Publishing.
Singh, P., 2005. Optimization of Internal
Hydraulics and of System Design for
PUMPS AS TURBINES with Field
Implementation and Evaluation. Ph.D
thesis University of Karlsruhe,Germany.
Suarda, M., Suarnadwipa, N., and
Adnyana, W.B., 2006. Experimental
Work on Modification of Impeller Tips
of a Centrifugal Pump as a Turbine. The
2nd Joint International Conference on
‘Sustainable Energy and Environment
(SEE 2006)’, 8 (November), 21–25.
Wang, T., Kong, F., Xia, B., Bai, Y., and
Wang, C., 2017. The method for
determining blade inlet angle of special
impeller using in turbine mode of
centrifugal pump as turbine. Renewable
Energy, 109, 518–528.
Wang, T., Wang, C., Kong, F., Gou, Q.,
and Yang, S., 2017. Theoretical,
experimental, and numerical study of
special impeller used in turbine mode of
centrifugal pump as turbine. Energy, 130,
473–485.
Yang, S.S., Kong, F.-Y., Fu, J.-H., and
Xue, L., 2012. Numerical Research on
Effects of Splitter Blades to the Influence
of Pump as Turbine. International
Journal of Rotating Machinery, 2012, 1–
9.
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PAT MODIFICATIONS
SIMPLE
RADICAL
INSERTION OF
GUIDE VANES
ROUNDING OF IMPELLER
AT INLET
REMOVAL OF CASING
EYE RIB
IMPELLER WITH
SPLITTER BLADES
SUCTION
EYE
ENLARGEMENT
•
INSERTION
CASING RING
IMPELLER WITH NEW
DESIGN
OF
Figure 1: Summary of modifications in PATs
Blade with rounding
Blade without rounding
(a) section of the impeller front view
Shroud without rounding
Back
shroud
Shroud with rounding
Front
shroud
(b) section of the impeller side view
Figure 2: Impeller Blade Rounding at inlet (Singh 2005)
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Figure 3: Inlet impeller rounding (Suarda et al. 2006)
Flow zone
Transition
flow zone
Flow zone
Non-flow
zone
Non-modified inner shrouds
Sharp eddies
Decreased
wakes and
changed
meridional
velocity profile
Inner shroud rounding
Figure 4: Hydraulic Effects due to Inner Shroud Rounding (Doshi et al. 2017)
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GROWTH, DESIGN ASPECTS AND APPLICATIONS OF
PHOTOVOLTAIC SYSTEMS
Jayesh Nehiwal 1Vineet Gehlot2,
1
Jodhpur Institute of Engineering &Technology
2MBM Engineering College, Jodhpur
Corresponding Author: jayeshnehiwal@gmail.com , vineet.gehlot@jietjodhpur.ac.in
ABSTRACT
Solar energy is resource which cannot be used or exhausted completely. The temperature is 15 million
0
C at the center of Sun core and at its surface it is approximately reaching 6000 0C. Being an effective
black body it has temperature of 57770C and so the sun effectively acts as a continuous fusion reactor,
many such fusion reactions takes place and hence there is production of solar energy, one of the important
reaction of hydrogen with four protons which combines to give helium nucleus. The reaction is here,
4(1H1)
2He4 + 26.7 Me V
This highly exothermic reaction gives us energy in order of MeV which is collected and converted in the
form of heat and further in electricity. This is really an important source of renewable energy and the
technologies characterizing is as either passively solar or actively solar. The use of photovoltaic systems
is in active solar power systems. In Passive solar system the techniques used are, that they orientate a
building towards the Sun in such a way that maximum sunlight falls on PV systems, selection of material
with favourable thermal, mass or light-dispersing applicative properties, and designing spaces so that
can naturally circulate air.
This paper is made to focus on photovoltaic solar cells, their designing aspects and their applications.
This ability of producing electricity directly with the help of the sunlight in the most abundant natural
resources, is the heart of this Photovoltaic research, and is explained as becoming one of the major
sources of power for our better “greener” future.
Keywords: Worldwide Scenario of Solar Energy, growth of solar PV system, designing of solar PV
system and applications of solar PV system.
INTRODUCTION
Contribution of Sun’s energy: It merely
contributes 94% of energy to Planet, it also
warms the surface of our earth and so the
atmosphere so that huge forms of life can live.
Without the solar energy, our earth will become
completely as a rock moving in infinity space
with temperature situations extremely low. We
humans, consume lot of energy in our day to day
life that within couple of years all of our existing
fossil fuels which are coal, gas, petroleum, etc
will get exhausted. Hence, solar energy has a
major responsibility to ensure itself as best
sustainable energy for our future generations and
also it can minimize the problems of carbon
emissions, global warming etc.
Photovoltaic collectors: These photovoltaic
collectors are the collectors which convert solar
radiation coming from sun directly into
electricity, without any kind of use of heat
engine in its configurations and with increase in
demand and requirement of public integration
and their purposes of using energy, the small
scale utilization of solar energy for desalination,
destination and detoxification of purposes with
water has also increased. With the help of these
solar collectors which are settled on the rooftops
of buildings and with the help of photovoltaic
cells of solar panels, the system is made to
synchronized with the active as well passive
energy systems.
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Photovoltaic effect: A basic theory of solar cell
is that, a wide area of semiconductor diode
which is having PN junction due to fabrication
of pentavalent element (Ph) or trivalent
element(B) with tetravalent element (Si,
commonly used for solar cells) to provide us
charge carriers, either minority or majority
depending
upon
holes
or
electrons
concentration. When light or sun radiation is
made to fall on this grouped semiconductor
being PN in nature, this generates the electron
hole pair giving a force or a kind of tension
between the contacts of provided n- side and pside of semiconductor and when we apply the
load, the current flows within this, making it as
completion of circuit as flow of charge is flow of
electric current and electric power is dissipated
in it.
Fig.1: Complete solar PV system
(source: www.solardirect.com)
GROWTH
Humans are capable enough to capture the solar
energy from sun directly, and with the help of
passive and active solar energy systems
intuitively in body. Ancient people in earlier
times made their minds so as used to build
their shelters and houses of stone or with clay
so that the heat absorbed in it can easily be
used in night time. Nowadays what builders
use to do is somewhat similar to methods for
passively capturing the Solar Energy, with
the help of photovoltaic cells.
For example, the construction of houses done
by them is planned with large double or triple
paned types of windows so that can get a
direction to capture the efficient sunlight and can
magnify the warmness of sun.
Active solar energy systems work on somehow
the same principles as the passive systems used
to do. But the Active solar systems also using the
fluid like water to absorb heat or to store heat.
Solar collectors which are oriented at the
rooftops pumps the heat to the whole system of
pipes and then further to the whole building, it is
passed on.
The best part of solar energy is, it is renewable
energy resource and present in abundant amount
in free in nature and the bad part of this is, that
the cost of system for the use of consumer is
expensive enough at initial stage of while
installations. The technology of solar PV was
known to us from the last decades and its
utilization was a task to finish, its minimal cost
of bills and efficiency in various other fields of
industries can develop the whole system of
integration in regards to this PV system. In India,
the geographical location is favorable as Tropic
of Cancer passes from middle of India hence for
solar energy implementation in India can be
done in worth, various companies are taking
interest to develop their scope and earn in this
field. Considering the socio-economic scenario,
India's present situation is fair with it, but many
other initiatives are planned and in a queue for
their implementations. And on considering the
historical scenario, the first commercial use of
new solar cells was done in a spacecraft in the
beginning of 1958. So from Small beginning to
a Terrestrial, solar cell industry is putting their
roots to grow rapidly to fight over Non
Renewable sources in the coming years. These
companies will increase the International
resolves, reduce the CO2 emissions and produce
effective energy for commercial purposes as
well as industrial purposes. Some statistical
figure shows the growth done in solar PV
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systems in last decade over the coal and wind
power plants in India. The report made by
Central Electricity Authority (CEA) of India for
the cost effectiveness for various Gol policy
instruments for 1MW solar PV installed in 201617 in rural and urban areas of India have
successful saving in energy and reduced the
average electrical cost for nation.
Table.1: Financial cost effectiveness for
various Gol policy instruments for 1MWsolar
PV installed in 2016-17(source: nitiaayog.com;
CEA report on 175 GW RE by 2022)
PV Module: It is having PV cells which are
wired in parallel so that it can increase the
current and in series so that to achieve a higher
voltage. Its basic function is to convert sunlight
into DC electricity. The module is layered with
protective covering of glass material.
PV Inverters: The batteries used in PV systems
can store direct current power which is used for
many applications. These inverter are for the
purpose to convert the low voltage DC into a
higher voltage AC and hence can be used for
other various applications.
PV Controllers: Controller word defines its
property that the battery life of PV system is in
regards with these controllers. If battery is
charged beyond its limitations then it will not
function and if such happens then the battery life
reduces.
PV controller system basically helpful in
opening the circuit between the PV battery and
PV array when voltage rises beyond set
.
PV Batteries: Batteries are for purpose of
storing charge and excess energy which is
created by PV system and to use in night when
there is no sunlight input is applied. These kinds
of batteries have ability to discharge and are able
to yield more current when applied to load
appliances.
Load: These are the electrical appliances which
will consume the electricity produced or stored
and are connected to the solar PV system such as
tube lights, refrigerator, fan etc.
Sizing a solar PV system:
1. Determination of power consumption
By the addition of each watt hour required for
all the appliances and get the total watt hours
required per day for all of the appliances(load).
DESIGNING A SOLAR PV SYSTEM
The major components of solar PV system are:
Multiply it by the total watt hours per day by a
factor of 1.3(for the total energy loss in our
system, it is assumption) to get the total watt
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hours per day which we will give to the PV
panels of our PV system.
35 % bigger than the total watt requirement of
the load.
4. Determination of sizing of battery
The type of battery which is recommended for
the solar PV system is ‘deep cycle battery’. In
this type of battery, it gets discharge slowly and
get charged comparatively faster. The battery is
taken large enough so that it can store the enough
amount of power to operate even in cloudy days.
Calculation done for the total watt per day is
taken and then divided by the factor of 0.85 (for
the loss of battery), 0.6 (for the depth of
discharge made by battery) and by the nominal
battery voltage which is 12 volts in our case.
Multiplying the above factor by the number of
days of autonomy which is usually from 2 to 3,
we consider 3 in our case.
Fig.2: Major components of PV system
(source: www.solardirect.com)
2. Determination of sizing of PV panel
PV modules of different size will produce
different amount of power. And to find the actual
size of PV module, the total peak watt (Wp) is to
be calculated. And Wp is dependent on the size
of PV panel as well as on the climatic conditions
of that particular location. For India, ‘panel
generation factor’ is 4.32.
The total watt per day required from the module
which is calculated, is then divided by the panel
generation factor (4.32) and hence get the total
watt peak rating which is required for PV panels
to operate the appliances.
To find the number of PV panels, we have the
total watt peak rating for PV panel and that is to
be divided by the rated output watt peak PV of
the given module. In our case it is 110 Wp.
3. Determination of sizing of inverter
The total watt of the load is not to be equal to the
input rating of the inverter. For our
considerations of the standalone system, the
inverter must be large enough so that it can
handle the amount of watt power used at a one
time. This is why we keep the inverter size 30-
5. Solar charge controller size
The solar charge controller is used for matching
the voltage of the PV array and the battery
identification is done so that the type of the solar
charge controller can also be expected that the
which one is correct for our use.
There are two types of controllers. One is series
charge controller and other is parallel charge
controller. The sizing which has to be done for
controller that completely depends on the total
PV input of current which is delivered to the
controller and that too depends on the
configuration of the panel (either it is in series or
in parallel).
According to standard practice in India, for
expecting the size of controller is done by the
taking the short circuit (Isc) of the PV array and
again a multiplication factor of 1.3 is multiplied
(to incorporate the loss caused by system).
6. Cost Estimation
The total cost of installation of PV system which
will reflect the ' pay back calculations ' of solar
power PV system.
Example of a household is taken
40-Watt two tube lights, used 4 hours per day
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60 -Watt fan, used 8 hours per day
One refrigerator, which runs 24 hours per day
with compressor or run 12 hours and off 12
hours.
The system is assumed to be having power of 12
volts dc, 110 Wp PV module, averagely the
sunlight available in a day is 8 to 10 hours per
day for equivalent in peak radiation. , factor of
1.3 is taken for incorporation of system loss and
losses due to dust and climatic changes ,
installation of PV system is done in India hence
panel generation factor is 4.32.
1.
Determination of power consumption
= (2 tube lights×40 watt × 4hours per day) + (60
watt × 8 hours per day) + (75 watt ×24×0.5 hours
per day)
=1700 watts hour per day
Required PV panel
=1700× 1.3
= 2210 watt hour per day
2.
Determination of sizing of PV panel
Total peak watt of PV panel as per its capacity=
2210/4.3
= 513.95 Wp
=550 Wp (on rounding off)
Number of PV panels required=550/110
Required number of modules =5 modules
This system if have at least 5 modules of 110 Wp
PV module then work properly.
3.
Determination of sizing of Inverter
Total watt power of appliances is =2×40+60+75
=215 watt
Due to safety purposes, considering size of
inverter to be 30-35%bigger
Hence inverter should be at least of 290 watt.
4.
Determination of sizing of battery
Appliance use of watt is =1700-watt hour per
day
Nominal voltage of the battery is =12 volts
Days of autonomy considered is =3days
Battery capacity will be
= (1700×3) ÷ (0.85×0.6×12)
The total ampere hours required for our
module is =833.33Ah
Hence the battery should be rated, 12 volts
900Ah of for 3 days autonomy.
5.
Determination of Solar charge
controller
The specifications of PV module at nominal
operating cell temperature (NOCT) are as
follows:
P=110 Wp
V =16.7 V
I=6.6A
Voc=21.3 V
(Voc is open circuit voltage)
Isc=7.5A
(Isc is short circuit current)
Rating of solar is given by
= (5 strings×7.5A) × 1.3
=48.75A
Hence the solar charge controller on making it
round off should be of at least 50 ampere.
6.
Cost estimation
Cost of arrays is =number of PV modules×
cost per module
=5×12000=Rs.60000
Cost of batteries is =number of batteries× cost
per battery
=1×15000=Rs.15000
Cost of inverter is =number of inverters× cost
per inverter
=1×10000
=Rs.10000
The
total
cost
of
system
is
60000+15000+10000=Rs 85000
(Additional cost of wiring may also be taken
consideration)
Payback calculations of solar PV system
In normal electricity bills Rs per unit or kWh is
6.5 is assumed and on monthly basis if average
rupees 1000 bill comes then per year Rs is 12000
required to pay bill which includes
some
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fix money which also has to be paid to power
grid companies. In 7.08 years the amount of Rs
85000 will be paid in normal electricity bills.
Benefits of solar PV system are
Solar PV panels can give us clean, green
energy. As there are no harmful emission of
gases from solar PV system.
Solar energy is free in nature and in abundant
amount and can be utilized at great extent.
PV panels give us the direct electricity
generated with the help of photoelectric
phenomenon.
Residential solar panels are of not so large
size and are easy to install
PV modules does not contain any moving
parts so they degrade very slowly and average
life of PV is boosted.
Limitations of solar PV system
Efficiency of solar panels are comparably low
from other electric power systems.
These solar panels are less reliable as many
persons are unaware of its benefits.
Installation of such PV system is quite costly.
When a continuous supply of electric power
is required, these solar panels are less
efficient in storing and giving energy.
APPLICATIONS OF SOLAR PV
SYSTEM
Thermoelectric refrigeration driven by solar.
Solar nanowires working with infrared
spectrum.
Microcomputer based control of a residential
photovoltaic power system
Imagine a future in which we are having solar
cells all around us, on windows, walls,
laptops. Such transparent photovoltaic cells
are already being developed by MIT
scientists, giving us advance solar
technologies.
CONCLUSION
The geographical location of India country can
stand for the tremendous scope in generation of
solar energy and its utilization so as to achieve
its maximum benefits and to provide nationwide
development in power and reducing costs of
power expenditure of India. With the
advancement and development of India,
implementations of several new plans will
establish solar grids. And in that, this renewable
energy is playing promising role not only in
India but in world. As the example coated of
household where solar PV panel system gives us
the idea of money saving when compared to
normal bills paid in power grid systems of
nonrenewable sources. We saw 85000 rupees
were required to install a solar panel and it will
become our own power generation system in
7.08 years whereas in other case family is
expected to pay bill for lifetime. If such huge
step of using solar energy is taken for world then
this will be the actual advancement in the field
of power systems in respect to generation,
transmission, and distribution.
Table 1: Financial cost effectiveness for
various Gol policy instruments for 1MWsolar
PV installed in 2016-17
Fig.1: Complete PV system
Fig.2: Major components of PV system
References
1. www.dummies.com
2. www.leonics.com
3. www.solardirect.com
4. www.solartown.com
5. www.wikipedia.com
6. M. Tripathi ,S.Yadav ,P.K.sadhu,S.K panda
-Renewable Energy
7. Chetan Singh Solanki-Renewable energy
technologies: a practical guide for beginners
8. Renewable Energy Systems: Advanced
Conversion Technologies and Applications
9. Real Goods Solar Living Sourcebook Your
Complete Guide to Living beyond the Grid
with Renewable Energy Technologies and
Sustainable Living (14th edition)
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10. Renewable energy technologies (Energyefficient house)
11. IEEE Press series on power grid engineering
by Digambar M. Tagare
12. Renewable energy technologies by Jean
Claude sabonnadriere
13. Solar Electric Power Generation Photovoltaic Energy Systems: Modeling of
Optical and Thermal Performance, Electrical
Yield, Energy Balance, Effect on Reduction
of Greenhouse Gas Emissions
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An Assessment of Wind Power Potential in Astana: A
Wind Power Plant Feasibility Study for Akmola
Region, Kazakhstan
Abduvakhit Junussov, Ainur Rakhymbay, Dhawal Shah2, Prashant K. Jamwal1, *
1
Department of Electrical and Electronic Engineering, and 2Deparment of Chemical Engineering,
Nazarbayev University, Astana, Kazakhstan
Corresponding Author: prashant.jamwal@nu.edu.kz
Abstract
Kazakhstan has a huge capacity of natural resources such as coal, oil, natural gas, uranium and great
renewable energy potential from solar, wind, hydro-power and biomass. However, the country is still
dependent upon fossil fuel for energy generation and 75% of total produced energy comes from coalfired power plants, which contributes to greenhouse gas emission and environmental problems [1]. The
development of power plants based on renewable energy is still on small scale since the upfront
investment is very high, while the internal rate of return is low.
While dynamic growth of Astana city has driven increased demand for energy supply, the existing
power plants in Central and Northern Kazakhstan have been already overused and are old. Therefore,
construction of new wind farms near Astana is an attractive solution, which can boost energy capacity of
region and gradually decrease CO2 emissions. The aim of this research is to assess the wind energy
potential of Akmola region along with the investigation on the development of energy and cost-efficient
wind power plant. In particular, the wind energy potential of this region with the specific site
characteristics has been analyzed. The design of wind farm is presented with appropriate layout and
power conditioning and utilization schemes. Simulations in MatLab/SIMULINK software are conducted
to reveal energy efficiency of the proposed wind farm. Finally, a financial analysis with environmental
impacts is discussed. In conclusion, the feasibleness analysis of wind farm construction is revealed as a
model procedure.
I. INTRODUCTION
Kazakhstan is the world’s ninth largest
country, which was founded after the dissolution
of the Soviet Union in 1991, with more than 2.7
million km2 land area and 17.4 million unevenly
spread population, where 47% of people living in
rural terrains [2]. The Republic of Kazakhstan is a
Central Asian country with continental land mass,
where a steppe grassland and pastureland
dominates in the North regions, desert and semidesert are characteristic to the Central regions, the
Southern part of country are covered by mountains
such as Tien Shan and Pamir, and Western regions
consists of catchments of Caspian and Aral Seas.
The total land for agricultural sector is 76.5 million
hectares, where the share of permanent pastures is
64%, while the 32% are arable lands for various
grain production [3]. This country is characterized
by the continental climate, where the
winters are cold with average temperature of 18.5°C in North regions and -1.8°C in South
regions in January, and summers are hot with
average temperature of 28.4°C in south and
19.4°C in north in July [4]. The continental type of
climate requires space heating in cold winter
periods and air conditioning in hot summer times,
which contributes to the increasing demand on
energy supply.
The largest contribution to the economy of
Kazakhstan comes from its natural resources such
as oil & gas and uranium, heavy industry such as
production of ferrous and non-ferrous metals and
agricultural segment. The mining and petroleum
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industries accounted for 42% of GDP in 2016 and
85% of country exports [5]. Generally, GDP of
Kazakhstan increased from 19.5 billion USD in
1991 to about 184.39 billion USD in 2017 with the
highest 236.6 billion USD rate in 2001. The annual
GDP rate has varied between -11.1% to 16.9%
since the foundation of Republic of Kazakhstan as
illustrated in Fig.1. The positive and significant
increase in GDP and per capita income has
resulted to the reduction of poverty in the country
from 47% in 2001 to approximately 5% in 2014.
However, the rapid economic growth has led to the
huge increase in energy demand, particularly in
winters. According to UNDP [6], the energy
consumption of Kazakhstan (in metric tons of oil
equivalent) has increased from 25.93 mtoe in 2000
to 92.3 mtoe in 2016, whereas the total power
production has raised from 46 TWh in 2000 to
about 94 TWh in 2016. Currently, the total
capacity of energy production is 20.1 GW where
only about 16 GW is usable and losses occur due
to poor maintenance, grid connection and
equipment aging [7]. The 78.44% of produced
power generated from thermal power plants,
7.86% comes from gas power stations and 7.86%
produced
from
hydropower
stations.
Unfortunately, the percentage of power generation
from renewable energy sources such as solar,
wind, biomass accounts for only 0.4% of total
energy production [8]. However, Kazakhstan has
a huge potential to generate electricity from the
renewable resources and government expects to
increase renewable energy production by 11% in
2020.
Figure 1. Kazakhstan’s GDP annual growth rate
[5]
Mainly, the total production of carbon dioxide
emissions in Kazakhstan is 235 MtCO2 in 2016
and 80% of it has resulted from the heat and
electricity generation plants [9]. Therefore, it is
crucial to increase the total share of energy
production from environmentally friendly and
efficient renewable energy sources in order to
achieve sustainable development and meet the
rising energy demand of the country. In addition,
Kazakhstan has signed the United Nations
Framework Convention on Climate Change and is
going to accept Kyoto Protocol, which states
improving energy quality for the environment
protection along with the sustainable economic
development [4].
Global Environmental Facility along with
United Nations Development Program (UNDP)
and government of Kazakhstan are investigating
on the discovery and development of wind power
implementation opportunities in Kazakhstan [10].
In fact, the attraction of investors from several
international companies and organizations to the
development of wind power generation is not only
due to the intention to decrease greenhouse gas
(GHG) emissions but also there is an excellent
chance to develop a profitable business in this
sector. According to GEF-UNDP wind resource
assessments, Kazakhstan has an exceptional
potential of wind resources. Particularly,
observations have revealed that almost a half of
Kazakhstan’s territory has a wind with 4-5 m/s
average speed at a height of 35m [11]. The
windiest sites of country are western regions near
the Caspian and Aral seas, central regions as well
as some south regions. It is estimated that the
annual production of power from wind turbines
could reach an 8-10 TWh. Hence, the construction
of wind farms will fulfill the expanding energy
shortages of the country as well as contribute to
less environmental pollution and impact on
population health.
This feasibility report investigates on the
assessment of wind farm implementation in
Astana city. In section II, a case study of Astana
city with detailed description of climatic
conditions is reported. Moreover, this section
includes the recent trends on energy production
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and energy demand of Astana city along with the
grid connection possibilities. Then, section III
proposes the layout of wind farm by describing
and selecting the most efficient wind turbines and
energy storage system. Section IV provides
economic analysis as well as assess possible
impacts caused by wind farm. At the end,
conclusion is given by suggesting whether it is
feasible to build a wind farm in Astana city or not.
II. SITE DESCRIPTION
The proposed location for wind farm
construction is situated within of 5 km of the edge
of the city with 51°08’ latitude and 71°28’
longitude. The area of selected site is about 8x10
km2 with the capacity for further wind farm
expansion. It is estimated that this land is capable
to produce up to 50 MW power.
Figure 2. The wind farm location in Astana city
The selected site lies in south part of Astana city
and 1.5 km apart from the southward residential
villages, as shown in Fig.2. The proposed area for
wind farm construction is in close proximity to
highway road line, which is beneficial for the
transportation of wind turbines to the site and fast
response to maintenance works. Moreover, the
city’s airport station is located 16 km apart from
the proposed site, and the flight path is in SW-NE
direction which will not disturb the function of
wind farm. In addition, the 110-kV high voltage
transmission line is adjacent to the wind farm
location and also there is a large power substation
within 1 km distance apart.
A. Climate features of Astana
As mentioned above, Astana is characterized
by sharp continental climate with extremely cold
winters and dry warm summers. The main feature
of continental climate is the significant changes of
air temperature, dry air and a small amount of
precipitation. The annual average temperature is 3.2°C and the average rainfall is 307 mm [5]. The
duration of cold time is on average 165-170 days
with a daily air temperature below 0°C. The
hottest period is in July with an average air
temperature of 20.9°C, whereas the coldest period
in January with an average air temperature of
15.2°C. Figure 3 illustrates the average air
temperature and the average rainfall in each month
of Astana.
Figure 3. The average air temperature and rainfall
of Astana [5]
B. Assessment of wind resource
The lack of protection from the penetration of
various air masses and relatively flat terrain results
to the favorable wind speed. The strong wind
speeds are typical for spring and summer periods.
The average monthly wind speed for Astana varies
between 4.0 m/sec to 6.3 m/sec [11]. The days
with strong winds up to 15 m/sec ranges from 10
to 50 days per year, while the windless days varies
between 50 to 70 annually. The direction of wind
in winter periods are to the south and in summer
periods to the north. The table 1 lists the average
monthly wind speeds of Astana.
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TABLE I. Average monthly wind speeds in
Astana [11]
Month
January
February
March
April
May
June
July
Wind
Speed
(m/sec)
5.2
5.1
5.4
5.2
5.0
4.4
4.1
Month
July
August
September
October
November
December
Annual
Wind
Speed
(m/sec)
4.1
4.0
4.1
5.1
5.3
5.1
5.8
In 2013 the UNDP [6] have conducted a
research toward the identification of wind power
potential in Astana city. The average wind speeds
at heights of 80 m, 51 m, 49 m and 22 m above the
ground level were monitored by using a tubular
tower with installed anemometers. In this research,
the data taken from these measurements have been
used for the feasibility analysis of wind farm in
Astana. Table 2 provides the results of
measurements conducted by UNDP.
TABLE II. Wind speed measurements at
height of 80 m, 51 m, 49 m and 22 m [6]
Measurements
Minimum
wind speed
(m/s)
Maximum
wind speed
(m/s)
Average wind
speed (m/s)
Level 1
(80 m)
Level 2
(51 m)
Level 3
(49 m)
Level 4
(22 m)
0.2
0.2
0.2
0.2
27.5
26.6
26.7
24.3
7.25
6.51
6.48
5.39
Astana is characterized by the repeatability
of high wind speeds and in cold periods of year the
wind is caused by western spur of the Asian
anticyclone [4]. Therefore, the direction of wind in
Astana predominantly is south-west, as
demonstrated in energy rose map (Fig. 4). As a
result, the majority of wind power initiated from
the south-west direction.
Figure 4. The wind direction and wind energy
distribution for Astana [4]
Moreover, the efficiency of generated wind
power is also influenced by the number of
atmospheric phenomena such as thunderstorms,
hails, blizzards, snowstorms and dust storms. The
storms are more frequent in summer and less
frequent in fall and spring. The annual average
number of days with thunderstorm is 23, the
average frequency of snow storms is about 38 days
per year. The occurrence of days with blizzard
varies between 20 to 50 on average per year,
whereas the days with dust storms meet 60 times
on average per year.
C. Energy production and consumption
Currently, the total power production from the
installed plants in Kazakhstan is 18.992 TW. The
percentage of electricity production from thermal
power plant is 87.7% and the rest 12.2% comes
from the hydroelectric power plant. About 70% of
energy is produced by burning a coal, 14.6%
energy generation from hydro resources, 10.6 %
from gas, 4.9% from oil, whereas only 0.4%
comes from the solar and wind resources [1]. The
huge percent of generated power is consumed by
the industry, which is about 68.7%. The domestic
energy consumption is 9.3%, the agricultural
sector consumes 1.2%, the transportation system
uses 5.6% from total production. The leaders of
energy production are Pavlodar and Karaganda
cities, which are located near the coal mines [14].
Figure 5 demonstrates the distribution of
electricity production level among all regions and
cities of Kazakhstan.
Figure 5. The total generation of electricity by
regions [14]
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The energy consumption differs among cities
of Kazakhstan. As Karaganda, Pavlodar, East
Kazakhstan cities have industrial factories, they
consume the most part of produced power.
Akmola region along with Astana city consumes
approximately 5 200 000 MWh energy.
There are two working combined heat and
power plants in Astana (CHP-1 and CHP-2),
which produce 22 MW and 360 MW of power
respectively. However, this produced amount of
energy is insufficient for the total demand of
fastest growing capital of Kazakhstan. Therefore,
the huge amount of electricity comes from
Pavlodar and Karaganda in order to fulfill the
energy requirements of Astana. The seasonal
energy consumption of Astana is shown in figure
7, where the most electricity is consumed during
winter periods [12].
Figure 6. The energy consumption by regions
[15]
Jan
Feb
March
Apr
May
June
July
Aug
Sept
Oct
Nov
Dec
Figure 7. The monthly power consumption of
Astana [12]
The electricity tariffs in Kazakhstan varies in
different cities depending on the transmission
distance, the percentage of occurred losses,
operation and maintenance cost of region. The
electricity price in Astana is 12.99 KZT/kWh for
the domestic consumption and 18.1 KZT/kWh for
other purposes [15].
The total length of high voltage electrical
lines is more than 5500 km for 500 kV, more than
20 200 km for 220 kV, 44 500 km for 110 kV, 62
000 km for 35 kV and approximately 204 000 km
for small 6-10 kV lines [13]. The power loss
during the transmission and distribution accounts
for 21.5 %, which is significantly. Particularly, the
Akmola region has 4300 km total length of high
voltage grid lines, 10 substations with the total
grid capacity of 7800 MVA.
III. DESIGN OF WIND FARM
Wind turbines
A wind turbine is a mechanical machine that
converts the kinetic energy of the wind into
mechanical by induced rotation of rotors blade
[16]. After that, generators convert produced
mechanical energy into desired electrical energy
for further consumption [16]. As the wind turbines
form the basis of wind farm, the proper selection
of them is a major concern.
Generally, there are two types of wind
turbines used for power production based on axis
of the turbine rotation: Horizontal Axis Wind
Turbine (HAWT) and Vertical Axis Wind Turbine
(VAWT) (see Fig. 8).
A.
1. Horizontal axis wind turbine
The horizontal axis wind turbine uses axis
parallel to the ground for a rotation. The structure
of horizontal axis turbine consists of a rotor,
blades, gearbox, generator located at the top of a
turbine tower, and the blades faced towards the
wind [16]. The shaft of a turbine starts rotating
when wind hits the blades, and then gearbox
attached to the end of the shaft turns a slow
rotation of blades into faster rotation to drive
generator [16]. Horizontal axis wind turbines are
more popular compared to vertical axis wind
turbines. Table III provides advantages and
disadvantages of HAWT.
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TABLE III. Advantages/Disadvantages of
HAWT [16]
Advantages
High efficiency
Installation is self-starting
High stability
Rotor blades can be pitched
Variable blade pitch
Disadvantages
Hazards for low height crafts
Difficult maintenance
Difficult transportation
Turbulence may cause fatigue
Bad aesthetic view
2. Vertical axis wind turbine
The vertical wind turbines use axis
perpendicular to the ground for rotation. The main
difference of this type is that this type of wind
turbine does not need to be faced towards the
wind, and its efficiency does not been affected by
change of the wind flow direction [16]. Moreover,
all components, such as gearbox, generator, and
transformer are placed near the ground. However,
due to low efficiency, VAWT is mostly applied in
small wind projects, while HAWT is mainly
implemented in large wind farms [16]. The
following table (Table IV) provides the
advantages and disadvantages of VAWT.
TABLE IV. Advantages/Disadvantages of
VAWT [16]
Advantages
Ease of maintenance
Better aerodynamics
Ease of transp. and install.
The efficiency is stable
No need of yaw device
Disadvantages
Only low heights
Low efficiency
Additional energy to start
rotation
Causes drag
Flat surface is required
So, from tables (Table III & IV), it can be seen that
HAWT is more suitable and preferable than
VAWT, for producing large amount of energy.
HAWT has higher efficiency, it is more stable, and
provides more warranty.
B. Choosing wind turbine type
It was stated above, that chosen location has
potential of producing about 50 MW of energy.
So, in order to achieve that, it is necessary to
choose the wind turbine which will fulfill
requirements of location, such as wind speed, air
density, and so on. Average wind speed is given in
Table I, it is important to choose the wind turbine,
which will be able to operate at low wind speed,
and which will have low cut-out speed to prevent
damage of turbine during the strong winds. After
some evaluations, Vestas V112 – 3.3 MW
horizontal axis wind turbine was chosen. Its
specifications are provided in Table V.
TABLE V. V112-3.3 MW description [17]
Operating Data
Rated power
Cut-in wind speed
Cut-out wind speed
3.3 MW
3 m/s
25 m/s
Table V shows that Vestas V112 is able to operate
at minimum wind speed 3 m/s, and if wind speed
will be higher than 25 m/s, it will stop operate.
Since one wind turbine is going to produce about
3.3 MW of energy, it is required to use 15 of them
to generate 50 MW of energy.
C. Wind farm layout
In order to get higher profitability from the
wind system, it is important to adequately design
wind farm layout. The careful and detailed
optimization of layout contributes to maximum
wind power capture. Here is the cost of energy
calculation equation:
∗
𝐶𝑜𝐸 =
+𝐶 &
(1)
Where, C1 is initial capital cost of wind farm,
FCR is fixed charge rate, Cr is replacement cost,
Cq&m is cost of maintenance and operation, AEP is
annual energy production.
From the equation 1, it can be seen, if the
annual energy production is increased, the total
cost of energy will be minimized.
“One of the main problems that cause the wind
power capture reduction is a phenomenon known
as a wake loss. When incoming wind encounters a
wind turbine, a linearly expanding wake occurs
behind the turbine [16]. Thus, the speed of free
stream wind is lowered. The phenomenon is
illustrated in Figure 8. The effect of wake loss on
several turbines is illustrated in Figure 9.
Therefore, it is apparent that the problem of design
optimization is mainly concerned with locating
wind turbines so that they are not affected by wake
loss.”
So, there are different computer software
which provide an algorithm for the layout design.
The algorithm uses different parameters, such as
number of turbines, planned area, height of the
turbine, average wind speed, temperature of the
air, grid connections, loads, and etc., to get
maximum annual energy production from the
wind farm.
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Figure 8. Wake loss [16]
Figure 10. Astana wind farm design
Figure 9. The effect of wake loss on wind
turbines [16]
By using Homer PRO software, the optimal wind
farm layout was found (see Fig. 10).
D. Grid connection
It is important to connect each wind generator
to the grid. Therefore, availability of the grid close
to the wind power plant site has to be considered
during selection of the location for power plant.
However, it is not enough to build a wind farm,
and just connect to the grid. The power plant has
to fully comply with grid requirements. As the
wind power is not stable during the year and
occurrences of power loss, it may bring a risk to
the reliability and stability of the entire power
system. Therefore, before implementation of wind
farm set of rules must be met and accomplished
such as frequency, reactive power, power factor
controls, voltage, and transient fault behaviors.
Moreover, people responsible for developing wind
farm should contact local Transmission System
Operators. In case of meeting all set of
requirements Electricity Grid Company (TSO)
will provide with necessary documents for Power
Purchase [18].
E. Matlab/Simulink Simulation
Figure 11. The Simulink model for wind turbine
Figure 12. Wind farm simulation results
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Here is the Simulink model for wind turbine
simulation (see Fig. 11). The simulation provides
the turbine output power, and wind speed.
calculated to be approximately 7 years (see Fig.
12).
For simulation, the wind speed was taken as
sinusoidal wave, with peak values equal to 30,
which is maximum possible wind speed in the
region.
So, Fig. 12 provides two graphs: one for wind
speed and another one for power output. It can be
seen that, when wind speed reaches to 3 m/s, wind
turbines start to produce energy, and when wind
speed reaches to 25 m/s (cut-out speed) then wind
turbines stop to generate energy. There is a point
on figure, when turbines start to generate constant
amount of energy. This wind speed is known as
rated output speed. At that speed turbines reach to
their maximum point, and operate in stable
condition.
IV. FINANCIAL ANALYSIS
Every project requires detailed financial
analysis, in order to estimate how much it will
cost, and how long it will take to pay-off it.
TABLE VI. Capital cost
Turbines + Installation & Transportation
Storage blocks
Maintenance
Inflation
Total cost
48 250 000$
1 173 000$
4 630 000$
12%
54 053 000$
TABLE VII. Operational revenue
Electricity cost
Average electricity growth cost
Required energy
Average growth of electricity cons
Corporate income tax
Cost for electricity
0.0565$
8%
180 000 MWh/year
4.5%
12%
10 170 000
Tables above (Table VI and VII) provide the
capital cost and operational revenue of the project,
respectively. The financial expenses for the first
year of the project include cost of land, storage
blocks, installation & maintenance of all 15
turbines, and transportation. Also, it was estimated
that due to inflation, each year capital cost of the
project will increase by 12%. It can be seen from
Table VII, that cost for electricity is not high, but
with increase of electricity consumption and
average electricity cost, pay-off period was
Figure 12. Total cost vs Total income
V. ENVIRONMENTAL IMPACTS
It is known that wind energy is one of the
cleanest and safest of the renewable energies.
However, it still has negative effect on the
environment. Of course, the effects are considered
to be minor, but they still have to be analyzed to
provide reasonable evaluation for the project. The
environmental impact can be divided into three
main categories:
1) Land pollution: According to [19], during the
construction and operation about 14164 m2 of land
per 1 MW is affected. Moreover, about 4047m2 of
land is always in use, and it can spoil the soil.
However, the spoiled soil still can be used for
pasture or agriculture [19].
2) Wildlife: It is known that the wildlife on
Kazakhstan is very wide and diverse. To be
precise, there are about 150 species of birds and 9
species of bats in the North part of KZ, which
periodically fly close to Astana [20]. As it is stated
in [21], it was scientifically proven that turbines
cause deaths and injuries to those species. The
damage can be explained by changes in landscape
and pressure drop near wind farms [21]. However,
those studies state that the casualties are low, if the
wind farm doesn’t stay on the route of migration
of birds. According to [22], there no migration
roads in Astana, so wild plant has to be safe for
wildlife.
3) Water and air pollution: Water is mainly used
only during construction process, so the water is
not polluted much. In case of the air, it also has
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effect only during construction period. Moreover,
during the operation of wind farm, there is heat
emission, which is also has to be taken into
account. However, this emission is much lower
compared to other sources of emission, such as
natural gas and coal [23].
VI. CONCLUSION
During this feasibility analysis, it was
necessary to analyze potential of wind power in
Astana, Kazakhstan. Site for construction was
chosen close to the edge of the city (5 km), and at
the same time close to high voltage transmission
lines. The detailed analysis of construction site
was conducted. All important factors, such as
wind speed, wind turbine type, annual energy
consumption of city, meteorological factors, were
considered during this research. It was proposed to
use 15 Vestas V112 horizontal axis wind turbine
with rated power 3.3MW, in order to produce 50
MW of energy. This type of turbines provides
efficient, reliable, and stable amount of energy
even during the low speed of wind. In order to get
maximum profitability from the research, layout
of the farm was also analyzed by using Homer Pro
software. Moreover, during this research
economical side of the project was discussed, and
it was found that it will take approximately 7 years
to get payback from the project. Finally,
environmental impact of the wind farm was
analyzed, and it was found that on chosen location,
farm will not cause side effects on environment.
So, for the future the wind power plant can
be improved to make it more echo and society
friendly. First of all, noise of the turbines could be
reduced by using more advanced prototypes of
blades. Also, to improve security of the farm,
internet of things can be applied, which will allow
to control the wind farm 24/7, even if being on
another side of the planet. Finally, with increase of
the annual energy consumption, it will be
necessary to expand the farm to fulfill energy
needs of the city.
REFERENCES
[1] M. Karatayev, M.L. Clarke, 2016, ‘A review
of current energy systems and green energy
potential in Kazakhstan,’ in Renewable and
Sustainable Energy Reviews, Vol. 55, pp.
491–504.
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at
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e/pii/S1364032115011570
[2] Agency of statistics of the Republic of
Kazakhstan. Demography and migration: an
outlook for 1991–2016.Available at
www.stat.gov.kz
[3] USDA. Kazakhstan: agriculture overview.
U.S. Department of Agriculture. Available
at: www.pecad.fas.usda.gov
[4] E. Danayev. (2008). Feasibility of Wind
Energy Development in Kazakhstan.
Available
at
http://www.esru.strath.ac.uk/Documents/M
Sc_2008/Danayev.pdf
[5] Kazakhstan GDP Annual Growth Rate.
[Online].
Available
at
http://www.tradingeconomics.com/kazakhs
tan/gdp-growth-annual
[6] Prospective of Wind Power Development in
Kazakhstan. (2006). UNDP/GEF and
Government of Kazakhstan wind power
project,
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at
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.pdf
[7] International Energy Statistics. [Online]
available
at
https://knoema.com/EIAIES2015Jun/intern
ational-energy-statistics-january2016?location=1001060-kazakhstan
[8] L. Parchomchik. (2017). Electricity
Generation in Kazakhstan: Current Trends
and Prospects. Available at http://eurasianresearch.org/en/research/comments/energy/
electricity-generation-kazakhstan-currenttrends-and-prospects
[9] Global Carbon Atlas. [Online]. Available at
http://www.globalcarbonatlas.org/en/CO2emissions
[10] Wind Atlas of Kazakhstan. (2013). UNDPGEF
project,
available
at
https://globalatlas.irena.org/UserFiles/cases
tudies/IRENA_Case_Kazakhstan.pdf
[11] J. Cochran. (2008). Kazakhstan’s Potential
for Wind and Concentrated Solar Power.
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[12]
[13]
[14]
[15]
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[18]
[19]
[20]
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at
https://www.kimep.kz/css/files/2014/07/Co
chran_Wind_and_Concentrated_Solar.pdf
Atakhanova Z., Howie P. (2007)
ELECTRICITY
DEMAND
IN
KAZAKHSTAN. Energy Policy, 35, p.
3729-3743.
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at
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e/pii/S030142150700016X
KEGOC. (2016). Annual Report 2015.
Astana.
Available
at
http://www.kegoc.kz/en/shareholders-andinvestors/information-disclosure/generalmeetings/2015
KOREM. (2016). Report on the results of
monitoring electric energy market and
centralized bidding for 9 months of 2016.
Astana.
Electricity tariffs in Astana. (2017).
Available
at
http://www.astanaenergosbyt.kz/tarif
Patnaik, I. (2009). Wind as a renewable
source of energy. Retrieved March 20, 2015
from:
http://ethesis.nitrkl.ac.in/1420/1/thesis_of_i
shan_ patnaik(10502038).pdf
Vestas Wind Systems A/S. (2014). V1123.3 MW™ at a Glance. Retrieved February
15,
2015
from
http://www.vestas.com/en/products
_and_services/turbines/v1123_3_mw#!at-aglance
Teodorescu, R., Liserre, M. and Rodriguez,
P. (2011). Grid converters for Photovoltaic
and Wind Power Systems. John Wiley &
Sons, Ltd: United Kingdom.
Denholm, P., Hand, M., Jackson, M., and
Ong, S. (2009). Land-use requirements of
modern wind power plants in the United
States. Retrieved March 15, 2015 from
http://www.nrel.gov/docs/fy09osti/45834.p
df
Kuznetsov, B. (1975). Key to vertebrates
fauna in USSR. Prosveshenie. Retrieved
March
15,
2015
from
http://zoomet.ru/kyz/kyznesov_
2_2.htmlhttp://zoomet.ru/kyz/kyznesov_2_
2.html
[21] National Wind Coordinating Committee
(NWCC). (2010). Wind turbine interactions
with birds, bats, and their habitats: A
summary of research results and priority
questions. Retrieved March 15, 2015 from
https://nationalwind.org/research/publicatio
ns/birds-and-bats-fact-sheet/
[22] Advantour (2015). Unique natural scenery
of Northern Kazakhstan. Retrieved March 5,
2015 from http://www.advantour.com
/rus/kazakhstan/northern.htm
[23] Edenhofer, O., Madruga, R. and Sokona. Y.
(2012). Renewable Energy Sources and
Climate Change Mitigation. Retrieved
March
9,
2015
from
http://srren.ipccwg3.de/report/IPCC_SRRE
N_Full_Report.pdf
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Energy efficiency of PV panels under real outdoor
conditions – An experimental assessment in Kazakhstan
Ali Mubarakov1, Sanzhar Sultan1, Nurzhan Arkabayev1, Dhawal Shah2, Prashant K. Jamwal1,*
1
Department of Electrical and Electronic Engineering, and 2Deparment of Chemical Engineering,
Nazarbayev University, Astana, Kazakhstan.*prashant.jamwal@nu.edu.kz
Abstract
This paper provides an analysis of temperature effect on the performance of solar panels. Specifically,
wider temperature range which prevails in Astana, Kazakhstan is considered. Previous work related
with PV cell performance under extreme weather conditions had been carried out on a single PV panel
in different temperature ranges. However, in the present research the performance, conversion
efficiency and maintenance of different PV panels in Astana weather conditions are investigated.
MATLAB simulation using existing PV panel models have been performed with various climate
conditions and compared with the real data which is collected from Alfa-solar PV panels situated in
techno-park of Nazarbayev University, Astana. Homer software® is used to assess financial aspects of
PV system. The results from this research can help significantly in the evaluation of solar panels
application in extreme conditions.
INTRODUCTION
Direct utilization of solar energy as power source
have already experiencing massive worldwide
commissioning and installation of PV plants,
from 5W panels to supply rural lighting to large
systems for modern towns. Massive adoption of
new technologies, on the other hand, leads to
additional issues formerly unaddressed and
invisible. The current research in this area
remains focused on mono and poly Si cells,
because most of the PV systems nowadays are
based on this technology. Further, PV panels
works with higher efficiencies in direct sun
irradiation with less obstacles and if cells are
maintained at low temperatures. The location of
installation (longitude, altitude and latitude)
foremost defines the solar power accessible for a
fixed PV panel. The terrain, exposure, and
common
environmental
conditions
also
sufficiently impact the performance of the PV
panels. Particularly, the dust has the strong
obvious effect on PV panel efficiency [1]. The
size of the PV system and the prevalent wind
circulations would also define whether wind
alleviates or aggravates dust settlement, in
addition to heat exchange process.
I.
II.
LITERATURE REVIEW
Influence of dust
The influence of dust on the performance of
Si PV panel is studied in [2]. Depending of
amount, density and composition of dust, it
can have different impact on the output panel.
In particular, small amount of dust could
actually benefit overall performance due to
fact that it adsorbs part of unwanted
wavelength of solar irradiation. This in turn
results lower temperature of solar cells, and
thus higher efficiency of the system (Fig. 1).
In addition, this small particle of dust only
catches undesirable light wavelength, while
other ranges can participate in electricity
generation. In fact, Si based panels generates
electricity only with visible spectrum,
whereas the rest converted to heat the system
which can be stored by dust particles on the
surface. As a result, utilizing this feature
could also decrease the frequency of cleaning
process of PV panels as well, through analysis
of data from monitoring system. On the
contrary, larger amount of dust on the top
glass of the PV panel does not allow the light
to reach the cell, resulting lower efficiency of
the system.
A.
B.
Temperature effect
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In [3] mathematical model of mono-crystalline Si
PV cell is devised using classical single diode
model. There solar cell is considered as a current
source which produces current proportional to
the irradiation capacity. In the suggested model,
series Rs and shunt Rsh are responsible for
ohmic losses in panel.
Fig. 1. Temperature difference between dusty
and clean PV panels
Further this model is implemented in LabVIEW,
which allows to study major PV panel
parameters under different values of solar
irradiance and cell temperature. In particular,
designed simulation project calculates and plots
power-voltage, current voltage curves, as well as
system efficiency, fill factors (FF), open-circuit
voltage, etc. The simulations are carried out
under constant irradiance of 1 kW/m2 and
varying temperatures. In terms of results, well
consistency with datasheet approves model
accuracy. In addition, proposed design is
flexible, and can be utilized for PV cells from
different manufacturers.
The effects of solar irradiance and temperature
on the performance of different types Si solar
panels are discussed in [4]. Particularly, solar
intensity had been changed from 0.2 to
1.0 Sun, and have significant impact on current
behavior. All of the following parameters
including short circuit, photo current and
maximum current increase linearly as solar
irradiance goes higher. Therefore, the
significance of concentrating system is noted
which allows increase the output capacity.
However, as it is revealed, without cooling
option output power of the system also declines.
Owing t o concentrated light a n d more heat,
temperature of PV cells goes up. This decreases
open circuit voltage and maximum voltage.
The maximum output power falls by 14 to 25
per cent for poly and mono crystalline Si,
under module temperature range of 10◦C500◦C.
A solar panel is a device, which consists of
PV cells that are connected in series and
parallel. Partial shading is a condition, when
part of PV cells is covered by clouds or by the
shadows of nearest buildings. Under this
condition, received solar irradiance of
different PV cells varies. For each value of
solar irradiance, a PV cell is able to produce
current, that
it less than its short circuit.
Hence, if two parallel connected PV cells
obtain different irradiances, reverse bias
operation of several PV cells occurs. This
condition brings hot spot formation in PV
panel. Utilization of bypass diodes is one of
the solutions of this problem. Operation of
bypass diodes leads to appearance of multiple
peaks in power curve. Therefore, partial
shading condition leads to transformation of
electrical characteristics of PV panel,
comparing it to same of PV panels under
normal conditions [5].
C. Effect of air velocity and humidity
The work of Mekhlief and Saidur has also
considered such factors as air velocity and
humidity that has a minor effect on PV
performance [6]. The originality of their paper
is in study of their effects in parallel and how
they interact with each other. The air velocity
was related to the temperature of the cells. As
wind velocity increases cell temperature will
decrease, as a result PV cell efficiency will
increase. In addition, it was mentioned that
performance is heavily dependent on cell
type. Effect of humidity was considered in
two different ways; first one affected
irradiance level, while second one is
ingression of humidity to cell enclosure. Also,
two module failure types and their impact on
short circuit current and open circuit voltage
were reported [6].
The effect of varying climates was described
by Hermann and Bogdanski. Climatic impacts
were considered in terms of three parameters,
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as irradiation, ambient temperature and relative
humidity. The test sites were Germany (moderate
climate), Indonesia(tropical climate), German
Alps (high mountain cli- mate) and Neged Desert
of Israel (arid climate). The main objective of
paper was to develop accelerated laboratory
testing, to predict cell performance after 25 years
of performance. The results from testing show
that same cells have different degradation types
[7].
PV field
performance under different
environmental conditions and atmospheric
parameters was considered by Micheli, Muller
and Kurtz. The main focus was made on soiling
losses with complex mechanisms and
interactions. PV cells were located in different
locations to identify the most influencing factors
that result in accumulation of dust. The
calculations included such parameters as airquality indexes, amount of rainfall, climate zone
and recurrence [8].
III.
METHODOLOGY
A. Data collection
In order to make an assessment of PV panels
under real outdoor conditions in Astana, data
from real existing PV panels have been collected
and processed. Two PV plants that have been
observed are located in Technopark at the
Nazarbayev University, Astana. Their capacities
are 10 and 15 kw. Current in phases A, B, and C
of these 10 and 15 kW solar plants have been
recorded within the month of January and March.
Recording was conducted for every 30 seconds
from 9 AM to 7 PM, due to the fact, that current
during night is close to zero. After that, from all
the numbers collected, average value for each
day was received by using MS Excel. By using
received data, graphs that are provided were
plotted.
Fig. 2. Change of current in 10 kW and 15 kW
PV plants within January.
Fig. 2 illustrates the change of current of 10
kW and 15
kW plants within a January.
Current that was generated by 15 kW plant is
bigger, than current that was generated by
10 kW plant. 10 kW plant produces relatively
stable current, with average value around 4 A,
with only fall on the 25th and 26th of January.
At the same time, current of 15 kW plant
is
fluctuating during observed period, from less
than 2 A to more than 11 A, which may be
caused by several conditions, such as dust on
the PV panel. On the 25th and 26th of March
both PV plants showed poor performance,
which was dictated by extremely cloudy
weather in Astana.
Fig. 3. Change of current in 10 kW and 15
kW PV plants within March.
As it is clear from Fig. 3, currents in phases
A, B, and C are almost equal, and cannot be
distinguished. Obviously, 15 kW solar power
plants have higher current values, than 10 kW
solar power plants.
A 15 kW plant has values of current nearly
10 A during observed period, whereas
average value of 10 kW plant is around 7 A.
But, on the 2nd, 4th, 8th, and from 22nd to
31st of March, values are lower than average.
This may be explained by cloudy weather,
with big amount of snow that was present
during these days. Table I and Table II
illustrate daytime and evening temperatures
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during January and March. Also, drop in
generation of current can be caused by dust,
which gathered on the PV panel.
TABLE I
TEMPERATURE IN JANUARY [9]
Date
11.01.2017
12.01.2017
13.01.2017
14.01.2017
15.01.2017
16.01.2017
17.01.2017
18.01.2017
19.01.2017
20.01.2017
21.01.2017
22.01.2017
23.01.2017
24.01.2017
25.01.2017
26.01.2017
27.01.2017
28.01.2017
29.01.2017
30.01.2017
31.01.2017
Daytime T(◦C)
-12
-12
-18
-14
-13
-13
-12
-7
-8
-13
-11
-11
-11
-14
-6
-4
-5
-6
-10
-7
-8
Evening T(◦C)
-16
-17
-18
-16
-17
-19
-16
-12
-10
-14
-13
-17
-14
-14
-6
-6
-6
-12
-12
-13
-8
Description
Cloudy, snow
Cloudy, snow
Cloudy
Cloudy
Cloudy, snow
Cloudy, snow
Cloudy, snow
Partly cloudy
Cloudy, snow
Cloudy, snow
Cloudy
Cloudy, snow
Fig. 4. Change of temperature within January
Cloudy, snow
TABLE II
TEMPERATURE IN MARCH [9]
01.03.2017
02.03.2017
03.03.2017
04.03.2017
05.03.2017
06.03.2017
07.03.2017
Daytime T(◦C)
-9
-6
-3
-5
-4
+1
-6
Evening T(◦C)
-9
-6
-5
-7
-6
-6
-11
08.03.2017
09.03.2017
10.03.2017
11.03.2017
12.03.2017
13.03.2017
14.03.2017
15.03.2017
16.03.2017
17.03.2017
18.03.2017
19.03.2017
20.03.2017
21.03.2017
22.03.2017
23.03.2017
24.03.2017
25.03.2017
26.03.2017
27.03.2017
28.03.2017
29.03.2017
30.03.2017
31.03.2017
-6
-11
-9
-5
-5
-7
-6
-4
-5
-5
-4
-3
-1
-1
+2
+4
+2
0
+1
+3
+3
+2
0
+4
-7
-12
-12
-10
-10
-10
-19
-6
-11
-11
-10
-8
-7
-8
-5
+1
+1
-2
0
+2
+3
+1
-2
+5
Date
Description
Partly cloudy
Cloudy, snow
Cloudy, snow
Cloudy
Cloudy
Cloudy, snow
Cloudy
Cloudy
Fig. 5. Change of temperature within March.
Cloudy
Fig. 4 shows the weather conditions in Astana
in January. It was plotted by using data
obtained from weather diary [9]. Temperature
grows from -16 to -8, with slight difference
between daytime and evening temperatures.
More than a half of the month was cloudy and
snowy.
Cloudy
Cloudy
Cloudy, snow
Cloudy, snow
Cloudy, rain
Cloudy
Cloudy
Cloudy
Partly cloudy
According to Fig. 5, temperature in March
grows from -10 to +5 at the end of the month.
To sum up, primary weather factors that affect
generation of current are cloudiness of the
sky, and snowfall that covers PV panel.
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Simulation
As it said earlier, the power generated by PV
modules depends on various conditions. A set of
these conditions is called Standard Test
Conditions (STC) and specified on Table III:
TABLE III
STANDARD TEST CONDITIONS
B.
Parameter
Irradiance at normal
incidence
Cell temperature
Solar Spectrum
Symbol
G
T
AM
Value Unit
1000 W/m2
◦C
-
25
1.5
The STC is related to the IEC 60904 standards,
for PV modules following parameters are defined
with 10% tolerance: open-circuit voltage Voc,
short-circuit current Isc and maximum-point
power (Pmpp). In reality, standard conditions
occur seldom.
Common I-V curves and P-V curves are tested
for different cell temperatures and irradiances by
Simulink. Simulation settings are taken from
Pyramid 60-240Wp solar cells’ specifications
which are installed on PV panels of Technopark.
Table IV displays the solar cells’ characteristics.
TABLE IV
SPECIFICATIONS OF PYRAMID 60240WP PV MODULE ALFASOLAR
Specification
Short circuit current
Open circuit voltage
Maximum power current
Maximum power voltage
Maximum system voltage
(IEC)
Maximum power rating
Symbol
Isc
Voc
Impp
Vmpp
-
Value
8.84A
37.37V
8.11A
30.19V
1000V
Wp
240W
Fig. 6. A structure of PV module model [10].
The Voltage input PV model is taken from
[10], utilizing two inputs and two outputs in
addition to PV panel specification settlement
for initialization of module.
Using this
model, various cell characteristics are
generated under changing irradiance with
constant temperature and vice versa. The
general form of the model is shown in Fig.
6.
The module’s I-V curves at constant
temperature and with different irradiances are
depicted in Fig. 7. The solar irradiance was
changed from 200W/m2 to 1000W/m2
whereas temperature remained at 25 ◦C.
Clearly, when the irradiance increases the IV curve moved higher. Short circuit current
± open
is also affected greatly. In contrast,
circuit voltage experienced small changes in
value throughout the irradiance variation. In
terms of P-V curves, similar relation to
current is observed for Maximum Power of
PV cell under similar simulation (Fig. 8).
Similarly, Fig. 9 displays I-V curves for
different temperatures and 400W/m2
constant irradiance. In particular, temperature
are chosen 0◦C and +40◦C. Also the P-V
curves for these module temperatures at
constant I=400W/m2 are illustrated in Fig.
12. According to Fig. 9 and 12, it is obvious
that at lower temperature, the values of
maximum power and open circuit voltage get
higher. In sharp contrast to that, short circuit
current decreased slightly as the cell
temperature declined.
Evaluation with Homer
The economy is important function in
designing solar power systems. The main
elements in cost system are solar panels,
inverters and construction expenditures. The
economic aspects of PV system were
analyzed by HOMER Pro software. Net
present value (NPV), payback period and
leveled cost of energy were assessed in this
section.
The electric load in this research was set to
residential type with peak month of July.
Numerical value of load was found by
C.
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considering each appliance in average house as
shown in Table V. Daily and seasonal profiles
for Astana are illustrated in Fig. 11. Electrical
components for each solar power plant must be
designed accurately.
Fig. 10. P-V curves for various irradiances at
T=25◦C.
Fig. 7. I-V curves for various irradiances at
T=25◦C.
Fig. 11. Load profiles
Fig. 8. P-V curves for various irradiances at
T=25◦C.
§
Fig. 9. I-V curves for various temperature and
constant I=400W/m2.
For safety reasons inverter size must be 2530% larger than total Watts of domestic
appliances. In this case inverter size should be
not less than 3.5kW. Therefore, for simulation
purposes Leonics S-219Cp 5kW inverter with
48Vdc nominal voltage was chosen. Battery
size (Ah) was calculated by the formula
below:
7182W ∗ Autonomy
=
Size (Ah) =
880Ah
0.85 ∗ 0.6 ∗ Voltage
Autonomy value was set to 3 days and voltage
to 48Vdc, which must have identical value
with inverter nominal voltage. For simulation
CELLCUBE R FB 20-40 with nominal
capacity of 833Ah and with 48Vdc nominal
voltage was selected.
The total cost of the system is illustrated in
the Table VI. The PV panels cost include the
installation, connections and panels cost itself.
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Results are discussed in Table VII.
TABLE V
POWER CONSUMPTION OF ONE HOUSE
Device
Power (W)
Lamp
Fan
Refrigerato
r
Oven
TV
Others
Total
18
60
180
Hours used per
day
4
2
24
Energy
(Wh)
72
120
4320
1
5
6
2400
150
120
7182
2400
30
20
2708
DISCUSSION
In data analysis section graphs that were
obtained, show that although temperature
influences the power generation in PV panels,
its effect is cannot be compared to the effect
of
IV.
TABLE VI
TOTAL COST OF THE SYSTEM
Unit
Size
Capital cost
O&M cost
PV panels
2.5kW
5000$
4.09$/year
Inverters
3.5kW
600$
0
Batteries
833Ah
500$
20$/year
cloudiness of the sky and snowfall. For
instance, generation of current by 15 kW PV
plant in January, fall from 11 A to less than 2
A, due to cloudy weather. Also, average
generation of current in March is bigger than
in January. This is the result of larger number
of clear days.
Fig. 12 illustrates I-V curves of Pyramid 60P
for different irradiance at temperature 25◦C.
Simulated curves, particularly in Fig. 7,
revealed that they are consistent with
characteristics of Pyramid 60P from
datasheet.
In economical part payback period was
calculated by considering net present cost and
savings of the entire project. Savings are total
amount of money saved, because of
autonomous energy generation, being
independent from electrical grids of Astana
with
tariff
of
0.067USD/kWh[11].
Economical result in terms of payback period
is not attractive for investors or home owners.
The reasons are aging of equipment and
maintenance in Astana snowy conditions.
TABLE VII
ECONOMIC RESULTS
System
PV
Fig. 12. I-V curves of Pyramid 60P solar module
(reference: Alfasolar datasheet).
Temperature data obtained from Technopark was
used in simulations for one home condition.
Payback period and NPV were later obtained.
Savings($
)
2977
NPV($)
43372
Payback
CoE
13.1 years
0.399
V. CONCLUSION
Mathematical model of PV panel was studied
and model of voltage input PV module was
devised. According to the results, temperature
decrease had a positive impact on output
power of the system. It was shown that
irradiance at cold temperatures resulted in an
increase in output power. General I-V and PV curves were obtained using SIMULINK.
Data was collected from Nazarbayev
University Technopark. The data was
processed and graphs of current change were
developed for March and January. Economic
aspects were simulated in HOMER software.
In terms of future works, other environmental
factors as wind speed and snowfalls shall be
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studied. The developed model can be improved
in order to observe effect of extreme
environmental conditions to accurately assess the
performance of PV panels in central Kazakhstan.
In addition, data from Technopark for full year
can be further analyzed to observe system
Behaviour under other extreme weather
conditions.
REFERENCES
1.
Rao, R. Pillai, M. Mani, and P.
Ramamurthy, “Influence of dust de- position on
photovoltaic panel performance,” Energy
Procedia, vol. 54, pp. 690–700, 2014.
2.
K. K. Khanum, A. Rao, N. Balaji, M.
Mani, and P. C. Ramamurthy, “Performance
evaluation for pv systems to synergistic
influences of dust, wind and panel temperatures:
Spectral insight,” in Photovoltaic Specialists
Conference (PVSC), 2016 IEEE 43rd. IEEE,
2016, pp. 1715–1718.
3.
Nanjannavar, P. Gandhi, and N. Patel,
“Labview based pv cell characterization and
mppt under varying temperature and irradiance
conditions,” in Engineering (NUiCONE), 2013
Nirma University Inter- national Conference on.
IEEE, 2013, pp. 1–6.
4.
El-Shaer, M. Tadros, and M. Khalifa,
“Effect of light intensity and temperature on
crystalline silicon solar modules parameters,”
Interna- tional Journal of Emerging Technology
and Advanced Engineering, vol. 4, no. 8, pp.
311–326, 2014.
5.
M. Hasan and S. Parida, “Temperature
dependency of partial shading effect and
corresponding electrical characterization of pv
panel,” in Power & Energy Society General
Meeting, 2015 IEEE. IEEE, 2015, pp. 1–3.
6.
S. Mekhilef, R. Saidur, and M.
Kamalisarvestani, “Effect of dust, humidity and
air velocity on efficiency of photovoltaic cells,”
Renewable and Sustainable Energy Reviews,
vol. 16, no. 5, pp. 2920–2925, 2012.
7.
W. Herrmann and N. Bogdanski, “Outdoor
weathering of pv mod- ules—effects of various
climates and comparison with accelerated
laboratory testing,” in Photovoltaic Specialists
Conference (PVSC), 2011 37th IEEE. IEEE,
2011, pp. 002 305–002 311.
8.
L. Micheli, M. Muller, and S. Kurtz,
“Determining the effects of environment and
atmospheric parameters on pv field
performance,” in Photovoltaic Specialists
Conference (PVSC), 2016 IEEE 43rd. IEEE,
2016, pp. 1724–1729.
9.
https://www.gismeteo.kz/.
10. “Pv module. simulink models,” in
ECEN 2060. Colorado University, 2008, pp.
1–11.
11. http://www.astanaenergosbyt.kz/tarif/.
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Design and Performance Evaluation of Improved Biogas Stove (IBS)
by Preheating of Biogas
V. K. Sukhwani, Nitesh Patidar, Abhishek Nagar
Govt. Ujjain Engineering College, Indore Road, Ujjain (Madhya Pradesh) 456010, India.
Corresponding Author: v_sukhwani@rediffmail.com, erniteshpatidar@gmail.com
Abstract
Biogas stoves generally do not fully utilize biogas due to high content of CO2 & moisture, which also
causes flame lifting. These stoves take more time in cooking as compare to LPG stoves. Main
objective of this work was to design an improved biogas stove for a small family base biogas plant
user. A biogas stove was modified by installing an arrangement for preheating of raw biogas.
Performance of Improved Biogas Stove (IBS) was evaluated on the basis of two factors i.e. (i)
Variation in diameter of burner ports and (ii) Preheating of biogas. In experimental procedure, a fixed
amount of water was heated in a specific utensil and temperature difference (ΔT) was measured after
time ‘t’. This process was repeated with and without modifications in stove. The maximum
performance improvement (43%) was evaluated with preheating of biogas on burner port of hole
diameter 0.30cm.
Key Words: Improved Design, IBS, DGS, Preheating.
Ti
NOMENCLATURE
ΔT
ΔT
Burner Port
ɸ
Diameter of
burner port
hole
Burner Port
BP
1.
LP
G
IBS
T
Liquefied
Petroleum Gas
Improved
Biogas Stove
Temperature
(00C=273.2K)
Introduction
Biogas is a renewable energy resource, which
is easily available and utilization of biogas is
helpful to decrease global warming effect. In a
biogas stove combustion of Methane (CH4)
takes place and it is converted into CO2 and
H2O. Methane is 21 times effective than
carbon Dioxide (CO2) in increasing global
warming. Designs of general biogas stoves
have some drawbacks like Low heating rate,
Time consumption more than LPG, Loss of
heat, Flame-lift, Content of CO2 and water
vapor etc.
Due to long heating time in biogas stove,
variable production rate of digester and other
problems of stove demotivates biogas users.
Water vapors present in biogas has a small but
noticeable impact on flame temperature,
Inflammability limits, lower heating value and
air-fuel ratio of biogas. In India, a patent was
1
ΔT
’
Initial
Temperature
Temperature
difference
without
preheating
Difference in
ΔT or (ΔT2ΔT1)
Tf
ΔT2
Final
Temperature
Temperature
difference
with
preheating
granted to Ucchrangraj Navalshannkar Dhehar
[2] on 17th April, 1969 for his initial design of
a biogas stove. A report on “Popular Summary
of the Test Reports on Biogas Stoves and
Lamps” was summarized by Dr. K. C.
Khandelwal and Dr. Vibha K. Gupta [7]. In
this research work, the specifications, testing
methodology for stoves and lamps, suited to
variable and high gas pressures of fixed dome
plants has been suggested.
1.1
Objectives of work:
Two main objectives of this work were as
follows (a)
To design an Improved Biogas Stove
with an arrangement of preheating of biogas to
increase its efficiency.
(b)
To evaluate performance of Improved
Biogas Stove on three burner ports of different
diameter of holes by measuring temperature
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difference of two cases i.e. with and without
preheating of biogas.
2.
Biogas plant
Experiments were carried out at a family based
biogas digester, which was installed in year
1996 at Mr. B.K. Patidar’s house located at
Chamble Chauraha, Bhanpura, Mandsaur,
Madhya Pradesh-458775, India. Contact:
+919424097177.
General information of biogas digester is
followingType of digester: Floating doam type.
Material: Dunk from two buffalos only.
Quantity of dunk: 20 kg per day.
Quantity of water added: 25 kg per 20
kg of dunk
Maximum Average temperature of
surrounding: In summer= 45 0C, In
winter= 250C, In Rainy= 300C
Composition: Methane=67%, CO2=32%,
other=1-2% (Measured by Syringe
Method)
3.
Design and manufacturing of
improved biogas stove
4.
IBS was manufactured in welding shop
on the basis of Engineering Design prepared by
project team (Figure-1). The main parts of
Improved Biogas Stove and key features are as
follows.
Upper Frame: It has been made of
cylindrical rods, in square shape of 30x30
cm2, Diameter of rod= 1.2cm, Weight=
1.1kg.
Prongs: 4 cantilever type Utensil stand
arms have been fitted at the midpoints of
all 4 frame rods. Length=8cm,
Width=2cm,
Thickness=0.4cm,
Weight=0.3kg.
Stand legs: Two strips have been joined
perpendicularly to make a stand. Each
strip Height=12cm cm, Width=2 cm,
Thickness=0.2cm, No. of legs= 4, Total
weight= 0.6 kg, Total weight of frame =
2kg.
Burner unit: It consists of burner
manifold, mixing tube and burner ports. In
mixing tube, the mixture of gas and air is
prepared.
Key feature: Burner unit is adjustable by a
nut-bolt arrangement at the opposite side of gas
entry. It can be moved up and down to set up a
suitable distance between utensil’s bottom and
flame to confirm the full utilization of heat
even at low supply of gas. Nuts:
Diameter=0.4cm, Type: Hexagonal, Bolts:
Nos. 2, Diameter= 0.4cm, Height=4cm
Manifold: (Fig. 3.3) Inner diameter=3.4
cm Outer diameter=7.5 cm
Thickness=0.25cm,
Height= 1cm to 5cm
Key feature: At the end of mixing tube the
inner part of manifold is in curved shape;
it reduces the velocity of the air-gas
mixture. Slow entry of charge reduces the
chances of Flame Lifting and gives better
flame stabilization.
Mixing tube: Length= 10.5cm, 2 holes of
size 1.5x2.5 cm2 at the beginning of tube
for the entry of air, Inner diameter=1.9cm,
Outer diameter=2.4cm(Fig 3.2)
Burner Ports: The total area of the burner
port is limited by the need to prevent flame
lift. Requirements of a good burner port
are:
Port No.1: weight= 140 gm, Diameter of hole
= 0.18cm
Port No. 2: weight= 120 gm, Diameter of hole=
0.30cm
Port No. 3; weight= 150 gm, Diameter of hole=
0.50cm
Supply Tube: It is a single valve
consisting tube of length 30cm. At one
end, preheating tube has been connected
and other end remains closed. At midpoint, it has a hole of 1 cm diameter to
attach a valve.
Key feature: This tube can also be used to
connect an LPG or biogas supply tube.
Valve: A simple LPG stove valve was used.
A switch was attached to turn the valve
(ATC Gold). Type: LPG Valve. Valve
consists of - Excluded brass forging, 12mm
Taper plug, 34mm Spindle Brass Screw &
Steel Spring.
Key features: It is easily available in market
and can also be used for both of the gases i.e.
biogas and LPG.
Pre-Heating Tube: Length=87cm,
Inner diameter=0.3cm, Helical ring: No.
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of turns=2, Height of turns= 1-2 cm,
Length of turns=55 cm
Key features: It helps in utilization of radiant
heat from burner ports to pre-heat biogas.
Moisture content in biogas is heated by this
method, which leads to convert it into low
pressure steam and hence heat efficiency is
increased. Thus, the chances of corrosion of
valve, supply tube and mixing tube gets
minimized. Preheating also minimize ignition
temperature of biogas.
5.
Performance evaluation of improved
biogas stove
IBS was mainly designed for cooking
purpose, so the performance measurement was
carried out by heating a fixed amount of water
in a specific utensil of stainless steel and
measuring temperature difference after time ‘t’
on a constant discharge flow and pressure of
biogas. This process has been repeated before
and after a modification in stove.
4.1
Required items for experiments:
a)
Stainless Steel Jar: Cylindrical jar of
Height=15cm,
Diameter=12.5cm,
Thickness=0.03cm
b)
Thermometer: Mercury thermometer
of maximum capacity of 110oC (Manufactured
by Vertex Deluxe).
c)
Electronic watch.
4.2
Experimental Set Up: Temperature of
biogas was measured before entering
preheating tube. After preheating of biogas,
temperature was measured. Flow of preheated
5.1
Comparison of performance of the
Improved Biogas Stove on BP-1, BP-2 and
BP-3 without any modification (Figure-2 &
3 and Table-1): This experiment was
conducted on 29/04/2014 at 09:00 PM and
conditions were as follows-
biogas is controlled by valve. A jar of steel
filled up with water was kept on stove. Initial
temperature (Ti) of water was measured by
thermometer. After time‘t’, final temperature
(Tf) of water was measured (Figure-1).
4.3
Experimental
Procedure
for
Performance Evaluation of Improved
biogas Stove (IBS): Preheated biogas was
used to evaluate the performance of IBS by
heating water.
Different cases and
measurements have been mentioned in section
4.4 and also shown in tables 1-5. These steps
were followed to perform evaluation
experiments.
a) A steel jar was filled with 1 liter of water
and the initial temperature of water i.e. Ti
was measured by thermometer.
b) The temperature, pressure and flow of
biogas and surrounding temperature were
measured.
c) Water was heated for time ‘t’ i.e. 1min,
3min, 5 min, 10min etc.
d) Final temperature of water after heating i.e.
Tf was measured.
e) Steps 2 to 5 were repeated with and without
modifications, so that observations could be
compared. Observations and readings have
been shown in table 1 to 5.
6.
Experiments
performed
on
improved biogas stove in different cases
Experiments were conducted for four different
cases. Observations have been mentioned in
Section 5.1 to 5.4.
Surrounding temperature: 320C
Temperature of untreated biogas: 310C
Pressure of biogas: 1 atm
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5.2
Comparison of performance of
Improved Biogas Stove (IBS) with and
without preheating of biogas on BP-1
Surrounding temperature: 31 0C
Temperature of biogas: 32 0C
Temperature of biogas: 35 0C
Pressure of biogas: 1 atm
Flow of biogas through supply tube:
4Ltr/min
(Figure-2 & 3 and Table-2): This experiment
was conducted on 28/04/2014 at 8:00 PM and
conditions were as follows -
5.3
Comparison of performance of IBS
with and without preheating of biogas on
BP- 2 :
5.4
(Figure-2 & 3 and Table-3): This
experiment was conducted on 28/04/2014 at
9:00 PM and conditions were as follows Surrounding temperature: 31 0C
Temperature of biogas: 32 0C
Temperature of biogas: 35 0C
Pressure of biogas: 1 atm
Flow of biogas through supply tube:
4Ltr/min
5.5
Comparison of performance of IBS
with and without preheating of biogas on
BP-3 (Figure-2 & 3 and Table-4): This
experiment was conducted on 29/04/2014 at
8:00PM.
Surrounding temperature: 31 0C
6.
achieved on performance evaluation of
Improved Biogas Stove in different cases as
mentioned in Section 5.
Results and discussion
Section 6.1 to 6.3 depicts graphical
representation and observations of results
Temperature of biogas: 32 0C
Temperature of biogas: 35 0C
Pressure of biogas: 1 atm
Flow of biogas through supply tube:
4Ltr/min
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6.1
Performance evaluation of IBS with
variation in diameter of burner ports
without preheating of biogas: Also refer
Section-5.1, Table-5 and Figure-4.
Biogas Stove. A better flame stability with less
sound and less flame lifting were observed in
BP-2.
Graphical representation in Figure-5 and
Figure-7 indicate that preheating of biogas on
BP-1 and BP-3 should not be recommended for
household use. Figure-6 shows that BP-2 can
be recommended for household use of IBS
with preheating of biogas and also, preheating
of biogas, less flame-lifting and limited noise
of combustion were observed. The results also
indicate that there is always an improvement
in performance of IBS due to preheating only,
but there is not a directly proportional relation
between the diameter of burner port and the
performance improvement of IBS with
preheating only. (Figure-8)
As shown in Figure-5, Observations of graph
depicts that there is no directly proportional
relation between the diameter of burner port
and the performance improvement of IBS in
case of “without any modification”. BP-2
(ϕ=0.3cm) can be suggested for household use
without any modification in ordinary biogas
stove or without preheating in Improved
6.2
Performance evaluation of IBS with
preheating of biogas: Also refer Section 5.2
to 5.4, Table-6 and Figure-5, 6 & 7.
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8.3 Heat efficiency of utensil may differ per
type of material.
5ml
syringe
7.
Precautions during experiments for
performance evaluation of improved biogas
stove
7.1 Temperature and pressure of surroundings
were almost constant in each case of
experiments and observations.
7.2 Quantity and initial temperature of water,
steel jar and heat up time were almost
same for two cases which are compared to
measure the effect of each specific
modification.
7.3 Flow rate, temperature and pressure of
supplied biogas were maintained almost
constant in each of two cases, which were
compared to measure the effect under
specific conditions and type of
modification.
7.4 Gap between the bottom of steel jar and
the burner port was fixed (in experiments
it was approx. 3.5cm).
8.
Limitations
of
experimental
procedure of performance evaluation of IBS
During the experiments, reasonably good
precautions were adopted, but limitations are
mentioned below 8.1 Biogas production rate of digester is not
constant throughout the day and the year
as well.
8.2 Biogas production rate and quantity of
CO2 and CH4 in biogas depends on the
type of raw material used in digester.
9.
CONCLUSION: Following major
points can be concluded from this research
work on Design and Performance Evaluation
of Improved Biogas Stove (IBS).
9.1
Burner port of larger diameter (0.50cm
in our case) is recommended for the better
performance of Improved Biogas Stove
without preheating or without any
modification in an ordinary biogas stove.
9.2
Burner port of medium range diameter
(0.3 cm in our case) is recommended for better
performance of Improved Biogas Stove with
preheating of biogas. It also provides better
flame stability and sound control of gas
combustion.
9.3
Total Cost of IBS was ₹614 and
fabrication time was 1 hour. Time and cost can
be reduced by manufacturing this Improved
Biogas Stove on a large scale.
9.4
Future recommendation for the work is
evaluation of Improved Biogas Stove with
preheating of biogas can be carried out with
some other burner ports of different diameter
of hole and content of CO2, H2S and moisture
can be reduced by further modifications in this
biogas stove.
References
1. National Biomass Cook stoves
programme (NBCS) of Government of
India, Ministry of New and Renewable
Energy.
Website:
http://www.mnre.gov.in/schemes/dece
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2.
3.
4.
5.
6.
cookstoves-initiative/, (accessed 15
Apr 2014).
Uchhrangraj Navalshankar Dhebar
(1969), Chairman, Khadi and Village
Industries Commission, Bombay,
India, “Burners Particularly for
Biogas and Lamps using such
Burners”, Specification No. ***688,
Application accepted on 17th April,
1969. An Indian Patent granted by The
Patent Office, Calcutta, India.
Dr. D. Fulford (1988), “A Handbook
on Running a Biogas Programme”,
©Intermediate
Technology
Publications, 103-105 Southampton
Row, London WC1B 4HH, UK, 60-67
Dr. D. Fulford (1996), “A short Course
on Biogas Stove Design”, Kingdom
Bioenergy Limited, University of
Reading, U.K.
WORGAS®, Energy Transformation
Technology, “Gas Burner Technology
& Gas Burner Design for Application”
J.N. Shrestha (2004), “A Final Report
on Efficiency Measurement of Biogas
Stoves”, submitted to Biogas Support
Partnership Nepal submitted by Center
for Energy Studies, Institute of
Engineering Tribhuvan University,
Pulchowok, Lalitpur.
7. Dr. K. C. Khandelwal and Dr. Vibha K.
Gupta (2009), “Test Reports on Biogas
Stoves and Lamps prepared by testing
institutes in China, India and the
Netherlands”,
SNV
Netherlands
Development
Organization,
The
Hague, The Netherlands.
8. BIS.2002. IS 8749:2002 (Reaffirmed
2008) Biogas stove-specification
(Second Revision).ICS 97.040.20, BIS
2002. Bureau of Indian Standards,
Manak Bhavan, 9 Bahadur Shah
JafarMarg, New Delhi 110002, India.
9. AutoCAD 2014: Student Version, An
Autodesk
Product,
website:
www.autodesk.com, (accessed 5 Apr
2014).
10. Wikipedia, the Free Encyclopedia.
Website:
www.en.wikipedia.org,
(accessed 15 Apr 2014).
11. The University of Adelaide, South
Australia 5005, Australia,
12. Tel: +61883134455 and Website:
www.adelaide.edu.au/biogas/,
(accessed 20 Apr 2014).
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Empowering Rural Women through Renewable Energy Technologies
Diksha Srivastava1, Deepak Sharma2 and Kapil K Samar3
1,2
Department of Renewable Energy Engineering, Udaipur
3
Biogas Development and Training Centre, Udaipur
Email: dkshme@gmail.com; Phone No.: +91-7597130060
Abstract
There is no denying the fact that women in India have made a considerable progress in decades of
Independence, but they still have to struggle against many issues for leading a sustainable life. This is
mainly because they are not only the producers but also managers of food, water, fuel and fodder, etc.
Women empowerment is the most critical issue of the present time. If women, particularly the rural and
tribal women are encouraged and educated about the appropriate and judicious use of energy resources,
problems such as food security, energy crises and environmental degradation could be minimized. The
focus of this research paper therefore, is on the women empowerment through the adaptation of various
renewable energy technologies developed in the recent times to lead an easy, healthy and independent
life. In India, about 40% of the total energy consumed is in rural areas, either in the form of wood, agrowaste or cattle dung used for cooking or lightening. These domestic activities are mainly considered as
women’s task in Indian context. By educating and making women adopt Renewable Energy
Technologies, they can be spared from the problems such as fuel wood collection, walking kilometers in
search of water; preparing cattle dung cakes, etc. The time which she devotes in all such works can be
utilized to reduce drudgery and in gaining occupations; empowering women not only economically but
also socially.
Keywords: Women empowerment, Renewable energy technologies, Sustainable life, energy security
1.
Introduction
The most famous saying said by the Pandit
Jawaharlal Nehru is “To awaken the people, it is
the women who must be awakened. Once she is
on the move, the family moves, the village moves,
the nation moves”. In India, to empower the
women, she should be made strong not only
physically but also mentally and socially. For
this, the education should be started at home
from childhood, because the upliftment of
women needs healthy family; resulting in the
holistic development of the nation. Since
Independence, women in India have made a
considerable progress, but they still have to
struggle against many issues for leading a
sustainable life such as struggle against potable
water, for which they have to walk miles;
struggle against fuel wood, for which they have
been denied education and have to go to forest
or lonely shrubby places; etc.
Energy availability, both in adequate quantity
and quality, is a pre-requisite to sustain targeted
economic growth and the desired levels and
speed of social development. There are number
of unit operations in domestic, agriculture,
transportation and industrial sector consuming
bulk of conventional energy sources. In India,
about 40% of the total energy consumed is in
rural areas, either in the form of wood, agrowaste or cattle dung. At domestic level the
energy is consumed for cooking, lightning,
drying & dehydration and other thermal heat
applications where renewable energy sources
can easily be integrated for energy conservation.
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There is significant potential for application of
Renewable Energy Technologies in Rural India.
If women, particularly the rural and tribal
women are encouraged and educated about the
appropriate and judicious use of energy
resources, problems such as food security,
energy crises and environmental degradation
could be minimized.
Women are not only the producers but also
managers of food, water, fuel and fodder, etc. By
educating and making women adapt these
technologies, drudgery will be reduced and
women will be gaining occupations;
empowering them not only economically but
also socially. Few of these Renewable Energy
Technologies, available commercially, which
will help women in their day to day activities
are:
2.
Solar Energy
Solar energy is a clean and unlimited source of
energy. Capturing the sun's energy for light,
heat, hot water and electricity can be a
convenient way to save money, increase selfreliance, and reduce pollution. Solar
technologies can be used to produce electrical or
thermal energy. It is estimated that solar energy
equivalent to over 15,000 times the world's
annual commercial energy consumption reaches
the earth every year. India receives solar energy
in the region of 5 to 7 kWh/m2 for 300 to 330
days in a year. This energy is sufficient to set up
20 MW solar power plants per square kilometre
land area. The solar thermal energy for cooling,
heating, steaming and drying and solar PV for
power generation can economically provide
energy where the distance is too great to justify
new system. Solar electric systems are used to
provide electricity for lighting, battery charging,
small motors, water pumping, and electric
fences etc.
2.1 Solar Cookers
Box type solar cookers are capable of cooking
different types of food including rice,
vegetables, chicken, fish, and for steaming,
roasting, boiling etc. It works as an
airtight box with double glass covers. A reflector
is placed over it for boosting the solar
radiation and thus its temperature increases.
Because of its simplicity and ease of
handling, the box type solar cooker has found
wider acceptance especially in rural areas.
Whereas, Dish or Parabolic solar cookers, have
an aperture diameter of 1.4 m and focal length
0.28 m. The reflecting material used for their
fabrication is anodized aluminium sheet which
has a reflectivity of over 75 per cent. The
tracking of the cooker is manual and thus has to
be adjusted after every 15 to 20 minutes during
cooking time. It has a delivering power of about
0.6 kW which can boil 2 to 3 L of water in half
an hour.
Solar Box Cooker
Concentrated Cooker
Solar
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day. IREDA provides the loan to the commercial
agencies for the promotion of installation of the
solar hot water systems. Besides this, many state
governments have been giving special subsidies
to domestic users of the solar water heaters of the
capacity of 100 litres per day capacity.
2.2 Solar Water Heating System
These systems are equipped with flat plate
collectors (FPC) with built in channels or riser
tubes attached (ETC) to the absorber sheet. With
a black paint coated on the absorber plate, the
water can be heated up to a temperature of 60°
to 90°C, while in selectively coated system the
temperature of water can be raised from 85° to
100° C. Presently, the solar water heating
systems are used for domestic, commercial and
industrial
applications.
2.3 Solar Dryers
FPC type Solar Water Heater
ETC type Solar Water Heater
A temperature of 60° C is sufficient for domestic
use and as such black paint coated absorbers are
normally
used
in
such
domestic solar water heating systems. Solar
water heating systems have capacity ranging
from 100 litres per day to over 200,000 litters per
The solar drying systems have many
applications; both at domestic and industrial
level. The various designs of direct as well
indirect type solar dryers for drying vegetables,
fruits, grains, fish, timber, chemicals and other
industrial products etc. are available.
.
Solar tunnel dryer for industrial purpose
Solar domestic dryers
These dryers not only save energy but also save
lot of time, occupy less area, improve quality of
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the dried product, make the process more
efficient and protects environment also. Solar
dryers circumvent some of the major
disadvantages of classical drying. Solar drying
can be used for the entire drying process or for
supplementing artificial drying systems, thus
reducing the total amount of fuel energy
required. Solar dryer is a very useful device for:
Dairy industries for production of milk
powder, casein etc.
Seasoning of wood and timber.
Textile industries for drying of textile
materials.
Agriculture crop drying
Food processing industries for dehydration of
fruits, potatoes, onions and other vegetables
2.4 Solar Lantern and Street Lighting
System
A typical solar lantern consists of a small
photovoltaic module, a light source, a
high frequency inverter/ballast, battery, charge
controller and appropriate unit. During
the day hours, the module facing south is placed
in the sun and it converts the solar
radiation into electricity and charges the battery
which is connected to the lantern through
a cable. In the evening, the lantern with the
charged battery is disconnected from the
module and is available for indoor or outdoor
use. Whereas; the solar PV based street lighting
system has a pole, a battery enclosure, a battery,
a LED or CFL based light and Photo voltaic
module. During the day hours, the module facing
south is charges the battery. In the evening, when
voltage through module gets down, the
controller automatically starts the light for
lighting the street or roads. In the morning, when
module starts to produce power, the controller
automatically power off the light.
Solar Lantern and Street Lighting System
3.
Unnat Chulahs
In rural households, food is generally cooked on
clay stoves called ‘Chulhas’. Chulhas use
biomass in the form of fuel wood as fuel. A
family of 5 to 6 persons requires about 8 kg fuel
woods every day. Surveys show that, on an
average, the domestic fuel consists mainly of
agricultural residues and cattle dung,
supplemented by fuel wood to the extent of
about 40%. However, these traditional chulhas
are very wasteful as they use only 10% of the
total heating potential of the fuel burnt in them.
A more serious disadvantage of the traditional
chulhas is that they produce a lot of smoke, soot
and unburnt volatile organic matter, which not
only blacken the pots and the walls of the
kitchen, but also lead to Indoor Air Pollution
(IAP). It adversely affects the health of the rural
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householders by slow health degradation and
setting the onset of killer respiratory diseases.
In present, two models of Unnat Chulhas
namely, Udairaj and Chetak have been
developed by Department of Renewable Energy
Engineering, CTAE, Udaipur. Chetak is a onepot model whereas Udairaj is two- pot model of
Unnat Chulhas. These models can also be called
as modified traditional chulhas, in which energy
loss due to radiation and convection are
minimized; resulting in saving of fuels. Like
traditional chulhas; these Unnat Chulhas are also
made from bricks and cement or clay. Smoke
can be exhausted out of the house with the use of
an outlet. Due to this, the harmful effects due to
smoke are greatly reduced. Their life span is
estimated to be of approximately 5 years.
Environmental changes such as rainfall, etc.
didn’t exert much change on their structure. The
efficiency of Unnat Chulhas was also measured
in actual operation which indicates about 22
percent thermal efficiency. It is also observed
that on an average 950 kg of fuel wood can be
saved by using one Unnat Chulhas in a year.
Udairaj Unnat Chulha
4.
Biogas Technology
The main energy source for generating Biogas is
organic matter. Generally, biogas is prepared by
the anaerobic digestion of cattle dung and water
mixed in equal quantities. Biogas comprises of
60-65 percent methane (CH4), 35- 40 percent
carbon dioxide (CO2), 0.5-1.0 per cent hydrogen
sulphide (H2S) and traces of water vapours. It is
almost 20 percent lighter than air. Biogas cannot
be converted into liquid like liquefied petroleum
gas (LPG) under normal temperature and
pressure. The slurry coming from digester is rich
in nitrogen which is an essential nutrient for
plant growth. Biogas is an easy and healthy
cooking fuel since methane emissions from
untreated cattle dung and biomass wastes can
also be avoided. Since there is no pollution from
biogas plants, these are one of the most potent
tools for mitigating climatic change and being
earth saviors.
Biogas Lamp being used Biogas Plant used
for domestic purpose
The energy liberated by Biogas is not only used
for cooking but can also be used for lightning
lamps and for power generation. Biogas lamps
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are commercially available for lightning
purpose. Power could be generated using biogas,
using Biogas Genset. Subsidy is also provided
by Government of India for setting up biogas
plant for domestic purposes.
Biogas being used for cooking
Properties of Biogas which make it an excellent
fuel are:
Biogas is a non-toxic, colourless and
flammable gas.
It has an ignition temperature of 650 – 750
°C.
Its density is 1.214 kg/ m3
About 60 percent methane and 40 percent
CO2 content
Calorific value is 20 MJ/m3 (4700 kcal).
Almost 20 percent lighter than air
It liquefies at a pressure of about 47.4
kg/cm2 at a critical temperature of - 82.1°C.
Purified biogas (bio-methane) has a higher
calorific value in comparison to raw biogas.
There are two designs of biogas plant popular in
India:
(a)
Floating Gas holder type.
(b)
Fixed dome type
(a) In floating drum type design, the digester is
an
underground
tank
constructed
in brick masonry, stone masonry, RCC or
ferrocement. It has an inverted metallic drum
which acts as gas holder. The gas produced in
digester is collected in gas holder at a
constant pressure depends on the weight of gas
holder. The merits of this design are:
Gas is supplied at constant pressure
It has a provision for breaking scum.
Any local mason can construct the plant.
At high water table area, horizontal plant
can be constructed.
Different models comes in category are
KVIC vertical and horizontal, Pragati
Model, Ganesh Model and Ferrocement
digester.
(b) The fixed dome type biogas plant is a dome
shaped
underground
construction. The masonry gas holder is an
integral part of the digester called dome.
The gas produced in the digester is collected in
dome
at
variable
pressure
by
displacement of slurry to inlet and outlet. The
merits of these designs are:
The construction is made entirely of bricks and
cement which are locally available. Steel gas
holder is not required.
.
As there is no moving part, the maintenance
cost is minimised.
Less effected by low temperature.
The space above the plant is usable as the
plant is under ground.
Other materials along with dung slurry can
be charged.
The scope of biogas has been enlarged by
coupling all type of organic waste along with
dung recycling including fruits & vegetables
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waste. Presently biogas is not only recognized
as gas production from dung recycling but also
it is also known as all organic waste recycling
for resource recovery system in terms of biogas
& enriched manure. In fact there is no waste; all
waste can be used as source for wealth. In India
there is good potential of waste material, which
can easily be converted in biogas.
3
Water
Solar water heating,
Heating
biogas, Unnat Chulhas
4
Drying
Solar dryers
5
Electricity
Solar
photovoltaic
production
system, biogas genset
To conclude, introducing women to the
renewable energy technologies can mitigate
drudgery, reduce environmental damage,
support meeting of their basic energy needs and
foster productive activities for their economic
and social upliftment.
References:
Mode of Operation of Biogas Plants and
their Uses
5.
Summary
In contrast to conventional energy sources, the
potential supply from renewable is essentially
infinite and largely free of external costs. Some
Renewable Energy Technologies are already
competitive with conventional energy sources,
for example biomass or biogas applications.
Renewable energy provides greater flexibility.
Various daily household applications that can be
used by women in their day to day activities are
as mention underS.N. Application Renewable Energy
Technology
1
Cooking
Biogas, Solar Cooker,
Unnat Chulhas
2
Lighting
Solar Home lighting,
Solar lantern, Solar
Street Light, Biogas
Lamps
1. Bansal, N.K., Hake, J., 2000. Energy needs
and supply options for developing countries.
Proceedings of the World Engineer's Convocation (Energy section), Hanover, pp. 6596.
2. Bernow, S., Dougherty, W., Duckworth, M.,
Brower, M., 1998. An integrated approach to
climate change policy in the US electric
power sector. Journal of Energy Policy 26
(5), 375-393.
3. Grover P D (2004) Characterization of
biomass for energy generation. Biomass
Management for energy purposes – issues
and strategies, Proceedings of the national
seminar, SPRERI, Anand, Gujarat: 134-174.
4. Hall D O, Rosillo-Calle F, Woods J (1991).
Biomass, its importance in balancing CO2
budgets. In: Grassi G, Collina A, Zibetta H,
editors. Biomass for energy, industry and
environment, 6th E.C. Conference Elsevier
Science, London, : 89-96
5. https://www.iaspaper.net/womenempowerment-in-india/
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AN EXPERT SYSTEM FOR THE ESTIMATION OF DIRECT SOLAR
RADIATION IN INDIAN REGION
1
R. K. Tomar, 2N. D.Kaushik
Department of Civil Engineering, Amity University Uttar Pradesh, Noida -201313, India.
1
Centre for Energy Studies, Indian Institute of Technology, Hauz Khas, New Delhi-110016, India.
E-mail address: rktomar67@gmail.com
Abstract
In this paper an expert system is developed for the estimation of direct solar radiation in Indian
region. The basic premise is to have a software tool that shall provide comprehensive support to
general users working in assorted fields like climatology, solar energy utilization and environmental
impact assessment. The approach involves artificial neural network model and is envisioned to provide
general users the power of an expert. It can also be adapted easily to change of climatic conditions.
Keywords: Solar radiation, Expert system, Artificial Neural Network.
1. Introduction
consideration of parameters related to climate
Radiant energy from sun is vital for life on our
and weather phenomena. In recent years, the
planet. It determines the surface temperature of
models of estimation of solar radiation using
earth as well as supplies all energy for natural
fuzzy random variables have been developed
processes both on earth’s surface and its
(Gautam & Kaushika 2002) which has defined
atmosphere. The solar radiation estimation is
the Clearness Index(CI) of extra-terrestrial
required in many disciplines such as
radiation that reaches the earth’s surface when
Climatology, Solar energy utilization &
the sky above the location of interest is
Environmental impact assessment. All the users
obscured by the cloud cover or otherwise. More
of solar resource do not have expertise and/or
recently, Tomar et al. 2012, have used the ideas
easy access to the solar resource data of the
of neural nets, parallel distributed processing
location of their requirement. Furthermore, the
and connectionist network to determine
solar radiation is generally variable and
Clearness Index. This approach is often termed
enormously inconsistent and in practice the
as Artificial Neural Network (ANN) modeling.
models of estimation of solar radiation are often
These models owing to their rigor are useful for
used.
the expert system approach.
In this paper we have made an effort to widen
3. The Algorithm
the usability of the models for a larger crossSolar energy is in the form of radiant energy
section of the users. This approach may be
and the radiation has nearly fixed intensity
referred to as the expert system approach. The
outside the earth’s atmosphere. It is referred to
expert system is a software tool that is
as Extra-terrestrial radiation. It is characterized
envisioned to provide general user the power of
by the solar constant Isc. It is defined as the
an expert.
energy received from the sun per unit area
2. Model Approach
placed perpendicular to the sun rays outside the
Several models have been developed for the
earth’s atmosphere at sun-earth mean distance.
estimation of solar radiation at different
Its value in the present software is taken to be
geographical and meteorological conditions
1364 W/m2 (Mishra et al. 2008 and Tomar et al.
(Reddy 1971; Hottel 1976; Sabbagh et al. 1977;
2012). Owing to the variation in the sun-earth
Barbaro et al.1978; Goh 1979; El-Nashar 1981;
distance, Isc varies during the year round cycle.
Ogeman et al. 1984; Supi & Van Kappel 1998:
The value of Isc on the nth day of the year (n =
Mishra et al. 2008,). These models lack detailed
1 for Jan 1), Io may be calculated as follows
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360n
Io=Isc 1+0.034cos 365.25
The solar radiation is received at earth’s surface
after being subjected to the mechanisms of
attenuation, reflection and scattering in the
atmosphere which in turn are the functions of
solar zenith angle or the solar incident angle on
the horizontal plane, the declination angle and
the hour angle(time of the day). The radiation
received without change in the direction is
referred to as beam radiation or direct solar
radiation. As a first approximation, the solar
beam radiation intensity can be obtained from a
simple clear day model by Hottel 1976. The
model is based on atmospheric transmittance
calculation using the 1962 US standard
atmosphere and has been subsequently
corrected for climate conditions. So we have:
al. 2012 we have investigated the variation of
Clearness Index as a function of latitude,
longitude, time of the day and day of the year.
The mean monthly variation of Clearness Index
as a function of latitude is shown in fig. 1.
So the grey day radiation may be determined by
multiplying the solar radiation values with the
Clearness index defined as follows:
Clearness Index (CI) =
Sbnm
Sbnc
Sbnc=Io ao+a1e-ksecθz
Fig. 1: Clearness Index graph
where the parameters ao, a1 and k are the
functions of height above sea level in
kilometers and the climate of the location
(Duffie & Beckman 1991). The climate
corrected calculated clear day values (Sbnc) are
often higher than the observations (Sbnm). The
deviations exhibit variability with time of the
day, day of the year and meteorological
parameters such as rainfall, relative humidity,
mean duration of sunshine. A parameter
characteristic of the weather phenomenon was
referred to as Clearness index (Tomar et al.
2012). Following the neural network analysis
procedure of Mishra et al. 2008 and Tomar et
Fig. 2: Flowchart of the program execution
4.
Computational Flowchart
From the above algorithm it is clear that the
solar radiation value at a particular location is
the function of the height above sea level in
kilometers, the latitude of the location, day of
the year, time of the day and the Clearness
index. Using these input parameters,
computational process is illustrated in the
flowchart depicted in Fig: 2.
5. Structure of the Expert System
The graphical user interface (GUI) of the expert
system is illustrated in Fig. 3. Upon providing
the values in the input boxes, the press of
calculate button shows the results in the output
box which can either be printed or saved in a
text file.
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Fig. 3: GUI of Expert System
6. Validation of results
With a view to examine the compatibility of the
predictions of the expert system approach, we
have investigated the RMSE (%) values for the
stations spread all over India. The RMSE (%)
ranges for most of the stations used in the
analysis were in the range of 13.36 - 24.64 for
direct solar radiation. The range is of the right
order of magnitude in view of the prediction
errors reported by earlier researchers, for
example 22.73% reported by NASA SSE data
sets. However, it was noticed that the RMSE
(%) values of costal locations are relatively
higher owing to intensive monsoon activities
and their effect on observed data.
7. Summary and conclusion
The estimation and prediction of direct solar
radiation is useful for a wide spectrum of users
such as energy planner, engineers, architects,
solar scientists and researchers. In this paper an
artificial neural network based computational
models for the estimation and prediction of
solar radiation in Indian zone is presented. The
analysis is based on the data of the stations
cover by far the widest range of latitudes
(8.480N to 34.080N) and longitudes (72.180E to
92.720E) spread over the entire Indian
continent. The contour maps of atmospheric
clearness index as a function of latitude, month
of the year and time of the day are drawn.
Finally the methodology for the prediction of
direct solar radiation at an arbitrary location
using these maps is developed. The
computational scheme is embedded in a
graphical user interface designed to be usable,
as an easy to understand expert system, by a
wider cross section of investigators. The
computational results obtained from GUI
exhibit good compatibility with earlier models
and recent measurements carried out at
arbitrary locations in Indian region.
References
1. Barbaro S., Coolino S., Leone C., &
Sinagra E. (1978). Global solar radiation in
Italy. Solar Energy, 200, 431.
2. Duffie J. A. & Beckman W. A. (1991).
Solar engineering of thermal processes.
(New York: John Willey & Sons).
3. El-Nashar A. M. (1981). Solar radiation
characteristics in Abu Dhabi. Solar Energy,
47(1), 49.
4. Gautam N. K. & Kaushika N. D. (2002). A
Model for the Estimation of Global Solar
Radiation Using Fuzzy Random Variable.
Journal of Applied Meteorology, Vol. 41
No. 12, 1267-1276.
5. Goh T. N. (1979). Statistical study of solar
radiation in formation in an equatorial
region (Singapore). Solar Energy, 22, 105.
6. Hottel H. C. (1976). A sample model for
estimating the transmittance of direct solar
radiation through clear atmosphere. Solar
Energy, 18, 129.
7. Internet
World
Stats
–
http://www.internetworldstats.com/stats.htm
(last accessed on 19th May 2010)
8. Kaushika N.D., Tomar R.K. and Kaushik
S.C., 2014. Artificial neural network model
based on Interrelationship of direct, diffuse
and global solar radiations. Solar Energy
103,327-342.
9. Mishra Anuradha, Kaushika N. D., Zhang
Guoqiang, & Zhou Jin (2008). Artificial
neural network model for the estimation of
direct solar radiation in the Indian zone.
International Journal of Sustainable
Energy, 27:3, 95-103.
10. NASA
SSE
web
portal
<http://eosweb.larc.nasa.gov/sse/>.
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11. Ogeman H., Ecevit A., & Tasdemiroglu E.
(1984). A new method for estimating solar
radiation from bright sunshine data. Solar
Energy, 71, 307-319.
12. Reddy S. J. (1971). An empirical method
for the estimation of the total solar
radiation. Solar Energy, 14, 289.
13. Sabbagh J. A., Sayigh A. A. M., & ElSalam E. M. A. (1977). Estimation of the
total solar radiation from meteorological
data. Solar Energy, 19, 307.
14. Supi I. & Van Kappel R. R. (1998). A
simple method to estimate global radiation.
Solar Energy, 63, 147.
15. Tomar, R.K., Kaushika, N.D., Kaushik,
S.C., 2012. Artificial neural network based
computational model for the prediction of
direct solar radiation in Indian zone. J.
Renew. Sustain. Energy 4, 063146.
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Parametric study of Pump as Turbine-2: Variation of Diameter of
Impeller
Doshi A. V.1; Bade M. H, Sahu Rohit2
Mechanical Engineering Department, Sardar Vallabhbhai National Institute of Technology,
Ichchhanath, Surat-395007, Gujarat, India
2
Alpha College of Engineering and Technology, Beside Lincon Polymers, At Khatraj, Kalol Taluk,
Gandhinagar, Gujarat 382721
1
Abstract
Among renewable energy sources, for isolated power production, pump as turbine (PAT) are potential
energy source where energy is required mainly for lighting during night hours and may use for local
industry during day. However, in Indian situation, flow rate is always fluctuating over the years such as
water flow rate of streams are higher in rainy season and reducing toward summer. If impeller diameter and
speed of PAT are constant then there is significant loss in efficiency due to reduction in flow rate. However,
operating the PAT with different impeller diameters or speed, PAT can be operated without significant drop
in efficiency even at reduced flow conditions. In this paper, simple approach based on characteristics of
pump operated in reverse mode and affinity law is used to evaluate the best efficiency point with different
impeller diameters. For lower difference of impeller diameters, affinity law held good and predict the PAT
performance parameters with very small deviation.
Keywords: Pump as turbine, reverse mode operation of pump, affinity law, variable impeller diameter
conditions. Therefore, influence of impeller
diameter on the performance of PAT should be
1.
Introduction
Micro-hydro power can be one of the most
important alternatives to isolated rural
communities due to the advantages of
electrification and the associated progress, as
well as to improve the quality of life. It is one
of the most commercial hydroelectric power
technologies for rural electrification in world.
When the centrifugal pump works in reverse
mode it simply reduces the equipment cost and
can be used as substitute to conventional
turbine. Pump manufactures do not generally
provide the characteristic curves of their pumps
in reverse mode. Therefore, it is difficult to
select appropriate pump to run as turbine (Yang
et al. 2012). Additionally, throughout the year,
flow rate of available water streams generally
reduces as rainy season gets over in case of
small hydro plants. On the other side, the
maximum efficiency band for PAT is very
small, results in loss of efficiency due to
reduction in flow rate or load on the PAT, if
appropriate selection is not done. The impeller
diameter is one of the important parameter in
the selection of PAT for the specific site
studied in detail to avail the benefits of PAT for
variable operating conditions.
Yang et al. (2012) had performed experimental
and numerical investigation on impeller
trimming for pump as turbine. Experimental
research was carried out on a single stage
centrifugal PAT, performance curves of
original impeller, impeller after once and twice
trims were acquired. In another paper, Yang et
al. (2013) had carried out experimental work on
three different sizes of impeller, 215, 235
and 255 mm. The PAT efficiency, pressurehead, shaft-power, and flow rate at the BEP
are increased by 10.26%, 36.16%, 89.39%,
and 26.14%, respectively, due to increase in
impeller diameter ( from 215 to 255 mm).
Jain et al. (2015) had performed experimental
investigations for various impeller diameters.
The experiments were performed at constant
rotational speed of 1100 rpm with original
diameter (250 mm), 10% trimmed impellers
diameter (225 mm) and 20% trimmed diameter
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(200 mm). According to Gulich (2010) the
economical limitation of the trim ratio of large
pumps operational behavior should be
considered, since it may deteriorate if blade
shortening through trimming is excessive.
1.1
Objectives of the Current Study
Based on the above literature review and
available experimental facility in the laboratory,
the following objectives has been planned:
i. To perform the trials on a selected pump in
reverse mode (PAT) with impellers of
different diameters.
ii. To compare the performance of pump in
reverse mode at best efficiency point (BEP)
for different diameters.
iii. To verify the experimental parameters of
PAT for different diameters at BEP by
affinity law.
2.
Methodology:
The experimental and theoretical means are
applied to accomplish above Objectives.
2.1 Experimental analysis
A radial flow end suction type centrifugal pump
with impeller diameter 214 mm is selected for
reverse mode operation. The Pump parameters at
BEP are specified as: flow rate 15.28 lps, head
14.28 m, power input 2.9 kW, and efficiency 74 %
(shown in Figure 1). The experiment on selected
PAT with different impeller diameters are
conducted on an open loop type test setup. The
test setup consists of a feed pump to supply
water at high pressure to get necessary head and
flow. Feed pump is driven by an electric motor,
which is connected to variable frequency drive
(VFD). High pressure water is supplied to
centrifugal pump running as turbine through
piping arrangement. After imparting energy to the
impeller, this water is discharged into the sump
through a draft tube. Head across the feed pump
and PAT is measured using pressure transducers.
Inductive proximity switches are used to measure
feed pump as well as PAT speed. An
electromagnetic flow meter installed in line is used
to measure the flow rate. Detailed description of
this PAT test rig is given by Doshi (2017). In order
to avoid over cutting the impeller, it is
recommended that the trimming be done in steps
with careful measurements of the results. At each
stage, available experimental data can be used to
predict the performance parameter for the next
step and accordingly trimming diameter would be
decided. Therefore, the PAT is tested for three
different diameters viz. original impeller (ϕ 214
mm), 5% trimmed impeller (ϕ 205 mm), and 10%
trimmed impeller (ϕ 195 mm). The data generated
through experiments are processed for plotting of
the characteristic curves such as head, power, and
efficiency Vs. flow rate.
2.2
Theoretical Analysis of PAT
The affinity laws are derived from a
dimensionless analysis of three important
parameters that describe pump performance:
flow, total head, and power. The analysis is
based
on
reduced
impeller
being
geometrically similar and it is operated at
dynamically similar conditions or equal specific
speed. If that is the case then the affinity laws
can be used to predict the performance of the
pump at different diameters for the same speed
or different speed for the same diameter.
Current work is analyzing effect of different
impeller diameters on the performance of PAT.
Since in practice impellers of different
diameters are not geometrically identical, the
performance parameters in the pump
recommend to limit the use of this technique
to a change of impeller diameter. The
simplified affinity laws with assumptions of
similarity in the velocity triangles at inlet and
outlet of PAT at BEP for different impeller
diameter conditions used are:
Q2 D2
Q1 D1
3
H 2 D2
H1 D1
P2 D2
P1 D1
Where,
(1)
2
(2)
5
(3)
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D is Impeller diameter, m;
P is Power, kW;
H is Net head, m;
Q is Discharge, m3/s;
subscript 1 is Impeller inlet (Turbine mode);
subscript 2 is Impeller exit (Turbine mode)
3 Results and Discussions:
The experiments were performed on PAT with
three impellers of diameters viz. original
impeller (ϕ 214 mm), 5% trimmed impeller (ϕ
205 mm), and 10% trimmed impeller (ϕ 195
mm) at rotational speed of 1000 rpm. To study
the effects of impeller trimming on head,
power and efficiency at different discharge the
performance curves are plotted as shown in
Figures 3, 4, and 5. All three results are
superimposed in one single graph that will give
the clear information about performance
variation with trimmed impeller on PAT.
In the plots of head and output power Vs.
discharge (Figures 2 and 3), larger diameter
impeller curve is above that of lower from part
load to best efficiency point (BEP) and vase
versa in overload region. This indicates that
higher head is required to operate the PAT for
larger diameter PAT in part load region, on the
other hand, in over load region, higher head is
required to operate the PAT for lower diameter
PAT. Similar observation is equally valid for
output power Vs. discharge plot as shown in
Figure 3. The efficiency curve shown in Figure
4 for impeller diameters of original impeller (ϕ
214 mm), 5% trimmed impeller (ϕ 205 mm),
and 10% trimmed impeller (ϕ 195 mm)
indicates that at duty point efficiency of PAT is
maximum, in part load, and overload region is
dropping. In part load region, the efficiency
curve is steep whereas in overload region slop
of drop in efficiency curve is comparatively
small. With increasing in the impeller diameter
of PAT, it is observed from Figure 4 that the
peak efficiency (BEP) is shifting towards
higher flow rate. Further, this helps in operation
of PAT where flow rate is reduced. If flow rate
is dropped down, then it is always
advantageous to operate PAT at lower diameter
than the diameter at which it is running such
that it’s operating point for new condition will
match with the duty point. From Figure 4 it is
also devised that during selection pump for
turbine operation it is better to select a pump of
lower capacity and to operate it in the overload
region so during operation of PAT due to drop
in flow reduction in the efficiency is
comparatively very small.
Various parameters at BEP for different
impellers are summarized in Table1. It may be
noted that, the discharge, power output,
efficiency, and Head decreased by 12.5%, 27%,
1.22% and 12% respectively with 205 mm
diameter impeller. Further trimming result in
decrease of all the parameters but not in greater
extent. The decrease in parameter is causes due
to the large separations inside the impeller
passages with larger trimmed impellers.
Table 2 presents the performance parameters at
BEP determined by experiment and by affinity
law. From Table 2 it is seen that at lower
impeller diameter (ϕ195 mm) deviation in the
flow rate prediction is 9.7 %, head prediction is
3.5 % and power prediction is 2 %. For
impeller diameter, (ϕ205 mm) deviation in the
flow rate prediction is 0.5 %, head prediction is
9.3 % and power prediction is 11.2 %.
4 Conclusions:
In the paper, the state of art facility is
developed for testing the PATs with
sophisticated instrumentation and automatic
control systems. Based on PAT characteristic
curves obtained at various impeller diameter,
PAT can be operated optimally (without much
compromise of reduction in efficiency) to meet
with variable flow conditions. For lager
difference in diameter of impeller (small size
compared to original impeller diameter),
remarkable decrease in parameter is generally
observed, which is because of large separations
inside the impeller passages as the gap between
mouth of the casing and tip of the impeller
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2.
3.
4.
5.
Doshi, A., 2017. Influence of Inlet Impeller
Rounding and the Shape of Non-Flow Zones on the
Performance of Centrifugal Pump As Turbine.
Sardar
vallabhbhai
National
Institute
of
Technology, Surat, India.
Gülich, J.F., 2010. Centrifugal Pumps. 2nd Ed.
Springer-Verlag Berlin Heidelberg. 2nd Edition,
Springer-Verlag Berlin Heidelberg, Berlin.
Jain, S. V., Swarnkar, A., Motwani, K.H., and Patel,
R.N., 2015. Effects of impeller diameter and
rotational speed on performance of pump running
in turbine mode. Energy Conversion and
Management, 89, 808–824.
Yang, S.-S., Kong, F.-Y., Jiang, W.-M., and Qu, X.-Y.,
2012. Effects of impeller trimming influencing
pump as turbine. Computers & Fluids, 67, 72–78.
Yang, S.-S., Liu, H.-L., Kong, F.-Y., Dai, C., and Dong,
L., 2013. Experimental, Numerical, and Theoretical
Research on Impeller Diameter Influencing
Centrifugal Pump-as-Turbine. ASCE Journal of
Energy Engineering, 139 (4), 299–307.
12
8
4
0
0
2.5
Pressure
Guages
VFD
Panel
FeedPump
Control Valve
EddyCurrent
Dynamometer
Conrtol
Panel
G.L.
TorqueSensor
Pressure
Guages
2
Ground
level
Test Bed
25
1.5
1
0.5
0
0
5
10
15
Flow rate (lps)
20
25
Figure 3: Power Vs. Flow Rate characteristic
curves for PAT at different diameters
80
214 mm
205 mm
195 mm
40
20
0
0
5
PAT
Motor
10
15
20
Flow rate (lpm)
214 mm
205 mm
195 mm
60
ElectroMagneticFlowMeter
5
Figure 2: Head Vs. Flow Rate characteristic
curves for PAT at different diameters
Efficiency (%)
1.
214
mm
16
Head (metre)
References:
20
Power (kW)
becoming large. Testing of affinity law at
diameter variation with large data can be future
scope of work. This will increase the
applicability of PAT operating at different
diameters.
Draft
Tube
Ground
level
CommonSump
Figure 1: Schematic Layout of PAT Test Rig (Doshi
2017)
10
15
Flow rate (lpm)
20
25
Figure 4: Efficiency Vs. Flow Rate
characteristic curves for PAT at different
diameters
Table 1: Comparison of BEP parameters of different
impellers
Impeller
Q (lps)
H (m)
P (w)
Ƞ (%)
214 mm 16.716
205 mm 14.623
195 mm 14.074
11.561
9.704
9.276
1.309
0.944
0.838
69.090
67.862
65.505
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Table 2: Comparison of experimental and
analytical parameters at BEP
Efficiency Flow Rate
Head, (m)
Power, (kW)
Diameter
lps
(η)
mm
% Experiment
AffinityExperimentAffinity
Experiment
Affinity
214
205
195
69.09
67.86
65.50
16.716
14.623 14.69
14.074 12.64
11.56
9.70
9.27
10.60
9.59
1.309
0.944
0.838
1.05
0.822
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Renew your Inner Energy through Human Internal Energy Sources:
A Practitioner and Theoretical Approach
Shulbha Kothari, Shiv lal
Government Engineering College Banswara, India-327001
Corresponding Author: shulbha1986@gmail.com
Abstract
This work deals with the human being renewals, which are most important for the good health and
spiritual life. The global exergy phenomena can be utilized for human being is proved in this study.
It applies to performance indicators for individuals under physical activity based on the concept of
exergy destroyed and exergy efficiency.
1.
Introduction
You can renew your lease when it runs
out at the end of the year, you can renew your
driver’s license and license plate on your
birthday, you can also renew a library book
when you allotted them with it has expired. All
sorts of things get renewed in our everyday
lives when they run out or expire. They are
easy to renew because you don’t have to create
new one, you just renew the ability to use
whatever it is you are using.
You can apply the same principle
to natural resources. We use all kinds of natural
resources minerals, wood, coal, natural gas,
wind, water, plants, animals and many more,
some of these are renewable and some are nonrenewable. The difference is that some renew
at faster rates than others, making them more
sustainable than those that do not renew very
fast.
Renewable resources are resources
that are replenished by the environment over
relatively short period of time. This type of
resources is much more desirable to use
because often a resource renew so fast that it
will have regenerated by the time you have
used it up. Think of this like ice cube maker in
your refrigerator, as you take some ice out,
more ice gets made, if you take a lot of ice out,
it takes little more time to refill the bin but not
a very long time at all. Even if you completely
emptied the entire ice cube bin, it would
probably only take a few hours to ‘renew’ and
refill that ice bin for you. Renewable sources
in the natural environment work the same way.
Energy resources and their utilization
intimately relate to sustainable development.
In attaining sustainable development,
increasing the energy efficiencies of processes
utilizing sustainable energy resources plays an
important role. The utilization of renewable
energy offers a wide range of exceptional
benefits. There is also a link between exergy
and sustainable development. A sustainable
energy system may be regarded as a costefficient, reliable, and environmentally
friendly energy system that effectively utilizes
local resources and networks. Exergy analysis
has been widely used in the design, simulation
and performance evaluation of energy systems.
1.1 What Is Exergy?
Exergy is a thermodynamic concept, used for
many years within engineering analyses of
chemical and mechanical processes and
systems. Officially, exergy is defined as: “The
maximum useful work which can be extracted
from a system as it reversibly comes into
equilibrium with its environment.” (1)
The cardiopulmonary exercise test is
one of the most used tests to assess the
functional capacity of individuals with varying
degrees of physical training. To perform the
exergy analysis during the test, it is necessary
to calculate heat and mass flow rates,
associated with radiation, convection,
vaporization and respiration, determined from
the measurements and some relations found in
the literature. The energy balance allowed the
determination of the internal temperature over
time and the exergy variation of the body along
the experiment. Eventually, it was possible to
calculate the destroyed exergy and the exergy
efficiency from the exergy analysis. The
exergy rates and flow rates are dependent of
the exercise level and the body metabolism.
The results show that the relation between the
destroyed exergy and the metabolism is almost
constant during the test, furthermore its value
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has a great dependence of the subject age.
From the exergy analysis it was possible to
divide the subjects according to their training
level, for the same destroyed exergy, subjects
with higher lactate threshold can perform more
work.
Exergy analysis is applied to assess the
energy conversion processes that take place in
the human body, aiming at developing
indicators of health and performance based on
the concepts of exergy destroyed rate and
exergy efficiency. The thermal behavior of the
human body is simulated by a model
composed of 15 cylinders with elliptical cross
section representing: head, neck, trunk, arms,
forearms, hands, thighs, legs, and feet. For
each, a combination of tissues is considered.
The energy equation is solved for each
cylinder, being possible to obtain transitory
response from the body due to a variation in
environmental conditions. With this model, it
is possible to obtain heat and mass flow rates
to the environment due to radiation,
convection, evaporation and respiration. The
exergy balances provide the exergy variation
due to heat and mass exchange over the body,
and the exergy variation over time for each
compartments tissue and blood, the sum of
which leads to the total variation of the body.
Results indicate that exergy destroyed and
exergy efficiency decrease over lifespan and
the human body is more efficient and destroys
less exergy in lower relative humidity and
higher temperatures.
Among our most valuable resources is our
energy- physical, mental, emotional and
spiritual energy. Each of these is necessary for
optimal health and wellness. We know that
positive emotions can increase our energy and
negative emotions can drain our energy.
1.1.1 Exergy is a measure of energy
quality
Energy comes in many different forms, all of a
different inherent quality. ‘Quality’ can refer
to a number of attributes – ease of transport,
energy density, environmental impact, etc. –
but we refer here to its most fundamental form,
which encapsulates the ability to perform
physical work, i.e. to overcome a resistance to
make an object move. This is important when
considering thermal energy (heat), which is
intrinsically of a lower quality than other forms
of energy (such as electricity or mechanical
motion) (2). This is because for a given amount
of heat, a portion – depending upon its
temperature – will constitute the low-grade
waste heat which cannot then be recovered and
made to do physical work (for example, in a
heat engine).Exergy analysis is applied to
assess the quality of the energy conversion
processes that take place in the human body,
aiming at developing indicators of thermal
comfort based on the concepts of destroyed
exergy rate, exergy transfer rate to the
environment and exergy efficiency. In
literature only destroyed exergy has been used
to evaluate thermal sensation. To perform the
exergy balance, it is necessary to calculate the
exergy variation of the body over time which
is a composition of metabolic exergy and the
exergy
variation
due
to
transient
environmental conditions. The exergy transfer
to the environment is calculated as the sum of
the terms associated with radiation,
convection, evaporation and respiration. The
thermal behavior of the human body is
simulated by a model composed of 15
cylinders, naked and dressed for winter
seasons, as a function of the air temperature,
mean radiant temperature and relative
humidity. The energy equation is solved to
obtain transitory response of the body due to a
variation in environmental conditions and the
energy transfer to the environment. For
relative humidity between 40% and 60%,
results indicate that the destroyed exergy is
minimal for thermal comfort conditions.
Nevertheless, for low relative humidity and
high temperatures the destroyed exergy is also
minimal, indicating the necessity of another
physical quantity to evaluate thermal comfort
conditions. At this point the exergy transfer to
environment is high, showing that the body
may not be at thermal comfort condition. This
article proposes is to use two terms of the
exergy analysis to evaluate the thermal
comfort condition: destroyed exergy and
exergy transfer to environment.
2.
Material & Methods
Renewing our minds, transforming our
heart-sound fait
2.1
Emotional Renewals
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2.1.1
Reduce Denial and “Clean House”
Emotionally
Everyone has defenses. We learn to
cope with our emotional trials and issues by
developing coping strategies. Some are
positive, such as using relaxation, meditation,
exercise, or participating in an enjoyable
Denial is often difficult to recognize and
change, because it involves a tendency to
ignore or pretend that an issue does not
actually exist. -Rita Milios recreational
activity. Others are negative, such as worrying,
denying, or withdrawing. Denial is often
difficult to recognize and change, because it
involves a tendency to ignore or pretend that
an issue does not actually exist. Yet denial
costs us emotionally. It takes a lot of energy to
“keep the lid on” uncomfortable or unwelcome
emotions. But if we actively deal with such
issues, we not only enhance our lives
emotionally, we also recover vital energy that
can be used for other positive purposes in our
lives. (3)
Since denial is often maintained by
distraction (use of substances, overspending,
working excessively, etc.) and self-blame
(internalizing an issue and automatically
blaming one’s self without validating the need
for blame), it is important to look for “the truth
that can set you free” from distorted beliefs and
see reality for what it actually is, not what you
fear or worry that it is.
Old, self-defeating beliefs from the past often
direct our behavior, causing unwelcome
consequences, whether we overtly recognize it
or not. So, it behooves each of us to clear up
the negative beliefs about ourselves that may
be supporting our self-destructive behavior.
2.1.2
Write a Letter for Emotional
Release
One good way to dispel negative beliefs is to
write a letter to yourself, detailing exactly why
you feel emotions such as shame, guilt, worry,
etc. Try to get all the negative emotions out of
your body and mind, and transfer them to the
written page. Do not judge what you are
writing. When finished, set the pages aside for
a day or so. Then, when you are ready, read
them aloud. Consciously and logically
determine if you should make amends and
what these might be, taking into account how
any other persons affected may respond. (Do
not re-offend by tearing open old wounds. If
the others involved would feel more distress
than closure, simply ask forgiveness of them
mentally, and do not make actual contact.)
Then, once you have processed the emotions,
re-frame any negative beliefs about yourself
and tear up or burn the letter. Affirm that the
guilt, shame or worry has been released, and
make a conscious intention to act as if this has
occurred.
2.1.3
Be Aware of Your Feelings
Throughout the Day
Periodically, throughout the day, do an
“emotional check-in” to see how you are
feeling. Every hour or so, simply take a
moment to evaluate: are you happy, sad, angry,
frustrated, or feeling something else?
Once you determine what you are feeling, if it
is not a positive, helpful feeling, decide to
change it. Do this by first desiring and
intending to change your mood. Then visualize
something that will produce the desired mood
change in you. For instance, picture yourself
doing something that makes you happy and
proud of yourself. Then affirm, this is the
feeling that I am encouraging in my mind. If
you regularly “change the channel” of your
mental and emotional state, you will create a
habit of this mental and emotional re-adjusting
process. Then your positive mood will be more
likely to maintain itself without regular
monitoring.
If you regularly ‘change the channel’ of your
mental and emotional state, you will create a
habit of this mental and emotional re-adjusting
process. -Rita Milios (3)
2.2
Spiritual Renewals
2.2.1 Connect with Nature
Many of us find nature to be very renewing to
our mind and spirit. Ironically, our busy lives
often keep us from utilizing this valuable–and
free–resource. But by making a conscious
commitment, you can increase your exposure
to the natural world and experience the
recovery and renewal that being in nature
provides. Simply taking a walk outdoors and
noticing the environment – trees, water, sun,
wind – brings your attention out of your own
head, allowing you to relax mentally, and
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instead, note what you are experiencing from a
higher, spiritual level.
If you have access to a lake or ocean view,
spending some time just watching waves roll
in is very relaxing and renewing for most
people. Even if you do not have this option
available, you can listen to the sounds of waves
via a sound machine or CD. Today, there are
even some television programs that offer
meditative music and visuals for relaxation and
renewal.
2.2.2 Read Spiritual Literature
Reading some inspirational or spiritual
literature daily is a great form of spiritual
practice. With such reading, you can
temporarily remove yourself from the day’s
pressures, concerns and challenges and allow
your mind and body to rejoin with your higher
spiritual nature. Even a few minutes of this
kind of transcendent experience can dispel
negativity from your mind and emotions and
allow you to feel rejuvenated and re-energized
on all levels.
‘Let me today respond to each person I meet
with kind words, appreciation and patience.’Rita Milios
You might also consider ways to bring this
positive feeling into the rest of your day. One
such option is to reflect on something that you
are grateful for or something that you would
like to set as an intention for the day. For
example, you might affirm: “Let me today
respond to each person I meet with kind words,
appreciation and patience.” (4)
2.2.3 Attend a Spiritual Group Activity
Being with others when we are involved in a
spiritual activity often enhances the
experience. For many people, attending church
or a support group is uplifting and enjoyable.
With like-minded people to share your
spiritual experience with, you are also more
likely to stay committed to a regular practice
and therefore gain more of the positive
benefits. It is worth taking the time to visit as
many gatherings as necessary in order to find
the group that fits you best. Finding a spiritual
“home” can be one of the best things you do to
renew and re-energize yourself.
2.3
Renewable Energy: How to Renew
Your Physical and Mental Energy
Energy a little low? Like many people, you
may be experiencing a bit of seasonal letdown.
Now that the excitement of the holidays has
died down, January and February seem to loom
ahead with nothing to offer but short, cold and
often dreary days. The transition from a hectic
but fun schedule to your regular, everyday
routine can seem boring and somewhat
depressing at first. Not only that, like many
others, you may have expended so much
energy over the past couple of months that you
need rejuvenating – not only in body, but in
mind, emotion and spirit as well.
Fortunately, there are ways to do just that. This
two-part article shares some rejuvenation and
renewal techniques for all aspects of your
being. So, take the next few weeks to explore,
experiment and experience new ways to
promote within yourself a more vibrant,
energetic and renewed state.
2.3
Physical Renewals
2.4.1 Exercise
It’s not a coincidence that many people embark
on an exercise regime in January. Not only do
many of us need to shed a few pounds that we
gained by celebrating a bit too heartily, we also
recognize that exercise, both literally and
figuratively, can get you going. A 2008 study
from the journal Psychotherapy and
Psychosomatic (4) found that study
participants achieved increases of energy of
approximately 20 percent and decreases in
feelings of fatigue of up to 65 percent, simply
by participating in regular, low-intensity
exercise.
But calm energy, which combines high mental
energy with low physical tension (such as
Pilates, TaiChi, walking…), allows the body to
avoid fatigue and actually increases your
energy level. -Rita Milios(3)
But not all exercise is created equal. According
to Robert E Thayer, Ph.D., author of Calm
Energy: How People Regulate Mood with
Food (2001, Oxford University Press, NY) (5),
there are actually two different types of
energy–what he calls “tense energy” and “calm
energy”–and they each have different effects
on the body. Thayer says many of us typically
utilize tense energy, working or exercising our
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bodies at a high, intense physical level, like
when we work out at the gym. This kind of
energy expenditure often makes you feel tired
afterwards. But calm energy, which combines
high mental energy with low physical tension
(such as Pilates, TaiChi, walking and strengthtraining, if movements are done slowly and
deliberately) (6), allows the body to avoid
fatigue and actually increases your energy
level.
2.4.2
Proper Sleep
Deep sleep, which happens in cycles about
every 90 minutes throughout the night, is
crucial for physical renewal, hormonal
regulation, and growth. Without deep sleep,
we are more likely to get sick, feel depressed,
and gain weight. But according to the National
Sleep Foundation, only about 28 percent of us
get enough sleep each night. We need 3 to 4
deep sleep cycles (about 7 to 8 hours of sleep)
to allow our bodies to renew and repair
themselves. Sleeping in a cool, dark room
enhances the sleep experience, and allows for
the most restorative sleep, experts say.
2.4.3
Deep Breathing
One reason you may be feeling low on energy
is that your cells may be starving for oxygen.
Too many of us have gotten into the habit of
breathing shallowly, which prevents air and
oxygen from fully penetrating the lowest
portions of our lungs. This kind of breathing
can suck your energy and make you feel
anxious, says Pam Grout, the Alternative &
Complementary Medicine correspondent at the
Dr. Oz health website.
To help you breathe better, practice taking full
diaphragmatic breaths for several minutes a
few times a day. The Harvard Mental Health
Letter offers these suggestions: You’ll notice
that shallow breathing often feels tense and
constricted, while deep breathing encourages
relaxation. -Harvard Mental Health Letter (7)
Start by observing your breath. First take a
normal breath. Then take a slow, deep breath.
The air coming in through your nose should
move downward into your lower belly. Let
your abdomen expand fully. Now breathe out
through your mouth (or your nose, if that feels
more natural). Alternate normal and deep
breaths several times. Pay attention to how you
feel when you inhale and exhale normally and
when you breathe deeply. You’ll notice that
shallow breathing often feels tense and
constricted, while deep breathing encourages
relaxation.
2.5. Mental Renewals
2.5.1 Meditation: Give Your Left-Brain a
Break
Most of us are left-brain heavy. We use our
thinking, processing left-brain more than our
creative, intuitive right-brain. You can refresh
and renew your whole mind by giving your
left-brain some down time. Meditation slows
brain waves and “re-sets” your brain,
increasing mental clarity and improving your
problem-solving ability while relaxing you.
An easy way to meditate is to simply notice
your breath and put your full attention there,
noticing how it feels for your lungs to expand
and your diaphragm to recoil. You can also
repeat a word or mantra, such as “peace” or
“relax” with each breath. Even a short 5 to 10minute meditation, practiced regularly, can
provide significant benefits.
2.5.2 Balance Your Brain
You can achieve even more left-right brain
balance and mental renewal by doing a brain
balancing exercise: Close your eyes and
visualize your brain inside your head. Picture
the left and right sides, with the corpus
callosum, or centerline, between. Imagine that
each side is filled with an energy-filled fluid,
and that on the left side the fluid level is higher
than on the right. Imagine “poking holes” in
the corpus callosum that separates the two
sides of your brain, so that the energy-fluid can
flow from the left side to the right side, until
the two sides are leveled out. Affirm to
yourself, “My brain’s energy is now balanced
and I am centered.”
2.5.3 Power Nap
Do you regularly nap for 10 to 30 minutes
between the hours of 1 p.m. and 4 p.m. most
days? If so, you are a “power napper” and
according to Sara Mednick, researcher and
author of Take a Nap! Change Your Life
(Workman Publishing; 2006), you are boosting
your alertness and possibly improving your
memory as well. Apparently, the publishers of
Mednick’s book were so impressed with her
research regarding the benefits of power
napping that they created “napping rooms” so
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that their employees could refresh themselves
during the work day. More companies are also
approving power napping for their employees,
and seeing improvements in their productivity
as a result.
2.6 How to Manage and Revitalize Your
Personal Energy
2.6.1
Energy, Health, and Conscious
Living
One of the major health issues affecting people
today is lack of energy. The energy crisis we
are currently facing is not limited to our
environment and the planet we live on. The
crisis extends to each one of us, and the bodies
we live in. More and more people suffer from
stress related illnesses. In fact, research
suggests that as many as 80-85% of all disease
and illness is caused by stress.1
The technological age that promised extended
free time and increased leisure is draining us
energetically. Work pressures, relationship
issues, parenting, financial worries and fears
for the future, all drain energy and create
stress. Stress leaves us feeling tired, wound up
and low in energy. In our fast paced, I need it
yesterday world the only constant is change.
And when everything changes we must adopt
new coping mechanisms. How we manage
personal energy is the new key to creating a
high quality of life.
2.6.2 Managing Personal Energy
Most of us want enough energy and vitality to
live life to the fullest. We don’t want to feel
drained, exhausted and stressed out all the
time. And why should we when being full of
energy is our birthright. Energy is the fuel
humans are designed to function on. We need
regularly topped up, good quality energy for
optimum health and wellbeing.
Everyone is familiar with energy and describes
it in different ways. How many times have you
said or heard others say ‘I feel full of energy’
or ‘I am low on energy’? You may have heard
people speak of ‘having no energy left at all’?
(8)We speak of liking and disliking someone’s
energy or vibration. Energy is very much part
of our experience and common language. [
AMA Business Week 2003]
2.6.3 How One’s Energy Gets Drained
Energy has been the focus of my work for over
the last twenty-five years. As a Health and
Success Coach I have had the privilege of
working with thousands of people all over the
world. From my experience I have observed
five main ways people allow their personal
energy resources to get drained.
1. Overwork is the number one energy
zapper. The culture of working long hours in
the office or working from home without
clear boundaries causes tiredness, poor
concentration and eventually leads to
exhaustion.
2. Reluctance to exercise takes the
number two spot. We all know the benefits of
exercise yet travelling by car and sitting down
all day creates insufficient movement, which is
a major energy zapper and cause of stress.
3. Poor diet is another issue, with people
eating foods lacking in vitality and nutritional
value. Eating on the move and yo-yo dieting
prevent nutrients being adequately absorbed.
We need to consume foods that provide energy
and sustain life. Most of us know the theory of
what to eat, yet still fall prey to all manner of
poor eating habits.
4.
Constant worrying is another way
energy gets depleted. People often entertain
fears and play out dramas, in the mind, that
never happen in real life. Not to mention carry
the weight of the world on their shoulders. Can
you imagine how much energy that takes?
5.
And on top of all that there never
seems to be enough me-time to refuel. Think
about it, even cars get an oil change and a
regular service. No one expects a vehicle to
run on empty and I am sure you always give
your car the best fuel you can afford.
So how about your body? Surely you deserve
the best. What is the key to good health,
optimum function and living life to the full?
3.
Conclusion
3.1 Energy is the Fundamental Building
Block of Life
We have seen that energy is the fundamental
building block of life. We know that modern
living encourages the use and abuse of our
personal energy resources. What then is the
way forward?
My research over twenty-five years has
involved the study of energy, holistic
healthcare, psychology, spirituality and new
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paradigm medicine. I traveled worldwide and
experienced how people maintain health and
achieve success in different cultures. This led
me to develop a powerful energy-based
approach to balanced living. I literally took the
most potent, quick acting, easy to use
techniques for energy management and created
a new approach to health and conscious living.
Having uncovered the five main energy
zappers, I looked at ways energy could be
restored and revitalized. I knew from my work
in holistic health care that there is absolutely
no need to wait to get ill before making life
changes that positively impact your health and
wellbeing. Therefore, we explore four main
ingredients that are guaranteed to get energy
flowing and not only to restore energy levels
but also to prevent illness; creating healthy,
happy and successful lives in the midst of a
changing world.
The four main ingredients are:
Energy Exercises to re-energize your body
Energy Psychology to release stress
and free your mind
Energy Foods that re-vitalize your system
Energy Balance to relax and calm you
Creating abundant energy is not as difficult as
it seems. The magic of this formula is that it
can be used to revitalize energy anytime and
anywhere. A few minutes every day can make
an enormous difference to your energy levels
and quality of life.
3.2
How to Revitalize Your Personal
Energy
I strongly believe in the dictum, less is more.
Don’t sweat the small stuff and Pareto’s 80-20
law definitely works for me. The Italian
economist Pareto said that 20% of your energy
creates 80% of your results. That means most
of what you do creates very little. For example,
20% of your wardrobe accounts for 80% of
what you wear. 20% of the world’s population
uses 80% of its resources. Does that make
sense? It’s all about learning to master energy.
So don’t underestimate the power and
simplicity of the following exercises. The
secret of this lies in the simple things you can
add into your day to create maximum impact.
Didn’t Duke Ellington once say, “I merely
took the energy it takes to pout and wrote some
blues”.(9) That is energy mastery and the
simple exercises below can help you achieve
it.
3.2.1 Breathe and Relax.
For just two minutes stop what you are doing,
slow down and be completely mindful of your
breath. This re-oxygenates, rejuvenates and
relaxes your body-mind, which in turn creates
calm and greater clarity. If you doubt two
minutes can make a difference, try it.
Regularly incorporate mini vacations into your
day. I recommend two minutes in every hour.
3.2.2 Get out of your head and into your
body.
Especially if you usually sit at a desk all day.
Take a moment to stretch with awareness.
Rotate your neck, arms and shoulders to
release any tightness. Walk upstairs, stretch
your ankles and feet to improve circulation,
release blockages and elevate energy.
3.2.3 Inner smile
Great for releasing negative energy. Close
your eyes and visualize your lungs smiling,
then see your heart smiling and your liver, your
intestines and all your internal organs one after
another. This is hard to do without bringing a
smile to your face and releasing negativity.
Negative emotions create disease, so let go of
any stored negativity and give yourself a big
inner smile.
3.2.4 Make use of nature’s perfect health
drink H2O.
There is no better way to lift energy than by
drinking water. Fatigue, headaches, digestive
problems and low energy levels are often
removed simply by drinking more water. 75%
of the population are dehydrated. So next time
you feel low, reach for the H2O.
The energy crisis we are experiencing can be
alleviated with more awareness of how we go
through each day. It’s important to remember
that the flow of energy in the human body,
mind and spirit is the foundation of health and
success.
Human power used to be all the rage. 150 years
ago, products that relied on human energy such
as the bicycle, pedal-powered lathe or sewing
machine could be found in most households.
But as electro-mechanical motors developed,
reliance
on human-powered products
gradually diminished.
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Today, human power is not appropriately
recognized for its potential as an alternative
solution to our growing energy needs. Indeed,
as we search for more renewable energy
sources, is it possible to abandon using
traditional electricity for certain tasks and
return to human power? The way that more and
more products are becoming digital and even
internet-connected makes this a challenge. But
humans emit energy that can easily be
harnessed from our everyday behavior.
The bicycle is a great way of using human
power in a way that allows us to exercise,
transport ourselves and save on the
consumption of conventional energy at same
time. If, for example, we can design bicycles
to become more entertaining for people to use,
they could encourage more people to adopt
human power in this way. For example,
London-based company Electric Pedals is
using the pedal-powered technology to
generate electricity for events such as outdoor
cinemas, educational workshops and music
stages.
Human-powered products also have the
potential to encourage us to become more
physically active. According to the British
Heart Foundation, around 32% of adults spend
six hours a day during the week being
sedentary, which means too much sitting and
not enough exercise. According to my
calculations, if these individuals spent half of
their sedentary time exercising on a pedalpowered television, approximately £49 million
worth of electricity could be generated per
year, with a lot of calories burned on top.
Using human-powered products as a
countermeasure to our increasingly sedentary
lifestyles could create a credible new
perspective towards exercise as an alternative
energy source. In some respects, human-power
can be seen as the cleanest renewable energy
source available, with great potential for
helping people stay healthy and have fun.
The human body contains enormous quantities
of energy. In fact, the average adult has as
much energy stored in fat as a one-ton battery.
That energy fuels our everyday activities, but
what if those actions could in turn run the
electronic devices we rely on? Today,
innovators around the world are banking on
our potential to do just that.
Movement produces kinetic energy, which can
be converted into power. In the past, devices
that turned human kinetic energy into
electricity, such as hand-cranked radios,
computers and flashlights, involved a person's
full participation. But a growing field is
tapping into our energy without our even
noticing it.
References
1. Ibrahim Dincer, Marc A. Rosen, “Exergy:
Energy, Environment and Sustainable
Development” 2nd edition Elsevier
2. SciIll Staff , “Credit: Adam Boesel”
January 29, 2009.
3. Rita Milios, ”Health and Wellness, Living
in Recovery, Living with Addiction”
January 2, 2015
4. Stephen R. Covey, “7- Habits of Highly
Effective People”, Free Press, 1988
5. Robert E Thayer, Ph.D., “Calm Energy:
How People Regulate Mood with Food”.
2001, Oxford University Press, NY,
6. Tony Schwartz, Catherine McCarthy
Manage “Your Energy, Not Your Time”
7. “A spiritual and physical renewal Review
of The Empower Yourself Project”,
https://www.tripadvisor.in/ShowUserRev
iews-g309253-d7307148-r361558185The_ Empower_ Yourself_ ProjectTamarindo_Province_of_Guanacaste.htm
l, retrieved on December 08, 2017
8. Kathleen Barton, Renewal for Your
Mind, Body and Spirit, Tuesday, 15 May
2012 19:21
9. Daniel
Henderson,
“Emotional
Equilibrium” Reviewed 4 April 2016,
10. Rita Milios,
“Health and Wellness,
Recoveries” December 29, 2014
11. AMA Business Week 2003
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Renewable Energy Management for Smart Cities of India
Daljeet Singh, Surya Prakash Meena
Department of Mechanical Engineering,
Govt. Engineering collage, Banswara
2015pie5168@mnit.ac.in, suryaprakashmn@gmail.com
Abstract:
In the previous couple of years numerous ground-breaking promises have been made about the
prospective of the Smart City. A smart city is a sensible and resourceful urban center that gives a
high value of life to its population through most favourable organization of its resources. Electricity
management is one of the most traumatic problems within such urban centres attributable to the
complexity of the energy systems and their critical function. The potential of cities is predicated
perceivably on improved electricity environment and provides reliable24X7 electricity to
consumers. In the last years India has actively promoted the smart grid, renewable energies for
residential and tertiary buildings and focus should be on green buildings and green transport to
reduce the need for electricity.
This paper investigates the term of smart city, classified Renewable energy source for smart city of
India. The benefit of application of Renewable energy management is that it will lessen entire cost
of electricity, develop sustainability, and increase customer fulfillment.
Key Word: Smart city, Renewable Energy.
1.
INTRODUCTON
The current trend in our utilization of the
earth’s resources is unsustainable and is making
major surroundings issues. Temperature change
resource depletion, loss of diversity, and
pollution has a serious impact on many voters
and therefore the earth, and that we ought to
modification our current behaviour. Our gift use
of the earth’s finite resources cannot be
maintained. We want to makeover to property
development, that ’meets the requirements of
this while not compromising the power of
future generations to satisfy their own needs
[1].
The environmental burden could be operating
of population, wealth, and technology and
dominant the primary two factors are very
difficult. The larger the population, the lot of
impact it's upon the planet. Additionally, the
overwhelming majority of individuals aim to
affluent lifestyles, and wealthier folks consume
way more resources than less affluent folks.
Technology is each an explanation for the
environmental burden and additionally a
possible resolution. Technology like coal-fired
power stations provides the electricity we want
to support Associate in nursing affluent fashion,
however at constant time it creates carbon
emissions that contribute to heating. instead,
renewable energy technologies supported wind
and solar, as an example, square measure
doable solutions for property, although every
has negative consequences in addition (e.g., the
energy and materials needed to construct wind
turbines or solar panels) [2].
A Smart town is associate in nursing urban
Development to enhance the standard of life
exploitation varied varieties of technologies and
to enhance the potency of services. Smart town
applications square measure developed with the
goal of up the management of urban flows and
letting real time responses to challenges. The
Smart city's assets embrace native department’s
data systems, schools, libraries, transportation
systems, hospitals. For creating a town sensible,
Renewable Energy is best to use in cities [3].
Renewable energy plays a very important role
within the long-run energy provides security,
diversification of energy combines, energy
access, environmental security and property.
Renewable energy is absolute to play Associate
in nursing increasing role in future energy
systems.
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2.LITERATURE :
A lot of existing literature review articles is
accessible on the standalone ways that of
Renewable energy and sensible town; still some
endeavours are created by the researchers
within the past to rearrange and recreate the
present state of affairs of Renewable energy in
smart city.
Joshi, S. and Joshi, F. (2016) appearance at
problems, challenges for alternative energy
plants and solutions to beat challenges. The
solar smart cities will be with efficiency
developed with utilization of solar power.
ample solar radiation is obtainable in states like
Rajasthan, Gujarat, Maharashtra, Tamilnadu
and few others states as mentioned higher than.
solar systems put in on rooftops of residential,
commercial, institutional & industrial
buildings premises will solve the energy crisis
also will become a supply of financial gain
because it will be -fed into the grid at regulated
feed-in tariffs or -used for self-consumption
with
net-metering
approach.
Optimum
utilization of solar power is going to be welltried to be a boon to the society by its
sustainable development. India will become a
developed nation by creating sensible cities and
sensible villages.
Calvillo et al. (2016) this paper has two main
objectives. The primary is to develop in view in
to the quality of the energy-related activities
during a smart-city context by reviewing
advances and trends and by analyzing the
synergies among totally different intervention
areas. Moreover, a number of them typical
applications commencement the literature for
the assorted energy areas, also as operation and
designing tools area unit reviewed.
The second objective is to help stakeholders
and policy manufacturers in the design of
energy solutions for smart cities by providing
ways for the effective modelling and
management of energy systems and by
reviewing existing comes and computer code
tools. These ways embody the foremost
relevant parts and customary sources of data
needed for his or her mathematical modelling.
Albino et al. (2015) this paper makes an
attempt to clarify the means of a plan that's
obtaining progressively popular—that of the
smart town. Associate degree in-depth analysis
of the literature disclosed that the means of a
smart town is multi-faceted. Descriptions of
smart cities are currently as well as qualities of
individuals and communities also as ICTs.
Several parts and dimensions characterizing a
smart town emerged from the analysis of the
present literature. Results show however
difficult the measure of a wise town is. Some
attempts to form blanket indexes are reviewed.
However, this paper wasn't meant to outline a
brand new framework for the assessment of the
smartness of a town, since the authors believe
that such associate degree assessment ought to
be tailored to a selected city’s vision. A
universal fastened system is also tough to
outline with the variability of characteristics of
cities worldwide. However, it's been created
clear that the definitions exhibit by explicit
cities occupation themselves “smart cities” lack
catholicity.
Brenna et al. (2012) looks at Challenges in
Energy Systems for the Smart- Cities of the
long run. The study reportable during this paper
takes place in accordance with the European
policy and national ways for environmental
property and energy security, per the Horizon
2020 objectives that include:
promoting distributed generation systems;
promoting cogeneration (combined heat and
power systems, CHP) additionally for
residential,
tertiary
and
commercial
buildings;
the preparation of property quality through
the employment of electrical vehicles;
Promoting the rational use of electricity
through actions geared toward edge energy
expenditure and therefore the development
of near-zero energy buildings. to the current
purpose, several analysis studies area unit
geared toward learning intelligent network
(smart grid), that will enhance the
management of the distribution network.
Sinha et al. (2011)This paper discusses
concerning the smart grid initiatives in India,
implementation methodology, challenges and
edges. The paper discusses the requirement for
smart grid technology to attenuate the AT
& C losses that could be a burning issue
across all power distribution utilities in India.
The authors have highlighted some aspects of
varied key areas connected on smart grid
initiative for Indian Power distribution utility
like AMI, GIS, CRM, EAM, DMS etc.
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Additionally, elaborates the methodology to
implement the smart grid project in Indian
power situation.
Morvaj et al. (2011) this paper aim was to
develop a system that is operable for additional
development towards as well as alternative
.
3.
RENAWBLE ENERGY IN SMART CITIES
OF INDIA
The Ministry of new and Renewable Energy
later has Collaborated with the Ministry of
Urban Development in providing renewable
energy from sources like daylight, wind and
electricity for the good city’s electrical grid. a
complete of 37288 MW of power were with
success made for the smart cities, out of that
4345 MW of power were made from solar
power, 4419 MW of power made from biomass
and 24377 MW of power made from Wind
Energy. The Ministry of latest and renewable
energy aims to supply a complete of one
hundred seventy-five GW of electrical
power,100 GW from solar,60 GW from Wind
energy,10 GW from electricity plants, and five
GW from Biomass. As for the solar energy, The
MNRE aims to supply twenty GW from solar
Parks, ten GW from jobless Youth/Farmers,
thirty GW from Govt./Private corporations like
4.
CONCEPT AND DEFINATIONS
A. smart city:
We outline a smart city as a town that
frequently will increase its performance in
satisfying all desires of its citizens. This is
aligned with definitions in literature, wherever a
smart city may be a town that mixes ICT with
its physical infrastructure to enhance
conveniences,
facilitate
quality,
add
efficiencies, conserve energy, improve the
standard of air and water, establish any issues
within the operation of town systems and fix
them quickly, recover apace from disasters,
collect knowledge to form higher choices and
deploy resources effectively and expeditiously.
It can't be viewed as a add of components
however holistically as a network of
interconnected infrastructures obsessed on one
another.
It
usually
debated
whose
infrastructures and systems are those that create
the core of the smart town however typically
they're often narrowed all the way down to the
following:
important infrastructures and ultimately a
bigger scale between totally different systems
very important to a wise town. At this stage
electricity was investigated through a little scale
smart grid consisting of five smart buildings.
Essel, Sun-Edison, Lamp; T, etc., and forty GW
from solar rooftop. The Honourable Prime
Minister Shri Narendra Modi’s vision of
creating a hundred smart cities were with stress
to good Energy which has Renewable energy
generation, smart grid and guaranteed
electricity
provide,
and
sustainable
development.
The good Cities pointers insist that 100% of
the full electricity be made from solar power.
Therefore, MNRE has set to supply electricity
from solar power in homes and offices by
victimization solar panels within the top side,
Solar water heaters for warm water, solar PV
top side for electricity, solar Street Lighting,
solar Pumps for water lifting, solar
concentrators for steam primarily based change
of state and solar traffic signals. The MNRE
additionally needs to market energy economical
buildings on solar passive style.
1. Citizens,
2. Water and energy.
3. Communication,
4. Business,
5. Transport,
6. Town services,
B. Smart grid:
Incorporation of the smart grid technology
within the smart cities project can supply a
novel chance to leap into associate improved
electricity setting and supply reliable
24X7electricity to customers. Through smart
grids it'll be doable to integrate the coal and
fossil fuel generated electricity with the solar
and wind. this can cut back fuel use and
encourage worth drops in renewable
technology. Further, current smart grids also are
building the technology to integrate consumerowned energy systems which is able to profit
customers any – they're going to not have to be
compelled to get the electricity generated by
themselves. The sensible grid (Refer Fig1)
delivers electricity to shopper’s exploitation
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two-way digital technology to alter the
for growth of its high technical school and
additional
economical
management
of
telecommunications sectors.
consumers’ finish uses of electricity still
because the additional economical use of the
C. Smart meter
grid to spot and proper provide demandTraditional
meters
will
solely
offer
imbalances in a flash and observe faults in an
unidirectional info and should be browse in the
exceedingly “self-healing” method that
flesh by a meter reader. Smart meters are digital
improves
service
quality,
enhances
meters that provide two-way communication
responsibility, and reduces prices. The rising
permitting additional interactivity between the
vision of the smart grid encompasses a broad
patron and utility. a smart meter are often water,
set of applications, as well as computer code,
gas, electricity and warmth meter. During this
hardware, and technologies that alter utilities to
paper it refers to a smart electricity meter.
integrate, interface with, and showing Characteristics of a smart meter are:
intelligence management innovations.
Close to or period activity of a consumption of
Key objective of smart Grid
the Electricity usage and also the quantity of the
Self-healing: The grid apace detects,
electricity Generated locally;
analyzes, Responds, and restores
Are often browsing each remotely and locally;
Empowers and incorporates the client: Utilities may use the sensible meter limit the
Ability to include consumer instrumentation
number of electricity progressing to or from the
and behaviour in grid style and operation
sensible building or even utterly disconnect the
Tolerant of attack: The grid mitigates and is
customer.
resilient to physical/cyber-attacks
The smart meter acts sort of a entry for the
smart building to speak with the remainder of
Provides power quality required by 21stthe grid. GSM, Broadband over transmission
century users: The grid provides quality
line (BPL), WiMAX, net and alternative
power per shopper and business desires
wireless communication standards are often
Accommodates a good style of provide and
used as a customary for the communication.
demand: The grid accommodates a spread of
This communication is bidirectional. Utilities
resources, as well as demand response,
will browse the meters remotely in real time
combined
heat
and
power,
wind,
and that they will send worth signals to the tip
photovoltaic’s, and end-use potency
customers. Customers have an summary of their
Totally permits and is supported by
consumption and worth of the electricity in real
competitive electricity markets.
time. By that approach customers will reply to
Need for smart Grid in India:
the occurrences within the grid that is that the
With such monumental deficiencies in basic
idea of the demand response.
infrastructure, why would India| need to think
D. Smart Building
about investment in smart grid technologies?
The term smart buildings are used for over a
Ultimately for India to continue on its path of
twenty year to introduce the idea of networking
aggressive economic process, it has to build a
devices and instrumentation within the building,
contemporary, intelligent grid. it's solely with a
and energy potency. In last half of Seventies, it
reliable, financially secure sensible Grid that
had been a building that was designed
India will offer a stable setting for investments
employing a idea of energy potency and in
in electrical infrastructure, a necessity to fixing
Eighties it had been a building that would be
the basic issues with the grid. While not this,
controlled from a house computer. Today, smart
India won't be able to keep step with the
buildings use the Seventies and Eighties idea
growing electricity desires of its cornerstone
with extra subsystems for managing and
industries, and can fail to form associate setting
dominant renewable energy sources, house
appliances and energy consumption exploitation
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most frequently a wireless communication
technology. ICT permits sensible buildings to
speak each with its within devices and
appliances,
that
they'll
additionally
management, and with its surroundings. What is
more, they'll adapt to grid’s conditions and
communicate with alternative buildings,
therefore making active small grids or virtual
power plants.
Sensors - watching and submitting messages
just in case of changes;
Actuators - playing a physical action;
Controllers – dominant units and devices
supported programmed rules set by user;
Central unit – enabling programming of
units within the system;
Interface - the user communication with the
system;
Network - permits communication between
the units
Smart meter - offers two-way, close to or
period communication between client and
utility company
Sensors, actuators, controllers, central unit,
interface with network customary create a
building automation. The smart energy building
has additionally to mentioned elements
additionally energy storage and little renewable
energy supply.
5.
CONCLUSION
Smart town construct may be used for
reworking any town into a sensible town. Smart
town have numerous overwhelming advantages
& it a win – win scenario for each,
government & the citizens. So as to realize
best energy management in a very complicated
system sort of a good town, not solely do most
of its energy components have to be compelled
to be known and studied, however the implicit
relations among them even have to be thoughtabout. Supported this study, some clear trend
scan be known altogether intervention areas,
taking advantage of advance sin technologies
and reduced costs.
References
[1]. Naphade, M., Banavar, G., Harrison, C.,
Paraszczak, J., & Morris, R. (2011). Smarter
cities
and
their
innovation
challenges. Computer, 44(6), 32-39.
[2]. Mathiesen, B. V., Lund, H., Connolly, D.,
Wenzel, H., Østergaard, P. A., Möller, B., ... &
Hvelplund, F. K. (2015). Smart Energy
Systems for coherent 100% renewable energy
and transport solutions. Applied Energy, 145,
139-154.
[3]. Lombardi, P., Giordano, S., Farouh, H., &
Yousef, W. (2012). Modelling the smart city
performance. Innovation:
The
European
Journal of Social Science Research, 25(2),
137-149.
[4]. Joshi, S. B., & Joshi, F. M. Role of Solar
Energy Applications in Developing Smart
Cities of India. Proceedings of national
conferencece on Recent Advances in Computer
Science and Technology (RACST-16), Oct, 16.
[5]. Calvillo, C. F., Sánchez-Miralles, A., & Villar,
J. (2016). Energy management and planning in
smart cities. Renewable and Sustainable
Energy Reviews, 55, 273-287.
[6]. Albino, V., Berardi, U., & Dangelico, R. M.
(2015). Smart cities: Definitions, dimensions,
performance, and initiatives. Journal of Urban
Technology, 22(1), 3-21.
[7]. Brenna, M., M. C. Falvo, F. Foiadelli, L.
Martirano, F. Massaro, D. Poli, and A.
Vaccaro. "Challenges in energy systems for the
smart-cities of the future." In Energy
Conference and Exhibition (ENERGYCON),
2012 IEEE International, pp. 755-762. IEEE,
2012.
[8]. Sinha, A., Neogi, S., Lahiri, R. N., Chowdhury,
S., Chowdhury, S. P., & Chakraborty, N.
(2011, July). Smart grid initiative for power
distribution utility in India. In Power and
Energy Society General Meeting, 2011
IEEE (pp. 1-8). IEEE.
[9]. Morvaj, B., Lugaric, L., & Krajcar, S. (2011,
July). Demonstrating smart buildings and smart
grid features in a smart energy city.
In Energetics (IYCE), Proceedings of the 2011
3rd International Youth Conference on (pp. 18).
IEEE
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Design Aspects of Small Scale Wind Turbines: A Review
Ankush Jain, K. B. Rana, B. Tripathi
Department of Mechanical Engineering, Rajasthan Technical University, Kota-324010, India
Corresponding Author E-mail: ankushjain03@gmail.com
Abstract
The limited nature of fossil fuels is an important incentive for global transition towards renewable
energies. One of the viable sustainable energy sources is wind. The large-scale wind farms are not a
good option due to their undesirable effects on environment; hence installation of small scale wind
turbines (decentralized grid system) is a sustainable option. This paper presents review on design of
different types (i.e., horizontal axis and vertical axis) of small scale wind turbines. The blade design,
control, aerofoil and aero-acoustic aspects of small scale wind turbines were reviewed.
Keywords: Small scale wind turbines, Blade design, Aeroacoustics, Aerofoil
1.
Introduction:
Nowadays the world is facing problem due to
energy crises, energy production rate is lagging
the energy demand. The power generation is
mainly dependent on fossil fuels, which is
nevertheless having its negative impact on
climate. Renewable energy is one of
alternative options for eliminating fossil fuelbased power production. Wind energy is a
promising technology which can contribute to
reduce of carbon credit and reducing the
polluting factors accumulated due to use of
fossil fuels. In wind turbines the kinetic energy
of wind is used to develop rotational power
over the shaft. According to world wind energy
association, the worldwide wind energy
capacity extended to 486661 MW by the year
of 2016, out of which 54846 MW were
installed in 2016. This represents the growth
rate of 11.8 % whereas in 2015 it was 17.2%.
Approx 5% of total world electricity demand is
full filled by the wind power. Latin America
and China has increased their share of new
wind power project installations to 6.5 % and
5.3 % respectively.
The general technique in the field of wind
energy harnessing is the use of unitary big
capacity utility scale wind turbine. The utility
scale wind turbines are deployed to supply
power to large number of consumers by a
single unit. The utility scale wind turbine is a
centralized large sized wind turbine which
requires a huge amount of financial investment
and organizational set up. In contrast regarding
the case of utility scale wind turbines some
researchers have found the negative outcomes
over climate.
Wang et al. (2010) found by his exhaustive
review that deploying large scale wind turbine
to get 15-25% power demand of world it can
lead to increment of 10C of ambient
temperature. Similarly, Fiedler et-al (2011) did
a survey for 62 warm seasons, on a particular
climatic model and found that it can lead to 1%
increase in precipitation rate and occurrence of
larger precipitation for the places where large
scale wind farms exist. Small scale wind
turbines which are with capacity ranges of 1
kW or even less have their own advantages.
The chief advantages are; small scale wind
turbine can be brought and set up by an
individual with a small monetary investment
and no organizational set up is required. Small
scale wind turbine can be implanted over the
roof top of building and the supervision
required for that purpose is not of that much
degree as compared to utility scale wind
turbine.
In 2015, a cumulative total of at least 990000
small wind turbines were installed all over the
world. This is an increase of 5% compared
with the previous year, when 945000 units
were registered. It means that worldwide
several million families are getting power from
small scale wind turbine. However only in
Italy the number of new installations increased
during 2015. The recorded small-scale wind
capacity installed worldwide has reached more
than 945 MW as of the end of 2015. This is a
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growth of 14 % compared with 2014, when
830 MW were registered. According to World
wind energy association, China accounts for 43
%, the USA for 25 %, UK for 15 %, and Italy
for 6.3% of the global capacity.
Small scale wind turbines are gaining their
importance around the globe. In July 2012, a
new kind of feed-in tariff was approved by
Japan in order to boost the country's production
of wind and solar energy production. Small
scale wind power turbines soon will be
subsidized at least 57.75 JPY (about 0.74 USD
/kWh). In UK, the people in rural or suburban
parts of the UK can select for a wind turbine
accompanied with an inverter to supplement
local grid power. The UK's Micro-Generation
Certification Scheme (MCS) has a provision of
feed-in tariffs to owners of qualified small
wind turbines. The owners can now install a
micro renewable energy system and shall be
getting paid for that (Bahaj et al., 2006).
Small scale wind turbines are also handy in
some autonomous applications which require a
very high level of reliability. Some units are
designed very light weight in their structure,
e.g. 16 kilograms, allowing sensitiveness to
minor wind motions and a rapid response to
wind squalls typically found in urban settings.
Some are easily mountable such like a
television antenna. These wind turbines can be
used as are liable source of energy when they
are sized properly and are used at their
optimum conditions. This paper presents a
literature review on general classification and
design aspects (blade design, control, aerofoil
and aero-acoustic) of small scale wind
turbines.
2. Small Scale Wind Turbines:
There is no fix threshold limit in regards of any
feature of wind turbine to separate the utility
scale wind turbine from a small-scale wind
turbine. However, the small wind turbines
rotor is usually of 1.5 to 3.5 meters in diameter
which can produce 1-10 kW of electricity at
their optimal wind speed (Tummala et al.,
2016). Fig. 3 shows the classification of wind
turbines based on rotor diameter. Table 1
demonstrates the classification of wind
turbines based
applications.
on
power
rating
and
Small scale wind turbines mainly can be
classified based on the axis of rotation i.e.,
vertical and horizontal.
Vertical Axis Wind Turbines (VAWT):
Vertical axis wind turbines are those whose
rotor axis is in vertical direction. These
turbines do not have any yawing mechanism or
self-starting capability. The generator location
for these turbines is on ground and their height
of operation is very low, hence making them
easier for maintenance. The ideal efficiency for
these turbines is more than 70%. The vertical
axis wind turbines are classified into two major
types:
(i) Darrieus Wind Turbine: The Darrieus
wind turbine is a type of vertical axis wind
turbine which consists of a number of
straight or curved blades mounted on a
vertical framework. These turbines work
from the lift forces produced during
rotation.
(ii) Savonius Wind Turbine: Savonius wind
turbines are drag based wind turbines
consisting of two to three scoops. These
turbines have an ‘S’ shaped cross section
when looked from above. As they move
along the wind, they experience lesser
drag and this difference in drag helps these
turbines to spin. Due to the drag, the
efficiency of these turbines is less when
compared to other types of turbines.
Fig. 1: Classification of wind turbine
according to capacity (Tummala et al.,
2016)
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Table 1: Wind turbine classification based
on power rating and applications.
Scale
Power rating
Micro
50W to 2 kW
Small
2 kW to 40
kW
40 kW to 999
kW
More than 1
MW
Medium
Large
Rotor
diameter
Less than 3
m
Application
3 m to 12 m
Homes and farms
12 m to 45
m
46 m and
larger
Village power,
Hybrid system
Central station wind
farms
Remote
Horizontal Axis Wind Turbines (HAWT):
Turbines whose rotor axis is in the horizontal
direction are called as horizontal axis wind
turbines. Unlike vertical axis wind turbines,
horizontal axis wind turbines have the ability
to self-start and yaw. These turbines are highly
dependent on wind direction and hence they
are generally operated at higher heights than
the VAWT. The ideal efficiency for these
turbines is between 50% and 60%.
Today most of small wind turbines are found
to be traditional horizontal axis wind turbine,
however vertical axis wind turbines are also a
growing type of wind turbine in the small scale
wind market. Nevertheless, some small wind
turbines are designed to work at low wind
speeds, but in general small wind turbines
require a minimum wind speed of 4m/s for
better performance.
3. Effects of Design Parameters on
Performance of Small Scale Wind Turbines:
In Small scale HAWT, much emphasis was
given on the factors such as tip speed ratio,
rotor speed and pitch angle for a specific
aerofoil which affect the performance of wind
turbine. There is a big research potential of
wind direction effect, wind turbulence
intensity and wind gust. It was also reported
that variable pitch with VAWT would result
with higher power coefficient.
A 3-bladed turbine of rotor diameter 2.1 m was
tested in a wind tunnel up to a wind speed of
13m/s. At various wind speeds, the values of
tip speed ratio (TSR) varied from 2 to 8 and the
maximum Coefficient of performance (Cp) of
0.2 occurred at TSR 6. It was also observed
that at a particular wind speed, the maximum
power value decreased with the increase in
yaw angle (Freere et al., 2010).
Singh et al. (2013) observed that the rotor
touched the Cp values up to 0.l, 0.217 and
0.255 with the wind speeds of 4, 5 and 6 m/s
respectively whereas the baseline 3-bladed
rotor targeted 0.052, 0.112 and 0.15 at these
wind speeds as shown in Fig. 2. This shows
that the two bladed rotors have a better Cp in
the low wind speed range of 3 to 7 m/s. At the
optimum pitch (β=18°), the two-bladed rotor
produced more than double power than the
base line rotor. Only at the pitch angle of 15°
and at a wind speed of 4 m/s, the power output
of the base line rotor coincided with that of the
two-bladed rotor.
Fig. 2: Minimum power coefficient of the
turbine as a function of wind velocity at
different pitch angle (Singh et al., 2013)
Design and characterization were studied of a
small-scale wind energy portable turbine
(SWEPT), of 39.4 cm rotor diameter operating
below the wind speed of 5 m/s by Kishore et
al, (2013). Maximum coefficient of
performance of 14% was obtained at optimal
tip speed of 2.9m/s. It had low cut in wind
speed of 2.7m/s and which gave 0.83 W of
electric power at the rated wind speed of 5m/s.
It was also observed that the diffuseraugmented SWEPT of length approximately
the same as the turbine's diameter could
produce 1.4–1.6 times higher power output
than a SWEPT without diffuser.
A very small scale, 4-bladed wind turbine have
a rotor diameter is 500mm, and having
NACA2404 airfoil profile was studied by
Hirahara et al. (2005). The results showed that
the turbine has a good efficiency in wind speed
range of 8–12 m/s with net efficiency and
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power coefficient as 0.25 and 0.36
respectively. It also shows good performance
at lower tip speed ratios. The maximum power
coefficient was about 0.40 when the tip speed
ratio was 2.7.
Duquette et al. (2003) had conducted a
numerical study and found that increase in
power coefficients at lower tip speed ratios was
observed with increase in the solidity. Also, the
power coefficients increased with the increase
in the blade number at a given solidity as
shown in Fig. 3. An increase in the solidity
from the conventional 5–7% to a range of 15–
25% yielded higher Cp values while lowering
tip speed ratio at maximum Cp to 2–4. Due to
lower tip speed ratios reduce structural
requirements, blade erosion and noise levels.
max. The tunnel blockage effect was small for
small TSR, and BF approaches a constant
value at a certain TSR, at which point the
blades act like a solid wall. It was observed that
the tunnel blockage effect and the decay rate of
BF are larger for the 12-blade turbine than the
6-blade for the same TSR. It was also
determined that no blockage correction is
necessary for β=25°, and the blockage
correction is less than 5% for BR less than 10%
and for TSR less than 1.5.
Fig. 3: Optimum design maximum Cp versus
tip-speed ratio for various blade numbers (By
Blade element momentum theory analysis)
(Duquette et al., 2003)
Fig. 4: Relationships between Cp and TSR
under six different β for 12 blades, at U=8 m/s
and BR=28.3 % (Chen and Liou, 2011)
A study on small scale HAWT having
NACA4415 profile blades was carried out in
order to investigate the effects of tunnel
blockage on the power coefficient in wind
tunnel tests by Chen and Liou (2011). The
blockage factor (BF) was determined by
measuring the velocities at different points in
the wind tunnel and the studies were carried
out on a 6-bladed turbine. It was observed that
the blockage effects increase as TSR and BF
increase, and β decreases. A Relationships
between Cp and TSR under six different β for
12 blades, were plotted as shown in Fig. 4
found that smaller the β value, larger the Cp
A small HAWT studied by Mayer et al. (2001)
and reported that for a pitch angle of 0°, there
is a longer idling period due to the very high
angle of attack and the idling period decreased
with the increase in blade pitch angle. It was
seen that at the pitch angle of 20°, shortest start
was obtained.
The AF 300 airfoil was associated with 8 other
airfoils designed for low Reynolds application
for small horizontal axis wind turbines was
studied by Singh et al. (2012). They plotted
L/D ratio, CL values at different angles of
attack for those 8 airfoils with AF300 as shown
in Fig. 5.
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Fig.5: L/D ratio, CL values at different angles
of attack plotted for 8 different blades (Singh
et al., 2012)
For different angles of attack, the forces of lift
and drag were calculated and pressure
distributions over the surface of the airfoil
were obtained. The maximum lift coefficients
were obtained at the stall angle of 14°. Flow
visualization showed that flow stayed fully
attached to the airfoil surface from Re as low
as 56,000 at an angle of attack 8° and
maintained a fully attached flow up to 14°
angle of attack for Re as low as 75,000.
A small wind turbine blade using the blade
element momentum (BEM) method for a three
bladed, Bergey XL 1.0 turbine, with 2.5 m
diameter rotor, up wind orientation, rated
power of 1000 W at 11m/s wind speed and tip
speed ratio of 5.85 and SD 7062 airfoil was
made by Song et al. (2014). Blade was tested
at the original designed pitch angle and also at
5° and 9° pitch angles. The new blades showed
better aero dynamic performance in high speed
wind conditions but under low wind speeds,
the original blades showed better performance.
The original blade was predicted to have
higher Cp than the new blades at designed
pitch (0°) and tip speed ratio λ less than 4.5,
whereas at higher λ the new blades were
predicted to have higher Cp values as shown in
Fig. 6.
The new blades at 5° pitch produced the
highest power at wind speeds over 9 m/s, while
the new blades at 9° pitch produced less power
over all, but performed best at low wind
speeds.
Fig. 6: BEM predictions of power coefficient
for the new blades at different overall pitch
angles, compared to the original Bergey
blades (Song et al., 2014)
4. Conclusions:
Nevertheless, utility scale wind turbines are
serving to harness the wind energy but Smallscale wind turbines can serve a better option
for harnessing wind energy due to they are cost
effective, easy to manufacture, portable safe
and environmental friendly. World is in
gesture of switching toward the green energy
resources for fulfilling its power needs and
research in the field of SWT is one of the
milestone in wind energy generation. After
going through the reported literature,
following substantial conclusions can be
drawn:
It is observed that unitary scale wind turbine
has its impact on the climate of world but it
is not clear that the impact on environment
due to large scale wind turbine is directly
connected or just a correlation.
The blade characteristic is a function of
wind speed, yaw angle, with and without a
nose cone. It also observed that at a
particular wind speed, the maximum power
value decreases with the increase in yaw
angle. At various wind speeds, the values of
TSR vary from 2 to 8 and the maximum Cp
is 0.2 at a TSR 6.
The BEM theory prediction is more
accurate for large scale wind turbines than
small scale due to Reynolds number and
three dimensionality effects (Separation
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delay at the in-board sections radial flow
and down wash effect).
The two bladed rotors have a better Cp in
the low wind speed range of 3 to 7 m/s. At
the optimum pitch (β=18°), the two-bladed
rotor produces more than double power than
the base line rotor. Only at the pitch angle
of 15° and at a wind speed of 4m/s, the
power output of the base line rotor coincides
with that of the two-bladed rotor. Maximum
coefficient of performance is 14% obtained
at optimal tip speed of 2.9m/s for wind
tunnel.
The turbine (rotor diameter is 500 mm and
4 bladed) has a good efficiency in wind
speed range of 8–12 m/s with net efficiency
and power coefficient as 0.25 and 0.36
respectively. It also shows good
performance at lower tip speed ratios. The
maximum power coefficient was about 0.40
at tip speed ratio 2.7.
An increase in the solidity from the
conventional 5–7% to a range of 15–25%
yielded higher maximum Cp values while
lowering tip speed ratio at maximum Cp to
2–4.
References:
[1]. Chen TY, Liou LR. (2011) Blockage
corrections in wind tunnel tests of small
horizontal-axis wind turbines. ExpTherm
Fluid Sc; 35(3):565–9.
[2]. Duquette M.M and Visser KD (2003) ,
‘Numerical Implications of solidity and
blade number on rotor performance of
horizontal
scale
wind
turbines’,
Transactions of the ASME , Vol. 125
[3]. Fiedler BH and Bukovsky MS (2011),
‘The effect of a giant wind farm on
precipitation in a regional climate model’,
Environmental Research Letters, Vol.6,
No.4.
[4]. Freere P, Sacher M, Derricott J, Hanson B.
A low cost wind turbine and blade
performance. Wind Eng2010; 34(3):289–
302.
[5]. Hirahara. H, Hossain MZ, Kawahashi M,
Nonomura Y (2005), ‘Testing and
performance of very small wind turbine’,
Renewable energy, Vol.30 pp. 1279-1297
[6]. Kishore R.A, Coudron T, Priya S (2013),
‘Small Scale Wind Energy Portable
turbine (SWEPT)’, Journal of wind energy
and industrial aerodynamics, Vol.116, pp
23-31.
[7]. Mayer C, Bechly ME, Hampsey M, Wood
DH. (2001) The starting behavior of a
small horizontal-axis wind turbine.
RenewEnergy; 22(1):411–7.
[8]. Singh RK, Ahmed MR (2013) , ‘Blade
design and performance testing of a small
wind turbine rotor for low wind speed
applications’, Renewable Energy, Vol.50
pp 812-819.
[9]. Singh RK, Ahmed MR, Zullah MA, Lee
Y-H. (2012) Design of alow Reynolds
number airfoil for small horizontal axis
wind turbines. RenewEnergy; 42:66–76.
[10] Song Qiyue, Lubitz William David.
(2014) Design and testing of a new small
wind turbine blade. J Sol Energy Eng;
136(3):034502.
[11] Tummala A, Velamati R.K, Sinha D.K,
Indraja V, HariKrishna V (2016), ‘A
review on small scale wind turbines’,
Renewable and Sustainable Energy
Reviews, Vol.56 pp. 1351-1371.
[12] Wang C and Prinn RG (2010), ‘Potential
climatic impacts and reliability of very
large-scale wind farms’, ‘Atmospheric
Chemistry and physics’Vol.10, No.4.
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On-Off Control Based Maximum Power Point Tracking of Wind Turbine
Equipped by DFIG Connected To the Grid
Rahul Gangwani1*, Om Prakash Bharti2, R. K. Saket3, Shiv Lal4
1,,4
Department of Electrical Engineering, GEC Banswara, Rajasthan, (327001), India
2,3
Indian Institute of Technology (Banaras Hindu University) Varanasi, U.P., (221005), India
Corresponding Author: Email: *rahulg.eee15@itbhu.ac.in, +91-7891288020
Abstract: This paper presents An on-off Control method which is based on maximum power point tracking
and anticipated to control the rotor side converter of DFIG based wind turbine connected to the grid. The
Grid Side Converter is controlled in such a way to assure a smooth DC voltage as well as ensure sinusoidal
current on the network. The performance analysis to the new developed DFIG based WT Matlab Simulink
model with MPPT based on-off control is assessed with the conventional Matlab Simulink model, which
demonstrate the enhanced performance output of newly developed model as compared to the traditional
model.
Keywords: DFIG; Wind turbine; MATLAB SIMULINK models.
Abbreviations: DFIG: Doubly Fed Induction Generator, VSC: Voltage Source Converter, WEC: Wind
Energy Conversion.
I.
INTRODUCTION
The study of increasingly alternate energy
sources, requirements for electric energy is
growing very fast. Amongst the available
alternative energy sources, wind energy, solar
energy, plus fuel cells have strained considerable
attention. Supplementary, all of these alternate
energy sources are also of renewable nature.
Among the mentioned alternate energy sources,
wind power generation systems have been the
most cost competitive alternative. For the first
decade of the 21st century, India emerged as the
2nd leading wind power market in Asia. More
than 2,100 MW wind capacity projects were
added in the financial year 2010–11. The installed
capacity increased from a modest base of 41.3
MW in 1992 to reach 28,700 MW by December
2016. Because the route, as well as the speed of
winds, may differ from position to position as
well as occasionally, the variable speed wind
turbine technology offers inherent advantages
over the fixed rate one [1].The DFIG is worn in
cycle with the wind turbine to produce electric
energy. The DFIG through the use of the two back
to Back converters, rotor side and grid side
converters can deal with a wide variety of wind
speeds by injecting a compensating variable
frequency current component in the rotor circuit.
Its facilitates both super and subsynchronous
operations of DFIG. It is well known that the
Induction machine is widely used in industrial
application due to its low cost, the simplicity of
construction and low maintenance cost. Such type
of mechanisms can be used for an electric
production wherever the momentum of the prime
mover is steady, i.e., just above the synchronous
speed. On the other hand, it is a fact that the wind
speed varies drastically depending upon the
environmental conditions and time of operation.
Thus, there is a significant margin of speed
variation. Such large margins of speed variation
make wound rotor induction machines suitable for
generation of wind energy [2]. In addition to its
significant speed variation, the wound rotor
induction machine offers the additional benefit of
bidirectional move of the rotor power which
depends on the rotor speed and field speed [3].
The DFIG is fundamentally a wound rotor
induction machine capable of operating in super
synchronous as well as subsynchronous mode.
The compensation of DFIG more than the
permanent speed induction generators is enhanced
power excellence, concentrated mechanical stress
as well as fluctuation and advanced energy
capture [4].The operations of DFIG associated
with the grid are helped with the help of rotor side
and grid side converter. It is the accountability of
the inverter connected to the rotor side to provide
the necessary complementary frequency to uphold
the stator frequency at a constant level, in spite of
variations in the mechanical power. The control of
DFIG presents a twofold crisis to compensate the
speed variations and reactive power. The stability
and presentation of the overall setup are to be
preserved in the face of model uncertainties,
external noise, a variety of the internal machine
parameters and speed. The primary question for
the research to carry forward is the ways by which
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the available energy at a given wind velocity can
be harnessed to its maximum.
II.AN OVERVIEW OF WIND TURBINES
A wind turbine is a mechanism that converts
kinetic energy as of the wind into mechanical
energy. If the mechanical energy is used to create
electrical energy, the machine may be named a
wind generator or wind changer. If the mechanical
energy is wont to drive machines, for example to
grinding grain or pumping water, the device is
predicted a windmill or wind pump. Today's wind
turbines are manufactured in a range of vertical
and horizontal axis types. Wind turbine system
can be categorized by the nature of their
operation, i.e., either fixed speed or different
speed. For fixed-speed wind turbines, induction
generator is straight linked to the grid. For the
reason that the speed is approximately set to the
grid frequency and most probably not
controllable. It is not probable to store the
turbulence of the wind in the form of energy
rotational. In favor of a variable-speed wind
turbine, the generator is controlled by power
electronic apparatus, which makes it probable to
control the rotor speed. The power variations
caused by wind variations can be more or less
engrossed through changing the rotor speed, and
thus power variation originating from the wind
conversion and the drive train can be reduced.
Hence, the power quality impact caused by the
wind turbine can be improved compared to a
fixed-speed turbine.
the wound rotor induction machine, which is
shown in Figure 1(b). This type of generator can
be defined as a fraction (~30%) of the rated
power. But the system ensures competent power
conversion appropriate to variable rotor speed,
which adjusts automatically by prevailing wind
speeds [5]. The primary benefit of doubly-fed
induction generators, while used in wind turbines,
is that they permit the amplitude as well as the
frequency of their output voltages to be
maintained at a constant value, despite what the
speed of the wind blowing on the wind turbine
rotor is. As doubly-fed induction generators
frankly associated with the AC power network
and stay at the back coordinated at all times with
AC power network. Further compensation
includes the capability to control the power factor
(e.g., to uphold the power factor at unity) while
keeping the power electronics devices in the wind
turbine at a moderate size. In the subsynchronous
operating mode, the stator of the DFIG supplies
power to the grid. In the super-synchronous
operating mode, both stator output power and the
rotor slip power are fed into the grid. A variable
speed wind turbine with full-size converter along
with doubly fed induction generator is exposed in
Figure 1. However, the converter has to be
intended for the rated power of the turbine. This
problem can be taken care of by using the DFIG,
which has a converter connected to the rotor
winding of the wound rotor induction machine
(Figure 1(b)). Rated power has been reduced to
(25% - 35%) in the case of DFIG. The main
components of the wind turbine are given as
follows.
A. Primary observation of the DFIG Based Wind
Turbine
The mechanical power which is produced by a
wind turbine is proportional to the cube of the
wind speed, i.e., Pm ∞ v3. Here Pm is the
mechanical power of the wind, as well as v, is the
velocity of the wind speed. The maximum power
which is received through the revolving speed of
the wind turbine defer from different wind speeds.
For this reason, the operation of variable speed is
necessary to maximize the energy. Two
fundamental concepts exist for variable speed
turbines. The first ideas are an electric generator
with a converter connected to the stator windings
along with the grid network which is shown in
Figure 1(a). For the rated power of the wind
turbine, the converter is to be designed. A
generator is a synchronous machine which is
frequently a permanent magnet. On behalf of the
direct drive concept, a wind turbine using a DFIG
has a converter associated to the rotor windings of
(a)
(b)
Fig. 1. Variable speed wind turbines (a) with
full-size converter (b) with a DFIG[3]
(i) Drive Train along with Aerodynamics:
The drivetrain has a turbine, gearbox, shafts and
other mechanical components of the wind turbine;
a multi-mass (in general two mass) model to be
used for dynamic studies of wind turbines through
DFIG [6]. A simplify aerodynamic model is
sufficient when the speed and pitch angle changes
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on the aerodynamic power during the grid faults.
For stability investigation, the drive train system
has to be approximated by the at least a two massspring as well as damper model while the system
response to massive disturbance [7]. There is a
flexible shaft during the turbine, and generator
masses are associated.
(ii)Pitch Angle Control System:
The “Pitch Control” is a technique to
mechanically regulate the blade pitch angle to
change the curve of the power coefficient to the
turbine [8]. PI control is used to realize the pitch
angle, in servomechanism model using time
control Tservo, accounts for the realistic response in
the pitch angle control System. For the period of
the grid faults how quick the aerodynamic power
can be reduced to stop more speed is determined
by the velocity of altering limit.
B.Modeling of the Wind Turbine
Here wind turbine model is discussed for optimal
operations of the wind turbine at different wind
speeds [9,18]. It has to operate at its maximum
power coefficient (CPoptimum=0.3-0.5), i.e., at a
constant tip speed ratio, proposed for operation
approximately it's maximum power coefficient.
The aerodynamic power generated by a wind
turbine is given as follows.
Pwindturbine
Pair
1
Pm Ar v3C p ,
2
Cp
A=Swept area of the blades (=πR2),
Tip ratio speed, v = wind velocity
T rotating speed of the rotor, =
Pitch angle, R= Radius of the area
covered through the blades
Cp = wind turbine energy coefficient.
III. AN GENERAL IDEA OF THE DFIG
OPERATING PRINCIPLE
The overview and operating principle of DFIG
discussed in this section is also mentioned in [10,
18]. The structural diagram of DFIG with
converters is shown in Figure 2. The AC/DC/AC
converter comprises two components: the rotor
side converter Crotor as well as network area
converter Cgrid. These converters are voltage
source converters that utilize forced commutation
power electronic devices (IGBTS) to synthesize
AC voltage from DC voltage source. A capacitor
connected to DC side acts as a DC voltage source.
The generator slip rings are linked to the rotor
side converter, which shares a DC link with the
grid side converter in a so-called back-to-back
configuration. The wind power captured by the
turbine is converted into electric power by the IG
and is transferred to the network using stator as
well as rotor windings. The control system affords
the pitch angle command, along with the voltage
commands for Crotor as well as Cgrid to control the
power of the wind turbine, DC bus voltage plus
reactive power or voltage at grid terminals. [11].
When the rotor speed is higher than the rotating
magnetic field from the stator, the stator induces a
high current in the rotor. The quicker the rotor
rotates, the extra power will be transfer as an
electromagnetic force to the stator, furthermore, in
turn, converted to electricity that is feed to the
electric network. The velocity of the
asynchronous generator will differ with rotating
force functional to it. Its dissimilarity from
synchronous speed in percent is called generator’s
slip. With rotor winding short-circuited, the
generator at full load is only a small percentage.
Using the DFIG, slip control provides the rotor
plus grid side converters. At high rotor speeds, the
slip power is recovered and delivered to the
network, resultant in high overall system
efficiency. If the rotor speed range is determined,
the ratings of the frequency converters will be
small equated with the generator rating, which
helps in reducing converter losses and the system
cost [12].Because the mechanical torque
functional to the rotor is constructive for power
production and since the rotation speed of the
magnetic flux in the air gap of the generator is
definite in addition to constant for an invariable
frequency network voltage, the sign of the rotor
electric power output is a function of the slip sign.
Crotor, as well as Cgrid, have the capability of
generating or absorbing reactive power can be
employed intended for controlling the reactive
power or the grid terminal voltage. The pitch
angle is controlled to limit the generator output
power to its standard value in support of high
wind speeds. The grid provides the necessary
reactive power to the generator.
IV.MPPT CONTROLLER
Maximum power point tracking is an efficient
method of extracting generated power from the
generating systems used by grid-connected
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inverters, solar battery chargers, and wind energy
conversion system. Wind energy is dependent on
weather, topology, and environment. It is essential
to choose the best place where the quality of air
can produce more electricity. Then it is difficult to
wind turbine to provide 60% of power wind
speed. Wind energy conversion system also has
other losses like mechanical friction as well as
low generator`s efficiency. So the amount of
power output from WECS depends on the tracked
wind power. Therefore, a maximum power point
tracking control is required [13].
ratio error) with guaranteed properties of
attractiveness and stability. An on-off Control
method based maximum power point tracking is
planned to manage the rotor side converter of
wind turbine equipped with doubly fed induction
generator connected to the grid.
A. Controller Design
This approach supposes that the WECS reacts
sufficiently fast to the variation of the lowfrequency wind speed; this happens in the case of
low-power WECS. Thus, for ensuring the optimal
energy conversion, it is sufficient to feed the
electrical generator with the torque control value
corresponding to the steady-state operating point
placed on the ORC. To this end, an on-offcontroller-based structure can be used to zero the
difference opt , where is given by
the low-frequency component of the wind speed,
v: [17]
r R
v
B. Rotor side converter based On-Off control:
Fig. 2.Basic diagram of Doubly Fed Induction
generator with converters [18]
V. ON-OFF CONTROL
Several research works have been presented with
different power/voltage control of the DFIG based
wind energy conversion system associated to the
grid with battery storage. These control diagrams
are usually based on vector control notion with
conventional PI controllers due to their simplicity
and easy implementation [14] [15]. Fuzzy logic
and adaptive fuzzy controllers have also been
used in the power/voltage control loop [16]. The
Classical controllers for wind energy conversion
systems (WECS) can be developed for more
effective strategies based on intelligent control
technique. On-Off control is a robust control
scheme aiming at captured power maximization of
DFIG-based WECS connected to the grid with
battery storage. This technique superposes the
tracking of the optimal torque value [17].The
control objective can be formulated as an
optimization problem, in which an objective
function is maximized or minimized, to extract the
maximum power from the wind energy. There is a
specific complexity concerning the On-Off
control, concerning the description of a switched
constituent (following the sign of the tip speed
For ensuring the maximum power point tracking
an On-Off supposes that the WECS reacts
sufficiently fast to the variation of wind speed (see
Fig. 3). An On-Off controller can be used to zero
the difference between the optimal tip speed ratio
and the actual tip speed ratio [19]:
opt
The on-off objective is to make the difference
between the optimal tip speed ration and the exact
tip speed ratio as small as possible with regulating
the rotor speed according to the wind speed.
The control law u has two components:
Temref = ueq + un
Where the equivalents control ueq as defined:
ueq = 0.5π R 3
C p (opt )
iopt
With: A = 0.5π R 3
vs2 = Avs2
C p (opt )
iopt
and i is the
gearbox ratio, un is an alternate, high-frequency
component, which switches between two values, α and +α, α>0:
un = α sign ( )
Component ueq makes the system operated at the
optimal point, whereas un has the role of
stabilizing the system behavior around this point,
once reached. The control law associated with the
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diagram in Fig.3 provides the steady state torque
reference. The control input has, in this case, a
large spectrum; the zero-order sample-and-hold
(S&H in Fig.3) has been introduced to limit the
loop switching frequency. If this frequency is too
large, the control loop becomes inefficient. The
zero order S&H element is approximated as a first
order low-pass filter with a time constant TS&H =
Ts/2, where Ts is the sampling period of the S&H.
In Fig.3 the nonlinear part consists of an On-Off
relay (“sign” block).The control of the rotor side
converter is illustrated in Fig.3; the reference i qref
is derived from the high-speed shaft Ωh and
measured wind speed v by tuning the On-Off
controller based maximum power point tracking
(MPPT). Thus, by adding a PI regulator in the
loop control of the d-axis and q-axis rotor currents
is realized, as shown inFig.3 [19].
voltage of the DC bus capacitor. For the grid-side
controller, the d-axis of the rotating reference
frame used for d-q transformation is aligned with
the positive sequence of the grid voltage. This
controller consists of measuring the d-q
components of AC currents to be controlled as
well as the DC voltage. Elsewhere the DC/DC
buck-boost bidirectional converter controlled
voltage source. This converter maintains constant
dc-link voltage as a reference value during
discharge/charge current from/to batteries bank.
[19]
Fig. 4: Direct bus control scheme [19]
The output of the DC voltage regulator is the
current reference Idgc_ref for the current regulator.
The current corrector controls the magnitude and
phase of the voltage generated by the converter
Cgrid (Vgc). The grid side controller is presented in
Fig. 5.
Fig.3.Rotor side converter based on-off control
scheme [19]
C: Inverter and direct bus voltage control:
The direct bus voltage is given by the following
equation [19].
1
Vdc I c dt
c
With: Ic = Idc – In
With Vdc and Idc are the direct bus voltage and
current respectively and In is the three-phase
currents supplied to the grid. The control scheme
of the direct bus voltage is presented in Fig. 4.
The grid-side converter is wont to regulate the
Fig. 5: Grid side control scheme [19]
VI. SIMULATION AND RESPONSE OF
THE DFIG SYSTEM
Figure 6 represents the detailed doubly fed
induction generator Matlab diagram and voltage
(Pu) at DFIG terminals presented in Figure 7.
Furthermore, Figure 8 shows the active power
delivered. The reactive power requirement of
the DFIG is presented in Figure 9. DC link
voltage (Pu) at the conventional link capacitor
of DFIG is presented in Figure 10.
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Fig. 9(b): Reactive Power Q v/s time from
conventional model
Fig. 6.Detailed DFIG wind
turbine diagram
Fig.10 (a). DC link voltage
Fig. 7.Voltages at the DFIG
terminals
Fig.10 (b). DC bus link voltage Vs. time from
conventional model
ACKNOWLEDGMENT
Fig. 8(a).Active power delivered
Fig.8 (b). Active Power P Vs. time from
Conventional model
The authors acknowledge the partial
financial support from the Indian Institute of
Technology (Banaras Hindu University),
Varanasi (U.P.) India for carrying out this
work.
Appendix: Simulation Data
Table 1: DFIG parameters
Parameters
Power
Stator resistance Rs
Rotor resistance Rr
Stator phase inductance
Ls
Rotor phase inductance
Lr
Generator inertia J
Friction factor f
Values
1.5 MW
0.023 Ω
0.016 Ω
0.18 H
0.16 H
0.0685 kg m2
0.01 N ms
VII.CONCLUSION
Fig. 9(a).Reactive power requirement of
the DFIG
The concept of MPPT has been proposed here to
achieve the goal of tracking maximum power at a
given wind velocity. To accomplish the MPPT
from the wind system, the MPPT block in
coordination with the rotor control block acts to
maintain the torque to the value that is optimum
for extracting the maximum power output from it.
The energy conversion device which is used in
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wind turbine systems is Doubly Fed Induction
Generator. Therefore, a doubly fed induction
generator was modeled as an energy conversion
device. The modeling included the verification of
developed model with that of the generator
present in the library of the MATLAB/ Simulink.
The results were better than of the model in the
MATLAB library. Further to achieve a double-fed
induction generator the modeled generator was
incorporated with rotor side converters and
controllers. The results obtained showed that the
system could perform well at average wind speeds
while the results were inconsistent with that of
expected values at lower and higher wind speeds.
REFERENCES:
[1] “Global Wind Statistics 2016”, Global Wind
Energy Council, February 2017.
[2] “Indian wind energy outlook 2012”, Global wind
Energy council, November 2012.
[3] Om Prakash Bharti, R.K. Saket, S.K.
Nagar,”Controller design for DFIG driven by
Variable speed Wind turbine using static output
feedback technique,” Engineering, Technology &
Applied Science Research, Vol. 6, No. 4, 2016.
[4] Lee, C, “Fuzzy-logic in control-systems: Fuzzy
logic controller, Part I,” IEEE Trans Syst Man
Cybern, 1990.
[5] Shabani, A. Deihimi, “A New Method of
Maximum Power Point Tracking for DFIG Based
Wind Turbine,” 25th International Power System
Conference, 2010.
[6] Abram, Perdana, “Dynamic Models of Wind
Turbines,”
Chalmers
University
of
Technology/Ph.D. Thesis, Goteborg, Sweden,
2008.
[7] Andreas, Petersson, Stefan Lundberg, “Energy
Efficiency Comparison of Electrical Systems for
Wind Turbines,” Chalmers University of
Technology.
[8] Ake Larsson, “The Power Quality of Wind
Turbines,”
Chalmers
University
of
Technology/Ph.D. Thesis, Goteborg, Sweden,
2000.
[9] S. Masoud Barakati, “Modeling and Controller
Design of a Wind Energy Conversion System
Including a Matrix Converter,” University of
Waterloo/Ph.D. Thesis, 2008.
[10] O. P Bharti, R.K Saket, S. K Nagar, “Reliability
Analysis of DFIG Based Wind Energy Conversion
System,” ‘ICCAE 17’, February 18-21, 2017,
Sydney, Australia.
[11] Hsing Chen Chiung, Hong Chih-Ming, Cheng FuSheng. Intelligent speed sensorless maximum
power point tracking control for wind generation
system. Int J Electr Power Energy Syst 2012.
[12] Munteanu I, Bratcu AI, Cutululis NA, Ceang E.
“Optimal control of wind energy systems: towards
a global approach,” Springer; 2008.
[13] Ackerman T. “Wind power in power systems,”
Chichester, UK: John Wiley & Sons; 2005.
[14] Blaabjerg F, Teodorescu R, Liserre M, Timbus
AV.
“Overview
of
control
and
grid
synchronization for distributed power generation
systems.” IEEE Trans Ind Electron 2006.
[15] Munteanu I, “Contributions to the optimal control
of wind energy conversion systems,” Ph.D. Thesis.
Galati, Romania: “Dunarea de Jos” University of
Galati; 2006.
[16] Om Prakash Bharti, R. K. Saket, S.K. Nagar,
“Controller Design of DFIG Based Wind Turbine
by Using Evolutionary Soft Computational
Techniques,” Engineering, Technology & Applied
Science Research, Vol. 7, No. 3, 2017, 1732-1736.
[17] Z. Wang, Y. Sun, G. Li, and B.T. Ooi, “Magnitude
and frequency control of grid-connected doubly
fed induction generator based on a synchronized
model for wind power generation,” IET
Renewable Power Generation, 2010.
[18] Om Prakash Bharti, R. K. Saket, S.K. Nagar,
“Controller Design for Doubly Fed Induction
Generator
Using Particle Swarm
Optimization Technique,” Renewable Energy,
Science Direct, Elsevier 114 (Part B), 2017, 13941406.
[19] Sami Kahla, Youcef Soufi, Moussa Sedraoui,
Mohcene Bechouat, “On-Off control based particle
swarm optimization for maximum power point
tracking of wind turbine equipped by DFIG
connected to the grid with energy storage,”
International Journal of Hydrogen Energy, Volume
40, Issue 39, 2015.
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Advances in Green Composites: A Review
Ranjan Kumar Singh, Moti Lal Rinawa, Manoj Mittal
Engineering College Jhalawar, Rajasthan, India
Corresponding author: ranjankumar@live.com
1Government
Abstract: The inevitable decrease in the supply of petroleum-based resources significantly restricts
the sustainable development of wood adhesive industry. Thus, more and more attention has been
focused on the utilization of renewable materials. This paper reviews the properties of various natural
and the modification of technical fibers and resins for improving the performance of the natural-based
wood adhesives.
1. Introduction
Green composites can be defined as a biocomposite reinforced by natural fibers with
biodegradable matrices. The green composites
are degradable and have sustainable properties,
which can simply dispose without harming the
environment. Weathering causes degradation of
polymer composite through photo-radiation,
thermal degradation, photo-oxidation and
hydrolysis. These processes result in changes in
their chemical, physical and mechanical
properties.
The development of green composites promotes
the use of environmentally friendly materials.
The use of green materials provides alternative
way to solve the problems associated with
agriculture residues.
Currently numerous research groups are
dedicated to minimising the environmental
impact of polymer composite production, where
the polymer matrices are derived from renewable
resources such as polylactide (PLA),
thermoplastic starch (TPS) or thermoset
matrices. Their high renewable content derives
from vegetable oils and, combined with natural
reinforced fibers (NF) to form environmentfriendly and fully degradable composite
laminates, they represent a potential substitute
for petroleum-based resins.
1.1 Ecobased Matrices
The wood-based polymer matrices availability is
nowadays very poor, but it rapidly grows as more
studies are done and more useful information’s
are given. The different kinds of bio based
natural polymer matrices used are listed below:
Thermoset matrices: polyols are compounds with
multiple hydroxyl functional groups available for
organic reactions, and they react with a large
number of chemical species, called curatives or
hardeners, to produce cross-linked thermoset
matrices. The most important oil used in polyols
production is soy bean oil, but also cashew nut
oil could give the same results. In order to
decrease the impact of its activity on global
warming, polyols can be also combined with
petroleum-based chemicals.
Thermoplastic matrices: the most commercially
available plastic matrix is the cellulose one,
which is properly toughened thus it is considered
a 100% bio-based matrix. Starch based polymers
and Poly (lactic acid) PLA are both available: the
employment of the first ones depends on the
ability to reduce their moisture absorption, while
the second one has similar properties to
polystyrene. Summing up, the employment of
these bio-based polymers depends on the
possibility to modify their properties in order to
obtain an easier processing and improve
toughness in the final green composites.
1.2 Natural Fibers
Natural fibers can be defined as bio-based fibers
or fibers from vegetable and animal origin. This
definition includes all natural cellulosic fibers
(cotton, jute, sisal, coir, flax, hemp, abaca, ramie,
etc.) and protein based fibers such as wool and
silk. Excluded here are mineral fibers such as
asbestos that occur naturally but are not
biobased. Asbestos containing products are not
considered sustainable due to the well-known
health risk that resulted in prohibition of its use
in many countries. On the other hand, there are
manmade cellulose fibers (e.g. viscose-rayon and
cellulose acetate) that are produced with
chemical procedures from pulped wood or other
sources (cotton, bamboo). Similarly, regenerated
(soybean) protein, polymer fiber (bio-polyester,
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PHA, PLA) and chitosan fiber are examples of
semi-synthetic products that are based on
renewable resources. In this paper also, the use
of fiber in food industries is excluded, where in
recent years these are frequently promoted as
dietary fibers or as supplements for health
products.
1.3 Hybridization
The hybrid systems for improved material or
structural performances is a well-known concept
in engineering design. A recent work has shown
that the properties of hybrid natural/glass
composite loading have been found to be an
effective way to improve composite's mechanical
properties and dimensional stability (moisture,
temperature, etc.). The stiffness or mechanical
properties of green composites can thus be
overcome by structural alignments that replace
material in specific positions for higher structural
performances.
2. Tables
In the table below, Table.1, a physical and
mechanical properties comparison between
natural and synthetic fibers is shown. As noted,
natural fibers have lower density values and they
fit perfectly for non-structural uses. In these
terms, natural fibers can replace synthetic ones
[1]
obtaining even more efficient results.
Table 1. Fibres’ mechanical properties
PROPERTI
ES
FIBERS
DENSITY
(g/cm^3)
TENSILE
STRENGTH
(MPa)
TENSIL
E
MODUL
US
(GPa)
JUTE
1.3-1.45
393-773
13-26.5
1.16-1.5
FLAX
1.50
345-1100
27.6-80.0
2.7-3.2
HEMP
-
690
-
0.6
BASALT
2.65-2.80
4000-4700
84-87
3.15
SISAL
1.45
468-640
9.4-22.0
3-7
E-GLASS
2.5
2000-3500
70
2.5
ARAMID
1.4
3000-3150
63-67
3.3-3.7
CARBON
1.7
4000
230-240
1.4-1.8
STRAIN
(%)
3. Processing and processability
Literature data on green composites show a clear
prevalence of wood end natural fibers in
combination with eco matrices like bio based
natural oils: this influences the information
available on processing and processability.
Typical processing techniques include extrusion
followed by injection or compression molding.
During the processing, temperature must not
exceed 200°C and the retention time of the
material exposed to high temperatures should not
be too long in order to avoid fibers' enervation.
Very common technologies for NF composite
materials are resin transfer molding, vacuum
injection molding, structural reacting injection
molding, injection molding and compression
molding.
4.
Future Research Directions
New environmental regulations and changing
governmental attitudes have stimulated the research
of new products and processes environmental
friendly. Natural fiber reinforced wood based
biodegradable polymer composites appear to have a
bright future for a wide range of applications. These
green composite materials with various interesting
properties may soon compete with the existing fossil
plastic materials.
References
Natural fiber reinforced biodegradable polymer
composites,
J.
Sahari,
S.M.
Sapuan,
Rev.Adv.Mater.Sci. 30 (2011) 166-174
[2] Natural Fiber Eco-Composites G. BogoevaGaceva,
M. Avella, et alt., M.E. Errico, POLYM. COMPOS.,
28:98–107, 2007.
[3] Use of Eco-Friendly Epoxy Resins From Renewable
Resources as Potential Substitutes of Petrochemical
Epoxy Resins for Ambient Cured Composites With
Flax Reinforcements. D. Bertomeu, D. GarciaSanoguera, O. Fenollar, T. Boronat, R. Balart.
POLYM. COMPOS., 33:683–692, 2012.
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Nonlinear coupling of Inertial Alfvén waves and cavity formation in
low beta plasmas
Moti Lal Rinawa
Govt. Engineering College Jhalawar-326023 (India)
Corresponding Author : motilal.rinawa@gmail.com
ABSTRACT
In the present paper, we have investigated nonlinear interaction of 3D- inertial Alfvén wave (3DIAW) and perpendicularly propagating magnetosonic wave for low -plasma = me / mi like
auroral regions. We have developed the set of dimensionless equations in presence of ponderomotive
nonlinearity due to 3D-IAW in the dynamics of perpendicular magnetosonic wave. Stability analysis
and numerical simulation has been carried out to study the effect of nonlinear coupling between waves
which results in formation of localized structure and density cavity, applicable to low beta plasmas
like auroral region. The result reveals that localized structure and density cavity becomes more and
more complex with time. From the obtained result, we observed the density fluctuations of ∼0.1n0,
consistent with the FAST spacecraft observation of inertial Alfven waves in the dayside aurora
reported by Chaston et al. [2000].
Keywords – Auroral region, cavitation, Inertial Alfvén wave
1.
Introduction
Alfvén waves (AWs) are ubiquitous in space
plasmas1. These were discovered for the first
time theoretically by Hannes Alfvén in 1942,
experimentally by Lundquist3 and observed by
Chaston et al. [2000]. Nonlinear waves and
chaos (NWC) are assumed to play vital roles in
the heating and acceleration of charged
particles [Goertz ,1984; Shukla et al.,1998;
Seyler and Liu, 2007], wave-wave / waveparticle interactions [ Hasegawa and Chen,
1976; Shukla et al, 2007].
The main objective of this paper is to evaluate
nonlinear coupling of 3D-IAW with PMSW to
study the density cavities and formation of
localized structure applicable to solar corona
and auroral region (Earth’s ionosphere). For
this purpose, using bi-fluid approach the
coupled dynamics of 3D-IAW and PMSW in
the presence of ponderomotive force has been
developed. The linear growth rate of the
modulational instability (M.I.) has been
obtained and then numerical simulation results
have been carried out to study the nonlinear
stage of this instability. The paper is further
organized as follows: dynamics of PMSW and
3D-IAW is presented in section-2 and 3
respectively. Stability analysis and numerical
simulation results are presented in section-4
and 5 respectively. Results are discussed in
section-6 and finally, the last section
comprises of the conclusion.
1.
Dynamics of Inertial Alfvén Wave
Let us consider the dynamics of 3D-IAW. The
ambient magnetic field is along the z axis.
r
i.e. B0 B0 zˆ , where B0 is the background
magnetic field. The wave is assumed to be
propagating in the x y z plane i.e.
r
k k0 r rˆ k z zˆ . Therefore, the dynamical
equation for 3D-IAW can be obtained as
follows,
The perpendicular components of electron and
ion fluid velocities for low - plasma
= me / mi are given as
e
n
c
c e k B Te
zˆ e1
zˆ
B0
B0
e
n0
(1)
2
2
2 ci i
t
cci0
cci2
Ti
Ti
zˆ ni1 i
ni1
B0
en0
B0 en0
(2)
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The parallel component of electron
fluid velocity is e z
eE z
i 0 m e
(3)
Furthermore, the (insignificant)
Parallel ion fluid velocity in the 3D-IAW field
is iz ieEz / mi .Taking parallel component
of Ampere’s law,
Jz
is the
pe
electron inertial length. Equation (8) gives the
dispersion relation as follows,
02
2
VA k0z
e
z
t
c
Where
2
n%e A%z
1
n0
t
2
2
2
(5)
Where n0 is the unperturbed plasma number
density and n%
e is the number density change
due to the presence of magnetosonic wave,
pe is the electron plasma frequency and c is
the velocity of light.
Making use of current density
r r
.J 0 and substituting the value of z from
equation (5) leads to
V 2
n% A%z
2
A 2 ci 2
1 e
2
t
c ci
t
n0 z
(6)
Taking a time derivative of Faraday’s
law,
2 Az
2 z
2
t 2
c
2
t
c
tz
(7)
Taking a derivative of equation (5) with
respect to ' r ' and derivative of equation (6)
with respect to z and substituting in equation
(7), one can get the dynamical equation for 3DIA
2 A%z
2 2 A%z
V 2
2
n 2 A%z
e2
A 2 ci 2
1
2
2
2
t
t
ci
t
n0 z 2
1
1
2
e
k0r 2 i2 k0 z2
(9)
c 2
Az
4
(4)
Taking a time derivative of equation (4) and
substituting the value of current density, J z
using equation (3) and taking a perturbation in
density as ne n0 n%,
one can get the
e
equation of electric field along the magnetic
field, z as below,
c
e
n n%e n%and
i
Where
i
c
pi
is an ion inertial
length. The term i k 0 z
2
appears due to the finite
2
in equation (9)
0
.
ci
Considering plane wave solution of equation
(8) as follows,
A%z
A z ( x , y, z , , t ) e
i ( k 0 r rˆ k 0 z zˆ 0 t )
(10)
Using equation (10) in equation (8), following
equation has been obtained for the case, when
z Az = k 0 z Az ,
i
201e2k0r2 Az
VA2k0z21 t
i2k0r
02e2 Az 02e2 2Az 2 Az n
i
Az 0
VA2k0z21 r VA2k0z21 r2 k0z z n0
(11)
2
2
0 2
VA k0 z
, k0r ( k0z ) is the
,
2
2
ci
ci
component of the wave vector perpendicular
(parallel) to B0 zˆ and 0 is the frequency of the
3D-IAW.
Where
2.
Dynamics of Magnetosonic Wave
Assuming the dynamics of low frequency
PMSW propagating along the x axis and
r
polarized in ‘y’ direction i.e. k k x xˆ and
r
E Eyˆ .The background magnetic field is
r
along the z axis i.e. B0 B0 zˆ , where B0 is
the ambient magnetic field.
The dynamical equation for PMSW is as
follows
(i) The equation of motion :
(8)
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And
r
v j
r
qj r
qj r
j kT j r n j r
E
( v j B0 )
Fj
t
mj
cm j
mj
n0
,
(11)
(ii) The continuity equation:
n r
r
.( nv ) 0 ,
t
(12)
(iii) Faraday’s law:
r
r r
1 B
( E )
,
c t
(13)
r
where v j is the velocity of species j = i, e (i =
ions, e = electrons), mj and Tj are the masses
and temperature of ions and electrons
respectively, c is speed of light in vacuum and
r
r r r qj r r
F j [ m j ( j .) j ( j B0 )]
is
the
c
ponderomotive force due to 3D-IAW. Putting
r
the values of v j in wave equation and taking '
y ' component of that, one can have
2 Ey
x 2
2
2
1 E y 1 E y 4 n0Te 2 ne
c 2 t 2 VA2 t 2
cB0 xt n0
4 n0e F jx 2 F jy
2
c icj m j icj2 m j
(14)
The electron continuity equation yields
ne
cE y
.
t n0
x B0
(15)
Components of ponderomotive force are
given as
Fex o
B0
2
me (1 ) 2 kr20 mi (1 ) kr20
Az
2k z20
8 (1 )k z20 x
4
2
Fiy
mi o (1 )2 kr20 2i 0
Az
1
4 B0 2(1 ) 2 k z20 1 ci x
(17)
Substituting Eqs. (15), (16) and (17) into Eq.
(14), one obtains
2
1 2 ne
1 2 2 2
x VA t n0
1 2 k 2
0r
4VA 2 B0 2
2k02z
02
1 m k
2
1
2
2
02
2
2
, k0r e
2
ci
,
Equation (18) represents the dynamical
equation of PMSW ( = ci ) whose righthand side represents ponderomotive force due
to 3D-IAW.
Equation (18), after normalization, and
equation (8) can be written in dimensionless
form as
Az
Az
2 Az
Az
i 1
2
i
n Az 0
t
r
r 2
z
(19)
and
2
2
2
n
2
t 2
x
2
2
(1 )2 (1 )kr20
2
Az ,
2 2
(1
)
k
x
z0
2
2
A
x
z
2
(20)
2
02
V A 2 k 0 r 2 e 2 k 0 z 2 1
. The normalising
are xn e , zn
parameters
tn
20 2
,
VA 2 k0 z 2 k0 r e 1
1
And
2
2
0r
2
0z
Cs
, and 0 , Az are
2
VA
the frequency and perpendicular magnetic
field of the 3D-IAW, respectively.
VA ( B02 4 n0 mi )1 2 is the Alfvén speed,
where n ne ni ,
Where
m
Fix i o
4 B0
mi
(18)
i
,
m (1 )2 kr20
Fey e 0
Az
4 B0
2 k z20
x
(16)
2
Az
k x 2
e
2 0 1 e 2 k 0 r 2
2
V A k0z
2
1
,
1
2k0 r e 2 k0 z
2
,
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For k0 r e 0.035 and 0 / ci 0.75 , one can
nn k 0 r 2 e 2 n0 and
B
n
2
0
1
4 k 0 r 2 e 2V
2
2 k 02 z
k 02 r
2
A
1
1
2
1
me
mi
k 2
02 r
k0z
k0r 4.66 106 cm1 ,
k0 z 3.52 106 cm1 and 0 2.16 103 sec1
calculate
1
2
B0
By considering adiabatic response of equation
(20), we get
2
n Az
(22)
Combining equation (22) into equation (20),
we get the following equation
A
A
2 Az
A
2
i z i1 z 2
i z Az Az 0
2
t
r
r
z
(23)
3.
Numerical Simulation
We have performed the numerical simulation
of equations (23) using 2D pseudo-spectral
method in a 2 r 2 z periodic
spatial domain with wave numbers of
perturbation, r , z =0.2 (normalized by xn1
and zn1 respectively) and (256 256) grid
points. The initial conditions of simulation are
Az r, z,0 Az 0 1 0.1cos r r 1 0.1cos z z
(26)
Where Az 0 = 0.5 is the amplitude of the
homogenous pump 3D-IAW. A finite
difference with predictor-corrector method
was utilized for the evolution in time with step
size of dt 5 10 5 . To solve system of
dimensionless equation (23), we have studied
the algorithm for the well-known modified
nonlinear Schrödinger (NLS) equation. The
accuracy was determined by consistency of the
2
number N Azk
in the case of NLS
. The normalising parameter values are
xn 2.74108 cmz
, n 1.16108 cmt
, n 0.296sec,nn 24.5cm3
and Bn 0.037 G .
4.
Results and Discussion
In Sec. 4, we have presented the stability
analysis of dimensionless equation (23) and
obtained equation (25).
Next, figure (3) represents 3D evolution of
density profile in the r– z plane at the same
time as in case of localized structures for
auroral region. From the figures (3), one can
observe that density dips are form x = 2.43, z =
2.57 (figure (3(a))), but as time increases,
density dips becomes intense and more
complex in nature. The magnetic field is
trapped in the regions of low density due to the
ponderomotive nonlinearity. Small-scale
length density cavities have been observed in
the auroral zone by Viking and Freja
spacecraft [Wahlund et. al, 1994; Chaston et.
al., 1999]. For the auroral region, we observed
the density fluctuations of ∼0.1n0, consistent
with the FAST observation reported by
Chaston et al. [2000].
References
1.
Alfvén, H. (1942), Existence of
electromagnetic hydromagnetic waves,
Nature (London), 150, 405.
2.
Benson, R. F. (1985), Auroral kilometric
radiation:Wave modes, harmonics, and
source region electron density structures,
J. Geophys. Res., 90(A3), 2753– 2784.
k
3.
Benson, R. F., W. Calvert, and D. M.
equation.
Klumpar (1980), Simultaneous wave
The values of 1 and 2 can be estimated from
and particle observations in the auroral
kilometric radiation source region,
the low- plasma parameters. For application
Geophys. Res. Lett., 7(11), 959– 962.
purpose in low- plasma , the typical
4.
Brodin, G. and L. Stenflo (1990),
parameters for auroral altitude of 1700 km
Coupling coefficients for ion-158
[Wu, Huang and Wang, 1996] are as follows:
cyclotron Alfvén waves, Contrib.
3
3
B0 0.3G, n0 5 10 cm , Te 1.16 104 K .
Plasma Phys., 30, 413-419.
Using these parameters, one can find:
5.
Champeaux, S., A. Gazol, T. Passot, and
8
VA 9.25 10 cm / s,
P. L. Sulem, (1999), in proceedings of
7
3
3
1
5
workshop
9.810
cm/s. on nonlinear MHD Waves
Vte 4.210 cm/s,e 7.5210 cm,ci 2.8710 sec , S 341.45cm,Cs the
and Turbulence, Nice, France, 1-4 Dec.
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6.
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3D simulations of fluctuation spectra of
the Hall-MHD plasma, Phys. Rev. Lett.,
102, 045004.
Ergun, R. E., et al. (1998), FAST satellite
observations of electric field structures
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2025–2028,
doi:
10.1029/98GL00635.
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Parametric decay of “Kinetic Alfvén
Wave” and its applications, Phys. Rev.
Lett., 36, 1362-1365.
Hollweg, J. V. (1999), Kinetic Alfvén
wave revisited, J. Geophys. Res. 104,
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(1999).
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Erd´elyi, P. J. Crockett, F. P. Keenan,
and D. J. Christian (2009), Alfvén waves
in the lower solar atmosphere, Science,
323, 1582-1585.
Modi, K.V. and R. P. Sharma (2013),
Nonlinear interaction of kinetic Alfven
wave with fast magnetosonic wave and
turbulent spectrum, Phys. Plasmas, 20,
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Roux, A., A. Hilgers, H. de Feraudy, D.
le Queau, P. Louarn, S. Perraut, A.
Bahnsen, M. Jespersen, E. Ungstrup, and
M. Andre (1993), Auroral kilometric
radiation sources: In situ and remote
observations from Viking, J. Geophys.
Res., 98(A7), 11,657–11,670, Seyler, C.
E., and K. Liu (2007), Particle
energization by oblique inertial Alfvén
waves in the auroral region, J. Geophys.
Res., 112, A09302.
Sharma, R. P., Kumar, S., and H. D.
Singh (2008), Nonlinear evolution of
kinetic Alfvén waves and the turbulent
spectra Phys. Plasmas 15, 082902.
Sharma, R. P. and H.D.Singh (2009),
Density cavities associated with inertial
Alfvén waves in the auroral plasma, J.
Geophysical Res., 114, A03109.
Shen, M. M and D. R. Nicholson (1987),
Numerical comparison of strong
Lagmuir turbulence models, Phys.
Fluids, 30, 1096.
16. Shukla, P. K., B. Eliasson, L. Stenflo,
and R. Bingham (2007), in Recent
Research Developments in Plasma
Physics, Ed. J.Weiland, Transworld
Research Network, Trivendrum,Kerala,
India, pp. 51-74.
17. Shukla, P. K., B. Eliasson, and L. Stenflo
(2012), Alfvénic solitary and shock
waves in plasmas, in multi-scale
Dynamical Processes in Space and
Astrophysical Plasmas, Eds.M. P.
Leubner and Z. Vörös, Astrophys. And
Space Sci. Proceedings (Springer,
Berlin), 33, 129-141.
18. Shukla, P. K., L. Stenflo and R. Bingham
(1999), Nonlinear propagation of inertial
Alfvén waves in auroral plasmas, Phys.
Plasmas, 6, 1677
19. Shukla, P. K., R. Bingham, J. F.
McKenzie, and I. Axford (1998), Solar
coronal heating by high-frequency
dispersive Alfv´en waves, Solar Phys.,
186, 61-66.
20. Stasiewicz, K., P. K. Shukla, G.
Gustafsson, S. Buchert, B. Lavraud, B.
Thide, and Z. KLo (2003), Slow
magnetosonic solitons detection by the
Cluster spacecraft, Phys. Rev. Lett., 90,
085002.
21. Stefant, R. J. (1970), Alfvén wave
damping from finite gyroradius coupling
to the ion
22. Wu, D. J., G. L. Huang, and D. Y. Wang
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Figure Caption
Figure 1 - The propagation dynamics of 3DIAW (auroral region) at time t=33.
Figure 1 - The propagation dynamics of 3DIAW (auroral region) at time t=33.
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Thermodynamic analysis of Factors affecting the Performance of Solar
Collectors
Arvind Kumara, Shiv Lalb and Harenderc*
a
Mechanical Engineering, Shiv Nadar University, Greater Noida-201314
b
Govt. Engineering College, Banswara, Rajasthan, India-327001
Corresponding Author: ak774@snu.edu.in , harender@snu.edu.in
Abstract
Thermodynamic analysis has been carried out to understand the performance of flat plate collector and
evacuated tube collector and to compare the same in the present study. Major parameters that affect the
performance of solar collector are absorptivity and emissivity of absorber, emissivity of glass cover,
temperature of absorber plate, collector tilt angle and number of glass covers. All the affecting factors
are analyzed numerically and graphs are plotted. It is analyzed that absorber plate temperature has
maximum impact over the heat loss from the solar collector. Absorber plate temperature can be
maintained at atmosphere temperature for the minimization of heat loss by increasing the mass flow rate
of the flowing fluid or by increasing the specific heat capacity of the fluid using nanoparticles.
Keywords: Solar-thermal energy, solar collector, Evacuated Tube, flat plate collector
1.
Introduction
Conventional sources of energy (coal, petroleum
etc.) are decreasing day by day and causing
global warming [1]. Since last 3 decades, nonconventional sources of energy (Solar Energy,
Wind energy, Tidal energy etc.) are being
investigated extensively [2-3]. Sun is the only
and vast source of solar energy that emits
electromagnetic radiation of 0.1-100 µm
wavelength at 5800K. Solar-thermal collectors
are the devices that absorb the solar irradiation
and transfer that heat energy to the fluid for
different applications. The main component of a
solar collector is absorber having maximum
absorptivity i.e. almost equal to unity.
Depending upon the type of absorber and
thermal losses from the absorber, there are many
types of solar collectors (Flat plate collector,
evacuated tube collector, concentrating collector
etc.) [4].
Absorber plate or tube temperature increases as
it absorbs the solar irradiation and some of
absorbed heat is radiated back to environment
due to emissivity of absorber plate. Radiative
heat energy is directly proportional to 4th power
of absolute temperature of absorber plate
therefore radiosity increases as the temperature
of absorber plate or tube increases. Efficiency of
the collector will be maximum when the total
absorbed heat energy is transferred to flowing
fluid inside the tube with minimum heat losses
to atmosphere.
In the present paper, every factor affecting the
performance of solar collector is analyzed
numerically. The performance of solar collector
depends mainly on solar intensity G (W/m2),
absorptivity of absorber tube (α), emissivity of
absorber tube (ε), tilt angle, and mean
temperature of absorber tube (Tpm) [5]. The
losses from the solar collector are optical losses
and thermal losses. Optical losses are due to
optical properties (transmissivity, reflectivity) of
glass cover [6]. Thermal losses are convective
heat loss and radiation heat loss. Convective heat
losses are minimized by using glass cover over
the absorber plate or tube and radiation losses
can be decreased by the maintaining the mean
plate temperature equal to ambient temperature.
Evacuation between absorber and glass cover
minimizes the thermal convective losses.
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2.
Mathematical Modelling
Useful heat gain of a solar collector can be
calculated as follows [7]: 𝑄 = (𝜏𝛼)𝐺 − 𝑈 (𝑇 − 𝑇
)
Where Q is useful heat gain, τα is transmittanceabsorptance product of absorber, G is solar
intensity (W/m2), and UL is overall heat loss
coefficient for the solar collector.
2.1 Flat plate collector
Overall heat loss coefficient of flat plate
collector UL is calculated as follows [8]:
𝑈
⎡
⎢
=⎢
⎢
⎣
𝑁
𝐶
𝑇
⎡
⎢
+ ⎢𝜎 ∗ 𝑇
⎢
⎣
∗
𝑇
−𝑇
𝑁+𝑓
.
+ℎ
⎤
⎥
⎥
⎥
⎦
+𝑇
⎤
⎥
⎥
[2𝑁 + 𝑓 − 1]
1
+
−𝑁 ⎥
𝜀
𝜀 + .005𝑁(1 − 𝜀 )
⎦
𝑇
+𝑇
f = (1- 0.04 hw + 0.0005 hw2) (1 + 0.091N),
C = 365.9(1- 0.00883 β +0.0001298 β2)
β=Collector Tilt angle (Degree), εp =absorber
plate emissivity (0.08), εg= glass emissivity
(0.9), hw = wind heat transfer coefficient (W/m2
o
K) = 8.55+2.56Vwind (m/s), Tpm =Absorber plate
mean temperature (K)
2.2 Evacuated Tube Solar Collector
Total heat loss from an evacuated tube solar
collector is due to radiation mainly and heat loss
by convection is negligible due to evacuation
between tube and glass cover.
Heat loss by radiation between absorber tube and
glass cover as follows [9]:ℎ =
𝜎𝜀
(𝑇
𝜀 𝐷(1 − 𝜀 )
1+
𝜀 𝐷
+ 𝑇 )(𝑇 + 𝑇 )
Where εp = absorber tube emissivity (0.08), εg =
glass emissivity (0.92), D=Absorber tube outer
diameter (37 mm), Dg = Glass cover diameter (47
mm), Tp = tube temperature (Kelvin), Tg = glass
temperature (Kelvin)
Useful heat gain of ISO 9459-2 evacuated tube
solar collector [10],
Qu=a1+a2 G+a3 (Twi-Ta)
The correlation coefficients for the ISO 9459-2
evacuated tube model are a1= 0.597, a2= 1.066,
a3= -0.208 and Twi is Tank Temperature and G is
solar irradiation for a day.
Instantaneous efficiency of evacuated tube solar
collector is written by [11]:
(𝑇 − 𝑇 )
(𝑇 − 𝑇 )
𝜂 =𝜂 −𝑎
−𝑏
𝐺
𝐺
𝑇= average of Inlet and outlet temperature in the
tube, 𝜂 =optical efficiency, Ta= ambient
temperature, a & b= heat loss constant of
evacuated tube collector
Maximum amount of absorbed heat energy can
be transferred by increasing the mass flow rate
(m) of flowing fluid inside the absorber or
increasing the specific heat capacity of fluid (cp)
[12].
Q= mcp(Tp-Tw)
Specific heat capacity of the flowing fluid can be
increased by using metal nanoparticles or carbon
nanoparticles in the flowing fluid [13].
𝑐 , = 𝜙𝑐 , + (1 − 𝜙)𝑐 ,
Where nf, n and f refer to nanofluid, nanoparticle
and base fluid, respectively. Specific heat of
nanofluid will be optimum at optimum volume
fraction of nanoparticles. As the specific heat
capacity cp increases, maximum amount of heat
can be transferred by the same mass flow rate.
3.
Results and Discussion
3.1
Effect of number of glass cover over
heat transfer coefficient for FPC
Losses of convective heat energy from a flat
plate collector have been minimized by
increasing the number of glass cover as shown
in figure [1]. By increasing the number of glass
cover, solar energy reflected by glass cover is
increased. Thus, the useful heat gain by the solar
collector decreases.
By increasing number of glass cover, maximum
amount of solar energy is reflected by glass
cover. Therefore maximum 2 glass cover should
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n=1, V=1
n=2, V=0
3.5
3
2.5
2
1.5
1
3
n=1
n=2
2.5
n=3
n=4
298
318
338
358
378
ABSORBER TEMPERATURE (K)
398
Figure 2. Effect of wind speed over heat
transfer coefficient for FPC
2
1.5
1
0.5
298
318
338
358
378
Absorber Temperature (K)
398
Figure 1. Effect of number of glass cover over
heat transfer coefficient for FPC
3.2
Effect of wind speed over overall heat
loss of flat plate collector
As the wind speed increases, Reynold’s number
increases. Therefore, natural convection is
turned to forced convection. Heat transfer
coefficient for forced convection is greater than
that for natural
convection. As heat transfer
coefficient increases, heat loss from the flat plate
collector increases.
Heat loss coefficient of flat plate solar collector
increases with increasing wind speed as shown
in figure [2]. Flat plate collector having one glass
cover is much affected by wind speed and flat
plate collector having two glass over, overall
heat transfer coefficient is not much affected by
increasing the wind speed as shown in figure [2].
3.3
Heat loss by radiation between
absorber tube and glass cover of ETC
Evacuated tube solar collector is the best
collector among all the collectors due to
minimum heat loss to atmosphere. There is
radiation heat loss from evacuated tube solar
collector and heat losses due to convection
between absorber tube and glass cover is
neglected. As there is vacuum between absorber
tube and glass cover, there is no fluid to transport
thermal energy from absorber tube. But there
will be heat losses too due to convection from
glass cover to ambient. Thus overall heat loss
confident of evacuated tube solar collector is
increased.
Overall heat loss coefficient
(W/m2K)
Heat Loss Coefficient (W/m2K)
3.5
n=1, V=0
n=1, V=4
4
HEAT LOSS COEFFICIENT (W/M2K)
be used for optimization of solar energy. More
the glass cover, greater will be the reflected
energy. After 2 glass covers, there is minute
change in heat losses as shown in figure [1] and
the heat losses due to convection and radiation
are increasing as mean plate temperature
increases. Heat losses from the absorber can be
decreased by maintaining the absorber
temperature almost equal to ambient
temperature. In the figure [1], n denotes the
number of glass cover.
1
Ta=288K
0.95
Ta=298K
0.9
Ta=308K
0.85
0.8
0.75
0.7
0.65
0.6
0
20
40
Tp-Ta
60
80
100
Figure 3. Effect of ambient temperature over
heat loss coefficient for ETC
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Difference between absorber tube temperature
and ambient temperature affects
the
performance of evacuated tube solar collector.
Higher the difference of temperature between
absorber tube and ambient, higher will be losses
as shown in figure [3]. Heat transfer coefficient
due to convection from glass cover to ambient is
taken as 12.7 W/m2 for calculation of overall
heat transfer coefficient.
3.4
Effect of absorber tube emissivity
over heat transfer coefficient for ETC
There are mainly three component of an
evacuated tube solar collector affecting the
performance of that evacuated tube solar
collector i.e. absorber tube, fluid to transfer the
absorbed heat and glass cover. Solar irradiation
is absorbed by absorber tube. Absorber tube
should have higher absorptivity. Higher the
absorptivity, greater will be the absorbed heat.
But by Kirchhoff’s law, the emissivity of a body
which is in thermal equilibrium with its
surrounding is equal to its absorptivity of the
body. For the higher value of absorptivity, a
surface coating is used over the absorber tube.
Ep=0.08
Ep=0.1
Ep=0.2
Ep=0.5
4
3.5
3
3.5
Heat gain by Evacuated Tube Solar
Collector vs Tank Temperature
Evacuated tube solar collector is the best
collector due to evacuation between absorber
tube and glass cover. There is no fluid
transporting thermal energy between absorber
tube and glass cover. Hence there will be no heat
losses due to convection. There will be only
radiation losses from the absorber tube.
Radiative energy from a body is directly
proportional to 4th power of absolute
temperature of that body. Heat losses due to
radiation from absorber tube depends on the
absorber tube temperature and emissivity of
absorber tube. Radiation losses can be
minimized by minimizing the absorber tube
temperature equal to ambient temperature by
increasing mass flow rate of fluid flowing inside
the absorber tube or by increasing the specific
heat capacity of the fluid using nanofluid. Lower
the tank temperature, Higher will be the useful
heat gain by evacuated tube solar collector as
shown in [figure 5].
30
Useful Heat gain (MJ/day)
Heat transfer coefficient (W/m2K)
4.5
absorptivity almost equal to unity, and lower the
value of emissivity.
2.5
2
1.5
1
0.5
25
20
15
10
5
0
298
318
338
358
378
Absorber Temperature (K)
398
Figure 4. Effect of absorber tube emissivity
over heat transfer coefficient
Emissivity of absorber tube affects the
performance of evacuated tube solar collector as
shown in figure [4]. Higher the value of
emissivity, greater the heat loss coefficient is.
Absorber tube should have higher the value of
298
318
338
358
tank Temperature (K)
378
398
Figure 5. Effect of tank temperature over useful
heat gain by ETC
The slope of useful heat gain by evacuated tube
solar collector to the tank temperature is
negative as shown in figure [5]. Useful heat gain
by evacuated tube solar collector is decreasing
as tank temperature is increasing. Higher the
tank temperature, greater will be the heat losses.
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Useful Heat gain (MJ/day)
Average temperature in the tube should be as
low as ambient for maximum heat gain.
Difference between tank temperature and
ambient temperature is taken as (dT) in the
figure [6]. As the temperature difference
between absorber tube and atmosphere
increases, useful het gain decreases and losses
increases. As the Absorber tube absorbs the solar
irradiation, temperature of absorber tube
increases. As the temperature of absorber tube
increases, loss due to radiation increases as
shown in figure [6]. More the difference of
temperature between tube and ambient, higher
will be the radiation losses and lesser will be
useful heat gain.
30
25
20
15
dT=20
dT=10
dT=0
10
5
0
0
5
10
15
20
Irradiation (MJ/m2)
25
Figure 6. Effect of ambient temperature over
Useful heat gain by ETC
3.6
Overall heat loss by ETC and FPC
FPC, n=1
Heat Loss coefficient (W/m2K)
4
FPC, n=2
3.5
ETSC
3
2.5
2
1.5
1
0.5
0
298
318
338
358
378
398
Absorber Temperature (K)
Figure 7. Comparison of Heat loss coefficient
for FPC and ETC
Heat loss coefficient for an evacuated tube solar
collector and flat plate collector are compared as
shown in figure [7]. Heat loss coefficient for flat
plate collector is higher than that for evacuated
tube solar collector. Therefore, heat loss from
flat plate collector is higher than that of
evacuated tube solar collector.
Heat loss by flat plate solar collector having (n =
1) glass cover is maximum and heat loss by FPC
having two glass cover is less than that of one
glass cover and greater than that of ETC. Heat
loss by ETC is minimum as there are radiation
heat loss only as shown in figure [7].
4.
Conclusion
By using selective coating or nano-coating on
absorber tube, absorptivity is maximized (=
0.92) so maximum amount of irradiation is
absorbed and temperature of the tube increases.
As the tank temperature increases, heat losses by
radiation as well as convection also increases.
Heat loss by convection is minimized by using
evacuation between absorber tube and glass
cover but heat loss by radiation does not need a
medium to propagate. Therefore heat loss by
radiation is not affected by evacuation. As the
temperature of absorber increases, heat loss by
radiation also increases. By maintaining the
absorber temperature almost equal to
atmosphere temperature, heat loss by radiation
can also be minimized. Absorber temperature
can be maintained almost equal to atmosphere
temperature by increasing the mass low rate of
the flowing fluid inside the absorber or by
increasing the specific heat capacity of flowing
fluid using carbon nanoparticles.
Evacuated tube solar collector is the more
efficient than flat plate collector having
minimum heat losses. For flat plate collector,
number of glass cover over absorber plate should
be 2 for optimization of absorbed solar energy.
More the number of glass covers, higher will be
losses due to reflection by glass cover. Heat
losses are not affected much by wind speed
having 2 glass cover over absorber.
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References
[1] D. Mills, Advances in solar thermal
electricity technology, Solar Energy 76
(2004) 19–31.
[2] D.Y. Goswami, S. Vijayaraghavan, S. Lu,
G. Tamm, New and emerging developments
in solar energy, Solar Energy 76 (2004) 33–
43.
[3] D.Y. Goswami, Solar thermal power
technology: present status and ideas for the
future, Energy Sources 20 (1998) 137–145.
[4] M.A. Sabiha, R. Saidur, Saad Mekhilef ,
Omid Mahian, Progress and latest
developments of evacuated tube solar
collectors, Renewable and Sustainable
Energy Reviews, Volume 51, November
2015, Pages 1038-1054.
[5] E. Zambolin, D. Del Col, Experimental
analysis of thermal performance of flat plate
and evacuated tube solar collectors in
stationary standard and daily conditions,
Solar Energy 84 (2010) 1382–1396.
[6] E. Zambolin, D. Del Col, An improved
procedure
for
the
experimental
characterization of optical efficiency in
evacuated tube solar collectors, Renewable
Energy, Volume 43, July 2012, Pages 3746.
[7] L.M. Ayompe, A. Duffy, Thermal
performance analysis of a solar water
heating system with heat pipe evacuated
tube collector using data from a field trial,
Volume 90, April 2013, Pages 17-28.
[8] Solar Energy, Principles of Thermal
Collection and Storage, S. P. Sukhatme, J.
K. Nayak (Page-124)
[9] Liangdong Ma, Zhen Lu, Jili Zhang,
Ruobing Liang, Thermal performance
analysis of the glass evacuated tube solar
collector with U-tube, Building and
Environment 45 (2010) 1959-1967
[10] G.L. Morrison, I. Budihardjo, M. Behnia,
Water-in-glass evacuated tube solar water
heaters, Solar Energy 76 (2004) 135–140.
[11] Tin-Tai Chow, Zhaoting Dong, Lok-Shun
Chan, Kwong-Fai Fong, Yu Bai,
Performance evaluation of evacuated tube
solar domestic hot water systems in Hong
Kong, Energy and Buildings 43(2011)
3467-3474.
[12] Indra Budihardjo, Graham L. Morrison ,
Masud Behnia, Natural circulation flow
through water-in-glass evacuated tube solar
collectors, Solar Energy 81 (2007) 1460–
1472.
[13] A.H. Elsheikh, S.W. Sharshir, Mohamed E.
Mostafa, F.A. Essac, Mohamed Kamal
Ahmed Alif, Applications of nanofluids in
solar energy: A review of recent advances,
Renewable and Sustainable Energy
Reviews, November 2017, In Press,
Corrected Proof.
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Reactive power control in distribution line by using
D-STATCOM
Dharaben B Ghamawala, Bhupendra R. Parekh
Department of Electrical Engineering, BVM Engineering College Vallabh Vidyanagar
Corresponding Author: dharabenghamawala@gmail.com
ABSTRACT
This paper discusses about the application of distribution static compensator (D-STATCOM) in
distribution line to control reactive power flow. In order to reduce the reactive power burden and to
mitigate other undesirable effects caused by inductive load, reactive power flow should be controlled
in distribution line. There is four different control strategies to control the power flow. Here a voltage
source converter type D-STATCOM based on instantaneous symmetrical component theory is
connected with distribution line to control power flow and Hysteresis current control is used to
generate the gate pulse for switching device of D-STATCOM. The distribution line and DSTATCOM are modeled using MATLAB-SIMULINK software. Finally, after the design, it provides
the effective full/partial reactive power compensation for variable load and also improve the power
factor.
Keywords: D-STATCOM, Distribution line, Variable inductive load, Reactive power control,
Instantaneous symmetrical component theory
reference current components. For this
1. INTRODUCTION
purpose, many control schemes are mentioned
Nowadays in distribution systems, major
in literature and some of these control
power consumption has been in reactive loads,
strategies are instantaneous reactive power
such as fans, pumps, electric motors, nonlinear
(IRP) theory, instantaneous symmetrical
loads etc. These loads draw lagging powercomponents, synchronous reference frame
factor currents and therefore increase reactive
(SRF) theory and Current compensation using
power burden in the distribution system.
dc bus regulation.
Moreover, In the presence of unbalanced
In this paper, a voltage source converter type
nonlinear loads, situation become worsen.
D-STATCOM is used to control the reactive
Excessive reactive power demand increases
power flow in the distribution line. For
feeder losses and reduces active power flow
generation of reference current, instantaneous
capability of the distribution system, whereas
symmetrical component theory has been used
unbalancing affects the operation of
and hysteresis current control strategy has been
transformers and generators. The reactive
used for generating the gate pulses for
power flow affects many parameters of
switching device of vsc type D-STATCOM.
distribution line, which introduced many
The D-STATCOM based on this control
technical issues in line. As these issues are very
scheme can provide reactive power control
important, reactive power compensation
under varying load condition
should be provided in the distribution line. The
2. D-STATCOM
conventional compensating devices fail to
D-STATCOM is a shunt connected
compensation under varying load condition
compensating power electronic device
and also suffer from many drawbacks. So, A
consisting of the
Distribution
STATic
COMpensator
VSC, DC energy storage, output filter and
(DSTATCOM) is one of most advanced,
coupling transformer/ interface reactor. VSC
versatile and suitable device for compensation
converts the DC voltage of capacitor storage
of reactive power and unbalance loading in the
device into the balanced set of three phase AC
distribution system.
output voltages. The generated voltages are in
The performance of DSTATCOM depends on
phase and interconnected with the utility grid
the control algorithm used for extraction of
through
interface
reactor/
coupling
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transformer. Fig 1 represents the generalized
connection of D-STATCOM to distribution
line. Proper adjustment of the magnitude and
phase angle of the D-STATCOM output
voltages allow effective control of reactive and
real power flow between the D-STATCOM
and distribution line.
Fig. 1. A generalized connection of DSTATCOM to Distribution Line.
If VI is equal to Vpcc, Zero reactive power
flow from D-STATCOM to distribution line
and the D-STATCOM does not absorb or
generate any reactive power. When V1 is
greater than Vpcc, the D-STATCOM performs
a capacitive reactance connected at its
terminal. The compensating current flows
from the D-STATCOM to the distribution line
and the device provide reactive power to
distribution line. If phase angle of voltage of
D-STATCOM is kept leading Vpcc, it can
supply real power to distribution line. By real
power flow exchange, it is used for mitigating
the internal losses of the inverter for
maintaining the voltage across capacitor
constant.
Different controllers and control strategies are
used for DSTATCOM to provide the control of
power flow in distribution line under dynamic
load varying condition .Here in this paper,
Instantaneous symmetrical component theory
based control strategy has been used to control
the functioning of D-STATCOM. The other
controllers having been used here are
Hysteresis Current controller (for Gate Pulse
Generation) & PI Controller (for maintaining
the voltage of Capacitor of VSC i.e. D.C. Link
Voltage constant).
3. CONTROL SCHEME
Instantaneous symmetrical component theory
is basically the symmetrical component theory
being applied to instantaneous voltages and
currents. The unbalanced voltages & currents
can be converted into 3-set of balanced
voltages & currents i.e. Positive sequence,
negative sequence & zero sequence
components by using this instantaneous
symmetrical component theory.
Here, the control strategy is used to generate
the reference currents. Two basic objective of
this proposed control scheme are :
The source should supply positive
sequence component of power only
To make supply currents balanced such
that:
isa + isb + isc = 0 (1)
As we assuming that the source current lag by
voltage by angle φ, then positive sequence
component of voltage also lag the positive
sequence current and we would obtained
equation (2)
(Vsb –Vsc-3βVsa) isa + (Vsc –Vsa-3βVsb)isb
+ (Vsa –Vsb-3βVsc)isc = 0
(2)
Where, β = 1/√6 tan φ
Now, if D-STATCOM is used to provide
reactive power compensation & source should
supply only average component of load power
P1 and the power losses occurring in switches
of VSI i.e Ploss would be supplied by source
itself , so equation (3) is obtained
Vsaisa +Vsbisb +Vscisc = Pl + Ploss
(3)
The equation for calculating reference value of
source currents are obtained in following
equation (4) , (5) and (6)by using equation (2)
isar = Vsa + (Vsb – Vsc ) β (P1 + Ploss) /
(Vsa^2 +Vsb^2 + Vsc^2)
(4)
isbr= Vsb + (Vsc – Vsca ) β (P1 + Ploss) /
(Vsa^2
+Vsb^2
+
Vsc^2)
(5)
iscr = Vsc + (Vsa – Vsb ) β (P1 + Ploss) /
(Vsa^2 +Vsb^2 + Vsc^2)
(6)
The reference compensenting current equation
to be provided by D-STATCOM would be as
shown in following equation (7), (8) and (9)
irca = ila – isar
(7)
ircb = ila – isbr
(8)
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ircc = ila – iscr
(9)
These compensating reference current irca ,
ircb , ircc are then compared with actual
currents ica, icb & icc respectively and then
hysteresis current controller is used to generate
the gate pulses of three legs of Inverter unit of
D-SATACOM.
4.
SIMULATIONS AND RESULTS
The
design
of
D-STATCOM
with
instantaneous symmetrical component theory
based control strategy is developed to control
reactive power flow in distribution line in
MATLAB SIMULINK software. The system
is employed with three phase programmable
voltage source with configuration of 415V, 50
Hz. The Main simulation circuit is shown in
Fig. 3, while the sub-circuits for control
scheme and D-STATCOM used in the
simulation are shown in Fig. 4 & Fig. 5.The
values of various parameters of Base system
and D-STATCOM considered are shown are
listed in Table I and II .
TABLE III. EFFECT OF LOAD
VARIOUS
PARAMETERS
DISTRIBUTION LINE
S
r
n
o
So
ur
se
vo
lta
ge
Powe
r
Dema
nd
P
(
K
W
)
1
41
5
1
0
Q
(
K
V
A
R
)
2
0
2
41
5
2
0
2
0
3
41
5
2
0
3
0
4
41
5
3
0
5
0
TABLE I.PARAMETER OF BASE SYSTEM
Source voltage & frequency
415 V (Line to Line ) , 50Hz
Total line resistance
0.1234Ω
Total line reactance
0.045mH
Load connected
Variable parallel resistive &
inductive
(R-L)load
Powe
r
Supp
lied
By
Sour
ce
P Q
(
(
K K
W V
)
A
R
)
1 1
0 9
.
.
1 7
4 1
1 1
9 9
.
.
9 4
3 8
2 2
0 9
.
.
2 1
8
3 4
0 7
.
.
7 9
5 3
Power
Receive
d
By
Load
ON
OF
Lo
ad
Vo
lta
ge
(V
)
Cu
rre
nt
(A)
Power
factor
P
(K
W
)
Q
(K
V
A
R)
9.
8
19
.6
8
41
1.
1
27.
1
0.457
19
.4
2
19
.4
2
40
7.
5
34.
41
0.511
19
.4
29
.0
9
40
7.
7
43.
29
0.569
28
.6
1
47
.6
3
40
3.
6
69.
39
0.540
TABLE II: PARAMETER OF D-STATCOM
Reference D.C. Link Voltage
800 V
D.C. link capacitor
1000µF
Coupling Inductance
0.025H
Pi Controller Constant
Kp = 0.85 , Ki = 5
Fig 2 Base System
Fig 3 Main Simulation Circuit With DSTATCOM
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Fig 5 Results of Real & Reactive Power Flow
of Source, D-STATCOM & Load
TABLE IV. SIMULATION RESULTS
POWER SUPPLIED BY SOURCE
S
r
n
o
Fig 4 Sub circuit of D-SATACOM
POWER RECEIVED BY LOAD
:
POWER SUPPLIED BY D-STATCOM:
S
o
u
r
s
e
v
o
lt
a
g
e
Power
Dema
nd
Power
Suppli
ed By
Source
Power
Supplied
By
DSTAT
COM
Power
Receive
d
By
Load
P
(
K
W
)
P
(
K
W
)
P
(K
W)
P
(
K
W
)
Q
(K
V
A
R)
1
.
1
7
3.2
1
0
.
3
4
1
9
.
8
7
2
0
.
3
19.
85
1
9
.
4
9
1
9
.
6
1
2
9
.
2
2
Q
(
K
V
A
R
)
0
.
5
0
2
0
.
5
4
2
.
3
2
6.8
3
0
.
9
48.
63
1
4
1
5
1
0
Q
(
K
V
A
R
)
2
0
2
4
1
5
2
0
2
0
3
4
1
5
2
0
3
0
4
4
1
5
3
0
5
0
9
.
6
5
1.1
7
1.6
Q
(
K
V
A
R
)
1
9
.
4
1
9
.
0
2
2
8
.
2
7
4
6
.
6
7
19.
46
29.
24
L
o
a
d
V
o
lt
a
g
e
(
V
)
Curre
nt
(A)
Po
we
r
fac
tor
4
1
2
.
6
4
0
9
.
9
4
0
9
.
9
4
0
7
.
3
13.35
0.9
98
26.86
0.9
95
27.03
0.9
97
40.26
0.9
96
:
5.
CONCLUSION
D-SATACOM based on instantaneous
symmetrical component control strategy is
proposed to control the reactive power flow in
distribution line. Hysteresis current controller
is used in this proposed structure for providing
gate pulses to switching device. The simulation
results show that D-STATCOM based on the
proposed strategy provides reactive power
compensation to distribution line with variable
load condition & the source supplies almost
negligible reactive power. therefore, source
power factor improves to 0.99.
REFERENCES
1. Arindam Ghosh, Gerard Ledwich, “Power
Quality Enhancement using Custom
Power Devices”, Kluwer Academic
Publisher, 2002.
2. N.G.Hingorani
&
L.Gyugyi,
“Understanding
FACTS”,
Standard
Publishers, Delhi, 2001.
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3.
4.
5.
6.
7.
8.
Vinay M. Awasthi , Mrs. V. A. Huchche
“Reactive Power Compensation using DSTATCOM” , IEEE 2016
U. Koteswara Rao, Mahesh K. Mishra &
Arindam Ghosh, “Control Strategies for
Load Compensation Using Instantaneous
Symmetrical Component Theory Under
Different Supply Voltages”, IEEE
Transactions on Power Delivery, 2008.
Sreejith S, Upama Bose, K. Muni Divya
Sree
Vachana,
Vallathur
Jyothi,
“Application of D-STATCOM as Load
Compensator
for
Power
Factor
Correction”,
IEEE
International
Conference on Control, Instrumentation,
Communication
and Computational
Technologies (ICCICCT), 2014
Bhim Singh, Alka Adya, A.P.Mittal, &
J.R.P. Gupta, “Modeling, Design and
Analysis of Different Controllers for
DSTATCOM”. IEEE transactions, 2008.
Pradeep Kumar, “Simulation of Custom
Power Electronic Device D-STATCOM –
A Case Study”, IEEE, India International
Conference on Power Electronics (IICPE),
2010.
Hirak K. Shah, P.N. Kapil & M.T.Shah,
“Simulation & Analysis of Distribution
Static Compensator (D-STATCOM)”,
IEEE, 2011.
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State of Health Assessment of Lead Acid Cells as a Function of
Conductance
Gauri1*, Manish Singh Bisht2, P.C Pant2, Rajesh Kumar3, R.P. Gairola4
1”
Dept. of Physics, Birla Campus, HNB Garhwal University Srinagar Garhwal, Uttarakhand, India
2
Ministry of New and Renewable Energy, Govt. of India, New-Delhi, India
3
National Institute of Solar Energy, Gurgaon, India
4
Dept. of Physics, HNB Garhwal University Srinagar Garhwal, Uttarakhand, India
*
Corresponding Author. E-mail: g.negi10@gmail.com
Abstract:
Low performing batteries/cells reduce the efficiency of whole battery bank. Sometimes the condition
becomes so severe that it results in malfunction of the whole bank. The state of health analysis of even a
single cell/battery through conventional load testing requires a lot of time and wastage of power. It is
required to discover and test a method of battery/cell testing which is quick, reliable and can be performed
on operational batteries. The aim was to investigate whether the conductance of the flooded and VRLA
lead-acid cell indicates real state of health of operational cells and if yes, could there be a reference value
of conductance for the cells of a particular capacity or not.
Key Words: Lead acid, conductance, Battery bank, State of health.
1.
Introduction:
Batteries form a very essential part of solar
photovoltaic applications. Being a very costly
device, it needs to be properly examined in terms
of capacity before being deployed in the field.
When a number of cells are connected in series
to form a battery bank, it becomes very essential
that all the cells have equal capacities and each
one is performing well. A low-performing cell
can lead to enhanced degradation of the whole
bank resulting in loss of both money and
valuable power generated by the solar modules.
In some cases it can even lead to breakdown of
the whole plant. But examining the state of
health of a battery is no easy task. For capacity
test on a battery it is required that the sample is
subjected to a number of cycles of charge and
discharge under controlled conditions at C10
rate. As per IEC and or BIS* standards a typical
capacity test would require about 40 hours per
cycle and to perform minimum 10 cycles is
mandatory for capacity test. It consumes a lot of
time as well as valuable power is wasted in
charging and discharging and when a complete
bank has to be tested it can take months to finish
the testing. The foremost problem isthat you
cannot examine the battery once being installed
as a bank. For capacity test on each cell you have
to dismantle the whole bank resulting in
interruption of whole SPV plant. And if the plant
is supplying crucial loads you do not have liberty
to do that. Normal field procedure of SOC
examination is to collect specific gravity
readings of the battery/cells, but these will only
serve as a superficial prediction of the level of
charge of the battery, but not provide
information on the storage capacity of the
battery. And in case it is a VRLA cell you have
to think of some other options. As batteries
degrade through field use, their capacity goes
down. The battery bank operator or owner is in
dark how to find the state of health of his bank
or the faulty battery of the bank which is not
performing well.
The aim of this article is to present and discuss
results for a relatively new method of examining
operational field batteries, under actual
conditions, which is quick, reliable and does not
involve any waste of power. This method is
based on assessment of state of health of a
battery though its conductance.
Conductance describes the ability of a battery to
conduct current. In scientific terms, it is the real
part of the complex admittance. Various test data
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have shown that at low frequencies, the
conductance of a battery is an indicator of
battery state-of-health showing a linear
correlation to a battery’s timed-discharge
capacity test result and trending this
measurement can be used as a reliable predictor
of battery end-of-life (H. Giess, 1999). This
paper also presents a reference value of
conductance for the flooded and VRLA lead acid
cells of a particular capacity so that they may be
used as reference to examine batteries of the
same capacity.
The use of conductance measurements to
evaluate automotive battery performance was
first reported in 1975 by Champlin [1]. It
demonstrated a strong positive linear correlation
between load tests and measured conductance
for automotive batteries. Since then impedance
and more recently conductance has been
attracting both users and manufacturers to
determine battery state-of-health [2-4]. Initially,
the conductance testing was limited to VRLA
cells only but later the interest expanded to
flooded cells and nickel-cadmium cells as
well[5]. Now a number of studies have been
published on this topic [6-12]. This research
work was carried out on two operational battery
banks of 240V, 1000Ah each, consisting of 120
cells of 2V, 1000Ah at National Institute of Solar
Energy, Gurgaon, Haryana (INDIA). One of
these banks was of flooded type while the other
one was of VRLA technology. These banks,
installed 2 years before, are connected to two
different inverters of 10KVA and 50KVA
respectively and are being used to power the
loads of the campus. Both inverters are hybrid
inverters and operate on grid as well as solar
power. Both the inverters are also connected to
the generator so that battery banks are not
consumed to higher DOD. These banks are also
provided equalizing charge once in a month to
ensure proper health. Regular maintenance and
topping up with water is also carried out as per
schedule.
2.
Measurement Technique:
For measurement 5 new samples of same type
and capacity as existing ones were purchased
from same manufacturer. These new batteries
were subjected to capacity test for 10 cycles each
at C10 rate and room temperature to have normal
filed conditions. The capacity test was
performed with the help of a Life Cycle Network
(LCN) Machine make Bitrode Corporation,
USA. It is a programmable power supply and
inbuilt load having automatic data collection
feature. It records voltage, current, Amperehour, Watt-hour and temperature at preset
intervals. At full charged conditions these
batteries were examined with the help of a
Battery Analyzer make Midtronics, USA. The
battery analyzer is a digital meter which when
attached to the sample provides voltage and
corresponding conductance values. Battery
conductance is measured by evaluating the
voltage response to a small, select frequency AC
current signal briefly impressed on the battery.
The resultant conductance measurement
provides pertinent battery information without
the need of bringing the battery to full discharge.
As a battery discharges, its conductance and
capacity are reduced with a simultaneous drop in
power in a predictable manner due to the
depletion of conductive active materials. The
value in conductance or any other Ohmic
measurement can be more directly described asAn increased internal resistance or reduced
measured conductanceof a cell results in a
reduction of the expected capacity or discharge
performance of the cell (W. Cantor et.al., 1998.).
Thus, conductance is an indication of battery
state of health as well as a function of the charge
state of a battery. The battery analyzer is
powered by a battery source installed inside and
does not draw any power from the bank. The
conductance values and corresponding value of
voltages were recorded.
A battery analyzer was now used to individually
examine in total 240 cells of both the banks and
conductance of the cells along with the
corresponding voltage was noted. The battery
bank was maintained at full charge during the
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testing and the specific gravity values denoting
charged conditions were also recorded. The
conductance values of the cells at a particular
voltage level were sorted to get maximum inputs
for same voltage and conductance.The
conductance values of the cells of battery banks
were compared with those of new ones. The cells
which showed significantly lower conductance
values than new batteries were tested for
capacity on Bitrode tester. Capacity test was
performed on such cells as per the standards and
the data was recorded. 10 random samples from
the remaining batteries which showed relatively
good conductance values were also examined
for capacity.
Data Analysis:
1094
1092
Capacity vs. Conductance
1090
1088
1086
1084
y = 0.0128x + 709.08
R² = 0.988
1082
1080
1078
1076
28600 28800 29000 29200 29400 29600 29800 30000
Fig. 1 Capacity vs. conductance of new flooded
cells
Capacity vs conductance
1180
1160
1140
1100
1080
31200 31400 31600 31800 32000 32200 32400 32600
Fig. 3 Capacity vs. conductance of unused
VRLA cells
Fig. 1 show the capacity vs. conductance values
of new and unused cells or reference cell of
flooded type. Each cell is having a capacity
greater than their rated capacity. The graph
clearly reflects that higher the capacity higher is
conductance. The correlation factor for the
above values comes out to be 0.988 which
denotes a linear relationship between the
capacity and conductance. Similarly Fig. 2
shows capacity vs. conductance plot for
comparatively healthy used flooded cells.The
capacity of these cells had degraded over time
and the same was reflected by their reduced
conductance and capacity values as compared to
the new cells.These are the cells which showed
good capacity and conductance values as
compared to the reference cells. It also supports
the claim that the capacity and conductance bear
a linear relationship with respect to each other.
Capacity Vs. Conductance
Capacity vs conductance
1000
800
600
y = 0.078x - 1112.4
R² = 0.9693
400
200
0
21000
22000
23000
24000
25000
y = 0.0651x - 949.07
R² = 0.9253
1120
26000
Fig. 2 Capacity vs. conductance of healthy used
flooded cells
900
800
700
600
500
400
300
200
100
0
22600
y = 0.231x - 4627.6
R² = 0.9693
22800
23000
23200
23400
Fig. 4 Capacity vs. conductance of healthy used
VRLA cells
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Fig. 3 Reflects the capacity vs. conductance plot
of reference VRLA cells denoting a linear
relationship between the two.
Fig. 4 also confirms the linear relationship
between capacity and conductance of used and
comparatively healthy VRLA cells.
During conductance testing some of the cells in
both type of banks were found to be having very
low conductance values as compared with other
batteries in the same bank. These cells were
identified and capacity tests were performed on
these. Fig.5 and fig. 6 represent capacity vs.
conductance plots of flooded and VRLA
technology respectively.
Capacity vs conductance
70
The above figures depict that even at very low
state-of-charge conductance bears a linear
relationship with the capacity.
Reference Value of Conductance:
Conductance of unused VRLA cells
32800
32600
32400
32200
32000
31800
31600
31400
31200
31000
30800
1
60
50
30
10
0
50
100
150
200
Fig. 5 Capacity vs. conductance plot of very
weak flooded cells
Capacity vs conductance
140
y = 0.8015x - 88.607
R² = 0.9386
60
40
20
0
50
100
2
3
4
5
Fig. 8 Conductance of unused flooded cells of
1000Ah
100
0
5
30000
29800
29600
29400
29200
29000
28800
28600
28400
28200
1
120
80
4
Conductance of unused flooded cells
20
0
3
Fig. 7 Conductance of unused VRLA cells of
1000Ah
y = 0.7301x - 59.557
R² = 0.9561
40
2
150
200
250
300
Fig. 6 Capacity vs. conductance plot of very
weak VRLA cells
Both the above figures depict that the
conductance values for 2V, 1000Ah cells of both
the technologies are above a certain mark in new
and unused cells. Considering Fig. 2 and Fig. 4
for used and comparatively healthy cells it is
confirmed that the conductance values lie in a
specific range. Though the results are not highly
accurate but they do specify a range in which the
conductance values should lie for a specific
capacity of batteries.
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3.
Conclusion:
The conductance value of a battery reflects the
integrity of inter-cell connections, ionic
conductivity of the electrolyte, specific gravity
of the cells and the actual battery state of charge.
The test results are the product of the internal
electrical resistance of the cells and reflect the
combined influences of the mechanical state of
health in the cells and the electrochemical
condition or efficiency of the grid/plate
structures.
As a battery ages, the positive plate will
deteriorate and change chemically adversely
affecting the ability of the battery to perform.
This normal aging process begins when the
battery is activated during the formation process
at the end of the battery production lineand will
continue for life of the battery.
For power provisions, this means that
conductance can be used to track changes and
detect battery defects, shorts, open circuits and
prolonged undercharging, which will reduce the
ability of the battery to perform. Conductance
test measurements become a valuable tool to
identify the point at which the battery is
approaching its end of service life. The test
results reflect that the conductance technology
may be a useful tool to examine new or field
batteries for their state-of-health. Conductance
bears a linear relationship with the battery
capacity which is a direct indication of battery
health. This linear relationship is maintained
even at low state-of-health of the batteries.
Using conventional load testing methods to
determine battery capacity requires time and
power whereas conductance testing method is
quick and reliable. Though exact capacity cannot
be predicted but it can provide a tentative idea of
battery health. It could prove useful for
examining batteries in large quantities such as
tenders or inspections where load testing seems
impossible for each sample.
References:
*BIS- www.bis.org
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
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14.
15.
16.
K.S. Champlin, Talk presented to 1975SAE
Off-Highway Vehicle Meet, Milwaukee,
WI, USA, Sept. 1975.
F.J. Vaccaro and P. Casson, Proc. 1987
INTELLEC Conf., pp. 128-135.
S. L. DEBardelaben, Proc. 1988
INTELLEC Conf., pp. 394-397.
D.O. Feder, Talk presented to 103rd
Convention
of
Battery
Council
International, Apr. 1991, Washington, DC,
USA.
M.J. Hlavac and S.J. McShane, Proc, 1993
Association American Railroads, Eastern
Region Meet, Orlando, FL, USA.
D.O. Feder, T.G. Croda, K.S. Champ& S.J.
McShane and M.J. Hlavac, J. Power
Sources, 40 (1992) 235.
D.O. Feder, T.G. Croda, K.S. Champlin and
M.J. Hlavac, Proc. 1992 INTELEC Cone:,
pp. 218-233.
G.J. Markle, Ptwc. 1992 INTELEC Co& pp.
212-217.
S.S. Misra, T.M. Noveiske, L.S. Holden and
S.L. Mraz, Pnx. 8th Annual Battery Cant
Applications and Advances, 1993.
M.J. Hlavac, D.O. Feder and D. Ogden,
Proc. American Power Con&, 1993, Vol. 1,
pp. 44-57.
B. Jones, From. Ilth Int. Lead Con& Venice,
Itab, I993.
D.O. Feder, M.J. Hlavac and W. Koster, J.
Power Sources, 46 (1993) 391.
H. Giess "Operation of VRLA Batteries in
Parallel
Strings
of
Dissimilar
Capacities", Proceedings
of
21st
Intelec, 1999
W. Cantor , E. Davis , D. Feder and M.
Hlavac "Performance Measurements and
Reliability of VRLA Batteries â ” Part II:
The Second Generation", Proceedings of
20th Intelec, 1998
D. Funk and E. Davis Battery Performance
Monitoring
by
Internal
Ohmic
Measurements, 1997
W. Ross and P. Budney "Development of a
Battery Run Time Algorithm and a Method
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for
Determining
its
Accuracy", Proceedings
of
17th
Intelec, pp.277 -283 1995
17. M. Troy , D. Feder , M. Hlavac , D. Cox , J.
Dunn and W. Popp Midpoint Conductance
Technology Used in Telecommunication
Stationary Battery Applications, 1997
18. M. Hlavac and D. Feder "VRLA Battery
Monitoring
Using
Conductance
Technology", Proceedings
of
17th
Intelec, pp.285 -291 1995
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CONTROL OF CURRENT AND VOLTAGE FOR MICRO GRID
Dhaval Subhashchandra Vyas, Bhupendra R. Parekh
Department of Electrical Engineering, BVM Engineering College Vallabh Vidyanagar
Corresponding Author: dhavalvyasrang@gmail.com
ABSTRACT
Utilization of Renewable Resources as a main stream sources of full fill the power requirements in
urban and rural areas of India and the world creates the challenge for electrical engineer to develop
effective control strategies for current and voltage control for micro grid operations which is presented
in this paper. This paper describes use of dq theory for control micro grid at different mode of
operation points which helps to achieve effective closed loop control in standalone operation of
Renewable resources and also in synchronism with grid.
Keywords—Distributed generation, Constant Current Control, Voltage control, PLL, PI Controller.
I.
INTRODUCTION
An increasing development and reduce energy
crisis, in electric power with the use of
renewable energy sources which plays a main
role for continuous power supply. Power
electronics are the enabling technology to
convert classical power systems into smart
grids, since they allow controlling the power
flows and bus voltages in the milliseconds
range.
AC-DC converters with bidirectional power
capability are the key elements in micro grids
and distributed generation systems. The
different configurations of variable speed wind
turbines need power converter
Structures based on two AC-DC converters.
Each converter needs active and reactive
power control capability in order to extract the
optimum power from the wind turbine while
exchanging the appropriate
reactive power with the power grid. Similarly,
photovoltaic systems need an AC-DC inverter
to inject the generated power into the grid.
Fig.1.Schematic diagram of the Micro grid
with Utility Grid
II.SYSTEM BLOCK DIAGRAM
A.Introduction:
Fig.1 shows the system diagram which micro
grid with utility grid. This system block
diagram consists of a micro grid and utility
grid with different storage system. Under
normal operation, each distributed power
generation inverter system in the Micro grid
usually works in constant current control mode
in order to provide a preset power to the main
grid. When the Micro grid is cut off from the
main grid, each distributed power generation
inverter system must detect this islanding
situation and must switch to a voltage control
mode. A controller was designed with two
interface controls:
1)
2)
For grid-connected operation
For intentional islanding operation
Fig.2. Schematic Diagram Of Grid-Connected
form Of Operation
B. Grid-connected Form Of Operation:
In grid-connected Mode Of operation,
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193
Connected through point of common
coupling.
Bi-directional flow.
Economic benefit by supplying excess
power to main grid.
Reduce fuel cost using the power from
main grid during low (night) load.
During grid connected operation providing a
constant current output. In this mode of
operation inverter is worked as a source and
supplying constant active and reactive power
to the load using constant current control.
Figure 3 shows the current control topology.
Using the current control strategy the inverter
equation is as follows,
consist a PI Controller to obtain v´d and v´q as
shown in figure 3.The controller output used to
inverted d-q voltages as shown in equation 3.
V 2 / 3 1/ 3 Vab
V
0 1/ 3 Vbc
(5)
VD cos sin V
VQ sin cos V
(6)
Transforming equation 1 into d-q reference
frame is,
The above equations defined coupled by d
and q current .the current controller now de
coupled so we got,
Fig.4. PLL Structure
D.Islanding Form Of Operation:
In this mode of operation when grid is removed
from the system and only inverter is fed to
supply and balanced the load. In this mode of
operation constant voltage control strategy is
used which as shown in Fig.5. The voltage
closed loop control work as a voltage
regulation by current compensation. The result
of the compensator are compared with the load
current and it’s fed in the PI regulator. The
error is accepted to a PI controller to find out
the modulation index value. The output of this
is considered as a reference signal for the
system.
Fig. 3.Constant Current Control Technique
C.Switch over between grid and islanded
mode of Operation:
The point at which the grid is disconnected and
without changing in standard parameters its
switch over to islanding mode. This is done by
synchronous reference frame PLL which
Fig.5.Constant Voltage Control Technique
III.SIMULATION ANALYSIS
A. Simulation Parameters:
a)
Grid Parameters
a.
Voltage – 440 Volts RMS
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194
b.
Frequency – 50 Hz
b)
Inverter Parameters
a.
DC Voltage – 1550 Volts DC
b.
Smoothening Reactor – R: 2Ω, L: 100
mH
c.
3 leg inverter with 6 IGBT’s
c)
Load Parameters
a.
3-Ph RLC Parallel Load with Y point
Grounded
b.
Voltage – 440 Volts RMS
c.
Frequency – 50 Hz
d.
Active Power – 10,000 watt, Reactive
Power – 100 VAR inductive
d)
LCL Filter Parameters
a.
L: 0.5 mH, C: 62 mF, L: 0.25mH
The system is simulated in mat lab 2013. It is
consisting of micro grid and utility grid both
are connected parallely. Three mode of
operation is here defined for this system.
B. Simulation Model:
Fig.7. Voltage & Current Waveform while
Inverter Supply to load
2) 0.1 to 0.2 sec - inverter synchronized with
Grid and both supplying to Load:
Fig.8. Voltage & Current Waveforms while
inverter + Grid supply to Load
Fig. 9. 0.2 to 0.3 sec -Only Grid supplying to
load(Figure-9):
Fig. 10. Voltage and Current waveform of
Load Bus(Figure-10):
Fig.6. System Simulation Model
C. Simulation Results:
Operation Time:
1) 0 to 0.1 sec - only inverter supplying to
Load
2) 0.1 to 0.2 sec - inverter synchronized with
Grid and both supplying to Load
3) 0.2 to 0.3 sec - only grid supplying to Load
1) 0 to 0.1 sec -Only Inverter supplying to
load:
Fig. 11. Voltage and Current waveform of
Inverter Bus(Figure-11):
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195
Fig. 12. Voltage and Current waveform of
Grid Bus(Figure-12):
d) P - watt and Q – var Balanced while power
supplying by Grid to Load
e) Voltage and Current Balanced while power
supplying by inverter + Grid to Load
f) P - watt and Q – var mismatch while
power supplying by inverter + Grid to
Load
Fig. 13. Active Power Measurement(Figure13
Fig. 14. Reactive Power easurement(Figure14):
D. Result Analysis:
a) Voltage and Current Balanced while power
supplying by inverter to Load
b) P - watt and Q – var Balanced while power
supplying by inverter to Load
c) Voltage and Current Balanced while power
supplying by Grid to Load
IV.CONCLUSION
As per describe control strategy, voltage and
current remains constant for 440v,50Hz
system for varying load condition and three
different mode of operation for micro grid
system model. Moreover active and reactive
power supply and demand also matches in two
out of three modes of operation and in future
control logic for balancing of P & Q for third
mode of operation will be develop.
List of Figures
1. Figure-1 : Schematic diagram of the Micro
grid with Utility Grid
2. Figure-2 : Schematic Diagram Of GridConnected form Of Operation
3. Figure-3 : Constant Current Control
Technique
4. Figure-4 : PLL Structure
5. Figure-5 : Constant Voltage Control
Technique
6. Figure-6: Fig.6. System Simulation
Model
7. Figure-7 : Voltage & Current Waveform
while only Inverter Supply to load
8. Figure-8 : Voltage & Current Waveforms
while inverter + Grid supply to Load
9. Figure-9 : Voltage & Current Waveforms
while only Grid supply to Load
10. Figure-10 : Voltage & Current waveforms
of Load Bus
11. Figure-11 : Voltage & Current waveforms
of Inverter Bus
12. Figure-12 : Voltage & Current Waveform
of Grid Bus
13. Figure-13 : Active Power Waveform for
Grid, Inverter & Load Bus
14. Figure-14 : Reactive Power Waveform for
Grid, Inverter & Load Bus
REFERANCES
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1. Irvin J. Balaguer, Student Member, IEEE,
Qin Lei, Shuitao Yang, Uthane Supatti,
Student Member, IEEE, and Fang Zheng
Peng, Fellow, “Control for Grid-Connected
and Intentional Islanding Operations of
Distributed Power Generation” IEEEI
INDUSTRIAL ELECTRONICS, VOL. 58,
NO. 1, JANUARY 2011
2. Agust Egea-Alvarez, Adri_a JunyentFerr_e and Oriol Gomis-Bellmunt “Active
and reactive power control of grid
connected distributed generation systems”.
3. Mr. Juan C. Vasquez, Mr. Joseph M.
Guerrero, Senior Member, IEEE “Adaptive
Droop Control Applied to Voltage-Source
Inverters Operating in Grid-Connected and
Islanded Modes”; IEEE transactions on
industrial electronics, vol. 56, no. 10,
October 2009
4. Sreelekshmi R S & Sunitha R “Analysis of
Inverter Fed Micro-grids For Different
Modes of Operation in Matlab/Simulink,” ,
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Energy Management ISSN (PRINT): 2231–
4407, Volume-2, Issue-1, 2
5. G. Adamidis1, G. Tsengenes1 and K.
Kelesidis1, “Three Phase Grid Connected
Photovoltaic System with Active and
Reactive
Power
Control
Using
“Instantaneous Reactive Power Theory”,
International Conference on Renewable
Energies and Power Quality (ICREPQ’10)
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Reactive Power Compensation using Static Synchronous Series
Compensator (SSSC) [A Review Paper]
Ruchirkumar Mehta, N. G. Mishra
Department of Electrical Engineering, Birla Vishvakarma Mahavidyalaya
Corresponding Authoor: ruchirsmehta@gmail.com
ABSTRACT
The power system has now a day become very complex and the load on the system is increasing
rapidly resulting in a major increase in reactive power absorption. Flexible Alternating Current
Transmission System (FACTS) devices are very useful in providing reactive power compensation to
the system. One such device is Static Synchronous Series Compensator (SSSC). The SSSC provides
series compensation to the power system through series voltage injection. This paper represents the
reactive power compensation and voltage regulation obtained by SSSC in the power system.
Simulation of the SSSC is carried out in MATLAB software. The control circuit comprises of d-q
transformation and PI controllers. The simulated converter circuit of SSSC has a six-pulse Voltage
Source Inverter (VSI) whose output AC voltage is fed into the system. The injected voltage is
independent from the line current. The injected voltage (compensating voltage) can lead or lag the
line current by 90° i.e. it can operate in both the inductive and capacitive region. The SSSC not only
provides reactive power compensation but also voltage regulation.
Key words- SSSC, Active power, Reactive power compensation, FACTS device, Voltage Source
Inverter.
is used instead of the DC capacitor and thus
I.
INTRODUCTION
resistive compensation in the transmission line
Today, there is need for fast and flexible power
is also obtained. The SSSC controls power
flow control in transmission system because
flow in steady state as well as improves
increase in utility deregulation and power
transient stability of the power system. The
wheeling requirement is expected in the future.
parameters of the power system are controlled
The power transmission system needs to be
by PI controllers. The reactive power
effectively operated and their utilization
compensation of the power system will reduce
degree needs to be increased by the utilities.
voltage drop and provide voltage regulation in
The FACTS devices like SSSC are used to
the power system. The injecting voltage can
prove their performance in terms of stability
emulate as inductive or capacitive reactance as
and reactive power compensation [1].
the injecting voltage is in quadrature with line
The SSSC can control both the active and
current. This paper presents mainly reactive
reactive power flow in the line. The
power compensation using SSSC [4].
compensating voltage is independent of the
II.
PRINCIPLE OF OPERATION OF
line current. The SSSC can produce threeSSSC
phase AC voltage at the desired fundamental
Transmission line inductance is compensated
frequency with controllable variable amplitude
by a series capacitor by presenting a lagging
and phase angle. Therefore, SSSC is having
quadrature voltage with respect to the
analogy with synchronous voltage source. The
transmission line current. The lagging
SSSC does not have sub synchronous
quadrature voltage works in opposition to the
resonance oscillations because it does not
leading quadrature voltage across the
resonate with inductive line impedance [6].
transmission line inductance. The inductive
The SSSC is also analogous to synchronous
reactance of the line is reduced due to the net
compensator as it can both generate or absorb
effect. The schematic diagram of SSSC is
reactive power from the system. It can also
shown in fig.1. The operation of SSSC is
provide real power compensation if DC battery
similar as it also injects quadrature voltage VC
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which is independent of the line current but
lagging in phase [5].
Where Vs and Vr are magnitudes of voltage
sources and 𝛿s and 𝛿r are the phase angles of
voltage sources Vs and Vr respectively.
Assume Vs = Vr.
𝛿= 𝛿s –𝛿r
(3)
Thus, the real and reactive power equations are
represented this way:
P=
𝐕𝟐
𝟏
𝐗𝐪
𝐗𝐋
𝐗𝐋
𝑽𝟐
Q= 𝑿
𝒆𝒇𝒇
Fig. 1: Static Synchronous Series
Compensator
Fig. 2: Two machine system with SSSC and
the phasor diagram of SSSC
Fig.2 shows Static Synchronous Series
Compensator (SSSC) for a two-machine
system and the associated phasor diagram. The
insertion of AC output voltage of the inverter
in the transmission line is performed by a
voltage source inverter (VSI) and a coupling
transformer. The SSSC controls the magnitude
and phase angle of this inserted ac
compensating voltage effectively. The
transmitted power Pq is a parametric function
of injected voltage. The real and reactive
power (P and Q) without SSSC at the receiving
end voltage are given respectively by
expressions (1) and (2). 𝛿 is the transmission
angle between the two machines.
P=
Q=
𝑽𝒔 𝑽𝒓
𝑿𝑳
𝑽𝒔 𝑽𝒓
𝑿𝑳
𝐬𝐢𝐧(𝜹𝒔 − 𝜹𝒓) =
(1)
𝑽𝟐
𝑿𝑳
(𝟏 − 𝐜𝐨𝐬(𝜹𝒔 − 𝜹𝒓)) =
𝐜𝐨𝐬 𝜹)
(2)
(𝟏 − 𝐜𝐨𝐬 𝜹) =
(𝟏 −
𝐬𝐢𝐧 𝜹 =
(4)
𝑽𝟐
𝟏
𝑿𝒒
𝑿𝑳
𝑿𝑳
(𝟏 − 𝐜𝐨𝐬 𝜹)
(5)
When the SSSC is operated in the inductive
mode the compensating reactance Xq is defined
to be negative and in the capacitive mode
compensating reactance Xq is defined to be
positive. Xeff is the effective reactance of the
transmission line including the variable
compensating reactance inserted by the
injected voltage source of the SSSC [3].
III.
CONTROL STRATEGY
The specifications and model parameters are
given below in table 1. There are four buses in
the given power system B1, B2, B3 and B4
connected in the ring mode. Two power plants
supplies phase-to-phase voltage 13.8 kV to the
power system. The transmission line voltage is
of 500 kV. The lengths of the transmission
lines Line1, line2, line3 and line4 are 150 km,
280 km, 150 km and 50 km respectively.
Table 1: Specification and parameters of
model
Specifications
System parameters
Generator G1 or
Machine M1
Generator G2 or
Machine M2
Transformer TR1
Transformer TR2
𝑿𝑳
𝑿𝒆𝒇𝒇
𝐬𝐢𝐧 𝜹
𝐬𝐢𝐧 𝜹
𝑽𝟐
𝑽𝟐
System phase to
phase voltage
2100 MVA, 13.8
kV
1400 MVA, 13.8
kV
2100 MVA, 13.8
kV/ 500 kV
1400 MVA, 13.8
kV /500 kV
13.8 kV
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Transmission line
voltage
Load
Base parameters
Line length
500 kV
2000 MVA
Base voltage= 500
kV
Base power= 500
MVA
Line1= 150 km,
Line2=280 km,
Line3= 150km,
Line4= 50 km
Fig. 3: Control system of SSSC
The above fig. 3 shows the control system of
the SSSC. First, line voltage V and line current
I
both from the bus are measured for
controlling the power flow in transmission
line. Active power Pact along with reactive
power Qact is calculated using values of line
voltage V1 and line current I1. Feedback signals
of the control loop utilizes these calculated
active and reactive power. Pref and Qref are the
ideal reference values provided for the system.
Pact and Qact are compared with the reference
values Pref and Qref. The error signals obtained
from this comparison are then forwarded to PI
controller. The PI controller reduces the steady
state error and eliminates inaccuracy of the
signals. The error is reduced to its least
possible values of signals and it is made sure
that actual calculated values Pact and Qact match
with the reference values Pref and Qref. Thus
power flow control is attained. These
controller results are then converted to abc
reference and forwarded to the pulse width
modulator (PWM).
Fig. 4: Simulated converter circuit of SSSC
The expressions of the calculated actual values
of real and reactive powers Pact and Qact are
given below:
Pact = Vd*Id + Vq*Iq
(6)
Qact = Vq*Id + Vd*Iq
(7)
Six high frequency signals are produced by
PWM. Control to the switches of Voltage
Source Inverter is provided by these signals.
The voltage source inverter (VSI) produce
three phase voltages using these signals. These
three phase voltages are injected into the
transmission line through series transformer.
Transmission line current is in quadrature to
this injected voltage. As shown in above fig.5,
active and reactive power can be fed or
absorbed using the compensator provided with
a DC voltage source in the converter circuit.
The SSSC converter circuit works along with
the control circuit [2,3].
IV.
SIMULATION OF SSSC
The two machine power system without
SSSC and with SSSC both are represented in
fig.5 and fig.6 respectively.
Fig. 5: Two machine power system without
SSSC
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Fig. 6: Two machine power system with
SSSC
Fig. 7: Active and reactive power at bus 3 for
system without SSSC (in p.u. value)
The results of the without SSSC power system
and with SSSC power sytem are shown in fig.7
and fig.8.
Fig. 8: Active and reactive power at bus 3 for
system with SSSC (in p.u. value)
From fig.8 and fig.9, it is observed that SSSC
increases the active power and does reactive
power compensation. The active power is
increased to 0.78 p.u. and reactive power is
compensated from 0.42 p.u. to 0.40 p.u. at bus
3 of the power system.
V.
The SSSC can effectively compensate the
reactive power of the power system. The
reactive power absorption at The active power
flow is also increased from 0.55 p.u. to 0.78
p.u. The SSSC can also be used for multimachine power systems. Active power and
reactive power both can be controlled by
SSSC. The SSSC can also provide
improvement in the voltage profile of the
power system. The SSSC also provides
stability to the power system.
REFERENCES
1. Mohammed abdul khader aziz biabani,
Mohd akram, Ikram ahmed shareef,
“Power System Stability Enhancement
using
Static
Synchronous
Series
Compensator”, International conference
on Signal Processing, Communication,
Power and Embedded System (SCOPES)2016, IEEE.
2. Pooja Nagar, S. C. Mittal, “Reactive
power
compensation
by
Static
Synchronous Series Compensator”, 2016
International Conference on MicroElectronics and Telecommunication
Engineering.
3. H. Taheri , S. Shahabi , Sh. Taheri , A.
Gholami , “Application of Synchronous
Static Series Compensator (SSSC) on
Enhancement of Voltage Stability and
Power Oscillation Damping”, IEEE 2009.
4. M. Faridi, H. Maeiiat, M. Karimi ,P.
Farhadi, H. Mosleh,”Power System
Stability Enhancement Using Static
Synchronous
Series
Compensator
(SSSC)”, Islamic Azad University-Ahar
Branch, Ahar, Iran, IEEE 2011.
5. Narain G. Hingorani, Laszlo Gyugyi,
“Understanding FACTS: Concepts and
Technology of Flexible AC Transmission
Systems”, IEEE Press, A John Wiley &
Sons, Inc., Publication.
6. Abdul Haleem, Ravireddy Malgireddy,
“Power Flow Control with Static
Synchronous
Series
Compensator
(SSSC)”, Proc. of the International
Conference on Science and Engineering
(ICSE 2011).
CONCLUSION
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Induction Motor Protection System Using Fuzzy Logic
Nirav M. Dudhat, Akshay A. Pandya
Department of Electrical Engineering, BVM Engineering College, Vallabh Vidhyanagar, Gujarat.
Corresponding Author: niravdudhat999@gmail.com
AbstractIn this paper the protection of three phase induction motor is simulated using fuzzy logic. Mainly in
system there are two types of faults which are electrical and mechanical fault. In mechanical faults broken
rotor bar, mass unbalance, air gap eccentricity, bearing damage, rotor winding failure, and stator winding
failure are there, where as in electrical faults unbalance supply voltage or current, single phasing, under
or over voltage or current, reverse phase sequence, earth fault, overload is there. From that six faults are
taken in this paper, which are over voltage, over current, voltage and current unbalance, low voltage and
temperature rise. When any of the fault is detected then the delay time is computed by fuzzy logic. If the
fault is not cleared after this time delay the system will send stop signal to motor. In the conventional
protection system, the time delay is predefined for various faults without considering the fault level. If
any temporary failure is detected in the system, motor should not stop. Similarly, if the system waits too
long to stop motor in critical faulty condition then it will lead to the serious defect. So, it is necessary to
set time delay optimally. By fuzzy logic the time delay is computed on the basis of fault level which was
not considered in the conventional protection system. In this paper different time delays are computed
for various faulty parameters. The time delay is obtained according to rule base. This proposed system
is effective and more reliable.
Keywords: Fuzzy logic, induction motor, motor protection, Simulink model.
I.
INTRODUCTION
In the modern era of industrialization, the most
essential part of the industries is electrical motor.
Mainly electrical motors types are AC and DC.
In AC motor fractional hp motors are used in
different home appliances and giant
synchronous and induction motor are used
widely in industrial applications which are up to
10,000 hp. It should be protected against
different electrical and mechanical faults for
serving their purposes smoothly. So it is
necessary to select the proper protection by
using the motor characteristic curve.
Induction motor is widely used in industrial
application because they are rugged, low cost,
low maintenance, reasonably small sized
reasonably high efficient, and operating with an
easily available power supply. They are more
reliable in operation but they are more subjected
to different types of undesirable faults.
Mainly Over voltage, over current, temperature
rise, low voltage, voltage unbalance and current
unbalance this type of fault occurs normally in
induction motor. This fault can be detected by
mechanical or electrical failures, signal
processing and artificial intelligence techniques.
In the conventional methods that detects
mechanical failures of induction motor by means
of mathematical models used one or more of the
stator current, speed, vibration level or winding
temperature values however, these methods may
be insufficient for complex and nonlinear error
conditions
that
cannot
be
modeled
mathematically Artificial intelligence methods
are useful in this type of problems.
Artificial neural networks, fuzzy logic, genetic
algorithms and their hybrids are known as soft
techniques.
In
conventional
protection
techniques relays are provided with some time
delay time without considering the fault level
while in case of fuzzy logic the time is calculated
as per the fault type and required step will be
taken in between 0 to 4.5 sec time span. If fault
persist after that that motor will stop.
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The human decision-making process can often
be implemented in complex systems with more
success than conventional control techniques
with use of this intelligence method like fuzzy
logic. In fuzzy logic the fuzzy rule base is
created on the bases of experience, observation
and mathematical equation. If the created rule
base is well and comprehensive then results will
be accurate and precise.
In this paper, the delay time is achieved
which is used for stopping motor if the fault is
not cleared after this delay time. The
characteristics of motor which is used for the
proposed system are listed in Table 1. The values
in Table 2 are used for preparing fuzzy rule base.
Limit values are selected in accordance with
NEMA standards and TS-3205 EN 60034-1
numbered standard of TSI (Turkish Standards
Institution).
Table I. Motor Parameters
Voltage : 230/380 V
Speed
: 1500 rpm
2.2kW induction
Current : 5.3A
motor
Torque : 16 Nm
Efficiency : 81%
Table II. Limiting Values
Parameters Min Set
Max
Value
Set
Value
Unit
Over Voltage
240
>270
V
Over Current
5.5
>8.4
A
Temperature
135
>155
˚c
Voltage
Unbalance
20
>50
V
Current
Unbalance
0.5
>2
A
Low Voltage
200
<160
V
Time
(Output)
0
4.5
Sec
Figure1. Fuzzy Control System
The two separate rule base are created by
dividing six different input values to reduce the
processing time and size of fuzzy system as
shown in figure 1. Here the fuzzy expressions
have three membership levels which are lowmedium-high. If six inputs are not divided in two
groups then the number of rules will be 36= 729.
By dividing the inputs, rules are reduced to 126.
Some samples of the rule base used in protection
system model are shown in the following Table
3 and Table 4. Where NA shows that this
particular error did not occurred in induction
motor.
TABLE-3.1ST Rule Base Sample
Rule Over
Over Temperature Time
No. voltage current
delay
1
2
3
4
5
6
7
8
9
10
OVL
OVL
OVL
OVL
OVM
OVH
OVL
OVL
NA
OVL
OCL
OCL
OCM
OCH
OCH
OCL
OCM
NA
OCL
NA
TL
TM
TH
TL
TH
TL
NA
TL
TL
NA
VL
VL
N
LN
VS
LN
LN
VL
VL
LN
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11
NA
OCM
NA
N
Table-4 2ND Rule Base Sample
Rul
e
No.
Voltage
Unbalan
ce
Current
Unbalan
ce
Low
Voltag
e
1
2
3
4
5
6
7
8
9
10
11
VUL
VUL
VUL
VUL
VUL
VUL
VUL
VUM
VUL
NA
VUL
CUL
CUL
CUL
CUM
CUM
CUM
CUH
CUM
NA
CUL
NA
LVL
LVM
LVH
LVL
LVM
LVH
LVL
NA
LVL
LVL
NA
Tim
e
Dela
y
VL
VL
LN
VL
LN
N
LN
N
VL
VL
LN
II.
Simulink model
Simulink model used in the paper is shown in the
figure 2. In the Simulink model of system block
function consists, Min–Max: Simulink blocks
for to get Minimum and maximum of input
values Mux: Simulink blocks to multiplex input
nodes of blocks that have one input
(Multiplexer) Fuzzy logic controller 1,2:
Simulink block includes fuzzy logic design. This
block calculates the time values and transfers it
to next block.
Figure 2. Simulink Model of the System
Display: shows the minimum one of the
calculated time periods.
Voltage-Current Unbalance: Compares input
values and give the biggest one of the differences
as result. To do this, three inputs are subtracted
from one another and the biggest absolute result
considered as the final value. Internal structure
of this block is given in figure3
Voltage 1-2-3: 3 phase supply voltage. Current
1-2-3: Input current of three phases
Temperature: Input for winding temperature of
motor.
Here, the figure 4 and 5 shows the membership
functions of the over voltage and output delay
time accordingly. For over voltage there are
three membership functions which are Over
Voltage Low (OVL), Over Voltage Medium
(OVM) and Over Voltage High (OVH).
Similarly, for the delay time 5 membership
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functions are Very Long (VL), Long (LN),
Normal (N), Short (s) and Very Short (VS).
Figure 3. Voltage Unbalance Block
Figure 4. Membership Function for Over
Voltage
Figure 5. Membership Function for Delay
Time
III.
SIMULATION RESULT
In this study, the fuzzy logic based flexible
protection system was implemented for
induction motor. The Simulink model was
developed for simulating the delay time for
different operating conditions. The input clusters
and fuzzy rule bases have been entered in to FIS
GUI, fuzzy logic toolbox of MATLAB. The
results are produced by using two rule base
which is given in Table 5 and 6.
TABLE5. Some Results for Rule Base 1.
Rul Over
Over Temperatu Dela
e
Voltag Curre
re
y
No.
e
nt
(˚c)
Tim
(V)
(A)
e
(s)
1
260.9
8.5
155.2
1.33
2
256.8
8.8
NA
2.26
3
246.6
NA
138.2
3.58
4
NA
8.6
155.5
1.27
5
278.4
NA
NA
2.25
6
NA
NA
153.8
1.65
TABLE6. Some Results for Rule Base 2.
Rul Voltage
Current
Low Dela
e
Unbalan Unbalan Voltag
y
No.
ce
ce
e
Tim
(V)
(A)
(V)
e
(s)
1
23.8
0.9
192.5 3.58
2
30.9
1.6
186.2 2.92
3
37.6
1.5
NA
2.45
4
NA
2.6
168.8
1.5
5
NA
NA
182.1 2.71
III. CONCLUSION
In this paper, a fuzzy logic-based protection
system is used for detecting the faulty operations
of three phase induction motor. A Simulink
model was implemented for protecting the motor
from over voltage, over current, low voltage,
current and voltage unbalance and temperature
rise. When any error is detected, the system
waits for certain time and then stops induction
motor if fault is not recovered. In mechanical
protection relays, this delay time was adjusted
manually but this proposed protection system
produces delay time according to fuzzy logic for
different degree of various error combinations.
So the flexible and optimal delay time is
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obtained and this methodology is accurate and
easy to implement.
REFERENCES
[1] O. Uyar and M. Çunkaş, 16-18 May 2011.
“Design of Fuzzy Logic Based Motor Protection
System”, In: 6th International Advanced
Technologies Symposium (IATS’11), Elazığ,
Turkey.
[2] Weidman Qi, a, Jie Xiao, and Youhan Deng,
2015.“Induction Motor Protection System
Based On Fuzzy Logic”, In: Applied Mechanics
and Materials Vols 719-720 (2015) pp 584589.Trans Tech Publications, Switzerland.
[3] Pedro Vicente Jove Rodríguez, 2008.
“Detection of Stator Winding Fault In Induction
Motor Using Fuzzy Logic”, Elsevier Science.
[4] Priyanka Nath, Jamini Das, Abdur Rohman,
Tapan Das, April 6-8, 2016. “A Fuzzy Logic
Based Overcurrent Protection System for
Induction Motor”,In: International Conference
on Communication and Signal Processing, India.
[5] Okan Uyar, Mehmet C¸ unkas, 2012. “Fuzzy
logic-based induction motor protection system”,
Springer-Verlag London.
[6] Mr. Chavan Mayur D, Mr. Swami P.S, Dr.
Thosar A.G, Mr. Gharase Rajendra B., Dec
2013. “Fault Detection of Induction Motor
Using Fuzzy Logic”, In: International Journal of
Engineering Research & Technology (IJERT).
ISSN: 2278-0181.
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A Review Paper on Fuzzy Logic Based Speed Control of
Induction Motor
Vishal R. Patel, Akshay A. Pandya
Department of electrical engineering, BVM Vallabh Vidhyanagar Gujarat, India
Corresponding Author: vrp1694@gmail.com
Abstract:
Induction motors are designed to work for constant speed application, many industrial applications
require wide range of speed control of induction motor. Fuzzy logic-based speed controller for induction
motor provides large range of speed control compared to conventional controllers. This paper presents
the study of Fuzzy logic-based speed controller for induction motor. Error signal and change of error
signals are the two inputs to Fuzzy logic controller, which performs 49 if-then rules inference on that
signals and generates control signals which are fed to inverters. The control signals obtained from fuzzy
logic controller (FLC) drives the GATE pulses of inverter which indeed changes the output voltage of
the inverter according to change in speed. The results obtained from this approach are compared with
conventional controller like PI controllers.
Keywords: Induction motor, Fuzzy logic controller, Inverter
1.
Introduction
Induction motors have gained popularity in
industrial applications due to their low
maintenance, robust construction, high starting
torque and cost effectiveness. Induction motors
are designed to have constant speed. But in some
cases their speed needs to be controlled. Such
cases are (1) when the induction motor is started
with no-load; at the time of starting it draws
more current from supply which is 6-7 times
higher than the rated current. Since no load is
connected to motor it runs at very dangerous
speed which may damage the motor. (2) In some
situation the motor needs to drive the load whose
speed may be greater than or less than the rated
speed of induction motor. So, in these situations
instead of installing a new machine it is better to
control the speed of existing machine.
The speed of induction motor can be controlled
from stator side as well as from rotor side. Most
common methods used for speed control are V/F
control and vector control method. These
methods are implemented using controllers in
industries. The most popular controller among
all industries is PI controller, because they are
easy to design and their low cost. The only
problem associated with PI controller is that the
design complexity increases with non-linearity
of Induction motor. Hence non-conventional
controller like Fuzzy logic controller can be used
to overcome this problem.
2.
Fuzzy logic control
After the discovery of fuzzy set theory by L.
Zadeh in 1965, it has gained popularity in last 3
decades. In first few years, it was just a
theoretical concept but in recent years engineers
have started to use this approach in real word
application. Fuzzy logic controllers follow the
fuzzy set theory and it has three basic functions
which are as follows…
(1) Fuzzification: The fuzzification module
converts the crisp values of the control inputs
into fuzzy values, so that they are compatible
with the fuzzy set representation in the rule base.
(2) Rule base: The rule base is essentially
the control strategy of the system. It is usually
obtained from expert knowledge or heuristics
and expressed as a set of IF-THEN rules. The
rules are based on the fuzzy inference concept
and the antecedents and consequents are
associated with linguistic variables.
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(3)
Defuzzification:
The mathematical
procedure of converting fuzzy values into crisp
values is known as ‘Defuzzification’. There are
four methods are available for defuzzification.
However, the choice of defuzzification depends
upon the application and available processing
power.
3. Fuzzy logic controller in MATLAB
MATLAB provides users with built in function
of Fuzzy logic controller. It can be accessed by
using the command “fuzzy” in command
window. The fuzzy logic controller window
consists of input block, output block and
controller block as shown in the following figure
1. Designer may choose more than one input and
more than one output at the same time. The input
and output blocks consist of membership
functions of the given system. The designer may
choose from various membership functions
depending upon his needs, however most
commonly used membership functions are
Triangular and Trapezoidal membership
function. The rule base of the controller consists
of number of IF-THEN rules, which are
designed according to inputs and outputs of the
system. The rules designed in controller are in
linguistic form; hence, it is easy for any operator
to understand.
Figure 1: Fuzzy logic controller editing window
4.
Simulation for the proposed scheme
The speed control of induction motor using
fuzzy logic controller can be simulated using
MATLAB software. Whole simulation process
can be divided into following blocks.
(1)
Fuzzy logic controller: Basic function of
the fuzzy logic controller in this particular
scheme is to generate current reference signals,
which drives the inverter, and hence the input
voltage to the motor can be changed according
to speed of the motor. There are two inputs to the
fuzzy logic controller. One is error in speed,
Table 1: output table of fuzzy logic controller
which can be obtained by comparing the actual
rotor speed with that of reference speed; another
input is change in error. There are 7 membership
functions for both speed error and change in
speed error, hence total of 49 IF-THEN rules
needs to be designed in controller block. The
output table for the FLC is shown in figure.
(2)
Driver circuit for inverter: The current
reference generated by the fuzzy logic controller
are converted from d-q to α-β quantities using
inverse Park transformation. This driver circuit
generates the GATE pulses, which drives the
inverter switches.
(3)
Inverter circuit: It consist of six power
electronic switches such as IGBT, MOSFET etc.
connected in bridge form. The driver circuit
governs the sequential switching of the power
electronic switches. The output voltage of the
inverter is fed to induction motor.
(4)
Induction motor: For the means of
simplicity, the induction motor is modeled in
mathematical
form.
The
dynamic
(mathematical) model of induction motor consist
of electrical sub model and mechanical sub
model. The dynamic model of induction motor
is shown in following fig.2.
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Rotor leakage inductance
0.002
Mutual inductance
0.041
Inertia
0.089
Number of poles
4
Table 2: induction motor parameter
A 3-phase, squirrel cage, 5hp, 1500 rpm
induction motor is used for the simulation.
Whole control strategy for the speed control of
induction motor can be simulated as shown in
the block diagram. The simulation results
obtained by the fuzzy logic controller can be
compared with conventional PI controller.
Research says that overshoot problem arising in
using PI controller for speed control of induction
motor can be overcome by using Fuzzy logic
controller.
The dynamic (mathematical) model of induction
motor is designed with following parameters.
Parameter
Value
Stator resistance (Rs)
0.435
Rotor resistance (Rr)
0.816
Stator inductance
0.0424
Rotor inductance
0.0417
Stator leakage inductance
0.002
5.
Conclusion
Fuzzy logic approach can be used to implement
human thought process in real world application.
Fuzzy logic controllers are easy to design and
they provide wide range of control for linear and
non-linear systems. The fuzzy logic controller
used for speed control of induction motor
removes the overshoot problems and gives better
results compared to PI controller for the same
system. In early years the fuzzy logic was just a
theoretical concept, but now it is possible to
implement these controllers to work in real word
applications.
References
(1) Neural and Fuzzy Logic Control of Drives
and Power Systems
(2) P.Tripura and Y.Srinivasa Kishore Babu
2011. Fuzzy Logic Speed Control of Three
Phase Induction Motor Drive
(3) Dr T.govindaraj, G.divya 2014. Speed
Control of Induction Motor Using Fuzzy
Logic Control
(4) V.Vengatesan, M.Chindamani 2014. Speed
Control of Three Phase Induction Motor
Using Fuzzy Logic Controller by Space
Vector Modulation Technique
(5) K. L. SHI, T. F. CHAN, Y. K. WONG and
S. L. HO 1999. Modelling and simulation of
the three-phase induction motor using
Simulink
(6) S. Senthilkumar and S. Vijayan 2013.
Simulation of High Performance PID
Controller for Induction Motor Speed
Control with Mathematical Modeling
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(7) V. Chitra, and R. S. Prabhakar 2006.
Induction Motor Speed Control using Fuzzy
Logic Controller
(8) Atul M. Gajare, Nitin R. Bhasme 2012. A
Review on Speed Control Techniques of
Single Phase Induction Motor
(9) Divya Asija 2010. Speed Control of
Induction Motor Using Fuzzy-PI Controller
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Renewable Energy Resources with Internet of Things
Himanshu Swarnkar, Shiv Lal
Government Engineering College Banswara, India 327001
Corrrespondig Author: himanshu.swarnkar23@gmail.com
Abstract:
This paper introduces the new way of using the internet of Things in renewable energy resources in smart
city like smart buildings, smart hospital, smart traffic, smart factories and transportations. All of above
smart services are expected to run without any interruptions by using help of smart energy and electrical
power grid. To maintain the services of smart cities run without interruption Internet of Things and cloud
computing are very important in such transfers. The paper presents the role of Internet of Things (IoT)
in renewable energy resources association in electricity grid.
Key words: Internet of Things, Smart Grid, Cloud Computing HAN, BAN, IAN.
I.
INTRODUCTION
The traditional host of World Wide Web text,
pictures, audio, and video are incorporating to the
physical host that providing user to control
physical objects. Home Things, remote CCTV
cameras floors of factory are monitors and
controlled suing the Internet of Things (IoT) as
media of communication. The physical web is
concept is adapting nowadays. For example, to
control energy in buildings an internet of Things
are use [1]. This paper in introduce the IoT based
experimental prototype which save the energy and
provide the positive impact. For communication
between consumers and utility command points to
exchanges energy and electrical consumption,
smart meters are use [2]. This paper extended to
smart gas meters and smart water meters. In this
paper we provide the guideline for utilization of
smart meters in smart energy monitoring and
control systems. Figure 1 shows the wide image
of how power and energy from an essential part of
smart cities [3]. .
As illustrates in [3] real time operation data
from different objects like smart electricity,
water and gas meters, smart surveillance, smart
transportation, smart waste management and
smart environment systems are collected. After it
the data is provided to a smart cluster Head
(SCH) and then transmits this data to local smart
fusion nodes (SFN). As a result, IoT based smart
decision is taken and control enabler center
collects and interchange the data for monitoring
and controlling this architecture [3].
A smart grid having mainly three layers, which
are system of systems, communication networks
and applications, layers [4-8]. Many literatures
illustrate the popular renewable energy resources
are solar energy, wind energy and hydroelectric
energy [6-9].
II.
Mechanism of Internet of Things
Nowadays this world is moving to more
interconnectivity and more conductivity. It has
become an integrated global community using
multiple technologies and various area of
applications and services. IoT concepts are
moving to a word where real, digital and
imaginary thing are converging to makes our
cities smarter and more intelligent. Traditional
web technology is empowered by IoT to connect
physical objects (Things) such as home
appliances and smart grid Things with a unique
address form each device [10-11]. This has been
possible by using the IPV6 protocol which has
2128 IP address as compared to IPv4 protocol
which contains 232 IP addresses. By using IPV6
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billions of Things are connected, monitored and
controlled at the same time [12-14].
Due to popularity of IoT nowadays,
professional of industrial and academics are
divided it into two part or categories one is
Consumer Internet of Things (CIoT, also IoT) and
Industrial Internet of Things (IIoT) [15-16]. The
most popular application are smart phones,
wearable, TVs and appliances and most popular
IIoT applications are smart factories, grids,
machines, cities and cars. Following figure shows
IoT and IIoT popular application.
III.
Propose Protocol
Consumption Domain is one of the domains of
National Institute of Standard and Technology
(NIST)
smart
gird
conceptual
model.
Consumption domain is essential and primary
candidate for agglomeration and installation of
renewable energy resources. As illustrate in
figure 3, mainly three types of consumers, which
are residential, commercial and industrial. For all
type of consumer renewable energy resources
such solar, wind and hydro are installed. The
consumption domain is divided into three
different type of networks: Home Area Network
(HAN), Business Area Network (BAN) and
Industrial area network (IAN) [18-19].
Fig.1. The implementation concept of architecture in
smart cities [3]
Fig.3. Consumers with multiple network protocol
[18]
Fig.2. Categories of Internet of Things [14]
In this network so many communication
protocols are utilizing such as ZigBee, PLC, ZWave, WiFi, WiMax, 3G/GSM and LET. The
figure number 3 represent the protocols of
communication networks which use at the same
time within one gird [19]. As we already mention
in section II, there are two categories IoT and
IIoT. This paper proposes the way of using the
single network protocol to utilization of both to
integrate three different consumer communication
networks to the smart grid networks.
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The resources of renewable energy is
considered as an object and each object is the
smart grid network unique IP is assigned. To
monitor each object, bidirectional communication
is use as control is done via its unique IP address.
This proposes protocol eliminates the need
multiple communication protocol in the same
grid.
This paper proposes an IoT/IIoT conceptual
model to integrate renewable energy resources
with one common network protocol instead of
using the multiple protocol.
Different from the use of multiple
communication protocol in the consumer
communication network this paper introduce the
use of single communication protocol by
assigning the unique IP address to each electric
grid devices as an object based on IoT. Using of
single protocol is providing more reliable and
scalable network which can control and manage
remotely with the help of Internet.
V.FUTURE WORK
The propose prototype is work on consumption
domain but it is also extends on distribution and
generations domains of energy.
REFERENCES
Fig.4. Propose Consumers Network with one
network protocol utilizing Based on IoT concept.
Communication protocol 6LowPAN is use to
utilize IP protocol, which is based on IPv6. This
communication protocol has 127 bytes frame size
which proved more space for a payload of 65-75
bytes [14]. The use of 6LowPAN communication
protocol, make the network faster and scalable.
Scalable feature enable the networks to add more
devices and appliances such as local batteries,
smart meters and home appliance, in the existing
network as an object and each object have unique
IP address. With this unique IP address of each
object we control and monitor remotely using the
internet.
Furthermore, same can be extended to adding
more other devices such as circuit breaker,
capacitor banks, relays and phase measurements
units of electricity grid.
IV.
CONCLUSIONS
[1] Jianli Pan, Rajjain Sudharthi paul; Tam Vu;
Abusaueed Saifullah;, Mo Sha, an Internet of
Things Framework for Smart Energy in
Building: Designs,
Prototype and
experiments, IEEE Internet of Things
Journal,2015 :vol. 2, no. 6 p. 527-538.
[2] Qie Sun: Hailong Li; Zhanyu Ma; Chao Wang;
Javier Campillo; Qi Zhang; Fredril Wallin;
Jun Guo, A Comprehensive Review of Smart
Energy Meters in
Intelligent Energy
Network, IEEE Internet of Things Journal
2015: Vol. 3 No. 4, p. 4464-479
[3] Satyanarayana V. Nandury; Begum, Smart
WSN-based ubiquitous architecture for smart
cities, 2015 International Conference on
Advances In Computing, Communications
and Informatics, 2015: p. 2366-2373.
[4] T. Adefarati; R. C. Bansal, Integration of
renewable distributed generators into the
distribution system: a review, IET Renewable
Power Generation, 2016, Vol. 10, No. 7, p.
873- 884.
[5] Ma Yiwei; Yang Ping; Guo Hongxia; Zeng
Jun, Development of distributed generation
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system based on various renewable energy
resources, 4th International Conference on
Power
Electronics
System
and
Application(PES), 2011, p. 1-5.
[6] Wencong Si; Jianhui wang; Jaehyung Roh,
Stochastic Energy Scheduling in Microgrids
with Intermittent Renewable Energy
Resources IEEE Transactions on Smart Grid
2014; Vol. 5 No. 4 p. 1876-1883.
[7] S. Surender Reddy, P.R. Bijwe, Day-Ahead
and Real Time Optimal Power Flow
considering Renewable Energy Resources,
International Journal of Electrical Power and
Energy Systems, 2016; Vol. 82, No 11., p.
400-408.
[8] Abraham Debebe woldeyohannnes, Dereje
Engida woldemichael, Aklilu Tesfamichael
Baheta, Sustainable renewable energy
resources utilization in rural areas,
Renewable and Sustainable Energy Reviews,
2016: Vol. 66, No. 12. P. 1-9.
[9] Aras Ahmadi, Ligia Tiruta-Barna, Enrico
Benetto, Florin
Capitanescu, Antonino
Marvuglia, On the importance of
intergratomg alttternative renewable energy
reeesources and their life sycle networks in
the eco design of conventional drinking water
plants, Journal of Cleaner Production 2016:
Vol. 135, No 11, p. 872-883.
[10] Mohsen Hallaj Asghar; Atul Negi; Nasibeh
Mohammandzadeh, Principla application and
vision in Internet of Things(IoT),
International Conference on Computing,
Communication and Automation, 2015: p.
427-431.
[11] Steven E. Collier, the Emerging Internet:
Convergence of the Smart Grid with the
Internet of Things, IEEE Rural Electric
Power Conference, 2015: p. 65-68.
[12] John Pickard; Annie Y. Partick; Andrew
Robinson, Analysis of enterprise IPv6
readiness, southeast Conference 2015, year
2015 Pages 1-7.
[13] Jonghwan Hyun; Jian Li; Hwankuk Kin; Jae
Hyoung Yoo; James won-ki Hong, IPv4 and
IPv6 performance comparison in IPv6 LTE
network,
the
Asia-Pacigic
Network
Operations and Management Symposium,
2015, p. 45-150.
[14] Gonnot, T. and Saniie, J., User Defined
Interaction between Devices on 6LowPAN
Network for Home Automation. IEEE
International of Technology Management
Conference, 2014: P. 1-4.
[15] Designing the Industrial Internet of Things,
http://
electronicdesign.com/industrial/designinginsustrial-internet-things, Accessed 30 July,
2016.
[16] Hisashi Sasajima; Toru Ishikuma; Hisanori
Hayashi, Future IIOT in process automationLatest trends of standardization in industrial
automation , IEC/TC65, 54th Annual
Conference of the society of Instument and
Control EnGineers of Japa (SICE), 2015: p.
963-967.
[17] National Institute of Standard and
Technology. NIST framework and roadmap
for smart grid interoperability standard,
release
1.0,
http://
www.nist.gov/public_affairs/releases/upload
/smartgird_interoperability_final.pdf.
January 2010.
[18] B. Al-Omar, AR Al-Ali, R Ajmed, T
Landosli, Role of information and
communication technologies in the smart
dtid, Journal of Emerging Trends in
Computing and Information Science, 2012,
Vol. 3, No. 5,p. 707-716.
[19] Ye Yan; Yi Qian; Hamid Sharif; David
Tipper, A Survey on Smart Grid
Communication Infrastructures: Motivations,
Requirements and challenges, IEEE
Communications Survey and Tutorials, 2013:
Vol. 15, No. 1, p. 5-20.
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Renewable Energy Options and Possibilities to develop Banswara as
Energy Hub: A theoretical approach
Shiv Lal, Shulbha Kothari
Government Engineering College Banswara
Corresponding Author: shivlal1@gmail.com
Abstract
Energy production from renewable energy option is a sustainable approach. The manuscript is
presenting the Banswara can become a renewable Energy Hub for India. Therefore, research in the
field of solar, wind, biodiesel, micro-hydel and algae area can be done as resource area and for
implementing the all renewables in Banswara division.
the most efficient PV cell today has less than
50% electricity conversion efficiency. [3]. The
1.
Introduction
working efficiency of PV cell is depending
The energy is the primary need of human being
and the high-grade energy (Electrical Energy) is
upon the weather quality, number of clear sky
being utilized for many household and
days, atmospheric temperature, humidity and
industrial applications. Conventional and nonwind speed also.
conventional methods are two methods by
India is ready for biodiesel revolution. As per
which energy can produced. The coal based
the [4] government of India is working on
thermal power plants are the major contributers
nationalized biodiesel mission. India shall be
of conventional energy (approximately 68% of
produced biodiesel at commercial stage on or
total energy production). The conventional
before the end of 2006; one biodiesel plant is
energy resources like coal, diesel, petrol etc. are
ready for production situated at Nalgonda in
limited and will be vanished in next few years.
Andhra Pradesh state.
The renewable energy is the sustainable option
The aim of the above given mission is that the
for electrical energy production and whole
use of 20% blended biodiesel (B20 means 20%
world is continuously working on to increasing
biodiesel and 80%diesel) will be started on
the production percentage though RES. The
commercial stage till 2011-12. The government
sustainable development of the human society
will be saved the sum of Rs20, 000 crores and
is directly linked with the renewable energy
gives the employment to atleast 2 crore peoples.
options. [1]
A minimum wind which required for the power
Table 1: Acquiring land for agriculture of
generation is available in the region of
Jatrofa [4]
Banswara.), 750kW and 1 MW wind mills are
S.NO. STATE
AREA
(in
situated in wind farms of India. The wind
Hectare)
energy power generation mills are available in
1
Rajasthan
275
various design features according to the number
of blades, power generation capacity, implant
2
Madhya Pradesh
260
according to the wind flow available, shaft
3
Gujarat
240
alignment and design of blades. [2]
4
Utter Pradesh
200
A photovoltaic cell is use to convert solar
irradiance in to electricity. The best temperature
5
Chhattisgarh
190
for generation of electricity is 15-35 degree
6
Maharastra
150
Celsius. Temperature more than 40 degree
Celsius is not utilized for power generation,
7
Harayana
140
causing a decrease in their efficiencies. Even
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Today the action plan of India is targeted on Jatrofa
because its research is likely to be completed. So
many oils can be used for manufacturing (blending)
biodiesel, Thumba oil is one of the oil which found
in western Rajasthan (India) and which is very
familiar to use in soap manufacturing. Another
important seed oil produced in abundant quantity in
India are Soya oil, Sunflower oil, Mustered oil, Rice
oil, Jatropha oil, Ratanjot oil, Thumba oil, Rapeseed
oil, etc. The biodiesel can also be produced from
algae and so many researchers have worked on
algae. [5-11]
There are 112 lakes in this area and the area is hilly
so the possibility of micro-hydel power plants.
Almost the whole area is irrigated by canals. The
mahi dam is Third Biggest Dam in India. Various
designs of hydro-power generation plants are
accessible in the market. So the selection of the
micro-hydel power plant. [12-16]
This manuscript is presented the scope and
feasibility of renewable energy sources in
Banswara. Because Banswara is a lush green region
and abundant of water is found in the same area.
Banswara is known as cherapunji of Rajasthan.
2.
2.1
Fig. 1. Geographical map of India
Fig. 2 Geographical map of Banswara [google
earth]
It has more than 112lakes and so many small
islands are situated between the lakes, thatswhy
it is called as city of hundred islands. One of
the example of bunch of islands is called
“Chachakota” It is sited at backside of Mahi
Dam which is shown in different views in Fig.
3[17]
Material and Methods
About Banswara
Banswara is a district is situated between
23.11° N to 23.56° N latitudes and 73.58° E to
74.49° E. longitudes in Rajasthan state of India.
Fig. 1-2shows the geographical view of
Banwara on the google earth map. The state of
Banswara was founded by Maharawal Jagmal
Singh. And It is named for the "bans"
or bamboo forests in the area. [17]
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Banswara city is governed by City Council
(Nagar Parishad) which comes under Banswara
Urban Agglomeration. The city has population
of 100,128, its urban / metropolitan population
is 101,177 of which 51,941 are males and
49,236 are females. [www.wikipedia.org] . The
Banswara is situated at southern region of
Rajasthan and its area is 5037 square kilometers
and located between 23.11° N to 23.56° N
latitudes and 73.58° E to 74.49° E. longitudes.
The climate of Banswara is milder than the
desert regions in further north and north-west.
Maximum temperature is 45 degrees
Celsius to 46 degrees Celsius.
Minimum temperature is 10 degrees
Celsius to 20 degrees Celsius
Normal annual rainfall is 922.4 mm
The main tourist places in Banswara are as
follows: Andheswar Parshwanathji, Anekant
Bahubali Temple, Abdullah Pir, Anand Sagar
Lake, Arthuna Temples, Dailab Lake,
Madareshwar Temple, Mahi Dam, Mangarh
Hill, Parheada Temple, Bhim kund, Talwada,
Mata Tripura Sundari Tample, Kagdi Pick-up
weirs. The total transformer capacity in the
district is 63.1 MV·A. of the 1,431 villages
1,219 villages were electrified up to 31 March
2000.
2.2
Power
generation
from
Renewable Resources in Banswara
Region
2.2.1 Wind Power Generation
The India is producing thousands of MW
energy from wind. The table 2 shows the global
wind power generation and 18,212.6 MW
power is generated or project under
construction in India and the official capacity as
on 2016 is 28,279.0 MW. [18]. According to
the below table, India is in the third number for
wind power generation (operational and under
construction plants)
Table 2. List of countries included for wind
power generation [18]
Fig. 3. Chachakota at Banswara[17]
Country
Database capacity Official capacity
(MW)
(MW)
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Operational or
WWEA values
under construction
Albania
150.0
42.0 (2016)
Algeria
10.2
10.2 (2016)
Argentina
1,121.5
279.0 (2016)
Armenia
2.6
2.6 (2016)
Australia
6,363.0
4,326.0 (2016)
Austria
2,551.5
2,632.0 (2016)
Azerbaijan
54.9
2.2 (2016)
Bangladesh
0.9
1.9 (2016)
Belarus
3.4
3.4 (2016)
Belgium
2,927.8
2,386.0 (2016)
Bolivia
27.0
27.0 (2016)
Brazil
12,769.9
10,800.0 (2016)
Bulgaria
637.5
691.0 (2016)
Canada
12,782.7
11,898.0 (2016)
Cape Verde
27.9
25.5 (2016)
Chad
1.1
0.0 (2016)
Chile
1,998.1
1,424.0 (2016)
China
120,560.1
168,730.0 (2016)
Colombia
19.5
19.5 (2016)
Costa Rica
347.4
297.0 (2016)
Croatia
466.0
467.0 (2016)
Cuba
11.7
11.7 (2016)
Curaçao
32.3
15.0 (2016)
Cyprus
126.7
158.0 (2016)
Czech Republic 347.9
282.0 (2016)
Denmark
5,841.4
5,227.0 (2016)
Dominican
280.3
135.0 (2016)
Republic
Ecuador
76.9
19.0 (2016)
Egypt
744.8
810.0 (2016)
Eritrea
0.8
0.8 (2016)
Estonia
409.9
310.0 (2016)
Ethiopia
324.2
324.0 (2016)
Faroe Islands 18.6
18.3 (2016)
Fiji
10.2
10.0 (2016)
Finland
2,051.9
1,539.0 (2016)
France
13,019.9
12,065.0 (2016)
Gambia
0.2
0.2 (2016)
Georgia
20.7
20.7 (2016)
Germany
Greece
Grenada
Guam
Guatemala
Guyana
Honduras
Hungary
Iceland
India
Indonesia
Iran
Ireland
Israel
Italy
Jamaica
Japan
Jordan
Kazakhstan
Kenya
Latvia
Libya
Lithuania
Luxembourg
Macedonia
Mauritania
Mauritius
Mexico
Mongolia
Montenegro
Morocco
Mozambique
Namibia
Netherlands
New-Zealand
Nicaragua
Nigeria
Norway
Pakistan
Panama
Peru
49,213.2
2,648.0
1.3
0.3
73.8
0.0
179.9
536.6
4.2
18,212.6
75.0
146.8
3,206.0
27.3
9,671.5
102.2
2,730.0
322.2
45.1
335.8
53.1
20.0
379.9
127.4
36.9
136.8
10.5
5,090.1
100.1
72.0
1,308.6
0.3
5.2
4,748.0
691.1
186.2
10.2
2,291.6
487.2
495.0
372.4
50,019.0 (2016)
2,374.0 (2016)
0.7 (2016)
0.3 (2016)
76.0 (2016)
13.5 (2016)
176.0 (2016)
329.0 (2016)
3.0 (2016)
28,279.0 (2016)
1.4 (2016)
118.0 (2016)
2,830.0 (2016)
6.0 (2016)
9,257.0 (2016)
72.0 (2016)
3,234.0 (2016)
119.0 (2016)
2.0 (2016)
25.5 (2016)
68.0 (2016)
20.0 (2016)
493.0 (2016)
99.0 (2016)
37.0 (2016)
34.4 (2016)
10.5 (2016)
3,709.0 (2016)
50.9 (2016)
0.0 (2016)
795.0 (2016)
0.3 (2016)
0.2 (2016)
4,328.0 (2016)
623.0 (2016)
186.0 (2016)
13.4 (2016)
873.0 (2015)
591.0 (2016)
270.0 (2016)
245.0 (2016)
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Philippines
Poland
Portugal
Puerto Rico
Romania
Russia
Saint Kitts and
Nevis
Saudi Arabia
Serbia
Seychelles
Slovakia
Slovenia
South Africa
South Korea
Spain
Sri Lanka
Sweden
Switzerland
Taiwan
Tanzania
Thailand
Tunisia
Turkey
Ukraine
United Arab
Emirates
UnitedKingdom
Uruguay
USA
Vanuatu
Venezuela
372.9
5,709.0
5,372.0
125.9
3,651.0
99.3
216.0 (2016)
5,782.0 (2016)
5,316.0 (2016)
125.0 (2016)
3,028.0 (2016)
16.8 (2016)
2.2
2.2 (2016)
2.8
9.9
6.0
3.1
5.5
2,322.2
874.2
23,348.9
129.9
6,113.9
75.1
641.0
50.0
596.3
242.4
7,303.6
939.4
0.0 (2016)
10.0 (2016)
6.0 (2016)
3.0 (2016)
3.0 (2016)
1,471.0 (2016)
1,031.0 (2016)
23,020.0 (2016)
130.0 (2016)
6,493.0 (2016)
75.1 (2016)
682.0 (2016)
0.0 (2016)
223.0 (2016)
245.0 (2016)
6,081.0 (2016)
559.0 (2016)
0.9
0.9 (2016)
22,119.0
14,512.0 (2016)
1,502.8
98,431.0
3.9
175.9
1,210.0 (2016)
82,033.0 (2016)
3.0 (2016)
30.0 (2016)
The Deogarh, Pratapgarh wind energy project
of 126 MW is commissioned by Welspun
renewables. generate 290 million units of clean
energy and help mitigate 2,11,922 tonnes of
carbon emissions annually. The company
claims that 7,25,760 homes will get access to
clean green energy, replacing the need to source
carbon based energy generation. [19]
It was established jointly by the Rajasthan
Energy Development Agency (REDA) and the
Rajasthan State Power Corporation. The
Rajasthan State Electricity Board (RSEB) has
signed a power purchase agreement with the
State Power Corporation to buy power at the
rate of Rs. 3.03 per unit. [20]. The Mahi basin
is most suitable region for wind power
generation which includes Pratapgarh, Ghatol,
Kushalgarh and Ratlam Road in Banswara
Division. Fig. 4 (b) Shows the typical wind mill
of three blades situated in Pratagarh.
(a)
(b)
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(c)
(d)
(e)
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(f)
Fig. 4. Renewable Energy Options for
Banswara (a) Solar, (b) Wind, (c) Micro-hydel,
(d) Biomass, (e) Algae, (f) Bio-diesel from
different resources
2.2.2 Biomass and Biodiesel Power
Plant
Among the different renewable energy sources,
biomass is a versatile energy source. Rajasthan
is fast catching up for tapping biomass energy.
'Policy for Promoting Generation of Electricity
from Biomass 2010' had been issued for
encouraging investments in the sector. Biomass
based power projects with capacity of
106.3MW have been commissioned as on
31.12.2011. [21]. A 6 MW biomass power plant
is also under execution in Banswara. [22]. The
largest production of algae and biodiesel seeds
in this area and we can increase the production
of biodiesel plants in Banswara by plantation in
the area where barren lands available.
2.2.3 Power from solar Energy
A typical solar cell is shown in fig. 4. (a), It can
be utilized to generate the electricity from solar
energy and that produced energy can be utilized
in both off-grid and grid connected
applications. Banswara is a clean weather
region having lush green forest. It has
approximately 300 clear sky days. There is no
pollution means the maintenance cost related to
cleaning of cells is minimum, and the
temperature range between 10 to 45°C which is
most suitable for PV cells. The depth of
underground water is varying between 10 feet
to 100 feet. Solar PV pumps can be utilized for
agriculture for this region.
The area is tribal area and conventional
electricity is far from many villages so
decentralized off-grid PV system can be
utilized for many applications in this area.
Thousand of MW electricity can be produced
by solar PV farms implementation in this area
because many thousands of areas is converted
to barren lands in the Kushalgarh area.
2.2.4 Micro-hydel power plants
The possibility of micro-hydel power plant is
very high in Banswara. [23]. Table 3. Shows
the Mahi hydel power station. It is a major
hydel generating station under Rajasthan
Vidhut Utpadan Nigam (RVUN’s). The
generation capacity of Mahi Hydro-power
generation station is 140 MW.
Mahi Power House-I
(2x25MW)
FRL 281.5M(923ft.)
Live storage capacity
65.45TMCuft
Mahi Power House II (2 x 45MW)
Up Stream reservoir
level 220.5M(723.5ft)
Live storage capacity
1.53Million
cubic(54.4MCft)
Table 3. Mahi Hydel Power Station is RVUN's major
Hydel generating station situated on river Mahi near
Banswara town, comprising of 2 phases of installed
capacity 140MW.
Unit
Cost(Rs. Synchronising
Stage
Capacity(MW)
No.
Crore) Date
I
1
25
22.1.1986
68
II
2
25
6.2.1986
1
45
15.2.1989
119
2
45
17.9.1989
Table 4. shows the unit-wise generation in MU
from 2007-08 to 2012-13 session. The
generation in 2012-13 was observed higher than
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other session.
Table 4. Generation Status of Majer Hydel
Station
Generation in MU
Installe
Name of d
S.N
2012- 20112008- 2007Power Capacit
2010-11 2009-10
o
13
12
09
08
Plant
y in
MW
i) Mahi-I
Unit-I
25
60.773 58.083 33.427 34.759 44.984 93.451
50
25.4778 28.9011
Unit-II 25
96.398 74.016
33.293 95.095
83
17
Gross
157.17 132..09 58.9048 63.6601
188.54
Generati
78.277
1
9
83
17
6
on
ii) Mahi-II
26.977
19.843 45.679
Unit-I 45
26.13 6.3258 10.7886
8
8
2
90
20.028 22.269
49.073
Unit-II 45
4.0248 10.7388 15.36
6
6
4
Gross
47.006 48.399
35.203 94.752
Generati
10.3506 21.5274
4
6
8
6
on
MC
1.5
-II
MC
1.5
-III
Annoopga MC
ii)
1.5
rh PH-II -I
MC
1.5
-II
MC
1.5
-III
Suratgarh MC
iii)
2
MMH
-I
MC
2
-II
Pugal PHMC
iv) I P/S RD1.5
-I
620
Pugal PHMC
v) II P/S
0.65
-I
Dandi
MC
vi) Birsalpur
0.535
-I
Charanwa MC
vii)
1.2
la
-I
MC
viii) Mangrol
2
-I
MC
2
-II
MC
2
-III
Ghatol
MC
ix) RMC-I
0.4
-I
Mahi
MC
0.4
-II
Ganora
MC
x) RMC0.165
-I
II mahi
Total
168228
986880
0
445440 0
0
0
279426
302940
0
0
0
110040
747850
0
0
0
0
0
409243 0
281578 135330
35100
0
141690
974250
0
123105
898050
0
947400 0
306304 449232
0.6237 0.2248
6
32
472784 690497
0.4085 0.7403
6
36
172704 114160
0.1793 0.2290
28
24
109624 567718
43
9
Table 6. Generation Status of Major Hydel
Fig.5. Hydro power plant and main gate
opening of Mahi Dam
Fig.5 presented the photographic view of Mahi
Hydro power generation station at the Dam. In
regards of hydro-power generation, table 5 and
6 shows the power generation in the Rajasthan
in the year of 2010-11, 2011-12 and 2012-13.
Table. 5. Generation Status of MMH Power Station
of RVUN
Name of
S.N
Power
o
Houses
i)
20092011- 2012Rating(M 2010-11 10
12
13
W)
(KWH) (KWH
(KWH) (KWH)
)
Annoopga MC
1.5
rh PH-I -I
0
450000
Station
Generation in LU
Installe
Name of d
S.N
Power Capacit 2012-13 2011-12 2010-11 2009-10
o
Plant
y in
MW
i) RPS.
Total
Unit-I
43
698.406 558.090 173.808 157.680
1277.22
Unit-II 43
714.516
455.404 264.042
6
172
Unit-III 43
1111.448 974.526 693.276 483.954
Unit-IV 43
1135.956 825.756 421.872 533.058
Gross
3635.59
Generatio
3660.366
1743.996 1438.734
8
n
ii) J.S.
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Unit-I
33
Unit-II
33
99
Unit-III 33
Gross
Generatio
n
iii) Mahi-I
Unit-I
25
Unit-II
25
1114.350 889.500
536.600 342.300
0
0
1025.950
939.450 292.100 264.900
0
610.6000 946.050 634.550 565.100
2750.900 2775.00
1463.250 1172.300
0
0
50
Gross
Generatio
n
iv) Mahi-II
Unit-I
45
90
Unit-II 45
Gross
Generatio
n
3.
33.427 34.759
25.47788 28.90111
3
7
58.90488 63.66011
3
7
6.3258
4.0248
10.7886
10.7388
10.3506 21.5274
Conclusions
Banswara is situated at the south of Rajasthan
state and it is a highest rainy area,
approximately 300 clear sky days are observed
in 2016-17 and pollution free environment are
the major criteria for possibility of renewable
energy sources. It is found that all types
resources like solar, wind, water, bio-fuel are
available and it is most suitable area and can be
convert as power hub. Therefore, industrial area
can be expanded and it increased the
employment in present era.
Reference:
1. Shiv Lal, S.C. Kaushik, Ranjana Hans.
Experimental investigation and CFD
simulation studies of a laboratory scale
solar chimney for power generation.
Sustainable Energy Technologies and
Assessments 13 (2016) 13–22. DOI:
10.1016/j.seta.2015.11.005.
2. A. Al-Alili, Y. Hwang, R. Radermacher, I.
Kubo. A high efficiency solar air
conditioner
using
concentrating
photovoltaic/thermal collectors. Applied
Energy xxx (2011) xxx–xxx DOI:
10.1016/j.apenergy.2011.05.010
3.
Dainik Bhasker editor, 2005 “Biodiesel Rojgar
Bhara Iendhan” Page 1&12 Dainik Bhaskar
Newspaper October 23,
M. Faried, M. Samer, E. Abdelsalam, R. S.
Yousef, Y.A. Attia, A. S. Ali, Biodiesel
production from microalgae: Processes,
technologies and recent advancements,
Renewable and Sustainable Energy
Reviews, Volume 79, November 2017,
Pages
893-913,
DOI:
10.1016/j.rser.2017.05.199.
5. Sinha, S.; Agarwal, A.K.; Garg, S.
Biodiesel development from rice bran oil:
Transesterification process optimization
and
fuel
characterization.
Energy
Conversion and Management 2008, 49,
1248-1257.
6. Agarwal, A.K. Biofuels (alcohols and
biodiesel) applications as fuels for internal
combustion engines. Progress in Energy
and Combustion Science 2007, 33, 233271.
7. Quaye, E.C. Energy demands in the 21st
century: The Role of Biofuels in a
Developing Country. Renewable Energy
1996, 9, 1029-1032.
8. Barnwal B. K.; Sharma, M.P. Prospects of
Biodiesel production from vegetable oils in
India. Renew. Sust. Energy Rev. 2005, 9,
363-378.
9. Freedman, B.; Pryde E.H.; Mounts, T.L.
Variables affecting the yields of fatty esters
from transesterified vegetable oils. Journal
of the American Oil Chemists' Society
(JAOCS) 1984, 61, 1638-1643.
10. Zhang, Y.; Dube, M.A.; McLean D.D.;
Kates, M. Biodiesel production from waste
cooking oil: 1. Process design and
technological assessment. Bioresource
Technol. 2003, 89, 1-16.
11. Berchmans H.J.; Hirata, S. Biodiesel
production from crude Jatropha Curcas L.
seed oil with a high content of free fatty
acids. Bioresource Technology 2008, 99,
1716-1721.
12. Mohibullah, M. A. R. and MohdIqbal
Abdul Hakim: "Basic design aspects of
4.
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13.
14.
15.
16.
17.
micro-hydro-power plant and its potential
development in Malaysia", National Power
and
Energy
Conference
(PECon)
Proceedings, Kuala Lumpur, Malaysia,
2004.
http://
www.microhydropower.net/
Retrieved on 5 December 2017
http:// www.alternative-energy.info/microhydro-power-pros-and-cons/ Retrieved on
5 December 2017
CelsoPenche: "Layman's guidebook on
how to develop a small hydro site",
Published by the European Small
Hydropower Association (ESHA), Second
edition, Belgium, June, 1998.
Dilip
Singh:
"Micro-hydro-power",
Resource Assessment Handbook, An
Initiative of the Asian and Pacific Center
for Transfer of Technology, September,
2009.
https://en.wikipedia.org/wiki/Banswara,
Retrieved on 5 December 2017.
18. https://www.thewindpower.net/store_conti
nent_en.php?id_zone=1000, Retrieved on 6
December 2017.
19. http://www.renewableenergyfocus.com/vie
w/43408/welspun-renewablescommissions-126-mw-pratapgarh-windproject, Retrieved on 6 December 2017.
20. http://www.thehindu.com/2000/03/18/stori
es/0418221g.htm,
Retrieved
on
6
December 2017
21. http://pratapgarh.rajasthan.gov.in/content/r
aj/pratapgarh/en/business/infrastructure.ht
ml#, Retrieved on 6 December 2017
22. http://aquathermindia.com/biomass-basedpower-plants/, Retrieved on 6 December
2017
23. http://energy.rajasthan.gov.in/content/raj/en
ergy-department/rvunl/en/ourplant/hydel/mini-micro.html, Retrieved on
6 December 2017
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Design Analysis of Distribution Power Network in ETAP-A Case
Study
Urvi Shankar Marathe, Bhupendra R. Parekh
Department of Electrical Engineering, BVM Vidyanagar, Gujrat, India
Corresponding Author: urvi.s.marathe@gmail.com
ABSTRACT
Electrical Power system provides essential service to consumer. This research paper deals with the simulation
of One subdivision network of Baroda city is considered for simulation. Simulation is done in ETAP software
& Result is observed for different loading.
Keywords: ETAP, Distribution Network, Power flow Analysis in ETAP.
flow is given in this paper. Backward sweep
I.
INTRODUCTION
gives the value of Voltage & Current at
different busses by using number of iterations
With rapid Urbanization, Population is
& forward sweep gives composite system by
increasing at urban areas; Due to this to
which Imaginary part and Real part of the
transfer of reliable Power supply to consumer
voltages and currents can be decompose. [3]
end becomes critical. This happens due to high
This paper gives Monte Carlo simulation
congestion of distribution lines at service ends.
method; this paper gives algorithms to
so, that for the reliability of power design of
simulate unbalanced distribution system by
distribution system in proper way becomes
load flow. It considers random samples to
important. POWER flow studies are used to
compute results. By different system samples
evaluate network steady-state characteristics.
different simulation results come out. By
The solution method chosen in the base of
considering all results average results can be
accuracy
and
convergence
necessity.
considers. For Monte Carlo simulations
Distribution feeders supply unbalanced loads
voltage stability index is also required this can
and are not transposed. Furthermore, mutual
be study by [4] Basics of ETAP simulations are
impedances can be significant and aggravate
studied from [5]. Some advanced technologies
unbalance conditions. In addition to unbalance,
which are using in present distribution system
R/X ratios of distribution feeders are generally
are studied from [6] & [7]. [6] explains Ring
high as compared to those of transmission
main unit for different ratings and with new
lines. So, Distribution system requires
advanced features. It includes safe ring and
unbalanced load flow methods. A conventional
safe plus concept of ring main units. [7] gives
method for load flow analysis becomes
basic parameters, which are using in single
inaccurate. Power system load flow analysis is
phase and three phase transformers of
typical tool to check power system
distribution power network.
performance efficiently.
In this Papers unbalanced load flow is done on
II.
CASE STUDY
a subdivision of Baroda city distribution
system. This load flow is identified by
11/0.415 KV distribution feeder of a
considering similar network on distribution of
subdivision of Baroda area distribution
Nagpur, Maharastra[1].By considering some
network, Gujarat is considered for analysis.
assumptions and value of Impedances and
Two supply system hosts with power
Voltage ratings unbalanced load flow is done
transformers to feed supply to that area
and results are identified. Results differs from
feeders. One supply get from Gotri to
the given results are about 8%. unbalanced
Subhanpura feeder and other is from Jambuva
load flow methods are understood by [2], [3].
to Motibaug feeder. Load receives at voltage of
0.415KV. Below Fig 1 shows line diagram of
[2] explains load flow by forward-sweep &
substation under case study. This subdivision
backward-sweep method, algorithms for load
contains total 28 feeders in which 3 H.T
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feeders and 25 L.T feeders. Distribution of
feeders to both 11KV substations are assumed
as per the required load which has to feed to
each load.
This network is divided in to three parts. First
part contains primary & secondary feeders of
11/0.415KV Voltage ratings
1.
PRIMARY TRANSMISSION:-
Transmission System starts from Source
voltage 220KV and end to Motibaug and
subhanpura 11KV substations. This layout
includes primary and secondary Transmission
& Primary Distribution.
Fig 2 Secondary Distribution-1
Fig-1 Transmission and primary distribution System
2.
DISTRIBUTION SYSTEM:Some feeders supply loads from source-1 that
is Jambuva and other is from source-2 that is
Gotri. Fig 2 and Fig 3 show the Secondary
distribution system for Baroda subdivision
feeder loads .Here, Transformer ratings of
network is given in figure, Load is consider of
65% of Transformer KVA.
As any subdivision takes Power from
minimum two supplies. Some consumers will
be feed by Subhanpura Substation through
Motibaug 11KV feeder. This feeder will
supply Power to 3- H.T consumers and 11- L.T
consumers.
Fig 3 secondary Distribution-2
Some consumers will be feed by Gotri
Substation through Subhanpura 11KV feeder.
This feeder will supply Power to 11- L.T
consumers. No H.T consumer is connected to
this source.
III.
ONE LINE DIAGRAM OF
BARODA NETWORK:-
Fig 4, Fig5 & Fig 6 is basic layout for Power
Transmission & Distribution. Fig shows the
single line diagram network for Distribution
system for both the sources. Frequency is
considered as 50Hz & 65% load of all the supply
is consider.
Diagram is divided in three parts:
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1. Transmission System
2. Distribution System-1
3. Distribution System-2
This part contains Primary & Secondary
Transmission and Primary Distribution of
Network.
consumers. No H.T consumer is connected to
this source.
Fig 6 Secondary distribution system-2
IV.
RESULT OF LOAD FLOW AT
DIFFERENT LOADING CONDITIONS.
Fig 4 Transmission System of Network
As any subdivision takes Power from
minimum two supplies. Some consumers will
be feed by Subhanpura Substation through
Motibaug 11KV feeder. This feeder will
supply Power to 3- H.T consumers and 11L.T consumers.
Unbalanced load flow analysis has Done on
20%,50% &, 100,120% loading & PF%,
Current%, load% that has fulfilled at 66KV &
11KV Buses are compared. Load flow studies
are done by current injection method for
unbalanced load flow method. Initially,100%
load is taken. As only one subdivision is
consider some supply lines at 11KV substation
is not considered by open circuited circuit
breaker.
Fig-5 Secondary distribution system-1
Some consumers will be feed by Gotri
Substation through Subhanpura 11KV feeder.
This feeder will supply Power to 11- L.T
Fig-7 Load flow at distributor-1
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higher than 50% loading and nearer to 100%
load. This graph explains comparison of power
factors for Subhanpura, Gotri, Motibaug &
Subhanpura substations.
% Receiving Load
comparison:2.
Fig 8- Load flow at distributor-2
1.
Power factor comparison :-
Fig 10 Bus load at different %loading
Fig 9 Power Factor Comparison
From Fig 9, with increase in loading Power
factor improves, But it can be seen that at very
less loading i.e. 20% loading. Power factor is
From Fig 5, with increase in loading receiving
end buses Power improves, But it can be seen
that at very less loading i.e. 20% loading.
Receiving end load at bus is higher than 50%
loading and nearer to 100% load. This graph
explains comparison of Receiving end load for
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Subhanpura, Gotri, Motibaug & Subhanpura
substations
3.
Current comparison:-
.
V.
CONCLUSION
By using ETAP software load flow is done on
Baroda subdivision distribution network for
different loading conditions by using redial
system condition and effect on power
factor,receiving end Power & current is
compared. We can observe that at 20% loading
due to Ferranti effect effect on that loading its
effect is different than other 100%,50% &
120% load conditions.
REFERENCES
Fig 11 Current Comparison
From Fig 11, with increase in loading
receiving end buses Current reduces, But it
can be seen that at very less loading i.e. At
20% loading, Current is lower than 50%
loading and nearer to 100% load. This graph
explains comparison of Receiving end load for
Subhanpura, Gotri, Motibaug & Subhanpura
substations.
[1]
Kishor Porate,K.L Thakre,G.L
Bodhe,”Voltage stability Enhancement of Low
Voltage Redial Distribution Network Using
SVC
:A
case
study”WSEAS
TRANSACTIONS on POWER SYSTEMS.
[2] G.W. Chang, H.L Wang,”A Simplified
Forward & Backward sweep Approach for
Distribution system Load flow analysis”,2006
International Conference on Power System
Technology.
[3] Mini Thomas, Rakeshranjan ,Roma Raina”
Load Flow Solution for Unbalanced Radial
Power Distribution using Monte-Carlo
Simulation”, WSEAS TRANSACTIONS on
POWER SYSTEMS
[5] Kiran Natkar, Naveen Kumar” Design
Analysis of 220/132 KV Substation Using
ETAP” International Research Journal of
Engineering and Technology (IRJET), 02
Issue: 03 | June-2015.
[6] “SF6 insulated Compact Switchgear, type
Safe Plus and SF6 insulated Ring Main Unit,
type SafeRing 12 / 24 KV”ABB catalogue.
[7] guideline for specifications of energy
efficient Outdoor Type three phase and single
phase
Distribution
Transformers”,Govt.of.India Ministry of
power central authority new Delhi Aug 2008.
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Power system stability enhancement using fuzzy logic-based power
system stabilizer
Pargi Bhavinkumar Devjibhai, Akshay A. Pandya
Department of Electrical Engineering, BVM Vallabh Vidhyanagar
ABSTRACT
Power system is dynamic in nature and it is constantly subjected to disturbances. It is necessary
that these disturbances do not lead the system to unstable condition. Power system stabilizers(PSS)
are used to enhance the damping during low frequency oscillation under these disturbances. PSS are
designed using conventional and non-conventional controllers. Conventional controllers uses phase
lead compensation techniques, but they provide poor performance under different loading condition.
To cover wide range of conditions non-conventional controllers such as Fuzzy Logic controller can
be used. This paper presents the study about PSS using Fuzzy Logic approach to enhance stability of
single machine infinite bus system. Speed deviation and acceleration of synchronous machine are the
two inputs to the fuzzy logic controller. The supplementary voltage signals obtained from fuzzy logic
controller are given to excitation system of the synchronous machine. Results presented in this paper
shows that fuzzy logic-based PSS design gives superior performance than conventional PSS.
Keyword: SMIB, Power System Stabilizer(PSS), Fuzzy Logic Controller(FLC)
1.
INTRODUCTION
Power systems are subjected to low
frequency disturbance that might cause loss of
synchronism or an sometime it’s the reason for
whole system break down. The oscillations,
which are in frequency range of 0.2 to 0.3hz,
might be generate by the disturbance in system
or sometime build up spontaneously. These
low frequency oscillations are generator rotor
angle oscillations which limit the power
capability of the system and sometime they can
break the entire system. For this reason, power
system stabilizers are used to generate the
supplementary control signal to damp out these
low frequency oscillation(LFO). Now a days
mostly conventional power system stabilizer is
used to overcome these problems. The CPSS
can be designed using classical methods such
as eigen value, root locus, and phase
compensation etc. In this paper CPSS use
phase compensation where the gain setting is
already fixed for some situations or some
specific operations but the constant changing
nature of power system makes more difficult
task. So, it is more difficult to design a PSS that
could give good performance in all operations.
To overcome this problem fuzzy logic-based
tech. suggested. Using fuzzy logic-based tech.
mathematical model of system are not
necessary,
easy
to
improve
and
computationally efficient. The fuzzy logicbased PSS are designed on single machine
infinite bus system and compare the
performance between the CPSS and FPSS.
Result shows that the better performance of
fuzzy
logic-based
power
system
stabilizer(FLPSS) in comparison to the
conventional power system stabilizer(CPSS).
2. SYSCHRONOUS MACHINE MODEL
The performance of synchronous machine
connected to a large system through
transmission lines. Fig 1 show the
configuration of SMIB. Synchronous machine
connected to infinite line can be represented as
the thevenin’s equivalent circuit where Et is
terminal voltage and Eb is bus voltage.
Fig. 1: General configuration of system
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The above equation to describe small-signal
performance is represented in schematic Fig.
1.3
From the block diagram we have
Fig. 2: Equivalent system
Classical System Model:
The generator is represented as the voltage E'
behind Xd' as shown in Fig. 1.2. The
magnitude of E' is assumed to remain constant
at the pre-disturbance value. Let d be the angle
by which E' leads the infinite bus voltage EB.
The d changes with rotor oscillation. The line
current is expressed as
Fig. 3: classical model of generator
Fig. 4: Block diagram of SMIB with classical
model
With stator resistance neglected, the air-gap
power (Pe) is equal to the terminal power (P).
In per unit, the air-gap torque is equal to the air
gap power.
Solving block diagram we get char. Equation:
Compare with general form, the undamped
natural frequency and damping ratio as
3.
POWER SYSTEM STABILIZER
The basic function of power system stabilizer
is to add supplementary signal to the generator
rotor oscillations by controlling its excitation
using auxiliary stabilizing signals. Foe provide
damping signal the must produce a component
of electrical torque in phase with rotor speed
deviations. The fig. shows the block diagram
of PSS. The CPSS can use input as speed
deviation of generator shaft, accelerating
power or even the terminal bus frequency. In
this paper the speed deviation is used as input
and voltage signal as output of CPSS.
Fig. 5: block diagram of SMIB with PSS
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4.
FUZZY CONTROLLER
Fuzzy logic control system are rule based
system which a set of fuzzy rules present a
control decision to adjust the effect of certain
system simulation With the help of effective
rule base we can improve our system more and
control also increase. The fuzzy logic
controller provide an algorithm which can
convert the control strategy into automatic
control strategy. Fig. shows the fuzzy logic
controller which consists of a fuzzification
interface, a knowledge base, control system,
decision making logic. And a defuzzification
interface.
5.
SIMULATION AND RESULTS
The performance of SMIB has been studied
(1)
With excitation system
(2)
With conventional PSS
(3)
With fuzzy logic-based power system
stabilizer
The data taken from:
Fig. 6: design of fuzzy logic controller
Fig. 7: SMIB with AVR only
(1)
With excitation system
The model used in the Simulink is shown in the
fig. In this paper the term K is constant. And
the value of K calculated by using above
parameters:
K1 0.7635, K 2 0.8643, K3 0.3230, K4 1.4188
Fig. 8: system response with K5 negative
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(2)
With conventional power system
stabilizer(CPSS)
(3)
With fuzzy logic based power
system stabilizer
Fig. 9: SMIB with AVR and PSS
Fig. 11: Simulink model with fuzzy logic
based PSS
Fig. 10: variation of angular speed, angular
position and torque when PSS is applied with
K5 negative and positive
Fig. 12: results of variations of angular speed
and angular position when system with fuzzy
logic-based PSS
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6. Conclusions
In this paper work is carried out to dampout the
oscillation of the power system using fuzzy
logic based controller on a single machine
infinite bus system. FLPSS shows that superior
performance than the power system stabilizer
in term of settling time and damping effect. So,
we can conclude that the performance of
FLPSS is more better than conventional power
system stabilizer.
1.
2.
3.
4.
5.
6.
7.
REFERENCE
K.Gowrishankar, M.D.Masud khan 2012.
Matlab Simulink Model Of Fuzzy logic
controller with PSS and its performance
anlaysis
Kamalesh
Chandra
Rout
And
Dr.P.C.Panda 2010. Dynamic Stability
Enhancement of Power System Using
Fuzzy Logic Based Power System
Stabilizer
D. K. Sambariya, R. Gupta and A.K.
Sharma 2005. Fuzzy Application To
Single Machine Power System Stabilizer
Neeraj Gupta And Sanjay K. Jain 2010.
Comparative Analysis of Fuzzy Power
System Stabilizer Using Different
Membership Functions
Jenica
Ileana
Corcua
And
EleonorStoenescun 2007. Fuzzy Logic
Controller as a Powers System Stabilizer
Manish kushwaha and Mrs. Ranjeeta
khare
2013.
Dynamic
Stability
Enhancement of Power System using
Fuzzy Logic Based Power System
Stabilizer
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Impact of Facts Device on Protective Distance Relay
Taral Falgunibahen R., Rashesh P. Mehta
Electrical Engineering Department, BVM Vidtanagar Gujrat, India
Corresponding Author: falgunitaral@gmail.com
Abstract
This paper presents simulation of protective distance relay with and without FACTS (Flexible AC
Transmission System) device such as STATCOM (Static synchronous compensator). FACTS Device
are widely used to improve long transmission line capacity and increases reliability of system. But
when STATCOM is connected in transmission line and fault is after STATCOM, it has a great impact
on distance relay tripping characteristics. Simulation result is used to discuss the impact of distance
relay for different mode of STATCOM located on Transmission line. We verify the proposed model
under different types of fault and fault locations. The simulation is carried out in PSCAD software.
Keywords – FACTS devices, Distance relay, MHO relay, Modelling PSCAD/EMTDC
1.
Introduction
In recent years due to industrialization and
urbanization life styles, there is tremendous
increase in electric power demand. This makes
existing system very complex. So to meet this
electrical power demand new transmission
lines can be added or some devices can be
installed on existing transmission line without
affecting efficiency and reliability of the
system. Installing new transmission line in
power system can increase technological
complexities, economic and environmental
problems. So, adding new devices such as
FACTS (Flexible AC Transmission System)
have supported the transmission system and
increase the capacity of transmission line.
With the help of FACTS devices bus voltage,
line impedance and phase angle in the power
system can easily be manipulated and rapidly
regulated to increase the stability of the
system. But installing FACTS devices in
transmission not only change the impendence
but also change the voltage and current signals
due to addition of decaying DC component,
sub synchronous frequency components and
odd-harmonics component. [1] Distance
protection is mainly used to protect the
transmission line. Its principle depends on
electrical measures like voltage and currents.
Distance relay measure the impedance
between relay location and fault point by
measuring the voltage and current ratio
computation. This impedance is directly
proportional to the length of transmission line.
The relay will operate when ratio of voltage
and current i.e. impedance is less than the line
impendence. But the presence of FACTS
devices in fault loop affects both transient and
steady state components of voltage and current
at the relay point. This causes distance relay in
overreach or under reach problem, which
results in unwanted tripping signal given to the
circuit breaker in the presence of FACTS
devices in transmission line. [2, 3]
Therefore, it is very important to study the
impact of FACTS devices on traditional
protective relay scheme such as distance relay
for transmission line.
This paper will analyse impact of STATCOM
on distance relay when STATCOM is
connected in transmission line. A model of
distance relay with STATCOM proposed in
PSCAD. The simulation results obtained after
installing FACTS devices in transmission line
clearly show the impact of FACTS devices on
distance relay.
2.
FACTS Devices
The IEEE defines FACTS as “Alternating
current transmission systems incorporating
power electronics-based and other static
controller to enhance controllability and
increase power transfer capability”. FACTS
Controller can be divided into four categories:
Series controller: In principle, all series
controller inject voltage in series with the
line. Variable impedance multiplied by
current flow through it, represents an
injected series voltage in the line. This
series controller could be variable
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impedance, such as capacitor and inductor.
This only supply or consumes variable
reactive power.
Shunt controller: They represent current
source connected in shunt with the line.
Shunt Controllers only generate or absorb
reactive power due to the injected current in
phase quadrature with line voltage.
Combined series-series controller: This
could be a combination of separate series
controllers, which are controlled in a
coordinated manner in a multiline
transmission line. They control active as
well as reactive power.
Combined series-shunt controller: This
could be a combination of separate shunt
and series controller, which are controlled
in a coordinated or Unified Power Flow
Controller with series and shunt elements.it
also control active and reactive power. [4]
STATCOM is one of the key FACTS
controllers. It can be based on a voltage source
converter or current-source converter. The
voltage soured converter is most preferable.
The STATCOM converts the input voltage
(Vdc) into three phase output voltages with
desired amplitude, frequency and phase or the
output voltage of the inverter must be in
synchronous operation with the system voltage
under any condition. STATCOM also
designed to act as an active filter to reduce
harmonics in the system. STATCOM installed
in transmission line for many applications such
as:
Increasing the
power
transmission
capability
Improving the transient and steady state
stability
Damping of power oscillation also
improving
Power factor correcting
Current harmonics eliminating
HVDC-link performance improving
Based upon the system application
STATCOM is connected in the system. The
voltage sag is largest at the midpoint of
transmission line, so best location of
STATCOM is midpoint of transmission line.
For a radially fed loads, the best location for
STATCOM is at load end. STATCOM absorbs
or generate the reactive power and maintain
them within an acceptable level. In this paper
12-pulse IGBT type STATCOM is used. [4, 5]
3.
Distance Relay
Distance relay are used for protection of long
and extra high voltage transmission line,
transmitting power at 132 KV, 220 KV, and
400 KV. The settings of distance relay can
easily be carried out and they provide back-up
protection as compared to other relay like over
current relay. The over current relay
principally dependant on only magnitude of
fault current. There are some parameters in
transmission line such as source impedance,
line resistance, fault location, type of fault etc.
These parameters affect the measurement of
current by the relay, which causes
unsatisfactory performance of overcurrent
relay. [8]
Distance relay able to detect a fault in
transmission line which depends upon the
impedance of transmission line which is
function of length transmission line. There will
be a change in determined impedance because
the fact that current will increase and voltage
decrease when fault occurs. Therefore
impedance will decrease according to ohm’s
law and distance relay compare this value with
pre-set value, if measured value is smaller than
pre-set value then fault is detected and tripping
signal is issued to circuit breaker to isolate the
healthy portion from faulty portion. Distance
relay does not provide protection of 100% line
because the error in current and voltage
transformer. [5] The highest error in
impedance measurement is occurs under a
faulty condition that is located anywhere from
85% to 100% of protected line. To solve this
error in impedance measurement, the zone-1 is
set about 85% of the section to be protected.
The distance relay operates instantaneously if
the fault occurs in zone-1. The zone-2 covers
the first line section plus approximately 50%
of the next line section. And operate with
sufficient time delay while zone-3 of this relay
encompasses the full second line section and
provide the back-up protection for
transmission line. [8]
In this case the mho relay is taken and zone
wise fault is creates and compare result.
4.
Simulation Scheme
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To explain and simulate the power system
using two sources including STATCOM and
DISTANCE RELAY at the sending end, the
PSCAD/EMTC software used. PSCAD is
graphical user interface, provide vary flexible
interface to the electromagnetic transient
simulation software. [12]
Connect FACTS device such as STATCOM
with transmission line and effect of
STATCOM on protective distance relay is
observed by MHO characteristics of distance
relay.
Table 1 simulation data
System Voltage
500 kv, 3 Phase
Supply Frequency
60 Hz
X’mission
length(TL1+TL2+TL3)
line
300 km
Positive Seq. Impendence
0.0127+j0.3520
Ω/km
Zero Seq. Impendence
0.3864+j1.5556
Ω/km
STATCOM Rating
± 100 Mvar
Simulation:
Table 2 Settings of Zones of Protection
Zone
R
X
Zone
1
Zone
2
Zone
3
5.
1.082Ω
29.902Ω
1.5276Ω
42.218Ω
2.8006Ω
77.39Ω
Simulation Results
Fig.1 shows a typical 300km, 500KV
transmission line. The Power system
simulation includes three main parts…
(1) Compile all the parts of distance relay: The
inputs of distance relay are voltage and current
at relay location and the output are resistance
and reactance of transmission line. Fault types
are stored in PSCAD to use it later to draw the
impedance trajectory and tripping signal.
(2) Second 12 pulses STATCOM is design in
PSCAD environment and it has many
applications like regulating voltage by setting
the desired reference voltage, fix reactive
current and fix the reactive power.
(3) Other power system components required
are transmission line, three phase source,
loads, and circuit breaker.
dist_relay1 : XY Plot
X Coordinate
Ra
Rb
Rc
Y Coordinate
Xa
Xb
Xc
+y
100
50
0
-x
+x
-50
-100
-100
-50
-y
0
Aperture
Figure 1 500kv, 300km transmission line with
STATCOM simulation
50
100
Width 0.5
0.000s
0.500s
Position 0.000
Figure 2 Fault at 50km without STATCOM
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dist_relay1 : XY Plot
dist_relay1 : XY Plot
X Coordinate
Ra
Rb
Rc
X Coordinate
Ra
Rb
Rc
Y Coordinate
Xa
Xb
Xc
150
150
100
100
50
50
0
-x
0
+y
200
+y
200
Y Coordinate
Xa
Xb
Xc
+x
-x
+x
-50
-100
-50
-150
-100
-200
-150
-200
-200
-200
-y
0
-100
100
100
200
Width 0.5
0.000s
200
0.500s
Position 0.000
Figure 5 with STATCOM (inductive mode)
Width 0.5
0.500s
-y
0
Aperture
Aperture
0.000s
-100
Position 0.000
dist_relay1 : XY Plot
Figure 3 with STATCOM at 100km fault at 5okm
In this case line to ground (AG) fault taken at
50km and STATCOM is at 100km. The
measured impedance is all most same with and
without STATCOM. But if fault at 205km and
STATCOM is in capacitive mode and its
location is at 100km, fault occurs in zone 3 but
impedance trajectory show the fault is out of
zone.
X Coordinate
Ra
Rb
Rc
Y Coordinate
Xa
Xb
Xc
150
+y
100
50
-x
0
+x
-50
dist_relay1 : XY Plot
-100
X Coordinate
Ra
Rb
Rc
Y Coordinate
Xa
Xb
Xc
150
-150
-150
-100
-50
-y
0
Aperture
100
150
Width 0.5
0.000s
+y
50
0.500s
Position 0.000
Figure 6 Fault at 205km without STATCOM
100
50
-x
0
+x
-50
-100
-150
-150
-100
-50
-y
0
Aperture
50
100
150
Width 0.5
0.000s
0.500s
Position 0.000
Figure 4 Fault at 205km without STATCOM
From the above simulation result the following
conclusions can be drawn:
The STATCOM is located within the
fault loop affects the distance relay
performance.
During a fault, the apparent impedance
will decrease if the STATCOM consumes
reactive power from the system and the
apparent impedance will increase if the
STATCOM supply the reactive power.
Distance relay will over reach when the
STATCOM consumes the reactive power and
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it will under reach when supply the reactive
power.
Position of distance relay will also
affects the distance relay performance.
Figure 7 with STATCOM (capacitive mode)
6.
Conclusion
This paper presents the 500kv, 300km long
transmission line simulation with STATCOM
and having three zones. STATCOM is
installed for reactive power compensation.
Fault is created in different zones and zone
wise results taken with and without
STATCOM connected. STATCOM in its
capacitive mode results in under reach and its
inductive mode results in over reach problem.
There will be adverse effect on distance relay
when STATCOM is in fault loop.
7.
References
1.
N.G.Hingorani and L.Gyugyi 2000.
Understanding
FACTS
concept
and
technology of flexible AC transmission system
IEEE press.
2.
Gerhard Ziegler, 2006 Numerical
distance protection principle and Application,
2nd Ed, berlin and menschen Siemens
Aktiengesellschaft, Ed. Erlangen, Germany:
publics corprate publishing.
3.
M.P.Thakre, V.S.Kale, Jan 2014
.Distance protection for long transmission line
using PSCAD, International Journal of
Advance in Engineering & Technology
(IJAET), Vol.6, Issue 6, pp.2579-2586.
4.
M.P.Thakre, Dr. V.S.Kale, 2014.
“Impact of STATCOM on distance relay",
International Conference on Circuit, Power
and Computing Technology (ICCPCT-2014).
5.
Ahmed Albehadili, Ikhlas AbdulQudar 2015, Analysis of Distance relay
performance on Shunt FACTS – Compensated
Transmission Line (IEEE-2015).
6.
Dannana Hemasundar, M.P.Thakre,
Dr. V.S.Kale 2014. Impact of STATCOM on
Distance relay- Modeling and simulation
Using PSCAD/EMTDC, Conference on
Electrical, Electronics and Computer Science
(IEEE-2014).
7.
Mojtaba khederzadeh, 2002. Impact of
FACTS devices on Digital multifunctional
protective relay, (IEEE-2002).
8.
Power
system
protection
and
switchgear
by
Bhuvanesh
A
Oza,
Nirmalkumar C Nair, Rashesh P Mehta, and
Vijay H Makwana.
9.
Krishna T. Madreware, Vivek. R.
Aranke, Gorakshnath B. Abande,2015.Effect
analysis of shunt device on distance protection
in PSCAD and MATLAB for L-G Fault,
International Conference on Energy and
Application (ICESA 2015).
10.
Hadi H. Alyami, 2015.protective relay
model for electromagnetic transient simulation
International Journal of Innovative Research in
Advanced Engineering (IJIRAE) volume 2
Issue 1(January 2015)
11.
Cesar Rincon, Entergy, Jackson MS,
39215 Joe Perez, P.E., ERLPhase Power
Technologies, Bryan, TX77802 Calculating
load ability limit of distance relay.
12.
EMTDC/PSCAD
Simulation
Software, Ver.4.5
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Study and Review of Design and Simulation of CCM Boost Converter
for Power Factor Correction Using Variable Duty Cycle Control
Bharat S. Suthar, Swapnil Arya
Department of Electrical Engineering, BVM Vallabh Vidyanagar,Anand, Gujarat,India
Corresponding Author: sutharbharat06@gmail.com
ABSTRACT
In an electrical Power system, a load with a poor power factor draws more current than high power
factor for the same amount of useful power transferred. With the vast development in the usage of
Power electronic devices like Rectifiers (non-linear loads) the current drawn from the line is distorted
resulting in a High Total Harmonic Distortion (THD) and Low Power Factor (PF). Hence there is a
continuous need for Power factor correction and reduction of line current harmonics. The most
popular topology for Active PFC is a boost converter as it draws continuous input current. The aim
of this work is to develop an active PFC control circuit using CCM boost converter implementing
variable duty cycle control. It also regulates the output DC voltage.
Keywords: Power Factor Correction, CCM Boost converter, Total Harmonic Distortion Variable
duty cycle
Ι. INTRODUCTION
Extensive use of power electronic
devices has given rise to the need of making
power management flexible, smart and
efficient. Nonlinear current drawn by power
electronic devices affects the power quality.
Most of the electrical and electronic appliances
such
as
laptops,
desktops,
UPS
(Uninterruptible power supply), and VFD
work on D.C supply. Designing D.C power
supplies for such applications is very
necessary.
AC to DC converter or rectifier is a
device that converts ac to dc and this
conversion is done by switching devices such
as diodes, thyristors, power MOSFET’s, etc.
AC to DC converter consisting of diode with a
large output filter capacitor is cheap and robust
but very inefficient. Due to the non-linear
behaviour of the switches they tend to draw
highly distorted input current relative to the
line voltage. As a result, input power factor
becomes very low and also produces a
harmonic that may interfere with other
equipment. Low power factor results in poor
output voltage regulation, therefore increased
current and losses. Moreover, utilities will
charge a higher cost to industrial and
commercial clients having a low power factor.
Thus, overall efficiency of the system is
degraded.
Fig 1 : Input current waveform of the nonlinear
load with and without power factor correction
circuit.
To improve the power quality of the
distribution system two types of power factor
correction topologies are used, (1) Passive
power factor correction topology and (2)
Active power factor correction topology.
Passive PFC techniques incorporating L and C
components are the best choice for linear loads
because Passive power factor correction
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technique has a poor dynamic response and
lack of voltage regulation. For nonlinear loads
active PFC techniques are preferred due to
their superior performance more than passive
PFC techniques. Active PFC can be
implemented by using any one of the following
topology: Buck, Boost and Buck-Boost
Topology. Buck and Buck-boost converters
produces pulsed input current requiring
additional filtering. The fundamental property
of the boost converter is to produce a smooth
input current waveform, therefore reduce
filtering action is require and also increases
efficiency of the system. By reducing the
inductor-current ripple, the boost converter
decreases current stress and increases the
current handling capability at heavy loads for
these reasons, the boost PFC circuit operating
in continuous conduction mode (CCM) is the
popular choice for medium- and high-power
applications.
The general goal of the boost PFC
converter is to turn the switch (S ) off and on
rapidly and with a varying duty cycle in order
to make the input current (i ) sinusoidal and in
phase with the input voltage (v ).
Π
IMPLEMENTATION
OF
ACTIVE
PFC
CONTROLLER
USING BOOST CONVERTER IN
CCM MODE
Fig 2 : Boost PFC topology
Block diagram of the boost converter
PFC is as shown in above Figure 2. It consists
of boost inductor, switch (MOSFET, IGBT
etc.), fast recovery diode, capacitor and control
circuit. It has a smooth input current because
an inductor is connected in series with the
power source as shown in fig 2. The boost
converter controls two functions : first- shape
of the source current and second- magnitude
of the output voltage. To accomplish this, there
are two necessary conditions: first - the output
voltage should be higher than the peak of the
rectified input voltage, and second- the power
flow should be unidirectional. Current path for
different time instants can be considered as
shown in the Figure 3 and Figure 4.
Fig 3 : Current path for the ON state of the
switch
Fig 4 : Current path for the OFF state of the
switch.
The boost PFC circuit consists two
states. The first state occurs when S is closed,
as shown in Figure 3. When in this state, the
inductor is being energized by the AC side of
the circuit via the rectifier, and thus the
inductor current will be increasing. At the
same time, diode D becomes reverse biased
(because its anode is connected to ground
through S ), and energy is provided to the load
by the capacitor. Figure 4 shows the second
state, which occurs when S is open. In this
state, the inductor de-energizes (the current
decreases) as it supplies energy to the load and
for recharging the capacitor.
The boost PFC converter implements
two control loops-a voltage loop and a current
loop. The objective of voltage loop is to
regulate the output voltage of boost converter
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and the objective of current loop is to make the
supply current to follow the sinusoidal
waveform of the supply voltage, providing
high power factor (PF) and low total harmonic
distortion (THD). Current control loop
implements average, peak or hysteresis current
control.
Ш BOOST PFC CONVERTER
WITH VARIABLE DUTY CYCLE
CONTROL
For simplicity, the following assumptions
are made:
1) All the devices and components are
ideal;
2) The ripple of the output voltage is
too small to be neglected; and
3) The switching frequency is much
higher than the line frequency.
Source voltage VS ,
VS VP sin t …………………….(1)
Where, VP is the peak value of the source
voltage and is the angular frequency of the
source voltage.
The rectified voltage,
Vd V p | sin t | ……………………..(2)
V p Dy2
1
iLavg (t ) iLpk (t )( Dy Dr )
2
2 Lf s
sin t
Vp
1 | sin t |
Vo
……………………………..(6)
Thus the supply current is,
V p Dy2
sin t
is (t )
V
2 Lf s
1 p | sin t |
Vo
……………………………….(7)
Fig. 5 shows that the envelope of the peak
value of inductor current is sinusoidal.
However, the envelope of the average value of
inductor current is not sinusoidal and contains
distortion it. For analysis purpose the average
inductor current is normalized with the base of
(Vm Dy2 2 Lf s )(1 Vm V0 ) , so (7) is rewritten as,
sin t
V
1 P | sin t |
Vo
…………………………………(8)
is (1
Vp
Vo
)
The inductor peak current is,
V | sin t |
V
iLpk (t ) d DyTs p
DyTs
L
L
……………………….(3)
where, Dy is the duty cycle corresponding
to the ON time of the switch; Ts is switching
period.
In a switching cycle, the inductor has a voltsecond balance,
Vd DyTs (VO Vd ) Dr Ts
…………………………………..(4)
Dr is the duty cycle corresponding to the
OFF time of the switch; VO is the output
voltage of the boost converter
Equation (4) can be written as,
V p | sin t |
Vd
Dr
Dy
Dy
VO Vd
Vo V p | sin t |
……………………………..(5)
From (3) and (5) average inductor current is,
Fig 5 : Inductor waveform in a half line cycle
Assume 100% efficiency for the converter,
i.e. Pin Po the duty cycle is,
Dy
1
Vm
2 Lf s Po
sin 2 t
d t
0 Vp
1 | sin wt |
Vo
………………………………….(9)
IV. VARIABLE DUTY CYCLE
CONTROL TO IMPROVE THE
INPUT POWER FACTOR
In (9) is assumed to be constant. In order to
achieve power factor nearer to unity is
assumed to be variable as follows,
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Vp
| sin t |
Vo
………………………………..(10)
Substitution of equ. (10) in to equ.(7) leads to
V p D02 | sin t |
is (t )
2 Lf s
……………………………..(11)
Assuming 100% efficiency for the converter
the average input power is derived as,
1 V D2 V 2 D2
Pin Vm m 0 m 0 po
2
2 Lf s
4 Lf s
…………………………………(12)
P Lf
Do 2 o s
Vm
……………………………………….(13)
Substitution of equ. (13) in to equ. (10)
2 Lf P
2 Lf P
Vp
Vp
s o
s o
Dy
1 | sin t |
1
Vp
Vo
Vp
Vo
……………………………………(14)
The Duty cycle expressed in (14) is
complicated It can be simplified as follows
Assuming a Vm Vo ; y | sin t | , (10) can be
rewritten as,
Dy Do 1 ay
Dy Do 1
VI. CONCLUSION
This paper presents variable duty cycle
control for CCM Boost PFC converter. CCM
mode of boost converter is chosen which
features smaller inductor current ripple
resulting in low RMS currents on inductor and
switch thus leading to low electromagnetic
interference. Using this technique input current
is made to follow supply voltage effectively.
Thus the input power factor for diode bridge
rectifier is improved and harmonic content in
the input current is reduced. It also regulates
the output DC-bus voltage
……………………………(15)
Based on Taylor’s series,
1
1
f ( x) f ( x0 ) f ' ( xo ) f " ( x0 )( x x0 ) 2 ... f ( n ) ( x0 )( x xo ) n ...
2!
n!
Fig 6 : CCM Boost converter
…………………(16)
Equation (15) can be expressed as
REFERENCES
1
3
a
1 a2
Dy Do [ 1 ay (1 ay0 )] 2 ( y yo )
(1 ayo(1)
) 2 (Sujata
y yo )2Powniker,Student
...]
Member, IEEE
2
2! 4
and Sachin Shelar, Member, IEEE
………………….(17)
“Development of Active Power Factor
Reserving only first derivative term, (17) is
Correction Controller Using Boost
approximated as
Converter” IEEE International WIE
1
a
a
Conference
on Electrical and Computer
Dy _ fit Do [ 1 ay (1 ay0 )] 2 ( y yo )] D1 (1
y)
Engineering
December 2016, AISSMS,
2
2 ayo
Pune, India
…………………………..(18)
(2) M. Nirmala “Design and Simulation of
Where D1 ( D0 (2 ay0 )) (2 1 ay0 )
CCM Boost Converter for Power Factor
Correction Using Variable Duty Cycle
V. SIMULATION
Control” International Journal of
Fig. 6 shows the MATLAB simulations of
Electrical,
Computer,
Energetic,
CCM boost PFC converter with variable duty
Electronic
and
Communication
cycle control.
Engineering Vol:8, No:1, 2014
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(3) P. Suresh kumar, S. Sridhar, T. Ravi
kumar “ Design and Simulation of Boost
Converter for Power Factor Correction
and THD Reduction” 2014 IJSETR
Vol.03,Issue.42
(4) Saubhik Maulik, Prof. Pradip Kumar
Saha, Prof. Goutam Kumar Panda “ Power
Factor Correction By Interleaved Boost
Converter Using PI Controller” Int.
Journal of Engineering Research and
Applications www.ijera.com ISSN : 22489622, Vol. 3, Issue 5, Sep-Oct 2013
(5) Hiten Pahilwani “Power factor correction
using boost converter” International
Journal of Application or Innovation in
Engineering & Management Volume 4,
Issue 8, August 2015
(6) P.V.R.K.B.A.N.Raju ,I.Sudhakar babu,
Dr. G.V.Siva Krishna Rao “ Simulation of
Active Power Factor Correction Using
Boost Type Converter” International
Journal of Science, Engineering and
Technology Research (IJSETR), Volume
3, Issue 10, October 2014
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Dynamic Voltage Restorer for Power Quality Improvement
Jain Shilpa Pavan, Bhupendra R. Parekh
Department of Electrical Engineering, BVM Vallabh Vidyanagar, Anand, Gujarat, India
Corresponding Author: jainshilpa137@gmail.com
Abstract
Power quality is one of the chief concerns in distribution system in commercial and modern industrial
application. The problem of power quality is manifested as nonstandard voltage, current or frequency
which may result to the failure of end user equipment. Transients sags, swells and harmonic distortion
contribute to the critical problems in power quality out of which the sags and swells are predominantly
found and have severe effect on sophisticated device whose performance is very sensitive the power
supply quality. Custom Power Device is used to overcome this problem. DVR is one of the most
efficient and modern custom power device used in power distribution system. It includes the
advantage of lowest cost, smaller size and fast dynamic response to the disturbance. This paper
presents the modelling, analysis and simulation of DVR using MATLAB/SIMULINK based on PI
controller. The simulation results show the effectiveness of DVR for voltage sag mitigation and a
better voltage profile.
Keywords: Dynamic Voltage Restorer, Power Quality, voltage sag, voltage source inverter
I.
Introduction
Power quality is the delivery of sufficiently
high grade electrical services to the
customer.The modern industrial devices used
nowadays are typically based on the electronic
devices such as programmable logic
controllers, variable speed drives and other
precision electronic equipments, which are
extremely susceptible to disturbances such as
voltage sags, swells and harmonics .Amongst
all the problem of voltage sag is considered to
be one of the most severe problems to the
industrial equipments.. Sag, as defined by
IEEE
standard
1159-1995,
IEEE
Recommended Practice for Monitoring
Electric Power Quality, is a “decrease in RMS
voltage or current between 0.1 p.u and 0.9 p.u,
at the power frequency for durations from 0.5
cycles to 1 minute”. The problem of power
quality may arise due to a variety of events
ranging from switching actions at the customer
ends or faults on transmission lines. Voltage
sag can cause an unacceptable function and
eventual shut down of industrial machines and
equipments, resulting loss of production and
operation. Voltage compensation can be
achieved by installing A custom power device
is used to suppress out the disturbances at the
customer
end
to
achieve
voltage
compensation. The DVR is considered as a
competent custom power device for mitigating
the impact of voltage disturbances on sensitive
load. It also has added features like low cost,
fast dynamic response, and compensation of
harmonic and reactive power.
II.
Dynamic Voltage Restorer
A DVR is the most efficient and effective
modern custom power device used in power
distribution networks. The DVR as shown in
figure 1 is a series connected solid state device
that injects additional voltage required by load
into the supply system in order to adjust the
load voltage to the desired amplitude and
waveform even when the source voltage is
unbalanced or distorted. This process involves
insertion of real/reactive power from DVR to
distribution feeder for voltage compensation.
A DVR prevents voltage sag and provide
voltage regulation. It can also work as a
harmonic isolator to prevent the harmonics in
the source voltage reaching the load. The heart
of the DVR is Control unit, whose main
function is to detect the presence of voltage
sags in the system and calculate the required
compensating voltage for the DVR so that
appropriate reference voltage is generated for
PWM generator and accordingly gate pulses
triggered on the PWM inverter.
III.
Operating modes of DVR
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A.
Protection mode: If the over current on
the load side exceeds a permissible limit due to
Fig. 1 Block diagram of DVR
short circuit on the load or large inrush
current, the DVR will be isolated from the
systems by using the bypass switches (S2 and
S3 will open) and supplying another path for
current (S1 will be closed).
B.
Fig. 2 Mode of operation
C.
Standby mode: Under the normal
conditions the DVR may either go into short
circuit or inject very little voltage for
compensation of voltage drops on transformer
reactance and losses.
D.
Injection/boost mode: As soon as the
sag is detected DVR goes into boost operating
mode. For compensation, AC voltage is
injected in series to the feeder with required
magnitude and phase.
IV.
Power circuit
A.
Injection/Booster transformer: The
basic purpose of injection transformer is to
connect the DVR to the distribution feeder
through the HV-windings and adds DVR
voltage which is generated by Voltage Source
Inverter (VSI) to the incoming supply voltage
after the detection of any sag by the control
unit. This transformer increases the DVR
voltage to the desired level.
B.
DC-link and Energy Storage Devices:
The DC-link and energy storage device
provides the real power requirement of DVR
during compensation period. Flywheels,
batteries, superconducting magnetic energy
storage (SMES) and super capacitors can be
used as an energy storage device.
C.
Voltage Source Inverter (VSI): VSI is
a power electronics system consists of à dc
link/energy storage device, and it can produce
a sinusoidal voltage. The function of the VSI is
to convert the dc voltage supplied by the
energy storage device/dc-link into an ac
voltage.
D.
Harmonic filter: The main task of the
filter is to keep the harmonics voltage content
generated by the VSI to the permissible level.
By locating the filter at the inverter side the
higher order harmonics are prevented from
penetrating into transformer, thereby it
decrease the voltage stress on the injection
transformer. But there can be a phase shift and
voltage drop in the inverter output, which can
upset the control algorithm. By locating the
filter at the load side phase shift cannot be
occur but harmonics can penetrate into the high
voltage side of the transformer, a higher rating
transformer is required.
E.
By-pass Switch: The DVR is a series
connected device and one of the drawbacks
with series connected device is the difficulties
to protect the device during short circuits and
avoid interference with the existing protection
equipment. During faults, overload or at time
of maintenance a bypass path for the load
current has to be ensured.
V.
Control circuit
The aim of the control circuit is to keep
constant voltage magnitude at the point where
a sensitive load is connected, under voltage
disturbance. The control system measures the
rms voltage at the load point. No reactive
power measurement is required. The VSI
switching strategy is based on SPWM
technique which offers simplicity and good
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response. The PI controller method identifies
the error signal and generates the required
angle δ to drive the error to zero, i.e., the load
rms voltage is brought back to the reference
voltage V ref. In the PWM technique, the
sinusoidal signal Vcontrol is compared against
a triangular signal (carrier) in order to generate
the switching pulses for the VSI switches. The
block diagram of control is shown in figure 3.
Figure 4 shows the test system used to carry
out the DVR simulations is presented in this
section. The DVR coupling transformer is
connected in delta in the VSI side. The DVR
system is composed by a 13 kV, 50 Hz supply
system, feeding two transmission lines through
a 3-winding transformer connected in Yg/Δ/Δ:
13KV/115KV/115 kV. Such transmission
lines feed two distribution systems through
two transformer of 115KV/11 KV. This test
system is analyzed under three phase short
Fig. 3 Block diagram of control system
VI.
Simulation and results
The following table shows the specifications
used for the simulation of DVR model.
DVR parameters
Values
Main supply
13 KV
voltage
Series Transformer
1:1
Turn ratio
DC bus voltage
5KV
Active Power 1000W
Load
Reactive power 500W
Line resistance
0.001Ω
Line inductance
0.005 H
Source resistance
0.1Ω
Fault resistance
0.66Ω
Switching
1080 Hz
frequency
Line frequency
50 Hz
Table. 1 System parameters and control
values
The performance of DVR with these designed
parameters is evaluated by performing it’s
simulation in MATLAB/SIMULINK.
circuit fault.
Fig. 4 MATLAB/Simulink Model of DVR
The first simulation contains no DVR and a
three-phase short-circuit fault is applied at
point before injection transformer, via a fault
resistance of 0.66 Ω, during the period 0.4 to
0.6 sec. The R.M.S voltage at the load point is
0.32 p.u as shown in Figure 5.
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be very robust in that case. The DVR has been
modeled
and
simulated
in
MATLAB/SIMULINK. The simulations
carried out here showed that the DVR provides
relatively better voltage regulation capabilities
and successful mitigation of voltage sag
REFERENCES
1.
Figure. 5 Load voltage without DVR
The second simulation is carried out using the
same scenario as above, but now DVR is
connected to the system, then the voltage sag
is mitigated almost completely, and the rms
voltage at the sensitive load point is maintained
at 0.8 p.u.as shown in Figure 6.
2.
3.
4.
5.
Figure. 6 Load voltage with DVR
VII. Conclusion
The performance of DVR has been analyzed
for linear load. The Voltage Source Inverter
(VSI) was implemented with the help of
Sinusoidal Pulse Width Modulation (SPWM).
The control scheme was tested under three
phase fault conditions, and it was observed to
6.
Rakeshwri Pal, Dr. Sushma Gupta,2
December 2016. Simulation of Dynamic
Voltage Restorer (DVR) to mitigate
voltage sag during three-phase fault.
International conference on electrical
power and energy systems (ICEPES), pp.
14-16.
Priyanka Kumari, Vijay Kumar Garg, JulAug 2013. Simulation of Dynamic
Voltage Restorer using Matlab to enhance
power quality in distribution system.
International Journal of Engineering
Research and Applications (IJERA),
Vol.3, Issue 4, pp. 1436-1441.
. S.Ezhilarasan, G.Balasubramanian,2013.
Dynamic Voltage Restorer For Voltage
Sag Mitigation Using Pi With Fuzzy
Logic Controller. International Journal of
Engineering Research and Applications
(IJERA) Vol. 3, Issue 1, pp. 1090-1095.
Deepa Francis, Tomson Thomas,2014.
Mitigation of voltage sag and swell using
Dynamic
Voltage
Restorer.
In:
International Conference on Magnetics,
Machines & Drives (AICERA-2014
Icmmd).
Sanjay Haribhai Chaudhary, Gaurav
Gangil,
May-Jun-2014.
Analysis,
modeling and simulation of Dynamic
Voltage Restorer (DVR) for compensation
of voltage for sag-swell disturbances.
IOSR Journal of Electrical and
Electronics Engineering (IOSR JEEE),
Vol. 9, Issue 3, pp. 36-41.
Math H.J. Bollen. Understanding Power
Quality Problems Voltage sags and
interruptions. IEEE press.
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Design of Active Shunt Filter for Harmonics Reduction at Load Side for
Power Quality Improvement
Makawana Mukundkumar M., Swapnil Arya
Department of Electrical Engineering, BVM Vallabh Vidyanagar, Anand, Gujarat, India
Corresponding Author: makwanamukund424@gmail.com
ABSTRACT
In the recent years the excessive use of power electronic devices and other non-linear loads in industries
have evolved the problem of power quality deteriorating the power system voltage and current
waveforms by injecting harmonics in the utility supply source. Active harmonic filter helps to overcome
this problem and enhance the power quality. This paper represents the effective solution of power quality
problem by utilizing the shunt active power filter for eliminating the harmonics with the help of
Instantaneous real and reactive power (p-q) theory for generating reference current. The hysteresis
controller is used to get required compensation current to be injected at point of common coupling (PCC).
The simulation is carried out in MATLAB/SIMULINK for the Instantaneous real and reactive power (pq) theory and the results prove the effectiveness of Shunt active power filter for reduction of harmonics
(THD) up to permissible limit and reactive power compensation to maintain power supply quality.
Key words – Power quality, Active shunt filter, Instantaneous reactive power theory, Hysteresis current
control.
I.
INTRODUCTION
The power quality improvement is a major task
nowadays. About 20 years ago, mostly passive
and linear load were used. The usage of nonlinear load was comparatively much lesser thus
it was having negligible impact on power quality
issues. Because of easier controllability of power
electronics and semiconductor device, nonlinear loads like rectifier, choppers and SMPS
etc. are used in every system. The power
electronic devices are very suitable for domestic
use. Due to the use of the power device, the
reactive power disturbances and harmonics
becomes notable in the power network.
The harmonics and reactive power leads to
various problems like distortion of feeder
voltage, overheating of transformers and electric
motors, low power factor, excessive neutral
current, interference with communication
systems. The growing concern of good power
quality and awareness with the harms to power
system due to harmonics along with the penalties
imposed by utility companies and the standards
to the limit of THD made by International
standards concerning electrical power quality
(IEEE- 519, IEC 61000, EN 50160, among
others) impose that electrical equipment and
facilities should not produce harmonic contents
greater than specified values, and also specify
distortion limits to the supply voltage. And also
make it mandatory to solve the harmonic
problems caused by that equipment already
installed.
The purpose of the filter is to reduce the
harmonics from the system and also providing
the reactive power into the system and improve
the power factor. [2] The classification of
harmonic filter is given in Fig. 1.
Harmonic
Filter
Passive
Filter
Active
Filter
Hybrid
Filter
Fig. 1 Classification of harmonic filter
II.SHUNT ACTIVE POWER FILTER
Most of the connection of the active filter is done
in shunt manner, which means that it will behave
as the voltage source and injects the current into
the system.
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Fig. 1 shows the basic compensation principle of
shunt active power filter. A voltage source
inverter (VSI) is used as the shunt active power
filter. ASPF injects a compensating current IF to
the utility, such that it cancels current harmonics
on the AC side i.e. this shunt active power filter
(SAPF) generates the nonlinearities opposite to
the load nonlinearities. Active shunt Filter is
convenient Solutions for Power Quality
Problems such as Current Harmonic Filtering,
Reactive power compensation, Current
unbalance, Voltage Flicker.
Fig. 2 Basic diagrams of ASPF
A.
INSTANTANEOUS PQ THEORY
In this paper simulation carried out for SAPFs
uses p-q theory. The p-q theory is one of several
methods that can be used to generate reference
current for active filters. The p-q theory is a very
efficient and flexible for designing of control
strategies and implementation. [5] So that this
power theory has been largely used in the
implementation of SAPFs over the years, and
has provided good results with different types of
electrical installations and loads. [7]
For p-q theory the electrical grid voltages (Va,
Vb, Vc) and the load currents (ia, Ib, ic) must be
converted to α-β reference frame by applying the
Clarke transformation, given by (1) and (2):
1 1 Va
V
2
2
2 1
. Vb -----(1)
V 3 0
3 3
2
2 Vc
1 1 ia
i
2
2
2 1
. ib ----- (2)
i
0
3
3
3
2
2 ic
The p-q theory power components are calculated
using the expressions (3), where p is the
instantaneous real power, and q is the
instantaneous imaginary power.
p V V I
q V V . I ----- (3)
Each one of the instantaneous power
components can be separated into an average
value and an oscillating value. The physical
meaning of each of the instantaneous powers is:
P - Average value of the instantaneous real
power p.
P῀- Oscillating value of the instantaneous real
power.
q - The instantaneous imaginary power.
The α-β current calculation is done as shown in
equation (4). Then the inverse Clarke
transformation is carried out to find out
reference compensation currents in a-b-c
coordinated as shown in equation (5)
ic
V V P Ploss
1
2
-----(4)
2
ic V V V V q
ica
icb
icc
1
2 1
2
3
1
2
3
ic
2
ic
3
2
0
-----(5)
B.
HYSTERESIS CONTROLLER
Hysteresis current control method can be used to
get required compensation current to be injected
at point of common coupling (PCC). There are
many current control methods, hysteresis current
control method is easily employed and give
quick control of current. The advantages of
hysteresis method are its Robustness and with
minimum hardware it has fastest control.
Disadvantages of hysteresis method are variable
switching frequency. Whenever the current error
fed to it exceeds the fixed band then the switching
operation starts. For better accuracy the band
should be smaller. The switch presents inside the
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upper inverter arm becomes turned off if limit of
current is over reached and that of the switch inside
the lower arm gets turned on if the current limit is
below limit. Now there is a decrease in current.
The working principle is shown below. [3]
Fig. 3 Hysteresis Controller
C.
PI CONTROLLER
The PI Controller is used to regulate constant DC
voltage across the capacitor side of VSI. The DC
voltage remains constant, until the active power
absorbed by the converter decreases to level
where it unable to compensate its losses. Fig. 4
shows PI Controller. The value of Kp and Ki are
tuned by Zicholar Nichols method such that it
generates regulated voltage.
Vdc_ref
P_loss
Ʃ
PI Controller
Vdc
Fig. 4 PI Controller
D.
PARAMETERS OF SAPF
There are two main parameters plays a vital role
in active shunt harmonic filter operation,
1.
Interfacing inductor
2.
DC
link capacitor
1.
Interfacing inductor
The range of the coupling-inductance of an APF
is expressed as eq. (6). [9]
Vdc _ bus
vVdc _ bus
L
-----(6)
8 f s ( Level 1)I r
r I c
When the final value of the inductor is
determined, it is suggested to select a value close
to the lower boundary. The value close to the
lower boundary could provide better current
tracking speed with acceptable current ripples.
The cost of inductor depends on its size. A
smaller inductor reduces the cost. However, it is
suggested to still test the final value by
estimating the upper boundary according to (4).
Sometimes, the upper limit obtained of the
inductor is smaller than the lower limit. It
indicates conflicts exist in the requirement of
current tracking speed and suppressing current
ripple. Some approaches, such as increasing
PWM frequency and adopting multi-level VSI,
could be considered to reduce the lower
boundary.
2.
DC link capacitor
DC side capacitor of voltage source inverter
serves two main purposes [5]:
I.It maintains the DC voltage with small ripples in
steady state.
II.It serves as an energy storage element to supply
a real power difference between load and source
during the transient period.
The power for charging the capacitor is drawn
from the source via antiparallel diode used in
bridge section. [2] The voltage of capacitor is to
maintain to its reference value which is given by
following equation.
2 VLL
Vdc 2
-----(7)
3 m
The size determination of the DC-bus capacitor
is based on the energy balance principle. The
amount of energy is storing in Capacitor is
supplied from the source. The capacitor’s
capacitance can be found out from the energy
storage equation (8).
1
2
2
C DC (VDCref
VDC
) 3V ph aIt -----(8)
2
III.
SIMULATION MODEL AND
RESULTS
A.
Simulation Parameters
Table 1 Simulation Parameters
Supply Voltage
440V, 3 Phase
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B.
Supply Frequency
50Hz
Non-linear Load
100 Ohm.
Coupling Inductor
0.001 H
Dc capacitance
10e-6 F
Simulation Model
shown in fig (7). In this waveform the ASPF is
not connected up to 0.1 second. So during this
period the effect of harmonics are clearly seen.
But after 0.1 second the ASPF is entered in to
the circuit and it makes the waveform very much
sinusoidal. During 0.1 to 0.2 seconds only nonlinear load is connected and after that from 0.2
to 0.3 seconds both linear as well as non-linear
loads are connected to the three phase power
supply.
Fig. 5 MATLAB simulation diagram of ASPF
for p-q Theory
Fig. 7 supply side V and I waveform
Fig. 6 sub circuit for Shunt active power filter
C.
Results
The simulation is carried out using above
parameters and the results are obtained as per
Fig.8 Load side V and I waveform
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Fig. 9 Compensated currents through ASPF for
phase a
IV.
CONCLUSION
The VSI based shunt active power filter is
simulated in MATLAB/Simulink using the
Instantaneous real and reactive power (p-q)
theory. The FFT analysis proves the
effectiveness of shunt active power filter.
Without SAPF the THD in current waveform is
28.98% and after connecting ASPF the THD is
reduced up to 2.27%.
REFERENCES
1.
2.
3.
4.
Hirofumi Akagi, Edson Hirokazu watanabe,
Mauricio Aredes. Instantaneous power
Theory and Application to Power
Conditioning,A John Wiley & Sons, INC.,
Publication.
Dhaval P. Patel, Prof. Swati N. Purohit,
Khoda
N.
Odedra,
Ankit
B.
Patel,2017.Performance of Shunt Active
Power Filter Controlled by Constant Power
Control Technique.In: 3rd International
Conference on Advances in Electrical,
Electronics, Information, Communication
and Bio-Informatics (AEEICB17), IEEE.
Md
Javed,Abinash
Agrawal,
2015.Simulation and Experiments On One
Phase and Three Phase Shunt Active Power
Filters.
PublishedB.Tech.
thesis,Department
of
Electrical
Engineering,
National
Institute
of
Technology, Rourkela.
Wajahat Ullah Khan Tareen, Member, IEEE,
and Saad Mekhielf, Senior Member, IEEE,
2017.Three-Phase Transformerless Shunt
Active Power Filter with Reduced Switch
Count for Harmonic Compensation in Grid-
Connected Applications. IEEE Transactions
on Power Electronics.
5. S. Parthasarathy, S. Rahini, S.A. Karthick
kuma, 2015.Performance Evaluation of
Shunt Active Harmonic Filter Under
Different Control Techniques, International
Conference on Circuit, Power and
Computing Technologies [ICCPCT]
6. S. Shamshul Haq, D. Lenine and S.V.N.L.
Lalitha,2015. Performance Analysis of
Shunt and Hybrid Active Power Filter
Using Different Control Strategies for
Power Quality Improvement, springer
Proceedings of ICECIT.
7. J. G. Pintol, Bruno Expostol, Vi tor
Monteirol, L. F. C. Monteiro, Carlos
Coutol, Joao L. Afonsol,2012.Comparison
of Current-Source and Voltage-Source
Shunt Active Power Filters for Harmonic
Compensation and Reactive Power Control.
In:IECON - 38th Annual Conference on
IEEE Industrial Electronics Society, pp
5161 – 5166.
8. Balaga UdayaSri, P.A.Mohan Rao,
Dasumanta Kumar Mohanta, M. Pradeep
Chandra Varma,2016.Improvement of
power quality using PQ-theoryshunt-active
power filter.International conference on
Signal Processing, Communication, Power
and Embedded System (SCOPES).
9. Ning-Yi
Dai,
Man-Chung
Wong,2011.Design Considerations of
Coupling Inductance forActive Power
Filters.In: 6th IEEE Conference on
Industrial Electronics and Applications.
10. Hirofumi Akagi, Akira Nabae. Control
Strategy of Active Power Filters Using
Multiple Voltage-Source PWM Converters,
IEEE.
11. J. G. Pintol, Bruno Exposto, Vi tor
Monteiro, L. F. C. Monteiro, Carlos Coutol,
Joao L. Afonsol, 2012.Comparison of
Current-Source and Voltage-Source Shunt
Active
Power Filters for Harmonic
Compensation and Reactive
Power
Control, IEEE.
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A Study on Speed Control of BLDC Motor Using Fuzzy Logic
Kerulkumar R Chaudhari, Akshay A. Pandya
Department of. Electrical Engineering, BVM Engg College, Vallabh Vidhyanagar, Gujarat
Corresponding Author: kerulchaudhari11@gmail.com
ABSTRACT
Due to the properties like high efficiency, reliability, high starting torque, less electrical noise and high
weight to torque, Brushless DC Motor (BLDCM) has been used widely in industries. Importance of the
speed controls of BLDCM is highly required because it indirectly controls efficiency by the mechanical
output required. Controllers such as PWM, PI, Fuzzy and Neural Networks (NN) are used to control the
parameter related to speed. This paper work deals with FLC design by using a simple analogy within the
control surfaces of the FLC and a PI controller for the same. MATLAB / SIMULINK package program
has been used for the simulation and analysis of model. Also, various study shows that the FLC offers
better adaptability than conventional PI controller and due to this the BLDCM drive offers better steady
state and dynamic performances.
Keywords: BLDC Motor, Speed Control, PI Controller, FLC
structure and ease of implementation; PI
I.
INTRODUCTION
controllers are widely used in the industrial
sector. These controllers at the same time pose
Nowadays the use of BLDC motor instead of
some difficulties such as control complexity
brushed DC motor has increased in number of
nonlinearity, load disturbances and parametric
power electric drive applications. BLDC motor
variations.
comprise of sinusoidal (PMSM) or trapezoidal
The use of faster dynamic response controller in
(PM BLDC) motor, depending u1pon the
motion control like Artificial Intelligence (AI),
rotational voltage (back EMF) induced. Due to
Adaptive Neuro Fuzzy Inference Systems
the fact of recent advancements in technology,
(ANFIS); is the substitution of a standard (PI)
these motors which are categorized as special
controller. FLC speed controller is one the
electrical motors are much more suitable for
frequently accessed controller used for the speed
efficient drive operation. These motors are
control of an electric drive. Fuzzy logic speed
characterized by a much higher efficiency,
control can sometime be seen as the ultimate
greater reliability, and more power density
solution for high-performance electrical drives.
requiring less maintenance. Due to the fact that
PI controller when compared with these recent
PM BLDC has higher torque delivered to motor
emerging controllers, found to be comparatively
size ratio, high efficiency and long life; these
inefficient. The reason for low efficiency in the
motors find their application in various electrical
PI controller is the high overshoot from the
systems depending upon the requirements. In
reference point, which leads to transients and
this context it can also be noticed that from last
large delay time to get into steady state. The slow
few years, research in this area have experienced
response on the sudden change of load torque
an expansion.
and the sensitivity to controller gains (Kp and
The desired level of performance from BLDC
Kc) are the other reasons for the obsoleteness of
motor could be achieved by the use of suitable
PI controllers. This has resulted in the increased
speed controllers in the overall electric drivedemand of modern nonlinear control structures
system. Many controllers like PI, FLC and NN
like Fuzzy logic controller. These controllers are
are available for the speed control of such
inherently robust to load disturbances. BLDC
electric drives. The Proportional plus Integral
motors being non-linear in nature can easily be
(PI) controller; is the most commonly used
affected by the parameter variations and load
standard controller applicable for speed control
disturbances.
of electrical drives. Due to the simple control
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II.
CONSTRUCTION
AND
PRINCIPLE OF OPERATION
Brushless motor is considered to be an
electronically commutated motor. It requires
electrical switches for realizing commutation of
current and hence motor is rotated continuously.
These switches are connected in H-bridge
structure. Figure 1 shows BLDC connected to
driver circuit.
Figure 1: BLDC motor with driver circuit
Three hall sensors are required for a three phase
BLDC motor which is used to detect the position
of rotor. Three sensors are placed on stator at
120-degree intervals. These windings are placed
in a star formation. Each hall sensors changes its
state for every 60-degree rotation and completes
the whole cycle by taking six steps. Rotor pole
pairs are used to determine number of cycles
required to complete a mechanical rotation.
Hence, number of cycles is same as rotor pole
pairs.
III. BLDC
CONTROLLERS
SPEED
There are several controllers available nowadays
like proportional integral (PI), proportional
integral derivative (PID) Fuzzy Logic Controller
(FLC) or the combination between them: FuzzyNeural Networks, Fuzzy Genetic Algorithm,
Fuzzy-Ants Colony, Fuzzy-Swarm. But as
within the scope of this paper the discussion on
the PI and Fuzzy Logic Controller will be
discussed as below.
A.
PI Speed Controller
A Proportional Integral (PI) is a feedback
control loop mechanism used in electrical
control system. PI Controller finds its
applications in many industrial processes where
a controller attempts to correct the error between
a measured process variable and reference set
point. The algorithm involves a calculation and
outputting of a corrective action which is done
in order to adjust the process accordingly. The PI
controller, as the name indicates, involves two
separate modes that are: the proportional mode
and integral mode. The proportional mode
determines the reaction to the current error
whereas the integral mode determines the
reaction based recent error. Due to its simple
structure and ease of use; PI controller is widely
used in industry. The speed of the motor is
compared with its reference value and the speed
error is processed in proportional integral (PI)
speed controller.
B.
Fuzzy Logic based Speed Controller
Non-Linear Systems can be very easily
modeled by Fuzzy Logic Controller (FLC). The
conventional control system design is usually
based on the mathematical model of plant which
is generally complex mathematical equations.
On the other hand, FLC expresses operational
laws in terms of linguistics terms instead of
mathematical equations. Sometimes it has been
experienced that there are many systems which
are too complex to model accurately, even with
complex mathematical equations; therefore,
conventional methods become infeasible in
these systems. Henceforth, fuzzy logics
linguistic terms provide a feasible and easy
method
for
defining
the
operational
characteristics of such system to design and
implement.
The generalized block diagram of a BLDC
Motor with a controller as shown in Fig. 2, can
be replaced by any other controller as required.
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Any control mechanism can be adopted in the
system such as PI, PID or Fuzzy Logic
Controller which will be suitable to maintain and
control the speed of the BLDC Motor.
Inputs are error (e) and change in error (ce).
Difference of reference speed (ωref) and the
original speed (ω) gives the speed error. Output
voltage is the controller output.
Membership function chosen is the triangular
shaped function because of its simplicity and
good controlling operation. Error, change in
error and output voltage is the membership
function used here. Seven level of membership
function are applied for all the variables.
IV.
Figure 2: Block Diagram of a BLDC Motor
with Controller Scheme
The section ahead explains the Simulink model
of a BLDC Motor with a PI and a Fuzzy Logic
Controller along with the simulations results
which is discussed. FLC is an algorithm which
is dependent on lingual strategy of control. It
acquires human thinking about controlling the
systems without mathematical modeling. Fuzzy
logic’s lingual terminology is often exhibited
using some of the logical insinuation like IfThen rules. These logical rules describe a scale
of values which is known as fuzzy membership
function. Block diagram of fuzzy logic
controller is given below,
Figure 3: Fuzzy controller block diagram
There are two types of fuzzy logic controller.
They are Sugeno Takagi architecture and
Mamdani architecture. For controlling speed,
Mamdani architecture of fuzzy logic is used.
SIMULATION
Simulink model of a Permanent magnet BLDC
Motor with the FLC is designed in a MATLAB
Simulink tool. The Simulink model consists of a
3phase supply via inverter and a BLDC motor.
The model is coupled with a FLC for the speed
control of the motor. The model has been
designed using the following parameters as
shown in Table I.
Table 1: PARAMETERS CHART
Speed (N in RPM)
1500
Voltage (Vin volts)
Poles of the Motor
(P)
160
Motor phases (ф)
Stator Phase
Resistance (Rs in
ohm)
3
0.7
Torque Constant (k)
0.84
Load Torque
Back EMF area
(degree)
Rotor Initial Position
(Ө in degrees )
Kp=Proportional
Constant
2 N-m
Ki=Integral Constant
5
4
120
0
0.002
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order to keep the current within a certain range
for a specific speed, could be a work for future.
The proposed future work would thereby
enhance the motor start-up current, reduce the
motor current ripples and overall enhance the
motor torque characteristics performance.
Current control methodology will also reduce
the speed and torque variations caused due to
any sudden changes in the motor current value.
REFERENCE
1.
2.
3.
4.
Figure 4: Simulation Model of the Speed
Control of BLDC using FLC
Fig. 4 shows the PM BLDC Simulink model
with a FLC and the simulation results for the
same have been shown ahead. The simulations
results comprise of speed, torque and current
characteristic curve of a BLDC motor with FLC.
V.
CONCLUSIONS
The speed control of a Permanent Magnet BLDC
Motor is studied in this paper, using both PI
controller, and Fuzzy Logic Controller. The
paper explains about the performance analysis of
a BLDC Motor in brief Further a comparative
study has been discussed between the PI
controller and Fuzzy Logic controller used on
the MATLAB Simulink tool for the speed
control of a BLDC motor. The inference which
can be concluded after comparison is that speed
control of BLDC using Fuzzy Logic Controller
has better performance. To add current control
function to the proposed speed controller in
5.
6.
7.
Tan Chee Siong, Baharuddin Ismail 2010.
Study of fuzzy and pi controller for
permanent-magnet brushless dc motor drive
Adil Usman and Bharat Singh Rajpurohit
2016. Speed Control of a BLDC Motor
using Fuzzy Logic Controller
Shruti 2016. Speed Control of BLDC using
Fuzzy Logic
W. Hong, W. Lee and B. K. Lee 2007.
Dynamic Simulation of Brushless DC
Motor
Drives
Considering
Phase
Commutation for Automotive Applications
S. Rambabu 2007. Modeling and control of
a brushless DC motor
M.Harith, K. P. Remya, Kalady ASIET, and
S. Gomathy 2015. Speed Control of Brush
less DC Motor Using Fuzzy Based
Controllers
Muhammad Firdaus Zainal Abidin,
Dahaman Ishak, and Anwar Hasni Abu
Hassan 2011. International Conference on
Computer Applications and Industrial
Electronics
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Hybrid Energy Management System design with Renewable Energy
Sources (Fuel Cells, PV Cells and Wind Energy): A Review
Seema Agrawal, Seemant Chourasiya, D.K. Palwalia
Corresponding Author: Seema10dec@gmail.com
Abstract
This paper presents a novel adaptive scheme for energy management in stand-alone hybrid power
systems. The proposed management system is designed to manage the power flow between the hybrid
power system and energy storage elements in order to satisfy the load requirements based on artificial
neural network (ANN) and fuzzy logic controllers. The neural network controller is employed to achieve
the maximum power point (MPP) for different types of photovoltaic (PV) panels, based on Levenberg
Marquardt learning algorithm. The statistical analysis of the results indicates that the R2 value for the
testing set was 0.99.The advance fuzzy logic controller is developed to distribute the power among the
hybrid system and to manage the charge and discharge current flow for performance optimization. The
developed management system performance was assessed using a hybrid system comprises PV panels,
wind turbine, battery storage, and proton exchange membrane fuel cell (PEMFC). To improve the
generating performance of the PEMFC and prolong its life, stack temperature is controlled by a fuzzy
logic controller. Moreover, perturb and observe (P&O) algorithm with two different controller techniques
the linear PI and the nonlinear passivity based controller (PBC) are provided for a comparison with the
proposed MPPT controller system. The comparison revealed the robustness of the proposed PV control
system for solar irradiance and load resistance changes. Real time measured parameters and practical
load profiles are used as inputs for the developed management system. The proposed model and its
control strategy offer a proper tool for optimizing the hybrid power system performance, such as the one
used in smart house applications. The research work also led to a new approach in monitoring PV power
stations. The monitoring system enables system degradation early detection by calculating the residual
difference between the model predicted and the actual measured power parameters. Measurements were
taken over 21 month’s periods; using hourly average irradiance and cell temperature. Good agreement
was achieved between the theoretical simulation and the real time measurement taken the online grid
connected solar power plant.
I.
INTRODUCTION
Therefore, a solar-wind hybrid power system
model will be presented [1-3]. The system will
consist of
a) PV panels, to convert the sunlight into direct
current,
b) wind turbine, to convert the kinetic energy
from the wind into mechanical energy,
c) DC generator, to convert the mechanical
energy from the turbine into electrical energy,
d) MPPT, to operate the PV at the maximum
power point (MPP),
e) fuel cells, which performs as a backup power
source,
f) battery bank, to supply energy to the system
when is needed and store it when is not
needed,
g) DC/DC converters, to steps-up the voltage to
a higher DC voltage,
h) DC/AC inverters, to generate AC waveform
from the DC signal, (i) main controller, to
ensure the continuous power supply for the
load demand. A schematic diagram of a basic
hybrid system is shown in Figure 1.
II.
Hybrid Power System: Modeling &
Simulation
In power applications and system design,
modeling and simulation are essential to
optimize control and enhance system operations.
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The dynamic simulation model is described for
a hybrid power system comprises PV panels,
wind turbine, fuel cells, battery bank, converters
and controllers.
Fig.1- Block diagram of a hybrid power
generation system
The main controller will have developed to
ensure the continuous power supply for the load
demand [4-5]. The following subsections
present the implementation of the PV/wind
turbine/ PEMFC/Li-Ion battery system model
[6]. Modeling and simulation are implemented
using MATLAB/ Simulink and Sim Power
System software packages. The block diagram
of the developed hybrid power system is shown
in Figure 2.
A. The photovoltaic model
A model of PV panel with moderate complexity
which includes the series resistance, the
saturation current of the diode, and the
temperature independence of the photocurrent
source is considered based on the Shockley
diode equation. The PV model is built and
implemented using Simulink to verify the
nonlinear I–V and P–V output characteristics
[7]. Each function uses a notation with a
meaningful lettering to make it readable and
maintainable; e.g. reverse saturation current
function stands for the implementation of
Equation (1).
𝐼 =
(1)
Where Ioα is the cell’s reverse saturation current
at a solar radiation and reference temperature; voc
is the cells open circuit voltage. The cell ideal
factor (F) is dependent on the cell technology.
The inputs for the proposed PV model are solar
irradiation, cell temperature and PV
manufacturing data sheet information. In this
chapter, ADT 12AS PV module is taken as an
example. The proposed PV model was simulated
using MATLAB/Simulink, [8] as shown in
Figure 3.
Fig.3 - Implementation of the PV model
Fig. 2 - Block diagram of the developed hybrid
power system
B. The wind turbine model
The amount of power that a wind turbine can
extract from the wind depends on the turbine
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design. Factors such as the wind speed and the
rotor diameter affect the amount of power that a
turbine can extract from the wind. The wind
turbine was modelled using the mathematical
equations [2].
𝑃 = 𝜌𝐴 𝑉
(2)
Where ρ is the air density in (kg/m3), AS is the
swept area of blades (m²), v is the wind speed
(m/s). As illustrated, there are three inputs and
one output. The three inputs are the generator
speed, the pitch angle, and the wind speed. The
output is the torque applied to the generator
shaft. The built-in Sim Power System block
model of a DC machine is used as a power
generator driven by the wind turbine (Math
Works 2012). As shown in Figure 6, the rotor
shaft is driven by the wind turbine which
produces the mechanical torque according to the
generator and wind speed values [10].
Fig. 6 – Implementation of the wind turbine DC
generator model
A Proportional Integral (PI) controller is used to
control the blade pitch angle in order to limit the
electric output power to the nominal mechanical
power [11].
C. The Li-Ion battery model
The model of the Li-Ion battery is implemented
in MATLAB/Simulink based on the
mathematical
𝑄
𝑄
𝑖𝑡 − 𝑅 − 𝐾
𝑖∗
𝑄 − 𝑖𝑡
𝑖𝑡 + 0.1𝑄
+ 𝐴𝑒𝑥𝑝(−𝐵 𝑖𝑡)
Where EO is the battery constant voltage (V), K
is the polarization constant (Ah-1), Q is the
maximum battery capacity (Ah), it (∫ i dt) is the
actual battery charge (Ah), R is the internal
resistance (Ω), i is the battery current (A), i* is
the low frequency current dynamics (A), A is the
exponential zone amplitude (voltage drop during
the exponential zone) (V), and B is the
exponential zone time constant inverse (Ah) −1.
It is implemented using several standard
Simulink blocks as well as some of the Sim
Power System blocks as shown in Figure 7. The
output of this model is a vector containing three
signals: state-of-charge (SOC), battery current
and battery voltage [12].
𝑉
= 𝐸 −𝐾
Fig. 7 - Subsystem implementation of the LiIon battery model
The main feature of this battery model is that the
parameters can easily be deduced from a
manufacturer’s discharge curve.
D. The PEMFC stack model
The fuel cell stack voltage (Vfc) is described as
𝑉 = 𝐸
− 𝑁𝐴𝑙𝑛
×
−𝑅
𝐼
Where Eoc is the open circuit voltage (V), N is
the number of cells, A is the Tafel slope (V), Io
is the exchange current (A), Ifc is the fuel cell
current (A), Td is the response time (sec), and
Rohm is the internal resistance (Ω). The dynamic
model of PEMFC is built and implemented using
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MATLAB/Simulink. The modified fuel cell
model combines the features of chemical [13]
and electrical models [14]. Hence, it’s suitable
for electrical simulation programs and can
represent the effect of operating parameters on
the stack. The model is implemented as shown
in Figure 8. Fuel cell manufacturers provide
specifications of their stacks which include the
peak power, polarization curve, number of cell,
etc. The PEMFC stack model is modified to
include a fuzzy logic temperature controller are
used to obtain the models parameters.
III.
Fig. 8 - Subsystem implementation of the
PEMFC stack model
Hybrid Systems Energy Controller Based on
Artificial Intelligence
A novel adaptive scheme for energy
management in stand-alone hybrid power
systems, the proposed management system is
designed to manage the power flow between the
hybrid power system and energy storage
elements in order to satisfy the load
requirements based on artificial neural network
(ANN) and fuzzy logic controllers [15]. The
method offers an on-line energy management by
a hierarchical controller between four energy
sources comprises photovoltaic panels, wind
turbine, battery storage, and proton exchange
membrane fuel cell [16]. The proposed method
includes a MPPT controller in the first layer, to
achieve the maximum power point (MPP) for
different types of PV panels; two different
techniques will be presented (P&O and neural
network). In the second layer, an advance fuzzy
logic controller will be developed to distribute
the power among the hybrid system [17] and to
manage the charge and discharge current flow
for performance optimization. Finally in the
third layer, smart controllers are developed to
maintain the stability of the PEMFC temperature
and to regulate the fuel cell/battery set points to
reach best performance [18]. Figure 9 shows the
proposed control structure for the hybrid
generation system.
Fig. 9 - Block diagram of the proposed system
IV.
Simulation Discussion
The dynamics simulation models for each of the:
PV array, wind turbine, PEM fuel cell, and LiIon battery were explained and shown.
Afterward, an optimized energy management
[19-22] based on a hierarchical controller has
been implemented to satisfy important
objectives such as: optimal operation of PV
panel, battery charge balance, optimal operation
of FC, and load. Here, P&O algorithm with
linear and non-linear controllers are provided for
a comparison with the proposed MPPT
controller system [23-29].
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V.
Conclusion
[9]
The analysis of simulation results has shown that
the adaptive algorithm developed is suitable for
stand-alone hybrid power systems. This control
[10]
algorithm is capable of:
Extracting maximum power from the PV panels
with tracking efficiency exceed 94.5%.
Splitting the power between the power sources [11]
to sustain the efficiency of the system.
Regulating the PEMFC on/off status according
to external environmental changes and to load [12]
demand expectation
Optimizing the generating performance of the
PEMFC by maintaining the temperature stable
and equal to the stack operating temperature
(e.g. 65%).
[13]
References
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
N. Shaheen, N. Javaid, Z. Iqbal, K. Muhammad, K. Azad
and F. A. Chaudhry, "A Hybrid Algorithm for Energy
Management in Smart Grid," Network-Based Information
Systems (NBiS), 2015 IEEE 18th International
Conference on, Taipei, 2015, pp. 58-63.
Ahmed, N.A., Al-Othman, A.K., & Al-Rashidi, M.R.
(2011) Development of an Efficient Utility Interactive
Combined Wind/Photovoltaic/Fuel Cell Power System
with MPPT and DC Bus Voltage Regulation, Electric
Power Systems Research, 81, (5), pp. 1096–1106
Ahmed, N.A., Miyatake, M., & Al-Othman, A.K. (2008)
Power Fluctuations Suppression of Standalone Hybrid
Generation Combining Solar PV/Wind Turbine and Fuel
Cell Systems, Energy Conversion and Management, 49,
(10), pp. 2711-2719.
Hau, E. (2006). Wind Turbines: Fundamentals,
Technologies, Application, Economics, 2nd edn. Springer,
Berlin, Germany.
Hwas, A., & Katebi, R. (2012) Wind Turbine Control
using PI Pitch Angle Controller, IFAC Conference on
Advances in PID Control, Brescia, Italy.
Muljadi. E., & Butterfield, C.P. (2001) Pitch-Controlled
Variable Speed Wind Turbine Generation, IEEE Trans.
Industry Applications, 37, (1), pp. 240– 246.
Borowy, B.S., & Salameh, Z.M. (1996) Methodology for
Optimally Sizing the Combination of a Battery Bank and
PV Array in a Wind/PV Hybrid System, IEEE Trans.
Energy Conversion, 11, (2), pp. 367–373.
Qiuli, Y., Srivastava, A.K., Choe, S.-Y., Gao, W. (2006)
Improved Modeling and Control of a PEM Fuel Cell
[14]
[15]
[16]
[17]
[18]
[19]
Power System for Vehicles, Southeast Con, 2006.
Proceedings of the IEEE, pp. 331 – 336
Souleman, N.M., Tremblay, O., & Dessaint, L.-A. (2009)
A Generic Fuel Cell Model for the Simulation of Fuel Cell
Power Systems, IEEE Power & Energy Society General
Meeting, pp. 1-8.
Natsheh, E.M., & Albarbar, A. (2013) Hybrid Power
Systems Energy Controller Based on Neural Network and
Fuzzy Logic, Smart Grid and Renewable Energy, 4, (2),
pp. 187-197.
Wang, C., & Nehrir, M.H. (2008) Power Management of
a Stand-alone Wind/PV/Fuel Cell Energy System. IEEE
Trans. Energy Conversion, 23, (3), pp. 957-967.
Esram, T., Urbana, I.L., Chapman, P.L. (2007)
Comparison of Photovoltaic Array Maximum Power Point
Tracking Techniques, IEEE Trans. Energy Conversion,
22, (2), pp. 439 – 449. Celik, A.N. (2003) TechnoEconomic Analysis of Autonomous PV–Wind Hybrid
Energy Systems using Different Sizing Methods, Energy
Conversion and Management, 44, (12), pp. 1951-1968.
Das, D., Esmaili, R., Longya, X., & Nichols, D. (2005) An
Optimal Design of a Grid Connected Hybrid
Wind/Photovoltaic/Fuel Cell System for Distributed
Energy Production, 31st Annual Conference of IEEE,
Industrial Electronics Society, Raleigh, NC.
Dursun, E., & Kilic, O. (2012) Comparative Evaluation of
Different Power Management Strategies of a Standalone
PV/Wind/PEMFC Hybrid Power System, Electrical
Power and Energy Systems, 34, (1), pp. 81-89.
Kim, S.K., Jeon, J.H., Cho, C.H., Kim, E.S., & Ahn, J.B.
(2009) Modeling and Simulation of a Grid-Connected PV
Generation System for Electromagnetic Transient
Analysis, Solar Energy, 83, (5), pp. 664- 678.
Villalva, M.G., Gazoli, J.R., & Filho, E.R. (2009)
Comprehensive Approach to Modeling and Simulation of
Photovoltaic Arrays, IEEE Trans. Power Electronics, 24,
(5). pp 1198–1208.
Hajizadeh, A., & Golkar, M.A. (2007) Intelligent Power
Management Strategy of Hybrid Distributed Generation
System. International Journal of Electrical Power &
Energy Systems, 29, (10), pp. 783–795.
Kim, M., Sohn, Y.-J., Lee, W.-Y., & Kim, C.-S. (2008)
Fuzzy Control Based Engine Sizing Optimization for a
Fuel Cell/Battery Hybrid Mini-Bus. Journal of Power
Sources, 178, (2), pp. 706-710.
C. H. Cai, D. Du and Z. Y. Liu, "Battery state-of-charge
(SOC) estimation using adaptive neuro-fuzzy inference
system (ANFIS)," Fuzzy Systems, 2003. FUZZ '03. The
12th IEEE International Conference on, 2003, pp. 10681073 vol.2.
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Comparative study of ATSMC and PTMC for a Single Phase SAPF
Seema Agarwal*1, Seemant Chourasiya*2 , D. K. Palwalia*3,
Department of Electrical Engineering, Rajasthan Technical University, Kota, INDIA
Corresponding Author: seema10dec@gmail.com
Abstract
This paper describes the analysis, design, simulation and comparison of the Precise Total
Multivariable Control (PTMC) theory and Adaptive Total Sliding Mode Controller (ATSMC) to a
single phase shunt dynamic power filter(SPSDPF) to enhance the power quality by reducing harmonic
distortions of electrical system. The aim of this paper is to show the comparison of the PTMC and
ATSMC theory and find out which theory is better for the reduction of harmonics. These controllers
are implemented and designed in MATLAB 2012a. MATLAB/SIMULINK Results are provided in
MATLAB 2012a.
Keywords:- Precise Total Multivariable Control, Adaptive Total Sliding Mode Controller, Shunt
dynamic power filter, Harmonic Elimination.
INTRODUCTION
Nowadays the use of non-linear load is increased
rapidly in industry and in electronic equipment.
All the power electronic devices are considered
as nonlinear load. Television, Refrigerator, Air
Conditioner, Inverters, Printers, Fax machines
are some example of non-linear load [1].
Increased use of non-linear load has increased
the amount of distorted currents on electrical
system. Therefore, interest has been shown as to
the effect of power factor and the extent of
harmonics currents being generated and injected
in power lines.
Traditionally, passive filters have been used to
compensate voltage and current harmonics
generated by constant non-linear loads. Passive
power filters provide low impedance path for
distorting harmonics in voltage and current,
resulting in improvement of power quality.
Passive filters can be easily designed and have
low cost. However, there are some drawbacks of
passive filters such as mistuning, resonance,
bulky implementation, no possibility of using
same power filter for different load. [2]-[3].
These drawbacks of passive filters can be
overcome by use of active power filters.
Several control topologies functioning with
power semiconductor switches have been
developed for high-quality requirement. These
topologies are designed to call off the original
voltage and current harmonics deformation by
injecting the same detected deformation, but
with reverse polarity, thereby recuperating the
power quality. Active power filters are
connected between source and load. Depending
I.
upon the type of connection it can be classified
as series dynamic power filter, shunt dynamic
power filter and hybrid dynamic power filter.
Shunt active power filters are most widely used
solution to reduce current harmonics, while
series active power filters are used to reduce
voltage harmonics. Universal active power
filters are used current harmonics as well as
voltage harmonics. Shunt active power filters are
usually applied to three phase systems whereas
single phase active filters can be applied in
adjustable speed motor drive.
Different control methods have been reported to
control shunt active power filters. These can be
classified as:
1. Time-Domain Control Techniques
2. Frequency-Domain Control Techniques Both
time-domain and frequency-domain control
techniques have well-known disadvantages as
these provide non-linear dynamics of the
closed loop system.
Also, some advance control methods have been
reported, such as sliding mode control, artificial
neural networks, and optimization [4]- [9]. Of
the above-mentioned control methods, the
sliding mode control have been extensively
applied to the power converters because it has
natural tendency to control time varying
topologies. Sliding mode control is the nonlinear control strategy.
The principle for applying sliding mode control
strategy is to propose a sliding surface or
switching function. Sliding mode control has
inherent characteristics such as insensitivity to
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system parameters variation, robustness and
simple control implementation. In this study,
sliding mode control (SMC) is proposed which
leads to sliding surface which is linear
combination of system state variables and the
generated references. This control design results
in sliding mode controller, which makes the
system robust, insensitive to system parameter
variation and simple implementation.
Further, PTMC is proposed using sliding mode
controller which simplifies the procedure to
convert non-linear system to normal system. The
comparison of ATSMC with PTMC is shown in
this work.
II. STUDY OF ADAPTIVE TOTAL
SLIDING MODE CONTROLLER
The main aim of this part of paper is to present
an efficient design, mathematical analysis of
shunt dynamic power filter and design of
Adaptive Total Sliding Mode Controller
A. Active Mathematical Modelling of shunt
dynamic power filter
To analyze the operational mode of shunt
dynamic power filter, we define a switching
function represented as:
1 if T is ON
0 if T is OFF
Here ‘i’ can be given values from (1 to 4) each
representing the switch number. The two
switches from the similar segment of the
dynamic power filter must operate harmonizing.
Therefore, we can write:
U + U = 1 and U + U = 1
(1)
v = (U + U − 1)V
(3)
The current curving through filter capacitor (IC)
can be written as:
I = (U + U − 1) × I
(4)
From expressions of vx (3) and IC (4), the
dynamic state equations for the inductor current
and capacitor voltage are as given below:
L
= 𝑉 − 𝐼 𝑅 − (𝑈 + 𝑈 − 1)𝑉
(5)
C
= (U + U − 1)I
(6)
Here VS is the source voltage.
Let U + U − 1 = U, the dynamic state model
of shunt active power filter becomes:
= (V − I R − UV )
(7)
= UI
(8)
U =
Fig.1. Shunt dynamic power filter
v = (U U − U U )V
(2)
From equation (1) and (2) we get
Fig.2. Block Diagram of Shunt dynamic power
filter
Fig.3. Sliding surface (a) Stable system (b)
Unstable system
B. Adaptive Total Sliding Mode Control Strategy
The controller consists of two control loops.
Outer voltage loop regulates the capacitor
voltage and inner current loop tracks the
reference current signal. To control the DC
capacitor voltage PI controller is used and
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inductor current is controlled by the use of
Sliding Mode control strategy.
The performance of the controller is improved
by proposing a control algorithm based on
sliding surface which depends on source current
(IS). Assume (VDC, IS) be the reference values of
filter capacitor voltage and source current. The
reference values assumed above are also known
as equilibrium points of the control system. Now
we calculate the error signal or error function
𝑒 = 𝐼 − 𝐼 ∗ = 0 which represents the sliding
surface. Also, it is found that system has steady
state current error. So as to minimize the steady
state error an integral term is introduced given by
𝑒 = ∫ 𝑒 . 𝑑𝑡.
The proposed sliding surface or sliding function
is given by:
S = e + λe Or S = e + λ ∫ e
(9)
Where 𝜆 is a control parameter also known as
sliding coefficient? Positive values of sliding
surface coefficient (𝜆) ensures stability of active
power filter. After deriving the sliding mode
surface, now our aim is to define the control law
based on three conditions. These conditions are
as follows Reaching Condition, Existing
Condition, Stability Condition. The inequality
which satisfies the existing and reaching
condition of the system is given by:
dS
lim S.
<0
→
dt
C. Controller Design and Reference Current
Calculation
In SM controller in order to satisfy the existence
condition we usually determine as following:
1 if
S>0
U = 0 if
S=0
−1 if S < 0
applying the control law given in equation 4.
Switches of one leg of APF (T3,T4) operates at
source voltage frequency and that of other
leg(T1,T2)operate at high frequency. The control
algorithm U makes the state trajectory to reach
the sliding surface in finite time and then slides
along the surface towards equilibrium point
exponentially. The complete analogy SM
controller for single phase shunt APF is shown
in fig. 4.
Fundamental component of the gate pulses to
switch is in same phase to that of source voltage
(Vs). So a band pass filter can be used to generate
the fundamental component of gate pulse by
filtering its harmonics. The characteristics of
band pass filter have a significant effect on the
active power filter performance. The bandwidth
should be small enough to sufficiently attenuate
the harmonic components of the reference
current.
The capacitor voltage is put through a RC low
pass filter which yields the average capacitor
voltage. This quantity is compared to the
reference capacitor voltage, with the difference
driving the PI controller. The output of the PI
controller is a slow varying variable which is the
peak value of reference source current. This
implies that the output of PI controller gives sum
of peak value of fundamental load current and
the peak value of source current required to
compensate the real power loss in filter
capacitor. As a result, this slow varying variable
is multiplied with the output of band pass filter
to generate the desired reference source current.
As band pass filter is used to calculate reference
current, small variation in amplitude of source
voltage does not affect reference source current.
This is why this active filter is applicable for
both distorted and nominal source.
III. STUDY OF PRECISE TOTAL
MULTIVARAIBLE CONTROL THEORY
VIA SLIDING MODE CONTROL
The main motive of this segment is to present an
efficient design procedure of precise total
multivariable control law by combining it with
sliding mode control theory to get better results.
Fig. 4. Adaptive total sliding mode controller for A. Multivariable linearization:
shunt apf
In multivariable linearization non-linear
The sign of should be controlled to satisfy the
characteristics of the electrical system is
transformed into a linear characteristics and then
existence condition. This can be done by
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linear control techniques are used to control the B. Control Design:
whole non-linear electrical system.
The stability of the electrical system is
Taking into consideration a non-linear singleconformed if the coefficients K1 and K2 of the
input single-output (SISO) electrical system
sliding surface are always positive and greater
.
than zero. The system has following dynamics:
x f ( x ) g ( x ).U
𝑒̈ + 𝐾 . 𝑒̇ + 𝐾 . 𝑒 = 0
(16)
𝑌 = ℎ(𝑥)
This is exponentially stable if the requirements
Where f(x) and g(x) defines smooth vector fields
𝐾 , 𝐾 ≥ 0 are accomplished.
on Rn, h(x) defines smooth function, Y is system
Considering the main function of the shunt
output and U is the control input variable.
active power filter is to shape the line current to
Relative degree is a very important theoretical
be in same phase as the line voltage. Desired
concept in input-output linearization which is
behaviour of the line current can be derived as
interrelated to the numeral of epoch the system
follows
output Y to be differentiated, for the
𝑖
= 𝑘. 𝑣
input to be appear in the output equation
(17)
𝑌̇ = ∇ℎ(𝑓 + 𝑔. 𝑈) = 𝐿 ℎ(𝑥 ) + 𝐿 ℎ(𝑥 ). 𝑈
where k is output of PI controller and sluggish
(11)
time varying factor based on power demand.
Where L h(x) and L h(x) are the Lie algebra
By the correlation between line current, filter
current and load currents, we can derive the
derivatives of h(x) with reverence to
current reference expression as
f(x) and g(x) . If the virtual degree r of the
𝑖 ∗ = 𝑘. 𝑣 − 𝑖
electrical system coincides with the system order
(18)
(r=n), we must differentiate r times the system
Hence, we can write the expression of error
output, i.e.
function as:
𝑌 = 𝐿 ℎ(𝑥 ) 𝑓𝑜𝑟 𝑎𝑙𝑙 𝑘 < 𝑟 − 1
𝑒 = ∫ 𝑣 (𝑖 − 𝑘𝑣 )𝜕𝑟
(12)
(19)
and
from
the above equation the sliding surface
𝑌 = 𝐿 ℎ (𝑥 ) + 𝐿 𝐿 ℎ(𝑥 ). 𝑈
can be
derived as:
(13)
Which shows that 𝐿 𝐿 ℎ (𝑥 ) = 0 for all (k < r-1)
𝑠 = 𝑣 (𝑖 − 𝑘𝑣 ) + 𝐾
𝑣 (𝑖 − 𝑘𝑣 )𝜕𝜏
and 𝐿 𝐿 ℎ(𝑥 ) ≠ 0 𝑓𝑜𝑟 (𝑟 = 𝑛). Hence the
+ 𝐾
𝑣 (𝑖
system linearization can be done by means of the
subsequent input conversion.
− 𝑘𝑣 )𝜕𝜏
(20)
𝑈=
[𝑣
−
𝐿
ℎ(𝑥)]
( )
The key aim in derivation of sliding mode
(14)
controller is to fulfil the reaching surface
which provides a linear bond linking the
condition which ensures the existence of the
electrical system output Y and the control input
sliding regime on a sliding surface. The reaching
𝑣:
surface condition can be given by:
𝑦 = 𝑣
𝑠. 𝑠̇ < 0
(15)
The control law is obtained as
Still, the electrical system cannot be liberalized
1, for 𝑠 > 0
𝑈=
when the virtual degree of an electrical system is
0, for 𝑠 < 0
not more than the order of the electrical system.
In this case, system is partially liberalized and
the part of the system which is set aside of the
linearization process should be confirmed [10].
This is the case for reflection of steadiness of
internal dynamics of electrical system.
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IS
VS
IS
I S*
Low pass
fliter
Sin wt
Unit vector
generation
Sliding
Surface
eqn. (19)
Sin wt
S
clock
VS
Vc
LOGIC CIRCUIT
PI
Controller
T1
T2
T3
Vcref
T4
Fig.5 Multivariable Controller Design
IV. SIMULATION RESULTS
To check the robustness and efficiency of the
proposed analog SM controller, the complete
shunt APF system is simulated using
MATLAB/SIMULINK. The diode bridge
rectifier having 500-μF capacitor is the nonlinear load used in parallel with a 45-Ω resistor
at its output side. The system parameters used in
the simulation are given in Table 1. Cut-off
frequency of RC low pass filter has been set as
80 Hz. Cut-off frequency and bandwidth of band
pass filter have been set as 50 Hz and 6 Hz
respectively.
Table 1. SYSTEM PARAMETERS
L= 5mH
Vref = 200V
C = 1100µF
𝑉
= 110 𝑉
𝑓 = 50𝐻𝑧
𝑓
= 40𝑘𝐻𝑧
𝜆 = 2000𝑆
𝐾 = 0.5
𝐾 = 10
The THD of the source voltage under ideal
condition is found to be 0.11%. Similarly, the
THD of the load current considering up to 30th
harmonics is calculated as 68.77%. Simulated
load current and source voltage waveforms are
shown in Fig. 6. It is cleared by application of
proposed controller, the source current THD is
reduced to 4.6%. Fig. 7 shows source current and
source voltage waveforms of the proposed
analog SM controller.
Figure 6. load Current and Source Voltage
Fig- 7. Source current, Source voltage and Filter
current with proposed adaptive sliding mode
control
Fig. 8.Dc link capacitor voltage
Finally, this part of paper provides simulation
results to validate the proposed multivariable
control theory. All the results are validated using
MATLAB/SIMULINK 2012a.The various
parameters used in designing of shunt dynamic
power filter are shown in Table II given below:
Table II PARAMETERS OF THE DYNAMIC
POWER FILTER
Parameter
VS
fS
L
C
RO
CO
RS
K1
K2
KP
KI
VC*
fsampling
Value
110 VRMS
50Hz
6mH
1500µF
50Ω
500 µF
5Ω
5000
16650
0.50
10
200
40KHz
The cut-off frequency used in low pass filter is
78 Hz. The proposed multivariable controller
reduces the harmonics by less than 5%. The
total harmonic distortion in source current
after use of this controller is 2.78%.These
results are verified for time period from
0.12seconds and up to 4 cycles. The
simulation results of proposed controller are
verified in MATLAB/SIMULINK 2012a.
These are given below:
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[3]
Fig.9. Load current and Source voltage
[4]
Fig.10.Simulation results of proposed
controller (a) Source Current, (b) Source
voltage (c) filter current
[5]
[6]
Fig.11 Dc link Voltage
The table given below shows the comparison
of the proposed control scheme:
Harmonic (A rms)
THD%
iL
67%
Is(proposed
2.78%
controller)
CONCLUSION
This paper investigates the ATSMC and
PTMC to a single-phase shunt dynamic filter
by implementing the sliding mode control
theory. The comparison shows that PTMC is
better in comparison with ATSMC. Its ability
to reduce harmonics is much better.
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Combined Vector and Direct Power Control of Doubly Fed Induction GeneratorBased Wind Turbines: A Review Paper
Malek Mahammadrizwan M., N. G. Mishra
Department of Electrical Engineering, BVM Vallabh Vidyanagar, Gujrat India
Corresponding Author: rizwanmalek1995@gmail.com
ABSTRACT
In this paper a new innovative combined vector and direct power control (CVDPC) strategy is proposed
for the rotor side converter (RSC) of doubly fed induction generators (DFIGs)-based wind energy
generation system. The direct control of stator active and reactive power based strategy is used by
selection of appropriate voltage vectors on the rotor side. It is observed that the initial rotor flux has no
effect on the changes of the stator active and reactive power. The proposed method only makes use of
the estimated stator flux in order to overcome the difficulties associated with rotor flux estimation. The
proposed DPC method requires only one machine parameter i.e. .the stator resistance which has
negligible impact on the system performance. Simulation results on a 9-MW wind farm consisting of six
1.5-MW DFIG-based wind turbines shows that the effectiveness and robustness of the proposed control
strategy during variations of active and reactive power, rotor speed, machine parameters, and converter
dc link voltage.
Keywords-Direct power control (DPC), doubly fed induction generator (DFIG), direct torque control,
voltage source converter, voltage vector.
will operate only a sub synchronous speed
I.INTRODUCTION
ranges, the GSC might be replaced with a threeDoubly fed induction generator (DFIG) is
phase uncontrolled rectifier In the past many
suitable choice for variable speed wind turbines.
years, a great increase in electrical power
Due to the fact that the DFIG is controlled by the
demand and depletion of natural resources have
rotor circuit and the rotor circuit power
made environmental and energy crises. These
approximately equal to 30% of the stator circuit
have led to an increased need for production of
power, DFIG need small-scale power electronic
energy from renewable sources so that the world
converter when compared with induction
wind energy production has grown significantly
generators or synchronous generators. Therefore
due to cleanness and renewability. Wind power
usage of the DFIG in variable speed wind turbine
generation is estimated to be 10% of the world’s
systems are more efficient [1].
total electricity by the year 2020 and is expected
DFIGs stator windings directly connected to the
to be double or more by the year 2040 [1]. Wind
grid and rotor windings connected to the grid via
turbines (WTs), which play a main role in wind
a bi-directional backto- back converter as shown
energy, are basically divided into fixed and
in Fig. 1. The bi-directional back-to- back
variable-speed technologies.
converter consists of two converters called rotorside converter (RSC) and grid-side converter
II.COMBINED VECTOR AND DIRECT
(GSC). These two converters are connected to a
common DC bus. The rotor side converter is
POWER CONTROL
used to control the active and reactive power of
A.
Vector Control
the DFIG and controls the power factor of the
Vector control is the most popular method used
DFIG. On the other hand grid side converter
in the Doubly Fed Induction Generator-based
keeps the DC bus voltage constant. During the
Wind Turbines. In this control method, the stator
operations between sub synchronous and super
active and reactive powers are controlled
synchronous speed ranges, three phase voltage
through the rotor current Vector Control. The
source converter has to be used as GSC. If DFIG
current vector is decomposed into the
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components of the stator active and reactive
power in synchronous reference frame. This
decouples the active power control from the
reactive power control. The stator active and
reactive power references are determined by the
maximum power point tracking (MPPT) strategy
and the grid requirements, respectively. The
phase angle of the stator flux space vector is
usually used for the controller synchronization.
Although, if the stator flux-oriented frame
(SFOF) is used, the overall performance of VC
will be highly dependent on the accurate
estimation of the stator flux position. This can be
a critical problem under the distorted supply
voltage condition or varying machine
parameters. Therefore, in this paper, the statorvoltage-oriented frame (SVOF) is used for the
controller synchronization. In order to extract
the synchronization signal from the stator
voltage signal, a simple phase locked- loop
(PLL) system is used. The stator active and
reactive powers are as [3].
3
3
PS Re(VS is *) (Vds ids Vqs iqs ) ----------(1)
2
2
3
3
QS Im(VS is *) (Vqs ids Vds iqs ) --------- (2)
2
2
As the SVOF is used for the controller
synchronization, 𝑉𝑞𝑠 disperse and the stator
active and reactive power equations are
simplified to
3
Ps Vds ids ---------- (3)
2
3
Qs Vds ids ---------- (4)
2
According to the stator flux equations in the
synchronous frame [3], in this condition, the
stator currents can be written as
L
ids m idr ---------- (5)
Ls
L
V
iqs m (iqr ds ) ---------- (6)
Ls
s Lm
Substituting (5) and (6) into (3) and (4) yields
3Lm
Ps
Vds idr ---------- (7)
2 Ls
3Lm
V
Vds (iqr ds ) ---------- (8)
2 Ls
s Lm
So, the stator active and reactive powers are
controlled through 𝑖𝑑𝑟 and𝑖𝑞𝑟, respectively. The
block diagram of the RSC-based Vector Control
is shown in Fig. 1.
As shown in Fig. 1 schematic block diagram for
the rotor-side converter control of the DFIG. The
references q-axis rotor current 𝑖 ∗ can be
obtained either from an outer speed control loop
or from a torque imposed on the machine.
These two options may be termed a speedcontrol mode or torque-control mode for the
generator, instead of regulating the active power
directly. For speed-control mode, one outer Pl
controller is to control the speed error signal in
terms of maximum power point tracking
Furthermore, another PI controller is added to
produce the reference signal of the d-axis rotor
current component to control the reactive power
required from the generator. Assuming that all
reactive power to the machine is feed by the
stator, the reference value 𝑖 * may set to zero.
Rotor excitation current control is realized by
controlling rotor voltage. The 𝐼 and 𝐼 error
signals are processed by associated PI
controllers to give 𝑉 and 𝑉 respectively.
Qs
Figure 1. Block diagram of the vector control
strategy of RSC.
B.
Direct Power Control
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In the Direct Power Control method, the stator
active and reactive powers are controlled
directly and the current control loop is
eliminated. The principles of DPC can be
explained by the following stator active and
reactive power equations [7]
Ps =
3Lms
s r sin ----------(9)
2 Ls Lr
3s
L
s s m r cos ----------(10)
2 Ls
Lr
By assuming constant magnitude for the stator
and rotor flux, the derivative of (9) can be
represented approximately as
Qs =
dPs 3Lms
s r cos ----------(11)
dt
2 Ls Lr
Equation (11) shows that the stator active power
dynamics depends on the variation of δ.
Therefore, the fast-active power control can be
achieved by rapidly changing δ. By assuming
constant magnitude for the stator flux and δ the
derivative of (10) can be represented
approximately as
d r
dQs 3Lms
s
cos ---------- (12)
dt
2 Ls Lr
dt
reactive power control can be achieved by
rapidly changing the rotor flux magnitude. The
variation in the rotor flux can be carried out by
applying the appropriate inverter voltage vectors
to the rotor windings to rotate the rotor flux
linkage vector. The rotor voltage equation can be
represented and approximated in a short interval
of ⵠt as
d r
Vr Rr ir Vr r Vr gt ---------dt
(13)
The six inverter voltage vectors can be
appropriately used to control the position and
value of the rotor flux’s by knowing the sector in
which 'r is located. The block diagram of the
direct power-controlled RSC is shown in Fig. 2.
III.Simulation and results
In this section simulation study, using
MATLAB/Simulink, is simulated on a 9-MW
wind farm consisting of six 1.5-MW DFIGbased WTs to compare the performance of the
proposed CVDPC method with both Vector
Control and Direct Power Control strategies.
Fig. 5
Figure 3. Schematic diagram of the proposed simulated system.
Figure 2. Block diagram of the direct power
control strategy of RSC.
Equation (12) shows that the stator reactive
power dynamics depend on the magnitude
variation of the rotor flux. Therefore, the fast-
IV.Conclusion
In this paper, considering the vector control and
direct power control method a new approach to
combined control scheme based on the common
basis of vector control method and direct power
control method has been presented for the rotor
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side convertor of the doubly fed induction
generator. In result, the proposed combined
vector direct power control method gives a
compromise of the advantages of these two
methods.
the variation of the machine parameter. By
implementing CVDPC control method gives
lower power ripple and also high dynamic
response.
Figure 4. Simulation results when the wind speed changes from
15 to 10 m/s.
In the FFT analysis results shows that VCDPC
having less THD than the VC method. Also
provides the decoupling and robustness against
Figure 5. Simulation results when Rr is changed.
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V.REFERENCES
1.
Sevki Demirbas, Sertac Bayhan, “Active
and Reactive Power Control of Doubly Fed
Induction Generator Using Direct Power Control
Technique”, 4th International Conference on
Power Engineering, Energy and Electrical
Drives.
2.
Iwanski G., Koczara W., “Sensorless
Direct Voltage Control Method for Stand-Alone
Slip-Ring
Induction
Generator”,
IEEE
Transactions on Industrial Electronics, 54(2):
1237-1239, 2007.
3.
Demirba,
Bayhan
S.,
“Grid
Synchronization of Doubly Fed Induction
Generator in Wind Power Systems”, III.
International Conference on Power Engineering
Energy and Electrical Drives, POWERENG
2011, Malaga, Spain, 2011.
4.
Jafar Mohammadi, Sadegh Vaez-Zadeh,
Saeed Afsharnia, and Ehsan Daryabeigi, “A
Combined Vector and Direct Power Control for
DFIG-Based
Wind
Turbines”,
IEEE
TRANSACTIONS
ON
SUSTAINABLE
ENERGY, VOL. 5, NO. 3, JULY 2014
5.
G. Abad, J. Lopez, M. A. Rodriguez, L.
Marroyo, and G. Iwanski, “Doubly Fed
Induction Machine Modeling and Control for
Wind Energy Generation Applications”
Hoboken, NJ, USA: Wiley, 2011.
List of Figures:
Figure 1. Block diagram of the vector control
strategy of RSC.
Figure 2. Block diagram of the direct power
control strategy of RSC.
Figure 3. Schematic diagram of the proposed
simulated system.
Figure 4. Simulation results when the wind
speed changes from 15 to 10 m/s.
Figure 5. Simulation results when Rr is
changed.
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Biomass-Diesel based Hybrid Electrical Supply System for Small
Network
Praful Patidar, Chanakya B. Bhatt
Government Engineering College Banswara, India-327001
Nirma University Ahmedabad, India
Corresponding Author: prafulpap35@gmail.com
ABSTRACT
In present time, distributed generation is very common concern to the researchers. Many researchers working
related to micro grid and distributed generation. In rural areas, wastage is available in form of rice husks,
sugarcane bagasse (for biomass), animal dung (for biogas) etc. It can be utilized in form of renewable bio
energy to produce electrical energy. Main idea in this project is to use waste electrical energy and feed rural
areas as well as vital loads. Biomass producer gas can be used in a hybrid system along with diesel to full the
power need of rural area with less carbon emission. It can be standalone or grid connected system. Dual fuel
generator with diesel and biogas/syngas is a favourable solution for emergency power backup and energy crisis.
In this paper, diesel generator set operate in emergency condition and supply the vital load when grid/renewable
source fault occurs and analyse the effect of DG set with stand-alone condition.
This is done by developing numerical models for the simulation of the operating diesel generators as a back-up
energy source in hybrid power systems. The dynamic analysis is completed by the help of Simulation tool.
1.
INTRODUCTION
The increasing demand for energy, the continuous
reduction in existent resources of fossil fuels and
the growing concern regarding environmental
pollution have compelled mankind to explore new
production technologies for electrical energy using
clean renewable sources such as biogas and
biomass energy, solar energy, wind energy, etc.
Among the electric power technologies using
renewable sources are clean, green, silent and
reliable, with low maintenance costs. Along with
these advantages, how-ever, electric power
production systems using as primary sources
exclusively solar and wind energy pose technical
problems due to uncontrollable wind speed
fluctuations and to the day night and summer
winter alternations. As a consequence, in
continuous region, the power supply continuity of
a local grid should be backed-up by other reliable
and non- fluctuate sources of primary energy, such
as diesel generator sets. Such systems, designed for
the decentralized production of electric power
using combined sources of primary energy, are
called hybrid systems. Diesel generator sets also
used for emergency region in conventional sources
energy like nuclear plant. Diesel generator set used
for feed power in isolate region as well as an
emergency region.
The increased interest in using of diesel generator
sets as the main energy source in isolated areas or
as an stand by source in the case of renewablebased power systems can be observed by the great
number of papers and studies carried out in this
area. The research conducted in this domain refers
to aspects such as island operations of diesel
generator sets [3], simulations of diesel/pv/wind
hybrid power systems [4][5],etc.
Figure1: Biomass-Diesel based small Network
2.
Utilization of Biomass as
Engine Fuel
As of 31 January 2014, India had an installed
capacity of about 31.15 GW of non-conventional
renewable technologies-based electricity, about
13.32 % of its total. Total Installed Capacity of Bio
Energy as of 31, January 2014 is 4479.85 MW.
Table 2.1: Overview of biomass energy
Source
Type
Capacity
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Biomass Power and
Gasification
Gridconnected
1285.60
MW
GridBagasse Cogeneration connected
2512.88
MW
Non - Bagase
Cogeneration
Off -grid
517.34 MW
Rural Biomass
Gasifier
Off -grid
17.63 MW
Industrial Biomass
Gasifier
Off -grid
146.40 MW
India produces about 600 million tonnes of
agricultural residues (mainly rice husks, paddy
straw, sugarcane waste, wheat residues and cotton
stalks), of which 300 million tonnes are unutilized
and are disposed of by burning in open fields thus
creating environmental hazards. Diesel engine is
capable of successful running in duel fuel mode of
operation with suitable biomass in gasifier. This
study presents engine performance using rice husk,
rice straw, cotton stalks and bagasse as biomass
fuel in downdraft gasifier in dual fuel mode. Power
Generation application on 100 % producer gas
based system Rs. 15 lacs per 100 KW.
2.1
Introduction
As the engine had to be fuelled with syngas or
biogas, the unit was fed with laboratory blends
contained in specific tanks for compressed gasses.
In Table 2.2 and 2.3 the standard composition and
lower heat content for a syngas and biogas
(anaerobic process) are reported, both derived from
standard biomass and with the percentage in
volume of the different components[6].
CO
CH
2
4
7.0
2.2
H
CO
Others L.H.C
MJ=NM
3
2
41.0 23.0 20.0 9.0 13.0
Experimental work on engine
In biomass gasifier (5 kW, Kirloskar, single
cylinder, four stroke engine with 1500 rpm),
biomass was fed through feed door and stored in
hopper (Fig.2.1). Throat (or hearth) ensures
relatively clean and good quality gas production.
Grate holds charcoal for reduction of partial
combustion products while gas outlet is connected
with engine via venturi scrubber, separator box
cum fine filter and check filter with an air control
valve to facilitate running of engine in dual-fuel
mode [7].
Table 2.4: Characterization of fuels [4]
Calori
c
value,
Biomass
Ash %
C%
H% N%
Cotton stalks
6.68
43.64
5.81
Bagasse
4.27
44.80
6.20 0.20
44.40 0.01 18.11
Rice husk
17.60
38.30
4.80 0.34
35.45 0.03
14.4
Rice straw
10.70
42.30
5.60 0.90
40.50 0.02
11.7
Wood Chips
3.20
48.60
5.56 0.60
41.46 0.03
17.4
0
O % S % MJ/kg
43.87
0
17.4
Table 2.2: Standard composition for a biogas
(Anaerobic) from Biomass
CH
CO
4
62.0
Others
2
35.0
3.0
L.H.C
MJ=NM3
23.0
Table 2.3: Standard composition for a syngas
from biomass
Figure 2.1: Schematic arrangement of
experimental set up [4]
Dust particle of gas also removed by passing
through gas filter. To control of gas valves were
provided in passage of gas and air ow. A single
cylinder naturally aspirated direct injection fourstroke diesel engine coupled with generator was
used for power generation. Dual fuel mode of
operation was carried out by supplying gas to
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combustion chamber of engine through inlet
manifold. Gas control valve is opened gradually to
feed gas into engine. Also, engine governor control
knob is closes to dual fuel position, to decrease
amount of diesel when sound becomes normal.
With rotation of gas valve, optimum adjustment of
gas and diesel is made.
2.3
Result and analysis of energy cost
As producer gas is increased, there is a decrease in
diesel consumption. Hence, higher diesel
substitution in dual fuel mode of operation is
achieved opening producer gas valve fully so that
higher amount of producer gas ow will replace
higher amount of diesel. Sugar cane bagasse fuel
replaced maximum diesel (82 %) at 3 kW load
followed by cotton stalks fuel (80 %). As gas ow is
increased in cotton stalks fuel, diesel substitution
varies from 60.58 - 79.79 %, maximum diesel
substitution is obtained at full opening of gas ow
valve. Wood also replaces a little more diesel (8085%) as both fuels have same characterization
properties. Sugar cane bagasse for producer gas
generation in gasi er showed maximum diesel
substitution (82.1 %) in dual fuel mode. As
compared to cotton stalks and sugar cane bagasse,
diesel displacement in case of rice husk as fuel
is very less (33.36-59.74%), because presence of
small quantities of C (38.3 %) and H (4.5%) and
also very high ash content, which creates hindrance
in producer gas generation. Rice straw gave
minimum diesel replacement (47%), due to
nitrogen present in rice straw that dilutes producer
gas quality and also ash content being very high
creating hindrance in production of producer gas.
Energy costs (Fig. 2) to produce 1 kWh energy (at
3 kW load), cost associated with drying, collection,
storage and transportation of biomass fuels is given
as[4]
Energy cost (Rs/kWh) = (cost of diesel x diesel consumption)
+ (cost of biomass x producer gas consumption)
(2.1)
Looking into energy costs, sugar cane bagasse is
higher than cotton stalks but its
Figure 2.2: Energy cost of fuels [4]
diesel replacement is more than cotton stalks,
because cost of bagasse is higher than cotton stalks.
Diesel engine generator is capable of successful
running in dual fuel mode of operation with
suitable biomass in gasifier because of fuel is
already available. To produce 1 kWh of energy,
630 ml diesel was used at Rs 19.55. Maximum
diesel replacement in dual fuel mode of operation
using cotton stalks in gasifier was 80 %. To
produce 1 kWh of power energy, cost associated
was Rs 4.46. Maximum diesel replacement in dual
fuel mode of operation using sugar cane bagasse in
gasifier was 82%. To produce 1 kWh of power
energy, cost associated was Rs 4.82. Maximum
diesel substitution in case of rice husk was 60% and
to produce 1 kWh of power energy, cost associated
was Rs 9.00. Maximum diesel replacement in case
of rice straw was 47 % while to produce 1 kWh of
power energy, cost associated was Rs 10.97.
Hence, power generation cost while using biomass
is cheaper than conventional power generation
cost.
2.4 Energy cost analysis
Electricity can be generated using gasifiers either
using DG set or using suitably modified natural gas
engines/ producer gas engines. The energy
cost(Rs/kWh) analysis of two types of mode in
generator set are discussed below2.4.1 Dual fuel mode
In this the Gasifier is connected to a diesel
generator and the generator is suitably modified. In
this case up to 70 % diesel replacements are
obtained. To generate 1 unit of electricity .08 -0.1
liter of diesel and 0.9 kg of wood or 1.4 kg of rice
husk would be needed. Depending on the costs of
these (wood chips, rice husk) the fuel cost of
generation can be calculated. Savings obtained
when a gasifier is coupled to a diesel genset is
determined by this calculation.
The cost of 1 liter of diesel is Rs 55.15 and assumed
the cost of 1 kg of wood or rice husk is Rs 5. One
liter of diesel gives 3.5 units of electricity. Thus,
fuel cost of generation for 1 unit of electricity (with
diesel alone) is around Rs 15.75. For generating a
unit of power when the generator set is connected
to the gasifier we need
.08 -0.1 liter of diesel and 0.9 kg of wood or 1.4 kg
of rice husk. If we considered the data (for rice
husk) then using equation 2.1
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Energy cost(Rs/kWh)= (0.1 * 55.15) + (1.4 * 5)
Energy cost(Rs/kWh)= 12.515
the fuel cost of generation for 1 unit of electricity
is INR 12.515.
2.4.2 100% Producer gas mode
Here the Gasifier gets connected to a gas engine
generator set(modified). Biomass produced
gas(producer gas) is directly given as fuel to
generator(no diesel) known as 100% producer gas
engine. To generate 1 unit of electricity it required
1.3 kgs of wood or 1.8 kgs of rice husk. Savings
obtained when a gasifier is coupled to a gas genset
is determined by this calculation, using equation
2.1
Energy cost (Rs/kWh)= (1.3 * 5) + (1.8 * 5) Energy
cost(Rs/kWh) = 15.5
The cost of 1 kg of wood or rice husk is assumed
around Rs 5. So, the cost of generate 1kWh energy
is Rs 15.5. The cost of 1kWh energy of 100%
Producer gas is high because of the cost of rice
husk and wood is assumed equal to Rs 5. If the cost
is less of rice husk and wood the cost of 1 kWh is
also less.
2.5
Sustainability of modified gas engine
Where there is no possibility to connect to the grid
(e.g. the electric energy supply of households,
holiday houses, isolated objectives, equipment in
industrial sites, electric installations for outdoor
entertainment events, military equipment,
telecommunications, etc.), or as emergency
regime, as a reserve electric power source, in the
event of electric power blackouts. In emergency
regime the diesel generator sets usually supply only
vital consumers, like re pumps, elevators, safety
lighting installations, banks, hospitals, government
buildings, offices, mobile towers, supermarkets
and large restaurants, hotels, malls, stadiums,
airports, fuel stations, private houses, and
industrial sites where specific processes do not
allow for blackouts, become uncontrollable or
generate important losses without electric power,
etc. Usually, in parallel with diesel generator sets,
UPS systems are used, with a buffer, able to ensure
for short periods the continuity of power supply for
vital consumers, until the diesel generator sets are
started-up. The minimum combined time necessary
for the detection of a grid voltage drop, the start-up
of internal combustion engine, reaching the
stabilized regime of the generator (frequency and
voltage) and the load connection is typically at
least in few seconds. In the case of power systems
based on renewable energies, given the uctuate
character of unconventional energy sources, diesel
generator sets takes on particular importance, their
role being to ensure the continuity of electric power
for the local grid during periods when the
renewable sources of energy become unavailable
or insufficient. Advantages of this modified gas
engine [9] compare to diesel generator is
Social well being
Economic well being
Environmental well being
Technology well being
3. Diesel Generator Sets
Diesel generator sets convert fuel energy (Diesel
OR Gas) into mechanical energy by means of an
internal combustion engine, and then into electrical
energy by means of an electric machine working as
generator[1]. The main characteristics of a diesel
generator set are : rated power , rated voltage, rated
frequency and number of phases, etc. The diesel
generator sets are usually designed to run at
synchronous speed 3000 rpm or 1500 rpm at a
frequency of 50Hz (for two-pole and four pole) and
3600 rpm and 1800 rpm at a frequency of 60 Hz
(for two-pole and four pole). Speed regulator and
voltage regulator are the two component which
help to give proper operation of diesel generator set
is determined to a great extent. The performance of
these components are vital for the operation and
utilization of diesel generator sets, their purpose
being to precisely maintain the imposed parameters
of electrical power(voltage and frequency). The
relation between speed and frequency(f/N) of an ac
machine is given by this formula𝑃∗𝑁
120
where f = frequency(Hz),
P = number of poles of the generator rotor,
N = synchronous speed (rpm)
and Figure 3.1 shows the general diagram of diesel
generator set.
The equation of electrical power of three-phase
machine are shows the relation between fuel flowrate and power produced by the generator.
𝑓=
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figure 3.2
Figure 3.1: General diagram of diesel generator
set[4]
The equation of three phase electrical power is
given by𝑃 = √3 𝑉 𝐼 cos ɸ
The generator output power is increased or
decreased it is dependent on torque provided by the
machine. In mostly cases the voltage of
synchronous machine is rated or desired so it is
fixed and power factor for resistive load is 1, and if
power factor is assumed that it is equal to 1 then
only current in ampere required to increase, So
stator current is increase while increasing the
torque because stator current is directly
proportional to torque. Input fuel is also directly
related to torque produce by machine it means
increase in amount of fuel, also increase torque and
it is increased the stator current and produced more
power and vice versa. Diesel generator set
combined with Prime mover, excitation system and
synchronous machine.
3.1
Prime mover
The primary movers are internal combustion
engines equipped with mechanical regulators or
governor to keep the imposed speed, integrated in
the injection pump and adjusted to obtain an output
frequency of 50 Hz or 60 Hz for rated load. In
diesel generator sets, there is speed governor
equipped with prime mover. The purpose is
ensuring that the diesel engine can be specified
speed to stable operation. The combination of
diesel engine and governor is used second-order to
modelling and their transfer function also shown in
Figure 3.2: Controlled diagram of Prime Mover
[4]
The speed regulator is basically designed to keep
constant speed of internal combustion engine by
changing the quantity of fuel consumed by the
motor. Actually, frequency is directly proportion to
the generator speed so the direct result of this speed
regulation is a stable frequency of voltage at the
generator terminals. A constant frequency requires
good precision and a short response time from the
speed regulator. The speed regulator starts
regulating when various electric loads are
connected or disconnected at the generator
terminals. There are a lot of speed regulating
systems, starting from simpler spring-based ones
up to complex hydraulic and electronic ones able
to regulate dynamically the fuel admission valve to
keep the speed constant in a given range with
response times at load changes smaller than 1-4
seconds. In figure, 𝜔
(pu) is reference value of
speed equal to 1 and 𝜔(pu)is per unit value of
actual speed of synchronous generator,
𝑃
(pu)is per unit mechanical output power of
diesel engine used to drive generator.Speed of
machine is maintain constant for e ciently using
generator output power and same actuator tries to
adjust the speed of machine. The simulation model
of diesel engine governor is shown as figure 3.3
Figure 3.3: Simulation model of diesel engine
governor
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The Output speed of diesel engine is going through
integral unit conversion for torque. Because diesel
engine is a large time delay system, So the torque
first go through delay unit then multiplied by the
actual speed of machine and such result known as
mechanical power. Here in DG set engine inertia is
combined with the generator inertia. The torque or
mechanical power drives generator and produce
electricity and then it feed to different load.
3.2
Synchronous machine
A synchronous machine is a device for converting
torque into amperes or it converts the mechanical
power into the electrical power. The synchronous
machine block operates in both generator and
motor modes if torque or mechanical power is
positive it works as synchronous generator and if
mechanical power is negative it works in a motor
mode. The numerical models that can be used in
the study of the synchronous generator can be
classified into circuit models and field models,
with the ones most used in electric drive systems
being the circuit models. Before starting the
simulation there is required to initialize the
machine for starting in steady state region.
3.3
excitation system are used because after transient it
will get stable fast so time required very less
compair to other excitation system. The modelling
diagram of AC1A excitation system with its
transfer function is given below in figure 3.4
Excitation system
Excitation system is the important segment to
ensure the voltage accuracy of generation and
improve the stable operation of power system.
Reactive power generation also depend on
excitation system it means if increasing the
excitation being applied to the generator rotor
reactive power will increasing acts as inductive
region and also power factor decreasing that time
while generator terminal voltage and the local grid
voltage increased slightly so result is reactive
power began to ow in the generator stator winding
and real power decreased. The automatic voltage
regulator is to control the voltage at the generator
terminals and keep it constant by limiting as fast as
possible the voltage peaks and over voltages that
occurs due to load variations. The function of
excitation control system mainly in the following
aspects
Maintain generator terminal voltage
constant
Control reactive power allocation of
parallel operation generator
Effectively improve system static stability
Improve system transient stability
In all the cases of diesel generator set AC1A
Figure 3.4: IEEE type AC1A excitation system
model
3.4
Problem Identification
3.4.1 Frequency droop control
The system is in stable condition if frequency
deviation is in range of plus-or-minus 3 %. When
system is synchronize with the other system or grid
with same frequency and voltage level the
frequency is not constant. It always try to maintain
frequency about constant but during sudden load
increasing or decreasing frequency variation is
done. During sudden connection of high load
system frequency will decrease as voltage decrease
and speed of synchronous generator also
decreased. So it will maintain the frequency nearer
to base frequency. The problem like blackout were
occurs only due to this frequency droop so the
control is must require for stable operation of
power system. In figure 4.5 shows how to measure
the frequency of synchronous generator.
3.4.2
Voltage regulation
In most case the generator terminal voltage having
rated or desired value. The range of plus-or-minus
5% are allow to terminal voltage swing but more
than that system collapse. The terminal voltage is
the magnitude of dqo component of stator voltage
V and 𝑉
i.e.
𝑉 = 𝑉 +𝑉
The generator terminal always maintain at 1 per
unit but due to some cases like fault and rapid load
change it will decrease or increase so system is in
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unbalance condition. If generator terminal voltage
is decrease it means the stator current is increase
and vice versa. For stable operation to maintain the
generator terminal voltage equal to 1 pu must
require. In figure 4.5 also shows the measurement
of generator terminal voltage is in Pu or actual
value but in mostly cases it is desired.
Figure 3.5: Block diagram of diesel generator set
3.4.3 Rotor speed droop control
The term fuel, torque, speed and also frequency are
interrelated because speed is directly proportion to
frequency (f∝N). The real power generation also
decreased due to this issue of speed and frequency
droop. For stable or reliable operation speed
maintain by governor or other regulator function
nearer about 1 pu.
3.4.4 Active and reactive power control
The active power and reactive power is directly
proportional to respectively governor(fuel) and
excitation system. Reactive power is increased as
excitation increases and real power is increase as
input fuel increases with the constant power factor.
If reactive power(VAr) increase so power factor is
lagging at that time so it behaves as inductive
region. Excitation is used to control reactive power
in stator terminal of the generator. In figure 4.5
shows the measurement of active and reactive
power generate in stator winding of generator.
3.5
Simulation parameter
Power supply parameters are as follows
Input source rated three phase apparent power :
P = 7:54 MW. Rated voltage: 𝑉 = 25KV.
Rated frequency= 60 HZ. Use a static load of 5MW
to
simulate the total power input
system. The primary and secondary voltages of
transformer are 25 KV-2400 V. Three phase switch
set to close in the beginning, when the three-phase
ground fault happened in 0.1 seconds, the system
detects the failure by the detection system and
disconnects the normal power grid at that time
three-phase switch are to be off. System operating
state is emergency diesel generators running.
Emergency diesel generators synchronous
generator parameters are as follows: Silent pole
rotor type is used in the system, where rated
capacity: P =3:125MVA. Rated voltage: 𝑉 =
2400V. Rated frequency: 60 Hz. Xd = 1:56, Xq =
1:06, Xd’=0.296, Xd"=0.177,Td"=0.05, Td'= 3.7,
stator resistance Rs = 0:816, Inertia coefficient is
1.07 and Pole pairs P=2.
Induction motor parameters are as follows
: rated capacity P = 1:492MV A(0:8889pu), Rated
voltage Ve = 2400V , Rated frequency=60 Hz,
Stator resistance Rs = 0:029ohm, Stator inductance
Ls = 0:0005H, Rotor resistance Rr'=0.022 ohm,
Rotor Inductance Lr'=0.0005 H, Mutual Inductance
Lm = 0:0345H, Moment of inertia 63.87 and pole
pair P=2.
Three static non-dynamic loads are as
follows: Load 1 =5 MW, Load 2 = 0.5 MW and
load 3 = 0.5 MW.
4
Diesel Generator Set
Operating in Standby Mode
5
In the case of important equipment or objectives,
electric power consumers are usually grouped into
vital consumers and non-vital ones. An electric
power security solution for the vital consumers is
to back-up their supply by means of a diesel
generator set. The installation of the diesel
generator set should be done so that during a
blackout resulting from a grid fault, it is possible to
keep connected only the vital consumers. In the
case of wind and/or solar renewable power
systems, a black out could occur in the event of
insufficient solar or wind power. Diesel generator
used mostly for isolated purpose such as in mobile
towers, hospitals, petrol pumps, colleges etc. It is
fact that diesel generator generate 1 kWh energy is
costly than the other alternative sources but
availability and fulfil all demand so diesel
generator is mostly used in isolated load. In case of
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Biogas or biomass gasifier plants, due to weather
atmosphere generation may decreased suddenly so
in such situation a three phase grid is connected in
system which can be represented by a renewable
power system. There are groups of resistive type
consumers have the rated powers 5 MW (non-vital
consumers) and other two each 0.5 MW and a
motor 1.492 MW(vital consumers), and they are
supplied from the grid. When a three-phase to
ground fault occurs at the grid level ,the normally
closed breakers B1 cut the energy supply for the
non-vital consumers(5MW) and the vital load is
supplied by diesel generator set. The three-phase
short- circuit occurs in our case after 1.5 seconds
from the simulation start. At time instant 1.6
second breakers open and diesel generator set are
operated in emergency region. After 6.1 second of
simulation start another single line to ground fault
occurs in to the system and after 6.4 second it will
be automatically cleared also the breaker B2 open
at 6.1 second and auto reclose to 6.4 second Diesel
generator operated in emergency region is shown
in figure 4.1.
Where we can identify the time evolutions of
mechanical power, rotor speed and output power in
per unit. When the short-circuit or fault occurs after
0.1 seconds from the simulation start, the
mechanical power produced by the generator set
increase from a small value because there is no load
connected before 0.1 seconds to the diesel
generator set and stabilizes at the value imposed by
the regulation system, The output voltage period of
time, after which it comes back very quickly at the
rated value. Such a voltage drop can be prevented
by means of a properly sized UPS system and it is
simulated with the help of simulation package in
Matlab.
Figure 4.1: Diesel generator set operated in
standby mode
4.1
Simulation results
Figure 4.2: Mechanical Power of DG during
standby mode
Figure 4.3: Excitation/ field voltage during DG in
standby mode
Figure 4.4: Generator terminal voltage during DG
in standby mode
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Figure 4.8: Generator output current under three
phase short circuit fault
Figure 4.5: Rotor speed of machine during DG in
standby mode
Figure 4.9: Generator output current under single
phase to ground fault
Figure 4.6: Generator output voltage under three
phase short circuit
Figure 4.10: Rotor speed of motor during DG in
standby mode
Figure 4.7: Generator output voltage under single
phase to ground fault
Figure 4.11: Frequency of DG set during DG in
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standby mode
voltage increases about 1.433 pu and it also
stabilize with in few seconds also it shows in figure
4.3. The voltage (pu) at the stator of generator
terminals also demonstrates a significant decrease
for a short time, after which it stabilizes in few
seconds due to the action of the voltage regulation
system. The drop of stator terminal voltage is
shown in figure 5.4. During the transient regime,
due to the sudden coupling of the load, the machine
rotor speed (pu) decreases abruptly, the rotor speed
droop is equal to ((0.97-1)/1 * 100)= -3% but
within few second or short period it stabilized at
the imposed value as a result of the action of the
speed regulating system. The curve of rotor speed
deviation shows in figure 4.5.
Figure 4.12: Active and reactive power during
DG in standby mode
5. Result discussion
The swing equation of machine is also write as
J
also
dω
= T −T
dt
𝜔 𝐽
𝑑𝜔
= 𝑇 −𝑇
𝑑𝑡
So, in stable or steady state operation speed
always be constant to maintain the accelerating
power. In case if load decreasing the torque start
to accelerating and speed and frequency also
increasing when load decreased and if load
increasing the torque start to decelerating and also
speed and frequency also decreasing while load
increased.
In figure 4.1 Three phase fault occurs at
time between 1.5 to 2.0 seconds from the
simulation start. At time instant 1.6 second B1
breaker opened it means renewable source is
disconnected and vital resistive load connected to
synchronous generator. The mechanical power
initially developed by the combustion engine is
very small because the synchronous generator
coupled with the engine is running without load.
After suddenly connecting the resistive load, the
mechanical power developed by the engine
increases rapidly and after few seconds, a new
operation stabilized region is reached. In figure 4.2
shows the curve of mechanical power and it is
cleared that within few seconds it is stabilised.
Excitation voltage initially set at 1 per unit but at
the time of sudden connection of resistive and
motor load transient region occurs and excitation
In figure 4.6 and 4.8 the waveform of line
voltage and line current shows that unbalance
occurs due to the three-phase short circuit fault.
In line voltage at time 1.5 second (During fault)
current ow at low resistance path so voltage
drop is reduced to some extant but in case of
line current at time 1.5 seconds suddenly
increased because load at that time is increased
to some extent. The behaviour of line voltage
and current are shows that how they increased
and decreased during faulty time and then after
opening of circuit breaker at time 1.6 second
DG start to supplying the load and both are
stabilized according their load at that time
because after 1.6 second grid is disconnected.
In figure 4.7 and 4.9 the waveform of line
voltage and line current shows that the effects
of single line to ground fault in the system. In
line voltage and line current at time 6.1 second
fault occurs and at time 6.12 second B2 circuit
breaker opened so it disconnects that load. In
between the unbalance of line voltage and
current are shown in figure they suddenly
increased to at some extant and after opening of
circuit breaker both stabilized with in few
seconds.
In figure 4.10 shows that three phase short
circuit occurs at time 1.5 second and that time
rotor speed decreased and the speed droop is
equal to ((1630-1690)/1690 *100)= -8.9%.
After opening the circuit breaker B1 means grid
is o and DG instantly supply to the vital load
(Motor and resistive) and rotor speed of motor
back in stabilized limit at 1690 rpm. At time 6.1
second another single line to ground fault
occurs and that time also system unbalance and
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at time 6.2 second load being disconnected and
the results of rotor speed of motor shown in
figure 4.10.
In figure 4.11 shows that the frequency curve
for Diesel generator set operated in emergency
condition. At time 1.5 second fault occurs
during this frequency and speed goes down
because both are proportion to each other so
frequency droop during three phase short circuit
fault is equal to((58.25-60)/60*100=-2.1% so it
is inacceptable limit and after that 1.6 second it
is stabilized back to 60 Hz. At time 6.1 second
another single line to ground fault occurs and at
time 6.12 second the grid is disconnected and
system supply by diesel generator set so during
this fault frequency also deviate to some extent
and it will stabilized back to 60 Hz.
In figure 4.12 shows the generated active
and reactive power in output of diesel generated
set. DG start after opening of B1 circuit breaker
when main grid is disconnected till DG no active
power is generate but initially reactive power is
generating it shown in figure about 0.3 MW. At
time 1.6 DG set generate active power nearer about
0.8 MW and it is stabilized after faulty duration.
Another fault come at time 6.1 and at time 6.12
load being disconnected so actual real power
decreased to some extent so it is also shown in
figure 4.12
6. Conclusion and Future scope
Diesel generator set is combination of prime
mover, excitation system and generator so speed
and voltage are required to maintain to operate
system in stable condition.
Diesel generator set increases the reliability of
the system with renewable sources in case of
stand by operation and DG also used as primary
source of supply electricity to vital load and it
is reliable for continuous supply to vital load.
Normally DG rating are small hence they offer
better system performance while connected in
distributed manner.
This is especially suitable in remote areas and
villages where power quality and reliability is a
matter of concern.
Diesel generator are used as backup supply
system but
Dual fuel type like diesel and gas (syngas) DG
engine will impact less on environment and
improves reliability of system.
Use like bagasse, rice husk, wood chips, cotton
stalks etc different type of fuel to replacement
of diesel in DG set so per kWh energy cost also
reduced.
Involving power electronics system to further
improve the performance of the system.
8. References
[1] Robert J. Best, D. John Morrow, David J.
McGowan and Peter A.Crossley,\Synchronous
Islanded Operation of a diesel Generator", IEEE
TRANSACTION OF POWER SYSTEM,
VOL.22,NO.4,NOVEMBER 2007.
[2] S. Krishnamurthy, T.M. Jahns, and R.H.
Lasseter,\The Operation of Diesel Gensets in a
CERTS Microgrid", inConf. Proceed. of 2008
IEEE Power and Energy Society General Meeting
- Conversion and Delivery of Electrical Energy in
the 21st Centruy, pp. 1-8, July 2008.
[3] Tiberiu Tudorache, Cristian Roman,\The
Numerical Modeling of Transient Regimes of
Diesel Generator Sets", Acta Polytechnica
Hungarica.Vol.7,No.2,2010.
[4] Ashish Malik, Lakhwinder Singh and Indraj
Singh,\Utilization of biomass as engine
fuel",Journal of Scientific and Industrial Research.
Vol. 68, October 2009,pp. 887-890.
[5] T. Theubou, R. Wamkeue and I. Kamwa.
“Dynamic Model of Diesel Generator Set for
Hybrid Wind-Diesel Small Grids Applications",
IEEE Canadian Conference on Electrical and
Computer Engineering(CCECE)2012: Montreal,
QC, Canada.
[6] Yao lian-fu, Liu Qian, Li Shi and Zhang
Zhen-yu. “Simulation and Dynamic Pro-cess
Analysis of Nuclear Emergency Diesel
Generators". International Conference on
Informatics,
Cybernetics,
and
Computer
Engineering (ICCE2011) November 1920, 2011,
Melbourne, AISC 112,pp 107-115.
[7] Aparna Pachori, Payal Suhane.\Design and
Modelling of Standalone Hybrid Power System
with Matlab/Simulink",International Journal of
Scienti
c
Re-search
and
Management
Studies(IJSRMS), ISSN:2349-3771.
[8]
Biomass Gasi cation Based Power
Generation by Arashi Hi-Tech Bio- Power Private
Limited.
[9] MNES Annual Report 2002-2003
(Ministry of Non-Conventional Energy Sources,
Govt of India, New Delhi.
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Energy Conservation Options to Transport Solids at Higher
Concentration
Navneet Kumar a,*, Sanjeev Kumar Sharmab, Desh Bandhu Singh a
of Mechanical Engineering, Galgotias College of Engineering and Technology,
Greater Noida, G.B. Nagar, Uttar Pradesh–201308, Email: navneet_mech48@yahoo.com
bDepartment of Mechanical Engineering, Amity University, Noida, Uttar Pradesh
aDepartment
Abstract
Conveying of granular solids in slurry form through pipeline systems is widely applied in industries
due to its several inherent advantages, such as, continuous delivery, flexible routing, ease in
automation and long-distance transport capability, etc. The present need of energy and water
resources conservation, industrial requirement of transporting a large quantity of solids mass and
improved understanding of the flow mechanism of low concentration solids slurry have given an
impetus to the emergence of higher solids concentration slurry transport systems which adds a new
dimension to the slurry transport arena. The present study aims to generate an extensive experimental
dataset from the pilot plant test facility for better understanding the flow pattern in such pipelines.
Pressure drop and solids concentration profiles are the most significant technical indicators need to
be considered in designing the pipeline slurry transportation system. Therefore, a test loop system is
employed to investigate the pressure drop and solids concentration profiles of iron slurry with
different mix proportions which had 105 mm diameter pipe to facilitate investigation of the changes
in the flow characteristics of commercial slurries and to correlate the efflux concentration and flow
velocity with the various design parameters.
KEY WORDS:
iron ore, higher concentration, rheology.
1.
INTRODUCTION
As a viable alternative means of a large-scale
solids transport through pipelines, a slurry
pipeline system is commonly used across the
world for conveying of several materials such
as coal, fly ash, lime stone, zinc tailings, rock
phosphate, gilsonite, copper concentrate, iron
ore etc. In such systems, water is usually being
used as a carrier fluid. Due to huge power
consumption, the method is drawing attention
in recent years. Iron ores through the slurry
pipelines are currently transported from mines
to the processing plants and coming up in large
numbers not only in India but also across the
world. The high concentration slurry pipeline
system has emerged out as a preferred option
of solid materials transportation since it deems
to be an economical and environment friendly.
Further, the present enhanced consciousness
towards the imbalance in the eco-system and
related stringent government policies are also
forcing the industries to adopt environment
friendly transportation systems. Studies
carried out on solids material transport systems
have shown that the slurry conveying at higher
concentration reduces the skewness in solids
concentration profile (Kaushal et al., 2005),
hence, it necessitates a relatively lower
transport velocity as compared to that in low
solids concentration transport systems. This
way, higher concentration slurry conveying
system require less quantity of carrier fluid
with likely reduction of pipeline wear, which
in turn, will eventually increase the life of
pipelines.
In order to optimize the performance of slurry
pipeline, an experimental database is essential
to design an optimal slurry pipeline system. It
is, thus, desirable to have the concentration of
commercial slurries high, to an extent possible,
so as to make the system economical.
Published data (Thomas, 1978; Soo, 1987;
Slatter and Wasp, 2002) have shown that fine
particles slurries at solids concentration above
50% by weight behave like pseudohomogeneous suspensions. Thus, the pipeline
can be operated at significantly lower
velocities since the critical deposition velocity
for such slurries are observed to be very low.
Increased solids concentration beyond 50% by
weight makes it possible to convey the slurry
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through pipeline in laminar regime since the
slurry exhibits non-settling behaviour.
Bunn & Chambers (1993) found that
such
slurries
display
non-Newtonian
characteristics at higher solids concentration.
Gopaliya and Kaushal (2016) performed the
sand-water slurry flows through horizontal
pipeline and highlighted the effect of grain
sizes on various slurry flow parameters.
Recently, Kumar et al. (2016) performed
numerical simulation of horizontal slurry flow
(water-glass beads) of coarse particles
suspensions in a Newtonian carrier fluid.
Glass-beads-water slurry having 440μm mean
diameter particles is analyzed through 54.9
mm diameter pipe at efflux concentrations up
to 50% flowing with different slurry velocities
up to 5 m/s. A significant number of literatures
on low concentration slurry transport systems
have reasonably explained the transport flow
characteristics of solids but the phenomenon is
not yet fully understood for conveying of
higher concentration slurry owing to complex
interactions among the constituent phases.
Therefore, the present study delves deep into
the transport mechanism of higher
concentration
slurries
by
conducting
experiment investigations. In order to address
these concerns, experimental analysis of 12µm
iron-ore slurry flows through 105 mm
horizontal pipe having efflux concentration
and mixture velocity ranges of 2.63 to 31% (by
volume) and 1.35 m/s to 5.11 m/s respectively
have been performed during present study.
2.
MEASURED MATERIAL AND
BENCH SCALE PROPERTIES
The physical properties of iron ore are given in
Table 1. The measured specific gravity and
median particle size d50 of iron ore are 4.35 and
12µm respectively.
Table 1
Physical properties of iron ore
(a)
Specific gravity of iron ore = 4.35
(b)
Settling characteristics of the iron ore
suspension (Initial concentration Cw = 30% by
weight)
Time
0 0. 1 5 2 50 80 14
(minu
5
5
40
tes)
Settle 3 32 3 42 6 79 83 83
d
0. .2 5. .3 5. .5 .0 .0
conce 0 0 0 0 0 0 9 9
ntrati
on (%
by
weigh
t)
Final static settled concentration (Cw)ss =
83.09% by weight or (Cv)ss = 53.04% by
volume.
2.1. RHEOLOGICAL
SLURRY
TESTING
OF
Slurry rheology is the most important key
parameter in the design of slurry pipeline
transportation system for the flow of
Newtonian and non-Newtonian fluids. The
rheological property so obtained was used as
input parameter to determine the pressure drop
for the estimation of pumping power. The
rheological experiments were conducted using
RheolabQC (Anton Paar GmbH, Austria). In
this study a RheolabQC with measuring cup
CC27 and a sensor system ST22-4V-40 having
4-bladed vane geometry was used. The
diameter and length of the vane rotor was 22
mm and 40 mm respectively.
2.2. EFFECT
CONCENTRATION
RHEOLOGY
OF
ON
SOLID
SLURRY
The rheological data in terms of shear stress (τ)
and shear rate (γ), in slurry concentration range
for iron ore of 18.69–56.57% (by vol.) has been
collected. It is seen that the variation of the shear
stress with shear rate at all follow straight line
behaviour. The data
of
rheological
characteristics analyzed by adopting the
Bingham-plastic model. The rheological
characteristics of slurries are strongly affected
by the solid concentration in Fig. 1(a-c). With
the solid concentration increases, it would
become progressively more strongly nonNewtonian fluids, signifying a remarkable
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shear-thinning characteristic over the entire
shear rate range. The variation of apparent
viscosity versus shear rate with concentration
is presented in Fig. 1(d-f). It is observed that
the apparent viscosity increased with the
increase of solid concentrations and decreased
with the increase of shear rate.
(a)
(b)
(c)
(d)
(e)
(f)
Fig.1 Rheological Characteristics of iron ore
slurry at different solid concentration
3.
EXPERIMENTAL FACILITY
Pilot plant test loops are suitable for studying
the effect of flow rates, mixture velocity and
concentration on flow behaviour, pressure
drops and solid concentration profiles is laid
horizontally in the Fluid Mechanics
Laboratory at I.I.T. Delhi. Each test rig
consists of 50 and 105 mm diameter pipes
approximately 60 m long (see Fig. 2). The
mixing tank, measuring tank, slurry pumps,
two pipe loops of different diameters and by
pass line are the major components of pilot
plant test loop. The slurry is prepared in a
hopper shaped mixing tank. It is made from 4
mm thick mild steel sheets with height of 2 m.
On other hand, this tank is also provided with
a mixer arrangement by an electric motor
mixes the water and the solid particles
mechanically. The slurry is pumped from this
tank into the 105 mm diameter pipe loop by a
centrifugal slurry pump (WILFLEY Model,
Ni-hard coupled with 50 HP motor) and flow
in the 50 mm diameter pipe loop obtained by
means of a rubber lined slurry pump (M/s.
International Combustion Ltd.). Both the
pumps are having sufficient capacity to cover
the entire range of head and discharge needed
at all concentrations in both different diameter
pipe loops. The flow rate of the slurry in the
two pipe loops is maintained over a wide range
by AUDCO valves (plug types) provided near
the delivery of the pump in each loop. A
diverter is also provided at the main exit of the
pipe loop which facilitates the diversion of the
flow to the concerned measuring tank. The
shape of measuring tank is hopper type with
height of 1.5 m and total volume capacity (1.25
m3). The magnetic flow meter provided in the
vertical section of the pipeline. To ensure the
accurate flow rate of slurry, further, a
calibrated electro-magnetic flow meter was
also installed in the horizontal section of the
pipeline for regular monitoring of flow. The
slurry volumetric flow rates and velocities
were measured using electro-magnetic flow
meters. For the visualization of slurry flow to
estimate the deposition velocity, a transparent
(perspex pipes small length) observation
chambers in straight reach of the pipelines
were installed in both pipe loops. It gives the
idea about deposition velocity to avoid the
chocking of the slurry pipeline system.
The minimum slurry flow velocity is usually
kept more than the deposition velocity. Many
pressure taps along with separation chambers
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have been installed at different positions in the
straight reach and pipe bends of pilot plant
loop. Separation chambers were provided at
each pressure tab so that slurry does not enter
in manometric tubes or interface separation of
the slurry and the manometric fluid (water) as
intermediate fluid.
Fig.2 Schematic diagram of pilot plant test
loop
The pressure drop between any two pressure
taps was measured in either of the pipe loops
by using differential pressure transducers (with
capacity of 100 KPa) and flow rate was
controlled in each pipe of pipe loops by plug
valves fitted in the individual loops. To ensure
the fully developed flow, the pressure taps are
provided more than 50D where D is the pipe
inner diameter, the gets flow fully developed.
To determine the local solid concentration
distribution through the pipe cross-section, a
sampling tube for drawing out samples is
provided in each loop. Concentration
distribution in the straight pipe and along the
bend tangent length has been measured using a
sampling tube having a 4 mm x 6 mm
rectangular slot 2 mm above the end to collect
representative samples in the pipe line.
Samples are collected from different heights
from bottom of the pipe in the vertical plane of
the cross-section to a sieve analysis to measure
the concentration profile at each elevation
under near isokinetic conditions. During the
collection of samples, it is ensured that the
flow of the slurry through the sampling tube
outlet is nonstop and uniform. At the end of the
pipe loop a sampling point is also provided in
the vertical portions to collect an average
efflux sample. The accuracy of the sampling
tube is checked by integrating the measured
concentration profile to obtain overall
concentration and comparing it with the
measured efflux concentration. During the
collection of concentration samples at various
locations, it was ensured that the flow of the
slurry through the sampling tube outlet is
continuous and uniform. The specific gravity
of the slurry flowing through pipeline is
determined by collecting samples through a
sample point provided in the vertical section.
4.
RESULT AND DISCUSSION
In the present work, an effort has been made to
generate the data for pressure drop and
concentration distribution in 105 mm internal
diameter of pipelines for the flow of iron ore
commercial slurries at higher concentrations.
During the pilot plant loop test facilities the
settling of the slurry was not observed even at
the minimum value of the flow velocity at any
efflux concentration of slurry tested.
4.1. PRESSURE DROP
Pressure drop for iron ore slurry of 12µm
particles are presented in Fig. 3 at seven
different efflux concentrations namely 0, 4.91,
7.83, 11.8, 16.6, 23.48 and 31% by volume. It
is observed that the pressure drop at any given
flow velocity increases with increase in
concentration. This trend is seen for all
concentrations at all velocities. The rate of
increase in pressure drop with concentration is
comparatively small at low velocities but it
increases quickly at higher velocities, pressure
drop is more at higher velocities, due to greater
surface area causing extra frictional losses in
suspension.
4.2. CONCENTRATION
AND DISTRIBUTION
PROFILES
To calculate the energy dissipation in the pipe,
knowledge of the concentration and size
distribution of solids is also essential.
Evidently the local chord concentration can
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0.5
V=4 m/s
V=5.11 m/s
0.3
y'
0.1
-0.1
-0.3
-0.5
0
0.5
0.5
y'
0.1
-0.3
-0.5
0
0.5
0.5
1 1.5 2
C(y')/C vf
2.5
3
V=1.35 m/s
V=2.15 m/s
V=4.92 m/s
0.3
y'
0.1
-0.1
-0.3
-0.5
0
0.5
1 1.5 2
C(y')/Cvf
2.5
3
(a) Cvf = 2.63%
(b) Cvf = 4.91%
(c) Cvf = 7.83%
0.5
V=1.72 m/s
V=2.55 m/s
V=3.3 m/s
V=4.9 m/s
0.3
y'
0.1
-0.1
-0.3
-0.5
0
0.5
0.5
1 1.5 2
C(y')/Cvf
2.5
3
V=1.41 m/s
V=1.87 m/s
V=2.63 m/s
V=3.11 m/s
0.3
0.1
-0.1
-0.3
-0.5
0
0.5
Cvf = 4.91%
Cvf = 7.83%
0.5
Cvf = 11.8%
0.3
Cvf = 16.6%
1 1.5 2
C(y')/C vf
2.5
3
V=1.68 m/s
V=2.21 m/s
V=2.85 m/s
0.1
y'
Pressure Drop (kPa/m)
3
-0.1
Water data
2
2.5
V=1.61 m/s
V=2.62 m/s
V=3.65 m/s
V=5.07 m/s
0.3
3
2.5
1 1.5 2
C(y')/Cvf
y'
show a clearer picture of the distribution of
solid particles and their movement in the
vertical axis of the pipe cross-section. The
distribution of solids across the cross-section
depends on various factors, such as flow
velocity, the vertical depth of the pipe, the
particle size, its density and solids
concentration etc. Solid concentration
distribution was measured using a traversing
mechanism and isokinetic sampling probe at
six levels in the vertical plane. Measured
vertical Solid concentration distributions are
shown in Fig. 4 (a-f) at different flow
velocities. Fig. 4 (a-f) shows concentration
distributions in the vertical plane for iron ore
slurry of 12 µm, by C(y')/Cvf where C(y') is the
volumetric concentration at y' = y/D, y being
distance from the pipe centre and D the pipe
diameter and Cvf, is used average efflux
concentration in each experiment. It is
observed that the degree of asymmetry in the
solids concentration distributions for same
concentration of slurry increases with
decreasing velocity. From these figures, the
skewness keeps reducing with increase in
concentration. It is also observed that for a
given velocity, increasing concentration
reduces the asymmetry in the vertical solid
concentration distributions because of
enhanced interference effect between solid
particles. The effect of this interference is so
strong that the asymmetry even at lower
velocities is very much reduced at higher
concentrations.
Cvf = 23.48%
-0.1
Cvf = 31%
1.5
-0.3
-0.5
0
1
0.5
0.5
(d) Cvf = 11.8%
(f) Cvf = 23.48%
0
0
1
2
3
Vm (m/s)
4
5
1 1.5 2
C(y')/C vf
2.5
3
(e) Cvf = 16.6%
6
Fig.3 Measured pressure drop variation with
flow velocity at different solids concentration
Fig. 4 Measured solid concentration
distributions in a horizontal pipe
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5. CONCLUSIONS
Bench scale, rheological properties and pilot
plant loop testing were determined
experimentally. Pilot plant loop test involving
conveying of iron ore slurries through straight
horizontal pipeline at various solid
concentrations revealed that the pressure drop
increases with the increase in slurry
concentration for a given flow velocity. It is
also found that for all efflux concentrations,
the extent of asymmetry in the concentration
profile increases with decrease in the flow
velocity. This is expected as a reduction in
flow velocity there will be a decrease in
turbulent energy which is responsible for
keeping the solids in suspension. Asymmetry
in the concentration profile at any given flow
velocity tends to decrease with increasing
slurry concentration because of enhanced
interference effect between particle- particle.
The cause of this interference is so strong that
the asymmetry even at lower velocities is very
much reduced at higher concentrations.
2.
3.
4.
5.
6.
7.
REFERENCES
1. Bunn, T.F., Chambers, A.J., (1993).
Experiences with dense phase hydraulic
conveying of vales point fly ash. Powder
Handling and Processing, 5, 35-43.
Gopaliya, M. K., Kaushal, D. R., 2016.
Modeling of sand-water slurry flow
through horizontal pipe using CFD.
Journal
of
Hydrology
and
Hydromechanics. 64 (3), 261–272.
Kaushal, D.R., Sato K., Toyota T.,
Funatsu K., Tomita Y., 2005. Effect of
particle size distribution on pressure drop
and concentration profile in pipeline flow
of
highly
concentrated
slurry.
International Journal of Multiphase Flow,
31, 809-823.
Kumar, N., Gopaliya, M. K., Kaushal, D.
R., 2016. Modeling for slurry pipeline
flow having coarse particles. Multiphase
Science and Technology, 28 (1): 1-33.
Slatter, P. T., Wasp, E. J., 2002. The
Bingham plastic rheological model: friend
or foe? Proc. Hydrotransport 15, BHR
Group, Cranfield, Bedford, England, pp.
315-343.
Soo, S. L., 1987. Pipe flow of dense
suspensions. Journal of Pipelines, Vol. 6,
pp. 193-203.
Thomas, A. D., 1978. Coarse particles in a
heavy medium-turbulent pressure drop
reduction and deposition under laminar
flow. Proc. Hydrotransport 5, BHRA,
Hannover, Germany, paper D5.
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Analysis of Process Characteristics for a Batch Production Unit and
Controlling the Variation for Effective Performances
Navneet Kumar a,*, Sanjeev Kumar Sharmab, Krishna Mohan Agrawalb
aDepartment of Mechanical Engineering, Galgotias College of Engineering and Technology, Greater
Noida, G.B. Nagar, Uttar Pradesh–201308, Email: navneet_mech48@yahoo.com
bDepartment of Mechanical Engineering, Amity University, Noida, Uttar Pradesh
Abstract
Even after such advancement and evolution in the field of manufacturing unit, it is still lacking in delivery
quality product as per customer requirement and this can be due to rigidity to change, uncertainties in the
system and fluctuation in the desired value. Process is a pre-defined work in which the raw material is
converting into a finished goods. Due to variation in the process input parameters, there is an effect on
the output product which reduce its effectiveness and reliability. Therefore, it is very important to reduce
or control the variation in the process characteristic to sustain the product in a such demanded market.
The research is done to analyze each process of a capacitor manufacturing unit using Process flow chart,
Failure Mode Effect Analysis and Process control plan to identify the various processes that are at risk,
its effect on the output product and developing a control plan for an effective performance and
maintaining the quality of work.
Keywords: Process Flow Chart, Failure Mode Effect Analysis, Process Control Plan, Risk Priority
Number.
Introduction
in the market. The aim of the research is to
With wide range of applications, capacitor is
analyze each process characteristics of capacitor
coupled in many electronic equipment from
manufacturing which is to identify the risk,
small to large also called as power capacitor. The
effect on the output product and developing a
main aim of capacitor is to have standard
control plan for reducing and controlling the
capacitance value with which it can bear the high
effect of variation of process parameters on the
current and voltage frequency in the any
final product. Hence, Control Plan is a method
electrical equipment. Different processes play
for documenting the functional elements of
significant contribution in the production of
quality control that are to be implemented in
capacitors like winding, baking, spraying,
order to assure that quality standards are met for
welding and each process have individual
a particular product or service. It can be utilized
importance for acquiring a quality capacitor.
for maintaining the working conditions and also
Most of the manufacturers are implementing
a scope for more improvements in the near
various technologies to get the best quality
future. Furthermore, a Quality Control Plan is a
capacitor which leads to a high investment.
critically important document for any
Various regulations have to be considered while
manufacturing unit. It is a description of the
manufacturing capacitor as a safety for
activities, tools and procedures, needed
environment, spraying and coating is a valueto control process that delivers a service or
added process which use zinc, zinc-tin and
product. Finally, the overall objective is to
powder for which the remaining waste goes to
minimize and control variation that will be
environment. Manufacturing a good capacitor is
beneficial for the enhancement of the product.
not that much important rather manufacturing it
Literature review
with
healthy
environment.
Nowadays,
Detailed study has been done on FMEA with
continuous improvement tool is getting popular
RPN to identify the risk or variation in the
in many manufacturing units to analyze their
process and its effect on the product but
working conditions and to sustain their product
integrated control plan study is rarely found for
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a process industry. In 1990, B. G. Dale and P.
Shaw did a questionnaire survey on the use of
failure mode and effects analysis (FMEA) in the
United Kingdom motor industry from 78
organization in which they concluded that in
many organization are seeking to make more use
of this technique to facilitate their process of
quality improvement. In 1991, Bejamin C.Wei
present a unified approach in performing
FMECA applicable to a large plant design and
has establish the steps necessary to perform a
failure mode, effects and criticality analysis on
any item at any level. Later in 1992 warren
Gilchrist proposed that FMEA is a major tool for
quality improvement, it seeks to prevent faults in
product and processes at the design stage and it
provides a structured approach to analysis. Later
in 1995, Sheng-Hsien(Gray) Teng proposed that
Failure mode effect analysis as an integrated
approach for product design and process control.
The aim of performing FMEA is to develop an
effective quality control system, to improve the
current production processes, and to ensure high
quality and reliability of the products. The
integration of FMEA process to product design
and process control is absolutely critical to the
success of FMEA. In 1998, S. A. Abbasi and
Faisal I. Khan did a review on the risk analysis
in a chemical process industry in which they
address FMEA as technique for identify the
failures and its effect. In 2006, Daniel Le Saux
implemented the process control plans and
FMEA in a semiconductor manufacturing
environment in which they concluded that
various significant improvement can be
achieved in a controlled, proactive manner when
process control plans and a dynamic FMEA are
developed and maintained. Later in the same
year J.Maiti did research on risk and proposed
an effective use of resource can be achieved by
using risk based maintenance decision to guide
where and when to perform maintenance.
According to Automotive Industry Action
Group(AIAG), Process control are an
automotive and aerospace quality tool and
considered an output of the Advance Product
Quality Planning (APQP) process. In 2009,
Benjamin Kemper did the modelling of process
flow using various symbols and diagram and
address that process diagram, originally used as
a design tool in information technology,
nowdays visualize process flow document
process performance which display relevant
process with process characteristics. In 2010,
S.Q.(shane) Xie et al. explains that the process
flow chart/diagram is able to effectively
represent the type of process knowledge that
carriers flow information and generates a visual
view of each process of the system.
Subsequently in 2104, T.sahoo et al did the
implementation of FMEA approach which
shows its contribution in reducing the
maintenance cost, indeed it defines the
requirements of dependability in precise
manner. It also identifies critical functions for
the system and several maintenance policies for
the system and its components. More recent in
2015, N Rachieru et all did the risk analysis of a
CNC lathe using FMEA to deal with the risk
factors and identify the most serious failure
modes for corrective actions. Most of the
research is done using FMEA with RPN for
process variation/risk assessment but, I have
applied an integrated framework as shown in fig
1 as PFD, PFMEA and PCP to each components
of a capacitor manufacturing unit to determine
the critical process and its risk in the near future
and has developed a control plan.
Process
Process Flow Chart
Process
Process Control Plan
Corrective Work
Fig .1 Integrated Framework
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Case study
This capacitor manufacturing unit is renowned
for delivering the effective and safest capacitor
in such high competition market to its customer.
To continue their quality and substantiality in the
market, they are approaching continuous
improvement with Advance Product Quality
Planning process in their manufacturing unit of
capacitor. So, an in-depth analysis on process
and product characteristics is performed to
identify the failure cause and its effect on the
output product and finally control factors are
obtained.
Methodology
Process flow chart
A process flow chat (PFC) is defined as a formal
graphic representation of a process sequence,
work or manufacturing process, organization
structure (Lakin et al., 1996). It represents
symbols which are used to represent each
operation, data, flow direction, equipment etc.
(Aguilar -saven 2003). The flow chart consists
of product and process characteristics with
standard specification of each process
parameters. It is used as the initial chart for
analyzing the variation in the product and
process quality. Various symbols used in process
flow chart are shown in the table no. 1 and
process flow chart/diagram of current research
work is also shown in table no.2
Table no. 1
Symb
ols
Descr
iption
2
Oper
ation
Inspe
ction
Transp
ortation
Opera
tion
&Insp
ection
De
lay
Stor
age
Deci
sion
Mak
ing
Process Failure Mode Effect Analysis
Failure Mode Effect Analysis (FMEA) is a
systematic method of seeking out the potential
causes of failure before they become a reality.
Hence, it becomes mandatory to be applied
during the development stage of product service
(warren Gilchrist 1992). The first step in FMEA
is to identify all the possible failure modes of the
product and system, then the potential effect of
the failure modes on the product and process
with the cause of the failure mode. Critical
analysis is performed on the identified failure
modes by taking the following risk factors
1Occurrence (Probability of failure)
2Severity (Severity of the failure)
3Detection (Probability of the nondetecting the failure)
The ranking of failure mode for critical actions
is determined in terms of risk priority number
(RPN) (N Rachieru et al.,2015), where RPN is
the product of O*S*D. After the evaluation of
RPN of each process, ranking is done in
decreasing order to get the maximum RPN
process. FMEA uses a scale from 1 to 10 for
evaluating the risk factors as shown in table no.3
and table no.4 shown the FMEA of capacitor
manufacturing system.
Process Control Plan
A process control plan (PCP) is a summary of
the methods and systems used to control parts
and processes according to customer
requirements. It addresses product and process
characteristics and requirements for control also
aims at minimizing the variations. The entire
control strategy for a system, subsystem,
component or a part is summarized (Daniel Le
Saux 2006). It is the final stage in which analysis
of PFD and PFMEA data is done for controlling
the variation of each process of a system or
subsystem and also determines the methods and
measurements for controlling the variation when
and by whom. Following are the main factors in
process control plan/chart and for the capacitor
production unit, it is shown in table no.5
1- Process and product attributes: important
characteristics or variables
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2- Machine, Tool or Device: equipment used
to perform the task
3- Control
Characteristics:
process
parameters being controlled
4- Method: procedure/medium required to
control the current process parameters
5- Frequency: how often the process control
take place
6- Reaction plan: activity that will take place
if the process control fails
Classification: quality, safety and regulations as
per norms
Table no.2
Operation
sequences
Operation
description
Incoming
source of
variation
Significant
product
characteristics
(output)
Significant
process
characteristics
(input)
comments
or notes
Winding
Winding of the
inner and outer
film to wrap on
mandrill
Maintenance
and tool
Film capacitor
with length and
width, wave cut
and diameter
Main film turn,
pressure roller
tension, stagger,
burn off foil
No quick
action on
breakdown
Pressing
To remove holes
and gap between
films of
capacitor
Capacitors
masked in
different rolls
Spraying of zinc
and zinc-tin on
roll through gun
Cold pressing
Pressed capacitor
to make strong
bond
Maintenance,
winding,
equipment
Masking,
winding,
machine
parameters
Operator
variation,
masking and
spraying
Spraying
Capacitor rolled in
bulk for spray
operation
Material deposited
on side edge of
each capacitor
Temperature,
pressure,
counting, time,
jig, pads
Roll diameter,
ohms design and
tape
Pressure,
deposition area,
wire feeding
speed, voltage
Hand process
either manually or
automatic
More
number of
bins for
flow
Poor
material
handling
Less
resource and
recycle the
waste
Variation in
time due to
odd/bad
masking
Waiting due
to less
material
High
changeover
time
Excessive
and poor
material
handling
Waiting due
to material
variation
2
Masking
Spraying
Demasking
Short
clearance,
welding
To demask the
masked
capacitors in
units
Smoothen the
side edges of
capacitor
To remove
errors and
defects
Rectification of
gap and welding
of lead on side
Pre-heating,
wax, paint
coating
Heating and
protection from
the atmosphere
Operator
variation and
material
Marking
Labelling of
specification
and lot number
Heating of
capacitor
Naked eye
inspection
To disjoint units
from rod
Operator and
maintenance
Deburring
Baking
Post
Curring
Visual
Inspection
Disjoint
Environment
Spraying and
operator
variation
None
Operator
None
Unrolled capacitor
for the further
operations
Removal of
excessive spray
material
Heated capacitor to
remove errors and
defects
lead terminal on
side edge of
capacitor and
tapping on rod
Coated capacitor to
withstand the
ambient conditions
Indication of value
for specific
function
Defect and error
proof
Acceptance or
rejection
Disjointed units
Time and speed
(RPM)
Temperature and
time
A.C/D.C voltage,
length, pressure,
weld area and
pitch
Time,
temperature,
vacuum, coat
thickness
Marking code,
machine speed
and lot number
Time and
temperature
Undip, joint,
bubble, welding
Machine speed
Delay due to
break down
None
Less no. of
observation
None
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Testing
Effectiveness of
each unit
Powder
coating, VI
Reliable capacitor
to function
Lead cut
form
Cutting in
length and shape
Visual
inspection
Final
inspection
Packaging
Final quality
check
Packing of units
in box to
customers
Material
capacitor in
different cut form
on demand
Acceptance high
rejection high
Capacitors in box
or packet to
delivery
None
Table No.3
Linguist
ic terms
Scale/Ra
nk
Very
low
1/2
Low
3/4
Relatively
few
Moderat
e
High
5/6
Occasiona
l
Repeated
Very
high
9/10
7/8
Occurren
ce of
Failures
Unlikely
Unavoida
ble
Severity
Detecti
on
Minimal
interferen
ce
Significa
nt
degradati
on
Minor
damage
Equipme
nt
damage
Destructi
ve failure
Easily
Moderat
e
Hidden
Difficult
Very
difficult
Conclusion
Failures are part of system in any manufacturing
unit which affect the sustainability of their
product, which cannot be fully eliminated from
the system but can be minimized or controlled so
that it has less effect on product characteristics.
The present work is an analysis of process
characteristics of capacitor manufacturing
industry for determining the failures occurring in
the system and its effect on the output product
using PFC, FMEA and PCP. The FMEA chart
with RPN identifies that spraying is the most risk
bearing process followed by winding and
welding which caters for careful investigation
for these components in all the areas. A quality
process plan is also developed to reduce or
control the process variation. These results will
be help to increase the effectiveness and quality
of the output capacitor with balanced working
environment.
H.V, I.R testing,
S.C VDC/AC,
CAP.value@1khz
Lead cutting
length, pitch,
burr/scratch
Defects, AQL,
RE, Dimensions
Packing type,
customer name,
piece/polybag
Rework
None
Poor
handling
None
References
1. Dale, B. G., & Shaw, P. (1990). Failure mode and
effects analysis in the UK motor industry: A state‐
of‐the‐art
study. Quality
and
Reliability
Engineering International, 6(3), 179-188.
2. Kemper, B., de Mast, J., & Mandjes, M. (2010).
Modeling process flow using diagrams. Quality
and Reliability Engineering International, 26(4),
341-349.
3. Warren Gilchrist, (1993),"Modelling Failure
Modes and Effects Analysis", International
Journal of Quality & Reliability Management,
Vol. 10 Iss: 5 pp. 16-23.
4. Teng, S. H., & Ho, S. Y. (1996). Failure mode and
effects analysis: an integrated approach for
product design and process control. International
journal
of
quality
&
reliability
management, 13(5), 8-26.
5. Khan, F. I., & Abbasi, S. A. (1998). Techniques
and methodologies for risk analysis in chemical
process industries. Journal of loss Prevention in
the Process Industries, 11(4), 261-277.
6. Le Saux, D. (2006). The Effective Use of Process
Control Plans and Process Failure Mode Effects
Analysis
in
a
GaAs
Semiconductor
Manufacturing Environment. In 2006 GaAs
Mantech Conference ACRONYMS AOI:
Automated Optical Inspection HVI: Human
Visual Inspection.
7. Arunraj, N. S., & Maiti, J. (2007). Risk-based
maintenance—Techniques
and
applications. Journal
of
hazardous
materials, 142(3), 653-661.
8. AIAG, Advanced Product Quality Planning and
Control Plan, (2001).
9. Wei, B. C. (1991, January). A unified approach to
failure mode, effects and criticality analysis
(FMECA). In Reliability and Maintainability
ISBN-978-81-932091-2-7
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December 22-23,
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Symposium, 1991. Proceedings., Annual (pp.
260-271). IEEE.
10. Chen, W. L., Xie, S. S., Zeng, F. F., & Li, B. M.
(2011). A new process knowledge representation
approach using parameter flow chart. Computers
in industry, 62(1), 9-22.
11. Sahoo, T., Sarkar, P. K., & Sarkar, A. K. (2014).
Maintenance optimization for critical equipments
in process industries based on FMECA
Method. Int J Eng Innov Technol, 3(10).
12. Rachieru, N., Belu, N., & Anghel, D. C. (2015).
An improved method for risk evaluation in failure
modes and effects analysis of CNC lathe. In IOP
Conference Series: Materials Science and
Engineering (Vol. 95, No. 1, p. 012139). IOP
Publishing.
13. Aguilar-Saven, R. S. (2004). Business process
modelling: Review and framework. International
Journal of production economics, 90(2), 129149.
14. Lakin, Richard, Nick Capon, and Neil Botten.
"BPR enabling software for the financial services
industry." Management services 40.3 (1996): 1820.
Table no.4
Operation
sequences
Process function
Product characteristics
Potential
failure
mode
Potential
effect of
failure
Potential
cause of
failure
O
S
D
RPN
Ranking
Winding
Winding of the
inner and outer
film to wrap on
mandrill
Film capacitor with length
and width, wave cut and
diameter
Oversize
Capacitance
decreases
3
9
2
54
2
Undersize
No
functioning
Positive
value of
stagger
Negative
stagger
2
8
2
32
5
To remove holes
and gap between
films of capacitor
Capacitors
masked in
different rolls
Pressed capacitor to make
strong bond
None
None
0
0
0
0
Machine
design and
operator
effort
Insufficient
air pressure
and current
2
2
28
6
Material deposited on side
edge of each capacitor
3
7
3
63
1
To demask the
masked capacitors
in units
Unrolled capacitor for the
further operations
Excessive
work
Excessive
material in
gap leads
wastage
100%
Deposition
is not
achieved
More effort
and loss of
deposited
material
7
Spraying of zinc
and zinc-tin on
roll through gun
Gap in
between
ohm
masking
Inaccurate
Deposition
5
2
2
20
8
Deburring
Smoothen the side
edges of capacitor
Removal of excessive
spray material
None
None
None
0
0
0
0
Baking
To remove errors
and defects
Heated capacitor to remove
errors and defects
Temp
variation
Due to
machine
unit
2
8
1
16
10
Short
clearance,
welding
Rectification of
gap and welding
of lead on side
lead terminal on side edge
of capacitor and tapping on
rod
Welding
variation
Weaken the
bond
between
films
No standard
pitch
between
terminals
Current
and less
pressure
3
8
2
48
3
Preheating,
wax, paint
coating
Heating and
protection from
the atmosphere
Coated capacitor to
withstand the ambient
conditions
Undip and
temperature
variation
5
4
40
4
Labelling of lot
and number
specification
Indication of value for
specific function
Missing of
labels
4
2
2
16
10
Removal of
moisture
Defect and error proof
None
Due to
sudden
current cut
off
Machine
design and
operator
skills
None
2
Marking
Partial
coating and
less
protective
No
indication of
specification
of capacitor
None
0
0
0
0
Pressing
Masking
Spraying
Demasking
Post Curing
Capacitor rolled in bulk for
spray operation
None
Due to
masking
process
and design
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Visual
Inspection
Naked eye
inspection
Acceptance or rejection
Disjoint
To disjoint units
from rod
Disjointed units
None
Testing
Effectiveness of
each capacitor
Reliability of capacitor to
function
Cutting in length
and shape
capacitor in different cut
form on demand
Lead cut form
Final
inspection
Final quality
check
Quality effectiveness of
capacitor
Packaging
Packing of units
in box to
customers
Capacitors in box or packet
to delivery
Operator
performance
Acceptance
of rejected
capacitors
None
Acceptance
sampling
and skills
None
Untested
capacitor
Less
effectiveness
of capacitor
Burr
formation
on lead
No
functioning
of capacitor
Hold and
reprocessing
If rejected
full lot
becomes
scrap
Testing
unit in
machine
design
Excessive
powder
material
and cutter
in machine
Incoming
material
and
acceptance
sampling
None
None
None
2
3
3
18
9
0
0
0
0
2
4
3
24
7
1
8
5
40
4
3
2
3
18
9
0
0
0
0
7Table no.5
Elements
Machine/
tools
Product
attributes
Process
attributes
Winding
Stagger
Insulation
Resistance,
length and
width
Number of
turns in
stagger
Q
Masking
Rollers
and tapes
Electric
arc gun
None
Machine
design
Spray gun
air pressure
none
Spraying
Demask
Baking
Short
Clearance,
welding
Preheating
and
Coating
Marking
Visual
Inspection
Manually,
automatic
device
Oven
machine
Zinc and zinctin deposition
None
Current
leakage
Standard
time and
environment
Class
S&R
S
S&Q
None
Automatic
welding,
lead wire,
rods and
tapes
Powder
and tissue
pads
Marking
powder
Terminals
polarity and
strong bond
Current and
pressure
variation
Q
Powder
deposition
Current
variation
S&R
Labels and
code number
Machine
design
Q&S
Measuring
gauge and
tools
Quality
Sampling
and
observation
Q
Specification
tolerance
Evaluation
technique
Sample
Freq
Control
method
Reaction
plan
Stagger and
number of
turns for
tension
Micrometer,
I.R measuring
device and
Vernier scale
2/lot
Meet job
setter of
that process
Gap between
each capacitor
Gun pressure
and current
Visual
inspection
Pressure
Gauge, D
Amp/Volt
meter
Visual
inspection
1/roll
Statistical
quality
control/
Inspection
sheet
Manually
operated
Fine
surface of
side edges
Incoming
material and
dust
Bake time and
temperature
1/roll
5-10
/roll
Timer and
thermocouple
1/lot
Welding joint
and pitch of
capacitor
Micrometer
and testing
device
5-10
/lot
Sudden
current shut
off
Missing of
labels and
code
Maintenance,
inspection
1/lot
Operator
performance
Visual
inspection,
measuring
gauge
Visual
inspection
and skills
1/unit
1/unit
Good
masking
and mask
Productio
n Book
Stop the
machine
Stop the
machine
and inform
incharge
Contact
supervisor
Stop
machine
Visual
inspection
/machine
maintenan
ce
Regular
current
supply
Maintenan
ce of
machine
Meet line
supervisor
Operator
skills and
Ability
Double
inspection
by skill
operator
Stop the
machine
Report to
Maintenanc
e section
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Testing
Testing
machine
Effectiveness,
I.R and delta
Testing and
measuring
unit
Q
Measuring of
parameter
Visual and
inspection
sheet
1/lot
Lead cut
form
Cutter and
gauge
Terminal shape
or size
Cutting tool
Q
Uncut or burr
on capacitor
Cutter and
micrometer
1/lot
Final
inspection
Inspection
devices
and
gauges
Electrical
paraments
Q
Hold,
reprocessing
or rejection
Acceptance
and rejection
Sampling
1/lot
None
Check the
device
and
rework
Visual
inspection
Visual
inspection
and
measuring
gauge
Stop the
machine
and inform
incharge
Check
cutter and
rework
Recheck or
meet
supervisor
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Availability Analysis of Energy of Micro Hydro Power Plant with Screw
Archimedean Turbine in Indian Context.
Umanand Kumar, K.S.Chandel
Department of Mechanical Engineering, Dr. APJ Abdul Kalam UIT-RGPV, Jhabua, Madhya Pradesh,
INDIA.
*
Corresponding Author’s Email ID: umanand.singh4@gmail.com
ABSTRACT
The ability of renewable resources is to provide all of society's energy needs as soul for body.
The utilization of distributed energy resources is increasingly being pursued as an alternative to large
conventional central power stations. Discussions about common and future trends in renewable energy
systems based on reliability and maturity of each technology are presented. Micro-hydro power plant
based on Archimedes Screws turbine is a type of renewable energy power plant that is environment
friendly, easy to be functioned and low operation cost, etc. Turbine for the power plant is mixed flow
Archimedean turbine. However, several previous studies have not considered key complexities such as
dissimilarities in flows or turbine efficiency. Correspondingly, precise costing and return on speculation
data are often absent or deficient sensitivity analysis. Further research is essential to report the risks and
long-term reliability of installations, accompanied by the development of firm policy to direct and
incentivize sustainability gains in this area. A feasibility study has been carried ready for a micro
hydroelectric installation in India.
Keywords: micro-hydro power plant based on Archimedes Screw turbine.
1. Introduction:
Small scale hydropower constitutes a cost
Micro hydropower is an eco-friendly, fish
effective technology for rural areas in developing
friendly, non-polluting renewable source of
countries and, on the other hand, is a quiet
energy. It is the oldest renewable energy method
growing sector in India. [3] In the last decade,
for production of electricity known to mankind
problems related to energy crisis such as oil
mechanically. According to Kyoto protocol of
crisis, climatic change, electrical demand and
1997, most of industrialized countries agreed to
restrictions of whole sale markets have a risen
set some emission reduction target in order to
world-wide. These difficulties are continuously
maintain environmental & climatic equilibrium
increasing, which suggest the need of
of the world exposed by greenhouse effect, ozone
technological alternatives to assure their
depletion etc. To overcome these problems,
solution. One of these technological alternatives
renewable energy can be utilized to meet those
is generating electricity as near as possible of the
international targets. In current scenario, India is
consumption site, using the renewable energy
blessed with half a million locations where water
sources, that do not cause environmental
mills are serving for centuries. [2] If micro hydro
pollutions, such as wind, solar, tidal and micro
power plants are installed there, an energy
hydro-electric power plants. [4]
equivalent of 15000MW can be generated & 20
million Indians may get employed. There are
1.1 History of screw turbine:
nearly 5lac (approx.) potential sites over the
The screw turbine is a water turbine which
entire Himalayan region from Jammu & Kashmir
uses the principle of the Archimedean screw to
to north eastern states and can generate power as
convert the potential energy of water on an
much as of 25000 MW i.e. each can generate at
upstream level into kinetic energy. It may be
least 5KW. Till date only 25% (approx.) of the
compared to the water wheel, though the screw
total hydro power potential has been tapped to
turbine has a much higher efficiency.
generate power. Water mills are enough to run
The invention of the water screw is credited
TV, refrigerator, cooler, fan & light bulbs etc.
to the Greek polymath Archimedes of Syracuse
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in the 3rd century BC. A cuneiform inscription of
the Assyrian king Sennacherib (704 - 681BC)
has been interpreted by Dalley to describe the
casting of water screws in bronze some 350 years
earlier [8]. This is consistent with the classical
author Strabo who describes the Hanging
Gardens as watered by screws. A contrary view
is expressed by Dalley and Oleson in an earlier
review. The German engineer Konrad Kyeser, in
his Bellifortis (1405), equips the Archimedes'
screw with a crank mechanism. The
Archimedean screw is an ancient invention;
attributed to Archimedes of Syracuse (287–212
BC.), and commonly used to raise water from a
watercourse for irrigation purposes. [5] In 1819
the French engineer Claude Louis Marie Henri
Navier (1785–1836) suggested using the
Archimedean screw as a type of water wheel. In
1922 William Moerscher patented the
hydrodynamic screw turbine in America. [6]
1.2 History of Micro Hydro Power Plant:
The first hydroelectric scheme was
installed in Wisconsin in 1882; three years after
Thomas Edison invented the light bulb. Soon
after, hydropower became an important resource
for electricity generation. 20% of total electricity
consumed worldwide comes from hydro
electrical plants. In some countries hydropower
supplies 80% of electricity. This has generally
been supplied by larger hydroelectric schemes.
Interest in small hydro declined from its
historical roots due to the success of these large
hydropower plants in bringing down costs and
the success of other technologies such as nuclear
and diesel generation. However concern about
climate change, air quality and nuclear
generation and increasing costs of fossil fuel
based generation has renewed interest in small
hydro and other renewable forms of generation.
[7] The use of falling water as a source of energy
is known for a long time. In the ancient times
waterwheels were used already, but only at the
beginning of the nineteenth century with the
invention of the hydro turbine the use of
hydropower got a new impulse. Small-scale
hydropower was the most common way of
electricity generating in the early 20th century. In
1924 for example in Switzerland nearly 7000
small scale hydropower stations were in use. The
improvement of distribution possibilities of
electricity by means of high voltage transmission
lines caused fainted interest in small scale
hydropower. Renewed interest in the technology
of small scale hydropower started in China.
Estimates say that between 1970 and 1985 nearly
76,000 small scale hydro stations have been built
there. [8] In 1995, the micro-hydro capacity in
the world was estimated at 28 GW, supplying
about 115 TWh of electricity. About 60% of this
capacity was in the developed world, with 40%
in developing areas. Micro hydro plants that are
found in the developing world are mostly in
mountainous regions for instance in the some
places in the Himalayas as well as in Nepal where
there are around 2,000 schemes, including both
mechanical and electrical power generation. In
South America, there are micro-hydro programs
in the countries along the Andes, such as Peru
and Bolivia. Smaller programs have also been set
up in the hilly areas of Sri Lanka, Philippines and
some parts of China [9]
1.3 Working of screw turbine based plant:
The screw turbine is a water turbine which uses
the principle of the Archimedean screw to
convert the potential energy of water on an
upstream level into kinetic energy. It may be
compared to the water wheel, though the screw
turbine has a much higher efficiency. The turbine
consists of a rotor in the shape of an
Archimedean screw which rotates in a
semicircular trough. Water flows into the turbine
and its weights presses down onto the blades of
the turbine, which in turn forces the turbine to
turn. Water flows freely off the end of the turbine
into the river. The upper end of the screw is
connected to a generator through a gearbox. [5]
The Archimedean screw turbine is applied on
rivers with a relatively low head (from 1 m to 10
m) and on low flows (up to around 10 m3/s on
one turbine). Due to the construction and slow
movement of the blades of the turbine, the
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turbine is considered to be friendly to aquatic
wildlife. It is often labelled as "fish friendly".
The Archimedean turbine may be used in
situations where there is a stipulation for the
preservation and care of the environment and
wildlife. [5]
The low rotational speed and large flow-passage
dimensions of Archimedean screws also allow
fish to pass downstream through the screw in
relative safety. Archimedean screws are often
touted as ‘fish friendly’ hydro turbines, which
they undoubtedly are, though we at Renewable
First would say that all hydro systems should be
fish friendly, regardless of turbine type. In nonscrew hydro systems this just means well
designed intake screens and fish passes / by
passes would be required. Note that if upstream
fish passage is required at an Archimedean screw
site, a fish pass will be required. The final
advantage of the Archimedean screw is
simplified civil engineering works and
foundations. Because screws don’t have draft
tubes or discharge sumps, it means that the depth
of any concrete works on the downstream-side of
the screw is relatively shallow, which reduces
construction costs. The civils works are also
relatively simple, the main part being the loadbearing foundations underneath the upper and
lower bearings. In softer ground conditions the
load-bearing foundations can be piled. [6]
2. Analysis of Energy: [1]
The utility electricity sector in India has
one National Grid with an installed capacity of
330.86 GW as on 30 November 2017.
Renewable power plants constituted 31.7% of
total installed capacity. India is the world's third
largest producer and fourth largest consumer of
electricity. Electric energy consumption in
agriculture was recorded highest (17.89%) in
2015-16 among all countries. India has surplus
power generation capacity but lacks adequate
infrastructure for supplying electricity to all
needy people. In order to address the lack of
adequate electricity supply to all the people in the
country by March 2019, the Government of
India launched a scheme called "Power for
All". This scheme will ensure continuous and
uninterrupted electricity supply to all
households,
industries
and
commercial
establishments by creating and improving
necessary infrastructure. Its a joint collaboration
of the Government of India with states to share
funding and create overall economic growth.
2.1 Power Generation in India:S.
No
.
Type of Power
Generation
Power Capacity(MW)
1.
2.
Thermal Energy
Hyd Large
ro
Small
Ene
rgy
Wind Energy
Solar Energy
Biomass Energy
Nuclear Energy
Gas Power
Diesel Power
Total
1,92,971.5
44963.42
4389.55
Perc
enta
ge
(%)
58.3
13.6
1.3
32700.64
14771.69
8295.78
6780
25150.38
837.63
9.9
4.5
2.5
2
7.6
0.3
3.
4.
5.
6.
7.
8.
330860.51
Power Generation in India(%)
Thermal
Hydro
Wind
Solar
Biomass
Nuclear
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250000
200000
Power Capacity in India(MW)
Power Capacity
in India(MW)
150000
100000
50000
29.
A&N
Islands
Total
7.91
5.250
-------
19749.44
3803.678
895.40
Classification of small hydro power
projects in India
Class
Station capacity in KW
Micro hydro
Upto 100
Mini hydro
101 to 2000
Small hydro
2001 to 25000
2.2.1 Small hydel power condition in India:
A&N Islands
0
West Bengal
Uttarakhand
Uttar…
Tripura
Fig.-1
Describe the comparison of available power with
respect to small hydro power (only 1.3%)
Contributed.
2.2
Potential,
Installed
&
under
Implementation of Small Hydro Power (as
on31.03.2014):-[4]
State Wise Numbers And Aggregate Capacity Of SHP Projects(Upto 25 MW)
S.No. State
Potential Installed Implementation(MW)
(MW)
(MW)
1.
Andhra
978.40
221.030
32.04
Pradesh
2.
Arunachal
1341.38
103.905
22.23
Pradesh
3.
Assam
238.69
34.110
12.00
4.
Bihar
223.05
70.700
17.70
5.
Chhattisgarh 1107.15
52.000
115.25
6.
Goa
6.50
0.050
-------7.
Gujarat
201.97
15.600
-------8.
Haryana
110.05
70.100
3.35
9.
Himachal
2397.91
638.905
76.20
Pradesh
10.
Jammu & 1430.67
147.530
17.65
Kashmir
11.
Jharkhand
208.95
4.050
34.85
12.
Karnataka
4141.12
1031.658 173.09
13.
Kerala
704.10
158.420
52.75
14.
Madhya
820.44
86.160
4.90
Pradesh
15.
Maharashtra 794.33
327.425
43.70
16.
Manipur
109.13
5.450
2.75
17.
Meghalaya
230.05
31.030
1.70
18.
Mizoram
168.90
36.470
0.50
19.
Nagaland
196.98
29.670
3.20
20.
Orissa
295.47
64.625
3.60
21.
Punjab
441.38
156.200
19.45
22.
Rajasthan
57.17
23.850
------23.
Sikkim
266.64
52.110
0.20
24.
Tamil Nadu
659.51
123.050
------25.
Tripura
46.86
16.010
------26.
Uttar
460.75
25.100
------Pradesh
27.
Uttarakhand
1707.87
174.820
174.04
8.
West Bengal 396.11
98.400
84.25
Tamil Nadu
Sikkim
Rajasthan
Punjab
Orissa
Potential(MW
)
Nagaland
Mizoram
Implementati
on(MW)
Meghalaya
Manipur
Maharashtra
Madhya…
Kerala
Karnataka
Jharkhand
Jammu &…
Himachal…
Haryana
Gujarat
Goa
Chhattisgarh
Bihar
Assam
Arunachal…
Andhra…
0
1000
2000
3000
4000
5000
Fig.-2
Comments
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Describes the comparison of available potential,
projects
installed
&
projects
under
implementation of small hydro power plants in
various states of India. Haryana ranked 1st with
63.69 % followed by Rajasthan 41.71% and Goa
& Jharkhand ranked last with 0.77% and 1.94%
respectively as compared to projects installed &
potential available. West Bengal ranked 1st with
28.30% followed by Jharkhand with 17% &
Sikkim ranked last with 0.093% followed by
Madhya Pradesh with 0.66% as compared to
project
under implementation and rest of
available potential.
2.3 Established screw turbine power projects
in India:
S.N Place
Capac He Pow
o.
ity
ad
er
1.
Vadodra(Gujar 1 m3/s 5 m 33
at)
KW
2.
Indore(M.P.)
0.6m3/ 5 m 19
s
KW
3.
Pune(Maharas 1.4
15
50
3
htra)
m /s
m
KW
4.
Korba(Chhattis 0.3
15
20
3
garh)
m /s
m
KW
5.
Mechuka(Arun 0.3m3/ 15
25
achal Pradesh) s
m
KW
6.
Tato(Arunacha 0.3
15
20
3
l Pradesh)
m /s
m
KW
Fig.-3
3. Comparison Between various turbines: [10]
Turbine
Type→
Screw
Turbine
Efficien
cy
Up to
90%.Re
mains
constant
with
varying
load.
Output
Varies
proporti
onally to
inlet
flow
conditio
Cross
Flow
Turbine
Up to
85%.Re
mains
constant
with
varying
load.
Varies
proporti
onally to
inlet
flow
Kaplan
Turbine
Above
90%.Co
mes
down
drastical
ly at
varying
load.
Require
sa
constant
flow &
Head to
generate
Francis
Turbin
e
Above
90%.Co
mes
down
changes
at
varying
load.
Require
sa
constant
flow &
Head to
generat
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ns and
there is
no risk
of
damage
from
running
dry.
conditio
ns.
Generati
on
Capacity
Good for
5 KW to
500 KW
Good for
5 KW to
100 KW
Head
Best for
ranges
from 1
m to 10
m
Can
work
efficientl
y from
0.2 m3/s
to 10
m3/s
Factory
preassemble
d, less
civil
work.
Best for
ranges
from
1.75 m
to 40m
Can
work
efficientl
y from
0.04
m3/s to 5
m3/s
Requires
Penstock
& Draft
tube.
Installati
on
Period
Durabili
ty
2-3
months
5-6
months
Only
Water
required
Wear &
Tear
Negligib
le
Only
clear
water
required
High
Dischar
ge
Ease Of
Installati
ons
power.
Output
comes
down
exponen
tially at
part
inlet
flow
conditio
n.
Generall
y, does
not
perform
at low
flow in
summer
season.
Good
for 75
KW to 5
MW
Best for
ranges
from 2
m to 50
m
Can
work
efficient
ly from
3 m3/s
to 30
m3/s
Require
s
Penstoc
k&
Draft
tube.
Very
expensi
ve civil
work.
10-12
months
Only
clear
water
required
Very
high
e
power.
Up to
1000M
W
Best for
ranges
from 30
m to
800 m
Approx.
more
than 1m
Require
s
Penstoc
k&
Draft
tube.
Very
expensi
ve civil
work.
More
than 1
years
Only
clear
water
required
Very
high
Reliabili
ty
Mainten
ance
Environ
ment
Compati
bility
Excellen
t
Negligib
le
Fish
compati
ble
Good
Good
Good
Regular
Regular
Regular
Fish
incompa
tible
Fish
incompa
tible
Fish
incomp
atible
3.1 Objectives of Micro Hydro Power Plant
with Screw Turbine:
Eco-friendly in nature & have zero effect
on environment in the sense of pollution.
Cutting of trees and displacement of people
is not required.
Suitable for power consumption of small
villages or one or more than one families.
Sources-renewable energy resources.
Small canals, ponds & rivers etc. can be
utilized as resources.
Negligible maintenance & operation cost.
Fish friendly.
Easy & fast installation.
Very less civil work required.
High reliability.
Efficient for low and variable water heads
(Minimum 1m head).
Durability (mode of operation).
Low wear & tear.
Cavitations & erosion cannot affect the
turbine.
Efficiency will remain same with respect to
varying loads.
No control system necessary.
Efficiency is more as compared to water
wheels & small turbine.
Ultra long life at least 30 years.
CO2 reduction.
Natural flow of water i.e. no pressure built
up.
Wild life habitat will not be affected.
4. CONCLUSION:
Dam having higher water holding capacity for
large scale hydro power plants leads to many
drastic problems including people displacement,
deforestation, loss of agriculture land &
earthquakes. Viz., they are some examples, an
earthquake occurred at Latur & Ushmanabad
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(Maharashtra) due to KOENA dam and at
Jabalpur (MP) due to BARGI dam. Due to
INDRA SAGAR dam the Harshood place was
completely displaced & new Harshood was
established known as Chhannera. Only Due to
SARDAR SAROVAR dam at Narmada River
(Gujrat) more than 2 lakhs people were
displaced, 37 thousand hectares agriculture lands
& 10713 hectares deforestation took place etc.
There are many other several examples of these
kind of dams due to which the mentioned
problems are occurring.
India is blessed with abundant hydro electrical
potential, estimated 19749.44 MW, rank 5th in
the world, in terms of utilizable potential. But
when compared to other sources of micro hydro
power, Screw turbine is negligible in
consideration. It can give power to a particular
house or one or more families or even to small
villages. It has more efficiency and less
transmission losses as compared to other power
plants. According to survey, only 4389.55MW of
power is generated by small hydro power plants,
rather available potential is of thousands of MW
but could not utilized 22% (approx.) in total.
Some major states of India have even not
installed & implemented these small power
plants where potential is available. Using higher
efficiency of screw turbines, local power
requirement can be fulfilled, transmission losses
can be reduced, more employment can be
provided & nature can be preserved.
References:
(1.)
https://en.wikipedia.org/wiki/Electricity_sector_
in_India.
(2.) http://decarboni.se/publications/kyotoprotocol-1997
(3.) www.aprekh.org_files_RREST_AlokJindal
(4.) www.mnre.gov.in
(5.) http://en.wikipedia.org/wiki/Screw_turbine
(6.) http://www.renewablesfirst.co.uk/hydrolearning-centre/archimedean-screw/
(7.) http://greenbugenergy.com/get-educatedknowledge/the-history-of-hydropower
(8.)
http://josiah.berkeley.edu/2007Fall/ER200N/Re
adings/Micro_Hydro_2007.pdf
(9.)
https://energypedia.info/wiki/Micro_Hydro_Po
wer_(MHP)_Plants
(10.) www.jashindia.com
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Solar Energy in India and National Solar Mission: A Review
Mahendra Kumar Meena
Department of Political Science, SGGG Banswara Raj. (India)
Introduction
In global climate change regime, India has been
regarded as a prominent player due to its huge
population, developmental needs and great
economic potential. Since the Earth Summit
1992, India has been playing a very crucial and
pivotal role in shaping global environmental
policies. In 1972, at Stockholm conference,
Indian Prime minister Smt. Gandhi
had
described “poverty as a greatest polluter” and
thus underscored India’s preference to the
development to eradicate poverty. Thus, India’s
policy stand in international climate change
regime has been articulated around the equal
right of development for each individual. India
had successfully negotiated during the making
of United Nation Framework for Climate
Change(UNFCCC) and the inclusion of
“common but Differentiated Responsibility” in
article 7 of the Rio Declaration can be marked as
grand success for India and hence for all
developing nations.1
The principal of CBDR explicitly acknowledged
the historical responsibility of developed
countries in the degradation of the environment
and hence, assigned the primary responsibility to
the developed counties to avert climate change
and its adverse effects. To secure energy needs
for the development, India has always been in
denial mode to accept any binding commitment
to reduce its GHG emission despite being fourth
largest GHG emitter (2341000 kts Co2, 2013)2.
This Indian potion successfully went through
Kyoto Protocol (1997) under immense pressure
from the developed countries that India should
embrace binding mitigation commitments.
Under the furious pressure from the developed
countries, just before G-8 summit in Japan (June
2008), Indian PM Dr. Manmohan Singh
launched National Action Plan on Climate
Change (NAPCC) 3 The NAPCC , with the
outline of its 8 National Mission, was approved
by the Prime Minister’s Council on Climate
Change (PMCCC), a 26- member apex advisory
body, convened barely three week earlier
without a thorough discussion.4
In launching India’s National Action Plan on
Climate Change on June 30, 2008, the Prime
Minister of India, Dr. Manmohan Singh stated:
Our vision is to make India’s economic
development energy-efficient. Over a period of
time, we must pioneer graduated shift from
economic activity based on fossil fuels to one
based on non-fossil fuels and from reliance on
non-renewable and depleting sources of energy
to renewable sources of energy. In this strategy,
the sun occupies center-stage, as it should, being
literally the original source of all energy. We
will pool our scientific, technical and managerial
talents, with sufficient financial resources, to
develop solar energy as a source of abundant
energy to power our economy and to transform
the lives of our people. Our success in this
endeavor will change the face of India. It would
also enable India to help change the destinies of
people around the world.”5
It can be said that India has added renewable
energy as an important alterative to its energy
matrix to reduce GHG emission, which is mainly
dominated by coal-based power production, To
fulfill the international commitments made by
India through ‘Intended Nationally Determined
Contribution’(INDC)
to
the UNFCCC.
Enormous business opportunities further,
impetus the Indian policy makers to explore the
potential of alternative energy sources in context
of India’s energy security and to meet the huge
energy requirement to fuel India’s development.
India is geographically blessed with bright
sunlight in most of its part, throughout the year.
This nature’s blessing has tremendous potential
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to produce clean solar power. The National
Action Plan on Climate Change also points out:
“India is a tropical country, where sunshine is
available for longer hours per day and in great
intensity. Solar energy, therefore, has great
potential as future energy source. It also has the
advantage of permitting the decentralized
distribution of energy, thereby empowering
people at the grassroots level”. Based on this
vision a National Solar Mission is being
launched under the brand name “Solar India”6
The Eight National Mission
The operational content of the National Action
Plan lies in the eight different National Missions,
which were simultaneously announced by the
Indian government. These are as:
1. National Solar Mission
2. National Mission for Enhanced Energy
Efficiency
3. National Mission for Sustainable Agriculture
4. National Water Mission
5. National Mission o Sustainable Habitat
6. National Mission for sustaining the
Himalayan Ecosystem
7. National mission for A Green India
8. National Mission for strategic Knowledge for
Climate Change.
Each Mission says NAPCC, ‘will be tasked to
evolve specific objectives’ until financial year
2016-2017.It originally mandated the nodal
ministries
agencies
to
submit
eight
comprehensive mission documents by the end of
2008, to be approved by the PMCCC.7
JawharLal Nehru National Solar Mission
The National Solar Mission was launched on the
11th January, 2010 by the Prime Minister. The
Mission has set the ambitious target of deploying
20,000 MW of grid connected solar power by
2022 is aimed at reducing the cost of solar power
generation in the country through (i) long term
policy; (ii) large scale deployment goals; (iii)
aggressive R&D; and (iv) domestic production
of critical raw materials, components and
products, as a result to achieve grid tariff parity
by 2022. Mission will create an enabling policy
framework to achieve this objective and make
India a global leader in solar energy. Further,
Government has revised the target of Grid
Connected Solar Power Projects from 20,000
MW by the year 2021-22 to 100,000 MW by the
year 2021-22 under the National Solar Mission
and it was approved by Cabinet on 17th June
2015.8
Importance and relevance of solar energy
for India9
1. Cost: Solar is currently high on absolute costs
compared to other sources of power such as coal.
The objective of the Solar Mission is to create
conditions, through rapid scale-up of capacity
and technological innovation to drive down
costs towards grid parity. The Mission
anticipates achieving grid parity by 2022 and
parity with coal-based thermal power by 2030,
but recognizes that this cost trajectory will
depend upon the scale of global deployment and
technology development and transfer. The cost
projections vary –from 22% for every doubling
of capacity to a reduction of only 60% with
global deployment increasing 16 times the
current level. The Mission recognizes that there
are a number of off-grid solar applications
particularly for meeting rural energy needs,
which are already cost-effective and provides for
their rapid expansion.
2. Scalability: India is endowed with vast solar
energy potential. About 5,000 trillion kWh per
year energy is incident over India’s land area
with most parts receiving 4-7 kWh per sq. m per
day. Hence both technology routes for
conversion of solar radiation into heat and
electricity, namely, solar thermal and solar
photovoltaics, can effectively be harnessed
providing huge scalability for solar in India.
Solar also provides the ability to generate power
on a distributed basis and enables rapid capacity
addition with short lead times. Off-grid
decentralized and low-temperature applications
will be advantageous from a rural electrification
perspective and meeting other energy needs for
power and heating and cooling in both rural and
urban areas. The constraint on scalability will be
the availability of space, since in all current
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applications, solar power is space intensive. In
addition, without effective storage, solar power
is characterized by a high degree of variability.
In India, this would be particularly true in the
monsoon season.
3. Environmental impact: Solar energy is
environmentally friendly as it has
zero
emissions while generating electricity or heat
4. Security of source: From an energy security
perspective, solar is the most secure of all
sources, since it is abundantly available.
Theoretically, a small fraction of the tota
incident solar energy (if captured effectively)
can meet the entire country’s power
requirements. It is also clear that given the large
proportion of poor and energy un-served
population in the country, every effort needs to
be made to exploit the relatively abundant
sources of energy available to the country.
While, today, domestic coal-based power
generation is the cheapest electricity source,
future scenarios suggest that this could well
change. Already, faced with crippling electricity
shortages, price of electricity traded internally,
touched Rs 7 per unit for base loads and around
Rs 8.50 per unit during peak periods. The
situation will also change, as the country moves
towards imported coal to meet its energy
demand. The price of power will have to factor
in the availability of coal in international
markets and the cost of developing import
infrastructure. It is also evident that as the cost
of environmental degradation is factored into the
mining of coal, as it must, the price of this raw
material will increase. In the situation of energy
shortages, the country is increasing the use of
diesel-based electricity, which is both expensive
–costs as high as Rs 15 per unit -and polluting. It
is in this situation the solar imperative is both
urgent and feasible to enable the country to meet
long-term energy needs.
Objectives and Targets
The objective of the National Solar Mission is to
establish India as a global leader in solar energy,
by creating the policy conditions for its diffusion
across the country as quickly as possible The
Mission have adopted a 3-phase approach,
spanning the remaining period of the 11th Plan
and first year of the 12thPlan (up to 2012-13) as
Phase 1, the remaining 4 years of the 12thPlan
(2013-17) as Phase 2 and the 13th Plan (2017-22)
as Phase 3. At the end of each plan, and mid-term
during the 12thand 13th Plans, there will be an
evaluation of progress, review of capacity and
targets for subsequent phases, based on
emerging cost and technology trends, both
domestic and global. The aim would be to
protect Government from subsidy exposure in
case expected cost reduction does not
materialize or is more rapid than expected.
To achieve this, the Mission targets are:
To create an enabling policy framework
for the deployment of 20,000 MW of solar
power by 2022.
To ramp up capacity of grid-connected
solar power generation to 1000 MW within three
years –by 2013; an additional 3000 MW by 2017
through the mandatory use of the renewable
purchase obligation by utilities backed with a
preferential tariff. This capacity can be more
than doubled –reaching 10,000MW installed
power by 2017 or more, based on the enhanced
and enabled international finance and
technology transfer. The ambitious target for
2022 of 20,000 MW or more, will be dependent
on the ‘learning ‘of the first two phases, which if
successful, could lead to conditions of gridcompetitive solar power. The transition could be
appropriately up scaled, based on availability of
international finance and technology.
To create favorable conditions for solar
manufacturing capability, particular solar
thermal for indigenous production and market
leadership.
To promote programmes for off grid
applications, reaching 1000 MW by 2017 and
2000 MW by 2022.
To achieve 15 million sq. meters solar
thermal collector area by 2017 and 20 million by
2022.
To deploy 20 million solar lighting
systems for rural areas by 2022.
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Mission Strategy (phase 1 and 2)10
The Mission has strategy to achieve its targets
and objectives mainly through five ways;
A. Utility connected applications: constructing
the solar grid is the key driver for promoting
solar power would be through a Renewable
Purchase Obligation (RPO) mandated for power
utilities, with a specific solar component. This
will drive utility scale power generation,
whether solar PV or solar thermal. The Solar
Purchase Obligation will be gradually increased
while the tariff fixed for solar power purchase
will decline over time.
B. The below 80°C challenge –solar collector:
The Mission is setting an ambitious target for
ensuring that applications, domestic and
industrial, below 80°C are solarised.
C. The off-grid opportunity -lighting homes
of the power deprived poor: A key opportunity
for solar power lies in decentralized and off-grid
applications. In remote and far-flung areas
where grid penetration is neither feasible nor
cost effective, solar energy applications are costeffective. The Government has promoted the use
of decentralized applications through financial
incentives and promotional schemes. While the
Solar Mission has set a target of 1000 MW by
2017, which may appear small, but its reach will
add up to bringing changes in millions of
households.
D. Manufacturing capabilities: innovate,
expand and disseminate: Currently, the bulk of
India’s Solar PV industry is dependent on
imports of critical raw materials and components
–including
silicon
wafers.
Proactive
implementation of Special Incentive Package
(SIPs) policy, to promote PV manufacturing
plants, including domestic manufacture of
silicon material, would be necessary.
E. R&D for Solar India: creating conditions for
research and application A major R&D initiative
to focus: An ambitious human resource
development programme, across the skill-chain,
will be established to support an expanding and
large-scale solar energy programme, both for
applied and R&D sectors. In Phase I, at least
1000 young scientists and engineers would be
incentivized to get trained on different solar
energy technologies as a part of the Mission’s
long-term R&D and HRD plan.
The Road Map
The aspiration is to ensure large-scale
deployment of solar generated power for gridconnected as well as distributed and
decentralized off-grid provision of commercial
energy services. The deployment across the
application segments is envisaged as
Follows:
Table 1: The Solar Mission’s Proposed
Roadmap
Sr.No
Application
Segment
1
Solar
Collector
2
OffGridSolar
Application
Utility Grid
Power
3
Target
Phase I
(201013)
7
Million
Sq.
Metres
200MW
Target
Phase II
(2013-17)
Target
phase III
(2017-22)
15 Million
Sq.Metres
20 million
Sq.Metres
1000MW
200MW
10002000M
W
400010000M
W
20000M
W
Source:The Ministry of New and Reneable Energy,GOI,
JNNSM, N.Delhi, P.7
Economic Incentives: To achieve the leadership
position in solar energy economic incentives to
the solar industry is inevitable. Providing
adequate loan facility, setting up solar parks,
SEZ like facility for component manufacturing,
wavier in custom duty, ease of doing business,
single widow clearance, are some requirements t
boost solar revolution in India.
Importantly, Power purchase Agreement is
essential part of solar business to ensure the
economic viability of solar power. Again, the
falling prices of solar power are creating positive
sentiment and attracting investment to the solar
industry. Upendra Tripathy, formerly secretary
of the renewable energy ministry, “When we
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started, people didn’t believe that solar was for
real. They thought it was imaginary given that
the tariffs were at Rs18 per unit. They thought it
was a story which was being hyped. However, a
lot of people including companies and financial
institutions got interested. We called for open
bidding and whatever was happening
internationally, be it in terms of technology or
falling solar PV (photovoltaic) prices got
reflected here. With no cartels being formed, it
helped India,”11
The solar space has already seen a significant
decline in tariffs from Rs10.95-12.76 per kWh in
2010-11. The year 2017 has brought the prices
further down. India’s solar power tariff hit a new
low of Rs2.44 per unit on 12 May 2017 at the
auction of 500 megawatt (MW) of capacity at the
Bhadla solar park in Rajasthan.12 The decrease
in solar power prices attributed to the decision of
the Government of India to cover solar power by
Solar Energy Corporation of India Ltd(SECI)
under the ambit of tripartite agreement for
payment security against defaults by State
distribution companies13
Towards the Global Leader in Solar
Power
India launched an International Solar Alliance
(ISA) at the CoP21 Climate Conference, with an
announcement by Prime Minister Modi that the
revolution in the field would bring power to all
citizens, and create unlimited economic
opportunity. Over 100 countries falling between
tropics of Cancer and Capricorn have assured
their participation in the alliance for which India
will be providing the initial funding of Rs 175
References
1. Retrieved
from
http://www.un.org
/documents/ga/conf151/aconf151261annex1. htm
2. World
Bank
Data,
available
on
http://data.worldbank.org/indicator/SP.RU
R.TOTL.ZS/countries/1W8S?display=default
crore. The alliance brings together sun-rich
nations for a research and collaboration initiative
that has the potential to change the face of future
energy access. It will be a platform to benchmark
low-cost solar solutions and will provide unique
investment opportunity for the developing
world. The initiative places India in a more
assertive and constructive position on the
international stage, no longer merely accepting
the politics of climate change, but now shaping
them via its diplomatic and geopolitical
influence.14
Conclusion
Country like India has very much unbalanced in
electricity production. Production is less and
consumption is very much. Solar power is very
good option in India to increase power
production. This is also very good for our
environment
protection
and
economic
development. Solar power is unlimited source of
energy and our country also provide suitable
climate for this energy but we need some better
idea to increase efficiency and decrease
production cost. Our government launches some
schemes for production of solar power and
achieves some successes but we need education
and publicity in society for these schemes so that
people take some initiative for use renewable
energy as much as at a place of conventional
energy sources. Currently we are generating
4.59% of solar energy of total produced
renewable energy installed capacity in India. It
is very low in comparison of total installed
capacity of renewable energy and scope is very
much for this solar PV.
3.
4.
5.
6.
Prime minister’s Council on climate
change,GOI,2008,
NAPCCC,
N.Delhi,http:// pmindia.nic.in/pg01-52.pdf.
Praful Bidwai, “The politics of Climate
Change and the Global Crisis’, p.129,Orient
BlackSwan,2012
http://www.mnre.gov.in/filemanager/UserFiles
/mission_document_JNNSM.pdf
Ibid.
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7.
Praful Bidwai, “The politics of Climate
Change and the Global Crisis’, p.130,Orient
BlackSwan,2012
8. Ibid.
9. http://www.mnre.gov.in/filemanager/UserFiles
/mission_document_JNNSM.pdf
10. Ibid.
11. Solar Tariff ars heat up India, Livemint, 31
may 2017.
12. http://www.livemint.com/Industry/saGIF4
VEwvv38rf208tUAM/Solar-power-tarifffalls- further -to-Rs244-per-unit.html
13. Ibid.
14. Chetan Chauhan, “Pm Modi to launch Solar
Alliance in Paris Summit”,Hindustan
Times, Nov.30, 2015, N.Delhi
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Optimization Techniques Based Selective Harmonic Elimination for
Multilevel Inverter with Reduced Number of Switches
R. K. Kumawat*,1, D.K.Palwalia2
Department of Electrical Engineering
Rajasthan Technical University Kota, India
Corresponding Author:1rkkumawat.phd@rtu.ac.in, 2dkpalwalia@rtu.ac.in
Abstract
Multilevel inverter (MLI) is an alternative for high power and high voltage applications. It has low
switching stress on power switches, lower total harmonic distortion (THD), higher efficiency and low
Electromagnetic Interference (EMI). Higher number of power switches contributes complexity of
control and high cost. In this paper a seven-level MLI is proposed with reduced switch count and
improved performance. Selective Harmonic Elimination (SHE) that can be applied MLI ar desire
switching frequency offers elimination of harmonics in output voltage. Also, by using SHE technique
with cascade H-bridge multilevel inverters, the necessity of using filter in output can be minimized.
In this paper, SHE equation have been solved by using Genetic Algorithms (GA) and NewtonRaphson Method. It has been aimed to eliminated desire harmonic order at fundamental output
voltage and also have been analyzed and compared the harmonics.
Keywords—Multilevel inverter(MLI), THD, PWM, Full-bridge, Half bridge
INTRODUCTION
DC to AC power conversion play a crucial role
in recent years and implemented for high power
and high voltage application. It attracts in power
generation, energy transmission, distribution and
utility application. It has been widely applied in
variable frequency drive, power quality device,
UPS, HVDC transmission, inducting heating,
SVC, FACTS, marine propulsion, fuel cell, solar
cell. Concept of multilevel inverter is lucrative
solution in the medium and high voltage
application with high power conversion and
enhancement power quality [1–4]. it produce
output voltage waveform with control
frequency, amplitude and phase by controlling
the semiconductor switches [5–8]. A two-level
inverter use PWM operation with high switching
frequency and eliminate the lower order
harmonics. Issue with two level inverters is high
switching frequency loss due to unavailability of
high power high voltage semiconductor device.
MLI provides a cost-effective solution with low
distortion, reduced dv/dt stress, voltage limit
capability of semiconductor switches, better
harmonic profile, and high voltage capability. It
can operate at both fundamental switching
frequency and high switching frequency using
pulse width modulation scheme [9–11]. For high
voltage high power application such as power
quality, renewable energy resource, adjustable
I.
speed drive, micro grid and power system
control multilevel inverter received more
attention. It is commercialized as three basic
topology: neutral point clamped (NPC), flying
capacitor (FC), and cascade H- bridge (CHB)
[12–16]. Neutral point clamped is also known as
diode clamped multilevel inverter. DC bus
voltage split in N-level by series connected bulk
capacitor threw fast switching diode. Drawback
of NPC is higher number of diode and Dc-link
voltage balancing as the number of level increase
[17]. Capacitor clamped inverter required large
number of clamping capacitor to clamp the
output voltage by proper selection of capacitor
combination [18]. Cascade H-bridge inverter
consists of full bridge and half bridge module
with all source connected in series at each phase.
CHMLI have simplicity of control, lesser rating
and least number of power semiconductor
switches. It has no need of clamping diode and
voltage balancing capacitor. It has less common
node voltage, separate DC sources.
To control the output voltage and eliminate
harmonics a method is used for switching power
semiconductor switches. Method for proper
selection of switching angle such as space vector
modulation (SVM), space vector pulse width
modulation (SVPWM), sinusoidal pulse width
modulation (SPWM), selective harmonic
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elimination (SHE) has been conventionally used
[19-21].
SVM or CBPWM technique based on High
switching frequency modulation [22-24]. It leads
to high switching losses and lower order
harmonic producing high THD in output voltage.
Due to this side band round carrier frequency
appear. Low or fundamental switching
frequency modulation based SHE technique has
been developed for control of CHMLI. It has less
switching losses and few communications per
cycle. It maintains rapid power quality and direct
control over output voltage harmonic. Equation
produced by SHE-PWM are highly nonlinear
transcendental, depends on solving a series of
trigonometric equation and produced simple,
multiple or no solution for fixed value
modulation index. Thus, providing all possible
and analytical solution using less computational
complex method for SHE equation through
extensive range of modulation index 0 to 1, has
been big task for researcher.
Another approach has been implemented to
solve SHE equation based on converting
transcendental equation in to polynomial
equation [25-28]. Theory of symmetric and
resultants of polynomials has been suggested to
solve equation obtain from transcendental
equation. For this approach, proper initial guess
for switching angle and modulation index are
required. It is challenging task to guess initial
switching angle and modulation index for which
solution exist. That approach is unattractive
because degree of polynomial is in direct relation
with inverter level hence polynomial is very
complex,
numerical
difficulty,
and
computational burden.
In this paper, the researchers have performed
simulation for seven levels cascade H-bridge
multilevel
inverter, and used the selective harmonic
elimination PWM
switching method. PWM [29-30]. Selective
harmonic
elimination PWM switching method is utilized
for
controlling the gate signals of switching device.
Switching
angles are solved from the non-linear
transcendental
equations. For generating the optimized
staircase voltage
waveform, the optimized switching angles are
obtained
using by Newton-Raphson technique and
Genetic Algorithm
technique (GA). If we know the good initial
guesses then the results can be optimized well
more.
II. CONVENTIONAL CASCADE MULTILEVEL
INVERTER
Full bridge topology of cascade H-bridge with
four switches, a DC voltage source is used to
generate three levels square wave output voltage
waveform. Cascade multilevel consists of series
connection of multiple single phase modules
with symmetric and asymmetric manner [25].
Each module generates voltage level include
positive, negative and zero. Configuration of
cascade H-bridge is shown in fig.1
Overall output voltage of multilevel inverter is
given
V0 Vdc1 Vdc 2 Vdc 3 ...........Vdcn
(1)
If the entire Dc voltage source in each module
have equal the inverter is known as symmetric
multilevel. The number of output voltage steps
in symmetric multilevel inverter is
N step 2n 1
(2)
Maximum output voltage is due to the
communication of switches is:
Vo (max) n Vdc
(3)
Where n is the number of dc voltage source
If the entire DC voltage sources in each module
have unequal voltage level the inverter is known
as asymmetric multilevel inverter. It can provide
large number of output voltage steps without
increasing the number of switches. The number
of voltage steps and maximum output voltage are
given as follow:
N step 2n1 1
(4)
Vo(max) (2n 1) Vdc
(5)
p 1
If V 2 Vdc for p=1, 2, 3……, n
p
N step 3n
(6)
(3n 1)
Vdc
2
If V p 3 p 1Vdc for p=1, 2, 3……, n
Vo (max)
(7)
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313
S11
Edc1
Edc1
+
E01
+
S41
S21
S12
S32
S42
S22
-
+
E02
+
S1n
Edcn
S31
S3n
-
Eo
+
E0n
+
S4n
S2n
-
Fig.1. Configuration of cascade multilevel
inverter
III. ANALYSIS USING SELECTIVE HARMONIC
ELEMINATION
The selective harmonic elimination method is
also known as programmed PWM or
fundamental switching frequency method based
on harmonic elimination theory. Assuming
quarter wave symmetry and equal sources the
staircase, output voltage can be given by the
Fourier series expansion as follows:
(𝑎 cos(𝑛𝜔𝑡) +
𝑣 (𝜔𝑡 ) = 𝑎 +
𝑏 sin(𝑛𝜔𝑡))
(8)
Due to symmetricity, it does not contain even
harmonic component
𝑎 = ∫ 𝑣 (𝜔𝑡 )𝑑𝑡
(9)
𝑎 = ∫ 𝑣 (𝜔𝑡) cos(𝑛𝜔𝑡)𝑑𝑡
(10)
𝑏 = ∫ 𝑣 (𝜔𝑡) sin(𝑛𝜔𝑡)𝑑𝑡
(
11)
Hence Fourier expression can be written as
(𝑏 sin(𝑛𝜔𝑡))
𝑣 (𝜔𝑡) =
(12)
, ,
The value of bn component is compute as
(cos(𝑛𝛼 ) + cos(𝑛𝛼 ) +
𝑏 =
, ,
⋯ + cos(𝑛𝛼 ))
(13)
Subjected to 𝛼 < 𝛼 < 𝛼 < 𝛼 … <
𝛼 ≤𝜋 2
where ‘s’ is number of H-bridge connected in
cascade per phase and ‘n’ is order of harmonics.
If Vdc is input DC voltage for n single phase H-
bridge are connected per phase hence total
output voltage per phase is given by
𝑣 (𝜔𝑡) = 𝑣 (𝜔𝑡 ) + 𝑣 (𝜔𝑡) + 𝑣 (𝜔𝑡 ) +
⋯ + 𝑣 (𝜔𝑡 ) (14)
Non-liner fundamental equation for the odd
harmonic component is given by
(cos(𝛼 ) + cos(𝛼 ) + ⋯ + cos(𝛼 )) =
𝑣
(15)
Generally, for s number of switching angles, one
angle is used for desire fundamental output
voltage V1 and remaining (s-1) switching angle
are used to eliminate certain lower order
harmonics. The relation between fundamental
voltage and maximum fundamental voltage
V1max is given by modulation index ‘m’. The
modulation index is defined as the ratio of
fundamental output voltage V1 to maximum
fundamental
voltage
V1max.
Maximum
fundamental voltage is obtained when all
switching angle are zero.
𝑉
=
hence the expression for ‘m’
𝜋𝑣
𝑚=
4𝑠𝑣
𝑣 =𝑚
for 0<m≤1
Thus, nonlinear transcendental equation is
formed and after solving these equation
modulation index and switching angle (𝛼 𝑡𝑜 𝛼 )
characterizing the harmonic contain in output
waveform. To eliminate 3rd ,5th ,7th and 9th
harmonic 𝑣 , 𝑣 , 𝑣 and 𝑣 are set to zero.
(cos(𝛼 ) + cos(𝛼 ) + cos(𝛼 ) + ⋯
+ cos(𝛼 )) = 𝑠𝑚
(cos(3𝛼 ) + cos(3𝛼 ) + cos(3𝛼 ) + ⋯
+ cos(3𝛼 )) = 0
(cos(5𝛼 ) + cos(5𝛼 ) + cos(5𝛼 ) + ⋯
+ cos(5𝛼 )) = 0
(cos(7𝛼 ) + cos(7𝛼 ) + cos(7𝛼 ) + ⋯
+ cos(7𝛼 )) = 0
(cos(9𝛼 ) + cos(9𝛼 ) + cos(9𝛼 ) + ⋯
+ cos(9𝛼 )) = 0
(16)
The foremost objective is to minimizing the
nonlinear transcendental equation set, which is
express as
𝑓(𝛼 , 𝛼 , 𝛼 … … . 𝛼 )
Subjected to
𝛼 <𝛼 <𝛼 <𝛼 …<𝛼 ≤𝜋 2
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314
There are number of approach to solve nonlinear
transcendental equation. By converting
nonlinear transcendental equation in to
polynomial equation with resultant method all
possible solution for any number of level can be
compute when they exist. Total harmonic4.
distortion for corresponding solution compute by
%𝑇𝐻𝐷 =
× 100
(17)
IV. SOLVING SHE EQUATION USING
5.
OPTIMIZATION TECHNIQUE
In earlier section, SHE has been implemented on
CHMLI
configuration
and
nonlinear
transcendental SHE equations set have been
developed. In order get feasible solution during
completed range of modulation index (m) from
0 to 1 which give less %THD has been challenge
task for researchers hence deterministic and
stochastic algorithms have been developed. A
well-known Newton-Raphson (NR) method
comes under deterministic or iterative approach
and stochastic optimization techniques includes6.
Continuous-Genetic Algorithm (C-GA) and
Modified Species based Particle Swarm
Optimization (MSPSO). This section explains
newton Raphson method optimization algorithm
to solve SHE equation.
V. SOLVING USING NEWONS RAPHSON METHOD
Newton's method was first designated by Isaac a.
Newton in 1969, twenty years later Joseph
Raphson got close to Newton’s approach but b.
only for polynomials of degree 3,4,5…10. In
1740, Thompson Simpson explained NR methodc.
as an iterative method to solve optimization
problems by setting the gradient to zero. First
implementations of Newton’s method to solve d.
SHE equations to eliminate %THD in CHMLI is e.
by H. S. Patel & R. G. Hoft in 1973. Later in
literature several researchers have used Newton's
method to solve nonlinear transcendental SHE f.
equations. To solve nonlinear transcendental
equations Newton-Raphson method is one of the
g.
traditionally preferred iterative methods This
method based on calculus approach which is
powerful and fast-iterative method to reach
h.
global minimum. It begins with an initial guess
and generally converges at a zero. Basic
requirement of NR method is good initial guess.
If the initial guess is good, rate of convergence is
fast and computational time is reduced. The
steps
are
1.
2.
3.
involved in development of the algorithm
The switching angle matrix
𝛼 = [𝛼 𝛼 𝛼 𝛼 𝛼 ]
The nonlinear system matrix
𝐹 =
⎡ cos 𝛼
⎢cos
⎢
⎢cos
⎢cos
⎢
⎣cos
cos 𝛼
cos 𝛼
cos 𝛼
cos 𝛼
3𝛼
cos 3𝛼
cos 3𝛼
cos 3𝛼
5𝛼
cos 5𝛼
cos 5𝛼
cos 5𝛼
7𝛼
cos 7𝛼
cos 7𝛼
cos 7𝛼
9𝛼
cos 9𝛼
cos 9𝛼
cos 9𝛼
⎤
cos 3𝛼 ⎥
⎥
cos 5𝛼 ⎥
cos 7𝛼 ⎥
⎥
cos 9𝛼 ⎦
And its derivate
𝑑𝑓
𝑑𝛼
⎡ − sin
⎢ −3sin
⎢
= ⎢−5 sin
⎢−7 sin
⎢
⎣ −9sin
𝛼
− sin 𝛼
− sin 𝛼
− sin 𝛼
3𝛼
−3 sin 3𝛼
−3 sin 3𝛼
−3sin 3𝛼
5𝛼
−5 sin 5𝛼
−5 sin 5𝛼
−5 sin 5𝛼
7𝛼
−7 sin 7𝛼
−7 sin 7𝛼
−7 sin 7𝛼
9𝛼
−9 sin 9𝛼
−9 sin 9𝛼
−9 sin 9𝛼
−sin 𝛼
⎤
−3 sin 3𝛼 ⎥
⎥
−5 sin 5𝛼 ⎥
−7 sin 7𝛼 ⎥
⎥
−9 sin 9𝛼 ⎦
The corresponding harmonic amplitude matrix
𝑚𝜋
0 0 0 0
4
Above Following equation can be written as
𝐹 (𝛼) = 𝑇
Statement of algorithm can be written as
Guess the initial value for 𝛼 with 𝑗 = 0
Assume 𝛼 = [𝛼
𝛼 𝛼
𝛼
𝛼 ]
Calculate the value of
𝑓 (𝛼 ) = 𝐹
Linearize function 𝐹(𝛼) = 𝑇 about 𝛼
𝜕𝑓
𝐹 +
𝑑𝛼 = 𝑇
𝜕𝛼
𝑑𝛼 = [𝑑𝛼
𝑑𝛼 𝑑𝛼
𝑑𝛼
𝑑𝛼 ]
Calculate the value of 𝑑𝛼
𝜕𝑓
𝑑𝛼 = 𝐼𝑁𝑉
(𝑇 − 𝐹 )
𝜕𝛼
Updated initial guess values are
𝛼
= 𝛼 + 𝑑𝛼
Repeat the process for above equation until
equation 𝑑𝛼 satisfy the desire solution and
satisfy the following condition
0<𝛼 <𝛼 <𝛼 ≤𝜋 2
VI. GENETIC ALGORITHM TECHNIQUE
In order to ease the complexity of controlling
modern industries with multiple objectives and
constraints, many researchers have developed
𝑇=
ISBN-978-81-932091-2-7
315
biologically inspired algorithms and proved their
effectiveness of control compared to derivative
approaches. Genetic algorithm is one of the
Stochastic optimization (SO) methods to solve
nonlinear transcendental equations effectively.
GAs is a subclass of Evolutionary computing
and are random search algorithms. Though, all
minimum seeking algorithms uses the same
basic approach of heading downhill from an
arbitrary starting point but they differ in deciding
in which direction to move and how far to
move (Davis 1991). After Successive
improvements like increasing the speed of
search process with good intelligence, without
trapping at local minimum, powerful and widely
accepted biologically inspired algorithm of
Genetic Algorithm has been proposed by John
Hallond in 1975 and finally it has been
popularized by one of his student Goldberg who
has solved the complex problem of control of
gas-pipe line transmission for his dissertation
work (Chamber 1995). Later it has been
successfully implemented for solving number of
engineering optimization problems due to the
advantages such as Optimization with
continuous or discrete variables, no need of
calculus information, capability of dealing with
a large number of variables, well suited for
parallel computers, ability to find optimum
global minimum instead of local minimum even
in most complex objective functions
(Sivanandam & Deepa 2011); (Deb 2001).
Start
Find No. of Variable
Set population size
Evaluate fitness function
If No. of iterations
less then 100
No
Yes
GA operation
No
If cost function
less then 1
Yes
stop
VII. SIMULATION RESULTS
All simulating results and work is done on
MATLAB 2012a package. Selective harmonic
elimination
pulse
width
modulation (SHE-PWM) switching method is
used for controlling the cascade multilevel
inverter, and the nonlinear transcendental
trigonometric Eq. 16 and objective fitness
function are solved and optimized by applying
both
of proposed newton-raphson (NR) methods and
GA techniques respectively.
In this work, Continuous Genetic Algorithm has
been used to solve nonlinear transcendental SHE
equations during whole range of MI from 0 to 1.
Steps involved in Continuous GA are as follows
Step 1: Defining of optimization variables, cost
function, cost. (cost minimization).
Step 2: Generation of initial population.
Step 3: Fitness/Cost evaluation.
Step 4: Selection of Mates.
Step 5: Mating.
Step 6: Mutation.
Step 7: Convergence check.
Step 8: Repeat step (2) to step (7) until
requirements met.
Detailed explanation of algorithm is presented in
(Ozpineci et al. 2005).
Figure 2: Switching angles versus modulation
index for NR Method
The simulating results are discussed for singlephase inverter with separate equal and constant
dc sources. Each separate source has 24 volts,
and case is studied for modulation index range
from 0 to 1. Optimized results for cascade
multilevel inverter are obtained at particular
modulation indexes where the THD is lowest.
Modulation index versus switching angles,
ISBN-978-81-932091-2-7
316
8
10
12
14
16
18
20
% THD
Modulation Index
Figure 4: THD versus modulation index for NR
Method
Figure 5: THD versus modulation index for GA
Method
VIII. CONCLUSION
New configuration of cascaded multilevel
inverter has been proposed in this paper with a
view to obtain all possible additive and
subtractive combinations of the input DC level
in the output voltage waveform. Suggested
topologies need fewer switches and gate driver
circuits with minimum standing voltage on
0.9145
0.8214
5.33
6.19
37.27
24.46
23.32
6
12.69
0
4.82
0.2
0.97
0.4
GA
0.6
62.67
0.8
54.41
1
TABLE I
Switching Angles, THD and Computational Time
Figure 3: Switching angles versus modulation
index for GA Method
34.83
12
20.93
10
11.66
8
0.755
6
Modulation Index
NR
4
𝛼
2
𝛼
0
𝛼
0
𝛼
20
𝛼
40
%THD
60
Switching Angle
mi
alpha1
alpha2
alpha3
alpha4
alpha5
80
Modulation
Index
100
Computational Time
(secs)
switches for realizing Nstep for the load.
Therefore, the proposed topology results in
reduction of installation area and cost and has
simplicity of control system.
The Newton-Raphson and GA techniques for
harmonics elimination have been compared for
equal and constant dc source cascade H-bridge
inverter. Optimized angles have been obtained
by
Method
THD, and frequency versus are shown in Fig.2Fig. 5.
solving the SHE problem. The total harmonic
distortion (THD) for voltages have been reduced
in more amount using GA techniques rather than
Newton-Raphson technique, but NewtonRaphson takes time lesser than GA.
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System, vol. 6, pp. 239-243, March 2017.
[29] T. Lakshmi, N. George, S. Umashankar, and
D. Kothari, “Cascaded seven level inverter
with reduced number of switches using level
shifting PWM technique,” in Power, Energy
and Control (ICPEC), 2013 International
Conference on, 2013, pp. 676–680.
[30] N. A. Rahim, K. Chaniago, and J. Selvaraj,
Single-phase seven-level grid-connected
inverter for photovoltaic system,” Industrial
Electronics, IEEE Transactions on, vol. 58,
no. 6, pp. 2435–2443, 2011.
BIOGRAPHIES
R.K.Kumawat B’91, in Sikar
Rajasthan received the B.Tech
degree in Electrical Engineering
from Jaipur National University,
Jaipur,
India,
in
2011;
the M.Tech degree in Power System from
University College of Engineering, RTU,
Kota, India in 2014.Where he has been
pursing Ph.D degree in Power Electronic
and Drive since 2014. His research interest
includes power electronic for renewable
energy, multilevel converters and electrical
machine.
Dr.D.K.Palwalia, B’76, in Ajmer
Rajasthan have received his B.Tech
& M.Tech in 96 and 98 respectively.
He obtained his Ph.D form IIT
Roorkee
in 2010. He is working as Associate
Professor in Electrical Engineering
Department at University College of
Engineering, RTU, Kota. His research
interest are power electronic & Drive,
renewable energy, induction generator and
digital control design
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Techno-economic Analysis of Solar Photovoltaic Cooling System: an
analysis in four different climates in India
B.L.Gupta
Department of Mechanical Engineering, Govt. Engineering College Bharatpur (Raj.)
Email: blgbharatpur@gmail.com, M – (0) 9414810114
Abstract
This study covers the techno- economic analysis of solar energy-based cooling system using photovoltaic (PV)
technology for an office building located in four different climatic zones of India using simulation techniques.
For Cooling technology multiple options have been considered; Mono crystalline, Poly crystalline and thin film
cells. The building geometry, user profile and construction have been considered identical for chosen locations in
four climatic zones; Ahmedabad from hot and dry zone, Bangalore from moderate zone, Chennai from warm and
humid zone and Delhi from composite zone. The building modeling has been done using Google sketch up
software while the simulation has been carried using TRNSYS v-17 software. The cooling load of the building
varies with the climatic zones. Technically solar photovoltaic cooling system is possible having the solar fraction
in the range of 0.24-0.57 and Primary energy savings reaches 57 % in the hot and dry climate. In this way the
carbon dioxide (CO2) emission is also avoided. The payback periods, are higher in all the climate zones and the
least being 14.23 years for the hot and dry climate. When PV based systems are optimally used with net metering
provisions during the non-cooling periods then the payback period is 4-6 years for all climate zones. On the basis
of techno-economic analysis, it is recommended that considering the prevailing costs and performance levels, net
metering scheme should be immediately introduced in all states.
1. Introduction
To improve the thermal comfort conditions,
particularly in the summer season, there is
growing demand of conventional vapour
compression air conditioners. This growing
demand not only increases electricity
consumption but also global warming. Building
architectural characteristics and trends like
increasing ratio of transparent to opaque
surfaces in the building envelope to even popular
glass buildings has also significantly increased
the thermal load on the air conditioners
(Henning 2007).
The
conventional
vapour
compression
refrigeration cycle driven by grid electricity
increases the real cost of development. Firstly, it
strongly increases the consumption of electricity
and fossil energy. Energy sources based on fossil
fuels such as coal, oil, gas, and nuclear energy
sources etc., are either diminishing or are scarce
in nature, location and volume hence a serious
energy deficiency threat. In addition, it causes
serious environmental hazards by releasing
poisonous gases.
One of the major
environmental issues is acid rain resulting from
sulphurous gases emitted from power plants,
killing sensitive living species, disrupting
complex soil chemistry and affecting human
health. Greenhouse gases such as CO2 (by
product of combustion of fossil fuels), CH4,
N2O, and halocarbons released from human
activities absorb outgoing energy from the earth
and cause warming effects. Secondly, the
refrigerants like chlorofluocarbons (CFCs),
hydrochlorofluorocarbons
(HCFCs)
and
hydrofluocarbons (HFCs) are also responsible
for ozone depletion and global warming (Fan et
al. 2007). UN Intergovernmental Panel on
Climate Change (IPCC) warned that the average
global temperature may increase by 1.4-4.5 K till
2100. The average global temperature has
already risen by 0.6 K in the last century. In such
a scenario, Kyoto Protocol adopted in 1997, a
legally binding agreement under which the
industrialized countries agreed to reduce their
collective greenhouse gases by 5.2% compared
to the year 1990. In Europe HFC-134a was
banned for the air conditioning units in the new
cars starting from 1 January 2009 (Kim 2008).
In the present work parametric study and
performance analysis of solar photovoltaic
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cooling systems has been performed considering
the annual solar fraction and relative primary
energy savings. Three types of photovoltaic
panel have been taken for the solar photovoltaic
cooling (mono crystalline, poly crystalline and
thin film). For performance analysis,
Ahmedabad represents hot and dry climate,
Bangalore represents moderate climate, Chennai
represents warm and humid climate and Delhi
represents composite climate. The cooling load
of the building is different due to the climatic
condition and consequently the system
performance also differs. Financial viability of
the cooling system has been examined through
comparison with the energy consumption of
conventional cooling system for producing the
same cooling effect. Payback period is also
calculated.
2. Solar photovoltaic cooling systems
This system is simulated using TRNSYS
program v-17. In this cooling system the
packaged terminal air conditioner of 10 TR has
been chosen operated by the electrical power
supplied by the photovoltaic panel. If the power
generated by the photovoltaic panel is less than
required by the air conditioner then the
remaining power will be taken from the grid. If
the power generated by the photovoltaic panel is
greater than required by the air conditioner then
the remaining power will be supplied to the grid.
The system is simulated using the three types of
panels, mono-crystalline, polycrystalline and
thin film cell.
PV PANEL
Building Type56
Weather data Type-15
INVERTER
AIR CONDITIONER
Solar Air Conditioning.
The building being used in this research work is
an office building with square envelope of 15m
length and 15 m width. The height of the
Building is 3.5 meters and total floor area is 225
m2. Building is divided in the five zones having
orientation towards north. The entire building is
used for office purpose in the day time only and
whole area is conditioned. Windows on all four
sides together constitute a WWR of 26%. The
detail dimension of Building is shown in the
Table 2 and in the Fig 2. Building envelope
consists of the parts of building that separate the
controlled indoor environment from the
uncontrolled outdoor environment. It includes
the walls, floor, roof and fenestration (windows,
door). Walls, roof and window thickness and
materials are selected such that the U-value of
construction meets the ECBC requirement.
Table 3 shows the complete details of U-value
used here.
Fig.2:3 D view of Building
Table 2 : Building Zone area and Internal
load on Building
S
.
N
o
1
2
3
MIXTURES
PSYCHROMETRIC CHART
THERMOSTATE
Fig 1 Schematic of Solar Photovoltaic Cooling
System
3. Specification of Building coupled with
2
3
Compon
ent
Zone
Vol.(m3
)
Zone
Area(m2
)
WWR
(%)
Infiltrati
on
(ACH)
Ventilati
on(ACH
Wes
t
Zon
e
143.
64
Nor
th
Zon
e
143.
64
Core
Zone
212.9
4
East
Zone
143.6
4
South
Zone
143.64
60.84
41.04
41.0
4
41.0
4
41.04
-
27
27
23
27
0.2
0.2
0.2
0.2
0.2
0.75
0.75
0.75
0.75
0.75
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6
7
10.8
10.8
10.8
10.8
10.8
8
6
6
6
6
80
80
80
80
80
09001800
09001800
090
0180
0
090
0180
0
09001800
4.
Result and Discussion
4.1 Annual cooling load analysis
The cooling load of the five zone buildings
having a conditioning area of 225 m2 are
determined using TRNSYS program. From the
building cooling model, the cooling load can be
determined partly as infiltration gain, ventilation
gain, sensible gain and latent gain. The total
cooling load of a building is the summation of
infiltration, ventilation, internal gain and solar
gain through walls, windows and roof. The
infiltration load is due to cracks, fenestration in
the walls and roof, whereas ventilation load is
due to fresh air supplied to the building. The
person sitting inside the building also has a part
of sensible and a part of latent heat load.
Lighting, equipment, is also responsible for the
cooling load. The major part of the load is by
solar gain through the walls and windows
depending on the U value of the construction
materials. In this study the building load is
calculated by using TRNSYS simulation
program for four cities situated in four different
climate conditions.
Fig.3 shows the annual cooling demand and
peak cooling load for the different cities selected
from different climate zones. It is clear that the
peak cooling load is 31.59 kW for Delhi
(composite climate) whereas the lowest 20.85
kW is for Bangalore (Moderate climate) while
annual cooling demand per square meter of
building area is highest 225.64 kWhth/m2 for
Chennai (Warm and humid). This indicates that
the peak cooling load is higher in composite
climate (Delhi) and hot and dry climate
(Ahmedabad) because the variation of
temperature is higher there resulting in the peak
load but the total cooling load is highest for
warm and humid climate (Chennai) where the
warm and humid climate increases the latent
heat load than others resulting in highest cooling
demand. Hot and dry climate (Ahmedabad) is
the second highest cooling load city because of
longer cooling period.
Annual Cooling Demand
(kWhth/m2)
225.64
250
200
150
100
50
100
194.72
130.85
31.07
20.85
155.92
80
60
28.23
0
40
31.59
20
Peak cooling load kW
5
)
LPD(W/
m2)
People(
Nos.)
Equip.
Load(W
)
Schedul
e(Time)
Annual CoolingDemand
kWhth/m2
4
0
Fig.3:
cooling loads and peak cooling load
Annual
4.2 Solar Fraction
It is the ratio of the annual cooling produced by
the solar to the total annual cooling demand of the
building.
Solar Fraction
Annual cooling produced by solar absorption chiller
=
Annual coling demand of building
Fig 4 a-c shows the variation of annual solar
fraction with the photovoltaic area for the three
types of panel Mono, Poly and Thin film
respectively.
It is clear from the fig 4 a-c that as the area of
photovoltaic panel is increased the annual solar
fraction also increases for all type of panels and
climate. The annual power generation directly
depends on the area of PV panel so any increase
in the PV area increases the power generation and
more power directly supplied to the cooling
system enhances the solar fraction. The highest
solar fraction (0.37-0.57) for mono-cells is
observed for the hot and dry climate due to higher
power generation, and good matching between
the cooling load and power generation in the day
time. The lowest solar fraction (0.32-0.49) for
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Hot and dry (Ahmedabad)
Moderate (Bangalore)
Warm and humid (Chennai)
Composite (Delhi)
Solar Fraction
0.60
0.45
0.30
0.15
0.00
70
80
90
100
110
PV Area m2
(a)
Mono
Hot and dry (Ahmedabad)
Moderate (Bangalore)
Warm and humid (Chennai)
Composite (Delhi)
Solar Fraction
0.60
0.45
0.30
0.15
0.00
70
80
90
PV Area
100
110
m2
(b)
Hot and dry (Ahmedabad)
Moderate (Bangalore)
Warm and humid (Chennai)
0.60
Solar Fraction
mono-cells is observed in the warm and humid
climate due to very high cooling load 225
kWhth/m2 and high annual power consumption of
17912 kWhel.
For moderate and composite climate, the annual
solar fraction ranges between 0.33-0.51, and 0.350.54 respectively. The value of solar fraction for
the composite climate is also higher because of
the good matching between the power generation
and the cooling demand in the summer months.
The annual solar fraction is lower for the thin film
cells because of the low efficiency of cells for all
type of climates. The annual power generation for
the poly cell is higher than the thin film but lower
than the mono-cell so the annual solar fraction for
poly-cell lies between the mono and thin film
cells.
0.45
0.30
0.15
0.00
70
80
90
100
110
PV Area m2
(c)
Thin film
Fig.4 a-c Annual solar fraction
4.3 Primary Energy Savings
Primary energy consumption is calculated from
energy consumption of the cooling systems by
dividing it to the conversion factor 0.36 [Eicker
et al.]. In the solar photovoltaic cooling system,
the electrical consumption is done by the
compressor, condenser fan and blower. The
primary energy savings is the difference
between the primary energy consumption by the
solar photovoltaic cooling system and the
primary energy consumption
by the
compression-based cooling system operated by
grid power.
Fig 5 a-c shows the primary energy savings for
the mono, poly and thin film cell respectively. It
is clear from the graph that the primary energy
savings increase with the PV area for all the
climates and type of PV panels. The highest
primary energy saving is for the mono cell and
lowest for the thin film cells, and for poly cells
it is between mono and thin film.
The primary energy savings are highest 36%56% for the hot and dry climate and lowest for
the warm and humid climate, the reason is same
as in the annual solar fraction. The cooling
demand is very high for the warm and humid
climates and power generation is lesser than hot
and dry climates resulting in the low primary
energy savings in the warm and humid climates,
i.e., 31%-49%. The range of primary energy
savings in the moderate climate and composite
climate are 35-55% and 34-54 % respectively.
Poly
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periods then the payback period is in the range
of 4-6 years.
Hot and dry (Ahmedabad)
Moderate (Bangalore)
60
Primary Energy
Savings(%)
Hot and dry (Ahmedabad)
Moderate (Bangalore)
45
Payback period (Years)
40
30
30
15
20
0
10
70
80
90
100
110
0
Mono
PV Area m2
(a)
Mono
Thin
(a)
Hot and dry (Ahmedabad)
Hot and dry (Ahmedabad)
Moderate (Bangalore)
Moderate (Bangalore)
60
Poly
Type of PV panel
Payback period (Years)
Primary Energy
Savings(%)
10
45
8
30
6
15
4
2
0
70
80
90
100
110
(b)
Poly
(b)
Primary Energy
Savings(%)
30
15
0
80
90
Thin
Fig.6 Payback periods (a) Solar photovoltaic (b)
Solar photovoltaic (with net metering)Collector/PV area-90m2
45
70
Poly
Type of PV panels
Hot and dry (Ahmedabad)
Moderate (Bangalore)
Warm and humid (Chennai)
60
0
Mono
PV Area m2
100
110
PV Area m2
(c)
Thin
Fig.5 a-c Primary energy savings
4.4 Payback Periods:
Fig 6 a and b shows the payback photovoltaic
cooling systems based on the present cost
structure in India [see appendix]. It is clear from
the graph that the payback is higher. In the solar
photovoltaic cooling system, the lowest payback
period is observed for the hot and dry climate
that is 14.23 years with the thin film cells. If the
PV based systems are optimally used with net
metering provisions during the non-cooling
5. Conclusions
In the solar photovoltaic cooling system, the S.F.
is highest for hot and dry climate (Ahmedabad)
and lowest for warm and humid climate
(Chennai) due to higher cooling demand in
Chennai. Primary Energy Savings increases
rapidly with the PV area. Solar photovoltaic
cooling system (without net metering) has a high
payback period. Lowest payback of 14.23 years
is found for hot and dry climate (Ahmedabad)
due to good combination of cooling demand and
annual electricity generation, for moderate
climate (Bangalore) payback is highest 34 years.
when PV based systems are optimally used with
net metering provisions during the non-cooling
periods then the payback period is 4-6 years for
all climatically zones. In this way this cooling
system avoided a large part of CO2 emission.
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hospital” Energy and Building, Vol. 42, pp.
265-272.
6. References
1.
Central Electricity Regulatory Commission
New Delhi.
2. Eicker U., Colmenar-Santos A., Teran L.,
Cotrado M. 2014 “Economic evaluation of
solar thermal and photovoltaic cooling
systems through simulation in different
climatic conditions: An analysis in three
different cities in Europe” Energy and
Buildings, Vol. 70, pp. 207-223.
3. Eicker U., Pietruschka D. 2009 “Design and
performance of solar powered absorption
cooling systems in office buildings” Energy
and Building, Vol. 41, pp. 81-91.
4. Energy Conservation Building Code
(ECBC) User Guide, Bureau of Energy
Efficiency (2007).
5. Hartmann N., Glueck C. Schmidt F.P 2011
“Solar cooling for small office buildings:
Comparison of solar thermal and
photovoltaic option for two different
European Climates.” Renewable Energy,
Vol. 36, pp. 1329-1338.
6. Henning H.M. 2007 “Solar assisted air
conditioning of buildings – an overview”
Applied Thermal Engineering, vol. 27 pp.
1734–1749.
7. Kim D.S., Infante Ferreira C.A. 2008 “Solar
refrigeration options – a state-of-the-art
review” Int. Journal of Refrigeration, Vol.
31, pp. 3–15.
8. Lazzarin R.M. 2014 “Solar cooling: PV or
thermal? A thermodynamic and economical
analysis” Int.Journal of Refrigeration,
Vol.39, pp. 38-47.
9. Mateus T., Oliveira A.C. 2009 “Energy and
economic analysis of an integrated solar
absorption cooling and heating system in
different building types and climates”
Applied energy, Vol. 86, pp. 949-957.
10. Tsoutsos T., Aloumpi E., Gkouskos Z.,
Karagiorgas M. 2010 “Design of a solar
absorption cooling system in a Greek
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Effect of Renewable Energy on Green House Effect and Environment
: A Study
Ravi Prakash Maheshvari, Akhil Nema
Civil Engineering Department, Govt. Engineering College Banswara, Raj. (India)
Corresponding Author: rpmaheshvari@gmail.com
Abstract
Our earth is enclosed by the cover of some gases which retains the heat of rays coming from the sun
which increases the the temperature of the earth, this process is called as Green House Effect. This
effect increases the temperature and creates some problems like global warming, skin diseases and
sea level rise. Renewable energy is basically generated from renewable resources such as wind, rain,
tides, waves, sunlight, geothermal that is collected from renewable resources. Renewable energy
often provides energy in four important areas electricity generation, air heating and water heating
cooling, transportation, and rural energy services. In this study, it is observed that the renewable
energy may be a good solution for the harmful and dangerous effects of greenhouse gases.
Keywords: Renewable Energy, Green House Effect, Environment, Solar, Wind, Global Warming.
The bulk of harmful carbon dioxide emissions
appear from combustion of fossil fuels,
1 Introduction
In our society the production and consumption
of electricity is increasing day by day because
it has become the major requirement for us.
There are more ways in which we are using
that electricity such as television, computers,
refrigeration etc. This electric energy is
producing by coal, diesel and many renewable
sources such as solar, wind, biomass etc.
Today fossil fuels are the major input for the
production of the electricity which are emitting
some harmful agents to the environment like
carbon dioxide and methane. Refrigeration and
burning of fossil fuels gives chlorofluoro
carbon type harmful chemicals to the
environment. These harmful chemicals and
agents are the main causes of environment
degradation and Green House Effect.
A greenhouse gas is a agent which emits and
An environmental gas which emits and absorbs
radiant energy within the thermal infrared
range is a greenhouse gas. This creates the
greenhouse effect. The primary gases in Earth's
atmosphere responsible for greenhouse effect
are water vapour, carbon dioxide, methane,
nitrous oxide, and ozone. The present average
temperature is 150c while it would be -180c
without these gases. All the energy generation
and consumption processes and human
activities has created that the atmospheric
concentration of carbon dioxide (CO2), from
280 ppm in 1750 to 406 ppm in early 2017.
primarily coal, oil, and natural gas, with
relatively modest supplementary assistance
coming from deforestation, changes in land
exploit, soil erosion, and farming.
If the emissions of green house gases will rise
continuously at the present rate then it is
estimated that the temperature will increase
chronologically till 2047 with dangerous and
injurious effects on humans, plants and bio life.
Some researchers studied and said that humans
are responsible for global warming and green
house effects because deforestation and fossil
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fuel combustion emits the carbon dioxide and
other gases which are increasing temperature
of environment and magnitude of green house
gases, this process is known as Green House
Effect. This effect is warming the earth surface
and affecting the environment. Major green
house gases are carbon dioxide, methane and
nitrous oxide. The contribution of green house
gases in atmosphere are as follows.
Compou Formu
nd
la
Water
vapour
and
clouds
Carbon
dioxide
Methane
Ozone
Contribut
ion
H20
Concentrat
ion in
atmospher
e (ppm)
10-50,000
Co2
400
9-26%
Ch4
O3
1.8
2.8
4-9%
3-7%
36-72%
When the temperature increases the
concentration of greenhouse gases is increase.
This increment in temperature is due to
combustion of fossil fuels, refrigeration and
power generation in power plants.
The concentrations of carbon dioxide,
methane, and nitrous oxide are all known to be
increasing and in recent year, so their
greenhouse
gases,
principally
chlorofluorocarbons (CFCs), have been added
in significant quantifies to the atmosphere.
Noam lior (2008) studied on renewable energy
about the present situation and future demand.
In that research the work was about the recent
estimates and forecasts about the oil, gas and
coal resources and their reserve/production
ratio, nuclear and renewable energy potential.
The work is also consisting of impact of
rapidly growing economies of highly
populated countries and the effect of global
warming is also discussed. The research work
concluded that the ways to resolve the problem
of the availability, cost and sustainability of
energy resources alongside the rapidly rising
demand.
Joshua M. Pearce (2012) reviewed and
analysed the challenges that nuclear power
must overcome in order to be considered
sustainable in this paper. This study comprises
of the limitations of nuclear energy as a
sustainable energy resource. So, this study
concluded that if the fossil fuel combustion is
replaced by nuclear energy then it is required
to improve the technology to reduce
greenhouse gas emissions. The technology
should improve to diminish the risk in adopting
the nuclear energy. The radioactive disposal
that is harmful to the environment should be
minimise for the duration of mining and other
works. The elimination of radioactive disposal
that is harmful to the environment should be
minimise for the duration of mining and other
works. The technology should be improving at
that level where the public should have trust on
nuclear industry on basis of technologies and
financial performance.
Bjorn Ulsterman et al. (2007), studied in this
work on evaluation of greenhouse gas
emissions from organic and conventional
systems using carbon cycle model. The work
in this paper explain the knowledge about
carbon and nitrogen in soil-plant-animalenvironment system. In this research, soil is
used for the calculation of carbon, fossil
energy is used for the emission of carbon
dioxide, farm animals is used for the emission
of methane and again soil is used for the
emission of nitrus oxide. The specific global
warming potential is used in this work for
converting the results into carbon dioxide
equivalents.
Y.S. Mohammed, et al. (2012) has studied in
this article and presented that the effect of
human made energy generation sources will be
dangerous in future because they are emitting
the greenhouse gases in large magnitude. This
work also gives a considerable information
about energy utilization circumstances and
intimidating complicated energy context and
said that it will become worrying incident
worldwide after sometime. Some reduction
techniques byy using renewable energy and
control measures are also discussed in this
article.
2 SOURCES OF GREEN HOUSE GASES
There are various greenhouse gases are Water
vapor (H20), Carbon dioxide (CO2), Methane
(CH4), Nitrous oxide (N20), Ozone (O3),
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Chlorofluorocarbons (CFCs). There are
various sources of these greenhouse gases.
That are natural systems and human activities,
human activities are the energy production,
transformation and consumption. The fraction
of an emission left behind in the atmosphere
after a particular time is the "Airborne
Fraction" (AF). The yearly AF is the ratio of
the atmospheric rise in a given year to that
year's total emissions. The percentage
contribution of the greenhouse gases to the
greenhouse effect on earth the four major gases
are: carbon dioxide 9–26%, methane, 4–9%,
water vapour 36–70%, ozone 3–7%.
The percentages of annual greenhouse gases
are shown in fig.
Annual Green House Gases
Emissions INDUSTRIAL
TRANSPORTATION
10.3
AGRICULTURE
16.8
POWER PLANTS
11.3
14
10
3.4
21.3
12.5
WASTE DISPOSAL
LAND USE AND
BIOMASS
FOSSIL FUEL
RESIDENTIAL AND
COMMERCIAL
2.1 Impact of Green House Effect On
Environment
Global Warming
If the greenhouse gases concentration
increases then reduction in outgoing infrared
radiation occurs, thus the Earth's climate
would change this “climatic change” is called
as “global warming” of the Earth's surface and
the subordinate atmosphere as warming up.
Nevertheless, a small increase in temperature
will bring many other changes such as cloud
cover and wind patterns. Some of these
changes may be work to boost the warming.
Based
on
some
research
the
"Intergovernmental Panel on Climate Change"
in their third assessment report has forecast
that global mean surface temperature will rise
by 1.4℃ to 5.8℃ by the end of 2100. This
protrusion takes into explanation the effects of
aerosols which tend to cool the climate as well
as the delaying effects of the oceans which
have a large thermal capacity.
Sea Level Rise
If global warming occurs, sea level will go up
due to two different processes. Firstly, warmer
temperature grounds sea level to rise due to the
thermal expansion of seawater. Secondly,
water from melting glaciers and the ice of
Greenland and the Antarctica would also add
water to the ocean. It is forecasted that the
Earth's common sea level will rise by 0.09 to
0.88 m between 1990 and 2100.
Impact on Human Life
Over half of the human population lives within
100 kilometres of the sea. Most of this
population lives in urban areas that serve as
seaports. A measurable rise in sea level will
have a severe economic impact on low lying
coastal areas and islands, for examples,
increasing the beach erosion rates along
coastlines, rising sea level displacing fresh
groundwater for a substantial distance inland.
Experiments have shown that with higher
concentrations of CO2, plants can grow bigger
and faster. However, the effect of global
warming may affect the atmospheric general
circulation and thus altering the global
precipitation pattern as well as changing the
soil moisture contents over various continents.
Impact on Aquatic systems
Due increment in temperature the wetlands are
reduced so the population of marine species are
reduced. Nevertheless, the full impact on
aquatic species is not known.
Impact on Hydrological Cycle
Rise in temperature increases evaporation that
creates more rainfall. In some regions there is
a great rainfall while in few areas there is no
rainfall. So, these fluctuations may increase the
global precipitation.
3.
RENEWABLE
ENERGY
AND
RESOURCES
Renewable energy resources are scattered exist
in excess of wide geological areas than other
energy resources which are intense in few
countries. Now a day’s quick consumption of
renewable energy resources is necessary
because they are renewable. The results of a
recent review of the literature concluded that
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as greenhouse gas (GHG) emitters begin to be
held liable for damages resulting from GHG
emissions resulting in climate change, a high
value for liability mitigation would provide
powerful incentives for deployment of
renewable energy technologies. In worldwide
survey of public analysis show that most of the
civilian are in support of renewable energy
sources. More than 30 countries are using more
than 20% of their energy supply as a renewable
energy. Two nations that are Norway and
Iceland are making their full energy by using
renewable energy sources and some other
countries are preparing for renewable energy
for their energy supply.
Earlier to the growth of coal in the middle of
the 19th century almost all energy used was
renewable. Almost without a doubt the oldest
known use of renewable energy in the form of
traditional biomass to fuel fires dates from
7,90,000 years ago. Use of biomass
for hearth failed
to become
common
place till several many thousands of years
later someday between a pair of, 2,00,000 and
4,00,000 years past in all probability the
second oldest tradition of renewable energy is
harnessing the wind so as to steer ships higher
than water.
In
past
time
the
human labour, animal power, water power and
wind were the renewable resources.
Renewable energy resources may be some
natural
resources
like
that
Sun's
electromagnetic radiation, tides or heat
generation inside the Earth. Following are the
main renewable energy resources:
Solar energy the radiation of the sun is
captured in solar panels that are exposed to
sunlight. The sunlight can be changed into
electrical energy to power all the appliances in
a home. It can also be used to heat a house and
to create hot water. There are also some
drawbacks in solar energy system that they
consume some more space for their
arrangement and the collection of energy
completely depends upon whether conditions.
Wind power it is energy derived from
the movement of the wind. The most
recognizable example of wind power is the
windmill, which is using for crushing the grain.
This principle is also using in generation of
electricity using turbine that is known as wind
turbine. Wind is a very hygienic resource of
energy, but it requires large space and
occasionally noisy blades to work.
Biomass energy when the plant
material and animal excreta is burnt then there
was the emission of biomass energy. Biomass
comes from freshly livelihood organisms, not
the old materials that form fossil fuels.
Geothermal energy The Earth's
interior is extremely hot—hot enough to melt
the rock that comes out of a volcano in the form
of lava. That heat creates hot water and steam
below the Earth's surface, which can be
harnessed by digging a well. As the steam or
water rises, it can be used to run a turbine and
create electricity.
Hydropower is energy captured from
the movement of water. It is sometimes called
hydroelectric power because the water is used
to turn turbines that create electricity. The
hydropower energy is a fresh and fine source
of energy that creates about no pollution but it
may cause changes to the surrounding
atmosphere that can influence animals and
plants.
3.1 Advantages of Renewable Energy
1.
First main advantage of renewable
energy is that it is renewable it is therefore
durable and so it will never run out.
2.
Renewable energy services normally
need not as much of maintenance than
conventional power generators. Their fuel
being brought from natural and available
resources that reduces the expenditure of
action.
3.
Even more importantly, renewable
energy produces little or no waste products
such as carbon dioxide or other chemical
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pollutants, so has minimal impact on the
environment.
4.
Renewable energy projects can also
bring economic benefits to many regional
areas, as most projects are located away from
large urban centres and suburbs of the capital
cities.
3.2 Disadvantages of Renewable Energy
5.
First main drawback of renewable
energy that it is not easy to produce the energy
in bulk as great as those generated by
conventional fossil fuel generators. Because
the consumption is more than the production in
our society. For proper maintenance there
should be a perfect balance in various sources
of energy.
6.
Another difficulty in renewable energy
resources is that this energy depends on
whether conditions. For example, flowing
water is required to operate the hydro
generators and wind is required to operate the
wind turbines. The present cost of renewable
energy is more than conventional energy
generators.
7.
The production of renewable energy is
required more space and for collection it
requires the particular location that means if
we want to take more benefits of renewable
energy we have to construct a whole
arrangement of network. And these
arrangements of network require burning the
fossil fuels that ultimately emits the
greenhouse gases.
ROLE OF RENEWABLE ENERGY IN
REDUCTION OF GREEN HOUSE GASES
AND CONTROL MEASURES
1. No Damage to Environment while
Extracting
Major energy resources used for power
generation are extracted from the core of the
planet.
This
includes
oil, gas,
or
coal. large amounts of those resources square
measure extracted,
and
it wants a
lot
of exploitation of the mother Earth.
This results in increase in expenses due
to constant
drilling.
This lead
to the
discharge of hepatotoxic gases
into
the
atmosphere that becomes damaging for
nature additionally as humans. However,
on the opposite hand, the renewable-energy
sources square measure simply obtained, and
that they don't unleash any harmful gases.
2. Reduction in Carbon Emission
If we use the conventional energy resources the
carbon dioxide emission increases in the
environment. On the other hand, if we use the
renewable sources for energy the emission of
carbon dioxide drastically reduces. The
renewable energy is nearby in great quantity
only wants right technology and infrastructure.
Some researchers said that conventional power
generation resources emit nearly 40% of the
carbon dioxide. Which is destructive to the
atmosphere.
3. Helps in reducing Global Warming
The renewable-energy resources facilitate for
reducing the global warming as it reduces the
quantity of greenhouse gases emission to the
environment that is major contributing factor
to it. The renewable energy sources will help
in eliminating the emission of poisonous gases.
4. Sustaining the Renewable-Energy
Sources
It is very important to keep up the renewableenergy resources because these are
facilitating in generating the fresh and clean
energy which is very important and useful for
the environment now a day. For this, the
government
ought
to expect to the
correct infrastructure
and
technological
improvement which will facilitate them to
sustain
for longer.
Moreover,
the property can facilitate in handling several
environmental problems
regarding fuel depletion,
emission
of dioxide and alternative threatening problem
s.
5. Decreases the Adverse Environmental
Impacts
The renewable energy is a clean type of energy
on the other hand another conventional type of
resources is giving the harmful and injurious
environment. So, we should have to go for
renewable energy because by using this energy
we can keep our country green and clean.
The world is growing on daily basis more and
more so the individual requires the utilization
of the electricity at residence or industrialized
establishments. So, it is the best time to about
turn from conventional resources to the
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renewable resources feel the clean and green
environment.
8.
CONCLUSION
This research study concluded that energy
production, transformation and consumption
are the main reasons of greenhouse gases
emission and global warming that are very
harmful and adverse to human life. This study
has also shown that the energy production,
transformation and consumption are the major
source of greenhouse gas emission actually
and human actions are the minor sources. It is
clear from this work that these gases and
agents are very harmful to us so application of
renewable energy is the best option for
reducing the effects of these harmful agents to
the environment. Ultimately, it is required to
increase the uses of renewable energy
utilization to solve the problems of energy
safety, energy loss and health related issues.
The earth is enclosed by a cover of gases,
which allows the energy from the sun to reach
the earth’s surface and temperate it. The
majority of the heat is reflected back to space
but some part of gases is retained by the
atmosphere that increases the temperature of
the earth so the gases which retain the heat in
atmosphere is called as greenhouse gases and
this effect is known as greenhouse effect. So,
this increment in temperature results some
problems to environment such as global
warming, melting of ice and sea level rise etc.
By using the renewable energy like solar,
wind, biomass and hydropower etc. we can
reduce the effect of greenhouse problems and
can give the healthy and joyful environment to
the coming generation.
9.
1.
2.
REFERENCES
Pooja T. Latake, Pooja Pawar, Anil C
Ranveer, 2015, “The Greenhouse Effect
and Its Impacts on Environment”,
International Journal of Innovative
Research and Creative Technology,
IJIRCT, ISSN: 2454-5988, (2015)/
IJIRCT1201068.
Bjorn Kustermann, Maximilian Kainz,
Kurt-Jurgen
Hulsbergen,
2007,
“Modeling carbon cycles and estimation
of greenhouse gas emissions from
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organic and conventional farming
systems’’, Renewable Agriculture and
Food Systems: 23(1); 38–52, 30 july
2007.
Noam Lior, 2008, “Energy Resources
and Use: The Present Situation and
Possible Paths to The Future, Journal of
Energy, Elsevier Publication, Energy 33,
842-857,
doi:10.1016/j.energy.2007.09.009.
Joshua M. Pearce,2012, “Limitations of
Nuclear Power as a Sustainable Energy
Source”, Journal of Sustainability, ISSN
2071-1050,
4,
1173-1187;
doi:10.3390/su4061173.
Y.S. Mohammed, A.S. Mokhtar, N.
Bashir, U.U. Abdullahi, S.J. Kaku, U.
Umar, 2012, “A Synopsis on the Effects
of Anthropogenic Greenhouse Gases
Emissions from Power Generation and
Energy Consumption” , International
Journal of Scientific and Research
Publications, ISSN 2250-3153,1-7, 10,
October, 2012.
Scott Canonico, Royston Sellman, Chris
Preist, 2009 “Reducing the Greenhouse
Gas Emissions of Commercial Print with
Digital Technologies,” International
Symposium on Sustainable Systems and
Technology (ISSST),1-8.
Arman Shehabi, Ben Walker and Eric
Masanet, 2014,“The energy and
greenhouse-gas implications of internet
video streaming in the United States”,
Environ. Res, 1-11.
WWW. History of greenhouse gases,
(http://en.wikipedia.org/wiki/Greenhous
e_gas)
Greenhouse effect –Wikipedia.com.
Renewable energy – Wikipedia.com.
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Fault Ride-Through Techniques of Wind Turbine State of Art: A
Review
Manish kumawat, Aditya Prakash Dixit
Department of Electrical Engineering, Govt. Engineering College Banswara, Raj. (India)
Corresponding Author: mkumawat813@gmail.com
Abstract
Today, renewable sources for the generation of electricity is becoming more popular due to depleting
fossil fuels. Solar and wind energy is the world’s fastest growing source of renewable energy also grid
integration of wind power is growing in leaps and bounds and India is one of them. The cost of
producing one kilowatt hour of electrical energy from the wind power is the cheapest. All this has
become possible because of recent developments in electrical, mechanical, power electronics, materials
and other fields which have wide range of applications in renewable energy technology. Wind power,
at the one end is very much useful source of energy same time when it is connected to the electric grid
creates some quality issues like voltage sag, swell, harmonics etc. Wind power plants are much affected
by faults which occur in each and every power plant. In this article a comparative study has been
carried out for different fault ride-through techniques.
Keywords: Renewable Energy, Fault ride-Through Technique, Crowbar, Blade-pitch angle control,
STATCOM
1.
Introduction
The Renewable energy is a form of energy
which is obtained from naturally from tides,
wave, sunlight, wind, ocean and geothermal
heat. It is used in following important areas
such as generation of electricity, heating and
cooling of water and air, transportation,
and rural (off-grid) energy services. Renewable
energy sources exist around the world, in
discriminate to other energy sources, which are
situated in a limited number of areas. Rapid
expand and utilization of renewable energy
may reduce the rate of climate change and
affect the world in economic measure.
1.1 Renewable energy in India
India is a vast country. Its energy requirement is
increasing day by day and depleting coal make
to switch towards renewables. Based
on Renewable Energy Policy Network of 21
century (REN21's) 2017 report, renewables
contributed 17.7% to total Indian energy
consumption. Renewable sources for electricity
are targeted to increase heavily by 2022 this
includes more than doubling of large wind
power capacity. These large targets, if achieved
timely, would place India amongst the world
leaders in renewable energy sector. Overall
installed capacity of India is 329.4 GW and
renewables contribute 57.472 GW as of 14 June
2017. Contribution of wind and solar is nearly
61% and 19% respectively. MNRE has sets its
targets to produce renewable electricity from 43
GW in April 2016 to 175 GW by 2022. This
includes 100 GW from solar power, 60 GW
from wind power. These ambitious targets
would make India one of the leading green
energy producers and surpassing many
developed countries in the world. Wind power
generation capacity in India has significantly
increased in recent years making total installed
capacity of 32.72 GW (October 2017). This is
the fourth largest installed wind power capacity
in the world. Due to increment of wind power
the tariff of wind power has dipped a record
low of ₹2.64 (4.1¢ US) per kWh (without any
subsidies) during the auctions for wind power
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projects in October 2017. Before that the tariff
was Rs.3.42/kWh in August 2017. Following
tables shows the Fuel wise Generation Installed
Capacity in India and Installed capacity of
renewable energy source in India.
Table 1.1 Fuel wise Generation Installed
Capacity in India
Fuel
Installed
(MW)
THERMAL
Coal
Gas
Diesel
HYDRO
NUCLEAR
RES
TOTAL
219,490
193,467
25,185
838
44,653
6,780
58,303
329,226
Capacity % Share
Total
in
66.7%
58.8%
7.6%
0.3%
13.6%
2.1%
17.7%
National
Power
Training
Institute
(N.R.)Badarpur, New Delhi -110044)
Table 1.2 Installed capacity of renewable
energy source (31 August 2017)
Energy source
Power(GW)
Percentage
Wind energy
32GW
56%
Solar energy
13GW
22%
Biomass energy
8GW
14%
Small hydro energy
4GW
8%
National Power Training Institute (N.R.)
Badarpur, New Delhi -110044)
1.2 Issues Associated with Wind Energy
The wind penetration levels in India has
increased dramatically in the recent years. This
increase, affect the performance of the power
system due to its integration and operation. A
moderate share does not create any problem.
Increasing capacity may create many problems
therefore new regulations for grid connection of
WPPs become necessary for stability of power
system. These new regulation creates issues
which are: 1) Interface issue and 2) Operational
issue. Interface issues are short circuit power
control, active and reactive power control and
voltage control. The operational issues are
Power system stability, frequency control, short
and long term balancing, impact on
transmission and distribution and economic
dispatch. Power system stability affects by the
faults occurring in the system and seeks more
attention. Different faults occurring in power
system also affects grid stability where the
penetration of wind power is large. Hence
transmission and distribution operators decided
to form new grid codes addressing these issues.
Thus, it was required to analyze fault ride
through behavior of DFIG wind turbine under
the influence of new grid code. Modern largescale wind turbines, typically 1 MW and larger,
are normally required to include systems that
allow them to operate through such an event,
and thereby “ride through” the voltage dip.
Depending on the application the device may,
during and after the dip, be required to:
Disconnected temporarily from the grid and
but reconnect and continue operation after
the dip, stay disconnected until manually
reconnected
stay operational and not disconnect from the
grid and support the grid with reactive power
(Fault Ride-Through)
2. Fault ride through
Fault ride through (FRT) is the capability of
WT generators to stay connected in the network
for short periods of lower voltage (voltage dip).
It is needed at distribution level to prevent a
short circuit which causes loss of generation.
Some critical loads such as computer systems
and industrial processes are handled by
an uninterruptible power supply (UPS) or
capacitor bank to supply make-up power during
interruption of supply in a similar manner.
2.1 Fault Ride-Through Requirement of
Wind Turbine Systems
Expanding wind power creates some new
problems to power system. The power system
with large scale wind power will involve
problems in steady state operation and in
contingency condition. FRT keep the WTs to
stay connected to grid during faults so that
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stability to the power transmission system is
maintained. The most common fault in the
power system is voltage drop and its lowest
depth can be zero. The stator of DFIG is
directly connected to the grid, while its threephase rotor windings are coupled to the grid
through a back-to-back converter. Very high
rotor current may lead to the damage of rotor
side converter and the DC bus over-voltage.
During the fault, a large fault current flows
through the stator of DFIG because it is directly
connected to the grid. Since the rotor and stator
are magnetically coupled and the flux is
conservative this disturbance must affect the
rotor of DFIG making the rotor current very
high and an overcurrent may flow through the
rotor side converter. Owing to this WTs must
have capability to support voltage by providing
reactive power to the grid and this is done
riding-through the fault. Following figure
shows the voltage supporting capability of
WTs.
capability to maintain the reactive power
balance and the power factor in the desired
range.
3.
Strategies
FRT approaches can be divided into two main
categories:
1.
Passive Methods these methods use
additional equipment: such as crowbar
methods, energy capacitor system (ECS) and
energy storage system (ESS), blade pitch angle
control.
2.
Active Methods These methods use
appropriate converter control.
1. Passive methods
A) Blade pitch angle control: It is one of the
most widely used techniques to regulate the
output power of a wind turbine. This method is
based on the variation in the input power to the
turbine as the pitch angle of the blades is
changed. Pitch angle of blade is varied by
hydraulic actuators.
B) Crowbar methods: This is the classical
method to fulfill FRT requirements. It has
ability to protect the generator and the converter
as well during the faults. Dangerous effects of
fault are minimized by crowbar protections
systems. Crowbar avoid the disconnection of
the doubly fed induction wind generators from
the network during faults.
Fig 1.1 variation of voltage in FRT
(http://energyprofessionalsymposium.com/img/
1237/image023_2.jpg
New grid codes ensures that during FRT
following conditions must meet. During a
voltage drop, turbines remain connected for
specific time duration before being allowed to
disconnect. Wind power plants must regulate
their active power output to ensure a stable
frequency in the system and reactive power
Fig 2.1 Crowbar [9]
Faults at terminal of DFIG induced the high
current and increased the DC-link voltage of the
converter, to protect from this severe condition
crowbar
protection
system
is
used.
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Conventional crowbar, series crowbar and a
new protection method named the outer
crowbar are main types of crowbar system.
In conventional crowbar technique, when a
short circuit occurred the RSC is disabled and
bypassed, at the same time external resistors are
coupled via the slip rings of the rotor windings
in place of the converter.
The series crowbar, three resistors which are
parallel with bidirectional static switches are
connected in series with stator winding. During
short circuit at the DFIG terminals these
switches are triggered otherwise switches are
not triggered.
Outer crowbar is quite similar to series crowbar
but difference in series crowbar and series outer
crowbar is that the outer crow bar is connected
in series with the DFIG instead of the stator
winding.
C) Energy capacitor system: This method is
similar to some extent to crowbar
configuration, except that this method protects
the converter from overvoltage and can
dissipate energy without effecting the rotor
currents.
Fig 2.2 Energy capacitor (https://ars.elscdn.com/content/image/1-s2.0S0378779613002174 gr1.jpg)
D) Energy storage system: This method
controls the generator during the fault. The
battery stores energy in the electrochemical
form, and is the most widely used for energy
storage in a variety of application.
Fig 2.3 Energy storage (https://ars.elscdn.com/content/image/1-s2.0S0960148116302981-gr15.jpg)
2. Active Methods
It is a combination between hardware
modifications (e.g., crowbar) and control
strategies.
A feed-forward transient current control scheme
is used for the rotor side converter (RSC) of a
DFIG with crowbar protection. Another method
uses a parallel grid side rectifier (PGSR) with a
series grid side converter (SGSC). All these
methods require additional devices which leads
to extra costs and increases system complexity.
So, it would be better to eliminate these
devices. With these considerations, the
implementation of classical flux-oriented vector
control techniques (PI controllers) has been
proven to work well to fulfill the grid code
requirements. But, this kind of control could be
easily saturated when dealing with substantial
sag and it is sensitive to the generator
parameters and other phenomena such as
disturbances and unmodeled dynamics. These
above classical control techniques suffers from
the drawback that is their linear nature due to
which robustness is lacking.
A robust nonlinear controller based on the
sliding mode, an LVRT scheme for a PMSGbased WT based on the feedback linearization
theory and a susceptance control strategy are
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some non- linear control strategies are also
proposed for FRT of wind turbines.
3. New approaches
STATCOM and DVR are the new devices to
provide FRT of WTs.
Static synchronous compensator (STATCOM)
is a Flexible AC Transmission Systems
(FACTS) device. It is a power electronic based
synchronous var compensator that generates
three-phase reactive power in synchronism with
the transmission line voltage. It is connected to
it by a coupling transformer. STATCOM
consist of a three-phase inverter using Gate
Turn-off Thyristors. It acts as a sink or a source
of reactive power (inductor/capacitor). By
varying the amplitude of the converter voltage
with respect to the system bus voltage,
STATCOM can continuously exchange power
through the flow of a controlled current. The
power exchange between STATCOM and rest
of the system is purely reactive although an
insignificant amount of active power is supplied
by the grid to compensate for converter losses.
This reactive power support enables the
STATCOM improve the voltage profile of the
system and reduce voltage fluctuation in event
of grid disturbance.
Dynamic Voltage Restorer (DVR) is a series
connected device, which corrects the voltage
dip and restore the load voltage in case of a
voltage dip. Basic DVR topology is illustrated
in Fig 3.1. Dynamic Voltage Restorer (DVR) is
applied to compensate for voltage sags and
swells and expected to respond fast (less than
1/4 cycle) and thus employs PWM converters
using IGBT devices.
Figure 3.1 Basic DVR Topology
4. Comparison
Faults are the severe problem faced by wind
turbines connected to grid. Due to fault in the
system power is lost so fault ride-through
provides the alternative power to distribution
network. So many FRT techniques are
proposed for this. All the methods of FRT have
some advantages and disadvantages associated
with them. Passive methods are easy to
implement, cost effective, have best
controllability of active and reactive power also
improve voltage profile. They also suffers some
disadvantages like large response time and have
reduced peak generating capacity, also absorbs
large amount of reactive power from the grid
this will degrade the grid voltage. In some
methods additional energy storing elements are
required which further increases the cost of the
system. Due to additional cost and complexity
in passive methods, active methods using PI
controller are proposed. These methods
saturated easily when they deal with sags. Some
linear controllers are also there but they are not
robust. Besides this some new techniques are
under development and testing. These are
STSTCOM and DVR method. They provide
active and reactive power to the system during
fault when it is required during faults.
5.
Conclusion
LVRT is found to be the biggest challenge
facing by wind turbine farms; in particular
those using DFIGs. This type of generator is
very sensitive to grid disturbance, in particular
voltage sags. To overcome this sensitivity,
several FRT techniques have been proposed.
These strategies have been examined and
advantages and disadvantages of each one have
been discussed. The use of additional hardware
can be avoided if the rotor-side converter is
able to counter the grid disturbance effects.
Therefore, particular attention has been drawn
to nonlinear control strategies. Some new
techniques are also developed in recent years.
FRT techniques are very costly and industries
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doesn’t disclose their researches due to
competitive
market.
Therefore,
future
researches should be focused on the
development of DFIG robust and cheaper
strategies for the solution of FRT problem.
Reference
1. Marwa Ezzat, Mohamed Benbouzid, Sm
Muyeen, Lennart Harnefors. Low-Voltage
Ride-Through Techniques for DFIG-Based
Wind Turbines: State-of-the-Art Review and
Future Trends. IEEE IECON 2013, Nov 2013,
Vienne, Austria. pp.7681-7686, 2013.
2. Xinyan Zhang1, Xuan Cao2, Weiqing
Wang1, Chao Yun1 Fault Ride-Through Study
of Wind Turbines Journal of Power and Energy
Engineering, 2013, 1, 25-29
3. Supercapacitor energy storage system for
fault ride-through of a DFIG wind generation
system A.H.M.A. Rahim a,⇑, E.P. Nowicki b a
Department of Electrical Engineering, King
Fahd University of Petroleum & Minerals,
Dhahran, Saudi Arabiab Department of
Electrica & Computer Engineering, University
of Calgary, Calgary, AB,Canada
4. Ms.Ch.laxmi, Ms.K.Sree Latha, 3Dr.Himani
1Asst.prof(EEE)
GNITC,Hyderabad
2Assoc.Prof(EEE) GNITC, Hyderabad 3Prof &
HOD(EEE) Aurora’s Engg ,Bhongir
Improving the low voltage ride through
capability of wind generator system using
crowbar and Battery Energy storage system.
International Journal of Engineering Science
Invention ISSN (Online): 2319 – 6734, ISSN
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5. Supercapacitor energy storage based-UPQC
to enhance ride-through capability of wind
turbine
generators
Gangatharan
SIVASANKAR, Velu SURESH KUMAR
Department of Electrical and Electronics
Engineering,
Thiagarajar
College
of
Engineering, Madurai, India, Turk J Elec Eng
& Comp Sci (2015) 23: 1867 { 1881
6. Montazeri, Miad Mohaghegh, "Improved
Low Voltage Ride Through Capability of Wind
Farm using STATCOM" (2011). Theses and
dissertations. Paper 1407.
7.C. Jauch, P. Sorensen, I. Norheim and C.
Rasmussen, “Simulation of the Impact of Wind
Power on the Tran- sient Fault Behavior of the
Nordic Power System,” Elec- tric Power
System Research, Vol. 77, 2007, pp. 135-144.
8.S. J. Hu, J. L. Li and H. H. Xu, “Analysis on
the Low- Voltage-Ride-Through Capability of
Direct-Drive Perma- nent Magnetic Generator
Wind Turbines,” Automation of Electric Power
Systems, Vol. 31, No. 17, 2007, pp. 73-77.
9.https://www.researchgate.net/profile/Sadegh_
Ghani_Varzaneh/publication/281627313/figure/
fig1/AS:287010901250058@1445440139828/F
igure-1-Schematic-diagram-for-DFIGaccompanied-with-conventional-crowbarprotection.png.
10. Meegahapola LG, Littler T, Flynn D.
Decoupled-DFIG fault ride-throughstrategy for
enhanced stability performance during grid
faults. IEEE Trans Sustain Energy 2010;1:152–
62.
11. Ahsanul Alam M, Rahim AHMA, Abido
MA. Supercapacitor based energy storage
system for effective eault ride through of wind
generation system. In:IEEE international
symposium on industrial electronics (ISIE2010), Bari, Italy July, 2010.
12. X. Dawei, R. Li, P. J. Tavner, and S. Yang,
"Control of a doubly fed induction generator in
a wind turbine during grid fault ride-through,"
IEEE Transactions on Energy Conversion, vol.
21, pp. 652-662, 2006.
13. E. Koutroulis, D. Kolokotsa, and G.
Stravrakakis,"Optimal design and economic
evaluation of a batteryenergy storage system for
the maximization of the energygenerated by
wind farms in isolated electric grids,"
WindEngineering, vol. 33, pp. 55-81, 2009.
14. V. Akhmatov, “Analysis of dynamic
behavior of electric power system with large
amount of wind turbine”, Ph.D. thesis, Orsted
DTU, pp. 26–28,30, 31, 2003.
15. S. M. Muyeen, R. Takahashi, T. Murata,
and J. Tamura, “Integration of an energy
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capacitor system with a variablespeed wind
generator,” IEEE Trans. Energy Convers., vol.
24, no. 3, pp. 740-749, Sep. 2009.
16. K. H. Kim, Y. C. Jeung, D. C. Lee, and H.
G. Kim, “LVRT scheme of PMSG wind power
systems based on feedback linearization,” IEEE
Trans. Power Electron., vol. 27, no. 5, pp.
2376-2384, May 2012.
17. D. W. Xiang, S. C. Yang and L. Ran,
“Magnet Excitation Control Strategy of DFIG
on Grid Operation during Power System
Symmetric Fault,” Proceedings of the CSEE,
Vol. 26, No. 3, 2006, pp. 164-169.
18. D. Campos-Gaona, E. Moreno-Goytia and
O.
Anaya-Lara,
“Fault
Ride-Through
Improvement of DFIG-WT by Inte- grating a
Two-Degrees-of-Freedom Internal Model Control,” IEEE Transactions on Industrial
Electronics, Vol. 60, No. 3, 2013, pp. 11331145.
19. F. Díaz-González, A. Sumper, O. GomisBellmunt and R. Villafáfila- Robles, “A review
of energy storage technologies for wind power
applications,” Renewable and Sustainable
Energy Reviews, vol. 16, n°4,pp. 2154-2171,
May 2012.
20. D. Ramirez, S. Martinez, C. Carrero and
C.A. Platero, “Improvements in the grid
connection of renewable generators with full
power converters,”Renewable Energy, vol. 43,
pp. 90-100, July 2012.
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Numerical solution to Natural convection in Triangular enclosures and
its application for double dome solar water distillation systems
Nagesh Babu Balama, Akhilesh Guptab, Ashok Kumara, B.M Sumana
a
CSIR-Central Building Research Institute, Roorkee, India
b
Indian Institute of Technology, Roorkee, India
Abstract:
Natural convection flow is numerically estimated in triangular domain using finite difference method.
Natural convection flow in triangular domain enclosures is a common phenomenon observed in a variety
of applications such as double dome type solar water distillation units, building roof top cross-section
(attic space), solar collectors and in many other engineering applications. Convection flow is analyzed
by varying the Rayleigh number (Ra) from 103 to 106 and the aspect ratio from 0.2 to 1.0 with bottom
surface heated and inclined surfaces cooled simultaneously. The fluid inside the domain is air having
Prandtl no (Pr) = 0.7. The results are presented in stream line and temperature contours. Bipartisan,
counter rotating triangular and symmetric stream line contours are observed within the domain for lower
values of Ra. As ‘Ra’ value is increased the stream line contours exhibit unsymmetrical behavior with
one major contour and counter rotating minor contours. The present study provides more physical insight
into the natural convection in triangular domain applications and also provide a mechanism to control
the heat transfer by varying aspect ratio at the design stage.
Keywords: Natural convection, Finite Difference method, Vorticity, Streamfunction, Triangular
Domain.
Nomenclature:
Ar Aspect Ratio (H/L)
β Thermal expansion coefficienct
Gr Grashoff number
ε Numerical tolerance limit
H
Height of enclosure
θ Non dimensional temperature
L
Length of enclosure
ν Kinematic viscosity
n
Time step
ρ density
Pr
Prandtl number
τ Non dimensional time
Ra Rayeligh number
ψ Stream function
t
time
ω vorticity
T
Temperature
γ Angle of inclination
Subscripts
𝑢⃗ Velocity vector
u,v Vel. components in x & y directions
h hot
x,y Transverse and normal coordinates
c cold
α
Thermal diffusivity
I,j X and Y coordinate indices
1.
Introduction:
Natural convection in triangular enclosures is a
very common phenomena observed in variety of
applications such as double dome type solar
water distillation units, building roof top crosssection (attic space), solar collectors and in
many other engineering applications. A
comprehensive review of natural convection in
triangular enclosures is carried out by kamiyo et
al [1] and das et al [2] and Saha et al[3]. Natural
convection in isosceles triangular domain is
studied by many researchers due to its variety of
applications. Holtzman et al [4] has carried out
experimental and numerical laminar natural
convection studies in isosceles triangular
enclosures with a heated horizontal base and
cooled upper walls. The problem is examined
over aspect ratios ranging from 0.2 to 1.0 and
Grashof number (Gr) from 103 to 105.
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Pitchfork bifurcation is observed at critical Gr
above which the symmetric solutions are
unstable to finite perturbations and asymmetric
solutions are instead obtained. Basak et al. [5]
used finite element method to simulate the
natural convection in isosceles triangular
enclosures due to uniform and non-uniform
heating at the side walls. The numerical solution
of the problem is presented for various Rayleigh
numbers (Ra), (103 < Ra < 106) and Prandtl
numbers (Pr), (0:026 < Pr < 1000). It has been
found that at small Prandtl numbers, geometry
does not have much influence on flow structure
while at Pr = 1000, the stream function contours
are nearly triangular showing that geometry has
considerable effect on the flow pattern. In
addition, the presence of multiple circulations
are observed for small Pr = 0.026 which causes
wavy distribution of local Nusselt number. It is
observed that non-uniform heating produces
greater heat transfer rates at the center of the
walls than the uniform heating; however,
average Nusselt numbers show overall lower
heat transfer rates for the non-uniform heating
case. Taher et al[6] used Lattice Boltzamann
method (LBM) for simulating similar problem
and studied the effect of varying the Ra and
Aspect ratio. Saha et al [7] has studied the
Natural convection in a triangular enclosure
heated from below and non-uniformly cooled
from top. The numerical simulations of the
unsteady flows over a range of Rayleigh
numbers and aspect ratios are carried out using
Finite Volume Method. Since the upper inclined
surfaces are linearly cooled and the bottom
surface is heated, the flow is potentially
unstable. It is revealed from the numerical
simulations that the transient flow development
in the enclosure can be classified into three
distinct stages; an early stage, a transitional
stage, and a steady stage. The flow inside the
enclosure depends significantly on the
governing parameters, Rayleigh number and
aspect ratio. The effect of Rayleigh number and
aspect ratio on the flow development and heat
transfer rate are discussed. The key finding for
this study is to analyze the pitchfork bifurcation
of the flow about the geometric center line. The
overall studies are found to be in good agreement
and have been able to consistently predict the
natural convection flow in triangular domain.
Similar studies were conducted for non-isosceles
and inclined triangular domains. Mahmoudi et
al. [8] conducted Numerical Study of Natural
Convection in an right-angled triangular
enclosures for Different Thermal Boundary
Conditions using Lattice Boltzmann method.
Numerical results are obtained for a wide range
of parameters: the Rayleigh number spanning
the range (103 - 106) and the inclination angle
varying in the intervals (0° to 120°) and (0° to
360°) for two cases adiabatic vertical walls and
inclined isothermal walls. It is observed that
inclination angle can be used as a relevant
parameter to control heat transfer in right-angled
triangular enclosures.
Solar distillation in double dome and single
dome structures are well studied using double
diffusive convection in triangular enclosures.
Omri et al [9] has studied the Natural convection
effects in solar stills. The aim of the study is to
examine the thermal exchange by natural
convection and effects of buoyancy forces on
flow structure. The study provides useful
informations on the flow structure sensitivity to
the governing parameters, the Rayleigh number
and the tilt angle, on the thermal exchange. In a
basin still receiving a uniform heat flux, the
results show that the bottom is not isotherm and
the flow structure is sensitive to the cover tilt
angle. Many recirculation zones can occur in the
core of the cavity and the heat transfer is
dependent on the flow structure. The results of
this study can provide information for the
enhancement of the design of the energy systems
such as solar water distillers and air conditioning
systems. Rahman et al [10] has studied the
Double-diffusive natural convection in a
triangular solar collector. Effects of the thermal
Rayleigh number and buoyancy ratio are
presented
by
streamlines,
isotherms,
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isoconcentration as well as local and mean heat
and mass transfer rates for the aforesaid
parameters. Effects of the thermal Rayleigh
number and buoyancy ratio are presented by
streamlines, isotherms, isoconcentration as well
as local and mean heat and mass transfer rates
for the aforesaid parameters.
Varol et al. [11] has conducted study on Natural
convection in triangular enclosures with
protruding isothermal heater. Governing
parameters, which are effective on flow field and
temperature distribution, are; Rayleigh number,
aspect ratio of triangle enclosure, dimensionless
height of heater, dimensionless location of
heater and dimensionless width of heater.
Streamlines, isotherms, velocity profiles, local
and mean Nusselt numbers are presented. It is
found that all parameters related with
geometrical dimensions of the heater are
effective on temperature distribution, flow field
and heat transfer.
In the present study, Convection flow is
analyzed by varying the Rayleigh number (Ra)
from 103 to 106 and the aspect ratio (base
length/height) from 0.2 to 1.0 with bottom
surface heated and inclined surfaces cooled
simultaneously. The fluid inside the domain is
air having Prandtl no (Pr) = 0.7. The results are
presented in stream line and temperature
contours.
2. Problem Formulation
Figure1: The triangular domain model
Consider a 2D triangular domain of base length
‘2l’ and height ‘H’ as shown in Fig. 1. The cavity
is filled with air and its bottom and inclined
walls are maintained at ‘θh’ and ‘θc’,
respectively. Boundary conditions for a
triangular enclosure is shown in figure [1].
A 2D Laminar Natural Convection flow is
assumed inside the cavity. Boussinesq
approximation is assumed for the gravity term in
the momentum equation. The flow is governed
by the following set of equations.
Conservation of Mass
𝜕𝑢 𝜕𝑣
+
=0
𝜕𝑥 𝜕𝑦
Conservation of X-directional Momentum with
Boussinesq approximation
𝜕𝑢
𝜕𝑢
𝜕𝑢
+𝑢
+𝑣
𝜕𝑡
𝜕𝑥
𝜕𝑦
1 𝜕𝑝
𝜕 𝑢 𝜕 𝑢
= −
+𝜐
+
𝜌 𝜕𝑥
𝜕𝑥
𝜕𝑦
− 𝑔𝛽 (𝑇 − 𝑇 )𝑠𝑖𝑛𝛾
Conservation of Y-directional Momentum with
Boussinesq approximation
𝜕𝑣
𝜕𝑣
𝜕𝑣
+𝑢
+𝑣
𝜕𝑡
𝜕𝑥
𝜕𝑦
1 𝜕𝑝
𝜕 𝑣 𝜕 𝑣
= −
+𝜐
+
𝜌 𝜕𝑦
𝜕𝑥
𝜕𝑦
+ 𝑔𝛽 (𝑇 − 𝑇 )𝑐𝑜𝑠𝛾
Conservation of Energy
𝜕𝑇
𝜕𝑇
𝜕𝑇
𝜕 𝑇 𝜕 𝑇
+𝑢
+𝑣
= 𝛼
+
𝜕𝑡
𝜕𝑥
𝜕𝑦
𝜕𝑥
𝜕𝑦
Average Nusselt Number
1
𝜕𝑇
𝑁𝑢 = −
𝑑𝑦
𝐿
𝜕𝑥
Grashoff Number: Gr = Ra X Pr
Boundary conditions for a triangular domain are
as follows
𝑥 = 𝑥, 𝑦 = 0: 𝑢 = 0, 𝑣 = 0, 𝑇 = 𝑇
𝑥 = 𝑥, 𝑦 = 𝑥: 𝑢 = 0, 𝑣 = 0, 𝑇 = 𝑇 ∀ (𝑥 ≤ 𝑙)
𝑥 = 𝑥, 𝑦 = (2𝑙 − 𝑥), 𝑢 = 0, 𝑣 = 0, 𝑇 =
𝑇 ∀( 𝑥 > 𝑙)
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2.
Numerical Method
The governing equations are solved in a 2D
triangular domain. Vorticity-Stream function
formulation is used for solving the Governing
equations. Obtained Partial differential
equations for Stream function, vorticity and
Temperature are converted to Algebraic
equations using Finite difference method.
Staircase approximation is used to solve the
finite difference method applied to nonrectangular geometry. 1st order Upwind scheme
is used for discretization of convective terms.
2nd order Central difference scheme is used for
discretization of diffusion terms. 2nd Order
Alternate Direction Implicit (ADI) scheme is
used to discretize the transient term. The
obtained coefficient matrices are in implicit line
Tri-diagonal form and are solved using Thomas
algorithm. The numerical computations are
carried out for 154X77 grid nodal points for a
time step of 10-4. The convergence criteria
required that the absolute difference between the
current and previous iterations for all of the
dependent variable be less than 10-5. Grid
Independence test is carried out and found
154X77 grid density gives satisfactory
performance for the present study. The average
Nusselt number is calculated at the bottom
surface.
4.Results
The results obtained for triangular domain are
compared with Holtzman et al.[4]. for the
Average Convective Nusselt number parameter.
This parameter is defined as given below. Table
[1] shows the comparision of Nuc for various
Aspect ratios in the range of 0.2 to 1.0. and for
Grashoff Number in the range of 103 to 105 .
Figure [2] shows the comparision of local
convective Nusselt number ( Nuc ) along the
Symmetric plane of Isosceles triangular domain
for Ar = 0.5, Gr = 105
Average Convective Nusselt Number Nuc :
1 2 Ar
Nuc ( X )dX
2 Ar 0
where Convective Nusselt Number is the ratio of
Nusselt number at given Gr to Nusselt number
evaluated for corresponding conduction solution
I.e Gr = 0 given by
Nuc Gr
Nuc Gr and
Nu c
;
Nuc Gr 0
Y Y 0
H
Ar for triangular domain shown in figure []
L
Nu c
Grid Independence study:
The governing equations are solved in a 2D
triangular domain. The numerical computations
are carried out for 154X77 grid nodal points for
a time step of 10-4. The convergence criteria
required that the absolute difference between the
current and previous iterations for all of the
dependent variable be less than 10-5. Grid
Independence test is carried out for various grid
sizes from 101X51, 154X77, 201X101 and
found that 154X77 grid density gives
satisfactory performance for the present study.
Table1 : Comparision of Average Convective
Nusselt Number, with holtzman et al.:
Aspect Gr = Gr = Gr =
Ratio
103
104
105
Holtzman 1.0
1.0
1.07 1.80
et al.
Present
0.996 1.08 1.85
Study
Holtzman 0.5
1.0
1.20 2.19
et al.
Present
0.99
1.20 2.20
Study
Holtzman 0.2
1.0
1.28 2.48
et al.
Present
0.998 1.29 2.45
Study
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Figure 3: Natural convection flow Isotherms
with Aspect ratio:1.0, Ra = 103
Figure 4: Natural convection flow Streamlines
with Aspect ratio:1.0, Ra = 103
Figure 2 : Comparision of local convective
Nusselt number with Holtzman et al.
The
non-dimensional
streamline
and
temperature contours are shown in the following
figures [3 - 10] by varying the Rayleigh number
from Ra = 103 to 105 . The effect of changing the
angle of inclination of inclined walls is observed
in figure [9-10] for Ra = 106 and inclination
angle of inclined walls = 30°.
Figure 5: Natural convection flow Isotherms
with Aspect ratio:1.0, Ra = 104
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Figure 6: Natural convection flow Streamlines
with Aspect ratio:1.0, Ra = 104
Figure 9: Isotherms for Ra = 106 and angle of
inclination = 30°.
Figure 7: Natural convection flow Isotherms
with Aspect ratio:1.0, Ra = 105
Figure 10: Streamline and Isotherms for Ra =
106 and angle of inclination = 30°.
Figure 8: Natural convection flow Streamlines
with Aspect ratio:1.0, Ra = 105
Conclusions:
This paper presents a method for solving viscous
incompressible Navier-stokes equations in
vorticity stream-function formulation and its
application to natural convection flow in
triangular domain.
Convection flow is analyzed by varying the
Rayleigh number (Ra) from 103 to 106 and the
aspect ratio from 0.2 to 1.0 with bottom surface
heated
and
inclined
surfaces
cooled
simultaneously.
Such
configuration
is
commonly encountered in solar water
distillation systems of double dome type.
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The results are presented in stream line and
temperature contours. At low temperature
difference between bottom wall and inclined
walls the heat raises at the symmetric plane at
center of triangular domain and cools near the
inclined walls and thus completing a rotating
contours which are symmetric in nature.
Bipartisan, counter rotating triangular and
symmetric stream line contours are observed
within the domain for lower values of Ra. As
‘Ra’ value is increased the stream line contours
exhibit unsymmetrical behavior with one major
contour and counter rotating minor contours.
5.
6.
7.
The developed method estimates the Natural
convection flow behaviour in triangular domain.
The present study can be applied for optimizing
the design of Solar water distillation systems.
8.
References:
1.
O.M. Kamiyo, D. Angeli, G.S. Barozzi,
M.W. Collins, V.O.S. Olunloyo, S.O.
Talabi,A comprehensive review of natural
convection in triangular enclosures, Appl.
Mech. Rev. 63 (2010) 06080.
2.
D. Das et al., Studies on natural convection
within enclosures of various (non-square)
shapes – A review, Int. J. Heat Mass
Transfer
(2016),
http://dx.doi.org/10.1016/j.ijheatmasstran
sfer.2016.08.034
3.
S.C. Saha, M.M.K. Khan, A review of
natural convection and heat transfer in
attic-shaped space, Energy Build. 43
(2011) 2564–2571.
4.
G.A. Holtzman, R.W. Hill, K.S. Ball,
Laminar natural convection in isosceles
triangular enclosures heated from bellow
and symmetrically cooled from above,
9.
10.
11.
Journal of Heat Transfer 122 (2000) 485–
491.
T. Basak, S. Roy, Ch. Thirumalesha, Finite
element analysis of natural convection in a
triangular enclosure: effects of various
thermal boundary conditions, Chemical
Engineering Science 62 (2007) 2623–
2640.
M. A. Taher, Y. W. Lee, and H. D. Kim,
LBM Simulation on Natural Convection
Flow in a Triangular Enclosure of Green
House under Winter Day Conditions,
Journal of Engineering Thermophysics,
2016, Vol. 25, No. 3, pp. 411–423
Suvash C. Saha , Y.T. Gu, “Natural
convection in a triangular enclosure heated
from below and non-uniformly cooled
from top”, International Journal of Heat
and Mass Transfer 80 (2015) 529–538
Ahmed
Mahmoudi,
Imen
Mejri,
Mohamed Ammar Abbassi, and Ahmed
Omri, “Numerical Study of Natural
Convection in an Inclined Triangular
Cavity for Different Thermal Boundary
Conditions: Application of the Lattice
Boltzmann Method”, FDMP, vol.9, no.4,
pp.353-388, 2013
Ahmed Omri, Jamel Orfi, Sassi Ben
Nasrallah, “Natural convection effects in
solar stills”, Desalination 183 (2005) 173–
178
M.M. Rahman , Hakan F. Öztop A.
Ahsan, M.A. Kalam, Y. Varol, “Doublediffusive natural convection in a triangular
solar
collector”,
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convection in triangular enclosures with
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Concept Paper
on
Solar Parks to Ramp up Solar Projects in the Country, Issues and
Challenges: Contribution towards Climate Change
Radhey Shyam Meena1, Swati Agariya2, Prof. D. K. Palwaliya3,
Dr. Shivlal4, Dr. Nitin Gupta5, A. S. Parira6 , S K Gupta7
1,6,7Ministry of New & Renewable Energy, New Delhi, India 110003
2National Institute of Solar Energy, Gurugram, India 122005
3,4Government Engineering College Banswara, India 327001
5Malaviya National Institute of Technology, Jaipur, India 302017
Abstract
The objective of this paper is to review the basic concepts of solar parks and its new era of
development of solar projects in India. The paper describes the most recent approach for development
of solar projects in the form of a solar park with growth oriented and easily acceptable facilities to
all. Considering the declining prices of solar power vis-a-vis other source of costlier power, leading
to growth in solar sector by which it has become more affordable to Solar Project Developers (SPDs)
and Distribution Companies (DISCOMs). In solar parks an increased trend in participation in bidding,
as they foresee opportunities in solar business with reasonable return on investment. Further, the
increased scalability, assured off-take, guaranteed payment, risk free and preserving grid connectivity
also created an environment of profitable business. With a strong commitment to increase the
renewable sources-based energy capacity to 175 GW by 2022, India has a target to install 100 GW
of solar energy capacity out of which 40 GW would be the share of Solar Parks.
The another approach in this chapter is to evaluate the determined policy in India on large scale ultramega solar projects or solar parks which designed as a package deal, enabling project development
time lines to be streamlined by allowing different government as well as private agencies to undertake
land acquisition and seek necessary permits, and providing a dedicated common infrastructure in the
form of developed land, water availability and access roads, and power transmission systems for
setting up solar power generation plants inside the solar park.
Key words: Solar Parks, Renewable Energy in India, National Solar Mission, Solar Development
17) as Phase-II and the 13th Plan (2017-22) as
1. Introduction
Phase-II. Policy framework under Mission is to
National Solar Mission (NSM) is a major
create the necessary environment to attract
initiative by Government of India, to promote
industry and project developers to invest in
ecologically
sustainable
growth
and
research, domestic manufacturing and
addressing energy security challenge. The
development of solar power generation and
NSM is one of the eight missions of National
thus create the critical mass for a domestic
Action Plan on Climate Change (NAPCC).
solar industry.
Recognizing the potential of solar energy to
The mission National Solar Mission (NSM)
contribute to energy security of the country,
under the brand name “Solar India” set an
the Government of India launched NSM on the
target of adding 20 GW of Grid connected and
11th January, 2010. The objective of the NSM
2 GW of Off-grid capacity by 2022.
is to establish India as a global leader in solar
India, in its Intended Nationally Determined
energy, by creating the policy conditions for its
Contributions (INDC), announced to increase
diffusion across the country as quickly as
share of installed electric power capacity from
possible. Implementation of the Mission is
non-fossil-fuel-based energy resources by
envisaged to adopt a 3-phase approach,
2030 to 40% and to reduce the emission
spanning the period of the 11th Plan and first
intensity of its GDP from 33 to 35% by 2030.
th
year of the 12 Plan (up to 2012-13) as PhaseIn consideration of above, the Government of
I, the remaining 4 years of the 12th Plan (2013India in June 2015 scaled up the target for
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15 to 2016-17 as on 31.03.2017), as compared
to 11,746 MW installations during preceding
three years (2011-12 to 2013-14).
40000.00
32746.87
30000.00
20000.00
15747.81
8181.70
4399.35
863.92 114.08
10000.00
0.00
1
Wind Power
Solar Power- Ground Mounted
BioPower
Small Hydro Power
Solar Power- Roof Top
Waste to Power
Figure 1: Installed Capacity of Renewable
Energy in India as on 30-11-2017 (Source:
MNRE/CEA)
5502
5526
The cumulative installed capacity of grid
renewable power has reached to 57,244 MW at
the end of FY 2016-17, which accounts for
17% of grid renewable power installed
capacity from all resources. The aggregate
57,244 MW grid renewable power installed
capacity includes 32,280 MW from Wind
power, 12,289 MW from Solar power, 4380
MW from Small Hydro Power and 8295 MW
from Bio-Power as shown in the figure 2.
6000
185
106
305
219
1000
2312
2079
1112
296
252
2000
946
790
171
3000
1700
4000
3423
3019
5000
656
627
237
Installed Capacity (MW)
setting up of grid connected solar power
capacity from 20,000 MW to 1,00,000 MW by
2022 under the NSM. The above capacity is
proposed to be achieved through deployment
of 40,000 MW of rooftop solar projects and
60,000 MW medium& large scale solar
projects.
In order to harness the solar potential
efficiently and to achieve the objectives of
NSM, it was required to develop State level
Infrastructure solely dedicated to promote
solar power generation. One of the ways of
achieving that was development of solar parks
in a focused manner across different parts of
the country.
The solar park is a large chunk of contagious
land
developed
with
all
necessary
infrastructures like approach & access road,
water facility, power evacuation infrastructure,
metrological
station, telecommunication
infrastructure etc. Solar Park also facilitates
developers by reducing the number of required
approvals. The most important benefit from the
solar park for the private developer is the
significant time saved. The solar parks
facilitate the solar project developers to set up
projects in a plug and play model.
2. Solar Energy Status in India:
India’s Power Sector has predominantly been
based on fossil power and use mostly
domestically produced coal to generate
electricity. The country has been rapidly
adding
generating
capacity
since
Independence largely due to economic growth,
rising population, rapid urbanization leading to
rise in demand. The utility electricity sector in
India has one National Grid with an installed
capacity of 330.86 GW as on November, 2017.
India is the world's third largest producer and
fourth largest consumer of electricity. The
gross electricity consumption was 1,122 kWh
per capita in the year 2016-17. The per capita
electricity consumption is low compared to
many countries despite cheaper electricity
tariff in India. The contribution of power from
renewable energy sources contributes about
17% and that of solar power is more than 4%
in the overall energy mix as shown in figure1.
The growth of around 90% has been achieved
with capacity addition of 22,256 MW grid
renewable power during last three years (2014-
0
2012-13 2013-14 2014-15 2015-16 2016-17
Wind Power Solar Power
Bio Power Small Hydro
Figure 2: RE sectors wise progress during
last 5 years
However, the main challenges being faced in
conventional power generation include
depleting coal reserves in India, difficulty in
procurement of imported coal and long
gestation periods of coal-based power plants.
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India, with its large population and rapidly
growing economy, needs access to clean, cheap
and reliable sources of energy. India lies in the
high solar insolation region, endowed with
huge solar energy potential with most of the
country having about 300 days of sunshine per
year with the daily solar radiation incident
varies from 4 - 6 kWh per square meter of
surface area depending upon the location and
time of the year.
Government of India has taken up renewable
energy as an article of faith and set up an
ambitious target of 175 GW installed
renewable capacity by 2022. Out of 1,75,000
MW, 1,00,000 MW is proposed to be achieved
through solar energy. As on October 2017,
around 14,800 MW solar power projects have
been installed in the country.
The Government is promoting solar energy
through fiscal and promotional incentives,
such as capital subsidy, generation-based
incentive, accelerated depreciation, viability
gap funding (VGF), financing solar rooftop
systems as part of home loan, concessional
custom duty, exemption from excise duty and
foreign direct investment up to 100 per cent
under the automatic route, etc.
There is tremendous opportunity for foreign
investment in India in solar sector as foreign
direct investment is permitted under the
automatic route. Reserve Bank of India (RBI)
has announced renewables including solar
energy as priority sector. This will enable
banks to provide loans up to a limit of Rs 150
million to borrower companies of renewable
energy. For individual households, the loan
limit has been set to Rs 1 million per borrower.
Ministry of Finance has accorded in-principle
approval for issuance of tax free infrastructure
bond of Rs. 5000 crore for funding renewable
energy projects.
India has taken another initiative to create an
International Solar Alliance (ISA). It will be a
group of around 120 countries working for
development and promotion of solar energy.
India as founder member of this alliance has
offered to have its secretariat and also
committed some financial contribution.
3. Growth of Solar Capacity
Prior to the launch of National Solar Mission,
only 11 MW of solar capacity was installed.
However, after the launch of the NSM and
other State policies encouraging solar energy
generation, the solar capacity grew at a rapid
pace. Total solar capacity installed of about 1
GW was added upto the 11th Plan Period and
about 9 GW were added in 12th Plan Period. In
last five years, solar energy sector has grown
at a rapid pace. As shown in figure 3 the
installed capacity of solar projects has
increased from 2,632 MW in 2013-14 to
16,675 MW in 2017-18 .
16675
12288
6763
3
11
36
2632
1030 1686
3744
Figure 3: Cumulative Installed capacity (in
MW as on 30-11-2017, Source: MNRE/CEA)
Out of the above solar capacity, the 10 states
contribute about 90% of the total capacity
installed as shown in figure 4.
3500.00 2990.07
3000.00
2310.46
2165.21
2500.00
1819.42
1800.85
2000.00
1500.00
1000.00
500.00
1304.11
1184.86
876.80
521.88
509.38
0.00
Figure 4: Top ten states in Solar Capacity (in
MW)
4. Solar Manufacturing in India
One of the NSM’s objectives is to take global
leadership role in solar manufacturing across
the value chain of leading edge solar
technologies and target a 4-5 GW equivalent
installed capacity by 2020. The Mission
statement mentions setting up of dedicated
polysilicon manufacturing capacities sufficient
to cater to produce 2 GW worth of solar cells
annually.
In India, most manufacturing capacity was idle
or operating at low utilisation rates, primarily
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because it is uncompetitive due to lack of scale,
low-cost financing, and underdeveloped
supply chains. Solar manufacturing in India
started after the announcement of the NSM.
The present cell and module manufacturing
capacities in India are given below:
Module
Cell
10000
7746.44
6817.12
2.5
6000
4000
2731
2689
2000
1.75
1.5
Module
2500
2257.19135
3
2000
1500
1000
743.275
500
171.383
2013-14
682.57
332.839
2014-15
0.59
0.52
0.48
0.34
2017-18
2016-17
2015-16
0
Module Cost…
Figure 7: Declining Module Cost
5. Trend of Solar Tariff
Calculation of tariff depends on various factors
that include location, solar irradiance in the
State, availability of conducive State policy for
solar, availability of land, the cost of financing
and business environment, willingness of
DISCOMS to purchase the solar power, power
evacuation infrastructure, etc.
18
960.962
0.6
0.5
20
1418.161
1
2014-15
Figure 5: Installed and Operation Capacity of
Solar Module & Solar Cell
In respect of installed and operation capacity in
India, actual production capacity is quite low
as shown in figure 6 that in year 2013
production of module & cell was 743 MW &
171 MW respectively and now in 2016-17 the
production is around 2257 MW & 682 MW
respectvily.
1
2013-14
Operational capacity
2012-13
Installed capacity
2011-12
0
0
2.2
2
2010-11
8000
tariff is Rs. 5.68 per kWh. The cost of PV
modules have since continuously been
reducing over the period with advancement of
technology as well as with significant
improvement in global supply scenario. In
view of the falling cost of PV modules, the
tariff of solar PV projects have also been
declining significantly as in the graphically
representation of figure 8 below.
17.91
16
14
420.687
12
2015-16
2016-17
Figure 6: Year wise production of Solar
Module and Solar Cell
The solar projects under Phase-1 of National
Solar Mission were set up during the period
2010-11 to 2011-12. For the period 2010-11,
CERC determined the project cost of solar PV
projects as Rs.16.90 Cr. / MW based on the
prevalent PV module prices (US$ 2.2/Wp) and
the corresponding tariff as Rs.17.91 per kWh.
The project cost determined by CERC for the
period 2016-17 is Rs. 5.30 Cr./MW based on
the PV modules prices of US$0.48/Wp.
Declining module cost year wise is as shown
in the figure 7.The corresponding solar PV
10
8
6
4
7
6.45
6.47
6.17
4.34
3.30
2.44
2
0
Figure 8: Year-wise lowest solar tariff (in Rs.
/kWh)
Pursuant to successful bidding of solar projects
under NSM, the solar projects which are being
set up under the State Scheme are mostly
selected through a process of tariff based
competitive bidding and reverse auction. This
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method of selection has brought down the solar
average
bid
tariff
discovered
in
bidding/auctions significantly from a level of
Rs. 17.91 per kWh in December, 2010 to about
Rs.2.97 per kWh in February, 2017. Tariff in
Indian solar market changed regularly as
shown in Figures that the weighted average
tariff varies from Rs. 17.91 per unit to Rs. 2.44
per unit. The declining trend of solar power
tariff during the period from 2010-11 to 201718 is shown below in figure 8 below:
The recent downward trends in solar tariff may
be attributed to the factors such as economies
of scale, assured availability of land, and
power evacuation systems under the solar
parks.
6. Concept of solar Park
The concept of solar park was conceived from
Charanka Solar Park in Gujarat, and closely
followed by the Bhadla Phase-I Solar Park in
Rajasthan. Solar power projects can be set up
anywhere in the country. To set up solar
projects, a solar project developer is required
to identify and acquire the required land along
with all necessary statutory clearances required
from the concerned Government, arrange other
infrastructure facilities like approach road,
water, telecommunication facility etc., develop
transmission infrastructure for evacuation of
solar power to the nearest grid substation. The
above process is required to be followed by
every solar project developer for setting up
solar projects. It generally takes a longer time
for project developers to acquire land, get
change of land use and various permissions,
etc. which delays the project.
The solar projects scattered in multiple
locations lead to higher project cost per MW
and higher transmission losses. Total cost of a
solar project depends on multiple factors such
as solar insolation at a particular site,
infrastructure facilities required to be
developed, logistics, cost of funding,
prevailing prices of solar cells/modules and
related policies of the Government.
Solar Parks can be instrumental in overcoming
the bottlenecks otherwise faced by
independent power producers in a solar PV
plant, related to land availability, developing
evacuation infrastructure and its funding and
other financial challenges. To overcome these
challenges, the scheme for Development of
Solar Parks has been introduced in December,
2014.
A solar park is large contiguous stretch of land
with high insolation levels and provides
developers an area that is well characterized
with proper infrastructure and access to
amenities and where the risk of the projects can
be minimized.
A solar park facilitates assured availability of
land and transmission infrastructure facilities
for setting up higher capacity of solar projects,
reducing the number of approvals required,
minimizing time of setting up solar projects
thereby provide both economy of scale for
cost-reduction and achieving large scale
reduction in GHG emissions.
The solar parks provide specialized services to
incentivize solar project developers to invest in
solar projects in the park. These services while
not being unique to the park, are provided in a
central, one-stop-shop, single window format,
making it easier for investors to implement
their projects within the park in a significantly
shorter period of time, as compared to projects
outside the park which would have to obtain
these services individually.
In addition, the park provides road access (both
approach roads and smaller access roads to
individual plots), water (via a dedicated
reservoir located within the premises),
boundary fence and security, each of which
would have entailed additional costs for the
developer outside the park.
Each of these specialized services offer
significant benefits to the project developers
but come at a premium. Land plots within the
solar park are more expensive than outside.
But this premium is easily justifiable by these
services, which are bundled into the land cost.
However, the most important benefit from the
park for the project developer is the significant
time saved. The centralized, single window
nature of the services within the park reduces
the time between project conceptualization and
operations, translating into economic and real
monetary gains for the project developers and
the State.
The capacity of the solar park has been kept at
500 MW and above level in order to achieve
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economy of scale for cost-reduction. However,
smaller parks can also be set up in hilly areas
where contiguous land may be difficult to
acquire in view of the difficult terrain and
where there is acute shortage of nonagricultural lands.
A systemic representation of the concept of the
solar park is given in figure
transmission line to connect with the existing
network is therefore, required to be set up
either by CTU or STU. Setting up of substation nearby the solar park and creation of
transmission line to connect with the existing
network of CTU/STU is termed as external
power evacuation system.
7. Operational Structure:
The State Governments willing to set up solar
parks first identify an agency for development
of solar park. The agency entrusted with the
responsibility of setting up of solar park is
termed as Solar Power Park Developer
(SPPD). A State Government may select SPPD
in any of the following four modes:
Modes for selection of SPPD
Figure 9: Systemic representation solar park
The solar park is divided into several plots
based on the topography & availability of the
land and suitability of power evacuation
arrangement. Here in above figure, P1, P2 &
P3 are the individual plots and A1, A2…B6 are
solar projects inside the plots of the solar park.
The power generated from the individual
projects pooled to a nearby pooling station. For
this each plot is interconnected with pooling
stations through 33kV/other suitable voltage
underground, over ground or overhead cable.
The construction of this line from the solar
projects up to the pooling station is the
reponsibity of the Solar Project Developers
(SPDs).
The Solar Power Park Developer (SPPD) is
responsible to set up, internal transmission
system to evacuate the power from the solar
park. The internal transmission system consists
of setting up of the pooling stations (with
33/220 kV or suitable voltage level) inside the
solar park and will also draw transmission line
to transmit power from pooling station to the
nearest sub-station of Central Transmission
Utility (CTU) or State Transmission Utility
(STU) at 220 KV/400 KV or suitable voltage
level.
The solar power from the solar park needs to
be evacuated to the existing grid. A gridsubstation (220 KV/400 KV or suitable voltage
level) right adjacent to the solar park and
Mode I
The State designated nodal agency, could
be a State Government Public
Sector Undertaking (PSU) or a Special Pu
rpose Vehicle (SPV) of the State Govern
ment.
A Joint Venture Company between the
State designated nodal agency and SECI with 50:
50 % equity.
Mode III
Mode II
The State designates SECI as the nodal ag
ency on behalf of State Government on m
utually agreed terms.
Private entrepreneurs without any equity particip
ation from SECI, but may have equity participati
on from the State Government or its agencies.
Mode I
V
The SPPD is tasked with acquiring the land for
the park, cleaning it, leveling it and allocating
the plots for individual projects. Apart from
this, the SPPD are also entrusted with
providing the necessary facilities like approved
land for installation of solar projects and
required permissions including change of land
use etc; road connectivity to each plot of land;
water availability for construction as well as
running of power plants; flood mitigation
measures like flood discharge, internal
drainage etc; power during construction;
centralized weather monitoring station;
telecommunication
facilities;
power
evacuation facility consisting of pooling
stations to allow connection of individual solar
projects with pooling station through a
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network of underground/over ground cables or
overhead lines; housing facility for basic
manpower wherever possible; parking,
warehouse etc.
8. Progress and Status
The Scheme for Development of Solar Parks
was rolled out in December, 2014 by
Government of India. It was planned to set up
at least 25 solar parks, each with a capacity of
500 MW and above, thereby targeting around
20, 000 MW of solar power installed capacity;
in a span of 5 years commencing from 201415. Smaller parks are also allowed in
Himalayan region & other hilly States where
contiguous land is difficult to acquire in view
of difficult terrain and in States where there is
acute shortage of non-agricultural land.
Considering the demands for more solar parks
in States, the capacity of the solar park scheme
is enhanced from 20,000 MW to 40,000 MW
in March, 2017. All these solar parks are
proposed to be set up by 2019-20.
As on October 2017, 35 solar parks with
cumulative capacity of 20,503 MW have been
approved in 21 States as shown in figure 10
these solar parks are in different stage of
development. In addition to the above recently
500 MW solar park approved for Tamil Nadu
by TNEB Ltd.
have been acquired for 9 solar parks namely
Radhnesada solar park in Gujarat, Bhadla PhII, Bhadla-III Solar Park & Bhadla IV solar
parks in Rajasthan, Ananthapur-II & Kurnool
solar parks in Andhra Pradesh and solar parks
in Meghalaya, Uttarakhand and Uttar Pradesh.
Further more than 90% of required land have
been acquired in five solar parks namely
Ananthapur-I & Kadapa solar parks in Andhra
Pradesh, Pavagada solar park in Karnataka,
Rewa solar park in MP, Aamguri solar park in
Assam as shown in the figure 12.
Power Purchase Agreement (PPAs) have been
signed for around 4545 MW of solar projects
inside various solar parks; out of which 2230
MW of have been commissioned. Further,
tenders for additional 2500 MW have been
issued for which PPAs are yet to be signed.
Solar Projects inside the five solar parks have
already been commissioned as shown in the
figure 11.
1600
1500
Total Capacity
(MW)
Capacity Commissioned
(MW)
1400
1200
1000
1000
1000
800
680680
500
600
400
200
250
250
200
50
0
Figure 11: Solar projects commissioned
inside various solar parks
Figure 10: Solar Parks in India
The land of around 1,11,000 acres have been
identified & 66,000 acres of land have been
acquired in various solar parks. 100% land
9. Remarkable Case Studies
Kurnool Solar Park (1000 MW) in Andhra
Pradesh: The Kurnool Solar Park of capacity
1000 MW has already been commissioned and
is operational since March, 2017. Around 240
MU of clean energy is generated from this park
till end of May resulting in savings of 2.1 Lakh
tones of CO2 emissions.
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(a)
(b)
(c)
(d)
Figure 13 Kurnool Solar Park in AP (a)
Kurnool Solar Park (1000 MW
commissioned) (b) Anantpuramu Phase –I
solar park (250 MW commissioned) (c)
Pooling substation of NP Kunta site and
Kurnool site and (d) ground level water
reservoir with rain water harvesting at
Kurnool
With commissioning of 1000 MW capacity at
single location, Kurnool Solar Park has
emerged as the World’s Largest Solar Park
after Longyangxia Dam Solar Park of capacity
850 MW in China which was commissioned in
the year 2016.
Pavagada Solar Park (2000 MW) in
Karnataka: The Pavagada Solar Park in
Karnataka (2,000 MW), would be the largest
solar park of it’s kind after Tengger Desert
Solar Park of capacity 1500 MW in Zhongwei,
Ningxia of China which is under construction
and also known as the “Great Wall of Solar” in
China. Pavagada Solar Park in Karnataka has
the potential to be the largest solar park in the
world once completed. Here, 200 MW solar
photovoltaic projects along with 15 minutes
energy storage facility through battery for peak
smoothening is also proposed to be set up by
Solar Energy Corporation of India (SECI).
Rewa Solar Park (750) in Madhya Pradesh:
Rewa Solar Park in Madhya Pradesh brought a
revaluation in tariff of solar power in Indian
market by achieving the lowest ever levelized
tariff of Rs. 3.30/kWh through competitive
bidding of 750 MW. The tariff so discovered
depends inter alia on multiple factors like the
long-term and concessional debt from World
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Bank, three level payment security mechanism
through Letter of Credit, Payment Security
Fund, State Guarantee, power purchase tied
directly with end procurers like Madhya
Pradesh Power Management Corporation Ltd.
(MPPMCL) and Delhi Metro Railway
Corporation (DMRC) etc.The tariff of Rewa
Project is not unviable; rather it is low on
account of its better project structure,
bankability, balanced risk allocation, preidentified available land, the readiness of
internal and external evaluation structure, and
a soft loan from the World Bank.
The projects (three units each of 250 MW)
were awarded to the three successful bidders.
The tariff of Rs. 2.97, Rs. 2.974, and Rs. 2.979
per kWh discovered for the three 250 MW
units each of Rewa park is the first-year tariff
with 5 paise per year increase for 15 years. The
levelized tariff for 25 years of Rewa Solar Park
projects would be around Rs. 3.30/kWh.
Kadapa Solar Park (1000 MW) in Andhra
Pradesh: The Kadapa Solar Park in Andhra
Pradesh (1,000 MW) being developed by
APSPCL has also set a new record after the
success of Rewa Solar Park as the tariff
discovered for 250 MW project is Rs. 3.15 a
unit.
Bhadla Phase IV Solar Park (500 MW) in
Rajasthan: In Bhadla Phase-IV Solar Park at
Bhadla, Jodhpur, Rajasthan being developed
by JVC of State Government of Rajasthan and
M/s Adani Renewable, the lowest tariff
discovered is Rs. 2.62 per unit for 250 MW by
SECI under the VGF scheme.
Figure 14: 680 MW Solar Park Bhadla Ph-II
in Rajasthan
Bhadla Phase III Solar Park (1000 MW) in
Rajasthan: The Bhadla Phase III Solar Park in
Rajasthan is being developed by a JVC of State
Government of Rajasthan and IL&FS. SECI
invited the bids for 500 MW solar projects
inside Bhadla-III solar park and the lowest
tariff discovered for 200 MW is Rs. 2.44 per
unit followed by Rs. 2.46 per unit for 300 MW
under the VGF scheme.
10. Issues & Challenges
The concept of solar parks has indeed emerged
as a powerful tool for the rapid development of
solar power projects in India. Assured
availability of land and transmission
infrastructure are the major benefits of a solar
park. The recent downward trends in solar
tariff may be attributed to the factors like
economies of scale, assured availability of land
and power evacuation systems under solar
park.
The Solar Park Scheme aims to provide a huge
impetus to solar energy generation by acting as
a flagship demonstration facility to encourage
project developers and investors, prompting
additional projects of similar nature, triggering
economies of scale for cost-reductions,
technical improvements and achieving large
scale reductions in GHG emissions. It would
enable States to bring in significant investment
from project developers, meet its Solar
Renewable Purchase Obligation (RPO)
mandate
and
provide
employment
opportunities to local population.
However, the development of solar parks has
various issues and challenges as given below:
(i) Land: Land is a very critical input for
development of solar park. The requirement of
land is approximately 4-5 acres for the setting
up of solar parks. Land for the setting up of
solar park is generally identified by the
State/UT Government unless the SPPD has its
own land. It is the responsibility of the State
Government to help in making the land
available if the SPPD selected by the State
Government needs help. States are encouraged
to identify sites receiving good solar radiation
and sites which are closer to CTU, preferably
locations with spare transmission capacities
and water availability. However, private
entrepreneurs selected by the State
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Government as SPPD are allowed arrange their
own land for setting up the solar park. Land are
generally taken on long term lease from
Government as well as private sources. In such
cases, the State Governments are required to
ensure that the land is free from any dispute.
The park provides opportunity for all
technologies in a technologically agnostic
fashion.
In order to provide for such a large tract of
contiguous land with appropriate insolation
levels, the state governments are advised to
prioritize the use of government waste / nonagricultural land in order to speed up the
acquisition process. The inexpensive land are
preferred in order to keep the land cost as low
as possible and attract the developers. The land
owned by the State Government is given
priority and efforts are made to acquire private
land as minimum as possible. If land cannot be
made available in one location, then land in
few locations in close vicinity are also taken.
The acquisition of land for solar park is one of
the biggest challenges. Various state
governments have announced favorable land
policies that have been instrumental in
reducing this hassle. Some of the cases of
acquisition of land are hereunder:
In Rajasthan, the State Government under its
Solar Policy, 2016 has announced availability
of land to the developers at lowest cost. There
are six solar parks in Rajasthan and in all the
cases; the State Government has made the
required land available to the park developers.
Most of the lands allotted for solar parks are
Government land and there was no land
conversion charge whereas the stump duty was
5-6% of the value of the land.
In Andhra Pradesh, there are four solar parks
being developed by AP Solar Power
Corporation Pvt. Ltd. (APSPCL), a joint
venture company of Solar Energy Corporation
India (SECI), Andhra Pradesh Power
Generation Corporation (APGENCO) and
New & Renewable Energy Development
Corporation of Andhra Pradesh Ltd.
(NREDCAP). In all the cases, the park
developer tried to select government land.
However, there are also assigned and patta
land. A negotiation committee comprising of
local revenue authorities is constituted by the
government of Andhra Pradesh for direct
negotiation with farmers to finalise the
compensation payable to different categories
of land to enable speedy acquisition of land.
For acquisition of government land, assigned
land and patta land following process is being
followed in Andhra Pradesh as shown in the
figure 16.
Figure 16: Land acquisition process in
Andhra Pradesh
APSPCL, the Solar Power Park Developer in
Andhra Pradesh is facing various issues in
acquisition of land for the solar parks.
APSPCL has selected the land, maximum of
which belongs to the State Government. The
State Government usually assigns certain
Government lands to land less poor by giving
assignment. The Government can take back
these assigned lands for its own use by paying
suitable compensation on par with the patta
lands. Before paying compensation to these
assigned lands, the revenue department calls
land owners/farmers for original assignment
and other relevant records for verification. The
issue arises when the farmers fail to submit the
records for claiming compensation. The
revenue department denies compensation to
these farmers who fail to submit he records.
These farmers regularly come to site and stop
the works.
Further while granting assignment to land less
poor, the Government stipulates condition to
the farmers to bring the land in to the
cultivation within three years. If the farmers
don’t bring the land into cultivation within
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three years, the assignment granted to the
farmers will be cancelled and the farmer is not
eligible for any compensation. These types of
farmers also come to site and stop the works.
Some of the farmers approach court seeking
compensation for these types of lands. Some
farmers deny claiming compensation and want
to retain his assigned land for his livelihood. In
some cases, it is not possible to delete this land
from acquisition if the land is in the middle of
acquired land. In such cases the farmers
approach courts and comes to site and stops the
works.
In Karnataka, 2000 MW solar park is being
developed by Karnataka Solar Power
Development Corporation Ltd. (KSPDCL); a
joint venture company of Karnataka
Renewable Energy Development Ltd.
(KREDL) & SECI. The uniqueness in land
acquisition for the Pavagada solar park in
Karnataka is that the entire land of 13000 acres
is private land and taken on lease for a period
of 28 years which is first of its kind in World
with ownership of land vesting with land
owners, as acquiring of land is a major hurdle
in implementation of any project. The land
owners will be getting land lease charges of Rs.
21,000/acre/annum with 5% escalation once in
every two years on the base rate. Pavagada is
one of the most backward Taluks in the state of
Karnataka. The area is dry and due to lack of
water for irrigation, the farmers are suffering
due to lack of source of employment.
Establishment of solar park in this area will
create local employment to the public in a large
extent and will improve the revenue to the
Government.
In states like Madhya Pradesh, Uttar
Pradesh, the land is mostly Government
owned and there is as such no problem in
acquisition of land.
In Haryana, a solar park of capacity 500 MW
is being developed by Saur Urja Nigam
Haryana Ltd (SUN Haryana). Sun Haryana is
facing challenges in acquisition of land as the
panchayat land lease policy of Government of
Haryana does not allow sub-leasing of land.
However, sub-leasing of land to SPDs is
required for setting up of solar projects.
In Maharashtra, there are three solar parks
each of capacity 500 MW. Out of these three
solar parks, two solar parks are being
developed by private entrepreneurs. Both the
private entrepreneurs are facing challenges in
acquisition of land. Further, incidence of stamp
duty for non-agricultural lands is much higher
than the duty payable for agricultural land. In
order to address this, issue the government
decided to exempt industries covered under the
industrial policy from payment of stamp duty.
However, solar parks and solar projects are not
included as an industry as per this policy. The
land conversion charges and stamp duty
charges which are under the ambit of the State
Governments. Incidence of stamp duty would
escalate the cost of solar parks exorbitantly.
(ii) Financing: Significant investment is
required to be made for development of solar
parks which include acquisition of land, get the
land developed and provide necessary
infrastructure
like
road
connectivity,
transmission infrastructure etc. Further,
investment is also required to be made in the
operation & maintenance of solar parks,
employing staff and other activities like
marketing etc. The entire cost of development
including cost involved in acquisition of land
forms the total cost of the project.
Under the Solar Park Scheme, the Government
of India provides Central Financial Assistance
(CFA) of up to Rs. 20.00 lakh per MW or 30%
of the project cost including grid-connectivity
cost, whichever is lower, for development of
the solar park. While CFA covers only part of
the park cost, the remaining amount is being
taken from the Solar Project Developers
(SPDs) as one-time upfront charges and
recurring O&M charges, when they enter the
park to set up solar projects. This financial
model is being adopted in most of the solar
parks. Few cases are given as under:
In Andhra Pradesh, APSPCL is meeting their
financial requirement for development of solar
parks partly by Central grant (Rs. 12.00
Lakh/MW) and the balance fund is met by
collecting one-time solar power development
expenses (around Rs.40 Lakh/MW) from the
solar power developers (SPDs). Further, O&M
charges (Rs.2.50 to 3.00 lakh/MW) are also
collected annually from the SPDs to meet the
yearly expenditure to be incurred towards
maintenance of solar power park.
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In Karnataka, KSPDCL is meeting their
financial requirement for development of solar
parks partly by Central grant (Rs. 12.00
Lakh/MW) and the balance fund is met by
collecting one-time solar power development
expenses (around Rs.28 Lakh/MW) from the
solar power developers (SPDs). Further, O&M
charges (Rs.2.50 to 3.00 lakh/MW) are also
collected annually from the SPDs to meet the
yearly expenditure to be incurred towards
maintenance of solar power park.
In Bhadla Phase-II solar park of Rajasthan,
Rajasthan Solarpark Development Company
Limited (RSDCL) is meeting their financial
requirement for development of solar parks
partly by Central grant (Rs. 12.00 Lakh/MW)
and the balance fund is met by collecting onetime solar power development expenses of Rs.
6.00 Lakh/hectare. Further, O&M charges (Rs.
30,000/- per annum per hectare) are also
collected annually from the SPDs to meet the
yearly expenditure to be incurred towards
maintenance of solar power park.
The onetime charges put an upfront burden on
the selected SPDs. In order to reduce this
burden, Ministry of New and Renewable
Energy is tying up with different bi-lateral and
multi-lateral financing agencies for long tenure
and concessional loan for development of solar
parks. The long tenure and concessional
financing from bi-lateral and multi-lateral
financing agencies would be utilized in
development of the internal infrastructure,
such as, internal transmission system, water
access, road connectivity, communication
network, etc. of the solar parks. With low cost
financing, the solar power generated in the
solar parks is expected to be cheaper.
The Rewa Solar Park in Madhya Pradesh is
one of the solar parks availing World Bank
loan for development of park infrastructure.
The World Bank loan has a component called
Clean Technology Fund (CTF), the USD
interest rate of which is 0.25% per annum fixed
over the life of the loan. The door-to door tenor
of IBRD financing is 24 years and that of the
CTF could be 40 years. The Rewa solar park is
financed by combination of the following three
components:
a) Central Financial Assistance (CFA) from
Government of India under the scheme for
“Development of Solar parks and Ultra Mega
Solar Power Projects” @ Rs. 12 Lakh/MW or
30% of the cost of development of internal
infrastructure of solar park, whichever is lower.
It may be treated as part of equity of the SPPDs;
b)
SPPD’s internal resources (equity of
the SPPDs or land contribution) and annual
park charges / user fee to be charged from the
selected SPDs. However, collection of upfront
charges by the SPPDs from the SPDs is not
allowed for the financial assistance received
from the World Bank and Central Grants
received from MNRE.
c)
Financial assistance from World Bank.
However, the financial assistance from World
Bank would be limited to 50% of the total cost
of development of internal infrastructure of the
Solar Park.
(iii) Grid Integration of Solar Parks: In case
of large scale renewable generation,
particularly for large scale solar parks, it is not
possible to absorb the energy locally. The
scenario is more prominent especially during
the period of high solar generation wherein
electricity demand is not at peak level.
Transmission system is required to be planned
for integrating such large scale solar power
parks with the State grid as well as with the
inter-state/national grid. Integrated planning
approach would ensure that solar generation
does not have to be backed down during solar
maximized scenario or other than peak demand
period and local grid network must be stable
even when solar generation is not available
during night time. This integration provides
reliability of transmission and power supply to
the whole system. Owing to intermittent nature
of solar energy, it requires support from the
grid. The transmission capacity requirement
for grid integration of solar parks shall also
depend upon quantum of power to be
transmitted/integrated. Once all the solar parks
are commissioned, solar projects of aggregate
capacity 40 GW would be connected to the
grid.
To evolve plan for grid integration of large
scale solar/wind generation capacities,
POWERGRID has been entrusted by Ministry
of Power (MOP) to formulate Grid Integration
Plan for envisaged renewable capacity addition
by 2022 as Green Energy Corridors-II. The
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scope of Green Energy Corridors-II includes
identification of transmission scheme, its
implementation, financing strategy etc. The
power evacuation arrangement for the
identified solar parks approved under Pahse-I
of the Solar Park Scheme envisaged through
Intra state & Interstate evacuation is evolved as
Green Energy Corridors-II (Part-A). The
report on Green Energy Corridor-II covers the
plan for grid integration of solar parks at interstate level and intra-state level.
POWERGRID has carried out studies to
identify
transmission
infrastructure
requirement for solar parks in various states.
To carry out the studies, inputs like existing
generation data, information regarding details
of solar parks i.e. location, quantum and time
frame in various states, pocket wise RE &
conventional generation capacity addition
program in time frame of 2016-17 & 2018-19
has been considered. Information about
existing and planned transmission system
including various transmission corridors High
Capacity Corridors/Green Energy corridors,
wind and solar generation pattern, network
topology etc. has been taken into account in
studies. In order to facilitate transfer of power
from envisaged solar parks, inter-state & intrastate transmission scheme is evolved with total
estimated cost of Rs 12,786 crore.
(iv) Difference in Gestation period of Solar
Generation and Transmission: Gestation
period of solar projects is very less (12-18
months) vis-a-vis transmission development
(24-36 months) for integration with the grid.
Further, the capacity utilization factor for solar
generation is low resulting into high
transmission tariff. In view of the above,
Transmission
development
for
solar
generation faces two critical issues i.e.
matching implementation period (Generation
vis-a-vis Transmission) as well as transmission
tariff.
As per the prevailing regulation in India, interstate transmission system for generation
project is evolved based on Long Term
Access/Connectivity application by the
applicant. However, keeping in view of short
gestation period of RE, transmission
development need to be done much ahead of
generation
without
considering
LTA/Connectivity application. However,
location of the generation project and its
quantum needs to be firmed up in advance so
that transmission system planning can lead the
generation and its implementation may match
with solar generation development.
An approach should also be developed to build
the transmission for High potential RE zones
in anticipation of subsequent RE development
rather than waiting for RE project to first come
up with their requirements i.e. Transmission to
lead generation approach.
(v) Forecasting of Solar Generation: Solar
generation forecasting & its real time
monitoring are important tools to address
variability & uncertainty aspect of its grid
integration. State-of-the-art forecasting helps
grid operator to manage power system balance
for economic, reliable & secured operation of
the grid even in high RE penetration regime.
In this direction, establishment of Renewable
Energy Management Centers (REMC) colocated with SLDCs/RLDC/NLDC in RE
resources rich states was proposed as part of
Green Energy Corridor-I. REMC shall be
responsible for forecasting of RE generation in
their jurisdiction for different time horizons,
real time tracking of RE generation and close
co-ordination with their SLDC/RLDC for
smooth grid operation. It is proposed that the
envisaged solar parks shall be integrated with
these REMCs also for monitoring, scheduling
& forecasting purpose.
(vi) Ancillary Services: Ancillary Services,
defined as: "those services necessary to
support the transmission of electric power
from seller to purchaser given the obligations
of control areas and transmitting utilities
within those control areas to maintain reliable
operations of the interconnected transmission
system."
The two most important ones are the
a) Reserves of generation to support falls of
generation and with the goal to maintain
the frequency and interchanges in the case
of loss of some generation.
b) Maintain the voltage profile in the system
High Renewable penetration scenario
necessitates increased balancing and system
flexibility requirements. In such scenarios, to
ensure the reliability of the power system and
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quality of electricity, additional services viz.
Ancillary services may be needed by the
system operator to achieve system balancing in
real time. The Detailed Procedure for Ancillary
Services Operations for Inter-state has been
approved by CERC in March, 2016. The
Ancillary Services have been rolled out for
implementation in April 2016. Similar
framework needs to be implemented in the
states also.
11. Conclusion
The concept of solar parks has indeed emerged
as a powerful tool for the rapid development of
solar power projects in India. Assured
availability of land and transmission
infrastructure are the major benefits of a solar
park. The recent downward trends in solar
tariff may be attributed to the factors like
economies of scale, assured availability of land
and power evacuation systems under the Solar
Park Scheme. The issues/challenges can be
resolved by concerted efforts of all stake
holders. The major benefits of solar parks are
50,000 MW of solar projects can be set up
in 50 proposed solar parks in various States/
UTs of the country.
Availability of solar power at competitively
low tariffs. Total capacity when
operational, will generate 64 billion units of
green energy/electricity per year @1.6
million unit per MW.
Achievement of 40,000 MW solar
capacities would contribute to long term
energy security of country and ecological
security by reduction in carbon emissions
and carbon footprint, as well as generate
large direct & indirect employment
opportunities in solar and allied industries
like glass, metals, heavy industrial
equipment etc.
Installation of 40,000 MW of solar will lead
to abatement of around 56 million tons of
CO2 per year over its life cycle.
Creation of solar parks has attracted foreign
players to invest in solar projects in India.
More investment opportunities will enhance
income.
The solar parks will also provide productive
use of abundant wastelands which in turn
facilitate development of the surrounding
areas.
*****
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Interconnected Hybrid RE Network with Embedded VSC MTDC Transmission System for Secure and Efficient Power
Delivery: Modeling and Steady State Response Analysis
Jeetendra Singh Rathore, Mukesh Lodha, Shivani Johari, Rituraj Soni
Sri Balaji College of Engineering & Technology, Jaipur (Rajasthan)
Jsrathore9@gmail.com
Radhey Shyam Meena,
Ministry of New & Renewable Energy, New Delhi (India)
Corresponding Author: rshyam.mnre@gov.in
Abstract
This paper deals with one of the major challenge in the field of Indian Power Sector with a
objective of to provide a framework for promotion of large grid connected and interconnected
Renewable Energy (RE) networks for optimal and efficient utilization of transmission
infrastructure and land, reducing the variability in renewable power generation and thus
achieving secure and better grid stability with improved power quality at delivery end. The
proposed studies are going to encourage new technologies, methods and way-outs involving
combined operation of wind and solar PV power generation systems with embedded Voltage
Source Converter (VSC)-MTDC transmission system, to transmit bulk power, to control
power, to modulate power and to improvement in system stability. The paper focused on a case
study of two separate-interconnected systems through a DC transmission network of the
capacity of 24 kW wind power generation system and 24 kW solar power generation system
has been used for analysis of steady state response of the system. Performance of the system
and steady state response analyze using MATLAB techniques and is better then non-RE
network and also found in acceptable range for secure operation and better grid stability.
Key words: Integrated Solar Wind System, Interconnected Renewable Energy Network
(IREN), Multi Terminal Direct Current (MTDC) Transmission System, Voltage Source
Converters (VSC), Power Quality (PQ) of India Power Sector (IPS), Grid Stability (GS).
1.
Introduction
India has set an ambitious target of reaching
175 GW of installed capacity from
renewable energy sources including 100
GW from solar and 60 GW from wind and
plan for 10 GW solar wind hybrid capacity
by the year 2022 for which the Government
of India has launched several schemes for
promotion of solar and wind energy in the
country to achieve the target. The
Government is promoting renewable
energy through fiscal and promotional
incentives such as capital subsidy, tax
holiday on the earnings for 10 years,
generation based incentive, accelerated
depreciation, viability gap funding (VGF),
financing solar rooftop systems as part of
home loan, concessional excise and custom
duties, preferential tariff for power
generation from renewables, and foreign
direct investment up to 100 per cent under
the automatic route etc. The country has
already crossed a mark of 32 GW of wind
and 12.28 GW of solar power installed
capacity up to March 2017[1].
Solar and wind power being infirm in
nature impose certain challenges on grid
security and stability. Studies revealed that
solar and winds are almost complementary
to each other and hybdridation of two
technologies would help in minimizing the
variability apart from optimally utilizing
the infrastructure including land and
transmission system. Superimposition of
wind and solar resource maps shows that
there are large areas where both wind and
solar have high to moderate potential. The
existing wind farms have scope of adding
solar PV capacity and similarly there may
be wind potential in the vicinity of existing
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solar
PV
plant.
Suitable
policy
interventions are required not only for new
wind-solar hybrid plants but also for
encouraging hybridization of existing wind
and solar plants [2-3]. Performance and
feasibility explained in [4] for an integrated
hybrid system in which a solar cell, wind
turbine, fuel cell and ultra capacitor system
is developed using a novel technique to
complement each other. Hybrid renewable
energy systems in [5] help to increase
system reliability and improve power
quality. This paper explained the way to
integrate the power output from solar photo
voltaic array, fuel cell stack and battery
with a provision for on site hydrogen
generation by means of an electrolyzer and
H2 tank. The control strategy handles the
source power effectively by considering the
limited life cycle of storage devices. In [6]
one such novel initiative wherein electricity
requirement is fulfilled by renewable
energy presented. In this study, an
integrated hybrid system is used to generate
electricity from the combination of solar
and wind energy. Fuel cell and electrolyzer
also used for storage and better
performance on remote applications. A
combination of a solar cell, fuel cell, and
ultra capacitor system for power generation
was presented in [7]. In this work the
available power from the renewable energy
sources is
highly dependent
on
environmental conditions such as wind
speed, radiation, and ambient temperature.
Fuel cell and ultra capacitor system were
used to overcome the deficiency of the solar
cell and wind system. This system is used
for off-grid power generation in noninterconnected or remote areas. High
Voltage DC Transmission system is used to
transmit bulk power, to control power, to
modulate power for improvement in system
stability. Mostly voltage source converters
used as insulated gate turn of thyristor in dc
network. In [8] it was described the basic
modeling and simulation of voltage source
converter in HVDC are explained. In [9] it
was proposed to integrate large capcity
renewable energy into the existing power
grid, provide remote islands with reliable
power supply, and regulate the frequencies.
Though, to expand an existing traditional
point to point line controlled converter
HVDC line into hybrid MTDC system
achived [10]. One of the most suitable
applications of VSC-based MTDC
transmission systems is in the field of wind
farms interconnection. Of course there are
many publications which investigated the
possibility of utilizing CSC converters for
aggregation of offshore wind farms [11-13].
However, CSCs need for reactive power
support at the point of connection which
consequently leading the connected AC
system to have a high enough short circuit
ratio [14-15]. Some literature has proposed
that installation of Static Compensators
(STATCOM) at the point of connection
CSC terminal to offshore station can solve
this problem [16]. However, the proposed
solution brings about other issues such as a
wider footprint, more losses, and more
complexity in the wind power system.
Contrarily, based on VSC HVDC link
characteristics such as rapidly and
independently control of active and reactive
powers and black-start capability, these
VSC links are superior to CSC links for
wind farm grid interconnection [17-19].
That is why VSC links have been proposed
as a more rational and efficient solution to
be used for interconnection of wind farms.
Therefore, due to these especial
characteristics of VSC links, such systems
are mostly used for wind farms
interconnections. Reference [20] proposed
the construction of a low voltage DC grid
using VSCs to aggregate the power of
several wind turbine units. It has also
been proposed using hybrid MTDC
systems based on VSCs and CSCs for
subtransmission and distribution systems in
urban areas of large cities [21].
2.
An
Approach
towards
Integration
Under the integration category of windsolar hybrid power plants, Wind Turbine
Generators (WTGs) and Solar PV systems
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have been configured to operate at the same
point of grid connection. There can be two
different approaches towards integrating
wind and solar depending upon the size of
each of the source integrated and the
technology type. Here we concluded two
approaches i.e. (a) Technology front (b)
Size of the source
On the technology front, in case of fixed
speed wind turbines connected to grid using
an induction generator, the integration can
be on the HT side at the AC output bus.
However, in case of variable speed wind
turbines deploying inverters for connecting
with the grid, the integration can even be on
the LT side before the inverter i.e. at the
intermediate D.C bus. The second
important aspect would be related to the
sizing – which would depend on the
resource characteristics.
In order to achieve the benefits of hybrid
plant in terms of optimal and efficient
utilization of transmission infrastructure
and better grid stability by reducing the
variability in renewable power generation,
in the locations where the wind power
density is quite good, the size of the solar
PVs capacity to be added as the solarhybrid component could be relatively
smaller. On the other hand, in case of the
sites where the wind power density is
relatively lower or moderate, the
component of the solar PV capacity could
be relatively on a higher side. However, a
wind-solar plant will be recognized as
hybrid plant if the minimum ratio of total
rated capacity of WTGs and solar PV plant
is 1: 0.25.
The implementation of wind solar hybrid
system has depends on different
configurations and use of technology
detailed below:
(a) Wind-Solar Hybrid- AC integration:
In this configuration the AC output of the
both the wind and solar systems is
integrated either at LT side or at HT side. In
the later case both system uses separate
step-up transformer and HT output of both
the system is connected to common AC
Bus-bar. Suitable control equipment is
deployed for controlling the power output
of hybrid system.
(b) Wind-Solar Hybrid- DC integration:
DC integration is possible in case of
variable speed drive wind turbines using
converter-inverter. In this configuration the
DC output of the both the wind and solar
PV plant is connected to a common DC bus
and a common invertors suitable for
combined output AC capacity is used to
convert this DC power in to AC power.
3.
Modeling of Interconnected
Hybrid Network
In this section an interconnected hybrid
network of the wind and solar based
configuration is presented. With their
advantages of being abundant in nature
and nearly non-pollutant, renewable
energy sources have attracted wide
attention. Wind power is one of the most
promising clean energy sources since it
can easily be captured by wind generators
with high power capacity. Photovoltaic
(PV) power is another promising clean
energy source since it is global and can be
harnessed without using rotational
generators. In fact, wind power and PV
power are complementary to some extent
since strong winds mostly occur during the
night time and cloudy days whereas sunny
days are often calm with weak winds.
Hence, a wind–PV hybrid generation
system can offer higher reliability to
maintain continuous power output than
any other individual power generation
system.
This kind of hybrid generation system can
be divided into two main types—the
stand-alone off-grid system and the gridconnected system. For the grid-connected
system, the interface between the hybrid
generation system and the power grid has
to be specially designed. For the standalone off-grid system, the hybrid
generation system can easily be set up in
remote and isolated areas where a
connection to the utility network is either
impossible or unduly expensive. Over the
years, there has been only few research
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work on the standalone wind–PV hybrid
generation system in which the wind
generators are focused on induction
machines. The purpose of this thesis is to
present a new way of grid connected and
interconnected
wind–PV
hybrid
generation system with embedded VSCDC transmission system for secure and
efficient power delivery to the end users.
Solar System
The solar radiation resource is
fundamentally determined by the location
on the earth´s surface, the date, and the
time of day. These factors determine the
maximum level of radiation. Other factors
such as height above sea level, water vapor
or pollutants in the atmosphere and cloud
cover decrease the radiation level below
the maximum possible. Solar radiation
does not experience the same type of
turbulence that wind does but there can be
variations over the short term. Most often,
these are related to the passage of clouds.
Simulink blocks of the different
components in the experimental model are
shown in Figure. In the figure, these are
the PV array system block, inverter block,
three-phase source block, controller block
and the load block respectively. This
model also includes the MPPT model, in
the next chapter, these blocks will be
discussed individually will look into how
the models are implemented as shown in
figure 1 and figure 2.
This model based on 24 kW system which
design internally in figure1 and full
diagram as shown in figure 2.
Figure 1: Internal model of solar system based on the equations
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Figure 2: 24 kW PV system
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Wind System
Ultimately wind resources are driven
almost entirely by the sun’s energy,
causing differential surface heating, but
they tend to be very dependent on location.
Over most of the earth, the average wind
speed varies from one season to another. It
is also likely to be affected by general
weather patterns and the time of day. It is
not uncommon for a site to experience a
number of days of relatively high winds
and these days to be followed by others of
lower winds, strongly interfering with the
operation planning of a hybrid system
comprehending wind turbines. The wind
also exhibits short term (seconds to
minutes) variations in speed and direction,
known as turbulence.
The power output of wind turbine relates
to wind speed with a cubic ratio. Both the
first order moment of inertia (J) and a
friction based dynamic model for the wind
turbine rotor and a first order model for the
permanent magnet generator are adopted.
The dynamics of the wind turbine due to
its rotor inertia and generator are added by
considering the wind turbine response as a
second order slightly under-damped
system. Using this simple approach, small
wind turbine dynamic is modeled as
shown in figure 3 and figure 4.-
Figure 3: Internal Model of 3 kW wind system
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Figure 4: 24 kW Wind System
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Voltage Source Converter (VSC) Based
Multi Terminal Dc (MTDC) System
Two basic converter technologies are used
in modern HVDC transmission systems.
These are conventional line commutated,
current source converters (CSC) and self
commutated, voltage-sourced converters
(VSC). Two types of configuration can be
adopted in Multi Terminal DC (MTDC)
systems. The parallel connection which
allows DC terminals to operate around a
common rated voltage VDC. The second
configuration is the series connection
where one of the converters controls the
current around a common rated current
and the power is controlled by the rest of
converters. This configuration is well
suited for Current Source Converter
(CSC) MTDC systems since CSCs in the
DC side are functioning as a voltage
source which can be connected in series
without need for special switching.
Compared to CSCs, VSCs are functioning
as an ideal current source in its DC sides
allowing the parallel connection of several
DC terminals without posing any technical
difficulties. As perviously mentioned, in a
VSC link the direction of power can be
changed through the reversal of current
direction and the voltage polarity at the
DC side can remain unchanged. These
capabilities are perfectly suited for
constructing an MTDC system. VSC
MTDC systems with parallel connected
converters have a great potential to be used
in the future bulk power systems.
Possibility of such connections has led to
the proposition of a DC ’Super Grid’ that
could connect several renewable energy
sources to a common MTDC network.
Utilizing VSC-based MTDC systems can
give the following possibilities to the
power systems- (a) Control of the MTDC
system, (b) increasing the flexibility of
power flow controllability, (c) enhancing
transmission capacity, (d) improving the
voltage profile in the network, and
integrating large scale of renewable or
new energy sources positioning at
different locations.
VSC based multi terminal DC system
contains number of VSC’s either offshore
or onshore connected to same DC link.
VSC connected to generating station can
be offshore or onshore depending upon
renewable energy nature i.e. tidal energy,
offshore wind farms, solar panels etc. But
throughout this paper we will consider
offshore wind farms as it have more
capacity to generate electricity and can
meet the needs. Each offshore wind farm
requires an offshore substation used to
install VSC converter and number of
connections to DC link depends upon
MTDC application, same in the case of PV
system. Before designing MTDC system,
design engineer must consider technoeconomic factors imposed by utility.
Economic factors include geographical
location, number of offshore substations,
onshore platforms, DC link, DC Circuit
Breaker, ultra-fast mechanically actuated
disconnector, and cost. Technical aspects
can be: effective utilization of MTDC
lines, rating of DC link, protection of
MTDC under abnormal conditions and
support to connected AC network.
MTDC system must satisfy the security
and Quality of Supply Standard as well as
DC voltage of MTDC system must be
constant during abnormal conditions on
AC sides of VSC DC. Each terminal of
VSC based MTDC system must be able to
control active and reactive power, support
AC network voltage and frequency
independently. VSC based MTDC system
behavior strongly depends upon the
control nature which mainly rely on
system topology and kind of AC grid
connection.
Figure shows the VSC station model with
its elements. The model at the DC side is
depicted as single line representation. The
model consists of AC buses, coupling
transformer, series reactance, AC filter,
converter block on the AC side and on the
DC side, DC Bus, DC filter and DC line. As
it can be seen each VSC station is
connected to the AC grid at the so called
point of the common connection (PCC).
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PCC is connected to AC side of VSC
through a converter transformer, shunt filter
and finally phase reactor. On the other side
i.e. DC side, DC bus, at which a shunt DC
capacitor is connected to the ground, is
connected to the VSC from one side and to
DC line from other side as shown in figure
5.
.
Figure 5: VSC Station Model
Interconnected Network
In this work, a detailed dynamic model and
simulation of an interconnected hybrid
power system are developed using the
VSC topology. Modeling and simulations
are conducted using MATLAB/Simulink
software packages to verify the
effectiveness of the proposed system. The
results show that the proposed hybrid
power system can tolerate the rapid
changes in natural conditions and suppress
the effects of these fluctuations on the
voltage within the acceptable range and
supply power at end user with better
quality.
This system has 48 kW PV generation
System, a 48 kW wind energy system, a
500 kM DC transmission line and VSC
universal bridge for conversion purpose
used. It is used to step up voltage to DC
440 V and invert to Vrms, 50 Hz AC.
The renewable energy based hybrid
system model made in Simulink is shown
in Figure 6, 7 and 8.
Figure 6: Interconnected through a DC Transmission Network and VSC system
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Figure 7: System-I of Capacity 24 kW wind and 24 kW PV system
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Figure 8: System-II of 24 kW wind and 24 kW PV system
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Simulation Results of the Interconnected Network
Figure 9: Wind Solar Power
Figure 10: Hybrid Voltage
Figure: 11 Voltage and Current of Wind System
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Figure 12: 3-Phase Volatage of wind
Figure 13: Voltage and Current for Solar System
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Figure 14: 3 Phase Volatage for PV System
Figure 15: Out put Voltage of System 1
Figure 16: Out put voltage of System 2
Figure 17: Combined 3-Phase Volatge after Transmission
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Figure 18: Interconnected 3-Phase Voltage
The system presented in this study is
Figure 10 also illustrates that parallel
simulated under several conditions like
operation of the system continues without
different input voltages and different load
any interruption, even input voltages of
sharing ratios. Some of the simulation
the converters have different values. The
results are given in this section. As
ripple on the output voltage of the system
mentioned previously, the system is
is given in Fig. 17. It has been obviously
controlled by the PI control blocks. If the
seen that the ripple is quite less (1.2 V),
converters operate uncontrolled, some
around 0.385 %, which is highly
serious problems may occur like
considerable value. Moreover, this ripple
overshooting and instability.
has been minimized by controlling the
Figure 9 illustrates waveforms of wind and
converters
with
high
switching
solar power in the case of hybrid system.
frequencies without using an external
Figure 10 illustrates waveforms of wind
filter.
and solar voltage. Figure 11 illustrates
waveforms of Voltage and Current of
Steady State Response:
Wind System. Figure 12 illustrates
waveforms of 3 phase voltage of wind
system. Figure 13 illustrates waveforms of
Voltage and Current of PV System. Figure
14 illustrates waveforms of 3 phase
voltage of PV system. Figure 15 illustrates
waveforms of voltage in the case of hybrid
system for system 1. Figure 16 illustrates
waveforms of voltage in the case of hybrid
system for system 2. Figure 17 illustrates
waveforms of voltage in the case of
interconnected system. Figure 18
illustrates waveforms of 3 phase voltage in
the case of interconnected system.
Voltage and current signals when the
converters operate uncontrolled. Also,
parallel connection operation is achieved
in a very short time, around 0.3 s, which
means that the system has a fast response
time. In the study, another test is carried
out to observe the system response against
the load variations after the system is
passed to steady state conditions. The
system response against the load
variations is illustrated in Fig. 18 when the
load is shared equally. As depicted on the
figure, the load value is 100 ohm between
0 s and 1 s.
The presented load sharing system has
been also tested for different sharing
ratios. This situation can be observed in
Fig. 10, where the wind system feeds the
load with 70 % load ratio, and the PV
system feeds it with 30 % load ratio.
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sharing techniques in order to ensure power
flow control among the energy sources. The
system presented is also tested against the
instant load variations on the output side.
Negative effects of the load variations are
eliminated in a very short time and load
sharing
operation
is
maintained
successfully under new load conditions.
The system performance can satisfy the
user in all perspectives. It could regulate the
output power properly while its transients
were damped very quickly.
Figure 19: Bode Nichols and Pole Zero
Charstrstics for the System
Figure 19 explain the Bode Nichols and
Pole Zero Charstrstics for the System
Conclusion:
In this study, an effective parallel
connection model for interconnected hybrid
network has been developed to use it in
multi-input energy systems. Firstly, the
system is modelled and mathematically
analysed. Once the converter is
mathematically modelled, it is then
simulated in MATLAB/Simulink in order
to test the mathematical model and to
define the required circuit parameters.
Then, a model for parallel connection
operation is also developed and simulated
in MATLAB/Simulink. According to
simulation results, it has been observed that
ripples on the output voltage of the
converters are considerably minimized.
Furthermore, parallel operation of the
system has been maintained without any
interruption, even though the energy
sources have different input voltages.
Transient state analysis of the system is also
realized and it is observed that the system
reaches to steady state conditions in a very
short time. In the system presented, load
sharing operation among the converters is
carried out by realizing the active current
Reference:
1. Radhey Shyam Meena, Dr. Nitin
Gupta, Prof. D. K. Palwaliya, Dr. A. K.
Sharma "Integration of Solar Parks:
Global Impact of Intermittent RE
Generation" International Journal of
Research and Innovation in Social
Science -IJRISS vol.1 issue 4, pp.0715 2017
2. Radhey Shyam Meena, Dilip Nigam,
Dr. A. K. Tripathi, "Journey Towards
Sustainable Growth with Energy
Security and Global Tracking
Framework: Case of Hybrid Project"
Conference on Metering India 2017
towards smart and sustainable utilities
organized by IEEMA India with IEC,
MNRE & MoP, 06-07 April 2017
(Published Paper no. 41 of
proceeding).
3. Radhey Shyam Meena, Bharat Dubey,
Dr. Nitin Gupta, Dr. D K Sambariya, A
S Parira, M K Lodha, ’’ Performance
and feasibility analysis of integrated
hybrid system for remote isolated
communities’’ IEEE Publication, 2016
IEEE International Conference on
Electrical Power and Energy Systems,
ISBN 978-1-5090-2476- 6/16/$31.00
©2016 IEEE, December 2016.
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Dr. Nitin Gupta, M K Lodha ‘’Control
Strategy of a Stand-Alone Hybrid
Renewable Energy System for Rural
Home Application’’ IEEE Publication,
2016 IEEE Seventh India International
Conference on Power Electronics
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(IICPE 2016), ISBN 978-1-50904530-3/16/$31.00
©2016
IEEE,
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5. Radhey Shyam Meena, "Sustainable
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Communities Using Integrated Hybrid
System: A New Generation of
Renewable Energy'' Akshaya Urja,
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Renewable Energy, Volume 10 Issue
2, pp 42-45, October 2016.
6. Radhey Shyam Meena, Deepa Sharma,
Dr. D. K. Birla,”PV-Wind Hybrid
System with Fuel Cell & Electrolyzer”,
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No.4, Issue No.12, pp: 673-679, 01
Dec. 2015.
7. Radhey Shyam Meena, M K Lodha,
“Modeling and Simulation of Voltage
Source Converter in High Voltage Dc
System" International Journal of
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and
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2454 - 6119 Volume I, Issue II, 2015, p
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"Analysis of Integrated Hybrid VSC
Based Multi-Terminal DC System
Using Control Strategy", International
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Mitigation of Inrush Current in Power Transformer using Prefluxing
Technique
Avinash Yadav, Jyoti Kant Sharma, Shivani Johari, Mukesh Lodha
Sri Balaji College of Engineering & Technology, Jaipur (Rajasthan)
Swati Agariya
National Institute of Solar Energy, Gurugram, India 122005
Poonam Meena
DMRIPC Pvt. Ltd., New Delhi (India)
Email: rspunam2016@gmail.com
Corresponding Author: aviyadava@gmail.com , swati.agariya12april@gmail.com
Abstract:
Transformer is the most expensive component in power system. So this is very necessary to provide
sufficient protection for that component. There are many problems which may occur in transformer
like over current, overvoltage etc because of faults which can damage the transformer. Damage in
transformer can create a serious problem in transmission or distribution of system. Three phase
transformer produces severe starting current which is called inrush current. This inrush current
induces harmonics which is high in magnitude and generate at the time of re energisation of
transformer and it is 2 to 5 times greater than rated current. This current generates several problems
like mal operation of relays, damaging the windings and core of transformers. In this paper a
technique to mitigate inrush current in three phase transformer which involves injecting some amount
of DC flux in the primary of transformer has been proposed, this process is known as prefluxing.
After setting the initial fluxes of the transformer it is energized by conventional controlled switching.
To verify the effectiveness of the proposed prefluxing method and to mitigate inrush current for
transformer, a MATLAB®/simulation model is designed and developed.
Keywords: Inrush Current, Transformer, Prefluxing, MATLAB®/Simulink
to the magneto motive force (mmf) in the
1. INTRODUCTION
core and the mmf is proportional to winding
Nonlinear properties of circuit elements can
current, the current waveform will be inbe a potential source of abnormalities.
phase with the flux waveform, and both will
Transformer magnetizing inrush current is
be lagging the voltage waveform by 90º. In
an example. When a transformer is initially
an ideal transformer the magnetizing current
connected to a source of AC voltage, there
would rise to approximately twice its normal
may be a substantial surge of current through
peak value as well generating the necessary
the primary winding called inrush current.
mmf to create this higher-than-normal flux.
This is analogous to the inrush current
However, most transformers aren’t designed
exhibited by an electric motor that is started
with enough of margin between normal flux
up by sudden connection to a power source,
peaks and the saturation limits to avoid
although transformer inrush is caused by a
saturating in a condition like this and so the
different phenomenon.
core will almost certainly saturate during
We know that the rate of change of
this first half-cycle of voltage. During
instantaneous flux in a transformer core is
saturation disproportionate amounts of mmf
proportional to the instantaneous voltage
are needed to generate magnetic flux. This
drop across the primary winding or as stated
means that winding current which creates
before, the voltage waveform is the
the mmf to cause flux in the core will
derivative of the flux waveform, and the flux
disproportionately rise to a value easily
waveform is the integral of the voltage
exceeding twice its normal peak. This is the
waveform. In a continuously-operating
mechanism causing inrush current in a
transformer, these two waveforms are phasetransformer primary winding when
shifted by 90º. Since flux (Φ) is proportional
connected to an AC voltage source. As the
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magnitude of the inrush current strongly
depends on the exact time that electrical
connection to the source is made. If the
transformer happens to have some residual
magnetism in its core at the moment of
connection to the source, the inrush could be
even more severe. Because of this
transformer over current protection devices
are usually of “slow-acting” variety so as to
tolerate current surges such as this without
opening the circuit.
The inrush phenomenon was known to
people from years when the transient
behavior of RL circuits was studied. The
studies related to magnetic materials, BH
curves, saturation, etc. enabled scientists to
understand the concept in a better way.
Gaowa Wuyun et. al. in this paper,
introduces the residual flux of transformer
ferromagnetic-core which is not random
when it enters into Power System without
load form last cutting off. Firstly, the
relationship between residual fluxes and the
last exciting current was discussed, then
hysteresis loop was divided into three
antisymmetric sections according to
reversibility of magnetic domains Methods
were proposed to calculate residual flux
approximately section by section based on
the principle of similar-shape and
ferromagnetic characters [1]. Scientists
started modeling of inrush current by
constructing a low frequency model of
transformer. A.M. Miri, et. al. Modeled a
100 MVA transformer and obtained inrush
current in all the three phases [2]. Kunal J
Patel discuss the effects of inrush current in
transformers they describe the fundamental
theory and relevant laws of the transformer
and inrush current. A number of factors
affecting inrush current are discussed. The
inrush current theory and their equation are
derived. The effects of inrush current are
described in brief. The Matlab Sim-Power
system is used for the simulation. The
simulation results compared with each other
and also data available from actual same size
transformer. Finally six solutions to inrush
current mitigation techniques with a
practical low cost answer are provided [3].
John H. Brunk ahnd Klaus J. Frohlich
theoretically proposed controlled switching
as a method to mitigate inrush current in a
single phase transformer by making a
transformer model considering saturation
characteristics of magnetic core and an
inevitable residual flux. They also
introduced the concept of core flux
equalization which means equalization of
flux in all the three limbs of transformer core
when one of the phases is energized. They
calculated the inrush in their model for
simultaneous closing, rapid closing and
delayed closing of circuit breakers [4].
Ramsis S. Girgis et. Al. describe the
characteristic of inrush current of present
design of power transformers. They says that
Accurate calculation of peak and % 2nd
harmonic of inrush current is critical to
appropriate selection of relay protection of a
power transformer. A description is given of
a rigorous calculation of magnitude and
wave-shape of inrush current as a function of
the transformer design parameters as well as
parameters of the system to which the
transformer is connected [5] Hongkui Li. et.
al. shown the analysis of three phase power
transformer winding forces caused by
magnetic inrush and short circuit currents.
These forces are compared with the
corresponding forces due to short-circuit of
the windings. Three-dimensional finite
element computation of three-phase power
transformer is carried out based on the
maximum permissible magnetic inrush
current value where its amplitude is the same
as the rated short-circuit current. To verify
the computation results, they are compared
with those obtained using Ansys software
simulation [6]. Salman Kahrobaee et. al.
worked on the investigation and mitigation
of inrush current in power transformer
during black start of an independent power
producer plant, energy and power
engineering. They describe that when a
transformer is energized by the utility, a
typical inrush current could be as high as ten
times its rated current. This could cause
many problems from mechanical stress on
transformer windings to harmonics injection
and system protection malfunction. There
have been numerous researches focusing on
calculation and mitigation of the transformer
inrush current. With the development of
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smart grid, distributed generation from
independent power pro-ducers (IPPs) is
growing rapidly. They simulate the
simulation model in DIgSILENT Power
Factory software [7]. Mukesh Nagpal et. al.
proposed a technique to mitigate inrush
current of start transformer by introducing a
neutral resistor. They simulated results for
both, simultaneous closing and delayed
closing of circuit breakers [8]. Juei Shyu et.
al. proposed a model to reduce inrush
current of a single-phase transformer by
using voltage series compensation. he used
voltage sag caused by switching to control
the voltage of a compensator [9]. In [10-17]
several worked on sequential energisation of
three phase transformers along with a neutral
resistor. They made a steady state analysis of
transformer with neutral resistor and plotted
the inrush peak for its different values. They
also formulated optimal neutral resistor for
mitigation of inrush current.
2. PROBLEM FORMULATION
The inrush current has already been
described in Chapter 1. This inrush current is
very harmful for transformers. It can burn
the transformer winding due to heating up of
winding. When the transformers starts, high
magnitude harmonics rich current generated
in the transformer, this high current
generated due to high flux in air gap in
transformers. This high current heating up
the winding and the dangerous situation can
be created in the transformers [5].
Figure 1: Current waveform
Figure 1 shows a general waveform with
inrush current magnitude, peak current and
steady state current. At the time of starting
of electrical equipment large current get
generated in the equipment and it is tries to
exceed the peak current. The main reason to
generate the inrush current is flux. When a
electrical equipment is de energized, some
flux remain in the core or air gap of the
equipment and when again energized the
same equipment, the flux trying to reach
beyond the maximum value of 2Φmax, it
becomes constant but current is always
proportional to flux so the current increased
gradually and reaches 5 to 10 times greater
than full load current of equipment [6].
When transformer energized, several
currents flows in transformer which are
shown in figure 2. Current 1 is peak current,
current 2 is large pulse width current and
current 3 is mal functioning current. Peak
current is the current which is maximum
value of current either positive or negative
direction of the transformer. Large pulse
width current has large value of width in
each steps of sinusoidal wave. Mal function
current is generated by inrush phenomena. It
can also call as false function current.
Figure 2: Inrush current waveforms [6]
Figure 3: Flow chart to differentiate the
inrush current
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Figure 3 shown the flow chart of
differentiate inrush current. As the
transformer re energized, current will flow in
the primary core of transformer. The value
of current (magnitude and phase ) is
measured by current transformer , which
discriminate between normal current and
fault current. In next step, preset value
compare the current with calculated value
and 1st and 2nd harmonics are also calculated
in the calculated current. If 1st and 2nd
harmonics are present with large value in the
current, it shows that inrush current is
present and if both harmonics absent which
means there are internal or external faults are
present in the transformer. Both, the
magnitude and presence of harmonics are
decide about the next step to protect the
transformer. If there is inrush current or
external fault present, the transformer do not
trip but if there is internal fault present, the
transformer will trip immediately. For the
next samples, this process repeat again and
again.
3. REDUCTION TECHNIQUES
There are many methods to mitigate inrush
current like injection of resistor in system,
injection of voltage by Pulse Width
Modulation, Point on Wave switching
(POW). This Chapter describes a new
method to mitigate inrush current which
called prefluxing and modeling to mitigate
inrush current with using prefluxing. A filter
is also used in prefluxing device to control
the harmonics in power transformer. The
prefluxing technique is the combination of
POW prefluxing device and filters. In recent
years, various protection systems for
transformers based on the differential
relaying
were
developed.
Various
techniques based on complex circuit or
microcomputers are proposed to distinguish
inrush current fault current. However, the
transformer still must bear with large
electromagnetic stress impact caused but the
inrush current. The main factors affecting
the magnetizing inrush current are POW
voltage at the instant of energization,
magnitude and polarity of residual flux.
Total resistance of the primary winding,
power source inductance, air core
inductance between the energizing winding
and the core, geometry of the transformer
core and the maximum flux carrying
capability of the core material. From past
years many techniques have used to mitigate
inrush current for example point on wave
switching, pre insertion of resistance in
primary of transformer, injection of voltage
in tertiary winding etc.
4.
MITIGATION
OF
INRUSH
CURRENT IN THREE PHASE POWER
TRANSFORMER
USING
PREFLUXING
A MATLAB Simulink model has prepared
for simulation study. Here three phase power
transformers having a rating of 250 MVA,
11/400 KV, 50 Hz, connected to a supply
source as shown in Figure 4. This model
used prefluxing technique to mitigate inrush
current and harmonics. Current and flux
measurement devices are connected whose
results are also shown in next section. The
core is used with specific initial fluxes and
saturation limit. Some amount of flux
provides in each phase to get the value of
inrush current. When the power transformer
energized, the flux of all three phases will
increase and reach till the maximum value of
flux. And after that maximum value of flux
will become saturated and drawn more
inrush current from source, which may be 5
to 10 time greater than rated current. The
main reason of saturation of flux is due to
residual. Residual flux is nothing but it is
some amount of flux which remains in the
core at the time of de energisation of
transformer. Residual flux is depending on
the rating of power transformer and at the
instant
on
which
transformer
is
deenergizing. It will have different value for
different rating transformer. MATLAB
Simulink model shown in figure.
5. SIMULATION RESULTS
Prefluxing technique is used to reduce the
effect of inrush current and harmonics till
99%. The prefluxing technique discussed in
Chapter 4 and the result of transformer after
using prefluxing is shown under:
Mitigated Current: Figure shows the
current after using prefluxing technique on
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transformer. The inrush current goes down
99 % by this technique.
Flux: Flux of all three phases shown in
figure 5 (D) This flux is unsaturated flux.
Figure 5 (A) Mitigated current in phase
A.
Figure 5 (A) shows the mitigated current in
phase A. the magnitude of current is 46 Amp
which is normal for transformer while
without using any technique the current in
phase A was 1700 Amp.
Figure 5 (D) Flux of compensated system
Harmonics: By using prefluxing technique
and filter, the harmonics eliminate from the
system. Figure 5 (E) shows the harmonics in
phase A, phase B and phase C.
Figure 5 (B) Mitigated current in phase
B
Figure 5(B) shows the mitigated
current in phase B the magnitude of current
is 47 Amp This is normal for transformer
while without using any technique, the
current in phase B was 1425 Amp.
Figure 5 (C) Mitigated current in phase
C
Figure 5.(C) shows the mitigated
current in phase C the magnitude of current
is 46 Amp This is normal for transformer
while without using any technique the
current in phase C was 410 Amp.
Figure 5 (E1) Harmonics in phase A
Figure 5 (E1) shows the harmonic in phase
A. Total harmonic distortion (THD) in phase
A is 0.04 %, while THD without using
prefluxing is 25.78%. So this technique
reduces harmonics 99 %. Fundamental
component as figure 5.5 is 0.07 and second
harmonic is 0.028
Figure 5(E2) Harmonics in phase B
Figure 5(E2) shows the harmonic in phase B.
Total harmonic distortion (THD) in phase B
is 0.02 % while THD without using
prefluxing is 39.12 %. So this technique
reduces harmonics 99 %. Fundamental
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component as figure 5.6 is 0.0012 and
second harmonic is 0.014.
Figure 5 (E3) Harmonics in phase C
Figure 5(E3) shows the harmonic in
phase B. Total harmonic distortion (THD) in
phase B is 0.02 % while THD without using
prefluxing is 81.38 %. So this technique
reduces harmonics 99 %. Fundamental
component as figure 5.7 is 0.0016 and
second harmonic is 0.013.
Table 5.1 Comparison between SSSC and
prefluxing technique to mitigate inrush
current
Phas
es
A
B
C
Without using
any mitigation
technique
Curr Harmon
ent
ic
Using SSSC
Curr
ent
Har
mon
ic
190
0
142
5
410
25.78
190
39.12
58
81.38
60
17.2
6
28.6
0
22.6
7
Using
prefluxing
technique
Curre
Har
nt
mon
ic
46
0.04
47
0.02
46
0.02
As shown by table 5.1, prefluxing technique
is far better than SSSC. Prefluxing technique
not only mitigates inrush current in
transformer but also it eliminates harmonics.
SSSC technique can mitigates only 80
percent of inrush current while prefluxing
mitigates 98 percent of inrush and
harmonics. As shown in above table, there is
1900 Amps of inrush current in phase A
which is mitigated by SSSC till 190 Amps
while prefluxing mitigated same current till
46 Amps which is almost negligible. The
same case can be shown in another two
phases, phase B has 1425 Amps current
which mitigated 58 Amps by SSSC and 47
Amps by prefluxing and in phase C,
generated 410 Amps current which is
mitigated till 60 Amps by SSSC and 46
Amps by prefluxing. So the conclusion is
that, prefluxing technique is not only
economic but also it is very efficient for
covering the purpose completely.
6. CONCLUSION
The main purpose of this thesis is to
mitigate the inrush current and harmonics
which is generated in three phase power
transformer. This inrush current is very
harmful for transformer. The effect and
factors of inrush current on power
transformer is also described in this thesis.
In this thesis, we have investigate inrush
current, harmonics, voltage and flux by
using MATLAB®/simulink model and find
the high magnitude starting current and total
harmonics distortion in transformer .
In this thesis, we have introduce a
new technology to reduce the inrush current
and harmonics that is called prefluxing
technology. This prefluxing is a device
which is made by charged capacitor and
converter. There are many methods to
reduce high starting current and harmonics
but all methods reduce only 70% to 80 %
starting current and harmonics but in this
research, we have reduce 95 % of starting
current and harmonics.
7. FUTURE SCOPE
The proposed prefluxing device can
replace filter popularly used for harmonics
mitigation. It reduces the cost of the system
satisfactory extent. This prefluxing device is
cheaper in comparison to power electronics
compensation devices like SSSC, DVR,
UPFC etc to improve stability of system.
REFERENCES
1. Gaowa Wuyun ,Po Li and Dichen Liu,
“Phase Control to Eliminate Inrush Current
of Single-phase Transformer by Using
Approximate Calculation of Residual flux”
IEEE 2006
2. A.M. Miri, C Muller, C Sihler, “Modelling
of Power Transformers by a detailed
magnetic equivalent circuit” Researchgate
publication 228429082.
3. Kunal J Patel, “Effect of Transformer Inrush
Current” thesis, University of Southen
Queen land , PP 2539.
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4. John H. Brunke, Klaus J. Fröhlich, Senior
Member,
IEEE,
“Elimination
of
Transformer Inrush Currentsby Controlled
Switching—Part
II:
Theoretical
Considerations” IEEE, vol. 16, April2001.
5. Ramsis S. Girgis, Ed G. Tenyenhuis,
Member, IEEE, “Characteristics of Inrush
Current of Present Designs of Power
Transformers” IEEE, 2007.
6. Hongkui Li1, Yan Li, Xi Sun,
DongxuLi,Youteng Jing, “Analysis of
ThreePhase Power Transformer Windings
Forces Caused by Magnetic Inrush and
ShortCircuit Currents” IEEE, Sept.2009.
7. Salman Kahrobaee, Marcelo C. Algrain,
SohrabAsgarpoor,
“Investigation
and
Mitigation of Transformer Inrush Current
during Black Start of an Independent Power
Producer Plant, Energy and Power
Engineering, 2013
8. Mukesh Nagpal, Terrence G. Martinich, Ali
Moshref, Kip Morison, and P. Kundur,
“Assessing and Limiting Impact of
Transformer Inrush Current on Power
Quality” IEEE transaction, vol. 21, April
2006.
9. Juei Lung Shyu, “A Novel Control Strategy
of Reduce Transformer Inrush Current by
Series Compensation” IEEE2005
10. Abbas Ketabi, Ali Reza HadidiZavareh,
“New Method for Inrush Current Mitigation
Using
Series
VoltageSource
PWM
Converter for Three Phase Transformer”
IEEE2011.
11. L.Jebaraj and N. Muralikrishnan, “DE
Algorithm based Comparison between Two
Different Combinations of FACTS Devices
under Single Line Outage Contingency
Conditions” IEEE 2012.
12. Saidi Amara and Hadj Abdullah Hsan, “
Power System Stability improvement by
FACTS device: A comparison between
STATCOM, SSSC and UPFC” IEEE 2012.
13. Sandeep Tripathi, R.K Tripathi, “ Voltage
Stability Improvement in Power System
using FACTS Controller: States of
ArtsReview” IEEE2010.
14. Li Wang, Quang Son Vo, “ Power Flow
Control and Stability Improvement of
Connecting an Offshore Wind Farm to a One
–Machine Infinite bus System Using a Static
Synchronous Series Compensator” IEEE
2013.
15. Alex Reis, Jose C. de Oleveira, Roberto
Apolonio, Herivelto S. Bronzeado, “ A
Controlled Switching methodology for
Transformer inrush Current Elimination:
Theory and Expermrimental Validation”
IEEE Oct2011
16. Douglas I. Taylor, Joseph D. Law, Brian K.
Johnson
and
Normann
Fischer,
“SinglePhase Transformer Inrush Current
Reduction Using Prefluxing” IEEE, January
2012.
17. V. Oiring de Castro Cezar, LL. Rouve, JL.
Coulomb, FX. Zgainski, O. Chadebec, and
B. Caillault, “Elimination of inrush current
using a new prefluxing method. Application
to a single phase transformer” IEEE2014
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Analysis of Solar Thermal Cooling System Using TRANSOL
Khagendra Kumar Upman*, Deepak Goyal, Dhawal Vyas, Navneet Sharma B.L.Gupta*
Government Engineering College Bharatpur Rajasthan.
*Corresponding Author email: kha16gietupman@gmail.com,blgbharatpur@gmail.com
Abstract:
This paper covers the performance analysis of solar thermal cooling system for a computer
laboratory situated in Government Engineering College Bharatpur using Flat Plate Collector,
Evacuated Tube Collector and Compound Parabolic Collector. The computer lab has the floor and
roof area 198.55 m2. The peak cooling load is calculated and it is 34.94 kW, accordingly 10TR
vapor absorption cooling system was adopted. The 10 TR vapour absorption system was operated
by a field of collector area varying from 80-120 m2..The other parameters like hot storage tank, cold
storage tank, pump, cooling tower etc are used. The simulation was carried out on TRANSOL
Program for Bharatpur city situated in east of Rajasthan (INDIA). It can be conclude that solar
thermal cooling system is technically feasible because it offers good solar fraction in the range of
0.52-0.75. The primary energy savings reaches up to 52%.
Keywords—Solar Thermal System, TRANSOL, Solar Fraction, Primary Energy ,
1.Introduction
Because of global warming, increased energy
need, limited resources and environmental
pollution there is dire need for development of
such technologies that can offer decrease in
energy consumption, peak electrical demand,
and energy costs without lowering the desired
level of comfort. That can also significantly
reduce the emission of CO2 because buildings
use around 50% of the total energy
consumption in developed countries. In place of
the use of electricity in conventional cooling
systems, solar thermal cooling systems use
solar heat to produce refrigerating effect. In
such systems the phenomenon of sorption: the
process by absorption liquid-gas and the
process by adsorption solid gas are utilized to
produce the refrigeration effect.
A solar electric refrigeration system consists
mainly of photovoltaic panels and an electric
refrigeration
device
based
on
vapor
compression system. Photovoltaic panels
consist of solar cells which are basically made
of semiconductor materials that convert the
incident solar radiation into direct current. This
direct current may be directly used to drive the
DC compressor or may be converted into AC to
drive the conventionally used AC compressor.
Using solar panels for refrigeration has many
advantages. They are simple, compact in size,
high power to weight ratio and have no moving
parts. In this system solar panel drive the DC
motor of the compressor for producing the
cooling effect in the evaporator by absorbing
Fig. 1 Vapour Absorption System
heat and rejecting heat to the ambient by the
condenser. In the vapour absorption systems, a
pair of substances having the strong affinity to
form a solution is utilized. Among the pair of
substances, the substance having lower boiling
temperature is called refrigerant and the other is
called absorbent. Solar thermal collector is used
to supply low grade heat input in the generator.
Cooling is produced in the evaporator and heat
is rejected from the condenser and the absorber.
H2O-LiBr and NH3-H2O are the two major
working pairs used in the absorption system. In
the water lithium bromide pair H2O works as
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the refrigerant and other is the absorbent while
in the ammonia H2O pair ammonia works as the
refrigerant and water is the absorbent.
Currently, various absorption machines with
COPs ranging from 0.3 to 1.2 are available. For
double-effect LiBr-water chillers with COPs
around 1.2 are available for air conditioning
which use solar collector capable of working at
150°C but the costs of these systems are high.
Less expansive collectors can be used for single
effect LiBr-water absorption machine.
2. Methodology Adopted:
The whole work is divided into three phases.
First phase is related to defining a building for
carrying out the analysis. The building has a
floor area of 198.55 square meters. Parameters
such as construction detail, occupancy, lighting
load, ventilation, infiltration are defined as per
utilization of existing building of computer lab
situated at Govt. engineering college Bharatpur.
The cooling load of the building is determined
by using calculation for sensible cooling load
and latent cooling load. Details of heat gain, with
respect to source, such as wall conduction,
reflection, direct solar heat gain etc are taken.
In the second phase according to the cooling load
of the building the component sizing for solar
thermal cooling system is carried out. The
building simulation of solar thermal cooling
system is done in the program TRANSOL 3.1
(software for simulating thermal solar cooling
systems) by taking suitable component and their
size. Based on the results given by the
program’s key parameters, solar fraction,
primary energy savings, electrical (Grid) COP
and paybacks are calculated for solar thermal
cooling systems. Finally in the last phase
conclusion is made on the behalf of paybacks
whether the system was adopted for the existing
building or not.
Laboratory is scheduled from 9 AM to 6 PM
from Monday to Saturday and Sunday is
holiday.
Total room sensible heat = 1.115 x total
sensible heat gain from all sources = 24.93 kW
Total room latent heat = 1.06 x total latent heat
gain from all sources = 10.01 kW
Therefore, total cooling load = 10.01 + 24.93 =
34.94 kW.
3 Modelling and Simulation
In the present work modelling and simulation of
small scale solar cooling systems is carried out
using TRANSOL program. The program
TRANSOL EDU 3.1 is used for the simulation
of a solar thermal cooling system. The
simulation is carried out for a computer lab
used in day time only and which is considered
to be in situated at Govt. engineering college
Bharatpur in India an Asian country.
The solar analyzed thermal cooling system is
composed of a solar collector field (Solar
collector), hot storage tank (HST), cold storage
tank (CST) and vapour absorption chiller
(VAC). Three different types of collectors are
considered in this study flat plate, evacuated
tube and compound parabolic. The solar
collector captures the energy from the sun and
supplies energy to a hot storage tank through an
external heat exchanger.
A 35 kW capacity vapour absorption chiller
(VAC) is selected which have the COP 0.7 and
pump power consumption of 210W. A cooling
tower of 90 kW capacities is selected because
the generator capacity of VAC is 50 kW and
heat rejection in the condenser is 90 kW.
A hot storage tank of 5000 litres and a cold
storage tank of 1000 litres are used. The wide
variance of collector area 80-120 m2 is taken
with an interval of 10 m2.
Two pumps are used in the solar collector loop,
one is to circulate hot working fluid from solar
collector to heat exchanger, and another to
circulate fluid between heat exchanger and hot
storage tank. These pumps (P1, P2) are known
as primary and secondary pump respectively
and operated by control strategy depending on
solar radiation intensity. The flow rate of pump
is constant. The system stops the pumps if the
temperature in the hot storage tank exceeds the
maximum security value.
A vapour absorption machine (VAM) is directly
connected to the hot storage tank, this machine
is turned on when cooling is required and the
temperature of the solar tank is over a set point
temperature. The heat coming from the
absorber and condenser is released by cooling
tower controlled by a variable frequency drive
that increases energy efficiency and reduces
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electrical energy consumption. The cold water
coming out from the evaporator of vapour
absorption machine is stored in the cold storage
tank (CST).
An electrical operated compression cooling
machine is used as a backup in order to cover
complete cooling demand of the building. This
compression based cooling machine is operated
only when the cooling demand is in building
and the temperature of the cold storage tank is
below than the specified set point temperature.
Fig. 7 shows that comparison of solar fraction
for different three types of collector i.e
FPC/ETC/CPC and shows that the using CPC
solar fraction is highest.
Fig. 4 Solar Fraction for FPC
Fig. 2 Solar Thermal Cooling System
4. Simulation Results:
In this paper we have analyzed and compared
performance of solar thermal cooling system
using 3 types of solar collector. These collectors
are: Flat plate collector (FPC), Evacuated tube
collector (ETC) and Compound parabolic
collector (CPC). Simulation is performed to
find out some performance metrics like Annual
net collector efficiency, solar fraction and
Specific net collector output for each collector.
Simulation results are as follows:
Fig. 3 Net Collector Efficiency for FPC
Fig. 5 Solar Fraction for ETC
Fig. 6 Solar Fraction for CPC
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Fig. 7 Comparison of Solar fraction for each
collector
5. Conclusion:
Referances:
1.
ASHRAE, Handbook of fundamentals,
1997,2009.
2.
Climatech Aircon Engineering Pvt. Ltd.
Jaipur Jaipur. 2014 “Quotation for
supplying the packaged air conditioner
and pumps” at Government Engineering
College Bharatpur (Raj.) India.
3.
Duffie J.A., Backman W.A. 2006 “Solar
engineering of thermal process” Third
edition Published by John Wiley & Sons
Inc, Hobokan New Jersey.
4.
Eicker U., Colmenar-Santos A., Teran L.,
Cotrado M. 2014 “Economic evaluation
of solar thermal and photovoltaic cooling
systems through simulation in different
climatic conditions: An analysis in three
different cities in Europe” Energy and
Buildings, Vol. 70, pp. 207-223.
5.
TRANSOL
http://aiguasol.coop/en/transol-solarthermal-energy software.
6.
Tsoutsos T., Aloumpi E., Gkouskos Z.,
Karagiorgas M. 2010 “Design of a solar
This study covers the performance analysis of
solar thermal cooling system for a computer lab
situated in government engineering college
Bharatpur using FPC, ETC and CPC. The
computer lab has the area 198.55 m2 .The peak
cooling load is 34.94 kW accordingly 10TR
vapour absorption cooling system was adopted.
The 10 TR vapour absorption system was
operated by a field of collector area varying
from 80-120 m2.. The solar fraction is highest
for the CPC type collector and lowest for the
FPC. The highest solar fraction has been
observed as 0.63, 0.72, 0.73 for FPC/ETC/CPC
for the collector area range in 80-120 m2. At
high collector area the collected heat is
increased in all the type of collector but in the
case of ETC and CPC the heat losses also
increase.
absorption cooling system in a Greek
hospital” Energy and Building, Vol.42,
pp. 265-272.
7.
Gupta, B.L., 2015. “Technoeconomic
comparision of small scale solar thermal
and photovoltaic cooling system” Ph.D
thesis MNIT Jaipur.
8.
Henning H.M. 2007 “Solar assisted air
conditioning of buildings – an overview”
Applied Thermal Engineering, Vol. 27,
pp. 1734–1749.
9.
Kim D.S., Infante Ferreira C.A. 2008
“Solar refrigeration options – a state-ofthe-art review” International Journal of
Refrigeration Vol. 31, pp. 3–15.
10. TRANSOL
http://aiguasol.coop/en/transol-solarthermal-energy software.
11. Tsoutsos T., Aloumpi E., Gkouskos Z.,
Karagiorgas M. 2010 “Design of a solar
absorption cooling system in a Greek
hospital” Energy and Building, Vol.42,
pp. 265-272.
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Analysis and Modeling of AC-DC Buck Converter Using PFC Control
Technique
Gaurav Vijay1,*, D.K.Palwalia2
Department of Electrical Engineering, Rajasthan Technical University Kota, India
Corresponding Author: gvijay.mtech@rtu.ac.in
Abstract
This paper presents non-isolated single-phase AC-DC buck converter which are used for
improving power quality at AC mains input source which improves power factor. The AC-DC
converters convert to regulate supply process which injects harmonics distortion and waveform at
input AC source. This AC-DC buck converter are used with PFC based technique. This technique
reduces the input current harmonics and improves power quality. The main objective of this paper is
to obtain a unity power factor and a constant DC output voltage. Here, a source conditioning based
design of these converter is demonstrated and a comparison of with and without source conditioning
based converter is shown. The operation and simulation results obtained by the proposed source
conditioning scheme, with the help of MATLAB/Simulink that verifies the design.
Keywords—Buck Converter; Proportional Integral(PI); Without PFC Technique; With PFC
Technique.
INTRODUCTION
Now a day, it is generally the AC-DC
converters are widely used in low power
applications. The power electronics application
is to convert the electric power available from a
power source into the form which is best suited
for user loads. Some types of power converters
are required to interface between power source
and load to achieve this objective. Hence, the
converters may be AC-DC, DC-DC, AC-AC,
DC-AC [1], with or without transformer
isolation depending on the load. The
conventional power factor correction(PFC)
converters can achieve close to unity power
factor, low total harmonic distortion(THD) and
constant output voltage.
In this block diagram single phase AC
source is feed to the diode bridge rectifier. It is
convert AC power into DC power but it is
unregulated power. This unregulated power is
to convert regulated DC power by using control
DC-DC converter[2-4].
I.
Single Phase
AC Source
Uncontrolled
Diode
Rectifier
Filter
Capacitor
DC
(unregulated)
DC-DC
Converter
DC
(unregulated)
Load
DC
(regulated)
Controller
Fig. 1. Block diagram of AC-DC Converter
DC-DC converters are the electronic
devices used to change DC electrical voltage
efficiently from one level to another. These
converters required because unlike AC, DC
cannot be simply stepped up or down using a
transformer. In many ways, a DC-DC converter
is the DC equivalent of a transformer. These
converters are widely applicable in different
areas like, where 24V to be stepped down from
a truck battery to 12V DC to operate a radio,
transceiver or mobile phone. The DC-DC
converter includes various topologies such as
Buck converter, Boost converter, BuckBoost[5] and Cuk converter. To improve the
power factor in the buck converter topology.
There are two types of PFC methods as passive
method and active method. The active PFC
method is used recently in most of the electronic
components. Power conditioning techniques
like PFC and harmonic filtration is used to
reduce in the circuit THD[6].
The AC-DC buck converter is probable by
using typically diode bridge rectifier(DBR)
circuit[7-9]. The use of diode rises the
nonlinearity of the system as the diode is
considered as nonlinear load. Non-linear loads
generally do not cause reactive power to flow at
the fundamental line frequency. They can,
however, draw higher RMS currents and hence
add to distribution system losses for a given
load. The non-linear nature of these loads then
draws non-pure sine wave currents thus causing
harmonics of the fundamental current to be
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present. Since harmonic distortion is caused by
freewheeling diode. The switching network
non- linear elements connected to the power
made up of the transistor and the diode ‘chops’
system, any device that has non-linear
the DC input voltage VDC and therefore the
characteristics will cause harmonic distortion.
converter is known as ‘chopper’, which
The power quality issue will increase[10-12].
produces a decrease average output voltage.
This converter is used to convert the input
The switching frequency fs =
and the duty
side AC supply to a regulated DC output. This
cycle is –
converter produces supply pollution and makes
𝐷=
=
= 𝑓𝑡
(1)
source current nonlinear as, the source current
(
)
L
in this converter infects the input current
S
harmonics, ripple and THD[13-15]. The rapid
increase in deployment of such converter
expressively increase the problem. In order to
+
achieve the conversion of AC-DC, two stages
VDC
+
C
RL
DM
are used. First stage is a DBR which provide
Vo
AC-DC conversion and the second is a DC-DC
converter[16-18]. This complete system
through its operation gives desired output but
along with that, the input side line current
harmonics, ripple and THD are high.
Fig. 2. Equivalent Circuit for PWM buck
In these source current harmonics, ripple is
Converter
condensed by PFC control technique[19-22].
B.
Design Oriented Analysis of Buck Converter
This control technique requires two control
The calculation of buck converter where
loops which are essential with the outer loop
V
=
24V, Vo = 12V, Io = 0.8616A, RL = 13.9𝛺,
DC
named as voltage loop controller and inner loop
ripple
voltage Vr (1% of Vo) = 0.12V, ripple
is PWM current loop controller. Some other
current ∆iL = 1.72A, switching frequency fs =
word control technique is used to control
100kHz. and the other parameter is listed Table
inductor current include peak current control,
I is given as follows –
average current control, hysteresis control and
border line control[23-26]. Normally, direct
Duty ratio:
current output voltage of the converters in the
𝐷=
(2)
system output is used as feedback loop as outer
closed loop control and different control
Output power:
systems
such
as
proportional-integral
𝑃 =𝑉 𝐼
(3)
Inductor L:
controller,
proportional-integral-derivative
(
)
controller, sliding-mode-control are providing
𝐿=
(4)
to fast dynamic response[27-30].
Capacitor C:
II. SYSTEM CONFIGURATION
C=
(5)
A. Analysis of PWM Buck Converter
Ripple Current ∆iL:
A buck converter is a step-down converter
(
)
where the output DC voltage which is lower
∆𝑖 =
(6)
than the input voltage. It has the advantages of
ESR rC:
simplicity and low cost. A PWM DC-DC buck
𝑟 =
(7)
∆
converter is a combination of diode, inductor
TABLE I.
PARAMETER FOR BUCK CONVERTER
and MOSFET switch. Here MOSFET works as
TOPOLOGY
a switch and it’s on and off control depends on
Parameter
Values
PWM signal. Filtering capacitor with equivalent
Input Voltage VDC
24 V
series resistance(ESR) is also required to the
Output Voltage VO
12 V
output of the converter to decrease output
voltage ripple. The diode DM is known as
Duty Ratio D
0.5
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Parameter
Values
Input Voltage VDC
24 V
Output Voltage VO
12 V
Inductor L
34.75 µH
Capacitor C
35.83 µF
ESR rc
69.76 m𝛺
Output Power PO
10.3 W
III. PROPORTIONAL-INTEGRAL CONTROL
STRATEGY
In order to control and regulate the output
DC voltage at desired level, against input
voltage and load variation, a fast and reliable
closed loop controller is essential to sustain the
steady as well as dynamic performance of
system. The voltage error Ve is calculated from
the difference between the reference voltage V*
and the output DC voltage Vo as –
𝑉 = 𝑉∗ − 𝑉
(8)
V*
-
Integral Gain
Limited Integrator
+
∑
+
I
Ve
∑
+
KI
based AC-DC buck converter only one control
loop which is voltage loop like PI controller is
required. In this PI controller the output voltage
is taken as a reference signal. This reference
signal is compared with a constant to generate
voltage error signal, this voltage signal is feed
to PI controller and output of this controller is
compared with triangular pulse. The output
signal of relational operator is PWM signal that
is feed to the switch.
L
S
D1
D3
C
DM
VS
D4
RL
D2
PWM
Controller
PI
Controller
Ve
+
V*o
Fig. 4. AC-DC without PFC based Buck
Converter
Vo
KP
Proportional Gain
Fig. 3. Schematic of Proportional-Integral(PI)
Controller
The output DC voltage Vo is fed to error
amplifier to produce error signal Ve
proportional to the subtracted value of Vo from
reference set point value V*. The error signal Ve
is feed to PI controller.
The transfer function of PI controller is as –
𝑇𝐹(𝑠) = 𝐾 +
(9)
IV. MODES OF OPERATION AND SIMULATION
RESULTS
A. Without PFC Based Buck Converter
In AC-DC buck converter without power
factor correction technique, only one control
loop is required. The single phase without PFC
based AC-DC diode bridge rectifier is shown in
Fig.4. that converts into regulated DC supply by
using DC-DC buck converter. Without PFC
Fig. 5. Simulation results of input, output
voltage and input current waveforms without
PFC based Buck converter
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Vo
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Fig. 6. FFT analysis of without PFC based Buck
converter
Fig. 8. Simulation results of input, output
voltage and input current waveforms with PFC
based Buck converter
In order to achieve the conversion of AC-DC, a
DBR is used which provides desired DC output.
The input line current harmonics are analyzed
using FFT tool and the total harmonic distortion
is shown in Fig. 6. The THD in input side line
current is 46.71% which is quite high and power
factor is 0.63.
B. With PFC Based Buck Converter
The single-phase AC-DC diode bridge rectifier
with PFC based buck converter is shown in
Fig.7. With PFC based AC-DC buck converter,
there are two control loops which are essential
with the outer loop named as voltage loop
controller.
L
S
D1
In voltage loop controller the voltage error
signal is processed through the PI controller to
get desired control signal. The voltage error
signal is generated by output voltage and
reference voltage. This PI controller signal is
product of the unit template of AC supply
voltage and the product signal is compared by
actual DC current signal. The compared signal
is amplified by gain and compared with
triangular pulse and the output signal of
relational operator is PWM signal that is feed to
the switch. The inner loop known as PWM
current loop controller.
Idc
D3
+
DM
VS
C
RL
Vo
-
D4 D2
VS
Ref.
Current
Generator
I*dc
+
PWM
Controller
PI
Controller
Ve
+
V*o
Fig. 7. AC-DC with PFC based Buck
Converter
Fig. 9. FFT analysis of with PFC based Buck
converter
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The source current as shown in Fig. 8. is
analyzed for harmonics using FFT tool. The
FFT analysis of source current as depicted in
Fig. 9. demonstrates that the THD in case of
PFC based buck converter which is reduced to
9.16%. The input voltage and current
waveforms are in same phase that shows
improved power factor is 0.98 and the
comparison of with and without PFC Controller
can be listed in Table II.
TABLE II.
COMPARISON OF WITH AND
WITHOUT PFC CONTROLLER MODE
Modes of Operation
Paramet
Without PFC
With PFC
er
Controller
Controller
% THD
46.71
9.16
Power
0.63
0.98
Factor
V. CONCLUSION
This
paper
describes
power
quality
improvement of AC-DC buck converter using
PFC based technique. The power quality issue
not only refers to the good quality of power but
also to the input parameters which affect the
output of the system. To improve the source
current characteristics, a conditioning technique
is required. Two kinds of control loop are used
voltage loop control and PWM current loop
control. The source conditioning scheme is
simulated for buck converter. The simulation
results show that, with the proposed source
conditioning method the THD is reduced to
9.16% and this decrease in the harmonic content
shows that the PFC based buck converter is
working efficiently and also makes the input
voltage and current waveforms are in same
phase that shows power factor is improved to
0.98 which is useful to increase the efficiency of
the system.
[3]
[4]
[5]
[6]
[7]
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Architectural and Technical Approach for Self-Sustainable Building
Kapil vyas1, Dilip Sharma2, Shivlal3
Student, Civil Engineering Department, GEC Banswara.
2,3 Assistant Professor, Civil Engineering Department, GEC Banswara.
3 Principal, GEC Banswara
Corresponding Author: kapil.vyas28@yahoo.com, dilip17714@gmail.com
1 U.G.
Abstract
Growth of population and demand in energy has leaded us to create and find new ways to quench our
thirst for energy. By giving the solutions for energy demand the environment must not be on stake,
fitting in architecture and building design to create a more greener and eco-friendlier as well as
sustainable design to reduce the carbon per capita. Filling the blank new spaces created in the
sustainable architecture has opened the ideas of eco-friendly and sustainable designs to carry our
increasing demand of energy and comfort. Using sustainable architecture and technologies, and
introducing the technology that uses the renewable source of energy and not depending on fossil fuels.
Building architecture so as it can be self-sustained by its own renewable energy source.
Keywords: Renewable Energy, Self-Sustainable Building, Solar, Wind, Biomass, Architectural
Orientation.
1.
Introduction
Green buildings are becoming increasingly
common for both residential and commercial
structures. The high demand for green design
integrates world consciousness for the
environment and sustainability. In many cases
green structures may provide a lower lifetime
cost alternative to conventional building
methods, but has a higher sustainability future
if developed correctly and efficiently.
Although green technology is more expensive
than traditional technologies, it has the
potential to have a shorter payback period due
to significantly reduced utility bills. With the
current economic condition, cost-effective
designs will certainly drive the market
forward. The idea of green design is still a new
concept. Therefore, the definition of what is,
and what is not green has sometimes been
confusing.
2.
Previous work study
Shiv Lal et al. have studied that the residential
and commercial buildings demand increases
with rapidly growing population. It leads to the
vertical growth of the buildings and needs
proper ventilation and day-lighting. The
natural air ventilation system is not
significantly works in conventional structure,
so fans and air conditioners are mandatory to
meet the proper ventilation and space
conditioning. Globally building sector
consumed largest energy and utmost
consumed in heating, ventilation and space
conditioning. This load can be reduced by
application of solar chimney and integrated
approaches in buildings for heating, ventilation
and space conditioning. They concluded that it
is a sustainable approach for these applications
in buildings. The authors are reviewed the
concept, various method of evaluation,
modelings and performance of solar chimney
variables, applications and integrated
approaches. Peter et al. studied in their paper
a
conceptual
framework
aimed
at
implementing sustainability principles in the
building industry. The proposed framework
based on the sustainable triple bottom line
principle, includes resource conservation, cost
efficiency and design for human adaptation.
Following a thorough literature review, each
principle involving strategies and methods to
be applied during the life cycle of building
projects is explained and a few case studies are
presented for clarity on the methods. The
framework will allow design teams to have an
appropriate balance between economic, social
and environmental issues, changing the way
construction practitioners think about the
information they use when assessing building
projects, thereby facilitating the sustainability
of building industry. Grierson and Moultrie
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worked in their research that the paradigm shift
for sustainable buildings requires a
transformation of the architectural design
process. This paper examines how
sustainability is embedded into design
methodology and mapped onto, or has
transformed, the design process. Interviews
with a sample of Scottish architectural and
multi- disciplinary practices were undertaken
to explore the common approaches and
barriers to sustainable design. Case study
methodology was also employed to consider
exemplar buildings and the value of postoccupancy evaluation is discussed. Within the
context of the global environmental
perspective, UK and Scottish legislation,
sustainable principles and blueprints, a process
model is developed to provide a framework for
discussion and review. The first creative step
is given as an alignment of practice ethos with
established architectural philosophies and
principles, from across the sustain ability
spectrum, to move towards at ypology of
sustain able building design.
3. The concept of “green”
3.1 Overview of “Green Concept” in
Building Design
There are large amounts of materials used and
energy consumed during the construction and
operation of an average building. The world’s
population has grown exponentially since the
Second World War, and there is currently
pressure on available land and natural
resources. As a society, we will eventually be
faced with the depletion of our most widely
used source of energy, the non- renewable
fossil fuels. There are many ways in which
these organizations are taking steps to reduce
consumption such as developing new types of
vehicles, energy sources, recycled materials,
and designing environmentally friendly
buildings. These environmentally friendly
buildings are also known as “green” buildings.
Example of Existing Green Building
To illustrate the benefits of integrating green
concepts in building design, construction and
operation, a few examples of green buildings
are provided. These examples also help to
answer the question “what is a green
building?”
The Chicago Centre For Green Technology
(CCGT), Chicago, U.S.A.
In 1999 the Chicago Department of
Environment embarked on an ambitious
project known as The Chicago Centre for
Green Technology (CCGT). The Department
gathered a team of architects and engineers
who produced the final designs and oversaw
the construction of a building that would serve
as an example for companies and 7
homeowners all over North America.An
amount of $5.4 million was spent renovating
an existing two-storey, 40 000 ft2 building,
that was to be converted into a green building.
The project team incorporated many of the
most advanced green technologies available at
the time in the design of the CCGT. The idea
was to design a building that would reduce the
demand on natural resources and energy while
decreasing the production of pollution and
waste. The building was to do this without
forcing occupants to change their habits
drastically. The teams design focuses on four
major areas: lighting, water, earth, and air. The
following is a brief summary of the
compilation of green technologies used in
Chicago.
Lighting
Purpose: to reduce fossil fuel emissions
released when electricity is produced.
CCGT design includes:
Photovoltaic cells.
Passive light designs including a
greenhouse with heat absorbing tiles and
skylights.
Smart lighting, which adjusts the electrical
lights according to the available natural
light,
thus
lowering
electricity
requirements.
Motion-sensitive lights that turn themselves
off when the room is empty.
Water
Purpose: To reduce pollution due to storm
water runoff water and to reduce the demand
on the municipal sewer system.
CCGT design includes:
Green roof (with succulent plant stores
water in its roots and leaves and therefore
does not need to be watered during drought)
Cisterns (holding tanks used to collect rain
water)
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Disconnected downspouts (drain to soil not
sewer)
Bio swales (ditches with water-loving
plants which filter pollutants)
Earth
Purpose: To reduce the demand on natural
resources provided by such as oil, wood, and
minerals.
CCGT Design includes:
Promotion of alternate forms of
transportation by providing bike racks,
showers, electrical outlets in the parking lot
for electric cars, and close to major bus
routes.
Demolition waste was recycled when
possible.
Use of recycled materials in the furnishings
in the building.
Air
Purpose: Reduce air pollution and the need for
heating and cooling using non-renewable
resources.
CCGT design includes:
A ground source heat pump and pipe system
that carries a (non-toxic) liquid similar to
antifreeze through a series of looped pipes
200 feet (61 m) below ground level. The
liquid is used to regulate the temperature in
the building.
Highly effective insulation, including the
green roof, that lowers heating and cooling
costs. Use of natural gas to heat the building
Use of local materials in the construction
and operation of the building. This reduces
pollution related to transportation and helps
the local economy.
Use of less harmful chemical products both
for the construction and for the maintenance
of the building.
The green roof atmospheric carbon dioxide
to oxygen through the natural process
(photosynthesis) of the plant life. The roof
also absorbs rainwater and thus reduces the
amount of water released into the city’s
sewer system.
LEED and C2000 Rating systems
LEED Accreditation
In the United States the most prominent green
building accreditation program is the
Leadership in Energy and Environmental
Design (LEED) rating system.
This is a program defining and rating green
buildings. A Canadian equivalent rating
system is currently under development.
It is expected to focus on the same major areas
that the LEED rating system does.
These areas are:
Sustainable Site Planning
Safeguarding Water and Water
Efficiency
Energy Efficiency and Renewable
Energy
Conservation of Materials and
Resources
Indoor Environmental Quality
The LEED rating system awards points for
how a building’s design deals with specific
solutions for the above-mentioned issues.
The United States Green Building Council
(USGBC) uses the LEED checklist to rate a
building. Depending on the total points
achieved for solutions related to the above
areas, a rating for the building is awarded as
follows:
Certified
26-32 points
Silver
33-38 points
Gold
39-51 points
Platinum
52-60 points
Benefits
The benefits of receiving a rating from LEED
include increased publicity and promotion of
high quality design. The rating also gives
designers’ a method of comparing new designs
to old designs in order to determine their
success.
Drawback
Application for a LEED assessment costs the
builder extra money and it does not change the
building once it is built.
4. Self sustainable technologies
4.1 Smart Lighting/ Power Saving
Electronics
Simplest way to reduce energy is by using
power saving electronics and smart lightings.
These devices are designed to turn off when
not in use. Smart lights contain photo sensors
that read how much natural light is entering in
the building and dim electric lights when there
is enough natural light. Sometime smart lights
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are equipped with motion detection sensors so
as to automatically shut off the lights when no
one is in the room. The major benefit of smart
lighting and power saving electronics is that
they reduce energy consumption. The
reduction in energy implies reduced electricity
costs.
4.2 Solar Water Heating
Solar water heating panels are a system of uses
glazed collectors that uses the sun's energy
rather than electricity or gas to heat water. A
solar water heater uses glazed collectors that
are mounted on roof and is connected to
storage tank. Fluid is pumped to the glazed
collectors where it is warmed by the solar
energy, and returned to a heat exchanger where
heat from the fluid is used to heat the water.
The water is then collected in an insulated
water storage tank so as the water can be used
when the sun is not shining. A typical system
will provide 50% to 75% of the water-heating
load.
Fig. 1: Solar Water Heating
4.3 Wind Turbine
Fig. 2: Wind Turbine
Wind turbines are powered by the wind to
produce energy. They do not use up natural
resources and do not produce greenhouse
gases. They are an efficient, clean way to
produce energy. Wind turbines are relatively
low-cost. A 50-kW turbine will be enough to
satisfy the daily energy need of a house.
4.4 Solar Panels
Every building whether home, industry,
institution or commercial establishment can
generate some solar power by installing PV
panels on the roof top. Sometimes this can be
a BIPV (building integrated).
Fig. 3 : Solar Panels
4.5 Urban Bio Gas Plant
Due to scarcity of petroleum and coal it
threatens supply of fuel throughout the world
also problem of their combustion leads to
research in different corners to get access the
new sources of energy, like renewable energy
resources. Solar energy, wind energy, different
thermal and hydro sources of energy, biogas
are all renewable energy resources. But, biogas
is distinct from other renewable energies
because of its characteristics of using,
controlling and collecting organic wastes and
at the same time producing fertilizer and water
for use in agricultural irrigation. Biogas does
not have any geographical limitations nor does
it require advanced technology for producing
energy, also it is very simple to use and apply.
Deforestation is a very big problem in
developing countries like India, most of the
part depends on charcoal and fuel-wood for
fuel supply which requires cutting of forest.
Also, due to deforestation It leads to decrease
the fertility of land by soil erosion. Use of
dung, firewood as energy is also harmful for
the health of the masses due to the smoke
arising from them causing air pollution. We
need an ecofriendly substitute for energy.
Kitchen waste is organic material having the
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December
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high calorific value and nutritive value to
microbes, that’s why efficiency of methane
production can be increased by several orders
of magnitude as said earlier. It means higher
efficiency and size of reactor and cost of
biogas production is reduced. Also, in most of
cities and places, kitchen waste is disposed in
landfill or discarded which causes the public
health hazards and diseases like malaria,
cholera, typhoid. Inadequate management of
wastes like uncontrolled dumping bears
several adverse consequences. It not only leads
to polluting surface and groundwater through
leachate and further promotes the breeding of
flies, mosquitoes, rats and other disease
bearing vectors. Also, it emits unpleasant
odour & methane which is a major greenhouse
gas contributing to global warming. Mankind
can tackle this problem(threat) successfully
with the help of methane, however till now we
have not been benefited, because of ignorance
of basic sciences – like output of work is
dependent on energy available for doing that
work.
Fig. 4: Urban Bio Gas Plant
5.
CONCLUSION
The motivation for this project stems from
recent green trends. Green technologies are
rapidly developing and readily available.
Throughout each step of the design, the
project focused on green alternatives to
traditional construction practice.
The goal of the project was to reveal
the potential that sustainable living has
to become standard practice.
Overall, this was a very smooth
transition, as early on it was decided
that individuals would keep working
with the sustainable elements they had
previously researched and would also
take
responsibility
for
those
corresponding
sections
of
the
modelling tool.
This personal maintenance of the basic
knowledge of the systems being
analyzed helped to save time and avoid
confusion, as team members did not
have to conduct a total handoff of
information to someone unfamiliar
with the characteristics of that
sustainable element.
The downside of this approach is that it
kept information fragmented amongst
group members.
However, to address this issue and help
maintain a cohesive analysis and
report, team members adhered to a
consistent schedule of weekly group
meetings and maintained open lines of
communication between meetings
through the use of email and electronic
databases such as Drop Box and
Google Docs.
References
1. Shiv Lal, S.C. Kaushik, P.K. Bhargav,
(2013), “Solar chimney: A sustainable
approach for ventilation and building
space conditioning”, International Journal
of Development and Sustainability, ISSN:
2168-8662, Volume 2 Number 1, Pages
277-297,
ISDS
Article
ID:
IJDS12110901.
2. Peter O. Akadiri, Ezekiel A. Chinyio, Paul
O. Olomolaiye (2012), “Design of A
Sustainable Building: A Conceptual
Framework
for
Implementing
Sustainability in the Building Sector”,
Journal of Buildings, 2, 126-152, ISSN
2075-5309,
doi:
10.3390/buildings2020126.
3. David Grierson, Carolyn Moultrie (2011),
“Architectural Design Principles and
Processes for Sustainability: Towards a
Typology of Sustainable Building
Design”, Design Principles and Practices:
An International Journal Volume - 5,
Number – 4, ISSN1833-1874.
4. Gan, G. (2011), “General expressions for
the calculation of air flow and heat
ISBN-978-81-932091-2-7
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International Conference & Expo on “Advances in Power Generation from Renewable Energy Sources (APGRES 2017)” December
22-23, 2017 at GEC Banswara, www.apgres.in
transfer rates in tall ventilation cavities”,
Building and Environment, Vol. 46 No.
10, pp. 2069-2080.
5. Macias, M., Gaona, J.A., Luxan, J.M. and
Gomez, G. (2009), “Low cost passive
cooling system for social housing in dry
hot climate”, Energy and Buildings, Vol.
41 No. 9, pp. 915-921.
6. GRIERSON,D.2009,
Towards
Sustainable Building Design, Design
Principles and Practices: An International
Journal, Volume3, Number3, 2009,
ISSN1833-1874.
7. LEED New Construction v,2,2 Reference
Guide, Third Edition, US Green Building
Council, Washington, DC 4.
8. LEED Home Reference Guide, US Green
Building Council, Washington, DC 5.
9. LEED New Construction & Major
Renovation Reference Guide, Version 2.2,
Second edition September 2006, US
Green Building Council, Washington,
DC.
10. Renewable Energy: Wikipedia.com
ISBN-978-81-932091-2-7
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APGRES-2017 Working Committee
Mr. Ankur Kulshreshtha
Mr. Sohan Lal Swami
Mr. Rajendra Prajapati
Mr. Surya P. Meena
Mr. Daljeet Singh
Mr. Shailendra Goswami
Mr. Himanshu Swarnkar
Mr. Praful Patidar
Mr. Prateek Dixit
Mr. Rahul Gangwani
Mr. Aditya P. Dixit
Mr. Aditya Prakash Dixit
Mr. Akhil Nema
Mr. Ravi Prakash Maheshvari
Ms. Sulbha Kothari
Ms. Viveka Soni
Mr. Pradeep K. Tank
Mr. Praveen Rathore
Mr. Kishan Singh Solanki
International Conference & Expo on
Advances in Power
Generation from
Renewable Energy
Sources
(APGRES-2017)
December 22-23, 2017