This document summarizes a thesis on optimally placing and sizing capacitor banks in a radial distribution system to improve voltage profile and reduce losses, and the effects of adding distributed generation. The study formulates an objective function to minimize losses and maximize voltages. Optimal capacitor placement is performed using genetic algorithms in ETAP software. Manual placement of capacitor banks is also evaluated. Adding distributed generation along with capacitors is found to further improve voltages and reduce losses compared to capacitors alone. The conclusion discusses benefits of compensation and future work on switching technologies and soft computing techniques for optimization.

1. Optimal Placement and Sizing of Capacitor Banks
Based on Voltage Profile and Losses in Radial
Distribution System and Effects of DG Addition
By
Prashanta Sarkar (11PEE010)
M.Tech,Power System
Supervisors
Saheli Ray & Dr. Subhadeep Bhattacharjee
DEPARTMENT OF ELECTRICAL ENGINEERING
NATIONAL INSTITUTE OF TECHNOLOGY AGARTALA
MAY- 2013
1

2. Outline of Presentation
Introduction.
Test System.
Problem formulation.
Result and discussion.
Conclusion.
Future Scope.
Publication
References.
2

3. Introduction
Reactive power compensation.
Optimal capacitor placement(OCP) using GA
Compensation using capacitor banks &
….Distributed Generation(DG)
3

4. Test System
Load Loss
Load-MW 12.817 Loss-KW 393
Load-MVAR 6.6 Loss-KVAR 806.
4

5. PROBLEM FORMULATION
Two goals for determining the formula that are used in point of start
1. Loss Reductions.
2. Voltage profile Improvement.
The main constraints in the optimization process in the proposed
methodology are:
1. Loss with OCP ≤ Loss without OCP
2. V bus min ≤ V bus ≤ V bus max
5

6. The objective function, with composing constraints and goals, is determined as
following:
k1, k2 , k3 : Emphasis or penalty factors
n : Number of Buses
m : Number of Branches.
( )1
1
2
1
3
1
1
0, % %
0,
,
n
iwithOCP iwithoutOCP
i
m
jwithoutOCP jwithOCP
j
m
jwithoutOCP jwithOCP
j
MaxF K Max Voltage Voltage
n
K Max P P
K Max o Q Q
=
=
=
  
= − +  
  
    
− +   ÷
     
    
−   ÷
     
∑
∑
∑
6

7. Optimal capacitor placement using GA in ETAP
 Simulating the system in ETAP 38 no. of capacitor can be placed for OCP
Min voltage (%)
Min voltage(%) before OCP Min voltage(%) after OCP
93.01 96.41
Max voltage (%)
Max voltage(%) before OCP Max voltage(%) after OCP
98.45 100.06
Power losses in
…….. KW
Power losses in KW before
OCP
Power losses in KW after
OCP
393 325
Capacitor cost($)
----------------- 1260000.00
Cost of real power loss
($)
Cost of real power loss before
OCP
Cost of real power loss after
OCP
1205 1009
Benefit($/year)
Benefit($/year) after OCP Benefit($/year) after OCP
----------------------- 118981.00
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8. Accumulative profit of the total planning period gives a profit of 1105820.00 $.
Voltage profile between optimal capacitor placements and uncompensated system
8

9. MANUAL PLACEMENT OF CAPACITOR
Urge for manual capacitor placement
Placing of 2 capacitor banks at bus no 10, 58 of 700,1400 KVAR rating
9

10. Placing of 3 capacitor banks at bus no 16, 52 & 58 of 650,800 & 600 KVAR
Placing of 4 capacitor banks at bus no 10,16, 52 & 58 of 500,200,700 & 600
KVAR
10

11. Placing of 5 capacitor banks at bus no 10,16, 47 ,52 & 58 of 550,100,550,450 & 300
KVAR
Voltage profile between all the cases of capacitor banks placements and uncompensated
system
11

12. Comparison between multiple capacitor bank placements
12
Element
2 capacitor
bank
3 capacitor bank 4 capacitor bank 5 capacitor bank Un
Compensated
system
Min
voltage (%)
95.01 95.00 95.00 95.00 93.01
Max
voltage (%)
98.87 98.85 98.85 98.84 98.45
Active Power
losses (KW)
366 KW 367 KW 364 KW 364 KW 393 KW
Reactive Power
losses (KVAR)
754 KVAR 747 KVAR 743 KVAR 741 KVAR 806 KVAR

13. COMPENSATION USING CAPACITOR BANKS & DG
Placing of 5 capacitor banks at bus no 10,16, 47 ,52 & 58 of 550,100,550,450 &
300 KVAR & 3 DG at bus no. 21,42 & 56 of 0.5 MW Rating
13

14. Placing of 5 capacitor banks at bus no 10,16, 47 ,52 & 58 of
550,100,550,450 & 300 KVAR & 3 DG at bus no. 21,42 & 56 of 1 MW
14

15. Voltage (%) profile improvement curve with DG rating 0.5 MW & 1 MW
15

16. Voltage & Power Loss comparisons with Capacitor
Banks
& DG
16
Element
5 capacitor bank & 3
DG of 0.5 MW rating
5 capacitor bank & 3 DG of 1
MW rating
Min voltage(%) 96.09 97.04
Max voltage(%) 99.10 99.34
Active Power losses (KW) 261 KW 197 KW
Reactive Power losses (KVAR) 570 KVAR 465 KVAR

17. Conclusion
The study of OCP in 60 bus radial distribution system is helpful
in long term investment.
Manual placement of capacitor may result lower investment .
The compensation of reactive power is limited to some
extent, but for good solution of optimization both active and
reactive power compensation is essential.
DG in the system may resolve many other issues (power
islanding, stability).
17

18. Future scope
Implementing a switching technology for exact
combination of DG and capacitor bank.
Soft computing technique to determine DG & capacitor …
ratings.
Selection of DG technology.
18

19. Publication
Prashanta Sarkar, Soumesh Chatterjee, Saheli Ray, Optimal Placement
of Capacitor for Voltage Support and Minimizing Overall Cost in
Radial Distribution System, International Journal of Computer Applications
(0975 – 8887) Volume 65– No.2, March 2013
19

20. Reference
[1] An Introduction to Reactive Power,The National Grid Company plc, Market
,Development: October 2001,pp.1-3.
[2] Pravin Chopade and Dr. Marwan Bikdash “Minimizing Cost and Power loss by
Optimal Placement of Capacitor using ETAP”,978-1- 4244 - 9593-1, 2011 …
IEEE,pp.24-29.
[3] H. Omidi, B. Mozafari, A. Parastar, M.A. Khaburi, “Voltage Stability Margin
Improvement using Shunt Capacitors and Active and Reactive Power
Management”,978-1-4244-4509-7/09, pp 1 - 5.
[4] Narain G. Hingoranl, Laszlo Gyugyi, Understanding Facts, 0-7803-3455-
8,Chapter 5, pp.135-205.
[5] Aoki k, Ichimori T, Kanezashi M. (1985), “Normal state optimal load allocation in
distribution systems”, IEEE Trans Power Delivery, Volume 3(issue 1), pp. 147-155.
[6] ETAP 7.0.0 Product Overview – Power System Enterprise Solution, Operation
Technology Inc.
20

21. [7] Soumesh Chatterjee, Sharmistha Sharma, “Advantage of DG To Mitigate Voltage
Collapse over Facts Devices”, International Journal of Engineering Research and
Applications; Vol. 2, Issue6, November- December 2012, pp.1253-1257.
[8] H. Lee Willis, “Analytical methods and rules of thumb for modeling DG-
distribution interaction”, 0-7803-6420-1/00,IEEE,pp. 1643-1644.
[9] IEEE Recommended Practices and Requirements for Harmonic Control in
Electrical Power Systems , IEEE Std. 519-1992, 1993.
[10] Y. Alinejad - Beromi, M. Sedighizadeh, M. R. Bayat and M. E. Khodayar,“Using
genetic algoritm for distributed generation allocation to reduce losses and improve
voltage profile”, UPEC 2007 – 954.pp. 1-6.
[11] R. Srinivasa Rao and S. V. L. Narasimham, “Optimal Capacitor Placement in a
Radial Distribution System using Plant Growth Simulation Algorithm”,World
Academy of Science, Engineering and Technology 21 2008.pp 715-722.
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22. [12] Gunnet Kour, Dr. G.S Brar & Dr. Jaswanti , “Optimal placement of static var
compensators in power system”, IJEST, vol. 4 No. 05 May 2012, pp. 2030-2036
[13]Mohammad Hadi Molaei Ardakani, Mohammad Zarei Mahmud Abadi,
Mohammad Hossein Zabihi Mahmud Abadi and Azim khodadadi,“Distributed
Generation and Capacitor Banks Placement in Order to Achieve the Optimal Real
Power losses using GA”, IJCST Vol. 2, Issue 4, Oct . - Dec. 2011,pp. 400-404.
[14] B.F. Wollenberg, “Transmission system reactive power compensation”, IEEE
Power Engineering Society Winter Meeting, 27-31 Jan. 2002, vol.1, pp. 507 – 508.
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23. Thank You
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