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Optimum Time Coordination of Overcurrent Relays using Two Phase Simplex Method

Authors: Prashant P. Bedekar, Sudhir R. Bhide, Vijay S. Kale


Overcurrent (OC) relays are the major protection devices in a distribution system. The operating time of the OC relays are to be coordinated properly to avoid the mal-operation of the backup relays. The OC relay time coordination in ring fed distribution networks is a highly constrained optimization problem which can be stated as a linear programming problem (LPP). The purpose is to find an optimum relay setting to minimize the time of operation of relays and at the same time, to keep the relays properly coordinated to avoid the mal-operation of relays. This paper presents two phase simplex method for optimum time coordination of OC relays. The method is based on the simplex algorithm which is used to find optimum solution of LPP. The method introduces artificial variables to get an initial basic feasible solution (IBFS). Artificial variables are removed using iterative process of first phase which minimizes the auxiliary objective function. The second phase minimizes the original objective function and gives the optimum time coordination of OC relays.

Keywords: Constrained optimization, LPP, Overcurrent relaycoordination, Two-phase simplex method.

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[1] Y.G.Paithankar, and S.R. Bhide, "Fundamentals of Power System Protection", Prentice Hall of India Private Limited, New Delhi, 2007.
[2] B.Ravindranath, and M. Chander, "Power SystemProtection and Switchgear", New Age International (P) Limited Publishers, New Delhi, 2006.
[3] C.R.Mason, "The Art and Science of Protective Relaying", John Wiley and Sons, New York, 1956.
[4] A.R.C.Van Warrington, Protective Relays, Their Theory and Practice", John Wiley and Sons, New York, 1969.
[5] A.J. Urdaneta, Nadira Ramon, and Luis G.P. Jimenez, "Optimal Coordination of Directional Relays in Interconnected Power System", IEEE Trans. on Power Delivery, Vol 3, No. 3, July 1988, pp. 903-911.
[6] P.P. Bedekar, S.R. Bhide, and V.S. Kale, "Coordination of Overcurrent Relays in Distribution System using Linear Programming Technique", Proceedings of the International Conference on Control Automation Communication and Energy Conservation (INCACEC-2009), Kongu Engineering College, Erode (India), June 2009, pp. 905-908.
[7] H. Zeienldin, El-Saadany and M.A. Salama, "A Novel Problem Formulation for Directional Overcurrent Relay Coordination," Large Engineering Systems Conference on Power Engineering 2004 (LESCOPE-04), 2004, pp. 48-52.
[8] A.J. Urdaneta, H. Restrepo, S. Marquez, and J. Sanchez, "Coordination of Directional Relay Timing using Linear Programming", IEEE Trans. on Power Delivery, Vol 11, Jan 1996, pp. 122-129.
[9] B. Chattopadhyay, M.S. Sachdev, and T.S. Sidhu, "An Online Relay Coordination algorithm for Adaptive Protection using Linear Programming Technique", IEEE Trans. on Power Delivery, Vol 11, Jan 1996, pp. 165-173.
[10] H.A. Abhyaneh, M. Al-Dabbagh, H.K. Karegar, S.H.H. Sadeghi, and R.A.J. Khan, "A New Optimal Approach for Coordination of Directional Overcurrent Relays in Interconnected Power System", IEEE Trans. on Power Delivery, Vol 18, April 2003, pp. 430-435.
[11] S.A. Soman, Lectures on Power System Protection (Availablewww. online), module 5, lecture 19. Last accessed on Dec 25, 2009.
[12] C.W. So, and K.K.Li, "Overcurrent Relay Coordination by Evolutionary Programming", Electric Power System Research, Vol 53, 2000, pp. 83-90.
[13] S.S. Rao, Engineering Optimization - Theory and Practice, 3rd edition, New Age International Pvt. Ltd., New Delhi, p. 152-164, (1998).
[14] Taha H., Operations Research - An Introduction, eighth edition, Dorling Kindersley (India) Pvt.Ltd., New Delhi, p. 85-95, (2009).
[15] Winston W.L., Operations Research - Applications and Algorithms, fourth edition, Thomson Learning Inc., p. 140-151, (2007).
[16] Sharma J.K., Operations Research - Theory and Applications, Third edition, Macmillan India Limited, New Delhi, p. 131-160, (2009).
[17] P. Sankara Iyer, "Operations Research", Tata McGraw Hill Publishing Company Limited, New Delhi, 2009.