Linear programming technique based optimal relay coordination in a radial distribution system
Keywords:Inverse Relay, Linear Programming Problem, Optimal Relay Co-Ordination, Time Dial Setting.
Now-a-days to ensure power continuity and systemâ€™s reliability the protection system is to be designed properly for distribution systems to handle the faults to avoiding the damage to the equipments and to the service engineers. Different types of relays with different working principles are used to detect different types of faults in the system. In order to avoid mal operation of relays, proper coordination is to be carried out. The objective of this paper is to maintain the relay coordination as well as to decrease the working time of relays by optimizing the values of time dial setting (TDS) using linear programming problem technique (LPP). The inequality constraints guarantee the coordination margin for each primary or backup relay pairs having a fault very close to the primary relay. Simulation is carried out on a IEEE 15 bus balanced radial distribution system with 3 different types of relays namely standard inverse, extremely inverse and very inverse relay and the results are presented and analyzed.
 Badri Ram, D. N. Vishwakarma,â€ Power System Protection and Switchgearâ€, Tata McGraw-hill, Page no.68-71.
 R. E. Albrecht et al. â€˜Digital Computer Protective Device Coordination program â€“I general Program Descriptionâ€™, IEEE Trans on PAS, Vol. 83, No 4, April 1964, pp. 402-410. https://doi.org/10.1109/TPAS.1964.4766018.
 M. J. Damborg, et al. â€˜Computer Aided Transmission Protection System Design, Part I: Algorithmsâ€™, IEEE Trans on PAS, Vol. 103, No 4, 1984.
 L. Jenkines, H. Khincha, S. Shivakumar and P. Dash. â€œAn Application of Functional Dependencies to the Topological Analysis of Protection Schemesâ€, IEEE Transaction on Power Delivery, Vol. 7, No. 1, January 1992, pp. 77-83. https://doi.org/10.1109/61.108892.
 A. J. Urdenta, et al. â€œOptimal Coordination of Directional Over current Relays in Interconnected Power Systemsâ€, IEEE Trans. on Power Delivery, Vol. 3, July 1988, pp.903-911. https://doi.org/10.1109/61.193867.
 JavadSadeh ,â€ optimal coordination of over current relays in an interconnected power systemâ€, 15th PSCC, Liege, 22-26 August 2005, Session 19, Page 1
 A. S. Braga and J. Tome Saraiva, "Coordination of overcurrent directional relays in meshed networks using the Simplex method," Proceedings of 8th Mediterranean Electrotechnical Conference on Industrial Applications in Power Systems, Computer Science and Telecommunications (MELECON 96), Bari, 1996, pp. 1535-1538 vol.3. https://doi.org/10.1109/MELCON.1996.551243.
 B. Chattopadhyay, M. S. Sachdev and T. S. Sidhu, â€œAn On- Line Relay Coordination Algorithm For Adaptive Protection Using Linear Programming Techniqueâ€, IEEE Transactions on Power Delivery, Vol. 11, No. 1, January 1996, pp.165-173. https://doi.org/10.1109/61.484013.
 A. J. Urdenta, L. G. Perez, and H. Resterbo, â€œOptimal Coordination of Directional Overcurrent Relays Coordinating Dynamic Changes in the Network Topologyâ€, IEEE Transaction on Power Delivery, Vol. 12, No. 4, October 1997, pp.1458-1464. https://doi.org/10.1109/61.634161.
 Abdelaziz AY, Talaat HEA, Nosseir AI, Hajjar AA. An adaptive protection scheme for optimal coordination of over current relays. Elect. Power Syst. Res. 2002; 61(1):1-9. https://doi.org/10.1016/S0378-7796(01)00176-6.
 A. H. Knable, Electrical Power System Engineering Problems and Solutions, McGraw Hill, New York, Uma U.Uma, I.K.Onwuka, â€œOver current Relay Setting Model for effective Substation Relay Coordinationâ€, Iosr Journal Of Engineering (Iosrjen), Vol. 04, Issue 05 (May. 2014), PP 26-31, 1967
 S. S. Gokhale and V. S. Kale, "Application of the Firefly algorithm to optimal over-current relay coordination," 2014 International Conference on Optimization of Electrical and Electronic Equipment (OPTIM), Bran, 2014, pp. 150-154. https://doi.org/10.1109/OPTIM.2014.6850887.
 C. W. So, K. K. Li, K. T. Lai, and K. Y. Fung, â€œApplication of genetic algorithm for over current relay coordination,â€ in Proc. IEE Developments in Power System Protection Conf., 1997, pp. 66â€“69.
 C. W. So and K. K. Li, â€œTime coordination method for power system protection by evolutionary algorithm,â€ IEEE Trans. Ind. Appl., vol. 36, no. 5, pp. 1235â€“1240, Sep./Oct. 2000. https://doi.org/10.1109/28.871269.