Optimum Overcurrent Relay’s Coordination Using Multiple Standard Relays Characteristics

Relay Coordination is very crucial task as it required coordination of primary and backup relays. in past various authors have proposed modification in standard overcurrent relays characteristic, modification in objective function to achieve optimum results of operating time of primary as well as backup relays. In this paper, considering normal inverse, very inverse and extremely inverse standard relays characteristic, optimized results are obtained using PSO, GA, HAS. Further these results have been validated on radial distribution system.