Optimal Coordination of Directional Overcurrent Relays Considering a Modified Objective Function Using Genetic Algorithm

Abstract

Directional Overcurrent Relays (DOCR) are widely used in meshed distribution and sub-transmission networks to provide inexpensive primary protection and in transmission systems as the second line of protection to distance and/or differential protection relays that serve as the primary protection system. DOCR operation settings (current Pick-up $I_{pickup}$ and Time Multiplier Setting TMS) must ensure that the protection system maintains selectivity during fault isolation at all times. For optimal setting and coordinated operation of DOCR relays, this paper proposes a modified objective function and is tested using a genetic algorithm to obtain the optimal settings for the IEEE 8-bus test grid.