Improved group search optimization algorithm for coordination of directional overcurrent relays

In this study, coordination of directional overcurrent relays in power systems is formulated as an optimization problem. The objective is to find out an optimum setting of relays in order to minimize the operating time of relays for faults at their primary protection zone, while coordinating the relays properly. The coordination is performed using Improved Group Search Optimization algorithm. This paper introduces IGSO by applying some modifications to the original GSO in order to improve its searching ability. In order to validate the efficiency of the proposed IGSO, comprehensive simulation studies are carried out. The simulation studies include some benchmark test functions and test power systems. The results are compared with some existing analytic and evolutionary methods. Numerical results confirm efficiency of the proposed method in comparison with some recently published papers. (C) 2015 Published by Elsevier B.V.