Modified Grey Wolf Optimization Algorithm for Directional Overcurrent Relays Coordination in Distribution Network With Distributed Generations

Directional overcurrent relays (DOCRs) must be as optimal coordination as feasible for electrical system networks to offer reliable and effective protection. This challenge has become more complex recently due to the growing utilization of distributed generation (DG). In this study, a modified variant of grey wolf optimization (MGWO) is proposed as an approach to the DOCRs coordination problem in the existence of DG. Reducing the operating time of all primary relays is considered, where the operating time depends on the time dial and pickup current setting. The MGWO resolved the issue of sluggish convergence and the potential risk of getting stuck in locally optimal solutions. The effectiveness of the proposed MGWO is evaluated using a 7-bus radial distribution network system in two case studies and validated using ETAP software. The results confirmed that the proposed MGWO improved the objective function of the DOCRs coordination problem in all cases and showed that the total operating time of the primary relays was reduced from 1.07% up to 10.18% compared to the original GWO.