ADAPTIVE COORDINATION OF OVERCURRENT RELAYS IN MICROGRIDS

Abstract

This thesis proposes an adaptive schema to the coordination of inverse-time over current relays that achieve possible optimization for changes in power system as network-topology, load or generation-level to ensure appropriate protective coordination and operating time.The optimal settings for the relays are determined by using Modified Differential Evolution (MDE) algorithm and Firefly algorithm (FA) compared with Genetic algorithm (GA). The aim in selecting the settings of the relays is to achieve the possible minimum operating times while preserving coordination among all relays. The thesis shows that the results using the MDE algorithm and FA algorithm are close to the optimal solutions, and hence demonstrates and proves the validity of the two methods.