Graph Theory and Optimization Algorithms Aided Adaptive Protection in Reconfigurable Microgrid

Microgrids interfaced with distributed generators facilitate decentralization of electric power. Bi-directional power flow due to multiple sources and dynamic behaviour of microgrids possess challenges to protection engineers. In this paper, an adaptive protection scheme for a central protection centre (CPC) in a microgrid is proposed. The key functions of the CPC are monitoring the microgrid, identification of fault if any, shortest path identification from a fault to the nearest operating source using Boruvka–Dijkstra graph theory algorithm. It also assigns adaptively the optimized values of time multiplier setting of relays in that path using genetic algorithm, which in turn aids in quick fault clearance. A hardware prototype is developed, tested and validated for a 7-bus microgrid network using Arduino ATmega 1280 for shortest path identification and optimized TMS value assignment for relays in that path using Raspberry Pi Model B+.