HIGHLY SENSITIVE MICROGRID PROTECTION USINGOVERCURRENT RELAYS WITH A NOVEL RELAYCHARACTERISTIC

Abstract

Following the high penetration of synchronous generators (SGs) in the power network, optimal overcurrentcoordination improvement under faulty conditions has become a crucial problem. To reduce the overcurrent relay operatingtime, a new overcurrent relay curve is proposed in this study. Then, the overcurrent coordination problem is overcome by usinga robust combinatorial optimisation method. Additionally, SG sizing and location is performed to verify the merits of both theproposed relay curve and the applied optimisation algorithm. The proposed relay curve performance is compared with othernon-standard relays characteristic available in the literature for a standard microgrid. Then, the proposed relay curve is appliedto both the 8-bus transmission and the 33 kV distribution portion of the 30-bus IEEE standard power test systems. Then, the SGtransient stability for different fault locations is analysed. Finally, an accurate comparison between the proposed relay curve andstandard/non-standard curves available in the literature is provided by applying the same optimisation method and networktopology. The simulation results confirm the superiority of the proposed relay curve