Enhanced protection for inverter dominated microgrid using transient fault information

Protection of an inverter dominated microgrid is always a great challenge, as inverters are well known for their insufficient contribution to the fault current, undermining the accuracy and viability of traditional overcurrent protection schemes. Based on the wide review of solutions developed in the past, this paper proposes a novel protection strategy, with the main protection method based on the time and polarity features of initial current travelling waves using mathematical morphology (MM) technology and backup protection strategy based on the rate of change of current. Simulation tests in PSCAD/EMTDC considering different fault resistances, fault positions and fault inception angles prove this protection approach to be sensitive and reliable.