Abstract:Aiming at the problem that the traditional constant current relay protection can not respond to the topology changes of microgrid in time, a decentralized adaptive overcurrent protection scheme is proposed. According to the fault characteristics of microgrid, the feeders in microgrid are divided into upstream area and downstream area with the distributed generator (DG) as the center.And distributed protection laws based on instantaneous relays are configured for different regions. Finally, the microgrid model is built on PSCAD/EMTDC platform to test different types of faults. The results show that the proposed method can correctly cut off faults in different operation modes, topology and DG operation states of microgrid, and can improve the reliability of protection.