A new protection scheme for feeders of microgrids with inverter-based resources

Due to the unavailability of a suitable relay for microgrid protection, various utilities are fitting available IEDs for the protection of microgrids. At present, microgrid protection is achieved using a combination of conventional numerical relays. These numerical relays are not suitable for all kinds of microgrid architectures and do not provide complete protection with inverter-based generators. Since these relays were designed considering the fault characteristics of synchronous generators, they fail to respond to the fault characterized by inverter-based generators. This paper proposes a new protection technique that is independent of the type of generating sources, control philosophy of inverters as well as microgrid architecture. Simulations are performed using PSCAD/EMTDC and performance of the protection scheme is also evaluated in real-time using RTDS. Pertinent results are presented which demonstrate the effectiveness of the proposed scheme.