The growing proliferation of distributed Inverter-Based Resources (IBR) such as Battery Energy Storage Systems (BESS) and Solar Photovoltaic (PV) systems has created both challenges and opportunities for electric utilities. For instance, advances in control of IBRs have paved paths for deployment of microgrids to increase the reliability and resiliency of the electric power system. However, microgrids pose significant operational challenges to the distribution systems due to various operating modes, fault current characteristics, fast response of nontraditional energy resources, and advanced automation schemes. One of the main microgrid challenges is the design of a reliable protection scheme that operates in both grid-connected and island modes. Designing overcurrent, voltage, and frequency protection schemes for microgrids requires special studies and testing to ensure that the protection system is sufficiently sensitive and selective. This is particularly important due to non-conventional fault behavior of grid-forming inverters as a dominant source of energy in the island mode.
This presentation focuses on protection system testing for utility microgrids embedding grid-forming Inverters before field deployment. The microgrid system is simulated in a Real-Time Digital Simulator (RTDS) and interfaced with several protective relays that are utilized to protect the microgrid. The effectiveness of the proposed protection system is evaluated through comprehensive Controller Hardware-in-the Loop (CHIL) testing, considering the interaction with the microgrid control system during various system operating conditions and faults.
Ahmad Momeni, Quanta Technology