Inverter Fault Current Multiplier for Grid-Interactive Converters

The increasing penetration of inverter-based resources (IBRs) in power systems is radically challenging existing overcurrent protection practices. Traditional overcurrent protection devices may not be equipped to provide sensitive and selective fault tripping capabilities due to the significantly limited and variable fault current contributions of IBRs. This paper presents an Inverter Fault Current Multiplier (IFCM) architecture for grid-interactive power converters. The IFCM is a novel power electronics platform integrated with semiconductor switches and a transformer that amplifies the fault current contribution from IBRs to trip conventional protection devices. Furthermore, integrated sensors and controllers in the IFCM packaging facilitate a decentralized operating mechanism that allows it to be integrated with a power system's existing overcurrent protection infrastructure, eliminating the need for resource-intensive system upgrade efforts. This paper illustrates the operating mechanism of the IFCM and its impact on meeting the overcurrent protection needs of an IBR-rich grid. Hardware results from a lab-scale prototype and finite-element simulation validation of the concept are also provided at residential voltage levels, demonstrating the feasibility of the IFCM.