Protection of Inverter-Based Resources Under Open-Circuit Breaker Malfunction

Power system protection ensures the safe and reliable delivery of electric power to customers. The increasing number of inverter-based resources (IBR) creates challenges for conventional power system protection as IBRs respond differently to faults than synchronous generators (SG). This means that protection schemes need to be modified to ensure proper power system protection. Currently, most of the proposed IBR protection schemes focus on short-circuit (SC) faults. However, open-circuit (OC) faults also occur in the power system and cause unbalanced currents, overvoltages, and degraded power quality. This paper proposes an OC fault protection scheme for an IBR connected in a transmission system. The IBR control system is studied first. The response of an IBR to an OC fault is studied next. Finally, a protection logic is proposed to detect and clear OC faults. The performance of the proposed scheme is evaluated under time-domain simulation case studies using PSCAD/EMTDC software package.