Presented by: Roopa Ramachandran and Bhargav Sai Badur, Southern Company
The study discusses the development and use of an RTDS platform to evaluate protection system performance in inverter-based resource (IBR) dominated transmission grids. As synchronous generation is increasingly replaced by inverter-based resources, grid response during disturbances can change significantly, producing atypical, rapidly varying, or distorted voltage and current signatures that challenge traditional protection assumptions and increase the risk of mis-operation or failure to operate. To analyze these impacts, a protection oriented real-time EMT model was developed in RTDS with detailed substation network representation, source and IBR modeling, measurement points, relay and breaker operations, and fault simulation capability.
This work introduces IBR integration in stages and examines how increasing IBR penetration influences legacy protection and system behavior. Practical modeling considerations are discussed, including the need to balance detailed IBR representation with real-time simulation scalability and systematic evaluation of transmission line protection performance under reduced fault current. The RTDS platform provides a controlled environment to compare disturbance response, observe fault current characteristics, and assess implications for protection performance.
The study highlights key IBR modeling decisions, and distance protection focused observations from RTDS simulations. The results demonstrate that static legacy protection settings are insufficient for high CIR penetration scenarios.