This paper presents a methodology to perform closed-loop Traveling Wave Relay Testing (TWRT) for AC power systems on RTDS real-time simulator. The Traveling-Wave Relays (TWRs) have a high sampling rate, e.g., around 1MHz, therefore, it is required that the simulator operates at a small time-step. The TWRs operate based on TW variables that are extracted from the High-Frequency (HF) response of the system. This paper investigates how line models employed in a simulator could affect these variables and illustrates that inaccurate line models could result in spurious TW variables. Therefore, another requirement is to use accurate line models for TWRT. These requirements introduce challenges to real-time simulators for the TWRT application. This paper presents two approaches of RTDS simulator for TWRT: (i) an FPGA-based and (ii) a multi-core CPU-based approach. The proposed methods have been used to test commercially available TWRs and the results are reported.

Hardware-In-the-Loop, Real-time, Traveling-wave, Relay testing.