Testing Methodology for Performance Evaluation of Distance Protection Relays for Transmission Systems

This paper proposes a dynamic testing methodology for the evaluation of the performance of the distance protection function and ancillary functions of distance relays by taking into account specific utility's requirements. To this aim, an RTDS (R)-based hardware-in-the-loop testing platform is developed and a comprehensive set of test cases is proposed, which are specifically elaborated to cover a broader spectrum of critical scenarios as compared to state-of-the-art distance protection testing approaches. The proposed testing methodology is employed in an ad-hoc developed use case to evaluate the performance of two commercial relays according to regulatory limits specific to the Provincial Electricity Authority, a system operator of Thailand. The results show that the relays under test may lead to unexpected operations of the distance protection function (e.g., lockout state at the boundary of zone 1) and ancillary functions (e.g., tele-protection scheme). Hence, the proposed test cases allow to successfully pinpoint potential integration issues before the device implementation into the field.