Impact of Inverter-Based Resources on Different Implementations of Distance Relays—Part II: Reactance Method

Part I of this paper investigated the performance of distance relays that use phase comparators in systems with inverter-based resources (IBRs). Part II investigates distance relays implemented using the reactance method, as one of the most common methods used by commercial relays. This paper reveals that IBRs adversely impact the performance of distance relays that use this method. The ground and phase elements of the reactance method are prone to under-/over-reach in systems with IBRs. Through a detailed analysis, the root causes of the failures along with the possible measures to alleviate them are discussed. Moreover, it is unveiled that the misoperation of the reactance method is not limited to only the relay that protects the IBR tie-line and can happen for the relays across the system. The paper also demonstrates that the IBR's compliance with the low-voltage ride-through requirements of recent grid codes, including generation of negative-sequence reactive current, directly impacts reliable operation of distance relays in proximity of these sources. Findings of the paper are corroborated using PSCAD/EMTDC simulations.