Protective relay testing and characteristic analysis for high impedance faults in transmission lines

This paper describes the relay testing method and the results for detecting availability of protective relays under high impedance faults (HIFs) in tr ansmission fines. Mho type distance relays, quadrilateral type distance rel ays and PCM type current differential relays are selected for relay testing . Four kinds of model power systems including actual power systems to be us ed for relay testing are established in PSCAD/EMTDC. Each protective relay is tested using RTDS and RTPS. The boundaries of each operating zone are su rveyed by testing. Availability of HIFs detection on each relay are compare d to each other. Impedance variation characteristics at the relay point are investigated using EMTDC in the case that source zero sequence impedance a nd load impedance are varied, The results shown in this paper can be used a s an effective reference to install protective relays in real power systems . (C) 2000 Elsevier Science S.A. All rights reserved.