Mobile QR Code QR CODE : The Transactions of the Korean Institute of Electrical Engineers
Title The Advanced Protection Coordination Scheme using Phase Angle of Zero-Sequence Current in Ungrounded System
Authors 최영준(Choi, Young-Jun) ; 임희택(Lim, Hee-Taek) ; 최면송(Choi, Myeon-Song) ; 이승재(Lee, Seung-Jae)
Page pp.19-25
ISSN 1975-8359
Keywords Distribution System ; Distribution Automation ; Ungrounded System ; Protection Coordination ; Zero-Sequence Current
Abstract Most faults are single-phase-to-ground fault in ungrounded system. The fault currents of single-phase-to-ground are much smaller than detection thresholds of measurement devices, so detecting single-phase-to-ground faults is difficult and important in ungrounded system. The protection coordination method using SGR(Selective Ground Relay) and OVGR(Overvoltage Ground Relay) is generally used in ungrounded system. But this method only detects fault line and it has the possibility of malfunction. This paper proposed to advanced protection coordination method in ungrounded system. The method just using zero-sequence current can detect fault line, fault phase, fault section at terminal device. The general protection method is used to back up protection. In the case study, the proposed method has been testified in demo system by Matlab/Simulink simulations.