Fault location of transmission lines connecting with short branches based on polarity and arrival time of asynchronously recorded traveling waves

Abstract

Due to complex reflection and refraction at line terminals, traditional single-end traveling wave (TW) fault location (FL) cannot be directly applied to transmission lines connecting with short branches. This paper presents an improved single-end TW FL method for this special case. Three TW recorders are required to be mounted at local, middle and remote terminals of the transmission line but accurate synchronous sampling is not required. In the proposed method, combined with the defined polarity coefficients of current TW wave fronts (WFs), the absolute difference of the time differences of arrival (TDOAs) of the modulus TWs at both terminals is firstly utilized to determine whether the fault occurs in the transmission line. If the fault is detected in the transmission line, the fault line section can be then determined by the ratio of the TDOAs of the modulus TWs recorded at both terminals. Finally, the TDOAs of the first two WFs at the three TW recorders are calculated and compared with the theoretical ones to determine the source of the second WF. The corresponding single-end accurate FL formula is selected to pinpoint the fault. A simulation model of a transmission line connecting with short branches is constructed by PSCAD/EMTDC. Various faults are simulated to verify the proposed FL method. The calculation results demonstrate that the method is not affected by FLs, impedances, inception angles, noises and longer lines to a certain extent.