Fault Location On Railway Power Lines Using Travelling Wave Transients

The automatic blocking and continuous railway power lines (ABCRPLs) provide power for the signaling systems used in train traffic control. Fast fault location is critical to ensure power supply reliability and the safe running of trains. At present, fault location methods for ABCRPL are based on impedance measurements whose accuracies are satisfactory as the results of influences of fault resistance, distributed capacitance, faulty transient component, transformer errors, etc. In the absence of a more reliable fault location method (especially for single phase to ground faults) many railway authorities are obliged to use visual inspection patrols to locate faults on their power lines.The adaptation of D-type fault location principle to railway power lines is presented in this paper. The works done are as follows: (1) Analysis of characteristics of traveling waves generated by interphase short-circuit and single phase to ground (earth) faults on ABCRPLs. (2) The responses of existing transformers on ABCRPLs to fault generated traveling wave are analyzed. A D-type double-ends fault location method using traveling w aves is proposed, which makes use of transient phase tophase voltage outputs {uAB or uCB ) of voltage transformers at both ends of the line.(3) The proposed fault location method is verified by digital simulation using ATP-Matlab software.(4) A prototype traveling wave fault location system was designed based on the proposed method. The field trial results proved that the proposed technique is feasible and that it provides fault location accuracy better than ±1km.Fault location technique using traveling waves has better accuracy as the seeped of traveling wave is close to the velocity of light and is free of influences of fault resistance, circuit structure and transformer errors. The method presented in the paper make use of outputs of existing voltage transformers and does not requireadditional transducers. The technique offers many advantages such as simplicity, cost effective and adaptivity. Its application in railway network will certainly help to increase supply reliability and reduce operation cost.