Study on Adaptation of Traveling Waves Based on Wavelet Transform for Fault Location in Automatic Blocking and Continuous Power Transmission Lines

The theory of traveling waves and its wavelet representation were presented. The characteristics and fault location research actuality in railway automatic blocking and continuous power transmission line were introduced. Considering the influence of the bus bar, conductor’s architecture and the load along the line, the adaptation of traveling waves was analyzed. A method to locate fault by combining zero modal and aerial modal was brought forth, i. e., to distinguish the reflected wave of the faulty point from that of the bus at the opposite terminal by zero mode components and to locate the faulty position by aerial mode component. As for the mixed line, some characteristics can be obtained from the combination of aerial modal and zero modal of fault current, therefore the fault section can be determined. The modeling and simulation of the proposed method are conducted by software PSCAD/EMTDC. The simulation results show that the proposed method is feasible.

I. Introduction

Railway automatic blocking and continuous transmission line(RABCTL) is a non-directed to ground system, but it is different from the power system distribution network, there are just two feeders, the feeders are long, the conductors is the mixed of overhead lines and cables, and the tapped loads distributed all along the transmission lines^[1]. All of these characteristics determine that its fault location is hard to detect and up to now all products have bad precision. Now only conventional protect equipment are installed in RABCTL, when some faults happen, especially single phase to ground fault, it is hard to find its location, left the system inoperative. In ref. 2, a RABCTL comprehensive fault detection system realizes the detection of the fault section and removes it automatically. This system can minimize the fault rang and lessen the time for fault detecting, but it can not locate the fault precisely. Therefore, to study and apply correct fault location methods to fault location in RABCTL, and improve the reliability of RABCTL have important realistic meaning.