Study On Technology Of Fault Location Based On Travelling Waves In Direct Feeding Traction Lines

The railway power supply system is an independent and particular branch of the power system; electric locomotive gets current through sliding between the pantograph and the catenaries of power supply system. The traction condition is poor and the traction loads are special, thus the impedance method used in fault location techniques is difficult to overcome the impact of transition resistance, so that once there is a fault in traction lines, it is hard to find out the fault location effectively and timely. The field needs effective and practical fault location or distance measurement technology urgently.In the light of the fault location adopting the method of traveling wave applied successfully in the transmission lines, the paper applies the traveling wave location principle into the fault location of the common use direct feeding traction power supply system and resolve the critical technology in application, so that to meet the practical requirements.The article analyzes structure of the traction line firstly from the view of traveling wave based fault location, including anchor section, branch line and the way station cut-off lines. On base of those, a classic traction line model suitable to the traveling wave fault location is established. The paper analyses the characteristics of the transient voltage and current traveling waves generated form the catenaries earth-fault, the faults between the catenaries and the return line and the break line fault in the direct feed with return lines. In view of the different structure (Terminal in parallel and in open-circuit) in the double traction line, the paper describes propagation characteristic of the voltage and current traveling waves in the bus and terminal ends. The propagation characteristics of the traveling waves in the special structure and the effects to the traveling wave fault location are analyzed; combining with the utilization ways of traveling waves, the construction and service mode of fault location setting based on traveling waves in traction lines is introduced; the acquirement of travelling wave signals is discussed; the effect of electric locomotive, the initial phase angle of fault, transition resistance, fault position on the location reliability of traveling waves is analyzed; the generation and propagation characteristics of fault traveling waves is simulated with ATP, and this technique has passed the examination of manual test and running-in test.From the theory analysis, the following can be gotten: with the transient traveling waves generated by the fault, the fault distance can be measured effectively and accurately, two terminals theory of fault location should be used in traction lines; the required signal must be voltage traveling waves at the Single outlet bus or terminal in open-circuit, and the voltage traveling waves or current traveling waves can both be selected at the Two outlet bus or terminal in parallel. the acquirement of signal with the existing TV and TA is discussed; for lines without TV, the traveling waves acquirement can be achieved by the using self-consumption transformer in substation.The result of simulation and operation has proved its feasibility and practicability.The fault location methods of traveling waves which used in direct feeding traction lines and proposed in this article make the most of existing measuring transformer and need no additional primary settings. The method has the advantage of high precision, simple theory, easy realization and wide application, which has a bright foreground.