High-speed Railway AT Traction Power Supply System Of Lightning Overvoltage

In recent years, Most of the railways in our country have realized the electrification. At the same time, China’s high-speed railway operating mileage has exceeded 10 thousand km. Along with the popularity of high-speed railway, high-speed railway is changing people’s lives, faster and more comfortable experience make more and more people enjoy the convenience brought by high-speed railway. The normal operation of traction power supply system is the basic condition of high speed rail, to make sure the train more safety, stability and high speed operation. Therefore, the high-speed railway traction power supply system is safe and reliable operation directly related to people’s daily life and the stability of the railway operation.The structure of high speed railway traction power supply system is complex, the lines involved covered most of the land area in our country, with different local climate conditions, especially the lightning weather. In order to running in the normal operation, Traction power supply system of high speed railway has brought great challenges. High amplitude lightning for a short time can result in traction substation tripping even traction network disconnection, making trains lose power and cannot running in normal state, seriously impact the safe operation of high-speed railway. Qualitative understanding the influence caused by lightning overvoltage of traction power supply system, can provide a theoretical basis to the design and engineering, so to reduce the power outage accidents caused by lightning, and ensure the normal operation of high-speed railway. China’s high-speed railway traction power supply system usually use the AT(Auto-Transformer, autotransformer) power supply mode, so as to ensure the safe and reliable operation of high speed railway, research in high-speed railway traction system of lightning over voltage research is of great significance.First of all, this paper introduces the basic principles of AT traction power supply system, using multi conductor transmission line theory to calculate the traction network strands of wire resistance and inductance parameters, and then get the AT power supply line impedance and admittance matrices, and combined the traction network of 14 wire to six coupled line impedance matrix and the capacitance matrix equivalently. By using the line parameter matrix, the simulation model of AT traction power supply network is built on the PSCAD platform. To different lightning simulation analysis of traction network line lightning overvoltage data; then the traction network was erected arrester simulation, analysis of the lightning arrester installed after the over voltage level, and has carried on the analysis to the influence of substation tripping rate. The simulation results show that, before installing the lightning arrester, direct lightning stroke contact line and feeder will cause the traction network voltage level to reach hundreds of kV, and the lightning protection line, voltage is small, only the voltage high frequency oscillation; after the installation of lightning arrester, the former two kinds of situation of lightning overvoltage amplitude can be effectively suppressed and, over voltage duration was greatly reduced, can improve the accuracy of relay protection action, lightning arrester installation can effectively reduce the substation outage rate, when the lightning protection line than lightning contact line and feeder caused by tripping rate is low, so can raise the height of line protection, shielding of other wires and has a certain guiding significance in engineering.