雷击接触网高速动车组的车体过电压分析及抑制措施

Analysis and Repressive Methods of High-speed EMU Carriage Overvoltage Caused by Lightning Strike on Catenary

我国高速铁路采用大跨度高架桥结构,接触网离地面较高,容易遭受雷击进而引发动车组故障,给列车安全运行带来隐患,因此有必要探究雷击接触网时高速动车组车体过电压及其抑制措施。本文基于接触网电气模型和高速动车组电路结构,利用Pspice建立雷击接触网时车体过电压仿真模型,定量分析车体接地电阻参数对过电压的影响,提出抑制过电压的措施。仿真结果表明:雷击接触网时,受电弓所在的车体过电压幅值可达43.45kV,距离受电弓越远车体过电压越低;接地电阻器的分布电感对各车体过电压影响较大,且与车体所在位置有关,对距离受电弓越近的车体,影响越大。将2~5车的接地方式改为直接接地方式或电阻器并联电容的方式均能有效抑制车体过电压,且当并联的电容值大于10μF时,二者对过电压幅值的抑制程度基本一致,并在电阻器并联电容的基础上,通过减少接地电缆长度能够进一步降低车体过电压,将各车体过电压抑制在2kV以内。本文研究结果为车体过电压的进一步分析提供了理论依据。

The catenary on long span viaduct of high speed railway in China,which is conspicuously high from the ground,is particularly vulnerable to lightning strikes,which may lead to EMU failures.Therefore,it is necessary to study the overvoltage of carriages in EMUs when the lightning strikes the catenary and its suppression method.Based on the electrical model of the catenary and the structure of EMU circuit,an overvoltage simulation model in the situation of lighting striking the catenary was built by software Pspice to quantitatively analyze the influence of the carriage grounding resistor on the overvoltage and to propose the suppression methods.The simulation results show that the over-voltage amplitude of the 3 rd carriage where the pantograph is located can reach to 43.45 kV when lightning strikes the catenary.The value of over-voltage decreases with the increase of the distance between the carriage and pantograph.The carriage over-voltage,which is seriously influenced by the inductance of grounding resistor,is related to the position of the vehicle.The greater the impact of overvoltage on the carriage,the closer it is to the pantograph.Changing the grounding mode of2 nd-5 th carriages to direct grounding way or the parallel capacitor with the grounding resistor can effectively inhibit the carriage overvoltage.Especially when the parallel capacitor is greater than 10μF,the inhibition extent of both grounding modes to carriage over-voltage is consistent.Based on this,each carriage overvoltage can be suppressed within 2 kV by reducing the length of the grounding cable.The results of this study provide a theoretical basis for further analysis of carriage over-voltage.