Study On Grounding Technology Of High-Speed Trains

High-speed railway has been vigorously developing in China due to its high speed, great transport capacity, high rate of punctuality, low energy consumption, little environmental impact, conservation of land and high security. Improvement of the technical capacity of EMU is urgent in order to enhance the level of high-speed railway business, and the optimization of EMU’s grounding system is one of the important issues.The high-speed train’s grounding system mainly consists of two parts, namely vehicle electrical equipment grounding system and body grounding system. Vehicle electrical equipment grounding system focuses on the high-voltage cable shield grounding type.And there are large differences in body grounding system because of different models of the EMUs. Grounding system is the vent channel of Lightning impulse or surge impact overvoltage. Consequently the reasonable grounding system can effectively improve the personal safety coefficient and vehicle electrical equipment safety factor.In this paper, the influence of the grounding system on the body voltage andcurrent with operating conditions of high speed train was studied.Namely the influence of the body grounding type or the high-voltage cable shield grounding type on the body voltage was analyzed. And the corresponding solutions were proposed. The specific content of the study includes the following two aspects.On the one hand, body grounding system was studied. At first,simulation models, based on Matlab/Simulink,was built. And the influence on body voltage and current with the change of grounding parameters had been analyzed in different working conditions, which includes normal condition or suffering lightning impulse. Then the influence of different body grounding parameters on body voltage and current was analyzed. Finally the best body grounding parameters was proposed.On the other hand, the high-voltage cable shield grounding type was analyzed. For one thing, the characteristic of overvoltage propogation in the high-voltage cable. The impact on body voltage and current with the different layout of grounding point of cable shield had been studied. Then the methods of limiting induced current on cable shield were proposed. The model of an equivalent circuit was established based on pantograph rising. Eventually the formation mechanism of Surge overvoltage at the moment of Rising Pantograph, and its restrained method were analyzed. Related experiment had been carried.