Influence of grounding mode on surge voltage in the process of pantograph rising for high speed train

Surge voltage on the carriage which transports along high speed train occurs frequently in the process of pantograph rising, the surge voltage is likely to cause electromagnetic interference or logical confusion to vehicle control and communication system, and even damage the vehicle-mounted components. That maybe a potential threaten for normal operation of high speed train. And the amplitude of surge voltage varies with the change of the grounding mode. In order to study the surge voltage systematically, an equivalent circuit model was built in the process of pantograph rising based on the grounding mode of a certain-type high speed train. The mechanism and propagating characteristics of surge voltage were studied and the influence of different grounding modes on the surge voltage was analyzed in the process of pantograph rising. The results show that the grounding mode affects the carriage surge voltage significantly. The maximum amplitude of surge voltage reaches 4.85kV and rapidly decays in 15 μs in the original grounding mode, while it decreases to 2.4kV in direct grounding mode. However, the transient impulse voltage that the weak current system can withstand should not exceed 2kV. The surge voltage value can be effectively decreased by parallel connecting a capacitor with a grounding resistor. The amplitude of surge voltage relates to the value of the parallel capacitance, and the value of surge voltage will be reduced below 2kV when the value of capacitance is 10μF. The conclusions provide theoretical basis for studying the influence of grounding mode on surge voltage in the process of pantograph rising for high speed train.