高速铁路电分相中性段网压抬升机理及抑制措施研究

Research on the Mechanism and Suppression Measures of Voltage Rising in the Phase Split Neutral Section of the High-Speed Railway

高速铁路牵引供电系统负荷功率大、取流时间长,其电分相中性段由于电磁耦合会产生较高的感应电压。且列车通过电分相中性段时,由于车-网电气拓扑结构瞬变可能会激发铁磁谐振过电压,引起中性段网压抬升,威胁行车安全。本文从电磁感应和铁磁谐振两方面对中性段网压抬升机理进行分析,并建立仿真模型进行验证。结果表明:电分相中性段的感应电压会随供电臂两端相位差的增大逐渐减小,呈现明显的容性耦合特征;电分相两端相位差处于0°~180°和180°~360°时,中性段铁磁谐振电压先增大后减小且在90°和270°左右达到最大;车顶电压互感器和中性段对地电容参数是引起车-网铁磁谐振的关键点,中性段并联RLC保护装置能有效抑制中性段铁磁谐振过电压。

The high-speed railway traction power supply system generally runs under large load power and long current taking time,and its phase split neutral section can generate high induced voltage due to electromagnetic coupling.Moreover,when the train running through the neutral section of the phase splits,the transient changes in the train-catenary electrical topology may excite the ferromagnetic resonance overvoltage and cause the neutral section network voltage rise,which could threaten driving safety.This paper analyzed the mechanism of the voltage rise of the neutral section catenary from the aspects of electromagnetic induction and ferromagnetic resonance,and it was valid by a simulation model.The experiment results showed that the induced voltage of the neutral section of the electric split will gradually decrease with the increasing of phase difference between two ends of the power supply arms,and the induced voltage showed obviously capacitive coupling characteristics;when the phase difference at both ends of the electric phase is 0°to 180°and 180°to 360°,for ferromagnetic resonance voltage of the neutral section,it increased initially and then decreased,and finally reached to maximum around 90°to 270°.The roof voltage transformer and the neutral section’s capacitance to ground were the key point which cause train-catenary ferromagnetic resonance,and the neutral section parallel RLC protection device could effectively suppress the neutral section ferromagnetic resonance overvoltage.