高速列车接地系统对车体电流及过电压分布的影响分析

Analysis of the Influence of High-speed Train Grounding System on the Rail Circulation and the Overvoltage Distribution of the Train Body

高速列车独特的轮轨耦合移动接地系统在其行车安全方面起到关键作用,不合理的接地设置无法有效降低车体暂态过电压幅值,会造成设备绝缘击穿,同时,窜入车体的环流会恶化车载设备、轴承的电磁环境,车载设备与人员安全也需要得到充分保障。因此,对高速列车的移动接地系统性能研究,需要兼顾接地电流与车体过电压两项重要指标进行优化改进,服务于提升动车组长期的服役性能。以吸上线区间和电分相区间的“车-所-网”供电和回流系统为例,对动车组车载设备进行参数测量,对“车-所-网”供电系统进行等值计算。基于车载关键设备的实测阻抗参数,构建“车-轨-网”牵引供电系统的等效电路模型,研究车载牵引供电系统高压侧操作过电压特性以及车体过电压的传播规律,解析列车接地系统对车轨环流及车体过电压分布的影响机制,并结合接地回流及车体过电压两方面指标,对比不同接地阻抗参数及布局方式对车体过电压与车轨环流的影响规律。最终,获得一套基于调整电阻、电感以及接地方式的平衡了电压与电流的优化方案。

The unique wheel-rail coupling mobile grounding system of high-speed trains plays a key role in safety and unreasonable grounding settings cant effectively reduce the transient overvoltage amplitude of the train body,which will cause equipment insulation breakdown.At the same time,the current intruding the car body will deteriorate the electromagnetic environment of on-board equipment and the safety of on-board equipment and passengers needs to be fully guaranteed.Therefore,the research on the performance of the mobile grounding system of high-speed trains should also focus on optimizing and improving the two important indicators of grounding current and train body overvoltage to improve the long-term service performance of EMUs.In this paper,taking the“vehicle-institute-grid”power supply and return system between the suction line interval and the electric phase division interval as an example,the parameters of the on-board equipment of the EMU are measured,and the equivalent calculation of the“train-substation-catenary”power supply system is carried out.Based on the measured impedance parameters of on-board key equipment,the equivalent circuit model of the“vehicle-rail-network”traction power supply system is constructed,the characteristics of the operating overvoltage on the first side of the on-board traction power supply system and the propagation law of the overvoltage of the vehicle body are studied,the influence mechanism of the train grounding system on the distribution of rail circulation and train body overvoltage is analyzed,and the influence of different grounding impedance parameters and layout methods on the overvoltage and rail circulation of the train body is compared.Finally,an optimized scheme that balances voltage and current based on adjusting resistance,inductance and grounding layout is obtained.