市域列车接地回流动态变化规律分析与优化

Analysis and Optimization of Dynamic Variation Law of Grounding Return Current of Intercity Train

市域列车通过车体-轮对-钢轨形成接地回流通道,过大的接地回流会造成轴承电腐蚀、碳刷的异常磨耗等问题,严重威胁动车的安全运行。在Matlab/Simulink中建立了市域列车在供电区间内行驶时接地回流动态过程仿真模型,并结合现场测试数据验证了模型的准确性,探明了市域列车在供电区间内运行时接地电流的变化趋势。从接地电流热效应出发,提出市域列车接地电流的“等效值”的概念。从工作接地方式与保护接地方式两个方面出发,探究接地回流的影响因素。根据接地电流的等效值,提出市域列车接地系统的优化方案,仿真结果表明,优化后保护接地电流等效值由53 A下降到17 A,下降幅度达到67%,接地回流分布较为均匀,车体电位也控制在安全的范围内,为设计更优良的接地方案提供了理论基础。

The intercity train forms a grounding return channel through the body wheel set rail.Excessive grounding return will cause problems,such as electric corrosion of bearings and abnormal wear of carbon brushes,which seriously threatens the safe operation of the intercity train.The dynamic process simulation model of grounding return current of intercity train running in the power supply section is established in Matlab/Simulink.Combined with the field test data,the accuracy of the model is verified,and the change trend of grounding current of intercity train running in the power supply section is proved.Based on the thermal effect of grounding current,the concept of“equivalent value”of grounding current of intercity train is proposed.The influence of ground return is explored in terms of both working and protective grounding methods.According to the equivalent value of grounding current,the optimization scheme of intercity train grounding system is proposed.The simulation results show that after optimization,the equivalent value of protective grounding current is reduced from 53 A to 17 A,with a decrease range of 67%,the distribution of grounding return current is relatively uniform,and the vehicle body potential is also controlled within a safe range,which provides a theoretical basis for designing a better grounding scheme.