基于高速列车接地系统参数对车体电流及过电压平衡的优化

Optimization of Vehicle Body Current and Overvoltage Balance Based on Grounding System Parameters of High Speed Train

由于高速列车的不断提速,接地系统迎来了全新的挑战。当列车与轨道之间发生相对运动时会产生加剧接地回流现象,导致列车车体电位升高,造成轴承和接地碳刷、绝缘节、车载传感器等异常甚至损坏等问题。针对目前高速列车存在的接地回流和车体电位的问题以及高速列车接地系统二维模型无法基于径向参数的基础上对同一车轴左右两侧电位进行仿真分析等存在的不足,当前有必要对高速列车综合接地系统进行更为完善的三维建模,并对接地系统的接地方式和接地参数等进行优化分析,以达到抑制接地电流和降低车体电位的目的。首先,基于RCL测试仪对车体的阻抗和感抗参数以及车体尺寸实际参数等实测数据及理论分析,在充分考虑各方面影响因素的前提下,分别从牵引变压器、接触网以及高速列车车载变压器、高压电缆、车体等方面,完成了高速列车综合接地系统三维电路模型的构建;同时,结合列车经过吸上线工况下的动态接地回流试验与高速列车升弓和闭合VCB的静态过电压测试试验,将仿真结果同实测结果进行对比,验证了三维模型的可靠性;最后,基于三维仿真模型,对接地系统的径向参数及保护接地和工作接地的三维分布进行优化设计,优化后,流过列车各保护接地的接地电流均有不同程度的降低,分布更加均匀,同时车体电位也在安全限值内。

Due to the increasing speed of high-speed trains,the grounding system faces new challenges.When the relative motion between the train and the track occurs,the phenomenon of ground backflow will be intensified,resulting in the rise of train body potential,the abnormity or even damage of bearing and ground carbon brush,insulation joint,on-board sensors and other problems.In view of the existing problems of grounding reflux and train body potential of high-speed trains and the failure of twodimensional model of high-speed train grounding system to simulate and analyze the potential of the left and right sides of the same axle based on radial parameters,it is necessary to conduct a more perfect three-dimensional modeling of the integrated grounding system of high-speed trains.In order to suppress the grounding current and reduce the potential of the vehicle body,optimized analysis of the grounding mode and grounding parameters of the grounding system is conducted.In this paper,based on the measured data and theoretical analysis of the impedance and inductance parameters of the train body as well as the actual size parameters of the train body by the RCL tester,the three-dimensional circuit model of the integrated grounding system of the high-speed train is completed respectively from the aspects of traction transformer,overhead contact line,on-board transformer of high-speed train,high-voltage cable and train body under the premise of fully considering all the influencing factors.At the same time,combined with the dynamic grounding reflux test of the train passing under the on-line condition and the static overvoltage test of the high-speed train raising the pantograph and closing the VCB,the simulation results are compared with the measured results to verify the reliability of the three-dimensional model.Finally,based on the threedimensional simulation model,the radial parameters of the docking system and the three-dimensional distribution of the protection grounding and working grounding are optimized.After optimization,the ground current flowing through the protection grounding of the train is reduced to different degrees,and the distribution becomes more uniform.Meanwhile,the potential of the train body is maintained within the safety limit.