特高压直流接地极入地电流对高速动车组影响分析

Impact of Ground Current of HVDC Earth Electrode on High-speed EMU

直流输电系统以大地为回路运行时,在地中形成的电流场会对邻近的多点分散接地的高速铁路系统产生影响。文章建立完整的高速铁路综合接地等效模型和高速动车组电气模型,分析其中存在的直流通路,提取适用于高速铁路仿真建模的"Π"型等效电路,在此基础上,利用CDEGS软件建立高速铁路各典型场景的仿真模型,通过对不同土壤电阻率、接地极距铁路的垂直距离等维度仿真分析,比较了不同外部条件下流过牵引供电系统和动车组的直流电流。结果表明,不同高铁工程段直流参数存在差异,土壤电阻率越高,接地极距铁路垂直距离越小,流过动车组牵引变压器的直流电流越大;当沿线土壤电阻率小于300Ω·m,并且接地极距离铁路垂直距离超过5 km时动车组牵引变压器直流偏磁影响满足规程要求。

During the operation of HVDC system with the earth as the loop,the formed current field in the ground has corrosion effect on the adjacent high-speed railway system.A complete high-speed railway comprehensive grounding equivalent model and high-speed EMU electrical model were established,the existing DC path was analyzed,and the"Π"type equivalent circuit suitable for high-speed railway simulation modeling was extracted.The simulation models of various typical scenes of high-speed railway were established by using CDEGS software.Through the simulation analysis of different soil resistivity and vertical distance between grounding electrode and railway,the DC current flowing through traction power supply system and EMU under different external conditions was compared.The results show that there are differences in DC parameters in different high-speed railway sections.The higher the soil resistivity,the smaller the vertical distance between the grounding electrode and the railway,and the greater the DC current flowing through the traction transformer of EMU;When the soil resistivity along the line is less than 300Ω·m and the vertical distance between the grounding electrode and the railway is more than 5 km,the DC magnetic bias effect of EMU traction transformer meets the requirements of the regulations.