地铁杂散电流对变压器直流偏磁的影响分析  

Analysis of the influence of metro stray current on transformer DC bias

作　　者：周展帆 严宇 于艺盛 倪砚茹 程新翔 喻锟 曾祥君[3] 唐雨杭 ZHOU Zhanfan;YAN Yu;YU Yisheng;NI Yanru;CHENG Xinxiang;YU Kun;ZENG Xiangjun;TANG Yuhang(State Grid Hunan Extra High Voltage Substation Company,Changsha 410004,China;Substation Intelligent Operation and Inspection Laboratory of State Grid Hunan Electric Power Co.,Ltd.,Changsha 410004,China;School of Electrical&Information Engineering,Changsha University of Science&Technology,Changsha 410114,China)

机构地区：[1]国网湖南省电力有限公司超高压变电公司,湖南长沙410004 [2]变电智能运检国网湖南省电力有限公司实验室,湖南长沙410004 [3]长沙理工大学电气与信息工程学院,湖南长沙410114

出　　处：《电力科学与技术学报》2024年第1期134-143,共10页Journal of Electric Power Science And Technology

基　　金：国网湖南省电力有限公司科技项目(164100003187)。

摘　　要：地铁运行过程中泄漏的杂散电流引起地电位波动变化,易导致附近接地变压器出现直流偏磁现象。为解决此类问题,首先,建立了地铁运行等值电阻网络模型,实现杂散电流实时数值计算;然后,进一步推导了杂散电流场位方程,实现地铁机车运行时附近大地电位空间分布的动态模拟;最后,基于杂散电流引起的大地电位分布结果与交流电网的等效直流电阻模型,实现接地变压器偏磁直流和励磁电流的数值计算,建立中性点直流量和波形畸变率偏移度评判指标,可有效评估变压器直流偏磁程度。仿真结果表明,机车运行工况及机车间距对变压器直流偏磁影响明显,制定合理的地铁运行策略可有效削弱附近变电站直流偏磁干扰。The metro stray current leaked during the train operation causes the surface potential fluctuation,resulting nearby transformer DC bias.Firstly,a equivalent resistance network model was established to realize actual time numerical calculation of stray current.Then,the stray current field equation was further derived,and the dynamic simulation of the geopotential potential distribution was realized during the train operation.Based on the potential distribution caused by stray current and the equivalent DC resistance model of AC power grid,the numerical calculation of DC bias current and excitation current of grounding transformer was realized.The index of neutral point current and waveform distortion rate is established,so the effective evaluation of the transformer DC bias could be realized.The simulation results show that the operating conditions and distance between the metro train have obvious effects on the transformer DC bias,so formulating a reasonable metro operation strategy could effectively restrain transformer DC bias interference for nearby substations.

关 键 词：地铁 杂散电流 地表电位 变压器直流偏磁 变压器中性点电流 

分 类 号：TM401.1[电气工程—电器]