城市轨道交通杂散电流对500 kV变压器直流偏磁影响测试分析

Test and Analysis on Influence of Stray Current of Urban Rail Transit on DC Bias of 500 kV Transformer

城市轨道交通运行会引起变压器直流偏磁问题,严重威胁电网的安全稳定运行。为研究轨道交通运行对变压器直流偏磁的影响,文中对上海市轨道交通沿线的某500 kV变压器,采用多物理量同步测量方法测试了轨道交通正常运行、高峰运行和停运后的变压器中性点直流、振动和噪声特性,并与2010年地铁刚投运时振动噪声数据进行比较。分析测试结果发现变压器中性点直流、振动噪声特性与轨道交通负荷功率呈现正相关的变化规律。证明了轨道交通运行引起的杂散电流会导致变压器长期直流偏磁运行,为解决类似问题提供了参考性意见。

The operation of urban rail transit will cause DC bias of transformer,which will seriously threaten the safe and stable operation of the power grid.In order to study the influence of operation of rail transit on the DC bias of transformer,the multi⁃physical measurement method is adopted of certain 500 kV transformer along the line of Shang⁃hai rial transit to test the neutral point DC,vibration,and noise characteristics of the transformer during normal oper⁃ation,peak operation and shutdown of the transformer,and compare with the vibration noise data of the subway in op⁃eration in 2010.It is found by the analysis and test result that the neutral point DC,vibrationand noise characteristics of the transformer as well as the load power of the rail transit show a positive correlation.It proves that the stray cur⁃rent caused by rail transit operation will cause the transformer to operate with DC bias for a long time,which provides guidance for the operation and maintenance of the transformer.