轨道交通杂散电流动态波动特性分析及其统计方法研究
Analysis of Dynamic Fluctuation Characteristics of Stray Current in Rail Transit and Research on Its Statistical Methods

城市轨道交通杂散电流流入城市电网接地的变压器绕组，造成了变压器的直流偏磁现象，进而影响变压器甚至是电网的安全稳定运行。针对这一现象，通过大规模实地监测，对某华东超大城市的500 kV及220 kV共计11个变电站的直流偏磁监测数据进行分析，通过对比轨道列车运行特性，总结分析杂散电流的动态波动特性。结果表明变压器杂散电流的动态特性与城市轨道交通列车的运行特性密切相关，具有较为明显的波动性、间歇性以及周期性。通过分析杂散电流的地理信息分布及其相关的电网结构，以及其正负占比特性，归纳出杂散电流在城市电网关于吸收、传播及散布的电路原理。最后，基于杂散电流连续监测数据，提出相应的统计方法。
The stray current of urban rail transit flows into the grounded transformer winding of the urban power network, resulting in the DC magnetic bias of the transformer, which affects the safe and stable operation of the transformer and even the power grid. In view of this phenomenon, through large-scale field monitoring, the DC magnetic bias monitoring data of 11 substations of 500 kV and 220 kV in East China’s megacity are analyzed. By comparing the operation characteristics of rail trains, the dynamic fluctuation characteristics of stray current are summarized and analyzed. The results show that the dynamic characteristics of transformer stray current are closely related to the operation characteristics of the trains of urban rail transit, with obvious volatility, intermittency and periodicity. By analyzing the geographic information distribution of stray current and its related power grid structure, as well as its positive and negative proportion characteristics, the electrical circuit principles about the urban power grid’s absorption, propagation and dispersion of the stray current are obtained. Finally, based on the continuous monitoring data of stray current, the corresponding statistical method is proposed.