地铁杂散电流影响下的地表电位计算及敏感性因素分析

Calculation of surface potential and analysis of sensitivity factors under the influence of stray current in metro systems

为研究地铁杂散电流对交流电网的侵入范围和程度,根据实际运行下走行轨绝缘扣件的绝缘能力退化情况,建立杂散电流数学模型,推导得到每个轨枕泄漏的杂散电流。将地铁杂散电流离散为轨枕个数的有限点电流源,利用复镜像法求解格林函数的理论方法,建立地铁杂散电流引起地电位分布计算模型,并通过基于边界元法的商用接地软件CDEGS验证所提方法的准确性。讨论杂散电流泄漏量和土壤结构此类传统敏感性因素对城轨沿线地电位分布的影响,以及多线路交汇的交通枢纽地段多列车运行下的周围地电位波动情况。

In order to study the intrusion range and degree of subway stray current into the AC power grid,a mathematical model of stray current which is based on the degradation of insulation performance of rail insulation fasteners under actual operation is established,and the stray current leakage of each sleeper is derived.The subway stray current is discretized into a finite point current source according to the number of sleepers,and the Green's function is solved based on the complex image method.The ground potential distribution calculation model caused by the subway stray current is also established,and the commercial grounding software CDEGS based on the boundary element is deployed to verify the method accuracy.The influence of traditional sensitive factors,such as stray current leakage and soil structure,on the ground potential distribution along the urban rail line and the surrounding ground potential fluctuations under the operation of multiple trains in a multi-line transportation hub area are discussed.