基于解析法的架空地线感应电流分布特性分析

Analysis of Induction Current Distribution on Overhead Ground Wires Based on Analytic Method

针对架空地线感应电流的沿线分布进行分析,指出可在梯形网络的首尾两端各加1个电压源来等效杆塔对地电压,感应电流整体呈两端小、中间段大的“n”字形分布。通过解析法直接推导出感应电流的上限值,其大小仅与单位长度地线的感应电压和阻抗有关。结合理论推导与MATLAB/Simulink仿真计算,对比2种常见接地方式下的地线感应电流,发现一侧逐基接地、一侧分段接地的节能接地技术虽然能有效减少能量损耗,但不能降低感应电流的峰值。对导线换位、地线故障这2种特殊情况下感应电流分布的分析表明:导线换位时,地线电流整体减小;接触不良故障时,不仅可能引起故障点异常发热,还会在附近产生多个发热点。

In view of the distribution of induction current along the overhead ground wires,this paper carries out analysis and proposes to add the voltage source respectively at each end of the trapezoidal network to equalize the grounding voltage of the tower.It points out that the distribution of induction current presents“n”pattern with small end and large middle section.By means of the analytic method,it directly deduces the upper limit value of induction current,which is only related to the induction voltage and impedance of per unit length of the ground wire.Combining the theoretical derivation and MATLAB/Simulink simulation,the paper compares the induction current of ground wire under two common grounding modes and discovers that though the energy-saving grounding technology of one-side grounding by one side and one side grounding by sections can effectively reduce energy losses,it cannot reduce the peak of induction current.It also analyzes the distribution of induction current in two special cases of traverse transposition and ground wire fault.The result indicates that the ground wire current decreases as a whole when the traverse transposition occurs,while poor contact failure may cause abnormal heating of the fault point and generate multiple heating points nearby.