基于电网络理论的变电站接地网腐蚀及断点诊断方法

摘要

变电站接地网埋设在地下,因土壤的长期作用而造成腐蚀,导致其接地性能变坏,威胁着电力系统的安全稳定运行。本文将变电站接地网近似等效成纯电阻网络,根据接地网的拓扑结构和接地引线间电压的测量数据,推导端口电阻值,建立基于特勒根定理的接地网故障诊断方程,借助优化方法求解该诊断方程得到接地网各支路电阻的变化值,进而判断接地网的腐蚀程度,找到故障所在位置。通过仿真计算和模拟接地网的故障诊断实验,验证了本文接地网故障诊断方法的有效性和实用性。%The grounding grid of substation is buried under the ground.The soil acid and alkali induce the grid corrosion,which leads to the grounding performance deteriorated and threatens the safety operation of the power system.In this paper,the grounding grid is treated as a pure resistance network.By using the actual ground grid topology and the measured voltages between grounding leads and the ground,the fault diagnosis equations are built base on the Tellegen theorem.By means of optimization methods solving the fault diagnosis equations the resistance changes in the each branch are obtained,and the corrosion degree of grounding grid is judged,and then the position of the fault is found.Through comparing the results calculated and measured,the practicality of diagnosis method of grounding grids is verified.