变电站站内短路情况下避雷线分流系数计算

Computation of Shunt Coefficient of Grounding Grid under Short-Circuit Fault Occurred within Substation

在对发电厂和变电站的接地网进行设计时,需要对入地故障电流进行校验,而避雷线分流系数是确定接地网目标电流的基础数据。目前,接地设计规程仅给出了每个档距内导线参数和杆塔接地电阻相同的情况下分流系数的计算方法,当出线各级杆塔接地电阻不同时,无法准确计算避雷线分流系数。本文以变电站站内短路情况为例,给出基于图论的回路电流法计算避雷线分流系数的模型和方法。通过与实测数据比较表明本文计算方法计算精度较高,且采用矩阵形式,易于编程实现和推广应用于更复杂的多电源供电变电站。

In designing of the grounding grid of power station and substation,the earth diffusing short-circuit fault current need to be checked,and the shunt coefficient of grounding grid is a fundamental data.Considering the short-circuit fault occurred within substation,a computing method based graph theory andloop current method of shunt has been given in this paper.By comparing with the date from actual testand order component method show that the method used in this paper could obtain high precision.The relationship between ground potential rise and substation grounding resistance has been studied,which couldprovide a reference for designing of the power station and substation.