小电阻接地系统间歇性弧光过电压分析

摘要

利用PSCAD/EMTDC软件建立了中性点经小电阻接地系统的仿真平台,使用接地电弧模型模拟间歇性电弧接地故障,并结合工频熄弧理论分析弧光过电压的产生情况.首先分析中性点不接地系统发生间歇性电弧接地故障时弧光过电压的情况,通过仿真证实这种接地方式容易发生弧光过电压；然后分析在中性点经小电阻接地系统中两种间歇性电弧接地故障引起过电压的情况.最后得出结论:中性点经小电阻接地方式可以较好地抑制间歇性弧光接地过电压的产生.%A simulation platform about the low resistance grounded system, where the grounded arc model is used to simulate the intermittent arc earth fault, is constructed by the use of the PSCAD/EMTDC in this paper. The arc extinction theory of power frequency is applied to analyze the principle of overvoltage. Firstly, arc overvottages in the isolated neutral system are presented and verified that the overvoltages easily happen when the intermittent arc earth fault occurs by simulations. Secondly, two kinds of intermittent arc earth fault in the low resistance grounded system are analyzed. Finally, the conclusion is obtained that the low resistance grounded system can effectively suppress the overvoltage.