10kV系统工频弧光接地过电压的研究

Research on Power Frequency Arc Grounding Overvoltage of 10 kV System

弧光接地过电压是中性点不接地系统中危害最大的过电压之一。对弧光接地过电压的产生机理进行了深入研究,以某变电站10 kV电网为例,利用EMTP对中性点不接地和中性点经小电阻接地两种情况下的工频弧光接地过电压进行了仿真,并探讨了中性点经小电阻接地方式下工频弧光接地过电压的主要影响因素。分析和比较结果表明,中性点经小电阻接地方式可以降低不接地方式中的工频弧光接地过电压,从而降低绝缘水平的要求;合理地选择参数的数值,将可以更有效地限制甚至避免工频弧光接地过电压的产生。

The arc grounding voltage is one of the worst over-voltages in the non-ground neutral system. This paper his a deep study on the production mechanism of the arc grounding over-voltage and simulates the power frequency arc grounding overvoltages in the cases of both the neutral isolated and neutral grounded through low resistance with the EMTP,based on a substation 10kv network. The influence of different magnitude of resist- ance on the power frequency arc grounding overvoltage in the mode of neutral grounded through low resistance is also presented here. Simulation studies show that neutral grounded through low resistance can lower the pow- er frequency arc grounding overvoltage under different operating modes, therefore lower the requirement of in- sulation level. Proper parameters can effectively limit or even eliminate the arc grounding overvoltage.