中性点不接地系统单相漏电故障特征及选线判据

Characteristics and line selection criteria of single-phase leakage fault in neutral ungrounded system

从研究中性点不接地系统单相漏电故障机理分析入手,采用戴维南定理进行稳态分析,得到了发生故障时故障线路与非故障线路零序电压和零序电流之间的关系。基于零序功率方向原理计算出发生故障时的各支路之间的关系,最终得到选线判据。为了对理论分析结果的正确性进行验证,最后进行了极端情况下的分析,验证了等效电路和理论分析的正确性,并且验证了故障选线判据的选线准确性和普适性。

It starts with the analysis of single-phase leakage fault of neutral ungrounded system,and uses the Venin theorem for steady-state analysis,and obtains the relationship between zero sequence voltage and zero sequence current of fault line and non-fault line when fault occurs.Based on the principle of zero sequence power direction,the relationship between the branches when the fault occurs is calculated and the line selection criterion is finally obtained.In order to verify the correctness of the theoretical analysis results,the analysis in extreme cases was carried out in the end to verify the correctness of the equivalent circuit and the theoretical analysis,as well as the accuracy and universality of the fault line selection criteria.