基于零序电流幅值连调的小电流接地系统故障区段定位方法

为提高小电流接地系统中利用故障稳态特征实现故障定位方法的准确率和抗过渡电阻能力,提出基于零序电流幅值连调的单相接地故障区段定位方法。通过注入信号逐次调控中性点电压,结合各检测区段零序电流特征与过渡电阻、调控系数大小的关系,确定调控范围。不同程度地放大故障特征,获取零序电流幅值稳态量。通过叠加特征增强量与设定阈值比较,从而定位故障区段,并根据零序电流特征的变化趋势实现高阻故障区段判别。仿真结果表明该方法对于不同过渡电阻值均能准确定位故障区段,具有较强的适用性。

Fault location method of a non-effective earthed system based on zero sequence current amplitude continuous regulation

To improve the accuracy of fault location based on a steady-state feature and its resistance to transition resistance in a non-effective earthed system, a fault location method based on amplitude continuous regulation of zero sequence current is proposed. The injected signal is used to flexibly adjust the neutral voltage. Based on the test section of zero sequence current characteristic and the transition resistance, and the size of the adjustment coefficient of relationship, the scope of the regulation is determined. The steady-state amplitude can be obtained by amplifying fault features to different degrees. By superimposing the feature enhancement and comparing with the set threshold value, the fault section is located and the high-resistance fault section is identified according to the variation trend of zero-sequence current characteristics. The simulation shows that this method can eliminate the impact of a false zero-sequence amplitude component caused by three-phase imbalance, and can accurately locate the fault section for different transition resistances, and has strong applicability. This work is supported by the National Natural Science Foundation of China (No. 51737002) and the Changsha Science and Technology Project (No. kh1901140).