基于Bhattacharyya距离的小电流接地故障选线

Fault Line Selection of Small Current Grounding System Based on Bhattacharyya Distance

提出一种基于Bhattacharyya距离测度零序电流相似性的配电网小电流接地系统故障选线方法,克服小波变换等暂态选线方法存在的难以确定能量频段的问题。通过对不同故障条件下小电流接地系统零序电流分析,发现故障后半个周波内故障线路和非故障线路的暂态波形相似度很低,而非故障线路之间的相似度很高。为此,提出了采用Bhattacharyya距离作为度量零序电流相似性的配电网小电流接地系统故障选线判据。仿真结果表明,该方法容易实现,对采样频率要求不高,选线准确率和效率高,且不易受过渡电阻、故障初始条件差异等外界因素的干扰。

A fault line selection method for small current grounding system in distribution network based on Bhattacharyya distance measurement zero sequence current similarity is proposed.It overcomes the difficult problem of determining energy frequency band in transient line selection methods such as wavelet transform.By analyzing the zero-sequence current of the small current grounding system under different fault conditions,it is found that the transient waveform similarity between the faulty line and the non-faulty line in the half cycle after the fault is very low,and the similarity between the non-fault lines is very high.For this reason,the Bhattacharyya distance is used as the fault line selection criterion for the small current grounding system of distribution network using the similarity of zero sequence current.The simulation results show that the method is easy to implement.The sampling frequency is not high.The line selection accuracy and efficiency are high,and it is not easily interfered by external factors such as transition resistance and initial fault conditions.