多判据融合小电流单相接地故障选线方法仿真

Multi-Criterion Fusion Small Current Single-Phase Ground Fault Line Selection Method Simulation

目前接地故障选线法的准确性和稳定性均较差,提出基于多判据融合的小电流单相接地故障选线方法。针对各条小电流单相接地线路零序电流信号实行小波变换操作,使不同尺度下的电流信号于一定时间内更趋近平稳,并使不同尺度下电流信号频谱能够集中分布。通过维纳滤波针对平滑信号或者细节信号实行滤波操作,完成小电流单向接地信号干扰滤波。分别利用零序有功分量方法和零序无功分量方法获取接地故障线路,并对两种方法的故障选线性能隶属度函数进行计算。通过主观Bayes法将两种方法进行多判据融合操作,得到故障选线结果置信度值,给出小电流单相接地故障线路判断结果。实验结果表明,上述方法故障选线准确性系数最高为0.97,稳定性较强。上述方法不仅具有高精度选线性能,还能够抑制故障选线中的干扰,稳定性较强。

This paper presents a line selection method for low current single - phase ground fault based on multi -criterion fusion. Firstly, the wavelet transform was applied to the zero sequence current signals in each low- cur- rent single - phase ground line to keep the current signals at different scales more stable. Meanwhile, the spectrum of current signals at different scales was distributed centrally. Then, wiener filtering was used for smooth signal or detail signal, and the interference filtering of low - current one - way ground signal was completed. Moreover, zero - se- quence active component method and zero - sequence reactive component method were used to obtain the ground fault line and the membership functions of fault line selection performance in two methods were calculated. The subjective Bayes method was used to fuse two methods based on multiple criteria so as to obtain the confidence value of fault line selection and give the judgment result of low - current single - phase ground fault line. Simulation results show that the proposed method has strong stability and the maximal accuracy coefficient of fault line selection is 0. 97. Meanwhile, this method not only has high - precision performance of line selection, but also can suppress interference in fault line selection.