小电流接地系统单相接地故障的小波选线方法

WAVELET LINE SELECTION METHOD FOR SINGLE-PHASE GROUDING FAULT IN SMALL CURRENT GROUNDING SYSTEM

为了研究小电流接地系统单相接地故障的选线问题,本文提出了基于暂态量的小波分析法。故障电流中暂态信息量可被利用的有效成分较多,利用小波变换对信号的精确分析,通过比较各条线路故障零序电流经小波变换后信号的模极大值大小以及极性来实现故障选线。本文利用MATLAB建立了中性点经消弧线圈接地系统的仿真模型并进行了相电压峰值、过零时刻以及母线故障的仿真试验,结果表明故障时间、接地电阻、故障长度都影响不了小波方法选线的准确性。

In order to study the problem of single-phase grounding fault line selection in the small current grounding system,a wavelet analysis method based on transient variables was proposed in this paper.There were many effective components that could be used in the transient information in the fault current.The wavelet transform was used to accurately analyze signals,the fault line selection was realized by comparing the module maximum value and polarity of signal zero sequence current after the wavelet transform.In this paper,a simulation model of the neutral grounding system with grounding through the arc was built by the MATLAB software,and a lot of simulation experiments were carried out.The results showed that the fault time,earthing resistance,and fault length could not affect the accuracy of the line selection by the wavelet method.