基于长短时窗事件检测的电力电缆局放在线定位方法

On-line Partial Discharge Localization of Power Cable Based on Long-short Time Window Detection

在以高频电流法结合行波法为基础的电缆局部放电在线定位中,局部放电脉冲初至时刻的拾取是影响局部放电源定位精度的关键。针对现有方法易拾取伪脉冲的问题,提出一种长短时窗能量均值比结合变时窗峰度的局部放电在线精确定位方法。首先,采用长短时窗能量均值比进行局放事件检测,搜寻局放脉冲所在时窗;然后,根据确定的时窗数据绘制其变时窗峰度曲线,曲线的最大值点对应局部放电脉冲的初至时刻;最后,根据多传感器法对局部放电源进行定位。仿真实验结果验证了所提方法的有效性,同时,现场实测局放信号的实验结果表明,该定位方法能够在实际应用环境下准确拾取局放初至脉冲,具有工程应用价值。

In the on-line localization of partial discharge based on the high-frequency current method combined with the traveling wave method,the arrival time of the partial discharge(PD)pulse is the key to affect the positioning accuracy of the local discharge source.On the basis of this,a new method for accurate on-line localization of partial discharge with time-window energy mean ratio and time-window kurtosis is proposed in this paper.Firstly,the time window energy mean ratio is used to determine the time window of PD pulse;Then draw the curve of its variable time window kurtosis according to the determined time window data,the maximum point of the curve corresponds to the initial arrival time of the PD pulse;finally,the PD source is located according to the multi-sensor method.Simulation experiment is used to analyze the method under different window length,cable length and SNR.According to the pickup results of the first arrival time of the measured local discharge signal,the positioning method described in this paper has practical application value.