基于时间反演相位法的电力电缆局部放电定位

Research on Partial Discharge Source Location for Power Cables Based on Time Reversal Phase Method

为解决传统时延估计法定位精度较低以及存在定位死区的问题,提出基于时间反演相位的电力电缆局部放电定位方法,不仅在定位精度上优于传统时延估计法,而且能够实现对电缆首末端局放源的准确定位。首先,利用MATLAB建立电力电缆频域模型,利用双指数脉冲模拟实际局放信号,并分别从仿真和实验的角度验证了该方法的可行性;然后,研究了不同信噪比、不同传输距离、不同量化误差以及不同采样率对定位精度的影响,并与传统时延估计法中最为常用的能量法和相关法作比较。最后,利用振荡波测试系统对259.2 m的10 kV XLPE电力电缆进行局部放电试验,验证了定位的有效性和准确性。结果表明,基于相位的时间反演法能够准确定位局放源的位置,并且能够解决传统时延估计方法中存在的定位死区问题。

In order to solve the problem of low accuracy and locating dead zone with traditional time delay estimation method,a power cable partial discharge location method based on time reversal phase is proposed.This method is superior to traditional time delay estimation method in location accuracy,and can realize accurate location of partial discharge source at cable terminals.Firstly,a frequency domain model of power cable is established with MATLAB,and the actual partial discharge signal is simulated using double exponential pulse,and feasibility of this method is verified from the perspectives of simulation and experiment respectively.Then,the effects of signal-to-noise ratio,propagation distance,quantization error and sampling rate on location accuracy are studied.Finally,validity and accuracy of the location method were verified with partial discharge tests,performed on a 259.2 m 10 k V XLPE power cable using oscillation wave test system.Results show that the time reversal phase method can locate the partial discharge source accurately and solve the problem of dead zone location in traditional time delay estimation method.