基于时间反演技术的电力电缆局部放电定位方法

Partial Discharge Location for Power Cable Based on the Time Reversal Technique

时延估计与相速度的频变特性是影响电缆局部放电定位精度的主要原因。该文提出了一种基于时间反演技术的电力电缆局部放电定位方法,该方法无需直接对局放时延进行估计并考虑了相速度的频变特性。通过双指数局放模型模拟实际局放信号,考虑了不同传输距离、不同信噪比、不同量化误差以及不同采样率对定位精度的影响,验证了该方法的可行性。最后利用振荡波局部放电测试系统对实验室一条长为498m的10kV XLPE电缆中的半导电层搭接不良缺陷进行了局部放电测试试验,考虑了2种不同类型的局放波形,并利用不同方法对2种不同类型的局放信号进行定位,验证了该方法的有效性和准确性。结果表明,该方法相比于传统的峰值法、相关法以及能量法都具有更高的定位精度。

Time delay estimation and frequency-dependent characteristics of phase velocity of power cables are main factors for precisely partial discharge location. This paper presents a partial discharge location method for power cables based on the time reversal technique which needn＇t estimate the time delay directly and takes the frequency-dependent characteristic of phase velocity into account. In the simulation test, a double-exponential function was built to simulate the partial discharge, and the feasibility was verified under different distances, signal to noise ratio, quantification errors, and sampling rates. Finally, the location validity and accuracy were verified by partial discharge test experiments performed on a 498m 10kV XLPE power cable using an oscillation wave test system. The results show that： the method can locate the partial discharge sources precisely and has a higher location accuracy compared with the traditional peak method, the correlation method and the energy method.