局部放电信号在交联聚乙烯高压电力电缆中的衰变及其检测

Decay and Detection of Partial Discharge Signals in High-voltage Cross-linked Polyethylene Power Cable

针对高压交联聚乙烯电力电缆独特的分层半导电绝缘以及复杂的金属屏蔽结构,采用阻抗分布参数加权比的传输线简化模型以及时域有限差分法对局部放电脉冲在电缆及接头中的衰减谱特性进行理论计算和电磁场仿真分析。设计和构建了电力电缆接头典型物理绝缘缺陷模型以及3种不同类型传感器组合的局部放电检测系统,开展了复杂的高压电力电缆接头分层结构的远区场衰变试验和近区场传感器的检测特性研究,结果表明:局部放电波形幅值呈幂函数衰减,波形也发生严重畸变,验证理论计算及仿真结果,为交联聚乙烯高压电力电缆局部放电检测试验及故障诊断提供参考。

A simplified model of transmission line of impedance distributed parameter weighted ratio and finite difference time-domain method were used in the calculation and electromagnetic simulation analysis of the attenuation spectrum characteristics of PD pulse in cables and joints,for the distinctive multi-layered semi-conducting insulation and complex metal shielding structure of cross-linked polyethylene cable.Meanwhile,models of insulated defects in power cable joints and three kinds of sensors were designed.Experiments on near-field and far-field in PD detection system of power cable show that the amplitude of partial discharge wave is similar to power function,and the wave shape is distorted.There is a good match between finite difference time-domain results,calculation of model of transmission line and measurements,The results are helpful for the partial discharge detection and defects identification in cross-linked polyethylene high-voltage power cables.