高压交联电缆接头局部放电的电容耦合法检测及分析

Capacitive Coupling Detection and Characteristic Analysis of Partial Discharge in High-voltage XLPE Power Cable Joints

为研究110kV交联电缆接内部绝缘缺陷的局部放电(partial discharge,PD)特性,设计并构造了5种典型绝缘缺陷,通过建立电缆接头局放试验研究平台,采用电容耦合法获取不同绝缘缺陷下的放电信号,构造出三维PRPD(phase resolved partial discharge)谱图表征缺陷放电状态,并采用单次放电脉冲时域波形的3、4阶特征参量萃取放电特性进行分析。研究试验结果显示,电容耦合法检测法可有效检测出电缆接头内部缺陷引起的局放,且不影响电缆接头及本体的绝缘性能;所构建的5种典型缺陷在工频电压激励下,放电脉冲序列在放电区间、放电重复率等统计特征有很大的不同,用时域波形的3、4阶特征参量所描述的放电特性也存在很大差异。这些特征可用作放电类型识别的依据。

Five models of typical internal insulation defects are designed and a test platform for partial discharge （PD） research on cable accessories also is constructed in order to study PD characteristics of internal insulation defects in 110 kV XLPE cable joints. By use of capacitive coupling method, plenty of PD data are obtained for various models and the construction of related phase-resolved PD diagrams. Based on the third-order and fourth-order characteristic parameters, discharge characteristic analysis of a single pulse current is presented. The experimental re sults show that capacitive coupling method is effective for detecting PD signals from internal defects of cable joints without harmful influence on insulation properties of cables and cable joints. In addition, there are significant differences in the some statistical parameters （e. g. , discharge interval, discharge repetition rate）of PRPD （ phase resolved partial discharge） diagrams and the third order and fourth-order characteristic parameters of time domain PD wave form which can be used as reference points for PD patterns.