XLPE电缆终端绝缘气隙缺陷的局部放电烧蚀特征

Partial Discharge and Ablation Characteristics of Air Gap Defects in XLPE Cable Termination Insulation

为研究气隙缺陷导致交联聚乙烯(XLPE)电缆终端绝缘破坏的机理,对内部设置气隙缺陷的XLPE电缆终端进行电热老化实验与局部放电(PD)检测实验,并通过扫描电镜(SEM)和能谱仪(EDS)分析老化前后气隙的表面形态及元素组成。结果表明:XLPE电缆终端绝缘内部的气隙缺陷在运行条件下PD迅速发展并表现出显著的阶段性特征,气隙通道的快速击穿与气隙接触点周围的气孔受电场应力作用而扩张的关系密切,接触点经放电烧蚀逐渐形成碳颗粒。

In order to investigate the insulation failure of XLPE cable termination caused by air gapdefects, we carried out electrical-thermal ageing experiments and partial discharge tests for the XLPEcable termination with air gap defects. The surface morphology and element composition of the air gapwere analyzed by Scanning Electron Microscope（SEM） and Energy Dispersive Spectrometer（EDS） beforeand after ageing experiments. The results show that the partial discharge of the air gap defects developsrapidly under working condition and shows stage characteristics obviously. The breakdown of dischargechannel is closely related to that the gas pore around contact points of the air gaps would expand underthe effect of electric field stress. The contact points gradually turn to carbon particles during the processof discharge ablation.