高压电力电缆绝缘屏蔽烧蚀机理分析及应对措施  

Ablation Mechanism Analysis and Countermeasures of Insulation Shielding of High Voltage Power Cable

作　　者：吴科 邓旭东 别桦 李昆晟 付强林 宋伟 WU Ke;DENG Xudong;BIE Hua;LI Kunsheng;FU Qianglin;SONG Wei(Maintenance Branch Company,State Grid Chongqing Electric Power Company,Chongqing 400039,China;Chongqing Urban Power Branch Company of State Grid,Chongqing 400010,China)

机构地区：[1]国网重庆市电力公司检修分公司,重庆400039 [2]国网重庆市电力公司市区供电分公司,重庆400010

出　　处：《绝缘材料》2020年第2期97-101,共5页Insulating Materials

摘　　要：高压电缆绝缘屏蔽烧蚀击穿是导致电缆故障频发的重要原因。为研究电缆绝缘屏蔽烧蚀机理,设计了110 kV电缆电-热协同试验平台,测试分析了不同电压下试验回路电流的变化规律,并对不同烧蚀时间下绝缘屏蔽的烧蚀损伤程度进行对比分析。结果表明:不同试验电压下试验回路电流存在明显差异。试验电压低于50 V时,电流增长缓慢趋近于零;试验电压高于50 V时,电流增加明显,更利于观察试验现象。绝缘屏蔽表面烧蚀面积和深度随烧蚀时间的延长而增加,在试验电压为120 V下持续放电720 h时,绝缘屏蔽层烧蚀面积和深度分别达到40 mm^2和1.8 mm。最后建立了电缆本体局部放电模型,发现绝缘屏蔽与铝护套间的气隙是导致绝缘屏蔽烧蚀击穿的重要原因,并对如何降低电势差提出了改进措施,有利于延长电缆使用寿命和提高运行可靠性。The ablation breakdown of high voltage cable insulation shielding is the important reason for frequent cable failures. In order to study the ablation mechanism of cable insulation shielding, a 110 k V cable electric-thermal cooperative test platform was designed, the change laws of test loop current under different voltages were tested, and the ablation damage degree of the insulation shielding under different ablation time were analyzed. The results show that the test loop current is significantly different under different test voltages. When the test voltage is lower than 50 V, the current grows slowly and is close to zero. When the test voltage is higher than 50 V, the current increases significantly and is more beneficial to observe the experimental phenomena. The surface ablation area and ablation depth of the insulation shielding increase with the increase of ablation time, and when the test voltage is 120 V and the continuous discharge time is 720 h, the ablation area and ablation depth of the insulation shielding layer reach 40 mm^2 and 1.8 mm, respectively. Finally, a partial discharge model of cable was established, it is found that the gap between the insulation shielding and aluminum sheath is the important reason for the ablation breakdown of insulation shielding, and some improvement measures were put forward to reduce the potential difference, which was helpful to prolong the service life and improve the reliability of the cable.

关 键 词：高压电缆 绝缘屏蔽 试验电压 气隙 局部放电 

分 类 号：TM247[一般工业技术—材料科学与工程]