合闸时陡波过程对中间接头击穿特性的影响

Research on Breakdown Characteristics of Cable Jointunder Steep Wave Process of Switching-on

电缆中间接头停电检修后,再次合闸投入运行时,屡次发生合闸瞬间或合闸后极短运行时间内出现的击穿现象,解剖发现击穿起始点位于导体屏蔽罩与电缆绝缘结合处内半导电屏蔽管上。为了查明中间接头击穿特性,利用试验、数学计算及电场仿真的方法,分析了中间接头内半导电屏蔽管的材料及结构对击穿性能的影响。研究结果表明,中间接头导体屏蔽罩与电缆绝缘结合处内半导电屏蔽管上电场随等效介电常数、伸出长度增加而增加。研究成果可为电缆中间接头绝缘结构设计、安装及应用提供参考。

The cable joint in operation after a period of time, the outage closing again when put into operation, the repeated occurrence of the breakdown phenomenon appears in the running time of the closing moments after closing or short, it is found that the breakdown in the starting point of anatomy and position of the conductor shield contact intermediate joint inner senti conductive shielding tube. In order to find out the breakdown characteristics of the intermediate joint, the influence of the material and structure of the senti conductive shield tube in the middle joint is analyzed by means of experiment, mathematical calculation and electric field simulation. The results show that the electric field at the senficonductor shield tube in the stress cone of the intermediate joint increases with the increase of the effective permittivity and the extending length, and decreases with the increase of the resistivity. By comparing the calculated results with the existing works, the material properties and the length of the extension applied to the steep wave during switching are obtained. The research results can provide reference for the design, installation and application reliability evaluation of cable intermediate joint insulation structure.