一起35 kV内锥插拔式电缆终端击穿故障分析

Breakdown Failure Analysis of a 35 kV Inner Cone Plug in Cable Terminal

针对一起35 kV变电站主变高压侧内锥插拔式电缆终端击穿故障原因进行了分析。通过解体检查,发现故障原因为终端应力锥内主绝缘与承力环间有一明显不应存在的空隙,在长期运行电压作用下存在局部放电,导致电缆主绝缘及应力锥内壁绝缘劣化,并沿着应力锥内壁绝缘相对薄弱处延伸发展,在合闸投运操作过电压作用下造成击穿。

The reason for the breakdown of the inner cone plug in cable terminal on the high voltage side of the main transformer of a 35 kV substation is analyzed.Through disassembly inspection,it was found that the cause of the failure was that there was an obvious gap between the main insulation in the terminal stress cone and the bearing ring that should not exist,and partial discharge existed under the action of long term operating voltage,resulting in the deterioration of the main insulation of the cable and the insulation of the inner wall of the stress cone,and along the Due to the extension and development of the relatively weak insulation on the inner wall of the stress cone,breakdown occurs under the action of overvoltage during the closing operation.