两起110kV穿墙套管介损超标的原因分析

Reason Analysis for Two Cases of Dielectric Loss Over-standard of 110kV Wall Bushings

高压穿墙套管是一种比较常见的电气设备,运行中的高压套管一旦绝缘损伤,则可能发生闪络、放电,严重时可能造成绝缘击穿,给电力系统的安全运行带来巨大的损失。电容式套管介损测量是判断套管绝缘状况的一项重要手段,通过对两起110 kV干式穿墙套管例行试验数据的异常情况进行诊断性试验(主要进行主绝缘电阻、末屏绝缘电阻、主绝缘介损、末屏对地介损测量及数据对比分析)及其套管的解体检查,找出缺陷原因,提出预防穿墙套管发生故障的防范措施,从而提高系统的安全运行。

High voltage wall bushing is a kind of common electric equipment which is probably to flashover and discharge once there is insulation deterioration in its operation, even in serious case, it is likely to cause insulation breakdown due to the above faults, which may bring great loss to security of the power system. Measurement on dielectric loss of capacitor bushing is one of important method for judging insulation state of the bushing, this paper tries to find out reasons for defects by diagnostic experiments on ab- normalities of routine experimental data of two cases of 110 kV dry wall bushings including measurement on the major insulation re- sistance, end shield insulation resistance, the major insulation dielectric loss and end shield grounding dielectric loss as well as data comparison analysis. It also conducts disassembling check on the defected bushings and proposes precautionary measures for preven- ting failures in wall bushings so as to improve security of the power system.