一起GIS电缆终端局部放电缺陷闭环案例

A Closed-loop Case of Partial Discharge Defect in GIS Cable Terminal

电力电缆在城市电网中广泛应用,其安全稳定运行对可靠供电具有重要意义。通过特高频等带电检测手段,可在不停电条件下及时发现电缆故障,避免引起设备损坏与用户停电。介绍了一起通过特高频、高频电流法发现GIS电缆终端局部放电缺陷,通过幅值定位、时差定位等方式确定放电源位置,采用长时累计PRPD图谱诊断缺陷类型。停电解体后发现环氧树脂表面存在放电痕迹,终端表面存在黄色液滴与杂质,绝缘表面存在硅油干结形成的白斑与粉末。解体结果验证了带电检测手段的有效性,并为预防类似缺陷提供了参考建议。

The power cable is widely used in the city power grid, its safe and steady operation is very important for the reliable power supply. The online detection methods like ultra high frequency can discover the cable defects in time without the power-off, avoiding device damage and power outage. A case of partial discharge defect of GIS cable terminal is discovered by ultra high frequency and high frequency current methods.The amplitude location and time difference location methods are used to determine the position of discharge.The long-term accumulation PRPD is used for judge the discharge type. The disassembly result shows that there is discharge trace on the surface of epoxy resin, there are yellow liquid drop and impurities on the terminal, and there are white mark and powder after dry and hard of silicone oil. The disassembly result verifies the validity of online detection method and provides reference for preventing similar defects.