一起110 kV GIS电缆终端局部放电案例分析

A Case Analysis of Partial Discharge at 110 kV Gas Insulated Switch-Gear Cable Terminal

摘要: GIS设备由于其结构为全封闭的特性，带电运行中无法用传统的检测方法对其内部绝缘状态进行监测，只能通过超声波、特高频等带电检测手段对其进行诊断。本文介绍了一起通过带电检测技术发现济南某变电站110 kV GIS电缆终端存在悬浮类放电的缺陷案例。首先，通过巡检发现某电缆终端存在异常放电信号，判断该气室存在悬浮类放电；随后利用特高频时差法和超声波法进行定位分析确定了放电气室；最终通过解体检查发现该气室A相电缆终端导电端子压接不合格，电缆应力锥均压环存在明显的松动在高压环境下产生悬浮类放电信号。该起GIS电缆终端局部放电案例为今后类似缺陷的检测和处理提供了经验与参考。

Abstract: Due to the characteristics of its fully enclosed mechanism, GIS equipment can not use traditional detection methods to monitor its internal insulation status during operation, and can only diagnose internal defects through live detection methods such as ultrasound and UHF. This article introduces a case of a suspended discharge defect found in a 110 kV GIS cable terminal of a substation in Jinan through live detection technology. First, the abnormal discharge signal is found in a certain cable terminal through inspection, and it is judged that the air chamber has suspension discharge; Then the UHF time difference method and ultrasonic method are used to locate and analyze the discharge air chamber; Finally the air chamber is found through disassembly inspection. The crimping of the conductive terminals of the A-phase cable terminal is unqualified, and the cable stress cone equal-izing ring is obviously loosened to produce a floating discharge signal in a high-voltage environment. This GIS cable terminal partial discharge case provides experience and reference for the detection and treatment of similar defects in the future.