一起局部放电特高频在线监测系统发现的GIS缺陷分析

Analysis on One GIS Defect Found by Partial Discharge UHF On-line Monitoring System

基于一起特高频(ultra high frequency,UHF)在线监测系统发现的气体绝缘开关(gas insulated switchgear,GIS)缺陷分析了缺陷发展情况,并采用便携式局部放电检测设备进行定位,对故障气室进行了解体处理,积累了GIS局部放电在线监测运行经验。在线监测结果表明,本次缺陷为突发性悬浮放电,缺陷发生后持续存在,幅值较大,且定位发现缺陷位置靠近断路器气室。为预防短路事故,进行了停电处理。解体发现断路器气室靠近电流互感器侧的盆式绝缘子触座底部存在明显的放电痕迹,导体表面有明显的环形伤痕,触座内部存在大量金属粉尘。分析认为该导体结构设计不合理是引起局部放电的主要原因。运行经验表明,通过安装GIS局部放电UHF在线监测系统,可以发现GIS隐患,有效保证电力系统安全稳定运行。

Based on one gas insulated switchgear defect found by UHF on-line monitoring system, this paper analyzes its de- veloping status, uses portable partial discharge detecting device to carry out positioning and disintegrate management for the fault chamber which gathers experiences for GIS partial discharge on-line monitoring operation. The on-line monitoring re- sult shows that this defect is a kind of sudden suspended discharge which exists continuously after the defect occurs with lar- ger amplitude and through positioning it finds that the position of defect is close to the breaker chamber. For preventing short-circuit accident, it processes power cut. The disintegrate management finds there is obvious discharge trace at the bot- tom of contact base of basin type insulator which is close to current transformer side in breaker chamber and there is also some obvious ring scar on the surface of conductor, meanwhile there is abundant metal dust inside the contact base. It analy- zes and considers that the main reason for partial discharge is unreasonable design of the structure of conductor. Operation experience shows that by installing GIS partial discharge UHF on-line monitoring system, it is able to find GIS hidden danger and effectively ensure safe and stable operation of the power system.