某220kV变电站110kV GIS母线异常分析

Analysis on Abnormal Busbar of 110kV GIS at 220kV Substation

文中针对某220 kV变电站110 kV GIS(气体绝缘开关设备)母线异常状况展开深入研究,通过外观检测、超声波局部放电检测、X射线检测和局放在线监测等技术手段,综合分析诊断该母线异常是由Ⅰ母1号伸缩节右侧母线筒内B相支撑绝缘子存在毫米级间隙导致悬浮电位放电而产生。结合解体分析和3D立体扫描检测技术,对其产生原因进行分析。研究发现本次异常的B相支撑绝缘子金属嵌件制造尺寸高于正常相,导致安装屏蔽罩后金属嵌件高于屏蔽罩外表面,从而造成B相屏蔽罩未能与母线有效压紧。随着母线的相对运动或振动存在失去等电位接触可能,进而导致屏蔽罩产生悬浮电位,此间隙可能随着负荷及温度变化而变化,从而形成阵发性悬浮放电信号。文中首次通过3D立体扫描技术实现对GIS母线异常的成功诊断,为电网设备故障检测、诊断、分析和治理开辟了新途径。

In this paper,a deep research on abnormal condition of busbar of 110 k V GIS(gas insulated switchgear)at 220 kV substation is performed.Through such technical means as appearance inspection,ultrasonic partial discharge detection,X-ray inspection and partial discharge on-line detection and comprehensive analysis,it is determined that the abnormality of the busbar is caused by the millimeter clearance of phase B support insulator of busbar enclosure which is in the right side of No.1 expansion joint of I busbar,causing potential discharge. Combined with disintegration analysis and 3D stereoscopic scanning detection technology,the reasons for its occurrence are analyzed.It is found by the research that the manufacturing size of the metal inserts of abnormal support insulator in phase B is higher than that of the normal phase,which causes the metal insert to be higher than the outer surface of the shield after installation of the the shield,resulting in the shield of phase B not compress effectively with busbar.With the relative movement or vibration of the busbar,it is possible to lose the isopotential contact,which in turn causes the shield to generate a floating potential.This clearance may change with the variation of load and temperature,thereby forming a burst of suspended discharge signals.In this paper,the successful diagnosis of GIS faults is realized by3D stereoscopic scanning technology for the first time,which opens up a new way for the detection,diagnosis,analysis and management of power grid equipment faults.