摘要
Abstract
Aiming at the problem of surface discharge caused by the drift of foreign objects such as metal impuri-ties and sand particles inside gas insulated switchgear(GIS)equipment to the surface of basin-type insulators,this paper takes a 330 kV GIS fault as an example to deeply analyze the causes,development and evolution pro-cess and fault mechanism of such faults,and puts forward effective preventive measures.A comprehensive in-spection and verification of the faulty basin-type insulator and related equipment is carried out by using various technical means such as fault recording analysis,on-site opening inspection,factory disintegration inspection,gas component detection,X-ray imaging detection,power frequency partial discharge test and chemical compo-sition analysis of discharge residues.It is found that the root cause of the fault is that the foreign objects left on the corrugated gap of the bus or the butt surface of the gas chamber drift to the surface of the insulator under the action of vibration and electric field force,which first causes surface discharge,and then causes air gap dis-charge between the high-voltage conductor and the shell due to gas deterioration and metal melt splashing.At the same time,it is confirmed that there is no defect inside the faulty insulator,but the surface foreign objects and discharge products constitute two fault current paths,and induce the ferro-resonance resonance of the volt-age transformer,resulting in equipment damage.This paper proposes targeted preventive measures such as opti-mizing the structure of GIS gas chamber(e.g.reserving hand holes and setting up independent gas chambers),improving the design of voltage transformers(reducing the rated magnetic flux density),strengthening the con-trol of manufacturing and installation processes,and strengthening the operation and inspection management of in-service equipment.It has important reference value for improving the insulation performance,defect detec-tion ability and intrinsic safety level of basin-type insulators in GIS equipment.关键词
变电站/气体绝缘金属封闭开关设备/盆式绝缘子/表面异物/绝缘特性/沿面放电Key words
substation/gas insulated switchgear(GIS)/surface foreign object/basin-type insulator/insulation performance/surfance discharge分类
信息技术与安全科学
