Research And Engineering Application Of Insulating Properties Of GIL Three-pillar Insulators

Since the "Liangdu" DC project was put into operation,GIL equipment failures in Puer Converter Station and Niuzhai Converter Station frequently occurred.Problems such as abnormal noise defects of GIL pipelines,three-post insulators burst failure,and abnormal GIL unit partial discharge had occurred successively.In order to find out the reason that caused GIL equipment,which were at Puer Converter Station and Niuzhai Converter Station,came up fault,and better guide the production of GIL equipment at Xinsong Station in northwestern Yunnan.Comprehensively sorted out the situation of the operation and maintenance of GIL equipment in the "Liangdu" DC project,and carried out the typical fault/defect analysis and insulation characteristics research of GIL equipment in the DC project.This article focuses on the research of the insulation characteristics of GIL.First,it introduces the typical structure of GIL equipment,analyzes the typical failures of GIL equipment in operation by UHV companies,finds out the cause of the failure,and proposes anti-accident measures and process improvement measures.Then,the simulation and experimental research on the internal and external insulation characteristics of GIL three-post insulators were carried out,which confirmed the causes of insulator defects,and proposed a product optimization design plan to reduce the triggering conditions of the surface discharge of GIL three-post insulators.Using the research results,we optimized the welding process standard requirements,and completed the repair work of all GIL unit solder joints in Puer Converter Station and Niuzhai Converter Station.And finally solved GIL abnormal noise,burst and abnormal partial discharge problems.During the delivery process of the GIL equipment of the Xinsong converter station of the Northwest Yunnan DC project,a large number of three-post insulators and external flash three-post insulators,which were with air hole on the surface,were first removed,and the three-post insulators production mold,process control measures and fixed three pillar assembly process were optimized.Then redesigned the fixed three-post connecting plate and sliding base.Finally,the improved three-post insulators was tested,and all passed the verification of mechanical test,transportation test,and electrical test.The 2400 m GIL equipment handover test of the Xinsong Converter Station of the Northwest Yunnan DC Project passed one-time,and it has been running well since it was put into operation.The research results have shown the good economic and social benefits.