In order to fully obtain GIL operation and maintenance situation in converter stations of Southern Power Grid

GIL application data are collected.The statistics show that the faults on the key components of the GIL includes:the abnormal noise of the GIL pipeline

the bursting of the three-pillar insulator and the excessive amount of partial discharge of the GIL unit.Aiming to investigate the causes of the above failures

this paper applies test verification combined with simulation calculation methods

which include disintegrated analysis

three-pillar insulator internal stress test verification

GIL axial shape variable simulation calculation

air gap electric field simulation calculation and interface air gap simulation test.The results of the simulation calculation and test show that the breakage of welding joint connected to the fixed particle catcher causes the abnormal noise in GIL pipeline.And the reason for the three-pillar insulator burst and excessive amount of the partial discharge of the GIL unit is that the three-pillar insulator has a small gap located at the interface between the low-potential metal insert and the epoxy resin.Finally

improvement measures are proposed to guide the subsequent project GIL production operation and maintenance based on the causes of GIL key component failures.