In order to reveal the deterioration characteristics of the high temperature heating line rod composite insulators

this paper has carried out a study on a 220 kV fault insulator of the Jiangmen Power Supply Bureau of Guangdong power grid.The appearance of the insulators was observed and the infrared and ultraviolet detection was carried out under the charged state.Then the anatomical observation was carried out.The material characteristics of the core rod deterioration and normal location were compared with modern material testing method（SEM and XPS）.The electrical parameters of the short rod of the deteriorating part and the normal mandrel were compared with the broadband dielectric spectrometer.The experimental and anatomical results show that the surface of the insulator is perforated

the pressure temperature rises seriously

and the external discharge is weak.The surface degradation of the mandrel at the internal interface has been extended from the high pressure end to the middle.The material analysis shows that the core rod at the interface is seriously damaged by electric discharge.The epoxy resin is cracked

and the glass fiber is cracked and eroded.There are deterioration processes such as oxidative decomposition and acid liquid erosion.In addition

the dielectric constant

dielectric loss tangent and electrical conductivity of the core rod increased significantly

resulting in further distortion of the electric field and enhanced partial discharge.The research shows that the core rod of the high temperature heating line composite insulator is deteriorated seriously

and the partial discharge and other deterioration processes are more severe

and the risk of fracture is great.