Study On Multiphysics Distrubution And Insulation Aging Characteristics Of Composite Insulation Bushing&CT

In recent years,power equipment using composite insulation sleeves has gradually been widely used in power grids.The external insulation of oil-immersed bushings and current transformers is usually a porcelain sleeves,but the failure of the porcelain sleeves explosion occurs,which makes the equipment using the porcelain insulation a greater safety hazard.The composite insulation sleeves made of silicone rubber and FRP has good elasticity,can effectively release the pressure when the insulation failure occurs inside the device.At the same time,composite insulator has been widely used on insulator strings and substation equipment,with the technical feasibility of replacing porcelain insulator.Therefore,to study the multi-physics field distribution of composite insulation oil-immersed bushings and current transformers and the aging of composite insulator is to understand the operating state and insulation aging process of composite insulation oil-immersed bushings and current transformers.And it is the foundation to enhance the reliability of composite insulation sleeves and current transformers.In this paper,the composite insulating oil-immersed bushing and current transformer are taken as the objects.Based on the actual size structure,the finite element simulation analysis model is established.Through the finite element simulation,the electric field,magnetic field and temperature field distribution of the bushing and CT during stable operation were studied.The induced current and losses generated in the conductors of the bushing and CT during operation were determined.The size and position of the maximum electric field inside and on the surface of the bushing and CT were determined.The temperature of each part of the bushing and CT were determined.Secondly,in view of the serious problem of the aging of composite insulation materials,the composite insulation materials used in bushings and current transformers were taken as the research objects.Through the thermal oxygen accelerated aging experiments in the laboratory,the performance changes of high-temperature vulcanized silicone rubber after thermal aging were studied,with emphasis on the hydrophobicity and pollution flashover characteristics of the surface of the silicone rubber.Fourier transform infrared spectrometer（FTIR）was used to comparatively analyze common fillers in silicone rubber,such as ATH,Si O₂ and PDMS and ordinary silicone rubber.Combining FTIR to explain and analyze the performance of silicone rubber after thermal aging.Finally,taking the composite insulation bushings and CT prototypes as the research objects,an ultraviolet aging experiment platform for the prototype was built.Through the ultraviolet aging of the prototypes’HTV silicone rubber umbrella,the performances and characteristics of prototype HTV silicone rubber umbrella was studied,with the emphasis on the surface hydrophobicity of the silicone rubber umbrella and insulation properties of the protypes.In this paper,the composite insulation bushing and the current transformer are taken as objects,the simulation of its multi-physics distribution characteristics and the insulation aging experiment of the composite insulation sleeves are carried out,which provides a theoretical basis for the manufacture and reliable operation of UHV composite insulation equipment.