Aiming at the problem of aging of composite insulator

a composite insulator with seven years running history at power grid is analyzed.Its electric field is computed through finite elements method

and the electric field intensities at different umbrellas are compared.The microstructures of silastic aged under electric and ultraviolet effects are also compared by analyzing the SEM photos of different silastic sections of the umbrellas.The comparison between the microstructures of top and bottom surfaces of umbrella demonstrates the rules of electric aging and electric erosion.The possibility of surface contamination moving inside silastic is studied via energy spectrum analysis.The results will be helpful for research of composite insulator aging and optimization design of anti-aging.