Electric field distribution is one of the important factors which impact the aging of composite insulators. The electric field of composite insulators was simulated by ANSYS software, and the shed samples in different parts of the composite insulator were analyzed by Fourier transform infrared spectroscopy (FTIR). The characteristic peaks of functional groups in the main chain and side chain of composite insulator material molecular formula were compared. The smaller the characteristic peak area is, the less the corresponding functional group is, that means the facture condition of main chain or side chain is more serious. In this way, the characteristic peaks of samples in different electric field distribution were compared, and the influence of electric field distribution to the aging effect of the composite insulators is gained. The results show that electric field strength is the strongest in the composite insulator high-voltage side, followed by lowv oltage side, and the electric field in the middle of the composite insulator is the lowest. Accordingly, the aging degree in the composite insulator high-voltage side is the most serious, followed by low-voltage side, and the aging degree is weakest in the middle part.

Keywords: Aging, Composite insulators, Electric field, Fourier transform infrared spectroscopy (FTIR)