Analysis on surface characteristics of composite insulator materials after corona discharge

At present, composite insulator is widely used in the power system, and its safe operation is seriously affected by its aging condition. In order to research the aging feature of composite insulator material, this paper analyzes the surface characteristics of composite insulator after accelerated aging process via corona discharge, including surface hydrophobic, trap parameters and chemical components based on X-ray Photoelectron Spectroscopy (XPS), etc. It is revealed that, with the enhancement of corona discharge along with applied voltage and time etc, the hydrophobic property continuously decreases, trap parameters regularly changes, and surface chemical results show that content of hydrophobic micro groups decrease than before. The XPS analysis can be used to well explain the aging mechanism. With the aggravation of aging condition of composite insulator, its surface trap density gradually increases, which could be considered as a novel aging characterization parameter of composite insulator.