Research on defect type diagnosis of composite insulator based on infrared detection technology

Abstract

Composite insulator is widely used in Hainan area of China because of its lightweight, small volume, good anti pollution flashover performance and many other advantages. Aiming at the problem of how to correctly judge the aging state of composite insulators under live conditions in Hainan’s high humidity environment, this paper analyzes the main causes of composite insulator heating and the heating position and temperature rise of composite insulator under different defect types by building equivalent circuit, and puts forward several criteria for distinguishing the defect types of composite insulator by infrared detection technology; taking the abnormal temperature rise of 220kV returned composite insulator in Hainan as an example, the defect type of the composite insulator is analyzed by infrared detection technology, and the correctness of the infrared results is verified by the appearance inspection and anatomical analysis of the test object. The results show that the defect that the temperature rise is between 1-5°C and only appears among the fittings and the first umbrella is caused by the aging, moisture absorption or surface pollution of the umbrella cover; the defect that the temperature rise is above 5°C and the range extends from the high-voltage end sheath to several umbrella skirts is caused by the internal deterioration of the insulator. In conclusion, the conclusion provides a guarantee for the safe operation of power grid and has important reference value for the study of on-line monitoring of composite insulators.