Detecting partial discharge of polluted insulators based on ultraviolet imaging

Insulator is one of the most commonly used devices in transmission lines, so that the reliability of insulators is of great importance to the stable and safe operation of the electric grid. This paper analyzed the filthy discharge of polluted insulators based on ultraviolet (UV) imaging detection technology. By establishing an equivalent circuit model of polluted insulators, this paper analyzed and processed the causes and influencing factors of filthy discharge. Insulators were polluted artificially and discharged in the artificial climate chamber. The images and videos of this process were recorded and processed, based on which a characteristic of these images has been extracted and defined as “facula area percentage”. By analyzing and comparing the images´ characteristics of discharges under different pollution level and different relative humidity, this paper acquired the patterns of how insulator discharges are influenced by pollution and humidity. By analyzing the influencing factors, such as gains, shot angles and distances, to the characteristics of those UV images, this paper also worked out the conversion formula under different gains, shot angles and distances, and proposed a standard for UV imaging.