Energy quantification of corona discharges on polymer insulators

Surface hydrophobicity is one of the factors that contribute to the superior performance of polymer insulators when compared to porcelain. However, corona discharges that can be generated locally due to high electric field can destroy hydrophobicity and also contribute to the degradation of the insulator. This paper presents a method to quantify the energy associated with corona discharges on the surface of the insulator under a variety of atmospheric conditions. Image processing techniques are used to measure the brightness of the discharge in terms of pixel illumination levels. A correlation is drawn between the image obtained with a corona detection camera at the ground level and the energy associated, as measured by traditional partial discharge (PD) detection methods. Simulation results are reported, together with discussion of various problems.