Effects of pollution on potential, electric field and heat distributions in high voltage insulators

High voltage insulators are exposed to overvoltage. In this process, there should be no disruption in their performance of insulation and support duties. Therefore, electrical properties must be known. The aim of this thesis is to examine the voltage, electric field and temperature changes caused by the pollution of the insulators due to their environmental conditions. It is among the important hypothesis of this thesis that different conductivity levels of dirt can make significant changes on the electric field, potential distribution and heating. In this study, the insulator is modeled in two-dimensional axial symmetric and three-dimensional with the finite element approach together with the electrical properties of the materials in its structure in COMSOL Multiphysics program. The air around the insulator has been drawn in a smaller size, but by adding an infinite domain provided by the program to its outer periphery, the effect of infinite elements has been fitted to this dimension and data have been obtained. The increase in conductivity made the potential distribution linear. The equipotential curves, which are seen intensely around the pin in the clean condition, are dispersed with the increase of dirt conductivity. In the electric field studies, the highest electric field strength was generally seen at the pin-cement-air and cap-insulator-air intersection. It was observed that the temperature level increased with the increase in conductivity and applied voltage.