Power outages due to contamination on outdoor insulators are a major concern for power transmission and distribution industry. Pollution deposition on outdoor insulators has been considered a major problem in the reliable transmission of power. Pollution constituents deposited on the insulator surface contains soluble and non-soluble contaminants. During rain, mist or cold fog the soluble contaminants dissolve in water to form a conductive layer on the insulator surface. This conductive layer leads to the flow of leakage current, Joule heating, dry band formation and under certain conditions may lead to flashovers and power outages.
This thesis presents a systematic study by discussing several aspects of the performance of silicone rubber outdoor insulators in humid and contaminated conditions. The effect of inert and active pollution, humidity, temperature, dry band location, dry band width and multiple dry bands on arc inception voltage, flashover voltage, leakage current, and surface resistance are investigated. All tests are carried out in the state of the art climate chamber of high voltage laboratory where humidity, temperature and fog rate can be effectively controlled. Numerical simulations are also performed in commercial simulation package Comsol Multiphysics to study electric field and potential distribution along standard polymeric insulators.
The output of this project will improve our knowledge concerning the flashover of contaminated polymeric insulators and will lead to better reliability of power system. These results could also be useful for asset managers and engineers to take crucial asset management decisions e.g. replacing or cleaning of insulators. These results can be used in developing condition assessment protocols and techniques for silicone rubber outdoor insulators.