Contamination Level Assessment in Porcelain Disc Insulator using Detrended Fluctuation Analysis

Power system networks mainly use porcelain disc insulators for insulating live conductor from supporting structure. Insulators, used in power system network are generally employed for open-environment applications. Outdoor porcelain insulator discs get easily contaminated due to different types of pollutants such as salt, kaolin, heavy rain, fog, humidity. Further, these pollutants provide path for leakage current to flow along the surface of the insulator. This leakage current magnitude increases with increase in contamination and humidity. Therefore, identification of contamination level for porcelain insulator disc is necessary for uninterrupted and smooth power system operation. Hence, in the present work, a methodology is proposed to estimate the levels of contaminations using leakage current measured from an 11kV porcelain disc insulator (simulating different contamination levels). Detrended fluctuation analysis (DFA) has been applied on the measured leakage current profiles to provide meaningful information about contamination deposited on insulator surface.