A fuzzy logic based approach to evaluate the surface conditions of ceramic outdoor insulators

This paper aims to establish criteria for the automatic classification of surface conditions of outdoor insulator based on the leakage current (LC) analysis and fuzzy logic approach. The study is done in an artificial fog chamber and the LC is characterized for different stages; e.g. dry, wetted and presence of early discharge activities. Time-frequency and spectral analysis are adopted to calculate the evolution of LC characteristics that will be used as a classification criteria. The obtained results show that phase angle analysis and Std-MRA present an effective indicator for the surface conditions. A system based on the fuzzy approach is presented to classify the early signs of dry band arcing as an indication for insulation washing.