Analysis of Water droplet initiated discharges on silicone rubber insulating material adopting Hilbert huang transform

Water droplet residing on surface of roughened silicone rubber generates corona activity at much lower voltage compared with the virgin specimen. An increase in conductivity of water droplet, under AC voltage, shows a reduction in corona inception. Further, a combination of time series analysis and fractal feature extraction techniques are used to classify the different phases that occurs on application of AC voltage to the water droplet sitting on silicone rubber specimen, in the electrode gap. The fractal dimension and the lacunarity were calculated using the 2D Hilbert energy spectrum obtained with leakage current measured during water droplet initiated discharges, shows inverse relationship.