Understanding the water droplet initiated discharges with epoxy SiC nanocomposites under AC voltage

The Surface damage caused due to water droplet initiated discharges was found to be more in case of epoxy resin compared to epoxy SiC nanocomposites. The erosion area was having a direct correlation with the no of droplets sitting over the sample surface irrespective of nature of sample. The discharges were always started from HV electrode and termi­nated near the ground electrode irrespective of the number of water droplets. The corona inception voltage was found to be affected by volume as well as conductivity of water droplet. The frequency component contents of the UHF signal captured in sequence mode during inception level to arc extinction level were analyzed through Ternary plot analysis. Bascically four modes of oscillations of water droplet were observed during the discharges due to variation in the tangential electric field. The nature of the resistive current during the arc initiation was observed to be same irrespective of the number of water droplets but the no of discharge pulses were having a direct relationship with the number of droplets.