Characterization of leakage current of a post station insulator covered with ice with various surface conductivities

This research deals with the characterization of the time evolution of the leakage current (LC) during wet-grown ice accumulation on a porcelain station insulator. The results obtained demonstrated the influence of conductivity of applied water used for ice formation on the time evolution of the computed LC envelope. It was found that the influence of applied water conductivity is more significant after the icicles have completely bridged the insulator shed spacing than during their growth. During the formation of the ice bridge, erratic fluctuations in the LC envelope were observed which increased in intensity with increasing applied water conductivity. This was clearly identified by using the mean value of the empirical crossing spectrum (ECS) related to each LC envelope. In the same way, it was also demonstrated that the influence of applied water conductivity can be characterized by the cumulative energy of LC which can also be useful to identify the moment of shed spacing icicle bridging.