Temporal and Frequency Analysis of the Leakage Current of a Station Post Insulator during Ice Accretion

This research is concerned with the analysis of leakage current, LC, of a porcelain standard station insulator during a glaze ice accretion. The results obtained show that the leakage current during ice accumulation goes through two distinct periods characterized by specific LC waveforms and frequency harmonics. Laboratory tests demonstrated that the duration of the first period is directly dependent on the icing rate. Hence, measuring the duration of the first period is equivalent to measuring the icing rate. However, this requires the determination of either the transition between the two periods or the detection of the onset of the ice accumulation. The results show that icing rate measurement can be achieved by using results of leakage current analysis, like the time evolution of the third and fifth harmonic, as well as the phase angle difference between leakage current and applied voltage. This analysis makes it possible to characterize the severity of an ice accumulation on a porcelain station insulator.