The behavior of physical and stochastic parameters from partial discharges in spherical voids

An investigation of the time behavior of physical and stochastic quantities associated with partial discharges occurring in gas cavities present in solid electrical insulation is dealt with in the paper. The physical model proposed by Niemeyer is implemented and applied to measurements of partial discharges occurring at different levels of electric field, following the modification of the partial discharge pattern with aging time. Even if the aging time is not long enough, at the time of writing this paper, to achieve significantly different partial discharge patterns, the time evolution of stochastic parameters, as average discharge amplitude, average discharge number and scale parameter of charge-amplitude Weibull distribution, is well simulated and explained by the model resorting, in particular, to void-surface conductivity variations. Likewise, partial discharge patterns are well simulated, both qualitatively and quantitatively