Characteristics of the partial discharge pulse burst in transformer and switchgear oils

A study was carried out on the partial discharge pulse burst behavior in a mineral oil under ac conditions. The recurrence rate of pulse bursts was found to increase significantly with voltage above partial discharge inception. This was accompanied by an increase of both the number of discrete pulses and their amplitude within the pulse burst itself. These increases were reflected by a substantial rise in the apparent charge transfer per pulse burst as well as the overall charge transfer with increased applied voltage