A model for insulation failure by partial discharges

Several attempts have been made to understand and anticipate the failure of insulation by partial discharges [1–4]. A large scatter is observed in relation to quantities characterising, partial discharges [PD]. Failure by PD, very often, does not take place where either the stress or the pulse magnitude or both are a maximum [1]. The total discharge magnitudes summed upto failure time [Qtp] are associated with specimen having large life and yet there seems to be some relationship between the characteristic quantities and failure. An attempt to look into this tantalysing situation is reported here.