The effect of voltage frequency on partial discharge activity

The knowledge of partial discharge (PD) as a physical phenomenon has made considerable progress in the last decade(s). These efforts have led to a validated statistical-mathematical model able to simulate the PD behavior in dielectric bounded spheroidal cavities. Recent studies demonstrated that an approach based on simulations can give both qualitative information on the PD process and a good estimation of the main PD quantities (PD magnitude, PD inception/extinction voltage, PD pattern). This theoretical operating procedure was until now restricted to discharges ignited at the power stress frequency of 50 (60) Hz. In this paper the authors describe the use of a procedure to simulate partial discharges in dielectric bounded spheroidal cavities at frequencies in the range of 0.1 Hz....1000 Hz. Information on the effect of voltage frequency on the PD process has been derived from the simulation results. The results were validated by measurements at a range of test frequencies on test specimens containing spherical cavities.