Effect of Direct Voltage Ripples on Partial Discharge Activity

This paper examines the effect of direct voltage ripples on partial discharge intensity. Partial discharges in a solid cellulose dielectric were experimentally studied at alternating and direct voltage of both polarities with different ripple amplitudes. It is shown that when exposed to direct voltage, the intensity of partial discharges depends on the ripple factor of the direct voltage. The ripple factors of direct voltage at which the intensity of the partial discharges is less than when exposed to alternating voltage are experimentally established. The effect of direct voltage ripples on the value of the apparent charge of partial discharges, their number, and the distribution of discharges in the time domain are experimentally established.