Influence of hydrostatic pressure on the characteristics of discharges propagating on solid/liquid insulating interfaces under AC and DC voltages

This paper is aimed at the influence of the hydrostatic pressure on the discharge propagating at the liquid/solid insulating interfaces under AC and DC voltages using a point-plane electrode arrangement. It is shown that different shapes of creepage discharges and associated currents can be initiated for the same experimental conditions indicating the existence of different propagation modes of discharges. On the other hand, the final length and the number of creepage discharge branches, the corresponding currents and the light emitted are reduced when a hydrostatic pressure is applied; this indicates the implication of gaseous processes in the creepage discharge phenomena. The final length of discharges increases quasi-linearly with the voltage, whatever the type (DC or AC) and polarity of the voltage, and decreases quasi-linearly when the pressure increases.