Optical and electrical investigations on creeping discharges over solid/liquid interfaces under impulse voltage

This paper deals with the experimental characterization of discharges propagating on solid/liquid interfaces under impulse voltages using a point-plane electrode arrangement. It's shown that the nature and the thickness of the solid insulating significantly influence the characteristics of creepage discharge and especially the density of branches. This later decreases when the thickness of the solid insulator increases. This indicates the important role of the capacitive effect in the propagation mechanism. For a given thickness, the final length of these discharges increases quasi-linearly with the voltage. The current waveform of creepage discharges depends on the polarity of the voltage.