Breakdown of a thin dielectric liquid layer and interfacial phenomena

The author describes measurements of electrical breakdown on thin liquid dielectric (capacitor impregnant) layers for different interfacial situations. The dielectric strength depends on various factors such as electrode area, gap spacing, the nature of the interface in contact with the liquid, and temperature. The breakdown phenomena are shown to be either connected to high-field conduction-boiling or electrohydrodynamic cavitations leading to the generation of a vapor bubble in the prebreakdown regime-or related to the presence of particles and/or local field enhancements