Electrical Conduction and Dielectric Breakdown in Liquid Dielectrics

Carrier injection and transport in various liquid dielectrics are influenced strongly by space charge effects. Intensive studies have been performed in time-resolved observations of the pre-breakdown and the breakdown phenomena, using ultra-short pulse techniques and high-speed optical measurement techniques utilizing a high-speed camera and lasers in combination with schlieren, Mach-Zehnder and shadowgraphic methods. Both electronic processes and bubble processes play roles depending on conditions: time range, pressure, electrode distance, etc. The influence of the molecular structure on the breakdown characteristics and the laser-induced breakdown are discussed.