Critical Assessment of the Electrical Breakdown Process in Dielectric Fluids

The phenomenon of electrical breakdown in insulating liquids has been investigated extensively for decades by many researchers all over the world. Several theories have been advanced, based on more or less limited experimental evidence. Also attempts were made to apply to liquids concepts derived for the breakdown of solids and gases. In the last decade the advent of very high speed electrooptical tools has made it possible to elucidate this process in much more detail than was previously possible. It has become possible to show that at least three stages are involved in the development of the ultimate breakdown. In this paper a brief review of the early work will be presented. Then the more recent experimental results are summarized, and finally a comprehensive model of the breakdown process is proposed.