The electrical breakdown of insulating oil

Abstract

The past decade has seen great progress in our understanding of the mechanisms involved in the electrical breakdown of insulating liquids. This ‘academic’ approach has mostly used pure liquids in small quantities, and often the point-plane electrode configuration has been employed in the process of elucidation. To ‘practical engineers’ guided by standards and specifications set by the IEC (e.g. IEC 156) or other bodies little has changed over the past decade or two. Standard tests still give a standard deviation of the order of 20%, and water ingress, particle and fibre contamination and gas in solution are still the prime concern. How are these two view points to be reconciled?