Interfacial breakdown in cable joints

Electrical breakdown at the interface of two dielectric surfaces is a complex phenomenon and is one of the major causes of failure for cable accessories. The dielectric strength of an interface increases with interfacial pressure and is substantially improved by the presence of electrical insulating greases. In order to better understand this phenomenon, interfacial breakdown experiments were carried out on interfaces found in cable joints. Measurements of breakdown voltage, interfacial pressure and grease conductivity were made to provide a comprehensive set of data for the investigation. This paper describes the experimental approach and discusses the preliminary results of the investigation on breakdown voltages found in new and field-aged cable splices