Partial discharge characteristics of liquid-impregnated laminate dielectric structures

Evolving power conditioning system requirements in many important technological areas will place severe demands upon repetitive pulse-power components. A principal pacing system component in high reliability, repetitive pulse-power technology is the energy storage capacitor. A joint program for the research and development of repetitively operated, pulse discharge energy storage capacitors has been initiated at the Los Alamos and Sandia National Laboratories. The purpose of this ongoing activity is to create the knowledge base necessary for the design and fabrication of materials-limited, multikilojoule capacitors that are continuously operable to 100 pps with lifetimes approaching 109 charge-discharge cycles at 99.99% reliability. Recently increasing availabilities of quality plastic films, especially polypropylene, and the discovery of the excellent properties of perfluorocarbon liquids for impregnation fluids (1) make spirally-wound, plastic film/liquid impregnated capacitors the leading candidate for high energy density, repetitively operated pulse discharge energy storage devices. The dominant lifetime-limiting mechanism in this type of high energy density capacitor is a direct result of partial discharge activity at the buried foil edges, where the electric field is maximum. An initial objective of this joint program is to characterize and understand the mechanisms of this partial discharge phenomenon.