Power capacitors

The historical development of dielectric materials for high-voltage power capacitors is reviewed. Solid dielectrics have evolved from cellulose paper to synthetic polymers. Dielectric liquids have also undergone major changes over the years. The need to find alternatives to polychlorinated biphenyls (PCBs) in the mid-1970's led to advances in the fundamental understanding and synthesis of fluids with improved characteristics. Manufacturers continue to offer reliable power capacitors at low cost through their efforts to carefully assemble properly matched dielectric materials in near-particle-free environments. Current technologies are presented, along with a discussion of future directions.<>