Progress in the Development of Gas-Impregnated Lapped Plastic Film Insulation

A flexible superconducting power transmission cable in under development. The electrical insulation consists of lapped polymeric film tapes impregnated with supercritical helium. Ways of satisfying the many constraints on the material are described. Although the cable is intended for low-temperature operation good electrical and mechanical characteristics are needed at room-temperature. Results are given for both small- sample tests and a model cable fabricated commercially. The results are compared with those obtained by other workers and the design of the next test cable is given. Work supported by the U. S. Energy Research and Development Administration, the Electric Power Research Institute and the National Science Foundation.