Mechanical Properties of Polymers for Electrical Insulating Materials of Superconducting Power Cable

Abstract

A superconducting power cable is one of the promising ways for transmitting huge electric power efficiently in the future. We have proposed the new design of superconducting power cable with a similar electrical insulation structure to the conventional extruded cross-linked polyethylene cable (CV cable). The prominent feature of the design is to exploit excellent electrical properties of polymers in the cryogenic temperatures and to separate helium coolant from the electrical insulation. The cooling test of the cable showed that the most serious problem is a crack of polymer insulation due to a large difference in thermal contraction between the polymeric insulation and a conductor. Contractions, tensile properties and the influence of heat cycles on them were measured for some polymeric insulating materials. Furthermore, mechanical stress of the polymeric insulation of the cable at low temperature was calculated using the data of mechanical properties obtained. As a result, it is found that ethylene propylene rubber has superior mechanical properties in the cryogenic temperature region.