This article introduces the cryogenic power cable, especially its thermal and electrical insulations. These are important matters on the reliability of cryogenic cables. Thermal insulating methods for cables are similar to general cryogenic vesseles. However the length of the cable makes some troubles in evacuation, formation, etc. The applications of thermal insulating methods are discussed with the examples of several plants. Electrical insulating materials at low temperature have been researched in these few years. Solid materials have no reliability because of thermal cracks. Polyethylene paper laminated insulation impregnated with liquid nitrogen has good performance for liquid nitrogen cooled cable. For the superconductive cable, supercritical helium impregnated tape-type insulator seems promissing as electrical insulating methods.
