Abstract
In recent years, interest in the application of superconductivity to the electric power apparatuses has grown rapidly. In ac power apparatuses, loss induced by alternating current is a impeding problem which has to be reduced. A superconducting power cable is one of the promising ways for transmitting huge electric power efficiently in the future. We have proposed the new ac superconducting cable design with a similar electrical insulation structure to the conventional extruded cross-linked polyethylene cable (CV cable). The feature of this cable is to exploit the excellent electrical insulation capability of polymers at cryogenic temperature by separating helium coolant from the electrical insulation. The conductor of the superconducting cable consists of niobium clad over a copper flat wire and niobium tape, which are wound helically in the opposite direction each other on a copper pipe. In order to clarify the ac loss mechanism in this cable design, measurements and analysis of the ac loss of the superconductor have been carried out at the liquid helium temperature.
