Patent attributes
A superconducting cable has a further decreased diameter, and a DC transmission system incorporates the cable. The superconducting cable has a structure in which two cable cores, each having a superconducting conductor layer and an outer superconducting layer, are twisted together and housed in a heat-insulated pipe. Each cable core has a former, superconducting conductor layer, insulating layer, outer superconducting layer, and a protecting layer in this order from the center. In unipolar transmission, the superconducting conductor layers of both cores are used as the outward line and the outer superconducting layers of both cores as the return line. In bipolar transmission, the superconducting conductor layer of one core is used for the transmission for the positive pole, the superconducting conductor layer of the other core is used for the transmission for the negative pole, and the outer superconducting layers of both cores are used as the neutral-line layers.
