Design Features of ac Superconducting Cables

Alternating current superconducting cables which can be readily integrated into utility systems require both a superconductor with low characteristic ac losses and a high-performance cryogenic system to minimize the cost of heat pumping the thermal losses to the atmosphere. Moreover, the resulting cable systems must operate with the long-term reliability expected of utility systems. Recent publication have treated the measurement of the superconducting material properties and the conceptual electrical and cryogenic design for a superconducting cable. This paper will discuss a cable configuration and examine its electrical and cryogenic design features with principal emphasis placed upon the relationship of these features with present technological capabilities. Fabrication and installation feasibility and the expected levels of performance and reliability can be inferred from the practical operating cryogenic systems which are used as a guide for the selection and design of the cryogenic enclosure for the cable.