Analysis of a Liquid Nitrogen-Cooled Tri-Axial High-Temperature Superconducting Cable System

Abstract

This tri‐axial high‐temperature superconducting (HTS) cable design uses three concentric superconducting layers for the phase conductors, separated by a cold dielectric material. The design offers an efficient HTS cable configuration by reducing the amount of superconductor needed and places all three phases in a single cryostat. The tri‐axial cable cooling circuit analyzed includes heat loads at the ends for the cable terminations and cable heat loads due to ac, dielectric, and thermal losses. The HTS cable critical current and ac loss are functions of the local temperature that must be determined by the analysis. The radial heat transfer also has an influence on these parameters due to the relatively low thermal conductivity of the dielectric material separating the HTS phases. The study investigates whether the tri‐axial cable must be cooled both inside the former and outside of the cable. In this study, the range of operating parameters for a tri‐axial HTS cable system and refrigeration requirements are determined based on expected HTS tape performance.