Design Comparisons of Concentric Three-Phase HTS Cables

Four different cooling options for three-phase concentric medium-voltage HTS cables have been investigated. These four cooling options differ in the feed-in and return of the liquid nitrogen and in the utilization or nonutilization of an annular gap cooling and are so determining the whole cable design. Simulations of pressure drops and temperature profiles have been carried out to evaluate the construction limits and the efficiency of each design. The simulation results provide the maximum transmission lengths and minimal cable diameters for a given transmission power and a defined cable operation range. The results indicate that a design without annular gap cooling can lead to a compact cable design and a high transmission length at the same time.