Abstract
Long-length high temperature superconducting (HIS) cable projects, over 1 km, are being designed that are cooled by flowing liquid nitrogen. The compact counter-flow cooling arrangement which has the supply and return stream in a single cryostat offers several advantages including smallest space requirement, least heat load, and reduced cost since a return cryostat is not required. One issue in long length HIS cable systems is the magnitude of the heat transfer radially through the cable. It is extremely difficult to instrument an HIS cable in service on the grid with the needed thermometry because of the issues associated with installing thermometers on high voltage components. A 5-meter long test system has been built that simulates a counter-flow cooled, HIS cable using a heated tube to simulate the cable. Measurements of the temperatures in the flow stream and on the tube wall can be made and compared to analysis. These data can be used to benchmark different HIS cable heat transfer and fluid flow analysis approaches.
