A Cryogenic System With High Capacity and Efficiency for HTS Cable

For mega-cities with growing electricity demands, the High-Tc superconducting (HTS) cables, owing to the distinct advantages of high electrical capacity and current density, become promising solutions to power grid reconstruction and expansion. The cryogenic system is expected to provide a vital low-temperature environment to ensure the steady operation of the superconductors. A cryogenic system based on the high-capacity Stirling-type pulse tube cryocooler (SPTC) developed in the authors' laboratory is now under coupling test with a short test line of the HTS cable. The aim is to meet stringent requirements such as high reliability, low maintenance, and high refrigeration efficiency which are desirable for the cables. The cooling capability of the SPTC in the HTS cable cryogenic system reaches 950 W at 72 K with a high relative Carnot efficiency (RCE) of about 14.5 % during the onsite coupling test with the HTS cable system. This paper will present the overall composition, operation mechanism, and integration technology of the cryogenic system for the HTS power cable in detail. The SPTC has been custom-developed for convenient and demountable connection with the cryogenic lines. The flow circulation, reliability design, and thermal analysis are also introduced. The performance characteristics and testing results will be presented and discussed as well.