Cryogenic refrigeration system for HTS cables

The cost and reliability of cryogenic refrigeration is key to successful commercialization of High Temperature Superconducting (HTS) cables. This paper describes the design and initial test results of the Cryogenic Refrigeration System (CRS) that will be used in the 350 m HTS cable demonstration at Albany NY. The 34.5 kV/800 A HTS cable will be installed in the distribution power grid of Niagara Mohawk. The CRS will provide a nominal 6 kW closed cycle refrigeration at 77 K, and will have a lower operating temperature of 66 K. The CRS has a core heat exchanger that will accept any mechanical refrigeration unit (cryocooler), and is designed to provide unlimited back-up refrigeration capability. Following the completion of the testing reported in this paper, the CRS will be installed and commissioned at the Albany site beginning late 2004. Once onsite, the CRS will be continuously monitored throughout the HTS cable demonstration using BOC´s remote operations infrastructure.