Development of Helium Refrigeration Systems for 70 MW Class Superconducting Generators

Publisher Summary Super-GM has been established to develop technology for superconducting generation (SCG) equipment and materials as a national project. It has been developing two types of high reliable refrigeration system for the SCG; a conventional refrigeration system using oil injected screw compressors and an advanced refrigeration system using oil flee compressors. The main subjects in developing its refrigeration system for verification tests on site of the SCGs are to develop technology for removing impurities in helium gas which largely affects its reliability and to further improve the reliability and efficiency of its components. Through factory testing a developed refrigeration system is so far confirmed to meet its requirements as a liquefaction capacity, a precooling capacity, and an automatic control to different modes of operation. This chapter represents a planning of the refrigeration system for the SCGs, the results of performance testing at the factory and a discussion on reliability is also addressed in the chapter.