抄録
The present paper reports the development of the refrigeration system that is applied to 70MW class superconducting generators (SCG). The main subject in developing the refrigeration system for verification tests on site was to develop technology for removing impurities in helium gas, which largely affects its reliability, and to further improve the reliability and efficiency of its main components as screw compressors, turbo expanders, and a low temperature adsorber. Thus this paper deals with its planning and performance testing as well as automatic control in different modes of operation (such as cool-down, steady-state and heat run) and also the reliability analysis. It was verified that the developed refrigeration system demonstrated a higher reliability of 14, 637 hours (MTBF), larger than 10, 000 hours. The total operation time at steady state has reached 9, 320 hours with no failures in the entire testing period.
