Specifications and performance experiences of internally cooled small-scale SMES

SMES has a high potential for application in power utility, because of high plant efficiency, quick response, and power controllability. SMES is compo sed of a superconducting coil, vapor-cooled leads, and a power conditioning system. The electrical specifications for SMES are discussed on the basis of input and output power depending on size and application. As breakdown v oltage in helium gas is low, an internally cooled magnet system is preferab le to a pool boiling one. A model coil for a 100 kWh SMES, which is a typic al forced cooled magnet system, was developed in Japan and then successfull y tested. A glass-polyimide-glass tape insulation system was investigated i n view of electrical and mechanical-strength prior to fabrication. The brea kdown voltage measurement of a sample with an artificial crack showed suffi cient strength. The insulation critical fracture strength has a good agreem ent with the Mohr-Coulomb criterion. (C) 1998 Elsevier Science Ltd. All rig hts reserved.