Study on electric insulation properties for development of conduction-cooled HTS SMES

Specially, this paper will present the results of high vacuum and cryogenic temperature breakdown and flashover discharge characteristics between cryocooler and magnet-coil. The breakdown and surface flashover discharge characteristics are studied at cryogenic temperature and vacuum. Also, some materials such as aluminum nitride (AlN), Al2O3 that have high thermal conduction are taken up and the flashover discharge characteristics are investigated. From the results, we confirmed that basic database on the discharge between cryocooler and magnet-coil was established for the electric insulation design.