Thermal characteristics of conduction cooled 600Â kJ HTS SMES system

A 600 kJ HTS SMES is developed and tested in Korea. The HTS SMES consists of 22 double pancake coils wound on each aluminum alloy bobbin. It is cooled by two GM cryocoolers down to around 6 K and current is charged through HTS current leads up to 275 A. Beside the heat penetration from room temperature structures, heat generation in the HTS coil is inevitable because of the joint resistances and the intrinsic property of the HTS tape such as index loss. Moreover, during the charging and discharging operation, AC loss of the HTS conductor and eddy current loss in the coil bobbin and metallic structures are generated. Therefore, the heat generation should be effectively removed by the cryocooler to ensure the stable operation of the coil. In the HTS SMES, aluminum alloy conduction plates outside the each coil are used as thermal paths to the cryocoolers. This paper describes the thermal characteristics of the HTS SMES for the charging and discharge operation.