Thermal stability of conduction-cooled HTS coils. Thermal stability analysis

In order to quantitatively evaluate the thermal stability of conduction-cooled HTS coils, thermal runaway currents of a conduction-cooled HTS single-pancake coil were measured at various temperatures and several cooling conditions, and numerically calculated using a calculus of finite differences. Calculated results were in good agreement with the experimental ones. A sensitivity analysis of thermal runaway currents for various physical values was also carried out. The thermal conductivity, specific heat and n-value of an Ag-sheathed Bi2223 wire do not significantly affect the thermal runaway currents of the coil. However, the critical current of an Ag-sheathed Bi2223 wire strongly affected the thermal runaway currents. Therefore, more precise critical current data should be prepared in the thermal stability analysis of conduction-cooled HTS coils. (author)