Overturning Force Simulation on Normal-State Transition of Toroidal HTS-SMES Taking Into Account an Electromagnetic and Thermal Condition

Recently, many investigations about toroidal high-temperature superconducting magnetic energy storage systems have been reported. Some papers reported that there was a possibility that the chain of normal-state transitions occurred on the toroidal HTS-SMES magnet by normal-state-transition simulation. Hence, it should also be investigated that the behavior of unbalanced electromagnetic force during the sequential normal-state transition of the superconducting coil elements. In this paper, we have developed a simulation code to investigate the behavior of the overturning electromagnetic force on the toroidal HTS-SMES system during the normal-state transition. The magnetic field and the circuit analysis were coupled and solved in the previously developed simulation code. Additionally, in order to investigate the normal-state transition more accurately, we also take the thermal analysis into account. Carrying out the newly developed numerical simulation, we investigate the time transition of the transport current, the overturning force, and the magnetic field applied to the superconducting coil elements for a few toroidal HTS-SMESs.