Transient electrical and thermal responses of a 2-section BSCCO-2223 coil under overcurrent pulses

This paper presents experimental and numerical simulation results of 2-section coil subjected to overcurrent pulses in the temperature range 20-60 K. The experiment simulates a high-temperature superconducting (HTS) magnet for electric devices such as fault-current limiters, transformers, motors, and power lines under fault-mode overcurrent pulses. Each section of the test coil is layer-wound with Bi-2223/Ag composite tape, 3.5 mm wide and 0.23 mm thick, with the outer section wound directly over the inner section. A pulse current exceeds the critical current of each conductor and may drive each section normal. A constant current that follows the pulse current leaves each section in three possible conditions: completely superconducting, recovering, and quenching. Simulation agrees reasonably well with experiment.