The Study on the Overcurrent Pulse Testing of Bi-2223/Ag HTS Winding and HTS Transformer

This paper summarizes the experimental investigations on a small-scale air-core high-temperature superconducting (HTS) transformer operated in liquid nitrogen. The designed HTS transformer is being used as part of a current pulsed-power supply. First, the HTS winding was tested to experience a short overcurrent pulse. The results indicated that a 170-A critical current Bi-2223/Ag HTS winding can bear a short overcurrent pulse to at least 1 kA without being damaged electromechanically. The transformer consists of an air-core 48-turn primary winding, which is enclosed by a 6-turn secondary winding. The primary and secondary windings are one- and three-strand parallel conductors of Bi-2223 Ag-sheathed multifilamentary tapes, respectively. The experimental results show that the output current of the HTS transformer can reach up to 1154 A, which is several times than the critical current of the secondary HTS winding.