Experimental Study on Quench Protection Method for HTS Coil That Uses Cu Tape Co-Wound With HTS Tape

The authors previously proposed a quench protection method for a high-temperature superconducting (HTS) coil that uses Cu tape co-wound with HTS tape (Cu-CW method). In this method, when a quench occurs in the HTS coil, part of the current in the HTS coil is quickly transferred to the co-wound Cu tape coil by shorting the Cu coil with a resistor due to the tight magnetic coupling of both coils, and the hot-spot temperature of the HTS coil is reduced due to the quick reduction of the HTS coil current. The previous work showed by a numerical simulation that the method is effective to improve the quench protection performance compared with a commonly used detect and dump method (D&D method). In this work, the effectiveness of the method was studied by an experiment using small-scale test coils wound with yttrium barium copper oxide (YBCO) coated tapes to experimentally simulate quench behaviours of HTS coils of significant scale.