Design and Test Results of a Fault Current Limiter Coil Wound With Stacked YBCO Tapes

This paper describes the design and test results of a 6.6 kV-class superconducting fault current limiter (FCL) coil wound with YBCO tapes. YBCO tapes, with stainless-steel lamination, were prepared for an experimental FCL coil. The main feature of this FCL coil is winding of multiple YBCO tapes in parallel in order to increase the rated current. To obtain a rated current up to several hundred amps, four tapes, electrically insulated, were wound in parallel to form a non-inductive coil. The coil specifications, such as winding pitch, number of turns, and transpositions, were carefully designed by numerical simulation to equalize the current distribution in each tape. The fault current limiting performance of the FCL coil was evaluated through over-current tests using a capacitor bank. The FCL coil successfully suppressed a fault current of 10.4 kA to below 2.1 kA.