Transient Stability Characteristics of Parallel-Connected YBCO Coated Conductors for Power Transmission Cables

YBCO coated conductors are expected to be used in future high-temperature superconductor applications. For the application to power transmission cables, a number of YBCO coated conductors would be connected in parallel and they might be subjected to short-circuit fault currents. Therefore, in order to examine the stability and feasibility of YBCO power transmission cables, it is important to investigate the normal-zone initiation and propagation characteristics of the YBCO tapes and demonstrate the redistribution of transport current and the electromagnetic coupling between YBCO tapes during a short-circuit fault current. In this study, over-current pulses were applied to the two parallel-connected YBCO sample tapes in a liquid nitrogen bath, and the characteristics of the normal-zone initiation and propagation were examined experimentally. Additionally, we also show the experimental results of the redistribution of the transport current between parallel-connected YBCO sample tapes.