Effect of different core diameters on the current-carrying performance of CORC cables with REBCO multi-filamentary tapes

The second generation of high temperature superconductivity (HTS) is one of the candidate materials for future superconducting cables (such as CORC), CICC conductors and high field magnets due to its high current carrying performance and excellent mechanical strength. Currently, it has been demonstrated that the utilization of REBCO multi-filamentary tapes in the fabrication of CORC cables can further reduce AC losses. This study involved the preparation of various types of REBCO multi-filamentary tapes through reel-to-reel ultraviolet picosecond laser cutting technology, as well as the manual winding of multiple single-layer CORC cable samples. This work focused on the impact of core diameter on the current-carrying performance of REBCO multi-filamentary tapes under self-field conditions at 77 K. The results indicate that the critical current (I_C) of REBCO multi-filamentary tapes decreases as the core diameter decreases. Furthermore, the decrease in I_C becomes more significant with an increasing number of cores. When the cable core diameter is 4.6 mm, the critical current of the 3-filament tape is 180.49 A with an n-value of 24.84, which is only a 3.1 % recession compared to the critical current of the commercialized tape. The conclusion of this paper will provide a certain data reference for the subsequent selection of CORC cable core size prepared by REBCO multi-filamentary tapes.