Critical current behavior of a BSCCO tape in the stacked conductors under different current feeding mode

• The critical current is measured for a three-layer BSCCO stacked conductor.
• The critical current strongly depends on the current feeding mode.
• Opposite-direction feeding mode leads to 50% increase of the critical current.
• Current feeding mode effect implies onto a manufacture of a flexible DC power cable.

In the 200 m high temperature superconducting cable test facility, BSCCO tapes with the critical current of 160 A in self field are used for the two superconducting conductors corresponding to each polarity of DC power transmission. In order to improve the cable property by tape configuration, we have investigated the critical current of a BSCCO tape with different structures. Previous study shows that the critical current of BSCCO tape decreases by 15% for the 3-layer stack structure. However, the stack structures are needed to obtain high current capacity of a cable. Therefore we study the performance of BSCCO tape in the stacked tapes conductor. The insulated tapes are arranged in a tape-above-tape structure and different currents are applied to each tape. The critical current of the target sample is measured by the four probe method by immersing the samples into liquid nitrogen bath. The experiments show that the improvement and degradation of the critical current of BSCCO tape in the stacked conductor are observed under different current feeding mode due to the magnetic field interactions between the tapes. The critical current of BSCCO in the stacked conductor is enhanced by 50% to more than 230 A under the opposite-direction current feeding mode.