Development of RE-123 Superconducting Cable

High temperature superconducting (HTS) cables are expected as a large capacity cable with lower transmission loss. Numerous HTS cable demonstration projects using Bi-2223 superconducting wires are being promoted around the world for practical utility usage. RE-123 coated conductors, which are still at the research and development stage, will also be applied to several demonstration projects in coming years in addition to Sumitomo Electric´s world first 30-m HTS cable project using RE-123 conductors which was successfully energized in early 2008. As wire and cable manufacturer, Sumitomo Electric has also been developing it´s own RE-123 conductors, and has succeeded in fabricating a 200-m-class conductor. One of the important challenges associated with the use of RE-123 conductors in power cables is to ensure stability against over-current. In order to evaluate over-current characteristics, a 10-meter ldquo3-in-Onerdquo RE-123 superconducting cable was manufactured and over-current tests were performed. No Ic degradation was observed after exposure to over-currents with a maximum current of 31.5 kArms for 2 s (120 cycles), which meets the requirements for 66-77 kV class power cables in Japan. It was confirmed that RE-123 conductors have satisfactory over-current characteristics for use as superconducting cable wires.