66 kV-2 kA peak load test of high-T_c superconducting model cable

The superconducting power transmission cable is one of the most feasible applications for oxide superconductors. One case of introducing superconducting cables into power cable systems is as a replacement type in cable ducts, so that it is necessary to develop a compact superconducting cable which can be installed in existing ducts of diameter 150 mm. For this purpose, long-length Bi-2223 phase multifilamentary silver-sheathed wires with high critical current densities, such as over 7000 A cm^-2, have been developed and the effects of mechanical strain were investigated. As the next step, we have designed a 66 kV-2 kA superconducting cable of outer diameter 124 mm and developed a 5 m long model cable having a flexible conductor assembled by winding the foregoing wires in layers around a former. Furthermore, two different types of termination have been developed for a simultaneous current and voltage withstand test. As a result, we have been able to successfully perform a 66 kV-2 kA withstand test on an oxide superconducting power cable. The AC loss of the cable measured by the four-probe method was about 35 W m^-1. Moreover, generation of partial discharge in the cable was not observed at the test voltage.