Development of a 10 m long superconducting multistrand conductor for power transmission cables

A 10 m long HTS cable conductor was stranded with an industrial winding process from 2 km of Ag/Bi2223 tapes. It was installed in a vacuum cryostat and was force cooled by pressurized liquid nitrogen. DC- and AC-load tests were performed while varying the frequency and amplitude of the current. The critical current of the conductor is 5000 A. This model of a power transmission cable demonstrates very low AC losses of 0.8 W m(-1) at 2000 A(rms)/50 Hz measured both with an electric transport and a calorimetric method, The AC losses vary linearly with frequency, P proportional to f, and have a current dependence slightly lower than P proportional to I-3. The magnitude of the losses is clearly lower than predicted by the block model version of the Bean model. The model for uniform current distribution (UCD) improves the quantitative description of the losses. From these experiments we conclude that our low loss winding design of the conductor is an early stage of an economical HTS power transmission cable.