Development of Ag-clad Bi-2223 superconductors for electric power applications

Development of high-temperature superconductor technology will make possible the design and fabrication of smaller, lighter and more efficient power devices such as motors, generators, transformers, transmission cables and fault-current limiters. A prototype fault-current limiter, a 200 hp motor and a 50 m long transmission cable have already been demonstrated using Ag-clad Bi-2223 superconductor tapes. We have recently enhanced the transport current properties of long lengths of multifilament Ag-clad Bi-2223 tapes through increased packing density of precursor powder, improved mechanical deformation, optimization of conductor design and adjusted cooling rate. These improved processing parameters had a pronounced effect on the transport critical current of the superconducting tapes. Our improvements are briefly discussed and their implications are assessed in this paper.