Design and Production of Efficient Current Leads for 1500-A, 50-Hz service in a 77-4 K Temperature Gradient

Two arrays of BSCCO 2223 bars were designed and produced for use in current leads for a power utility fault-current limiter operating at 4 K. Each conduction-cooled array, consisting of four parallel bars arranged within a 100-mm-diameter boundary, delivered 1500 A peak, 50-Hz AC through a 77-4 K temperature gradient while dissipating 5000 A/cm2 at 4 K. Magnetic field sensitivity was relatively low. Thermal conductivity tests showed values higher than literature values for polycrystalline BSCCO 2223 made by other processes.