DESIGN AND TESTING OF A PAIR OF CURRENT LEADS USING BISMUTH COMPOUND SUPERCONDUCTOR

The thermal behavior of current leads using an oxide superconductor for the low temperature portion has been studied. Numerical calculations predict a reduction of the necessary coolant flow rate and refrigerator input power. A pair of current leads has been manufactured where the low temperature portion consists of six sintered Bi compound cylindrical bars and the high temperature portion consists of a Cu wire bundle. The lead, cooled by gaseous helium along its entire length, is 0.9 m long and designed to carry 1 kA. The leads have been tested in the same arrangement as practical applications. Helium flow rate necessary to hold thermal equilibrium was about 80% of that for conventional copper leads. Our calculation shows that power consumption of the refrigerator to cool HTS current leads with optimum cooling scheme will be about 1/3 of that for conventional current leads.