DEVELOPMENT OF A DOUBLE-STRANDED CABLE SUPERCONDUCTOR FOR 70 MW CLASSSUPERCONDUCTING GENERATOR WITH QUICK RESPONSE TYPE

We have been developing a 70 MW class model generator aiming at a 200 MW class pilot machine. The superconductor developed for field minding of generator hits a configuration of double stranded cable, composed of NbTi, Cu and CuNi. The strand is insulated by formvar and seven str ands make a 1st stage cable. Eleven 1st stage cables make a 2nd stage cable, and are compacted to rectangular cross section. The inter - str and resistance and A.C.loss of superconductors are measured under the conditions of compressive mechanical forte up to 19.6 MPa to simulate the centrifugal force of the generator rotor winding. From those resul ts, me consider the relation between inter - strand resistance and int er - strand coupling loss. Based on those results, ve are designing th e superconductors for the 70 MW class model generator with quick respo nse, taking the insulation of the strand into account.