Quench protected structured superconducting cable
Quench protected structured (QPS) superconducting cables, methods of fabricating the same, and methods of bending the same are disclosed. The methods of bending the QPS superconducting cables can be employed to produce windings. The QPS superconducting cables can rapidly drive a distributed quench to a normal conducting state in a superconducting cable if a region of the cable spontaneously quenches during high current operation.
1. A method of bending a QPS superconducting cable, the QPS superconducting cable comprising: a spring tube; a plurality of superconducting wires disposed around the spring tube; and a sheath surrounding the plurality of superconducting wires and the spring tube, wherein the spring tube comprises a plurality of perforations,
wherein the method comprises the steps of:
evacuating the spring tube to create at least a partial vacuum;
filling the spring tube with water;
cooling the QPS superconducting cable to freeze the water;
bending the QPS superconducting cable;
warming the QPS superconducting cable to room temperature;
draining the water; and
evacuating the QPS superconducting cable to at least a partial vacuum to remove any residual water.
2. The method according to claim 1 , further comprising using a forming die to minimize sideways deformation.
3. The method according to claim 1 , wherein bending the QPS superconducting cable comprises bending the QPS superconducting cable to an angle of about 180°, with a ratio of radius of curvature (r c ) to sheath radius (r s ) (r c :r s ) of 7:1 or less.
4. The method according to claim 1 , wherein the plurality of superconducting wires includes at least one of the following materials: NbTi/Cu; Nb 3 Sn/Cu; Bi-2212/Ag; MgB 2 /Monel; ferropnictide; Bi-2223; YBCO; and rare-earth-based barium carbonates (ReBCO).
5. The method according to claim 4 , wherein each superconducting wire of the plurality of superconducting wires is cylindrical or is a flat ribbon.
6. The method according to claim 5 , wherein the sheath comprises any one of: a fiber-glass cloth; and a fiberglass tape applied to an outer surface of the plurality of superconducting wires.