A structure and method provide cables of high-temperature superconducting flat tape and/or filament wires, with a small bending diameter. A cable has a former having cross section that includes a rectangle having rounded ends (i.e. an obround), and the flat tape is wound around the surface of the former at an angle to minimize bending. The former surface may have raised helical ribs or lowered grooves to provide tape registration in multi-layer configurations. Tape may be wound from a spool onto the former under tension, and cut with a laser cutter to produce fine filaments immediately before winding. The former may be slit longitudinally to prevent loop eddy currents and reduce AC losses. The wound cable may be jacketed to provide a cable-in-conduit conductor (CICC), and coolant channels may be provided in the jacket or in the former.

A structure and method provide cables of high-temperature superconducting flat tape and/or filament wires, with a small bending diameter. A cable has a former having cross section that includes a rectangle having rounded ends (i.e. an obround), and the flat tape is wound around the surface of the former at an angle to minimize bending. The former surface may have raised helical ribs or lowered grooves to provide tape registration in multi-layer configurations. Tape may be wound from a spool onto the former under tension, and cut with a laser cutter to produce fine filaments immediately before winding. The former may be slit longitudinally to prevent loop eddy currents and reduce AC losses. The wound cable may be jacketed to provide a cable-in-conduit conductor (CICC), and coolant channels may be provided in the jacket or in the former.

A structure and method provide cables of high-temperature superconducting flat tape and/or filament wires, with a small bending diameter. A cable has a former having cross section that includes a rectangle having rounded ends (i.e. an obround), and the flat tape is wound around the surface of the former at an angle to minimize bending. The former surface may have raised helical ribs or lowered grooves to provide tape registration in multi-layer configurations. Tape may be wound from a spool onto the former under tension, and cut with a laser cutter to produce fine filaments immediately before winding. The former may be slit longitudinally to prevent loop eddy currents and reduce AC losses. The wound cable may be jacketed to provide a cable-in-conduit conductor (CICC), and coolant channels may be provided in the jacket or in the former.

A structure and method provide cables of high-temperature superconducting flat tape and/or filament wires, with a small bending diameter. A cable has a former having cross section that includes a rectangle having rounded ends (i.e. an obround), and the flat tape is wound around the surface of the former at an angle to minimize bending. The former surface may have raised helical ribs or lowered grooves to provide tape registration in multi-layer configurations. Tape may be wound from a spool onto the former under tension, and cut with a laser cutter to produce fine filaments immediately before winding. The former may be slit longitudinally to prevent loop eddy currents and reduce AC losses. The wound cable may be jacketed to provide a cable-in-conduit conductor (CICC), and coolant channels may be provided in the jacket or in the former.

In the connection portion for a superconducting wire, a plurality of superconducting wires are integrated by a sintered body containing MgB.sub.2, end portions of the superconducting wires each having an outer peripheral surface of a superconducting filament exposed are inserted into a container in parallel. The container has an opening having a diameter larger than a wire diameter of the superconducting wires on at least one side in a longitudinal direction of the superconducting wires, and the sintered body is in contact with the outer peripheral surfaces of the superconducting filaments. The method for connecting a superconducting wire includes: exposing the outer peripheral surfaces of the superconducting filaments; inserting the superconducting wires into the container; filling the container with a raw material; and heat-treating the raw material to generate the sintered body. The raw material is pressurized in parallel to the longitudinal direction of the superconducting wires and then heat-treated.

In the connection portion for a superconducting wire, a plurality of superconducting wires are integrated by a sintered body containing MgB.sub.2, end portions of the superconducting wires each having an outer peripheral surface of a superconducting filament exposed are inserted into a container in parallel. The container has an opening having a diameter larger than a wire diameter of the superconducting wires on at least one side in a longitudinal direction of the superconducting wires, and the sintered body is in contact with the outer peripheral surfaces of the superconducting filaments. The method for connecting a superconducting wire includes: exposing the outer peripheral surfaces of the superconducting filaments; inserting the superconducting wires into the container; filling the container with a raw material; and heat-treating the raw material to generate the sintered body. The raw material is pressurized in parallel to the longitudinal direction of the superconducting wires and then heat-treated.

A superconducting power cable having: a former including: an axially stretchable core, and a plurality of elongated outer elements wound helically around the core, wherein the core includes a first material and the elongated outer elements include a second material thermally contracting less than the first material at the operating temperature of the superconducting power cable; and a superconducting conductor layer arranged around the former.

The present invention provides: a compound superconducting twisted wire in which non-adhesiveness between compound superconducting strands or separation easiness after adhesion is improved while a strength against tension is improved to a degree to be equivalent to or stronger than that of a conventional compound superconducting twisted wire; and a rewinding method thereof. The compound superconducting twisted wire 1 of the present invention includes a plurality of compound superconducting strands 10 being twisted to form a twisted structure, in which each of the compound superconducting strands 10 includes a compound superconductor part 11, a reinforcing part 12 and a stabilizing part 13, in which the compound superconductor part 11 includes a plurality of compound superconducting filaments 15 and a first matrix 16, the compound superconducting filaments 15 each including a compound superconducting phase, in which the reinforcing part 12 is disposed on an outer circumferential side of the compound superconductor part, and comprises a plurality of reinforcing filaments 18 and a second matrix 19, in which the stabilizing part 13 is disposed on at least one side of an inner circumferential side and an outer circumferential side of the reinforcing part. In the compound superconducting twisted wire, a volume ratio of the reinforcing part relative to the compound superconducting strand is larger than a volume ratio of the compound superconductor part relative to the compound superconducting strand, or a metal layer 20 with a thickness of 2 μm or less is formed on a surface of the compound superconducting strand for preventing thermal fusion between the compound superconducting strands.

The present invention provides: a compound superconducting twisted wire in which non-adhesiveness between compound superconducting strands or separation easiness after adhesion is improved while a strength against tension is improved to a degree to be equivalent to or stronger than that of a conventional compound superconducting twisted wire; and a rewinding method thereof. The compound superconducting twisted wire 1 of the present invention includes a plurality of compound superconducting strands 10 being twisted to form a twisted structure, in which each of the compound superconducting strands 10 includes a compound superconductor part 11, a reinforcing part 12 and a stabilizing part 13, in which the compound superconductor part 11 includes a plurality of compound superconducting filaments 15 and a first matrix 16, the compound superconducting filaments 15 each including a compound superconducting phase, in which the reinforcing part 12 is disposed on an outer circumferential side of the compound superconductor part, and comprises a plurality of reinforcing filaments 18 and a second matrix 19, in which the stabilizing part 13 is disposed on at least one side of an inner circumferential side and an outer circumferential side of the reinforcing part. In the compound superconducting twisted wire, a volume ratio of the reinforcing part relative to the compound superconducting strand is larger than a volume ratio of the compound superconductor part relative to the compound superconducting strand, or a metal layer 20 with a thickness of 2 μm or less is formed on a surface of the compound superconducting strand for preventing thermal fusion between the compound superconducting strands.

Provided are: a superconducting wire rod in which the non-uniform deformation of the shape of an MgB.sub.2 core material has been controlled; a superconducting coil; a magnetic generator; and a method for producing a superconducting wire rod. A superconducting wire rod (100A) according to the present invention comprises: a center material (106) of which at least the outer circumferential surface is formed of a metal that does not react with Mg; a plurality of single-core wires (103) disposed around the center material (106), each of the single-core wires having an MgB.sub.2 superconductor core material (101) coated with a first coating material (102) made of a metal that does not react with Mg; and an outer shell material (105) disposed outside the plurality of single-core wires (103), wherein at least the inner circumferential surface of the outer shell material (105) is formed of a metal that does not react with Mg.