JPH0325808A - Superconductor - Google Patents

Abstract

PURPOSE:To provide a superconductor of which pressure rise at the time of quench is small and of which loss by the eddy current at the time of a large change of the magnetic field is small by using copper or aluminium as the base material of a conduit of the most inside layer, and inserting high resistance members into the base material locally. CONSTITUTION:A conduit consists of an outside layer 2B and an inside layer 2C, and a superconductive wires 1 are housed in the conduit. The inside layer 2C of the conduit is formed with high resistance layers 3 to prevent the eddy current flowing in the inside layer 2C of the conduit at the time of a change of the magnetic field with the high resistance layers 3, and the loss by the eddy current can be reduced remarkably. At the time of quench, since the base material of the inside layer 2C of the conduit is copper of which electric resistance is low, the electric current flowing in the superconductive wires are shunted to the inside layer 2C of the conduit, and the calorific value is reduced to restrict the pressure rise.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to cables used in large superconducting coils, etc.
Concerning in-conduit type superconducting conductors. (Prior technology) In cable-in-conduit type superconducting conductors that are cooled by flowing a refrigerant inside the conductor, the internal pressure may become extremely large when quenched. Therefore, it is being considered to make the conduit multi-layered, as shown in Figure 3, with each layer made of a low-resistance material such as copper or aluminum. (Problem to be solved by the invention) However, when conventional superconducting conductors are used in cases where magnetic field changes are large, there is a problem in that large eddy currents flow in the layer of material with low resistance, resulting in large losses. The present invention was made to solve the above-mentioned problems, and the pressure increase during quenching is small, and
The objective is to provide a superconducting conductor with low loss due to eddy current even when magnetic field changes are large. [Structure of the Invention] (Means for Solving the Problems) In the present invention, in order to achieve the above object, the conduit has a multilayer structure, and at least the innermost layer of the conduit has a base material of copper or aluminum. The structure includes high-resistance members.

(Function) In the superconducting conductor according to the present invention, when a magnetic field change occurs, the eddy current generated in the conduit of the layer with low electrical resistance is reduced by the member made of the material with high electrical resistance placed in that layer. (Example) Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a cross section of a superconducting conductor according to the present invention. In this embodiment, the conduit consists of an outer layer 2B and an inner layer 2C, in which the superconductor 4I1 is contained. The outer layer 2B is made of high-strength S to withstand electromagnetic force, pressure, etc.
The inner layer 2C is made of US material, and the inner layer 2C is made of copper, which has a low electrical resistance, as a base material, and the high resistance layer 3 is made of CuNi, which has a large electrical resistance in the longitudinal direction of the conductor. By attaching the high resistance layer 3 to the conduit inner layer 2C,
The high resistance layer 3 prevents eddy currents from flowing in the conduit M2G when a magnetic field change occurs, and losses due to eddy currents can be significantly reduced.

In addition, when quenching occurs, since the conduit inner layer 2C has a base material of copper with low electrical resistance, the current flowing through the superconducting wire is diverted to the conduit inner layer 2C, reducing the amount of heat generated and suppressing the pressure rise. This is similar to the conventional superconducting conductor shown in Figure 3. In addition, the conduit inner layer 2C is
US, the superconducting conductor of the present invention can be obtained even if the outer conduit 2B is made of copper having a high resistance layer 3. Further, by forming the high resistance layer 3 in a spiral shape in the longitudinal direction of the conductor, the effect of preventing eddy currents can be enhanced. (Other Embodiments) FIG. 2 is a diagram showing a cross section of a superconducting conductor according to another embodiment of the present invention. In this example, the conduit inner layer 2D is made of copper with low voltage resistance, and the high resistance layer 4 along the longitudinal direction of the conductor is formed by filling CuNi into a groove machined on the surface of the conduit inner layer 2D. ．． According to this embodiment, the airtightness of the conduit inner layer 2D is improved, and workability is also improved. [Effects of the Invention] As detailed above, the present invention provides a cable insulator that can reduce loss due to eddy current when magnetic field changes occur and also suppress pressure rise when quenching. - Can provide conduit type superconducting conductors.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a superconducting conductor according to an embodiment of the present invention, Fig.
The figure is a cross-sectional view of a superconducting conductor according to another embodiment, and FIG. 3 is a cross-sectional view of a conventional superconducting conductor. 1...Superconducting wire

Claims (2)

[Claims] (1) In a cable-in-conduit type superconducting conductor in which a superconducting wire is placed inside the conduit, the conduit has a multilayer structure with at least two layers, and at least the innermost layer of the conduit is made of copper or aluminum as a base material. , a superconducting conductor characterized by having a high-resistance material inserted into its base material. (2) The superconducting conductor according to claim (1), wherein the high resistance member is CuNi.