JPH04355010A - oxide superconductor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to oxide superconducting conductors.

0002

2. Description of the Related Art In recent years, yttrium-based, bismuth-based, and thallium-based oxide superconductors have attracted attention as superconducting materials exhibiting higher critical temperatures. Since these become superconducting at liquid nitrogen temperature (77.3 K), they are expected to be applied as current leads for cable conductors, busbar conductors, coils, and superconducting magnets.

[0003] Busbar conductors for large currents currently in use or scheduled to be used in the future include those with a carrying current of 30 KA to 45 KA.

0004

[Problems to be Solved by the Invention] However, when such a large current is passed through a single oxide superconducting conductor, the self-magnetic field becomes 3000 to 5000 Gauss, and under such a high magnetic field, the superconducting conductor The critical current density is 1/
It drops to 3 to 1/5.

An object of the present invention is to provide an oxide superconducting conductor in which the critical current density decreases little even when a large current is passed through it.

[0006]

[Means for Solving the Problems] The oxide superconducting conductor of the present invention is an oxide superconducting conductor in which a bundle of tape-shaped conductors is arranged in a ring shape in the circumferential direction along the longitudinal direction. , the bundles of adjacent conductors are arranged alternately so that the outgoing and returning paths of current flow, and the wide surfaces of the tape-shaped conductors are arranged substantially along the direction of the radiation extending from the center of the oxide superconducting conductor. It is characterized by

FIG. 1 is a sectional view showing an embodiment of the present invention. Referring to FIG. 1, fins 3 protruding outward are formed at equal intervals on the outer peripheral surface of a pipe-shaped external support 2, and between the fins 3, external conductor bundles 1 are arranged. It is provided.

This outer conductor bundle 1 is constructed by arranging tape-shaped conductors 1a in three rows in the vertical direction and stacking them.

A pipe-shaped internal support 5 is further provided inside the external support 2, and fins 6 are also provided on the outer peripheral surface of the internal support 5 at equal intervals. An inner conductor bundle 4 is provided between the fins 6. The inner conductor bundle 4 is constructed by stacking tape-shaped conductors 4a arranged in two rows in the vertical direction.

[0010] The outer conductor bundle 1 and the inner conductor bundle 4 have an outgoing (+) current path and an incoming current path (-) between adjacent conductor bundles.
They are arranged alternately so that

FIG. 2 is a sectional view showing the arrangement of tape-shaped conductors according to the present invention. In the embodiment shown in FIG. 1, the tape-shaped conductors 1a are arranged substantially along the direction of radiation extending from the center 7 of the oxide superconducting conductor, as shown in FIG. 4 which is a tape-shaped conductor of the inner conductor bundle
Similarly, the elements a are arranged toward the center 7 of the oxide superconductor.

0012

[Operation] FIG. 3 is a diagram showing the relationship between magnetic flux density and critical current density in a tape-shaped Bi-based superconductor. As shown in Figure 3, when the direction of the magnetic field is perpendicular to the wide surface of the tape-shaped Bi-based superconductor, the critical current density decreases compared to when the direction of the magnetic field is parallel to the wide surface. becomes significantly larger.

FIG. 4 is a diagram showing the direction of magnetic flux and the magnitude of magnetic flux density in a bundle of conductors arranged annularly in the circumferential direction. The results shown in FIG. 4 were obtained by magnetic field analysis of the oxide superconducting conductor having the structure shown in FIG.

As shown in FIG. 4, it can be seen that in the bundle of conductors, the magnetic flux density is large for the magnetic flux directed toward the center of the oxide superconductor and the magnetic flux directed outward from the center of the oxide superconductor. Therefore, according to the present invention, by arranging the wide surfaces of the tape-shaped conductors so as to substantially follow the direction of radiation extending from the center of the oxide superconducting conductor,
For each tape-shaped conductor, the magnetic flux density of the magnetic flux parallel to the wide surface is relatively large, and the magnetic flux density of the magnetic flux perpendicular to the wide surface is relatively small, so that the influence of the magnetic field as a whole can be minimized as much as possible. Can be done.

[0015]

[Example] An oxide superconductor as shown in Figure 1 was heated at 45K.
A magnetic field analysis is performed for the case where a current of A is applied,
When we analyzed the direction and magnitude of the magnetic flux that affected each tape-shaped wire, we found that the structure shown in FIG. 1 maintains a performance of 75% of the initial value when the magnetic field is 0.

FIG. 5 is a diagram showing an oxide superconducting conductor of a comparative example. In this comparative example, the outer conductor bundle 1 and the inner conductor bundle 1 each have tape-shaped conductors arranged and laminated in the horizontal direction. Therefore, the wide surfaces of each tape-shaped conductor are arranged perpendicularly to the center of the oxide superconducting conductor. In such a comparative example, 45
When a current of KA is applied, the performance becomes 60% as a result of magnetic field decomposition.

[0017]

[Effects of the Invention] As explained above, by following the present invention, even when a large current of several thousand amperes to tens of thousands of amperes is passed, performance deterioration due to the magnetic field is minimized and more current can be passed. can.

Further, according to the present invention, more current can flow per cross-sectional area of the conductor, so the cross-sectional area of the conductor can be reduced, and the conductor can be made more compact.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an arrangement of tape-shaped conductors according to the present invention.

FIG. 3 is a diagram showing the relationship between magnetic flux density and critical current density in a tape-shaped Bi-based superconducting wire.

FIG. 4 is a diagram showing the direction of magnetic flux and the magnitude of magnetic flux density in a bundle of conductors arranged annularly in the circumferential direction.

FIG. 5 is a diagram showing an oxide superconducting conductor of a comparative example.

[Explanation of symbols]

1 Outer conductor bundle 1a　Tape-shaped conductor 2 External support 3 Fin 4 Internal conductor bundle 4a　Tape-shaped conductor 5 Internal support 6 Fin

Claims (1)

[Claims] 1. An oxide superconducting conductor in which a bundle of tape-shaped conductors is arranged in an annular manner in the circumferential direction along the longitudinal direction, in which the bundle of tape-shaped conductors conducts an outgoing path and a return path of current between adjacent bundles of conductors. An oxide superconducting conductor characterized in that the tape-shaped conductors are arranged alternately so that .