Laminated wire type superconducting cable

Abstract

To enable higher currents in superconducting cables, the objective is to provide a wire-laminated superconducting cable that can suppress the degradation of current-carrying performance when increasing the number of superconducting wires used within the cable. [Solution] A superconducting cable A comprising a former 10 and at least one wire unit 20 arranged on the outer circumference of the former 10, wherein the wire unit 20 is constructed by arranging tape-shaped superconducting wires 30 having at least a substrate 31, an intermediate layer 32, a superconducting layer 33, and a stabilizing layer 34 such that the substrate 31-side faces of each superconducting wire 30 face outwards from each other, or by arranging two superconducting wires 30 so that the substrate 31-side faces of each superconducting wire 30 face each other. The wire unit 20 may be wound around the outer circumference of the former 10 or attached vertically. With this configuration, at least one of the following effects can be obtained: increased current capacity, improved strength, improved bending strength, and ensured current-carrying performance.

Description

Technical Field

[0001] The present invention relates to a wire laminated type superconducting cable having a wire unit formed by laminating a plurality of superconducting wires.

Background Art

[0002] In order to achieve a large current of the order of kA in a superconducting cable (hereinafter, may sometimes be simply referred to as "cable"), not only a method of improving the current characteristics per sheet of the superconducting wire accommodated in the cable (see Patent Document 1 etc.), but also a method of increasing the number of superconducting wires accommodated in the cable, for example, can be considered.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] One of the objects of the present invention is to provide a wire laminated type superconducting cable capable of suppressing a decrease in energization performance when increasing the number of superconducting wires accommodated in the cable in order to achieve a large current in the superconducting cable.

Means for Solving the Problems

[0005] The invention of the present application made to solve the above problems is a superconducting cable having at least a former and at least one wire unit disposed on the outer periphery of the former, wherein the wire unit has a tape shape, and in the tape thickness direction, a superconducting wire having at least a substrate, an intermediate layer, a superconducting layer and a stabilizing layer is laminated in a plurality of sheets in the thickness direction of the superconducting wire.

Effects of the Invention

[0006] According to the present invention, it is possible to achieve even higher current capacity in superconducting cables. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic diagram showing a first embodiment of the superconducting cable according to the present invention. [Figure 2] A schematic diagram showing the structure of a superconducting wire. [Figure 3] A schematic diagram showing an FFDS-type wire unit. [Figure 4] Functional schematic diagram of a superconducting cable using FFDS-type wire units. [Figure 5] A schematic diagram showing a BBDS-type wire unit. [Figure 6] Functional schematic diagram of a superconducting cable using BBDS-type wire units. [Figure 7] A schematic diagram showing the connection configuration between the end of a BBDS-type wire unit and the electrode section. [Figure 8] A schematic diagram showing a second embodiment of the superconducting cable according to the present invention. [Modes for carrying out the invention]

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. [Examples]

[0009] <1> Overall structure (Figure 1) The superconducting cable A according to the present invention is a component for connecting a power source to a superconducting device, or to superconducting devices themselves. In this invention, the term "superconducting cable" is not limited to a configuration in which a shield or insulator is provided on the conductor, but also includes a configuration consisting only of a conductor. Furthermore, the superconducting cable A according to the present invention is not limited to the three-phase coaxial type, but includes all forms.

[0010] The superconducting cable A according to the present invention comprises at least a former 10 and at least one wire unit 20 arranged on the outer circumference of the former 10 and functioning as a conductor. In addition, in the superconducting cable A shown in Figure 1, an insulating layer 40 is provided on the outer circumference of the wire unit 20. The following describes the details of the former 10 and the wire unit 20.

[0011] <2> Forma (Figure 1) Former 10 is a component to which the wire unit 20 is to be placed. In the present invention, the materials and structure of the former 10 are not particularly limited, and tubular members made of metals or alloys such as copper, aluminum, or stainless steel, or stranded wires made by twisting multiple metal wires together, can be used.

[0012] <3> Wire unit (Figure 1) The wire unit 20 is a component that is placed inside the superconducting cable A and functions as a conductor for transmitting power in a superconducting state.

[0013] <3.1> Arrangement of wire units In the present invention, the arrangement of the wire units 20 with respect to the former 10 is not particularly limited, and arrangements such as winding them around the outer circumference of the former 10 or attaching them vertically to the outer circumference of the former 10 can be adopted. In this embodiment, multiple wire units 20 are wound around the outer circumference of the former 10 such that the side edges of each wire unit 20 are adjacent to each other. Specifically, among the plurality of wire units 20, one wire unit 20 (hereinafter referred to as the "first wire unit") is wound in a spiral shape with a certain gap (pitch), and another wire unit 20 (hereinafter referred to as the "second wire unit") is wound with substantially the same pitch as the first wire unit so that the side edges are adjacent to each other with respect to the first wire unit. Similarly, it is wound around the outer periphery of the former 10 for the required number of wire units 20. After winding the required number of wire units 20, it is preferable to wind the plurality of wire units 20 around the outer periphery of the former 10 so that the wire unit 20 is in a state close to a perfect circle when looking at any cross-section in the axial direction of the superconducting cable A.

[0014] Here, "so that the side edges are adjacent to each other" means winding in a state where there is almost no gap, such as whether the side edges of each wire unit 20 abut or not. If each wire unit 20 is wound in a lapping manner, problems such as an increase in the AC loss of the superconducting cable A and damage to the wire unit 20 due to the generation of steps may occur. Also, if each wire unit 20 is wound with a gap, problems such as an increase in the AC loss of the superconducting cable A may occur. Therefore, in the present invention, it is preferable to wind the wire units 20 so that the side edges of each wire unit 20 are adjacent to each other.

[0015] <3.2> Configuration of Wire Unit The wire unit 20 is configured by laminating a plurality of superconducting wires 30 in the thickness direction of the superconducting wire 30. In the present invention, the superconducting wires 30 constituting the wire unit 20 may be integrally formed inseparably, or may be in a state of being overlapped in a separatable state as appropriate. Also, in the present invention, the number of superconducting wires 30 constituting the wire unit 20 is not particularly limited. In this embodiment, the wire unit 20 is composed of two superconducting wires 30.

[0016] <4> Superconducting Wire (Fig. 2) The superconducting wire 30 (hereinafter sometimes simply referred to as "wire 30") is a tape-shaped conductive member that constitutes the wire unit 20. In the present invention, the type of superconducting wire 30 is not particularly limited. In this embodiment, a tape-shaped MOD (Metal Organic Deposition Processes) type wire is used as the superconducting wire 30. The superconducting wire 30 shown in Figure 2 has at least a substrate 31, an intermediate layer 32, a superconducting layer 33, and a stabilizing layer 34 in the thickness direction of the wire 30, in order from bottom to top of the paper. The following provides a detailed explanation of each part.

[0017] <4.1> Substrate (Figure 2) The substrate 31 is the base layer for the superconducting wire 30. In the present invention, the type of substrate 31 is not particularly limited, but for example, an alloy can be used in which one or more elements selected from tungsten (W), tin (Sn), zinc (Zn), molybdenum (Mo), chromium (Cr), vanadium (V), tantalum (Ta), or titanium (Ti) are added to nickel (Ni) or copper (Cu).

[0018] <4.2> Intermediate layer (Figure 2) The intermediate layer 32 is provided between the substrate 31 and the superconducting layer 33 to prevent a reaction between the substrate 31 and the superconducting layer 33 during the heat treatment process when manufacturing the superconducting wire 30. In the present invention, the type and number of intermediate layers 32 are not particularly limited, but for example, ceria (CeO2) or manganese oxide (MgO) can be used.

[0019] <4.3> Superconducting layer (Figure 2) The superconducting layer 33 is the part that allows current to flow in a superconducting state. In the present invention, the type of superconducting layer 33 is not particularly limited, but for example, yttrium oxide superconductor (RE123) can be used. The superconducting layer 33 can be formed, for example, by the MOD method (Metal Organic Deposition Processes).

[0020] <4.4> Stabilization layer (Figure 2) The stabilization layer 34 is formed directly above the superconducting layer 33 and is a region intended to stabilize the superconducting layer 33. More specifically, the stabilization layer 34 is a component that bypasses current and disperses heat generated by fault current or AC current to prevent damage and performance degradation due to overheating. In the present invention, the type of stabilizing layer 34 is not particularly limited, but precious metals such as silver (Ag), gold (Au), platinum (Pt), or alloys thereof can be used, and it is especially preferable to use a metal with low resistance. Furthermore, it is preferable to provide a copper plating layer on the surface of the stabilization layer 34 from the viewpoint of ensuring an electrically conductive surface.

[0021] <5> Arrangement configurations of superconducting wires (Figures 3-5) The superconducting cable A according to the present invention can employ either an FFDS (Face to Face Double Stack) type or a BBDS (Back to Back Double Stack) type, or a combination thereof, as the arrangement of adjacent superconducting wires 30 in the stacking direction of each wire unit 20. The details of each configuration will be explained below. For the sake of clarity, the stabilization layer 34 will not be shown in the following explanation.

[0022] <5.1> FFDS type (Figure 3) FFDS type (Face to Face Double Stack) refers to a configuration in which, in a wire unit 20, two adjacent superconducting wires 30 are arranged with their superconducting layer 33-side faces (also called the "stabilization layer-side faces") facing each other, that is, the substrate 31-side faces of each superconducting wire 30 facing outwards.

[0023] <5.1.1> Conductivity Model Diagram (Figure 4) Figure 4 shows a conductive model diagram when multiple FFDS-type wire units 20 are arranged around the outer circumference of the former 10. In this configuration, where multiple FFDS-type wire units 20 are wound around a former 10, the conductive region C1, which consists of an aggregate of the superconducting layers 33 of the inner superconducting wire 30 constituting each wire unit 20, and the conductive region C2, which consists of an aggregate of the superconducting layers 33 of the outer superconducting wire 30, are in an adjacent positional relationship. Therefore, when viewed as a superconducting cable A, it appears as if a thick, ring-shaped conductive region is formed by the integration of both conductive regions C1 and C2.

[0024] <5.1.2> Effects of FFDS type In the superconducting cable A according to the present invention, when an FFDS type wire unit 20 is used, at least one of the effects and benefits described below can be obtained. (1) Depending on the number of layers of superconducting wires 30, the number of superconducting wires 30 used can be increased, which contributes to increasing the current capacity of the superconducting cable A. (2) Because the wire unit 20 has two substrates 31 (substrate regions B1 and B2 shown in Figure 4), its strength is simply improved compared to a single superconducting wire 30. (3) The two superconducting layers 33 (conductive regions C1 and C2 shown in Figure 4) are concentrated towards the center in the thickness direction of the wire unit 20, thereby improving the bending strength. (4) Since the two superconducting layers 33 (conductive regions C1 and C2 shown in Figure 4) are concentrated towards the center in the thickness direction of the wire unit 20, even if a localized defect exists in one of the superconducting layers 33, the current path is secured by bypassing the defect through the other superconducting layer, thereby suppressing a decrease in current conductivity.

[0025] <5.2> BBDS type (Figure 5) BBDS type (Back to Back Double Stack) refers to a configuration in which two adjacent superconducting wires 30 in a wire unit 20 are arranged with their substrate 31-side faces facing each other, that is, the superconducting layer 33-side face of each superconducting wire 30 (sometimes called the "stabilization layer side") faces outwards.

[0026] <5.2.1> Conductivity model diagram of BBDS type (Figure 6) Figure 6 shows a conductive model diagram when multiple BBDS-type wire units 20 are arranged around the outer circumference of the former 10. In this embodiment, in which multiple BBDS-type wire units 20 are wound around a former 10, the substrate region B1, which consists of an assembly of substrates 31 of the inner superconducting wire 30 that constitutes each wire unit 20, and the substrate region B2, which consists of an assembly of substrates 31 of the outer superconducting wire 30, are arranged to face each other. Furthermore, the conductive region C1, which consists of an assembly of superconducting layers 33 of the inner superconducting wire 30, and the conductive region C2, which consists of an assembly of superconducting layers 33 of the outer superconducting wire 30, form an inner and outer double-tube-like conductive region.

[0027] <5.2.2> Effects of BBDS type In the superconducting cable A according to the present invention, by using an FFDS-type wire unit 20, at least one of the effects described below can be obtained. (1) Depending on the number of layers of superconducting wires 30 that make up the wire unit 20, the number of superconducting wires 30 used can be increased, which contributes to increasing the current of the superconducting cable A. (2) Because the wire unit 20 has two substrates 31 (substrate regions B1 and B2 shown in Figure 6), its strength is simply improved compared to a single superconducting wire 30. (3) Since each superconducting layer 33 (conductive regions C1, C2 shown in Figure 6) is located on the outside of the wire unit 20, current can be easily passed through. For example, when connecting a superconducting cable to a superconducting device, if a configuration is adopted in which the end of the wire unit 20 is housed in a slit D1 formed in the electrode section D provided inside the connection terminal of the superconducting device, as shown in Figure 7, the superconducting layer 33 side of each superconducting wire 30 (also called the "stabilization layer side") will be in close proximity to the inner wall of the slit D1. As a result, it is easy to secure a current path (connection cross-sectional area), and electrical current deviation can be prevented, thereby suppressing a decrease in current conduction performance at the electrode section D. [Examples]

[0028] A second embodiment of the superconducting cable according to the present invention will be described with reference to Figure 8. In this embodiment of the superconducting cable A, multiple wire units 20 are arranged vertically around the outer circumference of the former 10. In this case, it is preferable to arrange the multiple wire units 20 vertically in the required number of wires so that there are no gaps between adjacent wire units 20, and so that the cross-section is close to a perfect circle, in order to prevent an increase in AC loss. The superconducting cable A according to this embodiment can also provide the same effects and advantages as the superconducting cable A according to Embodiment 1. [Explanation of Symbols]

[0029] A: Superconducting cable 10: Forma 20: Wire Unit 30: Superconducting wires 31: Circuit board 32: Middle Class 33: Superconducting layer 34: Stabilization layer 40: Insulating layer B1,B2: Board area C1,C2: Conductive area D: Electrode part D1: Slit

Claims

1. A superconducting cable having a former and at least one wire unit arranged on the outer circumference of the former, The aforementioned wire unit, The superconducting wire is characterized by being tape-shaped and having at least a substrate, an intermediate layer, a superconducting layer, and a stabilizing layer in the thickness direction of the tape, and being constructed by stacking multiple superconducting wires in the thickness direction of the superconducting wire. Superconducting cable.

2. The superconducting cable according to claim 1, characterized in that the wire unit comprises two superconducting wires arranged such that the substrate-side surfaces of each superconducting wire face outwards from each other.

3. The wire unit is characterized in that two superconducting wires are arranged so that the substrate-side surfaces of each superconducting wire face each other. The superconducting cable according to claim 1.

4. The at least one wire unit is characterized by being wound around or attached longitudinally to the outer circumference of the former. The superconducting cable according to claim 1.

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