JP2010287350A - Interconnection structure of superconducting cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an interconnection structure of a superconducting cable capable of alleviating resistance of a connection site in case of connection of superconducting cables equipped with a superconducting conductor layer with a superconducting thin film directed toward an inner periphery side of a core. <P>SOLUTION: In the interconnection structure, a pair of superconducting cables having superconducting conductor layers 113A, 113B at an outer periphery of formers 111A, 111B are connected with each other. The superconducting conductor layers 113A, 113B are structured by spirally winding superconducting wire rods 2A, 2B with superconducting thin films 26A, 26B formed on the substrates 22A, 22B so as the superconducting thin films 26A, 26B to be at an inner periphery side and the substrates 22A, 22B at an outer periphery side. Further, the structure is provided with a superconducting connection member for installation 5 intercalated between the both superconducting conductor layers of the both cables, and superconducting connection members for jointing 6A, 6B facing inner periphery faces of both the superconducting thin films 26A, 26B and the superconducting connection member for installation 5. End parts of the superconducting conductor layers 113A, 113B and the superconducting connection member for installation 5 are connected with the superconducting connection members for jointing 6A, 6B through conductive jointing materials 7A, 7B. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an intermediate connection structure for a superconducting cable. In particular, the present invention relates to an intermediate connection structure of a superconducting cable including a superconducting conductor layer in which a superconducting thin film of a superconducting wire is spirally wound toward an inner peripheral side of the cable.

  A superconducting cable is expected as an energy-saving technology because it can transmit a large amount of current with low loss compared to a normal conducting cable. Recently, demonstration tests of superconducting cables have been conducted for practical use.

  In general, as shown in FIG. 2, the superconducting cable has a heat insulating tube 10 having an inner tube 10B inside an outer tube 10A, and one or more cores 11 are housed in the inner tube 10B. The core 11 includes a former 111, a superconducting conductor layer 113, an insulating layer 115, a superconducting shield layer 117, and a protective layer 119 in order from the center toward the outer peripheral side.

  In order to construct a long-distance transmission line using such a superconducting cable, an intermediate connection structure for connecting the cables is required. Conventionally, a technique described in Patent Document 1 is known as a technique for constructing this intermediate connection (see Patent Document 1). In this technique, first, each end of a pair of superconducting cables to be connected is stepped off, and each layer constituting the core is exposed stepwise. Next, the end portions of the formers are inserted into the connecting sleeve and abutted, and the formers are compressed to connect the formers. On the other hand, a connection member is prepared in which a plurality of superconducting wires are temporarily fixed in parallel. Conductive adhesive layers such as solder paste are formed on both ends of the connection member. This connecting member is wound around the outer periphery of the connecting portion between the formers, and the conductive adhesive layers at both ends are placed on the superconducting conductor layers of the respective cores. And the outer periphery of the location in the connection member where the conductive adhesive layer is provided is heated with a heater so that the superconducting conductor layers of both cables are connected to each other via the connection member. As the connection member used here, a Bi-based oxide superconducting wire manufactured by a powder-in-tube method is used.

  On the other hand, there is a thin film superconducting wire shown in FIG. 3 as a wire constituting the superconducting conductor layer of the superconducting cable. In this superconducting wire 2, a superconducting thin film 26 is formed on a normal conducting substrate 22. The superconducting conductor layer is formed by spirally winding the superconducting wire 2 so that the substrate 22 is on the outer peripheral side and the superconducting thin film 26 is on the inner peripheral side (see Patent Document 2). If the superconducting thin film 26 is a superconducting conductor layer (hereinafter referred to as an inner winding conductor structure) facing the inner peripheral side of the core, a compressive strain acts on the superconducting thin film 26 on the inner side of the bending, and the substrate 22 on the outer side of the bending Since tensile strain acts on the critical current, the critical current is unlikely to decrease.

JP 2008-245477 A JP 2007-188844 A paragraph number 0007

  However, the above-described prior art does not disclose an intermediate connection structure suitable for connecting the superconducting cables having the inner winding conductor structure.

  It is assumed that the technique described in Patent Document 1 is applied to a superconducting conductor layer having an inner winding conductor structure. In that case, the conductive adhesive layer is heated by covering the outer periphery of the superconducting conductor layer of the inner winding conductor structure, and the superconducting conductor layers of both cables are connected to each other via the connecting member.

  However, in such a connection structure, the superconducting thin film is connected to the connecting member via a normal conducting substrate located on the outer peripheral side of the superconducting conductor layer. As a result, it is expected that the resistance at the connection location will increase.

  The present invention has been made in view of the above circumstances, and one of its purposes is to provide an intermediate connection structure of superconducting cables that can connect superconducting cables having an inner winding conductor structure with low resistance. It is in.

  The intermediate connection structure of the superconducting cable according to the present invention relates to an intermediate connection structure of a superconducting cable that connects a pair of superconducting cables having a superconducting conductor layer on the outer periphery of the former. The superconducting conductor layer is formed by winding a superconducting wire having a superconducting thin film on one side of the substrate in a spiral shape so that the superconducting thin film is on the inner peripheral side and the substrate is on the outer peripheral side, and the surface on the inner peripheral side. A conductor joining surface. This intermediate connection structure includes a superconducting connection member for installation, a superconducting connection member for bonding, and a conductive bonding material. The superconducting connection member for erection is a member interposed between the superconducting conductor layers of each cable, and has a first joint surface adjacent to the conductor joint surface. The joining superconducting connection member has a second joining surface that faces the conductor joining surface and the first joining surface. The conductive bonding material bonds between the conductor bonding surface and the second bonding surface and between the first bonding surface and the second bonding surface. And, in the middle of the current path formed between the superconducting thin film and the joining superconducting connecting member, and between the joining superconducting connecting member and the erection superconducting connecting member, an electrical resistance equal to or higher than the material of the substrate is applied. The present invention is characterized in that the material is not interposed.

  According to this configuration, an electrical resistance equal to or higher than the material of the substrate is formed in the middle of the current path formed between the superconducting thin film and the joining superconducting connecting member and between the joining superconducting connecting member and the erection superconducting connecting member. There is no intervening material. Therefore, when connecting the superconducting cables having the inner winding conductor structure, a low resistance connection structure can be constructed.

  In the intermediate connection structure of the superconducting cable of the present invention, the superconducting connecting member for installation includes a superconducting layer on one side of the substrate, and is wound around the outer periphery of the former so that the superconducting layer is on the inner peripheral side and the substrate is on the outer peripheral side. It can be mentioned.

  According to this configuration, the superconducting layer of the erection superconducting connection member is disposed toward the bonding superconducting connection member, and is disposed on the inner peripheral side of the erection superconducting connection member. Therefore, a high resistance substrate is not interposed between the superconducting connecting member for installation and the superconducting connecting member for bonding.

  In the intermediate connection structure of the superconducting cable of the present invention, the superconducting connecting member for joining includes a superconducting layer on one side of the substrate, and is wound around the outer periphery of the former so that the superconducting layer is on the outer peripheral side and the substrate is on the inner peripheral side. It can be mentioned.

  According to this configuration, the superconducting layer of the joining superconducting connection member is disposed toward the superconducting conductor layer and the superconducting connection member for installation, and is disposed on the outer peripheral side of the substrate of the joining superconducting connection member. Therefore, a high-resistance substrate is not interposed between the superconducting conductor layer and the joining superconducting connecting member and between the erection superconducting connecting member and the joining superconducting connecting member.

  In the intermediate connection structure of the superconducting cable of the present invention, it is mentioned that both the superconducting connecting member for erection and the superconducting connecting member for bonding include a superconducting wire having a superconducting filament embedded in a stabilizing material.

  According to this configuration, since the superconducting wire in which the superconducting filament is embedded in the stabilizing material is used, there is no high-resistance substrate on one side in any of the superconducting connecting members for erection and joining. Therefore, the superconducting connection member for erection / joining can be used for assembling the connection structure without distinguishing the front and back.

  In the intermediate connection structure of the superconducting cable according to the present invention, one of the superconducting connecting member for erection and the superconducting connecting member for joining comprises a superconducting wire having a superconducting thin film on one side of the substrate, and the other is superconducting embedded in a stabilizing material You may provide the superconducting wire which has a filament. In that case, the superconducting thin film of one connection member is set to a side close to the bonding surface of the other connection member, and the substrate is configured to be a side separated from the bonding surface of the other connection member.

  According to this configuration, a high-resistance substrate is not interposed between the superconducting thin film and the superconducting filament of the erection superconducting connection member and the joining superconducting connection member. Therefore, the intermediate connection structure of the superconducting cable can be constructed with low resistance. Also, since a superconducting wire having a superconducting filament embedded in a stabilizing material is used for one of the superconducting connecting member for installation and the superconducting connecting member for joining, the connecting member has a connection structure without distinguishing between the front and back sides. Can be used for assembly.

  In the intermediate connection structure of the superconducting cable of the present invention, when the superconducting conductor layer has a plurality of superconducting wires laminated in the radial direction, the end of the superconducting conductor layer is connected to the end of the superconducting wire on the outer layer side. For example, the superconducting thin film of each layer may be formed stepwise by making it longer in the cable shaft end direction than the end of the superconducting wire. In that case, the superconducting connection member for installation also has a laminated structure corresponding to each layer of the superconducting conductor layer. And what is necessary is just to comprise the superconducting connection member for construction of each layer short so that it may be arrange | positioned at the inner layer side.

  According to this configuration, when each superconducting cable to be connected includes a superconducting conductor layer having a laminated structure, the superconducting conductor layers of each layer of each cable can be appropriately connected. In particular, since the intermediate connection portion can be constructed so that each layer of the superconducting conductor layer and each layer of the superconducting connection member for installation do not overlap, an increase in resistance at the connection location can be prevented.

  In the intermediate connection structure of the superconducting cable of the present invention, a normal conductive connecting member for compressing and connecting the formers of each cable may be mentioned.

  According to this configuration, the formers can be easily and firmly connected to each other by the compression connection using the normal conductive connection member. Along with this, it is possible to bear the tension generated in the superconducting cable by the former, and to prevent the tension from acting on the superconducting conductor layer, the superconducting connecting member for installation, and the superconducting connecting member for joining.

  According to the intermediate connection structure of the superconducting cable of the present invention, it is possible to connect without connecting a substrate between the superconducting thin film of the superconducting conductor layer and the superconducting connecting member for joining and between the superconducting connecting member for joining and the superconducting connecting member for installation. The resistance at the connection point can be reduced.

It is a principal part longitudinal cross-sectional view of the intermediate connection structure of the superconducting cable which concerns on Embodiment 1 of this invention. It is a cross-sectional view of a superconducting cable. It is a schematic perspective view which shows the structure of a thin film superconducting wire.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
〔overall structure〕
An intermediate connection structure according to an embodiment of the present invention will be described with reference to FIGS. In each figure, the same reference numerals are assigned to the same members. As shown in FIG. 1, the intermediate connection structure of this example includes an end portion of a pair of superconducting cables, a normal conductive connecting member 4, a superconducting connecting member 5 for installation, a superconducting connecting member 6 for joining, And a conductive bonding material 7. In this connection structure, in order, the superconducting conductor layer 113A of one superconducting cable, one superconducting connecting member 6A for joining, the superconducting connecting member 5 for installation, the superconducting connecting member 6B for the other joining, and the superconducting conductor layer of the other superconducting cable A current path of 113B is formed. In the following description, the configuration of the superconducting cable and the superconducting conductor layer will be described first, and then the intermediate connection structure will be described.

[Configuration of each part]
<Superconducting cable and its end>
As shown in FIG. 2, the superconducting cable 1 has a structure in which three cores 11 are housed in a heat insulating tube 10. The heat insulating tube 10 is constituted by a heat insulating double tube in which the space between the outer tube 10A and the inner tube 10B is evacuated, and a radiation heat insulating material (not shown) is disposed between the outer tube 10A and the inner tube 10B. On the other hand, the core 11 includes a former 111, a superconducting conductor layer 113, an insulating layer 115, a superconducting shield layer 117, and a protective layer 119 in order from the center toward the outer peripheral side.

  Among these, the superconducting conductor layer 113 has a configuration in which a plurality of superconducting wires are spirally wound around the outer periphery of the former 111 to form a single layer, and a plurality of the single layers are stacked in the radial direction of the core 11. This superconducting wire has a superconducting thin film 26 as shown in FIG. For example, the superconducting wire 2 having a laminated structure in which the intermediate layer 24, the superconducting thin film 26, and the stabilizing layer 28 are sequentially formed on one surface of the substrate 22 is used. However, the substrate 22 and the superconducting thin film 26 may be provided, and other layers may be provided as necessary. Each superconducting wire 2 is spirally wound so that the superconducting thin film 26 is on the inner peripheral side of the core 11 (FIG. 2) and the substrate 22 is on the outer peripheral side.

  At the end of such a superconducting cable, the layers from the former 111 constituting the core 11 to the superconducting shield layer 117 are exposed stepwise. The former 111 is a stranded wire composed of a plurality of copper wires, and the superconducting wire 2 constituting the superconducting conductor layer 113 and the superconducting shield layer 117 is a RE123-based wire (RE: rare earth elements such as Y, Ho, Nd, Sm, Gd, etc.), and PPLP (registered trademark) in which polypropylene and kraft paper are laminated can be used for the insulating layer 115. In particular, the superconducting conductor layer 113 uses the superconducting wire 2 in which the superconducting thin film 26 (FIG. 3) is spirally wound toward the inside of the core, so that the former 111 having a small outer diameter of, for example, 10 mm or less is used. Thus, the superconducting wire 2 can be wound. Furthermore, Hastelloy or the like can be used for the substrate 22 of the superconducting wire 2, YSZ or the like can be used for the intermediate layer 24, and Ag or Cu can be used for the stabilization layer 28.

  Among them, each layer of the superconducting conductor layers 113A and 113B of the laminated structure in each cable is configured so as to become longer in the cable shaft end direction (center side in FIG. 1) sequentially from the outer layer to the inner layer as shown in FIG. Is done. In other words, the ends of each layer of the superconducting conductor layers 113A and 113B are such that the superconducting thin films 26A and 26B face the inner peripheral side of the core with respect to the substrates 22A and 22B, and the superconducting wire substrates 22A and 22B on the inner layer side are the outer layers. It is formed so as to be exposed stepwise from the ends of the superconducting wires 2A and 2B on the side. Then, the inner peripheral surface of the end portion of each of the superconducting conductor layers 113A and 113B becomes a conductor bonding surface. Since the process of forming the end portions of the superconducting conductor layers 113A and 113B in a stepwise manner may be the same process as the so-called step peeling generally performed at the end of the cable, no special skill is required. If necessary, the superconducting thin films 26A and 26B are removed by mechanically or chemically removing the stabilization layer 28 (see FIG. 3) on the superconducting thin films 26A and 26B at the ends of the superconducting conductor layers 113A and 113B. The superconducting conductor layers 113A and 113B may be exposed on the inner peripheral side. Thereby, a connection structure with a lower resistance can be configured.

  In FIG. 1, for convenience of explanation, the stage states of the superconducting wires 2A and 2B at the ends of the superconducting conductor layers 113A and 113B are exaggerated. In general, the thickness of one superconducting wire 2A, 2B is about 100 to 200 μm. Although omitted in FIG. 1, interlayer insulation is provided between the layers of the superconducting conductor layer 113A (113B), and the thickness thereof is about 140 μm. On the other hand, in this example, of the pair of superconducting wires 113A (113B) adjacent in the radial direction of the core, the dimension (protrusion amount) of the inner layer protruding in the cable shaft end direction from the outer layer is about 20 to 30 mm. Therefore, at the end of the actual superconducting conductor layers 113A and 113B, the amount of protrusion is almost 100 times or more than the thickness of one superconducting wire 2A and 2B, and one step is about 240 to 340 μm. A state is formed.

<Normal conductive connection member>
The normal conducting connection member 4 is a member for connecting the formers of each cable. In this example, a copper sleeve material is used as the normal conducting connection member 4. The formers 111A and 111B of the respective cables are brought into a state of being inserted into and abutted from both ends of the normal conductive connection member 4, and the normal conductive connection member 4 is compressed and connected in this state.

  The outer peripheral surface of the normal conducting connection member 4 is formed in a stepped shape with both end portions being thin and the middle portion being thick. In this example, the level difference substantially corresponds to the thickness of the superconducting connection members 6A and 6B for bonding described later. By this step, (1) positioning of superconducting connection members 6A and 6B for joining to the innermost superconducting conductor layer, (2) superconducting connection members 6A and 6B for joining ride on the outer periphery of normal conducting connection member 4 Thus, it is possible to suppress excessive pressing at the end portion of the normal conductive connecting member 4 and (3) prevent increase in the outer diameter size of the riding position. The shapes of both end portions of the normal conducting connection member 4 may be tapered so that the outer diameter decreases toward the end portion.

<Superconducting connection member for installation>
The superconducting connecting member 5 for installation is one of the members for connecting the superconducting conductor layers 113A and 113B of both cables, and is interposed between the superconducting conductor layers 113A and 113B of each layer in both cables and is connected to the normal conducting connection. The outer periphery of the member 4 is covered. This erection superconducting connection member 5 includes a substrate 52 and a superconducting layer 56. Typically, a superconducting connection member 5 having a four-layer structure similar to the superconducting wires 2A and 2B constituting the superconducting conductor layers 113A and 113B can be used.

  Usually, a superconducting wire is manufactured by first producing a long sheet in which an intermediate layer, a superconducting thin film, and a stabilizing layer are sequentially formed on a substrate, and then cutting the long sheet into a predetermined wire width. Yes. Therefore, the superconducting connection member 5 for installation can be easily obtained by adjusting the cutting width of the long sheet. In this case, the long sheet substrate becomes the superconducting connection member substrate 52 and the long sheet superconducting thin film becomes the superconducting layer 56 of the superconducting connection member.

  The superconducting connecting member 5 for installation is a sheet having a width substantially corresponding to the distance between the superconducting conductor layers 113A and 113B in each cable and a length corresponding to the circumferential length of each layer of the superconducting conductor layers 113A and 113B. A plurality of superconducting wires having a length substantially corresponding to the distance between the superconducting conductor layers 113A and 113B in each cable may be arranged in parallel, and the total length in the parallel direction is the superconducting conductor layers 113A and 113B of each layer. You may comprise so that it may become the length corresponded to this perimeter. In that case, it is preferable that the superconducting wires arranged in parallel are integrated with a temporary fixing member that is stretched in a direction intersecting with the wires. Thereby, when the superconducting connecting member 5 for installation is arranged at a predetermined position of the intermediate connecting structure, it is possible to prevent each superconducting wire from being scattered. Further, when the superconducting connecting member 5 for construction is composed of a plurality of superconducting wires, the width of the superconducting wires may be the same as or different from the superconducting wires 2A and 2B constituting the superconducting conductor layers 113A and 113B. In this example, the superconducting connecting member 5 for erection is configured by arranging superconducting wires wider than the superconducting wires 2A and 2B constituting the superconducting conductor layers 113A and 113B in parallel. As a result, the number of superconducting wires constituting the superconducting connection member 5 for each layer is smaller than the number of superconducting wires 2A and 2B constituting the superconducting conductor layer of each layer, and the superconducting connection member 5 for construction and the superconducting connection for joining It is possible to reduce the number of places where the conductive bonding materials 7A and 7B are joined to the members 6A and 6B.

  By using the erection superconducting connection member 5 of such a size, the length of the core in the axial direction becomes shorter as the erection superconducting connection member 5 on the inner layer side. Accordingly, it is possible to avoid the superconducting connection member 5 for each layer from overlapping the superconducting conductor layers 113A and 113B of each layer.

  The superconducting connection member 5 for installation is arranged with the superconducting layer 56 facing the inner peripheral side of the core and the substrate 52 facing the outer peripheral side of the core. With this arrangement, the inner peripheral surfaces of the superconducting connection members 5 for construction of each layer in the core axial direction become the first joint surfaces. As a result, the conductor bonding surfaces in each of the superconducting conductor layers 113A and 113B and the first bonding surfaces in each layer of the superconducting connection member 5 for construction are adjacent to each other in the core axis direction.

<Superconducting connection member for bonding>
The superconducting connection members 6A and 6B for joining are members for electrically connecting the superconducting conductor layers 113A and 113B of each layer and the superconducting connection member 5 for construction of each layer. The superconducting connecting members 6A and 6B for joining are arranged so as to straddle the conductor joining surface and the first joining surface on the inner peripheral side of the superconducting conductor layers 113A and 113B and the superconducting connecting member 5 for installation. This joining superconducting connection member 6 also includes a substrate 62 and a superconducting layer 66. Typically, similarly to the superconducting wires 2A and 2B constituting the superconducting conductor layers 113A and 113B, a four-layer structure can be used as the joining superconducting connection members 6A and 6B. In this example, a long sheet in which an intermediate layer, a superconducting thin film, and a stabilizing layer are sequentially formed on a substrate is manufactured, and the long sheet is cut into a width of about 30 mm to form a superconducting connection member 6 for bonding. Further, the lengths of the superconducting connecting members 6A and 6B for joining are substantially equivalent to the peripheral lengths of the superconducting conductor layers 113A and 113B of the respective layers.

  Such joining superconducting connection members 6A, 6B are arranged along the circumferential direction of the core, with the substrates 62A, 62B facing the inner peripheral side of the core and the superconducting layers 66A, 66B facing the outer peripheral side of the core. It is wound around. At that time, the outer peripheral surface of the superconducting connection members 6A and 6B for bonding is the second bonding surface, and almost half of the width direction of the second bonding surface faces the conductor bonding surfaces of the respective layers of the superconducting conductor layers 113A and 113B, and the remaining Half is made to face the first joint surface of the superconducting connection member 5 for installation. Due to the arrangement of the superconducting connecting members 6A and 6B for joining, the superconducting thin films 26A and 26B of the superconducting conductor layer and the superconducting layers 66A and 66B of the superconducting connecting member for joining and the superconducting layer 56 of the superconducting connecting member for joining are used for joining. The substrates 22A, 22B, 52, 62A and 62B are not interposed between the superconducting layers 66A and 66B of the superconducting connection member. Due to the arrangement of the superconducting connecting members 6A and 6B for joining, the superconducting thin films 26A and 26B of the superconducting conductor layer and the superconducting layer 56 of the superconducting connecting member for installation are interposed through the superconducting layers 66A and 66B of the superconducting connecting member for joining. Are electrically connected.

<Conductive bonding material>
The conductive bonding materials 7A and 7B are used for bonding between the conductor bonding surface of each layer of the superconducting conductor layers 113A and 113B and the second bonding surface of the superconducting connecting member for bonding, and the first bonding surface of each layer of the superconducting connecting member for installation. Used for joining between the second joining surfaces of the superconducting connection members 6A and 6B. Specifically, solder can be used. Low melting point solder may be used. The superconducting thin film 26A, 26B of the superconducting conductor layer and the superconducting layers 66A, 66B of the superconducting connecting member for joining and the superconducting layer 56 of the superconducting connecting member for joining and the superconducting superconductor for joining are obtained by joining with the conductive joining materials 7A, 7B. Only the solder and the stabilization layer 28 (FIG. 3) are interposed between the superconducting layers 66A and 66B of the connection member, and the high resistance substrates 22A, 22B, 52, 62A and 62B are not interposed. Even a material other than solder can be used as the conductive bonding materials 7A and 7B as long as these bonding points can be connected with low resistance and mechanically suitable bonding strength can be obtained.

[Assembly method]
The above intermediate connection structure of the present invention is assembled as follows.

  First, the ends of the pair of superconducting cables 1 (see FIG. 2) are stepped off, and the layers from the former 111 constituting the core 11 to the superconducting shield layer 117 are exposed stepwise. At this stage, the end portions of each layer of the superconducting conductor layer 113 are all set to the same length.

  Next, from the end portions of the superconducting conductor layers 113A and 113B (FIG. 1), the superconducting wires 2A and 2B of each layer wound spirally are once spread and unwound.

  On the other hand, the former 111A of one cable is inserted from one end side of the normal conducting connecting member 4, the former 111B of the other cable is inserted from the other end side, and the end faces of both the formers 111A and 111B are connected to the normal conducting connecting member 4 (Fig. 1). In this state, the normal conducting connection member 4 is compressed by a compressor. This compression is performed on the middle part of the normal conducting connection member 4. By this compression, the formers 111A and 111B are compressed and connected by the normal conducting connection member 4.

  Then, the edge part of the superconducting wire of each layer which was unraveled is cut | disconnected. Specifically, the superconducting wires 2A and 2B in each layer are cut by taking a larger cutting allowance for the superconducting conductor layers 113A and 113B on the outer layer side. At that time, of the pair of superconducting conductor layers 113A and 113B adjacent in the radial direction of the core, the protruding amount of the inner layer protruding in the core axial direction from the outer layer is about half of the width of the superconducting connecting members 6A and 6B for bonding. Select the cutting allowance to correspond to. By this cutting, each of the superconducting conductor layers 113A and 113B is configured so as to become longer in the cable shaft end direction from the outer layer toward the inner layer.

  When this cutting is finished, a superconducting connecting member for bonding is arranged on the inner peripheral side of the end portion of each superconducting conductor layer 113A, 113B. The arrangement of the superconducting connection members for bonding is such that the superconducting connection members 6A and 6B for bonding are arranged in the circumferential direction of the core so that the superconducting layer 66 faces the outer peripheral side of the core and the substrate 62 faces the inner peripheral side of the core. It is done by making a round along.

  First, the superconducting connection members 6A and 6B for bonding on the inner layer side are wound around the outer periphery near the boundary between the formers 111A and 111B and the normal conductive connection member 4. At that time, a part of the joining superconducting connecting members 6A and 6B in the width direction is fitted into a step formed at the end of the normal conducting connecting member 4. Thereafter, the superconducting wires 2A and 2B on the inner layer side that have been unwound are restored. As a result, the conductor joint surfaces of the wire rods 2A and 2B are made to face a region about half the outer peripheral surface (second joint surface) of the superconducting connection members 6A and 6B for joining.

  Next, the superconducting connecting member 5 for installation is interposed between the superconducting layer layers 113A and 113B on the inner layer side in both cables. The erection superconducting connection member 5 is arranged so as to go around the outer periphery of the normal conductive connection member 4 with the substrate 52 facing the outer peripheral side of the core and the superconducting layer 56 facing the inner peripheral side of the core. And the inner peripheral surface at both ends of the superconducting connection member 5 for installation, that is, the first joint surface is a region of the second joint surface of the superconducting connection members 6A and 6B that is not covered with the superconducting wires 2A and 2B. Face to face.

  Subsequently, the conductive bonding members 7A and 7B are bonded between the conductor bonding surface and the second bonding surface and between the first bonding surface and the second bonding surface. Either “between the conductor bonding surface and the second bonding surface” or “between the first bonding surface and the second bonding surface” may be bonded first by the conductive bonding members 7A and 7B.

  Similarly, for the superconducting conductor layers 113A and 113B on the outer layer side, the arrangement of the superconducting connection members 6A and 6B for bonding, the arrangement of the superconducting connection member 5 for installation, the conductor bonding surface and the first bonding surface and the second bonding surface Bonding by the conductive bonding members 7A and 7B is sequentially performed. At that time, it is preferable to provide interlayer insulation between the superconducting connection member 5 for erection on the inner layer side and the superconducting connection member 5 for erection on the outer layer side.

  After completing the same connection for all the superconducting conductor layers 113A, 113B, in the region from the superconducting conductor layer 113A of one cable to the superconducting conductor layer 113B of the other cable through the superconducting connection member 5 for installation, Do not reinforce the insulation layer.

[Function and effect]
According to such an intermediate connection structure of the present invention, when connecting cables having a superconducting conductor layer of an inner winding conductor structure, a current between the superconducting thin film of the superconducting conductor layer and the superconducting layer of the superconducting connecting member for installation is provided. There is no high resistance substrate in the path. As a result, the resistance at this joint can be reduced.

  In addition, since the conductor joint surface of each layer of the superconducting conductor layer and the first joint surface of the superconducting connecting member for installation are arranged adjacent to each other, an intermediate connection structure can be configured without almost bending the superconducting wire of each layer. Therefore, distortion due to bending does not easily act on the end portion of each superconducting wire, and the size in the core radial direction at the connecting portion between the superconducting conductor layer and the superconducting connecting member for installation does not increase.

[Others]
In the above embodiment, only two superconducting conductor layers are shown, but the number of layers is not particularly limited, and may be a single layer or three or more layers. Further, the formers may be connected by welding the formers in place of the compression connection using the normal conducting connection member. The method of assembling the intermediate connection structure is not limited to the above procedure. For example, before compressing the normal conducting connection member, each layer of the superconducting conductor layer may be cut in advance to a predetermined length. Furthermore, it is also possible to prepare a composite in which the superconducting connection member for joining is joined to both ends of the superconducting connecting member for installation in advance with a conductive joining material, and the composite is interposed between the superconducting conductor layers of both cables. In addition, a superconducting connection member for bonding in which a solder paste is previously applied to the second bonding surface may be used. In that case, even if the superconducting conductor layer is a multilayer, the superconducting conductor layers of all the layers are arranged so that the second joining surface of the joining superconducting connecting member faces both the conductor joining surface and the first joining surface. . Thereafter, by heating from the outer periphery of the erection superconducting connection member, the superconducting conductor layers of all layers, the superconducting connection member for joining, and the superconducting connection member for erection can be joined together.

[Embodiment 2]
In the first embodiment, so-called thin film superconducting wires (sheets) are used for both the superconducting connecting member 5 for installation and the superconducting connecting members 6A and 6B for bonding. Instead, Bi-based superconducting wires manufactured by the powder-in-tube method are used. May be used. Usually, a Bi-based superconducting wire has a structure in which a plurality of superconducting filaments are embedded in a stabilizing material such as Ag or an Ag alloy, does not include a substrate of a thin film superconducting wire, and there is no distinction between front and back. Therefore, if a plurality of Bi-based superconducting wires are arranged in parallel to form the superconducting connecting member 5 for construction and the superconducting connecting members 6A and 6B for joining (FIG. 1), the superconducting conductor layers 113A and 113B and the superconducting connecting member 6A for joining are formed. 6B. The substrate 22A, 22B, 52, 62A, 62B is not interposed in the middle of the current path passing through the superconducting connection member 5 for installation, and a low resistance intermediate connection structure can be constructed. In addition, if the superconducting connecting member 5 for construction and the superconducting connecting members 6A and 6B for joining are formed of Bi-based superconducting wires, the intermediate connecting structure can be assembled without checking the front and back of these connecting members 5, 6A and 6B. Can do. If necessary, the plurality of Bi-based superconducting wires arranged in parallel may be integrated with a linear or sheet-like temporary fixing member that is stretched in a direction intersecting with these wires.

[Embodiment 3]
In the first embodiment, so-called thin film superconducting wires (sheets) are used for both the superconducting connecting member 5 for installation and the superconducting connecting members 6A and 6B for joining. However, the superconducting connecting member 5 for construction and superconducting connecting members 6A and 6B for joining are used. Any one of these may be replaced with a connecting member using the Bi-based superconducting wire. For example, when a thin film superconducting wire is used for the superconducting connection member 5 for installation and a Bi-based superconducting wire is used for the superconducting connection members 6A and 6B for bonding, the superconducting thin film of the superconducting connection member 5 for installation is connected to the inner peripheral side of the connection structure, The substrate should be on the outer peripheral side. In addition, when a Bi-based superconducting wire is used for the superconducting connecting member 5 for construction and a thin-film superconducting wire is used for the superconducting connecting members 6A and 6B, the superconducting thin film of the superconducting connecting members 6A and 6B is connected to the outer peripheral side of the connection structure. The substrate is set on the inner peripheral side. Also in these cases, the superconducting connecting member 5 for construction or the superconducting connecting members 6A and 6B for joining are configured by arranging a plurality of Bi-based superconducting wires in parallel. Also according to the third embodiment, it is not necessary to confirm the front and back of the connecting member 5 (6A, 6B) made of the Bi-based superconducting wire when assembling the intermediate connecting structure.

  The scope of the present invention is not limited to the above-described embodiment, and various modifications can be made.

  The intermediate connection structure of the superconducting cable of the present invention can be suitably used for connection between superconducting cables having a superconducting conductor layer having an inner winding conductor structure.

1 Superconducting cable
10 Insulated pipe
10A outer tube 10B inner tube
11 core
111, 111A, 111B Former 113, 113A, 113B Superconducting conductor layer
115 Insulation layer
117 Superconducting shield layer 119 Protective layer 2, 2A, 2B Superconducting wire
22, 22A, 22B Substrate 24 Intermediate layer 26, 26A, 26B Superconducting thin film
28 Stabilization layer 4 Normal conductive connecting member 5 Superconducting connecting member for installation
52 Substrate 56 Superconducting layer 6, 6A, 6B Superconducting connection member
62, 62A, 62B Substrate 66, 66A, 66B Superconducting layer 7, 7A, 7B Conductive bonding material (solder)

Claims (7)

An intermediate connection structure of superconducting cables for connecting a pair of superconducting cables having a superconducting conductor layer on the outer periphery of the former,
The superconducting conductor layer is formed by winding a superconducting wire having a superconducting thin film on one side of the substrate in a spiral shape so that the superconducting thin film is on the inner peripheral side and the substrate is on the outer peripheral side, and the surface on the inner peripheral side. A conductor joining surface
This intermediate connection structure
A member interposed between the superconducting conductor layers of each cable, and a superconducting connecting member for installation having a first joint surface adjacent to the conductor joint surface,
A superconducting connection member for joining having a second joint surface facing the conductor joint surface and the first joint surface;
A conductive bonding material for bonding between the conductor bonding surface and the second bonding surface and between the first bonding surface and the second bonding surface;
A material having an electrical resistance equal to or higher than the material of the substrate in the middle of a current path formed between the superconducting thin film and the joining superconducting connecting member and between the joining superconducting connecting member and the erection superconducting connecting member. An intermediate connection structure of a superconducting cable, characterized in that no intervening is present.   The superconducting connection member for installation includes a superconducting layer on one side of the substrate, and is wound around the outer periphery of the former so that the superconducting layer is on the inner peripheral side and the substrate is on the outer peripheral side. Intermediate connection structure of the described superconducting cable.   The superconducting connection member for bonding includes a superconducting layer on one side of a substrate, and is wound around the outer periphery of the former so that the superconducting layer is on the outer peripheral side and the substrate is on the inner peripheral side. The intermediate connection structure of the superconducting cable according to 2.   2. The superconducting cable intermediate connection structure according to claim 1, wherein both the superconducting connection member for installation and the superconducting connection member for bonding include a superconducting wire having a superconducting filament embedded in a stabilizing material. One of the superconducting connecting member for installation and the superconducting connecting member for bonding comprises a superconducting wire having a superconducting thin film on one side of the substrate, and the other comprises a superconducting wire having a superconducting filament embedded in a stabilizing material,
2. The superconducting thin film of one connection member is a side close to the joint surface of the other connection member, and the substrate is configured to be a side away from the joint surface of the other connection member. Intermediate connection structure of superconducting cable. In the superconducting conductor layer, a plurality of superconducting wires are laminated in the radial direction,
The end portion of the superconducting conductor layer is configured such that the end portion of the superconducting wire on the inner layer side is longer in the cable shaft end direction than the end portion of the superconducting wire on the outer layer side, and the superconducting thin film of each layer is configured in stages.
The erection superconducting connection member is a laminated structure corresponding to each layer of the superconducting conductor layer,
The intermediate connection structure for a superconducting cable according to any one of claims 1 to 5, wherein the superconducting connection member for erection of each layer is configured to be shorter as it is disposed on the inner layer side.   The intermediate connection structure for a superconducting cable according to any one of claims 1 to 6, further comprising a normal conductive connecting member that compressively connects the formers of the cables.

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