JP2011045169A - Intermediate connection structure of superconducting cable - Google Patents

Abstract

An intermediate connection structure for a superconducting cable, which is excellent in workability at the time of connection and can reduce a loss due to energization.
In an intermediate connection structure, a pair of superconducting cables including an electrical insulating layer, a superconducting shield layer, and a normal conducting layer are connected in order to the outer periphery of a superconducting conductor. This intermediate connection structure 1A is composed of a superconducting wire, a superconducting connection part 20 that connects the superconducting shield layers 204, a superconducting connection part 20 is joined, and a copper support member 21A that is not joined to the normal conducting layer 205, And a normal conductive connection portion 3 made of copper and connecting the normal conductive layers 205 to each other. By providing the connection member between the superconducting shield layers 204 and the connection member between the normal conductive layers 205 separately, the connection work can be easily performed. By providing the superconducting connection portion 20 on the inner peripheral side of the support member 21A, even if a large current is passed, it is difficult for a shunt to occur in the support member 21A made of copper.
[Selection] Figure 1

Description

  The present invention relates to an intermediate connection structure of superconducting cables for connecting superconducting cables having a superconducting conductor and a superconducting shield layer. In particular, the present invention relates to an intermediate connection structure of a superconducting cable that facilitates connection work and easily reduces current loss at a connection point.

  Superconducting cables having superconducting conductors made of superconducting materials, particularly high-temperature superconducting materials that use liquid nitrogen as a refrigerant, are being developed. The superconducting cable typically includes a cable core having a superconducting conductor, an electrical insulating layer, and a superconducting shield layer in order from the inside, and a heat insulating tube that houses the cable core and is filled with the refrigerant. In the superconducting shield layer, during normal operation, a current of approximately the same magnitude is induced in the opposite direction to the current flowing through the superconducting conductor (conductor current), and the magnetic field due to the conductor current is canceled by the magnetic field due to this induced current (shield current), The leakage magnetic field to the outside of the superconducting cable can be made almost zero. There is also a superconducting cable that further includes a normal conducting layer made of copper on the outer periphery of the superconducting shield layer, and uses this normal conducting layer as a flow path for flowing an accident current in the event of a short circuit or the like (Patent Document 1).

  When constructing a superconducting cable line over a long distance, an intermediate connection for connecting different superconducting cables in the middle of the line is required. As an intermediate connection structure of a superconducting cable including the normal conductive layer, Patent Document 1 discloses a structure including a connecting shield member in which a superconducting wire is bonded to the surface of a cylindrical member made of copper. . More specifically, both ends of the cylindrical member are respectively connected to the normal conducting layers of the pair of superconducting cables to be connected, and both ends of the superconducting wire are respectively connected to the superconducting shield layers of the pair of superconducting cables to be connected. ing.

JP 2005-353379 A

  However, in the connecting shield member disclosed in Patent Document 1, since the tubular member and the superconducting wire are integral, it is difficult to connect the normal conducting layer included in the superconducting cable and the tubular member. Sometimes.

  For example, when the normal conducting layer is formed by winding a copper tape, the copper tape may have a curl and depending on the curl state, it may be difficult to join the tubular member. Therefore, when connecting superconducting cables having a normal conducting layer on the outer periphery of the superconducting shield layer, it is desired to improve workability at the time of connection.

  Further, it is desired to further increase the transmission capacity of the superconducting cable, and it is expected that a large capacity current such as 3000A class will flow. Even when such a large current flows, it is desired to develop an intermediate connection structure that can reduce loss (typically Joule loss) associated with energization.

  Accordingly, one of the objects of the present invention is to provide an intermediate connection structure for a superconducting cable that is excellent in workability during connection. Another object of the present invention is to provide an intermediate connection structure of a superconducting cable that can reduce a loss due to energization even when a large current flows.

  The present invention achieves the above object by using a member that connects the superconducting shield layers and a member that connects the normal conducting layers provided on the outer periphery of the superconducting shield layer as separate members that are not mechanically connected. To do.

  The present invention relates to an intermediate connection structure for a superconducting cable for connecting a pair of superconducting cables having an electric insulating layer, a superconducting shield layer, and a normal conducting layer in order on the outer periphery of the superconducting conductor. This intermediate connection structure is composed of a superconducting material, and is composed of a superconducting connection part that connects the superconducting shield layers of each of the superconducting cables, and a normal conducting material, and connects the normal conducting layers of each of the superconducting cables. A normal conductive connection portion; and a support member that is not connected to the normal conductive layer and is joined to the superconductive connection portion.

  In the conventional shield member for connection described above, the cylindrical member is configured to have both the support function of the superconducting wire and the electrical connection function between the normal conductive layers, and although the number of parts is small, the normal conductive layer as described above. It may be difficult to connect each other. In contrast, the intermediate connection structure of the present invention is a member that supports the superconducting connection part (support member) and a member that connects the normal conductive layers (normal conductive connection part) as independent members, and the support member is The mechanical connection is not made to the normal conductive layer. Accordingly, since the intermediate connection structure of the present invention can independently handle the member for connecting the superconducting shield layers and the member for connecting the normal conducting layers, the connection work between the superconducting shield layers and the normal conducting layers It is easy to perform the connection work separately, and the workability at the time of connection is excellent. In addition, superconducting materials, particularly oxide superconducting materials, are often brittle materials that are vulnerable to tension, etc., but in the intermediate connection structure of the present invention, the superconducting connection portion is joined to the support member to form an integral body. Stress due to thermal contraction when the superconducting cable is cooled can be received by the support member. Therefore, the intermediate connection structure of the present invention can prevent damage (breakage, breakage, etc.) of the superconducting connection part due to the stress or the like, and can be used satisfactorily for a long time after construction. That is, according to the intermediate connection structure of the present invention, during normal operation, the superconducting connection portion can sufficiently cause an induction current (shield current) to flow from the superconducting shield layer of one superconducting cable to the superconducting shield layer of the other superconducting cable. . In the intermediate connection structure of the present invention, in the event of an accident, an accident current can flow from the normal conducting layer of one superconducting cable to the normal conducting layer of the other superconducting cable by the normal conducting connecting portion.

  As one form of this invention, the said supporting member is comprised from copper, and the said superconducting connection part has the form joined to the superconducting conductor side in the said supporting member.

  Copper has a sufficient track record of use at the temperature of a refrigerant such as liquid nitrogen and a temperature in the vicinity thereof, and a reliable intermediate connection structure can be provided by using a component made of copper. However, since copper is a good conductor even at the temperature of the above-mentioned refrigerant, in particular, when using a large current of 3000 A class, an induced current is generated not only in a superconducting connection made of a superconducting material but also in a support member made of copper. It may diverge (a diversion will occur). A small amount of induced current flows through the support member made of copper, which causes a loss such as Joule loss. Moreover, there exists a possibility that the temperature of a connection location may rise by Joule heat. Here, since the connection place between the superconducting cables is provided with a reinforcing insulating layer or the like, heat tends to be generated more easily than the main line portion. Therefore, in the worst case, there is a risk of quenching (shifting from the superconducting state to the normal conducting state) due to the temperature rise at the connection location due to Joule heat. On the other hand, the induced current tends to flow more because the magnetic flux density is higher on the side closer to the conductor (inner peripheral side) that is the source of magnetomotive force. Therefore, by arranging the superconducting connection portion on the superconducting conductor side in the support member made of copper, the induced current flows preferentially to the superconducting connection portion, the amount of the shunting to the support member is reduced, and the loss due to energization is reduced. It can be effectively reduced.

As one form of the present invention, a form in which at least a part of the support member is made of a material having a specific resistance value (20 ° C.) of 1.0 × 10 ⁻⁶ Ω · m or more can be cited.

As described above, it is not a good conductor copper, but a material having a higher electrical resistance (specific resistance (20 ° C): approx.1.7 × 10 ^-8 Ω ・ m) than copper is used as a constituent material for the support member. The diversion to the member can be effectively reduced. Further, the constituent material of the support member is preferably a material having high mechanical strength. As a material satisfying the above specific resistance value and having higher strength than copper, for example, a metal material such as a copper alloy such as a Cu—Ni alloy (cupronickel) can be cited. Or the material normally treated as insulating materials, such as resin materials, such as glass fiber reinforced plastic (GFRP) and an epoxy resin, is mentioned. When the entire support member is composed of the high resistance material, the diversion can be effectively reduced. When the entire support member is composed of the insulating material, the diversion is substantially eliminated. be able to. Therefore, when the entire support member is composed of the high resistance material or the insulating material, the superconducting connection portion may be arranged on the inner peripheral side (superconducting conductor side) or the outer peripheral side of the support member.

As one form of the present invention, a form in which a part of the support member has an insulating portion made of a material having a specific resistance value (20 ° C.) of 1.0 × 10 ⁻⁶ Ω · m or more can be cited.

  For example, even if a part of the support member is made of copper, if the other part is made of a material that satisfies the above specific resistance value, the conductor cross-sectional area can be reduced, so that the amount of diversion can be reduced. . In particular, when the support member has a configuration in which the insulating portion is interposed between a region on one end side and a region on the other end side, and the both regions are electrically insulated by the insulating portion, In addition, as in the case where the entire support member is made of an insulating material or a high-resistance material, the shunt can be substantially eliminated.

  As one form of this invention, the said support member is a form which is a braid which becomes a cylindrical body combining a pair of half crack piece.

  According to the said structure, the support member by which the superconducting connection part was joined can be arrange | positioned easily in the outer periphery of the location which connected the superconducting conductors, and it is excellent in the workability | operativity at the time of constructing | attaching an intermediate connection structure. Moreover, a support member can exist so that the perimeter of the said connected location may be covered because the said support member is cylindrical. Therefore, this support member can sufficiently support the superconducting connection portion even when the superconducting connection portion is disposed around the entire circumference of the connected portion.

  As one form of this invention, the said support member is a cylindrical body, Comprising: The form which provides the arc-shaped slit provided along the circumferential direction is mentioned.

  Since the support member is cylindrical as described above, the entire circumference of the connected portion can be covered with the support member, and the superconducting connection portion can be sufficiently supported. And according to the said structure, by providing a slit, it is easy to infiltrate refrigerant | coolants, such as liquid nitrogen, inside a supporting member, and the said connected location which exists inside a supporting member can be cooled efficiently. The constituent material of the support member having the slit may be copper as described above, or a material having a higher specific resistance value than copper. In the case where the support member is made of a metal material such as copper or copper alloy, by providing the arc-shaped slit, there is a portion having a small cross-sectional area, so that the amount of diversion can be reduced. Therefore, according to this configuration, it is possible to effectively reduce the loss caused by the above-described diversion.

  As one form of this invention, the form which has the thin part in which the thickness of a part of said support member is thinner than the thickness of another part is mentioned.

  If the said supporting member can support the said superconducting connection part, the thickness can be selected suitably. In particular, when the support member is made of a metal material such as copper or copper alloy, the thickness is partially changed, i.e., by providing the thin portion, there is a portion having a small cross-sectional area. The amount can be reduced. Therefore, according to this configuration, it is possible to effectively reduce the loss caused by the above-described diversion.

  The intermediate connection structure of the superconducting cable of the present invention is excellent in workability at the time of connection. In particular, by devising the constituent material of the support member and the arrangement position of the superconducting connection part, it is possible to reduce the loss due to energization.

FIG. 1 is a partial longitudinal sectional view showing a schematic configuration of an intermediate connection structure of a superconducting cable of Embodiment 1. FIG. 2 is a transverse cross-sectional view showing a schematic configuration of a three-core collective superconducting cable. FIG. 3 is a front view showing a schematic configuration of a support member made of a plurality of different materials. FIG. 4 is a partial vertical cross-sectional view showing, in an enlarged manner, a schematic configuration of a connection portion between a superconducting cable and a shield connection portion in the superconducting cable intermediate connection structure according to the second embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. In the intermediate connection structure in FIGS. 1 and 4, only the upper half is shown from the center line, and the lower half is omitted. Moreover, the same code | symbol shows the same name thing in the following drawings.

(Embodiment 1)
Hereinafter, the intermediate connection structure of the superconducting cable according to the first embodiment will be described with reference to FIGS. This intermediate connection structure 1A connects a pair of different superconducting cables, and the feature thereof is that the superconducting shield layers 204 provided in each superconducting cable and the normal conducting layers 205 provided on the outer periphery thereof. Is in a structure to connect. Hereinafter, each configuration will be described in more detail.

[Superconducting cable]
First, a superconducting cable will be described. Here, a multi-core cable in which a plurality of cable cores are housed in one heat insulation pipe will be described, but a single-core cable in which a single core cable core is housed in one heat insulation pipe may be used. A superconducting cable 100 shown in FIG. 2 has a three-core cable core 101 twisted and housed in a heat insulating tube 102. Each cable core 101 includes a former 201, a superconducting conductor 202, an electrically insulating layer 203, a superconducting shield layer 204, a normal conducting layer 205, and a protective layer 206 in order from the center.

  The heat insulating tube 102 is a double structure tube composed of an inner tube 102i and an outer tube 102o, and is a vacuum heat insulating structure in which a vacuum is drawn between the inner tube 102i and the outer tube 102o. The inner tube 102i is filled with a refrigerant 103 such as liquid nitrogen, and the superconducting conductor 202 and the superconducting shield layer 204 of the cable core 101 are cooled by the refrigerant 103 and maintained in a superconducting state. On the outer periphery of the outer tube 102o, an anticorrosion layer 104 formed by extruding a material having excellent corrosion resistance such as polyvinyl chloride is provided.

  In addition to functioning as a support for the superconducting conductor 202, the former 201 is used for the flow path of a large accident current (short-circuit current) that occurs instantaneously when quenched due to an accident. Solid or hollow (tube) formed of the normal conductive material. Here, the solid body is formed by twisting a plurality of copper wires having an insulating coating such as enamel.

  The superconducting conductor 202 and the superconducting shield layer 204 are formed by, for example, winding a tape-like wire rod having an oxide superconductor, typically a Bi2223-based superconducting tape wire (Ag-Mn sheath wire) in a single layer or multiple layers in a spiral manner. It can be configured by doing. Here, the superconducting conductor 202 has a four-layer structure, and the superconducting shield layer 204 has a two-layer structure of an inner layer 204i (FIG. 1) and an outer layer 204o (FIG. 1). Between each layer, an interlayer insulating layer in which insulating paper such as kraft paper is wound can be provided. The superconducting conductor 202 is formed on the former 201, and the superconducting shield layer 204 is formed on the electric insulating layer 203 described later, and is located on the inner peripheral side of the normal conductive layer 205 described later, so that the superconducting state is maintained. In normal times, an induced current (shield current) flows easily.

  The electrical insulating layer 203 can be configured by winding a tape-like insulating material made of insulating paper such as kraft paper or semi-synthetic insulating paper in which kraft paper and plastic are combined. Here, it is made of semi-synthetic insulating paper (PPLP: registered trademark manufactured by Sumitomo Electric Industries, Ltd.). Further, the protective layer 206 can be formed by winding the craft paper or the like around the outer periphery of a normal conductive layer 205 described later.

  The normal conductive layer 205 is composed of the normal conductive material, like the former 201, because it is used mainly for a flow path of a large accident current that occurs instantaneously when quenched due to an accident or the like. Here, a copper tape is spirally wound in multiple layers on the superconducting shield layer 204.

  A pair of superconducting cables 100 having the above-described configuration is prepared, and the cable core 101 is pulled out from the end of each superconducting cable 100 and stepped off as shown in FIG. 1, and the former 201, the superconducting conductor 202, and the electric insulation layer 203 are prepared. Then, the superconducting shield layer 204 and the normal conducting layer 205 are exposed, and the intermediate connection structure 1A can be constructed by the procedure described later.

[Intermediate connection structure]
Next, the intermediate connection structure 1A will be described. The intermediate connection structure 1A is a structure provided at a location where the pair of cable cores 101 having the above-described configuration are connected to each other, and in particular, a member that connects the superconducting shield layers 204 to each other and a member that connects the normal conductive layers 205 to each other Are provided separately. Specifically, the intermediate connection structure 1A includes a shield connection part 2A that connects the superconducting shield layers 204 of the cable cores 101 and a normal conductive connection part 3 that connects the normal conductive layers 205 of the cable cores 101 to each other. Have.

《Shield connection part》
The shield connecting portion 2A is made of a superconducting material, and includes a superconducting connecting portion 20 that connects the superconducting shield layers 204 of the pair of cable cores 101 to be connected, and a support member 21A to which the superconducting connecting portion 20 is joined. . The support member 21A is a member that is not mechanically connected to the normal conductive layer 205 of the cable core 101 and is independent of the normal conductive connection portion 3.

  The superconducting connection portion 20 is composed of a superconducting wire similar to the superconducting wire constituting the superconducting shield layer 204. The support member 21A is a braid that becomes a cylindrical shape by combining a pair of semi-cylindrical divided pieces. More specifically, the support member 21A has a cylindrical shape at the center, and both ends thereof taper toward the periphery. In addition, the thickness of each divided piece constituting the support member 21A is substantially uniform from one end side to the other end side. Since the superconducting wire constituting the superconducting connection portion 20 is joined along the surface of the support member 21A, the tapered portion is inclined so that the superconducting wire is not excessively bent. Further, as shown in FIG. 1, the outer diameter of the support member 21A is such that a gap is provided between the outer peripheral surface of the electric field shielding layer 13 described later, and the length of the support member 21A in the longitudinal direction is It has a length that can sufficiently support the superconducting connection portion 20 passed between the pair of superconducting shield layers 204 to be connected. Here, the support member 21A is made of copper.

  A coolant such as liquid nitrogen is provided on the inner peripheral side of the support member 21A by appropriately providing holes and slits penetrating the front and back of each of the divided pieces, or by providing a slight gap between the divided pieces and fixing both divided pieces. You may make it easy to penetrate. The slit may be linear along the longitudinal direction of each divided piece, or may be arcuate along the circumferential direction of each divided piece. The arc-shaped slit reduces the cross-sectional area between the region on one end side and the region on the other end side of each divided piece. Therefore, even when a large current flows through the superconducting conductor 202, induction that occurs between both regions Current shunting can be reduced. The size of the hole (diameter and the like), the size of the slit (width and length), the number and the like can be appropriately selected. Note that the coolant impregnated in the cable core 101 of the superconducting cable is filled into the support member 21A via the components of the cable core 101 without providing a slit or the like.

  The superconducting wires are arranged in parallel along the circumferential direction of the inner peripheral surface of the support member 21A, and are joined by solder (which may be ordinary solder) so that the support member 21A and the superconducting wire are integrated. . That is, when the cross section of the shield connecting portion 2A is taken, the superconducting wires are arranged such that the end faces are arranged in a circular shape. By arranging the superconducting wire in a circular shape in this way, the superconducting wire can be disposed along the superconducting shield layer 204 disposed in a cylindrical shape, and the superconducting wire and the superconducting shield layer 204 are joined. Easy to do. The superconducting wire joined to the support member 21A is formed by laminating the inner wire 20i joined to the inner layer 204i of the superconducting shield layer 204 and the outer wire 20o joined to the outer layer 204o to join the support member 21A. Has been. Each of the inner wire 20i and the outer wire 20o has a length sufficient to cross over and join the inner layers 204i of the stepped superconducting shield layer 204, and the inner wire 20i is the outer wire. Shorter than 20o. In FIG. 1, the corner portions where the wire rods 20i and 20o are bent are shown in a square shape, but are actually bent gently so as to be bent.

《Normal conductive connection》
The normal conducting connection part 3 is preferably made of a material that is superior in mechanical strength to the superconducting wire constituting the superconducting connection part 20 and has a low electric resistance at the use temperature (refrigerant temperature) of the superconducting cable. Examples thereof include copper, aluminum, and alloys thereof. Here, a braided material made of copper wire is used which has a capacity (conductor cross-sectional area) that allows a large current such as an accident current to flow.

[Assembly procedure of intermediate connection structure]
Next, the assembly procedure of the intermediate connection structure 1A will be described. Introduce the ends of a pair of superconducting cables 100 to be connected to a connection box (not shown), strip the ends of the cable core 101 drawn from each cable 100, and form the former 201, the superconducting conductor 202, the electrical Insulating layer 203, superconducting shield layer 204, and normal conducting layer 205 are exposed. Then, the pair of formers 201 to be connected is inserted into the insertion hole of the copper connection sleeve 10 and compressed to connect the formers 201 to each other.

  Next, the superconducting conductors 202 included in the pair of cable cores 101 to be connected are connected by the connecting superconducting wire 11. The superconducting wire 11 for connection has a laminated structure in accordance with the superconducting conductor 202 having a four-layer structure. Each superconducting wire 11 for connection has a sufficient length that can be passed from one superconducting conductor 202 to the other superconducting conductor 202, and the length increases from the former 201 side toward the outer periphery. These connecting superconducting wires 11 are laminated in a stepped manner extending toward the outer peripheral side, one end of each connecting superconducting wire 11 is used as a superconducting layer constituting one superconducting conductor 202, and the other end is used as the other superconducting conductor. Each of the superconducting layers constituting 202 is joined with solder or the like. Each connecting superconducting wire 11 is preferably the same as the superconducting wire constituting the superconducting conductor 202. Further, when a reinforcing material (not shown) is disposed on the outer periphery of the outermost connecting superconducting wire 11, the reinforcing material shares the tension acting on the connecting sleeve 10 to further strengthen the intermediate connecting structure 1A. be able to. The constituent material of the reinforcing material may be the same material (for example, copper or aluminum) as the connection sleeve 10 or another material (for example, stainless steel). In addition, a part of the connecting sleeve may be compressed to connect the formers, and a superconducting wire constituting the superconducting conductor 202 may be inserted into the insertion hole of the connecting sleeve and connected by soldering.

  The reinforcing insulating layer 12 is formed so as to cover the outer periphery of the connecting superconducting wire 11, the superconducting conductor 202, and the electric insulating layer 203. The reinforced insulating layer 12 is wound with kraft paper or PPLP (registered trademark) so that the central part is cylindrical and both ends on the superconducting shield layer side are tapered toward the superconducting shield layer 204. Can be configured. In particular, the corner portion from the cylindrical portion toward the tapered portion and the portion on the distal end side of the tapered portion are at an angle at which electric field stress can be reduced. An electric field shielding layer 13 is formed on the outer periphery of the reinforcing insulating layer 12. The electric field shielding layer 13 includes a carbon layer 13a formed by winding crepe carbon paper, and a copper layer 13b made of an annealed copper wire provided on the outer periphery of the carbon layer 13a.

  A shield connection portion 2A in which a superconducting connection portion 20 is joined to the inner peripheral side of the support member 21A is disposed so as to cover the outer periphery of the electric field shielding layer 13. Next, each end of the inner wire 20i and each end of the outer wire 20o are joined to the inner layer 204i and the outer layer 204o of the superconducting shield layer 204 by soldering. This solder is preferably a low melting point solder having a melting point of 70 ° C. or more and 170 ° C. or less in order to reduce thermal deterioration of the electrical insulating layer 203. By joining the superconducting connection part 20 to the superconducting shield layer 204, the support member 21A to which the superconducting connection part 20 is joined is also fixed to the superconducting shield layer 204.

  When the attachment of the shield connection part 2A is finished, the normal conductive connection part 3 is attached to the normal conductive layer 205 of the cable core 101 to connect the normal conductive layers 205 to each other. Here, the terminal 30 is attached to the end of the copper tape constituting the normal conductive layer 205, and the normal conductive connection portion 3 is connected via the terminal 30.

  Through the above steps, the intermediate connection structure 1A for connecting the cable cores 101 of the pair of superconducting cables 100 can be constructed. In addition, the above process is performed for each cable core 101, and the outer periphery of the three intermediate connection structures 1A connecting the three-core cable cores 101 is housed in a connection box (not shown), so that the multi-core cable core 101 is An intermediate connection structure housed in one connection box can be constructed.

  When a connection box having a structure in which half-divided pieces that can be divided in the longitudinal direction are combined and integrated as described in Patent Document 1, assembly work is easily performed. Moreover, if it is set as a cylindrical connection box, the pressure loss by the pressurized refrigerant | coolant distribute | circulated inside the said box can be reduced. In particular, a junction box made of a material having excellent strength such as stainless steel and having a vacuum heat insulating structure is preferable. A connection box having a known configuration can be used. A support member that supports the intermediate connection structure 1A can be disposed in the connection box.

[effect]
The intermediate connection structure 1A having the above configuration mechanically connects a member that connects the superconducting shield layers 204 (shield connecting portion 2A) and a member that connects the normal conducting layers 205 (normal conducting connection portion 3). Since it is not done, it is easy to perform the connection work and the workability is excellent. Moreover, since the rigidity for supporting the superconducting connection portion 20 is not required by making the normal conducting connection portion 3 a separate member independent of the support member 21A, a member having excellent flexibility such as a braided material as described above Can be used for the normal conducting connection part 3, and it is easy to perform the connection work from this point.

  Furthermore, in the intermediate connection structure 1A, since the support member 21A of the shield connection portion 2A is made of copper, the reliability is high even when used under cooling with a refrigerant such as liquid nitrogen. In addition, in the intermediate connection structure 1A, the superconducting connection part 20 is arranged on the inner peripheral side (superconducting conductor side) than the support member 21A made of copper, so that an induced current can easily flow through the superconducting connection part 20, and the superconducting conductor 202 Even when a large current flows through the support member 21A, the shunting of the induced current to the support member 21A can be reduced. Therefore, in the intermediate connection structure 1A, it is possible to reduce the loss due to the shunt (mainly Joule loss) and to secure a sufficiently large induced current (shield current). Therefore, in the intermediate connection structure 1A, the magnetic field due to the current flowing in the superconducting conductor 202 can be canceled out by the magnetic field due to the shield current, and the leakage magnetic field is also small. In particular, when the support member 21A is provided with a slit as described above, it is possible to improve the cooling effect of the connection location existing inside the support member 21A, and to reduce the loss due to the diversion.

  Furthermore, in the intermediate connection structure 1A, the superconducting connection portion 20 and the support member 21A are integrally joined, so that the intermediate connection structure 1A can sufficiently withstand the stress caused by thermal contraction during cable cooling. Therefore, damage to the superconducting connection portion 20 due to this stress can be reduced. In addition, the superconducting connection portion 20 and the support member 21A can be disposed at the same time by being such an integral body. In particular, since the support member 21A is composed of a pair of divided pieces, it can be easily arranged at a predetermined position. Furthermore, the intermediate connection structure 1A includes the normal conductive connection part 3, so that even if the intermediate connection structure 1A is quenched due to an accident or the like, it is possible to flow an accident current using the normal conductive connection part 3. In addition, in the intermediate connection structure 1A, since the support member 21A is not connected to the normal conductive layer 205, the length of the support member 21A in the longitudinal direction is longer than that of the conventional cylindrical member connected to the normal conductive layer. Can be shortened.

<Modification 1>
In the first embodiment, the support member 21A made of a conductive material such as copper has been described, but instead of the conductive material, an insulating material having excellent strength (specific resistance (20 ° C.) is 1.0 × 10 ⁻⁶ Ω · m As described above, preferably 2.0 × 10 ⁻⁶ Ω · m or more), for example, a high-strength resin such as epoxy resin or glass fiber reinforced plastic (GFRP) can be used. Alternatively, it has a large electrical resistance compared to a good conductor such as copper (specific resistance (20 ° C) is 1.7 × 10 ^-8 Ωm), for example, a Cu-Ni alloy (compared to copper). Having an electric resistance of about 10 ³ to 10 ⁴ times). Since the support member is made of an insulating material or a material having a higher resistance than copper, even when a large current flows through the superconducting conductor 202, it is difficult to divert to the support member or it is not substantially diverted. Loss can be reduced, or the loss can be substantially eliminated.

  When the support member is made of an insulating material or a high resistance material, the induced current does not flow substantially (no shunting occurs) or the shunt current is very small. It may be arranged on either the inner peripheral side or the outer peripheral side.

  When joining a superconducting connection to a support member, a metal layer (for example, silver) is formed on the surface of the support member made of epoxy resin, GFRP, or the like by vapor deposition or coating to make it easier to attach solder. It is preferable to keep it.

<Modification 2>
In the first embodiment, the support member 21A made of only a conductive material such as copper has been described. However, the conductive material, the insulating material such as epoxy resin and GFRP described in Modification 1 above, and a high resistance material such as a copper alloy You may comprise a support member combining. For example, the support member 21B shown in FIG. 3 is an assembly that combines a pair of semi-cylindrical divided pieces 210 into a cylindrical shape, and each divided piece 210 is made of copper and epoxy resin. More specifically, each divided piece 210 is formed by joining a pair of cylindrical pieces 211 made of a short semi-cylindrical copper piece by a connecting portion 212 (insulating portion) made of epoxy resin to form an integral divided piece 210. Yes. That is, each divided piece 210 has a shape in which the divided pieces constituting the support member of Embodiment 1 are divided into two in the longitudinal direction and joined by the connecting portion 212.

  The supporting member 21B having the above configuration has one cylindrical piece 211 (a region on one end side of the supporting member 21B) made of copper and the other cylindrical shape made by interposing a connecting portion 212 made of an insulating material. The piece 211 (the region on the other end side) is electrically insulated, and the induced current does not substantially flow between the two cylindrical pieces 211 (no shunting occurs substantially). Therefore, even if the superconducting connection portion is arranged on either the inner peripheral side or the outer peripheral side of the support member 21B, loss due to the above-mentioned diversion cannot occur.

  In support member 21B, most of both divided pieces 210 are made of copper, so that a highly reliable intermediate connection structure can be obtained, and the superconducting connection portion can be easily joined by solder. Further, in the support member 21B, the pair of cylindrical pieces 211 can be easily integrated with the resin constituting the connecting portion 212. The ratio (length in the longitudinal direction) of the connecting portion in the divided pieces can be selected as appropriate. As long as the two cylindrical pieces 211 can be insulated, the length of the connecting portion in the longitudinal direction may be short. Further, in the support member 21B, each divided piece 210 is provided with one connecting portion 212, but a plurality of connecting portions 212 may be provided. Further, the connecting portion 212 may be made of the above-described copper alloy. In this case, the diversion can be reduced as compared with the case where the divided piece is made of only copper.

<Modification 3>
In the first embodiment, the support member 21A having a uniform thickness from one end side to the other end side has been described, but the thickness can be partially changed. That is, the support member can have a thin wall portion. For example, a thin portion provided in an annular shape along the circumferential direction of the support member may be provided between the region on one end side and the region on the other end side of each divided piece constituting the support member. It may have a thin-walled portion provided in Or you may provide the thin part provided in strip | belt shape along the longitudinal direction of a supporting member. When the support member is composed of a good conductor such as copper, like the support member 21A, by providing such a thin portion, it is possible to have a portion having a small cross-sectional area. Loss due to the diversion can be reduced.

(Embodiment 2)
Hereinafter, the intermediate connection structure of the superconducting cable of Embodiment 2 will be described with reference to FIG. The basic configuration of the intermediate connection structure 1C is the same as that of the intermediate connection structure 1A of the first embodiment, and the difference is in the configuration of the shield connection portion 2C. Hereinafter, this difference will be described, and description of other configurations will be omitted.

  Similarly to the shield connection part 2A of the first embodiment, the shield connection part 2C includes a superconducting connection part 20 made of a superconducting wire and a support member 21C made of copper. In particular, in the shield connection portion 2C, the superconducting wire is joined to the outer peripheral surface of the support member 21C by solder.

  The support member 21C has substantially the same shape as the shield connection portion 2A of the first embodiment, and is a combination that is formed into a cylindrical shape by combining a pair of semi-cylindrical divided pieces. And the inner side wire 20i and the outer side wire 20o are laminated | stacked and joined to the outer peripheral surface of each division | segmentation piece. Further, the reinforcing member 22 is joined by solder to a part of the outer peripheral surface of the outer wire 20o, specifically, from the portion disposed along the tapered portion of the support member 21C to the superconducting shield layer 204 of the cable core. And integrated. Examples of the constituent material of the reinforcing material 22 include materials having excellent strength such as a Cu—Ni alloy and stainless steel.

  The inner wire 20i of the superconducting connection portion 20 is joined to the inner layer 204i of the superconducting shield layer 204, and the outer wire 20o is joined to the outer layer 204o. The superconducting connection portion 20 is joined to the superconducting shield layer 204, so that the support member 21C is also fixed to the superconducting shield layer 204.

  The intermediate connection structure 1C having the above configuration is connected to the shield connection part 2C and the normal conductive connection part 3 in a separate member that is not physically connected in the same manner as the intermediate connection structure 1A of the first embodiment. Excellent workability at the time. In addition, since the superconducting connection part 20 and the support member 21C are integrated, it is possible to reduce damage to the superconducting connection part 20 due to stress during thermal contraction of the cable core. In particular, the intermediate connection structure 1C can effectively prevent breakage of the superconducting connection portion 20 by including the reinforcing member 22.

  However, in the intermediate connection portion 1C, the support member 21C is made of a conductive material, so that when a large current is used, a loss due to shunting may occur. Therefore, in the application of high current, as described in the first embodiment, the superconducting connection portion 20 is disposed on the inner peripheral side, the support member is disposed on the outer peripheral side, or at least the support member as described in the first and second modifications. It is preferable that a part is made of a high resistance material, particularly an insulating material.

  The above-described embodiment can be appropriately changed without departing from the gist of the present invention, and is not limited to the above-described configuration.

  The intermediate connection structure of the superconducting cable of the present invention can be suitably used for a connecting portion between the superconducting cables.

1A, 1C intermediate connection structure 2A, 2C shield connection 3 normal conduction connection
10 Connection sleeve 11 Superconducting wire for connection 12 Reinforcing insulation layer 13 Electric field shielding layer
13a Carbon layer 13b Copper layer
20 Superconducting connection 20i Inner wire 20o Outer wire 21A, 21B, 21C Support member
22 Reinforcing material
30 terminals
100 Superconducting cable 101 Cable core 102 Insulated tube 102i Inner tube
102o Outer tube 103 Refrigerant 104 Anticorrosion layer
201 Former 202 Superconducting conductor 203 Electrical insulation layer 204 Superconducting shield layer
204i Inner layer 204o Outer layer 205 Normal conducting layer 206 Protective layer
210 Dividing piece 211 Cylindrical piece 212 Connecting part

Claims (7)

An intermediate connection structure of superconducting cables for connecting a pair of superconducting cables including an electric insulating layer, a superconducting shield layer, and a normal conducting layer in order on the outer periphery of the superconducting conductor,
A superconducting connection portion that is composed of a superconducting material and connects the superconducting shield layers of each superconducting cable;
A normal conducting connection portion that is composed of a normal conducting material and connects the normal conducting layers of each superconducting cable;
An intermediate connection structure for a superconducting cable, comprising: a support member that is not connected to the normal conducting layer and to which the superconducting connecting portion is joined. The support member is made of copper,
2. The intermediate connection structure for a superconducting cable according to claim 1, wherein the superconducting connection portion is joined to a superconducting conductor side of the support member. 2. The intermediate connection structure for a superconducting cable according to claim 1, wherein at least a part of the support member is made of a material having a specific resistance value (20 ° C.) of 1.0 × 10 ⁻⁶ Ω · m or more. . The support member has an insulating portion made of a material having a specific resistance value (20 ° C.) of 1.0 × 10 ⁻⁶ Ω · m or more interposed between a region on one end side and a region on the other end side. 4. The superconducting cable intermediate connection structure according to claim 3, wherein the two regions are electrically insulated by the insulating portion.   5. The intermediate connection structure for a superconducting cable according to claim 1, wherein the support member is a braid that is formed by combining a pair of half-breaking pieces to form a cylindrical body.   6. The intermediate connection of a superconducting cable according to claim 1, wherein the support member is a cylindrical body, and includes an arc-shaped slit provided along a circumferential direction thereof. Construction.   The intermediate connection structure for a superconducting cable according to any one of claims 1 to 6, wherein the support member has a thin portion in which a part of the thickness in the longitudinal direction is thinner than a thickness of the other part.

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