JP2012190654A - Intermediate connection structure of superconducting cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact intermediate connection structure of a superconducting cable in which normal temperature insulation superconducting cables are connected to each other.SOLUTION: The intermediate connection structure of the superconducting cable includes: a connection conductor 1 by which superconductive conductor layers 12 and 12' of the normal temperature insulation superconducting cables 200 and 200' abutted against each other are electrically connected to each other; a multi-tube structural coupling tube 2 by which heat insulation tubes 14 and 14' of the normal temperature insulation superconducting cables 200 and 200' surrounding the outer periphery of the connection conductor 1 and abutted against each other are coupled to each other; and a joint insulating layer 3 which is formed across cable insulating layers 15 and 15' of the normal temperature insulation superconducting cables 200 and 200' surrounding the outer periphery of the coupling tube 2 and abutted against each other.

Description

  The present invention relates to an intermediate connection structure for a superconducting cable formed by connecting a pair of room-temperature insulated superconducting cables.

  In general, a superconducting cable has a configuration in which a conductor portion having a superconducting conductor layer on the outer periphery of a former is housed in a heat insulating tube made of a double metal tube. In such a superconducting cable, there are the following two configurations for electrically insulating the superconducting cable from the outside. The first configuration is a low-temperature insulating configuration in which a cable insulating layer is formed on a superconducting conductor layer, and the cable insulating layer is also cooled by a refrigerant. The second configuration is a room temperature insulation type configuration in which a cable insulation layer is formed on a heat insulating tube and the cable insulation layer is not cooled by a refrigerant (see, for example, specification 0003 of Patent Document 1). In particular, the latter room-temperature insulated superconducting cable is attracting attention because it has the advantage that the insulation material and structure of existing normal conducting cables can be applied.

Japanese Patent Laid-Open No. 08-064041

  When constructing a superconducting cable line by connecting a plurality of room temperature insulated superconducting cables, it is necessary to construct an intermediate connection structure of superconducting cables that connect the superconducting cables together. However, research into the practical application of superconducting cable lines using room-temperature insulated superconducting cables has just begun, and the intermediate connection structure has not been fully studied at present.

  By the way, room-temperature insulated superconducting cables are being laid and installed as an alternative to existing cables in pipelines where existing normal conducting cables are laid. Therefore, it is desired to develop a compact intermediate connection structure when examining an intermediate connection structure formed using a room temperature insulated superconducting cable.

  The present invention has been made in view of the above circumstances, and one of its purposes is a superconducting cable intermediate connection structure for connecting room-temperature insulated superconducting cables to each other, and provides a compact superconducting cable intermediate connection structure There is to do.

  The present invention relates to an intermediate connection structure for superconducting cables formed by connecting a pair of butted superconducting cables. A superconducting cable used for this intermediate connection structure is a room temperature insulation type comprising a superconducting conductor layer, a heat insulation pipe having a multi-tube structure that accommodates the superconducting conductor layer, and a cable insulation layer surrounding the outer circumference of the heat insulation pipe. Superconducting cable. Then, the intermediate connection structure of the superconducting cable of the present invention comprises a connecting conductor for electrically connecting the superconducting conductor layers of the abutted room temperature insulated superconducting cable, and an outer periphery of the connecting conductor, and the abutted room temperature insulated superconducting A multi-pipe structure connecting pipe that connects the heat insulating pipes of the cable, and a connection insulating layer that surrounds the outer periphery of the connecting pipe and straddles both cable insulating layers of the abutted room-temperature insulated superconducting cable It is characterized by.

  According to the intermediate connection structure of the superconducting cable of the present invention, the room-temperature insulated superconducting cables can be connected to each other, so that a superconducting cable line using the room-temperature insulated superconducting cable can be constructed. In addition, the intermediate connection structure of the superconducting cable of the present invention is compactly formed because the heat insulating pipes of the room-temperature insulated superconducting cables that are butted together are directly connected by a connecting pipe. As a result, it is possible to construct a superconducting cable line in an existing pipeline in a limited work space.

  The room temperature insulation type superconducting cable used for the intermediate connection structure of the superconducting cable of the present invention includes a type (hereinafter referred to as CV type) in which a cable insulating layer is formed of an insulating resin, such as a normal conducting CV cable, and a normal conducting type. And a type in which a cable insulating layer is formed by winding an insulating paper (hereinafter referred to as an OF type).

  When the intermediate connection structure of the superconducting cable of the present invention is formed using a CV type room temperature insulated superconducting cable, it is preferable to form a connecting portion insulating layer by combining a previously formed insulating unit and a pair of stress cones. The insulating unit is a member provided with a unit main body having conical insertion holes at both ends and an internal electrode exposed on the inner peripheral surface of the intermediate part of the unit main body. On the other hand, the stress cone is a member having a tapered portion that is fitted into the insertion hole of the insulating unit. In that case, the internal electrode of the insulating unit and the connecting pipe for connecting the heat insulating pipes of the room temperature insulated superconducting cable may be electrically and mechanically connected via a connection fitting.

  An intermediate connection structure can be easily constructed by forming a connection part insulating layer by combining an insulating unit and a stress cone prepared in advance. Further, by using the connection fitting, the insulation unit can be positioned with respect to the connection fitting, that is, the insulation unit can be positioned at an optimum position in the intermediate connection structure. Here, in the room-temperature insulated superconducting cable, since the heat insulating tube has a 100% potential, the connecting tube connected to the heat insulating tube also has a 100% potential. That is, the internal electrode connected to the connecting pipe also has a 100% potential.

  In the prefabricated configuration in which the insulating unit and the stress cone are combined, it is preferable that the connection fitting is fixed to the outer peripheral surface of the connecting pipe.

  By setting it as the said structure, an insulation unit can be firmly fixed with respect to a connection pipe via the connection metal fitting fixed to a connection pipe firmly. In addition, as shown in an embodiment described later, it is possible to easily attach the insulating unit to the connecting pipe by using a connection fitting made of a plurality of arc-shaped protrusions extending in the radial direction of the connecting pipe at the middle portion in the longitudinal direction of the connecting pipe. Can be.

  In the prefabricated configuration, it is preferable to use a pair of pressing hardware that presses the pair of stress cones from both sides.

  By using the pressing metal fitting, it is possible to suppress the formation of a gap between the insulating unit and the stress cone and between the stress cone and the cable insulating layer. Moreover, since the rear end part (the side opposite to the insulating unit) of the stress cone is stopped by the metal fitting, it is possible to suppress the stress cone from being pushed out from the insertion hole of the insulating unit over time. In particular, as shown in an embodiment to be described later, by using a metal fitting using a spring, the force for pressing the stress cone can be maintained substantially constant over a long period of time. As a result, it is possible to suppress a decrease in the insulating properties of the connection portion insulating layer due to a decrease in the pressing force over time.

  On the other hand, when the intermediate connection structure of the superconducting cable of the present invention is formed using an OF type room temperature insulated superconducting cable, the cable insulating layer is impregnated with the insulating paper wound around the outer periphery of the connecting pipe and the insulating paper. And insulating oil.

  Since the insulating structure combining the insulating paper and the insulating oil has excellent insulating characteristics, the insulating characteristic of the intermediate connection structure of the superconducting cable constructed by applying this insulating structure is also excellent.

  According to the intermediate connection structure for superconducting cables of the present invention, room-temperature insulated superconducting cables can be connected in a compact manner.

(A) is a fragmentary longitudinal cross-sectional view of the intermediate connection structure of the room temperature insulation type superconducting cable described in Embodiment 1, and (B) is a partially enlarged view of (A). It is a schematic perspective view of a partial component of the intermediate connection structure. FIG. 2 is an enlarged partial longitudinal sectional view in the vicinity of an insulating unit provided in the intermediate connection structure shown in FIG. 1. FIG. 2 is an enlarged partial longitudinal sectional view in the vicinity of a left pressing metal fitting provided in the intermediate connection structure shown in FIG. 1. FIG. 2 is an enlarged partial longitudinal sectional view in the vicinity of a right pressing metal fitting provided in the intermediate connection structure shown in FIG. 1. It is a schematic cross-sectional view of a typical room temperature insulated superconducting cable.

<Embodiment 1>
Hereinafter, an embodiment of an intermediate connection structure of a superconducting cable of the present invention using a CV type room temperature insulated superconducting cable will be described with reference to the drawings. In the drawings, members having “′” in the reference numerals are members having the same configuration as members having the same reference numerals without “′”.

≪Overall structure≫
The superconducting cable intermediate connection structure 100 shown in FIG. 1 is formed by connecting a pair of room-temperature insulated superconducting cables 200 and 200 ′ that are faced to each other. The intermediate connection structure 100 includes a connection conductor 1, a connecting pipe 2, and a connection part insulating layer 3. The connection conductor 1 is a member that electrically connects the superconducting conductor layers 12 and 12 ′ of the room-temperature insulated superconducting cables 200 and 200 ′ that face each other. The connecting pipe 2 is a multiple pipe that surrounds the outer periphery of the connecting conductor 1 and connects the heat insulating pipes 14 and 14 ′ of the room-temperature insulated superconducting cables 200 and 200 ′ that face each other. The connecting portion insulating layer 3 is an insulating member that surrounds the outer periphery of the connecting pipe 2 and straddles both the cable insulating layers 15 and 15 ′ of the room-temperature insulated superconducting cables 200 and 200 ′ that are faced to each other. The connection part insulating layer 3 in this embodiment is formed by combining the insulating unit 3m and a pair of stress cones 3s and 3s'. The members used for constructing these intermediate connection structures 100 are basically cylindrical members as shown in the schematic perspective view of FIG.

  Hereinafter, each configuration of the intermediate connection structure 100 will be described in detail with reference to FIGS. 1 to 5 as appropriate, while explaining the construction procedure of the intermediate connection structure 100. Prior to the description, a typical configuration of the room temperature insulated superconducting cable 200 (200 ′) will be described with reference to FIG.

≪Room-temperature insulated superconducting cable≫
A room-temperature insulated superconducting cable (hereinafter simply referred to as a superconducting cable) 200 includes a conductor 10, a heat insulating tube 14 that houses the conductor 10 inside, and a cable insulating layer 15 that surrounds the outer periphery of the heat insulating tube 14. .

[Conductor]
The conductor portion 10 typically includes a former 11, a superconducting conductor layer 12 formed on the outer periphery of the former 11, and a protective layer 13. The former 11 is a member used as a support for the superconducting conductor layer 12, and uses, for example, a solid body formed by twisting a plurality of metal wires having an insulating coating such as enamel, or a hollow body such as a metal pipe. Can do. In this embodiment, it was set as the solid body which twisted the covering metal wire.

  Next, as the superconducting conductor layer 12, for example, a tape-like wire material including an oxide superconductor can be suitably used. Examples of the tape-shaped wire include Bi2223 superconducting tape wire (sheath wire in which a filament made of an oxide superconductor is arranged in a stabilizing metal such as Ag-Mn and Ag), RE123 thin film wire (RE: rare earth element, For example, Y, Ho, Nd, Sm, Gd, etc. (Laminated wire material in which an oxide superconducting phase is formed on a metal substrate). The superconducting conductor layer 12 may have a single layer structure or a multilayer structure formed by spirally winding the tape-shaped wire. In this embodiment, the superconducting conductor layer 12 has a multilayer structure.

  The protective layer 13 covers the outer periphery of the superconducting conductor layer 12, protects the superconducting conductor layer 12, and ensures insulation from the heat insulating tube 14. This protective layer 13 can be formed by winding kraft paper or the like.

[Insulated pipe]
The heat insulating tube 14 has a double tube structure including an inner tube 14a that houses the conductor portion 10 therein and an outer tube 14b that houses the inner tube 14a inside. The inner tube 14a is filled with a refrigerant 131 (typically liquid nitrogen, liquid helium, helium gas, etc.) for maintaining the superconducting conductor layer 12 in a superconducting state, and functions as a refrigerant flow path. By forming the heat insulating tube 14 with the inner tube 14a and the outer tube 14b provided on the outer periphery of the inner tube 14a, the temperature of the refrigerant 131 is prevented from rising due to heat entering from the outside. A vacuum is drawn between the inner tube 14a and the outer tube 14b, thereby forming a vacuum heat insulating layer. In addition, if a heat insulating material such as super insulation or a spacer that separates the inner tube 14a and the outer tube 14b is disposed between the inner tube 14a and the outer tube 14b, the heat insulating property of the heat insulating tube 14 can be improved.

  Both the inner tube 14a and the outer tube 14b constituting the heat insulating tube 14 in this embodiment are corrugated tubes. If both the pipes 14a and 14b are corrugated pipes, the heat insulating pipe 14 (that is, the superconducting cable 200) is easily bent, and for example, the superconducting cable 200 is easily introduced into the pipe. Both tubes 14a and 14b may be straight tubes.

[Cable insulation layer]
The cable insulation layer 15 is a layer that electrically insulates the superconducting cable 200 from the external environment. The cable insulation layer 15 can be made of a material having a proven record in normal conducting cables and having excellent electrical insulation strength, typically cross-linked polyethylene (PEX) used for CV cables. If the insulating resin such as cross-linked polyethylene is used, the cable insulating layer 15 can be easily formed simply by extruding the insulating resin to the outer periphery of the heat insulating tube 14.

[Other configurations]
The outer periphery of the cable insulating layer 15 is typically provided with an outer shielding layer made of a normal conductive material such as copper or aluminum. The outer shielding layer provides a potential outside the cable insulation layer 15 and can use a normal conductive material as in the case of a conventional power cable. Further, an anticorrosion layer (not shown) having predetermined insulating properties and protecting the outer shielding layer is provided on the outer periphery of the outer shielding layer.

  In addition, a shunt conductor may be provided between the heat insulating tube 14 and the cable insulating layer 15 to shunt the abnormal current when an abnormal current occurs. The shunt conductor is made of a metal material such as copper, aluminum, or silver having a low electrical resistance value from the viewpoint of sharing a current during an abnormality. In particular, copper is suitable as a shunt conductor in that it has the second highest conductivity after silver and is much cheaper than silver. Such a shunt conductor can be formed by winding a member conforming to the conductor of an existing normal conducting cable, such as a segment conductor formed of a copper stranded wire, on the outer tube 14b.

≪How to build an intermediate connection structure≫
The construction of the intermediate connection structure 100 for connecting the superconducting cables 200 and 200 ′ described above can be performed according to the following steps α to ε (refer to FIGS. 1 to 5 as appropriate).
Step α: The ends of the superconducting cables 200 and 200 ′ that have been stripped are brought into contact with each other, and the superconducting conductor layers 12 and 12 ′ of the superconducting cables 200 and 200 ′ are connected to each other by the connection conductor 1.
Step β: The heat insulating tubes 14 and 14 ′ of the superconducting cables 200 and 200 ′ are connected to each other by the connecting tube 2. The stress cone 3s ′ is arranged at a predetermined position (position when completed in FIG. 1) on the superconducting cable 200 ′.
Step γ: Connects the connecting pipe 2 and the insulating unit 3m.
Step δ: The stress cone 3s is fitted into the left end opening of the insulating unit 3m.
Step ε: The metal fittings 5 and 6 are attached to both ends of the insulating unit 3m, and both stress cones 3s and 3s ′ are pushed inward of the insulating unit 3m.
Step ζ: The end covers 7 and 8 are fitted into the openings on both ends of the insulating unit 3m, and the gaps between the members are sealed.

[Step α]
The ends of the superconducting cable 200 (200 ′) to be connected are the former 11 (11 ′), the superconducting conductor layer 12 (12 ′), the inner tube 14a (14a ′) of the heat insulation tube, and the outer tube 14b (14b ′) of the heat insulation. Steps are stripped so that a part of is exposed in stages. Further, the cable insulation layer 15 (15 ′) is gradually thinned toward the end in a predetermined range near the end of the superconducting cable 200 (200 ′), and is uniform from the predetermined range to the end. It was made to become a diameter. In the “+” hatched portion in the figure, an adhesive semiconductive cross-linked polyethylene tape was wound and a conductive paint was applied. By doing so, the external semiconductive layer of the superconducting cable 200 (200 ′) was made to conduct to a semiconductive rubber portion 38 (38) of a stress cone 3s (3s ′) described later.

  Next, after connecting the formers 11 and 11 ′, the superconducting conductor layers 12 and 12 ′ are connected by the connection conductor 1. The formers 11 and 11 ′ may be connected to each other by inserting the formers 11 and 11 ′ into the opening portions at both ends of the sleeve (not shown) and caulking the sleeves together. On the other hand, the connection between the superconducting conductor layers 12 and 12 'is performed by arranging the connecting conductor 1 so as to straddle the superconducting conductor layer 12 of one superconducting cable 200 and the superconducting conductor layer 12' of the other superconducting cable 200 '. The connection conductor 1 may be connected to both the superconducting conductor layers 12 and 12 'by soldering or the like. The connection conductor 1 is preferably made of the same superconducting wire as the superconducting conductor layers 12 and 12 '.

  In this step α, the cylindrical insulating unit 3m, the stress cone 3s, and the end cover 7 used in the subsequent process are fitted into the superconducting cable 200 and escaped to the left side of the paper, and the end cover 8 is superconducted. It fits into the cable 200 'and escapes to the right side of the page. Further, the stress cone 3 s ′ is arranged at a position where it is arranged when the intermediate connection structure 100 is completed. Here, in the drawing, the difference between the small diameter portion and the large diameter portion of the portion of the cable insulation layers 15 and 15 ′ formed in the pencil down shape seems to be large, but in reality, it is very small (about several mm). . Therefore, the insulating unit 3m and the stress cone 3s can be released to the superconducting cable 200 side.

[Step β]
In step β, the heat insulating tubes 14 and 14 ′ of the superconducting cables 200 and 200 ′ are connected to each other by the connecting tube 2. The connecting tube 2 has a double tube structure composed of a straight tubular inner tube 2a and a straight tubular outer tube 2b. The inner tube 2a can be used as a refrigerant flow path, and the space between the inner tube 2a and the outer tube 2b can be used as a vacuum heat insulating layer. The inner tube 2a (outer tube 2b) can be formed by covering a semi-cylindrical half-cracked structure from the outer peripheral side of the connecting conductor 1 and welding. Further, a super insulation, a spacer, or the like may be disposed between the inner tube 2a and the outer tube 2b, similarly to the heat insulating tubes 14 and 14 '.

  As shown in FIG. 2, a connection fitting 4 is fixedly provided on the outer peripheral surface of the intermediate portion in the longitudinal direction of the connecting tube 2, that is, the outer peripheral surface of the outer tube 2b in the longitudinal direction. The connection fitting 4 illustrated in FIG. 2 is a fan-shaped protrusion that protrudes outward in the radial direction of the outer tube 2b. The connection fitting 4 may be an annular flange-shaped protrusion formed over the entire circumference of the outer tube 2b.

[Process γ]
In step γ, the connecting pipe 2 and the insulating unit 3m are connected. The insulating unit 3m includes a unit main body 30, an internal electrode 31, pedestals 34 and 35, an external cover 36, and an IJ cylinder 39 (see particularly FIG. 2 and FIG. 3).

  The unit main body 30 is a cylindrical body formed of an insulating resin such as epoxy, and has conical insertion holes 30h and 30h ′ at both ends thereof. The inner diameters of the insertion holes 30 h and 30 h ′ are gradually reduced toward the intermediate portion in the longitudinal direction of the unit main body 30.

  The internal electrode 31 is a cylindrical body formed of a conductive member such as copper or aluminum, and is embedded in the unit main body 30. A part of the internal electrode 31 is exposed on the inner peripheral surface of the intermediate part of the unit main body 30, but is not exposed in the conical insertion holes 30h and 30h ′. Further, both end portions in the longitudinal direction of the internal electrode 31 have a rounded shape, and the concentration of the electric field is difficult to occur. On the inner peripheral surface of the internal electrode 31, there is an attachment groove comprising an annular groove formed in the intermediate portion in the longitudinal direction of the internal electrode 31 and a linear slide groove extending from the annular groove toward the superconducting cable 200 ′. 31 g is formed. The mounting groove 31g will be described later.

  The pedestal portion 34 (35) is an annular member provided at the left end portion (right end portion) of the unit main body 30, and serves as a pedestal for attaching the pressing metal 5 (6) and the end cover 7 (8) in a later process. It is a member (see also FIG. 2). The pedestals 34 and 35 are made of metal in consideration of strength.

  The outer cover 36 is an insulating cylindrical member that houses the unit body 30 therein (see also FIG. 2). The external cover 36 can prevent the unit main body 30 from being damaged when the intermediate connection structure 100 is constructed.

  The IJ cylinder 39 is an insulating cylindrical member that is attached to the pedestal portion 35 and is a member that is used for an insulated joint. The IJ cylinder 39 may be attached later.

  In order to connect the insulating unit 3m and the connecting pipe 2 described above, first, the insulating unit 3m that has escaped to the left side of the drawing is moved to the right side of the drawing. At that time, the tip of the connection fitting 4 slides on the slide groove of the attachment groove 31g. When the connection fitting 4 reaches the position of the annular groove of the mounting groove 31g, the insulating unit 3m is rotated so that the tip end portion of the connection fitting 4 is displaced from the slide groove in the circumferential direction. As a result, the position of the insulating unit 3m with respect to the connecting pipe 2 is determined, and the insulating unit 3m is firmly fixed to the connecting pipe 2. At the same time, the stress cone 3s ′ arranged at a predetermined position of the superconducting cable 200 ′ is fitted into the insertion hole 30h ′ of the insulating unit 3m.

[Step δ]
In step δ, the stress cone 3s is fitted into the left end opening of the insulating unit 3m (see particularly FIGS. 2 and 3). Here, annular presser cylinders 32 and 33 are fitted into the insertion holes 30h and 30h ′ of the insulating unit 3m, so that the tips of the stress cones 3s and 3s ′ do not come into contact with the internal electrode 31. Yes. The presser cylinders 32 and 33 are made of an insulating resin.

  The stress cones 3s and 3s ′ fitted into the insulating unit 3m have a shape in which the bottom surfaces of the two truncated cones are bonded to each other (see particularly FIG. 2). The stress cones 3 s and 3 s ′ can be divided into an insulating rubber portion 37 and a semiconductive rubber portion 38, and the boundary surface between the both 37 and 38 is a curved surface so that electric field concentration can be reduced. Yes. Further, the insulating rubber portion 37 has a tapered shape.

[Step ε]
In step ε, the metal fittings 5 and 6 are attached to both ends of the insulating unit 3m, and both the stress cones 3s and 3s ′ are pushed inward of the insulating unit 3m (see particularly FIGS. 2, 4 and 5). By doing so, the taper taper part (tapered part of the insulating rubber part 37) formed in both the stress cones 3s and 3s' and the insertion hole of the insulating unit 3m are in close contact with each other, and substantially between them. Gaps disappear. At the same time, the stress cone 3s (3s ′) and the cable insulating layer 15 (15 ′) of the superconducting cable 200 (200 ′) are in close contact with each other, and there is substantially no gap between them.

  The metal fitting 5 (6) for pushing both the stress cones 3s, 3s 'into the insertion holes 30h, 30h' includes a base part 50 (60), a first bolt 51 (61), a second bolt 52 (62), A pressing cylinder 53 (63) and a spring 5s (6s) are provided.

  The base portion 50 (60) is an annular rigid body, and a plurality of first bolts 51 (61) are attached in the vicinity of the circumferential edge portion. A plurality of second bolts 52 (62) are attached to the inner peripheral side of the base portion 50 (60) with respect to the first bolts 51 (61). Further, a pressing cylinder 53 (63), which is a cylindrical rigid body having a truncated cone surface, is attached to the tip of the second bolt 52 (62). The shape of the pressing cylinder 53 (63) is a shape corresponding to the tapered surface of the stress cone 3s (3s') on the semiconductive rubber portion 38 (38) side. That is, the base part 50 (60) and the pressing cylinder 53 (63) are connected by the second bolt 52 (62). A spring 5s (6s) is provided on the outer periphery of the second bolt 52 (62) between the base portion 50 (60) and the pressing cylinder 53 (63).

  In order to press the stress cone 3s (3s') with the metal fitting 5 (6) having the above configuration, first, the first bolt 51 (61) is screwed into the pedestal portion 34 (35) of the insulating unit 3m, and the insulating unit The metal fitting 5 (6) is fixed to 3 m. Next, the second bolt 52 (62) is rotated, and the second bolt 52 (62) is advanced with respect to the base portion 50 (60). At that time, the pressing cylinder 53 (63) attached to the tip of the second bolt 52 (62) also advances with respect to the base portion 50 (60) fixed to the insulating unit 3m. As a result, the pressing cylinder 53 (63) presses the rear end portion of the stress cone 3s (3s ′), and the stress cone 3s (3s ′) is strongly pressed into the insertion hole 30h (30h ′) of the insulating unit 3m. At this time, due to the action of the spring 5s (6s), the force for pressing the stress cones 3s, 3s ′ by the pressing cylinder 53 (63) becomes substantially constant. Moreover, the pressing force is maintained over a long period of time.

[Step ζ]
In step ζ, the end covers 7 and 8 are fitted from both ends of the insulating unit 3m, and the gaps between the members are sealed. An adhesive insulating tape or the like can be used for sealing the gap. In this fitting, the cable shielding layer provided on the outer periphery of the cable insulation layers 15 and 15 'is also processed.

≪Summary≫
According to the processes α to ζ described above, it is possible to construct the intermediate connection structure 100 of the superconducting cable in which the room temperature insulated superconducting cables 200 and 200 ′ are connected. In addition, since the constructed intermediate connection structure 100 is compact in the radial direction of the superconducting cables 200 and 200 ′, it can be formed with a margin even in a narrow work space such as an existing pipe line.

<Embodiment 2>
In the first embodiment, the intermediate connection structure of the superconducting cable for connecting the CV type room temperature insulated superconducting cable has been described, but the superconducting cable to be connected may be of the OF type. In that case, in the construction of the intermediate connection structure, first, as in the construction of the CV type intermediate connection structure, as shown in FIG. 3, the formers 11, 11 ′, the superconducting conductor layers 12, 12 ′, the heat insulating tubes 14, 14 ′. Connect each other. In that case, the connection pipe 2 in which the connection metal fitting 4 is not provided is utilized for the connection pipe 2 utilized for connection of the heat insulation pipes 14 and 14 '.

  Next, the insulating paper is wound on the outer peripheral surface of the connecting pipe 2, and the insulating paper is impregnated with insulating oil after covering the outer periphery of the wound insulating paper. Semi-synthetic paper such as kraft tape or PPLP (registered trademark of Sumitomo Electric Industries, Ltd.) can be used as the insulating paper. The insulating oil can be a synthetic oil such as polybutene oil. Here, since the connecting pipe 2 is a straight pipe, it is easy to wind the insulating paper, and a gap is formed between the connecting pipe 2 and the insulating paper or between the turns of the insulating paper as an electrical weak point. hard.

  Also by the structure of Embodiment 2 demonstrated above, since the connection pipe which connects heat insulation pipes is comprised from the several straight pipe | tube, the enlargement of an intermediate connection structure can be suppressed.

  In addition, this invention is not necessarily limited to embodiment mentioned above, In the range which does not deviate from the summary of this invention, it can change suitably. For example, in forming the CV type intermediate connection structure, the connection part insulating layer may be formed by resin molding on the outer periphery of the connecting pipe on site.

  The intermediate connection structure of the superconducting cable of the present invention can be suitably used for forming a large current transmission network using a room temperature insulated superconducting cable.

DESCRIPTION OF SYMBOLS 100 Intermediate connection structure 200,200 'Room temperature insulation type superconducting cable 10 Conductor part 11,11' Former 12,12 'Superconducting conductor layer 13,13' Protective layer 14,14 'Heat insulation pipe 14a, 14a' Inner pipe 14b, 14b ' Outer tube 15, 15 'Cable insulation layer 131 Refrigerant 1 Connection conductor 2 Connection tube 2a Inner tube 2b Outer tube 3 Connection portion insulation layer 3m Insulation unit 30 Unit body 30h, 30h' Insert hole 31 Internal electrode 31g Mounting groove 32, 33 Presser Tube 34, 35 Pedestal portion 36 External cover 39 IJ tube 3s, 3s' Stress cone 37 Insulating rubber portion 38 Semi-conductive rubber portion 4 Connection fitting 5, 6 Press fitting 50, 60 Base portion 51, 61 First bolt 52, 62 First Two bolts 53, 63 Press cylinder 5s, 6s Spring 7, 8 End cover

Claims (5)

An intermediate connection structure of superconducting cables formed by connecting a pair of butted superconducting cables,
The superconducting cable is a room temperature insulation type superconducting cable comprising a superconducting conductor layer, a heat insulating tube having a multi-tube structure that accommodates the superconducting conductor layer therein, and a cable insulating layer surrounding the outer periphery of the heat insulating tube.
A connecting conductor that electrically connects the superconducting conductor layers of the room-temperature insulated superconducting cables that are abutted together;
A connecting pipe of a multi-tube structure that surrounds the outer periphery of the connecting conductor and connects the heat insulating pipes of the abutted room temperature insulation type superconducting cable,
A connecting portion insulating layer that surrounds the outer periphery of the connecting pipe and straddles both cable insulating layers of the abutted room-temperature insulated superconducting cable; and
An intermediate connection structure for a superconducting cable, comprising: The connection part insulating layer is
An insulating unit comprising: a unit main body having conical insertion holes at both ends; and an internal electrode exposed on the inner peripheral surface of the intermediate part of the unit main body;
A pair of stress cones having a tapered portion to be fitted into the insertion hole;
With
The intermediate connection structure for a superconducting cable according to claim 1, further comprising a connection fitting for electrically and mechanically connecting the internal electrode and the connecting pipe.   The superconducting cable intermediate connection structure according to claim 2, wherein the connection fitting is fixed to an outer peripheral surface of the connecting pipe.   The intermediate connection structure for a superconducting cable according to claim 2 or 3, further comprising a pair of pressing metal fittings for pressing the pair of stress cones from both sides. The cable insulation layer is
Insulating paper wound around the outer periphery of the connecting pipe;
Insulating oil impregnated in the insulating paper;
The intermediate connection structure of a superconducting cable according to claim 1, comprising:

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