Cable connection structure, linked power cable, and method for manufacturing a cable connection structure

Abstract

To achieve stable insulation in the cable connection structure. [Solution] The cable connection structure comprises a power cable having a conductor, a cable insulation layer, and a cable metal shielding layer in that order from the central axis of the conductor outward; a grounding wire arranged along the power cable and grounded to the outside; a shielding connection part connecting the cable metal shielding layer of the power cable and the grounding wire; and a filling part that has insulating properties and fills the area between the grounding wire and the power cable at a position close to the shielding connection part.

Description

Technical Field

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[0001] The present disclosure relates to a cable connection structure, a connecting power cable, and a method for manufacturing the cable connection structure.

Background Art

[0002] As a cable connection structure for connecting a pair of power cables, various structures have been disclosed (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present disclosure is to obtain stable insulation of a cable connection structure.

Means for Solving the Problems

[0005] According to one aspect of the present disclosure, there is provided a cable connection structure including: a power cable having a conductor, a cable insulation layer, and a cable metal shielding layer in this order from the central axis of the conductor toward the outer periphery; a ground wire disposed along the power cable and grounded to the outside; a shielding connection portion connecting the cable metal shielding layer of the power cable and the ground wire; and a filling portion having an insulating property and filling a region between the ground wire and the power cable at a position close to the shielding connection portion.

Effects of the Invention

[0006] According to the present disclosure, stable insulation of a cable connection structure can be obtained.

Brief Description of the Drawings

[0007] [Figure 1] Figure 1 is a schematic cross-sectional view showing a power cable. [Figure 2] Figure 2 is a schematic cross-sectional view along the axial direction of a conductor showing a cable connection structure according to one embodiment of the present disclosure. [Figure 3] Figure 3 is an enlarged schematic perspective view of a part of a cable connection structure according to one embodiment of the present disclosure. [Figure 4] Figure 4 is an enlarged schematic cross-sectional view of a part of a cable connection structure according to one embodiment of the present disclosure. [Figure 5] Figure 5 is a schematic, enlarged view of a portion of a cable connection structure according to one embodiment of the present disclosure. [Figure 6A] Figure 6A is a schematic perspective view showing a spacer according to one embodiment of the present disclosure. [Figure 6B] Figure 6B is a schematic perspective view showing a spacer according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0008] [Description of Embodiments in this Disclosure] <Insights gained by the inventor> First, let me explain the findings of the inventor.

[0009] Cable connection structures may include a grounding wire that is connected to the outside. Such a grounding wire needs to be connected to the wire shield of the cable metal shielding layer in each pair of power cables. Hereinafter, the connection point between the grounding wire and the cable metal shielding layer will also be referred to as the "shielding connection point".

[0010] Regarding the cable connection structure equipped with the shielded connection part described above, the inventors found that the following new problems arise as a result of their investigation.

[0011] Conventionally, at a position close to the shielding connection part, a gap may be formed between the ground wire and the power cable. Only air existed in the gap without any other members being provided. The dielectric strength (dielectric breakdown strength, withstand voltage) of the air in the gap was low. Therefore, when an impulse voltage was applied to the cable connection structure and the voltage applied to the gap became equal to or higher than the dielectric strength of the air in the gap, a conductive path was formed from the high-voltage shielding connection part through the gap to the ground (for example, the metal water shielding layer of the water-repellent heat shrinkable tube layer). As a result, there was a risk of an unintentional ground fault current flowing through the conductive path.

[0012] As described above, in the conventional cable connection structure, the insulation of the cable connection structure may become unstable. Therefore, a cable connection structure capable of obtaining stable insulation has been desired.

[0013] The following disclosure is based on the above findings discovered by the present disclosure's inventors.

[0014] <Embodiments of the Present Disclosure> Next, embodiments of the present disclosure will be listed and described.

[0015] [1] A cable connection structure according to an aspect of the present disclosure is a cable connection structure, a power cable having a conductor, a cable insulation layer, and a cable metal shielding layer in this order from the central axis of the conductor toward the outer periphery, a ground wire arranged along the power cable and grounded to the outside, [[ID=二十六]]a shielding connection part connecting the cable metal shielding layer and the ground wire of the power cable, a filling part having insulation and filling a region between the ground wire and the power cable at a position close to the shielding connection part, and includes. According to this configuration, stable insulation of the cable connection structure can be obtained.

[0016] [2] In the cable connection structure described in [1] above, A pair of the power cables are provided, The cable connection structure is, a cylindrical sleeve that connects the conductors of the pair of power cables, a cylindrical insulating unit that is provided to cover the outer periphery of the region including the sleeve and maintains the insulation around the sleeve, a spacer that surrounds the outer periphery of each of the pair of power cables and is provided to contact the axial end of the insulating unit, and gradually decreases in diameter in a direction away from the end of the insulating unit along the conductor, and is provided with, The shielding connection part is fixed to the spacer. According to this configuration, even if a spacer is provided, formation of a gap can be prevented.

[0017] [3] In the cable connection structure according to [2] above, [[ID=2l]]The spacer is configured as a molded body. According to this configuration, it is possible to improve the structural stability in the vicinity of the shielding connection part.

[0018] [4] In the cable connection structure according to [2] or [3] above, The shielding connection part includes a metal, and has a current collecting plate to which a terminal connected to an end of the cable metal shielding layer and a terminal connected to an end of the ground wire are connected, The current collecting plate is fixed to the spacer. According to this configuration, it is possible to improve the structural stability in the vicinity of the shielding connection part.

[0019] [5] The connected power cable according to another aspect of the present disclosure is, provided with at least one cable connection structure according to any one of [1] to [3] above. According to this configuration, stable insulation can be obtained.

[0020] [6] A method for manufacturing a cable connection structure according to another aspect of the present disclosure is, A step of preparing a power cable having a conductor, a cable insulation layer, and a cable metal shielding layer in this order from the central axis of the conductor outwards, A step of connecting a grounding wire, which is arranged along the power cable and grounded to the outside, and the cable metal shielding layer of the power cable, by a shielding connection part, Equipped with, In the process of connecting using the aforementioned shielding connection part, The area between the grounding wire and the power cable near the shielding connection is filled with an insulating filler. This configuration allows for stable insulation of the cable connection structure.

[0021] [Details of the embodiments of this disclosure] Next, an embodiment of the present disclosure will be described below with reference to the drawings. However, the present disclosure is not limited to these examples, and is intended to include all modifications within the meaning and scope of the equivalents of the claims.

[0022] <One Embodiment of the Present Disclosure> (1) Schematic configuration of linked power cables and cable connection structure The schematic configuration of a connected power cable 10 and a cable connection structure (cable connection part) 20 according to one embodiment of this disclosure will be described with reference to Figures 1 to 6B.

[0023] In Figures 2, 4, and 5, the lower half of the cable connection structure 20 is omitted. In Figures 2, 4, and 5, the power cable 100, grounding wire 190, and bolt 654, which have been peeled off in stages, are shown from the side. In Figures 2, 4, and 5, some hatching has been omitted. Figure 3 shows the protective section 400 with the inner protective layer 430, water-insulating heat-shrinkable tube layer 450, filling section 720, insulating tape layer 740, and grounding wire protective layer 760 peeled off.

[0024] In the following, "axial direction" of the power cable 100 refers to the direction along the central axis of the power cable 100, and can be rephrased as the longitudinal direction of the power cable 100. "Radial direction" of the power cable 100 refers to the direction perpendicular to the axial direction of the power cable 100, and can be rephrased as the short direction of the power cable 100 in some cases. The same terminology as for the power cable 100 is used for other cylindrical and columnar members that constitute the cable connection structure 20. "Suppression" of a predetermined phenomenon means preventing the occurrence of the predetermined phenomenon or making it difficult for the predetermined phenomenon to occur.

[0025] As shown in Figure 2, the connected power cable 10 of this embodiment includes, for example, a plurality of power cables 100 and at least one cable connection structure 20.

[0026] (First power cable and second power cable) As shown in Figure 1, the power cable 100 is configured as a solid-insulated cable, which is a high-voltage power transmission cable on land or underground. The power cable 100 is configured as, for example, a CV cable (also known as a cross-linked polyethylene insulated vinyl sheath cable, or XLPE cable).

[0027] Specifically, the power cable 100 has, for example, a conductor 110, an internal semiconducting layer 120, a cable insulation layer 130, an external semiconducting layer 140, a water-absorbing layer (not shown), a cable metal shielding layer 150, and a cable sheath 160, arranged in this order from the central axis of the conductor 110 outwards.

[0028] The conductor 110 has, for example, a plurality of conducting strands (not shown in the diagram). The conducting strands include, for example, at least one of copper and aluminum.

[0029] The cable insulation layer 130 contains a polyolefin such as polyethylene. The polyolefin may be crosslinked.

[0030] The cable metal shielding layer 150 has, for example, a plurality of wire shields (hereinafter sometimes referred to as wire shields 152 in relation to Figure 3) containing copper. The cable metal shielding layer 150 is formed by winding the plurality of wire shields 152 around the outer surface of the inner layer.

[0031] As shown in Figure 2, the power cable 100 is stripped in stages from the axial end of the conductor 110 toward the opposite side (so-called "step stripping"). That is, the conductor 110, the internal semiconducting layer 120, the cable insulation layer 130, the external semiconducting layer 140, the cable metal shielding layer 150, and the cable sheath 160 are exposed in this order from the axial end of the conductor 110 toward the opposite side. Hereafter, each part that is stripped in stages and exposed may be referred to as the "exposed part". With this configuration, power cables 100 can be connected to each other sequentially from the region close to the central axis toward the outer circumference.

[0032] As shown in Figure 2, multiple power cables 100 are provided. Of the multiple power cables 100, a pair of power cables 100 are butted together with the axes of their conductors 110 aligned. Hereinafter, one of the pair of power cables 100 will be referred to as the "first power cable 100a," and the other power cable 100 will be referred to as the "second power cable 100b."

[0033] (Cable connection structure) As shown in Figure 2, the cable connection structure 20 is configured to connect a pair of power cables 100 as a so-called insulating connection in a three-phase AC system, for example. Specifically, the cable connection structure 20 includes, for example, the pair of power cables 100 described above, a sleeve (conductor connecting tube) 200, an insulating unit (insulating tube, rubber connecting tube, rubber unit) 300, a spacer 500, a grounding wire 190, a shielding connection part 600, and a protective part 400.

[0034] (sleeve) The sleeve 200 is configured, for example, as a cylindrical metal tube, and is provided to connect the conductors 110 of a pair of power cables 100 and to surround the ends of each of the conductors 110. The cylindrical sleeve 200 may have a partition wall (not shown) in the center of the hollow portion.

[0035] For example, a semiconducting tape may be wrapped around the cable insulation layer 130 to fill the space between the pair of cable insulation layers 130. This can suppress uneven surface pressure of the insulation unit 300.

[0036] (Insulation unit) The insulating unit 300 is configured, for example, as an insulating cylindrical member and is provided to cover the outer circumference of the area including the sleeve 200.

[0037] The insulating unit 300 is configured, for example, as a so-called room-temperature shrinkable type or a factory-expandable type. That is, the insulating unit 300 has an elastic material that is integrally molded and is designed to shrink elastically at room temperature to closely adhere to the connection portion of the power cable 100.

[0038] The insulating unit 300 is configured, for example, to maintain insulation around the sleeve 200 while mitigating the electric field around the sleeve 200. Specifically, the insulating unit 300 includes, for example, an internal semiconducting layer 320, an insulating unit insulating layer 340, and an external semiconducting layer 380.

[0039] The internal semiconducting layer 320 is configured in a cylindrical shape to cover the outer circumference of the sleeve 200. The internal semiconducting layer 320 contains, for example, semiconducting rubber. The internal semiconducting layer 320 is at the same potential as the sleeve 200.

[0040] The insulating unit insulating layer 340 is provided to cover the outer periphery of the internal semiconducting layer 320, a portion of the first power cable 100a, and a portion of the second power cable 100b. The insulating unit insulating layer 340 includes, for example, insulating rubber.

[0041] The external semiconducting layer 380 is provided in the area outside the insulating unit 300 and is provided so as to cover the outer circumference of the insulating unit insulating layer 340, a portion of the first power cable 100a, and a portion of the second power cable 100b. The external semiconducting layer 380 contains semiconducting rubber.

[0042] The outer semiconducting layer 380 has, for example, a stress cone portion 360. The stress cone portion 360 is provided near both axial ends of the insulating unit insulating layer 340. The stress cone portion 360 has a cone-shaped inner surface that widens toward the axial center of the insulating unit insulating layer 340. A portion of the inner surface of the stress cone portion 360 is in contact with the exposed portion of the cable outer semiconducting layer 140 of the stripped power cable 100.

[0043] This configuration of the insulating unit 300 allows for electrical shielding around the sleeve 200 while mitigating the electric field at the tip of the cable's outer semiconducting layer 140.

[0044] In this embodiment, the outer semiconducting layer 380 has at least one isolation section SP separated in the axial direction of the first power cable 100a and the second power cable 100b. Here, the isolation section SP is provided, for example, at a position close to the second power cable 100b. The isolation section SP separates, for example, a region close to the first power cable 100a from a region close to the second power cable 100b. This allows the insulating unit 300 to be electrically isolated between the shielding of the first power cable 100a and the shielding of the second power cable 100b.

[0045] In this embodiment, the first axial end of the insulating unit 300 is provided with a first end face 390a perpendicular to the central axis of the insulating unit 300. On the other hand, the second end opposite the first axial end of the insulating unit 300 is provided with a second end face 390b perpendicular to the central axis of the insulating unit 300. The vertical first end face 390a and second end face 390b of the insulating unit 300 are used, for example, as support surfaces when an enlarged diameter pipe for passing a power cable 100 is hydraulically inserted into the hollow portion of the insulating unit 300.

[0046] (Spacer) The spacers 500 are provided, for example, near the first and second axial ends of the insulating unit 300, forming a smooth slope.

[0047] (ground wire) The grounding wire 190 is arranged along the power cable 100, for example, outside the insulating unit 300. The grounding wire 190 is configured, for example, to be grounded to the outside. The grounding wire 190 is configured, for example, as an IV wire (vinyl insulated wire, indoor PVC wire). Alternatively, the grounding wire 190 may be configured, for example, as a copper core wire cable (XLPE cable).

[0048] For example, a pair of grounding wires 190 are provided. Each pair of grounding wires 190 is arranged along a pair of power cables 100. Each of the pair of grounding wires 190 is connected to the shielding of other phases in an adjacent section for so-called cross-bonded grounding.

[0049] (Shielded connection section) The shielding connection section 600 is, for example, located outside the insulating unit 300 and is configured to connect the respective cable metal shielding layers 150 of the pair of power cables 100 to the aforementioned grounding wire 190.

[0050] (Protection Department) The protective section 400 is provided so as to cover the outer circumference of the insulating unit 300, the outer circumference of the spacer 500, the outside of the shielding connection section 600, the outer circumference of the grounding wire 190, and a portion of the outer circumference of each of the pair of power cables 100, and is configured to protect the outside of these components.

[0051] (2) Filling section As shown in Figures 2, 4, and 5, the cable connection structure 20 of this embodiment has, for example, a filling portion 720.

[0052] The filling portion 720 is provided, for example, near the shielding connection portion 600, to fill (fill) the area between the grounding wire 190 and the power cable 100. This prevents the formation of air-filled gaps between the grounding wire 190 and the power cable 100.

[0053] The filling portion 720 has, for example, insulating properties. Specifically, the insulating strength (dielectric breakdown strength, dielectric breakdown voltage) of the material constituting the filling portion 720 is higher than that of air. This makes it possible to stably suppress the formation of conductive paths in the region between the grounding wire 190 and the power cable 100.

[0054] The filling section 720 has, for example, moisture-proof properties. This makes it possible to suppress the propagation (water runoff) of water that has entered the cable connection structure 20.

[0055] Specifically, the filling section 720 includes, for example, putty tape. The putty tape has, for example, an insulating putty layer and an adhesive layer that adheres the putty layer to the object. The material of the putty layer can be, for example, polyisobutylene. The filling section 720 is formed by wrapping the putty tape multiple times around the outer circumference of the power cable 100. The laminated structure of the putty tape in the filling section 720 will remain even after the cable connection structure 20 has been manufactured.

[0056] The filling portion 720 is provided, for example, from the shielding connection portion 600 along the grounding wire 190 and the power cable 100 for a predetermined length. The length of the filling portion 720 in the axial direction of the power cable 100 is not limited as long as the formation of a gap between the grounding wire 190 and the power cable 100 can be prevented.

[0057] However, in this embodiment, the filling portion 720 may be provided, for example, to cover the entire exposed portion of the cable metal shielding layer 150 of the power cable 100. This prevents the formation of a conductive path from the shielding connection portion 600 through the cable metal shielding layer 150 to the external ground.

[0058] The filling sections 720 are provided in pairs, for example. The pair of filling sections 720 are provided on the outer circumference of the first power cable 100a and the outer circumference of the second power cable 100b, respectively. Hereinafter, the filling section 720 that fills the area between the first power cable 100a and the grounding wire 190 will also be referred to as the "first filling section 720a," and the filling section 720 that fills the area between the second power cable 100b and the grounding wire 190 will also be referred to as the "second filling section 720b."

[0059] (3) Other configurations outside the insulating unit Next, with reference to Figures 2 to 6B, the details of the other configurations outside the insulating unit 300 of the cable connection structure 20 in this embodiment will be described.

[0060] (3-1) Spacer As shown in Figures 2 to 6B, the spacer 500 is provided, for example, to surround the outer circumference of each of the pair of power cables 100 and to be in contact with the axial end of the insulation unit 300. The spacer 500 gradually decreases in diameter, for example, in the direction away from the axial end of the insulation unit 300 along the conductor 110. This makes it possible to form a gently sloping slope (inclined surface, conical surface) from the outer circumference of the insulation unit 300 toward the outer circumference of the power cable 100.

[0061] Hereinafter, the spacer 500 surrounding the outer circumference of the first power cable 100a will be referred to as the "first spacer 500a," and the spacer 500 surrounding the outer circumference of the second power cable 100b will be referred to as the "second spacer 500b."

[0062] In this embodiment, the spacer 500 is made of, for example, a molded body. This makes it easy to form a slope near the axial end of the insulating unit 300.

[0063] In this embodiment, the spacer 500 includes, for example, a thermoplastic resin. This allows the spacer 500 to be easily molded. The spacer 500 may, for example, be insulating, semiconductive, or conductive. Examples of thermoplastic resins for the spacer 500 include nylon, polycarbonate, and phenolic resin. In particular, nylon has the rigidity, heat resistance, and electrical properties required for the spacer 500, and is easy to mold freely.

[0064] In this embodiment, the spacer 500 has, for example, a hollow structure. This makes it possible to suppress shrinkage of the resin during mold molding. The novel problem of this disclosure is the formation of a conductive path from the shielding connection portion 600 on the spacer 500 to the ground (for example, the metal waterproofing layer of the waterproofing heat shrinkable tubing layer) through the void. For this reason, voids in the spacer 500 located in areas closer to the power cable 100 are not a problem in this disclosure.

[0065] In this embodiment, the spacer 500 is divided into, for example, multiple sections. The spacer 500 includes at least a first section 512 and a second section 514. The first section 512 and the second section 514 are divided in a cross-section that includes a central axis CA. This allows the first section 512 and the second section 514 to be fitted from outside the outer circumference of the power cable 100.

[0066] In this embodiment, as shown in Figures 2 to 6B, the spacer 500 has, for example, a conical portion 520, a cylindrical portion 540, and a gripping portion 560.

[0067] The conical portion 520 is, for example, conical in shape and gradually decreases in diameter in the axial direction of the spacer 500. The enlarged end of the conical portion 520 is positioned to contact the axial end of the insulating unit 300.

[0068] The cylindrical portion 540 is, for example, cylindrical in shape, connected to the reduced diameter end of the conical portion 520, and extends with a constant diameter in the direction away from the conical portion 520.

[0069] The gripping portion 560 is provided, for example, opposite the conical portion 520, sandwiching the cylindrical portion 540, and is configured to grip the outer circumference of the power cable 100. Specifically, the gripping portion 560 is further reduced in diameter from the cylindrical portion 540. The reduced-diameter end of the gripping portion 560 is in contact with the outer circumference of the semiconductive tape layer 480, described later, which covers the exposed portion of the cable's outer semiconductive layer 140.

[0070] As described above, the two-stage structure of the spacer 500 makes it possible to reduce the volume of the air layer formed within the hollow portion of the spacer 500. This suppresses heat buildup within the hollow portion of the spacer 500.

[0071] In this embodiment, each of the conical portion 520, the cylindrical portion 540, and the gripping portion 560 has, for example, a rib 580.

[0072] The rib 580 is, for example, plate-shaped and is provided radially from the inner circumferential surfaces of the conical portion 520, the cylindrical portion 540, and the gripping portion 560 toward the central axis CA. The rib 580 extends, for example, across the conical portion 520, the cylindrical portion 540, and the gripping portion 560. As a result, even if stress (shrinkage force, tightening force) from the inner protective layer 430 and the water-impermeable heat-shrinkable tube layer 450 is applied to the spacer 500 during the protective portion forming step S60 described later, the rib 580 can maintain the shape of the spacer 500.

[0073] In this embodiment, for example, multiple ribs 580 are provided. Specifically, the ribs 580 are provided, for example, in positions that are four times symmetrical around the central axis CA of the spacer 500. The first division portion 512 and the second division portion 514 have ribs 580 at positions that are in contact with each other, and are configured to engage via the ribs 580. As a result, even if you release your hand from the spacer 500, the spacer 500 can be held on the outer circumference of the power cable 100 with the first division portion 512 and the second division portion 514 connected. In other words, it becomes possible to easily attach the spacer 500.

[0074] (3-2) Shielded connection section As shown in Figures 2 to 5, at the shielding connection section 600 of the cable connection structure 20, the wire shield 152 of the cable metal shielding layer 150 of a pair of power cables 100 is connected to the grounding wire 190 which is grounded to the outside.

[0075] In this embodiment, the shielding connection portion 600 is fixed to, for example, a spacer 500. This stabilizes the structure near the shielding connection portion 600. As a result, stable insulation of the cable connection structure 20 can be obtained.

[0076] Specifically, the shielding connection portion 600 of this embodiment includes, for example, a current collector plate 620 and a band 660.

[0077] The current collector plate 620 contains metal. Examples of metals for the current collector plate 620 include copper and aluminum.

[0078] The current collector plate 620 is connected to terminals 642, which are connected to the ends of the cable metal shielding layer 150 (of the multiple wire shields 152), and to terminals 644, which are connected to the ends of the grounding wire 190. Terminals 642 and 644 are fastened to the current collector plate 620 by bolts 652 and 654, respectively.

[0079] In this embodiment, the current collector plate 620 has a shape that follows the outer circumferential surface of the spacer 500 (a shape close to the outer circumferential surface). Specifically, when viewed in the creepage direction, the current collector plate 620 has a polygonal or semicircular shape. This allows the current collector plate 620 to be stably close to (in contact with) the spacer 500 along its outer circumferential surface. Here, the current collector plate 620 has a shape that is, for example, a half-octagon. Because the current collector plate 620 has a polygonal cross-sectional shape in this way, the terminals 642 and 644 can be stably connected to the flat surface of the current collector plate 620.

[0080] The current collector plate 620 is fixed to the spacer 500. This improves the structural stability near the shielding connection 600.

[0081] Specifically, the current collector plate 620 is, for example, placed on the outer circumferential surface of the spacer 500. In other words, the current collector plate 620 is in contact with the outer circumferential surface of the spacer 500 in the radial direction of the conductor 110.

[0082] Furthermore, the current collector plate 620 has holes (not shown) near both ends in the longitudinal direction through which the band 660 is inserted, and is fixed to the spacer 500 by the band 660.

[0083] The band 660 is configured, for example, as a strip-shaped or string-shaped member that fastens the current collector plate 620 to the outer circumferential surface of the spacer 500. Examples of materials for the band 660 include resin materials such as nylon, and metal materials such as stainless steel or copper. The band 660 may also be, for example, an Insulok® (registered trademark). By using such a band 660, the current collector plate 620 can be stably fixed to the spacer 500.

[0084] In this embodiment, the current collector plate 620 is fixed, for example, to the cylindrical portion 540 of the spacer 500. This allows the current collector plate 620 to be easily and stably tightened against the cylindrical portion 540 by the band 660. By tightening the band 660 against the cylindrical portion 540, which does not have an inclination, the tightening force of the band 660 can suppress displacement of the current collector plate 620.

[0085] In this embodiment, the wire shield 152 of the cable metal shielding layer 150 described above is connected to the current collector plate 620 with, for example, its tip facing the tip of the conductor 110 and in a slack state relative to the axial direction of the conductor 110. By not bending the wire shield 152 away from the axial tip of the conductor 110 (at an angle close to 180°), damage to the exposed portion of the cable's outer semiconducting layer 140 caused by bending the wire shield 152 can be suppressed. Furthermore, by connecting the wire shield 152 to the current collector plate 620 in a slack state, displacement of the current collector plate 620 can be suppressed even if a pulling force is applied to the wire shield 152 toward the cable sheath 160.

[0086] In this embodiment, the area of ​​the current collector plate 620 perpendicular to the direction from the connection point of the grounding wire 190 to the connection point of the cable metal shielding layer 150 (= width in the short direction of the current collector plate 620 × thickness) is, for example, greater than or equal to the total area of ​​the cross-sections perpendicular to the axial direction of the multiple wire shields 152 included in the cable metal shielding layer 150. This makes it possible to suppress the current collector plate 620 from having high resistance compared to the cable metal shielding layer 150. As a result, stable conductivity through the current collector plate 620 between the cable metal shielding layer 150 and the grounding wire 190 can be ensured.

[0087] (3-3) Shielding structure As shown in Figures 2, 4, and 5, the cable connection structure 20 further includes, for example, a semiconducting tape layer 480, a first shielding layer 410 (thick dotted line), and a second shielding layer 420 (thick dotted line) as an electrical shielding structure.

[0088] (Semiconductive tape layer) The semiconductive tape layer 480 is formed, for example, by wrapping semiconductive tape around the outer circumference of the exposed portion of the cable's outer semiconductive layer 140 between the spacer 500 and the power cable 100.

[0089] (1st shielding layer) As shown in Figures 2 and 4, in this embodiment, the first shielding layer 410 is provided to continuously cover, for example, the outer circumference of the exposed portion of the cable outer semiconductive layer 140 of the first power cable 100a, the outer circumference of the spacer 500, and the outer circumference of the outer semiconductive layer 380 of the insulating unit 300. The first shielding layer 410 is made of, for example, copper mesh tape. The first shielding layer 410 electrically shields the area close to the first power cable 100a and ensures a secure connection between the cable metal shielding layer 150 of the first power cable 100a and the outer semiconductive layer 380 of the insulating unit 300.

[0090] (2nd shielding layer) As shown in Figures 2 and 5, in this embodiment, the second shielding layer 420 is provided, for example, between the spacer 500 and the second power cable 100b so as to cover the outer circumference of the exposed portion of the cable outer semiconducting layer 140 of the second power cable 100b, and is connected to the stress cone portion 360 of the insulating unit 300. The second shielding layer 420 is provided, for example, on the outer circumference of the semiconducting tape layer 480. The second shielding layer 420 is made of copper mesh tape, for example, similar to the first shielding layer 410. The second shielding layer 420 electrically shields the area close to the second power cable 100b and ensures a reliable connection between the cable metal shielding layer 150 of the second power cable 100b and the stress cone portion 360 of the insulating unit 300.

[0091] (3-4) Protection part As shown in Figures 2, 4, and 5, in this embodiment, the protective section 400 that protects the outside of the insulating unit 300, spacer 500, shielding connection section 600, grounding wire 190, and pair of power cables 100 is composed of multiple layers, for example. Specifically, the protective section 400 includes, for example, an insulating tape layer 740, a grounding wire protection layer 760, an inner protective layer 430, and a water-resistant heat-shrinkable tube layer 450.

[0092] (Insulating tape layer) The insulating tape layer 740 is, for example, insulating and is provided to cover the outside of the shielding connection portion 600. This makes it possible to maintain the insulating properties around the shielding connection portion 600.

[0093] Specifically, the insulating tape layer 740 is provided to continuously cover the outer periphery of the area including the bolts 652 and 654 that fasten terminals 642 and 644 to the current collector plate 620. The insulating tape layer 740 is provided, for example, by having an insulating self-fusing tape and wrapping the self-fusing tape around it.

[0094] (Ground wire protection layer) The grounding wire protection layer 760, for example, has insulating properties and is provided to cover the outer circumference of the grounding wire 190 at a position close to the shielding connection portion 600. This ensures that the insulation near the end of the grounding wire 190 is maintained.

[0095] The grounding wire protection layer 760 includes, for example, putty tape, similar to the filling portion 720. The grounding wire protection layer 760 is formed, for example, by wrapping the putty tape multiple times around the outer circumference of the grounding wire 190 and the power cable 100.

[0096] For example, a pair of grounding wire protection layers 760 are provided. Each pair of grounding wire protection layers 760 is provided on the outer circumference of the pair of grounding wires 190 in a region that overlaps with the first filling portion 720a and the second filling portion 720b.

[0097] (inner protective layer) The inner protective layer 430 is, for example, insulating and is provided to continuously cover the outer perimeter of an area that includes, in this order, the grounding wire 190, the shielding connection part 600 to which the cable metal shielding layer 150 of the first power cable 100a is connected, the first spacer 500a, the insulating unit 300, the second spacer 500b, the shielding connection part 600 to which the cable metal shielding layer 150 of the second power cable 100b is connected, and the grounding wire 190, from the area near the first power cable 100a to the area near the second power cable 100b. The inner protective layer 430 is provided, for example, by having an insulating self-fusing tape and wrapping the self-fusing tape around it. Note that the inner protective layer 430 may be provided in multiple layers. Such an inner protective layer 430 ensures insulation in the outer portion of the cable connection structure 20.

[0098] (Waterproof heat shrink tubing layer) The water-impermeable heat-shrinkable tubing layer 450 is composed of, for example, a heat-shrinkable tube having a metal water-impermeable layer and a resin layer. The water-impermeable heat-shrinkable tubing layer 450 is provided to continuously cover the entire area, including the inner protective layer 430. By covering the entire cable connection structure 20 in this way, damage to the cable connection structure 20 can be suppressed, and the shape stability and water-impermeable properties of the cable connection structure 20 can be ensured.

[0099] (4) Method for manufacturing cable connection structures (method for manufacturing linked power cables, method for connecting cables) Next, with reference to Figures 1 to 6B, a method for manufacturing the cable connection structure 20 according to this embodiment will be described.

[0100] The manufacturing method for the cable connection structure 20 of this embodiment includes, for example, a preparation step S10, a conductor connection step S20, an insulating unit placement step S30, an insulating unit external formation step S40, a shielding connection step S50, and a protective part formation step S60.

[0101] (S10: Preparation process) First, prepare the components for each layer of the cable connection structure 20: a pair of power cables 100, a sleeve 200, an insulating unit 300, a spacer 500, and a protective section 400.

[0102] For example, in the factory, with the insulating unit 300 supported by either the vertical first end face 390a or the second end face 390b of the insulating unit 300, an expanding pipe is hydraulically inserted into the hollow portion of the insulating unit 300. This expands the diameter of the insulating unit 300.

[0103] Next, for example, at the power cable 100 installation site, the pair of power cables 100 are peeled off in stages axially from one end of each cable. This exposes the conductor 110, cable insulation layer 130, cable outer semiconducting layer 140, and cable sheath 160 in that order from the tip of the power cable 100.

[0104] Once the components constituting the cable connection structure 20 are prepared, the power cable 100 is passed through the insulating unit 300, and the insulating unit 300 is moved to a predetermined position for the power cable 100.

[0105] (S20: Conductor connection process) Once preparation step S10 is complete, the pair of power cables 100 are butted together inside the sleeve 200 with the axes of their conductors 110 aligned. After butting the pair of power cables 100 together, the conductors 110 of the pair of power cables 100 are compressed and connected by the sleeve 200.

[0106] Alternatively, semiconductive tape may be wrapped around the cable to fill the space between the pair of cable insulation layers 130.

[0107] (S30: Insulation unit placement process) Once the conductor connection process S20 is completed, an insulating unit 300 is installed to maintain the insulation around the sleeve 200, covering the outer circumference of the area including the sleeve 200. Specifically, the insulating unit 300, which has been expanded by an expanding pipe, is moved to a position where it overlaps with the sleeve 200. Once the insulating unit 300 is in the predetermined position, the expanding pipe is gradually withdrawn from the insulating unit 300, gradually reducing the diameter of the insulating unit 300 in the axial direction. In this way, the insulating unit 300 is positioned to cover the outer circumference of the sleeve 200 and a portion of the outer circumference of each of the pair of power cables 100.

[0108] (S40: Insulation unit external formation process) Once the insulating unit 300 is in place, the semiconductive tape layer 480, the second shielding layer 420, the spacer 500, and the first shielding layer 410 are formed on the outside of the insulating unit 300.

[0109] A semiconductive tape layer 480 is formed by wrapping a semiconductive tape around the outer circumference of the exposed portion of the cable outer semiconductive layer 140 of the power cable 100 on the axial outer side of the insulating unit 300.

[0110] After forming the semiconductive tape layer 480, a second shielding layer 420 is formed so as to cover the outer circumference of the exposed portion of the cable outer semiconductive layer 140 of the second power cable 100b and the outer circumference of the semiconductive tape layer 480 provided on the second power cable 100b. The second shielding layer 420 is then connected to the stress cone portion 360 of the insulating unit 300.

[0111] Once the second shielding layer 420 is formed, spacers 500, which gradually decrease in diameter in the direction away from the axial end of the insulating unit along the conductor 110, are arranged to surround the outer circumference of each of the pair of power cables 100 and to be in contact with the axial end of the insulating unit 300.

[0112] Once each spacer 500 is in place, the first shielding layer 410 is formed to continuously cover the outer circumference of the exposed portion of the cable outer semiconductive layer 140 of the first power cable 100a, the outer circumference of the spacer 500, and the outer circumference of the outer semiconductive layer 380 of the insulating unit 300.

[0113] (S50: Shielding connection process) Once the external forming process S40 of the insulating unit is completed, the grounding wire 190, which is to be grounded to the outside, and the cable metal shielding layers 150 of each of the pair of power cables 100 are connected by the shielding connection part 600.

[0114] The specific procedure for the shielding connection process S50 is as follows: First, before directly connecting the grounding wire 190 and the cable metal shielding layer 150, the area between the grounding wire 190 and the power cable 100 is filled with an insulating filler portion 720 at a location close to the planned location of the shielding connection portion 600. For example, the filler portion 720 is formed by wrapping putty tape multiple times around the outer circumference of the power cable 100.

[0115] Once the filling section 720 is in place, the shielding connection section 600 is fixed to the spacer 500. Specifically, the current collector plate 620 is placed on the outer surface of the cylindrical section 540 of the spacer 500. In this state, the current collector plate 620 is tightened against the cylindrical section 540 of the spacer 500 using the band 660.

[0116] After fixing the current collector plate 620 to the spacer 500, terminals 642 are connected by compression to the ends of multiple wire shields 152 of the cable metal shielding layer 150, and the terminals 642 are fastened to the current collector plate 620 with bolts 652. Furthermore, terminal 644 is connected by compression to the end of the grounding wire 190, and the terminals 644 are fastened to the current collector plate 620 with bolts 654.

[0117] Alternatively, the current collector plate 620 may be fixed to the spacer 500 after the terminals 642 and 644 have been fastened to the current collector plate 620.

[0118] (S60: Protective part forming process) Once the shielding connection process S50 is completed, the protective section 400 is formed.

[0119] The specific procedure for the protective part formation step S60 is to first wrap self-fusing tape around the outside of the shielding connection part 600. This forms an insulating tape layer 740 that covers the outside of the shielding connection part 600.

[0120] After forming the insulating tape layer 740, putty tape is wrapped multiple times around the outer circumference of the grounding wire 190 and the power cable 100. This forms a grounding wire protection layer 760 that covers the outer circumference of the grounding wire 190 at a position close to the shielding connection part 600.

[0121] After forming the grounding wire protection layer 760, self-fusing tape is wrapped around the outer circumference of a predetermined area including the insulating unit 300. This forms an inner protection layer 430 that covers the outer circumference of an area including the grounding wire 190, the shielding connection part 600 to which the cable metal shielding layer 150 of the first power cable 100a is connected, the first spacer 500a, the insulating unit 300, the second spacer 500b, the shielding connection part 600 to which the cable metal shielding layer 150 of the second power cable 100b is connected, and the grounding wire 190, in that order, from the area closer to the first power cable 100a to the area closer to the second power cable 100b.

[0122] After forming the inner protective layer 430, a water-impermeable heat-shrinkable tube is placed around the outer circumference of a predetermined area including the insulating unit 300. Once the water-impermeable heat-shrinkable tube is positioned as described above, it is heat-shrinked. This forms a water-impermeable heat-shrinkable tube layer 450 that covers the entire area of ​​the cable connection structure 20.

[0123] Based on the above, the cable connection structure 20 and the connecting power cable 10 of this embodiment are manufactured.

[0124] (5) Summary of this embodiment This embodiment provides one or more of the following effects.

[0125] (a) In this embodiment, the filling portion 720 is insulating and is provided to fill the area between the grounding wire 190 and the power cable 100 at a position close to the shielding connection portion 600. This prevents the formation of an air gap containing air with low insulating strength between the grounding wire 190 and the power cable 100. By preventing the formation of such an air gap, it is possible to prevent the formation of a conductive path from the shielding connection portion 600 to which a high voltage is applied to the earth (for example, the metal waterproofing layer of the waterproofing heat shrinkable tube layer 450). By preventing the formation of such a conductive path, the generation of unintended ground fault currents can be suppressed.

[0126] As a result, in this embodiment, stable insulation of the cable connection structure 20 can be obtained.

[0127] (b) In this embodiment, the filling portion 720 can improve not only the insulation but also the water-blocking properties of the cable connection structure 20.

[0128] In this cable connection structure 20, the end of the water-impermeable heat-shrinkable tubing layer 450 is typically closed with a branch clip (not shown). This structure makes it difficult for water to penetrate from the end of the water-impermeable heat-shrinkable tubing layer 450.

[0129] Furthermore, in this embodiment, since the filling portion 720 is provided to fill the area between the grounding wire 190 and the power cable 100, even if water penetrates into the interior through the end (or minute gap) of the water-impermeable heat-shrinkable tube layer 450, the filling portion 720 can prevent the water from propagating through the area between the grounding wire 190 and the power cable 100. As a result, the water-impermeable properties of the cable connection structure 20 can be further improved.

[0130] (c) In this embodiment, the shielding connection portion 600 connecting the grounding wire 190 and the cable metal shielding layer 150 is fixed to the spacer 500.

[0131] By fixing the shielding connection part 600 to the spacer 500, a series of operations related to connecting the grounding wire 190 and the wire shield 152 can be performed easily and stably. This reduces individual differences among workers and improves the reproducibility of the connection work. As a result, it becomes possible to make the structure connecting the grounding wire 190 and the wire shield 152 of the cable metal shielding layer 150 uniform.

[0132] By fixing the shielding connection part 600 to the spacer 500, it is possible to prevent the terminal 642 connected to the end of the cable metal shielding layer 150 and the terminal 644 connected to the end of the grounding wire 190 from contacting the exposed portion of the cable outer semiconducting layer 140 at the shielding connection part 600. Furthermore, it is possible to eliminate the need to bend the wire shield 152 of the cable metal shielding layer 150 away from the axial end of the conductor 110. This prevents the bent portion of the wire shield 152 from contacting the exposed portion of the cable outer semiconducting layer 140 due to the bending of the wire shield 152. As a result, it is possible to prevent damage to the exposed portion of the cable outer semiconducting layer 140.

[0133] By fixing the shielding connection part 600 to the spacer 500, even if the wire shield 152 of the cable metal shielding layer 150 moves due to heat generated during operation, the range of movement of the wire shield 152 near the shielding connection part 600 can be kept within a certain range. This makes it possible to suppress excessive disturbance of the wire shield 152.

[0134] By fixing the shielding connection portion 600 to the spacer 500, that is, by stabilizing the structure around the shielding connection portion 600, the self-fusing tape as the inner protective layer 430 can be easily and stably wrapped around the outer circumference of the shielding connection portion 600. This suppresses variations in the wrapping of the self-fusing tape in the inner protective layer 430. In other words, it suppresses the occurrence of areas where the self-fusing tape is thin. As a result, it becomes possible to stabilize the electrical characteristics.

[0135] From this perspective as well, it becomes possible to obtain stable insulation for the cable connection structure 20.

[0136] (d) In this embodiment, the filling portion 720 is provided in a position close to the shielding connection portion 600 fixed to the spacer 500, so as to fill the area between the grounding wire 190 connected to the shielding connection portion 600 and the power cable 100.

[0137] In this case, as described above, when the shielding connection part 600 is fixed to the spacer 500, the shielding connection part 600 is fixed on the spacer 500 at a position away from the outer circumference of the power cable 100. Therefore, a gap is likely to occur between the grounding wire 190 connected to the shielding connection part 600 and the power cable 100.

[0138] In contrast, in this embodiment, the filling portion 720 is provided to fill the area between the grounding wire 190 connected to the shielding connection portion 600 and the power cable 100. This prevents the formation of air gaps containing low insulating strength between the grounding wire 190 and the power cable 100, even if the shielding connection portion 600 is fixed on the spacer 500 at a position away from the outer circumference of the power cable 100. As a result, the formation of a conductive path from the shielding connection portion 600 on the spacer 500 to the ground can be prevented.

[0139] (e) In this embodiment, the shielding connection portion 600 is fixed to the spacer 500, which is configured as a molded body. That is, the spacer 500 to which the shielding connection portion 600 is fixed is a molded body with a predetermined outer shape. This allows the shielding connection portion 600 to be stably fixed in a fixed position on the spacer 500. As a result, it is possible to improve the structural stability around the shielding connection portion 600.

[0140] (f) In this embodiment, the shielding connection portion 600 has a current collector plate 620 to which a terminal 642 connected to the end of the cable metal shielding layer 150 and a terminal 644 connected to the end of the grounding wire 190 are connected. This allows the cable metal shielding layer 150 and the grounding wire 190 to be physically connected to the current collector plate 620, and also allows the cable metal shielding layer 150 and the grounding wire 190 to be electrically connected through the current collector plate 620. In other words, the functions required of the shielding connection portion 600 can be concentrated in the current collector plate 620. By fixing the current collector plate 620, in which the functions of the shielding connection portion 600 are concentrated in this way, to the spacer 500, the structural stability near the shielding connection portion 600 can be further improved.

[0141] <Other embodiments of this disclosure> Although embodiments of this disclosure have been described in detail above, this disclosure is not limited to the embodiments described above, and various modifications are possible without departing from its essence.

[0142] In the above-described embodiment, one cable connection structure 20 of the linked power cable 10 was explained. However, the linked power cable 10 may have multiple cable connection structures 20.

[0143] In the embodiments described above, the case in which the cable connection structure 20 is applied to three-phase AC was explained. However, the cable connection structure 20 may also be applied to DC.

[0144] In the embodiments described above, the case in which the spacer 500 contains a thermoplastic resin and has a hollow structure was described, but the disclosure is not limited to this case. The spacer 500 may contain, for example, rubber and have a solid structure. This makes it possible to improve the rigidity near the shielding connection portion 600 fixed to the spacer 500.

[0145] In the embodiments described above, the case in which the spacer 500 has a conical portion 520 and a cylindrical portion 540 was described, but the disclosure is not limited to this case. If the spacer 500 is configured as a molded body, the spacer 500 may have, for example, only a conical portion 520. However, as described above, having both a conical portion 520 and a cylindrical portion 540 allows for more stable fixing of the shielding connection portion 600 to the cylindrical portion 540.

[0146] In the embodiments described above, the case in which the current collector plate 620 is fastened to the spacer 500 by the band 660 has been explained, but the disclosure is not limited to this case. The spacer 500 may be configured, for example, as in the following modifications 1 and 2.

[0147] In Modification 1, the spacer 500 may have, for example, a so-called snap-fit ​​structure. Specifically, the current collector plate 620 has, for example, an engagement hole. On the other hand, the spacer 500 has, for example, an engagement portion. The engagement portion of the spacer 500 is configured to fix the current collector plate 620 to the spacer 500 by engaging with the engagement hole of the current collector plate 620. With this configuration, the engagement portion 590 can be stably engaged with the current collector plate 620.

[0148] In the modified example 2, the current collector plate 620 may be integrally molded with the spacer 500, for example. This further improves the structural stability near the shielding connection portion 600.

[0149] In the above-described embodiment, the case in which the outermost layer of the protective part 400 is a water-impermeable heat-shrinkable tube layer 450 was explained, but this disclosure is not limited to this case. The outermost layer of the protective part 400 may be, for example, a metal pipe (copper pipe). [Explanation of Symbols]

[0150] 10 Power Cables 20 Cable connection structure 100 Power Cables 100a No. 1 Power Cable 100b Second power cable 110 conductor 120 Cable internal semiconducting layer 130 Cable insulation layer 140 Cable outer semiconducting layer 150 Cable metal shielding layer 152 Wire Shield 160 Cable Sheath 190 Ground wire 200 sleeves 300 Insulation Units 320 Internal semiconducting layer 340 Insulation Unit Insulation Layer 360 Stress cone section 380 Outer semiconducting layer 390a 1st end face 390b 2nd end face 400 Protection Department 410 1st shielding layer 420 2nd shielding layer 430 Inner protective layer 450 Water-resistant heat-shrinkable tubing layer 480 Semiconductive Tape Layer 500 Spacer 500a First Spacer 500b Second Spacer 512 1st division 514 Second division 520 Cone section 540 Cylindrical section 560 Gripping part 580 Rib 590 Engaging part 600 Shielding connection 620 Current collector plate 642 terminals 644 terminals 652 volts 654 volts 660 bands 720 Filling section 720a First filling section 720b 2nd filling section 740 Insulating tape layer 760 Ground wire protection layer CA center axis SP separation part

Claims

1. A cable connection structure, A power cable having a conductor, a cable insulation layer, and a cable metal shielding layer in this order from the central axis of the conductor outward, A grounding wire is arranged along the aforementioned power cable and is grounded to the outside, The shielding connection portion of the power cable that connects the cable metal shielding layer and the grounding wire, A filling portion having insulating properties, which fills the area between the ground wire and the power cable at a position close to the shielding connection portion, Equipped with Cable connection structure.

2. The aforementioned power cables are provided in pairs, The aforementioned cable connection structure is, A cylindrical sleeve connecting the conductors of the pair of power cables, A cylindrical insulating unit is provided so as to cover the outer circumference of the region including the sleeve and maintain the insulating properties around the sleeve, A spacer is provided that surrounds the outer circumference of each of the pair of power cables and is in contact with the axial end of the insulating unit, and whose diameter gradually decreases in the direction away from the end of the insulating unit along the conductor, Equipped with, The shielding connection portion is fixed to the spacer. The cable connection structure according to claim 1.

3. The spacer is configured as a molded body. The cable connection structure according to claim 2.

4. The shielding connection portion includes a current collector plate which contains metal and connects a terminal connected to the end of the cable metal shielding layer and a terminal connected to the end of the grounding wire. The current collector plate is fixed to the spacer. The cable connection structure according to claim 2 or claim 3.

5. A cable connection structure comprising at least one of the cable connection structures described in any one of claims 1 to 3. Connecting power cables.

6. A step of preparing a power cable having a conductor, a cable insulation layer, and a cable metal shielding layer in this order from the central axis of the conductor outwards, A step of connecting a grounding wire, which is arranged along the power cable and grounded to the outside, and the cable metal shielding layer of the power cable, by a shielding connection part, Equipped with, In the process of connecting using the aforementioned shielding connection part, The area between the grounding wire and the power cable at a position close to the shielding connection is filled with an insulating filler. A method for manufacturing a cable connection structure.

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