JP2023087145A - Cable connection structure, connection power cable, cable terminal connection structure, manufacturing method for cable connection structure and manufacturing method for cable terminal connection structure - Google Patents

Abstract

To achieve stable connection of a power cable.SOLUTION: A cable connection structure includes: a pair of power cables each having a conductor; a metallic sleeve surrounding a junction point connecting the conductors of the pair of power cables; and a metal strip crossing the sleeve. The sleeve and the conductor have an insertion hole opened up to at least a part of the conductor to cross the conductor from the outer periphery of the sleeve. The metal strip is inserted into the insertion hole from the sleeve up to the conductor to electrically connect the sleeve with the conductor.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a cable connection structure, an interlocking power cable, a cable termination structure, a method of manufacturing a cable connection structure, and a method of manufacturing a cable termination structure.

When connecting a pair of power cables or when terminating power cables, a sleeve may be compression-connected to a connection point of a conductor or to a tip of a conductor (for example, Patent Document 1).

JP-A-11-41779

An object of the present disclosure is to stably connect power cables.

According to one aspect of the present disclosure,
a pair of power cables each having a conductor;
a metal sleeve surrounding a connection point connecting the conductors of the pair of power cables;
a metal strip crossing the sleeve;
has
The sleeve and the conductor have an insertion hole opened from the outer periphery of the sleeve to at least a part of the conductor so as to cross the conductor,
The metal strip is inserted into the insertion hole from the sleeve to the conductor to electrically connect the sleeve and the conductor.

According to another aspect of the present disclosure,
An interlocking power cable is provided comprising at least one cable connection structure as described above.

According to yet another aspect of the present disclosure,
a power cable having a conductor;
a metal sleeve surrounding the tip of the conductor of the power cable;
a metal strip crossing the sleeve;
a porcelain tube into which the power cable to which the sleeve is attached is inserted;
has
The sleeve and the conductor have an insertion hole opened from the outer periphery of the sleeve to at least a part of the conductor so as to cross the conductor,
A cable termination connection structure is provided in which the metal strip is inserted into the insertion hole from the sleeve to the conductor to electrically connect the sleeve and the conductor.

According to yet another aspect of the present disclosure,
providing a pair of power cables each having a conductor;
arranging a metal sleeve so as to surround a connection point where the conductors of the pair of power cables are connected;
intersecting a metal strip against the sleeve;
has
The step of intersecting the metal strips includes:
forming an insertion hole in the sleeve and the conductor from the outer circumference of the sleeve to at least a part of the conductor so as to intersect the conductor;
a step of inserting the metal strip into the insertion hole from the sleeve to the conductor, and electrically connecting the sleeve and the conductor by the metal strip;
A method of manufacturing a cable connection structure is provided.

According to yet another aspect of the present disclosure,
providing a power cable having a conductor;
arranging a metal sleeve to surround the tip of the conductor of the power cable;
intersecting a metal strip against the sleeve;
inserting the power cable with the sleeve attached into a porcelain pipe;
has
The step of intersecting the metal strips includes:
forming an insertion hole in the sleeve and the conductor from the outer circumference of the sleeve to at least a part of the conductor so as to intersect the conductor;
a step of inserting the metal strip into the insertion hole from the sleeve to the conductor, and electrically connecting the sleeve and the conductor by the metal strip;
A method of manufacturing a cable termination structure is provided.

According to the present disclosure, a power cable can be stably connected.

FIG. 1A is a schematic cross-sectional view showing a first example of a power cable; FIG. FIG. 1B is a schematic cross-sectional view showing a second example of the power cable. FIG. 2 is a schematic cross-sectional view along the axial direction of the conductor showing the cable connection structure according to the first embodiment of the present disclosure. FIG. 3 is an enlarged schematic view of the vicinity of the conductor in the cross section of the cable connection structure perpendicular to the axis of the conductor. FIG. 4 is an enlarged schematic view of the vicinity of the conductor in the cross section of the cable connection structure along the axis of the conductor. FIG. 5 is a schematic diagram in which FIG. 4 is further enlarged. FIG. 6 is a flow chart showing a method for manufacturing the cable connection structure according to the first embodiment of the present disclosure. FIG. 7 is a schematic cross-sectional view showing the sleeve placement step. FIG. 8 is a schematic cross-sectional view showing the insertion hole opening step. FIG. 9 is a schematic sectional view showing the step of inserting the metal strip. FIG. 10 is a schematic cross-sectional view showing the cutting process. FIG. 11 is a schematic cross-sectional view along the axial direction of the conductor showing part of the cable connection structure according to Modification 1 of the first embodiment of the present disclosure. FIG. 12 is a schematic cross-sectional view along the axial direction of the conductor showing part of the cable connection structure according to Modification 2 of the first embodiment of the present disclosure. FIG. 13 is an enlarged schematic view of a schematic cross-sectional view along the axial direction of the conductor showing a part of the cable connection structure according to Modification 3 of the first embodiment of the present disclosure. FIG. 14 is a schematic cross-sectional view along the axial direction of the conductor showing the cable termination connection structure according to the second embodiment of the present disclosure;

[Description of Embodiments of the Present Disclosure]
<Knowledge acquired by the inventors, etc.>
First, the findings obtained by the inventors will be described.

In recent years, the application of conductors containing aluminum has been increasing in order to reduce the weight of power cables and reduce the manufacturing cost of power cables. However, when connecting a power cable having the aluminum conductor, since an aluminum oxide film is formed on the outer periphery of the conductor wire, it is necessary to remove the oxide film.

On the other hand, even in a conventional power cable having a conductor containing copper, a conductor wire having an insulating coating on the outer periphery is sometimes used in order to suppress the skin effect of the conductor. Even when connecting such insulated conductors, it is necessary to remove the insulating coating.

As a method for connecting a power cable under the condition that the conductor wire has an oxide film or an insulating film as described above, for example, (i) a method of applying a compound containing metal fine particles to the outer peripheral surface of the conductor, (ii) ) a method of tightening a bolt from the outer peripheral side of the sleeve, and (iii) a method of welding a conductor.

(i) Method of applying a compound In the method of applying a compound to the outer peripheral surface of the conductor, metal fine particles in the compound break through the oxide film or insulating film on the outer peripheral surface of the conductor, thereby removing them to some extent. However, with this method, it is difficult to remove the oxide film or insulating film of the conductor wire inside the outer peripheral surface of the conductor by using a compound. As a result, there is a risk of an increase in electrical resistance and an abnormal temperature rise during energization. On the other hand, in the method of applying the compound, it was necessary to increase the length of the sleeve in the axial direction in order to sufficiently reduce the electrical resistance.

(ii) Method of tightening the bolt In the method of tightening the bolt from the outer peripheral side of the sleeve toward the conductor, the tip of the bolt contacts the outer peripheral surface of the conductor, thereby ensuring conduction between the sleeve and the conductor. However, in this method, the conductive part is limited to the contact point of the bolt with respect to the conductor. Moreover, it was difficult to sufficiently break the oxide film or insulation film of the conductor wire on the flat surface of the tip of the bolt. In addition, due to thermal expansion and contraction during heat cycles, a gap may be formed between the tip of the bolt and the conductor, or an oxide film may be formed in the gap. For this reason, the electrical resistance of the conductor connecting portion tends to increase.

Moreover, in this method, the bolt head protrudes outside the outer peripheral surface of the sleeve, so that the outer diameter of the conductor connecting portion including the bolt increases. In a factory joint (FJ) for connecting a so-called underwater cable or the like, the outermost diameter of the cable connection structure is required to be approximately equal to the outermost diameter of the power cable. For this reason, it has been difficult to apply the structure in which the head protrudes as described above to a factory joint due to the increase in the outer diameter of the conductor connecting portion.

With the above-mentioned configuration in which the tip of the bolt abuts the conductor, even if the bolt head is cut off, the outer diameter of the sleeve and other shapes are maintained to prevent the bolt from coming off. It is thought that the outer diameter will increase. Therefore, in this case as well, application to factory joints is considered to be difficult.

(iii) Method of Welding a Conductor In the method of directly welding a conductor, an increase in electrical resistance or an increase in the outer diameter of the conductor connection occurs compared to the methods (i) and (ii) above. Hateful. However, with this method, there is a possibility that the mechanical strength of the welded portion will be reduced, or that the work time required for welding will be prolonged. For this reason, it has been difficult to apply this method when a large tension is applied to the welded portion, such as in deep-sea installation, or when work time is limited, such as in sea connection.

In addition, in any of the methods (i) to (iii), if a water propagation suppression layer (water running prevention tape) is provided between the conductor wire layers, the water propagation suppression layer is removed. I had to. For this reason, the work itself related to the connection of the power cable is complicated, and the work takes a long time.

The present disclosure is based on the above knowledge discovered by the present disclosure person.

<Embodiments of the Present Disclosure>
Next, embodiments of the present disclosure are listed and described.

[1] A cable connection structure according to an aspect of the present disclosure includes:
a pair of power cables each having a conductor;
a metal sleeve surrounding a connection point connecting the conductors of the pair of power cables;
a metal strip crossing the sleeve;
has
The sleeve and the conductor have an insertion hole opened from the outer periphery of the sleeve to at least a part of the conductor so as to cross the conductor,
The metal strip is inserted into the insertion hole from the sleeve to the conductor to electrically connect the sleeve and the conductor.
According to this configuration, the power cable can be stably connected.

[2] In the cable connection structure described in [1] above,
The metal strip does not protrude outside the outer circumference of the sleeve.
According to this configuration, it is possible to suppress an increase in the outer diameter of the conductor connecting portion.

[3] In the cable connection structure described in [1] or [2] above,
The sleeve is radially compressed on the conductor.
With this configuration, the outer diameter of the conductor connecting portion can be reduced.

[4] In the cable connection structure according to any one of [1] to [3] above,
The conductor in at least one of the pair of power cables has a conductor wire having an oxide coating or an insulating coating on its outer periphery,
The metal strip penetrates at least part of the oxide film or the insulating film of the conductor wire.
According to this configuration, the electrical resistance can be stably reduced.

[5] In the cable connection structure according to any one of [1] to [4] above,
The conductor is
a plurality of conductor strand layers having a plurality of conductor strands;
a water propagation suppression layer that is interposed between the plurality of conductor wire layers and suppresses propagation of water in the conductor;
has
The metal strip penetrates at least a portion of the water propagation suppression layer within the sleeve.
According to this configuration, the work itself relating to the connection of the power cable can be easily performed.

[6] In the cable connection structure according to any one of [1] to [4] above,
The conductor has a plurality of conductor strand layers having a plurality of conductor strands,
a pair of conductor wire layers adjacent in the thickness direction among the plurality of conductor wire layers are in direct contact with each other;
The metal strip penetrates the plurality of conductor wire layers within the sleeve.
Even with this configuration, the plurality of conductor wire layers and the metal strips can be electrically connected.

[7] In the cable connection structure according to any one of [1] to [6] above,
The insertion hole has a thread groove,
The metal strip is screwed into the thread groove of the insertion hole.
With this configuration, the metal strip can be firmly engaged with the sleeve and the conductor.

[8] In the cable connection structure according to any one of [1] to [6] above,
The insertion hole does not have a thread groove,
The metal strip is configured as a metal rod to be inserted into the insertion hole.
According to this configuration, connection work can be simplified.

[9] In the cable connection structure according to any one of [1] to [8] above,
A plurality of the insertion holes are provided so as not to interfere with each other,
A plurality of the metal strips are provided so as to be respectively inserted into the plurality of insertion holes.
According to this configuration, it is possible to reduce the electrical resistance of the conductor connecting portion and improve the strength of the conductor connecting portion.

[10] In the cable connection structure according to any one of [1] to [9] above,
The insertion hole penetrates from the first side wall of the sleeve through the conductor to the second side wall on the opposite side of the first side wall.
According to this configuration, it is possible to reduce the electrical resistance of the conductor connecting portion and improve the strength of the conductor connecting portion.

[11] In the cable connection structure according to any one of [1] to [9] above,
The insertion hole penetrates from a first side wall of the sleeve to the conductor and does not pass through a second side wall opposite the first side wall.
According to this configuration, it is possible to reliably suppress the protrusion of the metal strip from the sleeve.

[12] In the cable connection structure according to any one of [1] to [9] above,
The insertion hole extends from the outer circumference of the sleeve to a part of the conductor, and does not penetrate the conductor.
According to this configuration, it is possible to reliably suppress the protrusion of the metal strip from the sleeve.

[13] A connection power cable according to another aspect of the present disclosure includes:
At least one cable connection structure according to any one of [1] to [12] above.
According to this configuration, the power cable can be stably connected.

[14] A cable termination connection structure according to still another aspect of the present disclosure includes:
a power cable having a conductor;
a metal sleeve surrounding the tip of the conductor of the power cable;
a metal strip crossing the sleeve;
a porcelain tube into which the power cable to which the sleeve is attached is inserted;
has
The sleeve and the conductor have an insertion hole opened from the outer periphery of the sleeve to at least a part of the conductor so as to cross the conductor,
The metal strip is inserted into the insertion hole from the sleeve to the conductor to electrically connect the sleeve and the conductor.
According to this configuration, the power cable can be stably connected.

[15] A method for manufacturing a cable connection structure according to still another aspect of the present disclosure includes:
providing a pair of power cables each having a conductor;
arranging a metal sleeve so as to surround a connection point where the conductors of the pair of power cables are connected;
intersecting a metal strip against the sleeve;
has
The step of intersecting the metal strips includes:
forming an insertion hole in the sleeve and the conductor from the outer circumference of the sleeve to at least a part of the conductor so as to intersect the conductor;
a step of inserting the metal strip into the insertion hole from the sleeve to the conductor, and electrically connecting the sleeve and the conductor by the metal strip;
have
According to this configuration, the power cable can be stably connected.

[16] A method for manufacturing a cable termination connection structure according to still another aspect of the present disclosure includes:
providing a power cable having a conductor;
arranging a metal sleeve to surround the tip of the conductor of the power cable;
intersecting a metal strip against the sleeve;
inserting the power cable with the sleeve attached into a porcelain pipe;
has
The step of intersecting the metal strips includes:
forming an insertion hole in the sleeve and the conductor from the outer circumference of the sleeve to at least a part of the conductor so as to intersect the conductor;
a step of inserting the metal strip into the insertion hole from the sleeve to the conductor, and electrically connecting the sleeve and the conductor by the metal strip;
have
According to this configuration, the power cable can be stably connected.

[Details of the embodiment of the present disclosure]
Next, one embodiment of the present disclosure will be described below with reference to the drawings. The present disclosure is not limited to these examples, but is indicated by the scope of the claims, and is intended to include all modifications within the scope and meaning equivalent to the scope of the claims.

<One embodiment of the present disclosure>
(1) Coupling Power Cable and Cable Connection Structure Schematic configurations of coupling power cable 10 and cable connection structure (cable connection portion) 20 according to an embodiment of the present disclosure will be described with reference to FIGS. 1A, 1B, and 2 . do. 1A and 1B are schematic cross-sectional views showing first and second examples of power cables, respectively. In addition, each of FIG. 1A and FIG. 1B shows a portion of the power cable other than the cable connection structure. FIG. 2 is a schematic cross-sectional view along the axial direction of the conductor showing the cable connection structure according to this embodiment.

In addition, in FIG. 2 , the side surfaces of the power cable 100 other than the conductor 110 are stripped. Since FIGS. 1A to 5 are only schematic diagrams, the number, thickness, spacing, shape, etc. of each part shown in each diagram may differ from the actual situation. Further, the lower side of each of FIG. 2 and FIG. 7 described later is omitted.

As shown in FIG. 2 , the coupling power cable 10 of this embodiment has, for example, a plurality of power cables 100 and at least one cable connection structure 20 .

In addition, hereinafter, the “axial direction” of the power cable 100 or the like refers to the direction along the central axis of the power cable 100 or the like, and can be rephrased as the longitudinal direction of the power cable 100 or the like. Also, the “radial direction” of the power cable 100 or the like refers to the direction perpendicular to the axial direction of the power cable 100 or the like, and in some cases can be rephrased as the lateral direction of the power cable 100 or the like. Moreover, the “circumferential direction” of the power cable 100 or the like refers to the direction along the outer periphery of the power cable 100 or the like.

[Power cable]
As shown in FIG. 1A or 1B, the power cable 100 is configured as a solid insulated cable (CE cable: Crosslinked polyethylene (PE) insulated PE sheathed cable, also referred to as XLPE cable) that is a high-voltage power transmission cable.

A power cable 100 as a first example shown in FIG. 1A is configured, for example, as a land cable or an underground cable, and includes a conductor 110, a cable inner semiconducting layer 120, a cable insulating layer 130, a cable outer semiconducting layer 140, and a water absorption layer. (not shown), a cable metal shielding layer 150, and a cable sheath 160 in this order from the central axis side of the conductor 110 toward the outer peripheral side. A portion of the power cable 100 from the conductor 110 to the cable outer semi-conductive layer 140 is sometimes called a "cable core". The cable metal shield layer 150 is, for example, a metal sheath or a wound layer of copper wire or copper tape.

A power cable 100 as a second example shown in FIG. 1B is configured, for example, as an underwater cable (submarine cable, submarine cable, etc.), and includes a conductor 110, a cable inner semiconducting layer 120, a cable insulating layer 130, and a cable outer semiconducting layer. 140 , a water absorption layer (not shown), a cable metal shielding layer 150 , and a cable outer structure 170 are provided in this order from the central axis side of the conductor 110 toward the outer peripheral side. The cable outer structure 170 for an underwater cable has, for example, an anticorrosion layer, a floor yarn layer, an iron wire armor (armor), and a yarn layer from the cable metal shielding layer 150 side toward the outer peripheral side. In addition, the cable metal shielding layer 150 in the underwater cable is, for example, a metal covering.

In the following, for the sake of simplification of explanation, it is assumed that the outer side of the cable metal shielding layer 150 is the cable sheath 160 .

The conductor 110 has, for example, multiple conductor wire layers 114 and multiple water propagation suppression layers 116 .

Each of the plurality of conductor strand layers 114 has, for example, a plurality of conductor strands 112 . In each conductor wire layer 114, a plurality of conductor wires 112 are helically twisted, for example, along the outer peripheral surface of the inner layer.

The conductor wire 112 in at least one of the pair of power cables 100 has, for example, an oxide coating or an insulating coating on its outer periphery. Specifically, in this embodiment, in both power cables 100, the conductor wire 112 contains, for example, aluminum or an aluminum alloy and has an aluminum oxide film on the outer periphery.

For example, the water propagation suppression layer 116 is interposed between the plurality of conductor wire layers 114 and provided so as to cover the outer periphery of the inner conductor wire layer 114 . Water propagation suppression layer 116 is configured, for example, to inhibit water propagation within conductor 110 . Specifically, the water propagation suppression layer 116 is made of, for example, a so-called water running prevention tape. The water running prevention tape is a tape impregnated with a water-absorbing material (water-absorbing polymer). It prevents running water.

As shown in FIG. 2, the power cable 100 is stripped in stages from the tip of the conductor 110 toward the opposite side (so-called "step stripping"). That is, the conductor 110, the cable inner semiconductive layer 120, the cable insulating layer 130, the cable outer semiconductive layer 140, the cable metal shield layer 150, and the cable sheath 160 are arranged in this order from the tip side of the conductor 110 toward the opposite side. Exposed. Hereinafter, each portion that has been stepped off may be referred to as an “exposed portion”. With such a configuration, the power cables 100 can be connected in order from the central axis side to the outer peripheral side.

Conductor 110 , cable inner semiconductive layer 120 , cable insulation layer 130 , cable outer semiconductive layer 140 , and cable metal shield layer 150 are cut obliquely to the axis of conductor 110 . In other words, the power cable 100 is processed into a pencil shape, for example, and has a conical exfoliation surface (not shown) that expands in diameter from the tip of the conductor 110 toward the opposite side.

As shown in FIG. 2, a plurality of power cables 100 are provided. A pair of power cables 100 among the plurality of power cables 100 are butted against each other with the axes of the conductors 110 aligned. In the following, one power cable 100 of the pair of power cables 100 may be called "first power cable 100a" and the other power cable 100 may be called "second power cable 100b".

[Cable connection structure]
As shown in FIG. 1, the cable connection structure 20 is configured to connect, for example, a pair of power cables 100, and is configured as a so-called factory joint. Specifically, the cable connection structure 20 includes, for example, the above-described pair of power cables 100, the sleeve 210, the metal strip 214, the inner semiconductive layer 220, the insulating layer 230, the outer semiconductive layer 240, It has a water absorbing tape layer 242 , a metal tube (protective tube) 250 and an anticorrosion layer (connection sheath) 260 .

(Sleeve (conductor connecting tube))
In this embodiment, the sleeve 210 is provided, for example, so as to surround a connection point where the conductors 110 of the pair of power cables 100 are connected. The term “connection point (connection portion)” as used herein means a point (portion, location) where a pair of conductors 110 are brought into contact with their axes facing each other, and the tip surfaces of the conductors 110 are in surface contact. In that sense, it can also be called a “connection surface”.

In this embodiment, the sleeve 210 is configured as, for example, a metal cylindrical member having a hollow portion (not shown). The exposed portions of the pair of conductors 110 including connection points are inserted into the hollow portion of the sleeve 210 .

Examples of the metal forming the sleeve 210 include copper (pure copper), copper alloy, aluminum, and aluminum alloy. If the sleeve 210 is made of aluminum or an aluminum alloy, it is preferable to increase the thickness of the sleeve 210 so that the electrical resistance per cross-sectional area is equivalent to that of pure copper.

In this embodiment, the sleeve 210 is, for example, compressed radially of the conductor 110 . Thereby, the conductors 110 of the pair of power cables 100 are compression-connected by the sleeve 210 . Also, the inner peripheral surface of the sleeve 210 is in contact with the outer peripheral surface of the conductor 110 .

(Metal strips (headless bolts, threaded bolts))
The metal strip 214 is provided, for example, so as to cross the sleeve 210 . In addition, hereinafter, the portion where the pair of conductors 110 are connected by the sleeve 210 and the portion including the metal strip 214 is also referred to as a “conductor connection portion”. Details of the conductor connecting portion will be described later.

(Internal semi-conductive layer)
As shown in FIG. 2, the inner semi-conductive layer 220 is provided so as to cover the outer circumference of the sleeve 210 . The inner semi-conductive layer 220 has semi-conductive properties. Thereby, electric field concentration near the surface of the sleeve 210 can be relaxed.

In this embodiment, the inner semi-conductive layer 220 comprises, for example, a semi-conductive tape wrapped around the outer circumference of the sleeve 210 .

(insulating layer)
As shown in FIG. 2, the insulating layer 230 is provided so as to cover the outer circumference of the inner semi-conductive layer 220 . The insulating layer 230 has insulating properties. This ensures insulation on the outside of the sleeve 210 .

In this embodiment, insulating layer 230 covers, for example, inner semi-conductive layer 220 and exposed portions of cable insulating layer 130 . The insulating layer 230 has, for example, a conical surface whose diameter expands from the ends of the insulating layer 230 in the axial direction of the conductor 110 toward the center.

In this embodiment, the insulating layer 230 is composed of, for example, an insulating tape wrapped around the exposed portions of the inner semi-conductive layer 220 and the cable insulating layer 130 .

(outer semiconducting layer)
As shown in FIG. 2, the outer semi-conductive layer 240 is provided so as to cover the outer periphery of the insulating layer 230 . The outer semiconducting layer 240 is semiconducting. As a result, electric field concentration near the outside of the insulating layer 230 can be relaxed.

In this embodiment, the outer semi-conductive layer 240 is composed of, for example, a semi-conductive tube covering the outer periphery of the cable insulation layer 130 .

In this embodiment, the outer semi-conductive layer 240 is in contact with the exposed end of the cable outer semi-conductive layer 140 while covering the outer circumference of the insulating layer 230 . As a result, the outer semi-conductive layer 240 is electrically equipotential to the cable outer semi-conductive layer 140 .

(Water absorbing tape layer)
As shown in FIG. 2, the water absorbing tape layer 242 is provided, for example, so as to cover the outer periphery of the outer semi-conductive layer 240 . The water absorbing tape layer 242 is constructed in the same manner as the water absorbing layer of the power cable 100 . Thereby, propagation of water in the metal pipe 250 can be suppressed.

(metal tube)
As shown in FIG. 2, the metal tube 250 is provided so as to cover the outer circumference of the external semiconductive layer 240 (water absorbing tape layer 242). Examples of the metal forming the metal tube 250 include lead and aluminum. By providing such a metal tube 250, the impact resistance of the cable connection structure 20 can be improved.

(Anti-corrosion layer)
As shown in FIG. 2 , the anticorrosion layer 260 is provided so as to cover the outer circumference of the metal tube 250 and the exposed portion of the cable metal shielding layer 150 . The anticorrosion layer 260 is made of a resin (such as PE) having anticorrosion properties. Corrosion of the cable core can thereby be suppressed.

(2) Conductor Connection Part The configuration of the conductor connection part in the cable connection structure 20 of the present embodiment will be described with reference to FIGS. 3 to 5. FIG. FIG. 3 is an enlarged schematic view of the vicinity of the conductor in the cross section of the cable connection structure perpendicular to the axis of the conductor. FIG. 4 is an enlarged schematic view of the vicinity of the conductor in the cross section of the cable connection structure along the axis of the conductor. FIG. 5 is a schematic diagram in which FIG. 4 is further enlarged.

As shown in FIGS. 3-5, in this embodiment, sleeve 210 and conductor 110 have insertion holes 212, for example. The insertion hole 212 is formed, for example, from the outer periphery of the sleeve 210 to at least a portion of the conductor 110 so as to intersect the conductor 110 .

The metal strip 214 is inserted into the insertion hole 212 from the sleeve 210 to the conductor 110, for example. The metal strip 214 can electrically connect the sleeve 210 and the conductor 110 .

In addition, in this embodiment, as will be described later, the metal strip 214 does not protrude outside the outer periphery of the sleeve 210 by cutting the extending portion of the metal strip 214 outside the outer periphery of the sleeve 210. . As a result, an increase in the outer diameter of the conductor connecting portion including the metal strip 214 can be suppressed.

Moreover, in this embodiment, the insertion hole 212 penetrates, for example, from the first side wall 210a of the sleeve 210 through the conductor 110 to the second side wall 210b on the opposite side of the first side wall 210a. A metal strip 214 is inserted over the entire insertion hole 212 penetrating through them. Thereby, the metal strip 214 can be engaged with both the first side wall 210 a and the second side wall 210 b of the sleeve 210 .

Moreover, in this embodiment, the insertion hole 212 is preferably provided so as to intersect the central axis of the conductor 110, for example. That is, it is preferable that the metal strip 214 inserted into the insertion hole 212 intersects the central axis of the conductor 110 . Thereby, the engagement length of the metal strip 214 with respect to the conductor 110 can be lengthened. As a result, the strength of the conductor connecting portion can be improved. Also, since the metal strips 214 and the central axes of the conductors 110 are not misaligned, twisting of the conductors 110 , the sleeve 210 , and the metal strips 214 can be suppressed when a tensile force is applied to the pair of conductors 110 .

It is more preferable that the metal strip 214 inserted into the insertion hole 212 is perpendicular to the center axis of the conductor 110 . Thereby, the strength of the conductor connecting portion can be improved.

Moreover, as shown in FIG. 5, in this embodiment, the insertion hole 212 has, for example, a screw groove (not shown). The metal strip 214 has, for example, a thread groove on its outer periphery and is screwed into the thread groove of the insertion hole 212 . This allows the metal strip 214 to be firmly engaged with the sleeve 210 and the conductor 110 .

Moreover, in this embodiment, the insertion hole 212 is provided so as to penetrate at least a part of the oxide film of the conductor wire 112, for example. That is, the metal strip 214 inserted into the insertion hole 212 penetrates at least part of the oxide film of the conductor wire 112 . As a result, the inside of the conductor wire 112 having a low electrical resistance can be directly connected to the metal strip 214 instead of the outer peripheral surface of the conductor wire 112 forming the conductor 110 . As a result, electrical resistance can be stably reduced.

In addition, in the present embodiment, the insertion hole 212 is formed in a state where the conductor 110 has the water propagation suppression layer 116 , so that the insertion hole 212 is formed inside (the hollow portion of) the sleeve 210 , for example, the water propagation suppression layer 116 . 116 is provided so as to penetrate at least a portion thereof. That is, the metal strip 214 inserted into the insertion hole 212 penetrates at least part of the water propagation suppression layer 116 . Thereby, the step of removing the water propagation suppression layer 116 can be omitted.

Moreover, in this embodiment, for example, a plurality of insertion holes 212 are provided. A plurality of insertion holes 212 are provided so as not to interfere with each other. The plurality of insertion holes 212 are provided, for example, at predetermined intervals in the axial direction of the conductor 110 . A plurality of metal strips 214 are provided so as to be inserted into the plurality of insertion holes 212 respectively. As a result, the strength of the conductor connecting portion can be improved and the electrical resistance can be reduced.

Furthermore, in the present embodiment, the plurality of insertion holes 212 are spirally provided in the axial direction of the conductor 110, for example. That is, the plurality of insertion holes 212 are arranged in the circumferential direction (clockwise or counterclockwise) of the conductor 110 as the direction of insertion of the metal strips 214 viewed from the axial direction of the conductor 110 moves away from the axial direction of the conductor 110. They are arranged so that they are gradually shifted. Thereby, the engagement positions of the metal strips 214 with respect to the sleeve 210 and the conductor 110 can be evenly arranged. That is, the tensile force during installation can be evenly distributed.

The insertion angle of the metal strip 214 in the spiral arrangement described above is not particularly limited. However, of the two metal strips 214 adjacent to each other in the axial direction of the conductor 110, the angle of the insertion direction of the second metal strip 214 with respect to the insertion direction of the first metal strip 214 is, for example, is 20° or more and 80° or less, preferably 60°. By setting such an angle, the strength of the conductor connecting portion can be improved.

Further, as shown in FIG. 5, in this embodiment, the sleeve 210 is compressed in the radial direction of the conductor 110 with the metal strip 214 inserted. Thereby, the outer diameter of the conductor connecting portion can be reduced.

Note that the central axis of the metal strip 214 may be straight within the sleeve 210 , or at least a portion of the central axis of the metal strip 214 may be linear within the sleeve 210 due to compression of the sleeve 210 . It may be curved. Since the center axis of the metal strip 214 is straight within the sleeve 210 , rigidity can be maintained against tensile stress in the axial direction of the power cable 100 . On the other hand, since at least a portion of the central axis of metal strip 214 is bent within sleeve 210 , the anchoring effect of metal strip 214 to conductor 110 within sleeve 210 can be improved. In the latter case, the other portion of the metal strip 214 may have a portion where the central axis is not bent.

Although the material of the metal strip 214 is not particularly limited, for example, the following can be considered.

The metal strip 214 may contain copper, for example, and preferably may contain a material close to pure copper. Thereby, the electrical resistance can be reduced while ensuring the mechanical strength. Even if a metal strip 214 made of a dissimilar metal is used to connect the aluminum conductor 110, electrolytic corrosion is unlikely to occur because the outside of the conductor connecting portion is sealed.

On the other hand, the metal strip 214 may contain aluminum, for example. By contacting the same kind of metal as the conductor 110 as the metal strip 214, electrolytic corrosion can be suppressed even if water enters the conductor connecting portion. In this case, the metal strip 214 is preferably inserted into the insertion hole 212 after removing the aluminum oxide film.

In this embodiment, the outermost diameter of the cable connection structure 20 is approximately equal to the outermost diameter of the power cable 100, for example, because the conductor connection portion has the above-described configuration. Specifically, the outermost diameter of anticorrosion layer 260 in a cross section including sleeve 210 and perpendicular to the axis of power cable 100 is, for example, +20 mm or less with respect to the outermost diameter of power cable 100 . In addition, in the present embodiment, the outermost diameter of the anticorrosion layer 260 can be, for example, equal to or less than the outermost diameter in the above-described (iii) conductor welding method.

(3) Cable connection structure manufacturing method (connection power cable manufacturing method, cable connection method)
Next, a method for manufacturing the cable connection structure 20 according to this embodiment will be described with reference to FIGS. 1 to 9. FIG. FIG. 6 is a flow chart showing the method for manufacturing the cable connection structure according to this embodiment. A step is abbreviated as "S". FIG. 7 is a schematic cross-sectional view showing the sleeve placement step. FIG. 8 is a schematic cross-sectional view showing the insertion hole opening step. FIG. 9 is a schematic sectional view showing the step of inserting the metal strip. FIG. 10 is a schematic cross-sectional view showing the cutting process.

As shown in FIG. 6, the method for manufacturing the cable connection structure 20 of this embodiment includes, for example, a preparation step S100, a sleeve placement step S220, a metal strip crossing step S240, and an outer forming step S300. there is

[S100: Preparatory step]
First, a plurality of power cables 100 are prepared.

Specifically, the power cable 100 is peeled off step by step from the tip of the conductor 110 toward the opposite side. At this time, the power cable 100 is processed into a pencil shape to form a conical exfoliation surface that expands in diameter from the tip of the conductor 110 toward the opposite side.

After the step stripping of the pair of power cables 100 is completed, for example, the first power cable 100 a is inserted through the outer semi-conductive layer 240 , the metal tube 250 and the anti-corrosion layer 260 .

[S220: Sleeve placement step]
After the preparation step S100 is completed, as shown in FIG. 7, a metal sleeve 210 is arranged so as to surround the connection point where the conductors 110 of the pair of power cables 100 are connected. That is, the exposed portions of the pair of conductors 110 including connection points are inserted into the hollow portion of the sleeve 210 .

[S240: Metal strip crossing step]
After the sleeve arrangement step S220 is completed, the metal strip crossing step S240 of crossing the metal strip 214 with respect to the sleeve 210 is performed.

In this embodiment, the metal strip crossing step S240 includes, for example, a temporary compression step S241, an insertion hole opening step S242, a metal strip insertion step S243, and an end determination step S244.

(S241: temporary compression step)
As described above, the sleeve 210 is temporarily compressed in the radial direction of the conductor 110 while the sleeve 210 is arranged outside the connection point of the conductor 110 .

In the insertion hole opening step S242, which will be described later, the sleeve 210 is compressed so that the sleeve 210 and the conductor 110 are not displaced. Therefore, it is not necessary to compress the sleeve 210 excessively, and it is sufficient to fix the sleeve 210 against the conductor 110 so that it does not shift. Although the pressure in the temporary compression step S241 is not limited, it is, for example, about 20 MPa.

At this time, in each power cable 100, the sleeve 210 is gradually compressed toward the far side from the connection point of the conductor 110 (the tip side of each). This allows each conductor 110 to extend farther from the connection point as the diameter of the conductor 110 decreases.

(S242: Insertion hole opening step)
Next, as shown in FIG. 8 , in the sleeve 210 and the conductor 110 , an insertion hole 212 is formed from the outer periphery of the sleeve 210 to at least a portion of the conductor 110 so as to intersect the conductor 110 .

At this time, in this embodiment, for example, the insertion hole 212 is made to penetrate from the first side wall 210a of the sleeve 210 to the second side wall 210b on the opposite side of the first side wall 210a through the conductor 110 . Also, at this time, an insertion hole 212 is formed so as to cross the central axis of the conductor 110 .

At this time, in the present embodiment, for example, first, a drill hole (drilled hole, cylindrical hole) is formed as the insertion hole 212 by drilling. Next, a screw groove is formed by tapping along the drilled hole as the insertion hole 212 .

At this time, in the present embodiment, for example, the insertion hole 212 is formed so as to penetrate at least part of the oxide film of the conductor wire 112 .

At this time, in this embodiment, for example, the insertion hole 212 is formed in the sleeve 210 and the conductor 110 while the conductor 110 has the water propagation suppression layer 116 . As a result, the insertion hole 212 is formed so as to penetrate at least a portion of the water propagation suppression layer 116 within (the hollow portion of) the sleeve 210 .

(S243: Metal strip insertion step)
Next, a metal strip 214 is inserted into the insertion hole 212 from the sleeve 210 to the conductor 110 . The metal strip 214 electrically connects the sleeve 210 and the conductor 110 .

At this time, in this embodiment, the metal strip 214 is screwed into the screw groove of the insertion hole 212 described above. Specifically, first, the double nut 219 is attached near the upper end of the metal strip 214 and the double nut 219 is fixed to the metal strip 214 . The metal strip 214 is inserted into the insertion hole 212 by screwing the fixed double nut 219 toward the conductor 110 .

At this time, in this embodiment, the metal strip 214 is inserted into the insertion hole 212 so as to penetrate at least a portion of the water propagation suppression layer 116 inside (the hollow portion of) the sleeve 210 .

At this time, in the present embodiment, the metal strip 214 is inserted over the entire insertion hole 212 penetrating from the first side wall 210a of the sleeve 210 to the second side wall 210b via the conductor 110 . This causes the metal strip 214 to engage both the first side wall 210 a and the second side wall 210 b of the sleeve 210 .

Immediately after the metal strip 214 is inserted, the extending portion (surplus length portion) of the metal strip 214 protrudes outside the outer circumference of the sleeve 210 .

(S244: end determination step)
When the insertion of the predetermined metal strip 214 is completed, it is determined whether or not to finish opening the insertion hole 212 and inserting the metal strip 214 .

If the opening of the predetermined number of insertion holes 212 and the insertion of the predetermined number of metal strips 214 have not been completed (No in S244), the insertion holes 212 and the metal strips 214 are inserted at positions different from the previously formed insertion holes 212 and metal strips 214. A hole forming step S242 and a metal strip inserting step S243 are performed.

In this way, in this embodiment, a plurality of insertion holes 212 are sequentially formed, and metal strips 214 are inserted into each of the plurality of insertion holes 212 .

Further, in this embodiment, for example, a plurality of insertion holes 212 are sequentially formed spirally in the axial direction of the conductor 110 , and the metal strips 214 are inserted into the respective insertion holes 212 .

(S245: cutting step)
When the opening of the predetermined number of insertion holes 212 and the insertion of the predetermined number of metal strips 214 are completed (Yes in S244), as shown in FIG. Cut off the existing part. At this time, it is preferable to cut the metal strip 214 so that the upper surface of the metal strip 214 forms the same plane as the outer peripheral surface of the sleeve 210 . In this manner, protrusion of the metal strip 214 to the outside of the outer circumference of the sleeve 210 is suppressed.

(S246: main compression step)
After the cutting step S245 is completed, the sleeve 210 is fully compressed in the radial direction of the conductor 110 with the metal strip 214 inserted into the insertion hole 212 formed in the sleeve 210 and the conductor 110, as shown in FIG. The term "main compression" as used herein means compression further than temporary compression to reduce the outer diameter of the conductor connecting portion. The pressure in the main compression step S246 is not limited, but is, for example, 50 MPa or more, preferably about 70 MPa.

At this time, the sleeve 210 of each power cable 100 is gradually compressed toward the far side from the connection point of the conductor 110, similarly to the order in the temporary compression step S241. This allows each conductor 110 to extend farther from the connection point as the diameter of the conductor 110 decreases.

A conductor connecting portion is formed by the metal strip crossing step S240 described above.

[S300: Outer forming step]
After forming the conductor connection, the outside of the conductor connection is formed.

Specifically, after forming the conductor connecting portion, an inner semiconductive layer 220 having semiconductivity is formed so as to cover the outer circumference of the sleeve 210 . After forming the inner semi-conducting layer 220, the inner semi-conducting layer 220 is cross-linked, if necessary.

Next, an insulating layer 230 having insulating properties is formed so as to cover the outer periphery of the inner semiconductive layer 220 .

After forming the insulating layer 230 , an external semiconductive layer 240 having semiconductivity is formed so as to cover the outer periphery of the insulating layer 230 .

Once the outer semi-conductive layer 240 is formed, the cable core is heated to crosslink the insulating layer 230 and the like.

After cross-linking, a metal tube 250 made of metal is formed so as to cover the outer periphery of the external semi-conductive layer 240 .

After that, an anticorrosion layer 260 is formed so as to cover the outer periphery of the metal pipe 250 .

As described above, as shown in FIG. 1, the cable connection structure 20 of the present embodiment is manufactured.

(4) Effects According to the Present Embodiment According to the present embodiment, one or more of the following effects can be obtained.

(a) In this embodiment, the sleeve 210 and the conductor 110 have an insertion hole 212 that extends from the outer periphery of the sleeve 210 to at least a portion of the conductor 110 so as to intersect the conductor 110 . A metal strip 214 is inserted into the insertion hole 212 from the sleeve 210 to the conductor 110 to electrically connect the sleeve 210 and the conductor 110 .

In the (i) method of applying compound or (ii) method of tightening bolts described above, the sleeve was electrically connected to the outer peripheral surface of the conductor via metal particles or bolts in the compound. In other words, the conducting portion is limited to the outer peripheral surface of the conductor. In addition, at the conductive portion, the oxide film or insulating film of the conductor wire tends to remain interposed. As a result, the electrical resistance of the conductor connecting portion was high.

On the other hand, in the present embodiment, the sleeve 210 and the conductor 110 are electrically connected via the metal strip 214 inserted into the insertion hole 212, so that the metal strip 214 is electrically conductive throughout the axial direction. A place can be secured. That is, it is possible to increase the conductive portions of the metal strip 214 with respect to the sleeve 210 and the conductive portions with respect to the conductor 110 . Thereby, the electrical resistance at the conductor connecting portion can be reduced. As a result, it is possible to suppress abnormal heat generation at the conductor connecting portion.

(b) In the present embodiment, by increasing the conductive locations in the conductor connection portion in the radial direction of the conductor 110, compared to the above-described (i) method of applying a compound, while reducing the electrical resistance, the sleeve 210 Axial length can be shortened. As a result, it becomes possible to suppress an increase in the cable connection structure 20 .

(c) In the present embodiment, the metal strip 214 does not protrude outside the outer periphery of the sleeve 210 by cutting the extending portion of the metal strip 214 to the outside of the sleeve 210 . As a result, an increase in the outer diameter of the conductor connecting portion including the metal strip 214 can be suppressed. That is, the outer diameter of the conductor connecting portion of the present embodiment can be made smaller than the outer diameter of the conductor connecting portion when the head of the bolt is left by the method (ii) of tightening the bolt described above.

By reducing the outer diameter of the conductor connection portion, the outermost diameter of the cable connection structure 20 as a whole can be made approximately equal to the outermost diameter of the power cable 100 . As a result, it can be applied to so-called submarine cables.

(d) In this embodiment, the insertion holes 212 are formed in the sleeve 210 and the conductor 110, and by inserting the metal strips 214 into the insertion holes 212, electrical continuity between them can be easily ensured. As a result, compared to the method (iii) of welding the conductors described above, it is possible to shorten the working time for forming the conductor connection portion. As a result, for example, it is possible to easily perform the work of connecting submarine cables on the ocean.

(e) In this embodiment, the metal strip 214 is inserted into the insertion hole 212 from the sleeve 210 to the conductor 110, so that the metal strip 214 can be engaged with both the sleeve 210 and the conductor 110. can. As a result, the strength (tensile strength) of the conductor connecting portion can be improved compared to the method (iii) of welding the conductors described above. As a result, for example, it can be applied to a case where a large tension is applied to the conductor connecting portion, such as deep sea installation.

(f) In this embodiment, the sleeve 210 is compressed in the radial direction of the conductor 110 with the metal strip 214 inserted. As a result, the outer diameter of the conductor connecting portion including the metal strip 214 can be reduced. As a result, the cable connection structure 20 of the present embodiment can be suitably applied to FJs of submarine cables, etc., where the outermost diameter of the cable connection structure is required to be approximately the same as the outermost diameter of the power cable. becomes.

(g) In this embodiment, the insertion hole 212 is provided so as to penetrate at least a portion of the oxide film or insulating film of the conductor wire 112 . That is, the metal strip 214 inserted into the insertion hole 212 penetrates at least part of the oxide film or insulating film of the conductor wire 112 . As a result, the inside of the conductor wire 112 having a low electrical resistance can be directly connected to the metal strip 214 instead of the outer peripheral surface of the conductor wire 112 forming the conductor 110 . As a result, electrical resistance can be stably reduced.

(h) In this embodiment, by opening the insertion hole 212 in the state where the conductor 110 has the water propagation suppression layer 116, the insertion hole 212 is positioned inside the (hollow portion of) the sleeve 210 and the water propagation suppression layer 116. is provided so as to penetrate at least a portion of the That is, the metal strip 214 inserted into the insertion hole 212 penetrates at least part of the water propagation suppression layer 116 . Thereby, the plurality of conductor wire layers 114 and the metal strips 214 can be electrically connected while omitting the step of removing the water propagation suppression layer 116 . As a result, the work itself relating to the connection of the power cable 100 can be easily performed, and the work time can be shortened.

(i) In this embodiment, the insertion hole 212 has a screw groove. The metal strip 214 has a thread groove on its outer periphery and is screwed into the thread groove of the insertion hole 212 . This allows the metal strip 214 to be firmly engaged with the sleeve 210 and the conductor 110 . As a result, it is possible to improve the strength of the conductor connecting portion. Moreover, it is possible to prevent the metal strip 214 from coming out of the insertion hole 212 .

Further, by screwing the metal strip 214 into the screw groove of the insertion hole 212, the contact area between the metal strip 214 and the sleeve 210 and the conductor 110 can be increased. As a result, it is possible to reduce the electrical resistance of the conductor connecting portion.

(j) In this embodiment, a plurality of insertion holes 212 are provided. A plurality of insertion holes 212 are provided so as not to interfere with each other. A plurality of metal strips 214 are provided so as to be inserted into the plurality of insertion holes 212 respectively. As a result, the conductive portions of the metal strip 214 with respect to the sleeve 210 and the conductor 110 can be increased. As a result, it is possible to reduce the electrical resistance of the conductor connecting portion. Also, the number of engagement points of the metal strip 214 with respect to the sleeve 210 and the conductor 110 can be increased. As a result, it is possible to improve the strength of the conductor connecting portion.

(k) In this embodiment, the insertion hole 212 penetrates from the first side wall 210a of the sleeve 210 through the conductor 110 to the second side wall 210b on the opposite side of the first side wall 210a. A metal strip 214 is inserted over the entire insertion hole 212 penetrating through them. Thereby, the metal strip 214 can be engaged with both the first side wall 210 a and the second side wall 210 b of the sleeve 210 . As a result, it is possible to increase the number of conductive points between the metal strip 214 and the sleeve 210 and reduce the electrical resistance. Further, by locking both ends of the metal strip 214 to the sleeve 210, the strength of the conductor connecting portion can be improved.

(5) Modifications of First Embodiment The above-described embodiment can be modified as in the following modifications, if necessary. Hereinafter, only elements different from the above-described embodiment will be described, and elements that are substantially the same as those described in the above-described embodiment will be given the same reference numerals, and descriptions thereof will be omitted.

In Modifications 1 to 3 below, the configurations of the insertion hole 212 and the metal strip 214 are different from those of the above embodiment.

<Modification 1>
Modification 1 of the present embodiment will be described with reference to FIG. FIG. 11 is a schematic cross-sectional view along the axial direction of a conductor showing part of the cable connection structure according to Modification 1 of the present embodiment.

As shown in FIG. 11, in this modified example, the insertion hole 212 passes through, for example, the first side wall 210a of the sleeve 210 to the conductor 110 and does not pass through the second side wall 210b on the opposite side of the first side wall 210a. .

According to Modification 1, when the metal strip 214 is inserted into the insertion hole 212, the tip of the metal strip 214 is brought into contact with the second side wall 210b of the sleeve 210, thereby restricting the progress of the metal strip 214 in the axial direction. be able to. As a result, protrusion of the metal strip 214 from the second side wall 210b of the sleeve 210 can be reliably suppressed.

<Modification 2>
Modification 2 of the present embodiment will be described with reference to FIG. FIG. 12 is a schematic cross-sectional view along the axial direction of the conductor showing part of the cable connection structure according to Modification 2 of the present embodiment.

As shown in FIG. 12, in this modified example, the insertion hole 212 is formed, for example, from the outer circumference of the sleeve 210 to a part of the conductor 110 and does not penetrate the conductor 110. As shown in FIG.

Note that the metal strip 214 preferably crosses the central axis of the conductor 110 as in the above-described embodiment.

According to Modification 2, when the metal strip 214 is inserted into the insertion hole 212, the tip of the metal strip 214 is locked by the end of the insertion hole 212 in the conductor 110 to restrict the advancement of the metal strip 214. can be done. As a result, protrusion of the metal strip 214 from the second side wall 210b of the sleeve 210 can be reliably suppressed.

<Modification 3>
Modification 3 of the present embodiment will be described with reference to FIG. FIG. 13 is an enlarged schematic view of a schematic cross-sectional view along the axial direction of the conductor showing a part of the cable connection structure according to Modification 3 of the present embodiment.

As shown in FIG. 13, in this modified example, the insertion hole 212 does not have a screw groove, for example.

The metal strip 214 is configured, for example, as a metal rod that is inserted into the insertion hole 212 . That is, the metal strip 214 does not have, for example, a thread groove on its outer circumference. The shape of the metal strip 214 is, for example, a columnar shape, and in some cases may be a polygonal columnar shape.

Since the metal strip 214 is fitted (inserted by fitting) into the insertion hole 212 as described above, the metal strip 214 can be firmly engaged with the sleeve 210 and the conductor 110 .

According to Modification 3, tapping for forming thread grooves can be omitted in the insertion hole forming step S242. Thereby, the connection work in the cable connection structure 20 can be simplified.

<Second embodiment of the present disclosure>
Next, a second embodiment of the present disclosure will be described. Hereinafter, description will be omitted as appropriate, similarly to the modified example of the above-described first embodiment.

Although the cable connection structure 20 that connects the pair of power cables 100 has been described in the above-described first embodiment, the present disclosure is not limited to this case. The configuration of the conductor connection portion described above may be applied to the cable termination connection structure 22 as in the present embodiment below.

The cable termination connection structure 22 of this embodiment will be described with reference to FIG. FIG. 14 is a schematic cross-sectional view along the axial direction of the conductor showing the cable termination connection structure according to this embodiment.

As shown in FIG. 14, the cable termination structure 22 of this embodiment is configured to terminate the power cable 100, for example. Specifically, the cable termination connection structure 22 has, for example, a power cable 100, a sleeve 210, a metal strip 214, an insulating tube 400, and a porcelain tube 300.

The power cable 100 is, for example, peeled off in stages from the tip of the conductor 110 toward the opposite side.

Metal sleeve 210 is configured, for example, to surround the tip of conductor 110 of power cable 100 . That is, the sleeve 210 has, for example, a tubular portion 216 and a rod portion 218 . The exposed portion of the conductor 110 of the power cable 100 is inserted into the hollow portion of the tubular portion 216 . The rod-shaped portion 218 is provided on the opposite side of the tubular portion 216 .

Metal strip 214 intersects, for example, tubular portion 216 of sleeve 210 .

Specifically, similarly to the above-described embodiment, the sleeve 210 and the conductor 110 have an insertion hole 212 that extends from the outer periphery of the sleeve 210 to at least a portion of the conductor 110 so as to intersect the conductor 110. . A metal strip 214 is inserted into the insertion hole 212 from the sleeve 210 to the conductor 110 to electrically connect the sleeve 210 and the conductor 110 .

Insulating tube 400 is configured to mitigate the electric field around power cable 100 . That is, the insulating tube 400 is provided so as to surround the outer periphery of the power cable 100 and is configured to alleviate the electric field around one end of the exposed cable outer semi-conductive layer 140 . Specifically, the insulating cylinder 400 has, for example, an insulator 420 and a semiconductive layer 440 . The semiconducting layer 440 forms a so-called stress cone.

The porcelain tube 300 is, for example, tubular so that the power cable 100 to which the sleeve 210 and the insulating tube 400 are attached is inserted. The porcelain pipe 300 is erected along the vertical direction. A rod-shaped portion 218 of a sleeve 210 attached to the tip of the power cable 100 is fixed to the vertical upper end of the insulator 300 . On the other hand, the opening at the vertical lower end of the porcelain pipe 300 is sealed. In this state, the insulator 300 is filled with an insulating medium 320 such as insulating oil.

According to the second embodiment, even with the cable termination connection structure 22, it is possible to obtain the same effects as in the above-described first embodiment.

<Other embodiments of the present disclosure>
Although the embodiments of the present disclosure have been specifically described above, the present disclosure is not limited to the above-described embodiments, and can be variously modified without departing from the scope of the present disclosure.

In the above-described embodiment, the conductor 110 was shown to have a cylindrical conductor strand layer 114, but the conductor 110 may be a so-called segmented conductor. That is, the conductor wire layer 114 may be, for example, an irregularly shaped layer such as a fan shape.

In the above-described embodiment, the case where the conductor strand 112 contains aluminum or an aluminum alloy and has an aluminum oxide film on the outer periphery has been described. good. That is, the conductor wire 112 may contain, for example, copper or a copper alloy and have an insulating coating on its outer periphery.

In the above-described embodiment, the case where the conductor strands 112 in both power cables 100 have an oxide coating or an insulating coating on the outer periphery has been described, but the present disclosure is not limited to this case. Conductor wire 112 in at least one of pair of power cables 100 may have an oxide coating or an insulating coating on its outer periphery. That is, in the first power cable 100 of the pair of power cables 100, the conductor strand 112 has an oxide coating or an insulation coating on the outer periphery, and in the second power cable 100, the conductor strand 112 has an oxide coating or an insulation coating. on the outer periphery. Specifically, for example, connection between an aluminum conductor and a standard copper conductor (pure copper conductor), connection between a wire insulated conductor and a standard copper conductor, and the like are conceivable.

In the above-described embodiment, the case where the conductor 110 has the water propagation suppression layer 116 interposed between the multiple conductor wire layers 114 has been described, but the present disclosure is not limited to this case. The conductor 110 may not have the water propagation suppression layer 116, and the pair of conductor wire layers 114 adjacent in the thickness direction among the plurality of conductor wire layers 114 may be in direct contact with each other. Also in this case, the metal strip 214 preferably penetrates the plurality of conductor wire layers 114 within the sleeve 210 . Thereby, the plurality of conductor wire layers 114 and the metal strips 214 can be electrically connected.

Although the application of the compound was not mentioned in the above embodiments, the application of the compound in the present disclosure is not limited. For example, a compound containing metal particles may be provided between the inner peripheral surface of the sleeve 210 and the outer peripheral surface of the conductor 110 . Thereby, the electrical resistance can be stably reduced. On the other hand, there may be no compound between the inner peripheral surface of sleeve 210 and the outer peripheral surface of conductor 110 . As a result, even if an accident current flows through the connecting power cable 10 and the connecting power cable 10 becomes hot, there is no possibility that the resin component or the oil component in the compound will vaporize.

In the above-described embodiment, the case where the cable connection structure 20 is configured as a so-called factory joint and the inner semi-conductive layer 220, the insulating layer 230 and the outer semi-conductive layer 240 are individually configured has been described. can't The inner semi-conducting layer 220, the insulating layer 230 and the outer semi-conducting layer 240 may consist of rubber blocks molded together.

In the above-described embodiment, the connection power cable 10 is configured as an underwater cable, but the connection power cable 10 may be configured to be laid underground or on the ground.

Although one cable connection structure 20 included in the coupling power cable 10 has been described in the above-described embodiment, the coupling power cable 10 may have a plurality of cable connection structures 20 .

Next, examples according to the present disclosure will be described. These examples are examples of the present disclosure, and the present disclosure is not limited by these examples.

(1) Production of connection power cables Using the following power cables, connection power cables of Examples and Comparative Examples 1 to 3 were produced.

(power cable)
Conductor material: Aluminum Conductor cross-sectional area: 2500 mm ²
Cable inner semi-conductive layer, insulating layer, outer semi-conductive layer thickness: 2mm, 19mm, 2mm

[Example]
Four cable connection structures having the following conductor connection portions were formed to produce the connection power cable of the example.

(Conductor connection part)
Sleeve material: Copper Sleeve inner diameter: 79.0mm
Sleeve length: 240mm
Insertion hole length: Through sleeve Number of insertion holes: 18 Placement of insertion holes: Spiral (non-interfering position)
Insertion hole diameter (at the time of drill hole formation): 7.5mm
Metal strip material: Copper

(connected power cable)
Axial length of power cable: 2.7m
Outer diameter of the cross section including the conductor connection part: Power cable outer diameter + 20 mm or less Arrangement of the conductor connection part: Equal intervals in the axial direction

[Comparative Example 1]
A conductor connecting portion was formed by the above-mentioned (i) method of applying a compound to the outer peripheral surface of the conductor.
Sleeve: Example sleeve without insertion holes Metal strip: None Compound: Compound applied to outer circumference of conductor (inner surface of sleeve)

[Comparative Example 2]
A conductor connecting portion was formed by the above-described method (ii) of tightening a bolt from the outer peripheral side of the sleeve.
Sleeve: specification with an insertion hole similar to the sleeve of the example Conductor connection part: Without forming an insertion hole in the conductor, the tip of the bolt was brought into contact with the conductor, and the head of the bolt was cut off.

[Comparative Example 3]
A conductor connection portion was formed by the above-described (iii) method of welding a conductor.
Sleeve: None Conductor connection: Welded

(2) Test method [heat cycle test]
Thirty cycles including a step of applying a current of up to 3000 A for 8 hours and a step of turning off the current for 16 hours were performed on the coupling power cable prepared as described above. During this time, the temperature near each conductor connection was measured with a thermocouple.

[Tensile test]
After the heat cycle test, a tensile breaking test was performed on the connecting power cable.

(3) Results [heat cycle test]
The results of the heat cycle test are compared between Comparative Examples 1 and 2 and the example.

In the connecting power cables of Comparative Examples 1 and 2 in which the bolts are in contact with the conductors, the temperature in the vicinity of the conductor connection rises to 120° C. in the initial current flow process, and then the temperature gradually decreases as the cycle is repeated. was rising to After 30 cycles, the temperature increased by about +15 to +16°C from the initial temperature.

In Comparative Examples 1 and 2, the conducting portion was limited to the contact portion of the compound or the tip of the bolt with respect to the outer peripheral surface of the conductor. In addition, it was difficult to sufficiently break the oxide film or insulation film of the conductor wire with the compound or the flat surface of the tip of the bolt. Moreover, in Comparative Example 2, there was a possibility that a gap was generated between the tip of the bolt and the conductor due to thermal expansion and thermal contraction during the heat cycle. For these reasons, in Comparative Examples 1 and 2, the electrical resistance of the conductor connection portion tends to be high. As a result, in Comparative Examples 1 and 2, it is considered that the conductor connecting portion generated abnormal heat every time the heat cycle was repeated.

On the other hand, in the connection power cable of the example having the cable connection structure according to the above-described embodiment, the temperature in the vicinity of the conductor connection portion rises to 120° C. in the process of the first current flow, and even if the subsequent cycles are repeated, , the temperature was maintained around 120°C.

In the example, it was possible to secure the conducting portion over the entire axial direction of the metal strip, and it was possible to reduce the electrical resistance of the conductor connecting portion. As a result, it was confirmed that abnormal heat generation at the conductor connecting portion could be suppressed in the example even if the heat cycle was repeated.

[Tensile test]
Comparative Example 3 and Example are compared in terms of the results of the tensile test.

In the connection power cable of Comparative Example 3 with welded conductors, the tensile breaking tension after the heat cycle test was 5.7 kgf/mm ² .

In Comparative Example 3, the mechanical strength of the welded portion was not sufficient. Therefore, the tensile breaking tension after the heat cycle test was low.

On the other hand, in the connection power cable of the example having the cable connection structure according to the embodiment described above, the tensile breaking tension after the heat cycle test was 7.7 kgf/mm ² . In normal specifications, a cable is designed with a tensile strength of 4 kgf/mm ² in consideration of safety. Therefore, in the connection power cable of the example, sufficient tensile strength (approximately double the tensile strength) can be secured. I confirmed that.

In the example, by inserting the metal strip from the sleeve to the conductor into the insertion hole, the metal strip could be engaged with both the sleeve and the conductor. As a result, it was confirmed that the strength (tensile strength) of the conductor connection portion could be improved in the example as compared with the comparative example 3.

<Preferred Embodiment of the Present Disclosure>
Preferred embodiments of the present disclosure will be added below.

(Appendix 1)
a pair of power cables each having a conductor;
a metal sleeve surrounding a connection point connecting the conductors of the pair of power cables;
a metal strip crossing the sleeve;
has
The sleeve and the conductor have an insertion hole opened from the outer periphery of the sleeve to at least a part of the conductor so as to cross the conductor,
The cable connection structure, wherein the metal strip is inserted into the insertion hole from the sleeve to the conductor to electrically connect the sleeve and the conductor.

(Appendix 2)
The cable connection structure according to appendix 1, wherein the metal strip does not protrude outside the outer circumference of the sleeve.

(Appendix 3)
The cable connection structure according to appendix 1 or appendix 2, wherein the sleeve is compressed in a radial direction of the conductor.

(Appendix 4)
The conductor in at least one of the pair of power cables has a conductor wire having an oxide coating or an insulating coating on its outer periphery,
3. The cable connection structure according to any one of appendices 1 to 3, wherein the metal strip penetrates at least part of the oxide film or the insulating film of the conductor wire.

(Appendix 5)
The conductor is
a plurality of conductor strand layers having a plurality of conductor strands;
a water propagation suppression layer that is interposed between the plurality of conductor wire layers and suppresses propagation of water in the conductor;
has
5. The cable connection structure according to any one of appendices 1 to 4, wherein the metal strip penetrates at least a portion of the water propagation suppression layer within the sleeve.

(Appendix 6)
The conductor has a plurality of conductor strand layers having a plurality of conductor strands,
a pair of conductor wire layers adjacent in the thickness direction among the plurality of conductor wire layers are in direct contact with each other;
5. The cable connection structure according to any one of appendices 1 to 4, wherein the metal strip penetrates the plurality of conductor wire layers within the sleeve.

(Appendix 7)
The insertion hole has a thread groove,
7. The cable connection structure according to any one of appendices 1 to 6, wherein the metal strip is screwed into the screw groove of the insertion hole.

(Appendix 8)
The insertion hole does not have a thread groove,
7. The cable connection structure according to any one of appendices 1 to 6, wherein the metal strip is configured as a metal rod to be inserted into the insertion hole.

(Appendix 9)
A plurality of the insertion holes are provided so as not to interfere with each other,
9. The cable connection structure according to any one of appendices 1 to 8, wherein a plurality of the metal strips are provided so as to be respectively inserted into the plurality of insertion holes.

(Appendix 10)
The cable connection structure according to appendix 9, wherein the plurality of insertion holes are spirally provided in the axial direction of the conductor.

(Appendix 11)
11. The cable connection structure according to any one of appendices 1 to 10, wherein the metal strip intersects the central axis of the conductor.

(Appendix 12)
12. The cable connection structure according to any one of appendices 1 to 11, wherein the insertion hole penetrates from the first side wall of the sleeve through the conductor to the second side wall on the opposite side of the first side wall.

(Appendix 13)
12. The cable connection structure according to any one of appendices 1 to 11, wherein the insertion hole penetrates from a first side wall of the sleeve to the conductor, and does not penetrate a second side wall opposite to the first side wall. .

(Appendix 14)
12. The cable connection structure according to any one of appendices 1 to 11, wherein the insertion hole extends from the outer circumference of the sleeve to a part of the conductor and does not penetrate the conductor.

(Appendix 15)
A coupling power cable comprising at least one cable connection structure according to any one of appendices 1 to 14.

(Appendix 16)
a power cable having a conductor;
a metal sleeve surrounding the tip of the conductor of the power cable;
a metal strip crossing the sleeve;
a porcelain tube into which the power cable to which the sleeve is attached is inserted;
has
The sleeve and the conductor have an insertion hole opened from the outer periphery of the sleeve to at least a part of the conductor so as to cross the conductor,
The cable termination connection structure, wherein the metal strip is inserted into the insertion hole from the sleeve to the conductor to electrically connect the sleeve and the conductor.

(Appendix 17)
providing a pair of power cables each having a conductor;
arranging a metal sleeve so as to surround a connection point where the conductors of the pair of power cables are connected;
intersecting a metal strip against the sleeve;
has
The step of intersecting the metal strips includes:
forming an insertion hole in the sleeve and the conductor from the outer circumference of the sleeve to at least a part of the conductor so as to intersect the conductor;
a step of inserting the metal strip into the insertion hole from the sleeve to the conductor, and electrically connecting the sleeve and the conductor by the metal strip;
A method of manufacturing a cable connection structure comprising:

(Appendix 18)
In the step of preparing the pair of power cables,
The conductor has a plurality of conductor wire layers having a plurality of conductor wire layers, and a water propagation suppression layer interposed between the plurality of conductor wire layers and suppressing propagation of water in the conductor. preparing the power cable;
In the step of opening the insertion hole,
forming the insertion hole in the sleeve and the conductor with the conductor having the water propagation suppression layer;
In the step of inserting the metal strip,
18. The method of manufacturing a cable connection structure according to appendix 17, wherein the metal strip is inserted into the insertion hole so as to penetrate at least a portion of the water propagation suppression layer within the sleeve.

(Appendix 19)
providing a power cable having a conductor;
arranging a metal sleeve to surround the tip of the conductor of the power cable;
intersecting a metal strip against the sleeve;
inserting the power cable with the sleeve attached into a porcelain pipe;
has
The step of intersecting the metal strips includes:
forming an insertion hole in the sleeve and the conductor from the outer circumference of the sleeve to at least a part of the conductor so as to intersect the conductor;
a step of inserting the metal strip into the insertion hole from the sleeve to the conductor, and electrically connecting the sleeve and the conductor by the metal strip;
A method of manufacturing a cable termination structure comprising:

10 Connecting power cable 20 Cable connection structure 22 Cable termination connection structure 100 Power cable 100a First power cable 100b Second power cable 110 Conductor 112 Conductor wire 114 Conductor wire layer 116 Water propagation suppression layer 120 Cable internal semiconductive layer 130 Cable Insulating layer 140 Cable outer semi-conductive layer 150 Cable metal shielding layer 160 Cable sheath 170 Cable outer structure 210 Sleeve 210a First side wall 210b Second side wall 212 Insertion hole 214 Metal strip 216 Cylindrical part 218 Rod-like part 219 Double nut 220 Internal semi-conductive Layer 230 Insulating layer 240 External semi-conductive layer 242 Water absorbing tape layer 250 Metal tube 260 Anti-corrosion layer 300 Porcelain tube 320 Insulating medium 400 Insulating tube 420 Insulator 440 Semi-conductive layer

Claims (16)

a pair of power cables each having a conductor;
a metal sleeve surrounding a connection point connecting the conductors of the pair of power cables;
a metal strip crossing the sleeve;
has
The sleeve and the conductor have an insertion hole opened from the outer periphery of the sleeve to at least a part of the conductor so as to cross the conductor,
The cable connection structure, wherein the metal strip is inserted into the insertion hole from the sleeve to the conductor to electrically connect the sleeve and the conductor. 2. The cable connection structure according to claim 1, wherein the metal strip does not protrude outside the outer periphery of the sleeve. 3. The cable connection structure according to claim 1, wherein said sleeve is compressed in a radial direction of said conductor. The conductor in at least one of the pair of power cables has a conductor wire having an oxide coating or an insulating coating on its outer periphery,
The cable connection structure according to any one of claims 1 to 3, wherein the metal strip penetrates at least part of the oxide coating or the insulating coating of the conductor wire. The conductor is
a plurality of conductor strand layers having a plurality of conductor strands;
a water propagation suppression layer that is interposed between the plurality of conductor wire layers and suppresses propagation of water in the conductor;
has
The cable connection structure according to any one of claims 1 to 4, wherein the metal strip penetrates at least a portion of the water propagation suppression layer within the sleeve. The conductor has a plurality of conductor strand layers having a plurality of conductor strands,
a pair of conductor wire layers adjacent in the thickness direction among the plurality of conductor wire layers are in direct contact with each other;
The cable connection structure according to any one of claims 1 to 4, wherein the metal strip penetrates the plurality of conductor wire layers within the sleeve. The insertion hole has a thread groove,
The cable connection structure according to any one of claims 1 to 6, wherein the metal strip is screwed into the screw groove of the insertion hole. The insertion hole does not have a thread groove,
The cable connection structure according to any one of claims 1 to 6, wherein the metal strip is configured as a metal rod fitted into the insertion hole. A plurality of the insertion holes are provided so as not to interfere with each other,
The cable connection structure according to any one of claims 1 to 8, wherein a plurality of said metal strips are provided so as to be respectively inserted into said plurality of insertion holes. 10. The cable connection according to any one of claims 1 to 9, wherein the insertion hole penetrates from the first side wall of the sleeve through the conductor to a second side wall opposite to the first side wall. structure. 10. The cable according to any one of claims 1 to 9, wherein the insertion hole penetrates from the first sidewall of the sleeve to the conductor and does not penetrate the second sidewall opposite to the first sidewall. connection structure. 10. The cable connection structure according to any one of claims 1 to 9, wherein the insertion hole extends from the outer circumference of the sleeve to a part of the conductor and does not penetrate the conductor. An articulated power cable comprising at least one cable connection structure according to any one of claims 1 to 12. a power cable having a conductor;
a metal sleeve surrounding the tip of the conductor of the power cable;
a metal strip crossing the sleeve;
a porcelain tube into which the power cable to which the sleeve is attached is inserted;
has
The sleeve and the conductor have an insertion hole opened from the outer periphery of the sleeve to at least a part of the conductor so as to cross the conductor,
The cable termination connection structure, wherein the metal strip is inserted into the insertion hole from the sleeve to the conductor to electrically connect the sleeve and the conductor. providing a pair of power cables each having a conductor;
arranging a metal sleeve so as to surround a connection point where the conductors of the pair of power cables are connected;
intersecting a metal strip against the sleeve;
has
The step of intersecting the metal strips includes:
forming an insertion hole in the sleeve and the conductor from the outer circumference of the sleeve to at least a part of the conductor so as to intersect the conductor;
a step of inserting the metal strip into the insertion hole from the sleeve to the conductor, and electrically connecting the sleeve and the conductor by the metal strip;
A method of manufacturing a cable connection structure comprising: providing a power cable having a conductor;
arranging a metal sleeve to surround the tip of the conductor of the power cable;
intersecting a metal strip against the sleeve;
inserting the power cable with the sleeve attached into a porcelain pipe;
has
The step of intersecting the metal strips includes:
forming an insertion hole in the sleeve and the conductor from the outer circumference of the sleeve to at least a part of the conductor so as to intersect the conductor;
a step of inserting the metal strip into the insertion hole from the sleeve to the conductor, and electrically connecting the sleeve and the conductor by the metal strip;
A method of manufacturing a cable termination structure comprising:

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