WO2020044926A1

WO2020044926A1 - Intermediate connecting structure for power cable

Info

Publication number: WO2020044926A1
Application number: PCT/JP2019/030187
Authority: WO
Inventors: 中西　辰雄
Original assignee: 住友電気工業株式会社
Priority date: 2018-08-30
Filing date: 2019-08-01
Publication date: 2020-03-05

Abstract

This intermediate connecting structure for a power cable is provided with a pair of power cables each having a tip end portion in which a cable conductor, a cable insulator, and a cable outer semiconductive layer are exposed in a stepped manner, a conductor connecting portion connecting the exposed cable conductors to one another, and a cylindrical rubber unit, wherein: each cable insulator is provided with a first inclined portion having an outer diameter which decreases toward the cable conductor side; the rubber unit is provided with a main insulating portion, an inner semiconductive portion which is provided on an inner circumferential side of the main insulating portion in an axially central portion thereof and which is disposed in such a way as to cover an outer circumference of the conductor connecting portion, and an outer semiconductive portion which is provided on the end portion sides of the main insulating portion and which is connected to the cable outer semiconductive layers; and the rubber unit is disposed in such a way as to fit into a recess formed by the conductor connecting portion and the first inclined portions.

Description

Intermediate connection structure of power cable

The present disclosure relates to an intermediate connection structure of a power cable.
This application claims priority based on Japanese Patent Application No. 2018-162191 filed on Aug. 30, 2018, and incorporates all the contents described in the Japanese application.

Patent Document 1 discloses a power cable connection unit that connects a pair of power cables each having a conductor and an insulating layer in a straight line while aligning their axes. The power cable connection unit includes a conductor connection portion, an insulating layer connection portion, and a cover member. The conductor connecting portion connects the exposed pair of conductors in the power cable. The insulating layer connection part surrounds the outer periphery of the conductor connection part and both ends extend along the axial direction, respectively, and connects the pair of insulation layers of the power cable across the conductor connection part. The cover member covers the outer periphery of the insulating layer connection portion and both ends extend in the axial direction, respectively, and integrally covers the outer periphery of the pair of insulating layers in the power cable across the insulating layer connection portion. The cover member includes a semiconductive covering layer made of a semiconductive rubber material and an insulating covering layer made of an insulating rubber material.

JP 2016-12974 A

The intermediate connection structure of the power cable according to the present disclosure,
A set of power cables having a cable conductor, a cable insulator, and a cable outer semiconductive layer having a stepwise exposed tip;
A conductor connecting portion for connecting the exposed cable conductors,
With a cylindrical rubber unit,
Each of the cable insulators includes a first inclined portion whose outer diameter decreases toward the cable conductor,
The rubber unit,
Main insulation,
An inner semiconductive portion provided on the inner peripheral side and the axial center portion of the main insulating portion, and arranged to cover the outer periphery of the conductor connecting portion,
An external semiconductive portion provided on each end side of the main insulating portion and connected to each of the cable external semiconductive layers,
It is arranged so as to fit into a depression formed by the conductor connection portion and each of the first inclined portions.

FIG. 1 is a cross-sectional view schematically illustrating a power cable intermediate connection structure according to the first embodiment. FIG. 2 is a cross-sectional view of a rubber unit provided in the power cable intermediate connection structure according to the first embodiment, showing a state before a set of power cables is attached to a set connected by a conductor connection portion. FIG. 3 is a cross-sectional view schematically illustrating an intermediate connection structure of a power cable according to the second embodiment. FIG. 4 is a cross-sectional view of a rubber unit provided in the power cable intermediate connection structure according to the second embodiment, showing a state before a set of power cables is attached to a set connected by a conductor connection portion. FIG. 5 is a cross-sectional view schematically illustrating a power cable intermediate connection structure according to the third embodiment. FIG. 6 is a cross-sectional view schematically illustrating an intermediate connection structure of a power cable according to the fourth embodiment.

[Problems to be solved by the present disclosure]
The cover member may be displaced from a predetermined position by an axial force which is an axial force applied to the power cable due to thermal expansion and contraction of the power cable. Hereinafter, the cover member is referred to as a rubber unit. In the technique of Patent Literature 1, a concave portion is provided in an insulating layer connecting portion, and a rubber unit is fitted into the concave portion, thereby suppressing a deviation of the rubber unit from a predetermined position. However, in the technique of Patent Document 1, there is a possibility that the displacement of the rubber unit from a predetermined position cannot be suppressed depending on the magnitude of the axial force of the power cable.

Therefore, the present disclosure provides a power cable intermediate connection structure that can suppress a rubber unit disposed so as to cover an outer periphery of a conductor connection portion connecting cable conductors of a set of power cables from a predetermined position. It is one of the purposes.

[Effects of the present disclosure]
The power cable intermediate connection structure according to the present disclosure can prevent a rubber unit arranged to cover an outer periphery of a conductor connection portion that connects cable conductors of a set of power cables from being shifted from a predetermined position.

[Description of Embodiment of the Present Disclosure]
First, the contents of the embodiments of the present disclosure will be listed and described.

(1) The intermediate connection structure of the power cable according to the embodiment of the present disclosure includes:
A set of power cables having a cable conductor, a cable insulator, and a cable outer semiconductive layer having a stepwise exposed tip;
A conductor connecting portion for connecting the exposed cable conductors,
With a cylindrical rubber unit,
Each of the cable insulators includes a first inclined portion whose outer diameter decreases toward the cable conductor,
The rubber unit,
Main insulation,
An inner semiconductive portion provided on the inner peripheral side and the axial center portion of the main insulating portion, and arranged to cover the outer periphery of the conductor connecting portion,
An external semiconductive portion provided on each end side of the main insulating portion and connected to each of the cable external semiconductive layers,
It is arranged so as to fit into a depression formed by the conductor connection portion and each of the first inclined portions.

では In the power cable intermediate connection structure, the rubber unit is disposed so as to fit into the recess formed by the conductor connection portion and the first inclined portion of each cable insulator. Since the recess into which the rubber unit fits is formed by the cable insulator, the recess can be formed relatively deep and over a relatively long area along the axial direction of the power cable. Therefore, the rubber unit is stably held in the recess, and in the intermediate connection structure of the power cable, even if the axial force of the power cable is large, it is possible to suppress the deviation of the rubber unit from a predetermined position.

If the cable insulator does not have a depression, that is, if the outer diameter of the cable insulator is uniform in the longitudinal direction of the power cable, the rubber unit is expanded in a state in which the diameter of the rubber unit is 1.3 to 1.4 times. It is arranged on an insulator. Therefore, a surface pressure is applied on the cable insulator by the contraction force of the rubber unit. This surface pressure is applied substantially uniformly in the longitudinal direction of the power cable. For example, when the rubber unit is made of silicone rubber, a surface pressure of 0.1 MPa or more is applied. When the rubber unit is made of ethylene propylene rubber, a surface pressure of 0.3 MPa or more is applied. On the other hand, when the cable insulator has a depression, the minimum outer diameter of the cable insulator can be reduced by about 5% from the maximum outer diameter of the cable insulator. The minimum outer diameter of the cable insulator is the outer diameter of the deepest part of the depression. The maximum outer diameter of the cable insulator is the outer diameter of a portion having no depression. By fitting the rubber unit into such a depression, the surface pressure can be increased at the portion having the maximum outer diameter as compared with the portion having the minimum outer diameter. The deviation of the rubber unit from the predetermined position can be suppressed by this surface pressure. Since the rubber unit can be held at a predetermined position, insulation at the connection portion of the power cable and a retaining force against axial force can be secured. As a result, the reliability of the connection portion can be maintained.

中間 In the above-mentioned intermediate connection structure of the power cable, there are cases where the method of processing the semiconductive layer outside the cable can be simplified.

ケーブル The cable insulator of the power cable may have uneven thickness in the circumferential direction due to eccentricity or uneven thickness due to the molding method. For this reason, the cable insulator may have an allowance in the thickness, and may have an outer diameter larger than the design insulation outer diameter which is the minimum specified outer diameter. An outer diameter larger than the designed insulation outer diameter is called a finished insulation outer diameter. Also, similarly to the cable insulator, the cable outer semiconductive layer formed on the outer periphery of the cable insulator may be eccentric or uneven in thickness, and may have a nonuniform thickness in the circumferential direction. For this reason, the cable outer semiconductive layer may have a margin in the thickness, and may have an outer diameter larger than the designed outer diameter which is the minimum specified outer diameter. An outer diameter larger than the designed outer diameter is called a finished outer diameter.

場合 When the outer diameter of the cable insulator is uniform in the axial direction at the finished insulating outer diameter, it is necessary to prepare a rubber unit having an inner diameter corresponding to the finished insulating outer diameter. Hereinafter, the inner diameter of the rubber unit may be referred to as the inner diameter of the rubber unit. When the finished insulation outer diameter varies, it is necessary to prepare rubber units having various inner diameters corresponding to each finished insulation outer diameter. On the other hand, if the rubber unit has an inner diameter of the rubber unit corresponding to the design outer diameter, electrically stable connection can be performed. In addition, if the rubber unit has a rubber unit inner diameter corresponding to the design insulation outer diameter, even if the finished insulation outer diameter of the cable insulator varies, a single rubber unit corresponding to the design insulation outer diameter Can be prepared, and the variety of rubber units can be reduced. When using a rubber unit with a rubber unit inner diameter corresponding to the design insulation outer diameter, when shaving the outer semiconductive layer of the cable with the finished outer diameter, cut the cable insulator and remove the outside of the cable insulator. It is conceivable to make the diameter uniform in the axial direction at the design insulation outer diameter. However, if the outer diameter of the cable insulator is made uniform in the axial direction at the design outer diameter, the cable insulator should be exposed more gradually when exposing the end of the power cable compared to the finished outer diameter. This is a difficult processing method for the cable external semiconductive layer provided on the outer periphery of the cable. This is because the method of treating the cable outer semiconductive layer can be simplified as the thickness of the cable insulator is larger, that is, as the outer diameter of the cable insulator is larger.

In the power cable intermediate connection structure, since the cable insulator has the first inclined portion, the outer diameter of the small diameter side of the first inclined portion is set as the design insulating outer diameter, and the outer diameter of the large diameter side of the first inclined portion. Can be the finished insulation outer diameter. Therefore, in the power cable intermediate connection structure, a rubber unit having a rubber unit inner diameter corresponding to the designed insulation outer diameter can be used. In addition, in the power cable intermediate connection structure, the method of treating the cable outer semiconductive layer can be simplified to a method corresponding to the finished insulation outer diameter. Further, in the intermediate connection structure of the power cable, since the outer diameter on the large diameter side of the first inclined portion is the finished insulation outer diameter, the thickness of the cable insulator is thicker than in the case of the design insulation outer diameter. Therefore, the electric field immediately below the cable external semiconductive layer can be reduced.

(2) As one mode of the intermediate connection structure of the power cable of the present disclosure,
Each of the exposed cable outer semiconductive layers may include a second inclined portion whose outer diameter decreases toward the distal end so as to be continuous with the first inclined portion.

備える By providing the cable outer semiconductive layer with the second inclined portion, the cable outer semiconductive layer can be processed simultaneously with the shaving process for forming the first inclined portion on the cable insulator. Therefore, in the above-mentioned intermediate connection structure of the power cable, the method of processing the semiconductive layer outside the cable can be further simplified.

(3) As one mode of the intermediate connection structure of the power cable of the present disclosure,
The internal semiconductive portion,
A base portion radially overlapping with the conductor connection portion,
Each of the bases may include a projection that projects radially inward from a region on the outer peripheral side at both ends in the axial direction of the base and that does not overlap the conductor connection part in the radial direction.

電界 In the rubber unit, the electric field tends to concentrate at both axial ends of the internal semiconductive portion. Therefore, the electric field concentration can be reduced by providing the projecting portions projecting radially inward at both axial ends of the internal semiconductive portion.

(4) As one mode of the intermediate connection structure of the power cable of the present disclosure,
The rubber unit may be composed of ethylene propylene rubber or silicone rubber.

Ethylene propylene rubber is a relatively hard rubber. Therefore, when the rubber unit is made of ethylene propylene rubber, the rubber unit can be slightly moved even after the rubber unit is mounted in the recess. Therefore, it is easy to position the rubber unit at a predetermined position. On the other hand, silicone rubber is a relatively soft rubber. Therefore, when the rubber unit is made of silicone rubber, the rubber unit can be easily fitted into the recess.

[Details of Embodiment of the Present Disclosure]
Hereinafter, embodiments of the present disclosure will be specifically described with reference to the drawings. In the drawings, the same reference numerals indicate the same names. It should be noted that the present invention is not limited to these exemplifications, but is indicated by the claims, and is intended to include all modifications within the scope and meaning equivalent to the claims.

<First embodiment>
A power cable intermediate connection structure 1A according to the first embodiment will be described with reference to FIGS. FIG. 1 is a vertical cross section of the power cable intermediate connection structure 1A cut along a plane parallel to the longitudinal direction. In FIG. 1, the inclination angle of the first inclined portion 220 provided in the cable insulator 22 of the power cable 2 is exaggerated for easy understanding. FIG. 2 is a longitudinal sectional view of the rubber unit 5A cut along a plane parallel to the longitudinal direction. The rubber unit 5A shown in FIG. 2 is in a state before the set of power cables 2 shown in FIG.

中間 Intermediate connection structure of power cable≫
〔Overview〕
The power cable intermediate connection structure 1A connects the cable conductors 21 of a set of power cables 2 to construct a power cable line. This power cable intermediate connection structure 1A includes a power cable 2, a conductor connection portion 3, and a rubber unit 5A. The power cable 2 has a distal end in which the cable conductor 21, the cable insulator 22, and the cable outer semiconductive layer 23 are stepwise exposed. The conductor connection part 3 connects the exposed cable conductors 21 to each other. The rubber unit 5 A is arranged so as to cover the outer periphery of the distal end of both power cables 2 including the conductor connection 3. In the power cable intermediate connection structure 1A according to the first embodiment, the exposed cable insulator 22 has the first inclined portion 220 whose outer diameter decreases toward the exposed cable conductor 21 side, and the rubber unit 5A Is one of the features of the present invention in that it is disposed so as to fit into a recess formed by the conductor connection portion 3 and each first inclined portion 220. Hereinafter, the configuration of the power cable intermediate connection structure 1A will be described in detail.

[Power cable]
The power cable 2 includes, in order from the center, a cable conductor 21, a cable internal semiconductive layer (not shown), a cable insulator 22, a cable external semiconductive layer 23, a cable shielding layer 24, and a sheath 25. The power cable 2 of this example is a crosslinked polyethylene insulated vinyl sheath cable called a CV cable.

構成 The constituent material of the cable conductor 21 is a metal having excellent conductivity, for example, copper, aluminum, or an alloy thereof. A constituent material of the cable insulator 22 includes a resin having excellent electric insulation. In this example, it is a crosslinked polyethylene. The constituent material of the cable external semiconductive layer 23 includes a resin having semiconductivity. The cable shielding layer 24 may be formed of a metal having excellent conductivity, for example, a tape or a braided wire made of copper, aluminum, an alloy thereof, or the like. A constituent material of the sheath 25 is a resin such as polyethylene.

は The basic configuration of the power cable 2 can refer to a known configuration. For example, the power cable 2 can be a high-voltage cable having a transmission voltage of 66 kV or more, an ultra-high-voltage cable of 400 kV or more, or even 500 kV or more.

Each power cable 2 has a distal end in which a cable conductor 21, a cable insulator 22, and a cable outer semiconductive layer 23 are gradually exposed from the distal end. The exposed cable insulator 22 has a first inclined portion 220 whose outer diameter decreases toward the exposed cable conductor 21 side. The first inclined portion 220 is formed by, for example, cutting. By having the first inclined portion 220 in the cable insulator 22, a recess is formed between the conductor connecting portion 3 described below and each of the first inclined portions 220. In this example, a sleeve cover 4 is provided on the outer periphery of the conductor connection portion 3. Therefore, the depression is formed by the conductor connection portion 3 and each first inclined portion 220 with the sleeve cover 4 interposed therebetween.

The cable insulator 22 may be uneven in thickness in the circumferential direction due to eccentricity or uneven thickness due to the molding method. For this reason, the cable insulator 22 has a thickness with a margin, and has a finished insulating outer diameter larger than the designed insulating outer diameter which is the minimum specified outer diameter. In the first inclined portion 220, the outer diameter on the smaller diameter side is the designed insulation outer diameter, and the outer diameter on the larger diameter side is the finished insulation outer diameter. The first inclined portion 220 is formed by performing a cutting process or the like on the cable insulator 22 having the finished insulating outer diameter so that the exposed cable conductor 21 has the designed insulating outer diameter.

(4) As the outer diameter of the cable insulator 22 increases, that is, as the thickness of the cable insulator 22 increases, the method of processing the cable outer semiconductive layer 23 provided on the outer periphery of the cable insulator 22 can be simplified. The method of processing the cable outer semiconductive layer 23 is determined according to the outer diameter of the cable insulator 22. For example, when the outer diameter of the cable insulator 22 is 122 mm to 124 mm, the A method requiring a certain level of skill has been established. When the outer diameter of the cable insulator 22 is 126 mm to 128 mm, the B method that can be performed with a simple skill has been established. The B method is a simple processing method in that the material is uniformly heated and pressed when the cable outer semiconductive layer 23 is reformed as compared with the A method. The outer diameter on the smaller diameter side of the first inclined portion 220 is the design insulation outer diameter, and the outer diameter on the larger diameter side is the finished insulation outer diameter, so that the outer diameter of the cable insulator 22 is the design insulation outer diameter. The processing method of the cable outer semiconductive layer 23 can be simplified as compared with a uniform case. If the finished insulating outer diameter is larger than the designed insulating outer diameter by 3% or more, there is a tendency that the processing method of the cable outer semiconductive layer 23 can be simplified. The design insulation outer diameter is 114 mm or more and 116 mm or less, and 120 mm or more and 122 mm or less when it is larger. On the other hand, the finished insulating outer diameter may be 122 mm or more and 124 mm or less, and may be 126 mm or more and 128 mm or less when larger.

In this example, the cable insulator 22 has a design insulation outer diameter on the small diameter side of the first inclined portion 220, and extends along the axial direction of the power cable 2 continuously to the first inclined portion 220. A flat portion 221 is provided. The rubber unit 5A described later is arranged such that both ends of the internal semiconductive portion 52 do not overlap the first inclined portion 220 in the radial direction. Although details will be described later, the electric field at both ends of the internal semiconductive portion 52 can be reduced by preventing the both ends of the internal semiconductive portion 52 from overlapping the first inclined portion 220 in the radial direction. In this example, the rubber unit 5A is arranged such that both ends of the internal semiconductive portion 52 are located radially outward of the small-diameter side flat portion 221. The cable insulator 22 may not have the narrow flat portion 221 and may be continuously inclined from the exposed end on the cable conductor 21 side to the end on the cable external semiconductive layer 23 side.

凹部 A concave portion 223 is formed in the small-diameter side flat portion 221 in this example along the circumferential direction of the cable insulator 22. A hook 42 of the sleeve cover 4 described later fits into the recess 223. The concave portion 223 may be provided continuously over the entire circumference of the cable insulator 22 or may be provided intermittently at an appropriate position. At the end of the small-diameter side flat portion 221 in this example, a flat portion having a smaller diameter is provided. This flat portion has an outer diameter larger than the outer diameter of the bottom surface of the concave portion 223 and smaller than the outer diameter of the smaller-diameter flat portion 221. With this flat portion, the outer peripheral surface of the small-diameter side flat portion 221 and the outer peripheral surface of the sleeve cover 4 are flush with each other when the hook portion 42 is fitted in the concave portion 223.

The first inclined portion 220 may have an inclination angle of 3 ° or more and 10 ° or less with respect to the axial direction of the power cable 2 depending on the size and voltage of the power cable 2. When the inclination angle of the first inclined portion 220 is 3 ° or more, the diameter difference between the outer diameter on the small diameter side and the outer diameter on the large diameter side of the first inclined portion 220 can be increased. As a result, the depth of the depression formed by the conductor connection portion 3 and each of the first inclined portions 220 can be made relatively large. Since the depth of the depression is deep, the rubber unit 5A can be easily fitted in the depression stably. Therefore, the retaining force against the axial force of the power cable 2 can be easily improved. Further, the outer diameter on the large diameter side can be made larger than the outer diameter on the small diameter side of the first inclined portion 220. Therefore, the processing method of the cable outer semiconductive layer 23 can be easily simplified. On the other hand, since the inclination angle of the first inclined portion 220 is equal to or less than 10 °, even after the rubber unit 5A is mounted in the recess formed by the conductor connection portion 3 and each first inclined portion 220, The unit 5A can be slightly moved. Therefore, it is easy to position the rubber unit 5A at a predetermined position. Further, at the time of power transmission of the power cable 2, when the cable insulator 22 thermally expands or contracts due to energization, the rubber unit 5A easily follows. The inclination angle of the first inclined portion 220 is more preferably 4 ° to 9 °, 5 ° to 8 °, particularly 6 ° to 8 °.

The length of the first inclined portion 220 along the axial direction of the power cable 2 is 200 mm or more and 400 mm or less, depending on the size and voltage of the power cable 2. When the length of the first inclined portion 220 along the axial direction of the power cable 2 is 200 mm or more, a depression can be formed in a relatively long region along the axial direction of the power cable 2. Further, even when the inclination angle of the first inclined portion 220 is small, the diameter difference between the outer diameter on the small diameter side and the outer diameter on the large diameter side of the first inclined portion 220 can be increased. As a result, the depth of the depression formed by the conductor connection portion 3 and each of the first inclined portions 220 can be made relatively large. Since the length of the depression along the power cable 2 is long and the depth is deep, the rubber unit 5A can be easily stably fitted into the depression. Therefore, the retaining force against the axial force of the power cable 2 can be easily improved. Further, the outer diameter on the large diameter side can be made larger than the outer diameter on the small diameter side of the first inclined portion 220. Therefore, the processing method of the cable outer semiconductive layer 23 can be easily simplified. On the other hand, when the length of the first inclined portion 220 along the axial direction of the power cable 2 is 400 mm or less, the enlargement of the connection portion of the power cable 2 can be suppressed. The length of the first inclined portion 220 along the axial direction of the power cable 2 may be 220 mm or more and 380 mm or less, particularly 250 mm or more and 350 mm or less.

(Conductor connection)
The conductor connection part 3 is a member that connects the exposed cable conductors 21 at the end of the power cable 2. The conductor connection part 3 of this example is a cylindrical member provided with blind holes that open on each end face. Each blind hole is a storage hole into which the tip of the cable conductor 21 of the power cable 2 is inserted. By performing compression connection in a state where each cable conductor 21 is inserted into each storage hole, the conductor connection portion 3 electrically connects the cable conductors 21 to each other. The constituent material of the conductor connection portion 3 includes a metal having excellent conductivity and compressibility, for example, copper, aluminum, and an alloy thereof.

[Sleeve cover]
In this example, the power cable intermediate connection structure 1 A includes a sleeve cover 4 that covers the outer periphery of the conductor connection portion 3. The sleeve cover 4 is a cylindrical member that is disposed across the conductor connection portion 3 and that connects regions on the small-diameter side of the first inclined portion 220 in the cable insulator 22. The sleeve cover 4 is configured as a cylindrical member by combining a plurality of divided pieces whose circumferential direction is divided.

スリーブ The sleeve cover 4 of this example includes a main body 41 disposed along the axial direction of the conductor connection portion 3, and hooks 42 protruding radially inward at both ends of the main body 41. The hook portion 42 has a shape corresponding to the concave portion 223 formed in the cable insulator 22 and is locked in the concave portion 223. Further, the sleeve cover 4 includes an annular groove 43 inside the hook portion 42 in the axial direction. The groove 43 is engaged with a flat portion formed at the end of the small-diameter side flat portion 221. By connecting the cable insulators 22 with the sleeve cover 4, it is possible to suppress the cable insulator 22, that is, the power cable 2 from moving in the axial direction. At this time, when the outer diameter of the sleeve cover 4 is uniform in the axial direction, the space between the cable insulators 22 becomes substantially flat, and the rubber unit 5A is easily arranged on the outer periphery of the conductor connection portion 3 via the sleeve cover 4. Examples of a constituent material of the sleeve cover 4 include a metal material such as aluminum or an alloy thereof, and a nonmetallic conductive material such as carbon.

では In this example, a gap is formed between the cable insulator 22 and the conductor connection portion 3, and a semiconductive tape layer or the like is provided in the gap. In this example, the sleeve cover 4 is provided. However, instead of the sleeve cover 4, a semiconductive tape layer can be provided from the gap between the cable insulator 22 and the conductor connection portion 3 to the outer periphery of the conductor connection portion 3. .

[Rubber unit]
The rubber unit 5A is a cylindrical member used for main insulation of the power cable intermediate connection structure 1A. The rubber unit 5 A includes a main insulating portion 51, a cylindrical internal semiconductive portion 52 provided on an inner peripheral side and an axial center portion of the main insulating portion 51, and an external provided on each end side of the main insulating portion 51. And a semiconductive portion 53. The external semiconductive portion 53 of this example is provided so as to cover the end face and the outer periphery of the main insulating portion 51 from one end to the other end of the main insulating portion 51. That is, the external semiconductive portion 53 has a cylindrical shape having both end surfaces. The external semiconductive portion includes an end external semiconductive portion provided at each end of the main insulating portion, and an outer peripheral semiconductive portion provided at an outer peripheral portion of the main insulating portion. The portion and the outer peripheral semiconductive portion may be electrically separated by the main insulating portion.

The rubber unit 5A is, as shown in FIG. 2, a molded product in which a main insulating portion 51, an inner semiconductive portion 52, and an outer semiconductive portion 53 are integrally formed. Since the main insulating part 51, the inner semiconductive part 52, and the outer semiconductive part 53 are integrally formed, the quality control of the rubber unit 5A can be performed at the factory. Therefore, the quality of the power cable intermediate connection structure 1A can be improved. Further, since the main insulating portion 51, the inner semiconductive portion 52, and the outer semiconductive portion 53 are integrally formed, the rubber unit 5A can be easily attached at the time of assembling the intermediate connection structure 1A of the power cable. .

The rubber unit 5 A is configured such that, when one set of power cables 2 is attached to a set connected by the conductor connection portion 3, the outer circumference of the cable outer semi-conductive layer 23 of one power cable 2 starts from the outer circumference of the sleeve cover 4. , A region covering the outer periphery of the cable outer semiconductive layer 23 of the other power cable 2 is continuously covered.

The inner semiconductive portion 52 is arranged so as to cover the outer periphery of the conductor connection portion 3. The internal semiconductive portion 52 is connected to the conductor connecting portion 3 via the sleeve cover 4 and has the same potential as the cable conductor 21. That is, the internal semiconductive portion 52 has a high potential. The inner semiconductive portion 52 is provided such that both ends do not overlap the first inclined portion 220 of the cable insulator 22 in the radial direction. When both ends of the inner semiconductive portion 52 radially overlap the first inclined portion 220, both ends of the inner semiconductive portion 52 face radially outward along the inclination of the first inclined portion 220, and This is because the electric field concentrates on both ends of the semiconductive portion 52. It is preferable that both end portions of the inner semiconductive portion 52 are oriented in a direction along the axial direction of the rubber unit 5A or in a direction inward in the radial direction.

In this example, the inner semiconductive portion 52 includes a base portion 521 that radially overlaps with the conductor connection portion 3 and a protrusion 522 that does not overlap with the conductor connection portion 3 in the radial direction. The protruding portions 522 protrude from regions on the outer peripheral side at both ends in the axial direction of the base portion 521, respectively. By providing the protruding portion 522 on the inner semiconductive portion 52, it is possible to prevent equipotential lines from going from the end of the inner semiconductive portion 52 to the cut end surface side of the cable insulator 22. The protruding portion 522 protrudes in the axial direction from a region on the outer peripheral side of the base portion 521, and is arranged with a part of the main insulating portion 51 interposed between the protruding portion 522 and the cable insulator 22. The rubber unit 5A is arranged such that the protruding portion 522 of the inner semiconductive portion 52 does not overlap the first inclined portion 220 of the cable insulator 22 in the radial direction. In this example, the rubber unit 5A is arranged such that the protruding portion 522 of the inner semiconductive portion 52 is located radially outward of the small-diameter side flat portion 221 of the cable insulator 22. By doing so, the protruding direction of the protruding portion 522 becomes a direction along the axial direction of the rubber unit 5A.

(4) Each external semiconductive portion 53 comes into contact with each cable external semiconductive layer 23 to be at the ground potential. That is, each external semiconductive portion 53 has a low potential. The main insulating portion 51 located between the inner semiconductive portion 52 and each outer semiconductive portion 53 contacts each cable insulator 22.

(5) The rubber unit 5A closely adheres to each power cable 2 and the conductor connection portion 3 via the sleeve cover 4 with a predetermined surface pressure. In the power cable intermediate connection structure 1 A according to the first embodiment, a depression is formed by the first inclined portion 220 of the cable insulator 22 and the sleeve cover 4. For this reason, the area on the inner peripheral side of the rubber unit 5A is fitted into the depression and arranged.

Before the rubber unit 5A is attached to the set connected by the conductor connection part 3, the inner diameter of the rubber unit 5A is substantially uniform along the axial direction, as shown in FIG. The outer diameter of the central portion is substantially uniform along the axial direction. The inner diameter of the rubber unit 5A before being attached to the above-described braid is an inner diameter corresponding to the designed insulation outer diameter of the cable insulator 22, and is slightly smaller than the outer diameter of the sleeve cover 4 in the braid. Since the rubber unit 5A has a rubber unit inner diameter corresponding to the designed insulating outer diameter, a unit having a single size can be used even when the finished insulating outer diameter of the cable insulator 22 varies. The rubber unit 5A is expanded in diameter and mounted on the above assembly.

(5) When the rubber unit 5A is mounted on the braid, the rubber unit 5A is fitted and disposed in the recess. Specifically, as shown in FIG. 1, the rubber unit 5A is located outside the recess so that the external semiconductive portions 53 at both ends of the rubber unit 5A are in contact with the cable external semiconductive layer 23. The semiconductive portion 52 is arranged so as to be located at the deepest portion of the depression. For this reason, after the rubber unit 5A is mounted on the above-mentioned braid, a dent is formed on the outer surface of the central portion in the axial direction along the dent.

Before the rubber unit 5A is mounted on the above-mentioned braid, the inner diameter is substantially uniform along the axial direction. Therefore, in the rubber unit 5A after being mounted on the above-described assembly, the diameter of the inner semiconductive portion 52 is relatively small and the diameter of the outer semiconductive portion 53 is relatively large. Therefore, in the rubber unit 5A, the surface pressure applied to the sleeve cover 4 is relatively small, and the surface pressure applied to the cable external semiconductive layer 23 is relatively large.

構成 As a constituent material of the main insulating portion 51, a rubber having an electric insulating property, for example, an insulating ethylene propylene rubber, an insulating silicone rubber, or the like can be given. The constituent material of the inner semiconductive portion 52 and the outer semiconductive portion 53 includes rubber having semiconductivity, for example, semiconductive ethylene propylene rubber and semiconductive silicone rubber. When the rubber unit 5A is made of ethylene propylene rubber, the rubber unit 5A can be slightly moved while the rubber unit 5A is fitted in the recess. Therefore, the rubber unit 5A can be easily positioned at a predetermined position even after being mounted on the above-described assembly.

組立 Method of assembling power cable intermediate connection structure≪
The power cable intermediate connection structure 1A typically includes a step of forming the first inclined portion 220 in the cable insulator 22 of the power cable 2, a step of mounting the conductor connection section 3, and a step of mounting the rubber unit 5A. Assembled through the process. In this example, a step of mounting the sleeve cover 4 is further performed.

Prepare a power cable 2 in which the outer diameter of the cable insulator 22 is a finished insulating outer diameter that is uniform in the axial direction. The finished insulating outer diameter is, for example, an outer diameter larger than the designed insulating outer diameter by 3% or more. The end of the prepared power cable 2 is peeled off stepwise, so that the cable conductor 21, the cable insulator 22, and the cable outer semiconductive layer 23 are exposed stepwise. The cable insulator 22 is formed with a first inclined portion 220 whose outer diameter decreases toward the exposed cable conductor 21 by, for example, cutting. At this time, the outer diameter on the large diameter side of the first inclined portion 220 is the finished insulation outer diameter, and the outer diameter on the small diameter side is the design insulation outer diameter. The length and the inclination angle of the first inclined portion 220 along the axial direction of the power cable 2 may be processed so that the desired length and the inclination angle are obtained. In addition, on the cable insulator 22, simultaneously with the formation of the first inclined portion 220, a small-diameter side flat portion 221 and a concave portion 223 are also formed.

(4) Each of the exposed cable conductors 21 is inserted into a storage hole of the conductor connection portion 3 and compressed, thereby connecting the cable conductors 21 to each other. At this time, before each cable conductor 21 is inserted into the storage hole of the conductor connection portion 3, the rubber unit 5A is powered by a diameter-expanding jig or an inner spiral core or the like in a state where the diameter is expanded. Insert the cable 2 and release it.

(4) The exposed portions of the cable insulator 22 on the small-diameter side of the first inclined portion 220 are connected by the sleeve cover 4. In this example, the hooks 42 of the divided pieces constituting the sleeve cover 4 are engaged with the concave portions 223 formed in the cable insulator 22, and the divided pieces are assembled into a cylindrical shape.

(4) When the sleeve cover 4 is disposed across the conductor connection portion 3, the rubber unit 5A in the expanded state is moved to a predetermined position, and then the expanded holding material is removed. As a result, the rubber unit 5A shrinks and is fitted into the recess formed by the first inclined portion 220 of each cable insulator 22 and the sleeve cover 4 to be disposed, so that the cable insulator 22, the cable outer semiconductive layer 23 And the sleeve cover 4.

≪Application≫
The power cable intermediate connection structure 1A according to the first embodiment can be suitably used as a connection point between the power cables 2 in various power cable lines for underground power transmission and the like. If the power cable intermediate connection structure 1A is laid underground, it is installed in a manhole, a cave, or the like.

≪Effect≫
The intermediate connection structure 1A of the power cable according to the first embodiment is a molded product in which the rubber unit 5A is integrally formed with the main insulating portion 51, the inner semiconductive portion 52, and the outer semiconductive portion 53. Therefore, the quality control of the rubber unit 5A can be performed at the factory, and the rubber unit 5A can be easily mounted on site.

In the power cable intermediate connection structure 1 A, the rubber unit 5 A is disposed so as to fit into a recess formed by the conductor connection portion 3 and the first inclined portion 220 of each cable insulator 22. Therefore, the rubber unit 5A is stably held in the depression, and the retaining force against the axial force of the power cable 2 can be improved. Such a power cable intermediate connection structure 1A can suppress the deviation of the rubber unit 5A from a predetermined position even when the power cable 2 has a large axial force. Since the rubber unit 5A can be held at a predetermined position, insulation and water resistance at the connection portion of the power cable 2 can be ensured. Therefore, the reliability of the connection portion can be maintained. When the rubber unit 5A is made of ethylene propylene rubber, the rubber unit 5A can be slightly moved even after the rubber unit 5A is mounted in the recess. Therefore, it is easy to position the rubber unit 5A at a predetermined position. In other words, the power cable intermediate connection structure 1A easily aligns the rubber unit 5A at a predetermined position, and after the alignment, the rubber unit 5A does not easily move in the axial direction with respect to the power cable 2.

The intermediate connection structure 1A of the power cable uses the power cable 2 having the cable insulator 22 having a finished insulation outer diameter larger than the design insulation outer diameter, so that the tip end of the power cable 2 is exposed stepwise. In addition, the processing method for the cable outer semiconductive layer 23 can be simplified. Specifically, by using a power cable 2 having a cable insulator 22 having a finished insulation outer diameter that is 3% or more larger than a designed insulation outer diameter, a method of treating the cable outer semiconductive layer 23 can be simplified. This is because the method of processing the cable outer semiconductive layer 23 can be simplified as the thickness of the cable insulator 22 is larger, that is, as the outer diameter of the cable insulator 22 is larger. On the other hand, in the power cable intermediate connection structure 1A, since the cable insulator 22 includes the first inclined portion 220, the outer diameter of the first inclined portion 220 on the smaller diameter side can be set as the design insulation outer diameter. As a result, a rubber unit 5A having a rubber unit inner diameter corresponding to the designed insulating outer diameter can be used regardless of the finished insulating outer diameter. As described above, in the power cable intermediate connection structure 1A, the rubber unit 5A having the rubber unit inner diameter corresponding to the designed insulation outer diameter can be used, and the method of treating the cable outer semiconductive layer 23 can be simplified.

In addition, the power cable intermediate connection structure 1A has a thickness of the cable insulator 22 which is larger than that of the design insulation outer diameter because the outer diameter on the large diameter side of the first inclined portion 220 is the finished insulation outer diameter. And the electric field directly below the cable external semiconductive layer 23 can be reduced.

<Embodiment 2>
A power cable intermediate connection structure 1B according to a second embodiment will be described with reference to FIGS. FIG. 3 is a vertical cross section of the power cable intermediate connection structure 1B cut along a plane parallel to the longitudinal direction. FIG. 4 is a longitudinal sectional view of the rubber unit 5B cut along a plane parallel to the longitudinal direction. The rubber unit 5B shown in FIG. 4 is in a state before the set of power cables 2 shown in FIG. 3 and 4, components having the same functions as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment. The power cable intermediate connection structure 1B according to the second embodiment differs from the power cable intermediate connection structure 1A according to the first embodiment in the shape of the rubber unit 5B. Hereinafter, the present embodiment will be described focusing on differences from the first embodiment.

Before the rubber unit 5B of this example is mounted on a set connected by the conductor connection part 3 to the power cable 2 as shown in FIG. A bulging portion 54 bulging toward the center is provided. The bulging portion 54 has a surface corresponding to a depression formed by the sleeve cover 4 shown in FIG. 3 and the first inclined portion 220 of each cable insulator 22. That is, the inner diameter of the bulging portion 54 at the central portion in the axial direction is uniform in the axial direction. The inner diameter of the inclined portion extending from the central portion of the bulging portion 54 to both ends increases toward the both ends. The inner diameter of the bulging portion 54 at the central portion in the axial direction is an inner diameter corresponding to the designed insulating outer diameter of the cable insulator 22. In this example, the inner diameter of both ends of the rubber unit 5B is an inner diameter corresponding to the finished insulating outer diameter of the cable insulator 22. The inner diameters of the central portion, the inclined portion, and both ends of the rubber unit 5B are slightly smaller than the outer diameter of the sleeve cover 4 in the braid, the outer diameter of the first inclined portion 220, and the finished insulating outer diameter of the cable insulator 22. small. The internal semiconductive portion 52 is provided in a uniform inner diameter region of the bulging portion 54. The outer diameter of the rubber unit 5B at the central portion in the axial direction is substantially uniform along the axial direction.

When the rubber unit 5B is mounted on the above-described assembly, the bulge portion 54 is fitted and disposed in a depression formed by the first inclined portion 220 of the cable insulator 22 and the sleeve cover 4. As shown in FIG. 3, the rubber unit 5B is located outside the recess so that the outer semiconductive portions 53 at both ends of the rubber unit 5B are in contact with the cable outer semiconductive layer 23. It is arranged to be located at the deepest part of the depression. Since the rubber unit 5B has the bulging portion 54 on the inner peripheral surface thereof, the outer diameter of the central portion in the axial direction remains substantially uniform even after the rubber unit 5B is mounted on the braid.

The rubber unit 5B has an inner diameter along the sleeve cover 4, each cable insulator 22, and each cable outer semiconductive layer 23 shown in FIG. Therefore, after being mounted on the above-described assembly, the diameter of the inner semiconductive portion 52 and the diameter of the outer semiconductive portion 53 are substantially equal. Therefore, in the rubber unit 5B, the surface pressure applied to the conductor connection portion 3 via the sleeve cover 4 is substantially equal to the surface pressure applied to the cable external semiconductive layer 23.

The intermediate connection structure 1B for a power cable according to the second embodiment includes, similarly to the first embodiment, a process of forming the first inclined portion 220 in the cable insulator 22 of the power cable 2 and a process of mounting the conductor connection portion 3. And the process of mounting the sleeve cover 4 and the process of mounting the rubber unit 5B. Since the rubber unit 5B of this example includes the bulging portion 54 on the inner peripheral side, as a diameter-expanding jig for expanding the diameter of the rubber unit 5B, for example, the position where the bulging portion 54 bulges most, that is, the axial center of the rubber unit 5B The use of a pair of diameter-expanding jigs that can be extracted at both ends with the position as a boundary may be used.

In the power cable intermediate connection structure 1B according to the second embodiment, as in the first embodiment, the rubber unit 5B fits into the depression formed by the conductor connection portion 3 and the first inclined portion 220 of each cable insulator 22. It is arranged to be included. Therefore, the rubber unit 5B is stably held in the depression, and the retaining force against the axial force of the power cable 2 can be improved. Therefore, even if the power cable 2 has a large axial force, the power cable intermediate connection structure 1B can suppress the rubber unit 5B from being shifted from a predetermined position. In the power cable intermediate connection structure 1B, the outer diameter on the small diameter side of the first inclined portion 220 is set as the design insulation outer diameter, and the outer diameter on the large diameter side is set as the finished insulation outer diameter. For this reason, the power cable intermediate connection structure 1B can use the rubber unit 5B having the rubber unit inner diameter corresponding to the design insulation outer diameter, and can simplify the processing method of the cable outer semiconductive layer 23. In addition, since the rubber unit 5B includes the bulge portion 54 having an inner peripheral surface corresponding to the depression on the inner peripheral side, the rubber unit 5B is substantially uniform along the axial direction of the power cable 2 in a state where the rubber unit 5B is mounted in the depression. Surface pressure can be given.

<Embodiment 3>
A power cable intermediate connection structure 1C according to a third embodiment will be described with reference to FIG. FIG. 5 is a vertical cross section of the power cable intermediate connection structure 1C cut along a plane parallel to the longitudinal direction. In FIG. 5, components having the same functions as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment. The power cable intermediate connection structure 1C according to the first embodiment is different from the power cable 2 in that an exposed cable outer semiconductive layer 23 of the power cable 2 includes a second inclined portion 230. And different. Hereinafter, the present embodiment will be described focusing on differences from the first embodiment.

The power cable 2 of this example has a second inclined portion 230 in which the outer diameter decreases toward the distal end side so as to be continuous with the first inclined portion 220 formed in the cable insulator 22 on the exposed cable outer semiconductive layer 23. Is provided. The second inclined portion 230 is formed simultaneously with the formation of the first inclined portion 220 by, for example, cutting of the cable insulator 22 and cutting of the cable outer semiconductive layer 23.

傾斜 The inclination angle of the second inclined part 230 is substantially the same as the inclination angle of the first inclined part 220. The length of the second inclined portion 230 along the axial direction of the power cable 2 is 30 mm or more, depending on the size and voltage of the power cable 2. When the length of the second inclined portion 230 along the axial direction of the power cable 2 is 30 mm or more, the processing method of the cable external semiconductive layer 23 can be further simplified. The length of the second inclined portion 230 along the axial direction of the power cable 2 may be 40 mm or more. On the other hand, when the length of the second inclined portion 230 along the axial direction of the power cable 2 is 80 mm or less, it is possible to suppress an increase in the size of the connection portion of the power cable 2. The length of the second inclined portion 230 along the axial direction of the power cable 2 may be 60 mm or less. The length along the axial direction of the power cable 2 in the second inclined portion 230 is 30 mm or more and 80 mm or less, and more preferably 40 mm or more and 60 mm.

中間 The power cable intermediate connection structure 1C according to the third embodiment has the effect of the power cable intermediate connection structure 1A according to the first embodiment. In addition, the first inclined portion 220 and the second inclined portion 230 can be easily formed by copying and shaping the distal end portion of the power cable 2, and the processing method of the cable external semiconductive layer 23 can be further simplified. In addition, since the cable insulator 22 and the cable external semiconductive layer 23 have the continuous

inclined portions

220 and 230, a step is hardly formed between the cable insulator 22 and the cable external semiconductive layer 23. Therefore, the rubber unit 5A is easily brought into close contact with the power cable 2.

<Embodiment 4>
A power cable intermediate connection structure 1D according to a fourth embodiment will be described with reference to FIG. FIG. 6 is a vertical cross section of the power cable intermediate connection structure 1D cut along a plane parallel to the longitudinal direction. In FIG. 6, components having the same functions as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment. The power cable intermediate connection structure 1D according to the fourth embodiment is different from the power cable intermediate connection according to the first embodiment in that the protrusion 522 of the inner semiconductive portion 52 of the rubber unit 5A protrudes radially inward. Different from structure 1A. Hereinafter, the present embodiment will be described focusing on differences from the first embodiment.

電力 The power cable 2 of this example includes a concave portion 224 in the exposed cable insulator 22. The recess 224 corresponds to the protruding portion 522 of the internal semiconductive portion 52 in the rubber unit 5A when the rubber unit 5A is mounted on a set to which a pair of power cables 2 are connected by the conductor connection unit 3. Position. Specifically, the depression 224 is provided radially inward of the tip of the protrusion 522. In this example, the concave portion 224 has a rear end side inclined surface continuous with the first inclined portion 220, a bottom surface substantially along the axial direction of the power cable 2, and a diameter increasing toward the exposed cable conductor 21 side. And a slope on the tip side. The tip-side inclined surface is connected to the small-diameter-side flat portion 221 of the cable insulator 22. The recess 224 is provided continuously over the entire circumference of the cable insulator 22.

Before the rubber unit 5A of this example is attached to the above-described assembly, as described in the first embodiment with reference to FIG. 2, the rubber unit 5A is uniformly arranged in the axial direction corresponding to the design insulation outer diameter of the cable insulator 22. The outer diameter of the central portion is substantially uniform along the axial direction. When the rubber unit 5 A is mounted on the above-described assembly, the rubber unit 5 A is disposed so as to fit into a recess formed by the first inclined portion 220 of the cable insulator 22 and the sleeve cover 4. At this time, since the recess 224 is formed in the cable insulator 22, a part of the rubber unit 5 A is disposed so as to fit into the recess 224. The recess 224 is provided at a position corresponding to the protruding portion 522 of the internal semiconductive portion 52 in the rubber unit 5A. Therefore, as the rubber unit 5A fits into the recess 224, the tip of the protrusion 522 is pulled radially inward and displaced. Specifically, the protrusion 522 is displaced so that both the inner peripheral surface and the outer peripheral surface are directed radially inward. Due to the displacement of the protruding portion 522, the protruding portion 522 of the inner semiconductive portion 52 protrudes radially inward when the rubber unit 5A is mounted on the above-described assembly.

では In this example, it is preferable that the rubber unit 5A is made of silicone rubber. Since silicone rubber is a relatively soft rubber, when the rubber unit 5A is attached to the above-described assembly, the rubber unit 5A is easily fitted into the recess 224.

中間 The power cable intermediate connection structure 1D according to the fourth embodiment can reduce the electric field concentration near the protrusion 522 of the rubber unit 5A, in addition to the effect of the power cable intermediate connection structure 1A according to the first embodiment. That is, the rubber unit 5A is provided with the protruding portions 522 that are directed radially inward at both axial end portions of the internal semiconductive portion 52, although electric fields are easily concentrated at both axial end portions of the internal semiconductive portion 52. This makes it possible to make the inclination or bending state of the equipotential line from the cable conductor 21 to the protruding portion 522 of the internal semiconductive portion 52 more gradual. The protruding portions 522 that are directed radially inward at both axial ends of the inner semiconductive portion 52 are formed on the inner semiconductive portion 52 itself before being mounted on the above-described assembly. Can be easily formed by providing the recessed portion 224 in the cable insulator 22 without providing the same. If the concave portion 224 is provided in the cable insulator 22, the rubber unit 5B having the bulging portion 54 on the inner peripheral surface as described in the second embodiment can be used as the rubber unit.

(4) The protruding portion of the rubber unit, which is directed inward in the radial direction, may be provided on the rubber unit itself before the rubber unit is mounted. In this case, when the rubber unit is molded, the inner peripheral surface and the outer peripheral surface of the protruding portion may be formed so as to be inclined radially inward toward both ends. If the rubber unit itself is provided with the protruding portion, it is not necessary to form a recess in the cable insulator 22. When the above-mentioned protrusion is provided on the rubber unit itself, the rubber unit is preferably made of ethylene propylene rubber for both the main insulating part and the internal semiconductive part.

Reference Signs List

1A, 1B, 1C, 1D Power cable intermediate connection structure 2 Power cable 21 Cable conductor 22 Cable insulator 220 First inclined portion 221 Small-diameter side flat portion 223 Concave portion 224 Depressed portion 23 Cable external semiconductive layer 230 Second inclined portion 24 Cable shielding layer 25 Sheath 3 Conductor connection part 4 Sleeve cover 41 Body part 42 Hook part 43

Groove part

5A, 5B Rubber unit 51 Main insulating part 52 Internal semiconductive part 521 Base part 522 Projection part 53 External semiconductive part 54 Swelling part

Claims

A set of power cables having a cable conductor, a cable insulator, and a cable outer semiconductive layer having a stepwise exposed tip;
A conductor connecting portion for connecting the exposed cable conductors,
With a cylindrical rubber unit,
Each of the cable insulators includes a first inclined portion whose outer diameter decreases toward the cable conductor,
The rubber unit,
Main insulation,
An inner semiconductive portion provided on the inner peripheral side and the axial center portion of the main insulating portion, and arranged to cover the outer periphery of the conductor connecting portion,
An external semiconductive portion provided on each end side of the main insulating portion and connected to each of the cable external semiconductive layers,
It is arranged to fit into the recess formed by the conductor connection portion and each of the first inclined portions,
Intermediate connection structure for power cables.
2. The intermediate connection structure for a power cable according to claim 1, wherein each of the exposed cable outer semiconductive layers includes a second inclined portion whose outer diameter decreases toward the distal end so as to be continuous with the first inclined portion.
The internal semiconductive portion,
A base portion radially overlapping with the conductor connection portion,
The projecting part according to claim 1 or 2, further comprising a projecting part that projects radially inward from regions on the outer peripheral side at both ends in the axial direction of the base, and that does not overlap with the conductor connection part in the radial direction. Intermediate connection structure for power cables.
The intermediate connection structure for a power cable according to any one of claims 1 to 3, wherein the rubber unit is made of ethylene propylene rubber or silicone rubber.