JP2017158236A - Power cable splicing part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power cable splicing part having a high waterproof performance even when polyethylene is used as a sheath of the power cable and a protective tube of an intermediate splicing part.SOLUTION: An intermediate splicing part 1 comprises: adhesives 202, 203, 212 and 213 applied to a surface of an outer protective tube 40 made of HDPE (High Density Polyethylene) in an end of the outer protective tube 40 and surfaces of cable sheaths 115 and 125 made of HDPE; and self-bonding rubbers 204 and 214 provided to cover the adhesives 202, 203, 212 and 213. In the intermediate splicing part. the adhesives 202, 203, 212 and 213 includes a styrene-butadiene rubber or a mixture of styrene-butadiene rubber and styrene-isoprene rubber.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a connecting portion of a power cable, and more particularly to an intermediate connecting portion of a power cable that connects two power cables.

  Generally, an intermediate connection portion of a power cable that connects two power cables (for example, a CV cable) includes a cable conductor of one power cable (hereinafter referred to as “first power cable”) and the other power cable (hereinafter referred to as “second”). A power connection cable)) and a reinforcing insulation portion surrounding the outside of the conductor connection portion. Further, a protective tube is provided on the outer peripheral side of the reinforcing insulating portion, thereby preventing water from entering the intermediate connection portion of the power cable.

  Further, in order to prevent water from entering the conductor connection portion from the gap between the sheath (corrosion protection layer) of the power cable and the protective tube, an adhesive or the like is interposed between the sheath of the power cable and the protective tube. A waterproof tape is provided (see, for example, Patent Documents 1-4).

Japanese Patent Laid-Open No. 61-2781 Japanese Patent Laid-Open No. 7-3218 JP-A-9-247816 Japanese Patent Laying-Open No. 2015-142476

  By the way, conventionally, polyvinyl chloride (PVC) is used as the sheath of the power cable, and fiber reinforced plastics (FRP: Fiber Reinforced Plastics) is used as the protective tube for the intermediate connection, and the sheath is protected. An adhesive mainly composed of nitrile rubber or silicone rubber has been used as an adhesive provided between the pipes.

  However, high-density polyethylene (HDPE) is often used instead of PVC as the sheath of power cables for overseas markets. In addition, HDPE is friendly to the environment and the human body, and is advantageous in terms of cost, so it may be used as a material for the protective tube of the intermediate connection portion.

  In this way, when HDPE is used as the material for the sheath of the power cable and the protective tube of the intermediate connection part, the HDPE material is poor in adhesiveness. Therefore, an adhesive mainly composed of nitrile rubber or silicone rubber has sufficient adhesive strength. There is a problem that cannot be obtained. Although measures such as winding a self-adhesive synthetic rubber tape are taken against this problem, the gap between the interface between the cable sheath and the adhesive and the gap between the protective tube and the adhesive are completely removed. There was concern about the problem of water intrusion through the gap. This has been taken up as a major problem because it leads to water entering the inside of the protective tube through the gap between the waterproof tape wound by diameter matching and the protective tube.

  The present invention has been made in consideration of the above points, and provides a power cable connection portion having high waterproof performance even when polyethylene is used as a sheath for the power cable and a protective tube for the intermediate connection portion. To do.

One aspect of the connecting portion of the power cable of the present invention is:
A conductor connecting portion formed by connecting a cable conductor of the first power cable and a cable conductor of the second power cable, a reinforcing insulating portion surrounding the conductor connecting portion, and a protective tube surrounding the conductor connecting portion; A power cable connection comprising:
An adhesive applied to the surface of the protective tube at the end of the protective tube and the surface of the cable sheath of the power cable;
A self-bonding rubber provided to cover the adhesive;
Have
The protective tube and the cable sheath are made of polyethylene,
The adhesive includes styrene butadiene rubber or a mixture of styrene butadiene rubber and styrene isoprene rubber.

  According to the present invention, as the adhesive, a styrene butadiene rubber, or a mixture containing a mixture of styrene butadiene rubber and styrene isoprene rubber is used, so that the protective tube made of polyethylene and the interface between the cable sheath and the adhesive, and Adhesiveness can be enhanced at both the interface between the self-bonding rubber and the adhesive, and as a result, a power cable connecting portion having high waterproof performance can be realized.

Half sectional view of power cable connecting portion according to the present embodiment Cross section of the cable connection body

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Overall configuration>
FIG. 1 is a half sectional view of the intermediate connection portion 1 of the power cable according to the present embodiment. As shown in FIG. 1, the intermediate connection portion 1 of the power cable includes a cable connection portion main body 1A and a protective case 1B that surrounds the outside of the cable connection portion main body 1A. The protective case 1 </ b> B is a double-structured protective case having an inner protective tube 30 and an outer protective tube 40.

  A waterproof compound 50 (for example, a waterproof compound such as urethane) is filled between the cable connecting portion main body 1A and the protective case 1B and between the inner protective tube 30 and the outer protective tube 40. The protective case 1 </ b> B and the waterproof mixture 50 ensure water shielding of the intermediate connection portion 1 of the power cable. The internal protective tube 30 includes an insulating cylinder 33 and metal tubes 31 and 32.

  FIG. 2 is a cross-sectional view of the cable connecting portion main body 1A. As shown in FIG. 2, the cable connecting portion main body 1A includes a conductor connecting portion 10 in which a cable conductor 111 of the first power cable 11 and a cable conductor 121 of the second power cable 12 are connected, and a conductor connecting portion. 10 and a reinforcing insulating part 20 surrounding 10.

  Hereinafter, when the first power cable 11 and the second power cable 12 are not distinguished from each other, they are simply referred to as “power cables 11 and 12”.

  The power cables 11 and 12 are power cables (for example, CV cables) insulated with rubber or plastic. The power cables 11 and 12 are, in order from the inside, the cable conductors 111 and 121, the inner semiconductive layer (not shown), the cable insulators 112 and 122, the outer semiconductive layers 113 and 123, the cable shielding layers 114 and 124, respectively. Cable sheaths 115 and 125 are included.

  In the cable connection portion main body 1A, the layers of the power cables 11 and 12 are exposed by stepping off the terminal portions of the power cables 11 and 12 with a predetermined length. A conductive conductor connection tube 13 suitable for energization made of, for example, copper, aluminum, a copper alloy, or an aluminum alloy is compressed and connected to each of the cable conductors 111 and 121, whereby the conductor connection portion 10 is configured. . The cable conductors 111 and 121 are electrically connected via the conductor connection pipe 13.

  The reinforcing insulating portion 20 is a one-piece rubber block insulator in which an internal electrode 21, a rubber insulating portion 22, stress cone portions 23 and 24, and an external shielding layer 25 are integrally formed. The rubber insulating portion 22 has a cylindrical shape and is made of an elastic material such as silicone rubber.

  The internal electrode 21 is made of, for example, semiconductive silicone rubber, and is disposed on the inner peripheral surface of the central portion in the longitudinal direction of the rubber insulating portion 22. The internal electrode 21 and the conductor connection tube 13 are electrically connected. The internal electrode 21 and the conductor connection tube 13 may be electrically connected by winding a semiconductive tape around the outer periphery of the conductor connection tube 13 and bringing the semiconductive tape and the internal electrode 21 into contact with each other. And the conductor connection tube 13 may be electrically connected by being configured to be in direct contact with each other.

  The stress cone portions 23 and 24 are formed of a cylindrical body having a bell mouth shape, and are made of, for example, semiconductive silicone rubber. The stress cone portion 23 extends from the cable insulator 112 of the first power cable 11 to the external semiconductive layer 113, and the end portion is outside the one end portion 22a (the left end portion in FIG. 2) of the rubber insulating portion 22. It is formed to extend. The stress cone portion 24 extends from the cable insulator 122 of the second power cable 12 to the outer semiconductive layer 123, and the end portion is outside the other end portion 22 b (the right end portion in FIG. 2) of the rubber insulating portion 22. It is formed to extend.

  The outer shielding layer 25 has a cylindrical shape and is made of, for example, semiconductive silicone rubber. In FIG. 1, the illustration of the external shielding layer 25 is omitted for convenience of explanation. The outer shielding layer 25 is disposed on the outer peripheral surface of the rubber insulating portion 22, and at least the end portions 23a and 24a of the stress cone portions 23 and 24 on the center side of the connecting portion (the inner diameter of the stress cone portions 23 and 24 is increased). It is formed to be longer than the length between the end portions on the other side. This prevents the end of the external shielding layer 25 from becoming an electrical protrusion.

  Here, one end portion 25a (the left end portion in FIG. 2) of the external shielding layer 25 is slightly extended toward the cable sheath 115 side than the end portion 23a on the connection portion central portion side of the stress cone portion 23. On the other hand, the other end portion 25b (right end portion in FIG. 2) of the external shielding layer 25 is extended to the other end portion 22b (right end portion in FIG. 2) of the rubber insulating portion 22, and is stressed by a semiconductive tape (not shown). The cone portion 24 is electrically connected. That is, the external shielding layer 25 forms a one-edge cutting structure. The other end portion 25 b of the external shielding layer 25 may be extended to a position where it abuts on the stress cone portion 24 to form a one-edge cutting structure.

  The configuration of the external shielding layer 25 is not limited to this, and may be a double-sided edge-cutting structure, a single-sided edge-cutting structure, or a no-edge-cutting structure depending on the necessity of the edge-cutting structure of the reinforcing insulating portion 20. The external shielding layer 25 is not limited to semiconductive rubber, and may be formed of, for example, conductive paint.

  The inner peripheral surfaces of the internal electrode 21, the rubber insulating portion 22, and the stress cone portions 23 and 24 are formed flush with each other. The internal electrode 21, the stress cone portions 23 and 24, and the external shielding layer 25 (in the case of molding) are preferably formed of the same material (semiconductive silicone rubber) in terms of molding. The rubber insulating portion 22 is also preferably formed of an insulating material that does not have the same type of conductivity as these (for example, insulating silicone rubber).

  In the embodiment, the rubber block insulator forming the reinforcing insulating portion 20 has been described as being formed of silicone rubber, but may be formed of, for example, ethylene propylene rubber (EP rubber).

  The reinforcing insulating portion 20 is held in a state where the diameter is expanded by a diameter expanding member such as a spiral core in a factory, for example. Then, after the reinforcing insulating portion 20 is disposed so as to surround the conductor connecting portion 10 at the construction site, it is attached in close contact with the conductor connecting portion 10 by the self-shrinking force of rubber by pulling out the diameter expanding member. . Thereby, the insulation performance in the intermediate connection part 1 is ensured. In addition, the reinforcement insulation part 20 is not limited to what is called a factory diameter expansion type such as a spiral core, but may be a so-called field diameter expansion type that expands the diameter at a construction site using a diameter expansion jig or a diameter expansion device. An anticorrosion layer 36, 37 is formed between the insulating tube 33 and the cable sheaths 115, 125.

<Anti-corrosion structure>
Next, the anticorrosion structure according to the present embodiment will be described. Anticorrosion structures are provided on both end sides of the outer protective tube 40.

  This will be specifically described. Adhesives 202 and 212 are applied to the surface of the end portion of the outer protective tube 40. Adhesives 203 and 213 are also applied to the surfaces of the cable sheaths 115 and 125. The adhesives 203 and 213 extend at least from the end portion of the outer protective tube 40 so as to protrude to the side opposite to the conductor connection portion 10. Note that the adhesives 203 and 213 may extend from the outer protective tube 40 to a position where the adhesives 203 and 213 enter the conductor connecting portion 10.

  A self-fusing rubber 204 is provided on the adhesives 202 and 203, and a self-fusing rubber 214 is provided on the adhesives 212 and 213. The self-bonding rubbers 204 and 214 are provided so as to fill a gap between the outer peripheral surfaces of the cable sheaths 115 and 125 and the inner peripheral surface of the outer protective tube 40. In the present embodiment, the self-bonding rubbers 204 and 214 are made of butyl rubber. The self-bonding rubbers 204 and 214 are formed by winding a tape made of butyl rubber from above the adhesives 202, 203, 212, and 213.

  Further, glass tapes 205 and 215, epoxy adhesives 206 and 216, and waterproof tapes 207 and 217 are sequentially wound around the surface side of the self-bonding rubbers 204 and 214, whereby the power cable 11 , 12 and the outer protective tube 40 can be strengthened, and water from the end of the outer protective tube 40 to the conductor connecting portion 10 can be more reliably prevented.

  Here, in the case of the present embodiment, the adhesives 202, 203, 212, and 213 use styrene butadiene rubber as an adhesive component. Specifically, styrene butadiene rubber may be used alone as an adhesive component, or a mixture of styrene butadiene rubber and styrene isoprene rubber may be used.

  In practice, the adhesive component is melted in an organic solvent composed of cyclohexane, solvent naphtha, normal hexane or the like.

  Adhesives 202, 203, 212, and 213 of the present embodiment contain 30 to 50 parts by mass of an adhesive component made of styrene butadiene rubber alone or a mixture of styrene butadiene rubber and styrene isoprene rubber with respect to 100 parts by mass of organic solvent. doing.

  As a result, the adhesives 202, 203, 212, and 213 strongly adhere to the outer protective tube 40 made of HDPE and the cable sheaths 115 and 125 made of HDPE, and also strongly adhere to the self-bonding rubbers 204 and 214. become. As a result, the adhesive 202, 203, 212, 213 is submerged from the outer protective tube 40 or the cable sheath 115, 125 made of HDPE, and the adhesive 202, 203, 212, 213 is self-melted. It is possible to prevent any water from entering through the gaps caused by peeling off the adhesive rubbers 204 and 214.

  The table below shows the experimental results. In the experiment, a mixture of styrene butadiene rubber and styrene isoprene rubber or a styrene butadiene rubber alone was used as an adhesive component as in this embodiment (Examples 1 and 2), and a conventional adhesive component was used. Thus, it carried out in the case of using nitrile rubber, acrylic modified silicone resin, silylated urethane resin (Comparative Example 1, Comparative Example 2, Comparative Example 3).

The experiment was performed using HDPE as the adherend 1 and using a self-fusing tape made of butyl rubber as the adherend 2 and bonding the adherend 1 and the adherend 2 with an adhesive containing each adhesive component. . Specifically, after applying an adhesive to the adherend 1 and the adherend 2 at room temperature and bonding them together at room temperature, a load of 0.36 kgf / cm ² (about 1 kgf with respect to the bonding area) is applied. And allowed to stand for 24 hours. The thickness of the adhesive was 0.2 mm according to JIS K6850.

  As can be seen from the experimental results, as in Examples 1 and 2, a mixture of styrene butadiene rubber and styrene isoprene rubber or styrene butadiene rubber alone was used as an adhesive component of the adhesives 202, 203, 212, and 213. It was found that when 30 to 50 parts by mass of the adhesive component was contained with respect to 100 parts by mass of the organic solvent, water penetration did not occur and good water shielding was obtained. On the other hand, in Comparative Examples 1, 2, and 3, it was found that there was water intrusion and the water shielding was poor. Further, as in Reference Example 1 and Reference Example 2, even when a mixture of styrene butadiene rubber and styrene isoprene rubber or a styrene butadiene rubber is used alone as an adhesive component of the adhesives 202, 203, 212, and 213, organic When the adhesive component was contained in less than 30 parts by mass or more than 50 parts by mass with respect to 100 parts by mass of the solvent, there was no intrusion of water, but an adhesive breaking point was confirmed.

  Here, as in Example 1 and Example 2, when a mixture of styrene butadiene rubber and styrene isoprene rubber was used as the adhesive component of the adhesives 202, 203, 212, and 213, and styrene butadiene rubber was used alone. In any of the cases, there was no water intrusion, but the highest water barrier was obtained particularly when a mixture of styrene butadiene rubber and styrene isoprene rubber was used as the adhesive. This point will be described. Example 1 (a mixture of styrene butadiene rubber and styrene isoprene rubber) and Example 2 (styrene butadiene rubber alone) had no difference in adhesive strength with polyethylene. Examples 1 and 2 differed in that Example 1 (mixture) had a low reaction rate and Example 2 (alone) had a high reaction rate. At the manufacturing site, it is not always possible to wind the self-bonding rubber immediately after applying the adhesive during work, but in fact, the self-bonding rubber is wound after a few tens of minutes after application, resulting in a reaction. When Example 2 (single) having a high speed is used, there is a concern that the adhesive strength between the adhesive and the self-bonding rubber is lowered even if there is no difference in the adhesive strength with polyethylene. Therefore, it is most preferable to employ Example 1 (mixture) having a low reaction rate.

  As described above, according to the present embodiment, the adhesive 202 applied to the surface of the outer protective tube 40 and the surfaces of the HDPE cable sheaths 115 and 125 at the end of the HDPE outer protective tube 40, In the intermediate connection portion 1 having 203, 212, 213 and self-bonding rubbers 204, 214 provided so as to cover the adhesives 202, 203, 212, 213, the adhesives 202, 203, 212, 213 Of styrene butadiene rubber or a mixture of styrene butadiene rubber and styrene isoprene rubber, so that the outer protective tube 40 and the cable sheaths 115, 125 made of polyethylene and the adhesives 202, 203, 212, 213 Interface and self-bonding rubber 204, 214 and adhesive 202, 203, 212, 213 It is possible to improve the adhesiveness at both surfaces, as a result, can realize a connection of the power cable with high waterproof performance.

  In the above-described embodiment, the case where the anticorrosion structure according to the present invention is applied to the intermediate connection portion 1 of the RBJ (Rubber Block Joint) type power cable having the main insulating portion manufactured integrally has been described. The anticorrosion structure of the embodiment is not limited to this, and may be applied to an intermediate connection portion of another type of power cable.

  The above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. That is, the present invention can be implemented in various forms without departing from the gist or main features thereof.

  The present invention can be applied to an intermediate connection portion of a power cable having a cable sheath made of polyethylene.

DESCRIPTION OF SYMBOLS 1 Intermediate connection part 10 Conductor connection part 11, 12 Power cable 20 Reinforcement insulation part 22 Rubber insulation part 40 Outer protective tube 115, 125 Cable sheath 202, 203, 212, 213 Adhesive 204, 214 Self-fusing rubber 205, 215 Glass tape 206, 216 Epoxy adhesive 207, 217 Waterproof tape

Claims (4)

A conductor connecting portion formed by connecting a cable conductor of the first power cable and a cable conductor of the second power cable, a reinforcing insulating portion surrounding the conductor connecting portion, and a protective tube surrounding the conductor connecting portion; A power cable connection comprising:
An adhesive applied to the surface of the protective tube at the end of the protective tube and the surface of the cable sheath of the power cable;
A self-bonding rubber provided to cover the adhesive;
Have
The protective tube and the cable sheath are made of polyethylene,
The adhesive comprises styrene butadiene rubber or a mixture of styrene butadiene rubber and styrene isoprene rubber.
Power cable connection. The adhesive contains 30 to 50 parts by mass of an adhesive component composed of a mixture of styrene butadiene rubber and styrene isoprene rubber with respect to 100 parts by mass of the organic solvent.
The connection part of the electric power cable of Claim 1. The adhesive contains 30 to 50 parts by mass of an adhesive component made of styrene butadiene rubber with respect to 100 parts by mass of the organic solvent.
The connection part of the electric power cable of Claim 1. The self-bonding rubber is made of butyl rubber.
The connection part of the electric power cable as described in any one of Claims 1-3.

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