JP2015142477A - Outer protective tube and intermediate connection part of power cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an outer protective tube which is mild to the environment and a human body with excellent workability, and an intermediate connection part of a power cable.SOLUTION: An outer protective tube of a double structure protective case surrounding a cable connection part body comprises: a first protection cylinder made of synthetic resin which includes a flange part at an end; a second protection cylinder made of synthetic resin which is a symmetrical structure to the first protection cylinder with respect to the plane perpendicular to a longer direction, and which includes a flange part at an end, wherein the first protection cylinder and the second protection cylinder are connected in a water tight manner while facing respective flange parts to each other. The first protection cylinder or the second protection cylinder comprises: a ground wire lead-out part which leads out a ground wire grounding a cable shielding layer for a first power cable or a second power cable; and a waterproof mixture injection part through which waterproof mixture is injected into inside of the outer protective tube, wherein the ground wire lead-out part can be closed by screw fitting with a lid body.

Description

  The present invention relates to a protective case and a power cable connecting portion used for an intermediate connection portion of a power cable, and more particularly to an outer protective tube of a protective case having a double structure.

  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 cable connecting portion main body including a conductor connecting portion connected to a cable conductor of the power cable and a reinforcing insulating portion surrounding the outside of the conductor connecting portion. In particular, a rubber block joint (RBJ) using a one-piece rubber block insulator in which an internal electrode, a rubber insulating portion, a stress cone portion, and an external shielding layer are integrally formed is often used as a reinforcing insulating portion. Yes. Since the rubber block joint is excellent in workability, it is useful for shortening the construction period and consequently reducing the cost.

  Moreover, in order to prevent the inside of the intermediate connection part of a power cable from being flooded, a protective case is disposed on the outermost periphery of the intermediate connection part of the power cable (outside the cable connection part body) (for example, Patent Document 1). ~ 9). In Japan, the intermediate connection part of the power cable is often installed in the manhole, and the load on the intermediate connection part of the power cable is small. For this reason, the protective case is usually composed of a copper tube having a simple structure. On the other hand, in countries other than Japan, the intermediate connection portion of the power cable is often embedded in the cable pit, and the load applied to the intermediate connection portion of the power cable is larger than that in the case of installing in the manhole. Therefore, a protective case having a double structure of an inner protective tube and an outer protective tube is suitable.

  In the protective case having a double structure, a metal material that can be used as a current-carrying path when the cable shielding layer of the power cable is grounded is applied to the inner protective tube. In addition, fiber reinforced plastics (FRP: Fiber Reinforced Plastics) having relatively high mechanical strength, light weight and excellent handleability are applied to the outer protective tube.

Japanese Patent Laid-Open No. 9-224323 JP-A-9-275624 JP 7-193965 A Japanese Patent No. 4002248 Japanese Patent No. 5089328 JP 2003-87920 A Japanese Patent No. 3392296 JP 2011-83172 A Japanese Patent No. 4101203

As described in Patent Document 6, the outer protective tube is generally divided vertically by a plane along the longitudinal direction, and the divided surface is fastened with bolts or the like. However, in the case of the vertically divided structure, since the joining area is larger than that of the horizontally divided structure, the amount of bolts used is large and the workability is poor. In addition, the FRP outer protective tube is not suitable for ensuring high water tightness because it is difficult to finish the joint surface flat.
Furthermore, the FRP outer protective tube is environmentally problematic because FRP waste material that is disposed of by landfill is generated during manufacturing or dismantling. The outer protective tube made of FRP is not preferable for the human body because the glass fiber dust is scattered when it is cut or crushed.

  An object of the present invention is to provide an outer protective tube and a power cable connecting portion that are friendly to the environment and the human body and are excellent in workability.

An outer protective tube according to the present invention comprises: a conductor connecting portion formed by connecting a cable conductor of a first power cable and a cable conductor of a second power cable; and a reinforcing insulating portion surrounding the conductor connecting portion. An outer protective tube of a protective case of a double structure surrounding the cable connection body having
A synthetic resin first protective cylinder having a flange at the end, and a synthetic resin having a symmetrical structure with the first protective cylinder with respect to a plane perpendicular to the longitudinal direction, and having a flange at the end The second protective cylinder is connected in a watertight manner with the respective flange portions facing each other,
The first protective cylinder and the second protective cylinder each have a ground wire lead-out portion for drawing out a ground wire for grounding the cable shielding layer of the first power cable or the second power cable, respectively. A waterproof mixture injection portion for injecting the waterproof mixture into the outer protective tube,
The waterproof admixture injection part can be closed by screw fitting with a lid.

The intermediate connection portion of the power cable according to the present invention includes a conductor connection portion formed by connecting a cable conductor of the first power cable and a cable conductor of the second power cable, and a reinforcing insulating portion surrounding the conductor connection portion. And a cable connection body having:
A protective case having a double structure having an inner protective tube surrounding the cable connection body and the outer protective tube surrounding the inner protective tube;
A waterproof mixture is filled between the cable connection body and the protective case,
A lid is screwed into the waterproof admixture injection part.

  In the present invention, since the outer protective tube is made of synthetic resin and has a laterally divided structure, it is gentle to the environment and the human body and is excellent in workability.

It is a half sectional view of a power cable connection part concerning this embodiment. It is sectional drawing of a cable connection part main body. It is an external appearance perspective view of an inner side protection tube. It is sectional drawing of an inner side protection tube. It is an external appearance perspective view of an outer side protection tube. It is sectional drawing of an outer side protection tube.

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

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.

  FIG. 3 is an external perspective view of the inner protective tube 30. FIG. 4 is a cross-sectional view of the inner protective tube 30. As shown in FIGS. 3 and 4, the inner protective tube 30 includes an insulating cylinder 33, a first metal tube 31, and a second metal tube 32.

  The insulating cylinder 33 is made of a synthetic resin material (not including FRP). Synthetic resin materials have higher insulation than FRP, are environmentally friendly, and are extremely easy to mold into a desired shape. As the synthetic resin material, polyethylene or polyvinyl chloride, which has a density lower than that of the epoxy resin and can be easily reduced in weight, is preferable.

The insulating cylinder 33 has two through holes 331 and 331 on the peripheral surface. Here, the two through holes 331 and 331 are formed apart from each other in the longitudinal direction. The waterproof mixture 50 is injected through the through holes 331 and 331 and filled around the cable connection body 1A. In the present embodiment, the space between the inner protective tube 30 and the outer protective tube 40 is also filled with the waterproofing mixture 50, so that the water shielding treatment is not performed on the through holes 331 and 331.
Depending on the configuration of the outer protective tube 40, the through holes 331 and 331 of the inner protective tube 30 may need to be subjected to water shielding treatment. However, since the insulating cylinder 33 is made of synthetic resin, it can be easily closed by covering with an adhesive. can do. Compared to the case where a metal lid is soldered to the inlet provided in the copper tube as in the prior art, the workability is remarkably improved.

The exposed length of the insulating tube 33 (that is, the length in the longitudinal direction of the portion exposed on the outer periphery of the insulating tube 33) is the exposed length of the first metal tube 31 and the second metal tube 32 (that is, the first metal). The length in the longitudinal direction of the portion exposed in the outer periphery of the tube 31 and the length in the longitudinal direction of the portion exposed in the outer periphery of the second metal tube 32 are longer than the sum. In the intermediate connection portion 1, the exposed length of the insulating tube 33 of the inner protective tube 30 is longer than the length of the conductor connection portion 10. Thus, by forming the insulating cylinder 33 long, the two through holes 331 and 331 can be easily formed in the insulating cylinder 33. In addition, since the connection portion 34 between the first metal tube 31 and the insulating cylinder 33 is close to the cable sheath 115, and the connection portion 35 between the second metal tube 32 and the insulating tube 33 is close to the cable sheath 125, The anticorrosion treatment of the connecting portions 34 and 35 can be performed together with the end portions of the first metal tube 31 and the second metal tube 32.
When the metal tube is long as in the prior art, it is necessary to provide an anticorrosion layer in each of the connection portion between the metal tube and the insulating cylinder, and the connection portion between the metal tube and the cable sheath. Since the anticorrosion layers 36 and 37 can be formed together between the insulating tube 33 and the cable sheaths 115 and 125, workability is remarkably improved.

  The insulating cylinder 33 has at least one (for example, three) ring-shaped reinforcing ribs 332 on the outer peripheral surface. Thereby, since desired mechanical strength can be ensured without making the insulating cylinder 33 thicker than necessary, the weight of the inner protective tube 30 can be reduced.

  The first metal tube 31 is made of, for example, a copper tube that can be used as an energization path, and is connected to one end of the insulating tube 33. The first metal tube 31 is connected to the first inner cylindrical portion 311 and the first inner cylindrical portion 311 that are attached to the cable sheath 115 of the first power cable 11, and has a diameter that increases toward the center in the longitudinal direction. It has a cylindrical inner tapered portion 312 and a second inner cylindrical portion 313 connected to one end portion of the insulating tube 33 and connected to the inner tapered portion 312. Here, the first inner cylindrical portion 311 has a smaller diameter than the second inner cylindrical portion 313. For example, a part of the second inner cylindrical portion 313 is inserted into the insulating cylinder 33 and fixed by screwing.

  The second inner cylindrical portion 313 has a ground terminal seat 314 that protrudes outward in the radial direction (here, protrudes outward in the direction perpendicular to the longitudinal direction) in a portion exposed from the insulating cylinder 33. When the cable shielding layer 114 of the first power cable 11 is grounded, the cable shielding layer 114 is connected to the first metal pipe 31, and a grounding wire (not shown) connected to the grounding terminal seat 314 is a grounding wire to be described later. It is pulled out to the outside of the protective case 1B via the lead-out portion 416.

  The second metal tube 32 has a symmetric structure with the first metal tube 31 with respect to a plane perpendicular to the longitudinal direction. That is, the second metal tube 32 is made of, for example, a copper tube and is connected to the other end of the insulating tube 33. The second metal tube 32 is connected to the first inner cylindrical portion 321 and the first inner cylindrical portion 321 that are attached to the cable sheath 125 of the second power cable 12, and has a diameter that increases toward the center in the longitudinal direction. It has a cylindrical inner tapered portion 322 and a second inner cylindrical portion 323 connected to the other end portion of the insulating tube 33 and connected to the inner tapered portion 322. Here, the first inner cylindrical portion 321 has a smaller diameter than the second inner cylindrical portion 323. For example, a part of the second inner cylindrical portion 323 is inserted into the insulating cylinder 33 and fixed by screwing.

  The second inner cylindrical portion 323 has a ground terminal seat 324 that protrudes outward in the radial direction (here, protrudes outward in the direction perpendicular to the longitudinal direction) in a portion exposed from the insulating cylinder 33. When grounding the cable shielding layer 124 of the second power cable 12, the cable shielding layer 124 is connected to the second metal pipe 32, and a ground wire (not shown) connected to the ground terminal seat 324 is a ground wire described later. It is pulled out to the outside of the protective case 1B via the lead-out portion 426.

  As shown in FIGS. 3 and 4, it is preferable that the tip portions of the ground terminal seats 314 and 324 are bent in the longitudinal direction. Thereby, since the height of the ground terminal seats 314 and 324 is reduced and the space between the outer protective tube 40 can be reduced, the size of the protective case 1B can be reduced. 3 and 4, the tips of the ground terminal seats 314 and 324 are bent toward the insulating cylinder 33, but may be bent toward the opposite side.

  The inner protective tube 30 is inserted into the first power cable 11 or the second power cable 12 in advance, and is arranged so as to surround the cable connection body 1A after the cable connection body 1A is assembled. Then, the first inner cylindrical portion 311 is attached to the cable sheath 115 of the first power cable 11 by forming the anticorrosion layers 36 and 37 by tape winding, for example, and the second inner cylindrical portion 321 is the second power. It is attached to the cable sheath 125 of the cable 12. Further, the waterproof mixture 50 is injected through the through holes 331 and 331, and the waterproof mixture 50 is filled between the cable connecting portion main body 1 </ b> A and the inner protective tube 30.

  As described above, the inner protective tube 30 according to the present embodiment includes the insulating tube 33 made of synthetic resin, the first metal tube 31 connected to one end of the insulating tube 33, and the surface perpendicular to the longitudinal direction. And a second metal tube 32 having a symmetrical structure with the first metal tube 31 and connected to the other end of the insulating tube 33. The insulating cylinder 33 has a through-hole 331 for injecting the waterproofing mixture 50 into the space between the cable connecting portion main body 1 </ b> A and the inner protective tube 30, and the first metal tube 31 and the second metal tube 32. Respectively have grounding terminal seats 314 and 324 projecting outward in the radial direction. The exposed length of the insulating cylinder 33 is longer than the exposed length of the first metal tube 31 and the second metal tube 32.

  According to the protective case 1 </ b> B including the inner protective tube 30, the insulating cylinder 33 serves as an edge cut portion, and thus can correspond to an insulating joint. Moreover, since the assembly work is easy, it is excellent in workability.

  FIG. 5 is an external perspective view of the outer protective tube 40. FIG. 6 is a cross-sectional view of the outer protective tube 40. As shown in FIGS. 5 and 6, the outer protective tube 40 has a first protective cylinder 41 and a second protective cylinder 42.

The first protective cylinder 41 is connected to the first outer cylindrical portion 411 and the first outer cylindrical portion 411 that are attached to the cable sheath 115 of the first power cable 11, and has a diameter that increases toward the center in the longitudinal direction. A cylindrical outer tapered portion 412, a second outer cylindrical portion 413 provided continuously to the outer tapered portion 412, and a second outer cylindrical portion 413 formed along the longitudinal direction of the second outer cylindrical portion 413. A small-diameter cylindrical portion 415, a second outer cylindrical portion 413, and a cylindrical flange portion 414 that is formed at the end of the small-diameter cylindrical portion 415 and protrudes radially outward.
Here, the second outer cylindrical portion 413 has a larger diameter than the first outer cylindrical portion 411. The small diameter cylindrical portion 415 has a smaller diameter than the second outer cylindrical portion 413. That is, the shape of the cross section of the portion where the second outer cylindrical portion 413 and the small diameter cylindrical portion 415 of the first protective cylinder 41 are connected is a gourd type. Accordingly, in the present embodiment, the shape of the flange portion 414 is also a gourd shape.
A portion including the first outer cylindrical portion 411, the outer tapered portion 412, the second outer cylindrical portion 413, the small diameter cylindrical portion 415, and the flange portion 414 is a main body portion of the first protective cylinder 41.

  The first protective cylinder 41 has a ground wire lead portion 416 that pulls out a ground wire for grounding the cable shielding layer 114 of the first power cable 11. The ground wire lead portion 416 extends in the longitudinal direction of the small diameter cylindrical portion 415 so that the end portion protrudes from the main body portion (here, the position corresponding to the second outer cylindrical portion 413).

  The first protective cylinder 41 also has a waterproof mixture injection part 417 for injecting the waterproof mixture 50 into the space between the inner protective tube 30 and the outer protective tube 40. The waterproof admixture injecting portion 417 protrudes radially outward from the main body portion (here, the small diameter cylindrical portion 415) of the first protective cylinder 41 (here, protrudes outward in the direction perpendicular to the longitudinal direction). Formed.

The second protective cylinder 42 has a symmetrical structure with the first protective cylinder 41 with respect to a plane perpendicular to the longitudinal direction. That is, the second protective cylinder 42 is connected to the first outer cylindrical portion 421 and the first outer cylindrical portion 421 that are attached to the cable sheath 125 of the second power cable 12 and is directed toward the center in the longitudinal direction. A cylindrical outer tapered portion 422 that expands in diameter, a second outer cylindrical portion 423 provided continuously with the outer tapered portion 422, and a second outer cylindrical portion 423 formed along the longitudinal direction of the second outer cylindrical portion 423. A small-diameter cylindrical portion 425 that communicates with the second outer cylindrical portion 423 and a cylindrical flange portion 424 that is formed at the end of the small-diameter cylindrical portion 425 and protrudes radially outward.
Here, the second outer cylindrical portion 423 has a larger diameter than the first outer cylindrical portion 421. The small diameter cylindrical portion 425 has a smaller diameter than the second outer cylindrical portion 423. In other words, the shape of the cross section of the portion where the second outer cylindrical portion 423 and the small diameter cylindrical portion 425 of the second protective cylinder 42 are connected is a gourd type. Accordingly, in this embodiment, the shape of the flange portion 424 is also a gourd shape.
A portion including the first outer cylindrical portion 421, the outer tapered portion 422, the second outer cylindrical portion 423, the small diameter cylindrical portion 425, and the flange portion 424 serves as a main body portion of the second protective cylinder 42.

  The second protective cylinder 42 has a ground wire lead-out portion 426 that pulls out a ground wire for grounding the cable shielding layer 124 of the second power cable 12. The ground wire lead portion 426 extends in the longitudinal direction of the small diameter cylindrical portion 425 so that the end portion protrudes from the main body portion (here, the position corresponding to the second outer cylindrical portion 423).

  Further, the second protective cylinder 42 has a waterproof mixture injection part 427 for injecting the waterproof mixture 50 into the space between the inner protective tube 30 and the outer protective tube 40. The waterproof admixture injection portion 427 is formed so as to protrude radially outward from the main body portion (here, the small-diameter cylindrical portion 425) of the second protective cylinder 42.

  Male screws 416a, 426a, 417a, and 427a are formed at the ends of the ground wire lead portions 416 and 426 and the waterproof mixture injecting portions 417 and 427, respectively. The opening can be closed by fitting. When the ground wire is not pulled out, the water shielding treatment of the ground wire lead portions 416 and 426 and the water shielding treatment of the waterproof mixture injection portions 417 and 427 after filling with the waterproof mixture 50 are easy only by attaching the lid. And surely done. Therefore, the workability is remarkably improved as compared with the case where the anti-corrosion layer is formed by winding the tape to perform the water shielding treatment.

In addition, since the ground wire lead portions 416 and 426 and the waterproof mixture injection portions 417 and 427 are formed so as to protrude from the main body portion, the operation of attaching the lid body is extremely easy.
Further, when a ground wire is drawn out from the ground wire lead portion 416 (or 426), a corrosion prevention treatment (water shielding treatment) by tape winding is required between the ground wire and the ground wire lead portion 416 (or 426). However, since the ground wire lead portions 416 and 426 are formed so as to protrude from the main body portion, the workability of tape winding (anticorrosion treatment) is markedly greater than when the ground wire lead holes are simply open. improves.

The first protective cylinder 41 and the second protective cylinder 42 are connected in a watertight manner with the flange portions 414 and 424 facing each other. Specifically, a seal member 43 such as an O-ring or packing is interposed between the flange portions 414 and 424 and fastened with bolts. In the case of a laterally divided structure that divides by a plane perpendicular to the longitudinal direction, the bonding area is smaller than that of a longitudinally divided structure that divides by a plane along the longitudinal direction, which is effective in securing high water tightness, and Less bolts are needed.
In the present embodiment, the seal member 43 is a rubber packing. For example, when the seal member 43 is formed of an O-ring, grooves for accommodating the O-ring are provided on the end surfaces of the flange portions 414 and 424 so that the seal member 43 cannot be seen from the outside of the outer protective tube 40.

The first protective cylinder 41 and the second protective cylinder 42 are made of a synthetic resin material (not including FRP). The synthetic resin material has a higher water shielding property than FRP and can ensure a stable quality over a long period of time, so that the reliability is improved.
In addition, since the synthetic resin material is excellent in workability as compared with FRP, it can be easily adapted to the shape required for the intermediate connection portion 1 of the power cable, and can be reduced in size. When energizing a large current, it may be shaped to easily release heat generated by energization. By forming the first protective cylinder body 41 and the second protective cylinder body 42 from a synthetic resin material, the ground wire lead portions 416 and 426 and the waterproof mixture injection portions 417 and 427 have male screws 416a, 426a, 417a, and 427a. Can be easily formed, and the joint surfaces of the flange portions 414 and 424 can be finished flat. Therefore, high water tightness can be ensured. On the other hand, in the case of a conventional FRP protective tube (protective case), the sealing surface becomes a concavo-convex structure in forming the FRP, so that when the sealing surface is formed between the flange portions as in the present embodiment, it is waterproof. The performance is inferior.

Furthermore, since the synthetic resin material can be reused and waste materials to be disposed of at the time of manufacture or dismantling can be reduced, it is more environmentally friendly than FRP and has less influence on the human body.
As the synthetic resin material, polyethylene or polyvinyl chloride having a lower density and easier weight reduction than the epoxy resin is particularly suitable. In this case, since the material is the same as that of the cable sheaths 115 and 125, it is easy to cope with ant-proofing, anti-molding, and flame resistance by a multi-functional blend.

  The first protective cylinder 41 is inserted into the first power cable 11 in advance, and the second protective cylinder 42 is inserted into the second power cable 12 in advance. After the inner protective tube 30 is fixed at a predetermined position, the first protective cylinder 41 and the second protective cylinder 42 are fastened by bolts with the flange portions 414 and 424 facing each other. Then, for example, by forming the anticorrosion layers 44 and 45 by tape winding, the first outer cylindrical portion 421 is attached to the cable sheath 115 of the first power cable 11, and the second outer cylindrical portion 421 is the second outer cylindrical portion 421. Attached to the cable sheath 125 of the power cable 12.

  The waterproof mixture 50 is injected from the waterproof mixture injection portions 415 and 425, and the space between the inner protective tube 30 and the outer protective tube 40 is filled with the waterproof mixture 50. Thereafter, a lid is attached to the waterproof mixture injection portions 415 and 425 in a watertight manner by screw fitting.

  As described above, the outer protective tube 40 of the present embodiment includes the first protective cylinder 41 made of synthetic resin having the flange portion 414 at the end, and the first protective cylinder 41 with respect to the plane perpendicular to the longitudinal direction. The second protective cylinder 42 made of synthetic resin having a flange structure 424 at the end is connected in a watertight manner with the flange portions 414 and 424 facing each other. The first protective cylinder 41 and the second protective cylinder 42 are ground line leads for drawing out ground lines for grounding the cable shielding layers 114 and 124 of the first power cable 11 or the second power cable 12, respectively. Parts 416 and 426 and waterproof mixture injection parts 417 and 427 for injecting the waterproof mixture 50 into the outer protective tube 40. And at least one (both in the embodiment) of the ground wire lead portions 416 and 426 or the waterproof admixture injection portions 417 and 427 can be closed by screw fitting. The first protective cylinder 41 and the second protective cylinder 42 have the same structure as the embodiment (that is, a symmetrical structure as the outer protective tube 40), so that the cost is reduced in terms of productivity. Can be preferred.

  Since the outer protective tube 40 is made of synthetic resin and has a laterally divided structure, the protective case 1B including the outer protective tube 40 is gentle to the environment and the human body, and is excellent in workability.

As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the above embodiment, and can be changed without departing from the gist thereof.
For example, the inner protective tube 30 is not limited to the one described in the embodiment, and a known inner protective tube can be applied. For example, the inner protective tube may have a structure including a metal protective tube having a waterproof mixture inlet on both sides of an insulating tube made of epoxy resin or FRP.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 Intermediate connection 1 of power cable
DESCRIPTION OF SYMBOLS 1A Cable connection part main body 10 Conductor connection part 11, 12 Power cable 111, 121 Cable conductor 112, 122 Cable insulator 113, 123 External semiconductive layer 114, 124 Cable shielding layer 115, 125 Cable sheath 13 Conductor connection pipe 20 Reinforcement insulation Part 21 Internal electrode 22 Rubber insulating part 23, 24 Stress cone part 25 External shielding layer 1B Protective case 30 Inner protective tube 31 First metal tube 32 Second metal tube 33 Insulating tube 40 Outer protective tube 41 First protective tube Body 42 Second protective cylinder 43 Seal member 50 Waterproof admixture

Claims (7)

A cable connecting portion main body having a conductor connecting portion formed by connecting the cable conductor of the first power cable and the cable conductor of the second power cable and a reinforcing insulating portion surrounding the conductor connecting portion. An outer protective tube of a heavy-duty protective case,
A synthetic resin first protective cylinder having a flange at the end, and a synthetic resin having a symmetrical structure with the first protective cylinder with respect to a plane perpendicular to the longitudinal direction, and having a flange at the end The second protective cylinder is connected in a watertight manner with the respective flange portions facing each other,
The first protective cylinder and the second protective cylinder each have a ground wire lead-out portion for drawing out a ground wire for grounding the cable shielding layer of the first power cable or the second power cable, respectively. A waterproof mixture injection portion for injecting the waterproof mixture into the outer protective tube,
The outer protective tube, wherein the waterproof admixture injection part can be closed by screw fitting with a lid. The ground wire lead portion is formed to protrude in the longitudinal direction from the main body portion of the outer protective tube,
The outer protective tube according to claim 1, wherein the waterproof admixture injecting portion is formed to protrude in a radial direction from a main body portion of the outer protective tube.   The outer protective tube according to claim 1 or 2, wherein the ground wire lead-out portion can be closed by screw fitting with a lid.   4. The outer protective tube according to claim 1, wherein the first protective cylinder and the second protective cylinder are connected by a bolt via a seal member. 5.   The outer protective tube according to any one of claims 1 to 4, wherein the first protective cylinder and the second protective cylinder are made of polyethylene or polyvinyl chloride. A cable connecting portion main body having a conductor connecting portion formed by connecting a cable conductor of the first power cable and a cable conductor of the second power cable, and a reinforcing insulating portion surrounding the conductor connecting portion;
A double-structured protective case comprising: an inner protective tube surrounding the cable connecting portion main body; and an outer protective tube according to any one of claims 1 to 5 surrounding the inner protective tube. ,
A waterproof mixture is filled between the cable connection body and the protective case,
A power cable connecting portion, wherein a lid is screwed into the waterproof admixture injecting portion.   The power cable connecting portion according to claim 6, wherein the reinforcing insulating portion is a rubber block insulator.

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