JP2023163142A - Cable intermediate connection structure - Google Patents

Abstract

To provide a cable intermediate connection structure which is excellent in heat dissipation characteristics, and can be assembled by a simple method in a short time.SOLUTION: A cable intermediate connection structure includes: a conductor connection part which connects the end of a first power cable and the end of a second power cable, and connects the end of a first cable conductor of the first power cable and the end of a second cable conductor of the second power cable; a rubber unit covering the outer periphery of the conductor connection part; a shielding layer covering the outer periphery of the rubber unit; a protective layer covering the outer periphery of the shielding layer; a resin compound part which includes at least one of a plurality of compound blocks arranged so as to be divided in a circumferential direction of the protective layer, a compound sheet wound around the outer periphery of the protective layer, and a cylindrical compound block arranged so as to cover the outer periphery of the protective layer, and covers the outer periphery of the protective layer; and a metal pipe covering the outer periphery of the compound part.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a cable intermediate connection structure.

Conventionally, a cable intermediate connection structure in which the ends of power cables are connected to each other is known.

For example, Patent Document 1 describes a conductor connection section that connects the ends of cable conductors exposed at the ends of each power cable, a rubber unit that covers the outer periphery of the conductor connection section, and a rubber unit that covers the outer periphery of the rubber unit. , an intermediate connection structure for power cables is described, which includes a protective tube that covers a predetermined space, and a compound that fills the space. In the power cable intermediate connection structure of Patent Document 1, the protection tube is provided with an injection hole for injecting the compound into the space, and the inner diameter of the intermediate region of the protection tube that covers the outer periphery of the conductor connection portion is the same as that of the protection tube. It is smaller than the inner diameter of the outer region surrounding the outer periphery of each end of the rubber unit in the tube.

Further, Patent Document 2 discloses a conductor connection portion that connects cable conductors exposed at the ends of two power cables, a rubber unit that covers the outer periphery of the conductor connection portion, and a rubber unit that covers the outer periphery of the rubber unit. , an intermediate connection structure for a power cable is disclosed, which includes a protective tube that covers a predetermined space, and a compound that fills the space. In the power cable intermediate connection structure of Patent Document 2, a first boundary between one end of the rubber unit and one of the power cables, and a second boundary between the other end of the rubber unit and the other power cable. A shrinkable tube is provided in close contact with the outer circumferential surface of the rubber unit, and a first adhesive layer is provided on the outer circumferential surface of the shrinkable tube and brings the shrinkable tube and the compound into close contact.

As in Patent Document 1 and Patent Document 2, in assembling a conventional cable intermediate connection structure, first, before connecting the ends of the power cable, the diameter is expanded using a diameter expansion holding material such as an inner core or a diameter expansion pipe. Pass the rubber unit or protection tube through the power cable and make it standby at a part other than the end of the power cable. After the ends of the power cables are connected, the rubber unit that is waiting on the power cable in advance is moved to the connection part, the diameter expansion holding material is pulled out from the rubber unit, and the rubber unit is attached to the connection part. After that, move the protective tube that is already on standby to the power cable to the position of the rubber unit. Subsequently, a liquid compound is injected into the space between the rubber unit and the protection tube through an injection hole provided in the protection tube. After injecting the liquid compound, the injection hole of the protection tube is closed with a lid. In this way, the injection hole is waterproofed.

However, as mentioned above, conventional cable intermediate connection structures use liquid compounds. Therefore, when assembling the cable intermediate connection structure, it is necessary to mix and stir the liquid compound raw materials on site. Furthermore, the amount of time spent on compounding is long because the liquid compound is injected and cured. Further, the electrical resistance of the semiconductive members in the rubber unit and the power cable may decrease due to the liquid component contained in the injected liquid compound penetrating into the rubber unit and the power cable.

Further, since the protective tube is opaque and the injection hole is covered after the liquid compound is injected, it is impossible to know the filling state of the liquid compound injected into the space between the rubber unit and the protective tube. As a result, a large amount of air bubbles may be mixed inside the compound part that is the compound after curing, large gaps may be created between the compound part and the rubber unit or between the compound part and the protective tube, and the compound part may be filled unevenly. Due to such reasons, uniform heat dissipation of the cable intermediate connection structure is not achieved.

Further, the liquid compound may adhere to the periphery of the injection hole due to overflow of the liquid compound from the injection hole or a malfunction during injection of the liquid compound. Since the injection hole in such a state is covered on-site, the sealability of the injection hole is extremely unstable. If the sealing performance of the injection hole is poor, the insulation performance of the cable intermediate connection structure will be degraded.

JP 2019-41465 Publication JP2019-92322A

An object of the present disclosure is to provide a cable intermediate connection structure that has excellent heat dissipation characteristics and can be assembled in a simple manner and in a short time.

[1] A cable intermediate connection structure that connects an end of a first power cable and an end of a second power cable, wherein the end of the first cable conductor of the first power cable and the end of the second power cable are connected to each other. a conductor connection part that connects the ends of two cable conductors, a rubber unit that covers the outer periphery of the conductor connection part, a shielding layer that covers the outer periphery of the rubber unit, a protective layer that covers the outer periphery of the shielding layer, and the protection layer. At least one of a plurality of compound blocks divided and arranged in the circumferential direction of the layer, a compound sheet wound around the outer periphery of the protective layer, and a cylindrical compound block arranged over the outer periphery of the protective layer. A cable intermediate connection structure comprising: a resin compound part that covers the outer periphery of the protective layer; and a metal tube that covers the outer periphery of the compound part.
[2] The cable intermediate connection structure according to [1], wherein the cylindrical compound block includes one notch provided throughout the lengthwise direction, and the interval between the notches is expandable.
[3] When the finished outer diameter A of the compound part and the inner diameter B of the metal tube are the clearance c between the outer periphery of the compound part and the inner periphery of the metal tube, (B-A)/2. The cable intermediate connection structure according to [1] or [2] above, wherein the clearance c is 1.2% or more and 7.7% or less of the inner diameter B of the metal tube.
[4] The cable intermediate connection structure according to any one of [1] to [3] above, further comprising an adhesive layer provided between the protective layer and the compound portion.
[5] The cable intermediate connection structure according to any one of [1] to [4] above, wherein the compound portion has a Poisson's ratio of 0.48 or more and 0.50 or less.
[6] The method according to any one of [1] to [5] above, further comprising a low friction layer having a dynamic friction coefficient smaller than the dynamic friction coefficient of the compound part between the compound part and the metal tube. Cable intermediate connection structure.
[7] The cable intermediate connection structure according to [6] above, wherein the low-friction layer is composed of a low-friction tape.

According to the present disclosure, it is possible to provide a cable intermediate connection structure that has excellent heat dissipation characteristics and can be assembled in a short time using a simple method.

FIG. 1 is a longitudinal sectional view showing an example of a cable intermediate connection structure according to an embodiment. FIG. 2 is a perspective view showing an example of a compound part that constitutes the cable intermediate connection structure of the embodiment. FIG. 3 is a perspective view showing another example of the compound portion that constitutes the cable intermediate connection structure of the embodiment. FIG. 4 is a perspective view showing another example of the compound portion that constitutes the cable intermediate connection structure of the embodiment. FIG. 5 is a schematic diagram for explaining a method of attaching the compound portion shown in FIG. 4. FIG. 6 is a schematic diagram illustrating an example of a connection portion of metal tubes that constitute the cable intermediate connection structure of the embodiment. FIG. 7 is a schematic diagram illustrating another example of a metal tube connection part that constitutes the cable intermediate connection structure of the embodiment. FIG. 8 is a schematic diagram illustrating another example of a metal tube connection part that constitutes the cable intermediate connection structure of the embodiment.

Hereinafter, it will be explained in detail based on the embodiment.

As a result of extensive research, the present inventors focused on the structure of the compound part to improve heat dissipation characteristics, simplify assembly, and shorten assembly time.

The cable intermediate connection structure of the embodiment is a cable intermediate connection structure that connects an end of a first power cable and an end of a second power cable, wherein the end of a first cable conductor of the first power cable and the end of the first cable conductor of the first power cable are connected to each other. a conductor connection part that connects an end of a second cable conductor of a second power cable; a rubber unit that covers the outer periphery of the conductor connection part; a shielding layer that covers the outer periphery of the rubber unit; and a shielding layer that covers the outer periphery of the shielding layer. a protective layer, a plurality of compound blocks divided and arranged in a circumferential direction of the protective layer, a compound sheet wound around the outer periphery of the protective layer, and a cylinder placed over the outer periphery of the protective layer. A compound part made of resin includes at least one mold compound block and covers the outer periphery of the protective layer, and a metal tube covers the outer periphery of the compound part.

FIG. 1 is a longitudinal sectional view showing an example of a cable intermediate connection structure according to an embodiment. In addition, in FIG. 1, the first cable conductor 11a, the first cable insulator 12a, the first outer semiconducting layer 13a, the first semiconducting tape layer 14a, the first cable shielding layer 15a, and the first Cable sheath 16a, and second cable conductor 11b of second power cable 10b, second cable insulator 12b, second outer semiconducting layer 13b, second semiconducting tape layer 14b, second cable shielding layer 15b, second cable The sheath 16b is shown in a side view for convenience.

As shown in FIG. 1, a cable intermediate connection structure 1 of the embodiment is a power cable intermediate connection structure that connects an end of a first power cable 10a and an end of a second power cable 10b. The cable intermediate connection structure 1 includes a conductor connection part 2, a rubber unit 3, a shielding layer 4, a protective layer 5, a compound part 7, and a metal tube 9.

The first power cable 10a includes, from the center, a first cable conductor 11a, a first cable insulator 12a covering the outer periphery of the first cable conductor 11a, a first cable shielding layer 15a covering the outer periphery of the first cable insulator 12a, and a first cable shielding layer 15a covering the outer periphery of the first cable insulator 12a. 1 has a first cable sheath 16a that covers the outer periphery of the first cable shielding layer 15a. An internal semiconductive layer (not shown) is provided on the inner peripheral portion of the first cable insulator 12a. A first external semiconductive layer 13a and a first semiconductive tape layer 14a are provided on the outer peripheral portion of the first cable insulator 12a in this order from the inside. Due to the step stripping process of the first power cable 10a, the end portion of the first power cable 10a has a first cable conductor 11a, a first cable insulator 12a, a first outer semiconducting layer 13a, a first semiconducting tape layer 14a, A first cable shielding layer 15a is exposed from the first cable sheath 16a.

Similar to the first power cable 10a, the second power cable 10b also includes, from the center, a second cable conductor 11b, a second cable insulator 12b, a second cable shielding layer 15b, and a second cable sheath 16b. An internal semiconductive layer (not shown) is provided on the inner peripheral portion of the second cable insulator 12b. A second outer semiconductive layer 13b and a second semiconductive tape layer 14b are provided on the outer peripheral portion of the second cable insulator 12b in this order from the inside. Due to the step stripping process of the second power cable 10b, at the end of the second power cable 10b, the second cable conductor 11b, the second cable insulator 12b, the second outer semiconducting layer 13b, the second semiconducting tape layer 14b, A second cable shielding layer 15b is exposed from the second cable sheath 16b.

The first cable conductor 11a and the second cable conductor 11b are made of highly conductive metal such as copper, copper alloy, aluminum, and aluminum alloy. The first cable insulator 12a and the second cable insulator 12b are made of a highly electrically insulating resin such as crosslinked polyethylene. The inner semiconducting layer, the first outer semiconducting layer 13a, the second outer semiconducting layer 13b, the first semiconducting tape layer 14a, and the second semiconducting tape layer 14b are made of a semiconducting resin or the like. The first cable shielding layer 15a and the second cable shielding layer 15b are made of highly conductive metal such as copper, copper alloy, aluminum, and aluminum alloy. The first cable sheath 16a and the second cable sheath 16b are made of resin such as polyethylene or polyvinyl chloride.

The first power cable 10a and the second power cable 10b are, for example, CV cables (crosslinked polyethylene insulated vinyl sheath cables). The first power cable 10a and the second power cable 10b as described above are suitably used as high voltage cables or ultra-high voltage cables.

The cable intermediate connection structure 1 includes, from the center toward the outside, a conductor connection portion 2, a rubber unit 3, a shielding layer 4, a protective layer 5, a compound portion 7, and a metal tube 9. The conductor connection portion 2 constituting the cable intermediate connection structure 1 connects the end of the first cable conductor 11a of the first power cable 10a and the end of the second cable conductor 11b of the second power cable 10b. The cable intermediate connection structure 1 is, for example, generally symmetrical with respect to the central axis of the cable intermediate connection structure 1, and at the connection portion between the first cable conductor 11a and the second cable conductor 11b, the cable intermediate connection structure 1 is oriented in the axial direction of the cable intermediate connection structure 1. It is roughly symmetrical with respect to the direction perpendicular to .

The conductor connection portion 2 connects the ends of the first cable conductor 11a and the second cable conductor 11b that are exposed by step stripping of the ends of the first power cable 10a and the second power cable 10b. Connecting. For example, the conductor connection portion 2 has a cylindrical shape. The conductor connection part 2 is compressed with the first power cable 10a inserted from one end side of the conductor connection part 2 and the second power cable 10b inserted from the other end side of the conductor connection part 2. 2 electrically connects the first cable conductor 11a of the first power cable 10a and the second cable conductor 11b of the second power cable 10b.

From the viewpoint of high conductivity and compressibility, the conductor connection portion 2 is preferably made of copper, copper alloy, aluminum, or aluminum alloy. A semiconducting tape layer or the like may be provided on the outer circumferential surface of the conductor connection portion 2 and the exposed outer circumferential surfaces of the first cable conductor 11a and the second power cable 10b.

The rubber unit 3 configuring the cable intermediate connection structure 1 covers the outer periphery of the conductor connection portion 2 . The rubber unit 3 has a cylindrical shape and is the main insulating part of the cable intermediate connection structure 1. Here, the rubber unit 3 continuously covers the outer peripheral portion from the first outer semiconductive layer 13a of the first power cable 10a to the second outer semiconductive layer 13b of the second power cable 10b. The rubber unit 3 is installed so as to cover the outer periphery of the first power cable 10a and the second power cable 10b including the conductor connection portion 2 in an expanded state. Therefore, the inner peripheral surface of the rubber unit 3 is brought into close contact with the outer periphery including the conductor connection portion 2 due to the restoring force of the rubber unit 3.

The rubber unit 3 includes a main insulating part 31 , a cylindrical inner peripheral semi-conductive part 32 provided at the inner peripheral part of the central part of the main insulating part 31 in the axial direction of the cable intermediate connection structure 1 , and both ends of the main insulating part 31 . The main insulating part 31 has an end semi-conductive part 33 provided at the center thereof, and a cylindrical outer semi-conductive part 34 provided at the outer circumferential part of the central part of the main insulating part 31 in the axial direction.

The main insulating portion 31 of the rubber unit 3 covers the outer peripheral portion from the first cable insulator 12a of the first power cable 10a to the second cable insulator 12b of the second power cable 10b. The main insulating portion 31 is made of highly electrically insulating rubber, preferably insulating silicone rubber or insulating ethylene propylene rubber.

The inner semiconductive portion 32 covers the outer periphery of the conductor connection portion 2 . Each end semiconducting portion 33 is connected to the first outer semiconducting layer 13a and the second outer semiconducting layer 13b, respectively. A part of the main insulating section 31 is interposed between each end semiconductive section 33 and the outer peripheral semiconductive section 34 . The end semiconductive portion 33 and the outer peripheral semiconductive portion 34 are electrically insulated. The inner semiconductive portion 32, the end semiconductive portion 33, and the outer semiconductive portion 34 are made of semiconductive rubber, preferably semiconductive silicone rubber or semiconductive ethylene propylene rubber.

Furthermore, pedestal spacers 36 are provided at both ends of the rubber unit 3, respectively. The pedestal spacer 36 forms an inclined surface between the outer circumferential surface of the first outer semiconducting layer 13a or the second outer semiconducting layer 13b and the outer circumferential surface of the main insulating section 31. When the rubber unit 3 includes the pedestal spacer 36, the shielding layer 4, the protective layer 5, the compound portion 7, etc. can be easily attached. A semiconductive tape layer 35 is provided in the gap around the pedestal spacer 36.

A shielding layer 4 constituting the cable intermediate connection structure 1 covers the outer periphery of the rubber unit 3. The shielding layer 4 covering the rubber unit 3 connects the first cable shielding layer 15a of the first power cable 10a or the second cable shielding layer 15b of the second power cable 10b and the outer semiconductive part 34 of the rubber unit 3. . The shielding layer 4 is made of highly conductive metal such as copper, copper alloy, aluminum, and aluminum alloy.

A protective layer 5 constituting the cable intermediate connection structure 1 covers the outer periphery of the shielding layer 4 . A protective layer 5 covering the shielding layer 4 protects the shielding layer 4 . The protective layer 5 is made of highly electrically insulating rubber such as butyl rubber.

A resin compound portion 7 constituting the cable intermediate connection structure 1 covers the outer periphery of the protective layer 5 . The material constituting the compound portion 7 is, for example, the same as the material constituting a conventional liquid compound. The compound portion 7 is preferably made of a thermosetting resin with high heat dissipation properties and electrical insulation, and more preferably made of insulating silicone rubber, urethane resin, or insulating ethylene propylene rubber. The compound section 7 includes at least one of a plurality of compound blocks as shown in FIG. 2, a compound sheet as shown in FIG. 3, and a cylindrical compound block as shown in FIG. Note that in FIGS. 2 to 4, for convenience, components such as the protective layer 5 covered with the compound portion 7 are omitted, and the detailed tapered shape of the compound portion 7 is omitted.

As shown in FIG. 2, the compound section 7 is composed of a plurality of compound blocks 7a to 7d that are divided and arranged along the circumferential direction of the protective layer 5. The plurality of compound blocks 7a to 7d are attached to the outer periphery of the protective layer 5 in contact with each other along the circumferential direction of the protective layer 5. The compound section 7 composed of a plurality of compound blocks 7a to 7d has a cylindrical shape and covers the entire outer circumference of the protective layer 5. At the time of assembling the cable intermediate connection structure 1, the compound blocks 7a to 7d are not liquid compounds as in the prior art, but are solid, for example, molded resin bodies.

FIG. 2 shows an example in which the compound portion 7 is composed of four compound blocks 7a, 7b, 7c, and 7d having the same length and thickness in the circumferential direction, but if the compound portion 7 satisfies the above configuration, , the compound section 7 does not have to be composed of a plurality of compound blocks having the same shape. For example, the number of compound blocks may be two or three, or five or more. Moreover, the circumferential length and thickness of the compound blocks may be different. When the compound blocks have the same thickness, the metal tube 9 can be easily attached to the compound portion 7, and the cable intermediate connection structure 1 has good heat dissipation characteristics.

Further, as shown in FIG. 3, the compound section 7 is composed of a compound sheet 7e wound around the outer periphery of the protective layer 5. The compound sheet 7e is wound around the outer circumference of the protective layer 5 at least once. The compound portion 7 made of the compound sheet 7e has a cylindrical shape and covers the entire outer circumference of the protective layer 5. At the time of assembling the cable intermediate connection structure 1, the compound sheet 7e is not a conventional liquid compound but a solid, for example, a resin sheet.

Although FIG. 3 shows an example in which the compound section 7 is composed of one compound sheet 7e, as long as the compound section 7 satisfies the above configuration, the compound section 7 does not need to be composed of one compound sheet 7e. . For example, the compound section 7 may be composed of two or more compound sheets 7e. In this case, a plurality of compound sheets 7e having a length shorter than the outer circumference of the protective layer 5 may be placed over the outer circumference of the protective layer 5.

Further, as shown in FIG. 4, the compound section 7 is composed of a cylindrical compound block 7f placed over the outer periphery of the protective layer 5. The cylindrical compound block 7f includes one notch 71 provided over the entire longitudinal direction of the cylindrical compound block 7f, and the interval between the notches 71 can be expanded. The cut portion 71 is provided from one end to the other end of the cylindrical compound block 7f. For example, the shape of the notch 71 is linear as shown in FIG. Further, the cylindrical compound block 7f is an elastic body in which the interval between the notches 71 can be expanded. The cylindrical compound block 7f is cylindrical and covers the entire outer circumference of the protective layer 5. At the time of assembling the cable intermediate connection structure 1, the cylindrical compound block 7f is not a conventional liquid compound but a solid, for example, a resin molded body.

FIG. 5 is a schematic diagram for explaining a method of mounting the compound section 7 made up of the cylindrical compound block 7f shown in FIG. 4. The interval between the notches 71 of the cylindrical compound block 7f can be expanded by an external force. Specifically, when an external force is applied to the cylindrical compound block 7f so that the first dividing surface 72a and the second dividing surface 72b formed by the notch 71 separate from each other, the notch 71 expands as shown in FIG. However, when the external force applied to the cylindrical compound block 7f is released, the expanded notch 71 contracts, and the first dividing surface 72a and the second dividing surface 72b come into contact as shown in FIG. In this way, the cylindrical compound block 7f is arranged to cover the outer periphery of the protective layer 5.

FIG. 4 shows an example in which the compound section 7 is composed of one cylindrical compound block 7f, but if the compound section 7 satisfies the above configuration, the compound section 7 is composed of one cylindrical compound block 7f. You don't have to. For example, the compound section 7 may be composed of two or more cylindrical compound blocks 7f.

In this way, when assembling the cable intermediate connection structure 1, the compound portion 7 constituting the cable intermediate connection structure 1 is not a liquid compound as in the conventional case but is a solid compound. The compound portion 7 can be attached to the outer periphery of the protective layer 5 by installing a plurality of compound blocks 7a to 7d or a cylindrical compound block 7f or by winding the compound sheet 7e. This eliminates the need for conventional work such as mixing, stirring, and pouring liquid compounds at the assembly site, and also eliminates the need to wait for liquid compounds to harden. Therefore, the compound section 7 can be installed in a simple manner, and the working time spent on the compound section 7 can be significantly shortened. Note that an adhesive (not shown) may be provided on the side surfaces of the plurality of compound blocks 7a to 7d for temporarily fixing the compound blocks 7a to 7d to each other during assembly. Furthermore, for the same purpose, an adhesive (not shown) may be provided on the surface of the compound sheet 7e and on the first dividing surface 72a and the second dividing surface 72b of the cylindrical compound block 7f.

Further, the compound portion 7 attached to the outer periphery of the protective layer 5 is solid. The liquid component contained in the liquid compound does not enter the rubber unit 3, the first power cable 10a, the second power cable 10b, etc. Therefore, it is possible to avoid deterioration of the electrical insulation and semiconductive conductivity of the cable intermediate connection structure 1 due to the liquid components contained in the liquid compound.

The compound section 7 may be composed only of the plurality of compound blocks 7a to 7d, may be composed only of the compound sheet 7e, or may be composed of the cylindrical compound block 7f. Furthermore, the compound section 7 may be composed of the above-mentioned compound block and compound sheet 7e.

Further, the Poisson's ratio of the compound portion 7 is preferably 0.48 or more and 0.50 or less. If the Poisson's ratio of the compound part 7 is within the above range, even if a local force is applied to the outer periphery of the compound part 7 when the metal tube 9 is attached to the outer periphery of the compound part 7, the restoring force of the compound part 7 will be reduced. Accordingly, the filling rate of the compound portion 7 between the protective layer 5 and the metal tube 9 can always be maintained at a predetermined level or higher.

A metal tube 9 is attached to the outer periphery of the compound portion 7 provided on the outer periphery of the protective layer 5 . The metal tube 9 has a cylindrical shape and covers the outer periphery of the compound portion 7 . Here, the metal tube 9 continuously covers the outer peripheral portion from the first cable shielding layer 15a of the first power cable 10a to the second cable shielding layer 15b of the second power cable 10b.

In the cable intermediate connection structure 1 of the embodiment, the metal tube 9 is attached to the compound portion 7 that has already been attached. The metal tube 9 does not have an injection hole for injecting a liquid compound like the conventional one. The shape of the inner periphery of the metal tube 9 is appropriately set according to the shape of the outer periphery of the compound portion 7. Here, on each end side of the metal tube 9, the inner surface of the end portion is electrically connected to the first cable shielding layer 15a and the second cable shielding layer 15b, and the end portion is waterproofed by the waterproof section 100. The metal tube 9 is made of metal, preferably copper, copper alloy, aluminum, or aluminum alloy.

Further, the metal tube 9 is composed of a plurality of metal members. For example, the metal tube 9 is formed by connecting a plurality of metal members in the axial direction of the cable intermediate connection structure 1 or by connecting a plurality of metal members in the circumferential direction of the cable intermediate connection structure 1. , assembled.

When assembling the metal tube 9 by connecting a plurality of metal members in the axial direction of the cable intermediate connection structure 1, the metal tube 9 has two metal members, ie, a first metal member, as shown in FIGS. 6 to 8, for example. It is composed of a member 9a and a second metal member 9b. The first metal member 9a covers the outer periphery of the compound portion 7 on the first power cable 10a side in the axial direction of the cable intermediate connection structure 1, and the second metal member 9b covers the outer periphery of the compound portion 7 on the second power cable 10b side. Cover the outer periphery of the

As an example, as shown in FIG. 6, at the connection portion between the first metal member 9a and the second metal member 9b, an O A sealing member 92 such as a ring is attached. Further, as shown in FIG. 7, a sealing member 92 such as an O-ring is installed in the recess 91 provided at each end of the first metal member 9a and the second metal member 9b, and a bolt 94 is inserted into the hole 93. By tightening the first metal member 9a and the second metal member 9b, the first metal member 9a and the second metal member 9b are connected. Further, as shown in FIG. 8, a seal member 92 such as an O-ring is attached to a recess 91 provided in a flange portion 95 formed at each end of the first metal member 9a and the second metal member 9b, By inserting the bolt 97 into the through hole 96 and tightening it, the first metal member 9a and the second metal member 9b are connected.

As described above, the compound portion 7 is not a liquid compound injected and hardened at the assembly site of the cable intermediate connection structure. Furthermore, the metal tube 9 is attached to the compound section 7 that has already been installed. Therefore, it is not necessary to install the metal tube 9 with a predetermined space between the protective layer and the protective layer on which the compound portion is not installed, as in the conventional case. Furthermore, there is no need to design the internal shape of the metal tube 9 in order to improve the filling rate of the liquid compound. The degree of freedom in designing the metal tube 9 is higher than in the past.

The cable intermediate connection structure 1 of the embodiment eliminates filling problems caused by conventional injected and hardened compound parts, such as large gaps occurring between the compound part and the protective layer and between the compound part and the metal pipe. This can be avoided, and a compound portion of a predetermined ratio can be uniformly and reliably provided between the protective layer 5 and the metal tube 9. That is, since the cable intermediate connection structure 1 has a structure in which the compound portion 7 is attached, the filling rate of the compound portion 7 between the protective layer 5 and the metal tube 9 is very stable and always equal to or higher than a predetermined value. The cable intermediate connection structure 1 can exhibit stable heat dissipation characteristics.

In addition, in the cable intermediate connection structure 1, the outer circumference of the compound portion 7 and the metal tube 9 are defined as the finished outer diameter A of the compound portion 7 composed of a compound block, a compound sheet, and a cylindrical compound block, and the inner diameter B of the metal tube 9. When the clearance c between the metal tube 9 and the inner circumference is (B-A)/2, the clearance c is preferably 1.2% or more and 7.7% or less of the inner diameter B of the metal tube 9. The finished outer diameter A of the compound portion 7 is the outer diameter of the compound portion 7 after being attached to the outer periphery of the protective layer 5, in other words, the outer diameter of the compound portion 7 disposed on the outer periphery of the protective layer 5. Hereinafter, for example, when the clearance c is 1.2% of the inner diameter B of the metal tube 9, it may be simply referred to as a clearance of 1.2%.

When the clearance c is 0 mm, the heat dissipation of the cable intermediate connection structure 1 is the best, but when the clearance c is 1.2% or more of the inner diameter B of the metal tube 9, the ease of attaching the metal tube 9 is improved.

In addition, when the cable conductor far from the conductor connection part 2 (distance at which the temperature set as a reference does not fluctuate according to temperature analysis; 4 m or more) is set to the maximum temperature (hereinafter referred to as the maximum cable conductor temperature), the clearance c is If it is 7.7% or less of the inner diameter B of the metal tube 9, the maximum cable conductor temperature and the maximum temperature of the cable conductor in the cable intermediate connection structure (hereinafter referred to as the maximum temperature of the cable conductor in the cable intermediate connection structure) The ratio of the difference (|cable conductor maximum temperature - conductor maximum temperature in the cable intermediate connection structure | x 100/cable conductor maximum temperature) can be less than 11%. If this ratio, that is, the rate of temperature increase, is less than 11%, the cable intermediate connection structure will not become a thermal weakness even if the cable conductor is used as a temperature control point. More preferably, the clearance c is 6.0% or less of the inner diameter B of the metal tube 9.

The inner diameter B of the metal tube 9 was fixed at 130 mm (inner radius 65 mm) or 148 mm (inner radius 74 mm), the finished outer diameter A was changed and the clearance C was changed, and the thermal conductivity of the compound part was 3.7 × 10 ^-4. W/(mmK), calculation results are shown assuming that the cable conductor temperature at a distance (4 m or more) from the conductor connection portion is approximately 90°C.

1) When B = 130 mm, the maximum temperature of the cable conductor is 90.1°C, and the maximum temperature of the conductor in the cable intermediate connection structure is 95.0°C (temperature increase rate 5.4%) with 0% clearance.
With a clearance of 1.2% (=0.8mm), the maximum temperature of the cable conductor is 90.1°C, and the maximum temperature of the conductor in the cable intermediate connection structure is 96.0°C (temperature increase rate 6.6%).
With a clearance of 6.0% (=3.9mm), the maximum temperature of the cable conductor is 90.1°C, and the maximum temperature of the conductor in the cable intermediate connection structure is 98.0°C (temperature increase rate of 8.8%).
With a clearance of 7.7% (=5.0mm), the maximum temperature of the cable conductor is 90.1°C, and the maximum temperature of the conductor in the cable intermediate connection structure is 99.1°C (temperature increase rate 10.0%).
Without a compound part, the maximum temperature of the cable conductor is 90.1°C, and the maximum temperature of the conductor in the cable intermediate connection structure is 106.2°C (temperature increase rate 17.9%).

2) When B = 148 mm, the maximum temperature of the cable conductor is 90.1°C, and the maximum temperature of the conductor in the cable intermediate connection structure is 95.6°C (temperature increase rate 6.1%) with 0% clearance.
With a clearance of 1.2% (=0.9mm), the maximum temperature of the cable conductor is 90.1°C, and the maximum temperature of the conductor in the cable intermediate connection structure is 96.3°C (temperature increase rate of 6.9%).
With a clearance of 6.0% (=4.4mm), the maximum temperature of the cable conductor is 90.1°C, and the maximum temperature of the conductor in the cable intermediate connection structure is 98.5°C (temperature increase rate of 9.3%).
With a clearance of 7.7% (=5.7mm), the maximum temperature of the cable conductor is 90.1°C, and the maximum temperature of the conductor in the cable intermediate connection structure is 99.3°C (temperature increase rate 10.2%).
Without a compound part, the maximum temperature of the cable conductor is 90.1°C, and the maximum temperature of the conductor in the cable intermediate connection structure is 110.7°C (temperature increase rate 22.9%).

In the cable intermediate connection structure of the embodiment, the temperature increase rate within the cable intermediate connection structure can be suppressed to less than 11% with respect to the maximum temperature of the cable conductor.
In addition, if there is no compound part, the maximum temperature of the conductor in the cable intermediate connection structure exceeds 100 degrees Celsius, and the temperature of the cable conductor connection becomes a bottleneck, making it impossible to conduct sufficient current to the power cable, resulting in power transmission. We have no choice but to reduce capacity.

Further, in the cable intermediate connection structure 1, since there is no need to inject liquid compound, the metal tube 9 does not need an injection hole for injecting liquid compound. The unstable sealing of the injection hole caused by liquid compound adhering to the periphery of the injection hole, as in the prior art, is eliminated. The airtightness and watertightness of the metal tube 9 can always be maintained at a stable high level by using a sealing member such as an O-ring as shown in FIGS. 6 to 8, for example. Therefore, deterioration of the insulation performance of the cable intermediate connection structure 1 can be suppressed.

Further, the cable intermediate connection structure 1 may further include an adhesive layer 6 provided between the protective layer 5 and the compound portion 7, as shown in FIG. A protective layer 5 covering the outer periphery of the shielding layer 4 protects the shielding layer 4 . The protective layer 5 is made of highly electrically insulating rubber such as butyl rubber. An adhesive layer 6 provided between the outer periphery of the protective layer 5 and the inner periphery of the compound portion 7 bonds the protective layer 5 and the compound portion 7 together. When the adhesive layer 6 is provided, the compound portion 7 can be easily attached when the cable intermediate connection structure 1 is assembled. When assembling the cable intermediate connection structure 1, the adhesive layer 6 may be provided only on the outer periphery of the protective layer 5, the adhesive layer 6 may be provided only on the inner periphery of the compound portion 7, or the adhesive layer 6 may be provided only on the inner periphery of the compound portion 7. It may be provided on the outer periphery of the protective layer 5 and the inner periphery of the compound portion 7. For example, the adhesive layer 6 is made of a thermoplastic resin such as a polyolefin resin, a polyester resin, or a polyamide resin.

Further, as shown in FIG. 1, the cable intermediate connection structure 1 may further include a low friction layer 8 having a dynamic friction coefficient smaller than that of the compound part 7 between the compound part 7 and the metal tube 9. preferable. When the low friction layer 8 is provided between the outer periphery of the compound section 7 and the inner periphery of the metal tube 9, it becomes easy to attach the metal tube 9 to the outer periphery of the compound section 7 when assembling the cable intermediate connection structure 1. .

Among these, it is preferable that the low friction layer 8 is composed of a low friction tape. The low-friction tape is preferably Nitoflon tape, VALFLON tape, Teflon tape, or the like.

For example, when assembling the cable intermediate connection structure 1, the low friction layer 8 is provided only on the outer periphery of the compound portion 7.

Next, a method of assembling the cable intermediate connection structure of the embodiment will be described.

The method for assembling the cable intermediate connection structure 1 described above mainly includes a process of connecting cable conductors (process 1), a process of installing a rubber unit (process 2), and a process of installing a shielding layer (process 3). , a step of installing a protective layer (step 4), a step of installing a compound part (step 5), and a step of installing a metal tube (step 6).

In step 1, the first cable conductor 11a exposed from the end of the first power cable 10a and the second cable conductor 11b exposed from the end of the second power cable 10b were inserted into the conductor connection part 2. In this state, the first power cable 10a and the second power cable 10b are connected by compressing the conductor connection portion 2.

At the end of the first power cable 10a, the first cable conductor 11a, the first cable insulator 12a, the first outer semiconducting layer 13a, the first semiconducting tape layer 14a, and the first cable shielding layer 15a are subjected to a step stripping process. is exposed from the first cable sheath 16a. Similarly, at the end of the second power cable 10b, the second cable conductor 11b, the second cable insulator 12b, the second outer semiconducting layer 13b, the second semiconducting tape layer 14b, the second cable A shielding layer 15b is exposed from the second cable sheath 16b.

Before connecting the first power cable 10a and the second power cable 10b, the rubber unit 3 is passed through the first power cable 10a and the second power cable 10b in a state in which the diameter has been expanded by the diameter expansion holding material, Make it standby at a part other than the end of the cable. Further, the first metal member 9a is passed through the first power cable 10a and is placed on standby at a portion other than the end of the first power cable 10a, and the second metal member 9b is passed through the second power cable 10b and the second power cable It may be made to wait at a portion other than the end portion of 10b.

In step 2 carried out after step 1, a rubber unit 3 is installed around the outer periphery of the conductor connecting portion 2, and the outer periphery of the conductor connecting portion 2 is covered with the rubber unit 3. After connecting the first power cable 10a and the second power cable 10b at the conductor connection part 2, move the rubber unit 3 in the expanded diameter state to the outer periphery of the conductor connection part 2, and remove the diameter expansion holding material from the rubber unit 3. remove Due to the restoring force of the rubber unit 3, the rubber unit 3 is brought into close contact with the outer periphery of the conductor connection portion 2.

In step 3 performed after step 2, a shielding layer 4 is installed around the outer periphery of the rubber unit 3, and the outer periphery of the rubber unit 3 is covered with the shielding layer 4. For example, in the above step 1, the rubber unit 3 with the shielding layer 4 on the outer periphery is made to stand by at a part other than the end of the power cable, and in the above step 2, the rubber unit 3 with the shielding layer 4 on the outer periphery is placed on standby. It may also be attached to the conductor connection part 2. Further, the rubber unit 3 attached in step 2 may be coated with the shielding layer 4.

In step 4, which is carried out after step 3, a protective layer 5 is provided around the outer periphery of the shielding layer 4, and the outer periphery of the shielding layer 4 is covered with the protective layer 5. For example, in the above step 1, the rubber unit 3 on which the protective layer 5 and the shielding layer 4 are attached in advance on the outer periphery is made to stand by at a part other than the end of the power cable, and in the above step 2, the protective layer 5 and the shielding layer 4 A rubber unit 3 having a rubber unit 3 on the outer periphery may be attached to the conductor connecting portion 2. Further, the shielding layer 4 attached in step 3 may be coated with the protective layer 5.

In Step 5, which is carried out after Step 4, a compound portion 7 is installed on the outer periphery of the protective layer 5, and the outer periphery of the protective layer 5 is covered with the compound portion 7. When the compound section 7 is composed of a plurality of compound blocks 7a to 7d, the plurality of compound blocks 7a to 7d are placed around the outer periphery of the protective layer 5. Further, when the compound portion 7 is composed of a compound sheet 7e, the compound sheet 7e is wound around the outer periphery of the protective layer 5. Further, when the compound portion 7 is composed of a cylindrical compound block 7f, the cylindrical compound block 7f is installed on the outer periphery of the protective layer 5.

Step 5 eliminates the need for mixing, stirring, and pouring of a liquid compound as in the past, and also eliminates the need to wait for the liquid compound to harden. Therefore, the compound section 7 can be installed in a short time using a simple method.

When the cable intermediate connection structure 1 includes an adhesive layer 6, the adhesive layer 6 is provided on the outer periphery of the protective layer 5 and the inner periphery of the compound 7 before step 5. For example, in the above step 1, the rubber unit 3 on which the adhesive layer 6, the protective layer 5, and the shielding layer 4 are attached in advance on the outer periphery is made to stand by at a portion other than the end of the power cable, and in the above step 2, the adhesive layer 6 , a rubber unit 3 having a protective layer 5 and a shielding layer 4 on its outer periphery may be attached to the conductor connection portion 2. Further, an adhesive layer 6 may be provided on the protective layer 5 attached in step 4. Further, in step 5, a compound portion 7 having an adhesive layer 6 on the inner surface may be attached to the protective layer 5. That is, before attaching the compound part 7 to the protective layer 5, the adhesive layer 6 may be provided only on the outer periphery of the protective layer 5, or the adhesive layer 6 may be provided only on the inner periphery of the compound part 7, The adhesive layer 6 may be provided on the outer periphery of the protective layer 5 and the inner periphery of the compound portion 7.

In Step 6 carried out after Step 5, a metal tube 9 is installed around the outer periphery of the compound section 7, and the outer periphery of the compound section 7 is covered with the metal tube 9. The first metal member 9a and the second metal member 9b, which have been placed on standby in advance at a portion other than the end of the power cable, are moved to the outer periphery of the compound portion 7 and connected to each other. In this way, the metal tube 9 is assembled. As another method for assembling the metal tube 9, in step 4, a plurality of metal members constituting the metal tube 9 are assembled into the compound section 7 without making the first metal member 9a and the second metal member 9b stand by with a power cable in advance. be installed and connected over the outer periphery of the

When the cable intermediate connection structure 1 includes the low friction layer 8, the low friction layer 8 is provided on the outer periphery of the compound portion 7 before step 6. In this way, the cable intermediate connection structure 1 is assembled.

As described above, according to the cable intermediate connection structure 1 of the embodiment, attention is paid to the structure of the compound portion 7, and the compound portion 7 is made of a compound block, a compound sheet, a cylindrical compound block, rather than a conventional liquid compound. This structure has excellent heat dissipation properties and can be assembled in a simple manner and in a short time.

Although the embodiments have been described above, the present invention is not limited to the above embodiments, but includes all aspects included in the concept of the present disclosure and the scope of the claims, and may be variously modified within the scope of the present disclosure. be able to.

Next, Examples and Comparative Examples will be described, but the present invention is not limited to these Examples.

(Example 1 and Comparative Examples 1-2)
As Example 1, a cable intermediate connection structure was assembled from FIG. 1 except that the adhesive layer 6 and the low-friction layer 8 were removed. Further, as Comparative Example 1, a cable intermediate connection structure was assembled from FIG. 1 except that the adhesive layer 6, compound portion 7, and low friction layer 8 were removed. That is, the cable intermediate connection structure of Comparative Example 1 did not include the compound portion 7. Moreover, as Comparative Example 2, a liquid compound raw material was used.

Specifically, in Example 1, a 2 mm thick urethane resin sheet was used as the compound sheet. The compound sheet was wound around the outer periphery of the protective layer 5 (outer diameter 108 mm) to form a compound portion 7 with a thickness of 18 mm (finished outer diameter 144 mm). Thereafter, a metal tube 9 (inner diameter 148 mm) was installed around the outer periphery of the compound section 7. The clearance c was 2 mm, which was 1.4% of the inner diameter of the metal tube. In this way, the cable intermediate connection structure was assembled.

In Comparative Example 1, the metal tube was installed with respect to the protective layer so that a space was provided between the outer periphery of the protective layer and the inner periphery of the metal tube.

In Comparative Example 2, liquid polyisocyanate and liquid polyol, which are raw materials for urethane resin, were stirred and injected into the space of Comparative Example 1 through the injection hole of the metal tube. Thereafter, the above space was filled after waiting until the polyol reaction was completed. In this way, the cable intermediate connection structure was assembled.

(Example 2)
Regarding Example 1, a cable intermediate connection structure was assembled in the same manner as in Example 1, except that the configuration of the compound portion was changed from a compound sheet to a plurality of compound blocks. Specifically, four compound blocks each having a thickness of 18 mm were used. Four compound blocks were placed on the outer periphery of the protective layer 5 (outer diameter 108 mm) in the circumferential direction of the protective layer 5 to form a compound portion 7 with a thickness of 18 mm (finished outer diameter 144 mm). Thereafter, a metal tube 9 (inner diameter 148 mm) was installed around the outer periphery of the compound section 7. The clearance c was 2 mm, which was 1.4% of the inner diameter of the metal tube. In this way, the cable intermediate connection structure was assembled.

(Example 3)
Regarding Example 1, a cable intermediate connection structure was assembled in the same manner as in Example 1, except that the configuration of the compound section was changed from a compound sheet to a cylindrical compound block. Specifically, a cylindrical compound block having a thickness of 18 mm and having one notch provided throughout the lengthwise direction was used. A cylindrical compound block was attached to the outer periphery of the protective layer 5 (outer diameter 108 mm) to form a compound portion 7 with a thickness of 18 mm (finished outer diameter 144 mm). Thereafter, a metal tube 9 (inner diameter 148 mm) was installed around the outer periphery of the compound section 7. The clearance c was 2 mm, which was 1.4% of the inner diameter of the metal tube. In this way, the cable intermediate connection structure was assembled.

The following measurements were performed on the cable intermediate connection structures assembled in Examples 1 to 3 and Comparative Examples 1 to 2. The results are shown in Table 1.

[Assembly time]
The assembly time of the cable intermediate connection structure was measured.

[Rubber unit outer surface temperature]
As a conduction evaluation of the cable intermediate connection structure, calculate the maximum conductor temperature inside the cable intermediate connection structure when a current is applied to the power cable and the temperature of the cable conductor far away (4 m or more) from the conductor connection reaches 90℃. The surface temperature of the outer periphery of the rubber unit 3 was measured. The position of the outer periphery at which the surface temperature of the rubber unit 3 was measured was outside the joint between the cable conductors.

As shown in Table 1, in Examples 1 to 3, compared to Comparative Example 2 in which a liquid compound was injected, the assembly time was significantly shortened and variations in the temperature of the outer peripheral surface of the rubber unit were suppressed. In particular, compared to Example 1, the assembly time of Example 2 using a plurality of compound blocks was even shorter, and the assembly time of Example 3 using a cylindrical compound block was the shortest. The maximum conductor temperature inside the cable intermediate connection structure differs by about 2°C between Examples 1 to 3 and Comparative Example 2, which is the same as the temperature at the far end of the conductor connection, and the insulation performance inside the rubber unit is maintained. It had been.

On the other hand, in Comparative Example 2 in which a liquid compound was injected, the assembly time was extremely long due to the injection of the compound and the curing of the compound. Furthermore, since the filling state of the compound portion was extremely non-uniform, a large temperature variation of 8° C. occurred on the outer circumferential surface of the rubber unit. In addition, in Comparative Example 1, which does not include a compound part, there is no diffusion of heat from the rubber unit to the compound part, so the maximum conductor temperature inside the cable intermediate connection structure is as high as 101 °C, and even on the surface of the rubber unit it is 89 °C. There is also concern about deterioration in insulation performance.

1 Cable intermediate connection structure 2 Conductor connection part 3 Rubber unit 4 Shielding layer 5 Protective layer 6 Adhesive layer 7 Compound part 7a to 7d Compound block 7e Compound sheet 7f Cylindrical compound block 8 Low friction layer 9 Metal tube 9a First metal member 9b Second metal member 10a First power cable 10b Second power cable 11a First cable conductor 11b Second cable conductor 12a First cable insulator 12b Second cable insulator 13a First outer semiconducting layer 13b Second outer semiconducting layer 14a First semiconductive tape layer 14b Second semiconductive tape layer 15a First cable shielding layer 15b Second cable shielding layer 16a First cable sheath 16b Second cable sheath 31 Main insulation part 32 Inner semiconductive part 33 End half Conductive portion 34 Outer semi-conductive portion 35 Semi-conductive tape portion 36 Pedestal spacer 71 Notch portion 72a First dividing surface 72b Second dividing surface 91 Recessed portion 92 Seal member 93 Hole 94 Bolt 95 Flange portion 96 Through hole 97 Bolt 100 Waterproof portion

Claims (7)

A cable intermediate connection structure that connects an end of a first power cable and an end of a second power cable,
a conductor connection portion connecting an end of a first cable conductor of the first power cable and an end of a second cable conductor of the second power cable;
a rubber unit that covers the outer periphery of the conductor connection portion;
a shielding layer covering the outer periphery of the rubber unit;
a protective layer covering the outer periphery of the shielding layer;
A plurality of compound blocks divided and arranged along the circumferential direction of the protective layer, a compound sheet wound around the outer periphery of the protective layer, and a cylindrical compound block arranged over the outer periphery of the protective layer. a resin compound part that includes at least one resin compound part and covers the outer periphery of the protective layer;
A cable intermediate connection structure comprising: a metal tube that covers the outer periphery of the compound portion. 2. The cable intermediate connection structure according to claim 1, wherein the cylindrical compound block includes one notch provided throughout the lengthwise direction, and the interval between the notches is expandable. Assuming that the finished outer diameter A of the compound part and the inner diameter B of the metal tube are the clearance c between the outer periphery of the compound part and the inner periphery of the metal tube as (B-A)/2, The cable intermediate connection structure according to claim 1 or 2, wherein the clearance c is 1.2% or more and 7.7% or less of the inner diameter B of the metal tube. The cable intermediate connection structure according to claim 1 or 2, further comprising an adhesive layer provided between the protective layer and the compound part. 3. The cable intermediate connection structure according to claim 1, wherein the compound portion has a Poisson's ratio of 0.48 or more and 0.50 or less. The cable intermediate connection structure according to claim 1 or 2, further comprising a low friction layer having a dynamic friction coefficient smaller than that of the compound part, between the compound part and the metal tube. 7. The cable intermediate connection structure according to claim 6, wherein the low friction layer is comprised of a low friction tape.

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