JP2019179593A - 3-core sea bottom power cable - Google Patents

Abstract

To provide a 3-core sea bottom power cable that can suppress AC loss, is resistant to twisting, and can prevent large size.SOLUTION: Provided is a 3-core sea bottom power cable 1 comprising three cable cores 2 and an outer layer 3 enclosing three cable cores 2, and in which one or more non-metallic tensile-strength members 4 are arranged in regions A and B between the three cable cores 2 and the outer layer 3, and the outer layer 3 is covered with a non-metallic sheath 5.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a three-core submarine power cable used in the seabed, the sea, and other water.

Three-core submarine power cables used under the sea, in the sea, and other underwater have a strength body that can withstand the tension applied when laying from a ship or lifting a cable, and are used when sending out the cable. It must be able to withstand the side pressure of the caterpillar.
Therefore, the conventional three-core submarine power cable 100 is arranged so that the three-core cable core 101 is in a triangular state, for example, as shown in FIG. A layer 102, a floor layer 103, an armor 104 as a strength member, a protective layer 105, and the like, and an intervening portion 106 made of yarn, string, etc. is provided between the three-core cable core 101 and the outer layer 102. Was configured to be.

However, if the cable is bent, twisted, or subjected to a load, the armor 104 is stressed and the cable core 101 is also stressed. It has been proposed to arrange a metal twisted wire as a tensile body.
In addition, since iron wire is used for the conventional armor 104 and is heavy and the handling of the cable is poor, Patent Document 2 proposes to reduce the weight by replacing the iron wire with a reinforced plastic filament. Yes.

Further, in the above conventional structure, the armor 104 is arranged by loosely twisting a plurality of iron wires around the cable core 101, but the direction in which the twist is applied to the cable and the iron wire is untwisted. When a force is applied to the wire, the tensile strength function of the iron wire, that is, the armor 104 is lowered.
Therefore, in Patent Document 3, two layers of armor are provided, and the twisting direction is reversed in each layer, so that the tensile strength function of the armor can be maintained even if a force is applied to the cable in the twisting direction. Proposed.

JP 58-135514 A JP-A-1-274321 JP 2009-199847 A

  However, in the conventional three-core submarine power cable 100 and the cable described in Patent Document 1, when AC current is transmitted through the cable core, an iron wire of the armor 104, a rectangular metal strip, or a metal stranded wire inside the cable is used. AC loss occurs, and the transmission capacity is reduced by this loss. Further, in order to maintain the power transmission capacity, the size of the conductor in the cable core must be increased. However, this increases the size of the cable, which increases the cost required for manufacturing, transporting, and laying the cable.

In the cable described in Patent Document 2, when a force is applied to the cable in the twisting direction and a force is applied in the direction in which the reinforced plastic filament is untwisted, the tensile strength function of the reinforced plastic filament is reduced.
The cable described in Patent Document 3 is strong in the torsional force, but the size of the cable is increased by the amount of armoring in two layers, and in the same manner as described above, the cable is manufactured, transported and laid. There has been a problem that the cost required for such increases.

  The present invention has been made in view of the above problems, and provides a three-core submarine power cable that can suppress AC loss, is resistant to twisting, and can prevent an increase in size. For the purpose.

In order to solve the above-mentioned problem, the invention according to claim 1
In a three-core submarine power cable comprising three cable cores and an outer layer enclosing the three cable cores,
One or a plurality of non-metallic strength members are arranged in a region between the three cable cores and the outer layer,
The outer layer is covered with a non-metallic sheath.

  According to a second aspect of the present invention, in the three-core submarine power cable according to the first aspect, an armor made of a plurality of non-metallic linear bodies is provided between the outer layer and the sheath. It is characterized by that.

  According to a third aspect of the present invention, in the three-core submarine power cable according to the first or second aspect, the tensile body includes an area surrounded by the three cable cores, the two cable cores, One is arranged in each of a plurality of areas out of the areas surrounded by the outer layer.

  According to a fourth aspect of the present invention, in the three-core submarine power cable according to the first or second aspect, the tensile body includes an area surrounded by the three cable cores, and the two cable cores. A plurality of regions are arranged in one or a plurality of regions out of the regions surrounded by the outer layer.

  The invention according to claim 5 is the three-core submarine power cable according to claim 4, wherein the plurality of strength members arranged in the same region are not twisted with each other.

  The invention according to claim 6 is the three-core submarine power cable according to claim 1 or 2, wherein a spacer is disposed in a region surrounded by the two cable cores and the outer layer, One or a plurality of the strength members are fixed to the spacer and arranged.

  The invention according to claim 7 is the three-core submarine power cable according to claim 6, wherein an optical fiber is arranged in a tube fixed to the spacer.

  According to the present invention, one or a plurality of non-metallic strength members are arranged in a region between three cable cores and an outer layer of a three-core submarine power cable, and the outer layer is covered with a non-metallic sheath. Therefore, it is possible to suppress AC loss, tolerate torsion, and to prevent an increase in size.

It is sectional drawing which shows a cross section perpendicular | vertical to the cable longitudinal direction of the 3-core submarine power cable which concerns on 1st Embodiment. It is sectional drawing which shows a cross section perpendicular | vertical to the cable longitudinal direction of the 3-core submarine electric power cable which concerns on 2nd Embodiment. It is sectional drawing which shows a cross section perpendicular | vertical to the cable longitudinal direction of the 3-core submarine electric power cable which concerns on 3rd Embodiment. It is sectional drawing which shows a cross section perpendicular | vertical to the cable longitudinal direction of the 3-core submarine power cable which concerns on 4th Embodiment. It is sectional drawing which shows a cross section perpendicular | vertical to the cable longitudinal direction of the conventional 3 core submarine power cable.

  Hereinafter, the three-core submarine power cable according to the present embodiment will be described with reference to the drawings. However, each embodiment described below is provided with various technically preferable limitations for carrying out the present invention. However, the scope of the present invention is not limited to the following embodiments and illustrated examples. .

[First Embodiment]
FIG. 1 is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of the three-core submarine power cable according to the first embodiment.
The three-core submarine power cable 1 is arranged in a region between the three cable cores 2, the outer layer 3 containing these three cable cores 2, and the three cable cores 2 and the outer layer 3. A tensile body 4 and a sheath 5 covering the outer layer 3 are provided.

Each cable core 2 includes a conductor 21 at the center, and is formed of an inner semiconductive layer 22, an insulating layer 23, an outer semiconductive layer 24, a lead coating 25, an anticorrosion layer 26, and the like in order from the conductor 21 to the outside. ing. Although FIG. 1 shows a case where the conductor 21 of the cable core 2 is formed of five divided conductor segments, the conductor 21 may be an integral structure instead of such a divided conductor structure.
The three cable cores 2 have the same outer diameter, and are arranged so that each cable core 2 is in contact with the other two cable cores 2. That is, each cable core 2 is arranged so that the centers of the three cable cores 2 viewed from the cable longitudinal direction are located at the apexes of the equilateral triangle. Each cable core 2 is loosely twisted in the outer layer 3.

The outer layer 3 is made of a resin such as polyethylene, for example, and partitions the inside of the cable in which the three cable cores 2 and the like are present from the outside of the cable. The outer layer 3 has a circular cross section, and is in contact with the three cable cores 2 on the inner peripheral surface thereof.
Further, one or a plurality of strength members 4 are arranged in a region between the three cable cores 2 and the outer layer 3. A portion other than the strength member 4 in this region is filled with a thin PP (polypropylene) yarn 6.

The strength member 4 is a solid wire. It is made of non-metal and can be formed of carbon fiber, fiber reinforced plastic (FRP, particularly glass fiber reinforced plastic (GFRP)), aramid fiber, or the like.
Further, when the three-core submarine power cable 1 is used in a place where the water depth is shallow, it can be formed of polyolefin-based or polyester-based resin fibers. In addition, the material, the number, and the like of the strength members 4 arranged in the three-core submarine power cable 1 are appropriately determined according to the situation where the three-core submarine power cable 1 is used.

For example, only one tensile body 4 is arranged in a central area A of the cable surrounded by the three cable cores 2 or a substantially sector-shaped area B surrounded by the two cable cores 2 and the outer layer 3. Alternatively, as shown in FIG. 1, a plurality of strength members 4 may be arranged in each of the cable center region A and each of the substantially sector-shaped regions B.
The tensile body 4 may be disposed so as to contact the two cable cores 2, or may be disposed so as to contact only one cable core 2, so as not to contact any cable core 2. May be arranged. The tensile body 4 is loosely twisted in the outer layer 3 in accordance with the twist of each cable core 2.

The sheath 5 covering the outer layer 3 protects the outer layer 3 and the cable core 2 and the like. It is made of non-metal and is made of a polyolefin resin such as polyethylene or polypropylene. In addition, it does not necessarily need to be polyolefin type.
The sheath 5 is formed integrally with the outer layer 3 by extruding these resins.

[Manufacture of 3-core submarine power cable]
Next, the manufacture of the three-core submarine power cable 1 according to this embodiment will be described.
First, the three cable cores 2 are loosely twisted and bundled so that each cable core 2 is in contact with the other two cable cores 2. At that time, one or a plurality of strength members 4 are arranged at predetermined positions and twisted together with the three cable cores 2.

In addition, the PP yarns 6 are arranged in the gaps between the cable cores 2 and the strength members 4 and twisted together, and the outer layer 3 is formed by wrapping tape around the cable cores 2, the strength members 4 and the PP yarns 6. Form and fix them. Then, the sheath 5 that covers the outer layer 3 is integrally formed with the outer layer 3 by extrusion molding so that the resin is disposed on the outer periphery thereof.
In this way, the three-core submarine power cable 1 is manufactured.

[Effects of 3-core submarine power cable according to this embodiment]
In the present embodiment, the three-core submarine power cable 1 is formed as described above. Therefore, the tensile body 4 can effectively withstand the tension applied to the three-core submarine power cable 1. This point will be specifically described in an embodiment described later.
Further, the three-core submarine power cable 1 does not have an armor made of iron wire or the like, and the strength member 4 and the sheath 5 are both made of non-metal.

Therefore, when alternating current is transmitted by the three-core submarine power cable 1, no AC loss occurs in the armor 104 unlike the conventional three-core submarine power cable 100 (see FIG. 5), and at least the tensile member 4 And the sheath 5 does not cause AC loss.
Therefore, in the three-core submarine power cable 1 according to the present embodiment, AC loss can be suppressed, and the transmission capacity is hardly reduced. Therefore, it is not necessary to increase the size of the conductor 21 of the cable core 2 in order to maintain the power transmission capacity, and it is possible to prevent the size of the three-core submarine power cable 1 from being increased.

Further, in the three-core submarine power cable 1 according to the present embodiment, the sheath 5 provided at the outermost part of the cable covers the outer layer 3 and is integrally formed with the outer layer 3 and is not twisted. .
In the conventional armor of the three-core submarine power cable 100 and the twisted flat metal strip or reinforced plastic filament of the cable described in Patent Documents 1 and 2, when force is applied in the direction of untwisting Although the function is deteriorated, such a situation does not occur in the sheath 5 of the present embodiment, and the sheath 5 protects the cable core 2 and the like even if a force is applied to the three-core submarine power cable 1 in the twisting direction. Will not be lost.
Therefore, the three-core submarine power cable 1 according to the present embodiment is resistant to twisting.

Further, in the three-core submarine power cable 1 according to the present embodiment, by providing the sheath 5 that covers the outer layer 3 and is integrally formed with the outer layer 3 as described above, it becomes strong against twisting. Therefore, it is not necessary to provide two layers of armor like the cable described in Patent Document 3, and it is not necessary to increase the size of the cable.
As described above, in the three-core submarine power cable 1 according to the present embodiment, it is possible to prevent the cable from becoming large, and it is possible to accurately increase the cost required for manufacturing, transporting, and laying the cable. It becomes possible to prevent.

[Example]
For example, when the cable weight M per unit length of the three-core submarine power cable 1 is 100 [kg / m] and the cable outer diameter r is 200 mm, the underwater weight W (= M−π × (r / 2 ) ² × 0.001) is 68.58 [kg / m]. If the 3-core submarine power cable 1 is used at a water depth of 100 [m], the required tension Ts (= s × W × h × 9.8 [N / kg]) is 20 if the safety factor s is 3. .16 × 10 ⁴ [N].

On the other hand, when the diameter a of the strength member 4 of the three-core submarine power cable 1 is 8 [mm], the cross-sectional area A is 50.27 [mm ² ], and the number of strength members 4 is four (see FIG. 1). ), The total cross-sectional area At is 201 [mm ² ]. If the tensile body 4 is made of carbon fiber, the allowable tension F is 150 [kg / mm ² ], and therefore the allowable tension (design tension) of the three-core submarine power cable 1 by the four tensile bodies 4. T (= F × At × 9.8) is 29.56 × 10 ⁴ [N], and it can be said that the four strength members 4 have sufficient strength.

In the above embodiment, an armor made of a plurality of non-metallic filaments is provided between the outer layer 3 enclosing the three cable cores 2 and the sheath 5 so as to give an impact from the outside. You may improve the intensity | strength with respect to. At that time, a floor layer is provided around the outer layer 3 including the three cable cores 2 in the same manner as the above-described conventional three-core submarine power cable, and the outer layer 3 is made of a non-metallic linear body. It can be configured to provide armor (see 104 in FIG. 5).
In addition, about the said linear body, you may use the same material as a tension body, or a different material. In addition, since the tensile body 4 is provided inside the cable (PP yarn 6 or spacer 7), the linear body constituting the armor is the same as the linear body constituting the tensile body 4 and the thickness (or cross-sectional area). ) May be the same, or smaller ones may be used. By doing so, it is possible to obtain a three-core submarine power cable that is more resistant to external impacts and the like without causing an AC loss while suppressing an increase in size.

[Second Embodiment]
FIG. 2 is a cross-sectional view showing a cross section perpendicular to the cable longitudinal direction of the three-core submarine power cable according to the second embodiment.
For example, the tensile body 4 may be one of a region A at the center of the cable surrounded by the three cable cores 2 and a region B of a substantially fan shape surrounded by the two cable cores 2 and the outer layer 3. It is also possible to configure a plurality of areas in a plurality of areas.
Even if comprised in this way, like the case of 1st Embodiment, it is possible to suppress an alternating current loss, it is strong also to a twist, and the beneficial effect that it becomes possible to prevent enlargement is effective. It becomes possible to play.

In this case, if a plurality of strength members 4 arranged in the same region are twisted with each other, when the strength member 4 is tensioned, the strength member 4 is stretched and the strength is killed. End up.
Therefore, it is desirable that the plurality of strength members 4 arranged in the same region are not twisted with each other.

[Third Embodiment]
FIG. 3 is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of the three-core submarine power cable according to the third embodiment.
When the cable core 2 and the strength member 4 are in contact, when a strong tension is applied to the strength body 4, a strong force is applied from the strength body 4 to the cable core 2, which may adversely affect the cable core 2.

Therefore, in order to prevent such a situation from occurring, as shown in FIG. 3 instead of filling the substantially fan-shaped region B surrounded by the two cable cores 2 and the outer layer 3 with the PP yarn 6. It is possible to arrange the spacers 7 in such a manner that one or a plurality of strength members 4 are fixed by the spacers 7 and arranged. The spacer 7 is formed of a resin such as polyethylene or polypropylene, for example.
In addition, it is also possible to arrange a spacer in a region A in the center of the cable surrounded by the three cable cores 2 and to arrange one or a plurality of strength members 4 fixed by the spacer.

By configuring in this way, as in the case of the first embodiment and the second embodiment, it is possible to suppress AC loss, tolerate torsion, and to prevent an increase in size. It is possible to achieve a beneficial effect such as.
In addition, even when a strong tension is applied to the strength member 4, no force is directly applied from the strength member 4 to the cable core 2, so that it is possible to accurately prevent adverse effects on the strength cable core 2. .

[Fourth Embodiment]
FIG. 4 is a cross-sectional view showing a cross section perpendicular to the cable longitudinal direction of the three-core submarine power cable according to the fourth embodiment.
There are cases where an optical cable is inserted into the three-core submarine power cable 1.
In such a case, for example, as shown in FIG. 4, it is possible to provide a tube 8 in the spacer 7 and arrange the optical fiber 9 in the tube 8.

Although FIG. 4 shows the case where the optical fiber 9 is disposed so as to be located outside the tensile body 4, the optical fiber 9 may be configured to be disposed inside the tensile body 4.
In addition, a spacer is arranged in the area A in the center of the cable surrounded by the three cable cores 2, or a spacer is arranged in both the area A and the area B, and the optical fiber 9 is arranged by providing the pipe 8 in the spacer. It is also possible to configure.

If comprised in this way, like the case of the 1st-3rd embodiment, it is possible to suppress an alternating current loss, it is strong also to a twist, and it is useful effect that it becomes possible to prevent enlargement. It becomes possible to play.
Further, even when a strong tension is applied to the strength member 4, the optical fiber 9 does not receive a force from the strength member 4, and it is possible to accurately prevent the left fiber 9 from being adversely affected.

Needless to say, the present invention is not limited to the above embodiments and the like, and can be appropriately changed without departing from the gist of the present invention.
For example, the strength member 4 may be configured to be formed by coating a non-metallic core wire with another non-metallic material, and the strength member 4 may have a strength performance. What is necessary is not limited to a specific thing.
Also, the outer layer 3 and the sheath 5 can be configured by laminating a plurality of layers.

DESCRIPTION OF SYMBOLS 1 3 core submarine power cable 2 Cable core 3 Outer layer 4 Strength body 5 Sheath 7 Spacer 8 Tube 9 Optical fiber A Cable center area (area surrounded by three cable cores)
B Substantially fan-shaped area (area surrounded by two cable cores and outer layer)

Claims (7)

In a three-core submarine power cable comprising three cable cores and an outer layer enclosing the three cable cores,
One or a plurality of non-metallic strength members are arranged in a region between the three cable cores and the outer layer,
A three-core submarine power cable, wherein the outer layer is covered with a non-metallic sheath.   The three-core submarine power cable according to claim 1, wherein an armor made of a plurality of non-metallic filaments is provided between the outer layer and the sheath.   The strength members are arranged one by one in a plurality of regions of a region surrounded by the three cable cores and a region surrounded by the two cable cores and the outer layer. The three-core submarine power cable according to claim 1 or 2, characterized by the above.   A plurality of the tensile bodies are arranged in a single region or a plurality of regions out of a region surrounded by the three cable cores and a region surrounded by the two cable cores and the outer layer. The three-core submarine power cable according to claim 1 or 2, characterized by the above.   The three-core submarine power cable according to claim 4, wherein the plurality of strength members disposed in the same region are not twisted with each other.   2. A spacer is disposed in a region surrounded by the two cable cores and the outer layer, and one or a plurality of the tension members are fixed and disposed on the spacer. Alternatively, a three-core submarine power cable according to claim 2.   The three-core submarine power cable according to claim 6, wherein an optical fiber is disposed in a pipe fixed to the spacer.

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