JP6754170B2 - Power cable and its manufacturing method - Google Patents

Description

The present invention relates to a power cable and a method for manufacturing the same, and in particular, a power cable using a split conductor such as a submarine laying cable, a floating underwater cable (riser cable), a DC and AC XLPE (cross-linked polyethylene) cable for high current transmission, and a power cable. Regarding the manufacturing method.

In general, for power cables with a large conductor cross-linked area such as submarine laying cables, floating underwater cables (riser cables), DC and AC XLPE (cross-linked polyethylene) cables for high-current transmission, use split conductors as the conductors. There are many.

The split conductor is manufactured by twisting a plurality of strands of copper or aluminum to form a fan shape by compression molding to form a segment conductor, and twisting a plurality of (usually 4 to 7) segment conductors. Will be done.

In the conventional power cable, in order to give the divided conductor an electrical insulation performance, a single wire is coated with an insulating material or an oxide film is formed (hereinafter, this technique is referred to as Conventional Example 1).

In other conventional power cables, in order to give the split conductor water-stopping performance and water-absorbing performance so that voids and water trees do not occur in the insulating layer, a tape having water-stopping performance and water-absorbing performance is used between the segment conductors. It was intervened (hereinafter, this technique is referred to as Conventional Example 2).

Patent Document 1 discloses a structure in which a water-stopping material such as rubber is inserted between wires to physically stop water in order to give water-stopping performance to a circular compressed conductor and a round-twisted conductor (hereinafter, This technique is called Conventional Example 3)

Patent Document 2 discloses a cross-linked polyethylene insulated power cable using a split conductor in which no inclusions are present (hereinafter, this technique is referred to as Conventional Example 4).
Japanese Unexamined Patent Publication No. 1-217803 Japanese Unexamined Patent Publication No. 9-106713

FIG. 4 is a cross-sectional view showing a wire insulating structure of Conventional Example 1 before being formed into a segment conductor. As shown in FIG. 4, in the wire insulation structure of the conventional example 1, the wires 50 that are not insulated and the wires 51 that are insulated are arranged so as not to be adjacent to each other. There is a problem that it is necessary to consider the amount of use and there is a risk of work mistakes.

Further, when arranging only with the insulated wires 51, there is a problem that not only the manufacturing cost is increased but also the lead time related to the manufacturing is lengthened and the productivity is lowered.

In the conventional example 2, there is a problem that it is difficult to use the tape having water-stopping performance and water-absorbing performance in an environment of high water pressure, for example, because the gap between the wires cannot be physically filled. ..

In the conventional example 3, since the water blocking material is used, there is a problem that the number of parts increases and the manufacturing cost increases.

Conventional Example 4 has a problem that it is difficult to use it in an environment of high water pressure, for example, because the gap between the strands cannot be physically filled.

The present invention has been made to solve the above problems, and has both electrical insulation performance and water blocking performance between wires, reduces work mistakes and manufacturing costs, improves productivity, and has high water pressure. It is an object of the present invention to provide a power cable and a manufacturing method thereof that can be used even in the above environment.

The method for manufacturing a power cable of the present invention is a method for manufacturing a power cable having a split conductor.
(1) A plurality of uninsulated strands having a circular cross section are bundled and twisted together, and a thermoplastic resin having electrical insulation is filled so as to cover the periphery to form a plurality of segment conductors. And the process to do
(2) A step of twisting the formed plurality of the segment conductors in a state where the thermoplastic resins are in contact with each other to form the divided conductor.
(3) A step of coating the divided conductor with an insulating layer and
Have,
The thermoplastic resin is softened at the temperature received when the insulating layer is coated, and the gaps between the strands are filled so that the strands have electrical insulation .
It is characterized by that.

After the step (1), there may be a step of compression molding the segment conductor into a substantially fan-shaped cross section.

According to the power cable of the present invention, since the wire-twisted body obtained by twisting a plurality of wires has a split conductor in which a thermoplastic resin having electrical insulation is filled to form a segment conductor, the thermoplastic resin can be used. By softening at a predetermined temperature, the gap between the wires can be filled, and both the electrical insulation performance and the water blocking performance between the wires can be obtained.

In addition, since it is possible to use only uninsulated wires, it is not necessary to consider the arrangement and amount of wires used, reducing work mistakes and manufacturing costs, and coating the wires alone with an insulating material. Since it is not necessary to form an oxide film, the lead time for manufacturing can be shortened and the productivity can be improved.

Further, since the wires can be filled with the thermoplastic resin without gaps, it can be used in a wide range of applications such as in a high water pressure environment.

According to the method for manufacturing a power cable according to an embodiment of the present invention, it is possible to provide a power cable that exhibits the above effects, and at the same time, the thermoplastic resin filled in the divided conductor is softened at the temperature received when the insulating layer is coated. The coating step of the insulating layer and the softening step of the thermoplastic resin can be performed at the same time, and the productivity can be improved.

It is sectional drawing which shows the structure of the power cable which concerns on embodiment of this invention. (A) to (C) are explanatory views for explaining the manufacturing method of the electric power cable which concerns on embodiment of this invention. It is explanatory drawing for demonstrating the molding machine which compression-molds the wire-twisted body of a segment conductor into a fan shape. It is sectional drawing which shows the wire insulation structure of the prior art example 1 before being formed into a segment conductor.

Hereinafter, embodiments of the present invention will be described. FIG. 1 is a cross-sectional view showing the structure of a power cable according to an embodiment of the present invention.

As shown in FIG. 1, the power cable 1 according to the embodiment of the present invention includes a submarine laying cable, a floating underwater cable (riser cable), a DC and AC XLPE (cross-linked polyethylene) cable for high current transmission, and the like. It is a power cable having a split conductor 2.

The split conductor 2 is a plurality of 4 to 7 conductors formed by filling a wire-twisted body 4 in which a wire wire 3 made of a plurality of copper or aluminum or the like is twisted with a thermoplastic resin 5 having electrical insulation. It is formed by twisting (four in FIG. 1) segment conductors 6.

The thermoplastic resin 5 is preferably elastic because it needs to be bent during handling between manufacturing processes and transportation to the site, and for example, a thermoplastic elastomer is preferable. There are styrene type, olefin type, vinyl chloride type, urethane type, amide type and the like, but the present invention is not particularly limited.

The thermoplastic resin 5 filled in the divided conductor 2 is softened at a predetermined temperature, whereby the gap between the strands 3 is filled.

The inner semi-conductive layer 7 is coated on the divided conductor 2, and the insulating layer 8 made of cross-linked polyethylene is coated on the inner semi-conductive layer 7. The insulating layer 8 is coated with an external semi-conductive layer 9 made of a semi-conductive resin, a semi-conductive cloth tape, or the like, and the outer semi-conductive layer 9 is coated with a metal shielding layer 10 made of a copper tape or the like. ing. Further, the metal shielding layer 10 is coated with an anticorrosion layer 11 made of a vinyl chloride resin.

2 (A) to 2 (C) are explanatory views for explaining the manufacturing method of the power cable 1 according to the embodiment of the present invention.

First, the strands 4 in which a plurality of strands 3 are twisted are filled with a thermoplastic resin 5 having electrical insulation to form a segment conductor 6 (see FIG. 2 (A)). The thermoplastic resin 5 is put into the wire-twisted body 4 in a solid state such as a tape or a string so that it can be easily handled.

Next, for example, the segment conductor 6 is compression-molded into a substantially fan-shaped cross section by the molding machine 12 shown in FIG. 3 (see FIG. 2 (B)).

FIG. 3 is an explanatory diagram for explaining a molding machine that compression-molds the strands of the segment conductors 4 into a fan shape.

As shown in FIG. 3, the molding machine 12 includes a pair of molding rolls 13 and 14. A V-shaped concave groove 13a is formed on the outer peripheral surface of one molding roll 13, and an arc-shaped concave groove 14a that is gently curved and recessed inward is formed on the outer peripheral surface of the other molding roll 14. The rotating shafts 13b and 14b of the molding rolls 13 and 14 are parallel to each other and are combined so that the outer peripheral surfaces of the molding rolls 13b and 14b are in contact with each other to form a fan-shaped molding hole 15 by the concave grooves 13a and 14a. Rotate (rotate, revolve) around the central axis of 13b, 14b and the molding hole 15 in the direction of the arrow. The rotation (revolution) of the forming rolls 13 and 14 at least around the forming hole 15 is performed by driving a drive source (not shown) such as a motor.

A segment conductor 6 having a substantially circular cross section is inserted into the forming holes 15 of the forming rolls 13 and 14 of the forming machine 12, and a compressive force is applied from the forming rolls 13 and 14 inward in the radial direction to form the forming rolls 13 and 14. It is compression-molded into a fan shape as it rotates (rotates).

Next, a plurality of molded segment conductors 6 (4 in FIG. 2) are twisted to form a split conductor 2 having a substantially circular cross section (see FIG. 2C).

After that, the inner semi-conductive layer 7 is coated on the divided conductor 2, and the insulating layer 8 made of cross-linked polyethylene is coated on the inner semi-conductive layer 7.

Next, the insulating layer 8 is coated with an external semi-conductive layer 9 made of a semi-conductive resin, a semi-conductive cloth tape, or the like, and the outer semi-conductive layer 9 is coated with a metal shielding layer 10 made of a copper tape or the like. Further, the anticorrosion layer 11 made of vinyl chloride resin is coated on the metal shielding layer 10.

The thermoplastic resin 5 filled in the divided conductor 2 is softened at the temperature (about 150 ° C.) received when the insulating layer 8 is coated, thereby filling the gap between the strands 3.

Through the above steps, the power cable 1 according to the embodiment of the present invention is manufactured.

According to the power cable 1 according to the embodiment of the present invention, the strands 4 obtained by twisting a plurality of strands 3 are filled with a thermoplastic resin 5 having electrical insulation to form a segment conductor 6. Since it has the split conductor 2, it is possible to fill the gap between the strands 3 by softening the thermoplastic resin 5 at a predetermined temperature, and it is possible to have both the electrical insulation performance and the water blocking performance between the strands 3. it can.

Further, since only the uninsulated wire 3 can be used, it is not necessary to consider the arrangement and the amount of the wire 3, work mistakes and manufacturing costs are reduced, and the wire itself is coated with an insulating material. Since it is not necessary to form an oxide film or to form an oxide film, the lead time for manufacturing can be shortened and the productivity can be improved.

Further, since the wires 3 can be filled with the thermoplastic resin 5 without gaps, it can be used in a wide range of applications such as in an environment of high water pressure.

According to the method for manufacturing the power cable 1 according to the embodiment of the present invention, it is possible to provide a power cable having the above effect, and at the temperature received when the inner semiconductive layer 7, the insulating layer 8 and the outer semiconductive layer 9 are coated. Since the thermoplastic resin 5 filled in the divided conductor 2 is softened, the coating step of the insulating layer 8 and the softening step of the thermoplastic resin 5 can be performed at the same time, and the productivity can be improved.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the technical matters described in the claims.

The power cable of the present invention and its manufacturing method are used for those having a split conductor such as a submarine laying cable, a floating underwater cable (riser cable), a DC and AC XLPE (cross-linked polyethylene) cable for high current transmission, and the like. Ru.

1: Power cable 2: Divided conductor 3: Wire 4: Wire twisted 5: Thermoplastic resin 6: Segment conductor 7: Internal semi-conductive layer 8: Insulation layer 9: External semi-conductive layer 10: Metal shielding layer 11: Anticorrosion layer 12: Molding machine 13: Molding roll 14: Molding roll 15: Molding hole

Claims (2)

In the method of manufacturing a power cable having a split conductor
(1) A plurality of uninsulated strands having a circular cross section are bundled and twisted together, and a thermoplastic resin having electrical insulation is filled so as to cover the periphery to form a plurality of segment conductors. And the process to do
(2) A step of twisting the formed plurality of the segment conductors in a state where the thermoplastic resins are in contact with each other to form the divided conductor.
(3) A step of coating the divided conductor with an insulating layer and
Have,
The thermoplastic resin is softened at the temperature received when the insulating layer is coated, and the gaps between the strands are filled so that the strands have electrical insulation.
A method of manufacturing a power cable, which is characterized in that. After the step (1), there is a step of compression molding the segment conductor into a substantially fan-shaped cross section.
The method for manufacturing a power cable according to claim 1 , wherein the power cable is manufactured.

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