JPH06325625A - Submarine power cable - Google Patents

Abstract

PURPOSE:To provide a submarine power cable in which the crush of the cable caused by external pressure and the fatigue failure of a water-barrier layer and a corrosion resistant layer caused by internal pressure variation are prevented, and reinforcement and fatigue protection are applied. CONSTITUTION:In a submarine power cable in which an insulating layer 12, a water-barrier layer 14, a corrosion resistant layer 21, an armored layer 22, and a seating-on-bed layer 23 are formed on the radialy outwards of a cable conductor 11 in that order, a reinforcement shell layer 13 made of nonmagnetic stainless steel or FRP excellent in external pressure resistant strength and flexibility is arranged between the insulating layer 12 and the water-barrier layer 14. The reinforcement shell layer 13 is formed with a reinforcement tube obtained by spirally winding string with a Z-shaped cross section made of stainless steel, FRP and others, corrugated tube with a spiral or bellows-shaped corrugated part, or a reinforcement tube obtained by spirally winding string with a C-shaped cross section in two layers of an inner layer and an outer layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a submarine power cable laid in a deep water of 1000 m or more.

[0002]

2. Description of the Related Art Conventionally, for example, a high-voltage submarine power cable of 154 kV class or higher has a rubber on the conductor 1 as shown in FIG.
Insulating layer 2 made of plastic or the like, water blocking layer 3 made of lead or the like, anticorrosion layer 4 made of plastic and metal, armor 5 made of FRP
And a seat layer 6 are provided. This submarine power cable is laid on the seabed, but there is no example of laying it in deep water, and the actual results so far have been limited to 500 m.

[0003]

When the submarine power cable is laid in a large depth of water (1000 m or more), there are the following problems. The first problem is that when laying a seabed, when the cable is pulled into the sea from the laying ship, the external pressure applied to the side surface of the cable increases significantly, and the large water pressure (external pressure) due to the large water depth is also constantly applied to the cable. It means crushing. The second problem is that the water-impervious layer and the waterproof layer outside the insulating layer are fatigue-damaged by the internal pressure change due to the radial expansion and contraction of the insulating layer due to the change in the cable load.

[0004]

SUMMARY OF THE INVENTION The present invention provides a submarine power cable which prevents the cable from being crushed by the external pressure, and prevents the water-impervious layer and the anticorrosive layer from being damaged by fatigue due to a change in the internal pressure, and taking measures against strength and fatigue. In a submarine power cable comprising an insulating layer, a water shield layer, an anticorrosion layer, and armor on a cable conductor, a non-excellent external pressure resistance and slenderness is provided between the insulating layer and the water shield layer. It is characterized in that a magnetic reinforcing shell layer is provided.

[0005]

[Function] As described above, since the non-magnetic reinforcing shell layer having excellent resistance to external pressure and flexibility is provided between the insulating layer and the water-impervious layer, the cable external pressure is maintained while maintaining the cable flexibility. Prevents the cable from being crushed, and also prevents the water-impervious layer and the anticorrosive layer outside the insulating layer from being fatigue-damaged due to the change in internal pressure due to expansion and contraction of the insulating layer.

[0006]

1 to 4, a submarine power cable 10 according to an embodiment of the present invention will be described in detail. Reference numeral 11 is a cable conductor, and 12 is a cable conductor 11 and a cross-linked polyethylene 3 together with inner and outer semiconductor layers. Insulation layer formed by layer coextrusion coating, 13 is a reinforcing shell layer provided on the insulating layer 12, 14 is a water shield layer provided directly on the reinforcing shell layer 13 or via a cloth cushion tape layer, The reinforcing shell layer 13 is provided between the insulating layer 12 and the water shield layer 14.

The reinforcing shell layer 13 is composed of a non-magnetic reinforcing pipe 15, a reinforcing pipe 17, or a reinforcing pipe 18 which is excellent in pressure resistance and flexibility. As shown in FIG. 2, the reinforcing pipe 15 is made of stainless steel provided with hook edges 16c, 16d bent in a U shape so as to be point-symmetrical with respect to the center 16b of the bar on both side edges of a bar main body 16a having a Z-shaped cross section. A Z-shaped section 16 made of FRP or other non-magnetic material is spirally wound and adjacent hook edges 16c, 1
It is a pipe (interlock pipe) formed by engaging 6d with each other.

As shown in FIG. 3, the reinforcing tube 17 is a tube body 17a made of stainless steel, FRP or other non-magnetic material.
The corrugated pipe has a spiral or bellows-shaped corrugated portion 17b having a sine curve cross section, which is integrally formed with the pipe main body 17a and has no engaging engagement portion.

As shown in FIG. 4, the reinforcing tube 18 is made of stainless steel, FRP or other non-magnetic material, and has legs 1 on both side edges.
An inner layer 18a formed by spirally winding a cross-section C-shaped strip 19 having 9a, 19a and an opening 19b in the center so that the opening 19b is located outside and a minute gap is formed between the strips 19; On the inner layer 18a, the C-shaped cross section 1
9 so that the opening 19b is inside, and the opening 19b engages with the legs 19a, 19a of the adjacent turns of the section C-shaped section 19 in the inner layer 18a so as to engage with each other, and between the sections. The outer layer 18b is formed by spirally winding so as to form a gap.

The water-blocking layer 14 is formed by extrusion-coating pure lead or lead alloy on the reinforcing shell layer 13 through a cushion tape layer made of cloth, or by overlaying and bonding plastic and lead. It is provided by winding a lead laminate tape for water.

In FIG. 1, reference numeral 21 is an anticorrosion layer provided by extruding polyethylene on the water-impervious layer 14 through a cushion tape layer 20 made of cloth, and 22 is an anticorrosion layer 2.
A number of flat metal cross-section metal reinforcing strips on 1 inside and 2 layers outside,
Further, the armoring provided by spirally winding at a large pitch so that the spiral winding directions of the metal reinforcing strips are alternated (opposite) between the inner layer and the outer layer, and 23 is polyethylene coating on the armoring 22 or It is a seat floor layer provided by winding polypropylene yarn.

[0012]

As described above, according to the present invention, since the non-magnetic reinforcing shell layer excellent in external pressure resistance and flexibility is provided between the insulating layer and the water-impervious layer, the flexibility of the cable is improved. While maintaining the above, it is possible to prevent the cable from being crushed by the external pressure of the cable, and to prevent the water-impervious layer and the anticorrosive layer outside the insulating layer from being fatigue-fractured due to the change in the internal pressure of the insulating layer that expands and contracts.
Therefore, it is possible to lay submarine power cables in deep water.

[Brief description of drawings]

FIG. 1 is a perspective view showing a submarine power cable of the present invention.

FIG. 2 is an enlarged vertical sectional view showing a part of the reinforcing shell layer in FIG.

FIG. 3 is an enlarged vertical sectional view showing a part of another reinforcing shell layer.

FIG. 4 is an enlarged vertical sectional view showing a part of still another reinforcing shell layer.

FIG. 5 is a perspective view showing a conventional submarine power cable.

[Explanation of symbols]

 10 Submarine Power Cable 11 Cable Conductor 12 Insulating Layer 13 Reinforcement Shell Layer 14 Reinforcement Layer 15 Reinforcement Pipe 16 Cross Section Z-Shape 16a Article Main Body 16b Article Center 16c Hook Edge 16d Hook Edge 17 Reinforcement Pipe 17a Pipe Body 17b Corrugated Part 18 Reinforcement pipe 18a Inner layer 18b Outer layer 19 Cross-section C-shaped strip 19a Leg 19b Opening 20 Cloth cushion tape layer 21 Corrosion protection layer 22 Armor 23 Seat floor layer

Claims (4)

[Claims] 1. A submarine power cable comprising an insulating layer, a water shield layer, an anticorrosion layer and armor on a cable conductor, which is excellent in external pressure resistance and flexibility between the insulating layer and the water shield layer. A submarine power cable characterized by having a non-magnetic reinforcing shell layer. 2. A hook having a Z-shaped cross section, wherein the reinforcing shell layer is provided with hook edges at both side edges of a Z-shaped cross section so as to be point-symmetric with respect to the center of the thread, and is wound adjacent to each other. The submarine power cable according to claim 1, wherein the submarine power cable is a reinforcing pipe in which edges are engaged with each other and engaged with each other. 3. The seabed according to claim 1, wherein the reinforcing shell layer is a corrugated pipe having a spiral or bellows-shaped corrugated portion integrally formed with the pipe main body without an engaging engagement portion on the pipe wall of the pipe main body. Power cable. 4. The reinforcing shell layer is formed by spirally winding a C-shaped section having a leg on both side edges and an opening at the center with the opening outside and forming a minute gap between the sections. And a cross-section C of the cross-section C in the inner layer, the cross-section C-shaped strip being formed on the inner layer and having the opening inside.
To engage and engage the legs of adjacent turns of the strip,
The submarine power cable according to claim 1, wherein the submarine power cable is a reinforcing tube including an outer layer formed by spirally winding so that a minute gap is formed between the strips.