ARMOURED SUBMARINE POWER CABLE

Abstract

A submarine power cable including: a first conductor, a first insulation system provided around the first conductor, and a plurality of elongated armour elements forming an armour layer surrounding the first insulation system, wherein each elongated armour element is made of a plurality of individual wires that are stranded, wherein at least some of the individual wires include metal.

Claims

1. An AC submarine power cable comprising: a first conductor, a first insulation system provided around the first conductor, and a plurality of elongated armour elements forming an armour layer surrounding the first insulation system, wherein each elongated armour element is made of a plurality of individual wires that are stranded, wherein at least some of the individual wires comprise metal, and wherein each individual wire of the elongated armour elements is covered with bitumen.

2. The AC submarine power cable as claimed in claim 1, wherein the metal is mild steel.

3. The AC submarine power cable as claimed in claim 1, wherein the metal is stainless steel.

4. The AC submarine power cable as claimed in claim 1, wherein each elongated armour element is a wire rope.

5. The AC submarine power cable as claimed in claim 1, wherein a diameter of each elongated armour element is in the range of 4-8 mm, such as 5-6 mm.

6. The AC submarine power cable as claimed in claim 1, wherein for at least one of the elongated armour elements all individual wires have the same diameter.

7. The AC submarine power cable as claimed in claim 1, wherein at least one of the elongated armour elements includes a central individual wire and six individual wires wound around the central individual wire.

8. The AC submarine power cable as claimed in claim 1, wherein the elongated armour elements are arranged helically along an axial direction of the submarine power cable.

9. The AC submarine power cable as claimed in claim 1, comprising a first water barrier arranged between the first insulation layer and the armour layer.

10. The AC submarine power cable as claimed in claim 9, wherein the first water barrier comprises a metallic sheath.

11. The AC submarine power cable as claimed in claim 9, wherein the first water barrier comprises a polymer sheath.

12. The AC submarine power cable as claimed in claim 1, wherein the first conductor and the first insulation system form part of a first power core wherein the submarine power cable comprises: a second power core including: a second conductor, and a second insulation system provided around the second conductor; and a third power core including: a third conductor, and a third insulation system provided around the third conductor; wherein the first power core, the second power core and the third power core form a stranded multi-core, and wherein the armour layer surrounds the stranded multi-core.

13. The AC submarine power cable as claimed in claim 1, comprising a corrosion protection layer provided on the elongated armour elements.

14. The AC submarine power cable as claimed in claim 13, wherein the corrosion protection layer comprises bitumen.

15. The AC submarine power cable as claimed in claim 14, wherein each elongated armour element is covered with the bitumen around its entire circumference.

16. (canceled)

17. The AC submarine power cable as claimed in claim 1, wherein each individual wire is in direct contact with bitumen around its entire perimeter surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The specific embodiments of the inventive concept will now be described, by way of example, with reference to the accompanying drawings, in which:

[0040] FIG. 1 shows a cross-section of an example of a submarine power cable;

[0041] FIG. 2 shows an example of an elongated armour element; and

[0042] FIG. 3 depicts a cross-section of another example of a submarine power cable.

DETAILED DESCRIPTION

[0043] The inventive concept will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplifying embodiments are shown. The inventive concept may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the inventive concept to those skilled in the art. Like numbers refer to like elements throughout the description.

[0044] FIG. 1 shows a cross-sectional view of an example of a submarine power cable 1. The submarine power cable 1 is a single core power cable.

[0045] The submarine power cable 1 comprises a first conductor 3.

[0046] The submarine power cable 1 comprises a first insulation system 5 arranged around the first conductor 3.

[0047] The first insulation system 5 may comprise an inner semiconductive layer 5a. The inner semiconductive layer 5a is a conductor screen. The inner semiconductive layer 5a is arranged around the first conductor 3.

[0048] The first insulation system 5 may comprise an insulation layer 5b. The insulation layer 5b is arranged around the inner semiconductive layer 5a. The insulation layer 5b may for example comprise cross-linked polyethylene (XLPE), impregnated paper tapes, or polypropylene.

[0049] The first insulation system 5 may comprise an outer semiconductive layer 5c. The outer semiconductive layer 5c is an insulation screen. The outer semiconductive layer 5c is arranged around the insulation layer 5b.

[0050] The submarine power cable 1 may comprise a water barrier 7. The water barrier 7 may be arranged around the outer semiconductive layer 5c. The water barrier 7 may for example comprise a metallic sheath. The metallic sheath may for example comprise copper, stainless steel, or aluminium. The metallic sheath may for example be one or more metal sheets that is/are folded around the insulation system 5 and longitudinally welded along the length of the submarine power cable 1.

[0051] The water barrier 7 may comprise a polymer sheath. The water barrier 7 may comprise the polymer sheath instead of the metallic sheath. Alternatively, the water barrier 7 may comprise the metallic sheath and a polymer sheath arranged around the metallic sheath. The polymer sheath may comprise a semiconductive polymer material. For example, the polymer sheath may comprise carbon black. The water barrier 7 may comprise an adhesive arranged between the metallic sheath and the polymer sheath so that the polymer sheath adheres to the metallic sheath. The adhesive may be a semiconductive adhesive in case the polymer sheath comprises a semiconductive polymer material.

[0052] The submarine power cable 1 comprises a plurality of elongated armour elements 9 forming an armour layer that surrounds the insulation system 5. The armour layer also surrounds the water barrier 7, if present. The armour elements 9 comprise metal. The armour elements 9 may consist of metal. The metal may for example be steel, such as mild steel or stainless steel. Each armour element 9 is formed by a plurality of individual wires that are stranded. Each individual wire may for example be made of metal. Alternatively, some of the individual wires may be made of metal and other individual wires may be made of a non-metallic material such as a polymeric material. The armour elements 9 are laid helically along the axial direction of the submarine power cable 1. The armour elements 9 have a pitch, for example in the range of 0.5-4 metres, such as 1-3 metres. The armour elements 9 have a lay direction, which may be the left-hand direction or the right-hand direction.

[0053] The submarine power cable 1 may comprise a corrosion protection layer 11. The corrosion protection layer 11 is arranged to cover the armour layer. The corrosion protection layer 11 is arranged radially outside of the armour layer. The corrosion protection layer 11 may comprise bitumen. The bitumen may be applied onto the armour elements 9 to thereby cover the armour elements 9.

[0054] The submarine power cable 1 may comprise an outer layer 13. The outer layer 13 is arranged around the armour layer. The corrosion protection layer 11 is arranged between the outer layer 13 and the armour layer. The outer layer 13 forms the external surface of the submarine power cable 1. The outer layer 13 may for example comprise polymer yarn, such as polypropylene yarn, wound around the armour layer.

[0055] Turning now to FIG. 2 an example of one of the armour elements 9 is shown in more detail. Each armour element 9 may have this structure. The armour element 9 is made of a plurality of individual wires 9a that are stranded. The stranded individual wires 9a form the armour element 9, which is thus an armour wire made of stranded individual wires that are smaller in diameter than the cross-sectional dimension of the armour element 9.

[0056] Each individual wire 9a may comprise or consist of metal, such as steel, for example mild steel or stainless steel. According to one example, all the individual wires of the armour element 9 are made of the same metal. According to one example, the individual wires 9a of the armour element 9 may be made of different metal materials. One or more individual wires 9a may for example be made of mild steel and one or more individual wires 9a may for example be made of stainless steel.

[0057] The armour elements 9 may be wire ropes.

[0058] According to one example, each individual wire 9a is made of a plurality of stranded wires that are smaller in cross-sectional size than the individual wire 9a. That is, each individual wire 9a may itself be a stranded wire. Alternatively, each individual wire 9a may be a solid wire. According to one variation, the individual wires making up the armour element 9 may be a combination of solid individual wires and individual wires that are stranded.

[0059] According to one example, the armour element 9 may have one central individual wire, as shown in FIG. 2, and a plurality of individual wires wound around the central individual wire. The central individual wire may extend along the central axis of the armour element 9. There may for example be six or more individual wires wound around the central individual wire. Other variations are also possible. There may for example be less than six individual wires wound around the central individual wire. Further, one variation may not have any central individual wire.

[0060] All the individual wires 9a of an armour element 9 may have the same diameter. Alternatively, the diameter of at least two individual wires 9a of an armour element 9 may be mutually different. A central individual wire may for example have a diameter that differs from the individual wires wound around the central individual wire.

[0061] Each armour element 9 may be covered with bitumen around its entire circumference along its entire length. Each armour element 9 may be dipped into a bitumen bath when the submarine power cable 1 is manufactured.

[0062] FIG. 3 shows a cross-sectional view of a multi-core submarine power cable 1. The submarine power cable 1 comprises three power cores 15, 17 and 19. The first power core 15 is formed at least partly by the first conductor 3, the first insulation system 5, and the optional water barrier 7, which in this case is a first water barrier, described above. The second power core 17 and the third power core 19 may be identical to the first power core 15. Thus, the second power core 17 comprises a second conductor 21, a second insulation system 23 provided around the second conductor and optionally a second water barrier 25 arranged around the second insulation system 23. The third power core 19 comprises a third conductor 27, a third insulation system 29 provided around the third conductor 27 and optionally a third water barrier 31 arranged around the third insulation system 29.

[0063] The first power core 15, the second power core 17 and the third power core 19 form a stranded multi-core. The three power cores 15-19 are hence stranded.

[0064] The submarine power cable 1 comprises an armour layer that surrounds the stranded multi-core. The armour layer forms a common armour layer for all three stranded power cores 15-19. The armour layer comprises the previously described armour elements 9. The armour elements 9 are arranged helically around the stranded multi-core.

[0065] The submarine power cable 1 comprises an outer layer 13 surrounding the armour layer.

[0066] In other variations of the submarine power cable, the submarine power cable may comprise exactly two power cores or more than three power cores.

[0067] The inventive concept has mainly been described above with reference to a few examples. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the inventive concept, as defined by the appended claims.