A lightweight dynamic submarine cable

Abstract

This invention relates to the field of submarine cable technology, and in particular to a lightweight dynamic submarine cable. The high-strength lightweight dynamic cable of this invention includes a fully non-metallic armored dynamic cable and a hybrid metal and non-metal armored dynamic cable. Specifically, the fully non-metallic armored high-strength lightweight dynamic cable comprises multiple copper core electrical units, which are twisted together with irregularly shaped fillers to form a cable. An adhesive tape is wrapped around the outside, followed by the sequential extrusion of an inner sheath. Two layers of non-metallic armor wires are then twisted in opposite directions to form armor. After each layer of armor is wrapped with an adhesive tape, an outer sheath is finally extruded. The hybrid metal and non-metal armored high-strength lightweight dynamic cable also comprises multiple copper core electrical units, which are twisted together with irregularly shaped fillers to form a cable. An adhesive tape is wrapped around the outside, followed by the sequential extrusion of an inner sheath. Two layers of armor wires are then twisted in opposite directions to form armor. Each layer of armor includes both metallic and non-metallic armor wires. After each layer of armor is wrapped with an adhesive tape, an outer sheath is finally extruded.

Description

Technical Field

[0001] This invention relates to the field of submarine cable technology, and in particular to a lightweight dynamic submarine cable. Background Technology

[0002] With the rapid development of offshore floating wind power, offshore oil and gas development, offshore floating platforms and deep-sea marine engineering, dynamic cables, as the core carrier for the transmission of electrical energy and signals between floating bodies and fixed infrastructure, are subjected to complex and harsh working conditions such as alternating loads from wind, waves and currents, vertical displacement of floating bodies, repeated bending and torsion, high salt corrosion of seawater, and high pressure in deep water.

[0003] Currently, most dynamic cables in the industry adopt an all-metal steel wire armor structure, which has many inherent technical defects: the all-metal steel wire armor itself is heavy and the overall cable diameter-to-weight ratio is high, which significantly increases the vertical load on the float and the catenary tension of the cable, making it easy to cause stress concentration and fatigue damage, affecting the overall system safety; metal armor is prone to electrochemical corrosion and rust aging in the high-salt, high-humidity, and seawater immersion environment of the ocean, which limits its service life in deep sea and results in high maintenance and corrosion prevention costs; pure metal armor has high rigidity and generally poor resistance to repeated bending fatigue, making it difficult to adapt to the long-term dynamic reciprocating bending conditions of floating platforms.

[0004] Therefore, in view of the problems of existing all-metal armored dynamic cables being heavy, susceptible to corrosion, poor fatigue resistance, and having a single structural form, there is an urgent need to develop a lightweight non-metallic (including metal and non-metal hybrid) armored dynamic cable design and manufacturing method that takes into account weight reduction, tensile strength, bending resistance, and corrosion resistance, and is suitable for various dynamic laying scenarios in the ocean. Summary of the Invention

[0005] Therefore, the technical problem to be solved by this invention is to overcome a series of problems existing in the prior art of metal-armored dynamic cables, such as heavy weight, poor corrosion resistance, and weak fatigue resistance. This invention provides a fully non-metallic armored structure and a hybrid metal-non-metallic armored structure, achieving significant weight reduction in the dynamic cable and reducing the overall cable weight and hydrodynamic load. By replacing or partially replacing metal steel wires with non-metallic armor materials, the amount of metal used is reduced at the source, inhibiting electrochemical corrosion in the marine environment and improving the corrosion resistance, durability, and service life of the dynamic cable. Furthermore, the flexibility of the dynamic cable is improved, ensuring the overall tensile, compressive, torsional, and repeated bending mechanical properties of the dynamic cable while reducing weight.

[0006] To solve the above-mentioned technical problems, the present invention provides a lightweight dynamic submarine cable, comprising: Cable core; Inner sheath layer, the inner sheath layer covering the cable core; An armor composite layer is provided, which covers the inner sheath layer. The armor composite layer is formed by combining an even number of armor layers. Each armor layer is provided with an adhesive cloth tape layer. The armor layer is formed by wrapping non-metallic armor wire. An outer sheath layer, which covers the armor composite layer.

[0007] This invention provides a high-strength, lightweight dynamic cable, including a fully non-metallic armored dynamic cable and a hybrid metal and non-metal armored dynamic cable. The fully non-metallic armored high-strength, lightweight dynamic cable comprises multiple copper core electrical units, which are twisted together with irregularly shaped fillers to form a cable. An adhesive tape is wrapped around the outside, followed by the sequential extrusion of an inner sheath. Two layers of non-metallic armor wires are then twisted in opposite directions to form armor. Each layer of armor is followed by an adhesive tape wrapping, and finally, an outer sheath is extruded. The hybrid metal and non-metal armored high-strength, lightweight dynamic cable comprises three copper core electrical units, which are twisted together with irregularly shaped fillers to form a cable. An adhesive tape is wrapped around the outside, followed by the sequential extrusion of an inner sheath. Two layers of armor wires are then twisted in opposite directions to form armor. Each layer of armor includes both metal and non-metal armor wires. Each layer of armor is followed by an adhesive tape wrapping, and finally, an outer sheath is extruded.

[0008] In one embodiment of the present invention, the cable core is composed of a single copper core electrical unit or is obtained by twisting together multiple copper core electrical units; the copper core electrical unit includes, from the inside out, a water-blocking copper conductor, a conductor shielding layer, a water-tree resistant insulation layer, an insulating shielding layer, a metal shielding layer, and a semi-conductive sheath layer.

[0009] Furthermore, when there are two or more copper core electrical units, a filler is provided between adjacent copper core electrical units. The filler can fill the gaps between multiple copper core electrical units, keeping the cable core cross-section round, fixing the position of the core, and preventing its displacement and friction damage. At the same time, it buffers external forces such as deep-sea compression and bending, improves the overall structural stability and compressive strength, adapts to the complex dynamic working conditions of submarine cables, and also facilitates the subsequent processing and forming of sheath and armor layers.

[0010] Furthermore, the number of copper core electrical units is 1-24. Setting 1-24 copper core electrical units can flexibly adapt to different transmission capacities and engineering requirements.

[0011] Furthermore, both the non-metallic armored yarn and the metallic armored yarn are extruded with a polyethylene (PE) sheath layer. The polyethylene sheath of a certain thickness is extruded onto the outside of the non-metallic armored yarn to meet tensile strength requirements while preventing mutual wear between adjacent structures. Different dimensions are designed according to different project requirements.

[0012] In one embodiment of the present invention, the armor layer further includes metal armor wires, and the armor layer is formed by alternating arrangements of a non-metallic armor wire and a metal armor wire.

[0013] In one embodiment of the present invention, the armor layer further includes metal armor wires, and the armor layer is formed by alternating arrangements of two non-metallic armor wires and one metal armor wire. When the water depth is too great and the conductor cross-section is required to be too large, a non-metallic armored dynamic cable can be selected. For low-tensile, high-salt, and highly corrosive sea areas, all-non-metallic armor is selected; for high-tensile, heavy-load conditions, a metal-non-metal hybrid armor is selected.

[0014] In one embodiment of the present invention, the non-metallic armoring filament is aramid, carbon fiber or glass fiber, and the metallic armoring filament is galvanized steel wire.

[0015] In one embodiment of the present invention, adjacent armor layers are twisted in opposite directions within the armor composite layer. This reverse twisting of the two armor layers can mutually cancel out the torsional stress generated by the twisting, preventing the cable from twisting or buckling on its own. Simultaneously, it improves the overall structural tightness and tensile and torsional resistance, balances stress, reduces damage from dynamic bending and wave impact, and is suitable for the long-term reciprocating motion of submarine cables.

[0016] In one embodiment of the present invention, both the inner sheath layer and the outer sheath layer are made of polyethylene.

[0017] This invention also provides a method for preparing a lightweight dynamic submarine cable, comprising the following steps: S11: Copper core electrical units are twisted together to form the cable core; S12: Extrusion is performed on the outer surface of the cable core to obtain an inner sheath layer; S13: Non-metallic armor wire is wrapped around the surface of the inner sheath layer to form a first armor layer. At least one layer of coated cloth tape and armor layer are wrapped around the outside of the first armor layer at intervals to form an armor composite layer. The armor layers of adjacent layers are twisted in opposite directions. S14: Extrusion is performed on the surface of the armor composite layer to obtain the outer sheath layer.

[0018] In one embodiment of the present invention, the inner sheath layer is prepared by arranging the three copper core electrical units and fillers according to the cross-section and placing them on the distribution plate; after cabling, the cloth tape is wrapped around it and the inner sheath layer is extruded.

[0019] In one embodiment of the present invention, the method for preparing the copper core electrical unit is as follows: S21: Copper wires are twisted together and then squeezed to obtain a water-blocking copper conductor; S22: A conductor shielding layer, a water-tree resistant insulating layer, and an insulating shielding layer are sequentially extruded onto the surface of the water-blocking copper conductor. S23: Wrap copper wire around the surface of the insulating shielding layer to obtain a metal shielding layer; S24: A semi-conductive sheath layer is obtained by extruding the surface of the metal shielding layer.

[0020] Specifically, water-blocking copper conductors are selected, and multi-layer stranding and re-stranding processes are adopted; the single wires and strands are twisted into a round shape without skipped wires or loose strands, and the stranding gaps are filled with sealant evenly; the conductor shielding layer, insulation layer, and insulation shielding layer are formed by three-layer co-extrusion molding, and the insulation concentricity, sulfidation degree, and mechanical and physical properties all meet the requirements of the submarine cable standard (TICW 29-2024). Then, the metal shielding layer and the semi-conductive polyethylene sheath are produced in sequence.

[0021] Compared with the prior art, the above-described technical solution of the present invention has the following advantages: 1. The invention has outstanding lightweight effect: Compared with traditional all-metal armor, all-non-metal armor has a large weight reduction, and hybrid armor can achieve moderate weight reduction, effectively reducing the bearing pressure of the float and the force of the underwater ocean current, and improving the stress state of the cable catenary. 2. The corrosion resistance of this invention is greatly improved: the all-non-metallic structure eliminates the risk of metal corrosion, and the hybrid armor relies on the outer non-metallic layer to isolate seawater, avoiding electrochemical corrosion of the inner metal layer, making it suitable for the high-salt corrosion environment of the ocean and extending its service life. 3. The present invention has good dynamic fatigue resistance: the non-metallic armor has excellent flexibility and can withstand long-term reciprocating bending and torsional alternating loads of floating platforms, reducing the risk of fatigue fracture. 4. This invention has a wide range of working conditions adaptability: it has a variety of armor configurations, including all-non-metallic and mixed metal and non-metallic, which can cover dynamic cable applications with different load levels in shallow sea, mid-sea and deep sea, and has strong versatility. 5. The invention has excellent overall economic benefits: By adopting a fully non-metallic armored structure and a metal-non-metallic hybrid armored structure, the invention significantly reduces the overall weight of the dynamic cable. With the significant reduction in cable weight, the number of buoyancy blocks required for the laying of the dynamic cable is greatly reduced, directly reducing the cost of buoyancy block material procurement, prefabrication, and offshore hoisting and laying. The costs of subsequent operation, maintenance, corrosion prevention, inspection and replacement are also significantly reduced. Attached Figure Description

[0022] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0023] Figure 1 This is a cross-sectional view of the high-strength, lightweight dynamic cable with all-non-metallic armor, as shown in Example 1. Figure 2 This is a cross-sectional view of the high-strength, lightweight dynamic cable with a hybrid metal and non-metal armor, as described in Example 3. Figure 3 A 3D view of the wire splitting and take-up modules of the armor-mounting machine; Figure 4 Front view of the large distribution board of the armoring machine's distribution module; Figure 5 Front view of the small distribution board of the armoring machine distribution module; Figure 6 This is a cross-sectional view of a copper-core electrical unit.

[0024] Explanation of reference numerals in the attached diagram: 1-Copper core electrical unit, 2-Filling material, 3-Inner sheath layer, 4-Coated cloth tape layer, 5-Outer sheath layer, 6-Non-metallic armor wire, 7-Metallic armor wire, 8-Armoring machine take-up mold, 9-Small branch board of armoring machine, 10-Large branch board of armoring machine, 11-Armor wire through hole of large branch board, 12-Dynamic cable through hole of large branch board, 13-Outer layer through hole of armor wire of small branch board, 14-Inner layer through hole of armor wire of small branch board, 15-Dynamic cable through hole of small branch board, 101-Water-blocking copper conductor, 102-Conductor shielding layer, 103-Water-tree resistant insulation layer, 104-Insulating shielding layer, 105-Metallic shielding layer, 106-Semi-conductive sheath layer. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0026] Example 1: Lightweight Dynamic Submarine Cable with Pure Carbon Fiber Armor Reference Figure 1 As shown, the lightweight dynamic submarine cable of the present invention includes: The cable core; an inner sheath layer 3, which covers the cable core; an armor composite layer, which covers the inner sheath layer 3; and an outer sheath layer 5, which covers the armor composite layer.

[0027] The cable core is formed by twisting together three copper core electrical units 1, with filler material 2 between each pair of copper core electrical units; the copper core electrical unit 1 includes, from the inside out, a water-blocking copper conductor 101, a conductor shielding layer 102, a water-tree resistant insulation layer 103, an insulation shielding layer 104, a metal shielding layer 105, and a semi-conductive sheath layer 106.

[0028] The outer diameter of the water-blocking copper conductor 101 is 41.3 mm, the thickness of the conductor shielding layer 102 is 1.1 mm, the thickness of the water-tree resistant insulation layer 103 is 8.5 mm, the thickness of the insulating shielding layer 104 is 1 mm, the outer diameter of the copper wire in the metal shielding layer 105 is 0.8 mm, the thickness of the semi-conductive sheath layer 106 is 2.5 mm, the thickness of the inner sheath layer 3 is 4.5 mm, the thickness of the adhesive-coated cloth tape layer 4 is 0.3 mm, and the thickness of the outer sheath layer 5 is 6.5 mm.

[0029] The armor composite layer is obtained by twisting two armor layers in opposite directions. Each armor layer is provided with an adhesive cloth tape layer 4 between the armor layers. Each armor layer is obtained by wrapping non-metallic armor wires 6 around the surface of the upper layer.

[0030] The non-metallic armoring yarn 6 is composed of 4 mm thick carbon fiber filaments and a 1 mm thick polyethylene sheath. The density of the carbon fiber armoring yarn is 1.378 g / cm³. 3 The tensile strength of a single strand is 8.9 kN (60.6% higher than that of 6 mm pure steel wire).

[0031] The preparation method in this embodiment is as follows: (1) Production of three-core 1200 mm 2 The cross-section of the copper core electrical unit 1; the dynamic cable electrical unit adopts a wet structure, namely, a water-blocking copper conductor 101, a conductor shielding layer 102, a water-tree resistant insulation layer 103, an insulation shielding layer 104, a metal shielding layer 105, and a semi-conductive sheath layer 106. (2) The water-blocking copper conductor 101 adopts a concentric layered stranded integral compaction structure, with the single wires arranged in layers as 1+6+12+18+24+30. The single wires are made of copper rods with a purity greater than 99%, and the copper rods conform to standard GB / T 3952. After being stranded in reverse layers, they are extruded and formed, with the filling coefficient controlled at 0.9±0.02, and then filled with water-blocking adhesive; (3) The conductor shielding layer 102, the water-tree resistant insulating layer 103, and the insulating shielding layer 104 are simultaneously extruded onto the outer periphery of the water-blocking copper conductor 101 using a three-layer co-extrusion process, and the three-layer structure is tightly bonded at the interface without air gaps. The metal shielding layer 105 is wrapped with 34 copper wires with a diameter of 0.8 mm; (4) Finally, the semiconductive sheath layer 106 is extruded to obtain the copper core electrical unit 1.

[0032] (5) Arrange the copper core electrical unit 1 and the filler 2 according to the cross-section at the corresponding positions on the distribution plate to avoid core misalignment and stress concentration. After cabling, wrap with fabric tape and extrude the inner sheath layer 3; (6) The first layer of non-metallic armor wire 6 (carbon fiber wire) passes through the wire splitting module and wire take-up module of the armoring machine in sequence, and completes the first layer of armoring on the outside of the inner sheath layer 3. After forming, it is wrapped around the coated cloth tape layer 4. The second layer of armor also uses non-metallic armor wire 6 (carbon fiber wire), which is twisted in the opposite direction to the first layer. After the armor is formed, it is wrapped around the coated cloth tape layer 4 again to form an armor composite layer.

[0033] The wire splitting module and wire take-up module include an armoring machine take-up mold 8, an armoring machine small wire splitting plate 9, and an armoring machine large wire splitting plate 10. During operation, the armoring wires pass sequentially through the armoring machine large wire splitting plate 10, the armoring machine small wire splitting plate 9, and the armoring machine take-up mold 8 to complete one layer of armoring forming.

[0034] The armoring machine's large splitter board 10 includes a large splitter board armor wire guide hole 11 and a large splitter board dynamic cable guide hole 12. To prevent the large splitter board armor wire guide hole 11 from causing wear to the non-metallic armor wire 6, a polyethylene pad is added to the large splitter board armor wire guide hole 11.

[0035] The armoring machine's small branch board 9 includes outer layer wire guide holes 13, inner layer wire guide holes 14, and dynamic cable wire guide holes 15. The outer layer wire guide holes 13 and the inner layer wire guide holes 14 have built-in PE pads. The armoring machine's small branch board 9 is used when performing mixed metal and non-metal armoring; it is removable at other times.

[0036] The tension of the yarn is controlled throughout the production process to ensure uniform tension, tight wrapping without gaps, and a round and even finished armor layer with no loose strands or curling edges.

[0037] (7) A polyethylene outer sheath 5 is extruded onto the surface of the armored composite layer to form a pure carbon fiber armored lightweight dynamic submarine cable.

[0038] Example 2: Lightweight Dynamic Submarine Cable with Pure Aramid Armor The scheme in this embodiment is the same as that in embodiment 1, except that aramid is used instead of carbon fiber.

[0039] The density of aramid armor yarn is 1.278 g / cm³. 3 The tensile strength of a single strand is 34 kN (513.7% higher than that of 6 mm pure steel wire).

[0040] Example 3: Lightweight Dynamic Submarine Cable with Carbon Fiber Hybrid Armor like Figure 2 As shown, the scheme in this embodiment is the same as that in embodiment 1, except that: a 1:1 ratio of carbon fiber and galvanized steel wire is used to alternately mix armor to replace pure carbon fiber.

[0041] Example 4: Aramid-blended armored lightweight dynamic submarine cable The scheme in this embodiment is the same as that in embodiment 2, except that: aramid and galvanized steel wire are mixed alternately in a 1:1 ratio to replace pure aramid in the armor.

[0042] Comparative Example 1: The scheme of this comparative example is the same as that of Example 1, except that galvanized steel wire is used instead of carbon fiber.

[0043] Effect evaluation: Mechanical parameters such as tensile strength, stiffness, and minimum bending radius were calculated for both non-metallic armored and hybrid armored dynamic cables. Then, the ultimate bearing capacity and fatigue life of the dynamic cables were checked based on the operating water depth, wind, wave and current loads, and floating body displacement parameters.

[0044] Dynamic cable load verification: Under the same deep-water conditions, the main performance of four lightweight dynamic cables was compared with that of pure galvanized steel wire armored cables based on simulation calculations, as follows: Table 1 Test data for each embodiment and comparative example

[0045] Compared to pure metal armored dynamic cables, non-metal armored dynamic cables have significantly reduced weight, significantly smaller minimum bending radius, and significantly reduced dynamic tension under the same environmental conditions. This indicates that the high-strength lightweight dynamic cable of this invention has outstanding lightweight effect, greater flexibility, less impact from ocean currents, and requires fewer buoyancy modules.

[0046] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A lightweight dynamic submarine cable, characterized in that, include: Cable core; Inner sheath layer (3), the inner sheath layer (3) covers the cable core; The armor composite layer is wrapped around the inner sheath layer (3). The armor composite layer is formed by combining an even number of armor layers. Each armor layer is provided with a coated cloth tape layer (4). The armor layer is formed by wrapping non-metallic armor wire (6). Outer sheath layer (5), which covers the armor composite layer.

2. The lightweight dynamic submarine cable according to claim 1, characterized in that: The cable core is a single copper core electrical unit (1) or is formed by twisting together multiple copper core electrical units (1); the copper core electrical unit (1) includes, from the inside out, a water-blocking copper conductor (101), a conductor shielding layer (102), a water-tree resistant insulation layer (103), an insulation shielding layer (104), a metal shielding layer (105), and a semi-conductive sheath layer (106).

3. The lightweight dynamic submarine cable according to claim 2, characterized in that: When there are two or more copper core electrical units (1), a filler (2) is provided between adjacent copper core electrical units (1).

4. The lightweight dynamic submarine cable according to claim 2, characterized in that: The number of copper core electrical units (1) is 1-24.

5. The lightweight dynamic submarine cable according to claim 1, characterized in that: The non-metallic armor yarn (6) is aramid, carbon fiber or glass fiber.

6. The lightweight dynamic submarine cable according to claim 1, characterized in that: The armor layer also includes metal armor wire (7), and the armor layer is formed by alternating non-metallic armor wire (6) and metal armor wire (7).

7. The lightweight dynamic submarine cable according to claim 1, characterized in that: The armor layer also includes metal armor wire (7), and the armor layer is formed by alternating arrangement of two non-metallic armor wires (6) and one metal armor wire (7).

8. The lightweight dynamic submarine cable according to claim 1, characterized in that: In the armor composite layer, adjacent armor layers are twisted in opposite directions.

9. A method for manufacturing a lightweight dynamic submarine cable, characterized in that, Includes the following steps: S11: Copper core electrical units (1) are stranded together to form a cable core; S12: Extrusion is performed on the outer surface of the cable core to obtain the inner sheath layer (3). S13: Non-metallic armor wire (6) is wrapped around the surface of the inner sheath layer (3) to form the first armor layer. At least one layer of coated cloth tape (4) and armor layer are wrapped around the outside of the first armor layer at intervals to form an armor composite layer. The armor layers of adjacent layers are twisted in opposite directions. S14: Extrusion is performed on the surface of the armor composite layer to obtain the outer sheath layer (5).

10. The preparation method according to claim 9, characterized in that: The method for preparing the copper core electrical unit (1) is as follows: S21: Twist copper wires together and then compress them to obtain a water-blocking copper conductor (101). S22: A conductor shielding layer (102), a water-tree resistant insulating layer (103), and an insulating shielding layer (104) are sequentially extruded onto the surface of the water-blocking copper conductor (101). S23: Copper wire is wrapped around the surface of the insulating shielding layer (104) to obtain a metal shielding layer (105). S24: A semiconductive sheath layer (106) is obtained by extruding on the surface of the metal shielding layer (105).

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