Multi-core submarine cable and manufacturing device therefor

Abstract

The present application provides a multi-core submarine cable and a manufacturing device thereof, where the multi-core submarine cable includes: a power cable including an electrical unit for electric conduction and an optical unit for communication; a buffer and thermal insulation structural unit including a braided rope and a first protective sheath extruded on an outer side of the braided rope; and an auxiliary metal unit including a metal tube and a second protective sheath extruded on an outer side of the metal tube; where cross-sections of the power cable and the buffer and thermal insulation structural unit are both circular, and a cross-sectional diameter of the power cable is equal to a cross-sectional diameter of the buffer and thermal insulation structural unit. The buffer and thermal insulation structural unit, the auxiliary metal unit and at least two power cables are stranded together to form a cable core of the multi-core submarine cable. The present application is capable of improving the stability and reliability of the submarine cable and reduces the production cost of the submarine cable.

Description

[0001] This application claims priority to Chinese patent application No. 202310943277.7, filed with the China National Intellectual Property Administration on July 28, 2023, entitled "Multi-Core Submarine Cable and Manufacturing Device thereof", which is hereby incorporated by reference in its entirety.TECHNICAL FIELD

[0002] The present application relates to the technical field of submarine cables, and more particularly to a multi-core submarine cable and a manufacturing device thereof.BACKGROUND

[0003] With the continuous increase in oil and gas exploitation in continental shelf waters, marine engineering has become an important means for addressing the current energy crisis. During the extraction process of offshore oil and gas, electricity serves as the main power source for offshore oil and gas platforms. Since sufficient electricity cannot be easily generated near offshore platforms, most of the offshore platforms need to rely on power transmission from land-based power grids. Due to those methods such as overhead lines are difficult to implement for offshore power transmission, lightweight and efficient submarine cables have become the most effective solution for achieving safe long-distance power transmission.

[0004] In related technologies, submarine cables contain only a single three-core power cable, which centrally supplies power to all equipment on the platform. This method of transmission is relatively single and has limited transmission capacity, resulting in the need for additional submarine cables to transport oil and gas, thereby increasing the manufacturing cost of the submarine cables. Additionally, when submarine cables exhibit dynamic characteristics during operation, temperature of the system is increased, which may cause changes in the electrical performance parameters of the submarine cables, leading to insufficient stability and reliability of the submarine cables.SUMMARY

[0005] In view of the above, the present application provides a multi-core submarine cable and a manufacturing device thereof, which can improve the stability and reliability of submarine cables and reduce the production cost of the submarine cables.

[0006] A first aspect of the present application provides a multi-core submarine cable, including: a power cable, including an electrical unit for electrical conduction and an optical unit for communication; a buffer and thermal insulation structural unit, including a braided rope and a first protective sheath, the first protective sheath being extruded on an outer side of the braided rope; and an auxiliary metal unit, including a metal tube and a second protective sheath, the second protective sheath being extruded on an outer side of the metal tube; where cross-sections of the power cable and the buffer and thermal insulation structural unit are both circular, and a cross-sectional diameter of the power cable is equal to a cross-sectional diameter of the buffer and thermal insulation structural unit. The buffer and thermal insulation structural unit, the auxiliary metal unit, and at least two power cables are stranded together to form a cable core of the multi-core submarine cable.

[0007] By providing the buffer and thermal insulation structural unit, it is possible to provide buffering and isolation during the stranding process of multiple power cables, effectively preventing the power cables from being subjected to compressive forces during the stranding process, and the buffer and thermal insulation structural unit can also reduce electric power loss during operation of the multi-core submarine cable and control the operating temperature of the multi-core submarine cable, thereby improving the stability and reliability during operation of the multi-core submarine cable; by setting the cross-sectional diameter of the power cable equal to the cross-sectional diameter of the buffer and thermal insulation structural unit, it is possible to ensure that the compounded cable is rounded, thereby improving the roundness of the finished submarine cable; by providing the auxiliary metal unit, which includes a metal tube, it is possible to supply oil or gas for the offshore platform equipment by the metal tube, provide electric power and hydraulic pressure for the underwater equipment, maintain signal transmission, and inject required reagents, ensuring the normal operation of the subsea control system, eliminating the need for an additional submarine cable, and thus reducing the production cost of the multi-core submarine cable. In addition, since the multi-core submarine cable includes at least two power cables, the electric power transmission capacity of the multi-core submarine cable can be improved.

[0008] In some possible implementations, the electrical unit includes a conductor, and further a conductor shield layer, a water-tree-resistant XLPE insulation layer, an insulation shield layer, a first semiconductive water-blocking tape layer, a copper tape shield layer, a second semiconductive water-blocking tape layer, and a third protective sheath, which are sequentially wrapped around an outer side of the conductor from inside to outside.

[0009] In some possible implementations, the conductor includes a plurality of round metal wires and a semiconductive water-blocking adhesive, where the plurality of round metal wires is compacted and stranded together, and the semiconductive water-blocking adhesive fills the compacted and stranded metal wires to form the conductor.

[0010] In some possible implementations, the optical unit includes an optical fiber unit, and an outer sheath tube, a semiconductive inner sheath, an optical unit armor layer, a water-blocking tape layer, and a semiconductive outer sheath, which are sequentially wrapped around an outer side of the optical fiber unit from inside to outside.

[0011] In some possible implementations, there are four power cables, three buffer and thermal insulation structural units, and two auxiliary metal units. Among them, centerlines of three of the four power cables form an equilateral triangle, and the other power cable is located at a center of the equilateral triangle; the three buffer and thermal insulation structural units are respectively located on three sides of the equilateral triangle.

[0012] In some possible implementations, the multi-core submarine cable further includes a circular filling unit; four power cables, two buffer and thermal insulation structural units, and two auxiliary metal units are stranded together, and the circular filling unit fills a gap formed after stranding the four power cables, the two buffer and thermal insulation structural units, and the two auxiliary metal units, to form a cable core of the multi-core submarine cable.

[0013] In some possible implementations, the power cable includes three electrical units and one optical unit; among them, the centerlines of the three electrical units form an equilateral triangle, and the optical unit is located in a gap between two adjacent electrical units.

[0014] In some possible implementations, the multi-core submarine cable further includes: a cable inner sheath wrapped around an outer side of the cable core, an armor layer wrapped around an outer side of the cable inner sheath, an anti-corrosion layer coated on an outer side of the armor layer, and a cable outer sheath wrapped around an outer side of the anti-corrosion layer.

[0015] A second aspect of the present application provides a manufacturing device for a multi-core submarine cable, including: a power unit turntable, a structural unit wire spool, an auxiliary metal unit wire spool, a structural unit tension control device, a wire positioning and shaping device and a stranding device, where the power unit turntable is used to payout a power cable, the structural unit wire spool is used to payout a buffer and thermal insulation structural unit, the auxiliary metal unit wire spool is used to payout an auxiliary metal unit; the structural unit tension control device is used to control a tension of the structural unit wire spool during a payout process, so that the tension during the payout process of the structural unit wire spool is the same as a tension during a payout process of the power unit turntable; the wire positioning and shaping device is used to determine positions of the power cable, the buffer and thermal insulation structural unit and the auxiliary metal unit according to a cable core structure of the multi-core submarine cable; the stranding device is used to strand the power cable, the buffer and thermal insulation structural unit and the auxiliary metal unit after wire separation and shaping, to form the cable core of the aforementioned multi-core submarine cable.

[0016] In some possible implementations, the structural unit tension control device includes a tension control telescopic unit, a rotary support wheel, a tension control chain and a structural unit wire guiding device; the structural unit wire guiding device includes two sets of parallel guide wheels, and the buffer and thermal insulation structural unit passes through a middle position between the two guide wheels; the tension control telescopic unit is connected with the tension control chain, and realizes reciprocating extension and retraction movements through the rotary support wheel, so as to adjust the payout tension of the structural unit wire spool.

[0017] Understandably, the manufacturing device for a multi-core submarine cable according to the second aspect described above corresponds to the structure of the first aspect mentioned above, and therefore, the beneficial effects it can achieve may refer to those corresponding to structure described above, and will not be repeated here.

[0018] Combined with the above technical solutions, the present application provides a multi-core submarine cable and a manufacturing device thereof, where by providing the buffer and thermal insulation structural unit, it is possible to provide a buffer and isolation during the stranding process of multiple power cables, effectively preventing the power cables from being subjected to compressive forces during the stranding process, and the buffer and thermal insulation structural unit can also reduce electric power loss during operation of the multi-core submarine cable and control the operating temperature of the multi-core submarine cable, thereby improving the stability and reliability during operation of the multi-core submarine cable; by setting the cross-sectional diameter of the power cable equal to the cross-sectional diameter of the buffer and thermal insulation structural unit, it is possible to ensure that the compounded cable is rounded, thereby improving the roundness of the finished submarine cable; by providing the auxiliary metal unit, which includes a metal tube, it is possible to supply oil or gas for the offshore platform equipment by the metal tube, provide electric power and hydraulic pressure for the underwater equipment, maintain signal transmission, and inject required reagents, ensuring the normal operation of the subsea control system, eliminating the need for an additional submarine cable, and thus reducing the production cost of the multi-core submarine cable. In addition, since the multi-core submarine cable includes at least two power cables, the electric power transmission capacity of the multi-core submarine cable can be improved.BRIEF DESCRIPTION OF DRAWINGS

[0019] FIG. 1 is a cross-sectional view of a multi-core submarine cable according to an embodiment of the present application. FIG. 2 is a cross-sectional view of an electrical unit according to an embodiment of the present application. FIG. 3 is a cross-sectional view of an optical unit according to an embodiment of the present application. FIG. 4 is a cross-sectional view of a buffer and thermal insulation structural unit according to an embodiment of the present application. FIG. 5 is a cross-sectional view of an auxiliary metal unit according to an embodiment of the present application. FIG. 6 is a cross-sectional view of another structure of the multi-core submarine cable according to an embodiment of the present application. FIG. 7 is a schematic structural diagram of a manufacturing device for a multi-core submarine cable according to an embodiment of the present application. FIG. 8 is a schematic structural diagram of a structural unit tension control device according to an embodiment of the present application. FIG. 9 is a top view of a wire positioning and shaping device according to an embodiment of the present application. DESCRIPTION OF EMBODIMENTS

[0020] In order to more clearly understand the above objectives, features, and advantages of the present application, the following provides a detailed description of the present application in conjunction with the drawings and specific embodiments. It should be noted that the embodiments and the features within the embodiments of the present application can be combined without conflict.

[0021] In the following description, numerous specific details are set forth to provide a thorough understanding of the present application. The embodiments described are only some of the embodiments of the present application, not all of them.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terms used in the description of the present application are solely for the purpose of describing specific embodiments and are not intended to limit the present application.

[0023] Further, it should be noted that, in this document, terms such as "include", "contain", or any other variation thereof are intended to encompass non-exclusive inclusion, such that processes, methods, articles, or devices that include a series of elements not only include these elements but also include other elements not explicitly listed, or elements inherent to such processes, methods, articles, or devices. Without further limitation, an element defined following a statement "including an ..." does not exclude the presence of additional identical element(s) in the process, method, article, or device that includes that element.

[0024] In the present application, the term "at least one" means one or a plurality, and the term "a plurality" means two or more than two. The term "and / or" describes an associated relationship between objects and indicates that three types of relationships may exist. For example, "A and / or B" may represent: A exists alone, both A and B exist simultaneously, or B exists alone, where A and B may be singular or plural.

[0025] Please refer to FIGS. 1 to 5, where FIG. 1 is a cross-sectional view of a multi-core submarine cable according to the present application; FIG. 2 is a cross-sectional view of an electrical unit according to the present application; FIG. 3 is a cross-sectional view of an optical unit according to the present application; FIG. 4 is a cross-sectional view of a buffer and thermal insulation structural unit according to the present application; and FIG. 5 is a cross-sectional view of an auxiliary metal unit according to the present application.

[0026] A multi-core submarine cable includes: a power cable 1, including an electrical unit 101 for electric conduction and an optical unit 102 for communication; a buffer and thermal insulation structural unit 2, including a braided rope 22 and a first protective sheath 23 extruded on an outer side of the braided rope 22; an auxiliary metal unit 4, including a metal tube 24 and a second protective sheath 25 extruded on an outer side of the metal tube 24; where cross-sections of the power cable 1 and the buffer and thermal insulation structural unit 2 are both circular, and a cross-sectional diameter of the power cable 1 is equal to a cross-sectional diameter of the buffer and thermal insulation structural unit 2, and the buffer and thermal insulation structural unit 2, the auxiliary metal unit 4, and at least two power cables 1 are stranded together to form a cable core of the multi-core submarine cable.

[0027] By providing the buffer and thermal insulation structural unit 2, it is possible to provide buffering and isolation during the stranding process of multiple power cables 1, effectively preventing the power cables 1 from being subjected to compressive forces during the stranding process, and the buffer and thermal insulation structural unit 2 can also reduce electric power loss during operation of the multi-core submarine cable and control the operating temperature of the multi-core submarine cable, thereby improving the stability and reliability during operation of the multi-core submarine cable; by setting the cross-sectional diameter of the power cable 1 equal to the cross-sectional diameter of the buffer and thermal insulation structural unit 2, it is possible to ensure that the compounded cable is rounded, thereby improving the roundness of the finished submarine cable; by providing the auxiliary metal unit 4, which includes a metal tube 24, it is possible to supply oil or gas for the offshore platform equipment by the metal tube 24, provide electric power and hydraulic pressure for the underwater equipment, maintain signal transmission, and inject required reagents, ensuring the normal operation of the subsea control system, eliminating the need for an additional submarine cable, and thus reducing the production cost of the multi-core submarine cable. In addition, since the multi-core submarine cable includes at least two power cables 1, the electric power transmission capacity of the multi-core submarine cable can be improved.

[0028] In some embodiments, a material of the braided rope 22 is polypropylene. The braided rope 22 made of this material enables the buffer and thermal insulation structural unit 2 to have a high strength, thereby ensuring structural stability during the stranding process of the multi-core submarine cable. In addition, a material of the first protective sheath 23 may be polyethylene. This embodiment does not specifically limit the material of the first protective sheath 23.

[0029] In some embodiments, the cross-sectional diameter of the braided rope 22 is equal to 2 / 3 of the cross-sectional diameter of the power cable 1. The braided rope 22 is formed by braiding multiple strands of high-strength PP monofilament in a stranded form. A polyethylene protective sheath 23 is extrusion-coated on an outer layer of the braided rope 22. Among them, an extrusion temperature of the polypropylene (PP) material is controlled at 200 °C, and an extrusion temperature of the polyethylene is between 160 °C and 170 °C, ensuring production stability of the first protective sheath 23 with polyethylene material during the extrusion process. Finally, the cross-sectional diameter of the power cable 1 is equal to the cross-sectional diameter of the buffer and thermal insulation structural unit 2.

[0030] In some embodiments, the metal tube 24 is a stainless-steel tube, and a material of the second protective sheath 25 is polyethylene. The auxiliary metal unit 4 plays an auxiliary role in filling oil or gas for offshore platform equipment, and also provides electric power and hydraulic pressure for submarine equipment, maintains signal transmission, and injects required reagents, thereby ensuring the normal operation of the subsea control system.

[0031] Please refer again to FIG. 2, the electrical unit 101 includes a conductor 8, and further a conductor shield layer 9, a water-tree-resistant XLPE insulation layer 10, an insulation shield layer 11, a first semiconductive water-blocking tape layer 12, a copper tape shield layer 13, a second semiconductive water-blocking tape layer 14 and a third protective sheath 15, which are sequentially wrapped around an outer side of the conductor 8 from inside to outside.

[0032] In some implementations, the conductor 8 includes multiple round metal wires and a semiconductive water-blocking adhesive; the multiple round metal wires are compacted and stranded together, and the semiconductive water-blocking adhesive fills the compacted and stranded metal wires to form the conductor.

[0033] Specifically, the conductor 8 is an extruded conductor structure, formed by compacting and stranding multiple round metal wires in multiple layers. During the stranding process, the semiconductive water-blocking adhesive is filled into the gaps between the individual strands. The semiconductive water-blocking adhesive is a water-blocking material composed of a semiconductive compound, and may be used to replace a semiconductive water-blocking tape in conventional submarine cable structures, thereby achieving better longitudinal water-blocking effect.

[0034] The conductor shield layer 9, the water-tree-resistant XLPE insulation layer 10, and the insulation shield layer 11 form a cross-linked three-layer co-extruded structure, which carries an operating voltage of the submarine cable. The insulation material is water-tree-resistant XLPE material, which may ensure that no water tree is formed when water enters the submarine cable, allowing insulation extrusion and ensuring the stability of the electric circuit. The cross-linked three-layer co-extruded structure undergoes cable core degassing, which removes low-molecular gases generated during the cross-linking reaction of the submarine cable, avoiding adverse effects on the performance of the submarine cable.

[0035] The first semiconductive water-blocking tape layer 12, the copper tape shield layer 13, and the second semiconductive water-blocking tape layer 14 are used for synchronous wrapping. The first semiconductive water-blocking tape layer 12 and the second semiconductive water-blocking tape layer 14 further provide buffering and water-blocking effects, and the copper tape shield layer 13 is formed by a soft copper tape for wrapping in an overlapping manner, to provide an enhanced electromagnetic shielding effect.

[0036] In some embodiments, a material of the third protective sheath 15 is polyethylene, thereby providing an improved waterproof effect for the electrical unit 101. Please refer again to FIG. 3, the optical unit 102 includes an optical fiber unit 16, and further an outer sheath tube 17, a semiconductive inner sheath 18, an optical unit armor layer 19, a water-blocking tape layer 20 and a semiconductive outer sheath 21, which are sequentially wrapped around an outer side of the optical fiber unit 16 from inside to outside.

[0037] Please refer again to FIG. 1, the power cable 1 includes three electrical units 101 and one optical unit 102. Among them, centerlines of the three electrical units 101 form an equilateral triangle, and the optical unit 102 is located in the gap between adjacent two electrical units 101.

[0038] Specifically, after extrusion of the phase-separated sheath of the power cable 1 is completed, according to the arrangement positions of the three-phase sheathed cable cores, the three-core (i.e., three electrical units 101) stranding of the power cable 1 is performed. The optical unit 102 is filled into the gap between adjacent two electrical units 101 and a cylindrical polyethylene strip is filled into a void, thereby achieving better roundness effect during cable formation. A synthetic tape is then wrapped around the outer layer of the core, to round the stranded three-core.

[0039] In some embodiments, the multi-core submarine cable further includes: a cable inner sheath 5 wrapped around the outer side of the cable core, an armor layer 6 wrapped around an outer side of the cable inner sheath 5, an anti-corrosion layer coated on an outer side of the armor layer 6, and a cable outer sheath 7 wrapped around an outer side of the anti-corrosion layer.

[0040] It should be noted that during the transmission process of the electrical unit 101, there is electric field interaction and heat phenomenon. When the multi-core submarine cable is in operation, the current distribution in the cable core is uneven, and an eddy current is generated in both the copper tape shield layer 13 and the armor layer 6, thereby generating electrical energy losses. At the same time, during the operation of the multi-core submarine cable, the temperature gradually increases from the cable core, the copper tape shield layer 13, the third protective sheath 15, the cable inner sheath 5, and up to the armor layer 6. After a period of time, the temperature reaches equilibrium. The rise in temperature affects the performance parameters of the cable in use. By using the buffer and thermal insulation structural unit 2 in a gapped stranding process, the electric power loss during operation of the multi-core submarine cable can be significantly reduced, and the operating temperature of the multi-core submarine cable can be effectively controlled, thereby improving the stability of the multi-core submarine cable during operation.

[0041] Please refer again to FIG. 1, there are four power cables 1, three buffer and thermal insulation structural units 2, and two auxiliary metal units 4. Among them, the centerlines of three of the four power cables 1 form an equilateral triangle, and the other power cable 1 is located at the center of the equilateral triangle; and the three buffer and thermal insulation structural units 2 are located on three sides of the equilateral triangle, respectively.

[0042] The multi-core submarine cable further includes a circular filling unit 3; the four power cables 1, three buffer and thermal insulation structural units 2, and two auxiliary metal units 4 are stranded together, and the circular filling unit 3 fills the gaps formed after stranding the four power cables 1, the three buffer and thermal insulation structural units 2 and the two auxiliary metal units 4, to form a cable core of the multi-core submarine cable.

[0043] Specifically, the power cables 1, the buffer and thermal insulation structural units 2, and the auxiliary metal units 4 are stranded together according to the arranged positions of the gaps. The gaps are filled with circular filling units 3 to achieve composite filling during the cabling process, ensuring roundness of the cable core of the multi-core submarine cable.

[0044] In some embodiments, the circular filling unit 3 is a polyethylene circular filling rod.

[0045] In some embodiments, the number of the power cable 1 is not specifically limited and can be provided according to actual requirements. The number of the buffer and thermal insulation structural unit 2 is adjusted accordingly based on the number of the power cable 1. For example, when there are five power cables 1, there are two buffer and thermal insulation structural units 2.

[0046] Please refer to FIG. 6, which is a cross-sectional view of another structure of the multi-core submarine cable according to an embodiment of the present application. There are seven power cables 1, and the power cable 1 is only provided with the electrical unit 101, in order to enhance the load capacity of the power cable 1. The optical unit 102 and the auxiliary metal unit 4 are provided in the gaps between adjacent power cables 1.

[0047] For better understanding, the following provides a detailed description of the multi-core submarine cable according to the embodiments of the present application.

[0048] Four power cables 1 and three buffer and thermal insulation structural units 2 are stranded together to form a cable. Two auxiliary metal units 4 are filled into the gaps between the power cables 1 and the buffer and thermal insulation structural units 2. The remaining gaps are filled with the circular filling unit 3 (such as flexible circular PE strip and PP filling rope), to ensure improved bending flexibility of the multi-core submarine cable. These filling materials fully occupy the voids in the stranded cable, ensuring the roundness of the formed multi-core submarine cable. After the cable is formed, a braided synthetic tape is wrapped around the outer layer, serving functions such as tightening, buffering, and isolation.

[0049] After the cable is formed, the cable core of the multi-core submarine cable is extrusion-coated with a cable inner sheath 5, to ensure better waterproof effect of the multi-core submarine cable. The armor layer 6 is made of a steel wire, and the type of the steel wire is selected according to a specific water depth requirement for use of the multi-core submarine cable. For example, a conventional galvanized low-carbon steel wire is used for a shallow water depth, a galvanized medium-carbon steel wire is used for a deeper water depth, and a galvanized high-carbon steel wire is used for armoring in a complex usage condition to ensure superior armoring mechanical properties. An anti-corrosion layer is applied on the outer surface of the armor layer 6. The anti-corrosion layer is formed by spraying modified asphalt, ensuring uniform and complete coverage on the surface of the armor layer 6.

[0050] Please refer to FIG. 7, which is a schematic structural diagram of a manufacturing device for the multi-core submarine cable according to an embodiment of the present application.

[0051] The manufacturing device for the multi-core submarine cable includes: a power unit turntable 261, a structural unit wire spool 263, an auxiliary metal unit wire spool 262, a structural unit tension control device 265, a wire positioning and shaping device 266 and a stranding device 267. The power unit turntable 261 is used to payout the power cable 1, the structural unit wire spool 263 is used to payout the buffer and thermal insulation structural unit 2, the auxiliary metal unit wire spool 262 is used to payout the auxiliary metal unit 4; the structural unit tension control device 265 is used to control the tension of the structural unit wire spool 265 during the payout process, so that the tension of the structural unit wire spool 263 during the payout process is the same as the tension of the power unit turntable 261 during the payout process; the wire positioning and shaping device 266 is used to determine the positions of the power cable 1, the buffer and thermal insulation structural unit 2 and the auxiliary metal unit 4 according to the core structure of the multi-core submarine cable; the stranding device 267 is used to strand the power cable 1, the buffer and thermal insulation structural unit 2 and the auxiliary metal unit 4 after wire separation and shaping to form the above cable core of the multi-core submarine cable.

[0052] Specifically, the manufacturing device of the multi-core submarine cable further includes: a filling unit wire spool 264, a cable wrapping device 268, an upper guide wheel 269A, and a lower guide wheel 269B. The filling unit wire spool 264 is used for paying out the circular filling unit 3; the cable wrapping device 268 is used for wrapping a layer of braided synthetic tape around the cable core of the stranded multi-core submarine cable, serving functions such as tightening, buffering and isolation.

[0053] As shown in FIG. 7, the manufacturing device for the multi-core submarine cable further includes: a vertical cable-forming base platform 2610, a vertical cable-forming first platform 2611, a vertical cable-forming second platform 2612, and a vertical cable-forming stranding platform 2613. The power unit turntable 261, the auxiliary metal unit wire spool 262, and the lower guide wheel 269B are located on the vertical cable-forming base platform 2610; the structural unit wire spool 263 and the filling unit wire spool 264 are located on the vertical cable-forming first platform 2611; the structural unit tension control device 265 is located on the vertical cable-forming second platform 2612; and the wire positioning and shaping device 266 is located on the vertical cable-forming stranding platform 2613.

[0054] It should be understood that during the composite stranding process of the multi-core submarine cable, since the multiple power cables 1, the buffer and thermal insulation structural units 2, the auxiliary metal units 4 and the circular filling units 3 are included and these units have different tension characteristics, it is difficult to control the shaping in conventional stranding for cable formation. The internal structure of the buffer and thermal insulation structural unit 2 is a high-strength polypropylene braided rope, with a polyethylene sheath extruded on its outer layer, this makes that the buffer and thermal insulation structural unit 2 has a high strength, but has a low unit weight and a low tension control, thus requiring increased tension control during stranding for cable formation; and the internal structure of the auxiliary metal unit 4 is a stainless-steel tube, which has high strength, thus requiring reduced tension control during stranding for cable formation. Therefore, during the cable-forming stranding process of the units of the multi-core submarine cable, differences in tension control for the units may cause positional offset of the units, leading to difficulties in shaping the composite stranding of the multi-core submarine cable and uneven tension distribution among these units, resulting in a serpentine appearance in the cable.

[0055] According to the manufacturing device for the multi-core submarine cable provided in this embodiment, the power cable 1 is paid off from the power unit turntable 261 located on the vertical cable-forming base platform 2610, the auxiliary metal unit 4 is paid off from the auxiliary metal unit wire spool 262, and the circular filling unit 3 is paid off from the filling unit wire spool 264 located on the vertical cable-forming first platform 2611. Due to the particularity of the buffer and thermal insulation structural unit 2, the buffer and thermal insulation structural unit 2, after being paid off from the vertical cable-forming first platform 2611, passes through the structural unit tension control device 265 on the vertical cable-forming second platform 2612, and is threaded into the wire positioning and shaping device 266 located on the vertical cable-forming stranding platform 2613. Thereafter, the buffer and thermal insulation structural unit 2, together with the power cable 1, the auxiliary metal unit 4 and the circular filling unit 3, are stranded by the stranding device 267 to be formed into a composite cable, which forms a cable core of a complete stranded cable.

[0056] Please refer to FIG. 8, the structural unit tension control device 265 includes a tension control telescopic unit 265A, a rotary support wheel 265B, upper and lower limit support devices 265C1, 265C2, a tension control chain 265D, a slide rail device 265E and a structural unit wire guiding device 265F. The structural unit wire guiding device 265F includes two sets of parallel guide wheels, and the buffer and thermal insulation structural unit 2 passes through a middle position between the two guide wheels; the tension control telescopic unit 265A is connected with the tension control chain 265D, realizing reciprocating extension and retraction movements through the rotary support wheel 265B, to control the tension variation in the payout of the buffer and thermal insulation structural unit 2.

[0057] During the stranding process of the buffer and thermal insulation structural unit 2, as the vertical stranding equipment rotates to enable the various units to be stranded, the tension of the buffer and thermal insulation structural unit 2 varies, pushing the structural unit wire guiding device 265F to adjust and change the tension by the tension control telescopic unit 265A and the tension control chain 265D. When the structural unit wire guiding device 265F is at an upper limit position 265C1, the payout tension of the buffer and thermal insulation structural unit 2 is relatively large, which is fed back to the structural unit tension control device 265, causing the wire guiding device 265F to move downward, thereby reducing the payout tension of the buffer and thermal insulation structural unit 2 so that the buffer and thermal insulation structural unit 2 is properly positioned, to ensure the roundness of the stranded cable core. When the payout tension is relatively small, the structural unit wire guiding device 265F is at a lower limit position, which is fed back to the structural unit tension control device 265, causing the structural unit wire guiding device 253F to move upward, increasing the payout tension of the buffer and thermal insulation structural unit 2, to ensure a stable cable formation process.

[0058] Please refer to FIG. 9, the wire positioning and shaping device 266 is a wire separation disc for stranding. The wire separation disc for stranding includes a power unit limiting hole 266A, a structural unit limiting hole 266B, an auxiliary metal unit limiting hole 266C, and a circular filling unit limiting hole 266D. The power cable 1, the buffer and thermal insulation structural unit 2, the circular filling unit 3, and the auxiliary metal unit 4 are threaded through the wire positioning and shaping device 266 in sequence according to the structure of the multi-core submarine cable, thereby ensuring stability of the stranding process of the units. The wire positioning and shaping device 266 determines the distribution of threading holes based on the specific structural positions of the cable core.

[0059] Compared with the related art, the embodiments of the present application have at least the following advantages: (1) it realizes the simultaneous transmission of electric power, optical unit communication signals, and hydraulic pressure signals for underwater equipment to multiple offshore wellhead platforms, greatly reducing the amount of raw materials required in conventional submarine cable designs, and lowering the production cost of the multi-core submarine cable; (2) it enables structural optimization of offshore wellhead platforms, reducing their size and weight, thereby decreasing the manufacturing cost of the offshore wellhead platforms; (3) it significantly reduces variations in electric performance parameters of the submarine cable caused by increased system temperature during operation, thereby improving the stability and reliability of the submarine cable; (4) by providing the structural unit tension control device 265 and the wire positioning and shaping device 266, the stranding stability of the multi-core submarine cable can be better ensured, and the roundness of the stranded cable core can be ensured.

[0060] The above description is merely specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled familiar with the art can easily think of variations or substitutions within the technical scope disclosed in the present application, and these variations or substitutions should be covered by the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the appended claims.

Claims

1. A multi-core submarine cable, comprising: a power cable, comprising an electrical unit for electric conduction and an optical unit for communication; a buffer and thermal insulation structural unit, comprising a braided rope and a first protective sheath extruded on an outer side of the braided rope; an auxiliary metal unit, comprising a metal tube and a second protective sheath extruded on an outer side of the metal tube; wherein cross-sections of the power cable and the buffer and thermal insulation structural unit are both circular, a cross-sectional diameter of the power cable is equal to a cross-sectional diameter of the buffer and thermal insulation structural unit, and the buffer and thermal insulation structural unit, the auxiliary metal unit, and at least two power cables are stranded together to form a cable core of the multi-core submarine cable.

2. The multi-core submarine cable according to claim 1, wherein the electrical unit comprises a conductor, and further a conductor shield layer, a water-tree-resistant XLPE insulation layer, an insulation shield layer, a first semiconductive water-blocking tape layer, a copper tape shield layer, a second semiconductive water-blocking tape layer, and a third protective sheath, which are sequentially wrapped around an outer side of the conductor from inside to outside.

3. The multi-core submarine cable according to claim 2, wherein the conductor comprises multiple round metal wires and a semiconductive water-blocking adhesive, wherein the multiple round metal wires are compacted and stranded together, and the semiconductive water-blocking adhesive fills the compacted and stranded metal wires to form the conductor.

4. The multi-core submarine cable according to claim 1, wherein the optical unit comprises an optical fiber unit, and further an outer sheath tube, a semiconductive inner sheath, an optical unit armor layer, a water-blocking tape layer and a semiconductive outer sheath, which are sequentially wrapped around an outer side of the optical fiber unit from inside to outside.

5. The multi-core submarine cable according to claim 1, wherein there are four power cables, three buffer and thermal insulation structural units and two auxiliary metal units; wherein centerlines of three of the four power cables form an equilateral triangle, and the other power cable is located at a center of the equilateral triangle; the three buffer and thermal insulation structural units are located on three sides of the equilateral triangle, respectively.

6. The multi-core submarine cable according to claim 5, wherein the multi-core submarine cable further comprises a circular filling unit; and the four power cables, the three buffer and thermal insulation structural units and the two auxiliary metal units are stranded together, and the circular filling unit fills a gap formed after the four power cables, the three buffer and thermal insulation structural units and the two auxiliary metal units are stranded, to form the cable core of the multi-core submarine cable.

7. The multi-core submarine cable according to claim 1, wherein the power cable comprises three electrical units and one optical unit; wherein centerlines of the three electrical units form an equilateral triangle, and the optical unit is located in a gap between adjacent two electrical units.

8. The multi-core submarine cable according to claim 1, wherein the multi-core submarine cable further comprises: a cable inner sheath wrapped around an outer side of the cable core, an armor layer wrapped around an outer side of the cable inner sheath, an anti-corrosion layer coated on an outer side of the armor layer, and a cable outer sheath wrapped around an outer side of the anti-corrosion layer.

9. A manufacturing device for a multi-core submarine cable, comprising: a power unit turntable, a structural unit wire spool, an auxiliary metal unit wire spool, a structural unit tension control device, a wire positioning and shaping device and a stranding device, wherein the power unit turntable is used to payout a power cable, the structural unit wire spool is used to payout a buffer and thermal insulation structural unit, the auxiliary metal unit wire spool is used to payout an auxiliary metal unit; the structural unit tension control device is used to control a tension of the structural unit wire spool during a payout process, so that the tension of the structural unit wire spool during the payout process is the same as a tension of the power unit turntable during a payout process; the wire positioning and shaping device is used to determine positions of the power cable, the buffer and thermal insulation structural unit and the auxiliary metal unit according to a structure of a cable core of the multi-core submarine cable; and the stranding device is used to strand the power cable, the buffer and thermal insulation structural unit and the auxiliary metal unit after wire separation and shaping, to form the cable core of the multi-core submarine cable according to any one of claims 1 to 8.

10. The manufacturing device for a multi-core submarine cable according to claim 9, wherein the structural unit tension control device comprises a tension control telescopic unit, a rotary support wheel, a tension control chain and a structural unit wire guiding device, wherein the structural unit wire guiding device comprises two sets of parallel guide wheels, the buffer and thermal insulation structural unit passes through a middle position between the guide wheels, the tension control telescopic unit is connected with the tension control chain and realizes reciprocating extension and retraction movements through the rotary support wheel so as to adjust a payout tension of the structural unit wire spool.

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