Large-diameter and large-thickness submarine cable and cooling and conveying device

Abstract

The invention relates to the technical field of submarine cables, and provides a large-diameter and large-thickness submarine cable and a cooling and conveying device, and the large-diameter and large-thickness submarine cable comprises a cable core, a cabling wrapping tape layer, a general wrapping inner protection layer, an armor layer and an outer protection layer. The cable core comprises an electric unit and an optical unit, the electric unit is provided with a conductor, the conductor is of a multi-layer structure, and semi-conductive water-blocking glue is arranged between every two adjacent layers of structures; and both the inner sheath and the outer sheath are prepared from medium-density insulating polyethylene through pressurization and extrusion. According to the submarine cable, the medium-density insulating polyethylene is adopted, so that the inner sheath and the outer sheath which are wrapped together keep relatively good structural strength and environmental stress cracking resistance for a long time, and the submarine cable is prevented from entering water or cracking; the inner protection layer and the outer protection layer are wrapped in a pressurized extrusion mode, so that the medium-density insulation polyethylene can fill gaps on the outer side of the cabling belting layer and the outer side of the armored belting layer, and the problem that the submarine cable in the prior art is poor in water resistance and cracking resistance is solved.

Description

[0001] This application is a divisional application. The original application, application number 202311573446.9, was filed on November 22, 2023. The entire contents of the original application are incorporated herein by reference. Technical Field

[0002] This invention relates to the field of submarine cable technology, and in particular to a large-diameter, thick submarine cable and a cooling and conveying device. Background Technology

[0003] Against the backdrop of "dual carbon" (carbon and carbon emissions), power energy development is gradually shifting towards low-carbon transformation. Wind energy, as a renewable energy source, is an important component of this low-carbon transformation. In recent years, the development of near-shore fixed wind power platforms has approached saturation, with approximately 80% of offshore wind energy resources located in waters deeper than 60 meters. Wind energy development is gradually shifting towards deep-sea areas. As a system for capturing offshore wind energy, floating offshore wind power platforms are the inevitable trend for future offshore wind power development.

[0004] Offshore wind power is experiencing rapid growth due to its proximity to energy consumption centers and superior wind resources compared to onshore wind power. However, given the limited resources, strong ecological constraints, high demand from other economic activities, and dispersed site locations in nearshore areas, the development of offshore wind power towards deeper waters is an inevitable trend. Compared to nearshore wind power, deep-sea areas offer advantages such as superior wind resources, enormous development potential, and fewer limiting factors. Statistics show that over 80% of the world's offshore wind energy potential lies in waters deeper than 40 meters. As offshore wind power expands from shallow nearshore to deep-sea areas, foundation types have evolved from gravity-type, multi-legged, high-pile cap, and monopile foundations to jacket foundations and floating foundations. From an economic perspective, floating foundations are commonly used when the water depth exceeds 60 meters.

[0005] Because submarine cables are located in deep water, they are easily subjected to water flow impacts that can induce vortices and generate vortex-induced vibrations. Vortex-induced vibrations can easily lead to fatigue cracking of the sheath, resulting in a decrease in the cable's water-blocking performance and subsequent water ingress and accidents. Summary of the Invention

[0006] This invention provides a large-diameter, thick submarine cable and a cooling and conveying device to solve the problems of poor water resistance and crack resistance of submarine cables in the prior art.

[0007] In a first aspect, the present invention provides a large-diameter, thick submarine cable, comprising: a cable core, a cable wrapping layer, an inner sheath, an armor layer, and an outer sheath arranged sequentially from the inside to the outside;

[0008] The cable core includes an electrical unit and an optical unit, which are twisted together to form a cable. The electrical unit has a conductor, which is made of twisted monofilaments. The conductor has a multi-layer structure, and a semi-conductive resistive adhesive is provided between any two adjacent layers.

[0009] Both the inner and outer sheaths are made of medium-density insulating polyethylene. The inner sheath is pressurized and extruded onto the outside of the cable wrapping layer, and the outer sheath is pressurized and extruded onto the outside of the armor layer.

[0010] According to the large-diameter, thick submarine cable provided by the present invention, the electrical unit includes, from the inside out, the conductor, the conductor shielding layer, the conductor insulation layer, the insulation shielding layer, the first wrapping layer, the metal tape shielding layer, the second wrapping layer and the sheath layer, wherein the conductor insulation layer is made of ultra-clean water-tree resistant cross-linked polyethylene.

[0011] The large-diameter, thick submarine cable provided by the present invention has both the first wrapping layer and the second wrapping layer made of semi-conductive resistive water tape.

[0012] According to the large-diameter, thick submarine cable provided by the present invention, the metal strip shielding layer is wrapped around the outside of the first wrapping layer, and the second wrapping layer is wrapped around the outside of the metal strip shielding layer. The wrapping directions of the first wrapping layer and the second wrapping layer are both opposite to the wrapping direction of the metal strip shielding layer.

[0013] The large-diameter, thick submarine cable provided by the present invention includes an armor layer comprising an inner armor layer, a first armor wrapping layer, an outer armor layer, and a second armor wrapping layer arranged sequentially from the inside to the outside.

[0014] The large-diameter, thick submarine cable provided by the present invention has an inner armor layer and an outer armor layer made of galvanized medium-carbon metal wire, wherein the tensile strength of the galvanized medium-carbon metal wire is ≥650MPa.

[0015] The large-diameter, thick submarine cable provided by the present invention has an outer sheath comprising multiple areas of different colors.

[0016] In a second aspect, the present invention provides a cooling conveying device, comprising: a cooling tank and a conveying mechanism;

[0017] The cooling tank is used to hold cooling water to cool the outer sheath of the cable;

[0018] The conveying mechanism includes a drive assembly and a belt. The drive assembly is connected to the belt. The belt is placed in the cooling water in the cooling tank. The belt has a groove that is adapted to the outer protective layer.

[0019] According to the cooling conveying device provided by the present invention, the groove is arranged along the conveying direction of the belt.

[0020] According to the cooling conveying device provided by the present invention, the belt is inclined and the end of the belt with a lower height is located in the middle of the cooling tank.

[0021] The large-diameter, thick submarine cable and cooling conveying device of the present invention uses medium-density polyethylene (MDPE) as the inner and outer sheaths, thereby ensuring that the inner and outer sheaths maintain good structural strength and resistance to environmental stress cracking over a long period of time, preventing water ingress or cracking of the submarine cable due to the impact of water flow. The inner and outer sheaths are made by pressure extrusion, which allows the MPE to fill the gaps on the outer side of the cable wrapping layer and the outer side of the armor wrapping layer, increasing the water-blocking performance of the submarine cable and preventing slippage of the inner and outer sheaths. This effectively solves the problem of poor water-blocking performance and crack resistance of submarine cables in the prior art. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of a large-diameter, large-thickness submarine cable provided in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the structure of the electrical unit provided in an embodiment of the present invention;

[0025] Figure 3 This is a schematic diagram of the cooling conveying device provided in an embodiment of the present invention;

[0026] Figure 4 This is a top view of the cooling conveying device provided in an embodiment of the present invention.

[0027] Figure label:

[0028] 1. Cable core; 11. Electrical unit; 111. Conductor; 112. Conductor shielding layer; 113. Conductor insulation layer; 114. Insulation shielding layer; 115. First wrapping layer; 116. Metal strip shielding layer; 117. Second wrapping layer; 118. Sheath layer; 12. Optical unit;

[0029] 2. Cable wrapping layer; 3. Inner sheath layer;

[0030] 4. Armor layer; 41. Inner armor layer; 42. First armor strap layer; 43. Outer armor layer; 44. Second armor strap layer;

[0031] 5. Outer protective layer; 6. Cooling tank;

[0032] 7. Conveying mechanism; 71. Drive assembly; 72. Belt. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0034] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0035] In the description of the embodiments of the present invention, it should be noted that the terms "center", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0037] The following is combined with Figures 1 to 4 This invention describes a large-diameter, thick submarine cable and a cooling and conveying device.

[0038] like Figures 1 to 2As shown, a large-diameter, thick submarine cable includes: a cable core 1, a cable wrapping layer 2, an inner sheath 3, an armor layer 4, and an outer sheath 5 arranged sequentially from the inside out; the cable core 1 includes an electrical unit 11 and an optical unit 12, which are twisted together to form a cable; the electrical unit 11 has a conductor 111, which is formed by multiple monofilaments wrapped together; the conductor 111 has a multi-layer structure, and a semi-conductive resistive adhesive is provided between any two adjacent layers; the inner sheath 3 and the outer sheath 5 are both made of medium-density insulated polyethylene; the inner sheath 3 is pressurized and extruded onto the outside of the cable wrapping layer 2, and the outer sheath 5 is pressurized and extruded onto the outside of the armor layer.

[0039] Specifically, there is at least one electrical unit 11 and one optical unit 12. The optical unit 12 can be a conventional optical cable, which performs communication and other functions through the optical fiber inside. The conductor 111 is a tightly compressed circular water-blocking conductor made of copper monofilaments. Semiconductor resistive water adhesive is provided between any two adjacent layers of the conductor 111. The semiconductor resistive water adhesive can fill the gaps between the monofilaments and enhance the longitudinal water-blocking performance.

[0040] The inner side of the cable wrapping layer 2 is filled with water-blocking grease, which can fill the gaps between the electrical unit 11, the optical unit 12 and the cable wrapping layer 2, thus achieving a good water-blocking effect.

[0041] The inner sheath 3 and outer sheath 5 of the package protect the other internal components and also act as a water-blocking layer to prevent water ingress. Both the inner sheath 3 and outer sheath 5 are made of medium-density polyethylene (MDPE), which has good resistance to environmental stress cracking and long-term strength retention. Compared to conventional tube extrusion, the inner sheath 3 and outer sheath 5 are extruded. For example, MPE is extruded onto the outside of the armor layer 4. By applying sufficient pressure to the MPE, it fills the gaps on the surface of the armor layer 4, resulting in a better water-blocking effect for the final outer sheath 5. The arrangement of the inner sheath 3 can be the same as that of the outer sheath 5.

[0042] The large-diameter, thick submarine cable of the present invention uses medium-density polyethylene (MDPE) as the inner sheath 3 and outer sheath 5, thereby ensuring that the inner sheath 3 and outer sheath 5 maintain good structural strength and resistance to environmental stress cracking over a long period of time, preventing water ingress or cracking of the submarine cable due to the impact of water flow. The inner sheath 3 and outer sheath 5 are extruded under pressure, allowing the MPE to fill the gaps on the outer side of the cable wrapping layer 2 and the outer side of the armor layer 4, increasing the water-blocking performance of the submarine cable and preventing the inner sheath 3 and outer sheath 5 from slipping off, effectively solving the problem of poor water-blocking performance and crack resistance of submarine cables in the prior art.

[0043] like Figures 1 to 2As shown, in some embodiments, the electrical unit 11 includes a conductor 111, a conductor shielding layer 112, a conductor insulation layer 113, an insulation shielding layer 114, a first wrapping layer 115, a metal strip shielding layer 116, a second wrapping layer 117, and a sheath layer 118 arranged sequentially from the inside to the outside. The conductor insulation layer 113 is made of ultra-clean water-tree resistant cross-linked polyethylene.

[0044] Specifically, the conductor shielding layer 112 is made of semi-conductive cross-linked polyethylene shielding material, which is uniformly extruded onto the conductor 111 to prevent gaps from forming between the conductor 111 and the conductor insulation layer 113, thus preventing partial discharge. The conductor insulation layer 113 is made of ultra-clean water-tree resistant cross-linked polyethylene material, which is uniformly extruded onto the conductor shielding layer 112. The water-tree resistant cross-linked polyethylene material ensures that water trees do not form in the submarine cable when water enters, preventing the conductor insulation layer 113 from being extruded, thus ensuring the stability of the circuit.

[0045] The insulating shielding layer 114 is made of semi-conductive cross-linked polyethylene shielding material uniformly extruded onto the conductor insulation layer 113, uniformly creating an electric field on the outer surface of the conductor insulation layer 113 and protecting it from damage. The conductor shielding layer 112, conductor insulation layer 113, and insulating shielding layer 114 are produced using a three-layer co-extrusion method, i.e., the conductor shielding layer 112, conductor insulation layer 113, and insulating shielding layer 114 are extruded in one step, which greatly improves the roundness, smoothness, and density of the wire core, thereby improving the withstand voltage level and service life of the electrical unit 11.

[0046] The first wrapping layer 115 wraps around the insulation shielding layer 114. A colored strip is embedded inside the first wrapping layer 115 for color differentiation. The metal strip shielding layer 116 is wrapped around the first wrapping layer 115 in an overlapping manner using copper strips, with the wrapping direction opposite to that of the first wrapping layer 115. Compared with the conventional loose winding method of copper wires in dynamic submarine cables, the reverse wrapping and tightening of the metal strip shielding layer 116 can reduce the time and labor costs for adjusting the copper wires while meeting the short-circuit current requirements. Furthermore, after being squeezed by the sheath layer 118, the loosely wound copper wires are prone to sinking into the insulation shielding layer 114 under stress, causing the insulation shielding layer 114 to become concave and thinner. The second wrapping layer 117 wraps around the metal strip shielding layer 116 and tightens it, with the wrapping direction consistent with that of the first wrapping layer 115.

[0047] like Figures 1 to 2 As shown, in some embodiments, the first wrapping layer 115 and the second wrapping layer 117 are both semiconducting resistive water tapes.

[0048] like Figures 1 to 2 As shown, in some embodiments, the sheath layer 118 uses a medium-density insulating sheath material, specifically medium-density insulating polyethylene, and the sheath layer 118 is extruded onto the second wrapping layer 117 to form a water-blocking layer.

[0049] like Figures 1 to 2 As shown, in some embodiments, the cable wrapping layer 2 is an adhesive cotton cloth tape, which is used to tighten the cable core 1.

[0050] like Figures 1 to 2 As shown, in some embodiments, the armor layer 4 includes an inner armor layer 41, a first armor strap layer 42, an outer armor layer 43, and a second armor strap layer 44 arranged sequentially from the inside to the outside.

[0051] Specifically, by setting up a double-layer armor structure with an inner armor layer 41 and an outer armor layer 43, the structural strength of the submarine cable is effectively increased. The inner armor layer 41 and the outer armor layer 43 are both made of galvanized medium carbon metal wire, and the tensile strength of the galvanized medium carbon metal wire is ≥650MPa.

[0052] like Figures 1 to 2 As shown, in some embodiments, both the first armor strap layer 42 and the second armor strap layer 44 are made of PBT straps, and the first armor strap layer 42 and the second armor strap layer 44 are wrapped around the outer sides of the inner armor layer 41 and the outer armor layer 43 respectively in an overlapping wrapping manner. The PBT straps have high strength and high toughness, which can tighten the armor layer 4 while preventing the armor layer 4 from being worn through during the transfer process.

[0053] In some embodiments, the outer sheath 5 includes multiple areas of different colors.

[0054] Specifically, the main color of the outer protective layer 5 is yellow, and a black auxiliary color band is embedded on the outer protective layer 5, so that the outer protective layer 5 has two color areas of yellow and black. The auxiliary color band can serve as an identifier, making it easier for workers to judge the relative positions of the components inside the outer protective layer 5.

[0055] like Figures 3 to 4 As shown, the present invention also provides a cooling conveying device, including: a cooling tank 6 and a conveying mechanism 7; the cooling tank 6 is used to contain cooling water for cooling the outer sheath 5 of the cable; the conveying mechanism 7 includes a drive assembly 71 and a belt 72, the drive assembly 71 is connected to the belt 72, the belt 72 is disposed in the cooling water in the cooling tank 6, and the belt 72 is provided with a groove that is adapted to the outer sheath 5.

[0056] Specifically, the drive assembly 71 includes a motor, multiple chain-gear transmission components and multiple guide wheels. The multiple guide wheels are spaced apart in a straight line. The belt 72 is sleeved on the multiple guide wheels. Adjacent guide wheels are connected by a chain-gear transmission component. The motor is connected to one of the guide wheels. The motor drives the guide wheel to rotate, thereby enabling the belt 72 to transport the outer protective layer 5.

[0057] Because the outer sheath 5, being thick, requires a long cooling time, in existing production processes, the incompletely cooled outer sheath 5 is prone to deformation during transport, resulting in poor roundness. This leads to gaps between the outer sheath and the seals when installing them on the submarine cable, causing water ingress. However, waiting for the outer sheath to fully cool before transport reduces production efficiency. This embodiment utilizes a cooling transport device. After the outer sheath 5 is prepared, the submarine cable enters the cooling tank 6, where cooling water cools the outer sheath 5. The initially cooled submarine cable moves onto the conveyor belt 72. Having undergone initial cooling, the outer sheath 5 on the conveyor belt 72 is less prone to deformation. Furthermore, the conveyor belt 72 is also within the cooling tank 6, allowing the outer sheath 5 to continue cooling and preventing deformation. The submarine cable on the conveyor belt 72 is positioned within a groove, with the groove wall tightly fitted to the outer sheath 5, preventing deformation due to incomplete cooling and ensuring proper roundness. This, in turn, prevents water ingress into the submarine cable.

[0058] like Figures 3 to 4 As shown, in some embodiments, the groove is arranged along the conveying direction of the belt 72, so that the conveying of the submarine cable by the belt 72 is not limited by the length of the submarine cable.

[0059] like Figures 3 to 4 As shown, in some embodiments, the belt 72 is inclined to make full use of the internal space of the cooling tank 6, allowing the outer protective layer 5 to remain in the cooling water for a longer period of time. The lower end of the belt 72 is located in the middle of the cooling tank 6, so that the outer protective layer 5 is initially cooled in the cooling water before moving onto the belt 72, preventing deformation of the outer protective layer 5. The higher end of the belt 72 is located at the end of the cooling tank 6.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A large-diameter, thick submarine cable, characterized in that, include: The cable core, cable wrapping layer, inner sheath, armor layer and outer sheath are arranged sequentially from the inside to the outside; The cable core includes an electrical unit and an optical unit, which are twisted together to form a cable. The electrical unit has a conductor, which is made of twisted monofilaments. The conductor has a multi-layer structure, and a semi-conductive resistive adhesive is provided between any two adjacent layers. Both the inner and outer sheaths are made of medium-density insulating polyethylene. The inner sheath is pressurized and extruded onto the outside of the cable wrapping layer, and the outer sheath is pressurized and extruded onto the outside of the armor layer.

2. The large-diameter, thick submarine cable according to claim 1, characterized in that, The electrical unit includes, from the inside out, the conductor, conductor shielding layer, conductor insulation layer, insulation shielding layer, first wrapping layer, metal strip shielding layer, second wrapping layer and sheath layer, wherein the conductor insulation layer is made of ultra-clean water-tree resistant cross-linked polyethylene.

3. The large-diameter, large-thickness submarine cable according to claim 2, characterized in that, The conductor shielding layer is made of semi-conductive cross-linked polyethylene shielding material, which is uniformly extruded onto the conductor. And / or, the conductor insulation layer is uniformly extruded onto the conductor shielding layer using ultra-clean, water-tree resistant, cross-linked polyethylene material; And / or, the insulating shielding layer is made of semi-conductive cross-linked polyethylene shielding material uniformly extruded onto the conductor insulation layer.

4. The large-diameter, thick submarine cable according to claim 2, characterized in that, Both the first wrapping layer and the second wrapping layer are semiconducting resistive water tape components.

5. The large-diameter, thick submarine cable according to claim 2, characterized in that, The metal strip shielding layer is wrapped around the outside of the first wrapping layer, and the second wrapping layer is wrapped around the outside of the metal strip shielding layer. The wrapping directions of the first wrapping layer and the second wrapping layer are both opposite to the wrapping direction of the metal strip shielding layer.

6. The large-diameter, large-thickness submarine cable according to claim 5, characterized in that, The first wrapping layer has an embedded color strip for color differentiation, and the metal strip shielding layer is wrapped around the first wrapping layer in an overlapping manner using copper strips.

7. The large-diameter, thick submarine cable according to claim 1, characterized in that, The armor layer includes an inner armor layer, a first armor strap layer, an outer armor layer, and a second armor strap layer arranged sequentially from the inside out.

8. The large-diameter, large-thickness submarine cable according to claim 7, characterized in that, The inner side of the cable wrapping layer is filled with water-resistant grease. And / or, both the first armor strap layer and the second armor strap layer are made of PBT straps, and the first armor strap layer and the second armor strap layer are wrapped around the outside of the inner armor layer and the outer armor layer respectively in an overlapping wrapping manner.

9. The large-diameter, large-thickness submarine cable according to claim 7, characterized in that, Both the inner and outer armor layers are made of galvanized medium-carbon metal wire, and the tensile strength of the galvanized medium-carbon metal wire is ≥650MPa.

10. The large-diameter, large-thickness submarine cable according to claim 1, characterized in that, The outer protective layer includes multiple areas of different colors.

11. A cooling conveying device, characterized in that, include: Cooling tanks and conveying mechanisms; The cooling tank is used to contain cooling water for cooling the outer sheath of the large-diameter, thick submarine cable as described in any one of claims 1-10; The conveying mechanism includes a drive assembly and a belt. The drive assembly is connected to the belt. The belt is placed in the cooling water in the cooling tank. The belt has a groove that is adapted to the outer protective layer.

12. The cooling conveying device according to claim 11, characterized in that, The groove is arranged along the conveying direction of the belt.

13. The cooling conveying device according to claim 11, characterized in that, The belt is inclined, and the lower end of the belt is located in the middle of the cooling tank.

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