Low-loss lightweight submarine cable

Abstract

The present application relates to the technical field of cables, and provides a low-loss lightweight submarine cable. The low-loss lightweight submarine cable comprises: power cable cores, wherein each power cable core comprises a conductor cluster and a protective structure encasing the conductor cluster, the conductor cluster comprises a plurality of stranded water-blocking conductors, and each water-blocking conductor comprises a conductor wire and an insulating film layer attached to the outer wall of the conductor wire; an optical fiber unit; and a sheathing structure that encases the outer peripheries of the power cable cores and the optical fiber unit, wherein the sheathing structure comprises at least one armor layer, the armor layer comprises a plurality of helically stranded armor elements, and each armor element comprises a metal wire and a coating layer attached to the outer wall of the metal wire. The low-loss lightweight submarine cable provided by the present application has the characteristics of low loss and light weight, and can be used in deep-water and large-capacity alternating current submarine cable engineering.

Description

A low-loss lightweight submarine cable

[0001] This application claims priority to Chinese Patent Application No. 202411907111.0, filed on December 23, 2024, entitled “A Low-Loss Lightweight Submarine Cable”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of cable technology, and in particular to a low-loss lightweight submarine cable. Background Technology

[0003] With the rapid development of the marine power transmission sector and the advancement of the "dual carbon" policy, submarine cables are increasingly widely used in marine wind energy and cross-sea power transmission, and have become an important infrastructure for achieving efficient transmission of renewable energy.

[0004] Currently, the design and application of submarine cables are gradually evolving towards longer distances, lower losses, and lighter weight. Traditional submarine cables typically use copper wires as conductors, with the wires closely packed and interconnected, which easily leads to the skin effect. This causes the current to concentrate mainly at the edges of the conductor during operation, rather than being evenly distributed, thus increasing AC resistance and energy loss. Furthermore, the armor layer of current submarine cables is usually composed of galvanized steel wire or copper wire, which, while providing excellent mechanical strength, also increases armor loss and the weight of the submarine cable. Summary of the Invention

[0005] In view of the above problems, this application provides a low-loss lightweight submarine cable. The low-loss lightweight submarine cable features low loss and lightweight design, and can be used in deep-water, high-capacity AC submarine cable projects.

[0006] To achieve the above objectives, the embodiments of this application provide the following technical solutions:

[0007] This application provides a low-loss lightweight submarine cable, comprising: a power cable core, the power cable core including a conductor cluster and a protective structure covering the conductor cluster, the conductor cluster including multiple stranded water-blocking conductors, the water-blocking conductors including conductor wires and an insulating film layer attached to the outer wall of the conductor wires; an optical fiber unit; and a sheathing structure covering the outer periphery of the power cable core and the optical fiber unit, the sheathing structure including at least one armor layer, the armor layer including multiple spirally stranded armor units, the armor unit including metal wires and a coating layer attached to the outer wall of the metal wires.

[0008] In one possible implementation, the insulating resistivity of the insulating film layer is greater than or equal to 400 MΩ·cm, and / or the thickness of the insulating film layer is less than or equal to 300 μm.

[0009] In one possible implementation, the insulating film layer is a polyethylene layer.

[0010] In one possible implementation, the coating layer of the armor unit is a corrosion-resistant and conductive layer, the neutral salt spray corrosion rate of which is less than or equal to 0.001 mm / a, and the salt water immersion corrosion rate is less than or equal to 0.001 mm / a.

[0011] In one possible implementation, the metal wires of the armor unit are aluminum alloy wires.

[0012] In one possible implementation, the protective structure includes an insulating layer, a water-blocking layer, and a non-metallic sheath layer arranged sequentially from the inside out.

[0013] In one possible implementation, the power cable core is provided with at least two cores, a filling layer is provided between adjacent power cable cores, and the optical fiber unit is disposed within the filling layer.

[0014] In one possible implementation, the optical fiber unit includes: an optical unit and a protective structure covering the outside of the optical unit.

[0015] In one possible implementation, the protective structure includes an inner sheath, an optical unit armor layer, a wrapping layer, and an outer sheath arranged sequentially from the inside out.

[0016] In one possible implementation, the covering structure further includes, from the inside out: a wrapping layer, an inner liner layer, and an outer jacket layer, with the armor layer located between the inner liner layer and the outer jacket layer.

[0017] The low-loss lightweight submarine cable provided in this application includes a power cable core, optical fiber units, and a sheathing structure. The power cable core includes a conductor cluster and a protective structure covering the conductor cluster. The conductor cluster includes multiple stranded water-blocking conductors, each consisting of conductor wires and an insulating film layer attached to the outer wall of the conductor wires. The insulating film layer attached to the outer wall of the conductor wires not only provides physical protection for the conductor wires but also effectively suppresses the skin effect and proximity effect, reduces the concentrated distribution of current on the conductor wire surface, and lowers AC resistance, thereby reducing energy loss during power transmission and improving the transmission efficiency of the water-blocking conductors. The sheathing structure covers the outer periphery of the power cable core and optical fiber units. The sheathing structure includes at least one armor layer, which includes multiple spirally stranded armor units. Each armor unit includes metal wires and a coating layer attached to the outer wall of the metal wires. Thus, by adding a coating layer outside the metal wires, the weight of the submarine cable can be significantly reduced while ensuring its bending and tensile strength. Therefore, the low-loss lightweight submarine cable provided in this application has the characteristics of low loss and lightweight, and is suitable for AC submarine cable projects with large water depth and large capacity. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application 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 application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 is a schematic diagram of the structure of the low-loss lightweight submarine cable provided in the embodiment of this application.

[0020] Explanation of reference numerals in the attached diagram: 10-Low-loss lightweight submarine cable; 100-Power cable core; 200-Optical fiber unit; 300-Sheathing structure; 400-Filling layer; 110-Conductor cluster; 120-Protective structure; 210-Optical unit; 220-Protective structure; 310-Armor layer; 320-Wrapping layer; 330-Inner liner layer; 340-Outer sheath layer; 111-Water-blocking conductor; 121-Insulation layer; 122-Water-blocking layer; 123-Non-metallic sheath layer; 124-Conductor shielding layer; 125-Insulating shielding layer; 126-Metallic shielding layer; 311-Armored unit; 221-Inner sheath; 222-Optical unit armor layer; 223-Wrapping layer; 224-Outer sheath. Detailed Implementation

[0021] As described in the background section, with the increasing global demand for renewable energy and the accelerated development of marine resources, the application scope of submarine cables is constantly expanding. Submarine cables not only play an important role in transoceanic power transmission and communication, but also serve as a key component in connecting offshore wind farms and offshore oil and gas platforms. The widespread application of submarine cables promotes the interconnection of global energy networks, supports long-distance, high-capacity power and data transmission, and has become an indispensable part of modern marine engineering and infrastructure construction.

[0022] Currently, traditional submarine cables typically use copper wire as the conductor. The tightly packed and interconnected copper wires result in a significant skin effect, concentrating current primarily at the conductor edges and increasing AC resistance and losses. Furthermore, the armor layer of traditional submarine cables generally uses galvanized steel or copper wire. While galvanized steel wire offers good mechanical strength, its magnetic properties lead to high armor losses. Copper wire, although possessing excellent corrosion resistance and low losses, is limited by its high cost. In addition, the high density of steel and copper wires increases the weight of the submarine cable, raising transportation and laying costs and increasing the risk of damage.

[0023] In addition, CN217061582U discloses a tensile-resistant, collision-resistant, low-loss cable that uses a single silver-plated copper wire as the inner conductor, reducing conductor attenuation. Furthermore, the cable possesses superior tensile strength through a silver-plated copper wire braided layer and an aramid fiber braided layer, followed by an extruded polyurethane outer sheath. However, the high cost of the silver-plated alloy conductor limits its large-scale application in long-length submarine cables.

[0024] CN115831483A discloses a method for manufacturing a low-loss, large-section conductor and the low-loss, large-section conductor itself, and introduces a method for manufacturing such a conductor. The method involves drawing a copper rod into a circular copper single wire. Then, a first layer of enameled wire is sprayed onto the outer circumference of the circular copper single wire, and six layers of corrugated copper single wire conductors are sequentially stranded from the inside out, with the first to fifth layers being sprayed with enameled wire after stranding. This method results in a tightly packed conductor with a smooth, round surface, ensuring uniform electric field distribution and improving cable lifespan. However, the enameled wire conductor does not have an enameled layer applied to all the single wires.

[0025] In view of this, embodiments of this application provide a low-loss lightweight submarine cable, including a power cable core, an optical fiber unit, and a sheathing structure. The power cable core includes a conductor cluster and a protective structure covering the conductor cluster. The conductor cluster includes multiple stranded water-blocking conductors, each of which includes conductor wires and an insulating film layer attached to the outer wall of the conductor wires. The insulating film layer attached to the outer wall of the conductor wires not only provides physical protection for the conductor wires but also effectively suppresses the skin effect and proximity effect, reduces the concentrated distribution of current on the conductor wire surface, and lowers AC resistance, thereby reducing energy loss during power transmission and improving the transmission efficiency of the water-blocking conductors. The sheathing structure covers the periphery of the power cable core and the optical fiber unit. The sheathing structure includes at least one armor layer, which includes multiple spirally stranded armor units. Each armor unit includes metal wires and a coating layer attached to the outer wall of the metal wires. Thus, by adding a coating layer outside the metal wires, the weight of the submarine cable can be significantly reduced while ensuring its bending and tensile strength. Therefore, the low-loss lightweight submarine cable provided in this application has the characteristics of low loss and lightweight, and is suitable for AC submarine cable projects with large water depth and large capacity.

[0026] To make the above-mentioned objectives, features, and advantages of the embodiments of this application more apparent and understandable, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0027] Figure 1 is a schematic diagram of the structure of the low-loss lightweight submarine cable provided in an embodiment of this application. Referring to Figure 1, an embodiment of this application provides a low-loss lightweight submarine cable 10. The low-loss lightweight submarine cable 10 achieves a low-loss and lightweight design, improves power transmission efficiency, and reduces installation and maintenance costs.

[0028] The low-loss lightweight submarine cable 10 can be used in AC submarine cable applications of 500kV and below, primarily for power transmission in fixed wind turbine and offshore wind power projects. Furthermore, the low-loss lightweight submarine cable 10 possesses optoelectronic composite characteristics, enabling simultaneous transmission of power and communication signals, thereby enhancing the monitoring and data transmission capabilities of offshore wind farms. Its flexibility makes it suitable not only for offshore wind power projects but also for other applications requiring submarine power transmission, demonstrating broad application potential and market prospects.

[0029] Referring to Figure 1, the low-loss lightweight submarine cable 10 includes a power cable core 100, an optical fiber unit 200, and a sheathing structure 300. The power cable core 100 is responsible for the efficient transmission of electrical energy, delivering power from the power source to the load. The optical fiber unit 200 is responsible for the transmission of optical signals, providing a high-speed data transmission channel to ensure fast and reliable data transmission, meeting the needs of modern communication. The sheathing structure 300 covers the outer periphery of the power cable core 100 and the optical fiber unit 200, protecting the low-loss lightweight submarine cable 10 from physical damage caused by external mechanical forces such as friction from bottom rocks and sediments, and fishing activities. Simultaneously, it prevents seawater and other corrosive substances from eroding the internal structure of the low-loss lightweight submarine cable 10, extending its service life. Furthermore, during the laying and retrieval of the low-loss lightweight submarine cable 10, the sheathing structure 300 provides additional tensile strength, reducing the risk of breakage due to external forces.

[0030] The power cable core 100 includes a conductor cluster 110, which is composed of multiple stranded and wound water-blocking conductors 111. Each water-blocking conductor 111 includes a conductor wire (not shown in the figure) and an insulating film layer (not shown in the figure), with the insulating film layer attached to the outer wall of the conductor wire. The conductor wire is a core component for power transmission, and it can be made of copper, aluminum, or aluminum alloy; this embodiment does not impose specific limitations on this.

[0031] It should be noted that when multiple conductor wires are closely arranged, their electromagnetic fields interact, leading to proximity and skin effects. Therefore, this embodiment increases the distance between conductors by wrapping each conductor wire with an insulating film, thereby reducing the impact of proximity and skin effects. This helps to make the current distribution more uniform in each conductor, reducing AC resistance and power loss, and improving power transmission efficiency. Furthermore, the insulating film also enhances the mechanical strength and corrosion resistance of the conductor wires, extending the service life of the low-loss lightweight submarine cable 10, enabling it to operate efficiently and reliably in complex marine environments.

[0032] The insulating resistivity of the insulating film layer can be greater than or equal to 400 MΩ·cm, and the thickness of the insulating film layer can be less than or equal to 300 μm. This high insulating resistivity ensures that the insulating film layer can effectively prevent current leakage and provide reliable electrical isolation. The thinner insulating film layer helps reduce the overall size and weight of the low-loss lightweight submarine cable 10, giving it greater flexibility and making it easier to bend and install.

[0033] In one possible implementation, the insulating film layer can be obtained by immersing a conductor wire in a coating solution. Specifically, a coating solution is first prepared by dissolving polyethylene material in a toluene-containing solution at 60°C in an oxygen-free environment. The conductor wire is then immersed in the coating solution, allowing the coating solution to coat the outer surface of the conductor wire. Next, the conductor wire coated with the coating solution is passed through a heating pipe, thereby forming a uniformly distributed insulating film on the surface of the conductor wire. In other words, the insulating film layer adhering to the conductor wire can be a polyethylene layer.

[0034] In addition, depending on the water depth and application requirements, water-blocking filling material (not shown in the figure) can also be provided in the gaps inside the conductor cluster 110. The water-blocking filling material can form a water barrier in the underwater environment, effectively preventing the intrusion of water, thereby ensuring the long-term stable operation and safety of the low-loss lightweight submarine cable 10.

[0035] Referring again to Figure 1, the power cable core 100 also includes a protective structure 120 covering the conductor cluster 110. The protective structure 120 includes an insulation layer 121, a water-blocking layer 122, and a non-metallic sheath layer 123 arranged sequentially from the inside to the outside.

[0036] Insulation layer 121 prevents current leakage and ensures the safe operation of power cable core 100. Therefore, the material of insulation layer 121 must have good electrical insulation properties, as well as appropriate mechanical strength and chemical stability. For example, cross-linked polyethylene, polypropylene, and other materials can be used as insulation materials.

[0037] It should be noted that a conductor shielding layer 124 may also be provided between the conductor cluster 110 and the insulation layer 121. The conductor shielding layer 124 can make the interface between the conductor cluster 110 and the insulation layer 121 as smooth as possible, thereby effectively eliminating irregularities and sharp point effects on the conductor surface. This design helps to avoid excessive concentration of electric field in specific areas, thereby reducing the problem of electric field intensity concentration in the power cable core 100 during operation, significantly improving the electrical performance and reliability of the power cable core 100, and ensuring the long-term stable operation of the power cable core 100.

[0038] In addition, an insulating shielding layer 125 may be provided outside the insulating layer 121 to ensure that the medium surface between the insulating layer 121 and the water layer is stable and smooth.

[0039] In one possible implementation, the conductor shielding layer 124, the insulation layer 121, and the insulation shielding layer 125 can be sequentially extruded and coated onto the surface of the conductor cluster 110 via a three-layer co-extrusion process. During the three-layer co-extrusion process, precise control is required to ensure that the conductor shielding layer 124, the insulation layer 121, and the insulation shielding layer 125 have uniform thickness, smooth surfaces, and are free of bubbles or pinholes, thereby guaranteeing the overall performance and long-term reliability of the power cable core 100.

[0040] The water-blocking layer 122 meets the requirements for longitudinal and radial water blocking at great water depths. Upon contact with water, the water-blocking layer 122 expands or forms a waterproof barrier, effectively preventing water from flowing radially or longitudinally along the power cable core 100. For example, the material of the water-blocking layer 122 can be semi-conductive resistive water tape, which meets both the electrical performance requirements of the power cable core 100 and provides water blocking and buffering functions. Furthermore, multiple layers of semi-conductive tape can be provided, and the semi-conductive tape can be wrapped around the outer periphery of the insulation layer 121 by overlapping and wrapping, with an overlap rate of 10% to 30%. That is, when the semi-conductive resistive water tape is wrapped around the power cable core 100, each turn partially overlaps the previous turn, with the overlap being 10% to 30% of the tape's width. This ensures that the semi-conductive resistive water tape tightly covers the outer surface of the insulation layer 121, forming a continuous, seamless protective layer.

[0041] In one possible implementation, a metal shielding layer 126 may be provided outside the water-blocking layer 122. The metal shielding layer 126 can conduct the capacitive current during normal operation and the short-circuit current during short circuits. It can also effectively shield electromagnetic interference, protect the power cable core 100 from lightning strikes, and homogenize the electric field to prevent axial discharge. In addition, the metal shielding layer 126 also ensures the safe grounding of the power cable core 100 to avoid excessive losses, thereby ensuring the stable operation and long-term reliability of the power cable core 100. Exemplarily, the metal shielding layer 126 can adopt structures such as alloy lead sheath, copper wire, copper strip, and aluminum-plastic composite strip. This embodiment does not impose specific limitations on this.

[0042] The non-metallic sheath layer 123 provides additional mechanical protection for the power cable core 100, resisting erosion from external environments such as corrosive substances and microbial activity. Therefore, the material of the non-metallic sheath layer 123 must possess good flexibility, corrosion resistance, and weather resistance to adapt to different application environments. For example, the non-metallic sheath layer 123 can be extruded semi-conductive polyethylene material.

[0043] A filler layer 400 may be provided outside the power cable core 100. The filler layer 400 can ensure the roundness and structural stability of the low-loss lightweight submarine cable 10. For example, the filler layer 400 can be made of polypropylene fiber rope. Polypropylene fiber rope has good flexibility and water resistance, which can enhance the mechanical cushioning performance of the low-loss lightweight submarine cable 10 and improve its flame retardant and impact resistance. Alternatively, the filler layer 400 can also be made of non-hygroscopic molded filler strip. Non-hygroscopic molded filler strips have the characteristic of not absorbing moisture, which helps to improve the moisture-proof performance and stability of the low-loss lightweight submarine cable 10. As long as the material can provide good support and high flame retardant and impact resistance, this embodiment does not limit the specific material of the filler layer 400.

[0044] It should be noted that, to meet different power transmission requirements, the power cable core 100 can be a single core or multiple cores. When multiple power cable cores 100 are used, a filler layer 400 is also provided between adjacent power cable cores 100. This ensures the stability of the low-loss lightweight submarine cable 10 during manufacturing and laying, and reduces electrical and mechanical problems caused by gaps between the power cable cores 100 during operation of the low-loss lightweight submarine cable 10.

[0045] The fiber optic unit 200 is disposed inside the filling layer 400, which protects the fiber optic unit 200 from compression. The fiber optic unit 200 provides a high-speed data transmission channel, supports broadband communication and Internet access, and can also be used in the condition monitoring and early warning system of the low-loss lightweight submarine cable 10.

[0046] Referring again to Figure 1, the optical fiber unit 200 includes an optical unit 210, which comprises multiple optical fibers (not shown) spirally twisted together. To enhance the structural stability of the optical fiber, a stainless steel tube (not shown) can be fitted over the fiber. The stainless steel tube provides a buffer space for the optical fiber, giving it a certain degree of flexibility when facing external impacts or vibrations. In other words, when the optical fiber encounters external impacts or vibrations, it can move moderately within the stainless steel tube, thereby reducing mechanical damage to the fiber and ensuring its stability and durability during the laying and use of the low-loss lightweight submarine cable 10.

[0047] It should be noted that, as an important component of the low-loss lightweight submarine cable 10, the optical fiber inside the optical unit 210 is highly susceptible to moisture and humidity. Moisture and humidity entering the optical unit 210 may cause corrosion of the stainless steel tube, thereby affecting the performance of the optical fiber. Therefore, the optical unit 210 can also be filled with a water-blocking material (not shown in the figure). For example, the water-blocking material can be a water-blocking fiber paste or a special grease. The water-blocking material can form a moisture barrier, preventing moisture from penetrating the interior of the optical unit 210, thus ensuring the transmission quality and service life of the optical unit 210.

[0048] In addition, the optical fiber unit 200 also includes a protective structure 220 covering the optical unit 210. The protective structure 220 includes an inner sheath 221, an optical unit armor layer 222, a wrapping tape layer 223, and an outer sheath 224 arranged sequentially from the inside to the outside.

[0049] The inner sheath 221 covers the outer periphery of the optical unit 210, protecting it from damage during the armoring process. Furthermore, the inner sheath 221 resists the intrusion of external corrosive media, thus providing primary protection for the optical fiber. The inner sheath 221 can be made of a relatively soft material, such as polyethylene or polyurethane.

[0050] The optical unit armor layer 222 can improve the compressive and tensile strength of the optical fiber unit 200, preventing the optical fiber unit 200 from being mechanically damaged during the laying or operation of the low-loss lightweight submarine cable 10. For example, the optical unit armor layer 222 can be made of stainless steel strip or steel wire braid.

[0051] The wrapping layer 223 can tightly wrap around the outer periphery of the optical unit armor layer 222, and can be used to fix the optical unit armor layer 222, preventing the optical unit armor layer 222 from loosening or shifting during the laying or operation of the low-loss lightweight submarine cable 10. In addition, the wrapping layer 223 can also provide additional protection for the optical fiber unit 200 to resist external abrasion.

[0052] The outer sheath 224 is disposed on the outer periphery of the wrapping layer 223, which can protect the optical fiber unit 200 from physical damage. Furthermore, the outer sheath 224 also has waterproof, shear-resistant, and tensile-resistant properties, thereby extending the service life of the optical fiber unit 200. In addition, the outer sheath 224 has strong impact resistance and can withstand various mechanical stresses that may be encountered during the laying of the low-loss lightweight submarine cable 10. For example, the outer sheath 224 can be formed by winding polypropylene rope, or it can be formed by extruding polyethylene, as long as the outer sheath 224 has good flexibility, chemical resistance, and abrasion resistance. This application embodiment does not impose specific limitations in this regard.

[0053] Referring again to Figure 1, the sheathing structure 300 covers the outer periphery of the power cable core 100 and the optical fiber unit 200. The sheathing structure 300 includes at least one armor layer 310. The armor layer 310 provides important mechanical protection for the low-loss lightweight submarine cable 10, preventing it from suffering physical damage such as impact and compression during laying and operation. Furthermore, the armor layer 310 provides the necessary tensile strength for the low-loss lightweight submarine cable 10. When the low-loss lightweight submarine cable 10 is subjected to tension or bending, the armor layer 310 can withstand the main tensile or compressive forces, protecting the power cable core 100 and the optical fiber unit 200 from damage. In addition, the armor layer 310 also has excellent corrosion resistance, effectively resisting seawater erosion and protecting the power cable core 100 and optical fiber unit 200 inside the low-loss lightweight submarine cable 10, thereby significantly extending the service life of the low-loss lightweight submarine cable 10.

[0054] Specifically, the armor layer 310 includes multiple spirally twisted armor units 311, and each armor unit 311 includes a metal wire (not shown in the figure) and a coating layer (not shown in the figure).

[0055] The metal wires are typically made of high-strength, corrosion-resistant materials to ensure durability and tensile strength in marine environments. For example, aluminum alloy wire can be used, which possesses excellent strength and corrosion resistance. Furthermore, the non-magnetic nature of aluminum alloy wire effectively reduces or even eliminates armor hysteresis losses during operation of the low-loss lightweight submarine cable 10. Of course, the lightweight nature of aluminum alloy wire also helps reduce the overall weight of the low-loss lightweight submarine cable 10, lowering installation and maintenance costs and improving its operability and flexibility in complex marine environments.

[0056] The coating layer, attached to the outer wall of the metal wire, possesses excellent corrosion resistance and electrical conductivity, providing reliable protection for the low-loss lightweight submarine cable 10 in complex marine environments. The coating layer can be made of corrosion-resistant and wear-resistant materials to block the erosion of seawater and other corrosive substances. For example, the coating layer can be a corrosion-resistant conductive layer. Specifically, the corrosion-resistant conductive layer exhibits a salt spray corrosion rate and a salt water immersion corrosion rate both less than or equal to 0.001 mm / a. This means that in harsh marine environments, the corrosion-resistant conductive layer can effectively resist the erosion of salt spray and salt water, significantly extending the service life of the low-loss lightweight submarine cable 10.

[0057] In addition, the anti-corrosion conductive layer also has excellent conductivity, which helps to distribute current evenly and reduce the risk of local current concentration, thereby reducing the resistance loss of the low-loss lightweight submarine cable 10 during operation and improving the electrical performance and transmission efficiency of the low-loss lightweight submarine cable 10.

[0058] Compared to the commonly used galvanized steel wire as the armor layer in current submarine cables, the low-loss lightweight submarine cable 10 of this application uses aluminum alloy wire combined with a coating layer as the armor layer 310. This design reduces the weight of the low-loss lightweight submarine cable 10 by 10%-20%, thereby simplifying installation and maintenance and reducing operating costs. In addition, the coating layer provides extra corrosion protection, enhances the wear resistance and adhesion of the aluminum alloy wire, prevents wear under dynamic marine conditions, and ensures the long-term reliability and performance stability of the low-loss lightweight submarine cable 10 under harsh conditions, enabling it to be used in deep water environments of 3000 meters and below.

[0059] Of course, to further enhance the corrosion resistance and water resistance of the low-loss lightweight submarine cable 10, the outer surface of the armor layer 310 can also be coated with a water-blocking material (not shown in the figure). For example, the water-blocking material can be asphalt, which effectively prevents the intrusion of seawater and other corrosive substances, contributing to the stability and reliability of the low-loss lightweight submarine cable 10 during long-term operation. In addition, asphalt has good adhesion and flexibility, so the asphalt coating will not easily crack or peel off when the low-loss lightweight submarine cable 10 is bent or subjected to external pressure, improving the adaptability of the low-loss lightweight submarine cable 10 in complex marine environments.

[0060] In one possible implementation, the covering structure 300 may further include a wrapping layer 320, which can tightly wrap around the outside of the filler layer 400 to enhance the strength and stability of the low-loss lightweight submarine cable 10 and prevent structural slippage and displacement. An armor layer 310 is disposed outside the wrapping layer 320.

[0061] For example, the wrapping layer 320 can be made of a thin, high-strength coated fabric tape. The thinness of the coated fabric tape ensures that the wrapping layer 320 does not significantly increase the overall diameter and weight of the low-loss lightweight submarine cable 10, thus maintaining the lightweight characteristics of the low-loss lightweight submarine cable 10. Meanwhile, the high strength of the wrapping layer 320 provides excellent tensile strength and abrasion resistance, effectively resisting mechanical shocks and wear from the external environment, ensuring the durability and reliability of the low-loss lightweight submarine cable 10 under dynamic marine conditions.

[0062] Referring again to Figure 1, an inner lining layer 330 may be provided outside the wrapping layer 320, located between the wrapping layer 320 and the armor layer 310. The inner lining layer 330 can further prevent moisture penetration. Furthermore, since the armor layer 310 is relatively rigid, the inner lining layer 330 can provide an additional barrier between the wrapping layer 320 and the armor layer 310, reducing direct friction between them and preventing wear caused by the armor layer 310 on the wrapping layer 320. For example, the inner lining layer 330 may be made of multiple polypropylene fiber ropes wound around the outer surface of the wrapping layer 320.

[0063] In addition, the sheathing structure 300 may also include an outer sheath layer 340, which is the outermost layer of the sheathing structure 300 and surrounds the armor layer 310. The outer sheath layer 340 can prevent the low-loss lightweight submarine cable 10 from physical damage such as impact or abrasion.

[0064] The outer sheath 340 can be multi-layered. For example, the outer sheath 340 can be formed by winding two layers of polypropylene fiber ropes with opposite twist directions around the outside of the armor layer 310. In this way, the polypropylene fiber ropes have excellent corrosion resistance and tensile strength, providing mechanical protection for the low-loss lightweight submarine cable 10. The staggered twist directions help improve structural stability, prevent interlayer slippage and displacement, and make the structure more compact, reducing gaps and preventing the penetration of external substances, further enhancing the overall durability and reliability of the low-loss lightweight submarine cable 10.

[0065] The various embodiments or implementation methods described in this specification are presented in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0066] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application 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 or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A low-loss lightweight submarine cable, characterized in that, include: The power cable core includes a conductor cluster and a protective structure covering the conductor cluster. The conductor cluster includes multiple stranded and wound water-blocking conductors. The water-blocking conductor includes conductor wires and an insulating film layer attached to the outer wall of the conductor wires. Fiber optic unit; An overlay structure is used to cover the outer periphery of a power cable core and an optical fiber unit. The overlay structure includes at least one armor layer, which includes multiple spirally twisted armor units. Each armor unit includes a metal wire and a coating layer attached to the outer wall of the metal wire.

2. The low-loss lightweight submarine cable according to claim 1, characterized in that, The insulating resistivity of the insulating film layer is greater than or equal to 400 MΩ·cm, and / or the thickness of the insulating film layer is less than or equal to 300 μm.

3. The low-loss lightweight submarine cable according to claim 1, characterized in that, The insulating film layer is a polyethylene layer.

4. The low-loss submarine cable according to any one of claims 1-3, characterized in that, The coating layer of the armor unit is a corrosion-resistant and conductive layer. The neutral salt spray corrosion rate of the corrosion-resistant and conductive layer is less than or equal to 0.001 mm / a, and the salt water immersion corrosion rate is less than or equal to 0.001 mm / a.

5. The low-loss submarine cable according to any one of claims 1-3, characterized in that, The metal wires of the armor unit are aluminum alloy wires.

6. The low-loss submarine cable according to any one of claims 1-3, characterized in that, The protective structure includes an insulating layer, a water-blocking layer, and a non-metallic sheath layer arranged sequentially from the inside out.

7. The low-loss submarine cable according to any one of claims 1-3, characterized in that, The power cable core is provided with at least two cores, and a filling layer is provided between adjacent power cable cores. The optical fiber unit is disposed within the filling layer.

8. The low-loss submarine cable according to any one of claims 1-3, characterized in that, The optical fiber unit includes: an optical unit and a protective structure covering the outside of the optical unit.

9. The low-loss submarine cable according to claim 8, characterized in that, The protective structure includes, from the inside out, an inner sheath, an optical unit armor layer, a wrapping layer, and an outer sheath.

10. The low-loss submarine cable according to any one of claims 1-3, characterized in that, The covering structure also includes a wrapping layer, an inner lining layer, and an outer sheath layer arranged from the inside out, with the armor layer located between the inner lining layer and the outer sheath layer.

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