A weather-resistant and fatigue-resistant offshore wind power cable structure and method

Abstract

This invention discloses a weather-resistant and fatigue-resistant offshore wind power cable structure and method, which solves the problem in the prior art where poor water-blocking performance of wind power cable structures leads to water tree formation in the conductor insulation layer due to moisture intrusion, resulting in a gradual deterioration of insulation performance. It has the beneficial effect of improving overall water-blocking performance and fatigue resistance. The specific solution is as follows: A weather-resistant and fatigue-resistant offshore wind power cable structure includes, from the inside to the outside, a conductor unit, a metal sealing sheath, a water-blocking buffer layer, an armor layer, and an outer sheath. The conductor unit is provided in at least one set, and a conductor core is provided inside the conductor unit. The conductor core is filled with water-blocking paste, and the conductor core is covered with a water-blocking tape, making the conductor core a water-blocking composite structure. The metal sealing sheath is a lead alloy sheath, which is covered on the outside of the conductor unit by an extrusion molding process to achieve radial absolute water blocking. The water-blocking buffer layer includes a radial water-blocking tape and an elastic buffer layer arranged from the inside to the outside.

Description

Technical Field

[0001] This invention relates to the field of cable structure technology, and in particular to a weather-resistant and fatigue-resistant offshore wind power cable structure. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] As an important component of clean energy, offshore wind power is expanding in scale and its operating areas are gradually extending into the deep sea. Offshore wind power cables, as the core carrier of power transmission, need to operate for extended periods in extreme marine environments characterized by high salt spray, high humidity, strong ocean currents, repeated bending and twisting, and drastic temperature differences, placing stringent requirements on structural stability, weather resistance, and fatigue resistance.

[0004] Existing offshore wind power cables have the following technical defects: The overall structure mainly consists of an outer sheath, which blocks water. However, the overall water-blocking capacity is generally low, making the insulation layer of the conductor susceptible to water intrusion and water tree formation, which leads to a gradual deterioration of the insulation performance. Moreover, the conductor unit usually relies solely on water-blocking tape for water blocking without other water-blocking units to assist in improving the water-blocking performance. As a result, the water-blocking capacity of the entire wind power cable needs to be improved, which results in a shorter cable lifespan. Dynamic submarine cables (suitable for floating wind power) are prone to fatigue damage due to repeated bending and twisting under the action of waves and floating bodies. Filling the outside of the conductor with water-blocking paste does not improve the conductor's bending resistance. In particular, peeling or cracks are likely to occur at the interface between the insulation layer and the shielding layer and armor layer. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a weather-resistant and fatigue-resistant offshore wind power cable structure that improves the cable structure's water-blocking performance, fatigue resistance, and mechanical properties, and prevents marine organisms from attaching and causing damage.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: A weather-resistant and fatigue-resistant offshore wind power cable structure includes, from the inside out, a conductor unit, a metal sealing sheath, a water-blocking buffer layer, an armor layer, and an outer sheath. The conductor unit is provided in at least one set, with a conductor core inside the conductor unit. The conductor core is filled with water-blocking paste, and the conductor core is covered with a water-blocking tape, making the conductor core a water-blocking composite structure. The metal sealing sheath is a metal alloy sheath, which is applied to the outside of the conductor unit by an extrusion molding process to achieve absolute radial water blocking. The water-blocking buffer layer includes a radial water-blocking tape and an elastic buffer layer arranged from the inside out.

[0007] As described above, in a weather-resistant and fatigue-resistant offshore wind power cable structure, the metal alloy sheath is made of lead-tin-antimony alloy, with a lead mass fraction of 80%-92%, a tin mass fraction of 5%-13%, and an antimony mass fraction of 3%-7%.

[0008] As described above, in a weather-resistant and fatigue-resistant offshore wind power cable structure, the radial water-blocking strip is an aluminum-plastic composite water-blocking strip with an overlap rate of ≥20%; the elastic buffer layer is a water-swellable rubber layer, which can fill the tiny recesses on the surface of the lead alloy sheath.

[0009] The weather-resistant and fatigue-resistant offshore wind power cable structure described above includes a water-blocking paste comprising base oil, water-absorbing and swelling resin, gelling agent, antioxidant, and dispersant, wherein the mass fractions of the base oil, water-absorbing and swelling resin, gelling agent, antioxidant, and dispersant are 70%-81%, 10%-13%, 8%-12%, 0.5%-1.2%, and 1.5%-3.0%, respectively.

[0010] As described above, the weather-resistant and fatigue-resistant offshore wind power cable structure has an outer sheath that is a modified polyethylene layer. The outer sheath includes polyethylene, with 3%-5% by mass of an environmentally friendly copper ion antifouling agent added to the polyethylene. The polyethylene also contains 2%-4% by mass of carbon black and 1%-3% by mass of an anti-ultraviolet aging agent.

[0011] As described above, the weather-resistant and fatigue-resistant offshore wind power cable structure features an armor layer with a double-layer reverse-wound composite steel wire structure. The inner layer is made of galvanized aluminum alloy steel wire, and the outer layer is made of aramid fiber reinforced steel wire. The winding pitch ratio of the two layers of steel wire is 12-16, and the winding directions of the inner and outer layers are opposite.

[0012] As described above, the structure of a weather-resistant and fatigue-resistant offshore wind power cable includes a conductor unit comprising, from the inside out, a conductor core, a conductor shielding layer, an insulation layer, and an insulation shielding layer. The conductor core is made of multiple strands of copper wire twisted together, and the gaps between the strands of the conductor core are filled with the water-blocking paste. The outer layer of the conductor core is covered with the water-blocking tape.

[0013] As described above, in a weather-resistant and fatigue-resistant offshore wind power cable structure, the insulation layer is a modified water-tree resistant material layer, and the insulation layer contains 2%-5% by mass of nano-silica filler and 1%-2% by mass of antioxidant. Both the conductor shielding layer and the insulating shielding layer are semi-conductive ethylene propylene rubber layers. Conductive carbon black and toughening agents are added to the semi-conductive ethylene propylene rubber layers. The particle size of the conductive carbon black is 20nm-50nm, and the toughening agent is an ethylene-octene copolymer with an addition amount of 5%-8%.

[0014] As described above, in a weather-resistant and fatigue-resistant offshore wind power cable structure, a bending reinforcement layer is added between the armored layer and the outer sheath. The bending reinforcement layer is an aramid fiber braided layer with a braiding density of ≥90%.

[0015] The weather-resistant and fatigue-resistant offshore wind power cable structure described above also includes an optoelectronic composite unit. The optoelectronic composite unit is disposed inside the armored layer, and the armored layer wraps around the optoelectronic composite unit. The optoelectronic composite unit includes a single-mode optical fiber and an optical fiber sheath wrapped around the outside of the optical fiber. The optical fiber sheath is a low-smoke, halogen-free, flame-retardant polyolefin sheath.

[0016] Secondly, the present invention also provides a method for manufacturing a weather-resistant and fatigue-resistant offshore wind power cable structure, comprising the following: Fabrication of conductor units: During the fabrication of conductor units, the inner conductor core of the conductor unit is filled with water-blocking paste, and the outer layer of the conductor core is covered with water-blocking tape; On the outside of the conductor unit, a metal sealing sleeve, a water-blocking buffer layer, an armor layer, and an outer sheath are sequentially arranged. The metal sealing sleeve is wrapped around the outside of the conductor unit by an extrusion molding process to achieve absolute radial water blocking. The water-blocking buffer layer includes a radial water-blocking strip and an elastic buffer layer arranged sequentially from the inside to the outside.

[0017] The beneficial effects of the present invention are as follows: In this invention, the conductor unit adopts a dual water-blocking structure of "water-blocking paste + water-blocking tape," effectively ensuring the water-blocking performance inside the conductor unit and preventing water intrusion. Furthermore, the water-blocking paste is placed on the inner side of the conductor unit, allowing it to withstand repeated bending caused by wind turbine swaying and ocean wave pulling. The outer metal sealing sheath of the conductor unit is a metal alloy sheath, which is extruded onto the outside of the conductor unit to achieve absolute radial water blocking. The metal alloy sheath possesses excellent sealing performance and mechanical strength, effectively preventing the intrusion of moisture, humidity, and external corrosive media, further enhancing the radial water blocking of the cable. The effect ensures the stable operation of the cable in harsh environments such as long-term seawater immersion. The radial water-blocking band and water-swellable rubber layer of the water-blocking buffer layer achieve efficient longitudinal water blocking. The water-blocking buffer layer and the metal sealing sheath form a full-section water blocking system. The radial water-blocking band in the water-blocking buffer layer can further enhance the radial water blocking capacity, while the elastic buffer layer can absorb and buffer the mechanical stress and vibration of the cable during laying and operation, reduce the damage to the internal structure caused by external impact, improve the fatigue resistance of the cable, effectively prevent moisture intrusion, inhibit water treeing aging of the insulation layer of the conductor unit, and extend the service life of the cable structure. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1 This is a cross-sectional view of a weather-resistant and fatigue-resistant offshore wind power cable structure according to one or more embodiments of the present invention.

[0020] The diagram exaggerates the spacing or dimensions between parts to show their positions; the diagram is for illustrative purposes only.

[0021] The components are: 1. Conductor core, 2. Conductor shielding layer, 3. Insulation layer, 4. Insulation shielding layer, 5. Metal sealing sheath, 6. Water-blocking buffer layer, 7. Optoelectronic composite unit, 8. Armored layer, and 9. Outer sheath. Detailed Implementation

[0022] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0023] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. As described in the background section, the poor water resistance of existing wind power cable structures leads to water trees forming in the conductor insulation layer due to moisture intrusion, resulting in a gradual deterioration of insulation performance. In order to solve the above technical problems, this invention proposes a weather-resistant and fatigue-resistant offshore wind power cable structure.

[0024] Example 1 In a typical embodiment of the present invention, reference is made to Figure 1As shown, a weather-resistant and fatigue-resistant offshore wind power cable structure includes, from the inside out, a conductor unit, a metal sealing sheath 5, a water-blocking buffer layer 6, an additional armor layer 8, and an outer sheath 9. The conductor unit contains a conductor core 1 filled with water-blocking paste, and the conductor core 1 is covered with a water-blocking tape, making the conductor core 1 a water-blocking composite structure. This effectively ensures the water-blocking performance inside the conductor unit, preventing water intrusion and affecting its service life. The metal sealing sheath 5 is a lead alloy sheath, which is extruded onto the outside of the conductor unit to achieve absolute radial water blocking. The radial water-blocking tape and water-swellable rubber layer of the water-blocking buffer layer 6 achieve efficient longitudinal water blocking. The water-blocking buffer layer 6 and the metal sealing sheath 5 form a full-section water-blocking system, effectively preventing moisture intrusion, inhibiting water treeing aging of the conductor unit's insulation layer, and extending the cable structure's service life. Furthermore, the additional armor layer 8 adopts a double-layer composite winding structure, effectively improving the cable structure's mechanical properties. The outer sheath 9 contains an environmentally friendly antifouling agent to prevent biological adhesion.

[0025] In this embodiment, the conductor unit includes a conductor core 1, a conductor shielding layer 2, an insulation layer 3, and an insulation shielding layer 4 arranged from the inside out. The conductor core 1 is made of multiple strands of copper wire twisted together. The twisted gaps of the conductor core 1 are filled with water-blocking paste, and the outer layer of the conductor core 1 is covered with water-blocking tape, forming a "paste + tape" double water-blocking structure to ensure the water-blocking performance of the conductor core 1 and prevent seawater from corroding the conductor core and affecting its service life. Specifically, the conductor core 1 uses a Class 5 soft conductor, the copper wire is made of oxygen-free copper, and the twist pitch ratio (the ratio of the twist pitch h to the outer diameter D of the stranded wire) is ≤16 to ensure the flexibility and conductivity stability of the conductor core 1.

[0026] It should be noted that the components of the water-blocking paste include base oil, water-absorbing and swelling resin, gelling agent, antioxidant, and dispersant. The base oil is selected from mineral oil or white oil, and the mass fractions of base oil, water-absorbing and swelling resin, gelling agent, antioxidant, and dispersant are 70%-81%, 10%-13%, 8%-12%, 0.5%-1.2%, and 1.5%-3.0%, respectively. The water-blocking paste always maintains an oily paste texture, which can adapt to repeated bending caused by fan swaying and wave pulling. The water-absorbing and swelling resin in the water-blocking paste can absorb water and seal gaps, and the water-blocking paste is insoluble in water, so it has good water-blocking performance.

[0027] In this embodiment, the base oil is selected as a mineral oil with a viscosity index greater than 120, which can maintain good fluidity in a temperature range of -40℃ to 120℃ to ensure uniform coating of the conductor core; the water-absorbing and swelling resin is a sodium polyacrylate grafted starch copolymer with a water absorption ratio ≥300g / g, and can quickly form a gel-like substance to block tiny gaps after absorbing water; the gelling agent adopts a compound system of organic bentonite and polyisobutylene, and the addition amount is 8%-12% of the total mass of the water-blocking paste, which can keep the water-blocking paste semi-solid at room temperature and produce plastic deformation when subjected to external pressure to fill the gap between the conductor core and the water-blocking strip; The antioxidant selected is a phenolic antioxidant, specifically a compound formulation of 2,6-di-tert-butyl-p-cresol (BHT) and phosphite antioxidants, with a total addition of 0.5%-1.2%. This effectively inhibits the oxidative aging of the base oil and extends the service life of the water-blocking paste. The dispersant selected is polyisobutylene succinimide, with an addition of 1.5%-3.0%. This promotes the uniform dispersion of the water-absorbing and swelling resin in the base oil, avoids agglomeration, and ensures the stability of the water-blocking performance.

[0028] The conductor unit can be 3, and the 3 conductor units are in contact with each other. The adjacent conductor units are tangential. The thickness of the insulation layer 3 is greater than the thickness of the insulation shielding layer 4. The thickness of the insulation layer 3 is 3-10 times the thickness of the insulation shielding layer 4. The thickness of the insulation shielding layer 4 is greater than the thickness of the conductor shielding layer 2. The thickness of the conductor shielding layer is greater than 0.8mm. The thickness of the insulation layer is designed according to different voltage levels to ensure the insulation capability of the conductor unit.

[0029] Insulation layer 3 in the conductor unit is a modified water-tree resistant material layer to further enhance the water-blocking performance of the conductor unit. Specifically, insulation layer 3 is a nano-modified water-tree resistant cross-linked polyethylene (XLPE) layer, with the thickness adjusted according to the voltage level. 2%-5% by mass of nano-silica filler and 1%-2% of antioxidant are added to the nano-modified water-tree resistant XLPE material to improve its water-tree resistant and aging resistance. The nano-silica filler can be uniformly dispersed in the XLPE matrix, forming physical cross-linking points, hindering the growth path of water trees, and simultaneously enhancing the mechanical strength and heat resistance of the insulation layer. The antioxidant can effectively capture free radicals generated during long-term operation, slowing down the oxidative degradation rate and ensuring that the cable maintains stable insulation performance in humid and high-temperature marine environments. After accelerated water tree (dendritic degradation phenomenon formed in cross-linked polyethylene (XLPE) cable insulation material under the combined action of high electric field and humid environment) aging test, the breakdown strength retention rate is ≥85%. Thus, the use of nano-modified water-tree resistant XLPE material improves the insulation performance of the conductor unit. In addition, both the conductor shielding layer 2 and the insulating shielding layer 4 are semi-conductive ethylene propylene rubber (EPR) layers. This material has excellent conductivity and mechanical flexibility, which can effectively eliminate interface effects and ensure uniform electric field distribution. Conductive carbon black and toughening agents are added to the semi-conductive EPR layer. The particle size of the conductive carbon black is 20-50nm, which ensures that the volume resistivity of the shielding layer is ≤100Ω·cm. The toughening agent is ethylene-octene copolymer, with an addition amount of 5%-8%, which significantly improves the tear resistance and flexural strength of the shielding layer, effectively adapting to the swaying and vibration environment of offshore wind power platforms. The conductor shielding layer 2 and the insulating shielding layer 4 adopt a co-extrusion molding process with the insulating layer during the molding process, resulting in a smooth interface without gaps, ensuring the compactness and reliability of the outer layer structure of the conductor unit.

[0030] Regarding the metal sealing sleeve 5, it is a lead alloy sleeve, which is extruded and wrapped around the outside of the insulating shielding layer 4 to achieve absolute radial water resistance. The lead alloy sleeve is made of a lead-tin-antimony alloy, with a lead mass fraction of 80%-92%, a tin mass fraction of 5%-13%, and an antimony mass fraction of 4%-7%. The tin content helps form a tin layer on the surface of the metal sealing sleeve, providing anti-oxidation and anti-corrosion effects, while the antimony provides flame retardancy. This ratio gives the sleeve both good ductility and mechanical strength, maintaining structural stability within a temperature range of -40℃ to 80℃. The lead alloy sleeve has a thickness of 1.2mm-2.0mm and is formed in one piece using a continuous extrusion process, ensuring no gaps between it and the insulating shielding layer, achieving complete radial sealing, and effectively preventing the intrusion of seawater, moisture, and corrosive media. Meanwhile, the lead alloy sheath undergoes passivation treatment to form a dense oxide film, further enhancing its resistance to seawater corrosion. In addition, the lead alloy sheath also possesses excellent fatigue resistance. Tests have shown that the metal sealing sheath shows no cracks or damage, and the overall structure exhibits good corrosion resistance, ensuring structural reliability under the long-term swaying and tidal influences of offshore wind power platforms.

[0031] In this embodiment, the water-blocking buffer layer 6 includes a radial water-blocking strip and an elastic buffer layer arranged sequentially from the inside to the outside. The radial water-blocking strip is an aluminum-plastic composite water-blocking strip with an overlap rate of ≥20%, which can effectively prevent water from penetrating radially along the cable and provide the first waterproof barrier for the internal structure of the cable. The elastic buffer layer is a water-swellable rubber layer, which can achieve longitudinal water blocking and absorb mechanical impact and vibration stress through its own deformation. The elastic buffer layer is made of neoprene rubber, which has strong deformation ability, reducing damage to the internal lead alloy sheath and cable core. At the same time, it can also fill the small depressions that may exist on the surface of the lead alloy sheath, effectively improving the tightness and stability of the overall structure.

[0032] Considering that existing armor layers mostly use a single galvanized steel wire, which has insufficient tensile and lateral pressure resistance and limited corrosion resistance in deep-sea high-pressure and highly corrosive environments, and the diameter of the galvanized steel wire is 4%-8% of the cable structure's outer diameter, this embodiment uses a double-layer reverse-wound composite steel wire structure for the armor layer. This significantly improves the cable's bending, torsional, and tensile fatigue resistance, adapting to the dynamic operating conditions required by floating wind power. The inner layer is galvanized aluminum alloy steel wire, and the outer layer is aramid fiber reinforced steel wire. The galvanized aluminum alloy steel wire has high strength and good corrosion resistance, and its surface galvanized aluminum alloy coating can effectively isolate seawater erosion. The outer aramid fiber reinforced steel wire utilizes the high strength and high modulus characteristics of aramid fibers to further enhance the torsional and tensile resistance of the armor layer. The selection of aramid fiber reinforced steel wire significantly improves the cable's... Its tensile and lateral pressure resistance meets the high-pressure and towing requirements of deep-sea laying (water depth > 60m); the elastic buffer layer can absorb mechanical shock and vibration, protecting the integrity of the internal structure; the double-layer steel wire has a winding pitch ratio of 12-16, and the inner and outer layers are wound in opposite directions. The double-layer reverse winding design creates mutual restraint tension between the steel wires, which can not only disperse the external pressure on the cable during laying and operation, but also effectively resist the repeated bending and torsional stress caused by factors such as sea waves and ocean currents, significantly improving the fatigue resistance of the cable and avoiding loosening or torsional deformation during laying and operation.

[0033] It needs to be explained that because the outer sheath of existing offshore wind power cables is susceptible to corrosion from marine organisms, affecting heat dissipation performance and structural integrity, the outer sheath 9 is a modified high-density polyethylene (HDPE) layer. The main component of the outer sheath 9 is high-density polyethylene, and it also contains 3%-5% by mass of an environmentally friendly copper ion antifouling agent. This antifouling agent uses nano-sized copper oxide particles as the active ingredient to form a continuous anti-biofouling protective layer on the surface of the outer sheath. It can resist corrosive environments such as high salt spray and seawater immersion, and can effectively inhibit the attachment and growth of marine organisms (such as barnacles, oysters, algae, etc.) on the cable surface, reducing the risk of increased cable weight, decreased heat dissipation performance, and mechanical damage caused by biofouling. It is suitable for the extreme environment of deep sea, making the outer sheath 9 a biofouling-resistant outer sheath. In addition, the outer sheath 9 also contains 2%-4% by mass of carbon black and 1%-3% by mass of an anti-UV aging agent. Carbon black can improve the weather resistance and thermal stability of the sheath, while the anti-UV aging agent can absorb ultraviolet energy and delay the photo-oxidative degradation of the material.

[0034] It should be noted that the thickness of the water-blocking buffer layer 6 is greater than the thickness of the metal sealing sheath 5, the thickness of the armor layer is greater than the thickness of the water-blocking buffer layer, and the thickness of the outer sheath 9 is greater than the thickness of the armor layer. This effectively ensures the thickness of the outer sheath 9 to protect the cable structure. Furthermore, the armor layer adopts a double-layer reverse-wound composite steel wire structure, thereby ensuring the mechanical strength of the armor layer 8 and improving the tensile and torsional performance of the overall structure.

[0035] The cable structure provided in this embodiment has a reasonable arrangement of each component. The multi-layer water-blocking component can effectively improve the water-blocking performance of the cable structure. The addition of the armor layer 8 and the metal sealing sheath 5 can effectively improve the fatigue resistance, weather corrosion resistance and mechanical strength of the overall structure, and ensure the tensile and torsional performance of the cable, making it suitable for the cable to run at sea.

[0036] Example 2 The difference between this embodiment and Embodiment 1 is that: For dynamic cables, a bending reinforcement layer is added between the armor layer 8 and the outer sheath 9; the bending reinforcement layer is an aramid fiber braided layer with a braiding density of ≥90%, which improves the cable's resistance to bending fatigue and ensures that the cable does not crack under bending radius ≤10D (D is the cable diameter) and millions of bending cycles (bending angle ±90°).

[0037] Example 3 The difference between this embodiment and Embodiment 1 or Embodiment 2 is that: The cable structure also includes an optoelectronic composite unit 7, which is located inside the armored layer. The armored layer encloses the optoelectronic composite unit, and the diameter of the optoelectronic composite unit is less than, greater than, or equal to the thickness of the armored layer. The optoelectronic composite unit 7 includes a single-mode optical fiber and an optical fiber sheath wrapped around the outside of the optical fiber. The optical fiber sheath is a low-smoke, halogen-free, flame-retardant polyolefin sheath, which has temperature resistance, corrosion resistance, and tensile strength. The single-mode optical fiber determines the fault location and accurately locates the fault by scattering light and measuring the time difference between the emitted and received signals. This achieves integrated power transmission, data communication, and status monitoring, reducing the laying cost and maintenance difficulty of deep-sea wind power projects.

[0038] Example 4 This embodiment discloses a method for manufacturing a weather-resistant and fatigue-resistant offshore wind power cable structure, including the following: Fabrication of conductor unit: During the fabrication of conductor unit, the inner conductor core 1 of conductor unit is filled with water-blocking paste, and the outer layer of conductor core is covered with water-blocking tape. Conductor shielding layer 2, insulation layer 3 and insulation shielding layer 4 are sequentially arranged in the circumferential direction of conductor core 1. On the outside of the conductor unit, a metal sealing sleeve 5, a water-blocking buffer layer 6, an armor layer 8 and an outer sleeve 9 are sequentially arranged. The metal sealing sleeve is wrapped around the outside of the conductor unit by an extrusion molding process to achieve absolute radial water blocking. The water-blocking buffer layer 6 includes a radial water-blocking strip and an elastic buffer layer arranged sequentially from the inside to the outside.

[0039] For details regarding the metal sealing sleeve 5, the water-blocking buffer layer 6, the added armor layer 8, and the outer sleeve 9, please refer to Example 1.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A weather-resistant and fatigue-resistant offshore wind power cable structure, characterized in that, The device includes, from the inside out, a conductor unit, a metal sealing sheath, a water-blocking buffer layer, an armor layer, and an outer sheath. The conductor unit has at least one set, and a conductor core is set inside the conductor unit. The conductor core is filled with water-blocking paste, and the conductor core is covered with a water-blocking tape, making the conductor core a water-blocking composite structure. The metal sealing sheath is a metal alloy sheath, which is wrapped around the outside of the conductor unit by an extrusion molding process to achieve absolute radial water blocking. The water-blocking buffer layer includes a radial water-blocking tape and an elastic buffer layer arranged from the inside out.

2. The weather-resistant and fatigue-resistant offshore wind power cable structure according to claim 1, characterized in that, The metal alloy sheath is made of lead-tin-antimony alloy, with a lead mass fraction of 80%-92%, a tin mass fraction of 5%-13%, and an antimony mass fraction of 3%-7%.

3. The weather-resistant and fatigue-resistant offshore wind power cable structure according to claim 1, characterized in that, The radial water-blocking strip is an aluminum-plastic composite water-blocking strip with an overlap rate of ≥20%; the elastic buffer layer is a water-swellable rubber layer, which can fill the tiny depressions on the surface of the lead alloy sheath.

4. The weather-resistant and fatigue-resistant offshore wind power cable structure according to claim 1, characterized in that, The water-blocking paste comprises base oil, water-absorbing and swelling resin, gelling agent, antioxidant, and dispersant, with the mass fractions of base oil, water-absorbing and swelling resin, gelling agent, antioxidant, and dispersant being 70%-81%, 10%-13%, 8%-12%, 0.5%-1.2%, and 1.5%-3.0%, respectively.

5. The weather-resistant and fatigue-resistant offshore wind power cable structure according to claim 1, characterized in that, The outer sheath is a modified polyethylene layer, comprising polyethylene, with 3%-5% by mass of an environmentally friendly copper ion antifouling agent added to the polyethylene, and 2%-4% by mass of carbon black and 1%-3% by mass of an anti-ultraviolet aging agent added to the polyethylene.

6. The weather-resistant and fatigue-resistant offshore wind power cable structure according to claim 1, characterized in that, The added armor layer adopts a double-layer reverse-wound composite steel wire structure. The inner layer is galvanized aluminum alloy steel wire, and the outer layer is aramid fiber reinforced steel wire. The winding pitch ratio of the double-layer steel wire is 12-16, and the winding directions of the inner and outer layers are opposite.

7. The weather-resistant and fatigue-resistant offshore wind power cable structure according to claim 1, characterized in that, The conductor unit includes, from the inside out, a conductor core, a conductor shielding layer, an insulation layer, and an insulation shielding layer. The conductor core is made of multiple strands of copper wire twisted together. The gaps between the strands of the conductor core are filled with the water-blocking paste. The outer layer of the conductor core is covered with the water-blocking tape.

8. The weather-resistant and fatigue-resistant offshore wind power cable structure according to claim 7, characterized in that, The insulating layer is a modified water-resistant material layer, with 2%-5% by mass of nano-silica filler and 1%-2% by mass of antioxidant added to the insulating layer; Both the conductor shielding layer and the insulating shielding layer are semi-conductive ethylene propylene rubber layers. Conductive carbon black and toughening agents are added to the semi-conductive ethylene propylene rubber layers. The particle size of the conductive carbon black is 20-50 nm, and the toughening agent is an ethylene-octene copolymer with an addition amount of 5%-8%.

9. The weather-resistant and fatigue-resistant offshore wind power cable structure according to claim 1, characterized in that, A bending reinforcement layer is added between the armor layer and the outer sheath. The bending reinforcement layer is an aramid fiber braided layer with a braiding density of ≥90%.

10. The weather-resistant and fatigue-resistant offshore wind power cable structure according to claim 1, characterized in that, It also includes an optoelectronic composite unit, which is located inside the armored layer. The armored layer surrounds the optoelectronic composite unit. The optoelectronic composite unit includes a single-mode optical fiber and an optical fiber sheath wrapped around the outside of the optical fiber. The optical fiber sheath is a low-smoke, halogen-free, flame-retardant polyolefin sheath.

11. A method for manufacturing a weather-resistant and fatigue-resistant offshore wind power cable structure according to any one of claims 1-10, characterized in that, Includes the following: Fabrication of conductor units: During the fabrication of conductor units, the inner conductor core of the conductor unit is filled with water-blocking paste, and the outer layer of the conductor core is covered with water-blocking tape; On the outside of the conductor unit, a metal sealing sleeve, a water-blocking buffer layer, an armor layer, and an outer sheath are sequentially arranged. The metal sealing sleeve is wrapped around the outside of the conductor unit by an extrusion molding process to achieve absolute radial water blocking. The water-blocking buffer layer includes a radial water-blocking strip and an elastic buffer layer arranged sequentially from the inside to the outside.

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