A kind of 10kV power cable for coastal area with water resistance salt spray corrosion resistance

Abstract

The application discloses a kind of water-blocking salt-fog-resistant anticorrosion 10kV power cable for coastal areas, including three single-core insulated wire cores, center composite framework and multilayer outer sheath.The cross section of center composite framework is triangular, and circular arc transition grooves are formed at three vertices respectively, and three single-core insulated wire cores are correspondingly embedded in the grooves.Center composite framework includes framework matrix, center reinforcing core and multilayer composite coating, and a plurality of through holes are provided in the framework matrix, and the multilayer composite coating is sequentially plasma activated layer, moisture-cured polyurethane hot melt adhesive primer layer and asphalt affinity transition layer from inside to outside.The through holes and annular space gaps are filled with modified asphalt casting body.The application forms an interface structure of physical combination, chemical bonding and chain segment intertangling combination between the framework matrix and the modified asphalt casting body through the multilayer composite coating, to improve the interface bonding strength and durability, thereby improving the structural stability and radial moisture-proof performance of the cable.

Description

Technical Field

[0001] This application relates to the field of cable technology, and in particular to a 10kV power cable for use in coastal areas that is water-resistant, salt spray resistant, and corrosion-resistant. Background Technology

[0002] The rapid development of new energy power generation bases, offshore wind farms, and port power distribution networks in coastal areas has led to an increase in the laying of 10kV medium-voltage power cables in environments with salt spray, high humidity, and strong ultraviolet radiation. During the service life of these cables, failures are usually not caused by a single factor, but are caused by the combined effects of salt spray corrosion, moisture penetration, interface peeling, and structural fatigue. These factors are interrelated and cumulative, seriously threatening the safe operation of the power grid.

[0003] In a three-core cable structure, the central skeleton is used to fix the relative positions of the cores and maintain the stability of the cable's geometry. The quality of the interface bonding between the central skeleton and the filler material directly determines the cable's longitudinal water-blocking performance. Currently, the central skeleton is commonly made of high-density polyethylene or glass fiber reinforced nylon through injection molding. These two types of materials have insufficient interfacial bonding with the petroleum asphalt used for cable filler. The thermal cycling effect caused by the diurnal temperature variation in coastal areas, coupled with the continuous erosion of the interface by the salt spray environment, makes it extremely easy for micro-cracks to initiate at the interface between the skeleton and the asphalt, which then expand into longitudinally penetrating water seepage channels. Once moisture seeps into the cable through these channels, the electrical performance of the insulation layer deteriorates, and in severe cases, it can lead to breakdown discharge.

[0004] In addition, conventional polymer skeleton materials lack active groups on their surface that can chemically react with asphalt, and the interfacial bonding is mainly physical contact. Under thermal cycling stress and salt spray erosion, it is difficult to maintain long-term stability, and the interfacial debonding and the formation of water seepage channels are difficult to avoid at the root.

[0005] Therefore, the long-term operational reliability of existing 10kV three-phase single-core power cables in harsh coastal environments is still significantly insufficient and urgently needs improvement. Summary of the Invention

[0006] This application addresses the technical problem of existing 10kV three-phase single-core power cables exhibiting reduced insulation performance in coastal salt spray, high humidity, and thermal cycling environments due to insufficient interfacial bonding strength between the skeleton and asphalt filler material, leading to microcracks and longitudinal water seepage channels. The application provides a water-blocking, salt spray-resistant, and corrosion-resistant 10kV power cable for coastal areas. This cable features a central composite skeleton with a triangular cross-section and a circular arc transition groove. The skeleton substrate surface is sequentially formed with a plasma-activated layer, a moisture-curing polyurethane hot melt adhesive primer layer, and an asphalt affinity transition layer. Modified asphalt castings are filled into the internal through-holes and annular spaces of the skeleton. This multi-layered composite coating sequentially forms physical interlocking, chemical bonding, and inter-diffusion, swelling, and physical entanglement between the skeleton and asphalt, achieving multi-layered interfacial bonding to improve interfacial bonding strength and durability, thereby enhancing the cable's structural stability and radial moisture resistance. The technical solution provided in this application is as follows: This application provides a 10kV power cable for use in coastal areas that is water-resistant, salt spray-resistant, and corrosion-resistant, comprising: The three single-core insulated wire cores, each of which, from the inside out, includes a conductor, a conductor shielding layer, an insulation layer, an insulation shielding layer, a phase-separated metal shielding layer, and a phase-separated water-blocking and corrosion-resistant inner protective layer; The central composite skeleton has a triangular cross-section, with arc transition grooves formed at its three vertices, and the three single-core insulated wire cores are correspondingly embedded in the arc transition grooves. The central composite skeleton includes a skeleton matrix, a central reinforcing core embedded in the center of the skeleton matrix and extending along the axial direction, and a multilayer composite coating disposed on the outer surface of the skeleton matrix. The skeleton matrix has multiple through-holes along the axial direction inside. The multi-layer composite coating comprises, from the inside out, a plasma activation layer, a moisture-curing polyurethane hot melt adhesive primer layer, and an asphalt affinity transition layer. The through-hole and the annular space between the three single-core insulated wire cores and the central composite skeleton are filled with modified asphalt castings; the central composite skeleton improves structural stability and waterproof reliability. And the multi-layer outer sheath that sequentially covers the three single-core insulated wires and the outer side of the central composite skeleton after the cable is formed, from the inside out.

[0007] In some specific embodiments, the skeleton matrix is ​​made of basalt fiber reinforced polybutylene terephthalate, wherein the mass fraction of basalt fiber is 25%~35%; The central reinforcing core is made of galvanized aluminum-magnesium alloy steel wire.

[0008] In some specific embodiments, the bitumen affinity transition layer comprises the following components in parts by weight: 10-15 parts of star-shaped styrene-ethylene-butene-styrene block copolymer, with a weight-average molecular weight of 200,000-300,000 and a styrene segment mass fraction of 32%-35%; 8-12 parts of random polypropylene, with a weight-average molecular weight of 10,000-30,000; 75-82 parts of petroleum asphalt; 2-3 parts of hydrophobic fumed silica, with a specific surface area of ​​100-160 m2 / g and a particle size of 12-20 nm; The thickness of the asphalt affinity transition layer is 0.5~1.0 mm.

[0009] In some specific embodiments, the modified asphalt casting body comprises the following components in parts by weight: 60-70 parts of petroleum asphalt; 10-20 parts of nano-halostone tube-supported polyether-type polyurethane prepolymer composite modified powder; 8-12 parts of ethylene-ethyl acrylate copolymer; 3-5 parts of random polypropylene; Citric acid 0.2~0.4 parts; Antioxidant 0.4~0.6 parts; 3-4 parts of hydrophobic fumed silica; 1.5 to 2.5 parts organic bentonite; Benzotriazole 1.0~1.5 parts; 5-10 parts of water-absorbing and swelling polyurethane microspheres; 1-2 parts of dimethyl silicone oil.

[0010] In some specific embodiments, the insulating layer is made of modified polypropylene-based insulating material, which comprises the following components in parts by weight: 70-80 parts of homopolymer polypropylene; 8-12 parts of ethylene-butyl acrylate copolymer; 5-10 parts of silane-grafted polypropylene; 4-6 parts of fluorosilane-modified hexagonal boron nitride; Nucleating agent 0.1~0.2 parts; Antioxidant 0.2~0.4 parts; Lubricant 0.1~0.2 parts; The silane-grafted polypropylene is formed by melt grafting vinyltrimethoxysilane onto polypropylene under the initiation of dicumyl peroxide, with a grafting rate of 1.5-2.5%; the fluorosilane-modified hexagonal boron nitride is surface-treated with tridecafluorooctyltriethoxysilane, with a particle size of 100-500 nm and a sheet thickness of 10-50 nm.

[0011] In some specific embodiments, the phase-separated metal shielding layer is a tin-plated copper strip overlapping and wrapping structure; the outer surface of the tin-plated copper strip is coated with a graphene oxide / γ-aminopropyltriethoxysilane composite coating; and the inner surface of the tin-plated copper strip is coated with a semi-conductive adhesive.

[0012] In some specific embodiments, the multi-layer outer sheath includes, from the inside out, a cable wrapping layer, an elastic moisture-absorbing buffer strip, a radial moisture-proof layer, an inner lining layer, a braided reinforcement layer, and an outer sheath.

[0013] In some specific embodiments, both the phase-separated water-blocking and corrosion-resistant inner protective layer and the inner lining layer are extruded from a water-blocking and corrosion-resistant ethylene propylene rubber composite material, which comprises the following components by weight: 60-75 parts of EPDM raw rubber; 15-20 parts of linear low-density polyethylene; 10-15 parts of ethylene-vinyl acetate copolymer; 3-5 parts of hydrogenated styrene-butadiene-styrene block copolymer; 8-12 parts of naphthenic oil; Peroxide crosslinking agent 1.5~2.0 parts; Antioxidant 2.5~3.5 parts; 20-30 parts of reinforcing filler; 1.0 to 1.5 parts of titanate coupling agent; 2.0~3.0 parts of lubricant.

[0014] In some specific embodiments, the elastic moisture-absorbing buffer strip is disposed on the outside of the cable wrapping layer in a spiral winding manner, and the elastic moisture-absorbing buffer strip includes: Radial elastic buffer layer: Closed-cell EPDM rubber chemical foam, foaming ratio 2.5~3.5 times, density 0.25~0.35g / cm3, closed-cell rate ≥80%, Shore A hardness 25~40; Moisture-absorbing and shaping layer: Moisture-absorbing filler that fills the cavity inside the radial elastic buffer layer, with a filling volume accounting for 45-55% of the cavity volume inside the radial elastic buffer layer; Selective moisture-permeable layer: Expanded polytetrafluoroethylene waterproof and breathable membrane coated on the outer surface of the radial elastic buffer layer by hot-melt composite method, with a thickness of 0.08~0.12mm and an average pore size of 0.2~0.5μm.

[0015] In some specific embodiments, the radial moisture barrier layer includes an aluminum-plastic composite tape longitudinal wrapping layer and a polyethylene layer extruded on the outside of the aluminum-plastic composite tape longitudinal wrapping layer; the woven reinforcement layer is made of a mixture of aramid fiber and ultra-high molecular weight polyethylene fiber.

[0016] By adopting the above technical solution, the 10kV water-resistant, salt spray-resistant, and corrosion-resistant power cable for coastal areas provided in this application has the following beneficial effects: This application forms a multi-layered composite coating by sequentially depositing a plasma activation layer, a moisture-curing polyurethane hot melt adhesive primer layer, and an asphalt affinity transition layer on the surface of a central composite skeleton substrate. The plasma activation layer introduces polar groups and increases surface roughness on the skeleton substrate surface, providing a bonding interface for the subsequent coating adhesion. The isocyanate groups in the moisture-curing polyurethane hot melt adhesive primer layer react with the hydroxyl groups on the activation layer surface to form urethane bonds, creating a chemical bond between the primer layer and the skeleton substrate. Simultaneously, hydrogen bonds and chemical cross-links are formed between the isocyanate groups and some groups in the asphalt affinity transition layer. Molecular chains interpenetrate and entangle between the asphalt affinity transition layer and the modified asphalt casting. Through the multi-layered composite coating, a combined physical bond, chemical bond, and segment entanglement interface structure is formed between the skeleton and the asphalt, which improves the interfacial bonding strength and long-term durability between the central composite skeleton and the asphalt, inhibits the initiation and propagation of interfacial microcracks under thermal cycling stress and salt spray erosion, thereby preventing the formation of longitudinal water seepage channels. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the cross-sectional structure of a 10kV power cable for use in coastal areas, which is a water-blocking, salt spray-resistant, and corrosion-resistant cable provided in this application embodiment.

[0019] The following is supplementary explanation of the attached figures: 1-Conductor; 2-Conductor shielding layer; 3-Insulation layer; 4-Insulation shielding layer; 5-Phase-separating metal shielding layer; 6-Phase-separating water-blocking and corrosion-resistant inner protective layer; 7-Central composite skeleton; 8-Cable wrapping layer; 9-Elastic moisture-absorbing buffer strip; 10-Radial moisture-proof layer; 11-Inner lining layer; 12-Braided reinforcement layer; 13-Outer sheath. Detailed Implementation

[0020] 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.

[0021] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of this application. In the description of this application, it should be understood that the terms "upper," "lower," "top," "bottom," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application. 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 indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Moreover, the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein.

[0022] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are included. For example, a specified range from “1 to 10” should be considered to include any and all subranges between the minimum value 1 and the maximum value 10. Exemplary subranges of the range 1 to 10 include, but are not limited to, 1 to 6.1, 3.5 to 7.8, 5.5 to 10, etc.

[0023] like Figure 1 As shown in the figure, this application provides a 10kV power cable for coastal areas that is water-resistant, salt spray resistant and corrosion resistant, including three single-core insulated wires, a central composite frame 7, and a multi-layer outer sheath that is sequentially wrapped around the three single-core insulated wires and the central composite frame 7 from the inside out.

[0024] Each single-core insulated wire core includes, from the inside out, conductor 1, conductor shielding layer 2, insulation layer 3, insulation shielding layer 4, phase-separated metal shielding layer 5, and phase-separated water-blocking and corrosion-resistant inner protective layer 6.

[0025] Conductor 1 is made of tin-plated annealed copper conductor 1 or 8000 series aluminum alloy conductor 1, and is composed of multiple single wires stranded in layers, with a stranding compaction factor of not less than 0.96. For tin-plated annealed copper conductor 1, the thickness of the tin plating layer on the surface of each single wire is 1~3μm, and the tin purity is not less than 99.9%. Conductor shielding layer 2 is extruded from semi-conductive shielding material, with a thickness of 0.7~0.9mm. Insulation layer 3 is modified polypropylene-based insulation material. Insulation shielding layer 4 is a peelable semi-conductive layer with a thickness of 0.5~0.8mm. Phase-separating metal shielding layer 5 is a tin-plated copper strip overlapping and wrapping structure. Phase-separating water-blocking and corrosion-resistant inner protective layer 6 is extruded from water-blocking and corrosion-resistant ethylene propylene rubber composite material.

[0026] The central composite skeleton 7 has a triangular cross-section with arc-shaped transition grooves at its three vertices. Three single-core insulated wires are correspondingly embedded within these grooves. The radius of the arc-shaped transition grooves matches the outer diameter of the single-core insulated wires, ensuring stable positioning of the wires after embedding and preventing relative displacement during cabling. In this embodiment, the central composite skeleton 7 has an equilateral triangular cross-section with side lengths of 35-55 mm, and the radii R of the three arc-shaped transition grooves are 12-18 mm, matching the outer diameter of the phase-separated water-blocking and corrosion-resistant inner sheath 6.

[0027] The central composite skeleton 7 includes a skeleton matrix, a central reinforcing core embedded in the center of the skeleton matrix and extending along the axial direction, and a multi-layer composite coating disposed on the outer surface of the skeleton matrix.

[0028] The skeleton matrix has multiple through-holes along the axial direction. The through-holes and the annular gaps between the three single-core insulated wire cores and the central composite skeleton 7 are all filled with modified asphalt castings.

[0029] Traditional three-core stranded cables suffer from defects such as loose strands, inter-core compression, longitudinal water seepage, and long-term collapse due to loose filling (e.g., loose filling with water-blocking yarn / PP rope). The central composite skeleton 7 addresses these issues with its rigid constraint formed by the three vertices of a triangular skeleton fitted with grooves that improve cable roundness and prevent inter-core slippage and electric field distortion. Modified asphalt is injected into the perforated skeleton to form a continuous hydrophobic barrier. The central reinforcing core bears the longitudinal tensile force, while the skeleton matrix (glass fiber reinforced PBT / basalt fiber) provides radial support, evenly distributing bending and compressive loads and preventing direct shearing of the insulation layer, thus improving flattening resistance. This significantly enhances structural stability and waterproof reliability in coastal conditions.

[0030] The multi-layer composite coating consists of, from the inside out, a plasma-activated layer, a moisture-curing polyurethane hot melt adhesive primer layer, and an asphalt affinity transition layer.

[0031] The plasma-activated layer is formed by treating the outer surface of the matrix substrate with low-temperature air plasma at a pressure of 0.3–0.5 mbar, a power of 200–300 W, and a duration of 60–120 s. After plasma treatment, polar groups such as hydroxyl and carboxyl groups are introduced into the surface of the matrix substrate, increasing the surface energy from 30–35 mN / m to 50–60 mN / m. Simultaneously, the surface micro-roughness increases, providing a bonding interface for the subsequent coating adhesion.

[0032] A moisture-curing polyurethane hot melt adhesive primer layer is applied to the surface of the plasma-activated layer. This primer layer is a moisture-curing polyurethane hot melt adhesive with an isocyanate (NCO) content of 1.5%–2.5%. After application, the primer layer cures under the influence of moisture. The isocyanate groups react with the hydroxyl groups on the surface of the plasma-activated layer to form urethane bonds, creating a chemical bond between the primer layer and the matrix. Furthermore, the isocyanate groups form hydrogen bonds and chemical crosslinks with some groups in the bitumen affinity transition layer, creating a chemical bridge between the matrix and the bitumen.

[0033] An asphalt affinity transition layer is applied to the surface of a moisture-curing polyurethane hot melt adhesive primer layer, with a thickness of 0.5~1.0 mm. The surface energy of the asphalt affinity transition layer is close to that of petroleum asphalt. Its styrene-ethylene-butene-styrene block copolymer (SEBS) segments and atactic polypropylene (aPP) segments swell during the subsequent high-temperature casting of the modified asphalt mixture, forming an intertwined structure with the cast asphalt. Understandably, the asphalt affinity transition layer can form a more stable bond with other layers through pre-curing, application of crosslinking agents, etc., without specific limitations on the specific method.

[0034] Thus, the bonding interface provided by plasma treatment, the chemical bonding provided by the moisture-curing polyurethane hot melt adhesive primer layer, and the entanglement of chain segments provided by the asphalt affinity transition layer together form the interfacial bonding of the composite coating between the skeleton matrix and the modified asphalt casting.

[0035] During cable making, the central composite skeleton 7, which contains three single-core insulated wires, is stranded according to a predetermined stranding pitch so that each wire is evenly distributed along the central composite skeleton 7 to maintain the symmetry and stability of the cable's geometric structure. Then, multiple outer sheaths are sequentially installed.

[0036] In some specific embodiments, the skeleton matrix is ​​made of basalt fiber reinforced polybutylene terephthalate (PBT), wherein the mass fraction of basalt fiber is 25% to 35%. PBT has low moisture absorption, resistance to salt spray corrosion, and good dimensional stability; its aging rate in high-humidity, high-salt coastal environments is lower than that of polyamide materials. Basalt fiber exhibits superior chemical corrosion resistance compared to traditional glass fiber, and its high elastic modulus effectively improves the rigidity, creep resistance, and heat deformation resistance of the skeleton. Controlling the mass fraction of basalt fiber at 25% to 35% ensures both injection molding flowability and meets mechanical support performance requirements.

[0037] The central reinforcing core is made of zinc-aluminum-magnesium alloy steel wire. Its Zn-Al-Mg ternary coating exhibits superior corrosion resistance compared to traditional pure zinc coatings in coastal high-salt spray environments through the synergistic effect of the formation of a dense oxide film, microstructure refinement, and sacrificial anode protection, effectively delaying the corrosion thinning and strength reduction of the steel wire.

[0038] Preferably, the central reinforcing core uses 1×7 structure galvanized-aluminum-magnesium alloy steel wire, with a coating composition of Zn-5%Al-0.5%Mg, a coating thickness ≥80μm, a single wire diameter of 0.6~0.9mm, and a stranded outer diameter of 1.8~2.7mm. This structure has high tensile strength and a certain degree of flexibility, providing anti-flattening support for the skeleton while meeting the process requirements for cable bending and laying.

[0039] In some specific embodiments, the bitumen affinity transition layer comprises the following components in parts by weight: The star-shaped styrene-ethylene-butene-styrene block copolymer comprises 10-15 parts, with a weight-average molecular weight of 200,000-300,000 and a styrene segment mass fraction of 32%-35%. In this star-shaped styrene-ethylene-butene-styrene block copolymer, the styrene segments provide mechanical strength, while the ethylene-butene segments provide flexibility. Its hydrocarbon structure exhibits good compatibility with asphalt components and can form an interfacial fusion with the modified asphalt casting.

[0040] Atactic polypropylene (8-12 parts) with a weight-average molecular weight of 10,000-30,000. Atactic polypropylene is a low molecular weight, low crystallinity olefin polymer with good compatibility with asphalt components. In blending systems, this component can reduce melt viscosity, improve processing fluidity, and regulate the softening point and wetting and spreading properties of the asphalt affinity transition layer.

[0041] 75-82 parts of petroleum asphalt serve as the matrix phase. It belongs to the same petroleum hydrocarbon material as the subsequently poured asphalt, and their polarities are similar, which helps to reduce interfacial tension.

[0042] Two to three parts of hydrophobic fumed silica, with a specific surface area of ​​100 to 160 m² / g and a particle size of 12 to 20 nm, are added. The nanoscale particle size and high specific surface area of ​​fumed silica enable it to form a three-dimensional network structure in the blend system, thereby improving the thixotropy of the system, preventing sagging during casting, and enhancing the structural stability of the asphalt affinity transition layer.

[0043] The above components, when blended, form a hydrocarbon-rubber blend system. This blend system exhibits low interfacial tension with the subsequently poured modified asphalt casting, demonstrating good compatibility between the two.

[0044] In some specific embodiments, the modified asphalt casting body comprises the following components in parts by weight: 60-70 parts of petroleum asphalt, straight-run asphalt can be used, with a softening point of 105℃-115℃, a penetration of 50dmm-80dmm, and a density of 1.0g / cm³. 3 ~1.05g / cm 3 .

[0045] 10-20 parts of a modified powder (HNTs-PU) of nano-haloysite tube-supported polyether-type polyurethane prepolymer. The halloysite tubes are natural aluminosilicate nanotubes with an outer diameter of 50 nm-100 nm, an inner diameter of 15 nm-30 nm, a length of 500 nm-1500 nm, and a specific surface area of ​​60 m². 2 / g~80m 2 / g, thermal decomposition temperature ≥600℃. The NCO content of the polyether-type polyurethane prepolymer is 2%~4%, the viscosity at 25℃ is 2000mPa·s~5000mPa·s, and the density is 1.08g / cm³. 3 ~1.12g / cm 3 Halloysite tubes are prepared by reacting polytetrahydrofuran ether diol with toluene diisocyanate or diphenylmethane diisocyanate. Halloysite tubes are then loaded with polyether-type polyurethane prepolymers via a vacuum impregnation process. The vacuum level is ≤-0.09 MPa, the temperature is 60℃~80℃, the time is 2h~4h, and the loading rate is controlled at 25%~40%. After loading, the tubes are surface-treated with γ-aminopropyltriethoxysilane, which forms Si-O-Al and Si-O-Si covalent bonds with the hydroxyl groups on the halloysite tube surface. This results in the final product being aggregates with a particle size of 5μm~30μm and a specific surface area of ​​30m². 2 / g~50m 2 / g. The tubular structure of halloysite tubes forms a three-dimensional network reinforcement in the asphalt matrix; after silane treatment, the interfacial interaction between the amino groups on its surface and the polar components in the asphalt is enhanced, which is beneficial to improving the interfacial bond strength.

[0046] 8-12 parts of ethylene-ethyl acrylate copolymer, wherein the ethyl acrylate content is 20%-25% and the melt index is 5g / 10min-10g / 10min, can be used as a polar elastomer modifier to improve the low-temperature toughness and crack resistance of asphalt, and form hydrogen bonds or coordination with the polar groups introduced by citralic acid to improve the compatibility and stability of the asphalt system.

[0047] 3-5 parts of atactic polypropylene, with a softening point of 150℃-160℃, are used as a tackifying resin to adjust the softening point and high-temperature anti-flow properties of asphalt.

[0048] When 0.2-0.4 parts of citralic acid are melt-dispersed at a mixing temperature of 170℃-180℃, the double bonds in its molecule can undergo physical blending and polar interaction with polycyclic aromatic hydrocarbons and unsaturated components in petroleum asphalt, introducing polar carboxyl groups in situ. The two carboxyl groups form hydrogen bonds or coordination with polar components such as ethylene-ethyl acrylate copolymers, improving the compatibility between asphalt and polymers. At the same time, the carboxyl groups can neutralize the basic nitrogen compounds in asphalt, improving the thermal stability and anti-aging properties of asphalt.

[0049] Antioxidant 0.4~0.6 parts are used to inhibit the thermo-oxidative degradation of asphalt during high-temperature mixing and long-term use. The antioxidant can be made by compounding pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) and tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) in a mass ratio of 1:1.

[0050] Add 3-4 parts of hydrophobic fumed silica to form a three-dimensional network structure in the system, improve thixotropy and prevent sagging during casting.

[0051] 1.5 to 2.5 parts of organic bentonite, modified with hexadecyltrimethylammonium bromide, with an interlayer spacing ≥3.0 nm and a particle size ≤10 μm, form a lamellar dispersion structure in the asphalt, further improving the thixotropic properties and anti-flow properties of the system, and preventing the modified asphalt from being lost from the gaps in the skeleton during high-temperature casting.

[0052] 1.0 to 1.5 parts of benzotriazole, as a metal corrosion inhibitor, is beneficial for the corrosion inhibition of metal shielding layers and steel wire surfaces.

[0053] Five to ten parts of water-absorbing and expanding polyurethane microspheres, with a particle size of 1 mm to 3 mm and a water absorption ratio of 8 to 15 times, expand in volume upon contact with water, which can seal the micro-gap at the interface between the skeleton and the asphalt, forming a dynamic self-healing water barrier.

[0054] 1-2 parts of dimethyl silicone oil, which is polydimethylsiloxane, acts as a surfactant to reduce the surface tension of the asphalt casting, promote the filling and flow of asphalt in the through-holes and annular spaces during grouting, and improve the filling density.

[0055] The above components are melt-blended to form a homogeneous modified asphalt system. Specifically, the ethylene-ethyl acrylate copolymer and atactic polypropylene synergistically improve the compatibility between the asphalt and the skeleton coating; the tubular structure of the nano-halostone tube-supported polyether-type polyurethane prepolymer composite modified powder forms a three-dimensional reinforcing network in the asphalt and mechanically interlocks with the asphalt affinity transition layer on the skeleton matrix surface; citralic acid promotes interfacial compatibility between the asphalt and the ethylene-ethyl acrylate copolymer; organobentonite and hydrophobic fumed silica jointly improve thixotropy and anti-flow properties; dimethyl silicone oil reduces surface tension to promote injection filling; benzotriazole protects the metal shielding layer and steel wire; and water-absorbing and swelling microspheres swell upon contact with water to seal micro-gaps. The synergistic effect of these components gives the modified asphalt casting high filling density, interfacial bonding strength, salt spray corrosion resistance, and dynamic self-healing water-blocking capability.

[0056] In some specific embodiments, the insulating layer 3 is made of modified polypropylene-based insulating material, which comprises the following components in parts by weight: 70-80 parts of homopolymer polypropylene with isotacticity ≥96% and melt flow rate of 0.3g / 10min~0.5g / 10min (230℃, 2.16kg). High isotacticity polypropylene has high crystallinity, which is beneficial to improving the electrical insulation performance and mechanical strength of insulation layer 3, meeting the requirements of medium voltage cable for insulation dielectric breakdown field strength.

[0057] 8-12 parts of ethylene-butyl acrylate copolymer are used as toughening modifiers. The butyl acrylate segments form a partially compatible structure with the polypropylene matrix and can be uniformly dispersed in the polypropylene matrix. This effectively reduces the brittle transition temperature of polypropylene, improves the impact resistance of insulation layer 3 under low-temperature laying conditions, and maintains good electrical insulation.

[0058] Five to ten parts of silane-grafted polypropylene were prepared by melt grafting vinyltrimethoxysilane onto polypropylene under the initiation of dicumyl peroxide, with a grafting rate of 1.5% to 2.5%. The trimethoxysilane groups in the silane-grafted polypropylene undergo hydrolysis and condensation reactions during the warm water bath treatment after extrusion, forming a Si-O-Si crosslinked network, which is beneficial to improving the heat distortion temperature and long-term thermal stability of the insulating layer 3.

[0059] Four to six parts of fluorosilane-modified hexagonal boron nitride (BON) were obtained by surface treatment of BON raw powder with tridecafluorooctyltriethoxysilane. The particle size was 100–500 nm, and the layer thickness was 10–50 nm. BON has a layered structure, high thermal conductivity, and good electrical insulation. After surface treatment, its surface energy is reduced, improving its dispersibility in the polypropylene matrix and enhancing the compatibility between the filler and the polymer interface. In the insulating layer 3, fluorosilane-modified BON can form thermally conductive channels, promoting the conduction of heat from conductor 1 to the outside of the insulating layer 3 and reducing local temperature rise. Its layered structure also hinders the propagation path of electrical trees, thus improving the partial discharge resistance of the insulating layer 3.

[0060] The nucleating agent, N,N'-dicyclohexyl terephthalamide, is 0.1 to 0.2 parts. It can refine the size of polypropylene spherulites to 5 μm to 10 μm, increase the grain boundary density, and improve the breakdown field strength and withstand voltage performance of the insulating layer 3.

[0061] Antioxidant 0.2-0.4 parts, which can be prepared by compounding pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] with tris[2,4-di-tert-butylphenyl] phosphite in a mass ratio of 1:1. It is beneficial to inhibit the thermo-oxidative aging of polypropylene during high-temperature extrusion and long-term operation.

[0062] The lubricant, consisting of 0.1 to 0.2 parts of zinc stearate, reduces friction between the melt and the screw and die wall during extrusion, thereby improving processing fluidity.

[0063] After melt extrusion, the above components are extruded and the resulting insulated wire core is hydrolyzed and crosslinked in a water bath at 80℃~90℃ for 4h~6h. This allows for the complete hydrolysis and condensation of the methoxy groups in the silane-grafted polypropylene, forming a dense Si-O-Si organic-inorganic hybrid crosslinked network. In this system, the ethylene-butyl acrylate copolymer improves the low-temperature toughness of polypropylene and forms partial compatibility with the matrix; the three-dimensional crosslinked network formed after the hydrolysis of silane-grafted polypropylene is beneficial for improving thermal stability; fluorosilane-modified hexagonal boron nitride constructs thermally conductive channels, and its low surface energy characteristics facilitate uniform dispersion of the filler; the nucleating agent refines the spherulite size to improve the breakdown field strength. The synergistic effect of the components gives insulation layer 3 good electrical insulation performance, thermal conductivity, mechanical toughness, and long-term thermal aging stability, meeting the operational requirements of 10kV medium-voltage cables in harsh coastal environments. Understandably, the reaction can be ensured and promoted by adding catalysts (such as organotin catalysts), which are not specifically limited here.

[0064] In some specific embodiments, the phase-separated metal shielding layer 5 is a tin-plated copper strip overlapping and wrapping structure; the outer surface of the tin-plated copper strip is coated with a graphene oxide / γ-aminopropyltriethoxysilane composite coating, in which the sheet structure of graphene oxide forms a dense physical barrier layer on the surface of the copper strip, which can effectively extend the Cl - The diffusion path of corrosive ions reduces the electrochemical corrosion rate of the copper strip; γ-aminopropyltriethoxysilane hydrolyzes and forms chemical bonds with the copper strip surface, improving coating adhesion and interface durability. The inner surface of the tin-plated copper strip is coated with a semi-conductive adhesive, which is based on acrylate and forms an ohmic contact with the insulating shielding layer 4, ensuring uniform electric field distribution and eliminating the risk of interface air gap discharge.

[0065] In some specific embodiments, the multi-layered outer sheath, from the inside out, includes a cabling wrapping layer 8, an elastic moisture-absorbing buffer strip 9, a radial moisture-proof layer 10, an inner lining layer 11, a braided reinforcement layer 12, and an outer sheath 13. The cabling wrapping layer 8 covers the outside of the three single-core insulated wires and the central composite skeleton 7 after cabling, for constraint and positioning. The elastic moisture-absorbing buffer strip 9 is spirally wound on the outside of the cabling wrapping layer 8, and its outer surface forms elastic contact with the inner surface of the radial moisture-proof layer 10. The radial moisture-proof layer 10 includes a longitudinally wrapped aluminum-plastic composite tape layer and a polyethylene layer extruded on its outer side. The inner lining layer 11 is disposed on the outside of the radial moisture-proof layer 10. The braided reinforcement layer 12 is disposed on the outside of the inner lining layer 11 and is formed by a blend of aramid fiber and ultra-high molecular weight polyethylene fiber. The outer sheath 13 is extruded on the outside of the braided reinforcement layer 12.

[0066] In some specific embodiments, both the phase-separated water-blocking and corrosion-resistant inner protective layer 6 and the inner lining layer 11 are extruded from a water-blocking and corrosion-resistant ethylene propylene rubber composite material, which comprises the following components in parts by weight: 60-75 parts of EPDM raw rubber with Mooney viscosity ML(1+4) 100℃ of 60-69 and ethylene content of 55%-65wt% serve as the base rubber, providing ozone resistance, aging resistance and electrical insulation properties. 15-20 parts of linear low-density polyethylene, with a density of 0.918-0.922 g / cm³. 3 .

[0067] 10-15 parts of ethylene-vinyl acetate copolymer, wherein the vinyl acetate content is 25%-30%.

[0068] 3-5 parts of hydrogenated styrene-butadiene-styrene block copolymer, with a hydrogenation degree ≥98% and a molecular weight of 100,000-150,000.

[0069] Adding 8-12 parts of naphthenic oil can reduce the viscosity of the mixture and improve the dispersion of fillers.

[0070] 1.5 to 2.0 parts of peroxide crosslinking agent, which is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane with a purity ≥92%, is used as a vulcanizing agent to achieve efficient crosslinking of ethylene propylene rubber.

[0071] The antioxidant, in 2.5 to 3.5 parts, is a compound of 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid and dioctadecyl thiodipropionate in a 1:1 mass ratio, forming a main-auxiliary synergistic antioxidant system to inhibit thermo-oxidative aging.

[0072] The reinforcing filler consists of 20-30 parts, which is a compound of calcined kaolin, precipitated silica, and aluminum hydroxide in a mass ratio of 4:2:1 and surface-treated with vinyltrimethoxysilane. Aluminum hydroxide acts as an inorganic flame retardant to improve flame retardancy and electrical tracking resistance, while silica acts as a reinforcing filler to improve mechanical properties and processing characteristics.

[0073] 1.0 to 1.5 parts of titanate coupling agent, which is isopropyl tris(dioctyl pyrophosphate) titanate, is used as an interface modifier to improve the interfacial bonding between inorganic fillers and rubber matrix.

[0074] The lubricant, consisting of 2.0 to 3.0 parts, is a compound of polyethylene wax and calcium stearate in a 1:1 mass ratio. It serves as a processing aid to reduce frictional resistance during mixing and extrusion.

[0075] The water-blocking and corrosion-resistant ethylene propylene rubber composite material is formed by extrusion, with an extrusion thickness of 1.5~2.0mm, tensile strength ≥8MPa, and elongation at break ≥300%. In this composite material, linear low-density polyethylene has good compatibility with the ethylene propylene rubber matrix, which improves the system's flexibility and stress cracking resistance. 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexane achieves efficient crosslinking with low odor residue; aluminum hydroxide, as an inorganic flame retardant, synergistically improves the system's flame retardancy, electrical tracking resistance, and mechanical properties with silica. The outer surface of the phase-separated water-blocking and corrosion-resistant inner protective layer 6 has a certain roughness, forming a mechanical fit with the arc transition groove of the central composite skeleton 7, which is beneficial to improving interlayer bonding and water-blocking sealing effect; the inner lining layer 11 is extruded on the outside of the radial moisture-proof layer 10, filling the microscopic unevenness of the outer surface of the radial moisture-proof layer 10.

[0076] In some specific embodiments, the elastic moisture-absorbing buffer strip 9 is spirally wound on the outside of the cable wrapping layer 8. The elastic moisture-absorbing buffer strip 9 includes a radial elastic buffer layer, a moisture-absorbing and shaping layer, and a selectively permeable layer. The radial elastic buffer layer is a closed-cell EPDM rubber chemical foam, the matrix of which consists of 100 parts of EPDM rubber (Mooney viscosity 40-60, ethylene content 55%-65%), 3-5 parts of azodicarbonamide foaming agent (particle size 5-10 μm, gas generation 220-250 mL / g), and foaming aids. The mixture is prepared by a mixing-foaming process, consisting of 2-3 parts of an agent (a mixture of zinc oxide and zinc stearate in a 2:1 mass ratio), 0.5-1.0 parts of sulfur, 1.5-2.5 parts of an accelerator (a mixture of tetramethylthiuram disulfide and N-cyclohexyl-2-benzothiazole sulfenamide in a 1:1 mass ratio), 5-8 parts of naphthenic oil, and 10-15 parts of calcined kaolin. Other suitable foaming processes and formulations can also be used; this application does not specifically limit these. The foaming ratio is 2.5-3.5 times, and the density is 0.25-0.35 g / cm³. 3 The material has a Shore A hardness of 25-40, tensile strength ≥3MPa, closed-cell rate ≥80%, and water absorption rate ≤5%. The moisture-absorbing and shaping layer is a moisture-absorbing filler filling the internal cavity of the radial elastic buffer layer. The moisture-absorbing filler is composed of anhydrous calcium chloride (particle size 2-4mm, moisture absorption rate ≥30%) and molecular sieve 4A (particle size 1-3mm, pore size 0.38nm, water absorption rate ≥25%) in a mass ratio of 1.5:1, and its filling volume accounts for 45%-55% of the internal cavity volume of the radial elastic buffer layer. The selective moisture-permeable layer is an expanded polytetrafluoroethylene waterproof and breathable membrane coated on the outer surface of the radial elastic buffer layer by hot-melt composite method, with a thickness of 0.08-0.12mm and an average pore size of 0.2-0.5μm. The elastic moisture-absorbing buffer strip 9 is set on the outside of the cable wrapping layer 8 in a spiral winding manner, with a pitch of 40-60mm, a width of 18-22mm, and a thickness of 3-5mm. The radial elastic buffer layer absorbs mechanical vibration and thermal expansion differences, while the selective moisture-permeable layer allows gaseous water molecules to pass through and be absorbed by the moisture-absorbing filler, while preventing liquid water from entering directly. The outer surface of the elastic moisture-absorbing buffer strip 9 forms an elastic contact with the inner surface of the longitudinal wrapping layer of the aluminum-plastic composite strip, which helps to maintain the roundness between layers and allows for a certain degree of radial deformation.

[0077] In some specific embodiments, the radial moisture barrier 10 includes an aluminum-plastic composite tape longitudinal wrapping layer and a polyethylene layer extruded on its outer side. Optionally, the aluminum-plastic composite tape longitudinal wrapping layer can adopt a three-layer composite structure, including an aluminum foil layer in the middle and ethylene-methacrylic acid copolymer (EMAA) layers respectively laminated on the inner and outer sides of the aluminum foil layer; wherein, the aluminum foil layer can be made of 8011-O aluminum alloy with a thickness of 0.25~0.30mm; the aluminum-plastic composite tape longitudinal wrapping layer is wrapped on the outer side of the elastic moisture-absorbing buffer strip 9 in a longitudinal wrapping manner; the polyethylene layer can be selected from high-density polyethylene (HDPE) and is wrapped on the outer side of the aluminum-plastic composite tape longitudinal wrapping layer by an extrusion process with an extrusion thickness of 1.5~2.5mm; the polyethylene layer and the EMAA layer on the outer side of the aluminum-plastic composite tape longitudinal wrapping layer come into contact and cool and solidify at the high temperature of extrusion to form a physical interlocking interface. The polar groups in the EMAA layer can form an interface bond with the aluminum foil surface, thereby preventing moisture from penetrating radially along the cable through the sealing effect of the overlap seam and the interlayer interface.

[0078] In some specific embodiments, the braided reinforcement layer 12 is disposed on the outside of the inner lining layer 11 and is formed by blending aramid fibers and ultra-high molecular weight polyethylene fibers. Optionally, the aramid fibers can be aramid 1414 or other aramid fibers with high strength and high modulus; the mass ratio of aramid fibers to ultra-high molecular weight polyethylene fibers is 60:40, and the specific ratio can be adjusted according to mechanical performance and cost requirements. This application does not specifically limit this ratio. The braiding angle of the braided reinforcement layer 12 is 45°~55°, and the braiding density is not less than 85%. Since aramid fibers have high tensile strength and ultra-high molecular weight polyethylene fibers have high elastic modulus and good chemical corrosion resistance, the blending of the two can form complementary properties, which is beneficial to improving the comprehensive mechanical properties and salt spray resistance of the braided reinforcement layer 12.

[0079] In some specific embodiments, the outer sheath 13 may be made of corrosion-resistant and water-blocking polyethylene composite material, or other sheath materials with corrosion resistance, water blocking and mechanical protection properties. This application does not make specific limitations on this. Its thickness is 2.5~3.5mm, and the specific thickness can be adjusted according to the laying environment and mechanical protection requirements. By extruding it onto the outer layer of the cable, it can provide the cable with external mechanical protection and seawater corrosion resistance.

[0080] Unless otherwise specified, all the above layers can be prepared using existing methods in the art, such as extrusion molding, coating, wrapping, and braiding. The specific process can be selected according to the material properties and structural requirements of each layer, and this application does not impose any specific limitations on it. Those skilled in the art, with a full understanding of the above technical solutions and in conjunction with conventional techniques in the art, can realize the preparation of the cable of this application.

Claims

1. A 10kV power cable for coastal areas, characterized in that, include: The three single-core insulated wire cores, each of which, from the inside out, includes a conductor, a conductor shielding layer, an insulation layer, an insulation shielding layer, a phase-separated metal shielding layer, and a phase-separated water-blocking and corrosion-resistant inner protective layer; The central composite skeleton has a triangular cross-section, with arc transition grooves formed at its three vertices, and the three single-core insulated wire cores are correspondingly embedded in the arc transition grooves. The central composite skeleton includes a skeleton matrix, a central reinforcing core embedded in the center of the skeleton matrix and extending along the axial direction, and a multilayer composite coating disposed on the outer surface of the skeleton matrix. The skeleton matrix has multiple through-holes along the axial direction inside. The multi-layer composite coating comprises, from the inside out, a plasma activation layer, a moisture-curing polyurethane hot melt adhesive primer layer, and an asphalt affinity transition layer. The through-hole and the annular space between the three single-core insulated wire cores and the central composite skeleton are filled with modified asphalt castings; the central composite skeleton improves structural stability and waterproof reliability. And a multi-layered outer sheath that sequentially covers the three single-core insulated wires and the outer side of the central composite skeleton after cabling, from the inside out.

2. The 10kV water-resistant, salt spray-resistant, and corrosion-resistant power cable for coastal areas according to claim 1, characterized in that, The skeleton matrix is ​​made of basalt fiber reinforced polybutylene terephthalate, wherein the mass fraction of basalt fiber is 25%~35%; The central reinforcing core is made of galvanized aluminum-magnesium alloy steel wire.

3. The 10kV water-blocking, salt spray-resistant, and corrosion-resistant power cable for coastal areas according to claim 1, characterized in that, The bitumen affinity transition layer comprises the following components in parts by weight: 10-15 parts of star-shaped styrene-ethylene-butene-styrene block copolymer, with a weight-average molecular weight of 200,000-300,000 and a styrene segment mass fraction of 32%-35%; 8-12 parts of random polypropylene, with a weight-average molecular weight of 10,000-30,000; 75-82 parts of petroleum asphalt; 2-3 parts of hydrophobic fumed silica, with a specific surface area of ​​100-160 m² 2 / g, with a particle size of 12~20nm; The thickness of the asphalt affinity transition layer is 0.5~1.0 mm.

4. The 10kV water-resistant, salt spray-resistant, and corrosion-resistant power cable for coastal areas according to claim 1, characterized in that, The modified asphalt casting body comprises the following components in parts by weight: 60-70 parts of petroleum asphalt; 10-20 parts of nano-halostone tube-supported polyether-type polyurethane prepolymer composite modified powder; 8-12 parts of ethylene-ethyl acrylate copolymer; 3-5 parts of random polypropylene; Citric acid 0.2~0.4 parts; Antioxidant 0.4~0.6 parts; 3-4 parts of hydrophobic fumed silica; 1.5 to 2.5 parts organic bentonite; Benzotriazole 1.0~1.5 parts; 5-10 parts of water-absorbing and swelling polyurethane microspheres; 1-2 parts of dimethyl silicone oil.

5. The 10kV water-resistant, salt spray-resistant, and corrosion-resistant power cable for coastal areas according to claim 1, characterized in that, The insulating layer is made of modified polypropylene-based insulating material, which comprises the following components in parts by weight: 70-80 parts of homopolymer polypropylene; 8-12 parts of ethylene-butyl acrylate copolymer; 5-10 parts of silane-grafted polypropylene; 4-6 parts of fluorosilane-modified hexagonal boron nitride; Nucleating agent 0.1~0.2 parts; Antioxidant 0.2~0.4 parts; Lubricant 0.1~0.2 parts; The silane-grafted polypropylene is formed by melt grafting vinyltrimethoxysilane onto polypropylene under the initiation of dicumyl peroxide, with a grafting rate of 1.5-2.5%; the fluorosilane-modified hexagonal boron nitride is surface-treated with tridecafluorooctyltriethoxysilane, with a particle size of 100-500 nm and a sheet thickness of 10-50 nm.

6. The 10kV water-resistant, salt spray-resistant, and corrosion-resistant power cable for coastal areas according to claim 1, characterized in that, The phase-separated metal shielding layer is a tin-plated copper strip overlapping and wrapping structure; the outer surface of the tin-plated copper strip is coated with a graphene oxide / γ-aminopropyltriethoxysilane composite coating; and the inner surface of the tin-plated copper strip is coated with a semi-conductive adhesive.

7. The 10kV water-resistant, salt spray-resistant, and corrosion-resistant power cable for coastal areas according to claim 1, characterized in that, The multi-layered outer sheath, from the inside out, includes a cable wrapping layer, an elastic moisture-absorbing buffer strip, a radial moisture-proof layer, an inner lining layer, a braided reinforcement layer, and an outer sheath.

8. The 10kV water-resistant, salt spray-resistant, and corrosion-resistant power cable for coastal areas according to claim 7, characterized in that, Both the phase-separated water-blocking and corrosion-resistant inner protective layer and the inner lining layer are extruded from a water-blocking and corrosion-resistant ethylene propylene rubber composite material, which comprises the following components by weight: 60-75 parts of EPDM raw rubber; 15-20 parts of linear low-density polyethylene; 10-15 parts of ethylene-vinyl acetate copolymer; 3-5 parts of hydrogenated styrene-butadiene-styrene block copolymer; 8-12 parts of naphthenic oil; Peroxide crosslinking agent 1.5~2.0 parts; Antioxidant 2.5~3.5 parts; 20-30 parts of reinforcing filler; 1.0 to 1.5 parts of titanate coupling agent; 2.0~3.0 parts of lubricant.

9. The 10kV water-resistant, salt spray-resistant, and corrosion-resistant power cable for coastal areas according to claim 7, characterized in that, The elastic moisture-absorbing buffer strip is spirally wound on the outside of the cable wrapping layer. The elastic moisture-absorbing buffer strip includes: Radial elastic buffer layer: Closed-cell EPDM rubber chemical foam, with a foaming ratio of 2.5~3.5 times and a density of 0.25~0.35 g / cm³. 3 Closed-cell rate ≥80%, Shore A hardness 25~40; Moisture-absorbing and shaping layer: Moisture-absorbing filler that fills the cavity inside the radial elastic buffer layer, with a filling volume accounting for 45-55% of the cavity volume inside the radial elastic buffer layer; Selective moisture-permeable layer: Expanded polytetrafluoroethylene waterproof and breathable membrane coated on the outer surface of the radial elastic buffer layer by hot-melt composite method, with a thickness of 0.08~0.12mm and an average pore size of 0.2~0.5μm.

10. The 10kV water-resistant, salt spray-resistant, and corrosion-resistant power cable for coastal areas according to claim 7, characterized in that, The radial moisture-proof layer includes an aluminum-plastic composite tape longitudinal wrapping layer and a polyethylene layer extruded on the outside of the aluminum-plastic composite tape longitudinal wrapping layer; the woven reinforcement layer is made of aramid fiber and ultra-high molecular weight polyethylene fiber mixed weave.

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