Anti-corrosion overhead line capable of reducing corona loss and preparation method thereof

Abstract

The invention discloses an anti-corrosion overhead line capable of reducing corona loss and a preparation method of the anti-corrosion overhead line, and relates to the technical field of overhead transmission line wire protection. The structure is composed of an inner graphene-carbon nanotube composite conductive ceramic bottom layer and an outer intelligent response self-repairing conductive polymer surface layer, so that the conductivity, corrosion resistance and self-repairing capability are improved, the corona loss is effectively reduced, and the service life of the overhead line is prolonged; an integrated double-layer protective coating is constructed on the surface of a wire base body, an inner-layer conductive ceramic structure effectively homogenizes an electric field and inhibits corona discharge, an outer-layer intelligent response polymer has temperature-sensitive regulation and self-repairing functions and can dynamically adapt to environmental changes and actively repair damage, and the method strengthens the corrosion resistance and penetration resistance of the overhead line and improves the service life of the overhead line. Operation loss and operation and maintenance cost are reduced, and long-term stable service of the line is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of overhead transmission line conductor protection technology, specifically to an anti-corrosion overhead line that can reduce corona loss and its preparation method. Background Technology

[0002] This invention pertains to the technical field of overhead transmission line conductor protection and performance optimization technology. Overhead transmission lines, as the core carrier of power energy transmission, are critical infrastructure supporting the safe and stable operation of power systems. With the continuous advancement of new power system construction, the power grid transmission capacity is constantly increasing, and voltage levels are continuously rising, placing more stringent requirements on the transmission efficiency, operational reliability, environmental adaptability, and service life of overhead conductors. Overhead conductors are exposed to the open environment for extended periods, directly subjected to the effects of sunlight, wind, rain, and temperature changes, while also facing corrosion from industrial corrosive media, acid rain, salt spray, and other corrosive factors, as well as the corona discharge effect under high-voltage operating conditions. Electricity causes significant energy loss, directly reducing the energy efficiency of transmission lines. Simultaneously, the accompanying electromagnetic interference and noise pollution affect the surrounding environment and communication systems. Long-term corona discharge accelerates the aging and deterioration of conductors and fittings, increasing the safety risks of line operation. Corrosion gradually destroys the structural integrity of the conductor substrate, reducing its mechanical and electrical properties, leading to problems such as strand breakage and reduced load-bearing capacity. This significantly shortens the service life of the lines and increases the cost of power grid operation and maintenance, as well as safety management pressures. Therefore, developing overhead conductor technology that can simultaneously achieve effective suppression of corona loss and long-term corrosion protection has become a core technological need urgently needing to be addressed in the field of transmission lines.

[0003] Current performance optimization and protection technologies for overhead conductors mostly adopt a single-function design approach, making it difficult to simultaneously address the dual requirements of corona loss control and corrosion protection. This results in significant technical shortcomings and application limitations. Traditional conductor corrosion protection solutions often employ single metal plating, anti-corrosion grease coating, or conventional polymer coating. During long-term field service, these protective structures are prone to plating damage and rust spread, grease loss and aging, and coating cracking and peeling. Their protective performance deteriorates rapidly, and they cannot achieve self-repair of damaged areas, making it difficult to form a long-term stable protective barrier. Optimization methods for corona loss primarily focus on adjusting the conductor structure, such as changing the conductor stranding structure and increasing... Improving the electric field distribution through methods such as adjusting the outer diameter of conductors presents challenges, including high costs for line design and modification, difficult construction, and poor compatibility with existing lines. Surface modification cannot provide convenient performance upgrades. Some surface-modified coatings used for corona suppression suffer from poor electrical compatibility with the conductor substrate and unstable conductivity, failing to suppress corona discharge while ensuring the conductor's power transmission performance and simultaneously providing corrosion protection. Furthermore, traditional multi-layer composite coating systems suffer from insufficient interlayer bonding and low performance matching, failing to achieve a synergistic protective effect. Under complex operating conditions, they are prone to interlayer peeling and delamination failure, making it difficult to meet the long-term stable service requirements of overhead conductors. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a corrosion-resistant overhead line with reduced corona loss and its preparation method. The overhead line includes a conductor substrate and a double-layer protective coating on its outer surface. From the inside out, the coating consists of a graphene-carbon nanotube composite conductive ceramic bottom layer and a smart responsive self-healing conductive polymer surface layer. Through the synergistic effect of the double coating, the overhead line has excellent conductivity, corona resistance, self-healing corrosion resistance, and smart responsive characteristics with super-hydrophilic / hydrophobic reversible changes, thereby improving the overall performance and service life of the overhead line.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: On the one hand, a corrosion-resistant overhead line that can reduce corona loss, the corrosion-resistant overhead line includes a conductor substrate, the outer surface of the conductor substrate is coated with an integrated double-layer protective coating, the integrated double-layer protective coating consists of a graphene-carbon nanotube composite conductive ceramic bottom layer and a smart response self-healing conductive polymer surface layer from the inside to the outside. The graphene-carbon nanotube composite conductive ceramic substrate comprises, by mass parts: 70-90 parts of nano-Al2O3-TiO2 composite ceramic matrix, 1-3 parts of graphene, 2-5 parts of carbon nanotubes, and 0.5-2 parts of silane coupling agent. The substrate has a thickness of 10-30 μm and a volume resistivity of [missing information]. ; The intelligent responsive self-healing conductive polymer surface layer comprises, by weight, 40-60 parts of a conductive polymer film-forming matrix, 5-10 parts of poly(N-isopropylacrylamide), 5-12 parts of bifunctional responsive microcapsules, 15-30 parts of nano-ceramic filler, 2-5 parts of anti-corrosion pigment, and 0.1-1 parts of other additives. The surface layer has a thickness of 40-90 μm and a volume resistivity of [missing information]. ; The conductive polymer film-forming matrix is ​​at least one of polypyrrole and polyaniline; the bifunctional responsive microcapsule is a compound of self-healing microcapsules and pH-responsive microcapsules, with a mass ratio of 1:1 to 2:1; and the nano-ceramic filler is at least one of Al2O3, ZrO2, and TiO2 with a particle size of 5-50 nm.

[0006] Furthermore, the conductor substrate is any one of steel-cored aluminum stranded wire, hard aluminum stranded wire, or aluminum alloy stranded wire, and the outermost monofilament surface of the conductor substrate is completely covered with an integrated double-layer protective coating; the adhesion between the integrated double-layer protective coating and the conductor substrate is >15MPa, the surface roughness Ra is <0.2μm, and the coating hardness is ≥HV1200; the intelligent response self-healing conductive polymer surface layer has a water contact angle <10° at room temperature of 25℃ and a water contact angle >90° at high temperature of >38℃.

[0007] Furthermore, the graphene is 1-5 layers of hydroxylated few-layer graphene with a sheet diameter of 1-5 μm and a specific surface area of ​​300-500 m². 2 / g, carbon purity ≥99%, oxygen content ≤3%; carbon nanotubes are hydroxylated modified multi-walled carbon nanotubes with a diameter of 10-50nm, a length of 1-20μm, an aspect ratio of 100-1000, and a purity ≥95%; in the nano-Al2O3-TiO2 composite ceramic matrix, the mass ratio of Al2O3 to TiO2 is 3:1-5:1, Al2O3 is α-corundum phase, TiO2 is rutile phase, and the original particle size of the powder is 20-100nm; the silane coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane.

[0008] Furthermore, the conductive polymer film-forming matrix is ​​a mixture of polypyrrole and polyaniline in a mass ratio of 1:1 to 3:1; the number average molecular weight of polyN-isopropylacrylamide is 8000-20000, and the low critical dissolution temperature is 32-38℃; the nano-ceramic filler is a mixture of Al2O3 and ZrO2 with a particle size of 5-50nm in a mass ratio of 2:1 to 4:1, and the surface is modified with a silane coupling agent; the anti-corrosion pigment is at least one of zinc phosphate and aluminum tripolyphosphate with a particle size ≤10μm; other additives include dispersants, defoamers, and film-forming aids.

[0009] Furthermore, the self-healing microcapsules have a wall made of urea-formaldehyde resin or melamine-formaldehyde resin with a wall thickness of 1-3 μm and a particle size of 5-30 μm. The core is a mixture of conductive polymer monomers and polymerization catalysts in a mass ratio of 5:1-10:1, with a core material coverage rate ≥80wt%. The pH-responsive microcapsules have a wall made of chitosan-acrylic acid resin copolymer with a wall thickness of 2-4 μm and a particle size of 10-50 μm. The core is a zinc phosphate corrosion inhibitor or a benzotriazole corrosion inhibitor with a core material coverage rate ≥75wt%. The corrosion inhibitor is automatically released in an acidic environment with pH < 5.6.

[0010] On the other hand, a method for preparing a corrosion-resistant overhead line that can reduce corona loss includes the following steps: S1. Pretreatment of conductor substrate: The outer monofilament surface of the conductor substrate is degreased, sandblasted, acid-washed and phosphated in sequence, and then surface modified with silane coupling agent ethanol solution, and dried for later use. S2. Preparation of conductive ceramic substrate deposition: Prepare pulsed electrochemical deposition electrolyte, use the pretreated wire substrate as cathode and stainless steel as anode, and use pulsed power supply to perform electrochemical deposition to grow graphene-carbon nanotube composite conductive ceramic substrate in situ on the surface of the wire substrate. After deposition, wash with water and dry. S3. Preparation of composite emulsion: Conductive polymer monomers, deionized water and emulsifier are mixed and a conductive polymer emulsion is prepared by in-situ polymerization. Then, poly-N-isopropylacrylamide, bifunctional responsive microcapsules, nano-ceramic fillers, anti-corrosion pigments and other additives are added to the emulsion. After high-speed dispersion and sand milling, the solid content is adjusted to 30-40% to obtain composite emulsion. S4. Surface coating molding: The composite emulsion is coated onto the surface of the graphene-carbon nanotube composite conductive ceramic substrate using electrostatic spraying or dip coating processes, and leveled at room temperature to obtain the coating preform. S5. Double-layer coating synergistic curing: The coating preform is subjected to low-temperature hot air pre-curing, ultrasonic-assisted curing, and low-temperature plasma surface modification treatment in sequence to obtain an anti-corrosion overhead line that can reduce corona loss.

[0011] Furthermore, the degreasing process uses anhydrous ethanol or aviation kerosene as a solvent and is performed ultrasonically at a constant temperature of 40-50℃ for 15-20 minutes; the sandblasting process uses 80-120 mesh white corundum abrasive, with a sandblasting pressure of 0.3-0.5 MPa and a sandblasting distance of 10-15 cm, resulting in a surface roughness Ra of 2-3 μm for the monofilaments after treatment; the acid pickling and phosphating treatment involves first immersing the filaments in a mixture of 5-8 wt% dilute nitric acid and 0.5-1 wt% corrosion inhibitor at room temperature for 3-5 minutes, followed by water washing until neutral, and then immersing them in a zinc-based phosphating solution at 45-55℃ for 10-15 minutes to form a phosphating film 1-3 μm thick; the silane coupling agent ethanol solution has a mass fraction of 2-5%, the surface modification immersion time is 10-20 minutes, and the drying temperature after modification is 60-80℃ for 20-30 minutes.

[0012] Furthermore, the components of the pulsed electrochemical deposition electrolyte include 20-30 g / L aluminum salt, 5-10 g / L titanium salt, 1-3 g / L graphene dispersion, 2-5 g / L carbon nanotube dispersion, 5-8 g / L boric acid, and 2-4 g / L citric acid; the electrolyte pH is 3-5; the anode and cathode are coaxially arranged, with a distance of 5-8 cm between them; the process parameters for pulsed electrochemical deposition are a pulse frequency of 1000-5000 Hz, a duty cycle of 30-50%, and a current density of 2-5 A / dm³. 2 The electrolyte temperature is 25-40℃, and the deposition time is 10-30 min. After deposition, rinse with deionized water 3-5 times, and then dry in a hot air environment at 80℃ for 10-15 min.

[0013] Furthermore, the in-situ polymerization method has a reaction temperature of 0-5℃, a reaction time of 4-6h, a molar ratio of initiator to conductive polymer monomer of 1:1, and a solid content of 40-50% in the prepared conductive polymer emulsion; the high-speed dispersion has a rotation speed of 2000-3000r / min and a dispersion time of 30min; the sand milling uses 0.6-0.8mm zirconium bead media, a sand milling speed of 1500-2000r / min, and a sand milling pass of 2-3 times, resulting in an emulsion fineness ≤20μm after sand milling; the bifunctional responsive microcapsules are added after sand milling, with a stirring speed of 300-500r / min and a stirring time of 15-20min during the addition process.

[0014] Furthermore, the parameters of the electrostatic spraying process are: spraying voltage 30-50kV, spraying distance 15-25cm, spray gun moving speed 5-10m / min, and 2-3 spray passes; the parameters of the dip coating process are: lifting speed 1-2m / min, immersion time 30-60s, and 2-3 lifting times; the room temperature leveling time is 10-15min.

[0015] Furthermore, the low-temperature hot air pre-curing temperature is 80-120℃, the holding time is 30-60min, and the heating rate is 2-3℃ / min; the ultrasonic-assisted curing temperature is the same as the pre-curing temperature, the ultrasonic frequency is 20-40kHz, and the processing time is 10-20min; the low-temperature plasma surface modification treatment uses argon as the working medium, the vacuum degree is 10-30Pa, the processing power is 100-300W, and the processing time is 5-15min.

[0016] Compared with existing technologies, this corrosion-resistant overhead line that can reduce corona loss and its preparation method have the following beneficial effects: I. This invention achieves synergistic optimization of conductivity, mechanical protection, and corrosion resistance by constructing an integrated double-layer protective coating system on the surface of the conductor substrate. The bottom layer is a composite conductive ceramic structure. Through the composite matching of carbon-based conductive materials and ceramic substrate, a stable and continuous conductive path is constructed, effectively homogenizing the electric field intensity on the conductor surface, suppressing the generation of corona discharge, and significantly reducing corona loss during line operation. At the same time, the ceramic substrate has excellent weather resistance and wear resistance, which can form a rigid protective barrier for the conductor substrate, isolating the intrusion of external corrosive media. It also has a very strong bonding force with the substrate, avoiding the problem of coating peeling and cracking during long-term operation. This ensures the long-term stable service of the line in complex outdoor environments and provides reliable structural support for low-loss and long-cycle operation of overhead transmission lines.

[0017] II. This invention introduces a smart responsive self-healing conductive polymer system into the surface of the protective coating, combined with bifunctional responsive microcapsules and temperature-sensitive functional components, to achieve dynamic regulation and self-repair of the coating's protective performance. The temperature-sensitive components can adaptively adjust the surface wetting characteristics according to the temperature changes of the line's operating environment. Under high-temperature operating conditions, they form a hydrophobic protective interface to block liquid media such as rainwater and condensation, while under low-temperature conditions, they restore hydrophilic properties to prevent the adhesion and accumulation of surface contaminants. The bifunctional responsive microcapsules can quickly release the corresponding functional components when the coating suffers mechanical damage or localized corrosion and acidification, repairing the conductive pathways and protective barriers, and actively inhibiting the spread of corrosion. At the same time, combined with nano-ceramic fillers and anti-corrosion pigments, the coating's anti-permeability and long-term protective life are further enhanced, reducing the operation and maintenance costs and failure risks of overhead lines.

[0018] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0020] Figure 1 A flowchart illustrating the steps involved in preparing a corrosion-resistant overhead line that can reduce corona loss; Figure 2 A flowchart illustrating a method for preparing a corrosion-resistant overhead line that can reduce corona loss; Figure 3 This is a flowchart illustrating the preparation steps of the composite emulsion of the present invention. Detailed Implementation

[0021] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0022] Example 1: This embodiment provides a corrosion-resistant overhead line that reduces corona loss. The conductor substrate uses steel-cored aluminum stranded wire, and the outermost single filament surface of the conductor substrate is completely covered with an integrated double-layer protective coating. The integrated double-layer protective coating, from the inside out, consists of a graphene-carbon nanotube composite conductive ceramic bottom layer and a smart responsive self-healing conductive polymer surface layer, such as... Figure 1 As shown.

[0023] The graphene-carbon nanotube composite conductive ceramic substrate, by mass parts, comprises 80 parts of nano-Al₂O₃-TiO₂ composite ceramic matrix, 2 parts of graphene, 3 parts of carbon nanotubes, and 1 part of silane coupling agent. The substrate thickness is 20 μm, and the volume resistivity is [missing value]. In the nano-Al₂O₃-TiO₂ composite ceramic matrix, the mass ratio of Al₂O₃ to TiO₂ is 4:1. Al₂O₃ is the α-corundum phase, and TiO₂ is the rutile phase. The original particle size of the powder is 50 nm. The graphene is a 3-layer hydroxylated few-layer graphene with a sheet diameter of 3 μm and a specific surface area of ​​400 m². 2 / g, carbon purity 99.5%, oxygen content 2%. The carbon nanotubes are hydroxylated modified multi-walled carbon nanotubes with a diameter of 30nm, a length of 10μm, an aspect ratio of 500, and a purity of 98%. The silane coupling agent is γ-aminopropyltriethoxysilane.

[0024] The intelligent responsive self-healing conductive polymer surface layer, by weight, comprises 50 parts of a conductive polymer film-forming matrix, 8 parts of poly(N-isopropylacrylamide), 8 parts of bifunctional responsive microcapsules, 20 parts of nano-ceramic filler, 3 parts of anti-corrosion pigment, and 0.5 parts of other additives. The surface layer thickness is 60 μm, and the volume resistivity is [missing information]. The conductive polymer film-forming matrix is ​​a mixture of polypyrrole and polyaniline in a 2:1 mass ratio. The number-average molecular weight of polyN-isopropylacrylamide is 15,000, and its lower critical solution temperature is 35℃. The bifunctional responsive microcapsules are a mixture of self-healing microcapsules and pH-responsive microcapsules in a 1.5:1 mass ratio. The nano-ceramic filler is a mixture of Al₂O₃ and ZrO₂ with a particle size of 30 nm in a 3:1 mass ratio, with the surface modified by a silane coupling agent. The anti-corrosion pigment is zinc phosphate with a particle size of 8 μm. Other additives include dispersants, defoamers, and film-forming aids. The self-healing microcapsules have a urea-formaldehyde resin wall with a thickness of 2 μm and a particle size of 20 μm. The core is a mixture of conductive polymer monomers and polymerization catalysts in an 8:1 mass ratio, with a core material coverage of 85 wt%. The pH-responsive microcapsules have a chitosan-acrylic resin copolymer wall with a thickness of 3 μm and a particle size of 30 μm. The core is a benzotriazole corrosion inhibitor with a core material coverage of 80 wt%. The corrosion inhibitor is automatically released in an acidic environment with a pH less than 5.6.

[0025] The corrosion-resistant overhead line with reduced corona loss in this embodiment is prepared through the following steps: S1. Conductor Substrate Pretreatment: Steel-cored aluminum stranded wire was selected as the conductor substrate. The outer monofilament surface of the conductor substrate underwent degreasing, sandblasting, acid pickling, and phosphating treatments in sequence. Then, surface modification treatment was performed using a silane coupling agent ethanol solution, followed by drying. Degreasing was performed using anhydrous ethanol as the solvent, with ultrasonic degreasing at a constant temperature of 45℃ for 18 minutes to remove oil, dust, and other impurities from the monofilament surface, ensuring sufficient contact between the substrate surface and the treatment solution during subsequent processing. Sandblasting used 100-mesh white corundum abrasive at a pressure of 0.4 MPa and a distance of 12 cm. After treatment, the surface roughness of the monofilament was Ra 2.5 μm. Sandblasting created a uniform micro-rough structure on the monofilament surface, improving the adhesion between the subsequent coating and the substrate. The pickling and phosphating treatment involves first immersing the filament in a mixture of 6wt% dilute nitric acid and 0.8wt% corrosion inhibitor at room temperature for 4 minutes to remove the oxide layer and rust products from the surface. After rinsing with water until neutral, the filament is immersed in a zinc-based phosphating solution at 50℃ for 12 minutes to form a 2μm thick phosphating film. This phosphating film provides temporary corrosion protection for the substrate and further improves the adhesion between the coating and the substrate. The silane coupling agent ethanol solution has a mass fraction of 3%, and the surface modification immersion time is 15 minutes. After modification, the drying temperature is 70℃ and the drying time is 25 minutes. Through surface modification with the silane coupling agent, active functional groups are introduced into the substrate surface, improving the interfacial compatibility between the substrate and the subsequently deposited ceramic underlayer.

[0026] S2. Preparation of Conductive Ceramic Substrate Deposition: A pulsed electrochemical deposition electrolyte was prepared. Using a pretreated wire substrate as the cathode and stainless steel as the anode, electrochemical deposition was performed using a pulsed power supply to grow a graphene-carbon nanotube composite conductive ceramic substrate in situ on the surface of the wire substrate. After deposition, the substrate was washed with water and dried. The pulsed electrochemical deposition electrolyte consisted of 25 g / L aluminum salt, 8 g / L titanium salt, 2 g / L graphene dispersion, 3 g / L carbon nanotube dispersion, 6 g / L boric acid, and 3 g / L citric acid, with a pH of 4. Aluminum nitrate was used as the aluminum salt, and titanium oxysulfate was used as the titanium salt. Both the graphene and carbon nanotube dispersions were aqueous dispersion systems. A silane coupling agent consistent with the substrate formulation was used as the dispersant to ensure the stability of the dispersion system and the consistency of the components. The anode and cathode were arranged coaxially with a distance of 6 cm between them. This coaxial arrangement ensured a uniform electric field distribution throughout the circumference of the wire substrate, thereby guaranteeing a uniform thickness and consistent performance of the deposited ceramic substrate. The process parameters for pulsed electrochemical deposition were: pulse frequency 3000 Hz, duty cycle 40%, and current density 3 A / dm³. 2The electrolyte temperature was 30℃, and the deposition time was 20 min. Pulsed electrochemical deposition was employed to avoid concentration polarization issues that occur during continuous deposition, improving the density and uniformity of the ceramic substrate. Simultaneously, it achieved uniform doping and in-situ composite of graphene and carbon nanotubes in the ceramic matrix. After deposition, the substrate was rinsed four times with deionized water and then dried in an 80℃ hot air environment for 12 min to remove residual electrolyte and moisture from the substrate surface, preventing residual components from adversely affecting subsequent surface coatings.

[0027] S3. Preparation of Composite Emulsion: Conductive polymer monomers, deionized water, and emulsifiers are mixed and a conductive polymer emulsion is prepared by in-situ polymerization. Poly(N-isopropylacrylamide), bifunctional responsive microcapsules, nano-ceramic fillers, anti-corrosion pigments, and other additives are then added to the emulsion. After high-speed dispersion and sand milling, the solid content is adjusted to 35% to obtain the composite emulsion. The reaction temperature of the in-situ polymerization method is 3℃, the reaction time is 5h, the molar ratio of initiator to conductive polymer monomer is 1:1, and the solid content of the prepared conductive polymer emulsion is 45%. The conductive polymer monomer is a mixture of pyrrole and aniline in a mass ratio of 2:1. Ammonium persulfate is used as the initiator, and sodium dodecylbenzenesulfonate is used as the emulsifier. The entire in-situ polymerization process is carried out under a nitrogen protective atmosphere to avoid monomer oxidation and ensure that the prepared conductive polymer emulsion has stable conductivity and film-forming properties. The high-speed dispersion speed is 2500 r / min, and the dispersion time is 30 min. High-speed dispersion initially and uniformly disperses each solid component in the emulsion, breaking up the agglomeration structure of the powder. The sand milling process used 0.7mm zirconium beads as the grinding medium, at a speed of 1800 rpm, and consisted of two passes. After sand milling, the emulsion fineness was ≤20μm. This sand milling further refined the powder particle size, ensuring the uniformity and stability of the emulsion system and preventing pinhole defects in subsequent coatings caused by large particles. The bifunctional responsive microcapsules were added after sand milling, with a stirring speed of 400 rpm for 18 minutes. This low-speed stirring method prevented the microcapsule walls from rupturing due to high-speed shearing, ensuring the microcapsules maintained their intact structure within the emulsion. This allowed them to perform their corresponding responsive functions during coating service. Figure 3 As shown.

[0028] S4. Surface Coating Forming: An electrostatic spraying process is used to coat the composite emulsion onto the surface of the graphene-carbon nanotube composite conductive ceramic substrate. Leveling is then performed at room temperature to obtain the pre-formed coating. The electrostatic spraying parameters are: spraying voltage 40kV, spraying distance 20cm, spray gun movement speed 8m / min, and 2 spray passes. The electrostatic spraying process ensures uniform coating of the composite emulsion onto the substrate surface and utilizes electrostatic adsorption to enhance the coating's coverage of the substrate, ensuring uniform surface thickness throughout the conductor's circumference. The room temperature leveling time is 12min, which eliminates spraying marks on the coating surface, resulting in a smooth and flat surface structure, reducing surface roughness, and thus optimizing the electric field distribution on the conductor surface.

[0029] S5. Synergistic Curing of Two-Layer Coatings: The pre-formed coating is sequentially subjected to low-temperature hot air pre-curing, ultrasonic-assisted curing, and low-temperature plasma surface modification treatment to obtain the finished product. The low-temperature hot air pre-curing temperature is 100℃, the holding time is 45 min, and the heating rate is 2.5℃ / min. This slow heating allows the solvent in the coating to evaporate slowly, avoiding defects such as pinholes caused by rapid solvent evaporation. Simultaneously, it allows the coating to form a preliminary cross-linked structure, ensuring the basic morphology of the coating. The ultrasonic-assisted curing temperature is the same as the pre-curing temperature, the ultrasonic frequency is 30kHz, and the treatment time is 15 min. Through the cavitation effect of ultrasound, the cross-linking reaction inside the coating is fully promoted, while eliminating micro-bubbles within the coating, improving the density and interlayer bonding of the coating, and achieving synergistic curing and bonding between the bottom and top layers. Low-temperature plasma surface modification treatment uses argon as the working medium, with a vacuum degree of 20 Pa, a treatment power of 200 W, and a treatment time of 10 min. Through low-temperature plasma treatment, polar groups are introduced into the coating surface, which further optimizes the surface properties of the coating, while improving the surface density of the coating and enhancing its protective performance.

[0030] Example 2: This embodiment provides a corrosion-resistant overhead line that reduces corona loss. The conductor substrate is made of aluminum alloy stranded wire, and the outermost single filament surface of the conductor substrate is completely covered with an integrated double-layer protective coating. The integrated double-layer protective coating consists of, from the inside out, a graphene-carbon nanotube composite conductive ceramic bottom layer and a smart responsive self-healing conductive polymer surface layer, such as… Figure 2 As shown.

[0031] The graphene-carbon nanotube composite conductive ceramic substrate, by mass parts, comprises 90 parts of nano-Al₂O₃-TiO₂ composite ceramic matrix, 3 parts of graphene, 5 parts of carbon nanotubes, and 2 parts of silane coupling agent. The substrate thickness is 30 μm, and the volume resistivity is [missing value]. In the nano-Al₂O₃-TiO₂ composite ceramic matrix, the mass ratio of Al₂O₃ to TiO₂ is 5:1, with Al₂O₃ representing the α-corundum phase and TiO₂ representing the rutile phase. The original particle size of the powder is 100 nm. The graphene is a 5-layer hydroxylated few-layer graphene with a sheet diameter of 5 μm and a specific surface area of ​​500 m². 2 / g, carbon purity 99%, oxygen content 3%. The carbon nanotubes are hydroxylated modified multi-walled carbon nanotubes with a diameter of 50nm, a length of 20μm, an aspect ratio of 1000, and a purity of 95%. The silane coupling agent is γ-glycidoxypropyltrimethoxysilane.

[0032] The intelligent responsive self-healing conductive polymer surface layer, by weight, comprises 60 parts of a conductive polymer film-forming matrix, 10 parts of poly(N-isopropylacrylamide), 12 parts of bifunctional responsive microcapsules, 30 parts of nano-ceramic filler, 5 parts of anti-corrosion pigment, and 1 part of other additives. The surface layer has a thickness of 90 μm and a volume resistivity of [missing information]. The conductive polymer film-forming matrix is ​​a mixture of polypyrrole and polyaniline in a 3:1 mass ratio. The number-average molecular weight of polyN-isopropylacrylamide is 20,000, and its lower critical solution temperature is 38℃. The bifunctional responsive microcapsules are a mixture of self-healing microcapsules and pH-responsive microcapsules in a 2:1 mass ratio. The nano-ceramic filler is a mixture of Al₂O₃ and ZrO₂ with a particle size of 50 nm in a 4:1 mass ratio, with the surface modified by a silane coupling agent. The anti-corrosion pigment is aluminum tripolyphosphate with a particle size of 10 μm. Other additives include dispersants, defoamers, and film-forming aids. The self-healing microcapsule's capsule wall is made of melamine-formaldehyde resin with a wall thickness of 3 μm and a particle size of 30 μm. The core is a mixture of conductive polymer monomers and polymerization catalysts in a 10:1 mass ratio, with a core material coverage of 80 wt%. The pH-responsive microcapsules have a chitosan-acrylic resin copolymer wall with a thickness of 4 μm and a particle size of 50 μm. The core is a zinc phosphate corrosion inhibitor with a core material coverage of 75 wt%. The corrosion inhibitor is automatically released in an acidic environment with a pH less than 5.6.

[0033] The corrosion-resistant overhead line with reduced corona loss in this embodiment is prepared through the following steps: S1. Conductor Substrate Pretreatment: Aluminum alloy stranded wire was selected as the conductor substrate. The outer monofilament surface of the conductor substrate underwent degreasing, sandblasting, acid pickling, and phosphating treatment in sequence. Then, surface modification treatment was performed using a silane coupling agent ethanol solution, followed by drying. Degreasing was performed using aviation kerosene as a solvent, and ultrasonic degreasing was carried out at a constant temperature of 50℃ for 20 minutes to thoroughly remove rolling oil and impurities from the monofilament surface, ensuring the cleanliness of the substrate surface. Sandblasting used 120-mesh white corundum abrasive, with a sandblasting pressure of 0.5MPa and a sandblasting distance of 15cm. After treatment, the surface roughness of the monofilament was Ra3μm. Sandblasting created a uniform rough interface, providing sufficient mechanical interlocking sites for coating adhesion. The pickling and phosphating treatment involves first immersing the filament in a mixture of 8wt% dilute nitric acid and 1wt% corrosion inhibitor at room temperature for 5 minutes to thoroughly remove the dense oxide layer on the surface of the monofilament. After rinsing with water until neutral, the filament is immersed in a zinc-based phosphating solution at 55℃ for 15 minutes to form a 3μm thick phosphating film, providing stronger temporary corrosion protection for the substrate and further improving interfacial bonding performance. The silane coupling agent ethanol solution has a mass fraction of 5%, the surface modification immersion time is 20 minutes, and the post-modification drying temperature is 80℃ for 30 minutes. Through sufficient surface modification, a high-density layer of active functional groups is constructed on the substrate surface, enhancing the interfacial bonding between the substrate and the ceramic substrate.

[0034] S2. Preparation of Conductive Ceramic Substrate Deposition: A pulsed electrochemical deposition electrolyte was prepared. Using the pretreated wire substrate as the cathode and stainless steel as the anode, electrochemical deposition was performed using a pulsed power supply to grow a graphene-carbon nanotube composite conductive ceramic substrate in situ on the surface of the wire substrate. After deposition, the substrate was washed with water and dried. The components of the pulsed electrochemical deposition electrolyte included 30 g / L aluminum salt, 10 g / L titanium salt, 3 g / L graphene dispersion, 5 g / L carbon nanotube dispersion, 8 g / L boric acid, and 4 g / L citric acid. The pH of the electrolyte was 5. Aluminum nitrate was used as the aluminum salt, and titanium oxysulfate was used as the titanium salt. Both the graphene and carbon nanotube dispersions were aqueous dispersion systems. The dispersant used was a silane coupling agent consistent with the substrate formulation to ensure the long-term stability of the dispersion system. The anode and cathode were arranged coaxially with a distance of 8 cm between them to ensure a uniform circumferential electric field distribution on the wire substrate and avoid uneven deposition thickness. The process parameters for pulsed electrochemical deposition were: pulse frequency 5000 Hz, duty cycle 50%, and current density 5 A / dm³. 2 The electrolyte temperature was 40℃, and the deposition time was 30 minutes. High-frequency pulse deposition further improved the density of the ceramic substrate, enhancing its impermeability and mechanical properties. After deposition, the substrate was rinsed five times with deionized water and then dried in an 80℃ hot air environment for 15 minutes to thoroughly remove residual electrolyte and moisture, ensuring a clean and dry substrate surface.

[0035] S3. Preparation of Composite Emulsion: Conductive polymer monomers, deionized water, and emulsifiers are mixed and a conductive polymer emulsion is prepared by in-situ polymerization. Poly(N-isopropylacrylamide), bifunctional responsive microcapsules, nano-ceramic fillers, anti-corrosion pigments, and other additives are then added to the emulsion. After high-speed dispersion and sand milling, the solid content is adjusted to 40% to obtain the composite emulsion. The reaction temperature of the in-situ polymerization method is 5℃, the reaction time is 6h, the molar ratio of initiator to conductive polymer monomer is 1:1, and the solid content of the prepared conductive polymer emulsion is 50%. The conductive polymer monomer is a mixture of pyrrole and aniline in a mass ratio of 3:1. Ammonium persulfate is used as the initiator, and sodium dodecylbenzenesulfonate is used as the emulsifier. The entire in-situ polymerization process is carried out under a nitrogen protective atmosphere to ensure the stability of the polymer's molecular structure and excellent conductivity. The high-speed dispersion speed is 3000 r / min, and the dispersion time is 30 min to fully break up powder agglomeration and achieve preliminary uniform dispersion of each component. The milling process used 0.8mm zirconium beads as the grinding medium, at a milling speed of 2000 rpm, and for three passes. The resulting emulsion fineness was ≤20μm. Multiple milling passes ensured thorough powder refinement and a uniform and stable emulsion system. The bifunctional responsive microcapsules were added after milling, with a stirring speed of 500 rpm for 20 minutes. This low-speed, gentle stirring method avoided damage to the microcapsule walls and ensured the functional integrity of the microcapsules.

[0036] S4. Surface Coating Forming: A dip-coating process is used to coat the composite emulsion onto the surface of the graphene-carbon nanotube composite conductive ceramic substrate. Leveling is achieved at room temperature to obtain the coating preform. The dip-coating parameters are: pull-up speed 2 m / min, immersion time 60 s, and 3 pull-ups. This dip-coating process ensures that even the gaps in the stranded wires are completely covered by the coating, achieving comprehensive protection of the conductor substrate and meeting the protection requirements of heavily corrosive environments. The room temperature leveling time is 15 min to effectively eliminate flow marks on the coating surface, ensuring a smooth and even surface.

[0037] S5. Synergistic Curing of Two-Layer Coatings: The pre-formed coating is sequentially subjected to low-temperature hot air pre-curing, ultrasonic-assisted curing, and low-temperature plasma surface modification treatment to obtain the finished product. The low-temperature hot air pre-curing temperature is 120℃, the holding time is 60 min, and the heating rate is 3℃ / min. This slow pre-curing allows the coating to fully cross-link and form a stable structure. The ultrasonic-assisted curing temperature is the same as the pre-curing temperature, the ultrasonic frequency is 40kHz, and the treatment time is 20 min. Ultrasonic waves further enhance the coating's density, eliminate internal defects, and strengthen the synergistic bonding between the bottom and top layers. The low-temperature plasma surface modification treatment uses argon gas as the working medium, a vacuum degree of 30 Pa, a treatment power of 300W, and a treatment time of 15 min. This plasma treatment further optimizes the coating's surface properties and improves its weather resistance and protective performance.

[0038] Example 3: This embodiment provides a corrosion-resistant overhead line that can reduce corona loss. The conductor substrate is made of hard aluminum stranded wire, and the outermost monofilament surface of the conductor substrate is completely covered with an integrated double-layer protective coating. The integrated double-layer protective coating consists of, from the inside out, a graphene-carbon nanotube composite conductive ceramic bottom layer and a smart responsive self-healing conductive polymer surface layer.

[0039] The graphene-carbon nanotube composite conductive ceramic substrate, by mass parts, comprises 70 parts of nano-Al₂O₃-TiO₂ composite ceramic matrix, 1 part of graphene, 2 parts of carbon nanotubes, and 0.5 parts of silane coupling agent. The substrate thickness is 10 μm, and the volume resistivity is [missing value]. In the nano-Al₂O₃-TiO₂ composite ceramic matrix, the mass ratio of Al₂O₃ to TiO₂ is 3:1. Al₂O₃ is the α-corundum phase, and TiO₂ is the rutile phase. The original particle size of the powder is 20 nm. The graphene is a one-layer hydroxylated few-layer graphene with a sheet diameter of 1 μm and a specific surface area of ​​300 m². 2 / g, carbon purity 99.8%, oxygen content 1%. The carbon nanotubes are hydroxylated modified multi-walled carbon nanotubes with a diameter of 10nm, a length of 1μm, an aspect ratio of 100, and a purity of 99%. The silane coupling agent is γ-methacryloyloxypropyltrimethoxysilane.

[0040] The intelligent responsive self-healing conductive polymer surface layer, by weight, comprises 40 parts of a conductive polymer film-forming matrix, 5 parts of poly(N-isopropylacrylamide), 5 parts of bifunctional responsive microcapsules, 15 parts of nano-ceramic filler, 2 parts of anti-corrosion pigment, and 0.1 parts of other additives. The surface layer thickness is 40 μm, and the volume resistivity is [missing information]. The conductive polymer film-forming matrix is ​​a mixture of polypyrrole and polyaniline in a 1:1 mass ratio. The number-average molecular weight of poly(N-isopropylacrylamide) is 8000, and its lower critical solution temperature is 32℃. The bifunctional responsive microcapsules are a mixture of self-healing microcapsules and pH-responsive microcapsules in a 1:1 mass ratio. The nano-ceramic filler is a mixture of Al₂O₃ and ZrO₂ with a particle size of 5 nm in a 2:1 mass ratio, with the surface modified by a silane coupling agent. The anti-corrosion pigment is zinc phosphate with a particle size of 5 μm. Other additives include dispersants, defoamers, and film-forming aids. The self-healing microcapsules have a urea-formaldehyde resin wall with a thickness of 1 μm and a particle size of 5 μm. The core is a mixture of conductive polymer monomers and polymerization catalysts in a 5:1 mass ratio, with a core material coverage of 90 wt%. The pH-responsive microcapsules have a chitosan-acrylic resin copolymer wall with a thickness of 2 μm and a particle size of 10 μm. The core is a benzotriazole corrosion inhibitor with a core material coverage of 85 wt%. The corrosion inhibitor is automatically released in an acidic environment with a pH less than 5.6.

[0041] The corrosion-resistant overhead line with reduced corona loss in this embodiment is prepared through the following steps: S1. Conductor Substrate Pretreatment: Hard aluminum stranded wire was selected as the conductor substrate. The outer monofilament surface of the conductor substrate underwent degreasing, sandblasting, acid pickling, and phosphating treatment in sequence. Then, surface modification treatment was performed using a silane coupling agent ethanol solution, followed by drying. Degreasing was performed using anhydrous ethanol as the solvent, and ultrasonic degreasing was carried out at a constant temperature of 40℃ for 15 minutes to thoroughly remove impurities and oil from the monofilament surface, ensuring a clean substrate surface. Sandblasting used 80-mesh white corundum abrasive at a pressure of 0.3 MPa and a distance of 10 cm. After treatment, the surface roughness of the monofilament was Ra 2 μm. This gentle sandblasting treatment ensured coating adhesion while avoiding excessively rough structures on the substrate surface, laying the foundation for the subsequent preparation of a low-roughness coating. The pickling and phosphating treatment involves first immersing the filament in a mixture of 5wt% dilute nitric acid and 0.5wt% corrosion inhibitor at room temperature for 3 minutes to remove the oxide layer on the surface. After rinsing with water until neutral, the filament is immersed in a zinc-based phosphating solution at 45℃ for 10 minutes to form a 1μm thick phosphating film. This provides temporary corrosion protection while ensuring the smoothness of the substrate surface. The silane coupling agent ethanol solution has a mass fraction of 2%, and the surface modification immersion time is 10 minutes. After modification, the drying temperature is 60℃ and the drying time is 20 minutes. Surface modification improves the interfacial compatibility between the substrate and the ceramic underlayer.

[0042] S2. Preparation of Conductive Ceramic Substrate Deposition: A pulsed electrochemical deposition electrolyte was prepared. Using a pretreated wire substrate as the cathode and stainless steel as the anode, electrochemical deposition was performed using a pulsed power supply to grow a graphene-carbon nanotube composite conductive ceramic substrate in situ on the surface of the wire substrate. After deposition, the substrate was washed with water and dried. The pulsed electrochemical deposition electrolyte consisted of 20 g / L aluminum salt, 5 g / L titanium salt, 1 g / L graphene dispersion, 2 g / L carbon nanotube dispersion, 5 g / L boric acid, and 2 g / L citric acid, with a pH of 3. Aluminum nitrate was used as the aluminum salt, and titanium oxysulfate was used as the titanium salt. Both the graphene and carbon nanotube dispersions were aqueous dispersion systems. A silane coupling agent consistent with the substrate formulation was used as the dispersant to ensure uniform and stable dispersion. The anode and cathode were arranged coaxially with a 5 cm distance between them to ensure a highly uniform circumferential electric field distribution on the wire substrate, achieving uniform deposition of the ultrathin ceramic substrate. The process parameters for pulsed electrochemical deposition were: pulse frequency 1000 Hz, duty cycle 30%, and current density 2 A / dm³. 2 The electrolyte temperature was 25℃, and the deposition time was 10 min. Controllable growth of an ultrathin ceramic substrate was achieved through low-current-density pulse deposition, ensuring uniform substrate thickness and a smooth surface. After deposition, the substrate was rinsed three times with deionized water and then dried in an 80℃ hot air environment for 10 min to remove residual electrolyte and moisture.

[0043] S3. Preparation of Composite Emulsion: Conductive polymer monomers, deionized water, and emulsifiers are mixed and a conductive polymer emulsion is prepared by in-situ polymerization. Poly(N-isopropylacrylamide), bifunctional responsive microcapsules, nano-ceramic fillers, anti-corrosion pigments, and other additives are then added to the emulsion. After high-speed dispersion and sand milling, the solid content is adjusted to 30% to obtain the composite emulsion. The reaction temperature of the in-situ polymerization method is 0℃, the reaction time is 4h, the molar ratio of initiator to conductive polymer monomer is 1:1, and the solid content of the prepared conductive polymer emulsion is 40%. The conductive polymer monomer is a mixture of pyrrole and aniline in a 1:1 mass ratio. Ammonium persulfate is used as the initiator, and sodium dodecylbenzenesulfonate is used as the emulsifier. The entire in-situ polymerization process is carried out under a nitrogen protective atmosphere to ensure the stability of the film-forming and conductive properties of the polymer emulsion. The high-speed dispersion speed is 2000 r / min, and the dispersion time is 30 min to achieve initial uniform dispersion of each component. The sand milling process used 0.6mm zirconium beads as the grinding medium, with a milling speed of 1500 rpm and two passes. The resulting emulsion fineness was ≤15μm. This fine sand milling further refined the powder particle size, providing a foundation for preparing coatings with low surface roughness. The bifunctional responsive microcapsules were added after sand milling, with a stirring speed of 300 rpm for 15 minutes. This low-speed stirring ensured the integrity of the microcapsule structure and uniform dispersion in the emulsion.

[0044] S4. Surface Coating Forming: An electrostatic spraying process is used to coat the composite emulsion onto the surface of the graphene-carbon nanotube composite conductive ceramic substrate. Leveling is achieved at room temperature to obtain the coating preform. The electrostatic spraying parameters are: spraying voltage 30kV, spraying distance 15cm, spray gun movement speed 5m / min, and 2 spray passes. Optimized electrostatic spraying parameters ensure a highly smooth coating surface, reduce surface roughness, and optimize the electric field distribution on the conductor surface. A room temperature leveling time of 10min effectively eliminates spray marks, ensuring a smooth and flat coating surface.

[0045] S5. Synergistic Curing of Two-Layer Coatings: The pre-formed coating is sequentially subjected to low-temperature hot air pre-curing, ultrasonic-assisted curing, and low-temperature plasma surface modification treatment to obtain the finished product. The low-temperature hot air pre-curing temperature is 80℃, the holding time is 30 min, and the heating rate is 2℃ / min. Slow curing at low temperature avoids surface defects and ensures the smoothness of the coating surface. The ultrasonic-assisted curing temperature is the same as the pre-curing temperature, the ultrasonic frequency is 20kHz, and the treatment time is 10 min. Ultrasonic waves promote cross-linking of the coating, improve interlayer bonding, and simultaneously ensure the smoothness of the coating surface. The low-temperature plasma surface modification treatment uses argon as the working medium, a vacuum degree of 10Pa, a treatment power of 100W, and a treatment time of 5 min. This gentle plasma treatment optimizes the surface properties of the coating without damaging its smooth structure, ensuring extremely low surface roughness.

[0046] Comparative example: This comparative example provides a corrosion-resistant overhead line, whose conductor substrate is the same steel-cored aluminum stranded wire as in Example 1. The outermost monofilament of the conductor substrate is covered with a single anti-corrosion coating, which is a conventional epoxy anti-corrosion coating with a thickness of 80μm.

[0047] The corrosion-resistant overhead line in this comparative example was prepared through the following steps: S1. Pretreatment of conductor substrate: The processing technology in this step is completely consistent with step S1 in Example 1, and the pretreated conductor substrate is obtained for use.

[0048] S2. The anti-corrosion coating is applied and formed. Specifically, an electrostatic spraying process is used to apply a commercially available conventional epoxy anti-corrosion coating to the surface of the pretreated conductor substrate. The coating is then leveled at room temperature to obtain a pre-formed coating. The parameters of the electrostatic spraying process are completely consistent with step S4 of Example 1, and the room temperature leveling time is completely consistent with step S4 of Example 1.

[0049] S3. Coating curing: Specifically, the coating preform is cured by hot air at a curing temperature of 100℃, a holding time of 45 minutes, and a heating rate of 2.5℃ / min to obtain the finished product.

[0050] To verify the technical effect of the present invention, performance tests were conducted on the overhead line samples prepared in the above three embodiments and one comparative example. The test items included coating adhesion, surface roughness, coating hardness, corona loss reduction rate, salt spray corrosion resistance, and self-healing performance. The test results are shown in the table below.

[0051] ; The test results show that the overhead lines prepared in the various embodiments of this invention are significantly superior to conventional overhead lines in terms of coating adhesion, surface roughness, coating hardness, corona loss suppression, salt spray corrosion resistance, and self-healing performance. Each embodiment achieves synergistic optimization of corona loss reduction and corrosion protection through an integrated double-layer protective coating structure design. The graphene-carbon nanotube composite conductive ceramic structure at the bottom effectively homogenizes the electric field on the conductor surface, reducing corona loss, while providing excellent mechanical support and interfacial bonding performance. The intelligent responsive self-healing conductive polymer structure on the surface provides long-term corrosion protection for the conductor, while also achieving self-repair and environmental response functions. The technical solution of this invention effectively solves the technical problem that existing overhead lines cannot simultaneously achieve both corona loss suppression and long-term corrosion protection, and possesses excellent engineering application value.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A corrosion-resistant overhead line that can reduce corona loss, characterized in that, The corrosion-resistant overhead line includes a conductor substrate, the outer surface of which is coated with an integrated double-layer protective coating. The integrated double-layer protective coating consists of a graphene-carbon nanotube composite conductive ceramic bottom layer and a smart response self-healing conductive polymer surface layer, from the inside out. The graphene-carbon nanotube composite conductive ceramic substrate comprises, by mass parts, 70-90 parts of nano-Al2O3-TiO2 composite ceramic matrix, 1-3 parts of graphene, 2-5 parts of carbon nanotubes, and 0.5-2 parts of silane coupling agent. The intelligent responsive self-healing conductive polymer surface layer comprises, by weight, 40-60 parts of conductive polymer film-forming matrix, 5-10 parts of poly(N-isopropylacrylamide), 5-12 parts of bifunctional responsive microcapsules, 15-30 parts of nano-ceramic filler, 2-5 parts of anti-corrosion pigment, and 0.1-1 parts of other additives.

2. The corrosion-resistant overhead line with reduced corona loss according to claim 1, characterized in that, The conductor substrate is any one of steel-cored aluminum stranded wire, hard aluminum stranded wire, or aluminum alloy stranded wire, and the outermost single filament surface of the conductor substrate is completely covered with an integrated double-layer protective coating. The integrated double-layer protective coating has an adhesion to the conductor substrate of >15MPa, a surface roughness Ra of <0.2μm, and a coating hardness of ≥HV1200. The intelligent response self-healing conductive polymer surface has a water contact angle of <10° at room temperature of 25℃ and a water contact angle of >90° at high temperature of >38℃.

3. The corrosion-resistant overhead line with reduced corona loss according to claim 1, characterized in that, The graphene is a 1-5 layer hydroxylated few-layer graphene with a sheet diameter of 1-5 μm and a specific surface area of ​​300-500 m². 2 / g, carbon purity ≥99%, oxygen content ≤3%; carbon nanotubes are hydroxylated modified multi-walled carbon nanotubes with a diameter of 10-50nm, a length of 1-20μm, an aspect ratio of 100-1000, and a purity ≥95%; in the nano-Al2O3-TiO2 composite ceramic matrix, the mass ratio of Al2O3 to TiO2 is 3:1-5:1, Al2O3 is α-corundum phase, TiO2 is rutile phase, and the original particle size of the powder is 20-100nm; the silane coupling agent is at least one of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane.

4. The corrosion-resistant overhead line with reduced corona loss according to claim 1, characterized in that, The conductive polymer film-forming matrix is ​​a mixture of polypyrrole and polyaniline in a mass ratio of 1:1 to 3:1; the number average molecular weight of polyN-isopropylacrylamide is 8000-20000, and the low critical dissolution temperature is 32-38℃; the nano-ceramic filler is a mixture of Al2O3 and ZrO2 with a particle size of 5-50nm in a mass ratio of 2:1 to 4:1, and the surface is modified with a silane coupling agent; the anti-corrosion pigment is at least one of zinc phosphate and aluminum tripolyphosphate with a particle size ≤10μm; other additives include dispersants, defoamers, and film-forming aids.

5. A method for preparing a corrosion-resistant overhead line with reduced corona loss, the method being used to prepare the corrosion-resistant overhead line with reduced corona loss as described in any one of claims 1-4, characterized in that, The specific steps of this preparation method are as follows: S1. Pretreatment of conductor substrate: The outer monofilament surface of the conductor substrate is degreased, sandblasted, acid-washed and phosphated in sequence, and then surface modified with silane coupling agent ethanol solution, and dried for later use. S2. Preparation of conductive ceramic substrate deposition: Prepare pulsed electrochemical deposition electrolyte, use the pretreated wire substrate as cathode and stainless steel as anode, and use pulsed power supply to perform electrochemical deposition to grow graphene-carbon nanotube composite conductive ceramic substrate in situ on the surface of the wire substrate. After deposition, wash with water and dry. S3. Preparation of composite emulsion: Conductive polymer monomers, deionized water and emulsifier are mixed and a conductive polymer emulsion is prepared by in-situ polymerization. Then, poly-N-isopropylacrylamide, bifunctional responsive microcapsules, nano-ceramic fillers, anti-corrosion pigments and other additives are added to the emulsion. After high-speed dispersion and sand milling, the solid content is adjusted to 30-40% to obtain composite emulsion. S4. Surface coating molding: The composite emulsion is coated onto the surface of the graphene-carbon nanotube composite conductive ceramic substrate using an electrostatic spraying process, and leveled at room temperature to obtain the coating preform. S5. Synergistic curing of double-layer coating: The coating preform is subjected to low-temperature hot air pre-curing, ultrasonic-assisted curing, and low-temperature plasma surface modification treatment in sequence to obtain the finished product.

6. The method for preparing a corrosion-resistant overhead line with reduced corona loss according to claim 5, characterized in that, In step S1, the degreasing uses anhydrous ethanol or aviation kerosene as a solvent and is performed ultrasonically for 15-20 minutes at a constant temperature of 40-50℃; the sandblasting uses 80-120 mesh white corundum abrasive, with a sandblasting pressure of 0.3-0.5 MPa and a sandblasting distance of 10-15 cm, resulting in a single-wire surface roughness Ra of 2-3 μm after treatment; the acid pickling and phosphating treatment involves first immersing the wire in a mixture of 5-8 wt% dilute nitric acid and 0.5-1 wt% corrosion inhibitor for acid pickling at room temperature for 3-5 minutes, followed by water washing until neutral, and then immersing it in a zinc-based phosphating solution at 45-55℃ for phosphating for 10-15 minutes to form a phosphating film 1-3 μm thick; the silane coupling agent ethanol solution has a mass fraction of 2-5%, the surface modification immersion time is 10-20 minutes, and the drying temperature after modification is 60-80℃ for 20-30 minutes.

7. The method for preparing a corrosion-resistant overhead line with reduced corona loss according to claim 5, characterized in that, In step S2, the components of the pulse electrochemical deposition electrolyte include 20-30 g / L aluminum salt, 5-10 g / L titanium salt, 1-3 g / L graphene dispersion, 2-5 g / L carbon nanotube dispersion, 5-8 g / L boric acid, and 2-4 g / L citric acid; the pH value of the electrolyte is 3-5; the anode and cathode are arranged coaxially, and the distance between the anode and cathode is 5-8 cm; the process parameters of pulse electrochemical deposition are a pulse frequency of 1000-5000 Hz, a duty cycle of 30-50%, and a current density of 2-5 A / dm³. 2 The electrolyte temperature is 25-40℃, and the deposition time is 10-30 min. After deposition, rinse with deionized water 3-5 times, and then dry in a hot air environment at 80℃ for 10-15 min.

8. The method for preparing a corrosion-resistant overhead line with reduced corona loss according to claim 5, characterized in that, In step S3, the reaction temperature of the in-situ polymerization method is 0-5℃, the reaction time is 4-6h, the molar ratio of initiator to conductive polymer monomer is 1:1, and the solid content of the prepared conductive polymer emulsion is 40-50%; the high-speed dispersion speed is 2000-3000r / min, and the dispersion time is 30min; the sand milling uses 0.6-0.8mm zirconium bead media, the sand milling speed is 1500-2000r / min, the number of sand milling passes is 2-3, and the fineness of the emulsion after sand milling is ≤20μm; the bifunctional responsive microcapsules are added after sand milling, and the stirring speed during the addition process is 300-500r / min, and the stirring time is 15-20min.

9. The method for preparing a corrosion-resistant overhead line with reduced corona loss according to claim 5, characterized in that, In step S4, the parameters of the electrostatic spraying process are: spraying voltage 30-50kV, spraying distance 15-25cm, spray gun moving speed 5-10m / min, and 2-3 spraying passes; the room temperature leveling time is 10-15min.

10. The method for preparing a corrosion-resistant overhead line with reduced corona loss according to claim 5, characterized in that, In step S5, the temperature of the low-temperature hot air pre-curing is 80-120℃, the holding time is 30-60min, and the heating rate is 2-3℃ / min; the temperature of the ultrasonic-assisted curing is the same as the pre-curing temperature, the ultrasonic frequency is 20-40kHz, and the processing time is 10-20min; the low-temperature plasma surface modification treatment uses argon as the working medium, the vacuum degree is 10-30Pa, the processing power is 100-300W, and the processing time is 5-15min.

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