Weather-resistant large-section overhead insulated cable and preparation method and application thereof

Abstract

The application relates to a weather-resistant large-section overhead insulated cable and a preparation method and application thereof, and belongs to the technical field of cables. The weather-resistant large-section overhead insulated cable is sequentially provided with a steel core layer, an aluminum wire layer, a conductor shielding layer and an outer sheath layer from inside to outside; the steel core layer is at least one layer of steel wire structure, the aluminum wire layer is at least one layer of aluminum wire structure, and the material of the outer sheath layer is crosslinked polyethylene material. The weather-resistant large-section overhead insulated cable prepared by adopting the multilayer conductor layer structure has excellent electrical performance, is suitable for large-section overhead cables, the crosslinked polyethylene material of the outer sheath layer has high tensile strength, excellent elongation at break performance, good mechanical performance, can effectively resist aging, has the characteristics of high dielectric strength, can effectively insulate, and has excellent performance.

Description

Technical Field

[0001] This invention relates to a weather-resistant large-section overhead insulated cable, its preparation method and application, belonging to the field of cable technology. Background Technology

[0002] Weather-resistant, large-section overhead insulated cables achieve efficient power transmission through large-section conductors. Their special weather-resistant insulation layer ensures long service life and stability under various harsh climates, while their overhead insulation structure guarantees the safe and reliable operation of the power grid. They are an indispensable key piece of equipment for building a modern, intelligent, and robust power grid, representing an important development direction for overhead power distribution technology.

[0003] Invention patent CN120977664A discloses a mica tape cross-linked polyethylene insulated cable, which includes, from the inside out, a copper conductor, a mica tape, a cross-linked polyethylene insulation layer, a filler material, a wrapping layer, and a cable sheath. The mica tape includes mica paper, reinforcing material, and adhesive. The adhesive includes tung oil anhydride type mica glue and MgO / γ-AlO composite filler.

[0004] Invention patent CN120767041A discloses a weather-resistant, high-strength, tensile-resistant overhead insulated cable and its preparation method, including a cable conductor, a protective mechanism provided on the outside of the cable conductor, a support mechanism provided inside the protective mechanism, an outer sheath connected to the outside of the protective mechanism through a shock-absorbing mechanism, a load-bearing layer fixedly connected to the outside of the cable conductor, a repair layer provided on the outside of the load-bearing layer, a heat-insulating and fireproof layer fixedly connected to the outside of the repair layer, and a shock-absorbing mechanism including an elastic rubber layer, the inner side of which is fixedly connected to the outside of the heat-insulating and fireproof layer.

[0005] Invention patent CN117059311A discloses a high conductivity weather-resistant overhead insulated cable, comprising an aluminum alloy conductor, a conductor shielding layer extruded on the surface of the aluminum alloy conductor, and a weather-resistant XLPE insulation layer extruded on the outside of the conductor shielding layer. The aluminum alloy conductor is made of aluminum alloy rod through a wire drawing and stranding process. The raw material mass fraction composition of the aluminum alloy rod is: 0.05-0.12% Fe, 0.03-0.05% B, 0.025-0.035% Si, 0-0.012% Zn, 0-0.005% Cr, 0-0.005% Mn, 0-0.005% V, 0-0.005% Ti, 0-0.003% Cu, 0-0.003% Mg, with the balance being Al.

[0006] Invention patent CN116631675B discloses a large-section, flame-retardant, wear-resistant, and drag-resistant shielded cable for mobile applications, comprising several cable cores, a shielding layer, and an insulating protective layer. The shielding layer covers the outside of the cable cores, and the insulating protective layer covers the outside of the shielding layer. The insulating protective layer is made of insulating cable material. The preparation method of the insulating cable material includes the following steps: pretreating attapulgite clay to prepare pretreated attapulgite clay, then adding the pretreated attapulgite clay, ethanol, and purified water to a three-necked flask and stirring at room temperature for 30-50 minutes.

[0007] Invention patent CN118039239B discloses a large-section liquid-cooled high-current-carrying power cable, including a cable body and a control module for monitoring and regulating the temperature of the cable. The cable body includes, from the inside out, a conductor, a conductor shielding layer, an insulation layer, an insulation shielding layer, a semi-conductive buffer layer, a corrugated aluminum sheath, and an outer sheath.

[0008] Invention patent CN115036072B discloses a large cross-section medium-voltage longitudinal water-blocking cable and its preparation method. The cable includes, from the inside out, a conductor, a conductor shield, insulation, a non-metallic insulation shield, a metallic shielding layer, an inner sheath, and an outer sheath. The conductor is a multi-layer tightly twisted conductor, and water-blocking tape is filled between each layer of twisted conductor. The inner sheath and the outer sheath are both made of high-density polyethylene.

[0009] For weather-resistant, large-section overhead insulated cables, improving their UV resistance, insulation, and mechanical properties remains a problem that needs further development due to the different operating environments. Summary of the Invention

[0010] To address the technical problems described in the background section, this invention provides a weather-resistant, large-section overhead insulated cable, its manufacturing method, and its application. Specifically, the cable provided by this invention is a cross-linked polyethylene insulated power cable.

[0011] In one aspect, the present invention provides a weather-resistant, large-section overhead insulated cable, comprising, from the inside out, a steel core layer, an aluminum wire layer, a conductor shielding layer, and an outer sheath layer. The steel core layer comprises at least one layer of steel wire. The aluminum wire layer comprises at least one layer of aluminum wire. The outer sheath layer is made of cross-linked polyethylene.

[0012] Furthermore, the steel core layer is obtained by stranding at least two layers of steel wire.

[0013] Furthermore, the aluminum wire layer is obtained by stranding at least two layers of aluminum wire sequentially on the outer surface of the steel core layer.

[0014] Furthermore, the diameter of the steel and aluminum wires is 2.5-5mm.

[0015] This invention provides a material for the outer sheath layer of cables (cross-linked polyethylene material), which, by weight, comprises: 80-120 parts of low-density polyethylene, 15-25 parts of metallocene polyolefin, 2-8 parts of ultraviolet absorber, 4-10 parts of insulation enhancer, 3-8 parts of plasticizer, and 1.5-3.5 parts of cross-linking agent. This material for the outer sheath layer of cables is used in the preparation of the outer sheath layer of the aforementioned weather-resistant large-section overhead insulated cables.

[0016] Further, the preparation method of the ultraviolet absorber includes the following steps: (1) Mixing nano zinc oxide with KH-570 ethanol aqueous solution and acid, heating and stirring, centrifuging, washing and drying the centrifuged precipitate to obtain modified nano zinc oxide; (2) Stirring the modified nano zinc oxide with solvent, adding 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole and 2,4,6-triacryloyloxy-triazine, stirring, adding initiator to react, centrifuging, washing and drying the centrifuged precipitate to obtain the ultraviolet absorber.

[0017] Furthermore, the KH-570 ethanol aqueous solution is composed of KH-570 as a solute and an ethanol aqueous solution with a concentration of 85-95wt% as a solvent, with the KH-570 concentration being 0.5-4wt%.

[0018] Furthermore, the weight ratio of nano zinc oxide to KH-570 ethanol aqueous solution is 1:10-100.

[0019] Furthermore, the acid includes at least one of acetic acid, hydrochloric acid, and sulfuric acid.

[0020] Furthermore, the weight of the acid is 0.2-2% of the total weight of the nano zinc oxide and the KH-570 ethanol aqueous solution.

[0021] Furthermore, the heating and stirring temperature and time in step (1) are 40-65℃ and 2-10 hours.

[0022] Furthermore, the washing in step (1) is performed using ethanol.

[0023] Furthermore, the total mass of 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole, 2,4,6-triacryloyloxy-triazine, and the weight ratio of modified nano zinc oxide is 0.8-1:1.

[0024] Furthermore, the weight ratio of 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole to 2,4,6-triacryloyloxy-triazine is 8-10:1.

[0025] Furthermore, the initiator is benzoyl peroxide, and the amount added is 0.8-1.5% of the weight of the modified nano zinc oxide.

[0026] Furthermore, the temperature and time of the reaction in step (2) are 70-85℃ and 4-10 hours.

[0027] Furthermore, in step (2), toluene is used for washing.

[0028] Furthermore, the preparation method of the insulation enhancer includes the following steps: (I) Take nano-hexagonal boron nitride and stir and mix with isopropanol aqueous solution to obtain a mixture; (II) Add heptadecafluorodecyltrimethoxysilane and acid to the mixture, heat and stir to react, cool, centrifuge, wash and dry the centrifuged precipitate to obtain the insulation enhancer.

[0029] Furthermore, the concentration of isopropanol in the isopropanol aqueous solution is 85-95 wt%.

[0030] Furthermore, the weight ratio of nano-hexagonal boron nitride to isopropanol aqueous solution is 1:10-100.

[0031] Furthermore, the weight ratio of nano-hexagonal boron nitride to heptadecafluorodecyltrimethoxysilane is 1:1.5-3.

[0032] Furthermore, the acid includes at least one of acetic acid, hydrochloric acid, and sulfuric acid.

[0033] Furthermore, the weight of the acid is 0.2-2% of the weight of the mixture in step (I).

[0034] Furthermore, the conditions for heating and stirring the reaction in step (II) are: temperature 65-75℃ and time 8-15 hours.

[0035] Furthermore, in step (II), the washing process uses ethanol.

[0036] Furthermore, the plasticizer includes at least one of trioctyl trimellitate and isooctyl epoxide. Metallocene polyolefins include metallocene polyethylene.

[0037] Furthermore, the crosslinking agent includes at least one of dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and 1,3-bis(tert-butylperoxyisopropyl)benzene.

[0038] Furthermore, the preparation method of the above-mentioned outer sheath material includes: heating and mixing low-density polyethylene, metallocene polyolefin, ultraviolet absorber, insulation enhancer and plasticizer in a high-speed mixer, cooling and adding crosslinking agent to mix, then feeding the mixture into a twin-screw extruder for extrusion, and crosslinking and curing after extrusion to obtain the outer sheath material (i.e. crosslinked polyethylene).

[0039] The present invention also provides a method for preparing the above-mentioned weather-resistant large-section overhead insulated cable, comprising the following steps: Step A: Install at least one layer of steel wire structure as the steel core layer; Step B: Set at least one layer of aluminum wire structure as an aluminum wire layer on the surface of the steel core layer; Step C: Set a conductor shielding layer on the surface of the aluminum wire layer; Step D: Coat the surface of the conductor shielding layer with cross-linked polyethylene material to form an outer sheath layer, thus obtaining a weather-resistant large-section overhead insulated cable.

[0040] The present invention also provides the application of the aforementioned weather-resistant large-section overhead insulated cable in power transmission.

[0041] The beneficial technical effects of the present invention are as follows: The weather-resistant large-section overhead insulated cable of the present invention comprises, from the inside out, a steel core layer, an aluminum wire layer, a conductor shielding layer, and an outer sheath layer. The steel core layer consists of at least one layer of steel wire, the aluminum wire layer consists of at least one layer of aluminum wire, and the outer sheath layer is made of cross-linked polyethylene. The multi-layer conductor structure of the present invention provides excellent conductivity and is suitable for large-section overhead cables. Furthermore, the cross-linked polyethylene material of the outer sheath layer prepared by the present invention exhibits high tensile strength, excellent elongation at break, good mechanical properties, effective aging resistance, and high dielectric strength, providing effective insulation. This results in a weather-resistant large-section overhead insulated cable with superior performance.

[0042] This invention utilizes nano-zinc oxide as a base to construct a long-lasting "core-shell" structure for UV absorption. The hydroxyl groups on the surface of the nano-zinc oxide undergo a hydrolysis-condensation reaction with the methoxy groups of the silane coupling agent KH-570, firmly grafting active carbon-carbon double bonds onto the surface of the inorganic ZnO nanoparticles. This provides an "anchor point" for subsequent grafting, serving as a bridge. Then, under the initiation of benzoyl peroxide, the organic UV-absorbing monomers 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole, 2,4,6-triacryloyloxy-triazine, and KH-570 undergo copolymerization, further grafting UV-absorbing active ingredients onto the surface of the nano-zinc oxide. Simultaneously, this increases the compatibility of the nano-zinc oxide with resin raw materials such as polyethylene, improving the mechanical properties and weather resistance of the outer sheath material.

[0043] Furthermore, this invention selects nano-hexagonal boron nitride with excellent insulation properties as raw material, and uses heptadecafluorodecyltrimethoxysilane hydrolysis-condensation to improve the dispersibility of nano-hexagonal boron nitride in the outer sheath material, thereby enhancing the insulation and mechanical properties of the outer sheath material.

[0044] The cross-linked polyethylene insulated and weather-resistant power cable prepared by this invention has high tensile strength and excellent elongation at break of the outer sheath material, good mechanical properties, and effective aging resistance. It also has high dielectric strength and effective insulation, which makes the prepared weather-resistant large cross-section overhead insulated cable have good performance. Attached Figure Description

[0045] Figure 1 : Schematic diagram of the weather-resistant large-section overhead insulated cable 1 of the present invention. Detailed Implementation

[0046] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0047] Low-density polyethylene: LDPE (low-density polyethylene) D024 / Shanghai Petrochemical. Metallocene polyolefin: Metallocene polyethylene, Exceed™ 4536PA Wire & Cable, ExxonMobil Chemical.

[0048] I. Preparation of the outer sheath material (cross-linked polyethylene) Material 1: Raw material composition, by weight: 110 parts low-density polyethylene, 20 parts metallocene polyolefin, 6.5 parts ultraviolet absorber, 7.5 parts insulation enhancer, 6.5 parts plasticizer, and 2 parts crosslinking agent. Plasticizer: Isooctyl epoxide. Crosslinking agent: Diisopropylbenzene peroxide.

[0049] The preparation method of ultraviolet absorber is as follows: (1) Mix nano zinc oxide with KH-570 ethanol aqueous solution and glacial acetic acid, heat to 50°C and stir for 6 hours, centrifuge, wash the centrifuged precipitate with anhydrous ethanol and dry to constant weight at 60°C to obtain modified nano zinc oxide. The KH-570 ethanol aqueous solution is composed of KH-570 and a 92wt% ethanol aqueous solution, with a KH-570 concentration of 2wt%. The weight ratio of nano-zinc oxide to the KH-570 ethanol aqueous solution is 1:20. The weight of glacial acetic acid is 1.05% of the total weight of nano-zinc oxide and the KH-570 ethanol aqueous solution. (2) Modified nano zinc oxide and solvent toluene were mixed at 50°C for 22 minutes at a weight ratio of 1:35. 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole and 2,4,6-triacryloyloxy-triazine were added and stirred at room temperature for 5 minutes. Benzoyl peroxide was added and the mixture was heated to 75°C and stirred for 6.5 hours. The mixture was centrifuged and the precipitate was washed with toluene and dried at 60°C to constant weight to obtain the ultraviolet absorber. The weight ratio of the total mass of 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole and 2,4,6-triacryloyloxy-triazine to modified nano zinc oxide is 0.85:1; the weight ratio of 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole to 2,4,6-triacryloyloxy-triazine is 9:1; and the amount of benzoyl peroxide added is 1.1% of the weight of modified nano zinc oxide.

[0050] The insulation enhancer is prepared by the following method: (I) Nano-hexagonal boron nitride and 90wt% isopropanol aqueous solution are mixed at a weight ratio of 1:20 at 50℃ for 50 minutes to obtain a mixture; (II) Heptadecafluorodecyltrimethoxysilane and glacial acetic acid are added to the mixture, heated to 70℃ and stirred for 10 hours, cooled to room temperature, centrifuged, the centrifuged precipitate is washed with anhydrous ethanol, and dried at 60℃ to constant weight to obtain the insulation enhancer; The weight ratio of nano-hexagonal boron nitride and heptadecanofluorodecyltrimethoxysilane is 1:2, and the weight of glacial acetic acid is 1.2% of the weight of the mixture in step (I).

[0051] The preparation method of Material 1 is as follows: Low-density polyethylene, metallocene polyolefin, ultraviolet absorber, insulation enhancer and plasticizer are mixed in a high-speed mixer at 100℃ and 600rpm for 20 minutes. Cooling water is turned on and the speed is kept constant to cool to 45℃. Crosslinking agent is added and mixed at 600rpm for 10 minutes. Then the mixture is fed into a twin-screw extruder for extrusion. The temperature from the feeding section to the discharge section is set to 145℃, 155℃, 165℃, 175℃, 175℃ and 165℃, and the main screw speed is 20rpm. The extruded material is crosslinked at 185℃ for 15 minutes, at 190℃ for 10 minutes and at 195℃ for 10 minutes under a nitrogen atmosphere. After cooling to room temperature, Material 1 is obtained.

[0052] Material 2: Raw material composition, by weight: 101 parts low-density polyethylene, 19 parts metallocene polyolefin, 5.9 parts ultraviolet absorber, 6.8 parts insulation enhancer, 5.8 parts plasticizer, and 1.82 parts crosslinking agent. Plasticizer: Isooctyl epoxide. Crosslinking agent: Diisopropylbenzene peroxide.

[0053] The preparation method of ultraviolet absorber is as follows: (1) Mix nano zinc oxide with KH-570 ethanol aqueous solution and glacial acetic acid, heat to 45°C and stir for 5.5 hours, centrifuge, wash the centrifuged precipitate with anhydrous ethanol and dry at 60°C to constant weight to obtain modified nano zinc oxide; The KH-570 ethanol aqueous solution is composed of KH-570 and a 90wt% ethanol aqueous solution, with a KH-570 concentration of 1.9wt%. The weight ratio of nano-zinc oxide to the KH-570 ethanol aqueous solution is 1:20. The weight of glacial acetic acid is 1% of the total weight of nano-zinc oxide and the KH-570 ethanol aqueous solution. (2) Modified nano zinc oxide and solvent toluene were mixed at 55°C for 25 minutes at a weight ratio of 1:37. 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole and 2,4,6-triacryloyloxy-triazine were added and stirred at room temperature for 4 minutes. Benzoyl peroxide was added and the mixture was heated to 80°C and stirred for 6 hours. The mixture was centrifuged and the precipitate was washed with toluene and dried at 60°C to constant weight to obtain the ultraviolet absorber. The total mass of 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole, 2,4,6-triacryloyloxy-triazine, and the weight ratio of modified nano zinc oxide were 0.95:1; the weight ratio of 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole, 2,4,6-triacryloyloxy-triazine was 8:1; and the amount of benzoyl peroxide added was 1.05% of the weight of modified nano zinc oxide.

[0054] The insulation enhancer is prepared by: (I) mixing nano-hexagonal boron nitride with a 95wt% isopropanol aqueous solution at a weight ratio of 1:20 at 55°C for 40 minutes to obtain a mixture; (II) adding heptadecafluorodecyltrimethoxysilane and glacial acetic acid to the mixture, heating to 75°C and stirring for 9 hours, cooling to room temperature, centrifuging, washing the centrifuged precipitate with anhydrous ethanol, and drying at 60°C to constant weight to obtain the insulation enhancer; The weight ratio of nano-hexagonal boron nitride and heptadecanofluorodecyltrimethoxysilane is 1:1.8, and the weight of glacial acetic acid is 1.35% of the weight of the mixture in step (I).

[0055] The preparation method of Material 2 is as follows: Low-density polyethylene, metallocene polyolefin, ultraviolet absorber, insulation enhancer and plasticizer are mixed in a high-speed mixer at 100℃ and 600rpm for 20 minutes. Cooling water is turned on and the speed is kept constant to cool to 45℃. Crosslinking agent is added and mixed at 600rpm for 10 minutes. Then the mixture is fed into a twin-screw extruder for extrusion. The temperature from the feeding section to the discharge section is set to 145℃, 155℃, 165℃, 175℃, 175℃ and 165℃, and the main screw speed is 20rpm. The extruded material is crosslinked at 185℃ for 15 minutes, at 190℃ for 10 minutes and at 195℃ for 10 minutes under a nitrogen atmosphere. After cooling to room temperature, Material 2 is obtained.

[0056] Material 3: The difference from Material 1 is that KH-570 in the preparation method of ultraviolet absorber is replaced with an equimolar amount of γ-aminopropyltriethoxysilane, otherwise the same.

[0057] Material 4: The difference from Material 1 is that it uses the same weight of modified nano zinc oxide as the UV absorber as Material 1, otherwise it is the same.

[0058] Material 5: The difference from Material 1 is that 2,4,6-triacryloyloxy-triazine in the preparation method of the ultraviolet absorber is omitted; otherwise, they are the same.

[0059] Material 6 differs from Material 1 in that the weight ratio of 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole and 2,4,6-triacryloyloxy-triazine is 2:1, while the others are the same.

[0060] Material 7 differs from Material 1 in that the weight ratio of 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole and 2,4,6-triacryloyloxy-triazine is 25:1, while the others are the same.

[0061] Material 8: The difference from Material 1 is that it uses 7.5 parts by weight of nano-hexagonal boron nitride as an insulation enhancer, otherwise it is the same.

[0062] Material 9 differs from Material 1 in that it uses an equimolar amount of γ-aminopropyltriethoxysilane instead of heptadecafluorodecyltrimethoxysilane; otherwise, they are the same.

[0063] II. Testing of Outer Sheath Material According to the method described in national standard GB / T 14049-2008, the tensile strength and elongation at break of the above materials 1-9 were tested. Ultraviolet light irradiation (0-1008h) was used to test the tensile strength and elongation at break after light aging. The change rate of tensile strength and the decrease rate of elongation at break of each material after aging were calculated. The results are shown in Table 1-2.

[0064] Table 1: Tensile Strength

[0065] Table 2: Elongation at Break

[0066] The dielectric strength of materials 1-2 and 8-9 were tested according to the method described in the national standard GB / T 14049-2008, and the results are shown in Table 3.

[0067] Table 3: Dielectric Strength

[0068] Based on the test results in Tables 1-3, it can be seen that the outer sheath material prepared by this invention has high tensile strength, excellent elongation at break, and high dielectric strength. After photoaging by ultraviolet light irradiation, the hardness and elongation at break change little, the performance after aging is still relatively good, the mechanical properties are well retained, and it has excellent weather resistance.

[0069] In Material 3, reactive γ-aminopropyltriethoxysilane is not used to prepare UV absorbers. 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole and 2,4,6-triacryloyloxy-triazine cannot be effectively grafted onto the nano-oxidative surface, and cannot effectively enhance the aging resistance of the material. After aging tests, the strength and flexibility of the material decrease.

[0070] Material 4 uses only nano zinc oxide, whose surface is not modified by KH-570, and does not have 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole or 2,4,6-triacryloyloxy-triazine grafted onto the surface of nano zinc oxide. The nano zinc oxide has poor compatibility with resin materials, low material hardness and elongation at break, and significantly reduced aging resistance.

[0071] Material 5 does not use the multifunctional 2,4,6-triacryloyloxy-triazine, resulting in low compatibility efficiency between the UV absorber and the resin matrix, reduced strength and elongation at break, and decreased aging resistance.

[0072] In materials 6 and 7, the proportions of monofunctional and polyfunctional 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole and 2,4,6-triacryloyloxy-triazine in the monomers reacted in the UV absorber changed, resulting in changes in tensile strength and elongation at break before and after aging.

[0073] The boron nitride in material 8 is not modified with organic compounds, and the boron nitride in material 9 is modified with non-fluorinated siloxanes. The strength and elongation at break of the prepared materials are different from those of material 1, and the overall performance is weaker than that of material 1.

[0074] III. Preparation of Weather-Resistant Large-Cross-Section Overhead Insulated Cables Cable 1: Its preparation method is as follows: Step A: Set a 3mm diameter steel wire as the center line, and twist a 3mm diameter steel wire around the center line to obtain a second layer of steel wire structure. The two layers of steel wire structure form the steel core layer. Step B: Strand a layer of aluminum wire with a diameter of 3mm onto the surface of the steel core layer, and then strand another layer of aluminum wire with a diameter of 3mm onto the surface of the aluminum wire. The two layers of aluminum wire structure constitute the aluminum wire layer. Step C: A conductor shielding layer is set on the outer surface of the aluminum wire layer; Step D: Coat the surface of the conductor shielding layer with cross-linked polyethylene material (material 1) to form an outer sheath layer, thereby obtaining a weather-resistant large-section overhead insulated cable.

[0075] A structural schematic diagram of cable 1 is attached. Figure 1 .

[0076] Cable 2: Its preparation method is as follows: Step A: Set a 3mm diameter steel wire as the center line, and twist a 3mm diameter steel wire around the center line to obtain a second layer of steel wire structure. The two layers of steel wire structure form the steel core layer. Step B: Strand a layer of aluminum wire with a diameter of 3mm onto the surface of the steel core layer, and then strand another layer of aluminum wire with a diameter of 3mm onto the surface of the aluminum wire. The two layers of aluminum wire structure constitute the aluminum wire layer. Step C: A conductor shielding layer is set on the outer surface of the aluminum wire layer; Step D: The cross-linked polyethylene material (material 2) is wrapped around the surface of the conductor shielding layer to form an outer sheath layer, resulting in a weather-resistant large-section overhead insulated cable.

[0077] Cable 3: Its preparation method is as follows: Step A: Set a 3mm diameter steel wire as the center line, and twist a 3mm diameter steel wire around the center line to obtain a second layer of steel wire structure. The two layers of steel wire structure form the steel core layer. Step B: A layer of aluminum wire with a diameter of 3mm is stranded on the surface of the steel core layer, then another layer of aluminum wire with a diameter of 3mm is stranded on the surface of the aluminum wire, and then another layer of aluminum wire with a diameter of 3mm is stranded on the surface of the aluminum wire. The three-layer aluminum wire structure constitutes the aluminum wire layer. Step C: A conductor shielding layer is set on the outer surface of the aluminum wire layer; Step D: Coat the surface of the conductor shielding layer with cross-linked polyethylene material (material 1) to form an outer sheath layer, thereby obtaining a weather-resistant large-section overhead insulated cable.

[0078] The technical solutions provided by the present invention have been described in detail above. For those skilled in the art, there will be changes in specific implementation methods and application scope based on the ideas of the embodiments of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A weather-resistant, large-section overhead insulated cable, characterized in that, The structure consists of a steel core layer, an aluminum wire layer, a conductor shielding layer, and an outer sheath layer, arranged sequentially from the inside out. The steel core layer is at least one layer of steel wire structure, the aluminum wire layer is at least one layer of aluminum wire structure, and the outer sheath layer is made of cross-linked polyethylene. The raw materials for preparing cross-linked polyethylene materials are: 80-120 parts of low-density polyethylene, 15-25 parts of metallocene polyolefin, 2-8 parts of ultraviolet absorber, 4-10 parts of insulation enhancer, 3-8 parts of plasticizer, and 1.5-3.5 parts of cross-linking agent; The preparation method of ultraviolet absorber includes the following steps: (1) Mix nano zinc oxide with KH-570 ethanol aqueous solution and acid, heat and stir, centrifuge, and wash and dry the centrifuged precipitate to obtain modified nano zinc oxide; (2) Stir the modified nano zinc oxide with solvent, add 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole and 2,4,6-triacryloyloxy-triazine, stir, add initiator to react, centrifuge, and wash and dry the centrifuged precipitate to obtain ultraviolet absorber; The preparation method of the insulation enhancer includes the following steps: (I) Take nano-hexagonal boron nitride and stir and mix with isopropanol aqueous solution to obtain a mixture; (II) Add heptadecafluorodecyltrimethoxysilane and acid to the mixture, heat and stir to react, cool, centrifuge, wash and dry the centrifuged precipitate to obtain the insulation enhancer; The weight ratio of 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole to 2,4,6-triacryloyloxy-triazine is 8-10:

1.

2. The weather-resistant large-section overhead insulated cable according to claim 1, characterized in that, The steel core layer is made of at least two layers of steel wire twisted together.

3. The weather-resistant large-section overhead insulated cable according to claim 1, characterized in that, The aluminum wire layer is formed by twisting at least two layers of aluminum wire sequentially on the outer surface of the steel core layer.

4. The weather-resistant large-section overhead insulated cable according to claim 1, characterized in that, The diameter of the steel and aluminum wires is 2.5-5mm.

5. A weather-resistant large-section overhead insulated cable according to claim 1, characterized in that, The total mass of 2-(2'-hydroxy-5'-methacryloyloxyphenyl)benzotriazole, 2,4,6-triacryloyloxy-triazine, and the weight ratio of modified nano zinc oxide were 0.8-1:

1. And / or, the weight ratio of nano-hexagonal boron nitride and heptadecafluorodecyltrimethoxysilane is 1:1.5-3.

6. A method for preparing a weather-resistant large-section overhead insulated cable according to any one of claims 1-5, characterized in that, The steps include the following: Step A: Install at least one layer of steel wire structure as the steel core layer; Step B: Deposit at least one layer of aluminum wire structure as an aluminum wire layer on the surface of the steel core layer; Step C: Set a conductor shielding layer on the surface of the aluminum wire layer; Step D: Coat the surface of the conductor shielding layer with cross-linked polyethylene material to form an outer sheath layer, thus obtaining a weather-resistant large-section overhead insulated cable.

7. The application of a weather-resistant large-section overhead insulated cable according to any one of claims 1-5 in power transmission.

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