Tensile-resistant environment-friendly and energy-saving cable and preparation method thereof

Abstract

The application discloses an anti-stretching environment-friendly energy-saving cable and a preparation method thereof. The anti-stretching environment-friendly energy-saving cable comprises, from inside to outside, a cable core, a winding shielding layer, an insulation layer and a sheath. The cable core is twisted by a plurality of independent wire cores. The wire core comprises, from inside to outside, an aluminum core, a copper sheath, a modified BN lubricating layer and an insulation sheath. Adjacent wire cores are filled with a paraffin-based filler. The application replaces the existing pure copper or pure aluminum conductor with a copper-clad aluminum structure to achieve a balance between high conductivity and light weight. The silicon-hydrogen addition reaction occurs between the vinyl-modified BN and the hydrogen-containing silicone oil and silica gel of the insulation sheath to form a chemically anchored interface-enhanced BN lubricating structure with enhanced and heat-conducting functions, thereby avoiding powder falling off and BN layer sliding compensation for metal / silica gel deformation difference during dragging. The expansion graphite is introduced to absorb paraffin, thereby absorbing deformation heat energy and reducing plastic deformation. The aramid rope ring is pre-embedded, and the XLPE sheath is vulcanized to enhance the tensile strength and aging resistance.

Description

Technical Field

[0001] This invention relates to the field of energy-saving cable technology applicable to high-frequency power transmission conditions, and particularly to a tensile-resistant, environmentally friendly, and energy-saving cable and its preparation method. Background Technology

[0002] Energy-saving cables refer to special cables that use low-resistivity conductor cores and are suitable for high-load, long-distance, and long-term operation scenarios. Their conductors are mostly made of high-purity oxygen-free copper (copper content ≥99.99%) or rare earth high-iron aluminum alloy (rare earth elements are added to optimize conductivity). They can cope with the loss of high-frequency AC power, and the line loss rate is generally below 3%. Especially in industrial high-current and power grid trunk line scenarios, the annual power saving effect is significant.

[0003] However, existing energy-saving cables still have the following shortcomings:

[0004] 1) Pure copper conductors are expensive and have a high density (8.96 g / cm³), while pure aluminum conductors are lightweight (density 2.7 g / cm³). If pure aluminum is used as a substitute, the resistivity at high frequencies (≥30Hz) is high (measured to be 165% of that of pure copper cables) and the mechanical strength is insufficient (the tensile strength of aluminum is only 80 MPa, and it is prone to deformation and breakage when dragged and laid).

[0005] 2) The thermal expansion coefficients of the metallic conductor and the insulating layer differ greatly (aluminum: 23×10). -6 / ℃; Silicone: 250×10 -6 / ℃), when bent or stretched, interfacial shear stress causes delamination, leading to partial discharge (breakdown), lubricant shedding (increased friction loss), and thermo-mechanical coupling failure (causing plastic deformation of the insulation layer and filler migration and bulging). Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by proposing a tensile-resistant, environmentally friendly, and energy-saving cable and its preparation method.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In the first aspect, this application provides a tensile-resistant, environmentally friendly, and energy-saving cable, which includes, from the inside out, a cable core, a winding shielding layer, an insulation layer, and a sheath. The cable core is made of multiple independent wire cores twisted together. The wire core includes, from the inside out, an aluminum core, a copper sheath, a modified BN lubricating layer, and an insulation layer. Paraffin-based filler is filled between adjacent wire cores.

[0009] The aluminum core is a lightweight conductor, reducing cost and energy consumption.

[0010] The outer layer of the copper cladding is nickel-plated to avoid negative reactions such as high-temperature oxidation or other corrosion of the copper during the extrusion process. The thickness of the copper cladding is 15-25% of the radius of the aluminum core, used to form a highly conductive pure copper layer. Under AC power at power frequencies (50Hz / 60Hz) or higher, the skin effect causes the current to flow mainly in the outer copper layer. As long as the copper layer thickness is greater than or equal to the penetration depth δ at that frequency, most of the current will be confined within the copper layer. For example, at a power frequency of 50Hz, the penetration depth of pure copper δ≈9.3mm. For cables with relatively small diameters (e.g., <35mm), this is sufficient. 2 A reasonably designed copper layer thickness (such as 0.2mm-0.5mm) is sufficient to carry most power frequency AC current, and the copper-clad aluminum core can improve conductivity and oxidation resistance.

[0011] The low-density, low-cost aluminum core mainly serves as a mechanical support and conducts DC or very low-frequency current. In DC conditions (such as photovoltaic or wind power), it helps to share the conductivity of copper. In AC conditions, due to the skin effect, the current contribution of the aluminum core is very small.

[0012] Under AC conditions, the effective conductive portion of a copper-clad aluminum conductor is approximately equal to the cross-sectional area of ​​the copper layer. Clad in an aluminum core, it can improve conductivity and oxidation resistance. Although the conductivity of aluminum is only about 61% of that of copper, since the current rarely penetrates into the aluminum core, the overall AC resistance mainly depends on the thickness and conductivity of the copper layer, rather than the average conductivity of the entire cross-section.

[0013] Compared to solid aluminum conductors, copper layers provide highly conductive surface paths, significantly reducing the additional resistance increment caused by the skin effect (the portion where AC resistance > DC resistance), thus reducing skin effect losses; in addition, copper has higher tensile strength than aluminum, which can significantly improve the tensile performance of aluminum cable cores without significantly reducing costs or conductivity.

[0014] The modified BN lubricating layer is composed of vinyl-modified BN and vinyl polydimethylsiloxane (Vi-PDMS, molecular weight 20000-25000, vinyl content 2.5-3.0 mol%, viscosity 8000-1000 mPa·s viscous liquid) in a weight ratio of 1.8-2.3:1. It is then co-cured with silicone to form a fixed thin-layer lubricating structure between the modified BN lubricating layer and the insulating skin.

[0015] The synthesis steps of the vinyl-modified BN are as follows:

[0016] S01. Disperse h-BN in concentrated nitric acid aqueous solution to perform BN hydroxylation pretreatment, obtaining hydroxylated BN with a hydroxyl group density of 12-15 hydroxyl groups / nm. 2 ;

[0017] S02. KH-570 was activated by silane hydrolysis using anhydrous toluene, deionized water, and triethylamine to obtain a hydrolyzed silane solution.

[0018] S03. A silane grafting reaction was carried out using hydroxylated BN and hydrolyzed silane solution to obtain a reaction solution;

[0019] S04. The reaction solution is post-treated and purified to obtain vinyl-modified BN.

[0020] Preferably, step S01 (BN hydroxylation pretreatment) specifically includes:

[0021] 20 g of h-BN (flake diameter 1-5 μm, thickness ≤100 nm) was dispersed in 200 ml of 65% concentrated nitric acid aqueous solution, refluxed at 80 °C for 6 hours, centrifuged, washed with deionized water until neutral (pH=7), and vacuum dried (120 °C, 4 h) to obtain hydroxylated BN (i.e., HO-BN) with a hydroxyl density of 12-15 hydroxyl groups / nm. 2 ;

[0022] Step S02 (silane hydrolysis activation) specifically includes:

[0023] Under dry nitrogen protection, 5g of KH-570 (γ-methacryloyloxypropyltrimethoxysilane) was dissolved in 100ml of anhydrous toluene; 0.5ml of deionized water was added dropwise (molar ratio KH-570:H2O = 1:1.2), and the mixture was stirred for 30min; 0.1g of triethylamine (TEA) was added, and the mixture was reacted at 40℃ for 2h to obtain a hydrolyzed silane solution.

[0024] The hydrolysis reaction formula is as follows:

[0025]

[0026] Step S03 (silane grafting reaction) specifically includes:

[0027] Under nitrogen protection, 10g of hydroxylated BN was added to a hydrolyzed silane solution and ultrasonically dispersed for 30min (300W). The temperature was raised to 110℃ and refluxed for 8h to obtain the reaction solution. The methanol content in toluene was measured every 2h (GC monitoring). The reaction endpoint was defined as methanol release > 95% of the theoretical value.

[0028] Step S03 (post-processing and purification) specifically includes:

[0029] The reaction solution was cooled to room temperature and centrifuged (8000 rpm, 10 min) to collect the solid. It was then ultrasonically washed three times with toluene and ethanol to remove physically adsorbed silane. The solid was then vacuum dried at 60 °C for 12 h to obtain vinyl-modified BN (Vi-BN).

[0030] Preferably, the insulating layer is made of silicone, and the insulating layer is prepared from the following raw materials:

[0031] 10 kg vinylsiloxane raw rubber, 0.4-0.5 kg polyvinylsiloxane raw rubber, 1.2-1.5 kg hydrogen-containing silicone oil, 0.1-0.15 kg platinum(0)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane (Castel catalysis, promoting the cross-linking of active hydrogen in hydrogen-containing silicone oil with vinyl groups) and 1-5 g 1-ethynylcyclohexanol (inhibitor, preventing premature local cross-linking into gel).

[0032] Preferably, the winding shielding layer is made of conductive PI tape spirally wrapped, which takes into account electromagnetic shielding, high temperature resistance and flexibility.

[0033] Preferably, the insulation layer is made of PVC rubber, which has a low cost, and aramid ropes are distributed in a ring inside the insulation layer to further improve tensile strength and resistance to large deformation of the cable core.

[0034] Preferably, the sheath is made of cross-linked polyethylene (XLPE), an environmentally friendly material with high weather resistance, aging resistance, and mechanical strength.

[0035] Preferably, the paraffin-based filler is composed of paraffin (melted at 55-65℃, absorbing heat), expanded graphite (pore size 100-300μm), and nano-alumina (particle size 15-60nm) mixed in a weight ratio of 10:1-2:1-2.

[0036] Preferably, the raw material of the insulating layer includes:

[0037] Vinyl siloxane raw rubber is a long-chain polysiloxane with vinyl short links at both ends of its macromolecular chain. It is in the form of solid raw rubber with a molecular weight of 300,000-400,000 and a vinyl content of 0.02-0.03 mmol vinyl / g vinyl siloxane raw rubber.

[0038] Polyvinylsiloxane raw rubber is a long-chain polysiloxane with vinyl short links at both ends or on the side chains of its macromolecular chain. It is in the form of solid raw rubber, with a molecular weight of 300,000-400,000 and a vinyl content of 2-3 mmol vinyl / g.

[0039] Hydrogen-containing silicone oil is a polydimethyl silicone oil with Si-H bonds and a hydrogen content of 4-6 mmol / g.

[0040] Modified BN lubricating layer: Located between the copper cladding and the insulating layer, it is prepared by reacting hydroxylated BN with a vinyl-containing silane.

[0041] Insulation layer: made of silicone rubber, vulcanized at 200℃, which crosslinks polysiloxane, hydrogen-containing silicone oil and modified BN to form a reinforced interface.

[0042] Secondly, the present invention also proposes a method for preparing the aforementioned tensile-resistant, environmentally friendly, and energy-saving cable, comprising the following steps:

[0043] S1. Preparing single-strand wire cores, specifically including:

[0044] S101, Aluminum Core Processing

[0045] The electrical grade aluminum rod is drawn to the designed diameter (e.g., 2.5-6mm), cut into fixed lengths of aluminum wire, and the surface is polished to remove the oxide layer, thus obtaining the aluminum core.

[0046] S102, copper cladding and nickel plating

[0047] A continuous extrusion coating process is used to form a copper cladding around the aluminum core, with the copper layer thickness controlled at 15-25% of the aluminum core radius (e.g., 0.2-0.5 mm). A nickel layer (thickness ≥ 1 μm) is electroplated on the outer surface of the copper cladding to prevent high-temperature oxidation.

[0048] S103, coated with modified BN lubricating layer

[0049] Vinyl modified BN and vinyl polydimethylsiloxane are mixed at a weight ratio of 1.8-2.3:1 and stirred into a uniform slurry. The slurry is then applied to the surface of the copper cladding by dip coating or spraying to form a thin layer (5-10 μm thick). The slurry is pre-cured at 80°C for 5 min to obtain the modified BN lubricating layer.

[0050] S104, extrusion and vulcanization

[0051] The insulating material is mixed and kneaded at 40-50℃ to form an extrusion material, which is then extruded onto the modified BN lubricating layer. It is then pre-cured at 120-130℃ for 10 minutes to allow the hydrogen-containing silicone oil to penetrate into the BN layer for cross-linking. Finally, it is infrared-cured at 200±5℃ for 20 minutes to form a silicone / BN reinforced structure, thus obtaining a single-strand wire core.

[0052] The mixture is compounded at 40-50℃ to form an extrusion material, which is then extruded onto the modified BN lubricating layer at 30-40℃. Pre-curing is then performed at 120-130℃ to allow the hydrogen-containing silicone oil to penetrate into the modified BN lubricating layer and cross-link with the vinyl-modified BN and vinyl polydimethylsiloxane. Finally, infrared curing is performed at 200±5℃ to obtain an insulating skin. This results in a silicone / BN reinforced thin-layer structure where the vinyl-modified BN and silicone network are connected, preventing powder from falling off during lubrication and causing uneven lubrication. The stability of the lubrication layer is particularly important during dragging, stretching, or bending processes, where the deformation of the silicone and metal core differs.

[0053] S2, Cable core stranding

[0054] The raw material of paraffin-based filler is heated to 60℃ to become a paste, which is coated on the outside of the wire core (thickness is 3-5μm). Then, multiple single-strand wire cores are bundled together in a concentric twisting manner, with the twisting pitch ≤ 15 times the outer diameter of the cable core. After the twisted cable core bundle is rounded through a cylindrical through hole, it is cooled to obtain a paraffin-coated cable core.

[0055] S3, Shielding layer wrapping treatment

[0056] Outside the paraffin-coated cable core, conductive polyimide tape (50cm wide, with an overlap rate of 40-60%) is spirally wrapped to form a tape shielding layer.

[0057] S4, Extruded insulation layer

[0058] PVC rubber is extruded over the shielding layer to form an insulating layer. Aramid ropes are pre-placed in the die of the extruder and are evenly distributed in a ring inside the insulating layer (spaced 2-3mm). The extrusion temperature is 160-180℃, and the material is cooled and shaped.

[0059] S5, Sheath Molding

[0060] Cross-linked polyethylene (XLPE) is extruded over the insulation layer at a temperature of 120-140℃ (to avoid high temperature damage to the aramid rope), and then vulcanized at 180℃ for 30 minutes using infrared technology to obtain the sheath.

[0061] S6, Post-processing

[0062] The sheath obtained from S5 is cooled to room temperature in a water-cooling tank, and then wound up under tension control (to prevent deformation). Irregular sections at the ends are cut off to obtain the energy-saving cable product.

[0063] Performance testing

[0064] Tensile strength test (≥150% of design load).

[0065] Conductivity test (50Hz AC resistance ≤ 110% of pure copper cable of the same specification).

[0066] High voltage insulation test (no breakdown at power frequency 3.5kV / 5min).

[0067] Compared with the prior art, the beneficial effects of the present invention are:

[0068] 1. This invention achieves a balance between high conductivity and lightweight by replacing existing pure copper or pure aluminum conductors with a copper-clad aluminum structure. The amount of copper used is reduced by at least 70%, and the cost is reduced by at least 30%. At the same time, the high-frequency resistivity is only about 8% higher than that of pure copper conductors. Furthermore, by precisely controlling the thickness of the copper layer (15-25% of the aluminum core radius), it is ensured that 98% of the current within the skin depth is conducted by the copper layer. The copper layer strength ≥200 MPa can compensate for the weaknesses of the aluminum core, and the tensile strength is increased by 120% compared to pure aluminum cable. The aluminum core is 30% lighter, reducing energy consumption during transportation and installation.

[0069] 2. This invention pre-crosslinks vinyl-modified BN with vinyl polydimethylsiloxane (Vi-PDMS), and then uses hydrogen-containing silicone oil to undergo a hydrosilylation reaction with the insulating silicone layer to form a BN-silicone interpenetrating network. This forms a chemically anchored, reinforcing, and thermally conductive interface-reinforced BN lubricating structure, which prevents powder from falling off during dragging and compensates for metal / silicone deformation due to BN layer slippage. The breakdown voltage is >5.0 kV.

[0070] 3. This invention introduces expanded graphite to adsorb paraffin and provides alumina reinforcement with high thermal conductivity. The resulting paraffin-based filler utilizes the heat energy of deformation absorbed by the melting of paraffin at 55-65℃ to reduce plastic deformation. Furthermore, nano-Al2O3 is used to fill the gaps, accelerating heat diffusion and suppressing conductor temperature rise.

[0071] 4. The present invention also significantly improves tensile strength and aging resistance by pre-embedding aramid rope in a ring and reinforcing with XLPE sheath vulcanization. Attached Figure Description

[0072] Figure 1 This is a structural schematic diagram of a tensile-resistant, environmentally friendly, and energy-saving cable proposed in this invention.

[0073] In the diagram: Cable core 1, wire core 101, aluminum core 101A, copper sheath 101B, modified BN lubricating layer 101C, insulation sheath 101D, winding shielding layer 2, insulation layer 3, aramid rope 301, sheath 4, paraffin-based filler 5. Detailed Implementation

[0074] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with existing known technologies. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0075] This embodiment proposes a method for preparing a tensile-resistant, environmentally friendly, and energy-saving cable, including the following steps:

[0076] S1. Preparation of single-strand wire cores, this step specifically includes:

[0077] S101, Aluminum Core Processing

[0078] The electrical grade aluminum rod is drawn to the designed diameter (2.5mm for example), cut into fixed lengths of aluminum wire, and the surface is polished to remove the oxide layer, thus obtaining aluminum core 101A.

[0079] S102, copper cladding and nickel plating

[0080] A continuous extrusion coating process is used to form a copper cladding 101B on the outside of the aluminum core 101A, with the copper layer thickness controlled at 15-25% of the radius of the aluminum core (e.g., 0.19-0.31mm).

[0081] A nickel layer (thickness ≥ 1 μm) is electroplated on the outer surface of the copper-clad 101B to prevent high-temperature oxidation;

[0082] S103, coated with modified BN lubricating layer

[0083] Vinyl modified BN and vinyl polydimethylsiloxane are mixed at a weight ratio of 1.8-2.3:1 and stirred into a uniform slurry. The slurry is then applied to the surface of the copper cladding by dip coating or spraying to form a thin layer (5-10 μm thick). The slurry is pre-cured at 80°C for 5 min to obtain the modified BN lubricating layer.

[0084] S104, extrusion and vulcanization

[0085] The insulating material 101D is mixed and kneaded at 40-50℃ to form an extrusion material, which is then extruded onto the modified BN lubricating layer 101C. It is then pre-cured at 120-130℃ for 10 minutes to allow the hydrogen-containing silicone oil to penetrate into the BN layer for cross-linking. Finally, it is infrared-cured at 200±5℃ for 20 minutes to form a silicone / BN reinforced structure, thus obtaining the single-strand wire core 101.

[0086] The mixture is compounded at 40-50℃ to form an extrusion material, which is then extruded onto the modified BN lubricating layer 101C at 30-40℃. Subsequently, it is pre-vulcanized at 120-130℃ to allow the hydrogen-containing silicone oil to penetrate into the interior of the modified BN lubricating layer 101C and cross-link with the vinyl-modified BN and vinyl polydimethylsiloxane. Finally, it is infrared vulcanized at 200±5℃ to obtain the insulating skin 101D, which is a silicone / BN reinforced thin layer structure formed by the connection of vinyl-modified BN and silicone network. This prevents the powder from falling off during lubrication, which would cause uneven lubrication. Especially during dragging, stretching or bending, the difference in deformation between silicone and metal core makes the stability of the lubrication layer particularly important.

[0087] S2, Cable core stranding

[0088] The raw material of paraffin-based filler 5 is heated to 60℃ to become a paste, which is coated on the outside of the wire core 101 (thickness is 3-5μm). Then, multiple single-strand wire cores 101 are bundled together in a concentric twisting manner, with a twisting pitch ≤ 15 times the outer diameter of the cable core. After the twisted cable core bundle is rounded through a cylindrical through hole, it is cooled to obtain a paraffin-coated cable core.

[0089] S3, Shielding layer wrapping treatment

[0090] Outside the paraffin-coated cable core, conductive polyimide tape (50cm wide, with an overlap rate of 40-60%) is spirally wrapped to form a tape shielding layer 2;

[0091] S4, Extruded insulation layer

[0092] PVC rubber is extruded over the shielding layer to form an insulating layer. Aramid ropes 301 are pre-placed in the die of the extruder and are evenly distributed in a ring inside the insulating layer 3 (spaced 2-3mm). The extrusion temperature is 160-180℃, and the material is cooled and shaped.

[0093] S5, Sheath Molding

[0094] Cross-linked polyethylene (XLPE) is extruded over the insulation layer at a temperature of 120-140℃ (to avoid high temperature damage to the aramid rope), and then vulcanized at 180℃ for 30 minutes using infrared technology to obtain sheath 4.

[0095] S6, Post-processing

[0096] The sheath 4 obtained from S5 is cooled to room temperature in a water-cooling tank, and then wound up under tension control (to prevent deformation). The irregular section at the end is cut off to obtain the energy-saving cable product.

[0097] This embodiment also provides a product obtained by the aforementioned preparation process: a tensile-resistant, environmentally friendly, and energy-saving cable, which includes, from the inside out, a cable core 1, a winding shielding layer 2, an insulation layer 3, and a sheath 4. The cable core 1 is formed by twisting together multiple independent wire cores 101. The wire core 101 includes, from the inside out, an aluminum core 101A, a copper sheath 101B, a modified BN lubricating layer 101C, and an insulation sheath 101D. Paraffin-based filler 5 is filled between adjacent wire cores 101.

[0098] The aluminum core 101A is a lightweight conductor, reducing cost and energy consumption.

[0099] The outer layer of the copper-clad 101B is nickel-plated to avoid the negative reactions of high-temperature oxidation or other corrosion of copper during the extrusion process. The thickness of the copper-clad 101B is 15-25% of the radius of the aluminum core 101A.

[0100] The modified BN lubricating layer 101C is made by mixing vinyl modified BN and vinyl polydimethylsiloxane in a weight ratio of 1.8-2.3:1. Later, it is vulcanized with silicone to form a fixed thin-layer lubricating structure between the modified BN lubricating layer 101C and the insulating skin 101D.

[0101] The synthesis steps of vinyl-modified BN are as follows:

[0102] S01, BN hydroxylation pretreatment

[0103] 20 g of h-BN was dispersed in 200 ml of 65% (w / w) concentrated nitric acid aqueous solution, refluxed at 80 °C for 6 hours, centrifuged, washed with deionized water until neutral, and vacuum dried to obtain hydroxylated BN with a hydroxyl density of 12-15 hydroxyl groups / nm. 2 ;

[0104] SO2, silane hydrolysis activation

[0105] Under a dry nitrogen atmosphere, 5g of KH-570 was dissolved in 100ml of anhydrous toluene; 0.5ml of deionized water was added dropwise, and the mixture was stirred for 30min; then 0.1g of triethylamine was added, and the mixture was reacted at 40℃ for 2h to obtain a hydrolyzed silane solution.

[0106] The hydrolysis reaction formula is as follows:

[0107]

[0108] SO3, silane grafting reaction

[0109] Under nitrogen protection, 10g of hydroxylated BN was added to a hydrolyzed silane solution and ultrasonically dispersed for 30min; the temperature was raised to 110℃ and refluxed for 8h to obtain the reaction solution; samples were taken every 2h to detect the methanol content in toluene, and the reaction endpoint was defined as methanol release > 95% of the theoretical value.

[0110] S04, Post-processing and purification

[0111] The reaction solution was cooled to room temperature and the solid was collected by centrifugation. The solid was then washed three times with toluene and ethanol by ultrasonication to remove physically adsorbed silane. The solid was dried under vacuum at 60°C for 12 hours to obtain vinyl-modified BN.

[0112] Insulating film 101D is made of silicone and is prepared from the following raw materials:

[0113] 10 kg vinylsiloxane raw rubber, 0.4-0.5 kg polyvinylsiloxane raw rubber, 1.2-1.5 kg hydrogen-containing silicone oil, 0.1-0.15 kg platinum (0-1,3-diethylene-1,1,3,3-tetramethyldisiloxane casster catalyst to promote the crosslinking of the active hydrogen of the hydrogen-containing silicone oil with vinyl groups, and 1-5 g 1-ethynylcyclohexanol inhibitor to prevent premature local crosslinking into gel.

[0114] The winding shielding layer 2 is made of conductive PI tape spirally wrapped, which takes into account electromagnetic shielding, high temperature resistance and flexibility.

[0115] The insulation layer 3 is made of PVC rubber, which has a low cost. Aramid rope 301 is distributed in a ring inside the insulation layer 3 to further improve the tensile strength and the ability to resist large deformation of the cable core.

[0116] Sheath 4 is made of cross-linked polyethylene (XLPE), an environmentally friendly material with high weather resistance, aging resistance, and mechanical strength.

[0117] Paraffin-based filler 5 is a mixture of paraffin (which melts at 55-65℃ and absorbs heat), expanded graphite (pore size 100-300μm), and nano-alumina (particle size 15-60nm) in a weight ratio of 10:1-2:1-2.

[0118] Among them, the raw materials of insulating skin 101D include:

[0119] Vinyl siloxane raw rubber is a long-chain polysiloxane with vinyl short links at both ends of its macromolecular chain. It is in the form of solid raw rubber with a molecular weight of 300,000-400,000 and a vinyl content of 0.02-0.03 mmol vinyl / g vinyl siloxane raw rubber.

[0120] Polyvinylsiloxane raw rubber is a long-chain polysiloxane with vinyl short links at both ends or on the side chains of its macromolecular chain. It is in the form of solid raw rubber, with a molecular weight of 300,000-400,000 and a vinyl content of 2-3 mmol vinyl / g.

[0121] Hydrogen-containing silicone oil is a polydimethyl silicone oil with Si-H bonds and a hydrogen content of 4-6 mmol / g.

[0122] Next, regarding the preparation method of a tensile-resistant, environmentally friendly, and energy-saving cable, the following Examples 1-3 are provided, as detailed in Table 1 below:

[0123] Table 1. High-performance cable formulation

[0124]

[0125] Based on Example 1, the following comparative examples 1-7 were designed, as detailed in Table 2 below:

[0126] Table 2. High-performance cable formulations with single-factor variations

[0127]

[0128] It should be noted that Comparative Example 4 uses vinyl-free polymethylsiloxane raw rubber with a molecular weight of 1 million instead of the vinyl siloxane raw rubber and polyvinyl siloxane raw rubber in Example 1.

[0129] Performance testing

[0130] 1. Tensile strength test (≥150% of design load)

[0131] Referring to IEC 60228 and GB / T 5023.5-2008 conductor tensile test, the design load = 67% of the nominal breaking strength of the cable (safety factor 1.5) to verify the cable's resistance to deformation under extreme mechanical stress (such as drag laying, wind load) and ensure structural integrity.

[0132] Test methods

[0133] 1.1 Sample Preparation:

[0134] Cut a 1m long sample of cable and crimp copper terminals to both ends (to prevent slippage of the clamp).

[0135] Preload 50% of the design load (to eliminate initial gaps).

[0136] 1.2 Loading Process:

[0137] Apply the load at a rate of 10 mm / min to 150% of the design load (e.g., if the design load is 10 kN, apply the load to 15 kN).

[0138] Hold the load for 10 minutes and record the real-time deformation (laser displacement sensor accuracy ±0.01mm).

[0139] 1.3. Acceptance Criteria:

[0140] Permanent deformation rate ≤ 3% (length change after unloading / original length);

[0141] Unsheath cracks, exposed shielding layer, broken conductor.

[0142] 2. Conductivity test (50Hz AC resistance ≤ 110% of that of pure copper cable of the same specification)

[0143] Referring to the AC resistance measurement method of IEC 60287, the actual conductivity of copper-clad aluminum conductors under the skin effect was verified to confirm their energy-saving characteristics.

[0144] Comparison benchmark: pure copper cable with the same cross-sectional area (e.g., 35mm²) (resistivity 0.01724Ω·mm² / m).

[0145] Test methods

[0146] 2.1 Environmental Control:

[0147] The temperature was kept constant at 20±1℃ to eliminate the influence of the temperature coefficient (copper: 0.00393 / ℃).

[0148] 2.2 Four-end method measurement:

[0149] Using a precision LCR meter (Agilent 4294A), frequency 50Hz, current 1A (to avoid self-heating effect); measure the AC resistance R of a 1km cable. ac :

[0150]

[0151] 3. High-voltage insulation test (no breakdown at 3.5kV / 5min power frequency)

[0152] The dielectric strength of a multilayer insulation system (modified BN layer + silicone + XLPE sheath) under overvoltage was evaluated according to IEC 60502-2 power frequency withstand voltage test.

[0153] Test methods

[0154] 3.1 Sample preparation:

[0155] The samples were immersed in 25℃ saline (conductivity 20mS / m) for 24 hours to simulate a humid environment.

[0156] 3.2, Boosting Procedure:

[0157] The voltage is boosted to 3.5kV at a rate of 1kV / s;

[0158] Hold the pressure for 5 minutes and monitor the leakage current (threshold ≤10mA).

[0159] Tested at a pressure value equal to 3.5 times the rated voltage (0.6 / 1kV) (simulating harsh operating conditions);

[0160] 3.3 Failure Detection:

[0161] Breakdown (arc conduction; qualified products must not break down under 3.5kV / 5min power frequency);

[0162] The leakage current suddenly increased by more than 10mA.

[0163] The test data for the above three performance tests are shown in Table 3.

[0164] Table 3. Cable Performance Testing

[0165]

[0166] As shown in Table 3, compared to Comparative Example 1, the aluminum core in Example 1 provides mechanical support, reducing material usage by 30%. Furthermore, compared to Comparative Example 2, Example 1 ensures that >95% of the current is conducted through the copper layer (the resistance of the aluminum core in Example 1 is approximately 108% of that of the pure copper core in Comparative Example 1), significantly reducing high-frequency resistivity. Compared to Comparative Example 2, in the copper-clad aluminum structure of Example 1, the copper layer (tensile strength ≥200MPa) compensates for the weakness of the aluminum core (strength 80MPa), increasing the overall strength by 120%.

[0167] Compared with Example 1, Comparative Example 3 lacks a lubricating layer, and the copper-silicone interface may be easily peeled off due to deformation differences, causing partial discharge (the breakdown voltage of Comparative Example 3 decreased by 16%).

[0168] Compared with Comparative Example 4, in Example 1, Vi-BN and Vi-PDMS were embedded into the silica gel network via a hydrosilylation reaction (chemical bonding), and the BN sheets had a hydroxyl density of 12-15 hydroxyl groups / nm. 2 ) provides directional lubrication, which can reduce frictional loss (the deformation rate of Comparative Example 3 is increased by 133%), while Comparative Example 4 has the weakest interfacial bonding between vinyl silicone and BN, resulting in the highest deformation rate;

[0169] Compared with Comparative Example 5, the paraffin-based filler in Example 1 provides phase change paraffin to absorb deformation energy, and nano-Al2O3 enhances the filler stiffness, reducing the deformation rate by 67%. At the same time, phase change energy absorption can improve thermal conductivity and reduce high-frequency resistivity.

[0170] Under the skin depth constraint (δ=9.3mm), when the copper layer thickness of Example 1 is ≥0.2mm (>δ / 46), 98% of the current flows in the copper layer, while the thickness of Comparative Example 6 is insufficient, and the contribution of the aluminum core increases.

[0171] Among them, Comparative Example 7 cracked after thermal cycling, indicating that the paraffin was not encapsulated and was prone to local bulging when heated, resulting in a reduction in all aspects of its performance.

[0172] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A tensile-resistant, environmentally friendly, and energy-saving cable, characterized in that, From the inside out, the cable core (1), the winding shielding layer (2), the insulation layer (3) and the sheath (4) are arranged in sequence. The cable core (1) is made of multiple independent wire cores (101) twisted together. The wire core (101) includes an aluminum core (101A), a copper sheath (101B), a modified BN lubricating layer (101C) and an insulation sheath (101D) from the inside out. Paraffin-based filler (5) is filled between adjacent wire cores (101). The modified BN lubricating layer (101C) is composed of vinyl-modified BN and vinyl polydimethylsiloxane mixed in a weight ratio of 1.8-2.3:1; The synthesis steps of the vinyl-modified BN are as follows: S01. Disperse h-BN in concentrated nitric acid aqueous solution to perform BN hydroxylation pretreatment, obtaining hydroxylated BN with a hydroxyl group density of 12-15 hydroxyl groups / nm. 2 ; S02. KH-570 was activated by silane hydrolysis using anhydrous toluene, deionized water, and triethylamine to obtain a hydrolyzed silane solution. S03. A silane grafting reaction was carried out using hydroxylated BN and hydrolyzed silane solution to obtain a reaction solution; S04. The reaction solution is post-treated and purified to obtain vinyl-modified BN.

2. The tensile-resistant, environmentally friendly, and energy-saving cable according to claim 1, characterized in that, S01 specifically includes: dispersing 20gh-BN in 200ml of concentrated nitric acid aqueous solution with a weight concentration of 65%, refluxing at 80℃ for 6 hours, centrifuging, washing with deionized water until neutral, and vacuum drying to obtain hydroxylated BN; Specifically, SO2 includes: under nitrogen protection, dissolving 5g KH-570 in 100ml anhydrous toluene; adding 0.5ml deionized water dropwise and stirring for 30min; adding 0.1g triethylamine and reacting at 40℃ for 2h to obtain a hydrolyzed silane solution; Specifically, SO3 includes: under nitrogen protection, 10g of hydroxylated BN is added to a hydrolyzed silane solution, ultrasonically dispersed for 30min, heated to 110℃, and refluxed for 8h to obtain a reaction solution; S04 specifically includes: cooling the reaction solution to room temperature, centrifuging to collect the solid; ultrasonically washing with toluene and ethanol three times in sequence to remove physically adsorbed silane; and vacuum drying at 60℃ for 12h to obtain vinyl-modified BN.

3. The tensile-resistant, environmentally friendly, and energy-saving cable according to claim 1, characterized in that, The winding shielding layer (2) is made of conductive polyimide tape spirally wrapped.

4. The tensile-resistant, environmentally friendly, and energy-saving cable according to claim 1, characterized in that, The insulating layer (3) is made of PVC rubber, and aramid ropes (301) are distributed in a ring inside the insulating layer (3).

5. The tensile-resistant, environmentally friendly, and energy-saving cable according to claim 1, characterized in that, The sheath (4) is made of cross-linked polyethylene.

6. The tensile-resistant, environmentally friendly, and energy-saving cable according to claim 1, characterized in that, The paraffin-based filler (5) is a mixture of paraffin, expanded graphite and nano-alumina in a weight ratio of 10:(1-2):(1-2).

7. The tensile-resistant, environmentally friendly, and energy-saving cable according to claim 1, characterized in that, The insulating skin (101D) is made of silicone material and is prepared from the following raw materials: vinyl siloxane raw rubber, polyvinyl siloxane raw rubber, hydrogen-containing silicone oil, platinum (0)-1,3-diethylene-1,1,3,3-tetramethyldisiloxane, and 1-ethynylcyclohexanol. The vinyl siloxane raw rubber is a long-chain polysiloxane with vinyl short links at both ends of the macromolecular chain. It is in the form of solid raw rubber with a molecular weight of 300,000-400,000 and a vinyl content of 0.02-0.03 mmol / g. The polyvinylsiloxane raw rubber is a long-chain polysiloxane with vinyl short links at both ends or on the side chains of the macromolecular chain. It is in the form of solid raw rubber, with a molecular weight of 300,000-400,000 and a vinyl content of 2-3 mmol / g. The hydrogen-containing silicone oil is a polydimethyl silicone oil with Si-H bonds and a hydrogen content of 4-6 mmol / g.

8. A method for preparing a tensile-resistant, environmentally friendly, and energy-saving cable as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Prepare single-strand wire cores; S2. The raw material of paraffin-based filler is heated to 60℃ to become a paste, which is coated on the outside of the wire core. Then, multiple single-strand wire cores are bundled together in a concentric twisting manner. The twisting pitch is ≤ 15 times the outer diameter of the cable core. After the twisted cable core bundle is rounded through a cylindrical through hole, it is cooled to obtain the paraffin-coated cable core. S3. Outside the paraffin-coated cable core, a conductive polyimide tape is spirally wrapped to form a tape shielding layer; S4. PVC rubber is extruded over the shielding layer to form an insulating layer. Aramid ropes are pre-placed in the die of the extruder and are evenly distributed in a ring inside the insulating layer. The extrusion temperature is 160-180℃, and the material is cooled and shaped. S5. Extrude cross-linked polyethylene over the insulation layer at an extrusion temperature of 120-140℃, and then vulcanize at 180℃ for 30 minutes to obtain the sheath. S6. Cool the sheath to room temperature in a water-cooling tank, then roll it up under tension control, and cut off the irregular ends to obtain an energy-saving cable.

9. The method for preparing a tensile-resistant, environmentally friendly, and energy-saving cable as described in claim 8, characterized in that, S1 specifically includes: S101. Draw the electrical grade aluminum rod to the designed diameter, cut it into fixed length aluminum wires, polish the surface, remove the oxide layer, and obtain the aluminum core; S102. A continuous extrusion coating process is used to form a copper cladding on the outside of the aluminum core, with the copper layer thickness controlled at 15-25% of the aluminum core radius; a nickel layer is electroplated on the outer surface of the copper cladding. S103. Mix vinyl-modified BN with vinyl polydimethylsiloxane at a weight ratio of 1.8-2.3:1, stir to form a uniform slurry, and form a thin layer on the surface of copper cladding by dip coating or spraying. Pre-cur at 80°C for 5 minutes to obtain the modified BN lubricating layer. S104. The insulating material is mixed and kneaded at 40-50℃ to form an extrusion material, which is then extruded onto the modified BN lubricating layer. It is pre-cured at 120-130℃ for 10 minutes to allow the hydrogen-containing silicone oil to penetrate into the BN layer for cross-linking. Then, it is infrared-cured at 200±5℃ for 20 minutes to form a silicone / BN reinforced structure, thus obtaining a single-strand wire core.

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