10kv overhead insulated conductor and method of making same

Abstract

The application relates to the technical field of cables, and discloses a 10kV overhead insulated conductor. The preparation steps of the 10kV overhead insulated conductor include the following steps: dissolving aluminum isopropyl alcohol in ethanol, adding water and continuously stirring; then, adding nano zinc oxide into the sol, and obtaining AlOOH@ZnO after heat treatment; ultrasonic dispersing AlOOH@ZnO in ethanol, then adding a silane hydrolysis solution into the AlOOH@ZnO, and reacting for 2-3 hours under the condition of 70-80 DEG C to obtain silanized AlOOH@ZnO; once mixing high-density polyethylene, ethylene-octene copolymer and an antioxidant, and then twice mixing the silanized AlOOH@ZnO, organic montmorillonite, zinc stearate and polyethylene wax to obtain an insulating layer mixing material; extruding the insulating layer mixing material to coat the conductor, and obtaining the 10kV overhead insulated conductor after cooling and shaping. The 10kV overhead insulated conductor improves the insulation, weather resistance and mechanical properties of the conductor.

Description

Technical Field

[0001] This invention relates to the field of cable technology, specifically to a 10kV overhead insulated conductor and its preparation method. Background Technology

[0002] In power transmission systems, 10kV overhead lines are a crucial component of the distribution network, undertaking the critical task of distributing electrical energy from substations to various users. Traditional bare conductor overhead lines present numerous safety hazards during operation, such as the risk of electric shock and short circuits due to external environmental influences. To ensure the safety and reliability of power transmission, 10kV overhead insulated conductors have been developed. By wrapping the conductor with insulating material, these problems are effectively avoided, improving the operational stability and safety of the line.

[0003] 10kV overhead insulated conductors play a crucial role in power transmission. However, existing 10kV overhead insulated conductors and their manufacturing methods suffer from insufficient insulation performance, poor mechanical properties, poor weather resistance, and complex manufacturing processes. These problems not only affect the service life and safety of the conductors but also increase the operating costs of power companies. Therefore, it is necessary to develop a novel 10kV overhead insulated conductor and its manufacturing method to address the shortcomings of existing technologies, improve conductor performance and quality, and meet the ever-evolving needs of the power industry. To solve the aforementioned technical problems, this invention proposes a new 10kV overhead insulated conductor. Summary of the Invention

[0004] This invention proposes a 10kV overhead insulated conductor that improves the conductor's insulation, weather resistance, and mechanical properties.

[0005] The technical solution of the present invention is as follows: In a first aspect, the present invention proposes a method for preparing a 10kV overhead insulated conductor, the steps of which include: (1) Dissolve aluminum isopropoxide in ethanol and stir to obtain a transparent sol. Add water and continue stirring. Then add nano zinc oxide into the sol for impregnation and coating. After heat treatment, AlOOH@ZnO is obtained. (2) Add silane coupling agent KH550 to a mixture of ethanol and water to obtain silane hydrolysate; disperse AlOOH@ZnO in ethanol by ultrasonication, then add silane hydrolysate to it, react at 70-80℃ for 2-3h, centrifuge, wash and dry to obtain silanized AlOOH@ZnO; (3) High-density polyethylene, ethylene-octene copolymer and antioxidant are mixed in one step, and silanized AlOOH@ZnO, organomontmorillonite, zinc stearate and polyethylene wax are added and mixed in a second step to obtain insulation layer compound; (4) The compound is extruded and coated on the outside of the conductor using a twin-screw extruder, while the diisopropylbenzene peroxide is injected online. After cooling and shaping, the 10kV overhead insulated conductor is obtained.

[0006] As a further technical solution, the insulating layer compound comprises the following raw materials in parts by weight: 100 parts high-density polyethylene, 20-25 parts AlOOH@ZnO, 8-10 parts organomontmorillonite, 10-12 parts ethylene-octene copolymer, 0.5-0.7 parts antioxidant, 1.5-2 parts dicumyl peroxide, 0.2-0.4 parts zinc stearate, and 0.4-0.6 parts polyethylene wax.

[0007] As a further technical solution, the weight ratio of aluminum isopropoxide, ethanol, water and nano zinc oxide in step (1) is 1:(10-15):(0.05-0.15):(0.3-0.5).

[0008] As a further technical solution, the stirring time for obtaining the transparent sol in step (1) is 30-40 min, and the stirring time after adding water is 60-70 min.

[0009] As a further technical solution, the heat treatment step in step (1) includes pre-drying at 75-85℃ for 30-40 min, followed by annealing at 280-320℃ for 60-70 min.

[0010] As a further technical solution, the hydrolysate preparation method in step (2) is as follows: add silane coupling agent KH550 to a mixture of ethanol and water and stir, add glacial acetic acid to adjust the pH to 4.5±0.1, and hydrolyze at 35-45℃ for 30-40 min; wherein, the weight ratio of silane coupling agent KH550, ethanol and water is 0.01-0.03:10-20:0.1-0.3.

[0011] As a further technical solution, the weight ratio of AlOOH@ZnO and silane coupling agent KH550 in step (2) is 1:0.1-0.3.

[0012] As a further technical solution, in step (3), the first mixing is carried out at 175-185℃ for 5-8 minutes; the second mixing is carried out at 185-195℃ and 60-70 rpm for 8-10 minutes.

[0013] As a further technical solution, in step (4), the twin-screw extruder has an L / D ≤ ​​36 and a die temperature of 190-200℃.

[0014] Secondly, this invention proposes a 10kV overhead insulated conductor, which is prepared using the aforementioned preparation method.

[0015] The working principle and beneficial effects of this invention are as follows: This invention constructs a silanized AlOOH@ZnO composite filler through multi-step synergistic modification, achieving dual optimization of filler dispersibility and interfacial bonding. First, aluminum isopropoxide is hydrolyzed to coat nano-zinc oxide, forming an AlOOH@ZnO core-shell structure. The layered structure of AlOOH inhibits ZnO aggregation, while heat treatment forms a stable crystalline structure, providing uniform reaction sites for subsequent silanization. Second, the silane coupling agent KH550 is hydrolyzed under acidic conditions to generate silanol groups, which condense with the hydroxyl groups on the AlOOH surface to form a chemically bonded silanized layer. This process not only enhances the compatibility of the filler with the polyethylene matrix but also reduces interfacial stress concentration through the flexible transition of the organic long chain, effectively inhibiting interfacial debonding under mechanical loads or damp heat aging conditions. Experiments show that silanization treatment does not significantly change electrical properties and flame retardancy, but it significantly improves the tensile strength and damp heat aging resistance retention of the material through interfacial strengthening.

[0016] This invention constructs a dual-filler system by introducing organo-montmorillonite and silanized AlOOH@ZnO, utilizing their morphological differences to create a complementary reinforcement mechanism. The organo-montmorillonite, dispersed in the matrix in a layered structure, inhibits crack propagation through physical barrier effects. Simultaneously, the surface-modified organic groups interact with the silanized filler through van der Waals forces, promoting the continuity of the filler network. The silanized AlOOH@ZnO, in nanoparticle form, fills the gaps between the montmorillonite layers. This synergistic effect not only improves the mechanical strength of the material but also reduces the moisture penetration pathway through the densification of the filler network, significantly enhancing volume resistivity and resistance to damp heat aging.

[0017] This invention introduces an ethylene-octene copolymer into a high-density polyethylene (HDPE) matrix, using its unique branched structure to regulate the matrix's toughness. When the material is subjected to external forces, the ethylene-octene copolymer absorbs energy through plastic deformation, inhibiting crack initiation and propagation, thereby compensating for the increased brittleness caused by inorganic fillers. Simultaneously, the ethylene-octene copolymer exhibits superior resistance to humid heat aging compared to HDPE; the tertiary carbon atoms in its molecular chain reduce hydrolytic reactivity through steric hindrance, delaying performance degradation caused by matrix degradation under humid heat conditions. Furthermore, the interfacial interaction between the ethylene-octene copolymer and the silanized filler further optimizes stress transfer efficiency. Detailed Implementation

[0018] The technical solutions 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.

[0019] It should be noted that the high-density polyethylene used in this invention was purchased from PetroChina Jilin Petrochemical Company, with the grade DFDA-7042; the organomontmorillonite was purchased from Zhejiang Fenghong New Material Co., Ltd., with the grade DK1N; the ethylene-octene copolymer was purchased from Mitsui Chemicals, with a melt index of 3.6 g / 10 min; and the polyethylene wax was purchased from Guangzhou Binlong Chemical Co., Ltd., with the model D1100.

[0020] Example 1 This embodiment provides a 10kV overhead insulated conductor and a method for preparing the 10kV overhead insulated conductor, the steps of which include: (1) Dissolve 10g aluminum isopropoxide in 125g ethanol and stir at 150rpm for 35min to obtain a transparent sol. Add 1g water and continue stirring for 65min. Then add 4g nano zinc oxide into the sol for impregnation and coating. Pre-dry at 80℃ for 35min and then anneal at 300℃ for 65min to obtain AlOOH@ZnO. (2) Add 0.02g of silane coupling agent KH550 to a mixture of 15g of ethanol and 0.2g of water and stir. Add glacial acetic acid to adjust the pH to 4.5. Hydrolyze at 40℃ for 35min to obtain silane hydrolysate. Disperse 1g of AlOOH@ZnO in 100mL of ethanol by ultrasonication. Then add silane hydrolysate to it. React at 75℃ for 2.5h. Centrifuge at 8000rpm for 5min. Wash with ethanol 3 times. Dry under vacuum at 60℃ for 12h to obtain silanized AlOOH@ZnO. (3) 100g of high-density polyethylene, 11g of ethylene-octene copolymer and 0.6g of antioxidant 1010 were mixed at 180℃ for 6min. 22g of silanized AlOOH@ZnO, 9g of organomontmorillonite, 0.3g of zinc stearate and 0.5g of polyethylene wax were added and mixed at 190℃ and 65rpm for 9min to obtain the insulating layer compound. (4) The compound was extruded and coated on the outside of the conductor using a twin-screw extruder. The twin-screw extruder had an L / D of 36 and a die temperature of 195°C. At the same time, 1.8 parts of dicumyl peroxide were injected online. After cooling and shaping, a 10kV overhead insulated conductor was obtained.

[0021] Example 2 This embodiment provides a 10kV overhead insulated conductor and a method for preparing the 10kV overhead insulated conductor, the steps of which include: (1) Dissolve 10g aluminum isopropoxide in 100g ethanol and stir at 150rpm for 30min to obtain a transparent sol. Add 0.5g water and continue stirring for 60min. Then add 3g nano zinc oxide into the sol for impregnation and coating. Pre-dry at 75℃ for 30min and then anneal at 280℃ for 60min to obtain AlOOH@ZnO. (2) Add 0.01g of silane coupling agent KH550 to a mixture of 10g ethanol and 0.1g water and stir. Add glacial acetic acid to adjust the pH to 4.5. Hydrolyze at 35℃ for 30min to obtain silane hydrolysate. Disperse 1g AlOOH@ZnO in 100mL ethanol by ultrasonication. Then add silane hydrolysate to it. React at 70℃ for 2h. Centrifuge at 8000rpm for 5min. Wash with ethanol 3 times. Dry under vacuum at 60℃ for 12h to obtain silanized AlOOH@ZnO. (3) 100g of high-density polyethylene, 10g of ethylene-octene copolymer and 0.5g of antioxidant 1010 were mixed at 175℃ for 5min, and 20g of silanized AlOOH@ZnO, 8g of organomontmorillonite, 0.2g of zinc stearate and 0.4g of polyethylene wax were added and mixed at 185℃ and 60rpm for 8min to obtain the insulating layer compound; (4) The compound was extruded and coated on the outside of the conductor using a twin-screw extruder. The twin-screw extruder had an L / D of 36 and a die temperature of 190°C. At the same time, 1.5g of dicumyl peroxide was injected online. After cooling and shaping, a 10kV overhead insulated conductor was obtained.

[0022] Example 3 This embodiment provides a 10kV overhead insulated conductor and a method for preparing the 10kV overhead insulated conductor, the steps of which include: (1) Dissolve 10g aluminum isopropoxide in 150g ethanol and stir at 150rpm for 40min to obtain a transparent sol. Add 1.5g water and continue stirring for 70min. Then add 5g nano zinc oxide into the sol for impregnation and coating. Pre-dry at 85℃ for 40min and then anneal at 320℃ for 70min to obtain AlOOH@ZnO. (2) Add 0.03g of silane coupling agent KH550 to a mixture of 20g ethanol and 0.3g water and stir. Add glacial acetic acid to adjust the pH to 4.5. Hydrolyze at 45℃ for 40min to obtain silane hydrolysate. Disperse 1g AlOOH@ZnO in 100mL ethanol by ultrasonication. Then add silane hydrolysate to it. React at 80℃ for 3h. Centrifuge at 8000rpm for 5min. Wash with ethanol 3 times. Dry under vacuum at 60℃ for 12h to obtain silanized AlOOH@ZnO. (3) 100g of high-density polyethylene, 12g of ethylene-octene copolymer and 0.7g of antioxidant 1010 were mixed at 185℃ for 8min. 25g of silanized AlOOH@ZnO, 10g of organomontmorillonite, 0.4g of zinc stearate and 0.6g of polyethylene wax were added and mixed at 195℃ and 70rpm for 10min to obtain the insulating layer compound. (4) The compound is extruded and coated on the outside of the conductor using a twin-screw extruder. The twin-screw extruder has an L / D ratio of 36 and a die temperature of 200℃. At the same time, 2g of dicumyl peroxide is injected online. After cooling and shaping, a 10kV overhead insulated conductor is obtained.

[0023] Comparative Example 1 This is an adjustment based on Example 1, but unlike Example 1, AlOOH@ZnO and organomontmorillonite are not added at all.

[0024] Comparative Example 2 The method is based on Example 1, but with adjustments. Unlike Example 1, ordinary ZnO is used instead of AlOOH@ZnO, and the aluminum isopropoxide coating step is omitted.

[0025] Comparative Example 3 Based on Example 1, an adjustment was made, but unlike Example 1, step (2) was skipped, and unsilanized AlOOH@ZnO was used directly.

[0026] Comparative Example 4 The method was adjusted based on Example 1, except that the amount of silanized AlOOH@ZnO was reduced to 5g.

[0027] Comparative Example 5 The method was adjusted based on Example 1, except that the amount of silanized AlOOH@ZnO was increased to 40g.

[0028] Comparative Example 6 The method is based on Example 1, but with the ethylene-octene copolymer omitted.

[0029] Comparative Example 7 This is an adjustment based on Example 1, except that the organomontmorillonite is omitted.

[0030] Comparative Example 8 The method is based on Example 1, but with the difference that silanized AlOOH@ZnO is omitted.

[0031] Test Example 1: The 10kV overhead insulated conductors prepared in Examples 1-3 and Comparative Examples 1-8 were subjected to the following tests: Tensile strength: Tested in accordance with GB / T1040.2-2006 standard; Volume resistivity: The resistivity at 20℃ was measured according to GB / 15662 standard; Limiting Oxygen Index (LOI): Tested according to GB / T 2406.2-2009 standard; Resistance to damp heat aging: The outer layer sample (100mm×100mm×2mm) covering the conductor was suspended in the aging chamber and kept at 85℃ and 85% RH for 168h. The tensile strength was tested and the tensile strength retention rate was calculated. The test results are shown in Table 1 below: Table 1

[0032] Based on the aforementioned data, Examples 1-3 demonstrate optimized performance of 10kV overhead insulated conductors. The combination of silanized AlOOH@ZnO and organomontmorillonite, along with ethylene-octene copolymer, significantly improves tensile strength, volume resistivity, limiting oxygen index, and resistance to damp heat aging. Example 1 exhibits the best performance, with a tensile strength of 22.1 MPa and a volume resistivity of 1.8 × 10⁻⁶. 15 The Ω·cm, LOI of 33.2%, and retention rate of 92% indicate that the filler is well dispersed and has strong interfacial bonding. The performance changes of Comparative Examples 1-8 confirm the role of key components: the coating of AlOOH@ZnO and the silanization treatment are the core to improve insulation and aging resistance; the ethylene-octene copolymer improves toughness; the filler dosage must be moderate, as both excess and deficiency will lead to performance degradation.

[0033] Comparative Example 1, which completely omitted AlOOH@ZnO and organomontmorillonite, showed a significant decrease in all properties, indicating that AlOOH@ZnO and organomontmorillonite are key to improving mechanical strength, insulation, flame retardancy, and aging resistance. Without them, the matrix resin cannot effectively resist aging and stress. Comparative Example 2, which replaced AlOOH@ZnO with ordinary ZnO and omitted the aluminum isopropoxide coating, showed slightly lower performance than Example 1, indicating that the AlOOH coating layer can improve ZnO dispersion and interfacial bonding, enhancing insulation and aging resistance; ordinary ZnO is prone to agglomeration, leading to a decrease in electrical and mechanical properties. Comparative Example 3, which directly used unsilanized AlOOH@ZnO, skipping step (2), showed a significant decrease in tensile strength and retention rate, while the volume resistivity and LOI were similar to those of the examples, indicating that silanization treatment does not directly affect electrical properties and flame retardancy, but can enhance the filler-matrix interfacial bonding and prevent interfacial degradation caused by humid heat aging. Comparative Example 4: Reducing the amount of silanized AlOOH@ZnO to 5g resulted in a comprehensive decline in performance, indicating that insufficient filler content cannot effectively reinforce the matrix, leading to insufficient insulation, flame retardancy, and mechanical strength; an appropriate amount of filler is crucial for overall performance. Comparative Example 5: Increasing the amount of silanized AlOOH@ZnO to 40g resulted in a decrease in tensile strength and volume resistivity, with a slight increase in LOI but acceptable retention, indicating that excessive filler leads to agglomeration, reducing mechanical strength and insulation; although flame retardancy is improved, it is prone to embrittlement in practical applications and is not suitable for high-voltage insulated conductors. Comparative Example 6: Omitting the ethylene-octene copolymer resulted in a slight increase in tensile strength but a significant decrease in retention, with little change in volume resistivity and LOI, indicating that the absence of the ethylene-octene copolymer makes the material brittle, with high initial strength but poor resistance to damp heat aging; the ethylene-octene copolymer is indispensable for improving toughness and durability. Comparative Example 7: Omitting organomontmorillonite resulted in a moderate decline in performance, indicating that organomontmorillonite contributes to mechanical reinforcement and flame retardancy; its absence results in an incomplete filler system and weakened aging resistance of the insulation layer. Comparative Example 8, omitting silanized AlOOH@ZnO, showed a more comprehensive deterioration in performance, indicating that silanized AlOOH@ZnO is the core functional filler, providing insulation, flame retardancy, and reinforcement. Its absence resulted in a similar performance to Comparative Example 1, but the remaining montmorillonite mitigated the decline. The performance degradation in Comparative Examples 1 and 7 further validated the necessity of the dual-filler system, demonstrating that a single filler cannot simultaneously achieve a balance between mechanical reinforcement and insulation / weather resistance. Comparative Example 6 showed a significant decrease in tensile strength retention, confirming the crucial role of the ethylene-octene copolymer in long-term durability.

[0034] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a 10kV overhead insulated conductor, characterized in that the steps include... include: (1) Dissolve aluminum isopropoxide in ethanol, stir to obtain a transparent sol, add water and continue stirring; Subsequently, nano-zinc oxide was added to the sol for impregnation and coating, and after heat treatment, AlOOH@ZnO was obtained; the weight ratio of aluminum isopropoxide, ethanol, water and nano-zinc oxide in step (1) was 1:(10-15):(0.05-0.15):(0.3-0.5); the stirring time for obtaining the transparent sol in step (1) was 30-40 min, and the stirring time after adding water was 60-70 min; (2) Add silane coupling agent KH550 to a mixture of ethanol and water to obtain silane hydrolysate; disperse AlOOH@ZnO in ethanol by ultrasonication, then add silane hydrolysate to it, react at 70-80℃ for 2-3h, centrifuge, wash and dry to obtain silanized AlOOH@ZnO; (3) High-density polyethylene, ethylene-octene copolymer and antioxidant are mixed in one step, and silanized AlOOH@ZnO, organomontmorillonite, zinc stearate and polyethylene wax are added and mixed in a second step to obtain insulation layer compound; (4) The compound is extruded and coated on the outside of the conductor using a twin-screw extruder, while the diisopropylbenzene peroxide is injected online. After cooling and shaping, the 10kV overhead insulated conductor is obtained. The insulating layer compound comprises the following raw materials in parts by weight: 100 parts high-density polyethylene, 0-25 parts silanized AlOOH@ZnO2, 8-10 parts organomontmorillonite, 10-12 parts ethylene-octene copolymer, 0.5-0.7 parts antioxidant, 1.5-2 parts dicumyl peroxide, 0.2-0.4 parts zinc stearate, and 0.4-0.6 parts polyethylene wax.

2. The method for preparing a 10kV overhead insulated conductor according to claim 1, characterized in that, The heat treatment steps in step (1) include: pre-drying at 75-85℃ for 30-40 min, followed by annealing at 280-320℃ for 60-70 min.

3. The method for preparing a 10kV overhead insulated conductor according to claim 1, characterized in that, The preparation method of the silane hydrolysate in step (2) is as follows: add silane coupling agent KH550 to a mixture of ethanol and water and stir, add glacial acetic acid to adjust the pH to 4.5±0.1, and hydrolyze at 35-45℃ for 30-40 min; wherein, the weight ratio of silane coupling agent KH550, ethanol and water is 0.01-0.03:10-20:0.1-0.

3.

4. The method for preparing a 10kV overhead insulated conductor according to claim 1, characterized in that, The weight ratio of AlOOH@ZnO and the silane coupling agent KH550 in step (2) is 1:0.01-0.

03.

5. The method for preparing a 10kV overhead insulated conductor according to claim 1, characterized in that, The first mixing in step (3) is mixing at 175-185℃ for 5-8 minutes; the second mixing is mixing at 185-195℃ and 60-70 rpm for 8-10 minutes.

6. The method for preparing a 10kV overhead insulated conductor according to claim 1, characterized in that, The twin-screw extruder described in step (4) has an L / D ≤ ​​36 and a die temperature of 190-200℃.

7. A 10kV overhead insulated conductor, characterized in that, It is prepared by the method for preparing a 10kV overhead insulated conductor according to any one of claims 1-6.

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