Overhead parallel bunched lead

Abstract

The invention relates to the technical field of wires and cables, and particularly discloses an overhead parallel bunched wire. An overhead parallel cluster lead comprises at least two leads which are arranged side by side, and the adjacent leads are fixedly connected with each other through a connecting rib. An insulating layer is arranged on the outer wall of the wire; the insulating layer is prepared from the following raw materials: crosslinked polyethylene, an antioxidant, an ultraviolet light absorber, nano magnesium oxide, methyl vinyl silicone rubber, flaky boron nitride and a silane coupling agent. The heat conductivity coefficient of the overhead parallel bunched wire is up to 0.60 W / mk, the lowest reduction rate of the elongation at break after thermal aging is 5.0%, the heat dissipation performance of the overhead parallel bunched wire is improved, the volume resistivity at 20 DEG C and the dielectric strength are 2.56 * 10 < 14 > omega.cm and 40kV / mm at most, and the insulation performance of the overhead parallel bunched wire is improved.

Description

Technical Field

[0001] The present application relates to the technical field of wires and cables, and more specifically, to an overhead parallel bundled conductor. Background Art

[0002] Overhead parallel bundled conductors, also known as parallel bundled insulated overhead cables, are a new type of low-voltage overhead insulated cable. They typically consist of two, three, or four insulated conductors connected in parallel to form a conductor bundle. Due to their advantages such as low line reactance, minimal space usage, simple line structure, reduced risk of electric shock, ease of installation, and low overall cost, parallel bundled overhead insulated cables are widely used in low-voltage lines in rural areas, towns and villages, old urban areas, urban villages, residential communities, and in neighborhoods with low commercial loads. With the launch of a new round of rural-urban power grid transformation, State Grid has significantly increased the number of parallel bundled overhead insulated cables in its product bidding.

[0003] However, existing overhead parallel bundled conductors have shortcomings in insulation and heat dissipation. On the one hand, traditional insulation materials are susceptible to aging in harsh environments over time, leading to a decline in insulation performance and increasing safety hazards such as leakage and short circuits. On the other hand, the conductors generate heat during power transmission. If this heat cannot be dissipated promptly, the conductor temperature will rise, accelerating insulation aging, reducing the conductor's service life, and even causing serious accidents such as fires. The shape and characteristics of the bundled conductor structure make its heat dissipation performance worse than that of a single conductor.

[0004] To improve the heat dissipation of overhead parallel bundled conductors, related technologies use heat-dissipating paint applied to the insulation surface to reduce surface temperature through radiative heat dissipation. However, the paint has limited adhesion and is prone to falling off due to long-term exposure to wind and rain, requiring regular maintenance. Furthermore, some paints may chemically react with the insulation material, degrading insulation performance. To improve the insulation of overhead parallel bundled conductors, thicker insulation layers are applied to the conductors. While this directly increases the insulation withstand voltage rating, the thicker insulation layer hinders heat dissipation, causing the conductor's operating temperature to rise and accelerating insulation aging. Summary of the Invention

[0005] In order to improve the insulation and heat dissipation of overhead parallel bundled conductors, the present application provides an overhead parallel bundled conductor.

[0006] In a first aspect, the present application provides an overhead parallel bundled conductor, which adopts the following technical solution: An overhead parallel bundled conductor comprises at least two conductors arranged side by side, with adjacent conductors fixedly connected to each other via connecting ribs; an insulating layer is provided on the outer wall of the conductor; The insulating layer comprises the following raw materials in parts by weight: 80-100 parts of cross-linked polyethylene, 0.5-1 part of antioxidant, 0.5-1 part of ultraviolet absorber, 3-5 parts of nano magnesium oxide, 5-15 parts of methyl vinyl silicone rubber, 4-10 parts of flaky boron nitride and 1-2 parts of silane coupling agent.

[0007] The insulating layer of the overhead parallel bundled conductor of the present application includes the following raw materials in parts by weight: 80-100 parts of cross-linked polyethylene, 0.5-1 part of antioxidant, 0.5-1 part of ultraviolet absorber, 3-5 parts of nano-magnesium oxide, 5-15 parts of methyl vinyl silicone rubber, 4-10 parts of flaky boron nitride, and 1-2 parts of silane coupling agent. Any value within the respective ranges can be selected, and the insulation and heat dissipation properties of the overhead insulated conductor can be improved.

[0008] By adopting the above technical solution, the insulation layer uses cross-linked polyethylene as the primary raw material, providing the insulation layer with basic mechanical strength and insulation properties. Antioxidants prevent oxidation reactions during processing and high-temperature environments of the overhead insulated cable, improving the sheath's weather resistance. UV absorbers absorb UV energy, preventing it from causing polymer molecular chain breakage, preventing sheath cracking, and improving the sheath's weather resistance. Nano-magnesium oxide is dispersed in methyl vinyl silicone rubber, filling the molecular gaps and forming a "rigid insulation skeleton" to enhance the insulation performance of the overhead parallel bundled conductors. Flake boron nitride has high thermal conductivity, optimizing heat dissipation paths and improving the heat dissipation of the overhead parallel bundled conductors. The flake boron nitride forms a parallel orientation in the cross-linked polyethylene, hindering the linear penetration path of electrons. Flake boron nitride has a low dielectric constant, and the layers are connected by weak van der Waals forces, making it difficult for electrons to cross the interlayer barrier, further enhancing insulation properties. By adding a silane coupling agent, one end of the molecule condenses with the hydroxyl groups on the surface of nano-magnesium oxide and flake boron nitride, and the other end initiates copolymerization with the vinyl group of silicone rubber through peroxide, thereby further improving the insulation performance of the overhead parallel bundled conductors.

[0009] Nano-magnesium oxide also fills the gaps between boron nitride flakes, reducing interfacial defects and making the insulation layer structure denser, further enhancing insulation effectiveness. Furthermore, boron nitride flakes provide long-range heat conduction paths, while nano-zinc oxide fills short-range gaps. Together, these two enhance the thermal conductivity of the overhead parallel bundled conductors, further improving their heat dissipation.

[0010] Preferably, the insulating layer comprises the following raw materials in parts by weight: 85-95 parts of cross-linked polyethylene, 0.7-0.9 parts of antioxidant, 0.7-0.9 parts of ultraviolet absorber, 3.5-4.5 parts of nano magnesium oxide, 8-12 parts of methyl vinyl silicone rubber, 5-7 parts of flaky boron nitride, and 1.3-1.8 parts of silane coupling agent.

[0011] The insulating layer of the present application uses 85-95 parts of cross-linked polyethylene, 0.7-0.9 parts of antioxidant, 0.7-0.9 parts of ultraviolet absorber, 3.5-4.5 parts of nano magnesium oxide, 8-12 parts of methyl vinyl silicone rubber, 5-7 parts of flaky boron nitride, and 1.3-1.8 parts of silane coupling agent. Any value within the respective ranges can be selected, and the insulation and heat dissipation properties of the overhead insulated conductor can be improved.

[0012] Preferably, the weight ratio of the nano-magnesium oxide to the methyl vinyl silicone rubber is 1:(2-4).

[0013] By adopting the above technical solution, the weight ratio of nano-magnesium oxide and methyl vinyl silicone rubber is adjusted, which is more conducive to the uniform dispersion of nano-magnesium oxide in methyl vinyl silicone rubber, thereby improving the insulating effect of nano-magnesium oxide and methyl vinyl silicone rubber in the insulating layer, thereby further improving the insulation performance of overhead parallel bundled conductors.

[0014] Preferably, the weight ratio of the nano-magnesium oxide to the flaky boron nitride is 1:(1.3-1.7).

[0015] By adopting the above technical solution and adjusting the weight ratio of nano-magnesium oxide to flaky boron nitride, the nano-magnesium oxide can be evenly filled in the gaps between the flaky boron nitride layers, which can further improve the heat dissipation and insulation properties of the overhead parallel bundled conductors.

[0016] As a preference: the nano magnesium oxide is prepared by modification, specifically: S1. Add stearic acid to the ethanol solution, stir and heat to 60-80°C to prepare a stearic acid solution with a concentration of 10-20%; S2. Dry the nano-magnesium oxide at 100-120°C for 2-4 hours, add it to the stearic acid solution, stir at 600-800 rpm, ultrasonically disperse for 15-30 minutes, and use an ultrasonic power of 300-500 W. Heat to 80-100°C, stir and react at a constant temperature for 2-4 hours, cool, filter, wash, and vacuum dry to obtain the modified nano-oxidase.

[0017] By adopting the above technical solution, stearic acid is used to modify the surface of nano-magnesium oxide, and the long-chain alkyl group of stearic acid is grafted onto the surface of nano-magnesium oxide, thereby improving the compatibility of nano-magnesium oxide with the raw materials of the insulating layer. In addition, the stearic acid molecules can also be physically adsorbed on the surface of nano-magnesium oxide through van der Waals forces, further improving the dispersibility of nano-magnesium oxide and the raw materials of the insulating layer, thereby improving the heat dissipation and insulation properties of the overhead parallel bundled conductors.

[0018] Preferably, the mass ratio of the nano-magnesium oxide to stearic acid is 1:(0.5-1.5).

[0019] By adopting the above technical solution and adjusting the mass ratio of nano-magnesium oxide to stearic acid, the modification effect of stearic acid can be further improved, thereby improving the heat dissipation and insulation properties of the overhead parallel bundled conductors.

[0020] Preferably, the insulating layer further includes sheet-shaped aluminum nitride.

[0021] By adopting this technical solution, flake aluminum nitride is added to the insulation layer, and flake boron nitride can be embedded in the gaps between the aluminum nitride flake layers. The complementary structures form a continuous thermal conductivity network, further improving the heat dissipation of the aluminum nitride flakes. In addition, the difference in dielectric constant between the aluminum nitride flakes and the boron nitride flakes can form a gradient distribution, further improving the heat dissipation and insulation properties of the overhead parallel bundled conductors.

[0022] Preferably, the weight ratio of the flaky aluminum nitride to the flaky boron nitride is 1:(1-2).

[0023] By adopting the above technical solution and adjusting the weight ratio of flaky aluminum nitride to flaky boron nitride, the heat dissipation and insulation properties of the overhead parallel bundled conductors can be further improved.

[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. By controlling the types and dosages of the various raw materials in the insulation layer, the present application achieves thermal conductivity, volume resistivity at 20°C, and dielectric strength of the overhead parallel bundled conductors of 0.48 W / mk, 2.28-2.31 Ω·cm, and 35 MPa, respectively. The reduction rate of elongation at break after thermal aging is 6.4-6.7%, thereby improving the insulation performance and heat dissipation of the overhead parallel bundled conductors.

[0025] (2) The present application modifies the nano-magnesium oxide in the raw material of the insulating layer and controls the mass ratio of nano-magnesium oxide to stearic acid, so that the thermal conductivity, volume resistivity at 20°C, and dielectric strength of the overhead parallel bundled conductor are 0.51-0.52 W / mk, 2.37-2.40 Ω·cm, and 37 MPa, respectively. The reduction rate of elongation at break after thermal aging is 5.8-6.1%, thereby further improving the insulation performance and heat dissipation of the overhead parallel bundled conductor.

[0026] (3) The present application adds flaky aluminum nitride to the insulating layer raw material and adjusts the weight ratio of flaky aluminum nitride to flaky boron nitride, so that the thermal conductivity, volume resistivity at 20°C, and dielectric strength of the overhead parallel bundled conductor are 0.58-0.60 W / mk, 2.47-2.56 Ω·cm, and 40 MPa, respectively, and the reduction rate of elongation at break after thermal aging is 5.0-5.3%, thereby further improving the insulation performance and heat dissipation of the overhead parallel bundled conductor. DETAILED DESCRIPTION

[0027] The present application is further described in detail below with reference to specific embodiments.

[0028] The following raw materials in this application are all commercially available products. They are provided for the purpose of ensuring full disclosure of the raw materials in this application and should not be construed as limiting the sources of the raw materials. Specifically, they include: cross-linked polyethylene (Unica Japan, HFDJ-4201S MI3), purchased from Shanghai Oushuo Plastics Co., Ltd.; antioxidant, model 1010; UV absorber, model UV384-2, with an active ingredient content of 95%; nano-magnesium oxide, particle size 50 nm; methyl vinyl silicone rubber, vinyl content 0.16%, active ingredient content 98%; flake boron nitride, flake diameter 1-3 μm, average thickness <100 nm; silane coupling agent, model KH550; stearic acid, with an active ingredient content of 99%; and flake aluminum nitride, flake diameter 1-3 μm, average thickness <100 nm.

[0029] The following is an example of the preparation of modified nano-magnesium oxide Preparation Example 1 The modified nano-magnesium oxide of Preparation Example 1 was prepared by the following steps: S1. Add 0.3 kg of stearic acid to 75% ethanol solution, stir and heat to 70°C to make a stearic acid solution with a concentration of 15%; S2. Dry 1 kg of nano-magnesium oxide at 110°C for 3 hours, add it to the stearic acid solution, stir at 700 rpm, ultrasonically disperse for 20 minutes, ultrasonic power 400 W, heat to 90°C, stir and react at constant temperature for 3 hours, cool, filter, wash, and vacuum dry to obtain modified nano-oxidase.

[0030] Preparation Example 2-5 The preparation methods of the modified silicon nitride of Preparation Examples 2-5 are the same as that of Preparation Example 1, except that the amounts of stearic acid used are 0.5 g, 1 kg, 1.5 kg and 1.6 kg, respectively. The types and amounts of other raw materials are the same as those of Preparation Example 1.

[0031] Example 1 The overhead parallel bundled conductors of Example 1 are prepared by the following preparation method: According to the dosage in Table 1, the raw materials of the insulating layer were mixed at 120°C for 15 minutes, extruded (the temperature of the first zone was 150°C, the temperature of the second zone was 170°C, and the temperature of the third zone was 160°C), and vulcanized at 140°C for 10 minutes to obtain the insulating layer material; Aluminum monofilaments are drawn and annealed, and then twisted to form conductors. Insulation layer material is extruded and coated on the surface of the conductors, and irradiated for cross-linking for 2-4 hours. Adjacent conductors are fixedly connected to each other by connecting ribs to obtain overhead parallel bundled conductors.

[0032] Examples 2-5 The overhead parallel bundled conductors of Examples 2-5 are the same as those of Example 1, except that the dosage of the raw materials in the insulation layer is different, as shown in Table 1.

[0033] Table 1 Amount of each raw material added to the insulation layer of Examples 1-5 (kg) Examples 6-10 The overhead parallel bundled conductors of Examples 6-10 are the same as those of Example 1, except that the dosage of the raw materials in the insulation layer is different, as shown in Table 2.

[0034] Table 2 Amount of each raw material added to the insulation layer of Examples 1-5 (kg) Examples 11-15 The preparation methods of the overhead parallel bundled conductors of Examples 11-15 are the same as those of Example 8, except that the nano-magnesium oxide is the modified nano-magnesium oxide prepared in Preparation Examples 1-5, and the types and dosages of the other raw materials are the same as those of Example 8.

[0035] Examples 16-20 The preparation methods of the overhead parallel bundled conductors of Examples 16-20 are the same as those of Example 13, except that the raw materials for the insulating layer further include flaky aluminum nitride, and the amounts of flaky aluminum nitride used are 12 kg, 6 kg, 4 kg, 3 kg, and 2.4 kg, respectively. The types and dosages of the remaining raw materials are the same as those of Example 13.

[0036] Comparative Example 1 The overhead parallel bundled conductors of Comparative Example 1 are the same as those of Example 1, except that nano magnesium oxide is not added to the insulating layer. The types and amounts of other raw materials are the same as those of Example 1.

[0037] Comparative Example 2 The overhead parallel bundled conductors of Comparative Example 2 are the same as those of Example 1, except that methyl vinyl silicone rubber is not added to the insulation layer. The types and amounts of other raw materials are the same as those of Example 1.

[0038] Comparative Example 3 The overhead parallel bundled conductor of Comparative Example 3 is the same as that of Example 1, except that no flake boron nitride is added to the insulating layer. The other raw material types and dosages are the same as those of Example 1.

[0039] Performance test (I) The performance of the overhead parallel bundled conductors obtained in different Examples 1-20 and Comparative Examples 1-3 was tested respectively. The test results are shown in Table 3.

[0040] Thermal conductivity: The thermal conductivity of the insulation layer of overhead parallel bundled conductors is tested in accordance with GB / T 10297-1998 "Determination of thermal conductivity of non-metallic solid materials - Hot wire method".

[0041] Retention rate after heat aging: Aging test is carried out according to GB / T2951.12-2008 to detect the reduction rate of elongation at break of the insulation layer of overhead parallel bundled conductors after heat aging.

[0042] Volume resistivity at 20℃: The volume resistivity at 20℃ of the insulation layer of overhead parallel bundled conductors is tested according to GB / T1410 standard.

[0043] Dielectric strength: Refer to GB / T1409 standard to test the dielectric strength of the insulation layer of overhead parallel bundled conductors.

[0044] Table 3 Performance test results of different overhead parallel bundled conductors The test results in Table 3 show that the thermal conductivity of the overhead parallel bundled conductor obtained in this application is as high as 0.60 W / mk, and the reduction rate of elongation at break after thermal aging is as low as 5.0%, which improves the heat dissipation of the overhead parallel bundled conductor. The volume resistivity and dielectric strength at 20°C are as high as 2.56×10 14 Ω·cm and 40kV / mm, which improves the insulation performance of overhead parallel bundled conductors.

[0045] Combined with the performance test data of the overhead parallel bundled conductors of Examples 1-5, it can be seen that the thermal conductivity, 20°C volume resistivity, and dielectric strength of the overhead parallel bundled conductors of Examples 2-4 are 0.4-0.3 W / mk, 2.15-2.22 Ω·cm, and 32-33 MPa, respectively, which are all higher than those of Example 1 and Example 5. The reduction rate of elongation at break after thermal aging is 7.0-7.3%, which is lower than that of Example 1 and Example 5. This shows that when the weight ratio of nano-magnesium oxide to methyl vinyl silicone rubber in the insulating layer raw material is 1:(2-4), it is more suitable, which improves the insulation performance and heat dissipation of the overhead parallel bundled conductors.

[0046] Combined with the performance test data of the overhead parallel bundled conductors of Examples 6-10, it can be seen that the thermal conductivity, 20°C volume resistivity, and dielectric strength of the overhead parallel bundled conductors of Examples 7-9 are 0.48 W / mk, 2.28-2.31 Ω·cm, and 35 MPa, respectively, which are all higher than those of Example 6 and Example 10. The reduction rate of elongation at break after thermal aging is 6.4-6.7%, which is lower than that of Example 6 and Example 10. This shows that when the weight ratio of nano-magnesium oxide to flake boron nitride in the insulating layer raw material is 1:(1.3-1.7), it is more suitable, which improves the insulation performance and heat dissipation of the overhead parallel bundled conductors.

[0047] Combined with the performance test data of the overhead parallel bundled conductors of Examples 11-15, it can be seen that the thermal conductivity, volume resistivity at 20°C, and dielectric strength of the overhead parallel bundled conductors of Examples 12-14 are 0.51-0.52 W / mk, 2.37-2.40 Ω·cm, and 37 MPa, respectively, which are all higher than those of Example 11 and Example 15, and the reduction rate of elongation at break after thermal aging is 5.8-6.1%, which is lower than that of Example 11 and Example 15. This shows that when the nano-zinc oxide is modified, a mass ratio of nano-magnesium oxide to stearic acid of 1:(0.5-1.5) is more suitable, which improves the insulation performance and heat dissipation of the overhead parallel bundled conductors.

[0048] Combined with the performance test data of the overhead parallel bundled conductors of Examples 16-20, it can be seen that the thermal conductivity, 20°C volume resistivity, and dielectric strength of the overhead parallel bundled conductors of Examples 17-19 are 0.58-0.60 W / mk, 2.47-2.56 Ω·cm, and 40 MPa, respectively, which are all higher than those of Example 6 and Example 10. The reduction rate of elongation at break after thermal aging is 5.0-5.3%, which is lower than that of Example 6 and Example 10. This shows that adding flaky aluminum nitride to the insulating layer raw material and a weight ratio of flaky aluminum nitride to flaky boron nitride of 1:(1-2) are more suitable, thereby improving the insulation performance and heat dissipation of the overhead parallel bundled conductors.

[0049] In addition, based on the performance test data of the overhead parallel bundled conductors of Comparative Examples 1-3 and Example 1, it was found that adding nano-magnesium oxide, methyl vinyl silicone rubber and flaky boron nitride to the raw materials of the insulation layer of the overhead parallel bundled conductors can improve the insulation performance and heat dissipation of the overhead parallel bundled conductors to varying degrees.

[0050] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. An overhead parallel bundled conductor, characterized in that: It comprises at least two conductors arranged side by side, and adjacent conductors are fixedly connected to each other via connecting ribs; an insulating layer is provided on the outer wall of the conductor; The insulating layer comprises the following raw materials in parts by weight: 80-100 parts of cross-linked polyethylene, 0.5-1 part of antioxidant, 0.5-1 part of ultraviolet absorber, 3-5 parts of nano magnesium oxide, 5-15 parts of methyl vinyl silicone rubber, 4-10 parts of flaky boron nitride and 1-2 parts of silane coupling agent.

2. The overhead parallel bundled conductor according to claim 1, characterized in that: The insulating layer comprises the following raw materials in parts by weight: 85-95 parts of cross-linked polyethylene, 0.7-0.9 parts of antioxidant, 0.7-0.9 parts of ultraviolet absorber, 3.5-4.5 parts of nano magnesium oxide, 8-12 parts of methyl vinyl silicone rubber, 5-7 parts of flaky boron nitride, and 1.3-1.8 parts of silane coupling agent.

3. The overhead parallel bundled conductor according to claim 1, characterized in that: The weight ratio of the nano magnesium oxide to the methyl vinyl silicone rubber is 1:(2-4).

4. The overhead parallel bundled conductor according to claim 1, characterized in that: The weight ratio of the nano magnesium oxide to the flaky boron nitride is 1:(1.3-1.7).

5. The overhead parallel bundled conductor according to claim 1, characterized in that: The nano magnesium oxide is prepared by modification, specifically: S1. Add stearic acid to 75% ethanol solution, stir and heat to 60-80°C to prepare a stearic acid solution with a concentration of 10-20%; S2. Dry the nano-magnesium oxide at 100-120°C for 2-4 hours, add it to the stearic acid solution, stir at 600-800 rpm, ultrasonically disperse for 15-30 minutes, and use an ultrasonic power of 300-500 W. Heat to 80-100°C, stir and react at a constant temperature for 2-4 hours, cool, filter, wash, and vacuum dry to obtain the modified nano-oxidase.

6. The overhead parallel bundled conductor according to claim 5, characterized in that: The mass ratio of the nano magnesium oxide to stearic acid is 1:(0.5-1.5).

7. The overhead parallel bundled conductor according to claim 1, characterized in that: The insulating layer also includes sheet-shaped aluminum nitride.

8. The overhead parallel bundled conductor according to claim 7, characterized in that: The weight ratio of the flaky aluminum nitride to the flaky boron nitride is 1:(1-2).

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