Self-cooling overhead bare conductor

Abstract

A self-cooling overhead bare conductor relates to the technical field of power transmission equipment and structurally comprises a conductor substrate, a graphene coating used for radiating heat is arranged on a backlight surface of the conductor substrate, and the coverage range of the graphene coating in the circumferential direction of the conductor substrate is 120-180 degrees. The graphene coating is arranged in a segmented mode in the length direction of the wire base body, the length of each segment of the graphene coating is 5 / 3-2 times of the diameter of the wire base body, and the distance between every two adjacent segments of the graphene coating is 0.85-1 time of the diameter of the wire base body. Sand blasting treatment is carried out on the joint face of the wire base body and the graphene coating, the surface roughness is Ra3.2-6.3 microns, oxidation films and impurities on the surface of the wire base body are removed, the adhesive force of the graphene coating is enhanced, and the thickness of the graphene coating is 40-80 microns. According to the invention, the technical problem of current limiting caused by temperature rise of the wire can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power transmission equipment, in particular to a self-cooling overhead bare conductor. BACKGROUND

[0002] In the process of extra-high voltage long-distance power transmission, the overhead bare conductor may cause current limiting due to the increase of resistance caused by temperature rise. The existing technology currently does not have a technical solution to realize conductor cooling by improving the structure of the conductor. SUMMARY

[0003] The purpose of the present application is to provide a self-cooling overhead bare conductor, which can solve the technical problem of current limiting caused by temperature rise of the conductor.

[0004] In order to achieve the above purpose, the present application adopts the following technical solutions.

[0005] A self-cooling overhead bare conductor, comprising a conductor base body, the conductor base body is provided with a graphene coating for radiating heat on the backlit side.

[0006] The graphene coating is arranged in sections along the length direction of the conductor base body.

[0007] Further, the coverage range of the graphene coating in the circumferential direction of the conductor base body is 120°-180°.

[0008] Further, the length of each section of the graphene coating is 5 / 3-2 times the diameter of the conductor base body, and the spacing between the adjacent two sections of the graphene coating is 0.85-1 times the diameter of the conductor base body.

[0009] Further, the joint surface of the graphene coating on the conductor base body is subjected to sandblasting treatment, and the surface roughness is Ra3.2-6.3μm, which is used to remove the oxide film and impurities on the surface of the conductor base body and enhance the adhesion of the graphene coating.

[0010] Further, the graphene coating is formed by coating graphene coating on the conductor base body, and the graphene coating is prepared by compounding graphene and high-temperature resistant resin, wherein the mass fraction of graphene is 15%-20%.

[0011] Further, the thickness of the graphene coating is 40-80μm.

[0012] After adopting the above technical solutions, the present application has the following beneficial effects: 1. The present application sets the graphene coating on the backlit side of the conductor base body in sections, uses the graphene coating to radiate energy to the surrounding environment with lower relative temperature, heats and warms the air near the graphene coating, not only generates vertical air convection, but also generates convection along the axis direction of the conductor, so as to use the air to take away the heat of the conductor and achieve the purpose of cooling the conductor. 2、The graphene coating is arranged at intervals on the back light surface of the conductor base body, the graphene coating is reserved with heat expansion space in the radial direction and the circumferential direction of the conductor base body, and the problem of coating falling off due to the difference in the thermal expansion coefficient between the conductor and the graphene coating is avoided. 3、The graphene coating is arranged at intervals on the back light surface of the conductor base body, compared with full coating, the cost is reduced, and the overall quality is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0013] Fig. 1 is a schematic view of the circumferential distribution range of the graphene coating on the conductor base body.

[0014] Fig. 2 is a schematic view of the segmented distribution state of the graphene coating on the conductor base body in the axial direction.

[0015] BRIEF DESCRIPTION OF DRAWINGS: 1, conductor base body, 2, graphene coating. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical scheme and advantages of the present application more clear, the characteristics and performance of the self-cooling overhead bare conductor are further described in detail below in combination with the drawings and examples.

[0017] Please refer to the accompanying Figs. 1-2 A self-cooling overhead bare conductor, comprising a conductor base body 1.

[0018] The conductor base body 1 is provided with a graphene coating 2 for radiating heat on the back light surface, and the graphene coating 2 is arranged in segments along the length direction of the conductor base body 1.

[0019] Specifically, the coverage range of the graphene coating 2 in the circumferential direction of the conductor base body 1 is 120°-180°. The length of each segment of the graphene coating 2 is 4 / 3-2 times the diameter of the conductor base body 1, and the interval between the adjacent two segments of the graphene coating 2 is 0.85-1 times the diameter of the conductor base body 1. As a preferred, in the present embodiment, the coverage range of the graphene coating 2 in the circumferential direction of the conductor base body 1 is 120°, the length of each segment of the graphene coating 2 is 2 times the diameter of the conductor base body 1, and the interval between the adjacent two segments of the graphene coating 2 is 1 times the diameter of the conductor base body 1.

[0020] The bonding surface of the conductor base 1 and the graphene coating 2 is subjected to sand blasting treatment, and the surface roughness is Ra 3.2-6.3 μm, which is used to remove the oxide film and impurities on the surface of the conductor base 1 and to enhance the adhesion of the graphene coating. The graphene coating 2 is formed by applying graphene coating on the conductor base 1, and the graphene coating is prepared by compounding graphene and high-temperature-resistant resin, wherein the mass fraction of graphene is 15%-20%. The thickness of the graphene coating 2 is 40-80 μm. As preferred, in the embodiment, the mass fraction of graphene in the graphene coating is 18%, and the thickness of the graphene coating 2 is 60 μm.

[0021] In the implementation, the self-cooling overhead bare conductor in the application is a new type of conductor in which a graphene coating is coated on the back surface of a conventional bare conductor (mainly made of aluminum or aluminum alloy) at a certain distance.

[0022] According to the Stefan-Boltzmann law, the radiation energy of an object is proportional to the fourth power of the surface gray coefficient and the temperature of the object, that is: wherein ε is the surface gray coefficient of the object, and T is the temperature of the object.

[0023] The surface gray coefficients of graphene coating and aluminum in the infrared band are ε 石墨烯涂层 ≈0.85-0.95 and ε 铝 ≈0.2-0.4, respectively. Therefore, when the temperature T of the conductor rises, the area of the conductor provided with the graphene coating will radiate more energy to the surrounding environment with a relatively lower temperature, resulting in the air temperature difference near the conductor to form convection, thereby transferring heat to the low-temperature area (chimney effect) to achieve the purpose of cooling the conductor.

[0024] The conductor base 1 is usually selected from high-strength electrical aluminum conductors, and in the embodiment, the LGJ-400 / 35 type steel core aluminum stranded wire is taken as an example to illustrate the scheme. Aluminum has good electrical conductivity and ductility, and has small density, which is suitable for long-distance power transmission. The steel core can improve the mechanical strength of the conductor and prevent the conductor from being broken due to gravity, wind force and other factors.

[0025] The graphene coating 2 covers an area of 120° in the circumferential direction of the conductor base 1, as shown in Fig. 1 The graphene coating 2 is preferentially directed to the ground and the sky low-temperature area to avoid the influence of oblique sun radiation on heat dissipation. In addition, the back surface during the erection of the conductor is not determined by the upper and lower directions in the vertical direction, but is related to the latitude of the erection site. The back surface is the surface facing away from the sun with the connecting line between the center of the conductor and the sun on the summer solstice as the axis.

[0026] The position of the conductor base 1 provided with the graphene coating 2 needs to be pretreated, and the surface oxide film and impurities are removed by sand blasting process, and the surface roughness is controlled to be Ra 3.2-6.3 μm to enhance the adhesion of the graphene coating 2.

[0027] The graphene coating 2 is arranged in stripes along the length direction of the conductor substrate 1, such as Fig. 2 The length of each section of graphene coating 2 is twice the diameter of the wire substrate 1, and the distance between two adjacent sections of graphene coating 2 is once the diameter of the wire substrate 1.

[0028] The diameter D of the LGJ-400 / 35 steel-core aluminum stranded wire is 26.82 mm. Therefore, the length d1 of each graphene coating section 2 is 53.64 mm, and the spacing d2 between adjacent graphene coating sections 2 is 26.82 mm. In practical applications, CFD (computational fluid dynamics) simulations of air flow and temperature distribution at different separation distances for different conductor diameters were used to optimize separation distances, break up the boundary layer, and enhance air turbulence for optimal convection. Actual experiments were also conducted to verify the results.

[0029] The graphene coating 2 is formed by applying a graphene coating to the conductor substrate 1. The graphene coating is prepared by combining high-purity graphene (purity ≥99%) with a high-temperature-resistant resin (such as polyimide resin). The graphene is dispersed in the resin in a flake structure, with a content of 18% (mass fraction). The polyimide resin has excellent high-temperature resistance (long-term operating temperature up to 260°C) and good insulation properties, which protect the graphene and ensure the coating's stable operation in high-temperature environments. Appropriate amounts of a dispersant (such as sodium hexametaphosphate) and a coupling agent (such as silane coupling agent KH-550) can be added to the coating to improve the graphene's dispersion in the resin and its adhesion to the aluminum substrate.

[0030] The thickness of graphene coating 2 is 60 μm. In practical applications, coating thickness is adjusted based on the graphene additives. Too thin a coating will not significantly improve its thermal conductivity and radiation performance. Too thick a coating will increase coating costs and wire weight, and may also affect the coating's adhesion and flexibility. A wet film thickness gauge is used to monitor the coating process in real time to ensure uniform coating thickness.

[0031] At the same time, because graphene has excellent thermal conductivity, its thermal conductivity coefficient is as high as 5300W / (m·K), which is much higher than the 237W / (m·K) of aluminum. It can transfer heat quickly and will not significantly affect the heat dissipation of the wire at room temperature due to coating.

[0032] It should be noted that the parts not described in detail in this solution are all prior art, and the above embodiments are only used to illustrate the present invention, but the present invention is not limited to the above embodiments. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention fall within the scope of protection of the present invention.

Claims

1. A self-cooling overhead bare conductor, characterized by: The invention comprises a conductor substrate (1), wherein the conductor substrate (1) is provided with a graphene coating (2) for radiating heat on a side facing away from light. The graphene coating (2) is arranged in sections along the length direction of the wire substrate (1).

2. The self-cooling overhead bare conductor according to claim 1, characterized in that: The coverage range of the graphene coating (2) on the circumferential direction of the conductor substrate (1) is 120° to 180°.

3. The self-cooling overhead bare conductor according to claim 1, characterized in that: The length of each section of graphene coating (2) is 5 / 3 to 2 times the diameter of the conductor substrate (1), and the distance between two adjacent sections of graphene coating (2) is 0.85 to 1 times the diameter of the conductor substrate (1).

4. The self-cooling overhead bare conductor according to claim 1, characterized in that: The bonding surface between the conductor substrate (1) and the graphene coating (2) is sandblasted to a surface roughness of Ra3.2 to 6.3 μm, for removing oxide films and impurities on the surface of the conductor substrate (1) and enhancing the adhesion of the graphene coating.

5. The self-cooling overhead bare conductor according to claim 1, characterized in that: The graphene coating (2) is formed by coating a graphene coating on a conductor substrate (1), wherein the graphene coating is prepared by compounding graphene and a high-temperature resistant resin, wherein the mass fraction of the graphene is 15% to 20%.

6. The self-cooling overhead bare conductor according to claim 5, characterized in that: The thickness of the graphene coating (2) is 40 to 80 μm.

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