High-heat-dissipation conductor structure for realizing efficient heat dissipation of vacuum arc-extinguishing chamber and preparation method and application of high-heat-dissipation conductor structure

Abstract

The invention discloses a high-heat-dissipation conductor structure capable of achieving efficient heat dissipation of a vacuum arc-extinguishing chamber and a preparation method and application of the high-heat-dissipation conductor structure, and belongs to the technical field of vacuum arc-extinguishing chambers. The high-heat-dissipation conductor structure sequentially comprises a conductor base body, a NiCr base layer and a ceramic layer from bottom to top, and the surface of the conductor base body is a rough surface layer; the thickness of the NiCr base layer is 30 microns, the ceramic layer comprises the following components in percentage by mass: 5% of aluminum oxide ceramic powder and 95% of aluminum nitride ceramic powder, the purities of the aluminum oxide ceramic powder and the aluminum nitride ceramic powder are respectively greater than 99.9%, the particle sizes of the aluminum oxide ceramic powder and the aluminum nitride ceramic powder are respectively 75-100 microns, and the thickness of the ceramic layer is 150 microns. The high-heat-dissipation conductor structure for the vacuum arc extinguish chamber is provided for the first time, efficient heat dissipation of the arc extinguish chamber can be achieved under the condition that the structure and motion characteristics of the vacuum arc extinguish chamber are not changed, the through-current capacity of the arc extinguish chamber is improved, the operation reliability of a high-capacity vacuum switch is guaranteed, and rapid engineering application of the high-capacity switch is promoted.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vacuum arc-extinguishing chamber, in particular to a high-heat-dissipation conductor structure for realizing efficient heat dissipation of vacuum arc-extinguishing chamber and a preparation method and application thereof. BACKGROUND

[0002] A vacuum circuit breaker is named as such because the insulating medium before and after arc extinction is high vacuum, and has the advantages of small size, light weight, frequent operation, maintenance-free, etc., so developing a large-capacity vacuum breaking type switch device is the only effective way to completely replace SF6 in the high-voltage field at the present stage. The temperature rise of a vacuum circuit breaker depends on the heat generation and heat dissipation during operation, and the heat generated during the long-term current flow of a vacuum arc-extinguishing chamber is only transmitted outward through the dynamic conductor rod and the static side contact surface, resulting in the accumulation of heat in the dynamic and static conductors outside the vacuum arc-extinguishing chamber, which affects the current flow capacity and service life during the operation of the circuit breaker.

[0003] Due to the fact that the vacuum environment cannot conduct heat, the heat dissipation capacity of the vacuum arc-extinguishing chamber is extremely poor, and most of the heat generated is transferred to the gas inside the circuit breaker through the dynamic side and static side conductors to achieve heat dissipation. The single heat dissipation channel and poor gas circulation result in poor heat dissipation effect, and the heat is easily accumulated in the dynamic side and static side conductors outside the vacuum arc-extinguishing chamber, resulting in high temperature rise during the current flow of the circuit breaker, which is difficult to meet the rated current flow requirement.

[0004] Improving the heat dissipation capacity of the vacuum arc-extinguishing chamber for the circuit breaker is crucial for improving the current flow capacity of the circuit breaker. The most direct means is to install a heat sink on the dynamic and static conductors of the vacuum arc-extinguishing chamber to dissipate the heat conducted out of the arc-extinguishing chamber through the heat sink, avoiding the accumulation of a large amount of heat on the dynamic and static conductors. Domestic and foreign scholars have explored and researched the feasibility of installing a heat sink on the vacuum arc-extinguishing chamber. For example, Yu Wei et al. used the original variable numerical analysis method to study the influence of thermal and material diffusion buoyancy on fluid mechanics and heat and mass transfer in a vertical plane; Cheng and Bazylak et al. studied the natural convection characteristics in a closed cavity. A large number of studies have shown that the external heat sink installed on the dynamic and static ends of the vacuum arc-extinguishing chamber is expected to manage the heat of the vacuum arc-extinguishing chamber, reduce the heat accumulation of the vacuum arc-extinguishing chamber, and improve the current flow capacity. However, due to the structure of the vacuum arc-extinguishing chamber and the motion characteristics of the circuit breaker, the weight and structure of the heat sink are strictly limited, the structural design is extremely complex, and the reliability of the product is also affected.

[0005] As the "heart" of a vacuum circuit breaker, the performance of the vacuum interrupter directly determines the electrical life of the circuit breaker and the safe operation of the power grid. Due to the high vacuum environment and structural characteristics of the vacuum interrupter, most of the heat is conducted along the moving and stationary conductors. This results in few heat dissipation paths, poor gas flow, and low conduction efficiency. Furthermore, the circuit breaker's current-carrying process is a continuous heat dissipation process, causing heat to easily accumulate in large quantities on the moving and stationary conductors outside the interrupter. This leads to excessive temperature rise during current flow, making it difficult to meet the rated current requirements.

[0006] Therefore, there is an urgent need to develop a method to accelerate the high-radiation heat dissipation of conductor components in a vacuum-sealed environment, improve the heat dissipation capacity of the vacuum interrupter, and avoid the reduction in the current-carrying capacity of the circuit breaker caused by the large accumulation of heat on the conductor. Summary of the Invention

[0007] In view of this, the present invention provides a high heat dissipation conductor structure for achieving efficient heat dissipation in a vacuum interrupter, its preparation method, and its application.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A high heat dissipation conductor structure for achieving efficient heat dissipation in a vacuum interrupter, comprising, from bottom to top: a conductor substrate, a NiCr underlayer, and a ceramic layer, wherein the surface of the conductor substrate is a rough surface layer; The thickness of the NiCr base layer is 25-30 μm, and the mass percentage of each component in the ceramic layer is: 5% alumina ceramic powder, 95% aluminum nitride ceramic powder, the purity of alumina ceramic powder and aluminum nitride ceramic powder are >99.9% respectively, the particle size is 75-100 μm respectively, and the thickness of the ceramic layer is 130-160 μm.

[0009] Furthermore, the conductor substrate is a copper substrate.

[0010] This invention also provides a method for preparing the high heat dissipation conductor structure for achieving efficient heat dissipation in a vacuum interrupter, characterized by comprising the following steps: (1) A rough surface layer is formed by sandblasting the surface of the conductor substrate; (2) A layer of NiCr is sprayed onto the surface of the rough layer using thermal spraying as a base layer; (3) A ceramic layer is sprayed onto the surface of the NiCr base layer by thermal spraying to obtain the high heat dissipation conductor structure that achieves efficient heat dissipation of the vacuum interrupter.

[0011] Furthermore, in step (1), the surface of the conductor substrate is sandblasted using 40-mesh white corundum abrasive particles.

[0012] Furthermore, in step (2), a NiCr layer is sprayed onto the surface of the rough layer using plasma spraying as the NiCr base layer. The thickness of each spray layer is 1-2 mils, i.e. 0.01-0.02mm.

[0013] Furthermore, in step (2), after each coat of coating, compressed air is used to blow the coating to cool it down before spraying again, and the temperature of the conductor substrate is controlled to be 80-120℃. The operation is repeated until the NiCr base coat thickness reaches 30μm.

[0014] Furthermore, in step (3), a ceramic layer is sprayed onto the surface of the NiCr base layer using plasma spraying, with each layer having a thickness of 2-3 mils, i.e., 0.02-0.03mm.

[0015] Furthermore, in step (3), after each spraying, the coating is cooled down by blowing with compressed air before spraying again, and the temperature of the conductor substrate is controlled at 80-120℃. The operation is repeated until the NiCr underlayer thickness reaches 150μm.

[0016] The present invention also provides an application of the high heat dissipation conductor structure or the high heat dissipation conductor structure prepared by the method in the preparation of the moving and stationary end conductors of a vacuum interrupter.

[0017] Beneficial effects of this invention: 1. To improve the heat dissipation capacity of the conductor in a vacuum interrupter, this invention proposes to prepare a conductor structure with an aluminum nitride / alumina ceramic coating on the conductor surface, which has high thermal conductivity and high radiation heat dissipation performance.

[0018] 2. The ceramic coating is applied to the surface of the copper-based conductor using a thermal spraying method. To achieve good bonding strength between the coating and the conductor, the conductor substrate material is first sandblasted to form a rough surface layer. Then, a NiCr underlayer that can form a micro-metallurgical bond with the substrate is sprayed between the rough surface layer and the ceramic coating. The bonding force between the conductor substrate and the ceramic layer is greater than 30 MPa.

[0019] 3. Aluminum nitride ceramics possess excellent thermal conductivity, high-temperature insulation, low dielectric constant, high melting point, high hardness, low coefficient of thermal expansion, and high thermal radiation performance, making them an ideal material for next-generation heat dissipation substrates in the electronics field. By spraying a high-radiation heat-dissipating ceramic coating onto the surfaces of the moving and stationary conductors in a vacuum interrupter, heat from the conductor surface first reaches the coating surface through conduction. Relying on the combined effects of the coating's thermal conductivity and radiation, heat is rapidly dissipated, lowering the surface and internal temperature of the object, ultimately achieving the purpose of cooling and heat dissipation. This can solve the problem of poor heat dissipation performance in vacuum interrupters and improve their flow capacity without changing the structure and motion characteristics of the vacuum interrupter. To obtain a high-quality aluminum nitride ceramic coating, aluminum nitride and alumina ceramic powders with a purity >99.9%, a particle size of 75–100 μm, and a coating thickness of approximately 0.15 mm are selected, resulting in superior bonding strength and heat dissipation performance.

[0020] Temperature rise tests were conducted on conductors with and without aluminum nitride coatings under vacuum conditions and a current of 2500A to verify the effect of the aluminum nitride coating on the heat dissipation performance of the conductors. The test results showed that under the same test conditions, the temperature rise values ​​of the inner and outer surfaces of the uncoated conductor were 69.9K and 72.7K, respectively, while the temperature rise values ​​of the inner and outer surfaces of the conductor with aluminum nitride coating were 56.1K and 60.2K, respectively. Due to the good thermal conductivity and radiation effect of the aluminum nitride coating, the temperature rise value can be reduced by about 13K and the heat dissipation efficiency can be increased by about 18%. This can significantly improve the heat dissipation performance and current carrying capacity of the vacuum interrupter, and strongly support the development of high-voltage and high-current vacuum circuit breakers.

[0021] This invention proposes for the first time a high heat dissipation conductor structure for vacuum interrupters, which can achieve efficient heat dissipation of the interrupter without changing its structure and motion characteristics, improve its current carrying capacity, ensure the operational reliability of large-capacity vacuum switches, and promote the rapid engineering application of large-capacity switches. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the high heat dissipation conductor structure of the present invention.

[0023] Figure 2 This is a microstructure diagram of the high heat dissipation conductor of the present invention. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1 A high heat dissipation conductor structure for achieving efficient heat dissipation in a vacuum interrupter is provided. The high heat dissipation conductor structure comprises, from bottom to top, a conductor substrate, a NiCr underlayer, and a ceramic layer. The surface of the conductor substrate is a rough surface layer. The NiCr base layer has a thickness of 30 μm. The mass percentage of each component in the ceramic layer is as follows: 5% alumina ceramic powder, 95% aluminum nitride ceramic powder, with the purity of alumina ceramic powder and aluminum nitride ceramic powder being >99.9% and the particle size being 75-100 μm respectively. The thickness of the ceramic layer is 150 μm.

[0026] A method for fabricating a high-heat-dissipation conductor structure to achieve efficient heat dissipation in a vacuum interrupter includes the following steps: (1) Inspect the condition of the copper substrate to ensure that the dimensions meet the requirements of the drawings and that there are no defects such as bumps or scratches on the surface; (2) Before sandblasting, clean the surface of the copper substrate with alcohol to remove surface oil and attachments. Then, put it into the sandblasting machine and use 40-mesh white corundum abrasive to sandblast the surface of the copper substrate to remove the oxide layer and form a rough surface. Ensure that the sandblasting surface is uniform and there are no un-sandblasted areas. (3) Before spraying, use high-pressure compressed air to clean the copper substrate and remove foreign matter from the surface to ensure the cleanliness of the spraying surface. Use plasma spraying to spray a NiCr layer on the rough surface as the NiCr base layer. The thickness of each spray is 1-2 mils, i.e. 0.01-0.02mm. After each spray, blow the coating with compressed air to cool it down before spraying again. In order to control the deformation of the workpiece and the coating peeling off, control the temperature of the conductor substrate to 80-120℃. Repeat the operation until the NiCr base layer thickness reaches 30μm. (4) A ceramic layer is sprayed onto the surface of the NiCr substrate using plasma spraying. Each layer is 2-3 microns thick, i.e., 0.02-0.03 mm. After each layer is sprayed, the coating is cooled by blowing with compressed air before spraying again. The temperature of the conductor substrate is controlled at 80-120℃. The coating should be uniform and dense. The operation is repeated until the thickness of the NiCr substrate reaches 150 μm, thus obtaining a high heat dissipation conductor structure that achieves efficient heat dissipation of the vacuum interrupter.

[0027] Temperature rise tests were conducted on the conductors of Example 1 with ceramic coating and Comparative Example 1 without ceramic coating under vacuum conditions and current of 2500A to verify the effect of aluminum nitride coating on the heat dissipation performance of the conductor. Compared with Example 1, except for the absence of ceramic coating, the other steps and parameters were the same as in Example 1.

[0028] The test results show that under the same test conditions, the temperature rise values ​​of the inner and outer surfaces of the uncoated conductor are 69.9K and 72.7K, respectively, while the temperature rise values ​​of the inner and outer surfaces of the conductor coated with aluminum nitride are 56.1K and 60.2K, respectively. Due to the good thermal conductivity and radiation effect of the aluminum nitride ceramic layer, the temperature rise value can be reduced by about 13K and the heat dissipation efficiency can be increased by about 18%. This can significantly improve the heat dissipation performance and current carrying capacity of the vacuum interrupter, and strongly support the development of high-voltage and high-current vacuum circuit breakers.

[0029] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A high-heat-dissipation conductor structure for achieving efficient heat dissipation in a vacuum interrupter, characterized in that, The high heat dissipation conductor structure comprises, from bottom to top: a conductor substrate, a NiCr underlayer, and a ceramic layer, wherein the surface of the conductor substrate is a rough surface layer; The thickness of the NiCr base layer is 25-30 μm, and the mass percentage of each component in the ceramic layer is: 5% alumina ceramic powder, 95% aluminum nitride ceramic powder, the purity of alumina ceramic powder and aluminum nitride ceramic powder are >99.9% respectively, the particle size is 75-100 μm respectively, and the thickness of the ceramic layer is 130-160 μm.

2. The high heat dissipation conductor structure for achieving efficient heat dissipation in a vacuum interrupter according to claim 1, characterized in that, The conductor substrate is a copper substrate.

3. A method for preparing a high-heat-dissipation conductor structure for achieving efficient heat dissipation in a vacuum interrupter as described in claim 1 or 2, characterized in that, Includes the following steps: (1) A rough surface layer is formed by sandblasting the surface of the conductor substrate; (2) A layer of NiCr is sprayed onto the surface of the rough layer using thermal spraying as a base layer; (3) A ceramic layer is sprayed onto the surface of the NiCr base layer by thermal spraying to obtain the high heat dissipation conductor structure that achieves efficient heat dissipation of the vacuum interrupter.

4. The method for preparing a high-heat-dissipation conductor structure for achieving efficient heat dissipation in a vacuum interrupter according to claim 3, characterized in that, In step (1), the surface of the conductor substrate is sandblasted using 40-mesh white corundum abrasive particles.

5. The method for preparing a high-heat-dissipation conductor structure for achieving efficient heat dissipation in a vacuum interrupter according to claim 3, characterized in that, In step (2), a NiCr layer is sprayed onto the surface of the rough layer using plasma spraying as the NiCr base layer. Each spray layer has a thickness of 1-2 mils, i.e., 0.01-0.02mm.

6. The method for preparing a high-heat-dissipation conductor structure for achieving efficient heat dissipation in a vacuum interrupter according to claim 5, characterized in that, In step (2), after each coat of coating, compressed air is used to blow the coating to cool it down before spraying again. The temperature of the conductor substrate is controlled at 80-120℃. The operation is repeated until the NiCr base coat thickness reaches 30μm.

7. The method for preparing a high-heat-dissipation conductor structure for achieving efficient heat dissipation in a vacuum interrupter according to claim 3, characterized in that, In step (3), a ceramic layer is sprayed onto the NiCr base layer using plasma spraying. Each coat is 2-3 microns thick, or 0.02-0.03 mm.

8. The method for preparing a high-heat-dissipation conductor structure for achieving efficient heat dissipation in a vacuum interrupter according to claim 7, characterized in that, In step (3), after each coat of coating, compressed air is used to blow the coating to cool it down before spraying again. The temperature of the conductor substrate is controlled at 80-120℃. The operation is repeated until the NiCr base coat thickness reaches 150μm.

9. The application of the high heat dissipation conductor structure according to claim 1 or 2 or the high heat dissipation conductor structure prepared by the method according to any one of claims 3-8 in the preparation of the moving and stationary end conductors of a vacuum interrupter.

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