40.5kV medium voltage environmentally friendly gas switchgear temperature field optimization structure and simulation method

Abstract

The application discloses a 40.5kV medium-voltage environmentally-friendly gas switch cabinet temperature field optimization structure and a simulation method. The optimization structure comprises a lower gas tank, a circuit breaker and a circuit breaker connecting row electrically connected with the circuit breaker are arranged in the lower gas tank, an upper gas tank is fixedly arranged above the lower gas tank and forms a sealed gas-filled cavity together with the lower gas tank, a bus is arranged in the upper gas tank, at least one heat-conducting ceramic support is fixedly installed in the inside of the lower gas tank, one end of each heat-conducting ceramic support is connected with the surface of the circuit breaker connecting row, the other end is connected with the inner wall surface of the lower gas tank, and a heat-conducting path is formed between the circuit breaker connecting row and the shell of the lower gas tank. By arranging the high-heat-conducting and high-insulating alumina ceramic support between the circuit breaker connecting row and the shell of the lower gas tank, an efficient heat-conducting path is constructed, heat in a local high-temperature area is rapidly conducted to the cabinet shell and dissipated, and the temperature rise of a key position is obviously reduced.

Description

Technical Field

[0001] This application relates to the field of heat dissipation device technology, and in particular to a temperature field optimization structure and simulation method for a 40.5kV medium-voltage environmentally friendly gas switchgear. Background Technology

[0002] Medium-voltage gas-insulated switchgear has been widely used in power systems due to its compact structure, high reliability, and low maintenance requirements. Traditional gas-insulated switchgear often uses sulfur hexafluoride (SF6) as the insulating medium, utilizing its excellent insulation and arc-extinguishing properties. However, SF6 gas has an extremely high global warming potential, and its emissions have a significant impact on the greenhouse effect.

[0003] Currently, using environmentally friendly gases such as dry air and nitrogen to replace sulfur hexafluoride (SF6) as the insulating medium is one of the main technical approaches for the green transformation of gas-insulated switchgear. However, the physical properties of environmentally friendly gases differ significantly from those of SF6. For example, the thermal conductivity of dry air is about one-tenth that of SF6, and its convective heat transfer efficiency is also much lower than that of SF6.

[0004] This difference leads to a particularly prominent problem of internal heat accumulation in environmentally friendly gas-insulated switchgear under high-current operation. Especially in critical conductive areas such as circuit breaker connection bars and busbar connections, localized overheating zones are easily formed due to high current density and relatively concentrated contact resistance. When the temperature rise exceeds the 75K limit specified in the national standard, it not only accelerates the aging of insulation materials and reduces the service life of the equipment, but may also trigger thermal insulation breakdown accidents, severely restricting the equipment's current-carrying capacity and operational reliability. Summary of the Invention

[0005] The purpose of this invention is to provide a temperature field optimization structure and simulation method for a 40.5kV medium-voltage environmentally friendly gas switchgear, which can significantly reduce the temperature rise of key components.

[0006] The embodiments of the present invention are implemented as follows: Firstly, this application provides a temperature field optimization structure for a 40.5kV medium-voltage environmentally friendly gas switchgear, comprising: The lower air box contains a circuit breaker and a circuit breaker connection bar electrically connected to the circuit breaker. The upper air box is fixedly installed above the lower air box and together with the lower air box forms a sealed inflation cavity. A busbar is installed inside the upper air box. At least one thermally conductive ceramic bracket is fixedly installed inside the lower air box. One end of each thermally conductive ceramic bracket is connected to the surface of the circuit breaker connection bar, and the other end is connected to the inner wall surface of the lower air box, so as to form a thermally conductive passage between the circuit breaker connection bar and the shell of the lower air box.

[0007] In a possible implementation, the thermally conductive ceramic support includes: The cold end of the ceramic support has a flat plate structure and is fixedly attached to the inner wall of the lower air box; The hot end of the ceramic bracket has a flat plate structure and is fixedly attached to the surface of the circuit breaker connection bar. A ceramic support heat-conducting plate is integrally connected between the cold end and the hot end of the ceramic support, and is used to conduct heat from the hot end to the cold end of the ceramic support.

[0008] In a possible implementation, the surface of the ceramic support heat-conducting plate is provided with a plurality of bolt holes; the heat-conducting ceramic support is fastened to the inner wall of the circuit breaker connection bar and the lower gas box respectively by bolts passing through the bolt holes, and an insulating gasket is provided between the bolt and the heat-conducting ceramic support, and / or between the bolt and the circuit breaker connection bar.

[0009] In a possible implementation, there are multiple thermally conductive ceramic supports, which are distributed at intervals along the extension direction of the circuit breaker connection bar; wherein at least one thermally conductive ceramic support is correspondingly disposed in the heat-concentrating area of ​​the circuit breaker connection bar, and the remaining thermally conductive ceramic supports are disposed in other temperature-rising areas of the circuit breaker connection bar.

[0010] In a possible implementation, the thermally conductive ceramic support is integrally sintered from alumina ceramic material, wherein the alumina ceramic material has a thermal conductivity ≥25 W / (m·K), an insulation strength ≥15 kV / mm, and a bending strength ≥300MPA25052709.

[0011] In a possible implementation, the surface roughness Ra of the thermally conductive ceramic support that contacts the circuit breaker connection bar and the inner wall of the lower air box is ≤1.6μm, and thermally conductive silicone grease is applied between the contact surfaces.

[0012] In a possible implementation, both the lower and upper air boxes are rectangular cavity structures, and the length of the lower air box is greater than the length of the upper air box. Heat dissipation fins are provided on the outer wall of the lower air box.

[0013] Secondly, this application provides a simulation design method applied to the aforementioned 40.5kV medium-voltage environmentally friendly gas switchgear temperature field optimization structure, comprising the following steps: Step S1: Construct a three-dimensional geometric model of the thermally conductive ceramic support and its related components. The related components include at least the circuit breaker connection bar as a heat source, the lower air box shell as the final heat dissipation end, and the bolts for connection. Step S2: Set the simulation material parameters, which include at least the thermal conductivity, density, constant pressure heat capacity, dielectric strength of the ceramic material, and the equivalent contact thermal resistance at the bolt connection. Step S3: Establish a physical field coupling simulation model in the finite element simulation software, import the three-dimensional geometric model, and set boundary conditions; the boundary conditions include at least the Joule heat loss power of the circuit breaker connection bar, the pressure and convective heat transfer coefficient of the environmentally friendly gas inside the gas box, and the convective heat transfer coefficient between the gas box shell and the external environment. Step S4: Run simulation calculations to obtain the temperature field distribution and heat flux density vector diagram inside the switch cabinet, and extract the temperature rise value of the circuit breaker connection bar; Step S5: Determine whether the temperature rise exceeds a preset threshold. If it does, identify the heat flow bottleneck area based on the heat flux density vector diagram and adjust the structural parameters of the thermally conductive ceramic support. The structural parameters include the cross-sectional area, length, and arrangement position of the ceramic support heat-conducting plate. Step S6: Repeat steps S4 to S5 until the temperature rise value meets the preset requirements, and output the final optimized design scheme of the thermally conductive ceramic support.

[0014] In a possible implementation, in step S2, the ceramic material is selected from alumina ceramics, aluminum nitride ceramics or boron nitride ceramics, with a thermal conductivity of not less than 20 W / (m·K) and an insulation strength of not less than 10 kV / mm.

[0015] In a possible implementation, in step S3, the boundary condition further includes a high voltage of 40.5kV applied to the circuit breaker connection bar to simulate and verify that the surface electric field strength of the thermally conductive ceramic support is lower than the breakdown field strength of air under the rated operating voltage, so as to ensure its insulation safety.

[0016] The embodiments of this application have the following beneficial effects: This application provides a temperature field optimization structure and simulation design method for a 40.5kV medium-voltage environmentally friendly gas switchgear. By installing a highly thermally conductive and highly insulating alumina ceramic support between the circuit breaker connection bar and the lower gas box shell, an efficient heat conduction path is constructed, rapidly transferring heat from localized high-temperature areas to the cabinet shell for dissipation, significantly reducing the temperature rise of critical components. The multi-point layout design targets concentrated heat-generating areas for focused cooling, achieving a uniform temperature field. The installation method, using bolts and insulating gaskets, ensures both good thermal contact and high-voltage insulation. Fine surface treatment and the application of thermally conductive silicone grease further reduce contact thermal resistance, maximizing the thermal conductivity of the ceramic support. The accompanying simulation design method, through thermoelectric coupling multiphysics simulation and iterative optimization, provides a scientific support design scheme for switchgear of different specifications. The technical solution of this application effectively solves the heat dissipation bottleneck problem caused by the low thermal conductivity of gas in environmentally friendly gas switchgear. While meeting high-voltage insulation requirements, it significantly improves the current-carrying capacity and operational reliability of the equipment, which is of great significance for promoting SF6 replacement and the green development of power equipment. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and therefore should not be considered as a limitation on the scope of protection of this application. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 The overall structural diagram of the temperature field optimization structure of the 40.5kV medium-voltage environmentally friendly gas switchgear in this embodiment is shown. Figure 2 A schematic diagram of the ceramic support for the temperature field optimization structure of the 40.5kV medium-voltage environmentally friendly gas switchgear of this embodiment is shown. Figure 3 A schematic diagram of the ceramic support for the temperature field optimization structure of the 40.5kV medium-voltage environmentally friendly gas switchgear of this embodiment is shown. Figure 4 A schematic diagram of the ceramic support for the temperature field optimization structure of the 40.5kV medium-voltage environmentally friendly gas switchgear of this embodiment is shown.

[0019] Icons: 1. Lower air box; 2. Upper air box; 3. Circuit breaker connection bar; 4. Thermally conductive ceramic bracket; 41. Cold end of ceramic bracket; 42. Hot end of ceramic bracket; 43. Thermal plate of ceramic bracket; 44. Bolt hole; 45. Heat dissipation fins; 5. Busbar. Detailed Implementation

[0020] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0021] The components of the embodiments of this application described and illustrated in the accompanying drawings can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0022] In the following, the terms “comprising,” “having,” and their cognates, which may be used in various embodiments of this application, are intended only to indicate a particular feature, number, step, operation, element, component, or combination thereof, and should not be construed as excluding, firstly, the presence of one or more other features, numbers, steps, operations, elements, components, or combinations thereof, or adding the possibility of one or more features, numbers, steps, operations, elements, components, or combinations thereof.

[0023] Furthermore, the terms "first," "second," and "third" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0024] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of this application pertain. Terms (such as those defined in commonly used dictionaries) shall be interpreted as having the same meaning as in their contextual meaning in the relevant technical field and shall not be construed as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of this application.

[0025] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0026] Please refer to Figures 1 to 4This embodiment provides a temperature field optimization structure for a 40.5kV medium-voltage environmentally friendly gas switchgear, including a lower gas box 1, an upper gas box 2, a busbar 5 copper pipe, and at least one thermally conductive ceramic support 4. The lower gas box 1 is a sealed cavity structure, housing a circuit breaker and a circuit breaker connection bar 3 electrically connected to the circuit breaker. The upper gas box 2 is also a sealed cavity structure, fixedly stacked above the lower gas box 1, forming a sealed gas-filled cavity together with the lower gas box 1. This gas-filled cavity is filled with dry air or environmentally friendly gases such as nitrogen. A busbar 5 copper pipe is installed inside the upper gas box 2. The thermally conductive ceramic support 4 is fixedly installed in the internal cavity of the lower gas box 1. One end of each thermally conductive ceramic support 4 is thermally connected to the surface of the circuit breaker connection bar 3, and the opposite end is thermally connected to the inner wall of the lower gas box 1. With this structural arrangement, the thermally conductive ceramic bracket 4 forms a thermally conductive path between the circuit breaker connection bar 3 and the lower gas box 1 housing, which replaces the inefficient heat dissipation path that originally required gas convection and radiation with a highly efficient solid conduction path, thereby significantly improving the heat dissipation efficiency of key heat-generating parts.

[0027] In this embodiment, by setting a thermally conductive ceramic bracket 4 inside the switch cabinet and connecting its two ends to a heat source (circuit breaker connection bar 3) and a heat dissipation end (lower gas box 1 shell) respectively, the high thermal conductivity of the ceramic material is used to quickly conduct the heat from the local high temperature area to the cabinet shell, and then dissipate it to the external environment through the shell. Thus, without changing the insulation performance of the gas inside the gas box, the temperature rise of key parts such as the circuit breaker connection bar 3 is effectively reduced, the heat dissipation bottleneck problem caused by the low thermal conductivity of the environmentally friendly gas is solved, and the current carrying capacity and operational reliability of the equipment are improved.

[0028] In a preferred embodiment, the thermally conductive ceramic support 4 specifically includes a cold end 41, a heat-conducting plate 43, and a hot end 42. The cold end 41 is a flat plate structure, fitted and fixed to the inner wall of the lower air box 1 to ensure maximum contact area with the housing and good thermal conductivity. The hot end 42 is another flat plate structure, fitted and fixed to the surface of the circuit breaker connection bar 3 for efficient heat absorption from the heat-generating parts. The heat-conducting plate 43 is integrally connected between the cold end 41 and the hot end 42, forming a bridge for heat transfer, used to quickly conduct heat from the hot end 42 to the cold end 41. This integrated flat plate structure design ensures structural strength while minimizing contact thermal resistance along the heat conduction path.

[0029] In this embodiment, by dividing the thermally conductive ceramic support 4 into three functional parts—a cold end, a hot end, and a heat-conducting plate—and adopting an integrally molded structure, continuous heat conduction from the heat source to the heat dissipation end is achieved. The flat cold and hot ends can fit tightly against the mounting surface, increasing the heat exchange area, while the heat-conducting plate provides a low thermal resistance conduction channel, enabling heat to be efficiently and quickly dissipated, further optimizing the heat conduction effect.

[0030] In this embodiment, the shape and size of the ceramic support heat conduction plate 43 can be adapted to the specific location of the internal space of the lower air box 1 and the circuit breaker connection row 3. For example, it can be a straight plate structure, or an L-shaped or other irregular structure, as long as it can conduct the heat of the hot end 42 of the ceramic support to the cold end 41 of the ceramic support.

[0031] In a preferred embodiment, the ceramic support heat-conducting plate 43 has multiple bolt holes 44 on its surface. The heat-conducting ceramic support 4 is fastened to the inner wall of the circuit breaker connection bar 3 and the lower gas box 1 by bolts passing through the bolt holes 44. Insulating gaskets are provided between the bolts and the heat-conducting ceramic support 4, and / or between the bolts and the circuit breaker connection bar 3. The bolt fastening connection ensures that the heat-conducting ceramic support 4 maintains tight mechanical contact with the heat source and heat dissipation end, thereby reducing contact thermal resistance. The insulating gaskets prevent the high-voltage electric field from breaking down through the metal bolts, ensuring insulation safety in high-voltage environments.

[0032] In this embodiment, the use of bolts and insulating washers for fixing ensures both the robustness of the thermally conductive ceramic bracket 4 installation and its long-term operational reliability, while also solving the insulation problem of metal fasteners under high voltage conditions. This mechanical connection method allows the thermally conductive ceramic bracket 4 to maintain a tight fit with the contact surface during long-term operation, even under the influence of vibration or thermal expansion and contraction, thereby maintaining stable thermal conductivity.

[0033] In a preferred embodiment, multiple thermally conductive ceramic supports 4 are provided and distributed at intervals along the extension direction of the circuit breaker connection bar 3. At least one thermally conductive ceramic support 4 is positioned in the concentrated heat-generating area of ​​the circuit breaker connection bar 3, while the remaining thermally conductive ceramic supports 4 are positioned in other temperature-rising areas of the circuit breaker connection bar 3. This multi-point layout allows for differentiated heat dissipation at different locations on the circuit breaker connection bar 3, particularly focusing on cooling the areas with the highest temperatures, thereby achieving uniform optimization of the temperature field across the entire connection bar.

[0034] In this embodiment, by setting multiple thermally conductive ceramic supports 4 and distributing them at intervals along the circuit breaker connection bar 3, simultaneous heat dissipation at multiple points on a long conductor is achieved. Placing the most numerous supports in the area with the most concentrated heat generation can precisely solve the problem of local overheating, while the remaining supports are responsible for heat dissipation in the secondary high-temperature areas, making the temperature distribution of the entire circuit breaker connection bar 3 more uniform, avoiding local hot spots, and thus comprehensively improving the thermal management performance of the switchgear.

[0035] In a preferred embodiment, the thermally conductive ceramic support 4 is integrally sintered from alumina ceramic material. This alumina ceramic material has a thermal conductivity ≥25 W / (m·K), insulation strength ≥15 kV / mm, and bending strength ≥300 MPa25052709. Compared with other high thermal conductivity ceramics such as aluminum nitride and boron nitride, alumina ceramic has comprehensive advantages such as low cost, excellent insulation performance, high mechanical strength, and mature manufacturing process, making it particularly suitable for large-scale industrial applications in medium-voltage switchgear.

[0036] In this embodiment, by selecting alumina ceramic as the material for the heat-conducting support and setting specific parameters for thermal conductivity, insulation strength, and bending strength, it is ensured that the heat-conducting ceramic support 4 can withstand the mechanical stress and high-voltage environment inside the switchgear while meeting the requirements for efficient heat conduction. Compared with traditional insulating materials such as epoxy resin, alumina ceramic has significantly improved thermal conductivity and can truly act as a thermal bridge; compared with expensive materials such as aluminum nitride, it has better economic efficiency while ensuring heat dissipation.

[0037] In a preferred embodiment, the surface roughness Ra of the thermally conductive ceramic bracket 4 in contact with the circuit breaker connection bar 3 and the inner wall of the lower gas box 1 is ≤1.6μm, and thermally conductive silicone grease is applied between these contact surfaces to reduce contact thermal resistance. Fine surface processing increases the actual contact area, while the thermally conductive silicone grease fills the microscopic gaps; the combination of these two processes minimizes the thermal resistance at the contact interface, ensuring smooth heat conduction through the contact surface.

[0038] In this embodiment, by controlling the surface roughness and using a thermally conductive interface material, the contact thermal resistance problem caused by microscopic unevenness between solid contact surfaces is effectively solved. This treatment method allows the thermally conductive ceramic support 4 to fully utilize the high thermal conductivity of the material itself, avoiding heat accumulation at the interface, thereby achieving the theoretically designed optimal heat dissipation effect.

[0039] In a preferred embodiment, both the lower air box 1 and the upper air box 2 are rectangular cavity structures, and the length of the lower air box 1 is greater than the length of the upper air box 2. The lower air box 1 is provided with heat dissipation fins 45 on its outer wall, which can give the lower air box 1 a larger surface area for heat dissipation, while the heat dissipation fins 45 on the outer wall further increase the heat exchange area with the outside air and accelerate the dissipation of heat to the environment.

[0040] In this embodiment, by designing the lower air box 1 to be larger and adding heat dissipation fins 45, the heat conducted to the lower air box 1 shell can be dissipated to the surrounding environment more quickly, thereby maintaining the shell temperature at a lower level, ensuring the temperature difference between the two ends of the thermally conductive ceramic bracket 4, forming a continuous thermal driving force, and forming a complete and efficient heat dissipation chain of "heat source-thermally conductive bracket-shell-environment".

[0041] This application also provides a simulation design method applied to the temperature field optimization structure of the aforementioned 40.5kV medium-voltage environmentally friendly gas switchgear. The method includes the following steps: Step S1: Construct a three-dimensional geometric model of the thermally conductive ceramic support 4 and its related components. The related components include at least the circuit breaker connection bar 3 as a heat source, the lower air box 1 housing as the final heat dissipation end, and the bolts for connection. In this step, geometric models of the key components involved in the heat conduction process need to be built in 3D modeling software (such as SolidWorks, Pro / E, etc.). Specifically, at least the following parts need to be built: the circuit breaker connection bar 3, which is the main heat source; the lower air box 1, which is the final heat dissipation end; and the bolts used for connection. More importantly, a detailed model of the thermally conductive ceramic support 4 to be optimized needs to be built. This model should accurately reflect the structural shape, size, and bolt hole 44 positions of its cold end 41, heat-conducting plate 43, and hot end 42. When building the model, the geometric features of the actual components should be reproduced as accurately as possible. However, minor structures that do not affect the accuracy of the thermal analysis results (such as bolt threads, small chamfers, etc.) can be appropriately simplified to reduce the computational load of subsequent simulations. The completed model will be exported in a suitable format (such as STEP, IGES, etc.) for import into the finite element simulation software.

[0042] Step S2: Set the simulation material parameters. The material parameters should include at least the thermal conductivity, density, constant pressure heat capacity, dielectric strength of the ceramic material, and the equivalent contact thermal resistance at the bolt connection. In this step, the corresponding materials need to be defined or selected in the simulation software's material library, and key parameters need to be input. For the thermally conductive ceramic support 4, its material type (e.g., alumina ceramic, aluminum nitride ceramic, or boron nitride ceramic) needs to be set, and its thermal conductivity, density, constant-pressure heat capacity, and dielectric strength need to be input. These parameters directly determine the thermal conductivity and insulation performance of the ceramic support. For the circuit breaker connecting bar 3 (usually copper or aluminum) and the lower gas box 1 housing (usually stainless steel or aluminum alloy), the corresponding thermal conductivity, density, constant-pressure heat capacity, and equivalent contact thermal resistance at the bolted connection also need to be set. Since the two solid surfaces of the bolted connection are not in perfect contact, air exists in the microscopic gap, which will generate contact thermal resistance. This will affect the efficiency of heat transfer. Therefore, it is necessary to estimate or experimentally determine a reasonable equivalent contact thermal resistance value based on factors such as the material of the contact surface, surface roughness, and fastening force, and input it into the model to make the simulation results closer to the actual situation.

[0043] Step S3: Establish a thermal-fluid-solid multiphysics coupling simulation model in the finite element simulation software, import the three-dimensional geometric model, and set boundary conditions; the boundary conditions should include at least the Joule heat loss power of the circuit breaker connection bar 3, the pressure and convective heat transfer coefficient of the environmentally friendly gas inside the gas box, and the convective heat transfer coefficient between the gas box shell and the external environment. This step is performed in finite element simulation software (such as COMSOL Multiphysics, ANSYS, etc.). First, the 3D geometric model constructed in step S1 is imported into the software. Then, a multiphysics coupled model capable of simultaneously simulating solid heat conduction, gas convection, and thermal radiation needs to be established, i.e., a thermal-fluid-solid coupled model. Boundary conditions that accurately reflect the actual operating conditions of the switchgear are set, specifically including: Heat source boundary conditions: Set the Joule heat loss power of circuit breaker connection bar 3, which can be calculated based on the rated current of the switch cabinet (e.g., 2500A) and the resistance of the connection bar, and use it as the heat input of the model; Fluid boundary conditions: Set the type of environmentally friendly gas inside the gas tank (e.g., dry air), pressure (e.g., 0.13 MPa 2505 2709), and convective heat transfer coefficient between the gas and the solid wall. The convective heat transfer coefficient is affected by gas properties, flow velocity, and wall shape, and is a key parameter determining how much heat the gas carries away. Thermal boundary conditions: Set the convective heat transfer coefficient between the gas box shell and the external environment and the ambient temperature. The heat dissipation capacity of the shell depends on its surface area, surface condition (whether heat dissipation fins are installed 45) and the surrounding airflow.

[0044] Step S4: Run simulation calculations to obtain the temperature field distribution and heat flux density vector diagram inside the switch cabinet, and extract the temperature rise value of circuit breaker connection bar 3; In this step, after completing preprocessing (modeling, parameter assignment, boundary setting), the simulation solver is run for calculation. After the calculation is completed, the results need to be post-processed and analyzed. The main results obtained include: a temperature field distribution cloud map inside the switchgear, used to visually display the temperature levels of various parts, especially the temperature distribution on circuit breaker connection bar 3; and a heat flux density vector map, used to show the path and density of heat transfer, clearly revealing how heat flows from the heat source through the thermally conductive ceramic support 4 to the shell, and whether there is accumulation or bottleneck along the way. The temperature rise values ​​of key points (such as connection bars, outgoing line bars, etc.) of circuit breaker connection bar 3 need to be accurately extracted from the simulation results.

[0045] Step S5: Determine whether the temperature rise exceeds the preset threshold. If it does, identify the heat flow bottleneck area based on the heat flux density vector diagram and adjust the structural parameters of the thermally conductive ceramic support 4. The structural parameters include the cross-sectional area, length and arrangement position of the ceramic support heat-conducting plate 43. In this step, firstly, it is determined whether the temperature rise value of circuit breaker connection bar 3 extracted in step S4 exceeds a preset threshold. This threshold is usually based on the 75K limit specified in the national standard (GB), or a more stringent internal control standard set by the company. If the temperature rise value meets the requirements, the current design is feasible. If the temperature rise value exceeds the preset threshold, further analysis based on the heat flux density vector diagram is required to identify areas that hinder the smooth transfer of heat.

[0046] Step S6: Repeat steps S4 to S5 until the temperature rise value meets the preset requirements, and output the final optimized design scheme of the thermally conductive ceramic support 4.

[0047] In this embodiment, the simulation design method establishes a complete model including the thermally conductive ceramic support 4, the heat source, and the heat dissipation end, and sets boundary conditions that closely resemble actual operating conditions, thus accurately simulating the temperature field distribution inside the switchgear. Through multiple iterative optimizations, the optimal design of the thermally conductive ceramic support 4 can be obtained for specific cabinet structures and current parameters, avoiding the high costs of trial and error in physical prototypes and providing a basis for actual product development.

[0048] In a preferred embodiment, in step S2, the ceramic material is selected from alumina ceramics, aluminum nitride ceramics, or boron nitride ceramics, with a thermal conductivity of not less than 20 W / (m·K) and an insulation strength of not less than 10 kV / mm. By incorporating the parameters of multiple candidate materials into the simulation, the heat dissipation effects of different materials can be compared and analyzed, thereby providing data support for actual material selection. By setting the parameters of multiple candidate ceramic materials, the simulation method can quantitatively evaluate the improvement effect of different materials on temperature rise. Combined with cost factors, it helps designers make the optimal material selection, making the design scheme not only technically feasible but also economically reasonable.

[0049] In a preferred embodiment, step S3 further includes applying a 40.5kV high voltage to the circuit breaker connection bar 3 as a boundary condition. This is used to simulate and verify that, under rated operating voltage, the surface electric field strength of the thermally conductive ceramic support 4 is lower than the breakdown field strength of air, ensuring its insulation safety. By simultaneously considering the thermal and electric fields in the simulation, multiphysics optimization of thermoelectric coupling is achieved. This method ensures the insulation safety of the final designed thermally conductive ceramic support 4 while maintaining efficient heat conduction, avoiding the risk of local electric field distortion or insulation breakdown caused by the introduction of the thermally conductive support, truly achieving a balance between heat dissipation and insulation.

[0050] In summary, the temperature field optimization structure and simulation design method of the 40.5kV medium-voltage environmentally friendly gas switchgear provided in this application constructs an efficient heat conduction path by setting a high thermal conductivity and high insulation alumina ceramic support between the circuit breaker connection bar 3 and the lower gas box 1 shell. This rapidly conducts heat from local high-temperature areas to the cabinet shell for dissipation, significantly reducing the temperature rise of critical components. The multi-point layout design targets concentrated heat-generating areas for focused cooling, achieving temperature field uniformity. The installation method using bolt fastening combined with insulating gaskets ensures both good thermal contact and high-voltage insulation. Fine surface treatment and the application of thermally conductive silicone grease further reduce contact thermal resistance, maximizing the thermal conductivity of the ceramic support. The accompanying simulation design method, through thermoelectric coupling multiphysics simulation and iterative optimization, provides a scientific support design scheme for switchgear of different specifications. The technical solution of this application effectively solves the heat dissipation bottleneck problem caused by the low thermal conductivity of gas in environmentally friendly gas switchgear. While meeting high-voltage insulation requirements, it significantly improves the current carrying capacity and operational reliability of the equipment, which is of great significance for promoting SF6 replacement and the green development of power equipment.

[0051] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A temperature field optimization structure for a 40.5kV medium-voltage environmentally friendly gas switchgear, characterized in that, include: The lower air box contains a circuit breaker and a circuit breaker connection bar electrically connected to the circuit breaker. The upper air box is fixedly installed above the lower air box and together with the lower air box forms a sealed inflation cavity. A busbar is installed inside the upper air box. At least one thermally conductive ceramic bracket is fixedly installed inside the lower air box. One end of each thermally conductive ceramic bracket is connected to the surface of the circuit breaker connection bar, and the other end is connected to the inner wall surface of the lower air box, so as to form a thermally conductive passage between the circuit breaker connection bar and the shell of the lower air box.

2. The temperature field optimization structure for the 40.5kV medium-voltage environmentally friendly gas switchgear according to claim 1, characterized in that, The thermally conductive ceramic support includes: The cold end of the ceramic support has a flat plate structure and is fixedly attached to the inner wall of the lower air box; The hot end of the ceramic bracket has a flat plate structure and is fixedly attached to the surface of the circuit breaker connection bar. A ceramic support heat-conducting plate is integrally connected between the cold end and the hot end of the ceramic support, and is used to conduct heat from the hot end to the cold end of the ceramic support.

3. The temperature field optimization structure for the 40.5kV medium-voltage environmentally friendly gas switchgear according to claim 2, characterized in that, The surface of the ceramic support heat-conducting plate is provided with multiple bolt holes; the heat-conducting ceramic support is fastened to the inner wall of the circuit breaker connection bar and the lower air box by bolts passing through the bolt holes, and an insulating gasket is provided between the bolt and the heat-conducting ceramic support, and / or between the bolt and the circuit breaker connection bar.

4. The temperature field optimization structure for the 40.5kV medium-voltage environmentally friendly gas switchgear according to claim 2, characterized in that, The number of thermally conductive ceramic supports is multiple, and they are distributed at intervals along the extension direction of the circuit breaker connection bar; wherein, at least one thermally conductive ceramic support is correspondingly arranged in the heat-concentrating area of ​​the circuit breaker connection bar, and the remaining thermally conductive ceramic supports are arranged in other temperature-rising areas of the circuit breaker connection bar.

5. The temperature field optimization structure for the 40.5kV medium-voltage environmentally friendly gas switchgear according to claim 1, characterized in that, The thermally conductive ceramic support is integrally sintered from alumina ceramic material. The thermal conductivity of the alumina ceramic material is ≥25W / (m·K), the insulation strength is ≥15 kV / mm, and the bending strength is ≥300 MPa25052709.

6. The temperature field optimization structure for the 40.5kV medium-voltage environmentally friendly gas switchgear according to claim 5, characterized in that, The surface roughness Ra of the thermally conductive ceramic bracket that contacts the circuit breaker connection bar and the inner wall of the lower air box is ≤1.6μm, and thermally conductive silicone grease is applied between the contact surfaces.

7. The temperature field optimization structure for the 40.5kV medium-voltage environmentally friendly gas switchgear according to claim 1, characterized in that, Both the lower and upper air boxes are rectangular cavity structures, and the length of the lower air box is greater than the length of the upper air box. Heat dissipation fins are provided on the outer wall of the lower air box.

8. A simulation design method applied to the temperature field optimization structure of a 40.5kV medium-voltage environmentally friendly gas switchgear as described in any one of claims 1 to 7, characterized in that, Includes the following steps: Step S1: Construct a three-dimensional geometric model of the thermally conductive ceramic support and its related components. The related components include at least the circuit breaker connection bar as a heat source, the lower air box shell as the final heat dissipation end, and the bolts for connection. Step S2: Set the simulation material parameters, which include at least the thermal conductivity, density, constant pressure heat capacity, dielectric strength of the ceramic material, and the equivalent contact thermal resistance at the bolt connection. Step S3: Establish a physical field coupling simulation model in the finite element simulation software, import the three-dimensional geometric model, and set boundary conditions; the boundary conditions include at least the Joule heat loss power of the circuit breaker connection bar, the pressure and convective heat transfer coefficient of the environmentally friendly gas inside the gas box, and the convective heat transfer coefficient between the gas box shell and the external environment. Step S4: Run simulation calculations to obtain the temperature field distribution and heat flux density vector diagram inside the switch cabinet, and extract the temperature rise value of the circuit breaker connection bar; Step S5: Determine whether the temperature rise exceeds a preset threshold. If it does, identify the heat flow bottleneck area based on the heat flux density vector diagram and adjust the structural parameters of the thermally conductive ceramic support. The structural parameters include the cross-sectional area, length, and arrangement position of the ceramic support heat-conducting plate. Step S6: Repeat steps S4 to S5 until the temperature rise value meets the preset requirements, and output the final optimized design scheme of the thermally conductive ceramic support.

9. The simulation design method according to claim 8, characterized in that, In step S2, the ceramic material is selected from alumina ceramic, aluminum nitride ceramic or boron nitride ceramic, and its thermal conductivity is not less than 20 W / (m·K) and its insulation strength is not less than 10 kV / mm.

10. The simulation design method according to claim 8, characterized in that, In step S3, the boundary conditions also include a 40.5kV high voltage applied to the circuit breaker connection bar to simulate and verify that the surface electric field strength of the thermally conductive ceramic support is lower than the breakdown field strength of air under the rated operating voltage, so as to ensure its insulation safety.

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