Extra-high voltage dry terminal structure and design method thereof

Abstract

This invention relates to the field of ultra-high voltage (UHV) power transmission equipment technology, specifically to an UHV dry-type terminal structure and its design method. The structure includes a conductor connection area, a composite sleeve area, a tailpipe stress relief area, and a lattice coordination area. The conductor connection area includes an upper component and a conductor connecting rod. The composite sleeve area includes a composite sleeve assembly. The tailpipe stress relief area includes a tailpipe and supporting insulators arranged around the tailpipe. The upper component, composite sleeve assembly, and tailpipe are connected sequentially from top to bottom. The conductor connecting rod passes through the upper component, composite sleeve assembly, and tailpipe sequentially along the axial direction. The lattice coordination area includes a lattice component for enhanced heat dissipation, which is fitted around the bottom periphery of the composite sleeve assembly and / or the tailpipe. This invention enhances heat dissipation by adding a lattice component to the bottom of the composite sleeve assembly and / or the tailpipe. This not only makes the heat dissipation path more efficient and greatly increases the heat dissipation area, thereby improving heat dissipation efficiency and allowing heat to dissipate rapidly, but also effectively eliminates the problem of uneven electric field caused by differences in shell curvature, reducing the risk of electro-erosion and surface discharge, and ensuring electrical safety during long-term equipment operation.

Description

Technical Field

[0001] This invention relates to the field of ultra-high voltage power transmission equipment technology, specifically to an ultra-high voltage dry-type terminal structure and its design method. Background Technology

[0002] In ultra-high voltage (UHV) power transmission systems, dry-type terminal structures serve as crucial components for conductor connection, insulation transition, and uniform external field, and their performance directly impacts the safe and stable operation of transmission equipment. Existing dry-type terminal structures still exhibit significant shortcomings in terms of thermo-mechanical-electric multi-physics coupling performance, lightweight design, and manufacturing consistency, specifically in the following aspects:

[0003] (1) The existing dry terminal metal shell structure has a single heat conduction direction and limited heat dissipation area. It cannot effectively dissipate heat under high heat flux density conditions, resulting in excessive temperature rise of the shell. Differences in the curvature and conductivity of the outer surface cause electric field distortion, which can easily lead to electro-erosion and surface discharge risks, resulting in electrical safety problems during long-term operation of the equipment.

[0004] (2) Existing dry-type terminal conductor connection parts usually adopt a homogeneous metal integral structure with fixed conductive and heat conduction paths, making it difficult to achieve coordinated control of current distribution and temperature field. Under long-term high current density operation conditions, local areas are prone to heat accumulation and hot spot effects, resulting in increased contact resistance, excessive temperature rise and metal fatigue damage, affecting the long-term stability of terminal conductor connection.

[0005] (3) Existing dry terminals usually use mechanical connection or adhesive sealing to combine metal conductors with composite insulation structures. Due to the large difference in thermal expansion coefficients between metal and composite materials, stress concentration and microcrack propagation are easily generated under thermal cycling and electric field, which in turn induces local delamination, insulation performance deterioration and structural sealing failure, resulting in unstable connection and directly affecting the reliability and long-term service performance of the terminal structure.

[0006] (4) In order to ensure strength and rigidity, existing dry terminals generally adopt a high-density metal integral structure, which results in a large mass and inconvenience in installation and maintenance. At the same time, the material properties are uniform and the functions of each area cannot be optimized by partition, making it difficult to achieve a coordinated design of high conductivity in the conductor connection area, flexible transition in the composite tube sleeve area, and high heat dissipation. Summary of the Invention

[0007] The purpose of this invention is to provide an ultra-high voltage dry-type terminal structure and its design method, which can at least solve some of the defects in the prior art.

[0008] To achieve the above objectives, the technical solution of the present invention is an ultra-high voltage dry-type terminal structure, including a conductor connection area, a composite sleeve area, a tailpipe stress relief area, and a lattice cooperation area. The conductor connection area includes an upper component and a conductor connecting rod. The composite sleeve area includes a composite sleeve assembly. The tailpipe stress relief area includes a tailpipe and a supporting insulator arranged around the tailpipe. The upper component, the composite sleeve assembly, and the tailpipe are connected sequentially from top to bottom. The conductor connecting rod passes through the upper component, the composite sleeve assembly, and the tailpipe sequentially along the axial direction. The lattice cooperation area includes a lattice assembly for enhancing heat dissipation. The lattice assembly is sleeved around the bottom of the composite sleeve assembly and / or around the tailpipe.

[0009] As one embodiment, the composite sleeve assembly includes a composite sleeve and a stress cone module disposed within the composite sleeve. The top and bottom of the composite sleeve are sealed by the upper end assembly and the stress cone module, respectively. The cavity of the composite sleeve is filled with silicone oil. The tail tube is connected to the stress cone module, and the lattice assembly is sleeved around the tail tube and / or the bottom of the composite sleeve.

[0010] As one embodiment, the upper component and the conductor connecting rod are both made of a high conductivity metal material; the tail tube and the stress cone module are made of a composite gradient metal material, and from top to bottom, the conductivity of the tail tube and the stress cone module decreases while the thermal conductivity increases; the lattice component is made of a high thermal conductivity metal material.

[0011] As one implementation method, the stress cone module adopts a copper-based composite gradient metal, with a copper alloy in the upper part and a copper-aluminum-magnesium alloy in the middle and lower parts. From top to bottom, the proportion of copper in the copper-aluminum-magnesium alloy gradually decreases, while the proportions of aluminum and magnesium gradually increase.

[0012] As one embodiment, the tailpipe is made of a copper alloy and an aluminum-magnesium alloy composite gradient metal, with the upper part made of copper alloy and the middle and lower parts made of aluminum-magnesium alloy, and the proportion of aluminum and magnesium in the aluminum-magnesium alloy gradually increases from top to bottom.

[0013] As one implementation method, any one of the structures in the lattice component, the stress cone module, and the tail tube is printed using a laser powder bed melting process.

[0014] As one implementation method, during the printing process of the lattice component, the porosity and rod diameter are programmably varied by dynamically adjusting the energy density, scanning spacing and layer thickness parameters; during the printing process of the stress cone module and the tail tube, the material gradient is achieved by dynamically adjusting the material composition and layer thickness parameters.

[0015] As one embodiment, the lattice assembly includes a composite tube sleeve region lattice assembly sleeved around the bottom periphery of the composite tube sleeve assembly and a tail tube stress relief region lattice assembly sleeved around the tail tube. Both the composite tube sleeve region lattice assembly and the tail tube stress relief region lattice assembly are formed by lattice units arranged along the axial and circumferential directions.

[0016] As one embodiment, the porosity of the lattice units in the lattice assembly gradually increases from top to bottom.

[0017] The present invention also provides a design method for the ultra-high voltage dry-type terminal structure described in any one of the above claims, characterized in that it includes the following steps:

[0018] S1. Based on the operating characteristics of UHV dry-type terminals under high voltage, high load and high heat flux density conditions, the structure is functionally partitioned and configured, and divided into conductor connection area, composite sleeve area, tail tube stress relief area and lattice cooperation area.

[0019] S2. Design the structure and materials of the lattice coordinating region to optimize thermal conductivity and mechanical properties;

[0020] S3. Design the structure and materials of the composite sleeve area and the tailpipe stress relief area to optimize structural stability;

[0021] S4. Establish a thermo-mechanical-electric multi-field coupling model for the terminal structure, and optimize the current conduction, heat flow conduction and mechanical stress field of the conductor connection area, composite sleeve area, tail tube stress relief area and lattice cooperation area to balance the thermo-mechanical-electric coupling effect.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention enhances heat dissipation by adding lattice components to the bottom and / or tail pipe of the composite tube assembly. This not only makes the heat dissipation path more efficient and the heat dissipation area greatly increased, thereby improving the heat dissipation efficiency and enabling the heat to spread quickly, but also effectively eliminates the problem of uneven electric field caused by the difference in the curvature of the shell, reduces the risk of electro-erosion and surface discharge, and ensures the electrical safety of the equipment during long-term operation. In addition, the lattice components adopt a lightweight lattice structure, which can reduce the volume of ineffective materials, effectively reduce the structural mass, and facilitate the realization of lightweight.

[0024] (2) The present invention uses a high conductivity metal material in the conductor connection area to ensure the high efficiency of current conduction; uses a high thermal conductivity metal material in the lattice coordination area to enhance heat dissipation performance; and uses a composite gradient metal material in the composite sleeve area and the tail tube stress relief area to achieve synergistic optimization of the conductive area and the thermally conductive area, improve the thermal-electric synergistic effect, and form a smooth transition from high conductivity to low stiffness by designing continuous changes in metal composition and performance, effectively avoiding stress concentration and temperature rise concentration problems caused by thermal expansion differences, significantly improving heat dissipation efficiency and structural stability, and extending the service life of the equipment.

[0025] (3) The lattice components, stress cone modules, and tail tubes of the present invention are manufactured by additive manufacturing using laser powder bed melting technology. By precisely controlling the composition and distribution of the materials, the geometric accuracy, metallurgical bonding quality, and consistency of the structure are guaranteed, making the manufacturing process of the dry terminal structure more efficient and precise.

[0026] (4) The present invention integrates a high thermal conductivity lattice synergy region and a composite gradient metal shell in the composite sleeve region and the tail tube stress relief region, thereby improving the thermal diffusion efficiency and external field uniformity, significantly suppressing surface electro-erosion and discharge phenomena, and thus ensuring electrical safety margin. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the ultra-high voltage dry terminal structure provided in an embodiment of the present invention;

[0029] Figure 2 This is a cross-sectional schematic diagram of an ultra-high voltage dry terminal structure provided in an embodiment of the present invention;

[0030] Figure 3 This is an exploded view of the ultra-high voltage dry terminal structure provided in an embodiment of the present invention;

[0031] Figure 4 A schematic diagram of the lattice assembly of the ultra-high voltage dry terminal structure provided in an embodiment of the present invention;

[0032] In the diagram: 1. Conductor connecting rod; 2. Upper assembly; 21. Shielding cover; 22. Pressure cap; 23. Tight cap; 3. Composite sleeve assembly; 31. Composite sleeve; 32. Silicone oil; 33. Stress cone cover; 34. Stress cone; 35. Stress cone support; 4. Lattice assembly; 41. Lattice assembly of composite sleeve area; 42. Lattice assembly of tail tube stress relief area; 5. Support insulator; 6. Tail tube; 7. Bolt and nut connector. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0034] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0036] like Figures 1-3As shown, this embodiment provides an ultra-high voltage dry-type terminal structure, including a conductor connection area, a composite sleeve area, a tailpipe stress relief area, and a lattice cooperation area. The conductor connection area includes an upper component 2 and a conductor connecting rod 1. The composite sleeve area includes a composite sleeve assembly 3. The tailpipe stress relief area includes a tailpipe 6 and a supporting insulator 5 arranged around the tailpipe 6. The upper component 2, the composite sleeve assembly 3, and the tailpipe 6 are connected sequentially from top to bottom. The conductor connecting rod 1 passes through the upper component 2, the composite sleeve assembly 3, and the tailpipe 6 sequentially along the axial direction. The lattice cooperation area includes a lattice assembly 4 for enhancing heat dissipation. The lattice assembly 4 is sleeved around the bottom of the composite sleeve assembly 3 and / or around the tailpipe 6. This embodiment enhances heat dissipation by adding a lattice component 4 to the bottom of the composite sleeve assembly 3 and / or the tail pipe 6. This not only makes the heat dissipation path more efficient and greatly increases the heat dissipation area, thereby improving heat dissipation efficiency and enabling rapid heat dissipation, but also effectively eliminates the problem of uneven electric field caused by the difference in the curvature of the outer shell, reduces the risk of electro-erosion and surface discharge, and ensures the electrical safety of the equipment during long-term operation. Furthermore, the lattice component 4 adopts a lightweight lattice structure, which can reduce the volume of ineffective materials and is conducive to structural lightweighting.

[0037] In this embodiment, the conductor connection area includes an upper component 2 and a conductor connecting rod 1. The upper component 2 is located at the top of the structure, and the conductor connecting rod 1 is used to realize the current input and output and mechanical load transmission of the main body. The upper component 2 is used to form a uniform electric field distribution and provide stable limiting and sealing in the axial direction. The composite sleeve area is located in the middle of the structure and is a key area for controlling the electric field distribution and insulation performance. It is mainly used to achieve electric field homogenization between the metal conductor and the composite insulation system. The lattice coordination area is located in the middle and lower part of the structure. It achieves thermal conductivity enhancement and mass reduction through topology optimization of the lattice structure and plays a buffering and heat dissipation role in the thermal cycling environment. The tail tube stress relief area is located at the bottom of the structure and undertakes the dispersion and release of thermal and mechanical stress. The supporting insulator 5 plays a structural support and positioning role, so that the overall structure remains stable under the multi-physical field coupling environment of heat, force and electricity. Each functional area is arranged along the axial direction to form a continuous path of current conduction, heat diffusion and mechanical support, realizing synergistic optimization under the conditions of thermal-mechanical-electric multi-field coupling. The overall structure adopts an axisymmetric cylindrical layout to ensure the continuity and uniformity of current, heat flow and force flow paths, achieving the unified goal of lightweight, high thermal conductivity and high reliability.

[0038] In some embodiments, the composite sleeve assembly 3 includes a composite sleeve 31 and a stress cone 34 module disposed within the composite sleeve. The top and bottom of the composite sleeve 31 are sealed by the upper end assembly 2 and the stress cone 34 module, respectively. The cavity of the composite sleeve 31 is filled with silicone oil 32. The tail tube 6 is connected to the stress cone 34 module, and the lattice assembly 4 is sleeved around the tail tube 6 and / or the bottom of the composite sleeve 31. The two ends of the composite sleeve 31 are sealed by the upper end assembly 2 and the stress cone 34 module, and the cavity formed is filled with silicone oil 32 to achieve electric field equalization. The lattice assembly 4 is sleeved around the bottom of the composite sleeve 31 to provide a continuous channel for load and heat flow transfer.

[0039] like Figures 1-3 As shown, the stress cone 34 module includes a stress cone 34, a stress cone cover 33, and a stress cone support 35. The stress cone 34 is disposed on the stress cone support 35, and the stress cone cover 33 covers the stress cone 34 and the stress cone support 35. The stress cone cover 33 is disposed at the bottom of the cavity of the composite sleeve 31. The top of the tail tube 6 is connected to the bottom of the stress cone support 35. Furthermore, the stress cone 34, the stress cone cover 33, and the stress cone support 35 are arranged in a multi-layer coaxial manner, with the cone angle controlled within the range of 25° to 30°, forming a smooth electric field transition zone. The coaxial layered layout achieves synergistic optimization of thermal, mechanical, and electric fields, making the stress distribution more uniform and significantly reducing stress concentration and local temperature rise. The tail tube 6 and the stress cone support 35 are connected by mechanical fit and an insulating sealing layer to achieve a smooth electric field transition and stress relief. The lattice component 4 and the composite sleeve component 3 adopt a metal nesting and chemical bonding composite connection process to ensure metallurgical bonding and structural continuity.

[0040] Furthermore, the composite sleeve 31 is made of epoxy glass fiber reinforced composite material, manufactured through vacuum infusion and molding processes, with silicone oil 32 injected into the inner cavity to form a uniform electric field and a heat convection channel. The wall thickness of the composite sleeve 31 is approximately 8 mm, and the stress cone 34 module is embedded within it. To prevent discharge and stress concentration, the composite sleeve 31 and the conductor connecting rod 1 adopt a composite structure of a shielding ring and a metal plating layer, achieving a smooth transition of the electric field gradient and improving sealing reliability. The curing process of the composite sleeve 31 adopts a graded heating and low-stress curing mode to ensure dimensional stability and dielectric strength. Verification conditions include testing the electric field distribution and stress in the connection area between the composite sleeve 31 and the conductor to ensure sealing performance and electrical safety.

[0041] like Figure 2 and Figure 3As shown, a fixing plate is provided at the bottom of the composite sleeve 31, and the upper end of the supporting insulator 5 is connected to the fixing plate. In one embodiment, four supporting insulators 5 are arranged at intervals around the tail pipe 6, and the tops of the four supporting insulators 5 are all connected to the fixing plate.

[0042] Furthermore, both the upper component 2 and the conductor connecting rod 1 are made of high-conductivity metal materials; the tail tube 6 and the stress cone 34 module are made of composite gradient metal materials, and from top to bottom, the conductivity of the tail tube 6 and the stress cone 34 module decreases while the thermal conductivity increases; the lattice component 4 is made of high-thermal-conductivity metal materials. In this embodiment, high-conductivity metal materials are used in the conductor connection area to maintain high conductivity and high rigidity to ensure current carrying capacity and mechanical stability, ensuring efficient current conduction; high-thermal-conductivity metal materials are used in the lattice coordination area to quickly transfer the generated Joule heat, enhancing heat dissipation performance and eliminating local hot spots; composite gradient metal materials are used in the composite sleeve area and the tail tube stress relief area to achieve a smooth transition between conductivity and thermal conductivity. By partitioning the materials of each functional area, the terminal equipment can operate stably under high current, high temperature, and high load conditions.

[0043] Preferably, the stress cone 34 module uses a copper-based composite gradient metal, with a copper alloy in the upper part and a copper-aluminum-magnesium alloy in the middle and lower parts. From top to bottom, the proportion of copper in the copper-aluminum-magnesium alloy gradually decreases, while the proportions of aluminum and magnesium gradually increase. The stress cone 34 module undergoes a gradual material transition in the axial direction to optimize its electrical and thermal conductivity. Specifically, as shown... Figure 2 and Figure 3 As shown, the upper frustum portion of stress cone 34 and stress cone cover 33 is made of a high-conductivity copper alloy to improve conductivity and reduce the coefficient of thermal expansion. The lower annular portion of stress cone 34 and stress cone cover 33, and stress cone support 35, are made of copper-aluminum-magnesium alloy, gradually transitioning from copper alloy to copper-aluminum-magnesium alloy containing aluminum and magnesium to increase material strength and corrosion resistance, while ensuring good mechanical and thermal properties. In the composite sleeve area, the metal volume fraction of stress cone 34 module gradually decreases from top to bottom, and the elastic modulus of the material is controlled within the range of 30 GPa to 70 GPa, transitioning from a high-stiffness copper alloy to a copper-aluminum-magnesium alloy with higher thermal conductivity. The specific density distribution is between 0.6-1.0 g / cm³, achieving a smooth transition between electrical and thermal conductivity, effectively mitigating the risk of thermal stress concentration and delamination, thereby improving the service reliability of the terminal structure.

[0044] Preferably, the tailpipe 6 is a composite gradient metal made of copper alloy and aluminum-magnesium alloy, with the upper part made of copper alloy and the middle and lower parts made of aluminum-magnesium alloy, and the proportion of aluminum and magnesium in the aluminum-magnesium alloy gradually increasing from top to bottom. The tailpipe 6 undergoes a gradual change in material in the axial direction to achieve a balance between high conductivity and high strength. Specifically, as shown... Figure 2 and Figure 3 As shown, the upper part of the tailpipe 6 extending into the stress cone support 35 is made of copper alloy to ensure high electrical conductivity and thermal stability in this area; the middle and lower parts of the tailpipe 6 are made of aluminum-magnesium alloy to optimize heat dissipation, and its mechanical strength and resistance to electrolytic corrosion are improved by gradually increasing the proportion of aluminum and magnesium. In the stress relief zone of the tailpipe, the density of the metal gradually increases, while its geometry is changed to enhance heat dissipation efficiency and energy dissipation capacity.

[0045] This embodiment integrates a high thermal conductivity lattice synergistic region and a composite gradient metal shell in the composite sleeve region and the tailpipe stress relief region, thereby improving heat diffusion efficiency and external field uniformity, significantly suppressing surface electrolytic corrosion and discharge phenomena, and ensuring electrical safety margin. This embodiment effectively overcomes the problems of insufficient heat dissipation capacity and uneven electric field distribution in traditional structures, and improves the system's heat dissipation capacity by optimizing the heat dissipation path and enhancing the thermal conductivity of the material.

[0046] The stress cone 34 module and the tailpipe 6, through the gradual transition of this composite gradient metal material, not only improve electrical and thermal conductivity but also maintain structural stability, high-temperature resistance, and corrosion resistance under different load conditions. The composite gradient metal module, consisting of the stress cone 34 module and the tailpipe 6, runs through the composite sleeve area and the tailpipe stress relief area, enabling continuous transition and synergistic control of multi-physics field performance. By constructing a gradient parameter field along the axial direction, it spatially adjusts the metal volume fraction, structural density distribution, and cross-sectional geometry, forming a continuous performance mapping from high conductivity and high strength to high thermal conductivity and low stiffness. The surfaces of the stress cone 34 module and the tailpipe 6 are treated with a composite coating of electroless nickel plating and micro-arc oxidation to improve their resistance to electrolytic corrosion and environmental durability.

[0047] Preferably, the upper component 2 and the conductor connecting rod 1 are made of copper alloy with high conductivity, which has excellent electrical conductivity and thermal stability; the lattice component 4 is made of Al-Mg-Sc-Zr high-strength lightweight aluminum alloy with high thermal conductivity and low stiffness, which has excellent thermal conductivity, good forming fluidity and low crack sensitivity, and is suitable for manufacturing cell-scale lattice structures.

[0048] In some embodiments, any one of the structures—the lattice component 4, the stress cone 34 module, and the tail tube 6—is formed using laser powder bed melting (LBD). This embodiment utilizes LBD additive manufacturing, ensuring the metallurgical bonding quality and consistency of the structure through precise control of material composition and distribution. The manufacturing process includes: 3D CAD modeling and multiphysics simulation, powder placement and parameter optimization, LBD additive manufacturing, hot isostatic pressing and stress-relief annealing, composite insulation curing, precision machining and surface coating preparation, assembly, and inspection. During assembly, the coaxiality of the conductor connecting rod 1, upper component 2, composite sleeve component 3, and tail tube 6 is controlled within 0.05 mm to ensure high-precision structural connections. A gap exists between the conductor connecting rod 1 and the upper component 2, composite sleeve component 3, and tail tube 6, controlled between 0.5 and 1.2 mm, further optimizing current density and heat flow path, and reducing resistance.

[0049] Furthermore, during the printing process of the lattice component 4, programmable variations in porosity and rod diameter are achieved by dynamically controlling energy density, scanning spacing, and layer thickness parameters. During the printing processes of the stress cone 34 module and the tail tube 6, gradient changes in material composition are achieved by dynamically adjusting material composition and layer thickness parameters. In the printing process of the lattice component 4, programmable variations in porosity and rod diameter are achieved by dynamically controlling energy density, scanning spacing, and layer thickness parameters, ensuring optimal configuration of the structure in terms of load-bearing and thermal conductivity. Structural adjustment is achieved by adjusting the size of the lattice units, allowing the size of the lattice units in the lattice component 4 to gradually change along the axial direction, ensuring optimized coupling of conductive, thermal, and mechanical paths. During the printing processes of the stress cone 34 module and the tail tube 6, gradient changes in material composition are achieved by dynamically adjusting material composition and layer thickness parameters, eliminating abrupt changes in thermal stress at heterogeneous interfaces. After molding, residual stress is eliminated by hot isostatic pressing, and anodizing is performed to obtain high corrosion resistance. Preferably, the tail tube stress relief zone lattice component 42, which is sleeved around the tail tube 6, and the tail tube 6 can be manufactured as an integrated unit in the same printing process. This not only saves processes and improves manufacturing efficiency, but also solves the problem that traditional processes cannot process complex structures.

[0050] In some embodiments, the lattice assembly 4 includes a composite tube sleeve region lattice assembly 41 sleeved around the bottom periphery of the composite tube sleeve assembly 3 and a tail tube stress relief region lattice assembly 42 sleeved around the tail tube 6. Both the composite tube sleeve region lattice assembly 41 and the tail tube stress relief region lattice assembly 42 are formed by lattice units arranged axially and circumferentially. By employing a lightweight lattice framework structure, the volume of ineffective material is reduced. The lattice units in the composite tube sleeve region lattice assembly 41 and the tail tube stress relief region lattice assembly 42 are uniformly distributed in both the radial and axial directions, forming a ring-shaped multi-scale support and heat-conducting network, which achieves the combined functions of structural weight reduction, enhanced heat dissipation, and stress homogenization. In one embodiment, two composite tube sleeve region lattice assemblies 41 are axially spaced around the bottom periphery of the composite tube sleeve assembly 3, and two tail tube stress relief region lattice assemblies 42 are axially spaced around the periphery of the tail tube 6. Both the composite tube sleeve region lattice component 41 and the tail tube stress relief region lattice component 42 can be formed by laser powder bed melting process.

[0051] Preferably, the porosity of the lattice units in the lattice component 4 gradually increases from top to bottom, such as... Figure 4 As shown. Furthermore, the volume fraction of the lattice units varies in the range of 30% to 50%. The porosity of the lattice units gradually increases along the axial direction from the bottom of the composite sleeve 31 to the tail tube 6 to improve thermal conductivity, thereby achieving a continuous gradient from a high-stiffness layer to a high-thermal-conductivity layer in the axial direction.

[0052] In this embodiment, the nodes of each lattice unit employ rounded corners to reduce stress concentration and ensure smooth heat and force flow. The size variation and node density of the lattice units gradually transition from a high-stiffness layer to a high-thermal-conductivity layer. This is achieved by adjusting the tilt angle and cell size of the lattice bars, allowing heat to diffuse rapidly radially and release gradually axially. This structure ensures uniform heat and force flow, effectively dispersing and mitigating thermal stress. The lattice unit size gradually varies axially, ensuring optimized coupling of conductive, heat flow, and mechanical paths. The lattice units employ a three-dimensional topology-optimized configuration, enabling rapid radial diffusion and gradual axial release of heat, thereby effectively reducing temperature gradient peaks and improving thermal diffusion efficiency. The lattice design also effectively homogenizes stress distribution, reduces local stress concentration, and enhances the overall strength and fatigue resistance of the structure.

[0053] In this embodiment, the distribution of the moment of inertia of the tailpipe 6 can be adjusted by changing its geometry to ensure uniform stress distribution. The internal heat dissipation structure of the tailpipe 6 adopts a multi-stage heat dissipation path and is combined with magnesium alloy material to enhance the heat dissipation effect. The stress relief design reduces stress concentration through a hierarchical structure, improving the reliability of the terminal during high-voltage long-cycle operation.

[0054] In some embodiments, the upper component 2 includes a shield 21, a pressure cap 22, and a tight cap 23. The tight cap 23 is disposed at the bottom of the shield 21, and the pressure cap 22 is disposed inside the shield 21. The composite sleeve 31 is fixedly connected to the pressure cap 22 and the tight cap 23. The pressure cap 22 and the tight cap 23 provide stable limiting and sealing in the axial direction. The shield 21 forms a uniform electric field distribution to suppress local electric field concentration and corona discharge at the high-voltage end. The external pressure cap 22 and the tight cap 23 provide stable limiting and sealing in the axial direction. The upper component 2 is arranged coaxially. The conductor connecting rod 1 passes through the shield 21, the pressure cap 22, and the tight cap 23 along the axis to ensure continuous current path and consistent force transmission.

[0055] This embodiment constructs a multi-layered composite metal system by introducing a shell of composite gradient metal material and a high thermal conductivity lattice component 4 into the composite sleeve region and tailpipe stress relief region of the terminal structure. This achieves global coordination and local strengthening of electrical conductivity, thermal conductivity, and mechanical properties, thereby significantly reducing temperature rise and stress concentration. Simultaneously, the use of gradient metal materials avoids the instability caused by traditional dissimilar materials, enhancing the overall integrity and durability of the structure. By optimizing the synergistic effect of heat flow and current paths, electrical connection and heat dissipation functions are more balanced, improving the operational stability of the terminal under high current and high temperature environments.

[0056] This embodiment also provides a design method for the ultra-high voltage dry-type terminal structure described in any one of the above claims, characterized by comprising the following steps:

[0057] S1. Based on the operating characteristics of UHV dry-type terminals under high voltage, high load and high heat flux density conditions, the structure is functionally partitioned and configured, and divided into conductor connection area, composite sleeve area, tail tube stress relief area and lattice cooperation area.

[0058] S2. Design the structure and materials of the lattice coordinating region to optimize thermal conductivity and mechanical properties;

[0059] S3. Design the structure and materials of the composite sleeve area and the tailpipe stress relief area to optimize structural stability;

[0060] S4. Establish a thermo-mechanical-electric multi-field coupling model for the terminal structure, and optimize the current conduction, heat flow conduction and mechanical stress field of the conductor connection area, composite tube sleeve area, tail tube stress relief area and lattice cooperation area to achieve a balance of thermo-mechanical-electric coupling effect.

[0061] In step S1, when the structure is functionally partitioned and its configuration is planned, the performance requirements of each functional module of the terminal are analyzed, and it is divided into four functional areas: conductor connection area, composite sleeve area, lattice cooperation area and tail tube stress relief area. The conductor connection area, located at the top of the terminal structure, is responsible for the main tasks of current input / output and mechanical load transmission. This area requires high conductivity and mechanical strength, therefore, highly conductive metallic materials (such as copper alloys) are used, and a precisely designed geometry ensures the shortest current path and minimized resistance. The composite sleeve area, located below the conductor connection area, is mainly used to achieve electric field homogenization between the metallic conductor and the composite insulation system. The design of this area needs to consider the transition between conductivity and insulation properties to reduce stress concentration and thermal stress. The lattice coordination area, located in the middle and lower part of the terminal structure, is responsible for heat dissipation and mechanical support. By introducing a lattice structure, the heat flow and load path are optimized, reducing the overall mass while improving heat dissipation capacity. The design of the lattice coordination area must be optimized according to the direction of heat flow and load to ensure that the thermal conductivity and strength of the material can work synergistically. The tail tube stress relief area, located at the end of the terminal structure, is responsible for the dispersion and release of thermal and mechanical stress. High-strength materials and structural design are used to ensure the gradual release of stress, and multi-stage heat dissipation structure enhances heat dissipation efficiency, ensuring the deformation coordination and assembly stability of the overall structure.

[0062] In step S2, the structure and materials of the lattice coordination region include the structure, position, and material of the lattice component 4. By introducing adjustable lattice components 4 into the composite sleeve region and the tail tube stress relief region, the synergistic optimization of thermal conductivity, mechanical strength, and mass distribution is achieved by adjusting the unit shape, spatial arrangement, and density distribution. The shape and arrangement of each lattice unit are adjusted through parametric design, and the size and density of the unit gradually change along the axial direction, thereby achieving the optimal configuration of thermal conductivity and load-bearing capacity. The arrangement direction of the lattice structure is optimized according to the stress distribution and temperature rise gradient to ensure that the thermal conduction and load paths in different regions can be precisely aligned. Through the construction of parametric periodic units, the lattice structure effectively coordinates the coupling of multiple physical fields, including heat, force, and electricity. Specifically, the lattice component 4 is made of a high thermal conductivity metal material, and the porosity of the lattice unit gradually increases along the axial direction from the bottom of the composite sleeve 31 to the tail tube 6, optimizing the thermal conductivity and effectively reducing local temperature rise, avoiding thermal stress accumulation and stress concentration, thereby significantly improving thermal-mechanical stability and ensuring long-term reliability under high load and high current conditions.

[0063] In step S3, the composition of the metallic materials in the composite sleeve area and the tailpipe stress relief area is designed. A composite gradient metallic material is used, and the continuous change in material composition and properties along the axial direction ensures a smooth transition in thermal conductivity and mechanical properties. The gradual change in the material of the stress cone 34 module and the tailpipe 6 ensures a smooth transition of thermal stress, avoiding stress concentration and thus alleviating stress concentration caused by differences in thermal expansion coefficients between different materials, reducing the accumulation of thermal stress and fatigue damage. Through the continuous transition of material functions, the performance requirements of different areas are seamlessly integrated within a single system, significantly improving the stability and durability of the structure. In this embodiment, the tailpipe 6 and the stress cone 34 module are made of composite gradient metal materials. From the stress cone 34 module to the tailpipe 6, the conductivity of the tailpipe 6 decreases while its thermal conductivity increases, and the conductivity of the stress cone 34 module also decreases while its thermal conductivity increases. Specifically, the stress cone 34 module uses a copper-based composite gradient metal, with a copper alloy in the upper part and a copper-aluminum-magnesium alloy in the middle and lower parts. From top to bottom, the proportion of copper in the copper-aluminum-magnesium alloy gradually decreases, while the proportions of aluminum and magnesium gradually increase. The tailpipe 6 uses a copper alloy and aluminum-magnesium alloy composite gradient metal, with a copper alloy in the upper part and an aluminum-magnesium alloy in the middle and lower parts. From top to bottom, the proportions of aluminum and magnesium in the aluminum-magnesium alloy gradually increase. The tailpipe 6 undergoes a gradual change in material along the axial direction to achieve a balance between high conductivity and high strength. The gradient metal material achieves a uniform transition along the current path, solving the problem of poor contact between metal materials and significantly reducing stress concentration and thermal expansion mismatch. The volume fraction gradient of the metal modulates the hardness and conductivity of the material, enabling a smooth transition in the performance of the coupling region of multiple thermal, mechanical, and electrical fields, and maintaining the stability and reliability of the structure under high load and high current density conditions.

[0064] In step S4, after completing the collaborative design of the structure and materials of each functional area, a thermo-mechanical-electrical multi-field coupling model of the terminal structure is established to comprehensively optimize the coupling effects of the conductor connection area, composite sleeve area, and lattice coordination area. Through multi-field joint solution, the coupling law between current distribution, temperature field, and stress field is determined, and the global coordination of energy transfer and structural response is optimized by controlling the heat flow direction, stress path, and electric field distribution. By introducing multi-physics field coupling analysis, the interaction between current, electric field, temperature field, and stress field is comprehensively considered to optimize the current path and heat flow path, making the transfer of heat and electrical energy more uniform, thereby reducing local overheating and stress concentration. For each key area (conductor connection area, composite sleeve area, lattice coordination area, and tail tube stress relief area), local material properties and structural design are optimized, and these local optimization strategies are integrated through a global optimization algorithm to improve the overall system performance. By precisely controlling the material gradient or lattice design of each area, the limitations of optimizing the thermal, mechanical, and electrical fields separately in traditional design are overcome, significantly improving the thermal stability, mechanical reliability, and operational safety of the dry terminal. This comprehensive optimization process not only improved the current distribution and heat conduction path but also effectively mitigated the problems of uneven temperature gradients and stress concentration. Ultimately, it ensured the stable operation of the dry terminal under long-term high-load and high-temperature-difference environments.

[0065] When optimizing the overall structure for current conduction, heat flow conduction, and mechanical stress field, a thermo-mechanical-electric multi-field coupling model is adopted. The finite element method is combined with an adaptive optimization algorithm. By simulating the thermo-mechanical and electric multi-field coupling effects under different working conditions, the particle swarm optimization algorithm is used to adjust the current, temperature, and stress field in real time to ensure the high performance of the structure under high load and high current conditions.

[0066] The adaptive optimization algorithm employs an adaptive objective function algorithm. This algorithm is based on multi-physics coupling and dynamically adjusts the structural design through the following algorithmic process. The objective function is designed to consider the coordinated optimization of thermal, mechanical, and electric fields, and takes the following form:

[0067] Minimize: ;

[0068] Among them, f thermal f mechanical f electricalThese are optimization functions for heat, force, and electric fields, respectively; α, β, and γ are weighting coefficients that control the balance of heat conduction, mechanical properties, and electrical conductivity. Manufacturing constraints include material processing performance requirements, ensuring that the alloy used has good formability and high precision, while ensuring a stable supply of materials and meeting production process requirements. Current frequency testing and mechanical performance testing are conducted to verify the structure's stability and performance under high current density, as well as its mechanical properties and load-bearing capacity. The structure and materials of each region are optimized while meeting requirements, ensuring optimal paths for heat flow, force flow, and current transfer, and guaranteeing stability under high load and high temperature environments. In the composite sleeve region and the tail tube stress relief region, composite gradient metal materials are used to optimize the thermo-mechanical-electric multi-field coupling performance. In the lattice coordination region, the size and density of lattice units are adjusted, with the boundary size of lattice units controlled below 5mm. An arc-shaped design is used to fit the sleeve and other components, improving structural stability and heat conduction efficiency. Through parametric design, the tilt angle of lattice rods, cell size, and node density are adjusted to optimize heat flow paths, load-bearing capacity, and heat dissipation. By precisely controlling material distribution, structural geometry, and regional functional division, the stable operation of the terminal structure under high current, high temperature, and high load conditions is ensured.

[0069] The volume fraction and size of the lattice units are optimized based on mechanical load and thermal conductivity requirements, and dynamically adjusted using an adaptive optimization algorithm to ensure the coordinated action of thermal, mechanical, and electric fields. During lattice co-optimization, an adaptive lattice optimization algorithm is employed. This algorithm dynamically adjusts the size, porosity, and density of the lattice units by real-time monitoring of environmental parameters such as current, temperature, and stress. The adaptive design space expansion and contraction of this algorithm are based on a real-time environmental feedback mechanism and physical field optimization objectives. The specific formula is as follows:

[0070]

[0071] Among them, D ext The extended design space is represented by D0; the initial design space is represented by λ, μ, and ν, which are the weighting coefficients for the thermal, mechanical, and electric fields, respectively; f therma f mechanical f electricalThe optimization functions for the thermal, mechanical, and electric fields respectively reflect the influence of the corresponding physical fields on the expansion of the design space. The algorithm introduces a dynamic design space expansion mechanism, enabling the design parameters of the lattice units to adaptively expand or shrink when operating conditions change. Specifically, when current, temperature, or stress is high, the lattice units expand the design space, increasing porosity and size; when the load is light or the temperature is low, the design space shrinks, reducing porosity to ensure structural stability and strength. Through adaptive design, the design space expands or shrinks accordingly when the demands of the thermal, mechanical, and electric fields change, thus adapting to different operating environments and ensuring that the lattice structure achieves optimal performance under high current, high temperature, and high load conditions. During lattice optimization, the synergistic optimization among the thermal, mechanical, and electric fields is dynamically adjusted through the following feedback mechanism:

[0072]

[0073] Among them, f total It is the overall optimization objective function; f field,i Let α represent the optimization objectives for heat, force, and electric fields, respectively; i These are the weighting coefficients for heat, force, and electric fields, dynamically adjusted based on real-time data. During each optimization iteration, the weighting coefficients (α) are adaptively adjusted. i During the optimization process, the influence of each physical field on the design is updated in real time according to changes in the working environment. Finally, the optimization adjustment process fine-tunes the design parameters using the following formula:

[0074]

[0075] Where ΔD is the adjustment amount of the lattice unit design parameters; η is the adaptive adjustment coefficient, which ensures that the design parameters do not deviate excessively from the initial conditions during the optimization process.

[0076] In constructing the thermo-mechanical-electric multi-field coupling model, the finite element method is employed to model current conduction, heat flow conduction, and mechanical stress fields separately, and the interactions between these physical fields are solved through coupling. In the conductor connection region, the contact resistance is reduced by optimizing the current path, ensuring the shortest current flow path and minimizing resistance. In the composite sleeve region and the lattice cooperation region, the heat conduction path is optimized to improve heat dissipation efficiency. In the tail tube stress relief region, the stress field is optimized to reduce the accumulation of thermal stress and the concentration of mechanical stress. Through the multi-field coupling optimization process, the direction of heat flow, stress path, and electric field distribution are controlled to optimize the global coordination of energy transfer and structural response, thereby balancing the thermo-mechanical-electric coupling effect. By parametrically designing and adjusting the tilt angle, lattice size, and node density of the lattice members, the heat flow, mechanical flow, and current paths can be smoothly transmitted within each functional region. Through a thermo-mechanical-electric multi-field coupling model and comprehensive optimization process, the stable operation of the terminal equipment under high current, high temperature and high load conditions is ensured. The comprehensive optimization of conductivity efficiency, heat dissipation capacity and structural stability is achieved, while taking into account lightweighting and the synergistic optimization of thermo-mechanical-electric multi-physics fields.

[0077] This embodiment successfully achieves a high degree of integration in the structure, materials, and performance of the conductor connection area, composite sleeve area, tail tube stress relief area, and lattice coordination area through overall layout and functional coupling, ensuring the synergistic effect of each functional area. Introducing a lattice structure into the lattice coordination area significantly enhances heat dissipation capacity, optimizes the coupling between current conduction, heat flow paths, and mechanical paths, and reduces uneven loads caused by thermo-mechanical-electrical coupling. Introducing composite gradient metal materials into the composite sleeve area and tail tube stress relief area ensures high strength, excellent heat dissipation performance, and resistance to electrolytic corrosion, meeting the stringent requirements for lightweight and long lifespan under ultra-high voltage operating conditions. Through topology optimization and multiphysics collaborative design, the functions of each area are optimized and integrated, significantly improving the safety and efficiency of the terminal equipment under high current density conditions. The dry terminal structure and its design method in this embodiment not only focus on optimizing individual functions but also achieve breakthroughs in the collaborative optimization of material distribution, heat flow, and load paths, ensuring a balance of multiphysics coupling effects and improved overall performance.

[0078] The dry terminal structure and its design method in this embodiment are not limited to the parameter settings and material selections mentioned above. The gradient transition ratio, lattice unit size, material type, and assembly method in the structure can all be adjusted and expanded according to the size requirements and operating environment conditions of dry terminals at different voltage levels. For example, the gradient transition ratio can be optimized between different regions based on conductivity and thermal conductivity requirements; the lattice unit size can be adjusted according to heat flow and mechanical requirements to ensure effective transmission of heat and force flow paths; the thickness of the composite sleeve area can be adjusted to improve the stability and durability of the structure by optimizing the metallurgical bonding, ensuring the long-term stability of the functions of each region under high load and high temperature environments. The material type can be selected according to different voltage levels and operating conditions, using appropriate alloys or composite materials to achieve optimal conductivity, thermal stability, and mechanical strength; in terms of assembly method, considering actual manufacturing and usage conditions, mechanical fitting, chemical bonding, or other composite processes can be selected to ensure structural reliability and metallurgical bonding.

[0079] This design is particularly suitable for high current density conditions in the terminal connection and equipment transition zone of ultra-high voltage transmission lines, and can be widely used in fields such as high-voltage connectors, composite insulation transition components, and high-efficiency heat dissipation electrical interfaces in power systems. In practical applications, design parameters can be flexibly adjusted according to the size requirements and environmental conditions of different terminals to achieve synergistic optimization of the conductivity, heat dissipation, and insulation performance of ultra-high voltage dry-type terminals, thereby ensuring their stable operation under long-term, high-load, and high-temperature environments.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dry-type terminal structure for ultra-high voltage transmission, characterized in that: The device includes a conductor connection region, a composite sleeve region, a tail tube stress relief region, and a lattice coordination region. The conductor connection region includes an upper component and a conductor connecting rod. The composite sleeve region includes a composite sleeve assembly. The tail tube stress relief region includes a tail tube and a supporting insulator arranged around the tail tube. The upper component, the composite sleeve assembly, and the tail tube are connected sequentially from top to bottom. The conductor connecting rod passes through the upper component, the composite sleeve assembly, and the tail tube sequentially along the axial direction. The lattice coordination region includes a lattice assembly for enhanced heat dissipation. The lattice assembly is sleeved around the bottom of the composite sleeve assembly and / or around the tail tube.

2. The UHV dry-type terminal structure as described in claim 1, characterized in that: The composite sleeve assembly includes a composite sleeve and a stress cone module disposed within the composite sleeve. The top and bottom of the composite sleeve are sealed by the upper end assembly and the stress cone module, respectively. The cavity of the composite sleeve is filled with silicone oil. The tail tube is connected to the stress cone module, and the lattice assembly is sleeved around the tail tube and / or the bottom of the composite sleeve.

3. The UHV dry-type terminal structure as described in claim 2, characterized in that: The upper component and the conductor connecting rod are both made of high conductivity metal material; the tail tube and the stress cone module are made of composite gradient metal material, and from top to bottom, the conductivity of the tail tube and the stress cone module decreases and the thermal conductivity increases; the lattice component is made of high thermal conductivity metal material.

4. The UHV dry-type terminal structure as described in claim 3, characterized in that: The stress cone module is made of copper-based composite gradient metal, with copper alloy in the upper part and copper-aluminum-magnesium alloy in the middle and lower parts. From top to bottom, the proportion of copper in the copper-aluminum-magnesium alloy gradually decreases, while the proportions of aluminum and magnesium gradually increase.

5. The UHV dry-type terminal structure as described in claim 3, characterized in that: The tailpipe is made of a copper alloy and an aluminum-magnesium alloy composite gradient metal, with the upper part made of copper alloy and the middle and lower parts made of aluminum-magnesium alloy. The proportion of aluminum and magnesium in the aluminum-magnesium alloy gradually increases from top to bottom.

6. The UHV dry-type terminal structure as described in claim 3, characterized in that: The lattice assembly, the stress cone module, and the tail tube are all formed by laser powder bed melting process.

7. The UHV dry-type terminal structure as described in claim 6, characterized in that: During the printing process of the lattice component, the porosity and rod diameter can be programmably varied by dynamically adjusting the energy density, scanning spacing and layer thickness parameters; during the printing process of the stress cone module and the tail tube, the material gradient can be achieved by dynamically adjusting the material composition and layer thickness parameters.

8. The UHV dry-type terminal structure as described in claim 1, characterized in that: The lattice assembly includes a composite tube sleeve region lattice assembly sleeved around the bottom periphery of the composite tube sleeve assembly and a tail tube stress relief region lattice assembly sleeved around the tail tube. Both the composite tube sleeve region lattice assembly and the tail tube stress relief region lattice assembly are formed by lattice units arranged along the axial and circumferential directions.

9. The UHV dry-type terminal structure as described in claim 8, characterized in that: The porosity of the lattice units in the lattice assembly gradually increases from top to bottom.

10. A design method for an ultra-high voltage dry-type terminal structure according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Based on the operating characteristics of UHV dry-type terminals under high voltage, high load and high heat flux density conditions, the structure is functionally partitioned and configured, and divided into conductor connection area, composite sleeve area, tail tube stress relief area and lattice cooperation area. S2. Design the structure and materials of the lattice coordinating region to optimize thermal conductivity and mechanical properties; S3. Design the structure and materials of the composite sleeve area and the tailpipe stress relief area to optimize structural stability; S4. Establish a thermo-mechanical-electric multi-field coupling model for the terminal structure, and optimize the current conduction, heat flow conduction and mechanical stress field of the conductor connection area, composite sleeve area, tail tube stress relief area and lattice cooperation area to balance the thermo-mechanical-electric coupling effect.

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