Clean air insulated high-voltage bushing

Abstract

The invention discloses a high-voltage bushing for clean air insulation. The high-voltage bushing comprises a bushing, a transition flange, a wiring terminal board, a connecting conductor, a bushing shielding case, a conductor shielding case, a transition conductor, a contact seat assembly and a bushing base assembly, an internal insulating medium of the sleeve is clean air; the connecting conductor is an aluminum conductor and extends into the sleeve base assembly to be transited into a copper conductor, and the transition position of a conductor material is arranged in a tank body of the sleeve base assembly; the wiring terminal board and the connecting conductor are of an integrated welding structure, and the bottom of the wiring terminal board is provided with a threaded hole and is assembled and plugged with the contact seat through the transition conductor; flanges at the two ends of the sleeve are provided with a plurality of sets of arc-shaped diagonal braces, and the diagonal braces and the flanges are of an integrated casting structure and used for optimizing electric field distribution and enhancing heat dissipation capacity. The conductor shielding cover covers the transition joint of the aluminum conductor and the copper conductor and is fixed on the transition conductor through a sunk screw; four circles of spring contact fingers are arranged in the contact seat assembly and are used for reducing plugging resistance and temperature rise.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage switches, and particularly relates to a high-voltage bushing insulated by clean air. Background Art

[0002] SF6 gas is widely used in the power system due to its excellent insulation performance and arc extinguishing ability. As an excellent insulating gas, SF6 has had a profound impact on the development of the power industry, bringing both positive contributions and challenges. SF6 gas has a strong greenhouse effect, and its global warming potential (GWP) is approximately 23,500 times that of carbon dioxide. Internationally, the Paris Agreement requires countries to reduce greenhouse gas emissions. The European Union has restricted the use of SF6 gas in some equipment, and the United States, Japan, etc. are promoting the reduction of the use of SF6 gas. Moreover, the decomposition products of SF6 gas under the arc are harmful, and the recycling and treatment costs are relatively high. Reducing the use of SF6 gas helps to protect environmental safety and public health. Replacing SF6 gas with environmentally friendly gases is of great significance in responding to global climate change, complying with international laws, improving economic benefits, and promoting social progress.

[0003] Reducing the use of SF6 is an important measure to achieve sustainable development. At present, the State Grid has begun to promote the application of high-voltage switchgear with environmentally friendly gases. As an important part of high-voltage switches, a high-voltage bushing with an environmentally friendly gas as the dielectric is urgently needed in the current high-voltage switch industry. Summary of the Invention

[0004] To achieve the above and other related purposes, the present invention discloses a high-voltage bushing insulated by clean air, including a bushing, a transition flange, a terminal board and a connecting conductor, a bushing shield, a conductor shield, a transition conductor, a contact seat assembly, and a bushing base assembly; The internal insulating medium of the bushing is clean air; The connecting conductor is an aluminum conductor, which extends into the bushing base assembly and transitions to a copper conductor, and the conductor material transition position is arranged in the tank body of the bushing base assembly; The terminal board and the connecting conductor are of an integral welded structure, and a threaded hole is provided at the bottom thereof and is inserted into the contact seat assembly through a transition conductor; Multiple groups of arc-shaped stay bars are provided on the flanges at both ends of the bushing, and the stay bars and the flanges are of a cast integral structure, which is used to optimize the electric field distribution and enhance the heat dissipation capacity; The conductor shield covers the transition connection of the aluminum conductor and the copper conductor and is fixed to the transition conductor by countersunk head screws; Four circles of spring fingers are arranged in the contact seat assembly to reduce the insertion resistance and temperature rise.

[0005] Furthermore, the transition conductor is made of copper, its insertion part is silver-plated, and its non-insertion part is provided with ventilation holes to enhance the heat dissipation efficiency.

[0006] Furthermore, the transition flange is internally provided with an arc-shaped closing structure and a sleeve shielding cover is installed. There are two sealing grooves on both sides. The outer sealing groove is configured with a waterproof ring, and the inner sealing groove is configured with an air chamber sealing ring.

[0007] Furthermore, a hemispherical tank body is welded to the top of the main cylinder assembled by the sleeve base, and the diameters of the three-phase support cylinders are enlarged to increase the inner cavity space.

[0008] Furthermore, the connecting conductor is of an annular tubular structure, and a plurality of groups of heat dissipation holes are provided all around.

[0009] Furthermore, a guide ring is provided at the upper mouth of the contact seat assembly to ensure the dimensional accuracy of the inserted conductor.

[0010] Furthermore, the sleeve shielding cover and the conductor shielding cover are both made of aluminum, and their shapes and sizes are optimized through electric field calculation.

[0011] Furthermore, the sleeve is made of porcelain, and the two end flanges are made of cast aluminum alloy and are integrally sintered and formed.

[0012] Furthermore, the housing material of the sleeve base assembly is welded aluminum alloy, and the conductor and contact seat materials are aluminum alloy.

[0013] By adopting the above technical solutions, the present invention realizes environmental friendliness by using clean air as the insulating medium, avoids the environmental pollution and greenhouse effect of traditional SF6 gas, and at the same time combines the transition design of aluminum conductor and copper conductor to optimize the conductivity and heat dissipation performance of the conductor. The one-piece welding structure reduces the number of butt joints to reduce the connection resistance and temperature rise, enhances the mechanical strength and installation efficiency, uses the arc-shaped diagonal stay design of the sleeve flange to optimize the electric field distribution and improve the heat dissipation capacity, covers the conductor transition and flange interface with a shielding cover to improve the electric field uniformity and reduce the local field strength concentration, and the enlarged inner cavity space design of the sleeve base further improves the insulation performance and heat dissipation efficiency. The use of aluminum alloy material and porcelain sleeve structure reduces the equipment weight and material cost while ensuring the mechanical strength. The spring finger and guide ring design of the contact seat assembly effectively reduces the insertion resistance and ensures the installation accuracy. The overall structure is simplified, reducing the number of parts and production complexity, improving the operation stability and maintenance convenience of the equipment, and finally achieving the comprehensive technical effects of environmental protection, high insulation, low energy consumption, low cost and high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In conjunction with the accompanying drawings and with reference to the following detailed description, the above and other features, advantages, and aspects of the embodiments of the present disclosure will become more apparent. The drawings are used to better understand the solution and do not limit the present disclosure. In the drawings, the same or similar reference numerals represent the same or similar elements, where: Figure 1 is a schematic cross-sectional view of the present invention.

[0015] Reference numerals: 1, bushing; 2, transition flange; 3, terminal board and connecting conductor; 4, bushing shield; 5, conductor shield; 6, transition conductor; 7, contact seat assembly; 8, bushing base assembly. Detailed implementation manners

[0016] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts belong to the scope of protection of the present invention.

[0017] Referring to Figure 1 , an embodiment of the present invention provides a high-voltage bushing 1 with clean air insulation, including a bushing 1; a transition flange 2; a terminal board and a connecting conductor 3; a bushing shield 4; a conductor shield 5; a transition conductor 6, a contact seat assembly 7, and a bushing base assembly 8.

[0018] The bushing 1 is hermetically connected to the bushing 1 base through the sealing grooves and threaded holes on both sides of the transition flange 2. The terminal board and the connecting conductor 3 are of an integral structure and are hermetically connected to the bushing 1 through the sealing groove on the top circular flange. The bushing shield 4 is fixed using the threaded holes inside the transition flange 2. The conductor shield 5 is fixed using the threaded holes outside the transition conductor 6. The transition conductor 6 is fastened and conducted through the threaded holes at the bottom of the terminal board and the connecting conductor 3. The contact seat assembly 7 is connected to the conductor of the bushing 1 base by means of bolt connection. The terminal board and the connecting conductor 3 are docked with the bushing 1 base and are conducted through the guide ring and spring contact finger inside the contact seat assembly 7.

[0019] The material of the bushing 1 is porcelain. The flanges at both ends of the bushing 1 are cast aluminum alloy. The whole is sintered integrally to enhance the strength, sealing performance and stability of the bushing 1. The size and umbrella combination, size and strength of the porcelain bushing 1 meet the performance requirements. Since the thermal conductivity of the material of the porcelain bushing 1 itself is poor, and the bushing 1 is a part with a relatively high temperature rise in the high-voltage switchgear, and the clean air medium increases the difficulty of heat dissipation and insulation of the bushing 1, so there are multiple groups of arc-shaped inclined ribs on the outer ring of the flanges at both ends, which not only serve as reinforcing ribs to increase the strength of the flanges, but also play the role of heat sinks. The inclined ribs and the flanges are of a cast integral structure. The arc-shaped heat sinks increase the surface area of the exposed metal of the flange of the bushing 1, improve the heat exchange efficiency, and make the overall shape of the external flange connection position of the bushing 1 present a smooth transition. This flange structure of the bushing 1 can, through calculation, play the role of an end grading ring, simplify the structure of the bushing 1, and reduce the cost; the flange of the bushing 1 is provided with evenly distributed bolt holes and a sealing surface for the butt joint of the bushing 1 and the terminal board and the base of the bushing 1.

[0020] The transition flange 2 realizes the transition and connection of the dimensional changes between the bushing 1 and the base of the bushing 1. The material is aluminum alloy. The two sides of the flange are M12 threaded blind holes that are staggered and evenly distributed, ensuring the firm installation of the bushing 1. And there are two sealing grooves on each side of the flange. A waterproof ring is equipped in the outer sealing groove to limit the moisture content in the gas chamber, thereby improving the insulation performance. An air chamber sealing ring is equipped in the inner sealing groove to ensure the sealing of the air chamber; a circular machined surface and threaded holes are provided on the upper side inside the flange for the installation of the shielding cover at the interface of the bushing 1. The lower side is a large R fillet to optimize the electric field of the interface and the conductor on the opposite side and increase the insulation performance.

[0021] The flange of the terminal board and the connecting conductor are welded integrally, reducing the butt joint surface of the conductor inside the bushing 1 and reducing the connection resistance. This structure can effectively simplify the product installation steps and reduce the temperature rise of the bushing 1. The top flange is equipped with installation bolt holes and a sealing groove, and is hermetically connected to the bushing 1. The internal tubular conductor is made of aluminum, reducing the equipment weight. The annular cross-section increases the material utilization rate and the heat dissipation area of the conductor. There are multiple groups of small heat dissipation holes around the conductor to enhance the heat exchange inside and outside the conductor. The bottom end face is silver-plated and provided with threaded holes for the connection of the transition conductor 6.

[0022] To reduce the equipment weight, the material of the bushing shielding cover 4 is aluminum. There are bolt holes at the bottom for fixing the shielding cover. The diameter, height and top shape of the bushing shielding cover 4 are all obtained through electric field calculation. It can effectively shield the local field strength increase caused by dimensional changes. The bushing shielding cover 4 improves the heat distribution while evenly distributing the electric field and improves the heat dissipation efficiency. Because the internal conductor transition position is outside the bushing 1 and there is no dimensional mutation in the conductor inside the bushing 1, so only the bushing shielding cover 4 can ensure that the field strength is qualified at the butt joint position of the bushing 1, greatly simplifying the structure here and increasing the equipment stability.

[0023] The conductor shielding cover 5 is made of aluminum and is used to shield the diameter change at the transition point between the aluminum conductor and the copper conductor. There are four evenly distributed bolt holes on the side of the conductor shielding cover 5, which are fastened with four countersunk screws to make a smooth transition between the conductor and the surface of the conductor shielding cover 5. Thanks to the design that the transition position of the conductor material is located inside the tank body of the base of the bushing 1, this conductor shielding cover 5 has a small structure and is easy to install, so that the field strength of the conductor of the bushing 1 can meet the performance requirements and retain sufficient margin.

[0024] In order to reduce the temperature rise caused by the conductor plugging at the interface of the bushing 1, the transition conductor 6 is made of copper, which has better conductivity, lower resistance and stronger heat dissipation capacity than aluminum conductors. While ensuring temperature rise and insulation, the length and diameter of the copper conductor are minimized, thereby reducing product weight and material costs. There are four threaded holes on the top side for the installation of the conductor shielding cover 5. At the same time, bolt through holes in the upper and lower directions are provided at the positions of the shielding cover mounting holes, which are used for bolt fastening between this conductor and the aluminum conductor. The end face where the top diameter increases is silver-plated to increase the docking area and reduce the docking resistance. The lower plug-in position is a machined surface and is silver-plated to ensure good contact at the plug-in position. A number of ventilation holes for heat dissipation are provided at the non-plug-in position of the conductor to further increase the heat dissipation efficiency.

[0025] The contact seat is assembled 7 in the base of the bushing 1. There are three bolt holes at the bottom. The bolt heads are sunk into the holes. The inner cavity depth of the contact seat is calculated by the dimension chain to leave enough space for the plug-in conductor so that the installation is not affected by the dimensional changes caused by the tolerance of the parts and the shrinkage and thermal expansion. The upper mouth of the contact seat is a guide ring to ensure the accurate insertion size of the conductor. The plug-in point is set to four turns of spring contact fingers through temperature rise calculation, and the number of turns of each spring contact finger is guaranteed at the same time to ensure that the temperature rise of the contact seat meets the performance requirements.

[0026] The base of bushing 1 is mainly composed of a pot-type insulator, a shell, a conductor, and a contact seat. The shell is connected to the pot-type insulator of the equipment busbar through the bolt holes on the main barrel flange, and is connected to the three-phase bushing 1 through the bolt holes on the three-phase support barrel through the transition flange 2. The conductor is connected to the insert conductor on the pot through the connecting bolts, and the contact seat and the conductor are connected by bolt connection. The pot-type insulator material is epoxy resin with a metal flange to enhance mechanical strength and corrosion resistance. The conductor and contact seat material is aluminum alloy, and the shell material is welded aluminum alloy. The low density of aluminum alloy is conducive to reducing product weight. Half of the spherical tank is welded on the top of the main barrel, and the diameter of the three-phase support barrel is as large as possible while meeting the welding distance, so that the inner cavity space of the bushing 1 base can be sufficient, which is conducive to insulation and heat dissipation performance.

[0027] Although some specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and not for limiting the scope of the present invention. Those skilled in the art should also understand that various modifications can be made to the embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A high-voltage bushing with clean air insulation, characterized in that, It includes a bushing, a transition flange, a terminal board, a connecting conductor, a bushing shield, a conductor shield, a transition conductor, a contact seat assembly, and a bushing base assembly; The internal insulating medium of the bushing is clean air; The connecting conductor is an aluminum conductor, which extends into the bushing base assembly and transitions to a copper conductor, and the conductor material transition position is set inside the tank body of the bushing base assembly; The terminal board and the connecting conductor are of an integral welded structure, with threaded holes at the bottom and are inserted into the contact seat assembly through the transition conductor; The flanges at both ends of the bushing are provided with multiple groups of arc-shaped stay bars, and the stay bars and the flanges are of an integral casting structure, which is used to optimize the electric field distribution and enhance the heat dissipation capacity; The conductor shield covers the transition connection of the aluminum conductor and the copper conductor and is fixed to the transition conductor by countersunk head screws; Four circles of spring fingers are arranged inside the contact seat assembly to reduce the insertion resistance and temperature rise; 2. The high-voltage bushing with clean air insulation according to claim 1, wherein The material of the transition conductor is copper, its insertion part is silver-plated, and vent holes are provided at non-insertion parts to enhance the heat dissipation efficiency; 3. The high-voltage bushing with clean air insulation according to claim 1, wherein The transition flange is internally provided with an arc-shaped closing structure and a bushing shield is installed. Two sealing grooves are respectively provided on both sides. A waterproof ring is configured in the outer sealing groove, and a gas chamber sealing ring is configured in the inner sealing groove; 4. The high-voltage bushing with clean air insulation according to claim 1, characterized in that, The top of the main cylinder of the bushing base assembly is welded with a hemispherical tank body, and the diameters of the three-phase support cylinders are enlarged to increase the internal cavity space; 5. The high-voltage bushing with clean air insulation according to claim 1, characterized in that, The connecting conductor is of an annular tubular structure, and multiple groups of heat dissipation holes are provided on the whole body; 6. The high-voltage bushing with clean air insulation according to claim 1, characterized in that, A guiding ring is provided at the upper opening of the contact seat assembly to ensure the dimensional accuracy of the inserted conductor; 7. The high-voltage bushing with clean air insulation according to claim 1, characterized in that, The materials of the bushing shield and the conductor shield are both aluminum, and their shapes and sizes are optimized through electric field calculation; 8. The high-voltage bushing with clean air insulation according to claim 1, characterized in that, The material of the bushing is porcelain, and the flanges at both ends are cast aluminum alloy and are integrally sintered and formed; 9. The high-voltage bushing with clean air insulation according to claim 1, characterized in that, The shell material of the bushing base assembly is welded aluminum alloy, and the materials of the conductor and the contact seat are aluminum alloy.

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