Vacuum circuit breaker taking synthetic air as insulating medium

Abstract

The invention discloses a vacuum circuit breaker taking synthetic air as an insulating medium, and the circuit breaker comprises a housing which is internally provided with a sealed air cavity, and the air cavity is filled with synthetic air with rated pressure; the three phase columns are arranged in the inner cavity of the shell in a triangular shape, and each phase column comprises a vacuum arc extinguish chamber, a movable side insulation support, a static side insulation support, an upper outlet conductor and a lower outlet conductor; the transmission structure is installed in the top cover and comprises a transmission shaft, a connecting rod, a spring assembly and a triangular bracket, the transmission shaft is connected with the output shaft of the operating mechanism through the connecting rod, and three corners of the triangular bracket are connected with the insulating pull rods of the three-phase column respectively; the operating mechanism is used for outputting a rotating torque to drive the transmission structure and drive the insulating pull rod to realize opening and closing actions of the vacuum arc-extinguishing chamber; the synthetic air comprises 20.5% of oxygen and 79.5% of nitrogen, and the rated pressure in the air cavity is configured to improve the insulating property of the synthetic air.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage switches, and particularly to a vacuum circuit breaker using synthetic air as an insulating medium. Background Art

[0002] As a gas with excellent arc extinguishing and insulating properties, SF6 gas is widely used in the power industry. It is mainly used as an arc extinguishing medium for high-voltage switchgear or as an insulating medium for gas-insulated combined electrical equipment in the power industry. It is estimated that the demand for SF6 gas in the Chinese power industry exceeds 10,000 tons. However, SF6 gas is also a strong greenhouse gas, and its global warming potential index is 23,900 times that of carbon dioxide, which is a greenhouse gas clearly restricted by the Kyoto Protocol. Currently, for the alternative solutions to SF6 gas, mainly SF6 alternative gases (such as C4F7N, C3F8, CF4, etc.) are used as arc extinguishing and insulating media. These new environmentally friendly gases show good dielectric properties and environmental protection potential, but there are problems such as complex decomposition products during the gas decomposition process and the impact on the insulation ability of the equipment itself, and they fail to achieve carbon-free and fluorine-free. Summary of the Invention

[0003] To achieve the above and other related purposes, the present invention discloses a vacuum circuit breaker using synthetic air as an insulating medium, including: A housing, which forms a sealed gas chamber inside, and the gas chamber is filled with synthetic air at a rated pressure; Three-phase phase columns, arranged in a triangular shape in the inner cavity of the housing. Each phase column includes a vacuum arc extinguishing chamber, a moving-side insulating support, a static-side insulating support, an upper outlet conductor, and a lower outlet conductor; A transmission structure, installed inside the top cover, including a transmission shaft, a connecting rod, a spring assembly, and a triangular bracket. The transmission shaft is connected to the output shaft of the operating mechanism through the connecting rod, and the three corners of the triangular bracket are respectively connected to the insulating tie rods of the three-phase phase columns; An operating mechanism, used to output a rotational torque to drive the transmission structure and drive the insulating tie rods to realize the opening and closing actions of the vacuum arc extinguishing chamber; The synthetic air has a composition of 20.5% oxygen and 79.5% nitrogen, and the rated pressure in the gas chamber is configured to improve the insulating performance of the synthetic air.

[0004] Further, the housing is connected to the bottom cover and the top cover through bolts, and is provided with an O-ring for end face sealing to form an airtight gas chamber.

[0005] Further, both the moving-side insulating support and the static-side insulating support are integrally cast using epoxy resin material. The upper insert of the moving-side insulating support is fixed to the top plate, and the lower insert of the static-side insulating support is fixed to the bottom cover.

[0006] Further, the moving end of the vacuum interrupter includes a moving contact rod, the cylindrical surface of the moving contact rod is provided with an external thread, which is meshed and fixed with the internal thread of the wheel-shaped contact, and the upper end of the moving contact rod is connected to the internal thread hole of the insulating pull rod through a stud.

[0007] Further, the outer cylindrical surface of the wheel-shaped contact is provided with a U-shaped groove and a rectangular groove. A spring contact is installed in the U-shaped groove, and a guide ring is installed in the rectangular groove. The spring contact is in sliding contact with the inner wall of the upper outlet conductor.

[0008] Further, the bottom cover is an outwardly convex casting structure, and the inner wall is provided with a casting boss. The static-side insulation supports of the three-phase columns are fixed to the boss through bolts.

[0009] Further, a direct-acting sealing structure is provided between the transmission rod and the top cover, and the spring assembly is in a pre-compressed state to ensure the synchronism of the opening and closing operations.

[0010] Further, the layout forms of the outlet conductors include Z-shaped, U-shaped, T-shaped or double-outlet types, which are realized by adjusting the installation forms of the phase-column conductors.

[0011] Further, the static end of the vacuum interrupter is fixed to the lower outlet conductor through bolts, and the right end of the lower outlet conductor is connected to the right-side outlet conductor.

[0012] Further, the output shaft of the operating mechanism drives the transmission shaft to move directly through a connecting rod, and drives the triangular bracket to synchronously control the opening and closing of the three-phase columns.

[0013] By adopting the above technical solutions, synthetic air is used as the insulating medium, effectively avoiding the greenhouse effect of traditional SF6 gas on the environment, meeting international environmental protection requirements. At the same time, by optimizing the composition ratio of synthetic air and increasing the rated pressure, the reliability and stability of the insulation performance are ensured; the three-phase columns adopt a triangular layout structure, making the electric field distribution uniform and improving the space utilization rate. Combined with the design of the triangular bracket in the transmission structure, the precise synchronization of the three-phase opening and closing operations is realized, improving the stability and response efficiency of the circuit breaker operation; the moving-side and static-side insulation supports are integrally cast with epoxy resin, significantly enhancing the insulation isolation performance and mechanical strength, ensuring the durability and safety of the long-term operation of the equipment; the wheel-shaped contact is combined with the spring contact and the guide ring design to ensure stable contact pressure and precise guidance during current conduction, reducing the arc risk and improving the conductivity reliability; the bottom cover adopts an outwardly convex casting structure, effectively resisting deformation under high gas pressure and ensuring the overall structural stability; various outlet conductor layout forms and modular interface designs greatly improve the adaptability of the equipment to different engineering scenarios and reduce the installation complexity; the fully sealed structure design combined with the direct-acting sealing component prevents gas leakage and maintains the long-term stability of the insulation environment, comprehensively realizing the functions of an environmentally friendly, efficient and reliable high-voltage switchgear. Description of the Drawings

[0014] In combination 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 accompanying drawings are used to better understand the solution and do not limit the present disclosure. In the drawings, the same or similar reference numerals denote the same or similar elements, where: Figure 1 is a schematic cross-sectional view of the present invention.

[0015] Reference numerals: 1, housing; 2, phase column; 3, bottom cover; 4, top cover; 5, transmission structure; 6, operating mechanism; 7, top plate; 201, moving-side insulation support; 202, upper outlet conductor; 203, insulating pull rod; 204, wheel-shaped contact; 205, plate; 206, spring contact; 207, guide ring; 208, vacuum interrupter; 209, lower outlet conductor; 210, static-side insulation support; 501, transmission shaft; 502, connecting rod; 503, spring assembly; 504, triangular bracket; 601, output shaft. Detailed Description of the Embodiments

[0016] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in combination 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 creative efforts belong to the scope of protection of the present invention.

[0017] Referring to Figure 1 , the embodiments of the present invention provide a vacuum circuit breaker using synthetic air as an insulating medium. The vacuum circuit breaker of the present invention mainly includes a housing 1, a phase column 2, a bottom cover 3, a top cover 4, a transmission structure 5, and an operating mechanism 6.

[0018] The housing 1 has 4 identical standard interfaces, and other components can be selected and installed according to different engineering layout conditions. For details, refer to the engineering layout plan. The housing 1 and the bottom cover 3, and the housing 1 and the top cover 4 are connected by bolts, and end-face-sealed O-ring seals are respectively provided between the housing 1 and the bottom cover 3, and the housing 1 and the top cover 4 to form a complete air cavity. Synthetic air with a rated pressure is filled in the air cavity, and the composition of the synthetic air is 20.5% oxygen and 79.5% nitrogen. To improve the insulation performance of the synthetic air, the rated pressure of the synthetic air needs to be appropriately increased for the products of the present invention.

[0019] The phase columns 2 are divided into three phases: A, B, and C. The structures of the three-phase columns 2 are exactly the same. The three-phase columns 2 are arranged together in the inner cavity of the housing 1 in a triangular layout, such that the minimum distances between the three-phase columns 2 of phases A, B, and C and between the three-phase columns 2 of phases A, B, and C and the inner wall of the housing 1 are basically the same. In this way, the electric field lines of the high-voltage live parts of the three-phase columns 2 of phases A, B, and C can be evenly distributed, and the space of the inner cavity of the housing 1 can be utilized more evenly and fully.

[0020] The bottom end of the phase column 2 is fixedly connected to the bottom cover 3, and the top end of the phase column 2 is connected to the transmission structure 5 and the top plate 7.

[0021] The transmission structure 5 is installed inside the top cover 4. The transmission shaft 501 of the transmission structure 5 passes through the top cover 4 and is connected to the output shaft 601 of the operating mechanism 6 through a connecting rod 502. The operating mechanism 6 outputs a rotational torque to drive the connecting rod 502 to swing, and the connecting rod 502 then drives the transmission rod to move linearly. While the transmission rod passes through the top cover 4 and moves linearly and slidably, a linear motion sealing structure is provided between the transmission rod and the top cover 4 to ensure the airtight performance of the air cavity of the housing 1.

[0022] A spring assembly 503 is installed below the transmission rod, and the spring is always in a pre-compressed state. A triangular bracket structure is installed below the spring assembly 503. The three corners of the triangular bracket 504 are respectively connected to the insulating pull rods 203 of the three-phase columns 2 of phases A, B, and C, driving the insulating pull rods 203 of the three-phase columns 2 to open and close, and meeting the requirement of the synchronism of the opening and closing actions of the three-phase columns 2.

[0023] The insulating pull rod 203 passes through the moving-side insulating support 201 at the upper end of the phase column 2 and is connected to the moving end of the vacuum interrupter 208. The moving-side insulating support 201 is integrally cast and processed from an upper insert, a lower insert, and an epoxy resin material, and is used for connection and support. The upper insert of the moving-side insulating support 201 is fixedly installed on the top plate 7 with bolts, and the top plate 7 is fixedly installed on the lifting lug inside the housing 1. The lower insert of the moving-side insulating support 201 is installed with the upper outlet conductor 202 using bolts. The epoxy resin material has good insulation performance and can reliably separate the charged upper outlet conductor 202 from the non-charged top plate 7 and the housing 1.

[0024] The two ends of the vacuum interrupter 208 assembly are respectively a static end and a moving end. The moving end mainly consists of a moving contact rod and a fixed flange. The moving contact rod can drive the contact structure inside the interrupter to realize the opening and closing of the interrupter. The fixed flange is coaxial with the moving contact rod and can play a guiding role during the movement of the moving contact rod. A guiding plate is installed above the fixed flange. The cylindrical surface of the moving contact rod of the vacuum interrupter 208 has threads and is fixedly connected to the wheel-shaped contact 204 to realize the conduction of current. The upper end surface of the moving contact rod is a stud structure, and the stud is installed in the internal threaded hole of the insulating pull rod 203 and is locked with a nut to prevent loosening. The conductive system and the transmission system of the moving contact rod are separately arranged and do not affect each other.

[0025] The inner cylindrical surface of the wheel-shaped contact 204 has an internal thread structure and is fixedly engaged with the external thread of the moving contact rod. Two U-shaped grooves for installing the spring contact 206 and two rectangular grooves for installing the guide ring 207 are machined on the outer cylindrical surface of the wheel-shaped contact 204. The spring contact 206 is installed in the U-shaped groove and moves together with the wheel-shaped contact 204, and makes sliding contact with the inner wall of the upper outlet conductor 202. Since the spring contact 206 has a certain compression amount in the cross-sectional direction, a certain contact pressure is maintained between the spring contact 206, the U-shaped groove and the upper outlet conductor 202, and the current-carrying requirement can be well achieved. The left end of the upper outlet conductor 202 is connected to the left outlet conductor of the vacuum circuit breaker.

[0026] The static end of the vacuum interrupter 208 is fixed to the lower outlet conductor 209 by bolts, and the right end of the lower outlet conductor 209 is connected to the right outlet conductor of the vacuum circuit breaker.

[0027] The lowermost end of the phase column 2 is the static-side insulation support 210. The static-side insulation support 210 is integrally cast and processed from an upper insert and a lower insert using epoxy resin material, and is used to fixedly support the entire phase column 2. The lower insert of the static-side insulation support 210 is fixedly installed on the bottom cover 3 by bolts, and the upper insert is used to install the lower outlet conductor 209 by bolts. The epoxy resin material has good insulation performance and can reliably separate the charged lower outlet conductor 209 from the non-charged bottom cover 3.

[0028] The bottom cover 3 is of a casting structure and has an outward convex shape. Since the rated gas pressure of the product of the present invention is relatively high, in order to reduce the influence of the deformation of the bottom cover 3 after inflation on the phase column 2 and considering the cost of the bottom cover 3, the outward convex structure is adopted. The inner wall of the bottom cover 3 is cast with bosses for installing the three-phase phase columns 2, and is machined after casting to ensure the flatness of the three-phase bosses. 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 only for the purpose of illustration and not for the purpose of 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 vacuum circuit breaker with synthetic air as the insulating medium, characterized in that, Comprising: A housing (1) with a sealed air chamber formed inside, and synthetic air at a rated pressure is filled in the air chamber; Three-phase phase columns (2) arranged in a triangle in the inner cavity of the housing. Each phase column includes a vacuum interrupter (208), a moving-side insulating support (201), a static-side insulating support (210), an upper outlet conductor (202), and a lower outlet conductor (209); A transmission structure (5) installed inside the top cover (4), including a transmission shaft (501), a connecting rod (502), a spring assembly (503), and a triangular bracket (504). The transmission shaft is connected to the output shaft (601) of the operating mechanism (6) through the connecting rod (502), and the three corners of the triangular bracket (504) are respectively connected to the insulating tie rods (203) of the three-phase phase columns; An operating mechanism (6) for outputting a rotational torque to drive the transmission structure and drive the insulating tie rod (203) to achieve the opening and closing actions of the vacuum interrupter; The composition of the synthetic air is 20.5% oxygen and 79.5% nitrogen, and the rated pressure in the air chamber is configured to improve the insulation performance of the synthetic air.

2. The vacuum circuit breaker according to claim 1, wherein The housing (1) is bolted to the bottom cover (3) and the top cover (4), and is provided with an O-ring for end face sealing to form an airtight air chamber.

3. The vacuum circuit breaker according to claim 1, characterized in that, Both the moving-side insulating support (201) and the static-side insulating support (210) are integrally cast from epoxy resin material. The upper insert of the moving-side insulating support is fixed to the top plate (7), and the lower insert of the static-side insulating support is fixed to the bottom cover (3).

4. The vacuum circuit breaker according to claim 1, characterized in that, The moving end of the vacuum interrupter (208) includes a moving contact rod. The cylindrical surface of the moving contact rod is provided with an external thread, which is meshed and fixed with the internal thread of the wheel-shaped contact (204), and the upper end of the moving contact rod is connected to the internal thread hole of the insulating tie rod (203) through a stud.

5. The vacuum circuit breaker according to claim 4, wherein The outer cylindrical surface of the wheel-shaped contact (204) is provided with a U-shaped groove and a rectangular groove. A spring contact (206) is installed in the U-shaped groove, and a guide ring (207) is installed in the rectangular groove. The spring contact (206) is in sliding contact with the inner wall of the upper outlet conductor (202).

6. The vacuum circuit breaker according to claim 1, characterized in that, The bottom cover (3) is an outwardly convex casting structure, and there are casting bosses on the inner wall. The static-side insulating supports (210) of the three-phase phase columns (2) are fixed to the bosses by bolts.

7. The vacuum circuit breaker according to claim 1, characterized in that, A direct-acting sealing structure is provided between the transmission rod and the top cover (4), and the spring assembly (503) is in a pre-compressed state to ensure the synchronism of the opening and closing actions.

8. The vacuum circuit breaker according to claim 1, characterized in that, The layout forms of the outlet conductors include Z-shaped, U-shaped, T-shaped, or double-outlet type, which are achieved by adjusting the installation forms of the phase column conductors.

9. The vacuum circuit breaker according to claim 1, wherein, The static end of the vacuum interrupter (208) is fixed to the lower outlet conductor (209) by bolts, and the right end of the lower outlet conductor (209) is connected to the right-side outlet conductor.

10. The vacuum circuit breaker according to claim 1, characterized in that, The output shaft (601) of the operating mechanism (6) drives the transmission shaft (501) to move directly through the connecting rod (502), and drives the triangular bracket (504) to synchronously control the opening and closing of the three-phase phase columns.

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