A large-capacity vacuum interrupter and working method

Abstract

The application belongs to the technical field of vacuum arc-extinguishing chambers, and particularly relates to a large-capacity vacuum arc-extinguishing chamber and a working method. The large-capacity vacuum arc-extinguishing chamber comprises a vacuum insulation shell, a contact system arranged in the vacuum insulation shell, a rated current through-flow branch and an arc current through-flow branch arranged in parallel, a dynamic main contact and a static main contact matched with each other, a part of the static main contact penetrating through the vacuum insulation shell and exposed to an external environment to form a heat dissipation structure, an arc current through-flow branch comprising an inner arc contact, an outer arc contact and a magnetic field assembly electrically connected with the inner arc contact and the outer arc contact and used for generating a magnetic field for controlling an arc during opening and closing, and a conductive rod arranged at the upper and lower ends of the vacuum insulation shell and electrically connected with the contact system. The large-capacity vacuum arc-extinguishing chamber can meet the requirements of high rated current, large breaking current, high efficient heat dissipation and high voltage insulation, and overcomes the defects of mutual restriction of multiple performances in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of vacuum interrupter technology, specifically relating to a large-capacity vacuum interrupter and its operating method. Background Technology

[0002] Vacuum circuit breakers have undergone rapid development and are now widely used in power transmission and distribution. Their core component, the vacuum interrupter, has evolved from early flat contacts to various magnetic field-controlled contact structures. As vacuum circuit breakers continue to advance towards higher voltage and larger capacity, especially in demanding applications such as generator protection circuit breakers, increasingly higher requirements are being placed on their rated current carrying capacity. However, higher rated voltages force larger interrupter sizes, further exacerbating the inherent weakness of poor heat dissipation in vacuum interrupters; while higher short-circuit current breaking capacity requires more complex contact structures, leading to increased resistance in the conductive circuit and consequently, increased heat generation. Currently, the closest existing technology to this invention is the longitudinal magnetic field contact structure commonly used in large-capacity vacuum interrupters. This structure mainly consists of a moving conductive rod, a bellows, an end shield, a moving end contact system, a main shield, a stationary end contact system, a stationary conductive rod, and a stationary end conductive block. The contact system includes contact plates and a magnetic field assembly. The current path of the prior art is as follows: the rated current and the short-circuit current both flow through a single loop of "moving conductive rod, contact system, stationary conductive rod, stationary end conductive block", the breaking arc burns directly on the surface of the contact piece, and the entire contact system is in a high vacuum environment.

[0003] The aforementioned structural design leads to several inherent defects, and these defects are interconnected through a causal relationship. First, to meet the high breaking current capacity, existing technologies must employ complex magnetic field components to generate a sufficient longitudinal magnetic field. However, these complex components significantly increase the resistance of the conductive circuit, causing a sharp increase in heat generation at rated current. Second, during short-circuit current interruption, the arc burns violently on the contact surface. After repeated interruptions, the surface smoothness and finish of the contact plates deteriorate severely, leading to increased contact resistance between the moving and stationary contacts. This not only hinders the flow of high rated current but also further exacerbates Joule heating, creating a vicious cycle of heating and ablation. Third, the entire contact system is in a vacuum environment. Since the vacuum medium cannot transfer heat through convection, the heat generated by the contacts can only be dissipated through limited solid conduction and radiation, resulting in extremely low heat dissipation efficiency and becoming a fundamental bottleneck restricting the improvement of rated current. In summary, existing large-capacity vacuum interrupters suffer from a fundamental contradiction between large rated current and large breaking current, and also face structural defects such as poor heat dissipation, making it difficult to meet the growing demand of power systems for high-voltage, large-capacity vacuum circuit breakers. Summary of the Invention

[0004] The purpose of this invention is to provide a large-capacity vacuum interrupter and its operating method to solve the technical problems in the prior art, such as the vicious cycle of current degradation and ablation caused by the functional coupling of contact plates, the heat dissipation bottleneck in the vacuum environment, the increased heat generation of complex magnetic field components, and the inability to simultaneously handle large rated current and large breaking current.

[0005] To achieve the above objectives, the present invention employs the following technical solution: In a first aspect, this application discloses a large-capacity vacuum interrupter, comprising: Vacuum-insulated housing; The contact system is housed within a vacuum-insulated housing, and the contact system includes a rated current current-carrying branch and an arc current-carrying branch connected in parallel. The rated current flow branch includes a moving main contact and a stationary main contact that cooperate with each other. A portion of the stationary main contact passes through the vacuum insulation shell and is exposed to the external environment to form a heat dissipation structure. The arc current flow branch includes an inner arc contact, an outer arc contact, and a magnetic field assembly. The magnetic field assembly is electrically connected to the inner arc contact and the outer arc contact and is used to generate a magnetic field to control the arc during the opening and closing process. The conductive rod is located at the upper and lower ends of the vacuum insulating shell and is electrically connected to the contact system.

[0006] Optionally, the portion of the stationary main contact exposed to the external environment constitutes a heat dissipation surface, and the heat dissipation surface is provided with heat dissipation fins or an interface for connecting an external heat dissipation device.

[0007] Optionally, it also includes a bellows, an end shield, and a middle shield. The bellows is connected to the conductive rod. The end shields are located at the upper and lower ends inside the vacuum insulating shell, and the middle shield is located in the middle of the vacuum insulating shell. The end shields and the middle shield are used to optimize the electric field distribution and absorb arc spray.

[0008] Optionally, the magnetic field component is connected in series with the inner arc contact and the outer arc contact respectively, so that the arc current during the opening and closing process flows through the magnetic field component.

[0009] Optionally, the conductive rods are disposed at the upper and lower ends of the vacuum insulating shell, and the upper conductive rod and / or the lower conductive rod are moving ends, which are used to increase the effective external insulation size between the breaks.

[0010] Optionally, the contact mating surfaces of the moving main contact and the stationary main contact are located inside the vacuum insulating shell, while the outer circular surface of the stationary main contact is exposed outside the vacuum insulating shell, so that the heat generated at the contact surfaces of the moving main contact and the stationary main contact is directly conducted to the external environment through the stationary main contact.

[0011] Optionally, the current flow path of the rated current-carrying branch is as follows: conductive rod, moving main contact, stationary main contact, moving main contact, and conductive rod.

[0012] Optionally, the current flow path of the arc current flow branch is as follows: conductive rod, moving main contact, magnetic field assembly, inner arc contact, outer arc contact, magnetic field assembly, moving main contact and conductive rod.

[0013] Optionally, the large-capacity vacuum interrupter is a symmetrical structure with the contact system as the axis of symmetry.

[0014] Secondly, this application discloses a method for operating a large-capacity vacuum interrupter as described in any one of the above claims, characterized by comprising the following coordinated action steps: During the opening process, the moving main contact and the stationary main contact of the rated current current-carrying branch separate first, and the inner arc contact and the outer arc contact of the arc current-carrying branch separate later. During the closing process, the inner arc contact and outer arc contact of the arc current flow branch close first, and the moving main contact and stationary main contact of the rated current flow branch close later. In the closed state, the rated current flows through the rated current current-carrying branch; during the opening and closing process, the arc current flows through the arc current-carrying branch, and the magnetic field component generates a magnetic field to control the arc.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The large-capacity vacuum interrupter disclosed in this application decouples the functions of large rated current and large breaking current by setting the rated current current-carrying branch and the arc current-carrying branch in parallel. The moving main contact and the stationary main contact are dedicated to carrying the rated current and do not need to be subjected to arc erosion, thus maintaining a smooth contact surface and stable contact resistance for a long time. This avoids the vicious cycle of current degradation and heat generation caused by repeated interruption in traditional structures. At the same time, a part of the stationary main contact is exposed outside the vacuum insulation shell to form a heat dissipation structure, which can directly conduct the heat generated by the contact surface of the main contact to the external environment, breaking through the heat dissipation bottleneck in the vacuum environment. In addition, the independently set magnetic field component in the arc current-carrying branch works with the inner and outer arc contacts to generate a magnetic field during the breaking process to control the arc. This allows for a more complex and efficient magnetic field design, and the arc contacts can be made of ablation-resistant materials, significantly improving the short-circuit current breaking capacity and electrical life. In summary, the structure disclosed in this application enables the vacuum interrupter to meet the requirements of high rated current, large breaking current, efficient heat dissipation, and high voltage insulation, overcoming the defects of multiple performance constraints in the prior art.

[0016] Furthermore, by setting heat dissipation fins or connecting interfaces to external heat dissipation devices on the part of the stationary main contact exposed to the external environment, the heat exchange area between the stationary main contact and the external environment can be significantly increased or an efficient external heat dissipation path can be established. This allows the heat generated by the internal contact surface to be quickly conducted out and dissipated into the environment, thereby breaking through the bottleneck of heat dissipation by radiation and limited conduction in a vacuum environment. This effectively reduces the operating temperature rise of the contact system, improves the rated current carrying capacity of the vacuum interrupter, and provides thermal management assurance to meet the insulation requirements under higher voltage levels. Attached Figure Description

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

[0018] Figure 1 This is a schematic diagram of the structure of a dual-action, dual-circuit vacuum interrupter according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the contact system structure according to an embodiment of the present invention; Figure 3 This is a current path diagram of the closing state according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the arc current path during the closing and opening process of an embodiment of the present invention.

[0019] The components include: 1. Conductive rod; 2. Corrugated pipe; 3. End shield; 4. Ceramic shell; 5. Middle shield; 6. Contact system; 61. Moving main contact; 62. Magnetic field assembly; 63. Inner arc contact; 64. Stationary main contact; 65. Outer arc contact; 301. Rated current path in the closed state; 302. Main contact surface; 303. Arc current path during opening and closing; 304. Arc ablation during opening and closing; 305. Splashing of arc vapor particles and molten metal droplets. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of the embodiments of the present invention, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing the present 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, and therefore should not be construed as a limitation of the present invention. Furthermore, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0025] In the description of the embodiments of the present invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0026] The present invention will now be described in further detail with reference to the accompanying drawings: Vacuum switch: An electrical switching device that uses "vacuum" as an arc-extinguishing and insulating medium. It is mainly used in power systems to safely connect, carry, and disconnect current under normal conditions, and can connect, carry, and disconnect current for a certain time under specified abnormal conditions (such as short circuits).

[0027] Vacuum interrupter: also known as vacuum bubble, is the core component of vacuum switches (such as vacuum circuit breakers and vacuum contactors). It is a sealed cavity that uses a high vacuum as an insulating and arc-extinguishing medium to extinguish electric arcs and connect and disconnect current.

[0028] Vacuum contacts: Vacuum contacts are the core conductive components inside a vacuum interrupter. Specifically, they refer to the moving and stationary contacts that perform the functions of connecting, carrying, and disconnecting circuits in a vacuum environment.

[0029] Main contacts: The main contacts are the core conductive contact components in the vacuum interrupter, responsible for connecting and disconnecting the main circuit. They are directly responsible for carrying the normal operating current of the load and, in the event of a short circuit, work with the arc-extinguishing system to disconnect the short-circuit current.

[0030] Arc contact: An arc contact is an auxiliary contact specifically designed to withstand and guide an electric arc when breaking a circuit in a vacuum interrupter, in order to protect the main contacts from arc erosion.

[0031] See Figure 1 This application discloses a large-capacity vacuum interrupter, comprising: Vacuum-insulated housing; Contact system 6 is disposed inside a vacuum insulating shell. The contact system 6 includes a rated current current-carrying branch and an arc current-carrying branch arranged in parallel. The rated current flow branch includes a moving main contact 61 and a stationary main contact 64 that cooperate with each other. A portion of the stationary main contact 64 passes through the vacuum insulation shell and is exposed to the external environment, forming a heat dissipation structure. The arc current flow branch includes an inner arc contact 63, an outer arc contact 65, and a magnetic field assembly 62. The magnetic field assembly 62 is electrically connected to the inner arc contact 63 and the outer arc contact 65 and is used to generate a magnetic field to control the arc during the opening and closing process. Conductive rod 1 is installed at the upper and lower ends of the vacuum insulating shell and is electrically connected to the contact system 6.

[0032] In some embodiments, the portion of the stationary main contact 64 exposed to the external environment constitutes a heat dissipation surface, and this surface is provided with heat dissipation fins or an interface for connecting an external heat dissipation device. By directly providing heat dissipation fins or an interface for connecting an external heat dissipation device outside the stationary main contact 64, the heat generated by the main contact contact surface 302 can be transferred to the external environment via the shortest thermal path and dissipated efficiently, significantly improving the actual heat dissipation capacity of the heat source inside the vacuum interrupter. This not only overcomes the inherent bottleneck of difficult convective heat transfer in a vacuum environment and effectively reduces contact temperature rise, but also provides a reliable structural basis for meeting the requirements of higher rated current levels, while avoiding insulation degradation and reduced electrical life due to excessive temperature rise.

[0033] In some embodiments, the system further includes a bellows 2, an end shield 3, and a middle shield 5. The bellows 2 is connected to the conductive rod 1. The end shield 3 is located at the upper and lower ends inside the vacuum insulating shell, and the middle shield 5 is located in the middle of the vacuum insulating shell. The end shield 3 and the middle shield 5 are used to optimize the electric field distribution and absorb arc spray. By connecting the bellows 2 to the conductive rod 1, reliable sealing and reciprocating motion of the moving end are ensured. At the same time, the end shield 3 and the middle shield 5 work together to optimize the electric field distribution inside the vacuum interrupter, avoiding local field concentration that could lead to discharge. They also effectively absorb and condense the arc spray and metal vapor generated during the interruption process, preventing them from depositing on the inner wall of the insulating shell and reducing insulation performance. This significantly improves the insulation reliability and post-arc dielectric recovery capability of the vacuum interrupter under high voltage and high current interruption conditions, providing a guarantee for the long-term stable operation of the interrupter.

[0034] In some embodiments, the magnetic field component 62 is connected in series with the inner arc contact 63 and the outer arc contact 65, respectively, so that the arc current during the opening and closing process flows through the magnetic field component 62. By connecting the magnetic field component 62 in series with the inner arc contact 63 and the outer arc contact 65, it is ensured that the arc current during the opening and closing process will necessarily flow through the magnetic field component 62, thereby effectively controlling and guiding the arc using the magnetic field generated by the arc current itself. This series design eliminates the need for the magnetic field component 62 to rely on an independent current path, resulting in a more compact and reliable structure. Simultaneously, the arc is driven to rotate or diffuse under the influence of the magnetic field, reducing the arc energy density on the contact surface, mitigating the degree of arc contact erosion, and significantly improving the short-circuit current breaking capacity and electrical life. Furthermore, the magnetic field component 62 is decoupled from the main current-carrying branch, avoiding adverse effects on the rated current flow caused by the complex magnetic field structure.

[0035] In some embodiments, the conductive rod 1 is disposed at the upper and lower ends of the vacuum insulating shell, and the upper conductive rod 1 and / or the lower conductive rod 1 are moving ends, used to increase the effective external insulation size between the breaks. By disposing the conductive rods 1 at the upper and lower ends of the vacuum insulating shell, and making the upper and / or lower conductive rods 1 movable ends that can move relative to each other, the two ends can move relative to each other in opposite or the same direction during the opening process, thereby significantly increasing the total opening distance between the moving and stationary contacts and expanding the effective external insulation size. Compared with the single-end moving structure, the double-end moving structure can obtain a larger insulation gap at the same arc-extinguishing chamber height, improve the withstand voltage between the breaks, and better meet the external insulation requirements of high voltage levels; at the same time, the double-end moving structure can also balance the insulation voltage distribution, reduce local field strength concentration, and enhance the operational reliability of the vacuum arc-extinguishing chamber under high voltage conditions.

[0036] In some embodiments, the contact surfaces of the moving main contact 61 and the stationary main contact 64 are located inside the vacuum insulating shell, while the outer surface of the stationary main contact 64 is exposed outside the vacuum insulating shell. This allows the heat generated at the contact surface between the moving main contact 61 and the stationary main contact 64 to be directly conducted to the external environment through the stationary main contact 64. This establishes the shortest heat conduction path between the main heat source—the contact surface—and the external heat dissipation surface. Heat is directly transferred to the outer surface and dissipated into the environment via solid-state conduction through the stationary main contact 64 body, avoiding the lengthy path of indirect heat conduction through multiple components in traditional structures. This significantly reduces thermal resistance and greatly improves heat dissipation efficiency. This effectively overcomes the fundamental bottleneck of lacking a convective heat dissipation medium in a vacuum environment, suppresses the temperature rise of the contact system 6, ensures long-term stable current carrying capacity under high rated current, and lays the foundation for improving the overall reliability and lifespan of the vacuum interrupter.

[0037] In some embodiments, the current flow path of the rated current-carrying branch is as follows: conductive rod 1, moving main contact 61, stationary main contact 64, moving main contact 61, and conductive rod 1. When the circuit is closed, the rated current flows through a dedicated branch composed of the simple structure and low resistance of the moving main contact 61 and stationary main contact 64. The current path is short and does not require passing through the complex magnetic field component 62 or the arc contact, thus significantly reducing the resistance and Joule heating of the current-carrying circuit. Simultaneously, since this branch does not participate in arc interruption, the contact surfaces of the moving main contact 61 and stationary main contact 64 remain smooth and the contact resistance is stable. This avoids the vicious cycle of current-carrying capacity deterioration caused by repeated arc erosion in traditional structures, providing a reliable guarantee for the long-term stable bearing of large rated currents.

[0038] In some embodiments, the current flow path of the arc current carrying branch is as follows: conductive rod 1, moving main contact 61, magnetic field assembly 62, inner arc contact 63, outer arc contact 65, magnetic field assembly 62, moving main contact 61, and conductive rod 1. During the breaking process, the arc current is forcibly introduced into a dedicated branch formed by the series-connected magnetic field assembly 62, inner arc contact 63, and outer arc contact 65. On one hand, when the arc current flows through the magnetic field assembly 62, a strong longitudinal magnetic field is generated, effectively controlling the spread and rotation of the arc, reducing the arc energy density on the surface of the arc contact, and mitigating ablation. On the other hand, the inner arc contact 63 and outer arc contact 65 are made of ablation-resistant materials specifically designed to handle arc combustion and extinguishing, thus completely decoupling them from the current-carrying function of the main contact. This path allows the magnetic field design and contact material selection to be optimized independently, no longer constrained by the rated current, significantly improving the short-circuit current breaking capacity and electrical life.

[0039] In some embodiments, the high-capacity vacuum interrupter is a symmetrical structure with the contact system 6 as the axis of symmetry. This makes the electric field distribution on both sides of the interrupter more uniform and symmetrical, effectively avoiding the risk of insulation breakdown caused by local field strength concentration, and significantly improving the withstand voltage and insulation reliability between the breaks. Simultaneously, the symmetrical structure allows for better balance between the moving and stationary ends in terms of mechanical movement and thermal expansion, reducing eccentric torque and vibration caused by structural asymmetry, and improving the operational stability and mechanical life of the interrupter. Furthermore, the symmetrical design simplifies manufacturing and assembly processes, facilitates the implementation of a double-moving structure where both ends are moving, thereby increasing the effective opening distance without increasing the axial dimension, meeting the external insulation requirements of higher voltage levels, and providing a good foundation for serialized designs.

[0040] This application also discloses a method for operating a large-capacity vacuum interrupter as described in any one of the above claims, comprising the following coordinated action steps: During the opening process, the moving main contact 61 and the stationary main contact 64 of the rated current current-carrying branch separate first, and the inner arc contact 63 and the outer arc contact 65 of the arc current-carrying branch separate later. During the closing process, the inner arc contact 63 and outer arc contact 65 of the arc current flow branch close first, and the moving main contact 61 and stationary main contact 64 of the rated current flow branch close later. In the closed state, the rated current flows through the rated current current-carrying branch; during the opening and closing process, the arc current flows through the arc current-carrying branch, and the magnetic field component 62 generates a magnetic field to control the arc. By coordinating the timing of the main contacts separating first and the arc contacts separating later during opening, and the arc contacts closing first and the main contacts closing later during closing, it is ensured that the arc burns only on the dedicated arc contacts and is controlled by the magnetic field generated by the magnetic field component 62. The main contacts, in the stable closed state, carry the rated current and do not participate in the arcing process. This timing design fundamentally avoids the arc erosion of the main contact surface, allowing the main contacts to maintain excellent current-carrying performance with low resistance and high thermal conductivity over a long period. Simultaneously, the arc contacts can be made of erosion-resistant materials specifically for arc extinguishing, thus synergistically achieving a balance between large rated current and large breaking current, significantly improving the electrical life and operational reliability of the vacuum interrupter.

[0041] Example This embodiment provides a novel vacuum interrupter structure that resolves the contradiction between high rated current and high breaking current through a dual-circuit current-shunting design. It also separates the traditional contact plates from their function of carrying rated current while withstanding arc erosion, improving the current-carrying capacity of existing vacuum interrupter contact surfaces after repeated arc erosion. The dual-action structure design addresses the heat dissipation bottleneck and meets the high-voltage external insulation requirements of vacuum interrupters. The structure includes the following components: Conductive rod 1, through which the vacuum interrupter is electrically connected to the outside; Bellows 2, through its expansion and contraction, enables the relative movement of the electrodes in the vacuum interrupter; The end shield 3, together with the middle shield 5, constitutes a shield system to optimize the electric field inside the vacuum interrupter and absorb particle sputtering generated by the vacuum arc. The ceramic shell 4 forms part of the vacuum-sealed environment of the vacuum interrupter and also meets the insulation requirements at both ends of the vacuum interrupter. The middle shield 5, together with the end shield 3, constitutes a shield system that optimizes the electric field inside the vacuum interrupter and absorbs particle sputtering generated by the vacuum arc. Contact system 6 conducts rated current, interrupts short-circuit current, and extinguishes the arc. See also Figure 2 ,include: The moving main contact 61 moves with the conductive rod 1 and together with the stationary main contact 64, constitutes the main contact system. In the closed state of the vacuum interrupter, it serves as the main path for current flow. Due to its simple structure, it generates less heat. The magnetic field component 62 generates a magnetic field to assist in arc control and extinguishing during the closing and opening of the circuit breaker, through which the arc current flows. The inner arc contact 63, together with the outer arc contact 65, constitutes the arc contact system. These can be made of materials with slightly lower current-carrying capacity but better ability to suppress field emission or resist ablation, such as copper-tungsten alloys. During the closing and opening process, the electric arc ablates and extinguishes on these materials. The stationary main contact 64, together with the moving main contact 61, constitutes the main contact system. It serves as the main path for current flow when the vacuum interrupter is closed. Due to its simple structure, it generates less heat. In addition, as part of the housing assembly, the stationary main contact 64 has its upper and lower surfaces used to contact the moving contact to form a conductive path. Its outer circular surface is located outside the vacuum environment and is a heat dissipation surface outside the vacuum interrupter, thereby significantly improving the heat dissipation effect of the heat source. The outer arc contact 65, together with the inner arc contact 63, constitutes the arc contact system. These can be made of materials with slightly lower current-carrying capacity but better ability to suppress field emission or resist ablation, such as copper-tungsten alloys. During the closing and opening process, the electric arc ablates and extinguishes on these materials. The dual-circuit contact system 6 is adopted: the main current-carrying branch (main contact) provides stable current flow in the closed state, meeting the requirements of large rated current; the arc current-carrying branch (arc contact and magnetic field assembly 62) controls the arc during the closing and opening process, meeting the requirements of large breaking capacity.

[0042] The dual-moving structure is adopted: the stationary main contact 64 is part of the housing assembly, and its upper and lower surfaces are in contact with the moving main contact 61 for conduction. Its outer circular surface is placed outside the vacuum environment as a heat dissipation surface, which significantly improves the heat dissipation effect of the heat source.

[0043] Coordination of actions: When opening, the main contacts open first, followed by the arc contacts; when closing, the arc contacts close first, followed by the main contacts.

[0044] The current shunt design of contact system 6 allows large rated currents to flow through the main current-carrying branch, resulting in a simple structure, short path, low heat generation, and good heat dissipation. Large short-circuit currents and arc currents flow through the arc current-carrying branch, which features a specially designed magnetic field generator and arc contacts. This design makes the magnetic field more effective in controlling the arc, and the arc contacts are easy to extinguish and resistant to ablation. When designing the current shunt of contact system 6, special attention must be paid to the coordination of the opening and closing sequence of the two branches. This ensures that when opening, the main contacts open first, followed by the arc contacts; and when closing, the arc contacts close first, followed by the main contacts. Simultaneously, it must meet the insulation requirements for the main arc contact opening distance and the operating speed requirements.

[0045] A portion of the stationary main contact 64 is located outside the vacuum interrupter for heat dissipation. A key aspect is the design of the inner surface of the stationary main contact 64 as part of the main shielding function, satisfying insulation optimization and arc particle absorption requirements. The outer surface of the stationary main contact 64 serves as a critical heat dissipation component, effectively utilizing its structure to enhance heat dissipation and increase rated current. Simultaneously, as the primary load-bearing component for closing and opening operations, the stationary main contact 64 must be reliably fixed. During fixing, an insulation structure to ground must be considered, and the operating force must not be transmitted to other sealing components to ensure the vacuum environment's sealing performance.

[0046] Current path design (e.g.) Figure 3 , Figure 4 ): Rated current path 301 in closed state: Conductive rod 1, moving main contact 61, stationary main contact 64, moving main contact 61 and conductive rod 1; Arc current path 303 during opening and closing: Conductive rod 1, moving main contact 61, magnetic field assembly 62, inner arc contact 63, outer arc contact 65, magnetic field assembly 62, moving main contact 61 and conductive rod 1.

[0047] The current path design in this application resolves the conflict between large rated current and large breaking current: Regarding rated current carrying capacity, traditional single-circuit contact plates bear both current carrying capacity and arc erosion. After repeated interruptions, the surface smoothness and finish deteriorate, leading to increased contact resistance and consequently affecting the rated current carrying capacity. In contrast, the dual-circuit structure of this invention separates functions. The main contact is dedicated solely to rated current carrying and does not undertake arc extinguishing, thus avoiding arc erosion damage and maintaining a smooth surface finish over time. The main contact structure is simple and generates low heat, fundamentally ensuring a long-term stable rated current carrying capacity.

[0048] In terms of short-circuit current interruption, the magnetic field component 62 in the traditional structure needs to simultaneously handle current flow and magnetic field generation, which severely restricts design space and makes it difficult to optimize both performance aspects at the same time. In the dual-loop structure of this invention, the magnetic field component 62 is dedicated to magnetic field generation, allowing for more complex designs to produce a stronger magnetic field control effect without considering current flow heating limitations; the arc contact is made of ablation-resistant materials such as copper-tungsten alloy, specifically tasked with handling arc ablation during opening and closing. This division of labor results in stronger magnetic field control, faster arc extinguishing, better ablation resistance of the arc contact, and a significant improvement in overall breaking capacity and service life.

[0049] In terms of overall performance, the high rated current and high breaking current performance in traditional single-loop structures are mutually restrictive, exhibiting an inverse relationship and making it difficult to improve them simultaneously. This invention, through a decoupled dual-loop design, enables independent optimization and simultaneous improvement of these two performance characteristics, ultimately achieving the dual high-parameter target of "high rated current + high breaking current," breaking through the technical bottleneck of existing technologies.

[0050] Features of a double-movement structure: As part of the housing assembly, the static main contact 64 achieves the dual functions of "internal conductivity and external heat dissipation", enabling the theoretically shortest path from the heat source to the heat dissipation point. Both ends of the vacuum interrupter are movable ends (one end of each of the upper and lower conductive rods can be designed as a movable end), increasing the effective external insulation dimension between the breaks. The symmetrical structure ensures that the insulation dimensions at both ends bear the insulation voltage between the breaks equally.

[0051] This application employs a dual-action structural feature, resolving the contradiction between heat dissipation bottleneck and high-voltage insulation: Significantly improved heat dissipation capacity The outer circular surface of the stationary main contact 64 is placed outside the vacuum environment, forming a strong heat dissipation surface and creating conditions for the addition of other forced heat dissipation structures. The strong heat source (main contact surface 302) and the strong heat dissipation surface (outer surface of stationary main contact 64) are located on two sides of the same part. Heat can be directly conducted to the external environment through the stationary main contact 64, breaking through the heat dissipation bottleneck in the vacuum environment. The arc particle condensation and adsorption capacity is enhanced. As part of the housing assembly, the temperature of the stationary main contact 64 can be effectively reduced through external heat dissipation. The low-temperature surface enhancement enhances the condensation and adsorption capacity of arc vapor particles and metal droplets 305 generated when interrupting short-circuit current, thereby improving the insulation recovery speed inside the vacuum interrupter.

[0052] The high-voltage insulation capability is enhanced, and the double-moving structure makes both ends of the vacuum interrupter moving, increasing the effective external insulation size between the breaks. The symmetrical structure ensures that the insulation size at both ends bears the insulation voltage requirement between the breaks on an average basis, making it easier to meet the insulation parameter requirements between breaks under high voltage levels.

[0053] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A large-capacity vacuum interrupter, characterized in that, include: Vacuum-insulated housing; The contact system (6) is disposed inside a vacuum insulating shell. The contact system (6) includes a rated current current-carrying branch and an arc current-carrying branch arranged in parallel. The rated current flow branch includes a moving main contact (61) and a stationary main contact (64) that cooperate with each other. The upper and lower surfaces of the stationary main contact (64) are in contact with the moving main contact (61) and conduct electricity. The stationary main contact (64) is hollow inside. The arc current flow branch includes an inner arc contact (63), an outer arc contact (65), and a magnetic field assembly (62). The moving main contact (61) is connected to the magnetic field assembly (62). The magnetic field assembly (62) passes through the upper and lower surfaces of the stationary main contact (64) and is connected in series with the inner arc contact (63) and the outer arc contact (65). The inner arc contact (63) and the outer arc contact (65) are located inside the stationary main contact (64) and are used to generate a magnetic field to control the arc during the opening and closing process. The conductive rod (1) is set at the upper and lower ends of the vacuum insulating shell and electrically connected to the contact system (6); The contact mating surfaces of the moving main contact (61) and the stationary main contact (64) are located inside the vacuum insulation shell, while the outer circular surface of the stationary main contact (64) is exposed outside the vacuum insulation shell, so that the heat generated by the contact surfaces of the moving main contact (61) and the stationary main contact (64) is directly conducted to the external environment through the stationary main contact (64). The portion of the stationary main contact (64) exposed to the external environment constitutes a heat dissipation surface, and the heat dissipation surface is provided with heat dissipation fins or an interface for connecting an external heat dissipation device. It also includes a bellows (2), an end shield (3) and a middle shield (5). The bellows (2) is connected to the conductive rod (1). The end shield (3) is set at the upper and lower ends inside the vacuum insulating shell. The middle shield (5) is set in the middle of the vacuum insulating shell. The end shield (3) and the middle shield (5) are used to optimize the electric field distribution and absorb arc spray.

2. The large-capacity vacuum interrupter according to claim 1, characterized in that, The conductive rod (1) is set at the upper and lower ends of the vacuum insulating shell, and the upper conductive rod (1) and / or the lower conductive rod (1) are moving ends, which are used to increase the effective external insulation size between the breaks.

3. A large-capacity vacuum interrupter according to claim 1, characterized in that, The current flow path of the rated current current-carrying branch is as follows: conductive rod (1), moving main contact (61), stationary main contact (64), moving main contact (61) and conductive rod (1).

4. A large-capacity vacuum interrupter according to claim 1, characterized in that, The current flow path of the arc current flow branch is as follows: conductive rod (1), moving main contact (61), magnetic field assembly (62), inner arc contact (63), outer arc contact (65), magnetic field assembly (62), moving main contact (61) and conductive rod (1).

5. A large-capacity vacuum interrupter according to claim 1, characterized in that, The large-capacity vacuum interrupter is a symmetrical structure with the contact system (6) as the axis of symmetry.

6. A method for operating a large-capacity vacuum interrupter as described in any one of claims 1 to 5, characterized in that, Includes the following action coordination steps: During the opening process, the moving main contact (61) and the stationary main contact (64) of the rated current current-carrying branch separate first, and the inner arc contact (63) and the outer arc contact (65) of the arc current-carrying branch separate later. During the closing process, the inner arc contact (63) and outer arc contact (65) of the arc current flow branch close first, and the moving main contact (61) and stationary main contact (64) of the rated current flow branch close later. In the closed state, the rated current flows through the rated current current-carrying branch; during the opening and closing process, the arc current flows through the arc current-carrying branch, and the magnetic field component (62) generates a magnetic field to control the arc.

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