Vacuum arc-extinguishing chamber contact structure and method

Abstract

In the vacuum arc-extinguishing chamber contact structure, a contact support is conductively and coaxially connected to the end portion of a conducting rod so as to support a first contact blade and a second contact blade, the first contact blade is coaxially connected with the contact support, the first contact blade is of a hollow annular structure, and the second contact blade is of a hollow annular structure. At least one annular cutting groove and at least one radial cutting groove are formed in the annular structure so as to segment the vacuum arc and hinder the radial movement and the annular movement of the arc column, the second contact blade is coaxially connected with the contact support and located in the center of the first contact blade, and the second contact blade is made of an arc ablation resistant material. The structure adopts a lightweight design, greatly reduces the mass of the contact, has the advantages of strong arc control capability, fast breaking speed, high mechanical strength, small steady-state heating and the like, and can meet the application requirements of large-current vacuum rapid breaking.

Description

Technical Field

[0001] The invention relates to the technical field of vacuum interrupter chambers, and in particular to a vacuum interrupter chamber contact structure and method. Background Art

[0002] As a key power switchgear, large-capacity circuit breakers are of great significance to maintaining the safe and stable operation of power systems. 6 Breaking principle, SF 6 Gas is not environmentally friendly and is not conducive to the development of environmentally friendly power equipment. Vacuum circuit breakers use the vacuum arc extinguishing principle, which is completely environmentally friendly and is the key to achieving SF 6 The preferred option for environmentally friendly alternatives.

[0003] The vacuum interrupter is the core component of the vacuum circuit breaker. Applying a longitudinal magnetic field in the contact gap can effectively control the shape of the vacuum arc and improve the ability to interrupt short-circuit current. There are various ways to generate a longitudinal magnetic field. The most widely used method is to design a cup-shaped contact structure. When the current flows through the inclined slot opened by the contact cup, a longitudinal magnetic field will be generated in the contact gap.

[0004] The traditional cup-shaped longitudinal magnetic contact has a large moving mass and a long current path, which results in significant problems such as slow breaking speed, low mechanical life, and high steady-state temperature rise, making it difficult to meet the actual needs of high-current rapid breaking. Therefore, how to coordinately optimize the "temperature rise-movement-breaking" characteristics of the vacuum interrupter has become a key issue that needs to be solved in this field.

[0005] The information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0006] In view of the shortcomings or defects of the above-mentioned prior art, a vacuum arc extinguishing chamber contact structure and method are provided, which adopt a lightweight design, can delay the generation of the central concentrated arc and slow down the ablation of the central concentrated arc. When a rapid operating mechanism is used to drive the movement of the contact, it has the significant advantages of strong arc control ability, fast breaking speed, low steady-state temperature rise, and long mechanical life. It can greatly improve the reliability of short-circuit current breaking and better meet the application requirements of large current fast breaking.

[0007] The purpose of the present invention is achieved through the following technical solutions.

[0008] A vacuum interrupter contact structure includes:

[0009] Conductive rod,

[0010] A contact support is coaxially connected to the end of the conductive rod to support the first contact piece and the second contact piece.

[0011] The first contact piece is coaxially connected to the contact support, and the first contact piece is a hollow annular structure, and the annular structure is provided with at least one annular groove and at least one radial groove to divide the vacuum arc and hinder the radial movement and annular movement of the arc column.

[0012] The second contact piece is coaxially connected to the contact support and is located at the center of the first contact piece. The second contact piece is made of arc erosion resistant material.

[0013] The vacuum interrupter contact structure is characterized in that the diameter of the first contact piece is the same as the diameter of the contact support and is larger than the diameter of the conductive rod, and the diameter of the second contact piece is smaller than the diameter of the first contact piece.

[0014] In the vacuum interrupter contact structure, the first contact piece is a circular ring structure, and the second contact piece is a disc structure.

[0015] In the vacuum interrupter contact structure, the first contact piece includes a plurality of radial grooves, and the plurality of radial grooves are centrally symmetrical with respect to the center of the first contact piece.

[0016] In the vacuum interrupter contact structure, the first contact piece includes a plurality of annular grooves, and the centers of the annular grooves coincide with the center of the first contact piece.

[0017] In the vacuum interrupter contact structure, the arc erosion resistant material includes copper-tungsten alloy, copper-tungsten-tungsten carbide alloy or copper-chromium alloy.

[0018] In the vacuum interrupter contact structure, the height of the second contact piece is the same as the remaining height of the first contact piece after the groove is formed.

[0019] In the vacuum interrupter contact structure, the vacuum interrupter contact structure and the longitudinal magnetic contact together constitute an asymmetric contact system, wherein the vacuum interrupter contact structure serves as a moving contact, the longitudinal magnetic contact serves as a static contact, and a rapid operating mechanism is used to drive the contact movement, and the rapid operating mechanism includes an electromagnetic repulsion mechanism, a hydraulic spring mechanism or a high-speed motor mechanism.

[0020] In the vacuum interrupter contact structure, the longitudinal magnetic contact includes a cup-shaped longitudinal magnetic contact, a coil-type longitudinal magnetic contact or a permanent magnet contact structure.

[0021] The breaking methods of the vacuum interrupter contact structure include:

[0022] The vacuum interrupter contact structure and the longitudinal magnetic contact together form an asymmetric contact system. As the contacts separate, multiple parallel vacuum arcs are simultaneously generated in the gap between the first contact piece and the longitudinal magnetic contact.

[0023] As the contact opening distance increases, the arc column of the vacuum arc is elongated. Under the action of the electromagnetic field in space, each segment of the vacuum arc gradually converges toward the center of the contact. The groove of the first contact piece not only distributes the arc energy to multiple arc columns, but also hinders the movement of the arc column, delaying the appearance time of the central concentrated arc, which helps to reduce the amount of contact ablation.

[0024] Multiple vacuum arcs converge to the center of the second contact piece to form a concentrated arc. The second contact piece is made of ablative materials, which reduces the degree of ablation of the contact by the concentrated arc, alleviates the splashing of metal droplets, reduces the amount of arc plasma, and improves the dielectric recovery ability after the arc.

[0025] The transfer branch injects reverse current into the asymmetric contact system according to a specific timing. The contact current drops to the current zero point. The asymmetric contact system withstands the transient recovery voltage and finally completes the current interruption.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The annular groove and radial groove of the first contact piece of the present invention can effectively divide the arc, improve the contact surface utilization rate, and hinder the convergence of multiple arc columns to the center, delaying the appearance of the center-concentrated arc. The second contact piece adopts an alloy material with higher hardness and better arc erosion resistance, which can reduce the degree of ablation of the contact material by the concentrated arc and reduce the splashing of metal droplets. The functions of the two contact pieces are conducive to enhancing the ability of the circuit breaker to recover the dielectric after the arc, and improving the reliability of large-capacity breaking.

[0028] (2) Compared with the traditional cup-shaped longitudinal magnetic contact, the proposed contact structure has a shorter current path, a smaller contact resistance in the closed state, and a greater current capacity.

[0029] (3) The proposed contact structure adopts a lightweight design with small moving parts and high mechanical strength, which is conducive to rapid breaking of large currents and has a long mechanical life.

[0030] Specific functions of each component:

[0031] Conductive rod

[0032] Technical function: As the main current conduction path, it is responsible for transmitting current from the external circuit to the contact system.

[0033] Synergy: Coaxially connected with the contact support to ensure smooth transmission of current to the contact system and provide sufficient mechanical support when the contacts are separated.

[0034] Contact support

[0035] Technical function: As an intermediate connector, it coaxially connects the conductive rod with the first contact piece and the second contact piece to provide structural support and ensure uniform distribution of current.

[0036] Synergy: The contact holder not only provides a mechanical connection, but also ensures a smooth transition of current from the conductive rod to the first and second contact pieces. Its coaxial design helps to evenly distribute the current and avoid local overheating or current concentration.

[0037] First contact piece

[0038] Technical role:

[0039] Hollow ring structure: has a larger surface area, helps to reduce contact resistance and can better distribute arc energy.

[0040] Circumferential and radial grooves: These grooves divide the first contact piece into multiple small areas, which helps to divide the vacuum arc, hinder the radial and circumferential movement of the arc column, and delay the formation time of the central concentrated arc.

[0041] Multi-section parallel arc generation: As the contacts separate, the first contact piece can generate parallel vacuum arcs at multiple locations simultaneously, dispersing the arc energy and reducing single-point ablation.

[0042] Synergistic effect: The slot design of the first contact piece makes the arc energy evenly distributed in multiple small areas, reducing the arc intensity in a single area, thereby reducing the degree of ablation on the contact surface. In addition, the design of annular and radial slots helps to delay the formation of central concentrated arcs, further reducing the amount of ablation on the contact.

[0043] Second contact piece

[0044] Technical role:

[0045] Disc-shaped structure: Located in the center of the first contact piece, it is made of materials with good arc erosion resistance (such as copper-tungsten alloy, copper-tungsten carbide alloy or copper-chromium alloy), and can withstand higher temperatures and arc impacts when the arc converges.

[0046] Reduce ablation and splashing of metal droplets: Due to its material properties, the second contact piece can significantly reduce the ablation of the contact material by the concentrated arc, reduce the splashing of metal droplets, and improve the dielectric recovery ability after the arc.

[0047] Synergistic effect: The second contact piece is the final arc convergence point. Its material with good arc ablation resistance effectively reduces the damage of the concentrated arc to the contact material. Its height is the same as the remaining height of the first contact piece after the slot is opened, so that the current when the moving and static contacts are closed is only conducted through the first contact piece, which is conducive to the arc starting at multiple points on the first contact piece when the moving and static contacts are separated.

[0048] Collaborative work ensures technical results

[0049] Current conduction path optimization

[0050] The conductive rod, contact holder, first contact piece and second contact piece together form a complete current conduction path. The conductive rod introduces the current into the contact system, and the contact holder ensures that the current is evenly distributed to the first contact piece and the second contact piece. This design shortens the current path, reduces the contact resistance and steady-state temperature rise, and improves the current carrying capacity of the circuit breaker.

[0051] Arc energy dispersion and control

[0052] The circumferential and radial grooves of the first contact piece allow the arc energy to be dispersed in multiple small areas, avoiding high energy concentration at a single point. This not only reduces the ablation of the contact surface, but also extends the service life of the contact.

[0053] As the contact opening distance increases, the vacuum arcs gradually converge toward the center area. At this time, the slot design of the first contact piece hinders the arc movement, delays the formation of the center-aggregated arc, and further reduces the amount of contact ablation.

[0054] Arc erosion resistance and metal droplet control

[0055] The second contact piece is made of a material with good arc erosion resistance, which can withstand high temperature and high pressure when the arc converges, reducing the erosion of the contact material. In addition, its material properties can effectively reduce the splashing of metal droplets and improve the dielectric recovery ability after the arc.

[0056] Optimization of asymmetric contact systems

[0057] The lightweight large-capacity contact structure proposed in the present invention and the traditional cup-shaped longitudinal magnetic contact constitute an asymmetric contact system, in which the moving contact is the contact structure of the present invention and the static contact is the traditional cup-shaped longitudinal magnetic contact. This lightweight contact combination not only achieves fast opening, but also compensates for the influence of longitudinal magnetic field attenuation on arc control ability, significantly improving the reliability of the asymmetric contact system in high-current fast breaking.

[0058] Application of Current Transfer Circuit Breaker Topology

[0059] In practical applications, the combination of electromagnetic repulsion mechanism, hydraulic spring mechanism or high-speed motor mechanism and other fast operating mechanisms can achieve rapid breaking of large currents. By injecting reverse current through the transfer branch controlled by a specific timing sequence, the contact current is forced to drop rapidly to the current zero point. The contact system successfully withstands the transient recovery voltage and finally completes the breaking of large currents.

[0060] Summarize

[0061] The vacuum interrupter contact structure of the present invention realizes efficient current interruption and arc control through the coordinated work of the conductive rod, the contact support, the first contact piece and the second contact piece. Specifically, the slot design of the first contact piece disperses the arc energy and reduces contact ablation; the arc-resistant material of the second contact piece reduces the damage to the contact caused by the concentrated arc; the overall structure adopts a lightweight design, which not only optimizes the current path and improves the current carrying capacity, but also reduces the mass of the moving parts and improves the reliability of the circuit breaker's rapid breaking. These designs work together to ensure the efficient operation and long life of the contact structure under complex working conditions.

[0062] The above description is only an overview of the technical solution of the present invention. In order to make the technical means of the present invention clearer and to achieve the extent that those skilled in the art can implement it according to the contents of the specification, and in order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are exemplified below. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] By reading the detailed description of the preferred specific embodiments below, various other advantages and benefits of the present invention will become clear to those of ordinary skill in the art. The drawings in the specification are only for the purpose of illustrating the preferred embodiments and are not considered to be limitations of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative work. Moreover, the same reference numerals are used to represent the same components throughout the drawings.

[0064] In the attached picture:

[0065] Figure 1 It is a schematic diagram of a lightweight and large-capacity vacuum interrupter contact structure provided by an embodiment of the present invention;

[0066] Figure 2 (a) is a top view of a novel contact structure provided by an embodiment of the present invention;

[0067] Figure 2 (b) is a schematic diagram of a novel contact structure provided by an embodiment of the present invention generating a multi-segment vacuum arc;

[0068] Figure 2 (c) is a schematic diagram of the movement of multiple vacuum arcs toward the center in a novel contact structure provided by an embodiment of the present invention;

[0069] Figure 2 (d) is a schematic diagram of a novel contact structure provided by an embodiment of the present invention generating a concentrated arc at the center;

[0070] Figure 3 is a schematic diagram of an asymmetric contact system provided by another embodiment of the present invention;

[0071] Figure 4 is a schematic diagram of a current transfer fast breaking topology provided by another embodiment of the present invention;

[0072] Figure 5 (a) is a schematic diagram of the flow path of a conventional cup-shaped longitudinal magnetic contact system in a closed state provided by another embodiment of the present invention;

[0073] Figure 5 (b) is a schematic diagram of the flow path of the asymmetric contact system in a closed state provided by another embodiment of the present invention;

[0074] Figure 6 (a) is Figure 3 Schematic diagram of multi-point arc starting phase of the asymmetric contact system shown;

[0075] Figure 6 (b) is Figure 3 Schematic diagram of arc column movement phases of the asymmetric contact system shown;

[0076] Figure 6 (c) is Figure 3 Schematic diagram of the concentrated arc ablation stage of the asymmetric contact system shown;

[0077] Figure 6 (d) is Figure 3 Schematic diagram of the transfer and breaking phase of the asymmetric contact system shown.

[0078] The present invention is further explained below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0079] The specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0080] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the attached claims.

[0081] To facilitate understanding of the embodiments of the present invention, several specific embodiments will be further explained below with reference to the accompanying drawings, and each of the accompanying drawings does not constitute a limitation on the embodiments of the present invention.

[0082] For a better understanding, Figures 1 to 6 As shown, a vacuum interrupter contact structure includes:

[0083] Conductive rod 4,

[0084] The contact support 3 is coaxially connected to the end of the conductive rod 4 to support the first contact piece 1 and the second contact piece 2.

[0085] The first contact piece 1 is coaxially connected to the contact support 3. The first contact piece 1 is a hollow annular structure. The annular structure is provided with at least one annular groove and at least one radial groove to divide the vacuum arc and hinder the radial movement and annular movement of the arc column.

[0086] The second contact piece 2 is coaxially connected to the contact support 3 and is located at the center of the first contact piece 1. The second contact piece 2 is made of arc erosion resistant material.

[0087] In a preferred embodiment of the vacuum interrupter contact structure, the diameter of the first contact piece 1 is the same as the diameter of the contact support 3 and is larger than the diameter of the conductive rod 4 , and the diameter of the second contact piece 2 is smaller than the diameter of the first contact piece 1 .

[0088] In a preferred embodiment of the vacuum interrupter contact structure, the first contact piece 1 is a circular ring structure, and the second contact piece 2 is a disc structure.

[0089] In a preferred embodiment of the vacuum interrupter contact structure, the first contact piece 1 includes a plurality of radial grooves, and the plurality of radial grooves are centrally symmetrical with respect to the center of the first contact piece 1 .

[0090] In a preferred embodiment of the vacuum interrupter contact structure, the first contact piece 1 includes a plurality of annular grooves, and the centers of the annular grooves coincide with the center of the first contact piece 1 .

[0091] In a preferred embodiment of the vacuum interrupter contact structure, the arc erosion resistant material comprises copper-tungsten alloy, copper-tungsten-tungsten carbide alloy or copper-chromium alloy.

[0092] In a preferred embodiment of the vacuum interrupter contact structure, the height of the second contact piece 2 is the same as the remaining height of the first contact piece 1 after the grooves are formed.

[0093] In a preferred embodiment of the vacuum interrupter contact structure, the vacuum interrupter contact structure and the longitudinal magnetic contact together constitute an asymmetric contact system, wherein the vacuum interrupter contact structure serves as a moving contact, the longitudinal magnetic contact serves as a static contact, and a rapid operating mechanism is used to drive the contact movement, and the rapid operating mechanism includes an electromagnetic repulsion mechanism, a hydraulic spring mechanism or a high-speed motor mechanism.

[0094] In a preferred embodiment of the vacuum interrupter contact structure, the longitudinal magnetic contact includes a cup-shaped longitudinal magnetic contact, a coil-type longitudinal magnetic contact or a permanent magnet contact structure.

[0095] The breaking methods of the vacuum interrupter contact structure include:

[0096] The vacuum interrupter contact structure and the longitudinal magnetic contact together form an asymmetric contact system. As the contacts separate, multiple parallel vacuum arcs are simultaneously generated in the gap between the first contact piece 1 and the longitudinal magnetic contact.

[0097] As the contact opening distance increases, the arc column of the vacuum arc is elongated. Under the action of the electromagnetic field in space, each segment of the vacuum arc gradually converges toward the center of the contact. The groove of the first contact piece 1 not only distributes the arc energy to multiple arc columns, but also hinders the movement of the arc column, delaying the appearance time of the central concentrated arc, which helps to reduce the ablation amount of the contact.

[0098] Multiple vacuum arcs converge to the center of the second contact piece 2 to form a concentrated arc. The second contact piece is made of a material with strong ablation resistance, which reduces the degree of ablation of the contact by the concentrated arc, effectively alleviates the splashing of metal droplets, reduces the amount of arc plasma, and improves the dielectric recovery ability after the arc.

[0099] The transfer branch injects reverse current into the asymmetric contact system according to a specific timing. The contact current drops to the current zero point. The asymmetric contact system withstands the transient recovery voltage and finally completes the current interruption.

[0100] In one embodiment, a lightweight and high-capacity vacuum interrupter contact structure includes:

[0101] The first contact piece 1 is coaxially connected to the contact support 3. The first contact piece 1 is a hollow annular structure, which has at least one annular groove and one radial groove. The groove can divide the vacuum arc and hinder the radial and annular movement of the arc column, which helps to distribute the arc energy and delay the generation of center-concentrated arc.

[0102] The second contact piece 2 is coaxially connected to the contact support 3. The second contact piece 2 is made of a material with good arc erosion resistance. It is located at the center of the first contact piece 1, which can reduce the degree of erosion of the contact material by the concentrated arc and reduce the splashing of metal droplets.

[0103] The contact support 3 is coaxially connected to the conductive rod 4 and is used to support the first contact piece 1 and the second contact piece 2.

[0104] The conductive rod 4 is coaxially connected to the contact support 3 and is used for conducting large current.

[0105] In the preferred embodiment of the lightweight large-capacity vacuum interrupter contact structure, the diameter of the first contact piece 1 is the same as the diameter of the contact support 3 and is larger than the diameter of the conductive rod 4. The diameter of the second contact piece 2 is smaller than the diameter of the first contact piece 1.

[0106] In a preferred embodiment of the lightweight and large-capacity vacuum interrupter contact structure, the first contact piece 1 is a ring-shaped structure, and the second contact piece 2 is a disc-shaped structure.

[0107] In a preferred embodiment of the lightweight and large-capacity vacuum interrupter contact structure, the first contact piece 1 includes at least one radial groove, and the plurality of radial grooves are centrally symmetrical with respect to the center of the first contact piece 1 .

[0108] In a preferred embodiment of the lightweight and large-capacity vacuum interrupter contact structure, the first contact piece 1 includes at least one annular groove, and the center of the annular groove coincides with the center of the first contact piece 1.

[0109] In the preferred embodiment of the lightweight and large-capacity vacuum interrupter contact structure, the second contact piece 2 is made of a material with good arc erosion resistance, including copper-tungsten alloy, copper-tungsten-tungsten carbide alloy, and copper-chromium alloy.

[0110] In a preferred embodiment of the lightweight and large-capacity vacuum interrupter contact structure, the height of the second contact piece 2 is the same as the remaining height of the first contact piece 1 after the groove is formed.

[0111] In a preferred embodiment of the lightweight and large-capacity vacuum interrupter contact structure, the contact structure also includes an asymmetric contact system formed together with the longitudinal magnetic contact.

[0112] In a preferred embodiment of the lightweight and large-capacity vacuum interrupter contact structure, the longitudinal magnetic contact includes a cup-shaped longitudinal magnetic contact, a coil-type longitudinal magnetic contact, and a permanent magnet contact structure.

[0113] In the preferred embodiment of the lightweight and large-capacity vacuum interrupter contact structure, the asymmetric contact system has a lightweight and large-capacity contact as a moving contact and a longitudinal magnetic contact as a static contact. A rapid operating mechanism is used to drive the contact movement. The rapid operating mechanism includes an electromagnetic repulsion mechanism, a hydraulic spring mechanism, and a high-speed motor mechanism.

[0114] In one embodiment, a lightweight and large-capacity vacuum interrupter contact structure is shown, including a first contact piece 1, a second contact piece 2, a contact holder 3 and a conductive rod 4. The first contact piece 1 is a hollow annular structure, with radial grooves and annular grooves. The second contact piece 2 is a disc structure, and is made of alloy materials with good arc erosion resistance, including copper-chromium alloy, copper-tungsten alloy, and copper-tungsten-tungsten carbide alloy. The contact piece, the contact holder 3 and the conductive rod 4 are coaxially connected by vacuum welding, and the second contact piece 2 is located at the center of the first contact piece 1, and the height is the same as the remaining height of the first contact piece 1 after the groove is opened.

[0115] In the embodiment of the present invention, the top view of the contact structure is as follows: Figure 2 As shown in (a). The diameter of the second contact piece 2 is half the diameter of the first contact piece 1, and the slot depth is 2 mm. Under the action of 6 radial slots and 1 circumferential slot, the first contact piece 1 is divided into 12 conductive areas. The height of the second contact piece 2 is smaller than that of the first contact piece. Therefore, when the moving and static contacts are closed, the current flows directly to the other end contact after passing through the conductive rod 4-contact support 3-first contact piece 1. Compared with the traditional cup-shaped longitudinal magnetic structure, the current path is significantly shortened, which reduces the contact resistance and steady-state temperature rise, and improves the current carrying capacity of the circuit breaker.

[0116] In addition, the contact structure also helps to evenly distribute the current in the circular conductive area of ​​the first contact piece 1. When breaking a large current, as the moving contact and the stationary contact separate, the contact structure will generate multiple parallel vacuum arcs 5 on the first contact piece 1. Figure 2 As shown in (b), the greater the number of vacuum arcs 5 connected in parallel, the higher the utilization rate of the contact surface, which is beneficial for allocating arc energy and reducing arc erosion of the contacts.

[0117] Afterwards, as the contact opening distance increases, each segment of the vacuum arc 5 gradually converges toward the central area, such as Figure 2 As shown in (c), the annular groove and radial groove of the first contact piece 1 will hinder the movement of the arc, delay the generation time of the central concentrated arc, and help reduce the ablation amount of the contact.

[0118] When the vacuum arcs 5 converge at the center of the second contact piece 2, Figure 2 As shown in (d), it eventually evolves into a concentrated arc 6. The second contact piece 2 is made of a material with strong ablation resistance. Therefore, the degree of ablation of the contact by the concentrated arc 6 will be significantly reduced, and the splashing of metal droplets caused by ablation will be effectively alleviated, reducing the amount of arc plasma and improving the dielectric recovery ability after the arc.

[0119] In the embodiment of the present invention, the number of circumferential slots, the number of radial slots, the slot width, the slot depth of the first contact piece 1, and the size and material parameters of the second contact piece 2 are all parameters that need to be optimized collaboratively, and can be optimized and determined by a multi-objective optimization strategy. In practice, the control effect of the contact structure on the vacuum arcing process and the test results of the dielectric recovery capacity after the arc should be used as the main criteria for parameter selection.

[0120] In another embodiment, the lightweight large-capacity contact and the traditional cup-shaped longitudinal magnetic contact form an asymmetric contact system, such as Figure 3 As shown. The moving contact is a lightweight and large-capacity contact proposed in the present invention, including a first contact piece 1, a second contact piece 2, a contact support 3 and a moving conductive rod 4. The stationary contact is a traditional cup-shaped longitudinal magnetic contact, including a contact piece 7, a contact cup 8, and a stationary conductive rod 9. A stainless steel support is installed inside the contact to ensure mechanical strength. The asymmetric contact system shown in 3 is suitable for high current fast breaking occasions.

[0121] In high current fast breaking conditions, current transfer circuit breaker topology is usually used, such as As shown. The electromagnetic repulsion mechanism is used to drive the high-speed switch S to open. When the fault current appears, the high-speed switch S receives the opening command, and the moving and static contacts are quickly pulled apart by the electromagnetic repulsion mechanism, generating a vacuum arc. Under specific timing control, the transfer branch promptly injects reverse current into the high-speed switch S, forcing the current of the high-speed switch S to drop rapidly, generating an artificial zero crossing point, and the high-speed switch S is cut off at zero crossing, successfully withstanding the transient recovery voltage after the arc. Afterwards, the fault current is transferred to the energy consumption branch, the fault energy is effectively limited and quickly dissipated, and finally the high-current breaking is completed.

[0122] Both the moving and static contacts in the traditional cup-shaped longitudinal magnetic contact system can generate a longitudinal magnetic field, which is suitable for arc breaking conditions with a large opening distance. For the current transfer type of rapid breaking condition, the arc burning time of the vacuum arc is relatively short, only about 3 to 4 ms, which belongs to the arc breaking condition with a short opening distance. Under this condition, the longitudinal magnetic field of the cup-shaped longitudinal magnetic contact system is redundant. In addition, the cup-shaped longitudinal magnetic contact has a large moving mass and a large operating work, and it is difficult to meet the requirements of rapid breaking. If the moving contact is simply replaced with an ordinary flat contact, although the moving mass is reduced, the longitudinal magnetic field is greatly attenuated, which can easily lead to insufficient breaking capacity. Replacing the moving contact with the lightweight and large-capacity contact structure proposed in the present invention can not only achieve rapid opening, but also make up for the loss of arc control ability caused by the attenuation of the longitudinal magnetic field, and significantly improve the reliability of the asymmetric contact system for rapid breaking of large currents.

[0123] In the embodiment of the present invention, when the moving and static contacts are closed, it is assumed that the current flows in from the static end and flows out from the moving end. Figure 5 As shown in (a), the current path is "static end conductive rod-static end contact cup-static end contact piece-moving end contact piece-moving end contact cup-moving end conductive rod". Since multiple inclined slots are opened in the contact cup, the current path of the cup-shaped longitudinal magnetic contact system is longer. The current flow of the asymmetric contact system is shown in As shown in (b), the current path is "static end conductive rod-static end contact cup-static end contact piece-first contact piece-contact support-moving end conductive rod". In contrast, the current path of the asymmetric contact system is significantly shortened, which reduces the contact resistance and the steady-state temperature rise, and can effectively improve the current carrying capacity of the circuit breaker.

[0124] The height of the first contact piece 1 is greater than that of the second contact piece 2, so the moving contact in the closed state conducts current only through the first contact piece 1, and the current is concentrated in the annular area of ​​the first contact piece 1. In addition, the first contact piece 1 is provided with a plurality of annular grooves and radial grooves, which divide the contact piece into a plurality of conductive areas, which is conducive to realizing multi-point arcing when the contacts are separated, jointly sharing the arc energy, and improving the utilization rate of the contact surface.

[0125] In the embodiment of the present invention, the process of breaking high current by the asymmetric contact system can be divided into the following four stages: Figure 6 Medium (a) to Figure 6 As shown in (d).

[0126] Figure 6 (a) is the multi-point arcing stage of the asymmetric contact system. In this stage, as the contacts separate, multiple parallel vacuum arcs are simultaneously generated in the gap between the first contact piece 1 and the longitudinal magnetic contact.

[0127] Figure 6(b) is the arc column movement stage of the asymmetric contact system. In this stage, as the contact opening distance increases, the vacuum arc column is elongated, and under the action of the electromagnetic field in space, each segment of the vacuum arc gradually converges toward the center of the contact. The slot of the first contact piece 1 not only distributes the arc energy to multiple arc columns, but also hinders the arc column movement process in this stage, delays the appearance time of the central concentrated arc, and helps to reduce the amount of contact ablation.

[0128] Figure 6 (c) is the concentrated arc ablation stage of the asymmetric contact system. In this stage, multiple vacuum arcs converge to the central position of the second contact piece 2 to form a concentrated arc. The second contact piece 2 is made of a material with good arc ablation resistance, which can effectively reduce the degree of ablation of the contact material by the concentrated arc, reduce the generation of metal droplets and metal vapor, and enhance the ability of dielectric recovery after the arc.

[0129] Figure 6 (d) is the transfer breaking stage of the asymmetric contact system. In this stage, the transfer branch injects reverse current into the contact system according to a specific timing, and the contact current drops rapidly to the current zero point. The contact system successfully withstands the transient recovery voltage and finally completes the current breaking.

[0130] The cup-shaped longitudinal magnetic contact of the asymmetric contact system can also be replaced by a coil-type longitudinal magnetic contact or a permanent magnet-type longitudinal magnetic contact.

[0131] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0132] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A vacuum interrupter contact structure, characterized in that: These include, Conductive rod, A contact support is coaxially connected to the end of the conductive rod to support the first contact piece and the second contact piece. The first contact piece is coaxially connected to the contact support, and the first contact piece is a hollow annular structure, and the annular structure is provided with at least one annular groove and at least one radial groove to divide the vacuum arc and hinder the radial movement and annular movement of the arc column. The second contact piece is coaxially connected to the contact support and is located at the center of the first contact piece. The second contact piece is made of arc erosion resistant material.

2. The vacuum interrupter contact structure according to claim 1, characterized in that: Preferably, the second contact piece is a disc-shaped structure.

3. The vacuum interrupter contact structure according to claim 1, characterized in that: The first contact piece is a circular ring structure.

4. The vacuum interrupter contact structure according to claim 1, characterized in that: The first contact blade includes a plurality of radial slots.

5. The vacuum interrupter contact structure according to claim 1, characterized in that: The first contact piece includes a plurality of circumferential grooves.

6. The vacuum interrupter contact structure according to claim 1, characterized in that: The arc erosion resistant material includes copper-tungsten alloy or copper-tungsten-tungsten carbide alloy.

7. The vacuum interrupter contact structure according to claim 1, characterized in that: The arc erosion resistant material includes copper-chromium alloy.

8. The vacuum interrupter contact structure according to claim 1, characterized in that: The vacuum interrupter contact structure and the longitudinal magnetic contact together constitute an asymmetric contact system, wherein the vacuum interrupter contact structure serves as a moving contact, the longitudinal magnetic contact serves as a stationary contact, and a rapid operating mechanism is used to drive the contact movement, and the rapid operating mechanism includes an electromagnetic repulsion mechanism, a hydraulic spring mechanism or a high-speed motor mechanism.

9. The vacuum interrupter contact structure according to claim 8, characterized in that: The longitudinal magnetic contact includes a cup-shaped longitudinal magnetic contact, a coil-type longitudinal magnetic contact or a permanent magnet contact structure.

10. A method for breaking a vacuum interrupter contact structure according to any one of claims 1 to 9.

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