Vacuum circuit breaker

Abstract

A vacuum circuit breaker is provided, including a housing, an upper terminal board, a lower terminal board, a vacuum arc extinguishing device, and an operating mechanism having an insulated pull rod. One end of the insulated pull rod is connected to a moving end of the vacuum arc extinguishing device through the lower terminal board. The lower terminal board includes a three-layer structure having a soft connection, the first and third layers are each formed by a connection of stacked multiple layers of metal foil in a middle position and a single layer of copper sheet in an end position, the second layer is formed by a single layer of copper sheet, including a first part and a second part separated, the first and second parts of the second layer correspond to the copper sheets in the end position of the first and third layers, the three-layer structure is mechanically connected together at the copper sheet parts to form a first end and a second end, the first end is connected to the moving end of the vacuum arc extinguishing device, the second end provides a second terminal end, the multiple layers of metal foil of the first and third layers are arranged to provide a soft connection enabling relative movement of the two ends of the lower terminal board.

Description

Technical Field

[0001] This utility model relates to the field of low-voltage electrical technology, specifically to a vacuum circuit breaker. Background Technology

[0002] The statements in this section are merely to provide background information related to this utility model to aid in understanding it, and this background information does not necessarily constitute prior art.

[0003] In medium and low voltage power distribution systems, vacuum circuit breakers serve as core circuit protection and control devices, and their performance directly affects the safety, stability, and economy of the power distribution system. With the increasing demand for power supply capacity in power systems, the market is placing higher requirements on the current carrying capacity, integration level, and cost control of vacuum circuit breakers.

[0004] Traditional vacuum circuit breakers are limited by their overall structural design, resulting in generally low current carrying capacity. Early market products typically had a rated current of only 1250A, and even some improved models only reached 2500A, far from meeting the 4500A high-current requirements of next-generation power distribution systems. In high-current operating scenarios, the temperature rise problem of vacuum circuit breakers becomes even more pronounced: to increase current carrying capacity, more copper is needed to expand the conductive cross-sectional area. However, the dispersed copper material layout and unreasonable connection paths in traditional structures lead to a significant increase in equipment size along with the increase in copper usage. This conflicts with the power distribution system's demand for "miniaturized and compact" circuit breakers, making it difficult to achieve a balance between "high current carrying capacity - low temperature rise control - small size installation," severely limiting their application in high-capacity power distribution scenarios.

[0005] The moving conductor circuit is the core component of a vacuum circuit breaker, enabling coordinated current transmission and mechanical movement. Existing products primarily employ two connection methods: braided wire connection and swivel connection. While braided wire offers some flexibility to adapt to mechanical movement, its insufficient flexibility can easily interfere with the mechanism's operation during circuit breaker opening and closing, affecting operational reliability. Furthermore, braided wire has low current-carrying capacity and low heat dissipation efficiency, failing to meet the demands of high-current applications. The other method is the swivel connection, which, while improving current-carrying performance, is a medium-voltage solution requiring high precision in component manufacturing, leading to a significant increase in cost. Moreover, the rigid structure of the swivel connection is sensitive to installation precision; assembly deviations can easily cause poor contact, increasing the risk of temperature rise.

[0006] With the increasing demand for integrated protection functions in power distribution systems, the market requires vacuum circuit breakers to be compatible with low-voltage circuit breaker controllers to achieve accurate current-operated protection. However, existing products have not optimized their structure for this requirement and cannot integrate current transformers (CTs). They must rely on external equipment to achieve protection functions, which not only increases the overall size and cost of the equipment but also reduces the protection response speed. At the same time, some solutions that attempt to integrate CTs have maintenance obstacles. The CT is closely related to the main structure of the circuit breaker. When repairing or replacing the CT, the entire circuit breaker must be disassembled, which is cumbersome and time-consuming, seriously affecting the operation and maintenance efficiency of the power distribution system.

[0007] In summary, the existing vacuum circuit breakers have shortcomings in terms of high current carrying capacity, dynamic conduction circuit performance, integration adaptability, and maintenance convenience, and can no longer meet the current power distribution system's requirements for "high current, high reliability, high integration, and low cost". Utility Model Content

[0008] To address the aforementioned issues, it is necessary to develop a vacuum circuit breaker that overcomes the shortcomings of existing vacuum circuit breakers in terms of high current carrying capacity, dynamic conduction circuit performance, integration, and ease of maintenance.

[0009] To achieve the above objectives, this application provides a vacuum circuit breaker, comprising: a housing; an upper terminal block connected to the housing and providing a first terminal; a lower terminal block connected to the housing and providing a second terminal; a vacuum arc-extinguishing device disposed between the upper and lower terminal blocks, wherein the stationary terminal of the vacuum arc-extinguishing device is electrically connected to the upper terminal block, and the moving terminal of the vacuum arc-extinguishing device is electrically connected to the lower terminal block; and an operating mechanism having an insulating pull rod, one end of which passes through the lower terminal block and is connected to the moving terminal of the vacuum arc-extinguishing device. The operating mechanism pulls the insulating pull rod when a fault current is detected, thereby separating the moving and stationary contacts in the vacuum arc-extinguishing device; wherein the lower terminal block includes a flexible connection... The three-layer structure comprises: a first layer consisting of multiple stacked metal foils in the middle connected to single-layer copper sheets at both ends; a second layer consisting of single-layer copper sheets, including separate first and second portions; and a third layer consisting of multiple stacked metal foils in the middle connected to single-layer copper sheets at both ends. The first and second portions of the second layer correspond to the copper sheets at the ends of the first and third layers. The three layers are mechanically connected together at the copper sheet portions to form a first end and a second end. The first end is connected to the moving end of the vacuum arc-extinguishing device, and the second end provides the second terminal. The multiple stacked metal foils of the first and third layers are configured to provide a flexible connection that allows relative movement between the two ends of the lower terminal block.

[0010] In some embodiments, the multilayer metal foil and the copper sheet are bonded together by pressure welding.

[0011] In some embodiments, the multilayer metal foils are not connected to each other except at both ends.

[0012] In some embodiments, the first end of the lower terminal block has a through hole, and the insulating pull rod passes through the through hole and is tightened and fixed by a nut to achieve a fixed connection of the various layers of the lower terminal block.

[0013] In some embodiments, the thickness of the multilayer metal foil is 8-12 mm, the thickness of the single-layer copper sheet is 8-12 mm, and the thickness of the first and second portions of the second layer is 6-10 mm.

[0014] In some embodiments, the vacuum circuit breaker further includes a current transformer, which is sleeved on the second end and connected to the housing of the vacuum circuit breaker.

[0015] In some embodiments, the current transformer is detachably connected to the second end of the lower terminal block, and a positioning structure is provided between the current transformer and the housing, wherein the positioning structure is a positioning pin or a positioning slot.

[0016] In some embodiments, a support structure is provided below the third layer to support the lower wiring board.

[0017] In some embodiments, a reinforcing rib and a heat dissipation structure including heat sinks are provided below the support structure.

[0018] In some embodiments, a guide groove is provided at the end of the heat dissipation structure, and the guide groove is used to guide the movement of the insulating pull rod.

[0019] Compared with the prior art, the vacuum circuit breaker provided by this utility model has the following beneficial effects:

[0020] (1) The lower terminal block adopts a three-layer composite structure of "multi-layer metal foil + single-layer copper sheet". The multi-layer metal foil stacked in the middle greatly increases the conductive cross-sectional area and effectively reduces the skin effect. Combined with the excellent conductivity of copper, it effectively improves the current carrying capacity of the dynamic conductive circuit, which can meet the market demand for 4500A high current operation and solve the problem of insufficient current carrying capacity of existing products (such as 1250A and 2500A specifications).

[0021] (2) The stacked structure of multi-layer metal foil and the segmented design of soft connection expand the heat dissipation area, accelerate the heat dissipation during high current operation, avoid the problem of excessive temperature rise caused by poor heat dissipation in traditional structures, and achieve the balance of "high current carrying capacity - low temperature rise control".

[0022] (3) The multi-layer metal foil between the first and third layers of the lower terminal block constitutes a soft connection part, which has sufficient flexibility and deformation capability, and can realize the relative movement of the two ends of the lower terminal block. This avoids the problem of mechanical interference caused by insufficient flexibility in the traditional braided wire connection method, ensures the coordination between the operating mechanism and the conductive circuit during the circuit breaker opening and closing process, and improves the reliability of the on and off operation.

[0023] (4) The integrated three-layer structure of the lower terminal block provides installation space for the subsequent integrated current transformer (CT), and the core structure of the lower terminal block does not need to be disassembled when the CT is repaired or replaced, which provides convenience for maintenance operations.

[0024] (5) The design of the insulating pull rod passing through the lower terminal block to connect the moving end of the vacuum arc extinguishing device not only realizes the precise transmission between the operating mechanism and the vacuum arc extinguishing device, but also isolates the conductive circuit from the operating mechanism through the insulation characteristics of the insulating pull rod, avoiding the risk of electrical breakdown and improving the overall operational safety. Attached Figure Description

[0025] Figure 1 A schematic diagram of a vacuum circuit breaker according to an embodiment of the present invention is shown.

[0026] Figure 2 A schematic diagram of a vacuum circuit breaker including three vacuum arc-extinguishing devices according to an embodiment of the present invention is shown.

[0027] Figure 3 A schematic diagram of the three-layer structure of the lower wiring board before pressure welding is shown according to an embodiment of the present invention.

[0028] Figure 4 A schematic diagram of the three-layer structure of the lower wiring board after pressure welding according to an embodiment of the present invention is shown.

[0029] Figure 5 A schematic diagram of a vacuum circuit breaker including a current transformer according to an embodiment of the present invention is shown.

[0030] Figure 6 A side view of a vacuum circuit breaker according to an embodiment of the present invention is shown.

[0031] Figure 7 A schematic diagram of a support structure according to an embodiment of the present invention is shown.

[0032] Figure 8 A schematic diagram of the structure of an insulating ring according to an embodiment of the present invention is shown.

[0033] The meanings of the labels in the attached diagram are as follows:

[0034] 1-Upper terminal block; 2-Housing; 3-Vacuum arc extinguishing device; 4-Lower terminal block; 5-Support structure; 6-Insulating pull rod; 7-Operating mechanism; 8-Stationary end; 9-Moving end; 10-Flexible connection; 11-First layer; 12-Second layer; 13-Third layer; 14-First part; 15-Second part; 16-Current transformer; 17-Copper sheet; 18-Multi-layer metal foil; 19-Through hole; 20-Heat dissipation structure; 21-Reinforcing rib; 22-Guide groove; 23-Mounting hole; 24-Insulating ring. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments given in this utility model are for illustrative purposes only and do not limit the scope of protection of this utility model.

[0036] like Figure 1 and 3 As shown, this application provides a vacuum circuit breaker, including: a housing 2, an upper terminal block 1, a lower terminal block 4, a vacuum arc-extinguishing device 3, and an operating mechanism 7. The upper terminal block 1 is connected to the housing 2 and provides a first terminal, and the lower terminal block 4 is connected to the housing 2 and provides a second terminal. The vacuum arc-extinguishing device 3 is disposed between the upper terminal block 1 and the lower terminal block 4. The stationary end 8 of the vacuum arc-extinguishing device 3 is electrically connected to the upper terminal block 1, and the moving end 9 of the vacuum arc-extinguishing device 3 is electrically connected to the lower terminal block 4. The operating mechanism 7 has an insulating pull rod 6, one end of which passes through the lower terminal block 4 and is connected to the moving end 9 of the vacuum arc-extinguishing device 3. When a fault current is detected, the operating mechanism 7 pulls the insulating pull rod 6, causing the moving contact and the stationary contact in the vacuum arc-extinguishing device 3 to separate. The lower terminal block 4 includes a three-layer structure with a flexible connection 10. The first layer 11 is formed by connecting multiple layers of metal foil 18 stacked in the middle and single layers of copper sheets 17 at both ends. The thickness of each individual foil layer of the multilayer metal foil 18 is selected to be less than the skin depth at the target operating frequency, so that each foil layer can effectively participate in conduction, thereby significantly reducing the AC resistance under high-frequency conditions. The second layer 12 is formed by a single copper sheet 17, including a separated first portion 14 and a second portion 15. Similar to the structure of the first layer 11, the third layer 13 is formed by connecting the multilayer metal foil 18 in the middle position and the single copper sheets 17 at both ends. The first portion 14 and the second portion 15 of the second layer 12 correspond to the copper sheets 17 at both ends of the first layer 11 and the third layer 13, so that the three-layer structure can be mechanically connected together at the copper sheet portion to form a first end and a second end, wherein the first end is connected to the moving end 9 of the vacuum arc extinguishing device 3, and the second end provides a second terminal. The multilayer metal foil 18 of the first layer 11 and the third layer 13 is configured to provide a flexible connection 10 that allows the two ends of the lower terminal block 4 to move relative to each other.

[0037] Specifically, such as Figure 3 and 4 As shown, the lower terminal block 4 employs a three-layer composite structure formed by welding multiple layers of metal foil 18 and a single layer of copper sheet 17. The stacked multiple layers of metal foil 18 significantly increase the conductive cross-sectional area and effectively reduce the skin effect. Combined with the excellent conductivity of copper, this effectively enhances the current-carrying capacity of the dynamic conductive circuit, meeting the market demand for 4500A high-current operation and solving the problem of insufficient current-carrying capacity in existing products (such as 1250A and 2500A specifications). The stacked structure of the multiple layers of metal foil 18 and the segmented design of the flexible connection 10 expand the heat dissipation area, accelerate heat dissipation during high-current operation, avoid the problem of excessive temperature rise caused by poor heat dissipation in traditional structures, and achieve a balance between high current carrying capacity and low temperature rise control.

[0038] Specifically, such as Figure 3 As shown, the multi-layer metal foil 18 between the first layer 11 and the third layer 13 of the lower terminal block 4 constitutes a flexible connection part to provide sufficient flexible deformation capability, thereby allowing relative movement between the two ends of the lower terminal block 4. This avoids the problem of mechanism interference caused by insufficient flexibility in traditional braided wire connection methods, thereby ensuring the coordination between the operating mechanism and the conductive circuit during the circuit breaker opening and closing process, and improving the reliability of the switching operation.

[0039] In some embodiments, such as Figure 2 As shown, the vacuum circuit breaker can use three vacuum arc extinguishing devices 3, which can adapt to the operating characteristics and safety requirements of a three-phase power system. Specifically, the three vacuum arc extinguishing devices 3 can solve the functional defects of single or double arc extinguishing devices in a three-phase scenario by making each phase an independent unit. The number of vacuum arc extinguishing devices 3 can be set according to actual needs.

[0040] Specifically, such as Figure 1 and 5 As shown, the insulating rod 6 passes through the lower terminal block 4 and connects to the moving end 9 of the vacuum arc extinguishing device 3. This not only enables precise transmission between the operating mechanism 7 and the vacuum arc extinguishing device 3, but also isolates the conductive circuit from the operating mechanism 7 through the insulating characteristics of the insulating rod 6, thereby avoiding the risk of electrical breakdown and improving overall operational safety.

[0041] In some embodiments, such as Figure 4 As shown, the multi-layer metal foil 18 and the copper sheet 17 are connected together by pressure welding. This pressure welding connection creates a tight metal-to-metal interface, significantly reducing contact resistance. Under high current conditions in the vacuum circuit breaker, low contact resistance effectively reduces energy loss and heat generation, preventing localized overheating caused by excessive contact resistance, which could affect the normal operation and lifespan of the lower terminal block 4, thus ensuring the stable operation of the entire vacuum circuit breaker.

[0042] In some embodiments, the multilayer metal foil 18 can be aluminum foil, copper foil, or alloy foil; preferably, the multilayer metal foil 18 is copper foil. Copper has excellent electrical conductivity, which can effectively reduce resistance during current transmission, reduce power loss, and improve circuit efficiency.

[0043] In some embodiments, the multiple layers of metal foil 18 are not connected to each other except at both ends. Thus, when the lower terminal block 4 bends, each layer of metal foil can independently adapt to deformation, preventing localized stress concentration due to interlayer fixation, thereby reducing the risk of metal foil cracking and breakage, and extending service life. Furthermore, the multiple layers of metal foil 18 form a flexible connection 10 with the first layer 11 and the third layer 13 of the lower terminal block 4, possessing sufficient flexible deformation capability to allow relative movement between the two ends of the lower terminal block 4.

[0044] In some embodiments, such as Figure 3 and 4 As shown, the first end of the lower terminal block 4 has a through hole 19, as... Figure 5 As shown, the insulating rod 6 passes through the through hole 19 and is tightened and fixed by the nut to achieve a fixed connection between the layers of the lower terminal block 4. Specifically, the first layer 11, the second layer 12, and the third layer 13 of the lower terminal block 4 each have corresponding through holes 19, and the diameter of the through holes 19 is larger than the diameter of the insulating rod 6. After the insulating rod 6 passes through the through hole 19, the axial clamping force of the nut can apply uniform and continuous pressure to the multi-layer structure of the lower terminal block 4. The insulating rod 6, through its own insulation, blocks the electrical connection between the lower terminal block 4 and the conductive circuit, improving the overall operational safety.

[0045] In some embodiments, such as Figure 3 As shown, the thickness of the multilayer metal foil 18 is 8-12 mm, the thickness of the single-layer copper sheet 17 is 8-12 mm, and the thickness of the first part 14 and the second part 15 of the second layer 12 is 6-10 mm. Preferably, the thickness of the multilayer metal foil 18 can be set to be the same as the thickness of the single-layer copper sheet 17, which ensures that the overall thickness of the lower terminal block 4 is uniform, avoids steps or protrusions due to thickness differences, and facilitates precise docking with the vacuum arc extinguishing device 3 and the insulating pull rod 6. Preferably, the thickness of each metal foil layer is 0.02-0.05 mm, which confines the eddy currents in each metal foil layer to a very small thickness range, preventing the formation of large-size circulating currents and significantly reducing the loss intensity.

[0046] In some embodiments, such as Figure 5 As shown, the vacuum circuit breaker also includes a current transformer 16, which is sleeved on the second end of the flexible connection 10 and fixed to the housing 2 of the vacuum circuit breaker.

[0047] In some embodiments, the current transformer 16 is detachably connected to the second end of the lower terminal block 4. Specifically, one end of the current transformer 16 is detachably connected to the second end of the lower terminal block 4 through the mounting hole 23 on the lower terminal block 4, and the other end of the current transformer 16 is connected to the housing 2 of the vacuum circuit breaker. In some embodiments, a positioning structure is provided between the current transformer 16 and the housing 2. The positioning structure is a positioning pin or a positioning slot (not shown). This ensures that the relative position of the current transformer 16 and the housing 2 is fixed.

[0048] In some embodiments, such as Figure 5 As shown, a support structure 5 is provided below the third layer 13 to support the lower terminal block 4. Specifically, the support structure 5 can be designed as a groove or step structure that matches the bottom of the lower terminal block 4, so that it can both support the lower terminal block 4 and restrict its horizontal displacement and rotation.

[0049] In some embodiments, such as Figure 7 As shown, a reinforcing rib 21 and a heat dissipation structure 20 including heat sinks are provided below the support structure 5. This ensures the overall stability of the support structure 5 and guides heat to diffuse outward, preventing heat from accumulating in the narrow space between the support structure 5 and the third layer 13.

[0050] In some embodiments, such as Figure 7 As shown, a guide groove 22 is provided at the end of the heat dissipation structure 20. The guide groove 22 is used to guide the movement of the insulating pull rod 6. Specifically, as shown... Figure 5 As shown, the guide groove 22 is engaged with... Figure 8 The insulating ring 24 shown is fitted onto the housing 2. The size of the insulating ring 24 is larger than that of the insulating rod 6. Therefore, when the insulating rod 6 moves up and down under the action of the operating mechanism 7, the insulating ring 24 and the supporting structure 5 will not move with the insulating rod 6. In this way, the stable movement of the insulating rod 6 is ensured, and the unnecessary movement interference of the insulating ring 24 and the supporting structure 5 is avoided.

[0051] In some embodiments, the travel distance of the insulating rod 6 is 4-8 mm, which can be specifically designed according to the breaking distance of the moving and stationary contacts of the vacuum arc extinguishing device 3. If the travel distance of the insulating rod 6 is too small (e.g., less than 4 mm), the breaking distance of the contacts of the vacuum arc extinguishing device 3 will be insufficient, and the arc will not be extinguished quickly in the vacuum; if the travel distance of the insulating rod 6 is too large (e.g., greater than 8 mm), excessive breaking may shorten the service life of the vacuum arc extinguishing device 3.

[0052] The lower terminal block 4 of the vacuum circuit breaker provided in this utility model adopts a three-layer composite structure formed by pressure welding of multiple layers of metal foil 18 and single-layer copper sheet 17. The multi-layer metal foil 18 stacked in the middle greatly increases the conductive cross-sectional area. Combined with the excellent conductivity of copper, it effectively improves the current carrying capacity of the moving conductive circuit, which can meet the market demand for 4500A high current operation and solve the problem of insufficient current carrying capacity of existing products (such as 1250A and 2500A specifications). The stacked structure of the multi-layer metal foil 18 and the upper and lower segmented design of the flexible connection 10 expand the heat dissipation area, accelerate the heat dissipation during high current operation, avoid the problem of excessive temperature rise caused by poor heat dissipation in traditional structures, and achieve a balance between high current carrying capacity and low temperature rise control.

[0053] Although the present invention has been described through preferred embodiments, the present invention is not limited to the embodiments described herein, and includes various changes and variations without departing from the scope of the present invention.

Claims

1. A vacuum circuit breaker, characterized in that, include: case; An upper terminal block, which is connected to the housing and provides a first terminal; The lower terminal block is connected to the housing and provides a second terminal. A vacuum arc extinguishing device is disposed between the upper terminal block and the lower terminal block. The stationary end of the vacuum arc extinguishing device is electrically connected to the upper terminal block, and the moving end of the vacuum arc extinguishing device is electrically connected to the lower terminal block. as well as An operating mechanism with an insulating pull rod is provided. One end of the insulating pull rod passes through the lower terminal block and is connected to the moving end of the vacuum arc extinguishing device. When the operating mechanism detects a fault current, it pulls the insulating pull rod to separate the moving contact and the stationary contact in the vacuum arc extinguishing device. The lower terminal block includes a three-layer structure with flexible connections. The first layer is formed by connecting multiple layers of metal foil stacked in the middle and single-layer copper sheets at both ends. The second layer is formed by a single-layer copper sheet, including separate first and second portions. The third layer is formed by connecting multiple layers of metal foil in the middle and single-layer copper sheets at both ends. The first and second portions of the second layer correspond to the copper sheets at the ends of the first and third layers. The three-layer structure is mechanically connected together at the copper sheet portions to form a first end and a second end. The first end is connected to the moving end of the vacuum arc extinguishing device, and the second end provides the second terminal. The multiple layers of metal foil in the first and third layers are configured to provide a flexible connection that allows the two ends of the lower terminal block to move relative to each other.

2. The vacuum circuit breaker according to claim 1, characterized in that, The multilayer metal foil and the copper sheet are joined together by pressure welding.

3. The vacuum circuit breaker according to claim 1, characterized in that, Except at both ends, the multilayer metal foils are not connected to each other.

4. The vacuum circuit breaker according to claim 1, characterized in that, The first end of the lower terminal block has a through hole, and the insulating pull rod passes through the through hole and is tightened and fixed by a nut to achieve a fixed connection of the various layers of the lower terminal block.

5. The vacuum circuit breaker according to claim 1, characterized in that, The thickness of the multilayer metal foil is 8-12mm, the thickness of the single-layer copper sheet is 8-12mm, and the thickness of the first and second parts of the second layer is 6-10mm.

6. The vacuum circuit breaker according to claim 1, characterized in that, It also includes a current transformer, which is sleeved on the second end and connected to the housing of the vacuum circuit breaker.

7. The vacuum circuit breaker according to claim 6, characterized in that, The current transformer is detachably connected to the second end of the lower terminal block, and a positioning structure is provided between the current transformer and the housing, which is a positioning pin or a positioning slot.

8. The vacuum circuit breaker according to claim 1, characterized in that, A support structure is provided below the third layer to support the lower wiring board.

9. The vacuum circuit breaker according to claim 8, characterized in that, A reinforcing rib and a heat dissipation structure including heat sinks are provided below the support structure.

10. The vacuum circuit breaker according to claim 9, characterized in that, A guide groove is provided at the end of the heat dissipation structure to guide the movement of the insulating pull rod.

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