Arc extinguishing chamber of circuit breaker, circuit breaker, circuit breaker opening control method

Abstract

The application discloses an arc extinguishing chamber of a circuit breaker, the circuit breaker and a tripping control method of the circuit breaker. The arc extinguishing chamber comprises a nozzle, a compression cylinder and a movable contact connected with the nozzle. The compression cylinder comprises a movable part and a fixed part. The movable part and the fixed part jointly enclose at least two gas chambers. Each gas chamber is communicated with the nozzle. The movable part is connected with the movable contact. When the movable part moves with the movable contact to a tripping direction, the volume of each gas chamber is reduced. When the circuit breaker is tripped, the movable contact firstly experiences a speed-up stage, then experiences a high-speed movement stage, then experiences a low-speed movement stage, and then experiences a buffer stage. The average speed of the high-speed movement stage is higher than that of the low-speed movement stage. According to the application, the tripping time can be prolonged by reducing the tripping speed, the size of the arc extinguishing chamber does not need to be increased, the tripping time of the circuit breaker can cover the arc window time, and the circuit breaker has enough opening distance in a short arc time.

Description

Technical Field

[0001] This application relates to the field of circuit breaker technology, and in particular to an arc-extinguishing chamber of a circuit breaker, a circuit breaker, and a method for controlling the tripping of a circuit breaker. Background Technology

[0002] A successful circuit breaker tripping time must cover the arcing window time. For low-frequency circuit breakers, the arcing window time is longer, therefore the required tripping time is also longer.

[0003] Currently, the two main measures to extend the tripping time are: (1) extending the tripping stroke, which inevitably requires increasing the length of the circuit breaker's arc-extinguishing chamber; and (2) reducing the tripping speed, while simultaneously increasing the cross-sectional dimensions of the circuit breaker's arc-extinguishing chamber. Both of these measures will lead to an increase in the size and cost of the circuit breaker, which is not conducive to improving the product competitiveness of the circuit breaker.

[0004] Therefore, how to extend the circuit breaker's opening time without increasing its size, so as to ensure that the circuit breaker's opening time covers the arcing window time, is a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] To solve the above-mentioned technical problems, this application provides an arc-extinguishing chamber for a circuit breaker, including a nozzle, a pressure cylinder, and a moving contact connected to the nozzle. The pressure cylinder includes a movable part and a fixed part, which together enclose at least two air chambers. Each air chamber is connected to the nozzle. The movable part is connected to the moving contact. When the movable part moves in the opening direction with the moving contact, the volume of each air chamber decreases.

[0006] In one embodiment of the arc-extinguishing chamber of a circuit breaker, the gas chambers are arranged sequentially and connected sequentially in the direction of movement of the moving contact.

[0007] In one embodiment of the arc-extinguishing chamber of a circuit breaker, the movable component and the fixed component are interlocked and clearance-fitted with each other along the moving direction of the moving contact. The movable component is provided with a plurality of movable compressed air end faces spaced apart in sequence along the moving direction of the moving contact, and the fixed component is provided with a plurality of fixed compressed air end faces spaced apart in sequence along the moving direction of the moving contact. Each fixed compressed air end face and each movable compressed air end face is arranged facing each other in the moving direction of the moving contact, and a single air chamber is formed between the single fixed compressed air end face and the single movable compressed air end face arranged facing each other.

[0008] In one embodiment of the arc-extinguishing chamber of a circuit breaker, the movable part and the fixed part are arranged coaxially.

[0009] In one embodiment of the arc-extinguishing chamber of a circuit breaker, the fixed component is provided with at least one set of connecting channels, and every two adjacent air chambers are connected through one set of connecting channels.

[0010] In one embodiment of the arc-extinguishing chamber of a circuit breaker, a connecting portion is provided between every two adjacent fixed compressed air end faces of the fixed component, and a connecting channel is provided in the connecting portion. One port of the connecting channel is formed on the outer peripheral surface of the connecting portion, and the other port is formed on the fixed compressed air end face of the connecting portion near the nozzle end.

[0011] This application also provides a circuit breaker including an arc-extinguishing chamber, wherein the arc-extinguishing chamber is an arc-extinguishing chamber as described in any of the above claims.

[0012] This application also provides a circuit breaker tripping control method, wherein the circuit breaker is a circuit breaker using the above-mentioned arc-extinguishing chamber. When the circuit breaker trips, the moving contact is controlled to first go through an acceleration stage, then a high-speed movement stage, then a low-speed movement stage, and then a buffer stage. The average speed of the high-speed movement stage is higher than the average speed of the low-speed movement stage.

[0013] One implementation of the circuit breaker tripping control method controls the high-speed movement phase to end at the end of the short arcing period.

[0014] In one embodiment of the circuit breaker tripping control method, the average speed v1 of the high-speed movement phase and the average speed v2 of the low-speed movement phase satisfy: 2*v2≤v1.

[0015] The circuit breaker using the arc-extinguishing chamber provided in this application can extend the opening time by reducing the opening speed, without increasing the size of the arc-extinguishing chamber.

[0016] The circuit breaker tripping control method provided in this application can ensure that the tripping time of the circuit breaker covers the arcing window time and that the circuit breaker has sufficient opening distance during short arcing time. Attached Figure Description

[0017] Figure 1 A partial schematic diagram of an embodiment of the arc-extinguishing chamber of the circuit breaker provided in this application;

[0018] Figure 2 A partial schematic diagram of another embodiment of the arc-extinguishing chamber of the circuit breaker provided in this application;

[0019] Figure 3 A comparison of the tripping characteristic curves of the circuit breaker using the tripping control method provided in this application and the conventional tripping control method.

[0020] The annotations in the attached figures are explained as follows:

[0021] 10 moving contact, 10a moving main contact, 10b moving arc contact;

[0022] 20 stationary contact, 20a stationary main contact, 20b stationary arc contact;

[0023] 30 nozzles;

[0024] 401 First air chamber, 402 Second air chamber, 403 Third air chamber;

[0025] 50 Movable component, 501 Movable inner sleeve, 502 Movable outer sleeve, A1 First movable air-compressing end face, A2 Second movable air-compressing end face, A3 Third movable air-compressing end face;

[0026] 60 Fixed component, 601 Fixed inner sleeve, 602 Fixed outer sleeve, 603 Connecting part, B1 First fixed compressed air end face, B2 Second fixed compressed air end face, B3 Third fixed compressed air end face, C Connecting channel. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solution of this application, the technical solution of this application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1 The arc-extinguishing chamber of the circuit breaker includes a moving contact 10, a stationary contact 20, a nozzle 30, and a compressor cylinder. The moving contact 10 includes a moving main contact 10a and a moving arc contact 10b, and the stationary contact 20 includes a stationary main contact 20a and a stationary arc contact 20b. The nozzle 30 is connected to the moving contact 10, and moves along with the moving contact 10. The compressor cylinder includes a movable part 50 and a fixed part 60. The movable part 50 is connected to the moving contact 10, and moves along with the moving contact 10.

[0029] The movable part 50 and the fixed part 60 of the air cylinder enclose and form at least two air chambers. Figure 1 In the illustrated embodiment, the movable part 50 and the fixed part 60 enclose two air chambers, a first air chamber 401 and a second air chamber 402. In actual implementation, the number of air chambers is not limited to two; there can be more than two, for example... Figure 2 In the illustrated embodiment, the movable part 50 and the fixed part 60 enclose three air chambers: a first air chamber 401, a second air chamber 402, and a third air chamber 403. Each air chamber is connected to the nozzle 30, either directly or indirectly.

[0030] When the moving contact 10 moves in the opening direction, the movable part 50 reduces the volume of each air chamber. Specifically, when the circuit breaker opens, the moving contact 10 moves away from the stationary contact 20, causing the moving main contact 10a to separate from the stationary main contact 20a first, followed by the moving arc contact 10b and the stationary arc contact 20b separating, generating an electric arc in the nozzle 30. The movable part 50 of the pressure cylinder moves with the moving contact 10 in the direction away from the stationary contact 20 (i.e., the opening direction), reducing the volume of each air chamber. When the air pressure in the air chamber reaches the target value, gas is ejected from the nozzle 30 to extinguish the arc.

[0031] Traditional circuit breakers only have one air chamber. If the opening time is extended by reducing the opening speed, the air pressure in the air chamber will not reach the target value, resulting in arc extinguishing failure. Therefore, in the past, in order to ensure successful arc extinguishing when the opening speed was reduced, the cross-sectional size of the arc extinguishing chamber would be increased. This would increase the cost of the circuit breaker and reduce the product's competitiveness.

[0032] In this application, multiple air chambers are provided, and each air chamber is connected to the nozzle 30. The volume of each air chamber is reduced during the opening process. In this way, at the same opening speed, the air pressure that can be achieved is the sum of the air pressures of each air chamber. Therefore, it can ensure that the arc can be successfully extinguished even when the opening speed is reduced. Moreover, since each air chamber is formed by the same movable part 50 and fixed part 60, multiple air chambers can be accommodated without increasing the size of the arc extinguishing chamber. Therefore, it is not necessary to increase the size of the arc extinguishing chamber (including the length and cross-sectional dimensions), thus avoiding the increase in the cost of the circuit breaker.

[0033] Therefore, for circuit breakers using the aforementioned arc-extinguishing chamber, the opening time can be extended by reducing the opening speed, without needing to increase the size of the arc-extinguishing chamber.

[0034] Specifically, such as Figure 1 and Figure 2 As shown, each air chamber can be arranged sequentially and connected sequentially in the moving direction of the moving contact 10. Figure 1 In the process, the first air chamber 401 is directly connected to the nozzle 30 through the connecting hole T, and the second air chamber 402 is connected to the first air chamber 401, thereby indirectly connected to the nozzle 30 through the first air chamber 401. Figure 2 In the process, the first air chamber 401 is directly connected to the nozzle 30 through the connecting hole T, the second air chamber 402 is connected to the first air chamber 401, and thus indirectly connected to the nozzle 30 through the first air chamber 401, and the third air chamber 403 is connected to the second air chamber 402, and thus indirectly connected to the nozzle 30 through the second air chamber 402 and the first air chamber 401.

[0035] Arranging and connecting the gas chambers sequentially along the moving direction of the moving contact 10 serves two purposes. First, it fully utilizes the internal space of the arc-extinguishing chamber, allowing more gas chambers to be accommodated without increasing its size. Second, it connects the gas chambers in series, enabling the gas pressure in each chamber to gradually increase towards the nozzle 30, ultimately creating high pressure near the nozzle 30 and achieving a better arc-extinguishing effect. Alternatively, if the cross-sectional dimensions of the arc-extinguishing chamber allow, the gas chambers can be arranged on the same cross-section and directly connected to the nozzle 30 via the connecting hole T, thus placing them in parallel.

[0036] Specifically, the movable part 50 and the fixed part 60 are interlocked and fitted with a gap along the moving direction of the moving contact 10. A guide lubrication device and a conductive contact can be provided in the gap to ensure electrical conduction between the movable part 50 and the fixed part 60.

[0037] Furthermore, the movable component 50 is provided with a plurality of movable compressed air end faces at intervals along the moving direction of the movable contact 10, and the fixed component 60 is provided with a plurality of fixed compressed air end faces at intervals along the moving direction of the movable contact 10. Each fixed compressed air end face and each movable compressed air end face are arranged opposite each other in the moving direction of the movable contact 10, and a single air chamber is formed between the single fixed compressed air end face and the single movable compressed air end face arranged opposite each other.

[0038] Figure 1 The device includes two movable air end faces, namely a first movable air end face A1 and a second movable air end face A2, and two fixed air end faces, namely a first fixed air end face B1 and a second fixed air end face B2. A first air chamber 401 is formed between the first movable air end face A1 and the first fixed air end face B1, and a second air chamber 402 is formed between the second movable air end face A2 and the second fixed air end face B2.

[0039] Figure 2 The device includes three movable air end faces, namely the first movable air end face A1, the second movable air end face A2, and the third movable air end face A3, and three fixed air end faces, namely the first fixed air end face B1, the second fixed air end face B2, and the third fixed air end face B3. The first air chamber 401 is formed between the first movable air end face A1 and the first fixed air end face B1, the second air chamber 402 is formed between the second movable air end face A2 and the second fixed air end face B2, and the third air chamber 403 is formed between the third movable air end face A3 and the third fixed air end face B3.

[0040] In detail, the movable part 50 and the fixed part 60 are interlocked in the following three cases: the first case is that the movable part 50 is fitted outside the fixed part 60; the second case is that the fixed part 60 is fitted outside the movable part 50; and the third case is that a part of the movable part 50 is fitted outside the fixed part 60, and a part of the fixed part 60 is fitted outside the movable part 50.

[0041] Figure 1 The middle one is the third case. Figure 1 In the process, the movable component 50 includes a movable inner sleeve 501 and a movable outer sleeve 502, and the fixed component 60 includes a fixed inner sleeve 601 and a fixed outer sleeve 602. The fixed inner sleeve 601 is fitted over the movable inner sleeve 501, the movable outer sleeve 502 is fitted over the fixed inner sleeve 601, and the fixed outer sleeve 602 is fitted over the movable outer sleeve 502. The fixed outer sleeve 602 has a fixed stop at the end away from the nozzle 30, and the movable outer sleeve 502 has a movable stop at the end near the nozzle 30. A first movable compressed air end face A1 is formed on the end face of the movable stop away from the nozzle 30, a second movable compressed air end face A2 is formed on the end face of the movable outer sleeve 502 away from the nozzle 30, a first fixed compressed air end face B1 is formed on the end face of the fixed inner sleeve 601 near the nozzle 30, and a second fixed compressed air end face B2 is formed on the end face of the fixed stop near the nozzle 30. The first air chamber 401 is formed by the first movable air end face A1, the inner peripheral surface of the movable outer sleeve 502, the outer peripheral surface of the movable inner sleeve 501, and the first fixed air end face B1. The second air chamber 402 is formed by the second movable air end face A2, the inner peripheral surface of the fixed outer sleeve 602, the outer peripheral surface of the fixed inner sleeve 601, and the second fixed air end face B2.

[0042] Specifically, the movable part 50 and the fixed part 60 can be arranged coaxially, that is, their central axes are collinear. This is more conducive to ensuring that the clearance fit between the two meets the requirements compared to an eccentric arrangement.

[0043] Specifically, the fixed component 60 may be provided with at least one set of connecting channels C, and in the moving direction of the moving contact 10, every two adjacent air chambers are connected through a set of connecting channels C. Figure 1 In the middle, the first air chamber 401 and the second air chamber 402 are connected by a set of connecting channels C. Figure 2 In the middle, the first air chamber 401 and the second air chamber 402 are connected by a set of connecting channels C, and the second air chamber 402 and the third air chamber 403 are connected by another set of connecting channels C.

[0044] In the illustrated embodiment, a connecting portion 603 is provided between every two adjacent fixed compressed air end faces of the fixed component 60, and a connecting channel C is provided in the connecting portion 603. One port of the connecting channel C (C2 in the figure) is formed on the outer peripheral surface of the connecting portion 603, and the other port (C1 in the figure) is formed on the fixed compressed air end face of the connecting portion 603 near the nozzle 30. By providing the connecting channel C in the connecting portion 603 of the fixed component 60, the internal space of the arc-extinguishing chamber can be saved to the maximum extent.

[0045] This application also provides a circuit breaker including the aforementioned arc-extinguishing chamber. Furthermore, this application provides a method for controlling the tripping of a circuit breaker employing the aforementioned arc-extinguishing chamber.

[0046] like Figure 3 The tripping control method is as follows: when the circuit breaker trips, the moving contact is controlled to first go through an acceleration stage, then a high-speed movement stage, then a low-speed movement stage, and then a buffer stage. The average speed of the high-speed movement stage is higher than the average speed of the low-speed movement stage.

[0047] In conventional circuit breaker tripping, there is a high-speed constant-speed phase between the acceleration phase and the buffer phase. This application divides this conventional high-speed constant-speed phase into two stages: a first stage is a high-speed motion phase, where the average speed remains essentially the same as the average speed of the conventional high-speed constant-speed phase; the second stage is a low-speed motion phase, where the average speed is significantly lower than the average speed of the high-speed motion phase. Specifically, the average speed v1 of the high-speed motion phase and the average speed v2 of the low-speed motion phase preferably satisfy: 2*v2≤v1.

[0048] By adopting this tripping control method, the average speed of the phase between the acceleration phase and the buffer phase can be reduced, thereby extending the tripping time.

[0049] Specifically, the high-speed movement phase can be controlled to end at the end of the short arcing time. In other words, the high-speed movement phase can be controlled to end at the beginning of the arcing window time. In this way, while extending the tripping time, the circuit breaker can also ensure that it has a sufficient opening distance during the short arcing time.

[0050] The above examples illustrate the principles and implementation methods of this application. The descriptions of these embodiments are merely for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. The arc-extinguishing chamber of a circuit breaker, comprising a nozzle (30), a compressor cylinder, and a moving contact (10) connected to the nozzle (30), characterized in that, The air cylinder includes a movable part (50) and a fixed part (60). The movable part (50) and the fixed part (60) together enclose at least two air chambers. Each air chamber is connected to the nozzle (30). The movable part (50) is connected to the moving contact (10). When the movable part (50) moves in the opening direction with the moving contact (10), the volume of each air chamber is reduced, so that the air pressure of each air chamber can be superimposed in the direction close to the nozzle (30), thereby finally forming a high pressure for arc extinguishing near the nozzle (30). Each of the air chambers is arranged sequentially and connected sequentially in the moving direction of the moving contact (10); The movable component (50) and the fixed component (60) are interlocked and fitted with a clearance along the moving direction of the moving contact (10). The movable component (50) is provided with a plurality of movable air-pressurized end faces at intervals along the moving direction of the moving contact (10). The fixed component (60) is provided with a plurality of fixed air-pressurized end faces at intervals along the moving direction of the moving contact (10). Each fixed air-pressurized end face and each movable air-pressurized end face are arranged facing each other in the moving direction of the moving contact (10). A single air chamber is formed between the single fixed air-pressurized end face and the single movable air-pressurized end face arranged facing each other.

2. The arc-extinguishing chamber of the circuit breaker according to claim 1, characterized in that, The movable part (50) and the fixed part (60) are arranged coaxially.

3. The arc-extinguishing chamber of the circuit breaker according to claim 1 or 2, characterized in that, The fixing component (60) is provided with at least one set of communication channels (C), and every two adjacent air chambers are connected through one set of communication channels (C).

4. The arc-extinguishing chamber of the circuit breaker according to claim 3, characterized in that, A connecting portion (603) is provided between every two adjacent fixed compressed air end faces of the fixed component (60), and a connecting channel (C) is provided on the connecting portion (603). One port of the connecting channel (C) is formed on the outer peripheral surface of the connecting portion (603), and the other port is formed on the fixed compressed air end face of the connecting portion (603) near the nozzle (30).

5. A circuit breaker, including an arc-extinguishing chamber, characterized in that, The arc-extinguishing chamber is the arc-extinguishing chamber described in any one of claims 1-4.

6. A method for controlling the tripping of a circuit breaker, wherein the circuit breaker is a circuit breaker employing an arc-extinguishing chamber as described in any one of claims 1-5, characterized in that, When the circuit breaker is tripped, the control moving contact first goes through an acceleration stage, then a high-speed movement stage, then a low-speed movement stage, and then a buffer stage. The average speed of the high-speed movement stage is higher than the average speed of the low-speed movement stage.

7. The control method according to claim 6, characterized in that, The high-speed motion phase is controlled to end at the end of the short arc burning time.

8. The control method according to claim 7, characterized in that, The average velocity v1 during the high-speed motion phase and the average velocity v2 during the low-speed motion phase satisfy the following condition: 2*v2≤v1.

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