Buffer, circuit breaker and circuit breaker opening speed control method

Abstract

This application relates to a buffer for adjusting the opening speed of a moving contact. The buffer includes a buffer cylinder and a piston assembly. The buffer cylinder includes an inner cylinder and an outer cylinder. The inner cylinder has a first cavity containing flowing liquid. The inner cylinder is disposed within the outer cylinder, and a receiving space is formed between the inner and outer cylinders. The inner wall of the inner cylinder has multiple flow holes communicating with the receiving space along the opening direction, which extends from the bottom to the top of the inner cylinder. The piston assembly is movably disposed within the first cavity along the opening direction and is connected to the moving contact. The piston assembly has a bearing surface for carrying the flowing liquid. As the flowing liquid moves along the opening direction with the piston assembly, it flows from the inner cylinder into the outer cylinder through the flow holes in a manner of first accelerating, then decelerating, then accelerating again, and finally decelerating. This ensures that the moving contact sequentially experiences an acceleration phase, a deceleration phase, an acceleration phase, and a deceleration phase, reducing the opening bounce phenomenon.

Description

Technical Field

[0001] This application relates to the field of high-voltage electrical equipment technology, and in particular to a buffer, a circuit breaker, and a method for controlling the opening speed of a circuit breaker. Background Art

[0002] Circuit breakers are an important component of power systems, functioning to isolate and disconnect circuits. They are typically installed in medium-voltage switchgear, double-layer switchgear, and fixed switchgear for controlling and protecting high-voltage electrical equipment. In actual operation, circuit breakers are prone to tripping, a phenomenon where the moving and stationary contacts repeatedly come into contact and separate during the tripping process. This tripping phenomenon can easily lead to damage to the circuit breaker.

[0003] Currently, to control the tripping bounce phenomenon in circuit breakers, a buffer is connected to the moving contact in the circuit breaker. The buffer controls the tripping speed of the moving contact to reduce tripping bounce. However, the buffer's effect in controlling tripping bounce is currently poor and fails to meet practical requirements. Summary of the Invention

[0004] Therefore, it is necessary to provide a buffer, circuit breaker, and circuit breaker tripping speed control method to address the current problem of circuit breaker tripping bounce.

[0005] A buffer for adjusting the opening speed of a moving contact, the buffer comprising a buffer cylinder and a piston assembly, the buffer cylinder comprising an inner cylinder and an outer cylinder, wherein:

[0006] The inner cylinder has a first cavity containing flowing liquid. The inner cylinder is disposed inside the outer cylinder, and a receiving space is formed between the inner cylinder and the outer cylinder. The inner wall of the inner cylinder has multiple flow holes communicating with the receiving space along the opening direction. The opening direction is the direction extending from the bottom end of the inner cylinder to the top end of the inner cylinder.

[0007] The piston assembly is movably disposed in the first cavity along the opening direction. The piston assembly is connected to the moving contact. The piston assembly has a bearing surface for bearing the flowing liquid. During the movement of the piston assembly along the opening direction, the flowing liquid moves synchronously with the piston assembly and eventually flows into the accommodating space.

[0008] The aforementioned buffer is connected to the moving contact via a piston assembly. During the opening process, the moving contact is driven by a driving component to move itself. The moving contact, through the piston assembly, drives the flowing liquid to move along the opening direction. In this process, the flowing liquid flows from the inner cylinder to the outer cylinder through the flow hole in a manner that first accelerates, then decelerates, then accelerates again, and finally decelerates. This causes the flowing liquid to react on the buffer resistance of the piston assembly and the moving contact, changing from decreasing to increasing, then decreasing again, and finally increasing. Thus, the moving contact sequentially experiences an acceleration phase, a deceleration phase, an acceleration phase, and a deceleration phase, ensuring that the opening speed of the moving contact meets the requirements of the standard opening speed characteristic curve. This improves the circuit breaker's ability to interrupt fault short circuits and prevent arc reignition, reduces opening bounce, and increases opening stability.

[0009] In one embodiment, the inner wall of the inner cylinder is divided into a first region, a second region, a third region, a fourth region, and a fifth region along the opening direction, and each region has the flow hole.

[0010] In one embodiment, the cross-sectional area of ​​the flow hole in the first region is smaller than the cross-sectional area of ​​the flow hole in the second region, and the cross-sectional area of ​​the flow hole in the second region is larger than the cross-sectional area of ​​the flow hole in the third region.

[0011] In one embodiment, the piston assembly includes a piston base and a piston rod disposed on the piston base, the bearing surface being located on the top surface of the piston base near the piston rod.

[0012] In one embodiment, the buffer further includes an adjustment mechanism, which includes a sliding bushing. The inner wall of the inner cylinder has an annular groove along its circumference. The sliding bushing is located in the annular groove and sleeved on the piston rod. The sliding bushing covers the flow hole in the fourth region. The sliding bushing is used to abut against the piston base when the piston base moves along the opening direction and move with the piston base until the flow hole in the fourth region is exposed. The cross-sectional area of ​​the flow hole in the fourth region is larger than the cross-sectional area of ​​the flow hole in the third region.

[0013] In one embodiment, the piston base has a guide hole that connects the bearing surface and the side of the piston base.

[0014] In one embodiment, the adjusting mechanism further includes an elastic element disposed within the annular groove, the elastic element being located on the side of the sliding bushing away from the bottom end of the inner cylinder.

[0015] In one embodiment, the cross-sectional area of ​​the flow hole in the fourth region is greater than the cross-sectional area of ​​the flow hole in the fifth region.

[0016] This application also provides a circuit breaker including a moving contact, a main shaft, and a buffer as described in any of the above embodiments, wherein one end of the main shaft is connected to the moving contact, and the other end of the main shaft is connected to the piston assembly in the buffer.

[0017] This application also provides a method for controlling the tripping speed of the circuit breaker described in the above embodiments, comprising the following steps:

[0018] The moving contact in the circuit breaker is driven to move so as to drive the flowing liquid to move in the opening direction through the piston assembly. The movement of the moving contact goes through an acceleration stage, a deceleration stage, an acceleration stage and a re-deceleration stage in sequence.

[0019] The above-mentioned circuit breaker tripping speed control method drives the moving contact in the circuit breaker to move, thereby driving the flowing liquid to move along the tripping direction through the piston assembly. The movement of the moving contact goes through a speed-up stage, a speed-down stage, a speed-up stage, and a speed-up stage again, so that the tripping speed of the moving contact meets the requirements of the standard tripping speed characteristic curve. This improves the circuit breaker's ability to interrupt fault short circuits and prevent arc reignition, reduces tripping bounce, and increases tripping stability. Attached Figure Description

[0020] Figure 1 A schematic diagram of the structure of the buffer provided in this application.

[0021] Figure 2 for Figure 1 A cross-sectional view of the inner cylinder.

[0022] Figure 3 A schematic diagram of the piston assembly provided in this application.

[0023] Figure 4 A cross-sectional view of the buffer when the piston assembly provided in this application is not moved.

[0024] Figure 5 A cross-sectional view of the buffer when the piston assembly provided in this application compresses the elastic element.

[0025] Figure 6 A flowchart illustrating the circuit breaker tripping speed control method provided in this application.

[0026] in:

[0027] 10. Buffer; a. Opening direction;

[0028] 100. Buffer cylinder; 110. Inner cylinder; 111. First cavity; 112. Flow hole; 113. Annular groove; 114. Protective wall; 120. Outer cylinder; 130. Accommodation space;

[0029] 200. Piston assembly; 210. Piston base; 211. Bearing surface; 212. Guide hole; 220. Piston rod;

[0030] 300. Flowing liquid;

[0031] 400. Adjustment mechanism; 410. Sliding bushing; 420. Elastic element. Detailed Implementation

[0032] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0033] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0034] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0035] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0036] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0037] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0038] See Figure 1 , Figure 2 and Figure 3 As shown, Figure 1 A schematic diagram of the structure of the buffer 10 in one embodiment of this application is shown. Figure 2 for Figure 1 A sectional view of the inner cylinder 110. Figure 3 This is a schematic diagram of the piston assembly 200 in one embodiment of this application. The buffer 10 provided in one embodiment of this application is used to adjust the opening speed of the moving contact, so that when the circuit breaker opens, the moving contact and stationary contact in the circuit breaker will not repeatedly contact and separate, thereby reducing the opening bounce phenomenon of the circuit breaker.

[0039] The buffer 10 includes a buffer cylinder 100 and a piston assembly 200. The buffer cylinder 100 includes an inner cylinder 110 and an outer cylinder 120. The inner cylinder 110 has a first cavity 111, which stores a flowing liquid 300. The inner cylinder 110 is disposed inside the outer cylinder 120, and a receiving space 130 is formed between the inner cylinder 110 and the outer cylinder 120. The inner wall of the inner cylinder 110 has a plurality of flow holes 112 that communicate with the receiving space 130 along the opening direction a. The opening direction a is the direction that extends from the bottom end of the inner cylinder 110 to the top end of the inner cylinder 110. In specific settings, the flowing liquid 300 can usually be set as hydraulic oil.

[0040] The piston assembly 200 is movably disposed within the first cavity 111 along the opening direction a. The piston assembly 200 is connected to the moving contact and has a bearing surface 211 for carrying the flowing liquid 300. Specifically, the piston assembly 200 includes a piston base 210 and a piston rod 220 disposed on the piston base 210. The piston base 210 has a bearing surface 211 for carrying the flowing liquid 300. It should be noted that when the circuit breaker opens, a driving component provides driving force to the moving contact, causing the moving contact to separate from the stationary contact. As the moving contact moves away from the stationary contact, it drives the piston assembly 200 to move along the opening direction a, thereby causing the flowing liquid 300 to move along the opening direction a.

[0041] During the movement of the piston assembly 200 along the opening direction a, the piston assembly 200 drives the flowing liquid 300 to move synchronously with the piston assembly 200 and eventually flow into the accommodating space 130. In a specific setting, the flowing liquid 300 is used to flow into the accommodating space 130 along the opening direction a through the flow hole 112 in the manner of first accelerating, then decelerating, then accelerating again and finally decelerating. That is, during the process of the flowing liquid 300 flowing from the inner cylinder 110 to the outer cylinder 120 along the opening direction a through the flow hole 112, it successively experiences the stages of acceleration, deceleration, re-acceleration and final deceleration. It should be noted that during the initial stage when the flowing liquid 300 rapidly flows from the inner cylinder 110 into the outer cylinder 120, the buffering resistance of the flowing liquid 300 acting on the piston assembly 200 and the moving contact decreases, and the moving contact experiences an acceleration phase. When the flowing liquid 300 decelerates and flows into the outer cylinder 120, the buffering resistance of the flowing liquid 300 acting on the piston assembly 200 and the moving contact increases, and the moving contact experiences a deceleration phase, which helps to completely extinguish the arc. Subsequently, the re-acceleration of the flowing liquid 300 corresponds to the moving contact experiencing another acceleration phase, which further shortens the opening time, improves the breaking performance, and also prevents arc reignition. Finally, the deceleration of the flowing liquid 300 corresponds to the moving contact experiencing another deceleration phase, achieving opening buffering, which can quickly absorb the remaining kinetic energy of the moving contact, achieve the technical effect of smooth deceleration, and minimize contact bounce.

[0042] The aforementioned buffer 10 is connected to the moving contact via the piston assembly 200. During the opening process, the moving contact is driven to move by the driving component. The moving contact will drive the flowing liquid 300 to move along the opening direction a via the piston assembly 200. During this process, the flowing liquid 300 flows from the inner cylinder 110 to the outer cylinder 120 through the flow hole 112 in a manner of first accelerating, then decelerating, then accelerating again, and finally decelerating. This causes the flowing liquid 300 to react on the piston assembly 200 and the buffer resistance of the moving contact, which changes from decreasing to increasing, then decreasing again, and finally increasing. Thus, the moving contact will sequentially experience the acceleration stage, deceleration stage, acceleration stage, and deceleration stage, so that the opening speed of the moving contact meets the requirements of the standard opening speed characteristic curve. This improves the circuit breaker's ability to break fault short circuits and prevent arc reignition, reduces the opening bounce phenomenon, and increases the breaking stability.

[0043] Combination Figure 4 As shown, Figure 4 A cross-sectional view of the buffer 10 when the piston assembly 200 is not moved is shown in one embodiment of this application. To facilitate the initial acceleration of the flowing liquid 300 from the inner cylinder 110 into the outer cylinder 120, in a preferred embodiment, the inner wall of the inner cylinder 110 is divided into five buffer zones along the opening direction a. These five buffer zones are designated as the first, second, third, fourth, and fifth zones, and each buffer zone has a flow hole 112. It should be noted that in the initial stage, i.e., the overtravel stage corresponding to the first zone, the piston assembly 200 is initially located at the bottom of the inner cylinder 110. The moving contact has a movement speed under the drive of the driving component, causing the flowing liquid 300 to have a flow speed. All the flow holes 112 in the five buffer zones participate in the flow, maximizing the flow area and flow speed, while minimizing the buffering resistance of the flowing liquid 300 on the moving contact, thus meeting the requirement of the moving contact accelerating at full speed.

[0044] It should be emphasized that the flow rate Q1 of the flow hole 112 on the side wall of the inner cylinder 110 can be derived from Bernoulli's equation. And record this equation as the first equation, where C d ΔP is the flow coefficient; ΔP is the pressure difference across the flow orifice 112. ρ is the sum of the cross-sectional areas of the flow holes 112 located in front of the piston base 210; ρ is the density of the flowing liquid 300, which is 850 kg / m³ when the flowing liquid 300 is type 12 aviation hydraulic oil. 3 The flow rate Q2 within the inner cylinder 110 can be obtained using the second equation, which is Q2 = A. e V e V e For the movement speed of piston assembly 200, A eLet Q1 be the area of ​​the bearing surface 211 on the piston base 210. Since the flow rate satisfies the fluid continuity condition, Q1 = Q2. Solving the first and second equations simultaneously yields the formula for the hydraulic resistance of the buffer 10: As can be seen from the hydraulic resistance formula of the buffer 10, the buffering performance is closely related to the cross-sectional area of ​​the flow hole 112 in front of the piston base 210. Therefore, the buffering characteristics of the buffer 10 can be adjusted by changing the cross-sectional area and position of the flow hole 112.

[0045] To facilitate the initial deceleration of the flowing liquid 300, specifically, the cross-sectional area of ​​the flow hole 112 in the first region is smaller than that in the second region, and the cross-sectional area of ​​the flow hole 112 in the second region is larger than that in the third region. It should be noted that the second region corresponds to the short-arc stage. Since the cross-sectional area of ​​the flow hole 112 in the first region is smaller than that in the second region—specifically, the cross-sectional area of ​​the flow hole 112 in the first region can be much smaller than that in the second region—the cross-sectional area of ​​the flow hole 112 in the second region can be the largest among the five buffer regions. When the piston assembly 200 moves to the second region, the flow hole 112 in the first region no longer participates in the flow of the flowing liquid 300. Compared to the piston assembly 200 in the first region, the buffering resistance increases, but because the cross-sectional area of ​​the flow hole 112 in the first region is small, the increase in buffering resistance is not significant. Therefore, the increased buffering resistance cannot counteract the tripping driving force.

[0046] The third region corresponds to the long arc stage. When the piston assembly 200 moves to the third region, the flow holes 112 in the first and second regions do not participate in the flow of the liquid 300, and the buffer resistance is significantly improved, thus beginning to resist the tripping driving force. The cross-sectional area of ​​the flow hole 112 in the second region can be much larger than that in the third region. When the piston assembly 200 moves to the third region, the cross-sectional area of ​​the flow hole 112 decreases sharply, and the buffer resistance of the buffer 10 increases dramatically, causing the tripping speed of the moving contact to decrease rapidly, ensuring sufficient arc extinguishing.

[0047] See again Figure 3 To facilitate the carrying of the flowing liquid 300, the piston assembly 200 specifically includes a piston base 210 and a piston rod 220 disposed on the piston base 210. The bearing surface 211 is located on the top surface of the piston base 210 near the piston rod 220. In a specific configuration, the piston base 210 and piston rod 220 are generally cylindrical, with the radius of the piston base 210 being larger than the radius of the piston rod 220. The cross-section of the piston assembly 200 is T-shaped.

[0048] To facilitate further acceleration of the flowing liquid 300, more specifically, the buffer 10 also includes an adjustment mechanism 400. The adjustment mechanism 400 includes a sliding sleeve 410. An annular groove 113 is formed on the inner wall of the inner cylinder 110 along its circumference. The sliding sleeve 410 is located in the annular groove 113 and fitted onto the piston rod 220. The sliding sleeve 410 blocks the flow hole 112 in the fourth region. The sliding sleeve 410 is used to abut against the piston base 210 when the piston base 210 moves along the opening direction a and moves with the piston base 210 until the flow hole 112 in the fourth region is exposed. The cross-sectional area of ​​the flow hole 112 in the fourth region is larger than that of the flow hole 112 in the third region. In a specific configuration, the sliding sleeve 410 is located on the bottom wall of the annular groove 113, and moves within the annular groove 113 along the opening direction a with the piston base 210.

[0049] It should be noted that the fourth region corresponds to the insulation recovery stage. During the process of the piston base 210 driving the sliding bushing 410 to move along the opening direction a, the flow hole 112 in the fourth region is opened, and the cross-sectional area of ​​the flow hole 112 in the fourth region is greater than that in the third region. At this time, the cross-sectional area of ​​the flow hole 112 participating in the flow of the liquid 300 increases again compared to the third region, reducing the buffer resistance that the buffer 10 can provide. The opening speed of the moving contact begins to increase, so as to further reduce the opening time and increase the opening speed, while preventing the arc from reigniting.

[0050] It should be emphasized that before the top surface of the piston base 210, i.e. the bearing surface 211, abuts against the bottom end of the sliding bushing 410, the side surface of the piston base 210 abuts against the inner wall of the inner cylinder 110. During the process of the piston base 210 driving the flowing liquid 300 to move along the opening direction a, the flowing liquid 300 flows from the bearing surface 211 into the flow hole 112.

[0051] When the piston base 210 abuts against the sliding sleeve 410 and drives the sliding sleeve 410 to move, the side of the piston base 210 separates from the inner wall of the inner cylinder 110, and there is a gap between the sliding sleeve 410 and the piston rod 220. The flowing liquid 300 is located on the bearing surface 211 of the inner hole of the sliding sleeve 410. In order for the flowing liquid 300 to flow more conveniently from the bearing surface 211 of the piston base 210 to the flow hole 112, the piston base 210 is further provided with a guide hole 212. The guide hole 212 connects the bearing surface 211 and the side of the piston base 210. The guide hole 212 is inclined, and one end of the guide hole 212 is located in the gap between the sliding sleeve 410 and the piston rod 220. The guide hole 212 is directly opposite to the flow hole 112 of the fourth region. Through the above arrangement, the flowing liquid 300 located in the sliding sleeve 410 flows into the flow hole 112 through the guide hole 212 and then into the outer cylinder 120. It should be noted that when the piston base 210 is not in contact with the sliding bushing 410, the flowing liquid 300 can also flow into the flow hole 112 through the guide hole 212.

[0052] Combination Figure 5 As shown, Figure 5 A cross-sectional view of the buffer 10 is shown in one embodiment of this application when the piston assembly 200 compresses the elastic member 420. To further improve the stability of the movement of the sliding bushing 410 driven by the piston base 210, the adjusting mechanism 400 also includes an elastic member 420. The elastic member 420 is disposed within the annular groove 113 and is located on the side of the sliding bushing 410 away from the bottom end of the inner cylinder 110. In a specific configuration, the elastic member 420 can be a spring. A protective wall 114 is connected to the top wall of the annular groove 113, forming a U-shaped protective space with the top wall and side wall of the annular groove 113. The elastic member 420 is located within this protective space. During operation, as the piston base 210 moves the sliding sleeve 410 along the opening direction a, the elastic element 420 is compressed, opening the flow hole 112 in the fourth region. The flowing liquid 300 flows through the guide hole 212 to the flow hole 112 in the fourth region. The cross-sectional area of ​​the flow hole 112 in the fourth region is larger than that in the third region, increasing the cross-sectional area of ​​the flow hole 112 involved in the flow when the piston assembly 200 is in the fourth region, thus increasing the opening speed of the moving contact. It should be noted that during the closing process, the piston assembly 200 moves in the opposite direction. The compressed spring provides a rebound force, pushing the sliding sleeve 410 in the opposite direction until it abuts against the bottom wall of the annular groove 113, thereby blocking the flow hole 112 in the fourth region.

[0053] To facilitate the final deceleration stage of the flowing liquid 300, more specifically, the cross-sectional area of ​​the flow hole 112 in the fourth region is larger than that in the fifth region. It should be noted that the fifth region corresponds to the final opening stage, which requires the opening speed to rapidly decrease to zero. When the piston assembly 200 is in the fifth region, the flow holes 112 in the first, second, third, and fourth regions do not participate in the flow. Furthermore, the cross-sectional area of ​​the flow hole 112 in the fifth region is smaller than that in the fourth region. This results in a rapid increase in the buffering resistance of the piston assembly 200 in the fifth region, enhancing the buffering effect on the moving contact, allowing the moving contact to rapidly decrease to zero.

[0054] It should be emphasized that, in order to make the flowing liquid 300 flow from the inner cylinder 110 into the outer cylinder 120 through the flow hole 112 in a manner of first accelerating, then decelerating, then accelerating again, and finally decelerating, in addition to setting the cross-sectional area of ​​the flow hole 112 in the five buffer areas along the opening direction a to first increase, then decrease, then increase again, and finally decrease, the opening speed control of the moving contact can also be strengthened by setting the number of flow holes 112 in the five buffer areas along the opening direction a to first increase, then decrease, then increase again, and finally decrease.

[0055] This application selects optimal values ​​for the five buffer zones divided on the side wall of the inner cylinder 110. The stroke of the first zone is divided into 0mm-17mm, the second zone into 17mm-45mm, the third zone into 45mm-90mm, the fourth zone into 90mm-100mm, and the fifth zone into 100mm-106mm. The optimal parameters for these five buffer zones are as follows:

[0056] In the first region, i.e., the over-travel stage: the cross-sectional area of ​​the flow orifice 112 in the first region is 5% of the area of ​​the bearing surface 211 of the piston base 210; there are 2 flow orifices 112 in the first region, and the total number of flow orifices 112 participating in the flow of liquid 300 in this stage is 14; the total area of ​​the flow orifices 112 participating in the flow in this stage is 71% of the area of ​​the bearing surface 211;

[0057] In the second region, i.e., the short-arc stage: the cross-sectional area of ​​the flow hole 112 in the second region is 56% of the area of ​​the bearing surface 211 of the piston base 210; there are 8 flow holes 112 in the second region, and the total number of flow holes 112 participating in the flow of liquid 300 in this stage is 12; the total area of ​​the flow holes 112 participating in the flow in this stage is 66% of the area of ​​the bearing surface 211.

[0058] In the third region, i.e., the long arc stage: the cross-sectional area of ​​the flow hole 112 in the third region is 6% of the area of ​​the bearing surface 211 of the piston base 210; there are 2 flow holes 112 in the third region, and the total number of flow holes 112 participating in the flow of liquid 300 in this stage is 4; the total area of ​​the flow holes 112 participating in the flow in this stage is 10% of the area of ​​the bearing surface 211.

[0059] In the fourth region, i.e., the insulation restoration stage: the cross-sectional area of ​​the flow hole 112 in the fourth region is 23% of the area of ​​the bearing surface 211 of the piston base 210; there are 4 flow holes 112 in the fourth region, and the total number of flow holes 112 participating in the flow of liquid 300 in this stage is 6; the total area of ​​the flow holes 112 participating in the flow in this stage is 27% of the area of ​​the bearing surface 211;

[0060] In the fifth region, i.e. the end of the tripping stage: the cross-sectional area of ​​the flow hole 112 in the fifth region is 4% of the area of ​​the bearing surface 211 of the piston base 210; there are 2 flow holes 112 in the fifth region, and the total number of flow holes 112 participating in the flow of liquid 300 in this stage is 2; the total area of ​​the flow holes 112 participating in the flow in this stage is 4% of the area of ​​the bearing surface 211.

[0061] This application also discloses a circuit breaker, which includes a moving contact, a main shaft, and a buffer 10 as described in any of the above embodiments. One end of the main shaft is connected to the moving contact, and the other end of the main shaft is connected to the piston assembly 200 in the buffer 10.

[0062] In the aforementioned circuit breaker, a piston assembly 200 is connected to the moving contact via a main shaft. During the opening process, the moving contact is driven by a driving component to move. The moving contact, through the piston assembly 200, drives the flowing liquid 300 to move along the opening direction a. During this process, the flowing liquid 300 flows from the inner cylinder 110 to the outer cylinder 120 through the flow hole 112 in a manner that first accelerates, then decelerates, then accelerates again, and finally decelerates. This causes the flowing liquid 300 to react on the buffer resistance of the piston assembly 200 and the moving contact, changing from decreasing to increasing, then decreasing again, and finally increasing. Thus, the moving contact sequentially experiences an acceleration phase, a deceleration phase, an acceleration phase, and a deceleration phase, ensuring that the opening speed of the moving contact meets the requirements of the standard opening speed characteristic curve. This improves the circuit breaker's ability to interrupt faults and short circuits and prevent arc reignition, reduces opening bounce, and increases opening stability.

[0063] Combination Figure 6 As shown, Figure 6This application provides a flowchart of a circuit breaker tripping speed control method. The application also provides a tripping speed control method based on the above-mentioned circuit breaker, comprising the following steps: Step S1, driving the moving contact in the circuit breaker to move so as to drive the flowing liquid 300 to move along the tripping direction a via the piston assembly 200. The movement of the moving contact sequentially undergoes an acceleration stage, a deceleration stage, an acceleration stage, and a re-deceleration stage. It should be noted that during the process of the moving contact driving the flowing liquid 300 along the tripping direction a via the piston assembly 200, the flowing liquid 300 flows into the receiving space 130 through the flow hole 112 along the tripping direction a in a manner of first accelerating, then decelerating, then accelerating again, and finally decelerating, so that the moving contact sequentially undergoes the acceleration stage, deceleration stage, acceleration stage, and re-deceleration stage. It is easy to understand that when the flowing liquid 300 flows into the accommodating space 130 in a manner of first accelerating, then decelerating, then accelerating again, and finally decelerating, the buffering resistance of the flowing liquid 300 acting on the piston assembly 200 and the moving contact changes in a manner of first decreasing, then increasing, then decreasing again, and finally increasing. Therefore, the moving contact will successively go through the acceleration stage, the deceleration stage, the acceleration stage again, and the final deceleration stage, thus achieving the opening buffer and minimizing the contact bounce phenomenon.

[0064] The above-mentioned circuit breaker tripping speed control method drives the moving contact in the circuit breaker to move, thereby driving the flowing liquid 300 to move along the tripping direction a through the piston assembly 200. The movement of the moving contact goes through a speed-up stage, a speed-down stage, a speed-up stage, and a speed-up stage again, so that the tripping speed of the moving contact meets the requirements of the standard tripping speed characteristic curve. This improves the circuit breaker's ability to interrupt fault short circuits and prevent arc reignition, reduces tripping bounce, and increases tripping stability.

[0065] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0066] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A buffer for adjusting the opening speed of the moving contact, characterized in that, The buffer includes a buffer cylinder and a piston assembly, wherein the buffer cylinder includes an inner cylinder and an outer cylinder, wherein: The inner cylinder has a first cavity containing flowing liquid. The inner cylinder is disposed inside the outer cylinder, and an accommodating space is formed between the inner cylinder and the outer cylinder. The inner wall of the inner cylinder is divided into a first region, a second region, a third region, a fourth region, and a fifth region along the opening direction. Each region has a flow hole. The cross-sectional area of ​​the flow hole in the first region is smaller than that in the second region, the cross-sectional area of ​​the flow hole in the second region is larger than that in the third region, the cross-sectional area of ​​the flow hole in the fourth region is larger than that in the third region, and the cross-sectional area of ​​the flow hole in the fourth region is larger than that in the fifth region. The inner wall of the inner cylinder has multiple flow holes communicating with the accommodating space along the opening direction, which is the direction extending from the bottom end of the inner cylinder to the top end of the inner cylinder. The piston assembly is movably disposed in the first cavity along the opening direction. The piston assembly is connected to the moving contact. The piston assembly has a bearing surface for bearing the flowing liquid. During the movement of the piston assembly along the opening direction, the flowing liquid is driven to flow into the accommodating space through the flow hole in the opening direction in a manner of first accelerating, then decelerating, then accelerating again and finally decelerating. The piston assembly includes a piston base and a piston rod disposed on the piston base, wherein the bearing surface is located on the top surface of the piston base near the piston rod; The buffer also includes an adjustment mechanism, which includes a sliding bushing. The inner wall of the inner cylinder has an annular groove along its circumference. The sliding bushing is located in the annular groove and sleeved on the piston rod. The sliding bushing covers the flow hole in the fourth region. The sliding bushing is used to abut against the piston base when the piston base moves along the opening direction and move with the piston base to expose the flow hole in the fourth region.

2. The buffer according to claim 1, characterized in that, The piston base has a guide hole that connects the bearing surface and the side of the piston base.

3. The buffer according to claim 1, characterized in that, The adjusting mechanism also includes an elastic element disposed within the annular groove, the elastic element being located on the side of the sliding bushing away from the bottom end of the inner cylinder.

4. A circuit breaker, characterized in that, It includes a moving contact, a main shaft, and a buffer as described in any one of claims 1-3, wherein one end of the main shaft is connected to the moving contact, and the other end of the main shaft is connected to the piston assembly in the buffer.

5. A method for controlling the tripping speed of a circuit breaker according to claim 4, characterized in that, Includes the following steps: The moving contact in the circuit breaker is driven to move so as to drive the flowing liquid to move in the opening direction through the piston assembly. The movement of the moving contact goes through an acceleration stage, a deceleration stage, an acceleration stage and a re-deceleration stage in sequence.

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