Arc striking system of circuit breaker and circuit breaker

Abstract

The utility model relates to a circuit breaker, in particular to an arc striking system of a circuit breaker and the circuit breaker, and the circuit breaker comprises a shell, a static contact, a moving contact and an arc extinguish chamber, the static contact is fixedly assembled in the shell, and the moving contact is rotationally assembled in the shell; the arc extinguish chamber is arranged along the motion path of the moving contact. The arc striking system comprises an equipotential grid plate and a limiting structure; the equipotential grid plate is arranged at the tail end of the motion path of the moving contact and is arranged at the tail end of the arc extinguish chamber; the limiting structure is arranged on the shell and is arranged on a motion path of the moving contact; in an opening state, the moving contact is located at an opening position; the equipotential grid sheet abuts against one end of the moving contact, and the limiting structure abuts against the rod portion of the moving contact. Compared with the prior art, the utility model solves the problems in the prior art that the arc striking effect of breaking fault arc is poor and the moving contact is easy to deform due to impact when the opening distance and the size of the arc extinguish chamber are relatively large. According to the scheme, the arc striking effect is enhanced and the possibility of impact deformation of the moving tail end of the moving contact is weakened through the equipotential grid plates.

Description

Technical Field

[0001] This utility model relates to a circuit breaker, specifically to an arc-starting system for a circuit breaker and a circuit breaker itself. Background Technology

[0002] In high-voltage operating environments, when a fault current occurs in the power system, the molded case circuit breaker needs to reserve a sufficiently large opening distance between the stationary and moving contacts and a sufficient number of arc-extinguishing chambers and arc-extinguishing grids to quickly disconnect and extinguish the fault arc.

[0003] However, increasing the opening distance also increases the height of the arc-extinguishing chamber and the length of the moving contact. Consequently, the arc-extinguishing grid at the upper part of the arc-extinguishing chamber, located at the end of the moving contact's movement path, is further away from the contact points of the moving and stationary contacts. This makes it difficult for the arc to enter the arc-extinguishing grid at the upper end of the arc-extinguishing chamber during arc breaking, resulting in low utilization efficiency of these grids, failing to effectively increase the arc voltage, and ultimately affecting the arc extinguishing effect. Furthermore, increasing the length of the moving contact increases the distance from the center of rotation of the moving contact at its end within the arc-extinguishing chamber (the contact end). During the circuit breaker's opening movement, the high linear velocity at the end of the moving contact results in greater impact, making this end section prone to structural deformation. This leads to poor contact between the moving and stationary contacts after the circuit breaker closes, ultimately affecting the circuit breaker's operation.

[0004] In existing high-voltage molded case circuit breakers, arc-initiating structures or equipotential structures are added to the arc-extinguishing chamber to encourage the arc to enter the upper arc-extinguishing grid plates. For example, CN118448229A discloses an arc-initiating system and circuit breaker. Through the coordination of the stationary contact arc-initiating angle, the U-shaped arc-initiating plate, the moving contact arc-initiating angle, and the moving contact equipotential arc-initiating plate, the overall arc movement is accelerated, preventing arc erosion of the contact material and improving the circuit breaker's current-limiting and breaking capacity. However, when the distance between the moving and stationary contacts and the height of the arc-extinguishing chamber are both large (the distance is close to or greater than half the circuit breaker height, which can be considered large), the arc-initiating effect achievable when breaking fault arcs is not ideal, and it easily exacerbates the risk of deformation of the moving contact due to large-area impact. Utility Model Content

[0005] The purpose of this invention is to provide an arc-ignition system and a circuit breaker to solve at least one of the aforementioned problems. This addresses the shortcomings of existing technologies where, with large distances between moving and stationary contacts and significant arc-extinguishing chamber height, the arc-ignition effect during fault arc interruption is unsatisfactory, and the risk of deformation of the moving contact due to large-area impact is easily increased. This solution enhances the utilization rate of the end arc-extinguishing grids in the arc-extinguishing chamber by incorporating equipotential bonding plates, thereby improving the arc-extinguishing effect. Simultaneously, the combined use of equipotential bonding plates and a limiting structure achieves a buffering effect, reducing the possibility of deformation of the moving contact's moving end due to impact.

[0006] The objective of this utility model is achieved through the following technical solution:

[0007] The first aspect of this utility model discloses an arc-ignition system for a circuit breaker, wherein the circuit breaker includes a housing, a stationary contact, a moving contact, and an arc-extinguishing chamber; the stationary contact is fixedly assembled inside the housing, and the moving contact is rotatably assembled inside the housing; the arc-extinguishing chamber is arranged along the movement path of the moving contact.

[0008] The arc-starting system includes an equipotential grid and a limiting structure;

[0009] The equipotential grid is disposed at the end of the movement path of the moving contact, and the equipotential grid is disposed at the end of the arc-extinguishing chamber;

[0010] The limiting structure is disposed on the housing and is disposed on the movement path of the moving contact;

[0011] When the circuit is closed, the stationary contact of the stationary contact and the moving contact of the moving contact are in contact.

[0012] In the open position, the stationary contact of the stationary contact is separated from the moving contact of the moving contact, and the moving contact is in the open position; the equipotential grid abuts against the end of the moving contact where the moving contact is located so that the potential of the equipotential grid and the moving contact are equal, and the limiting structure abuts against the rod of the moving contact.

[0013] Preferably, the arc-extinguishing chamber includes an arc-extinguishing grid assembly;

[0014] The arc-extinguishing grid assembly includes a plurality of arc-extinguishing grids arranged at intervals along the movement path of the moving contact;

[0015] The equipotential grid and the arc-extinguishing grid group are spaced apart at the very end.

[0016] The equipotential grids, which are spaced apart from the arc-extinguishing grid group, also play a certain role in arc initiation. Furthermore, the equipotential grids are in contact with the moving contact at the open position, so that the potential between the equipotential grids and the moving contact is equal. This allows the remaining part of the arc on the moving contact to be quickly and effectively transferred and guided to the arc-extinguishing grid group at the end of the arc-extinguishing chamber for arc extinguishing.

[0017] Preferably, the arc-extinguishing chamber further includes a first insulating component and a second insulating component;

[0018] The arc-extinguishing grid plate has a U-shaped structure, with both ends of the arc-extinguishing grid plate extending to both sides of the movement path of the moving contact;

[0019] The first insulating element and the second insulating element are respectively disposed on both sides of the movement path of the moving contact, and the first insulating element and the second insulating element are respectively disposed between the moving contact and the arc extinguishing grid.

[0020] The U-shaped arc-extinguishing grid fully utilizes the internal space of the circuit breaker to meet the arc-extinguishing distance of the arc-extinguishing chamber within a relatively small circuit breaker structure, thereby ensuring that the arc can be effectively extinguished. At the same time, the insulating parts located at both ends of the U-shape and between the arc-extinguishing grid and the moving contact further block the arc in the arc-extinguishing chamber from the moving contact, avoiding the impact of the arc on the moving contact.

[0021] Preferably, the equipotential grid includes a grid and an extension structure;

[0022] The grid plate has a U-shaped structure, and the extension structure is connected to the grid plate;

[0023] The extended structure and the plane where the grid plate is located are set at an angle, and the equipotential grid plate abuts against one end of the moving contact where the moving contact point is set through the extended structure.

[0024] Preferably, the extension structure is disposed on the side of the grid plate facing the moving contact, and the end of the extension structure abuts against the rod portion of the moving contact.

[0025] Preferably, the extension structure is connected to the middle of the grid plate, and the extension structure passes through the interior of the arc-extinguishing chamber to abut against the moving contact.

[0026] Preferably, the surface of the equipotential grid that abuts against the moving contact is the contact area, and the surface of the limiting structure that abuts against the moving contact is the limiting area;

[0027] The contact area is located between the limiting area and the moving contact of the moving contact.

[0028] When the moving contact rotates, its end and the rod have the same angular velocity, but the linear velocity of the end is significantly greater than the angular velocity. Therefore, in this solution, the design of the contact area and the limiting area respectively allows the end and the rod to collide and buffer, dispersing the motion impact on the moving contact during opening. Moreover, under normal circumstances, the equipotential grid should have a certain amount of movable space or flexibility compared to the limiting structure. Therefore, when phases collide, the equipotential grid can also absorb energy from the moving contact to dissipate kinetic energy, further reducing the possibility of collision deformation.

[0029] Preferably, the surface of the equipotential grid that abuts against the moving contact is the contact area, and the surface of the limiting structure that abuts against the moving contact is the limiting area;

[0030] The area of ​​the contact area is smaller than the area of ​​the limiting area.

[0031] When the moving contact rotates, its end and the rod have the same angular velocity, but the linear velocity of the end is significantly greater than the angular velocity. Therefore, in this design, the end and the rod collide and are buffered separately through the design of the contact area and the limiting area, which disperses the motion impact on the moving contact when the circuit breaker is opened. In addition, the limiting structure has a larger collision area, which can effectively disperse the impact force on the moving contact, weaken the motion impact deformation of the moving end of the moving contact, and ensure that the moving contact and the stationary contact still have good contact after the circuit breaker is closed.

[0032] Preferably, the housing includes a base and an outer shell;

[0033] The base and the outer shell are assembled to form an inner cavity, in which the stationary contact, the moving contact, and the arc-extinguishing chamber are all disposed;

[0034] The stationary contact is fixedly mounted on the base;

[0035] The moving contact is rotatably mounted on the base;

[0036] The arc-extinguishing chamber is fixedly assembled on the base;

[0037] The limiting structure is provided on the outer shell.

[0038] The second aspect of this utility model discloses a circuit breaker, including the arc-starting system as described above.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] This invention provides an arc-ignition system for molded case circuit breakers under high-voltage operating requirements. While effectively interrupting fault arcs, it ensures effective contact between the moving and stationary contacts after reclosing, guaranteeing stable operation of the circuit breaker. When the moving contact rotates to the open position, a portion of the arc generated by the circuit breaker interrupting a fault circuit is effectively transferred to the upper (end) part of the arc-extinguishing chamber, fully utilizing the arc-extinguishing grid at the upper end of the chamber to increase the arc voltage. Furthermore, the local buffer structure (an extension of the equipotential grid) added to this arc-ignition system, in conjunction with the limiting structure of the circuit breaker housing, disperses the impact of movement on the moving end of the moving contact located within the arc-extinguishing chamber, reducing deformation of that part of the moving contact.

[0041] (1) No additional conductor is required on the equipotential grid to always maintain connection with the moving contact. The structure is simple, easy to install, and saves on manufacturing process.

[0042] (2) The equipotential grid not only serves to achieve equipotential with the moving contact, but also provides motion buffer for the moving contact.

[0043] (3) A limiting structure for the opening position of the moving contact has been added to disperse the impact of the opening movement and reduce the deformation of the moving end part of the moving contact. Attached Figure Description

[0044] Figure 1 This is a schematic cross-sectional view of the circuit breaker.

[0045] Figure 2 This is a schematic diagram of the internal structure of a circuit breaker;

[0046] Figure 3 This is a cross-sectional view of the internal structure of the circuit breaker.

[0047] Figure 4 This is a schematic diagram of the structure of the isoelectric arc grid.

[0048] Figure 5 This is a schematic diagram of the outer shell structure;

[0049] In the figure: base 1; outer shell 2, limiting structure 21, limiting area 211; stationary contact 3; stationary contact 31; moving contact 4, moving end 41, rotation center 42; moving contact 43; rod 44; arc extinguishing chamber 5, arc extinguishing grid assembly 51, first insulating component 52; second insulating component 53; equipotential grid 6, extension structure 61, contact area 611. Detailed Implementation

[0050] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0051] Example 1

[0052] An arc-starting system for a circuit breaker, such as Figure 1-5 As shown, the circuit breaker includes a housing, a stationary contact 3, a moving contact 4, and an arc-extinguishing chamber 5; the stationary contact 3 is fixedly assembled inside the housing, and the moving contact 4 is rotatably assembled inside the housing; the arc-extinguishing chamber 5 is arranged along the movement path of the moving contact 4.

[0053] The arc-starting system includes an equipotential grid plate 6 and a limiting structure 21;

[0054] The equipotential grid 6 is disposed at the end of the movement path of the moving contact 4, and the equipotential grid 6 is disposed at the end of the arc-extinguishing chamber 5;

[0055] The limiting structure 21 is disposed on the housing and is disposed on the movement path of the moving contact 4;

[0056] When the circuit is closed, the stationary contact 31 of the stationary contact 3 abuts against the moving contact 43 of the moving contact 4;

[0057] In the open position, the stationary contact 31 of the stationary contact 3 is separated from the moving contact 43 of the moving contact 4, and the moving contact 4 is in the open position; the equipotential grid 6 abuts against the end of the moving contact 4 where the moving contact 43 is provided, so that the potential of the equipotential grid 6 and the moving contact 4 are equal, and the limiting structure 21 abuts against the rod 44 of the moving contact 4.

[0058] More specifically, in this embodiment:

[0059] An arc-initiating system is installed inside a circuit breaker. Its main purpose is to provide an arc-initiating system for molded case circuit breakers under high-voltage operating requirements. While effectively interrupting fault arcs, it can ensure effective contact between the moving contact 4 and the stationary contact 3 after reclosing, thus ensuring the stable operation of the circuit breaker.

[0060] The circuit breaker includes: a base 1, a housing 2, a stationary contact 3, a moving contact 4, and an arc-extinguishing chamber 5. The arc-ignition system is composed of an equipotential grid 6 and a limiting structure 21.

[0061] like Figure 1-3In the circuit breaker shown, the stationary contact 3 is fixedly installed in the base 1, and the moving contact 4 is rotatably connected to the base 1 through a corresponding transmission mechanism in the circuit breaker (the transmission mechanism designed in the existing circuit breaker can be used; this scheme does not improve or change the transmission mechanism and its connection relationship with the moving contact 4). Under the action of the transmission mechanism, the moving contact 4 can rotate around the rotation center 42 at the right end. The arc-extinguishing chamber 5 is located on the side of the moving end 41 (set at one end of the moving contact 43) at the left end of the moving contact 4, above the stationary contact 3, and the arc-extinguishing chamber 5 is set along the movement path of the moving end 41. The arc-extinguishing chamber 5 contains an arc-extinguishing grid plate group 51 arranged along the movement path of the moving contact 4 to extinguish the arc generated by the interruption of the fault circuit in the circuit breaker, as well as a first insulating element 52 and a second insulating element 53. Specifically, the arc-extinguishing grid plate group 51 is composed of several arc-extinguishing grid plates with U-shaped structures arranged at intervals. The middle of the arc-extinguishing grid plate can accommodate the moving end 41 of the moving contact 4. The two ends of the U-shaped structure extend to both sides of the moving contact 4 to provide as much arc-extinguishing distance and arc-extinguishing space as possible. At the same time, in order to avoid the arc introduced between the arc-extinguishing grid plates from damaging and affecting the moving contact 4, the first insulating element 52 and the second insulating element 53 are respectively arranged on both sides of the moving contact 4 and between the moving contact 4 and the arc-extinguishing grid plate. The two can be such as insulating baffles or insulating blocks to achieve insulation between the two sides of the moving contact 4 and the arc-extinguishing chamber 5.

[0062] The equipotential bonding grid 6 is fixedly mounted on the upper (end) end of the arc-extinguishing chamber 5, and is spaced apart from the last arc-extinguishing grid in the arc-extinguishing grid group 51. The equipotential bonding grid 6 is also located above the moving contact 4, and its extension structure 61 passes through the arc-extinguishing chamber 5 and contacts the moving contact 4 when it is rotated to the open position, thereby forming an equipotential bonding. Specifically, the equipotential bonding grid 6, as shown... Figure 4 As shown, the circuit includes a grid plate and an extension structure 61. The grid plate is also U-shaped, and the extension structure 61 extends from the central notch and forms an angle with the plane of the grid plate (the end of the extension structure 61 abuts against the end of the rod 44 of the moving contact 4 near the moving contact 43). The grid plate can work together with the arc-extinguishing grid plate group 51 to achieve arc initiation and arc extinguishing. The extension structure 61 passes through the U-shaped notch of the arc-extinguishing grid plate group 51 and abuts against the moving contact 4 in the open position. Furthermore, part of the arc generated when the circuit breaker disconnects the fault circuit can be directly transferred to the upper part of the arc-extinguishing grid plate group 51, which is arranged at intervals with the equipotential grid plate 6, for arc segmentation after the moving contact 4 turns to the open position, thereby making full use of the arc-extinguishing chamber 5.

[0063] like Figure 2-3As shown, when the opening distance between the moving contact 4 and the stationary contact 3 and the height of the arc-extinguishing chamber 5 are both large, a considerable portion of the moving contact 4 is located inside the arc-extinguishing chamber 5. Consequently, the moving end 41 of the moving contact 4 located inside the arc-extinguishing chamber 5 is far from the rotation center 42. Since the circuit breaker requires the moving contact 4 to have an extremely fast opening speed to lengthen the arc in a short time when opening, this results in the linear velocity of the moving end 41 being faster than the rest of the moving contact 4 during the opening process. Consequently, the impact of the movement after it rotates to the opening position and comes into contact with the structure in the circuit breaker used to limit the movement of the moving contact 4 is also relatively large.

[0064] In this solution, in addition to the equipotential grid 6 corresponding to the moving end 41, a limiting structure 21 is also provided at the position corresponding to the rod portion 44 of the moving contact 4. Specifically, the limiting structure 21 is the part of the outer shell 2 extending toward the moving contact 4, and it is located near the end of the arc-extinguishing chamber 5. Figure 1 , 5 As shown, when the moving contact 4 is in the open position, the limiting structure 21 abuts against the rod portion 44 of the moving contact 4. The surface of the extension structure 61 that abuts against the moving contact 4 is designated as the contact area 611, which contacts the moving end 41 when the moving contact 4 is in the open position; the surface of the limiting structure 21 that abuts against the moving contact 4 is designated as the limiting area 211, which abuts against the rod portion 44 of the moving contact 4 when the moving contact 4 is in the open position. Furthermore, the area of ​​the contact area 611 is relatively smaller than that of the limiting area 211, and the contact area 611 is closer to the end of the movement trajectory of the moving contact 4 in the arc-extinguishing chamber 5 (i.e., the contact area 611 is close to the moving end 41 with the fastest linear velocity when the moving contact 4 is opened). Therefore, this scheme uses the equipotential grid plate 6 to achieve collision buffering for the moving end 41, and in conjunction with the limiting structure 21 in the circuit breaker to limit the moving contact 4 over a wide range, disperses the impact of the opening movement on the moving contact 4, and reduces the possible deformation of the moving end 41 when the moving contact 4 is opened.

[0065] Working principle:

[0066] When a fault current occurs in the power system, the circuit breaker trips and disconnects the circuit. The moving contact 4 separates from the stationary contact 3, and a fault arc is generated at the contact point of the moving contact 4 and the stationary contact 3 (the contact point of the moving contact 43 and the stationary contact 31). Part of the arc enters the arc-extinguishing chamber 5 from below at the stationary contact 3, while part of the arc is elongated as the moving contact 4 rotates and enters the arc-extinguishing grid plate group 51 of the arc-extinguishing chamber 5 during the rotation of the moving contact 4. When the moving contact 4 rotates to the open position, the moving end 41 located in the arc-extinguishing chamber 5 collides and contacts with the extension structure 61 on the equipotential grid plate 6. The equipotential grid plate 6 and the moving contact 4 then form an equipotential relationship, and the contact range between the two is limited to the contact area 611. At this time, the remaining part of the arc on the moving contact 4 in the open position can be more easily transferred to the upper part of the arc-extinguishing grid plate group 51 through the equipotential grid plate 6, which has the same potential as the moving contact 4, and enter the arc-extinguishing grid plates arranged at intervals with the equipotential grid plate 6. This allows the arc-extinguishing grid plates in the upper part of the arc-extinguishing grid plate group 51 to play their role. In this way, all the arc-extinguishing grid plates in the arc-extinguishing grid plate group 51 can be used to divide the fault arc, thereby effectively increasing the arc voltage and improving the arc extinguishing effect.

[0067] When the moving contact 4 inside the circuit breaker rotates to the open position, it collides with the extension structure 61 and the limiting structure 21 respectively, and both bear the impact of the opening movement of the moving contact 4. Among them, the contact area 611 where the extension structure 61 contacts the moving contact 4 is smaller than the limiting area 211 where the limiting structure 21 contacts the moving contact 4, that is, the impact surface of the equipotential grid 6 on the opening movement of the moving contact 4 is relatively smaller; and the collision position of the extension structure 61 with the moving contact 4 is closer to the end of the movement trajectory of the moving contact 4 in the arc-extinguishing chamber 5, that is, closer to the movement end 41, compared to the collision position of the limiting structure 21 with the moving contact 4. Therefore, the equipotential grid 6 is more likely to buffer the collision of the movement end 41, which is located in the arc-extinguishing chamber 5 with the fastest movement speed and is most prone to deformation. By utilizing the buffering effect of the equipotential grid plate 6 on the moving contact 4, and in conjunction with the limiting structure 21, the impact of the opening movement on the moving contact 4 can be effectively dispersed, the movement impact deformation of the moving end 41 can be weakened, and the moving contact 4 can maintain good contact with the stationary contact 3 after the circuit breaker is closed again.

[0068] In summary, the main purpose of this solution is to provide an arc-ignition system for molded case circuit breakers under high-voltage operating requirements. This system effectively interrupts fault arcs while ensuring effective contact between the moving contact 4 and the stationary contact 3 after reclosing, thereby guaranteeing stable operation of the circuit breaker. Part of the arc generated when the circuit breaker interrupts a fault circuit is effectively transferred to the upper part of the arc-extinguishing chamber 5 via the equipotential bonding plate 6 when the moving contact 4 rotates to the open position. This fully utilizes the arc-extinguishing bonding plate in the upper part of the arc-extinguishing chamber 5, increasing the arc voltage. Furthermore, the limiting structure added inside the casing 2 by this arc-ignition system effectively disperses the impact on the moving end 41 located within the arc-extinguishing chamber 5, reducing deformation of that part of the moving contact 4.

[0069] The above description of the embodiments is provided to enable those skilled in the art to understand and use the utility model. It will be apparent to those skilled in the art that various modifications can be easily made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present utility model is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present utility model without departing from its scope should be within the protection scope of the present utility model.

Claims

1. An arc-ignition system for a circuit breaker, the circuit breaker comprising a housing, a stationary contact (3), a moving contact (4), and an arc-extinguishing chamber (5); the stationary contact (3) is fixedly mounted inside the housing, and the moving contact (4) is rotatably mounted inside the housing; the arc-extinguishing chamber (5) is arranged along the movement path of the moving contact (4); Its features are, The arc-starting system includes an equipotential grid (6) and a limiting structure (21); The equipotential grid plate (6) is disposed at the end of the movement path of the moving contact (4), and the equipotential grid plate (6) is disposed at the end of the arc-extinguishing chamber (5); The limiting structure (21) is provided on the housing and is located on the movement path of the moving contact (4); In the closed state, the stationary contact (31) of the stationary contact (3) abuts against the moving contact (43) of the moving contact (4); In the open position, the stationary contact (31) of the stationary contact (3) is separated from the moving contact (43) of the moving contact (4), and the moving contact (4) is in the open position; the equipotential grid (6) abuts against the end of the moving contact (4) where the moving contact (43) is located, so that the potential of the equipotential grid (6) and the moving contact (4) are equal, and the limiting structure (21) abuts against the rod (44) of the moving contact (4).

2. The arc-starting system for a circuit breaker according to claim 1, characterized in that, The arc-extinguishing chamber (5) includes an arc-extinguishing grid assembly (51); The arc-extinguishing grid assembly (51) includes a plurality of arc-extinguishing grids arranged at intervals along the movement path of the moving contact (4); The equipotential grid (6) and the arc-extinguishing grid at the very end of the arc-extinguishing grid group (51) are spaced apart.

3. The arc-starting system for a circuit breaker according to claim 2, characterized in that, The arc-extinguishing chamber (5) further includes a first insulating element (52) and a second insulating element (53); The arc-extinguishing grid plate has a U-shaped structure, with both ends of the arc-extinguishing grid plate extending to both sides of the movement path of the moving contact (4); The first insulating element (52) and the second insulating element (53) are respectively disposed on both sides of the movement path of the moving contact (4), and the first insulating element (52) and the second insulating element (53) are respectively disposed between the moving contact (4) and the arc extinguishing grid.

4. The arc-starting system for a circuit breaker according to claim 1, characterized in that, The equipotential grid (6) includes a grid and an extension structure (61); The grid plate has a U-shaped structure, and the extension structure (61) is connected to the grid plate; The extension structure (61) is set at an angle with the plane where the grid plate is located, and the equipotential grid plate (6) abuts against one end of the moving contact (43) through the extension structure (61).

5. The arc-starting system for a circuit breaker according to claim 4, characterized in that, The extension structure (61) is disposed on the side of the grid plate facing the moving contact (4), and the end of the extension structure (61) abuts against the rod portion (44) of the moving contact (4).

6. The arc-starting system for a circuit breaker according to claim 5, characterized in that, The extension structure (61) is connected to the middle of the grid plate, and the extension structure (61) passes through the inside of the arc-extinguishing chamber (5) to abut against the moving contact (4).

7. The arc-starting system for a circuit breaker according to claim 1, characterized in that, The surface of the equipotential grid (6) that abuts against the moving contact (4) is the contact area (611), and the surface of the limiting structure (21) that abuts against the moving contact (4) is the limiting area (211). The contact area (611) is located between the limiting area (211) and the moving contact (43) of the moving contact (4).

8. The arc-starting system for a circuit breaker according to claim 1, characterized in that, The surface of the equipotential grid (6) that abuts against the moving contact (4) is the contact area (611), and the surface of the limiting structure (21) that abuts against the moving contact (4) is the limiting area (211). The area of ​​the contact area (611) is smaller than the area of ​​the limiting area (211).

9. The arc-starting system for a circuit breaker according to claim 1, characterized in that, The housing includes a base (1) and an outer shell (2); The base (1) and the outer shell (2) are assembled to form an inner cavity, and the stationary contact (3), the moving contact (4) and the arc-extinguishing chamber (5) are all disposed in the inner cavity; The stationary contact (3) is fixedly assembled on the base (1); The moving contact (4) is rotatably mounted on the base (1); The arc-extinguishing chamber (5) is fixedly assembled on the base (1); The limiting structure (21) is provided on the outer shell (2).

10. A circuit breaker, characterized in that, Including the arc-starting system as described in any one of claims 1-9.

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