Auxiliary contact structure and device for measuring arc parameters between circuit breaker fractures

Abstract

The invention relates to the technical field of circuit breaker arc measurement, in particular to an auxiliary contact structure circuit breaker fracture arc parameter measuring device which comprises a boss arranged on the inner wall of an air cylinder of a circuit breaker and an auxiliary contact assembly arranged in the air cylinder. In the current breaking process of the circuit breaker, the arc root part on one side of the hollow arc contact is stabilized at the end part of the auxiliary contact assembly, the arc root part moving area is reduced, and the shooting of the arc form and the measurement of related parameters are facilitated; the boss is matched with the piston disc of the auxiliary contact assembly, the auxiliary contact is driven through the pressure difference of the two sides of the piston disc, high-pressure air in the air cylinder enters the nozzle through the gap between the boss and the piston disc, high-speed air blowing is formed, the arc temperature is reduced, and current on-off is completed. The movement process of the whole auxiliary contact assembly is almost not affected by arc heat production, and the problems that in an existing auxiliary contact structure, due to the heating effect of an arc, spring driving is blocked, and the installation difficulty of an auxiliary contact is large are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit breaker arc measurement, specifically to an auxiliary contact structure and a circuit breaker inter-break arc parameter measuring device, in particular to an auxiliary contact structure and a circuit breaker inter-break arc parameter measuring device for stabilizing the inter-break arc shape of a gas circuit breaker. Background Art

[0002] Arc interruption is an important topic in the electrical field, which involves multiple complex factors such as high voltage, high temperature, and strong electromagnetic fields. In the process of circuit breaker breaking current, due to the influence of high-speed gas blowing on the fracture, the shape of the arc changes randomly over time, which increases the difficulty of using high-speed sampling and precision measurement technology to capture the dynamic characteristic parameters of the arc. In addition, arc modeling and simulation are key links in circuit breaker design. However, due to the complexity and variability of the arc process, the existing arc model is often difficult to accurately describe the behavior of the arc. It is necessary to further improve and perfect the arc modeling and simulation methods, which requires accurate measurement of the arc-related characteristic parameters during the circuit breaker breaking process. Therefore, measuring and studying the relevant characteristic parameters of the arc in the high-speed gas blowing environment of the circuit breaker has become an important means to understand the arc behavior. Typical circuit breakers use hollow arc contacts and rod-type arc contacts to complete the opening and closing actions. For one side of the hollow arc contact, due to the larger upper annular surface, the arc root position is very unstable during the opening process, which is very unfavorable for the precision measuring instrument to focus on the arc, making it impossible to continuously measure the arc parameters during the breaking process. Therefore, it is necessary to have an arc contact design for the arc extinguishing chamber that will not greatly affect the original airflow field state of the arc extinguishing chamber, and at the same time stabilize the arc root in a relatively small area, so as to realize the continuous measurement of the arc parameters during the circuit breaker breaking process.

[0003] The Chinese invention with the publication number CN115128451A discloses an experimental device for measuring arc parameters between gas circuit breakers. The device adopts a fixed nozzle scheme. The nozzle of the arc extinguishing chamber and the contact on the same side are stationary relative to the housing during the entire opening process, which is helpful for the photographing equipment to collect the arc change shape in the nozzle; the double-sided independent mechanism is used to drive the contact on one side and the piston on the other side to move independently, and the contact movement speed and the gas flow rate and gas flow rate are adjusted by controlling the mechanisms on both sides; an auxiliary contact is added to the rear end of the self-powered arc contact to stabilize the arc root at the static side contact end during the opening process at the auxiliary contact, which is conducive to the shooting of the arc shape. Among them, the auxiliary contact includes a limit rod, a sleeve, a mounting slide, an auxiliary contact contact and a spring. In the opening, the auxiliary contact contact, the mounting slide and the limit rod are pushed to the bottom position of the opening by the thrust of the spring on the limit rod. Even if the upper end surface of the auxiliary contact contact exceeds the upper end surface of the hollow arc contact, the arc root on one side of the hollow arc contact is fixed to the upper end surface area of ​​the auxiliary contact contact. Since the auxiliary contact mentioned in the application document uses a compression spring as the driving force for the movement of the auxiliary contact during the opening process, during driving, due to the heating effect of the arc during the breaking process, the spring is easily affected by high temperature during the experiment, resulting in a decrease in the elastic modulus or even permanent deformation, which makes the spring unable to drive the auxiliary spring or the driving is severely delayed during operation, and cannot meet the corresponding test requirements. Although this phenomenon can be improved by making the spring out of high-temperature-resistant materials, this will further increase the volume of the spring. Due to the volume limitation of the hollow arc contact itself, the space for installing the auxiliary contact at the rear of the hollow arc contact is limited, which increases the difficulty of installing the auxiliary contact inside the arc extinguishing chamber. In addition, due to the need to ensure good conductivity and impact resistance, the auxiliary contact needs to use copper as the processing material, which further increases the moving mass of the auxiliary contact, thereby increasing the requirements for the spring elastic force, further increasing the spring wire diameter, and increasing the design difficulty of the auxiliary contact. At the same time, if the size of the spring and the rear spring fixing cover is increased, the incompressible volume inside the compressed air chamber may increase, thereby reducing the output air pressure of the compressed air chamber, which will not only lead to an increase in the measurement cost, but also affect the reliability of the measurement results. Summary of the invention

[0004] In view of the problems in the prior art of the auxiliary contact structure, in which the spring drive is obstructed due to the heating effect of the electric arc, continuous and stable measurement of arc parameters cannot be achieved, and the auxiliary contact installation is difficult, the present invention provides an arc parameter measuring device between the breaks of a circuit breaker with an auxiliary contact structure.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides an auxiliary contact structure, comprising a boss arranged on the inner wall of a pressure cylinder of a circuit breaker and an auxiliary contact assembly arranged inside the pressure cylinder; The auxiliary contact assembly comprises a piston disc and a motion guide cylinder; the piston disc is connected with a mounting slider and an auxiliary contact contact in sequence; the mounting slider is located inside the motion guide cylinder and slides axially along the motion guide cylinder; the motion guide cylinder is electrically connected to the piston disc; When measuring arc parameters, the motion guide cylinder is installed inside the hollow arc contact of the circuit breaker. When the opening is started, the piston disc is located inside the boss. As the opening is carried out, the piston disc gradually moves toward the fracture direction. During the opening process and when the opening is fully completed, the piston disc separates from the boss, so that a gap is formed between the side of the piston disc away from the fracture and the side of the boss close to the fracture, and the maximum cross-sectional area of ​​the gap is larger than the minimum air guide cross-sectional area upstream of the main nozzle and the auxiliary nozzle in the circuit breaker.

[0006] Furthermore, it also includes a limiting rod, which passes through the piston disc and is connected to the motion guide cylinder, and a position retaining spring is arranged on the limiting rod between the piston disc and the motion guide cylinder.

[0007] Furthermore, a stop shoulder is arranged at the end of the limiting rod away from the motion guide cylinder, and a buffer spring is arranged between the stop shoulder and the piston disc.

[0008] Preferably, the gap between the limiting rod and the piston disc is less than 0.5 mm.

[0009] Preferably, the motion guide cylinder and the piston disk are connected via an electrical flexible connection, and the length of the electrical flexible connection is greater than the maximum distance of relative movement between the end of the motion guide cylinder away from the fracture and the piston disk.

[0010] Preferably, at the beginning of opening the gate, the gap between the piston disc and the protrusion is less than or equal to 5 mm.

[0011] Preferably, the diameter of the auxiliary contact is smaller than the minimum diameter of the inner edge of the hollow arc contact when no external force is applied to the hollow arc contact.

[0012] Preferably, the mounting slide slides inside the moving guide cylinder by direct metal contact or by means of a guide ring.

[0013] Furthermore, the radius of the piston disc and the height of the boss satisfy:

[0014] in, R is the radius of the inner wall of the compression cylinder, H is the boss height, r is the radius of the piston disk, It is the distance between the end face of the boss close to the fracture and the end face of the piston disc away from the fracture when the gate is fully opened. S’ The minimum cross-sectional area of ​​the air guide channel in the upstream area of ​​the main nozzle and auxiliary nozzle.

[0015] The present invention also provides a device for measuring arc parameters between breaks of a circuit breaker, comprising the auxiliary contact structure.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The invention discloses an auxiliary contact structure, comprising a boss arranged on the inner wall of a pressure cylinder of a circuit breaker and an auxiliary contact assembly arranged inside the pressure cylinder; a piston disc is arranged in the auxiliary contact assembly, so that the piston disc cooperates with the boss inside the pressure cylinder, and the pressure difference formed by the movement of the pressure piston in the circuit breaker is used to push the piston disc to move, thereby driving the auxiliary contact contact connected with the piston disc to move and extend out of the upper end surface of the hollow arc contact, stabilizing the arc root on one side of the hollow arc contact on the upper end surface of the auxiliary contact contact, thereby realizing the shooting of the arc shape and the continuous measurement of the arc related parameters; by making the piston disc away from the fracture side and the boss close to the fracture side form a gap during the opening process and when the opening is fully completed The gap is formed by a plurality of holes, and the cross-sectional area of ​​the gap is larger than the minimum air guide cross-sectional area upstream of the main nozzle and the auxiliary nozzle in the circuit breaker, so that the addition of the auxiliary contact structure will not affect the gas delivery of the original compressed air chamber to the nozzle during the breaking process, and the pressure change of the original compressed air chamber during the breaking process and the change of the air flow velocity in the nozzle throat are maintained. The entire driving process avoids relying on the mechanical drive of the spring, thereby effectively avoiding the phenomenon of spring drive lag or non-drive caused by the heating effect of the arc, and can greatly reduce the movement mass and volume of the auxiliary contact structure, thereby reducing the design difficulty and installation difficulty of the auxiliary contact structure, thereby meeting the continuous measurement requirements of arc parameters in the breaking process of the circuit breaker with high efficiency and stability.

[0017] By adopting a limit rod and arranging double springs on both sides of the piston disc, the position-holding spring can be used to ensure that the upper end surface of the auxiliary contact contact always protrudes beyond the upper end surface of the hollow contact when the circuit breaker is in the fully opened position. The buffer spring can also be used to convert the rigid collision between the piston disc and the end of the limit rod in the later stage of the closing operation into an inelastic collision, so as to reduce the impact of the piston disc on the limit rod, thereby effectively increasing the mechanical life of the auxiliary contact structure.

[0018] The gap between the limiting rod and the piston disc is less than 0.5 mm, which can ensure the effective movement of the piston disc without being affected by the limiting rod.

[0019] The motion guide cylinder and the piston disk are connected by an electrical flexible connection, and the length of the electrical flexible connection is greater than the maximum distance of relative movement between the motion guide cylinder away from the fracture end and the piston disk to ensure that the electrical flexible connection does not affect the relative movement between the piston disk and the motion guide cylinder.

[0020] The diameter of the auxiliary contact contact is smaller than the minimum diameter of the inner edge of the arc contact when no external force is applied to the hollow arc contact, so as to ensure that the auxiliary contact contact enters the hollow arc contact and contacts the rod-type arc contact.

[0021] The piston disc radius and the boss height satisfy:

[0022] in, R is the radius of the inner wall of the compression cylinder, H is the boss height, r is the radius of the piston disk, It is the distance between the end face of the boss close to the fracture and the end face of the piston disc away from the fracture when the gate is fully opened. S’ The minimum cross-sectional area of ​​the gas-guiding channel in the upstream area of ​​the main nozzle and the auxiliary nozzle can ensure the need for gas pressure building inside the arc extinguishing chamber during the breaking process.

[0023] A device for measuring arc parameters between circuit breaker breaks includes the above auxiliary contact structure. The device can achieve efficient, stable and continuous measurement of arc parameters between circuit breaker breaks, with more reliable measurement results, longer mechanical life and lower cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure is a schematic diagram of the structure of an auxiliary contact assembly of the present invention.

[0025] Fig. 2 is a motion state structure diagram of the auxiliary contact structure of the present invention when measuring arc parameters between the circuit breaker breaks, wherein a is a relative position state diagram of the piston disc and the boss in the auxiliary contact assembly at the start of opening, b is a relative position state diagram of the piston disc and the boss in the auxiliary contact assembly during the opening process, and c is a relative position state diagram of the piston disc and the boss in the auxiliary contact assembly when the opening is fully completed.

[0026] Figure 3 Design flow chart for piston disc radius and boss height.

[0027] Among them, 1-piston disc, 2-mounting slider, 3-auxiliary contact contact, 4-movement guide cylinder, 5-, 6-position holding spring, 7-buffer spring, 8-electrical flexible connection, 9-auxiliary contact assembly, 10-boss, 11-pressure cylinder, 12-pressure piston, 13-hollow arc contact, 14-auxiliary nozzle, 15-main nozzle, 16-rod type arc contact. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0029] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0031] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0032] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0033] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0035] The present invention provides an auxiliary contact structure, comprising a boss 10 arranged on the inner wall of a pressure cylinder 11 of a circuit breaker and an auxiliary contact assembly 9 arranged inside the pressure cylinder 11; The auxiliary contact assembly 9 includes a piston disc 1 and a motion guide cylinder 4; the piston disc 1 is sequentially connected with a mounting slide 2 and an auxiliary contact 3; the mounting slide 2 is located inside the motion guide cylinder 4 and slides axially along the motion guide cylinder 4; the motion guide cylinder 4 is electrically connected to the piston disc 1; When measuring arc parameters, the motion guide cylinder 4 is installed inside the hollow arc contact 13 of the circuit breaker. When the opening is started, the piston disc 1 is located inside the boss 10. As the opening is carried out, the piston disc 1 gradually moves toward the fracture direction. During the opening process and when the opening is fully completed, the piston disc 1 is separated from the boss 10, so that a gap is formed between the side of the piston disc 1 away from the fracture and the side of the boss 10 close to the fracture, and the maximum cross-sectional area of ​​the gap is larger than the minimum air guide cross-sectional area upstream of the main nozzle 15 and the auxiliary nozzle 14 in the circuit breaker.

[0036] Example 1 See also Figure 1 2 , the present invention discloses an auxiliary contact structure, including a boss 10 disposed on the inner wall of a pressure cylinder 11 of a circuit breaker and an auxiliary contact assembly 9 disposed inside the pressure cylinder 11; See also Figure 1 The auxiliary contact assembly 9 includes a piston disc 1, a motion guide cylinder 4 and a limit rod 5; the piston disc 1 is connected with a mounting slider 2 and an auxiliary contact contact 3 in sequence; the mounting slider 2 is located inside the motion guide cylinder 4 and slides axially along the motion guide cylinder 4; the motion guide cylinder 4 is electrically connected to the piston disc 1; the limit rod 5 passes through the piston disc 1 and is connected to the motion guide cylinder 4, and the piston disc 1 drags the mounting slider 2 and the auxiliary contact contact 3 to move; a position holding spring 6 is arranged between the motion guide cylinder 4 and the piston disc 1; a stop shoulder is arranged at the end of the limit rod 5 away from the motion guide cylinder 4, and a buffer spring 7 is arranged between the stop shoulder and the piston disc 1; Referring to FIG. 2 , when measuring arc parameters, the motion guide cylinder 4 is installed inside the hollow arc contact 13 of the circuit breaker. When the opening is started, the piston disc 1 is located inside the boss 10. As the opening is carried out, the piston disc 1 gradually moves toward the fracture direction. During the opening process, the piston disc 1 is separated from the boss 10, so that a gap is formed between the side of the piston disc 1 away from the fracture and the side of the boss 10 close to the fracture, and the maximum cross-sectional area of ​​the gap is larger than the minimum air guide cross-sectional area upstream of the main nozzle 15 and the auxiliary nozzle 14 in the circuit breaker.

[0037] The structure adopts the piston disc 1 at the tail end of the auxiliary contact assembly to cooperate with the boss 10 inside the compressed air cylinder 11 of the circuit breaker, and utilizes the pressure difference formed by the movement of the compressed air piston 12 to push the auxiliary contact contact 3 to move and extend the upper end surface of the hollow arc contact 13 to contact the rod-type arc contact 16, so that the arc root on one side of the hollow arc contact 13 is stabilized on the upper end surface of the auxiliary contact contact 3, which is helpful for the shooting of the arc shape and the measurement of arc-related parameters; during the opening process and when the opening is fully opened, a gap is formed between the side of the piston disc 1 away from the fracture and the side of the boss 10 close to the fracture, and the maximum cross-sectional area corresponding to the gap at the moment of the opening is greater than the minimum air guide cross-sectional area upstream of the main nozzle 15 and the auxiliary nozzle 14 in the circuit breaker, so as to maintain the pressure change of the original compressed air chamber during the opening process and the change of the air flow velocity of the nozzle throat; the entire driving process relies on the pressure difference formed by the movement of the compressed air piston 12, and the arc heating has almost no effect on the driving, and the structure is simple and easy to install, which can meet the needs of continuous and stable measurement of arc parameters between the circuit breaker fractures.

[0038] Example 2 See also Figure 1 2 , the present invention discloses an auxiliary contact structure, including a boss 10 disposed on the inner wall of a pressure cylinder 11 of a circuit breaker and an auxiliary contact assembly 9 disposed inside the pressure cylinder 11; See also Figure 1The auxiliary contact assembly 9 includes a piston disc 1 and a motion guide cylinder 4; the piston disc 1 is connected with a mounting slider 2 and an auxiliary contact contact 3 in sequence. Preferably, the piston disc 1 and the mounting slider 2 and the mounting slider 2 and the auxiliary contact contact 3 are fixed by threads or screws, and the diameter of the auxiliary contact contact 3 is smaller than the minimum diameter of the inner edge of the hollow arc contact 13 when no external force is applied; the mounting slider 2 is located inside the motion guide cylinder 4, and slides axially along the motion guide cylinder 4 by direct metal contact or a guide ring; the motion guide cylinder 4 and the piston disc 1 are connected by an electrical flexible connection 8, and the length of the electrical flexible connection 8 is greater than the maximum distance of relative movement between the end of the motion guide cylinder 4 away from the fracture and the piston disc 1, and the installation position of the electrical flexible connection 8 cannot affect the free sliding of the auxiliary contact contact 3 in the motion guide cylinder 4, and a plurality of limit rods 5 are fixedly connected to the side of the motion guide cylinder 4 away from the fracture, and the limit rods 5 pass through the piston disc 1, and a stop shoulder is provided at the end of the limit rod 5, and the stop shoulder A buffer spring 7 is arranged between the piston disc 1. During the closing process, when the rod-type arc contact 16 hits the auxiliary contact contact 3 and pushes it to the closed position, the buffer spring 7 acts as a buffer for the piston disc 1 before the closing position is fully reached, thereby reducing the rigid impact of the closing collision on the auxiliary contact structure, so as to achieve the purpose of improving the service life of the structure; a retaining spring 6 is arranged on the limit rod between the piston disc 1 and the motion guide cylinder 4, and the position retaining spring 6 remains in a stretched state when the closing position is fully reached and the opening position is fully reached, that is, a pulling force in the direction of the fracture is always provided to the piston disc 1, so as to maintain the position of the auxiliary contact assembly 9 at the moment of the opening position; in addition, since the position retaining spring 6 always provides a pulling force in the direction of the fracture to the piston disc 1, during the opening process of the circuit breaker, the position retaining spring 6 can also provide a pulling force in the same direction of movement to the piston disc 1, so as to facilitate the movement of the auxiliary contact; preferably, the gap between the piston disc 1 and the limit rod is less than or equal to 0.5 mm, and the piston disc 1 can slide freely on the limit rod 5.

[0039] When measuring arc parameters, the motion guide cylinder 4 is installed inside the hollow arc contact 13 of the circuit breaker by means of threads or screws; See also Figure 2a When the opening movement starts, the piston disc 1 is located inside the boss 10. At this time, when the auxiliary contact contact 3 is fully closed, the end face of the piston disc 1 away from the fracture is flush with the end face of the boss 10 away from the fracture, or the end face of the piston disc 1 away from the fracture is closer to the fracture than the end face of the boss 10 away from the fracture. After the opening movement starts, the compressed air piston 12 in the circuit breaker can quickly work on the gas in the compressed air cylinder 11 on the side of the piston disc 1 away from the fracture, forming a pressure difference on both sides of the piston disc 1, and pushing the auxiliary contact contact 3 to move toward the fracture direction.

[0040] See also Figure 2bAs the opening is carried out, the piston disc 1 gradually moves toward the fracture direction. When the piston disc 1 moves to the end face on the other side of the boss 10, the relative position between the two meets the following conditions: when the upper end face of the auxiliary contact contact 3 moves to be flush with the upper end face of the hollow arc contact 13, the end face of the boss 10 close to the fracture should be within 10 mm of the end face of the piston disc 1 away from the fracture direction, that is, the end face of the piston disc 1 away from the fracture direction is about to move to or has just reached the position of the end face of the boss 10 close to the fracture; preferably, the end face of the boss 10 close to the fracture is flush with the end face of the piston disc 1 away from the fracture direction. When the auxiliary contact contact 3 moves to the bottom opening position, the cross-sectional area of ​​the gap formed between the end face of the boss 10 close to the fracture and the end face of the piston disc 1 away from the fracture direction will reach the maximum value, that is, the ventilation volume that can enter the nozzle area through the above gap will reach the maximum value at this time.

[0041] See also Figure 2c When the gate is fully opened, the piston disc 1 is separated from the boss 10, so that a gap is formed between the side of the piston disc 1 away from the fracture and the side of the boss 10 close to the fracture, and the cross-sectional area of ​​the gap is larger than the minimum air guide cross-sectional area upstream of the main nozzle 15 and the auxiliary nozzle 14 in the circuit breaker. When the piston disk 1 is in the bottom position of the circuit breaker opening, that is, the piston disk 1 can reach the position closest to the fracture during the circuit breaker opening movement, the cross-sectional area of ​​the gap formed between the end face of the boss 10 close to the fracture and the end face of the piston disk 1 away from the fracture should be larger than the minimum gas guide cross-sectional area of ​​the upstream area of ​​the nozzle, so as to ensure that the gas inside the compressed air chamber can smoothly enter the nozzle area during the opening process, and the amount of gas introduced into the nozzle area will not be affected by the cross-sectional area of ​​the gap formed between the boss 10 and the piston disk 1. Therefore, the setting of the radius of the piston disk 1 needs to meet the following conditions: the radial length of the gap between the boss 10 and the piston disk 1 is less than or equal to 5mm, preferably, less than or equal to 1mm. The cross-sectional area of ​​the gap formed between the boss 10 and the piston disk 1 can be estimated according to the following method: Assuming that the radius of the inner wall of the compressed air cylinder 11 is R , the height of boss 10 is H , the radius of piston disk 1 is r The distance between the end face of the boss 10 close to the fracture and the end face of the piston disc 1 away from the fracture is ΔL , the cross-sectional area of ​​the gap formed between the boss 10 and the piston disc 1 S for : During the design process, > S’ ; See also Figure 3 In the process of auxiliary contact structure design, the radius r of the piston disk 1 is first selected and determined, according to the radius of the inner wall of the compressed air chamber. RThe height of the boss 10 is determined by the radial length of the gap between the boss 10 and the piston plate 1 being less than or equal to 5 mm. H The value of the gas-guiding maximum cross-sectional area of ​​the gap formed between the boss 10 and the piston disc 1 is calculated by the above formula S and the minimum cross-sectional area of ​​the air guide channel in the upstream area of ​​the nozzle S’ In comparison, if S Greater than S’ , indicating that the amount of gas conducted through the gap formed between the boss 10 and the piston disk 1 in the compressed air chamber is greater than the maximum amount of gas conducted from the nozzle to the throat and downstream area. The gap formed between the boss 10 and the piston disk 1 will not reduce the volume of gas delivered from the compressed air chamber to the nozzle. Then the radius of the piston disk 1 r and the height of boss 10 H Meet the design requirements; if S Less than S’ , it means that the air volume through the gap formed between the boss 10 and the piston disc 1 in the compressed air cylinder 11 is less than the maximum air volume released from the nozzle to the throat and downstream area. The gap formed between the boss 10 and the piston disc 1 will reduce the volume of gas delivered from the compressed air chamber to the nozzle, so the radius of the piston disc 1 needs to be readjusted. r and the height of boss 10 H , until reaching S Greater than S’ result.

[0042] The present invention also provides a device for measuring arc parameters between circuit breaker breaks, including the auxiliary contact structure described above. The device can achieve efficient, continuous and stable measurement of arc parameters between circuit breaker breaks, with more reliable measurement results, longer mechanical life and lower cost.

[0043] In summary, the present invention provides an auxiliary contact structure and a device for measuring arc parameters between circuit breaker breaks, which are composed of an auxiliary contact assembly 9 installed at the rear end of a hollow arc contact 13 and a boss 10 arranged inside a pressure cylinder 11. In the process of breaking the current of the circuit breaker, the auxiliary contact assembly 9 stabilizes the arc root on one side of the hollow arc contact 13 at the end of the auxiliary contact contact 13 to reduce the active area of ​​the arc root, which is conducive to the shooting of the arc shape and the measurement of related parameters; through the cooperation of the boss 10 and the piston disc 1, a pressure difference is formed on both sides of the piston disc 1 at the beginning of the opening movement, which pushes the auxiliary contact assembly 9 to move, and passes through the just-opened position of the arc contacts on both sides. Subsequently, the high-pressure gas in the pressure cylinder 11 enters the nozzle through the gap between the boss 10 and the piston disc 1, forming a high-speed air blow, reducing the arc temperature, and completing the current breaking. The whole process is driven by the air pressure difference on both sides of the piston disc 1, which reduces the influence of arc heat generation on the drive. At the same time, the structure is simple, easy to install, and has a long service life, which can meet the needs of continuous and stable measurement of arc parameters.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to impose any limitation on the technical solution of the present invention. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can also be subjected to several simple modifications and substitutions, and these modifications and substitutions are also within the scope of protection covered by the claims.

Claims

1. An auxiliary contact structure, characterized in that: It comprises a boss (10) arranged on the inner wall of a pressure cylinder (11) of a circuit breaker and an auxiliary contact assembly (9) arranged inside the pressure cylinder (11); The auxiliary contact assembly (9) comprises a piston disc (1) and a motion guide cylinder (4); the piston disc (1) is sequentially connected to a mounting slide block (2) and an auxiliary contact contact (3); the mounting slide block (2) is located inside the motion guide cylinder (4) and slides axially along the motion guide cylinder (4); the motion guide cylinder (4) is electrically connected to the piston disc (1); When measuring arc parameters, the motion guide cylinder (4) is installed inside the hollow arc contact (13) of the circuit breaker. When the opening is started, the piston disc (1) is located inside the boss (10). As the opening is carried out, the piston disc (1) gradually moves toward the direction of the fracture. During the opening process and when the opening is fully completed, the piston disc (1) is separated from the boss (10), so that a gap is formed between the side of the piston disc (1) away from the fracture and the side of the boss (10) close to the fracture, and the maximum cross-sectional area of ​​the gap is larger than the minimum air guide cross-sectional area upstream of the main nozzle (15) and the auxiliary nozzle (14) in the circuit breaker.

2. The auxiliary contact structure according to claim 1, characterized in that: It also comprises a limiting rod (5), the limiting rod (5) passing through the piston disc (1) and connected to the motion guide cylinder (4), and a position retaining spring (6) is arranged on the limiting rod (5) between the piston disc (1) and the motion guide cylinder (4).

3. The auxiliary contact structure according to claim 2, characterized in that: A stop shoulder is provided at the end of the limiting rod (5) away from the motion guide cylinder (4), and a buffer spring (7) is provided between the stop shoulder and the piston disc (1).

4. The auxiliary contact structure according to claim 2 or 3, characterized in that: The gap between the limiting rod (5) and the piston disc (1) is less than 0.5 mm.

5. The auxiliary contact structure according to claim 1, characterized in that: The motion guide cylinder (4) and the piston disk (1) are connected via an electrical flexible connection (8), and the length of the electrical flexible connection (8) is greater than the maximum distance of relative movement between the end of the motion guide cylinder (4) away from the fracture and the piston disk (1).

6. The auxiliary contact structure according to claim 1, characterized in that: At the beginning of gate opening and during gate opening, the gap between the piston disc (1) and the protrusion (10) is less than or equal to 5 mm.

7. The auxiliary contact structure according to claim 1, characterized in that: The diameter of the auxiliary contact (3) is smaller than the minimum diameter of the inner edge of the hollow arc contact (13) when no external force is applied.

8. The auxiliary contact structure according to claim 1, characterized in that: The mounting slide block (2) slides inside the moving guide cylinder (4) through direct metal contact or through a guide ring.

9. The auxiliary contact structure according to claim 1, characterized in that: The radius of the piston disc (1) and the height of the boss (10) satisfy: in, R is the radius of the inner wall of the pressure cylinder (11), H is the height of the boss (10), r is the radius of the piston disk (1), is the distance between the end face of the boss (10) close to the fracture and the end face of the piston disc (1) away from the fracture when the gate is fully opened, S’ The minimum cross-sectional area of ​​the air guide passage in the upstream area of ​​the main nozzle (15) and the auxiliary nozzle (14).

10. A device for measuring arc parameters between circuit breaker breaks, characterized in that: The auxiliary contact structure comprises the auxiliary contact structure as described in any one of claims 1 to 9.

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