An arc extinguishing device for air-insulated grounding switches

Abstract

This invention relates to the technical field of arc extinguishing and discloses an arc extinguishing device for an air-insulated grounding switch, comprising: a cylinder, a stationary contact seat, and a moving contact seat. The stationary contact seat is fixed inside the cylinder, and a stationary contact is fixed on the stationary contact seat. An arc extinguishing body is provided on the stationary contact, and the arc extinguishing body is a pyrolytic polymer. The moving contact seat is fixed inside the cylinder, and a moving contact is movably connected to the moving contact seat. The arc extinguishing body faces the gap between the moving contact and the stationary contact. The stationary contact and the moving contact are electrically connected to the two electrodes of the air-insulated grounding switch, respectively. When the moving contact moves to the point of disengagement, the generated arc pyrolyzes the arc extinguishing body at high temperature to generate arc extinguishing gas. The arc extinguishing gas diffuses to extinguish the arc. Since no sulfides are introduced, and a large amount of gas is generated by the pyrolysis of solid matter to form an airflow, the emission of sulfides is reduced, and the arc extinguishing performance is guaranteed.

Description

Technical Field

[0001] This invention relates to the technical field of arc extinguishing, and in particular to an arc extinguishing device for an air-insulated grounding switch. Background Technology

[0002] Currently, SF6 (sulfur hexafluoride) is widely used in high-voltage power switches due to its high insulation strength, excellent arc-extinguishing performance, and stable chemical properties. However, sulfur hexafluoride has an extremely strong greenhouse effect. The Global Warming Potential (GWP) is measured by mass. On a 100-year timescale, the greenhouse effect of the same mass of sulfur hexafluoride is approximately tens of thousands of times that of carbon dioxide. Moreover, it can remain in the atmosphere for thousands of years, causing extremely strong damage to the atmospheric environment, and its emissions are increasing every year.

[0003] Therefore, reducing or even eliminating the use of sulfur hexafluoride is an urgent problem to be solved for the green development of the power grid. Using environmentally friendly gases, such as synthetic air or other natural gas, to replace SF6 can achieve the goal of environmental protection. However, due to the decline in arc extinguishing performance, fast grounding switches using environmentally friendly gases as the gas medium will generate a strong electric arc when opening, resulting in a significant decrease in breaking performance and making it difficult to extinguish the arc.

[0004] How to improve the arc-extinguishing performance of switches while maintaining environmental protection has become an urgent technical problem to be solved. Summary of the Invention

[0005] The technical problem to be solved by this invention is: how to improve the arc-extinguishing performance of switches while maintaining environmental protection.

[0006] To solve the above-mentioned technical problems, the present invention provides an arc-extinguishing device for an air-insulated grounding switch. The arc-extinguishing device includes: a cylindrical body; a stationary contact seat fixed inside the cylindrical body, a stationary contact fixed on the stationary contact seat, and an arc-extinguishing body provided on the stationary contact, the arc-extinguishing body being a pyrolytic polymer; and a moving contact seat fixed inside the cylindrical body, a moving contact movably connected to the moving contact seat, the arc-extinguishing body facing the gap between the moving contact and the stationary contact; wherein, the stationary contact and the moving contact are electrically connected to the two electrodes of the air-insulated grounding switch respectively, and when the moving contact moves to the point of disengagement, the generated arc pyrolyzes the arc-extinguishing body at high temperature to generate arc-extinguishing gas, the arc-extinguishing gas diffuses to extinguish the arc.

[0007] In one embodiment, the stationary contact is cylindrical and the moving contact is tubular. When the moving contact is electrically connected to the stationary contact, the moving contact is sleeved on the stationary contact.

[0008] In one embodiment, a metal shield is fitted onto the stationary contact, and the metal shield is arranged at a distance from the stationary contact. The gap between the metal shield and the stationary contact is used for the moving contact to extend into.

[0009] In one embodiment, an arc-extinguishing body is provided on the annular arc edge of the metal shield near the stationary contact, and the arc-extinguishing body has a plating structure.

[0010] In one embodiment, when the moving contact is sleeved on the stationary contact, the outer side of the moving contact is in contact with the metal shield.

[0011] In one embodiment, a perforated metal plate is provided inside the cylinder, and a metal shield and a stationary contact are located in the central hole of the perforated metal plate.

[0012] In one embodiment, the stationary contact seat is provided with a support arm, and the support arm is provided with an arc extinguishing body. The arc extinguishing body is located outside the stationary contact and the moving contact, and the arc extinguishing body has a groove facing the contact gap between the stationary contact and the moving contact.

[0013] In one embodiment, the groove is an arc-shaped groove, a V-shaped groove, or a U-shaped groove.

[0014] In one embodiment, the moving contact base is slidably connected to the moving contact or connected via a linkage mechanism.

[0015] In one embodiment, a one-way sealing valve is provided on the cylinder, which opens from the inside of the cylinder to the outside.

[0016] Compared with the prior art, the arc-extinguishing device for an air-insulated grounding switch according to an embodiment of the present invention has the following advantages: Thermolytic polymers include polyoxymethylene, polyethylene, polypropylene, polystyrene, polyurethane, polyvinyl chloride, and foamed polymers. The pyrolysis temperatures of these materials are concentrated between 180 and 380°C, far below the 3000–20000°C range of an electric arc. Therefore, they can stably undergo pyrolysis under the influence of an electric arc, continuously generating a large amount of arc-quenching gas.

[0017] When the circuit breaker is opened, without the protection of sulfur hexafluoride, a high-temperature electric arc will be generated. Under the action of the high-temperature electric arc, the solid thermally decomposable polymer will first reach the critical decomposition temperature locally. The first batch of chemical bonds will break and the macromolecules will decompose. This process will release a small amount of heat, causing the temperature of the surrounding area to rise rapidly. The higher the temperature, the easier it is for the chemical bonds to break, and the decomposition reaction rate will increase exponentially. A large amount of gas will be generated and diffused outward, forming an airflow containing small molecules, which will extinguish the electric arc. Without the electric arc, there is no heat source sufficient to trigger the reaction, so the reaction stops.

[0018] Because it uses an arc-triggered gas generator, it no longer relies on sulfur hexafluoride and can use environmentally friendly gas. This ensures environmental protection while improving the arc-extinguishing performance of the switch compared to ordinary air-insulated grounding switches. Attached Figure Description

[0019] Figure 1 This is an exemplary photograph of an arc of a conventional air-insulated grounding switch, as shown in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram illustrating the structure of an arc-extinguishing device for an air-insulated grounding switch during shutdown, as exemplarily shown in an embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram illustrating the structure of an arc-extinguishing device for an air-insulated grounding switch during the opening process, as exemplarily shown in an embodiment of the present invention.

[0022] Figure 4 This is a comparison curve of the cooling effect of an arc-extinguishing device for an air-insulated grounding switch, as exemplarily shown in an embodiment of the present invention, with that of the prior art.

[0023] Figure 5 This is a schematic diagram illustrating the structure of the stationary contact and metal shield of an arc-extinguishing device for an air-insulated grounding switch, as exemplarily shown in an embodiment of the present invention.

[0024] Figure 6 This is a simulation diagram illustrating the flow path of the arc-extinguishing gas at the stationary contact of an arc-extinguishing device for an air-insulated grounding switch, as exemplarily shown in an embodiment of the present invention.

[0025] Figure 7 This is an exemplary schematic diagram of another structure of an arc-extinguishing device for an air-insulated grounding switch, as shown in an embodiment of the present invention.

[0026] Figure 8 This is a schematic diagram of the connection structure of an arc-extinguishing device for an air-insulated grounding switch, as exemplarily shown in an embodiment of the present invention.

[0027] Figure label: 1. Cylinder body, 2. Stationary contact seat, 3. Moving contact seat, 21. Stationary contact, 4. Arc extinguishing body, 31. Moving contact, 211. Opening, 5. Metal shielding cover, 6. Perforated metal plate, 7. Support arm, 71. Adjustable rotating structure, 72. First arc frame, 73. Second arc frame, 74. Bolt, 75. Nut, 76. Arc washer. Detailed Implementation

[0028] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0029] It should be understood that although the terms first, second, third, etc., may be used in this invention to describe various structures, these structures should not be limited to these terms. These terms are only used to distinguish structures of the same type from each other. For example, a first structure may also be referred to as a second structure without departing from the scope of this invention, and similarly, a second structure may also be referred to as a first structure. Depending on the context, the word "if" as used herein can be interpreted as "when," "when," or "in response to determination."

[0030] Currently, sulfur hexafluoride, with its outstanding advantages such as high insulation strength, excellent arc extinguishing performance, and stable chemical properties, has long been used as an insulating and arc extinguishing medium in high-voltage power switchgear, with fast grounding switches being a typical example.

[0031] However, sulfur hexafluoride (SF6) is a synthetic gas with an extremely strong greenhouse effect. The greenhouse effect of the same mass of SF6 is tens of thousands of times that of carbon dioxide, and it can remain in the atmosphere for thousands of years, causing severe damage to the atmospheric environment. High-voltage switchgear generates SF6 emissions throughout its entire lifecycle, including operation, gas leaks, routine maintenance, and dismantling. Overall emissions from the industry are showing an increasing trend year by year. Therefore, developing new technological solutions to replace SF6 has become an urgent task in the green and low-carbon development of the power grid.

[0032] To address the environmental issues associated with SF6, the mainstream industry approach is to replace it with environmentally friendly natural gases such as synthetic air and dry air. These gases have no or a low greenhouse effect, thus mitigating greenhouse gas emissions at their source. However, the insulation and arc-quenching properties of media such as synthetic air and dry air are far lower than those of sulfur hexafluoride (SF6). Therefore, their application in fast grounding switches, for example... Figure 1 As shown, when the equipment is in the tripping and disconnecting condition, it will generate an electric arc with greater energy and a longer duration. The arc is difficult to extinguish quickly, which directly causes a significant decrease in the switching performance. At the same time, it aggravates the burning of contacts and internal components, affecting the reliability and service life of the equipment.

[0033] Therefore, under the premise of achieving green operation by using environmentally friendly gaseous media, effectively improving the arc-extinguishing capability of fast grounding switches has become a key technical problem that urgently needs to be solved in this field.

[0034] like Figure 3 or Figure 7 As shown, an arc-extinguishing device for an air-insulated grounding switch according to a preferred embodiment of the present invention includes: a cylinder 1, a stationary contact seat 2, and a moving contact seat 3.

[0035] The stationary contact seat 2 is fixed inside the cylinder 1, and a stationary contact 21 is fixed on the stationary contact seat 2. An arc-extinguishing body 4 is provided on the stationary contact 21. The arc-extinguishing body 4 is a pyrolytic polymer. The moving contact seat 3 is fixed inside the cylinder 1, and a moving contact 31 is movably connected to the moving contact seat 3. The arc-extinguishing body 4 faces the gap between the moving contact 31 and the stationary contact 21. The stationary contact 21 and the moving contact 31 are electrically connected to the two electrodes of the air-insulated grounding switch, respectively. When the moving contact 31 moves to the point of disengagement, the generated arc will pyrolyze the arc-extinguishing body 4 at high temperature to generate arc-extinguishing gas. The arc-extinguishing gas diffuses to extinguish the arc.

[0036] Thermolytic polymers include polyoxymethylene, polyethylene, polypropylene, polystyrene, polyurethane, polyvinyl chloride, and foamed polymers. The pyrolysis temperatures of these materials are concentrated between 180 and 380°C, far below the 3000–20000°C range of an electric arc. Therefore, they can stably undergo pyrolysis under the influence of an electric arc, continuously generating a large amount of arc-quenching gas.

[0037] When the circuit breaker is opened, without the protection of sulfur hexafluoride, a high-temperature electric arc will be generated. Under the action of the high-temperature electric arc, the solid thermally decomposable polymer will first reach the critical decomposition temperature locally. The first batch of chemical bonds will break and the macromolecules will decompose. This process will release a small amount of heat, causing the temperature of the surrounding area to rise rapidly. The higher the temperature, the easier it is for the chemical bonds to break, and the decomposition reaction rate will increase exponentially. A large amount of gas will be generated and diffused outward, forming an airflow containing small molecules, which will extinguish the electric arc. Without the electric arc, there is no heat source sufficient to trigger the reaction, so the reaction stops.

[0038] Because it uses an arc-triggered gas generator, it no longer relies on sulfur hexafluoride and can use environmentally friendly gas. This ensures environmental protection while improving the arc-extinguishing performance of the switch compared to ordinary air-insulated grounding switches.

[0039] refer to Figure 4 The sulfur hexafluoride (SF6) curve represents the radial position versus temperature distribution of a switch using a greenhouse gas. It shows that once the radial position (i.e., the separation distance) exceeds 20 mm, the high-temperature region above 3000 degrees Celsius decreases significantly, corresponding to arc extinguishing. In contrast, with the original switch using air, the high-temperature region above 3000 degrees Celsius persists until approximately 40 mm, indicating poor arc extinguishing.

[0040] The optimized solution of this invention demonstrates excellent arc extinguishing performance at a thickness of less than 20 mm, indicating that the arc extinguishing response speed of the solution in this application is fast enough, and the cooling effect is even better than that of the sulfur hexafluoride solution.

[0041] It is understandable that when the arc-extinguishing body 4 is close to the moving contact 31 and the stationary contact 21, there will always be airflow that can blow into the gap between the stationary contact 21 and the moving contact 31. Therefore, the present invention does not strictly limit the position of the arc-extinguishing body 4, and the corresponding drawings of the present invention also show a variety of fixing forms.

[0042] In one embodiment of the present invention, the stationary contact 21 is columnar and the moving contact 31 is tubular. When the moving contact 31 is electrically connected to the stationary contact 21, the moving contact 31 is sleeved on the stationary contact 21.

[0043] With this structure, when the moving contact 31 and the stationary contact 21 separate, the generated electric arc causes the arc-extinguishing body 4 to pyrolyze. The generated gas forms an airflow that flows over the outer surface of the stationary contact 21 and the inner and outer surfaces of the moving contact 31. Due to the larger contact area, it can achieve a stronger cooling and arc-extinguishing capability.

[0044] Furthermore, in a further embodiment, an opening 211 may also be provided in the middle of the stationary contact 21, such as... Figure 6 In the simulation path shown, some airflow can also flow through the formed opening 211 to enhance the cooling ability of the arc-extinguishing gas on the stationary contact 21 and assist in arc extinguishing.

[0045] In a further embodiment, such as Figure 2 and Figure 3 A metal shield 5 is fitted onto the stationary contact 21 shown. The metal shield 5 is arranged at intervals with the stationary contact 21, and the gap between the metal shield 5 and the stationary contact 21 is used for the moving contact 31 to extend into.

[0046] The added metal shield 5 can achieve electric field homogenization, arc control and insulation protection. Through the Faraday cage effect of the metal shell, it can achieve multi-dimensional protection and ensure the safety and reliability of operation under high voltage conditions.

[0047] Under high voltage conditions, the stationary contact 21, as a metal component, is prone to sharp edge effects, which can lead to electric field distortion and excessively high local field strength. The shield completely surrounds the contact fingers and other components to form a smooth equipotential surface, making the electric field distribution more uniform and reducing the local field strength to a safe threshold. At the same time, it can effectively share the arc energy, reduce the energy impact on the stationary contact 21, and prevent the stationary contact 21 from being burned and damaged or even fused with the moving contact 31.

[0048] In addition, the metal shield 5 is arranged at intervals with the stationary contact 21. The gap formed not only extends into the moving contact 31, but also allows arc-extinguishing gas to enter when the moving contact 31 is separated, thereby enhancing gas flow and heat dissipation.

[0049] The metal shield 5 can be further made into an arc shape, which can weaken the tip effect, uniformize the electric field, guide the electric arc, and make the force more uniform. It is more suitable for high-voltage arc extinguishing conditions than right-angle, flat, and angular structures.

[0050] Furthermore, in a further embodiment, such as Figure 5 As shown, an arc-extinguishing body 4 is provided on the annular arc edge of the metal shield 5 near the stationary contact 21. The arc-extinguishing body 4 has a plating structure.

[0051] Making the arc-extinguishing body 4 into a coated structure can reduce the space occupied, and at the same time, there is no need to introduce a new structure, so there is no need to worry about the arc-extinguishing body 4 and its fixing structure causing new problems.

[0052] The coating structure, combined with the annular arc edge of the metal shield 5, forms a 360-degree surround, giving each direction of the arc a chance to trigger the arc extinguishing body 4, further stimulating the gas generation and arc extinguishing process. This annular design disperses the concentrated volume into various areas. Although the thickness is not large, the overall usable area is greatly increased, effectively reducing arc extinguishing dead zones and improving the arc extinguishing effect.

[0053] It is understood that the arc-extinguishing body 4 in the figure is only an example, and the actual thickness and size are determined according to actual needs.

[0054] Furthermore, in one embodiment of the present invention, such as Figure 2 As shown, when the moving contact 31 is sleeved on the stationary contact 21, the outer side of the moving contact 31 is in contact with the metal shield 5.

[0055] The metal shield 5 and the stationary contact 21 are reliably electrically connected, forming the same potential body. Therefore, when an electric arc is generated, the arc can be guided to trigger the arc extinguishing body 4 located on the metal shield 5, thereby improving the arc extinguishing effect.

[0056] The metal shield 5 and the stationary contact 21 are at the same potential. The arc-shaped shield can form a complete equipotential covering surface, uniformly dispersing the electric field at the edge of the contact and preventing tip discharge. If the two are disconnected and a floating potential is formed, a potential difference will be generated, inducing partial discharge.

[0057] After the fast grounding switch is closed, the entire system is reliably grounded. The metal shield 5 is at the grounding potential along with the stationary contact 21, avoiding the safety hazards caused by the energized floating metal parts and meeting the equipment grounding protection requirements.

[0058] In one embodiment, such as Figure 2 and Figure 3 As shown, the cylinder 1 is provided with a perforated metal plate 6, a metal shield 5 and a stationary contact 21 located in the center hole of the perforated metal plate 6.

[0059] The perforated metal plate 6 can act as an equalizing ring. The metal shield 5 has a smooth curved surface, but due to the limitations of the processing technology, there are inevitable abrupt changes in curvature at the outer edge of the shield. Under high voltage, this is still the strongest point in the field, and corona discharge and partial discharge are likely to occur.

[0060] The perforated metal plate 6, which acts as a ring-shaped equalizing ring, is equivalent to adding a smooth transition edge to the outer ring of the shield, transferring the highest field strength, which was originally concentrated at the edge of the shield, to the surface of the large-diameter ring.

[0061] Thanks to the ring structure, the electric field is uniform in all directions around the circumference, which can weaken the edge effect, control the field strength within a safe range, and avoid insulation breakdown.

[0062] Furthermore, the edges of the perforated metal plate 6 are rounded or curved, leaving no sharp right angles, which can prevent new electric field concentration points.

[0063] The opening and closing of the switch will generate fine metal debris and dust. Suspended metal particles are a common cause of internal discharge and short circuits in GIS. The perforated metal plate 6 forms a physical barrier that can prevent debris from drifting outward to the outer cylinder 1, which can significantly reduce the entry of particles into the critical insulation area and reduce the risk of insulation failure.

[0064] In one embodiment, another structural arrangement is also provided, such as Figure 7 As shown, the stationary contact base 2 is provided with a support arm 7, and the support arm 7 is provided with an arc extinguishing body 4. The arc extinguishing body 4 is located outside the stationary contact 21 and the moving contact 31. The arc extinguishing body 4 has a groove, which faces the contact gap between the stationary contact 21 and the moving contact 31.

[0065] This scheme of adding an arc-extinguishing body 4 to the support arm 7 is simple to arrange, reliable in structure, and has the advantage of low cost. Moreover, since the position of the arc-extinguishing body 4 forms a new tip, it can trigger the arc to touch, effectively causing the arc-extinguishing body 4 to pyrolyze, thereby realizing a large amount of gas production to extinguish the arc.

[0066] It is understood that the connection between the support arm 7 and the stationary contact seat 2 can be any available structure, and the present invention also provides a fixing structure, such as... Figure 8 As shown, the support arm 7 is connected to the first arc frame 72 through an adjustable rotating structure 71. The first arc frame 72 and the second arc frame 73 are connected by several bolts 74 and nuts 75. The inner surfaces of the first arc frame 72 and the second arc frame 73 are provided with arc-shaped washers 76, which are used to increase friction to improve the fastening effect.

[0067] The adjustable rotating structure 71 allows for adjustment of the relative angle between the support arm 7 and the first arc frame 72, thus adapting to static contact seats 2 with different structures.

[0068] In this invention, the groove can be any one of an arc-shaped groove, a V-shaped groove, or a U-shaped groove. Different shapes result in different gas production efficiency and consumption rates, and can be adjusted according to actual project requirements.

[0069] Furthermore, in one embodiment of the present invention, the movable contact base 3 is slidably connected to the movable contact 31 or connected via a linkage mechanism.

[0070] Regardless of the form used, when the moving contact 31 can achieve relative movement with the moving contact base 3, it can achieve connection and disconnection with the stationary contact 21, that is, achieve closing and opening.

[0071] In addition, after repeated pyrolysis, pressure will accumulate inside the cylinder 1. In order to avoid damage to the equipment, in one embodiment of the present invention, a one-way sealing valve is provided on the cylinder 1, which opens from the inside of the cylinder 1 to the outside.

[0072] The one-way sealing valve can automatically release gas when there is too much gas inside, resulting in high pressure, in order to achieve pressure balance and reduce the possibility of excessive pressure causing the cylinder 1 to rupture.

[0073] In summary, sulfur hexafluoride (SF6) is widely used as the arc-extinguishing medium in high-voltage switchgear due to its excellent insulation properties and strong arc-extinguishing capability. However, its significant greenhouse effect and environmental damage pose a challenge to the industry in terms of environmentally friendly alternatives. To address this issue, this invention proposes an improved arc-extinguishing device that effectively enhances arc-extinguishing performance through structural optimization (such as the asymmetrical arrangement of stationary and moving contacts, the annular design of the metal shield, and the coating structure). This device generates arc-triggered gas, avoiding reliance on SF6 and achieving environmentally friendly operation while significantly enhancing arc-extinguishing capability. Experimental data shows that at an arc-extinguishing distance of less than 20 mm, its cooling efficiency and arc-extinguishing speed are superior to traditional SF6 solutions. Furthermore, the multi-dimensional protection mechanism of the metal shield effectively reduces arc energy impact and partial discharge, ensuring the reliability of equipment operation.

[0074] This invention achieves the following technological breakthroughs through structural innovation and material optimization: By employing an asymmetrical arrangement of stationary and moving contacts, combined with a ring-shaped design of a metal shield, efficient diffusion of arc-triggered gas and airflow guidance are achieved.

[0075] The ring structure of the metal shield effectively disperses electric field distortion and reduces the tip effect. At the same time, the combination of plating and arc-shaped gaskets achieves multi-dimensional protection and reduces the risk of insulation breakdown.

[0076] By controlling the uniform electric field of the metal shield, partial discharge of the stationary contacts is reduced, erosion caused by arc energy impact is avoided, and the equipment life is extended.

[0077] The technology has demonstrated its dual advantages of environmental friendliness and arc extinguishing capability in simulation experiments, providing an innovative solution for the green and low-carbon development of high-voltage switchgear.

[0078] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. An arc extinguishing device for an air-insulated grounding switch, characterized in that, The arc-extinguishing device includes: Cylinder (1); A stationary contact seat (2) is fixed inside the cylinder (1). A stationary contact head (21) is fixed on the stationary contact seat (2). An arc-extinguishing body (4) is provided on the stationary contact head (21). The arc-extinguishing body (4) is a pyrolytic polymer. The movable contact seat (3) is fixed inside the cylinder (1), and a movable contact (31) is movably connected to the movable contact seat (3). The arc extinguishing body (4) faces the gap between the movable contact (31) and the stationary contact (21). The stationary contact (21) and the moving contact (31) are electrically connected to the two electrodes of the air-insulated grounding switch, respectively. When the moving contact (31) moves to the point of separation from the moving contact (31), the generated arc will pyrolyze the arc extinguishing body (4) at high temperature to generate arc extinguishing gas. The arc extinguishing gas diffuses to extinguish the arc.

2. The device of claim 1, wherein, The stationary contact (21) is columnar, and the moving contact (31) is tubular. When the moving contact (31) is electrically connected to the stationary contact (21), the moving contact (31) is sleeved on the stationary contact (21).

3. The device of claim 2, wherein, A metal shield (5) is fitted on the stationary contact (21). The metal shield (5) is arranged at a distance from the stationary contact (21). The gap between the metal shield (5) and the stationary contact (21) is used for the moving contact (31) to extend into.

4. The device of claim 3, wherein, The arc extinguishing body (4) is provided on the annular arc edge of the metal shield (5) near the stationary contact (21), and the arc extinguishing body (4) is a plating structure.

5. The device of claim 3, wherein, When the moving contact (31) is sleeved on the stationary contact (21), the outer side of the moving contact (31) contacts the metal shield (5).

6. The device of claim 3, wherein, The cylinder (1) is provided with a perforated metal plate (6), and the metal shield (5) and the stationary contact (21) are located in the center hole of the perforated metal plate (6).

7. The device of claim 1, wherein, The stationary contact seat (2) is provided with a support arm (7), and the support arm (7) is provided with the arc extinguishing body (4). The arc extinguishing body (4) is located outside the stationary contact (21) and the moving contact (31). The arc extinguishing body (4) has a groove, which faces the contact gap between the stationary contact (21) and the moving contact (31).

8. The device of claim 7, wherein, The groove is an arc-shaped groove, a V-shaped groove, or a U-shaped groove.

9. The device of claim 1, wherein, The movable contact seat (3) is slidably connected to the movable contact (31) or connected through a linkage mechanism.

10. The arc-extinguishing device according to claim 1, characterized in that, The cylinder (1) is provided with a one-way sealing valve, which opens from the inside of the cylinder (1) to the outside.

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