Three-phase common-tank fast grounding switch based on clean air insulation and use method

Abstract

The application relates to a three-phase common-box type fast grounding switch based on clean air insulation and a use method, which comprises a grounding shell, a moving contact, a static contact and a moving contact seat, the inner hole of the moving contact seat is sealingly slidably connected with a piston, the piston is fixedly connected with a pull rod, a through hole sealingly slidably connected with the pull rod is arranged at the end of the moving contact seat far from the moving contact; the pull rod is in transmission connection with the output shaft of a spring mechanism through a transmission system; a pressure cavity is formed among the pull rod, the side wall of the moving contact seat and the piston, a blind hole penetrating into the inner hole of the moving contact is arranged in the pull rod, the blind hole and the inner hole of the moving contact form a jet cavity, and the side wall of the blind hole is provided with a jet hole communicating the pressure cavity and the jet cavity. The pull rod drives the moving contact and the piston to synchronously move, the volume of the pressure cavity is compressed when the moving contact is opened, the pressure in the pressure cavity is increased, the jet speed of the clean air is increased, the arc extinguishing effect is improved, and reliable arc extinguishing by taking the clean air as the insulation medium is realized.

Description

Technical Field

[0001] This invention relates to the field of fast grounding switch technology for gas-insulated switchgear, and particularly to a fast grounding switch using clean air as the insulating medium, specifically a three-phase common-enclosure type fast grounding switch based on clean air insulation and its usage method. Background Technology

[0002] Typically, GIS (Gas-insulated Metal-Enclosed Switchgear) is a complete set of switchgear that encloses primary electrical components such as circuit breakers, disconnectors, grounding switches, current transformers, voltage transformers, surge arresters, busbars, incoming and outgoing bushings or cable terminals in a grounded metal housing, filled with insulating gas at a certain pressure as the insulating medium.

[0003] In power grid systems, fast grounding switches primarily function to close short-circuit currents and open induced currents, enabling rapid grounding of busbars or cables. They serve as safety devices for protection and maintenance, playing a crucial role in power grid systems.

[0004] Most existing GIS equipment uses SF6 gas as the insulating medium. However, SF6 is a strong greenhouse gas restricted by international conventions, with a global warming potential (GWP) 23,900 times that of CO2. The research and application of environmentally friendly gas-based power equipment is a crucial technological direction for achieving the "dual carbon" goals of the power system. Among these, electrical equipment using clean air as the insulating medium has the most significant environmental benefits. However, clean air has inferior insulation and arc-extinguishing capabilities compared to SF6 gas, and the arc-extinguishing components of existing fast grounding switches cannot meet the arc-extinguishing requirements when using clean air as the insulating medium. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a three-phase common-enclosure type fast grounding switch and its usage method based on clean air insulation, which meets the arc extinguishing requirements of using clean air as the insulating medium.

[0006] This invention is achieved through the following technical solution: a three-phase common-enclosure type fast grounding switch based on clean air insulation is provided, including a grounding shell, a moving contact and a stationary arc contact disposed within the grounding shell, and a moving contact seat fixed within the grounding shell by an insulating connecting plate. A piston, fixedly connected to the moving contact, is slidably connected to the inner wall of the moving contact seat. A pull rod extending from the moving contact seat away from the moving contact is fixedly connected to the piston. A through hole is opened at the end of the moving contact seat away from the moving contact, which is slidably connected to the pull rod. The pull rod is driven by the output shaft of a spring mechanism through a transmission system. A compressed air chamber is formed between the pull rod, the side wall of the moving contact seat, and the piston. A blind hole penetrating to the inner hole of the moving contact is provided in the pull rod. The side wall of the blind hole is in sealed contact with the side wall of the moving contact. The blind hole and the inner hole of the moving contact form an air jet chamber. An air jet hole communicating between the compressed air chamber and the air jet chamber is opened on the side wall of the blind hole, and the air jet hole is located on the side of the piston facing the compressed air chamber. In this scheme, during the opening process of the grounding switch, the moving contact and the piston move synchronously. The piston compresses the volume of the compressed air chamber, increasing the pressure in the compressed air chamber. This allows clean air in the compressed air chamber to enter the air jet chamber through the air jet hole and be ejected from the moving contact toward one end of the stationary arc contact, extinguishing the arc generated when the moving contact separates from the stationary arc contact and improving the arc extinguishing effect.

[0007] As an optimization, the piston has an axially penetrating inner hole. The inner hole wall of the piston has a first support platform and a second support platform arranged sequentially along the axial direction. A retaining plate supported on the first support platform is fixed to the outer wall of the moving contact. A flange plate, which is in sealing contact with the moving contact, is fixed to the end of the pull rod facing the moving contact. The flange plate is supported on the second support platform and is bolted to the second support platform. This optimized solution not only integrates the pull rod, moving contact, and piston into a single unit, but also uses the flange plate to press and fix the moving contact while the pull rod is fixed to the piston, eliminating the need for additional fixing bolts for the moving contact, ensuring the integrity of the moving contact, and improving the sealing performance between the pull rod and the moving contact.

[0008] As an optimization, a watchband contact finger is fixedly provided on the outer circular surface of the piston, and the watchband contact finger is slidably connected to the inner wall of the moving contact seat. This optimization scheme ensures flow between the piston and the moving contact seat by setting the watchband contact finger.

[0009] As an optimization, a nozzle is installed in the inner hole of the moving contact, and a number of protrusions arranged at intervals along the circumference are fixed on the inner wall of the nozzle. This optimization scheme further accelerates the ejected clean air by setting the nozzle, thereby achieving a better arc extinguishing effect.

[0010] As an optimization, the transmission system includes a transmission shaft rotatably connected to the grounded housing, an inner crank arm fixedly mounted on the transmission shaft, and a linkage mechanism connecting the transmission shaft and the output shaft of the spring mechanism. Two opposing fork plates are fixedly mounted at the end of the inner crank arm away from the transmission shaft. Each fork plate is rotatably connected to a slider via a pin, and the two sliders are located on opposite sides of the fork plates. An insulating joint is fixedly connected at the end of the pull rod away from the moving contact, and a metal joint is fixedly connected at the end of the insulating joint away from the pull rod. The metal joint is located between the two fork plates, and a groove adapted to the slider is provided on the side of the metal joint. The length direction of the groove is consistent with the radial direction of the metal joint and perpendicular to the axial direction of the pin. In use, the output shaft of the spring mechanism drives the transmission shaft to rotate via the linkage mechanism, thereby driving the inner crank arm to rotate. When the inner crank arm rotates, force is transmitted through the slider, causing the pull rod to move axially. The provided groove allows the slider to slide within the groove, displacing it relative to the metal joint and avoiding interference with the rotation of the inner crank arm.

[0011] As an optimization, the linkage mechanism includes an outer crank arm of the main body fixedly connected to the drive shaft, and an outer crank arm of the mechanism fixedly connected to the output shaft of the spring mechanism. A transmission link is hinged to the end of the outer crank arm away from the output shaft of the spring mechanism. The end of the transmission link away from the outer crank arm is hinged to the end of the outer crank arm of the main body away from the drive shaft. The plane containing the outer crank arm, transmission link, and outer crank arm is perpendicular to the axes of the drive shaft and the output shaft of the spring mechanism. This optimized linkage mechanism has a simple structure, reliable transmission, and reduces manufacturing costs and complexity.

[0012] As an optimization, a guide rod is also fixed inside the grounding housing. The guide rod passes downward through a metal joint, and the metal joint is slidably connected to the guide rod. This optimization scheme, by setting the guide rod, provides guidance for the movement of the pull rod during opening and closing, ensuring the accuracy of the closing action.

[0013] As an optimization, a partition is fixedly installed in the inner hole of the pull rod. A blind hole is formed on the side of the partition facing the moving contact, and a hollow cavity is formed on the other side of the partition. The insulating joint extends into the hollow cavity and is threadedly connected to the inner wall of the hollow cavity. The end of the insulating joint away from the pull rod extends into the metal joint and is threadedly connected to the metal joint. The insulating joint has a through hole with a diameter larger than the outer diameter of the pull rod. This optimized solution, by setting a partition to form a hollow cavity, not only reduces the weight of the pull rod but also facilitates a detachable threaded connection with the insulating joint. It also provides space for the guide rod to enter, allowing it to extend into the inner hole of the insulating joint and the hollow cavity, which helps to increase the guiding distance of the guide rod.

[0014] As an optimization, three movable contact seats are fixedly mounted on the insulating connecting plate. The three movable contact seats are arranged in a straight line, and the pull rods corresponding to the three movable contact seats are connected to the output shaft of the spring mechanism through the same transmission system. This optimized scheme realizes three-phase common box and ensures the synchronicity of the movement of the movable contacts corresponding to the three movable contact seats.

[0015] This solution also provides a method for using a three-phase common-enclosure fast grounding switch based on clean air insulation, including the following aspects: a. When the circuit is opened, the output shaft of the spring mechanism drives the pull rod away from the stationary arc contact through the transmission system, thereby driving the moving contact to move towards the open position. During the process of the moving contact moving towards the open position, the piston compresses the volume of the air chamber, so that the clean air in the air chamber enters the air chamber through the air jet hole and is sprayed towards the stationary arc contact, extinguishing the electric arc between the moving contact and the stationary arc contact. b. When closing the circuit, the output shaft of the spring mechanism drives the pull rod to move toward the stationary arc contact through the transmission system, thereby driving the moving contact to move toward the closing position. During the process of the moving contact moving toward the closing position, the piston moves toward the side where the stationary arc contact is located, and the volume of the compressed air chamber increases. Under the action of pressure difference, the clean gas in the grounding shell enters the jet chamber and enters the compressed air chamber through the jet hole.

[0016] The beneficial effects of this invention are as follows: by using a pull rod to drive the moving contact and the piston to move synchronously, while the moving contact opens, the piston compresses the volume of the compressed air chamber, increases the pressure inside the compressed air chamber, improves the clean air ejection speed, and improves the arc extinguishing effect, thereby realizing reliable arc extinguishing using clean air as an insulating medium. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the tripped state of the fast grounding switch of the present invention; Figure 2 This is a schematic diagram of the closing state of the fast grounding switch of the present invention; Figure 3 This is a schematic diagram of the transmission system structure of the present invention; Figure 4 This is a schematic diagram of the moving contact unit structure; Figure 5 This is a schematic diagram of the stationary contact unit structure; Figure 6 This is a schematic diagram showing the connection between the slider and the metal connector; As shown in the figure: 1. Grounding housing; 2. Spring mechanism; 3. Transmission system; 4. Moving contact unit; 5. Stationary contact unit; 6. Grounding handle; 7. Grounding copper busbar; 8. Air jet hole; 31. Outer crank arm of mechanism; 32. Transmission connecting rod; 33. Outer crank arm of body; 34. Transmission shaft; 35. Inner crank arm of body; 36. Slider; 37. Guide rod; 38. Insulating connecting plate; 40. Guide ring; 41. Metal joint; 42. Insulating joint; 43. Sealing ring; 44. Pull rod; 45. Moving contact seat; 46. Piston; 47. Watch strap contact finger; 48. Moving contact; 49. Nozzle; 51. Stationary arc contact; 52. Shielding cover; 53. Contact piece; 54. Spring contact finger; 55. Stationary contact seat. Detailed Implementation

[0018] To clearly illustrate the technical features of this solution, the following detailed implementation method will be used to describe the solution.

[0019] like Figure 1 and 2 The diagram illustrates a three-phase common-enclosure type fast grounding switch based on clean air insulation, comprising a grounding housing 1, and a moving contact 48 and a stationary arc contact 51 disposed within the grounding housing 1. The grounding housing is filled with clean air. The grounding housing 1 is fixed to the three-position unit's outlet, serving as structural support and providing gas sealing. Both the moving contact and the stationary arc contact are existing technologies. The moving contact adopts a copper tube structure and belongs to the moving contact unit 4. The moving contact has an axially penetrating inner hole. The stationary arc contact belongs to the stationary contact unit 5, as shown in the diagram. Figure 5 As shown, the stationary contact unit 5 also includes a shield 52, a contact piece 53, a spring contact finger 54, and a stationary contact base 55. The stationary contact base 55 is connected to the main circuit by bolts. The stationary arc contact 51 is fastened to the stationary contact base 55 by threads and screws. The contact piece 53 is fastened to the stationary contact base 55 by the spring contact finger 54. The shield 52 is installed on the outside to improve the electric field.

[0020] This embodiment of the three-phase common-enclosure fast grounding switch based on clean air insulation also includes a moving contact seat 45 fixed inside the grounding housing via an insulating connecting plate 38. The moving contact seat 45 is assembled and connected to a grounding handle 6 fixed on the grounding housing via a grounding copper busbar 7. A piston 46, which is fixed to the moving contact, is slidably sealed to the inner wall of the moving contact seat. A pull rod 44, extending from the moving contact seat away from the moving contact, is fixed to the piston 46. A through hole, which is slidably sealed to the pull rod, is opened at the end of the moving contact seat away from the moving contact. A sealing ring 43 is provided between the through hole wall and the pull rod to improve the sealing effect of the compressed air chamber. In this embodiment, the pull rod is an iron pull rod. In this embodiment, the moving contact is located above the stationary arc contact. The moving contact seat is a shell structure with an open lower end. The through hole is opened at the center of the top plate of the moving contact seat. The pull rod, piston, and moving contact seat are coaxially arranged.

[0021] The pull rod is connected to the output shaft of the spring mechanism 2 via the transmission system 3. The spring mechanism 2 also adopts existing technology, providing power to the movement of the pull rod to realize the opening and closing actions. In this embodiment, three moving contact seats are fixed on the insulating connection plate to form a three-phase common box structure. The three moving contact seats are arranged in a straight line, and the pull rods corresponding to the three moving contact seats are connected to the output shaft of the spring mechanism via the same transmission system.

[0022] A compressed air chamber is formed between the pull rod 44, the side wall of the moving contact seat, and the piston. A blind hole is provided in the pull rod, which extends to the inner hole of the moving contact. The side wall of the blind hole is in sealed contact with the side wall of the moving contact. The blind hole and the inner hole of the moving contact form a jet chamber. A plurality of jet holes 8 are provided on the side wall of the blind hole, which connect the compressed air chamber and the jet chamber. The jet holes are located on the side of the piston facing the compressed air chamber. In this embodiment, the jet holes are located above the piston, and the jet holes are set in two layers, with the jet holes in each layer evenly distributed circumferentially. The piston has an axially penetrating inner hole. The inner hole wall of the piston has a first support platform and a second support platform arranged sequentially along the axial direction. The upper end of the outer wall of the moving contact is fixed with a retaining plate supported on the first support platform, and the upper end face of the moving contact is flush with the second support platform. The end of the pull rod facing the moving contact is fixed with a flange plate that is in sealing contact with the moving contact. The upper end of the moving contact abuts against the lower end face of the flange plate to better achieve a seal. The flange plate is supported on the second support platform and is fixed to the second support platform by bolts. The moving contact is pressed and fixed to the piston by the flange plate of the pull rod, and an abutment seal is formed between the moving contact and the flange plate.

[0023] The outer surface of the piston is fixed with a watch strap finger 47, which is slidably connected to the inner wall of the moving contact seat to ensure the flow between the piston 46 and the moving contact seat 45.

[0024] A guide ring 40 is also fitted and fixed on the outer surface of the piston. When the moving contact, piston and pull rod move together to open and close, the guide ring 40 plays a guiding and sealing role, which is conducive to further establishing the air pressure in the air chamber.

[0025] The inner hole of the moving contact 48 is equipped with a nozzle 49. The inner wall of the nozzle 49 is fixed with a number of protrusions arranged at intervals along the circumference. The protrusions reduce the cross-sectional area through which the air flows, thereby improving the air flow speed and further improving the arc extinguishing effect.

[0026] The transmission system 3 includes a transmission shaft 34 rotatably connected to the grounded housing 1, an inner crank arm 35 fixedly mounted on the transmission shaft 34, and a linkage mechanism connecting the transmission shaft and the output shaft of the spring mechanism. Two opposing fork plates are fixedly mounted at the end of the inner crank arm 35 away from the transmission shaft. Each fork plate is rotatably connected to a slider 36 via a pin, and the two sliders are located on opposite sides of the fork plates. The pin is rotatably connected to the fork plates and can be rotatably or fixedly connected to the sliders. An insulating connector 42 is fixedly connected at the end of the pull rod 44 away from the moving contact. A metal connector 41 is fixedly connected at the end of the insulating connector away from the pull rod. The metal connector is located between the two fork plates, and a groove adapted to the slider is opened on the side of the metal connector. The length direction of the groove is consistent with the radial direction of the metal connector and perpendicular to the axial direction of the pin. The length of the slide is perpendicular to the direction of the pull rod's movement. When the crank arm inside the body rotates, the force is transmitted through the slider, causing the pull rod to move along its axial direction. Through the slide, the slider can be displaced laterally relative to the metal joint, thus avoiding interference with the rotation of the crank arm inside the body.

[0027] The linkage mechanism of this embodiment includes an outer crank arm 33 fixedly connected to the transmission shaft, and an outer crank arm 31 fixedly connected to the output shaft of the spring mechanism. A transmission link 32 is hinged to the end of the outer crank arm 31 away from the output shaft of the spring mechanism. The end of the transmission link 32 away from the outer crank arm 31 is hinged to the end of the outer crank arm 33 away from the transmission shaft. The plane containing the outer crank arm 33, the transmission link 32 and the outer crank arm 31 is perpendicular to the axis of the transmission shaft and the output shaft of the spring mechanism.

[0028] In this embodiment, a guide rod 37 is also fixed inside the grounding housing. The upper end of the guide rod 37 is connected to the grounding housing by a thread. The guide rod 37 passes downward through a metal connector. The metal connector is slidably connected to the guide rod. A guide hole adapted to the guide rod is provided on the metal connector.

[0029] A partition is fixedly installed in the inner hole of the pull rod. A blind hole is formed on the side of the partition facing the moving contact, and a hollow cavity is formed on the other side of the partition. In this embodiment, the blind hole is located below the partition, and the hollow cavity is located above the partition. An insulating joint extends downward into the hollow cavity and is threadedly connected to the inner wall of the hollow cavity. The end of the insulating joint away from the pull rod extends into the metal joint and is threadedly connected to the metal joint. In this embodiment, the upper end of the insulating joint is threadedly connected to the metal joint. The insulating joint has a through hole with a diameter larger than the outer diameter of the pull rod. The inner hole of the insulating joint communicates with the hollow cavity, and the diameter of the hollow cavity is also larger than the outer diameter of the pull rod, so as to accommodate the guide rod and increase the guiding movement distance.

[0030] This embodiment describes the usage of a three-phase common-enclosure fast grounding switch with clean air insulation: a. When the circuit is open, the output shaft of the spring mechanism drives the pull rod away from the stationary arc contact through the transmission system, thereby driving the moving contact to the open position. During the movement of the moving contact to the open position, the piston compresses the volume of the air chamber, so that the clean air in the air chamber enters the air chamber through the air jet hole and is ejected toward the stationary arc contact. The gas is further accelerated by the blocking effect of the nozzle, forming a high-speed air blow, which quickly extinguishes the arc between the moving contact and the stationary arc contact.

[0031] The transmission system drives the pull rod away from the static arc contact to move it away from the static arc contact. This means that the linkage mechanism transmits the power released by the output shaft of the spring mechanism to the transmission shaft, causing the transmission shaft to rotate clockwise. The transmission shaft then drives the crank arm inside the main body to rotate clockwise. By using the force transmitted by the slider, the pull rod is pulled upward to achieve the opening of the circuit breaker.

[0032] b. When closing the circuit, the output shaft of the spring mechanism drives the pull rod to move toward the stationary arc contact through the transmission system, thereby driving the moving contact to move toward the closing position. During the process of the moving contact moving toward the closing position, the piston moves toward the side where the stationary arc contact is located, and the volume of the compressed air chamber increases. Under the action of pressure difference, the clean gas in the grounding shell enters the jet chamber and enters the compressed air chamber through the jet hole.

[0033] Of course, the above description is not limited to the examples above. Technical features not described in this invention can be implemented by or using existing technology, and will not be repeated here. The above embodiments and drawings are only used to illustrate the technical solutions of this invention and are not intended to limit this invention. This invention has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention do not depart from the spirit of this invention and should also fall within the scope of protection of the claims of this invention.

Claims

1. A three-phase common-enclosure type fast grounding switch based on clean air insulation, comprising a grounding housing, and a moving contact and a stationary arc contact disposed within the grounding housing, characterized in that: It also includes a movable contact seat fixed inside the grounding housing by an insulating connecting plate. The inner wall of the movable contact seat is sealed and slidably connected to a piston that is fixed to the movable contact. A pull rod extending from the movable contact seat in a direction away from the movable contact is fixedly connected to the piston. A through hole is opened at the end of the movable contact seat away from the movable contact and is sealed and slidably connected to the pull rod. The pull rod is connected to the output shaft of the spring mechanism through a transmission system. A compressed air chamber is formed between the inner wall of the pull rod and the moving contact seat and the piston. A blind hole is provided in the pull rod, which extends to the inner hole of the moving contact. The side wall of the blind hole is in sealed contact with the side wall of the moving contact. The blind hole and the inner hole of the moving contact form a jet chamber. A jet hole is provided on the side wall of the blind hole, which connects the compressed air chamber and the jet chamber. The jet hole is located on the side of the piston facing the compressed air chamber. The piston has an axially penetrating inner hole. The inner hole wall of the piston has a first support platform and a second support platform distributed sequentially along the axial direction. The outer wall of the moving contact is fixed with a clamping platform supported on the first support platform. The end of the pull rod facing the moving contact is fixed with a flange plate that is in sealing contact with the moving contact. The flange plate is supported on the second support platform and is fixed to the second support platform by bolts. The outer circular surface of the piston is fixedly provided with a watch strap contact finger, which is slidably connected to the inner wall of the moving contact seat. A guide ring is also sleeved and fixed on the outer circular surface of the piston. The moving contact has an inner hole with a nozzle installed, and the inner wall of the nozzle has a number of protrusions arranged at intervals along the circumference.

2. The three-phase common-enclosure fast grounding switch based on clean air insulation according to claim 1, characterized in that: The transmission system includes a transmission shaft rotatably connected to the grounded outer shell, an inner crank arm fixedly mounted on the transmission shaft, and a linkage mechanism connecting the transmission shaft and the output shaft of the spring mechanism. Two opposing fork plates are fixedly provided at the end of the inner crank arm away from the transmission shaft. The two fork plates are rotatably connected to sliders by pins, and the two sliders are located on opposite sides of the two fork plates. An insulating joint is fixed to the end of the pull rod away from the moving contact, and a metal joint is fixed to the end of the insulating joint away from the pull rod. The metal joint is located between the two fork plates, and a groove adapted to the slider is opened on the side of the metal joint. The length direction of the groove is consistent with the radial direction of the metal joint and perpendicular to the axial direction of the pin.

3. The three-phase common-enclosure fast grounding switch based on clean air insulation according to claim 2, characterized in that: The linkage mechanism includes an outer crank arm of the main body fixed to the drive shaft, and an outer crank arm of the mechanism fixed to the output shaft of the spring mechanism. A transmission link is hinged to the end of the outer crank arm of the mechanism away from the output shaft of the spring mechanism. The end of the transmission link away from the outer crank arm of the mechanism is hinged to the end of the outer crank arm of the main body away from the drive shaft. The plane containing the outer crank arm of the main body, the transmission link, and the outer crank arm of the mechanism is perpendicular to the axis of the drive shaft and the output shaft of the spring mechanism.

4. The three-phase common-enclosure fast grounding switch based on clean air insulation according to claim 2, characterized in that: A guide rod is also fixed inside the grounding housing. The guide rod passes downward through a metal joint, and the metal joint is slidably connected to the guide rod.

5. The three-phase common-enclosure fast grounding switch based on clean air insulation according to claim 3, characterized in that: A partition is fixedly installed in the inner hole of the pull rod. A blind hole is formed on the side of the partition facing the moving contact, and a hollow cavity is formed on the other side of the partition. The insulating joint extends into the hollow cavity and is connected to the inner wall of the hollow cavity by threads. The end of the insulating joint away from the pull rod extends into the metal joint and is connected to the metal joint by threads. The insulating joint has a through hole with a diameter larger than the outer diameter of the pull rod.

6. The three-phase common-enclosure fast grounding switch based on clean air insulation according to claim 1, characterized in that: The insulating connecting plate is fixed with three movable contact seats, which are arranged in a straight line. The pull rods corresponding to the three movable contact seats are connected to the output shaft of the spring mechanism through the same transmission system.

7. A method of using the three-phase common-enclosure type fast grounding switch based on clean air insulation as described in any one of claims 1 to 6, characterized in that: a. When the circuit is opened, the output shaft of the spring mechanism drives the pull rod away from the stationary arc contact through the transmission system, thereby driving the moving contact to move towards the open position. During the process of the moving contact moving towards the open position, the piston compresses the volume of the air chamber, so that the clean air in the air chamber enters the air chamber through the air jet hole and is sprayed towards the stationary arc contact, extinguishing the electric arc between the moving contact and the stationary arc contact. b. When closing the circuit, the output shaft of the spring mechanism drives the pull rod to move toward the stationary arc contact through the transmission system, thereby driving the moving contact to move toward the closing position. During the process of the moving contact moving toward the closing position, the piston moves toward the side where the stationary arc contact is located, and the volume of the compressed air chamber increases. Under the action of pressure difference, the clean air in the grounding shell enters the jet chamber and enters the compressed air chamber through the jet hole.

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