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

Abstract

The invention relates to a three-phase common box type fast grounding switch based on clean air insulation and a use method, the three-phase common box type fast grounding switch comprises a grounding shell, a moving contact, a static contact and a moving contact seat, an inner hole of the moving contact seat is in sealed sliding connection with a piston, the piston is fixedly connected with a pull rod, and one end, far away from the moving contact, of the moving contact seat is provided with a through hole in sealed sliding connection with the pull rod; the pull rod is in transmission connection with an output shaft of the spring mechanism through a transmission system; an air compression cavity is formed among the pull rod, the side wall of the moving contact seat and the piston, a blind hole penetrating to an inner hole of the moving contact is formed in the pull rod, the blind hole and the inner hole of the moving contact form an air injection cavity, and an air injection hole communicating the air compression cavity with the air injection cavity is formed in the side wall of the blind hole. The pull rod is used for driving the moving contact and the piston to move synchronously, the piston compresses the volume of the air compression cavity and increases the pressure in the air compression cavity while the moving contact is switched off, the spraying speed of clean air is increased, the arc extinguishing effect is improved, and therefore reliable arc extinguishing with the clean air as an insulating medium is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of rapid earthing switches for gas-insulated switchgear, and in particular to a rapid earthing switch using clean air as an insulating medium, specifically a three-phase common-chamber type rapid earthing switch based on clean air insulation and a method of use. Background Art

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

[0003] In the power grid system, the rapid earthing switch is mainly responsible for closing the short-circuit current and opening and closing the induced current. It can realize the rapid grounding of the busbar or cable. It is a safety device for protection and maintenance and plays a very important role in the power grid system.

[0004] The vast majority of existing GIS equipment uses SF6 gas as its 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 development and application of environmentally friendly gas power equipment is a key technical direction for achieving the "dual carbon" goals of the power system. Among these, electrical equipment using clean air as its insulating medium offers the most significant environmental benefits. However, clean air's insulation and arc-extinguishing capabilities are inferior to those of SF6 gas. The arc-extinguishing components of existing fast-acting earthing switches cannot meet the arc-extinguishing requirements of clean air as the insulating medium. Summary of the Invention

[0005] In view of the deficiencies in the prior art, the present invention provides a three-phase common box type fast earthing switch based on clean air insulation and a method of use, which meets the arc extinguishing requirement of using clean air as the insulating medium.

[0006] The present invention is achieved through the following technical scheme, which provides a three-phase common-box type fast grounding switch based on clean air insulation, including a grounding shell, and a moving contact and a static arc contact arranged in the grounding shell, and also including a moving contact seat fixed in the grounding shell through an insulating connecting plate, the inner hole wall of the moving contact seat is sealed and slidably connected with a piston fixed to the moving contact, the piston is fixed with a pull rod extending from the moving contact seat in a direction away from the moving contact, and the end of the moving contact seat away from the moving contact is provided with a through hole sealed and slidably connected with the pull rod; the pull rod is transmission-connected to the output shaft of the 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 is provided in the pull rod, which passes through the inner hole of the moving contact, the side wall of the blind hole is in sealing contact with the side wall of the moving contact, the blind hole and the inner hole of the moving contact form a jet chamber, the side wall of the blind hole is provided with a jet hole connecting the compressed air chamber and the jet chamber, and the jet hole is located on the side of the piston facing the compressed air chamber. During the opening process of the grounding switch of this solution, 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. The clean air in the compressed air chamber enters the jet chamber through the jet hole and is ejected through the moving contact toward one end of the static arc contact, extinguishing the arc generated when the moving contact and the static arc contact are separated, thereby improving the arc extinguishing effect.

[0007] As an optimization, the piston is provided with an axially extending inner hole, and the inner hole wall of the piston is provided with a first support platform and a second support platform distributed in sequence along the axial direction. The outer wall of the movable contact is fixed with a clamping platform supported by the first support platform, and the end of the pull rod facing the movable contact is fixed with a flange plate in sealing contact with the movable contact. The flange plate is supported by the second support platform and is fixed to the second support platform by bolts. This optimization solution not only realizes the integral connection of the pull rod, movable contact, and piston, but also utilizes the flange plate to compress and secure the movable contact while the pull rod is fixed to the piston, eliminating the need for additional fixing bolts for the movable contact, ensuring the integrity of the movable contact, and facilitating improved sealing between the pull rod and the movable contact.

[0008] As an optimization, the outer surface of the piston is fixed with a watchband contact finger, which is slidably connected to the hole wall of the inner hole of the moving contact seat. This optimization solution ensures flow between the piston and the moving contact seat by providing the watchband contact finger.

[0009] As an optimization, a nozzle is installed in the inner hole of the moving contact, and the inner wall of the nozzle is fixed with a plurality of protrusions arranged at intervals along the circumference. This optimization solution 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 internal crank arm fixedly mounted on the transmission shaft, and a connecting rod mechanism connecting the transmission shaft to the output shaft of the spring mechanism. The internal crank arm is fixedly provided with two oppositely disposed fork plates at one end away from the transmission shaft. The two fork plates are respectively rotatably connected to sliders via pins, and the two sliders are located on opposite sides of the two fork plates. The end of the pull rod away from the moving contact is fixedly connected to an insulating joint. The end of the insulating joint away from the pull rod is fixedly connected to a metal joint. The metal joint is located between the two fork plates, and a side surface of the metal joint is provided with a slide groove adapted to fit the slider. The length direction of the slide groove is consistent with the radial direction of the metal joint and is perpendicular to the axial direction of the pin. When the transmission system of this optimized solution is in use, the output shaft of the spring mechanism drives the transmission shaft to rotate through the connecting rod mechanism, thereby driving the internal crank arm to rotate. When the internal crank arm rotates, force is transmitted through the slider, driving the pull rod to move along its axial direction. The provided slide groove allows the slider to slide in the slide groove, displacing relative to the metal joint to avoid interfering with the rotation of the internal crank arm.

[0011] As an optimization, the connecting rod mechanism includes a main body external crank arm fixedly connected to the transmission shaft, and a mechanism external crank arm fixedly connected to the output shaft of the spring mechanism. The end of the mechanism external crank arm remote from the spring mechanism output shaft is hingedly connected to a transmission connecting rod. The end of the transmission connecting rod remote from the mechanism external crank arm is hingedly connected to the end of the main body external crank arm remote from the transmission shaft. The plane in which the main body external crank arm, the transmission connecting rod, and the mechanism external crank arm lie is perpendicular to the axis of the transmission shaft and the spring mechanism output shaft. This optimized connecting rod mechanism has a simple structure, reliable transmission, and reduces manufacturing cost and difficulty.

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

[0013] As an optimization, a partition is fixedly provided in the inner hole of the pull rod. The blind hole is formed on the side of the partition facing the moving contact, and a hollow chamber is formed on the other side of the partition. The insulating joint extends into the hollow chamber and is connected to the inner wall of the hollow chamber by a thread. The end of the insulating joint away from the pull rod extends into the metal joint and is connected to the metal joint by a thread. The insulating joint is provided with a through hole with a diameter greater than the outer diameter of the pull rod. This optimization solution forms a hollow chamber by providing a partition, which not only reduces the weight of the pull rod, but also facilitates detachable connection with the insulating joint by thread. At the same time, it provides an accessible space for the guide rod, allowing the guide rod to extend into the inner hole of the insulating joint and the hollow chamber, which is conducive to increasing the guiding distance of the guide rod.

[0014] As an optimization, the insulating connecting plate is fixedly provided with three movable contact seats, 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 via a common transmission system. This optimized arrangement achieves three-phase co-existence and ensures the synchronization of the movement of the corresponding movable contacts of the three movable contact seats.

[0015] This solution also provides a method for using a three-phase common box type fast earthing switch based on clean air insulation, including the following aspects: a. When opening, the output shaft of the spring mechanism drives the pull rod away from the static arc contact through the transmission system, thereby driving the moving contact to the opening position. During the movement of the moving contact to the opening position, the piston compresses the volume of the air pressure chamber, allowing the clean air in the air pressure chamber to enter the air injection chamber through the air injection hole and be ejected toward the static arc contact, extinguishing the arc between the moving contact and the static arc contact; b. When closing the circuit breaker, the output shaft of the spring mechanism drives the pull rod toward the static arc contact through the transmission system, thereby driving the moving contact to move toward the closed position. During the movement of the moving contact toward the closed position, the piston moves toward the side where the static arc contact is located, and the volume of the compressed air chamber increases. Under the action of the pressure difference, the clean gas in the grounded shell enters the jet chamber and enters the compressed air chamber through the jet hole.

[0016] The beneficial effects of the present invention are as follows: the pull rod is used to drive the moving contact and the piston to move synchronously. When the moving contact is opened, the piston compresses the volume of the pressure chamber, increases the pressure in the pressure chamber, increases the clean air ejection speed, and improves the arc extinguishing effect, thereby realizing reliable arc extinguishing using clean air as the insulating medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the open state of the rapid grounding switch of the present invention; Figure 2 This is a schematic diagram of the fast grounding switch of the present invention in the closed state; Figure 3 Schematic diagram of the transmission system structure of the present invention; Figure 4 Schematic diagram of the structure of the moving contact unit; Figure 5 Schematic diagram of the structure of the static contact unit; Figure 6 It is a schematic diagram of the connection between the slider and the metal joint; As shown in the figure: 1. Grounding shell, 2. Spring mechanism, 3. Transmission system, 4. Moving contact unit, 5. Static contact unit, 6. Grounding handle, 7. Grounding copper busbar, 8. Jet hole, 31. Mechanism outer crank arm, 32. Transmission connecting rod, 33. Body outer crank arm, 34. Transmission shaft, 35. Body inner crank arm, 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. Strap contact finger, 48. Moving contact, 49. Nozzle, 51. Static arc contact, 52. Shielding cover, 53. Contact piece, 54. Spring contact finger, 55. Static contact seat. DETAILED DESCRIPTION

[0018] In order to clearly illustrate the technical features of this solution, this solution is described below through specific implementation methods.

[0019] like Figure 1 and 2 The three-phase common box type fast grounding switch based on clean air insulation is shown, including a grounding shell 1, and a moving contact 48 and a static arc contact 51 arranged in the grounding shell 1. The grounding shell is filled with clean air. The grounding shell 1 is fixed to the extraction port of the three-station unit, providing structural support and gas sealing. The moving contact and the static arc contact are both existing technologies. The moving contact adopts a copper tube structure and belongs to the moving contact unit 4. The moving contact has an inner hole extending axially therethrough. The static arc contact belongs to the static contact unit 5. Figure 5 As shown, the static contact unit 5 also includes a shielding cover 52, a contact piece 53, a spring contact finger 54 and a static contact seat 55. The static contact seat 55 is connected to the main circuit by bolts, the static arc contact 51 is fastened to the static contact seat 55 by threads and screws, and the contact piece 53 is fastened to the static contact seat 55 by the spring contact finger 54. The shielding cover 52 is installed on the outside to improve the electric field.

[0020] The clean air-insulated, three-phase, common-chamber, rapid earthing switch of this embodiment also includes a movable contact seat 45 secured within the grounding housing via an insulating connecting plate 38. The movable contact seat 45 is assembled and connected to a grounding handle 6 secured to the grounding housing via a grounding copper busbar 7. A piston 46, secured to the movable contact, is sealed and slidingly engaged with the inner bore wall of the movable contact seat. A pull rod 44, extending away from the movable contact, is secured to the piston 46. A through-hole is provided at the end of the movable contact seat away from the movable contact, which is sealed and slidingly engaged with the pull rod. A sealing ring 43 is provided between the through-hole wall and the pull rod to enhance the sealing effect of the compressed air chamber. The pull rod of this embodiment is an iron rod. The movable contact of this embodiment is located above the static arc contact. The movable contact seat is a shell structure with an open lower end. The through-hole is provided in the center of the top plate of the movable contact seat. The pull rod, piston, and movable contact seat are coaxially arranged.

[0021] The pull rod is connected to the output shaft of the spring mechanism 2 via a transmission system 3. The spring mechanism 2 also utilizes existing technology, providing power to the pull rod's movement to achieve opening and closing actions. In this embodiment, three movable contact seats are fixedly mounted on the insulating connecting plate, forming a three-phase common box structure. 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 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 and passes through the inner hole of the moving contact. The side wall of the blind hole is in sealing 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. The side wall of the blind hole is provided with a plurality of air jet holes 8 connecting the compressed air chamber and the air jet chamber, and the air jet holes are located on the side of the piston facing the compressed air chamber. In this embodiment, the air jet holes are arranged above the piston, and the air jet holes are arranged in upper and lower layers, and the air jet holes in each layer are evenly distributed along the circumference. The piston is provided with an inner hole which passes through in the axial direction, and the inner hole wall of the piston is provided with a first support platform and a second support platform distributed in sequence along the axial direction. The upper end of the outer wall of the moving contact is fixed with a clamping platform 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 which is in sealing contact with the moving contact. The upper end of the moving contact is pressed against the lower end face of the flange plate to better achieve sealing. 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 abutting seal is formed between the moving contact and the flange plate.

[0023] A band contact finger 47 is fixedly provided on the outer circumferential surface of the piston. The band contact finger 47 is slidably connected to the hole wall of the inner hole of the moving contact seat to ensure flow between the piston 46 and the moving contact seat 45.

[0024] A guide ring 40 is also fixedly mounted on the outer circumference of the piston. When the moving contact, piston and pull rod perform opening and closing movements as a whole, the guide ring 40 plays a guiding and sealing role, which is conducive to further building up the air pressure in the compressed air chamber.

[0025] The inner hole of the moving contact 48 is provided with a nozzle 49 , and the inner wall of the nozzle 49 is provided with a plurality of protrusions spaced apart along the circumferential direction. The protrusions reduce the cross-sectional area through which the air flows, thereby facilitating the increase of 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 internal crank arm 35 fixedly mounted on the transmission shaft 34, and a connecting rod mechanism connecting the transmission shaft to the output shaft of the spring mechanism. The internal crank arm 35 is fixedly mounted on the end away from the transmission shaft with two opposing fork plates. The two fork plates are rotatably connected to sliders 36 via pins, and the two sliders are located on opposite sides of the fork plates. The pins are rotatably connected to the fork plates, and the pins and sliders can be rotatably or fixedly connected. An insulating joint 42 is fixedly mounted on the end of the pull rod 44 away from the moving contact. A metal joint 41 is fixedly mounted on the end of the insulating joint away from the pull rod. The metal joint is located between the two fork plates, and a slot is defined on the side of the metal joint to accommodate the slider. The slot's length aligns with the radial direction of the metal joint and is perpendicular to the axial direction of the pin. The length direction of the slide is perpendicular to the movement direction of the pull rod. When the crank arm in the main body rotates, the force is transmitted through the slider, driving the pull rod to move along its axial direction. Through the set slide, the slider can be displaced laterally relative to the metal joint to avoid interfering with the rotation of the crank arm in the main body.

[0027] The connecting rod mechanism of this embodiment includes a main body outer crank arm 33 fixedly connected to the transmission shaft, and a mechanism outer crank arm 31 fixedly connected to the output shaft of the spring mechanism. The end of the mechanism outer crank arm 31 away from the output shaft of the spring mechanism is hinged with a transmission connecting rod 32, and the end of the transmission connecting rod 32 away from the mechanism outer crank arm 31 is hinged to the end of the main body outer crank arm 33 away from the transmission shaft. The plane where the main body outer crank arm 33, the transmission connecting rod 32 and the mechanism outer crank arm 31 are located is perpendicular to the axis of the transmission shaft and the output shaft of the spring mechanism.

[0028] A guide rod 37 is further fixed in the grounding shell of this embodiment. The upper end of the guide rod 37 is connected to the grounding shell by a thread. The guide rod 37 passes downward through a metal joint, and the metal joint is slidably connected to the guide rod. A guide hole adapted to the guide rod is opened on the metal joint.

[0029] A partition is fixedly provided in the inner hole of the pull rod. The blind hole is formed on the side of the partition facing the movable contact, and a hollow chamber is formed on the other side of the partition. In this embodiment, the blind hole is located below the partition, and the hollow chamber is located above the partition. The insulating joint extends downward into the hollow chamber and is connected to the inner wall of the hollow chamber via a threaded connection. The end of the insulating joint away from the pull rod extends into the metal joint and is connected to the metal joint via a threaded connection. In this embodiment, the upper end of the insulating joint is threadedly connected to the metal joint. A through hole with a diameter larger than the outer diameter of the pull rod is provided in the insulating joint. The inner hole of the insulating joint is connected to the hollow chamber. The diameter of the hollow chamber is also larger than the outer diameter of the pull rod to accommodate the guide rod and increase the guide movement distance.

[0030] The method for using the three-phase common box type fast earthing switch based on clean air insulation in this embodiment is as follows: a. When opening the circuit breaker, the output shaft of the spring mechanism drives the pull rod to move away from the static arc contact through the transmission system, thereby driving the moving contact to move toward the opening position. During the movement of the moving contact toward the opening position, the piston compresses the volume of the air compression chamber, so that the clean air in the air compression chamber enters the air injection chamber through the air injection hole and is ejected toward the static arc contact. The blocking effect of the air injection hole further accelerates the gas, forming a high-speed air blow, which quickly extinguishes the arc between the moving contact and the static arc contact.

[0031] The transmission system drives the pull rod to move away from the static arc contact, which means that the connecting rod mechanism transmits the power released by the output shaft of the spring mechanism to the transmission shaft, drives the transmission shaft to rotate clockwise, and the transmission shaft drives the crank arm in the body to rotate clockwise. The force transmitted by the slider is used to pull the pull rod upward to achieve opening.

[0032] b. When closing the circuit breaker, the output shaft of the spring mechanism drives the pull rod toward the static arc contact through the transmission system, thereby driving the moving contact to move toward the closed position. During the movement of the moving contact toward the closed position, the piston moves toward the side where the static arc contact is located, and the volume of the compressed air chamber increases. Under the action of the pressure difference, the clean gas in the grounded 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 above examples. Technical features not described in the present invention can be achieved by or by adopting existing technologies, which will not be described here. The above embodiments and drawings are only used to illustrate the technical solutions of the present invention and are not limitations of the present invention. The present invention is described in detail with reference to the preferred implementation methods. Ordinary technicians in this field should understand that changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention do not depart from the purpose of the present invention and should also fall within the scope of protection of the claims of the present invention.

Claims

1. A three-phase common box type fast grounding switch based on clean air insulation, comprising a grounding shell (1), and a moving contact (48) and a static arc contact (51) arranged in the grounding shell (1), characterized in that: It also includes a movable contact seat (45) fixed in the grounded housing via an insulating connecting plate (38), the inner hole wall of the movable contact seat is sealed and slidably connected to a piston (46) fixed to the movable contact, the piston (46) is fixedly connected to a pull rod (44) extending from the movable contact seat in a direction away from the movable contact, and the end of the movable contact seat away from the movable contact is provided with a through hole 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 (3); A compressed air chamber is formed between the pull rod (44), the side wall of the movable contact seat and the piston. A blind hole is provided in the pull rod and passes through the inner hole of the movable contact. The side wall of the blind hole is in sealing contact with the side wall of the movable contact. The blind hole and the inner hole of the movable contact form an air jet chamber. The side wall of the blind hole is provided with an air jet hole (8) connecting the compressed air chamber and the air jet chamber, and the air jet hole is located on the side of the piston facing the compressed air chamber.

2. The three-phase common box type fast earthing switch based on clean air insulation according to claim 1 is characterized in that: The piston is provided with an inner hole which passes through in the axial direction, and the inner hole wall of the piston is provided with a first support platform and a second support platform which are distributed in sequence in the axial direction. The outer wall of the moving contact is fixed with a clamping platform supported on the first support platform, and the end of the pull rod facing the moving contact is fixed with a flange plate which is in sealing contact with the moving contact, and the flange plate is supported on the second support platform and is fixed to the second support platform by bolts.

3. The three-phase common box type fast earthing switch based on clean air insulation according to claim 1 is characterized in that: A watchband contact finger (47) is fixedly provided on the outer cylindrical surface of the piston, and the watchband contact finger (47) is slidably connected to the hole wall of the inner hole of the moving contact seat.

4. The three-phase common box type fast earthing switch based on clean air insulation according to claim 1 is characterized in that: The inner hole of the moving contact (48) is provided with a nozzle (49), and the inner wall of the nozzle (49) is provided with a plurality of protrusions arranged at intervals along the circumferential direction.

5. The three-phase common box type fast earthing switch based on clean air insulation according to claim 1 is characterized in that: The transmission system (3) includes a transmission shaft (34) rotatably connected to the grounded housing (1), a body inner crank arm (35) fixedly mounted on the transmission shaft (34), and a connecting rod mechanism connecting the transmission shaft and the output shaft of the spring mechanism, wherein the body inner crank arm (35) is fixedly provided with two oppositely arranged fork plates at one end away from the transmission shaft, and the two fork plates are respectively rotatably connected to sliders (36) via pins, and the two sliders (36) are located on opposite sides of the two fork plates; An insulating joint (42) is fixedly connected to one end of the pull rod (44) away from the moving contact, and a metal joint (41) is fixedly connected to one end of the insulating joint away from the pull rod. The metal joint is located between the two fork plates, and a sliding groove adapted to the slider is provided on the side of the metal joint. The length direction of the sliding groove is consistent with the radial direction of the metal joint and is perpendicular to the axial direction of the pin shaft.

6. The three-phase common box type fast earthing switch based on clean air insulation according to claim 5 is characterized in that: The connecting rod mechanism comprises a body outer crank arm (33) fixedly connected to the transmission shaft, and a mechanism outer crank arm (31) fixedly connected to the output shaft of the spring mechanism, an end of the mechanism outer crank arm (31) away from the output shaft of the spring mechanism is hingedly connected to a transmission connecting rod (32), an end of the transmission connecting rod (32) away from the mechanism outer crank arm (31) is hingedly connected to an end of the body outer crank arm (33) away from the transmission shaft, and a plane where the body outer crank arm (33), the transmission connecting rod (32) and the mechanism outer crank arm (31) are located is perpendicular to the axis of the transmission shaft and the output shaft of the spring mechanism.

7. The three-phase common box type fast earthing switch based on clean air insulation according to claim 5 is characterized in that: A guide rod is also fixedly provided in the grounding shell. The guide rod passes downward through the metal joint, and the metal joint is slidably connected to the guide rod.

8. The three-phase common box type fast earthing switch based on clean air insulation according to claim 6 is characterized in that: A partition is fixedly provided in the inner hole of the pull rod, and the blind hole is formed on the side of the partition facing the moving contact, and a hollow chamber is formed on the other side of the partition. The insulating joint extends into the hollow chamber and is threadedly connected to the inner wall of the hollow chamber. The insulating joint extends into the metal joint at one end away from the pull rod and is threadedly connected to the metal joint. A through hole with a diameter larger than the outer diameter of the pull rod is provided in the insulating joint.

9. The three-phase common box type fast earthing 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.

10. A method for using the three-phase common box type fast earthing switch based on clean air insulation according to any one of claims 1 to 9, characterized in that: a. When opening, the output shaft of the spring mechanism drives the pull rod away from the static arc contact through the transmission system, thereby driving the moving contact to the opening position. During the movement of the moving contact to the opening position, the piston compresses the volume of the air pressure chamber, allowing the clean air in the air pressure chamber to enter the air injection chamber through the air injection hole and be ejected toward the static arc contact, extinguishing the arc between the moving contact and the static arc contact; b. When closing the circuit breaker, the output shaft of the spring mechanism drives the pull rod toward the static arc contact through the transmission system, thereby driving the moving contact to move toward the closed position. During the movement of the moving contact toward the closed position, the piston moves toward the side where the static arc contact is located, and the volume of the compressed air chamber increases. Under the action of the pressure difference, the clean gas in the grounded shell enters the jet chamber and enters the compressed air chamber through the jet hole.

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