Miniaturized environment-friendly gas insulation switch cabinet

Abstract

The utility model provides a miniaturized environment-friendly gas insulation switch cabinet which comprises a switch cabinet body, a gas box and a cable chamber which are distributed up and down are arranged on the inner side of the rear portion of the switch cabinet body, first environment-friendly gas is filled in the gas box, a sealed pole type vacuum circuit breaker chamber is fixed in the gas box, and a second environment-friendly gas is filled in the sealed pole type vacuum circuit breaker chamber. The outer top of the rear side of the switch cabinet body is fixedly provided with a box cylinder type fully-sealed three-station isolation switch, the interior of the box cylinder type fully-sealed three-station isolation switch is filled with second environment-friendly gas, and the wire inlet end of a vacuum circuit breaker in the sealed pole type vacuum circuit breaker chamber is electrically connected with the wire outlet end of the box cylinder type fully-sealed three-station isolation switch. The wire outlet end of the vacuum circuit breaker is connected with the side wall of the cable chamber through an insulating sleeve. A cable in the cable chamber penetrates through the insulating sleeve and then is electrically connected with the wire outlet end of the vacuum circuit breaker. According to the utility model, the purposes of full sealing and miniaturization can be realized.

Description

Technical Field

[0001] This utility model relates to the field of switchgear technology, and more specifically, to a miniaturized, environmentally friendly gas-insulated switchgear. Background Technology

[0002] Gas-insulated switchgear is a fully enclosed gas-insulated electrical device, including circuit breakers, disconnecting switches, grounding switches, instrument transformers, surge arresters, busbars, connectors, and outgoing terminals. All these components are enclosed in a metal-grounded cabinet, which is filled with insulating gas at a certain pressure.

[0003] In recent years, with the development of urban power grid construction and renovation, rail transit, and large industrial and mining enterprises in my country, new and higher requirements have been put forward for switchgear, including miniaturization, intelligence, maintenance-free operation, and all-condition compatibility. Traditional air-insulated switchgear, limited by environmental conditions (such as high altitude, humidity, salt spray, pollution, and corrosion), can no longer meet the requirements of users in metallurgy, petrochemicals, mining, and coastal areas. In urban subways and light rail, high-rise buildings, and large enterprises, traditional air-insulated switchgear is also no longer suitable due to space constraints. Gas-insulated switchgear, due to its fully enclosed and gas-insulated design, is suitable for any environmental conditions. Furthermore, its advantages, such as small size, light weight, high safety, high reliability, and adaptability to harsh environmental conditions, have led to its rapid promotion and application in my country.

[0004] However, most of the existing 24-35kV gas-insulated switchgear on the market adopts a low-pressure box-type structure, with a large isolation break and a large distance to ground insulation, resulting in a large switchgear size, which is difficult to replace the current SF6 gas-insulated switchgear. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a miniaturized and environmentally friendly gas-insulated switchgear that can achieve the purpose of full sealing and miniaturization.

[0006] This utility model provides a miniaturized environmentally friendly gas-insulated switchgear, including a switchgear cabinet. A gas box and a cable compartment are arranged vertically on the inner rear side of the switchgear cabinet. The gas box is filled with a first environmentally friendly gas. A sealed pole-type vacuum circuit breaker compartment is fixed inside the gas box. A box-type fully sealed three-position disconnector is fixed on the outer top of the rear side of the switchgear cabinet. The box-type fully sealed three-position disconnector is filled with a second environmentally friendly gas. The input terminal of the vacuum circuit breaker in the sealed pole-type vacuum circuit breaker compartment is electrically connected to the output terminal of the box-type fully sealed three-position disconnector. The output terminal of the vacuum circuit breaker is connected to the side wall of the cable compartment through an insulating sleeve. The cable in the cable compartment passes through the insulating sleeve and is electrically connected to the output terminal of the vacuum circuit breaker. The operating terminal of the vacuum circuit breaker is drive-connected to the vacuum circuit breaker operating mechanism located inside the front side of the switchgear cabinet. The box-type fully sealed three-position disconnector is drive-connected to the three-position operating mechanism located inside the front side of the switchgear cabinet.

[0007] This utility model, by adopting a box-type fully sealed three-position disconnecting switch and placing the sealed pole-type vacuum circuit breaker chamber in a gas box filled with a first environmentally friendly gas, and by placing the vacuum circuit breaker in the sealed pole-type vacuum circuit breaker chamber, enables the gas-insulated switchgear to achieve full sealing and miniaturization. Moreover, the size of this utility model can be consistent with that of SF6 gas-insulated switchgear, and it can completely replace SF6 gas-insulated switchgear.

[0008] In one possible implementation, the box-type fully sealed three-position disconnect switch includes a box-type housing, a transmission assembly, a grounding stationary contact, a first isolating stationary contact, a second isolating stationary contact, and a conductive element. The grounding stationary contact, the first isolating stationary contact, and the second isolating stationary contact are sequentially and spaced apart on the side wall of the box-type housing along the axial direction and are circumferentially sealed to the box-type housing. The conductive ends of the grounding stationary contact, the first isolating stationary contact, and the second isolating stationary contact all extend into the interior of the box-type housing and are coaxially arranged with the box-type housing. The conductive element is axially movable and embedded in the conductive end of the first isolating stationary contact. The three-position operating mechanism is fixed to the outer wall of the box-type housing. The transmission assembly is rotatable and circumferentially sealed and connected to one end of the box-type housing. The outer end of the transmission assembly is connected to the drive end of the three-position operating mechanism. The conductive component is connected to the inner end of the transmission assembly via a dynamic connection. A three-position operating mechanism drives the conductive component to move axially along the cylindrical housing, enabling the fully sealed three-position disconnect switch to operate in grounding, isolation, or conduction modes. A second environmentally friendly gas is introduced into the cylindrical housing, and the input terminal of the vacuum circuit breaker is electrically connected to the output terminal of the second isolating stationary contact. By enclosing the conductive ends of the grounding stationary contact, the first isolating stationary contact, and the second isolating stationary contact within the cylindrical housing, and by introducing a second environmentally friendly gas into the cylindrical housing, the insulation distance between the first isolating stationary contact and the grounding stationary contact, as well as the insulation distance between the first isolating stationary contact and the second isolating stationary contact, can be reduced. This results in a smaller size and lower production and material costs for the fully sealed three-position disconnect switch.

[0009] In one possible implementation, the box-type fully sealed three-position disconnect switch further includes a lead screw, one end of which is drivenly connected to the inner end of a transmission assembly. The conductive element has a ring-shaped structure, with an insulating connecting sleeve embedded at one end. The other end of the lead screw passes through the insulating connecting sleeve and is threadedly connected to it. When the motor in the three-position operating mechanism drives the lead screw to rotate via the transmission assembly, the lead screw drives the conductive element to move along the axial direction of the box-type housing via the insulating connecting sleeve, thereby enabling the box-type fully sealed three-position disconnect switch to operate in grounding, isolation, or conduction modes. With this structure, when the motor in the three-position operating mechanism drives the lead screw to rotate via the transmission assembly, the lead screw can drive the conductive element to move along the axial direction of the box-type housing via the insulating connecting sleeve. When the conductive element moves towards... When one side of the grounding stationary contact moves to make the conductive end of the first isolating stationary contact connected to the conductive end of the grounding stationary contact through the conductive element, the three-position disconnecting switch can operate in grounding mode; when the conductive element moves to the middle position and disengages from both the conductive ends of the grounding stationary contact and the second isolating stationary contact, the three-position disconnecting switch can operate in isolation mode; when the conductive element moves to one side of the second isolating stationary contact to make the conductive ends of the first isolating stationary contact connected to the conductive ends of the second isolating stationary contact through the conductive element, the three-position disconnecting switch can operate in conduction mode; the operating state of the three-position disconnecting switch can be controlled by controlling the movement position of the conductive element through the three-position operating mechanism, which has the advantage of convenient control; in addition, the insulation between the conductive element and the lead screw is achieved by the insulating connecting sleeve.

[0010] In one possible implementation, a limiting groove is axially provided on the outer wall of the conductive component, and at least one limiting pin is fixed on the side wall of the conductive end of the first isolating stationary contact. The inner end of the limiting pin is inserted into the limiting groove and can slide along the length direction of the limiting groove when the conductive component moves. By adopting this structure, the circumferential limiting of the conductive component and the conductive end of the first isolating stationary contact can be achieved under the cooperation of the limiting pin and the limiting groove. This prevents the conductive component from rotating with the lead screw when the lead screw rotates, thereby ensuring that the lead screw can reliably drive the conductive component to move relative to the conductive end of the first isolating stationary contact.

[0011] In one possible implementation, two limiting pins are fixed on the side wall of the conductive end of the first isolating stationary contact. The two limiting pins are spaced apart along the axial direction of the conductive end of the first isolating stationary contact. The inner ends of the two limiting pins are inserted into the limiting grooves and can slide along the length direction of the limiting grooves when the conductive component moves. By adopting this structure, under the action of the two limiting pins, the circumferential limiting effect on the conductive component and the conductive end of the first isolating stationary contact can be further realized. Moreover, the two limiting pins can further guide the movement of the conductive component relative to the conductive end of the first isolating stationary contact, so as to improve the reliability of the movement of the conductive component relative to the conductive end of the first isolating stationary contact.

[0012] In one possible implementation, the transmission assembly includes a drive shaft and a rotary seal. The rotary seal is fixed to one end of the cylindrical housing and circumferentially seals the housing. The drive shaft is rotatably inserted through the rotary seal and circumferentially seals it. The outer end of the drive shaft is connected to the drive end of the three-position operating mechanism. One end of the lead screw is axially fixed to and connected to the inner end of the drive shaft. With this structure, under the action of the rotary seal, the drive shaft can be reliably rotatably connected to one end of the cylindrical housing and circumferentially sealed to the housing. The lead screw can also be reliably connected to the drive end of the three-position operating mechanism via the drive shaft. Additionally, the outer end of the drive shaft can be connected to the drive end of the three-position operating mechanism via a transmission component such as a chain assembly.

[0013] In one possible implementation, the second environmentally friendly gas is compressed air or nitrogen, and the pressure of the environmentally friendly gas filled inside the cylindrical housing is not less than 0.5 MPa. By using compressed air or nitrogen as the second environmentally friendly gas, there are environmental advantages. Since the pressure of the environmentally friendly gas filled inside the cylindrical housing is not less than 0.5 MPa, the insulation distance between the first isolating stationary contact and the grounding stationary contact can be reduced, as can the insulation distance between the first isolating stationary contact and the second isolating stationary contact. This results in a smaller size and lower production and material costs for the three-position disconnect switch.

[0014] In one possible implementation, the first environmentally friendly gas is compressed air or nitrogen; by using compressed air or nitrogen as the first environmentally friendly gas, there are environmental advantages.

[0015] In one possible implementation, a secondary instrument compartment is provided on the top of the front side of the switchgear cabinet. Through the secondary instrument compartment, the controller in the secondary instrument compartment can realize the control and electrical operation of the switchgear, such as the control of the three-position operating mechanism and the vacuum circuit breaker operating mechanism. When the controller controls the three-position operating mechanism, it can switch the three-position disconnecting switch between grounding mode, isolation mode and conduction mode. When the controller controls the vacuum circuit breaker operating mechanism, the vacuum circuit breaker operating mechanism can realize the closing and opening control of the vacuum circuit breaker in the sealed pole vacuum circuit breaker compartment. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model;

[0017] Figure 2 This is a schematic diagram of a box-type fully sealed three-position disconnect switch. Detailed Implementation

[0018] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of this application and are not intended to limit the scope of protection of the embodiments of this application. Those skilled in the art can make adjustments as needed to adapt to specific application scenarios.

[0019] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0020] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0021] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0022] See Figure 1-2 As shown in the figure, this application discloses a miniaturized environmentally friendly gas-insulated switchgear, including a switchgear cabinet 1. A gas box 11 and a cable compartment 12 are arranged vertically on the inner rear side of the switchgear cabinet 1. The gas box 11 is filled with a first environmentally friendly gas. A sealed pole-type vacuum circuit breaker compartment 2 is fixed inside the gas box 11. A box-type fully sealed three-position disconnect switch 3 is fixed on the outer top of the rear side of the switchgear cabinet 1. The box-type fully sealed three-position disconnect switch 3 is filled with a second environmentally friendly gas. The sealed pole-type vacuum circuit breaker compartment... The incoming terminal of the vacuum circuit breaker in section 2 is electrically connected to the outgoing terminal of the box-type fully sealed three-position disconnector 3. The outgoing terminal of the vacuum circuit breaker is connected to the side wall of the cable compartment 12 through the insulating sleeve 4. The cable in the cable compartment 12 passes through the insulating sleeve 4 and is electrically connected to the outgoing terminal of the vacuum circuit breaker. The operating terminal of the vacuum circuit breaker is driven by the vacuum circuit breaker operating mechanism 5 located inside the front side of the switch cabinet 1. The box-type fully sealed three-position disconnector 3 is driven by the three-position operating mechanism 6 located inside the front side of the switch cabinet 1.

[0023] The box-type fully sealed three-position disconnect switch 3 includes a box-type housing 31, a transmission assembly 32, a grounding stationary contact 33, a first isolating stationary contact 34, a second isolating stationary contact 35, and a conductive element 36. The grounding stationary contact 33, the first isolating stationary contact 34, and the second isolating stationary contact 35 are sequentially and spaced apart on the side wall of the box-type housing 31 along the axial direction and are circumferentially sealed to the box-type housing 31. The conductive ends of the grounding stationary contact 33, the first isolating stationary contact 34, and the second isolating stationary contact 35 all extend into the box-type housing 31 and are coaxially arranged with the box-type housing 31. The conductive element 36 is axially movable and embedded in the conductive end of the first isolating stationary contact 34. The three-position operating mechanism 6 is fixed on the outer wall of the box-type housing 31. The transmission assembly 32 is rotatable and circumferentially sealed to one end of the box-type housing 31. The outer end of the transmission assembly 32 is connected to the three-position operating mechanism 6. The drive end of the three-position operating mechanism 6 is connected to the transmission, and the conductive element 36 is connected to the inner end of the transmission assembly 32. The three-position operating mechanism 6 is used to drive the conductive element 36 to move along the axial direction of the box-type housing 31 so that the box-type fully sealed three-position disconnect switch 3 operates in the grounding, isolation, or conduction mode. The second environmentally friendly gas is filled into the box-type housing 31, and the input end of the vacuum circuit breaker is electrically connected to the output end of the second isolation stationary contact 35. By enclosing the conductive ends of the grounding stationary contact, the first isolation stationary contact, and the second isolation stationary contact in the box-type housing, and filling the box-type housing with the second environmentally friendly gas, the insulation distance between the first isolation stationary contact and the grounding stationary contact, as well as the insulation distance between the first isolation stationary contact and the second isolation stationary contact, can be reduced. This makes the box-type fully sealed three-position disconnect switch smaller in size and lower in production and material costs.

[0024] The box-type fully sealed three-position disconnect switch 3 also includes a lead screw 37, one end of which is connected to the inner end of the transmission assembly 32. The conductive element 36 has a ring-shaped structure, with an insulating connecting sleeve 38 embedded in one end of the conductive element 36. The other end of the lead screw 37 passes through the insulating connecting sleeve 38 and is threadedly connected to the insulating connecting sleeve 38. When the motor in the three-position operating mechanism 6 drives the lead screw 37 to rotate via the transmission assembly 32, the lead screw 37 drives the conductive element 36 to move along the axial direction of the box-type housing 31 via the insulating connecting sleeve 38, so that the box-type fully sealed three-position disconnect switch 3 operates in grounding, isolation, or conduction mode. With this structure, when the motor in the three-position operating mechanism drives the lead screw to rotate via the transmission assembly, the lead screw can drive the conductive element along the axial direction of the box-type housing via the insulating connecting sleeve. Directional movement: When the conductive element moves towards the grounding stationary contact to make the conductive end of the first isolating stationary contact connected to the conductive end of the grounding stationary contact through the conductive element, the three-position disconnecting switch can operate in grounding mode; when the conductive element moves to the middle position and disengages from both the conductive ends of the grounding stationary contact and the second isolating stationary contact, the three-position disconnecting switch can operate in isolation mode; when the conductive element moves towards the second isolating stationary contact to make the conductive end of the first isolating stationary contact connected to the conductive end of the second isolating stationary contact through the conductive element, the three-position disconnecting switch can operate in conduction mode; the operating state of the three-position disconnecting switch can be controlled by controlling the movement position of the conductive element through the three-position operating mechanism, which has the advantage of convenient control; in addition, the insulation between the conductive element and the lead screw is achieved by the insulating connecting sleeve.

[0025] A limiting groove 361 is axially provided on the outer wall of the conductive component 36. At least one limiting pin 39 is fixed on the side wall of the conductive end of the first isolating stationary contact 34. The inner end of the limiting pin 39 is inserted into the limiting groove 361 and can slide along the length direction of the limiting groove 361 when the conductive component 36 moves. With this structure, the circumferential limiting of the conductive component and the conductive end of the first isolating stationary contact can be achieved under the cooperation of the limiting pin and the limiting groove. Thus, when the lead screw rotates, the conductive component can be prevented from rotating with the lead screw, thereby ensuring that the lead screw can reliably drive the conductive component to move relative to the conductive end of the first isolating stationary contact.

[0026] Two limiting pins 39 are fixed on the side wall of the conductive end of the first isolating stationary contact 34. The two limiting pins 39 are spaced apart along the axial direction of the conductive end of the first isolating stationary contact 34. The inner ends of the two limiting pins 39 are inserted into the limiting groove 361 and can slide along the length direction of the limiting groove 361 when the conductive member 36 moves. With this structure, the circumferential limiting effect of the conductive member and the conductive end of the first isolating stationary contact can be further realized under the action of the two limiting pins. The two limiting pins can also play a further guiding role in the movement of the conductive member relative to the conductive end of the first isolating stationary contact, so as to improve the reliability of the movement of the conductive member relative to the conductive end of the first isolating stationary contact.

[0027] The transmission assembly 32 includes a transmission shaft 321 and a rotary seal 322. The rotary seal 322 is fixed to one end of the cylindrical housing 31 and circumferentially seals the cylindrical housing 31. The transmission shaft 321 is rotatably inserted into the rotary seal 322 and circumferentially seals the rotary seal 322. The outer end of the transmission shaft 321 is connected to the drive end of the three-position operating mechanism 6. One end of the lead screw 37 is axially fixed to and connected to the inner end of the transmission shaft 321. With this structure, under the action of the rotary seal, the transmission shaft can be reliably rotatably connected to one end of the cylindrical housing and circumferentially sealed to the cylindrical housing. The lead screw can be reliably connected to the drive end of the three-position operating mechanism through the transmission shaft. In addition, the outer end of the transmission shaft can be connected to the drive end of the three-position operating mechanism through a transmission component such as a chain assembly.

[0028] The second environmentally friendly gas is compressed air or nitrogen, and the pressure of the environmentally friendly gas filled inside the cylindrical housing 31 is not less than 0.5 MPa. By using compressed air or nitrogen as the second environmentally friendly gas, it has the advantage of being environmentally friendly. Since the pressure of the environmentally friendly gas filled inside the cylindrical housing is not less than 0.5 MPa, the insulation distance between the first isolating stationary contact and the grounding stationary contact can be reduced, as can the insulation distance between the first isolating stationary contact and the second isolating stationary contact. This makes the three-position disconnect switch smaller in size and lower in production and material costs.

[0029] The first environmentally friendly gas is compressed air or nitrogen; using compressed air or nitrogen as the first environmentally friendly gas has the advantage of being environmentally friendly.

[0030] A secondary instrument compartment 13 is provided on the top of the front side of the switch cabinet 1. Through the setting of the secondary instrument compartment, the controller in the secondary instrument compartment can realize the control and electrical operation of the switch cabinet, such as the control of the three-position operating mechanism and the vacuum circuit breaker operating mechanism. When the controller controls the three-position operating mechanism, it can switch the three-position disconnecting switch between grounding mode, isolation mode and conduction mode. When the controller controls the vacuum circuit breaker operating mechanism, the vacuum circuit breaker operating mechanism can realize the closing and opening control of the vacuum circuit breaker in the sealed pole type vacuum circuit breaker compartment 2.

[0031] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A miniaturized, environmentally friendly gas-insulated switchgear, comprising a switchgear cabinet (1), characterized in that: The inner rear side of the switch cabinet (1) is provided with an air box (11) and a cable compartment (12) arranged vertically. The air box (11) is filled with a first environmentally friendly gas. A sealed pole-type vacuum circuit breaker compartment (2) is fixed inside the air box (11). A box-type fully sealed three-position disconnect switch (3) is fixed on the outer top of the rear side of the switch cabinet (1). The box-type fully sealed three-position disconnect switch (3) is filled with a second environmentally friendly gas. The incoming terminal of the vacuum circuit breaker in the sealed pole-type vacuum circuit breaker compartment (2) is connected to the box-type... The output terminals of the fully sealed three-position disconnect switch (3) are electrically connected. The output terminals of the vacuum circuit breaker are connected to the side wall of the cable compartment (12) through the insulating sleeve (4). The cable in the cable compartment (12) passes through the insulating sleeve (4) and is electrically connected to the output terminals of the vacuum circuit breaker. The operating terminal of the vacuum circuit breaker is driven by the vacuum circuit breaker operating mechanism (5) located inside the front side of the switch cabinet (1). The box-type fully sealed three-position disconnect switch (3) is driven by the three-position operating mechanism (6) located inside the front side of the switch cabinet (1).

2. The miniaturized environmentally friendly gas-insulated switchgear according to claim 1, characterized in that: The box-type fully sealed three-position disconnect switch (3) includes a box-type housing (31), a transmission assembly (32), a grounding stationary contact (33), a first isolation stationary contact (34), a second isolation stationary contact (35), and a conductive element (36). The grounding stationary contact (33), the first isolation stationary contact (34), and the second isolation stationary contact (35) are sequentially and spaced apart on the side wall of the box-type housing (31) along the axial direction and are circumferentially sealed to the box-type housing (31). The conductive ends of the grounding stationary contact (33), the first isolation stationary contact (34), and the second isolation stationary contact (35) all extend into the interior of the box-type housing (31) and are coaxially arranged with the box-type housing (31). The conductive element (36) is axially movable and embedded in the first isolation stationary contact (35). In the conductive end of the isolating static contact base (34), the three-position operating mechanism (6) is fixed on the outer wall of the box-type housing (31), the transmission component (32) is rotatably and circumferentially sealed connected to one end of the box-type housing (31), the outer end of the transmission component (32) is connected to the driving end of the three-position operating mechanism (6), and the conductive element (36) is connected to the inner end of the transmission component (32); the three-position operating mechanism (6) is used to drive the conductive element (36) to move along the axial direction of the box-type housing (31) so that the box-type fully sealed three-position isolating switch (3) works in the grounding, isolation or conduction mode; the second environmentally friendly gas is filled into the box-type housing (31), and the input end of the vacuum circuit breaker is electrically connected to the output end of the second isolating static contact base (35).

3. The miniaturized environmentally friendly gas-insulated switchgear according to claim 2, characterized in that: The box-type fully sealed three-position disconnect switch (3) also includes a lead screw (37), one end of which is connected to the inner end of the transmission assembly (32). The conductive element (36) is a ring-shaped structure. One end of the conductive element (36) is embedded with an insulating connecting sleeve (38). The other end of the lead screw (37) passes through the insulating connecting sleeve (38) and is threadedly connected to the insulating connecting sleeve (38). When the motor in the three-position operating mechanism (6) drives the lead screw (37) to rotate via the transmission assembly (32), the lead screw (37) drives the conductive element (36) to move along the axial direction of the box-type housing (31) via the insulating connecting sleeve (38) so that the box-type fully sealed three-position disconnect switch (3) operates in grounding, isolation, or conduction mode.

4. The miniaturized environmentally friendly gas-insulated switchgear according to claim 3, characterized in that: A limiting groove (361) is axially provided on the outer wall of the conductive component (36). At least one limiting pin (39) is fixed on the side wall of the conductive end of the first isolation stationary contact seat (34). The inner end of the limiting pin (39) is inserted into the limiting groove (361) and can slide along the length direction of the limiting groove (361) when the conductive component (36) moves.

5. The miniaturized environmentally friendly gas-insulated switchgear according to claim 4, characterized in that: Two limiting pins (39) are fixed on the side wall of the conductive end of the first isolation stationary contact (34). The two limiting pins (39) are spaced apart along the axial direction of the conductive end of the first isolation stationary contact (34). The inner ends of the two limiting pins (39) are inserted into the limiting groove (361) and can slide along the length direction of the limiting groove (361) when the conductive member (36) moves.

6. The miniaturized environmentally friendly gas-insulated switchgear according to claim 3, characterized in that: The transmission assembly (32) includes a transmission shaft (321) and a rotary seal (322); the rotary seal (322) is fixed to one end of the cylindrical housing (31) and circumferentially sealed to the cylindrical housing (31); the transmission shaft (321) is rotatably inserted into the rotary seal (322) and circumferentially sealed to the rotary seal (322); the outer end of the transmission shaft (321) is connected to the drive end of the three-position operating mechanism (6); one end of the lead screw (37) is axially fixed to and connected to the inner end of the transmission shaft (321).

7. The miniaturized environmentally friendly gas-insulated switchgear according to any one of claims 2-6, characterized in that: The second environmentally friendly gas is compressed air or nitrogen, and the pressure of the environmentally friendly gas filled inside the cylindrical shell (31) is not less than 0.5 MPa.

8. The miniaturized environmentally friendly gas-insulated switchgear according to claim 1, characterized in that: The first environmentally friendly gas is compressed air or nitrogen.

9. The miniaturized environmentally friendly gas-insulated switchgear according to claim 1, characterized in that: A secondary instrument room (13) is provided on the top of the front side of the switch cabinet (1).

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