Environment-friendly gas-insulated switchgear and use method thereof

Abstract

The invention discloses an environment-friendly inflatable cabinet and a use method, and belongs to the technical field of switch equipment. The environment-friendly inflatable cabinet comprises an inflatable part and a non-inflatable part; the inflating part comprises an upper inflating compartment and a lower inflating compartment; a three-station isolating switch is mounted in the upper inflation compartment, a vacuum circuit breaker is mounted in the lower inflation compartment, and the upper inflation compartment is communicated with the lower inflation compartment through an insulator; the three-station isolating switch comprises a switching-on contact, a middle static contact, a moving contact and a grounding contact; the moving contact can be controlled to be in contact with or disconnected from the connection contact by adjusting the left movement of the moving contact, and can be controlled to be in contact with or disconnected from the grounding contact by adjusting the right movement of the moving contact. According to the environment-friendly inflatable cabinet, the problems of uneven electric field distribution and insufficient creepage distance under a low-pressure N2 / dry air insulating medium are solved by optimizing the layout of the inflatable compartments and improving the design of the three-station isolating switch structure and the operating mechanism, and the environment-friendly requirement is met at the same time.

Description

Technical Field

[0001] This invention relates to the field of switchgear technology, specifically to an environmentally friendly gas-insulated switchgear and its usage method. Background Technology

[0002] Currently, most 40.5kV gas-insulated switchgear on the market uses low-pressure SF6 gas as the insulating medium, paired with a knife-switch type three-position disconnector. Although SF6 gas has excellent insulation and arc-extinguishing properties, its greenhouse effect is significant (global warming potential GWP is approximately 23,500), which does not meet environmental protection requirements. Therefore, the industry is gradually exploring technical solutions to replace SF6 with low-pressure N2 / dry air.

[0003] However, the insulation strength of N2 / dry air is lower than that of SF6, requiring a larger creepage distance and a more optimized electric field distribution at the same voltage level. The structural design of traditional knife-switch type three-position disconnect switches (such as contact layout and insulation configuration) is not optimized for the characteristics of low-pressure media, which makes gas-filled switchgear using N2 / dry air as the insulating medium prone to phase-to-phase and phase-to-ground discharges or even breakdowns, failing to meet practical application requirements. Summary of the Invention

[0004] The first technical problem to be solved by the present invention is to provide an environmentally friendly gas-insulated switchgear. By optimizing the layout of the gas-insulated compartments, improving the structure of the three-position disconnect switch and the design of the operating mechanism, the problem of uneven electric field distribution and insufficient creepage distance under low-pressure N2 / dry air insulating medium is solved, while meeting environmental protection requirements.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An environmentally friendly inflatable cabinet includes an inflatable section located in the middle of the cabinet and non-inflatable sections located on the left and right sides of the inflatable section;

[0007] The inflation section includes an upper inflation compartment located above the cabinet and a lower inflation compartment located below the cabinet; a three-position disconnect switch is installed in the upper inflation compartment, and a vacuum circuit breaker is installed in the lower inflation compartment. The two are connected by an intermediate insulator to achieve electrical conduction and insulation isolation.

[0008] The non-pneumatic section includes a cable compartment located at the lower right of the cabinet, a mechanism compartment directly above the cable compartment, an instrument compartment directly above the mechanism compartment, and a pressure relief channel located at the upper left of the cabinet. The cable compartment is used to house cable connection terminals. The mechanism compartment is used to install a three-position operating mechanism and a circuit breaker spring operating mechanism. The circuit breaker spring operating mechanism is connected to the vacuum circuit breaker via an insulating pull rod, and the three-position operating mechanism is connected to a three-position switch via a magnetic fluid and a transmission screw. The instrument compartment is used to install measuring, protective, and monitoring instruments. The pressure relief channel is used to quickly release internal pressure under abnormal conditions to ensure the safety of equipment and personnel. The mechanism compartment houses the three-position operating mechanism and the circuit breaker spring operating mechanism.

[0009] Key improvements: The three-position disconnector includes a closing contact on the left, a middle stationary contact on the right side of the closing contact, a movable contact coaxially mounted on the middle stationary contact that can move left and right, and a grounding contact located on the right side of the middle stationary contact and fixedly connected to the aluminum plate of the cabinet. By adjusting the leftward movement of the movable contact, it can be controlled to make contact with or break off from the closing contact; by adjusting the rightward movement of the movable contact, it can be controlled to make contact with or break off from the grounding contact. The three-position disconnector also includes a supporting insulator fixedly connected to the bottom side of the closing contact and located at the bottom of the upper gas-filled compartment, and a middle insulator fixedly connected to the bottom side of the middle stationary contact and located at the bottom of the upper gas-filled compartment. The middle insulator connects the upper gas-filled compartment and the lower gas-filled compartment.

[0010] By adopting the above scheme, the three-position disconnecting switch in this environmentally friendly gas-filled switchgear has the connecting contact, intermediate stationary contact and grounding contact evenly distributed on the left and right, and the compartments are connected by the intermediate insulator, thus optimizing the electric field distribution inside and between the compartments; secondly, the design of switching by moving the moving contact left and right solves the problem of phase-to-phase / phase-to-ground discharge under low-pressure N2 / dry air because the moving contact has a small range of movement during switching, making the creepage distance more compliant with requirements.

[0011] As a preferred embodiment of an environmentally friendly gas-insulated switchgear, the three-position disconnect switch also includes an internal threaded hole coaxially opened at the center of the moving contact, a magnetic fluid fixedly connected to the aluminum plate, and a transmission screw coaxially installed in the middle stationary contact; the left end of the transmission screw is installed by threading into the internal threaded hole, and the transmission screw is driven to rotate by the magnetic fluid to realize the linear movement of the moving contact.

[0012] As a preferred embodiment of an environmentally friendly gas-insulated switchgear, at least one guide groove is provided on the outer side wall of the moving contact, and the guide groove is a through groove with openings on both the left and right sides; multiple axially arrayed guide mounting holes are provided through the side wall of the middle stationary contact, and guide plates extending into the guide groove are detachably installed in the guide mounting holes. The guide groove restricts the moving contact to move only axially, thus preventing the moving contact from deflecting.

[0013] As a preferred embodiment of an environmentally friendly gas-insulated switchgear, annular mounting grooves are provided on the inner sides of the grounding contact, intermediate stationary contact, and connecting contact. Annular spring contact fingers are fitted into the annular mounting grooves for limiting the movement of the contact. The moving contact is firmly in contact with the connecting contact, intermediate stationary contact, or grounding contact through the annular spring contact fingers. The compression of the spring contact fingers is less than 0.5mm after being compressed. The moving contact is in close contact with the corresponding contact through the spring contact fingers, ensuring low contact resistance under low-pressure media.

[0014] As a preferred embodiment of an environmentally friendly gas-insulated switchgear, the three-position disconnect switch also includes contact shields installed at the right end of the grounding contact, the left and right ends of the intermediate stationary contact, and the left end of the contact contact; at least one shield mounting hole is opened at the end of the grounding contact, the intermediate stationary contact, and the contact contact, and the contact shield is fixed in each shield mounting hole by installing hexagon countersunk screws. All hexagon countersunk screws are completely sunk into the contact shield, thereby suppressing tip discharge and further optimizing the electric field distribution.

[0015] As a preferred embodiment of an environmentally friendly gas-insulated switchgear, the connecting contact is equipped with a guide sleeve facing the moving contact. The right end of the guide sleeve is tapered, and the moving contact can be concentrically inserted into the guide sleeve when it moves to the left, further improving coaxiality and reducing the difficulty of contact between the two.

[0016] As a preferred embodiment of an environmentally friendly gas-insulated switchgear, the three-station operating mechanism includes an electric operating part consisting of a fixed frame, a drive motor mounted on the fixed frame, a gear one directly driven to rotate by the drive motor, a gear two meshing with the gear one, and a gear shaft concentrically connected to the gear two; the gear shaft has a hexagonal hole at its end, and the gear shaft is connected to a magnetic fluid limiting device through the hexagonal hole; the above is mainly achieved by the drive motor driving the gear shaft to rotate, which in turn drives the transmission screw to rotate, thereby realizing the linear movement of the moving contact.

[0017] As a preferred embodiment of an environmentally friendly gas-filled switchgear, the three-station operating mechanism also includes a manual operating part consisting of an operating hole on a fixed frame for inserting an operating handle, a gear three concentrically arranged with the operating hole for inserting the operating handle, and a gear four meshing with the gear three; the gear three meshes with the gear two through the gear four; the above is mainly achieved by driving the gear shaft to rotate through the operating handle, which in turn drives the transmission screw to rotate, thereby realizing the linear movement of the moving contact.

[0018] As a preferred embodiment of an environmentally friendly gas-insulated switchgear, the three-position operating mechanism also includes an indicator panel and an auxiliary switch coaxially connected to the indicator panel; the surface of the indicator panel is affixed with "closed", "open", and "grounded" status markings, and the auxiliary switch is connected to a gear transmission to output status signals to the monitoring system.

[0019] The second technical problem to be solved by the present invention is to provide a method for using an environmentally friendly gas-filled cabinet, which can be operated manually or electrically, making it more flexible in application.

[0020] A method for using an environmentally friendly gas-filled cabinet, comprising the following operating steps:

[0021] a: When the three-position switch is in the grounded position, the moving contact simultaneously contacts the intermediate stationary contact and the grounding contact. At this time, the gear two is driven to rotate counterclockwise several times by manual or electric operation. After synchronous transmission through the gear shaft, the magnetohydrodynamic fluid and the trigger screw are driven to rotate synchronously. Then, the moving contact moves from the grounding contact to the intermediate stationary contact under the transmission of the screw until the moving contact only contacts the intermediate stationary contact, which can realize the switch switching from grounding to isolation.

[0022] b: When the three-position switch is in the isolated position, the moving contact only contacts the middle stationary contact. At this time, the gear two is driven to rotate counterclockwise several times by manual or electric operation. After synchronous transmission through the gear shaft, the magnetohydrodynamic fluid and the trigger screw are driven to rotate synchronously. Then, the moving contact moves from the middle stationary contact to the contact contact under the transmission of the screw until the moving contact contacts both the middle stationary contact and the contact contact at the same time, which can realize the switch switching from isolated to connected.

[0023] c: When the three-position switch is in the ON position, the moving contact simultaneously contacts the intermediate stationary contact and the ON contact. At this time, the gear 2 is driven to rotate clockwise several times by manual or electric operation. After synchronous transmission through the gear shaft, the magnetohydrodynamic fluid and the trigger screw are driven to rotate synchronously. Then, the moving contact moves from the ON contact to the intermediate stationary contact under the transmission of the screw until the moving contact only contacts the intermediate stationary contact, which can realize the switch switching from ON to Isolation.

[0024] d: When the three-position switch is in the isolated position, the moving contact only contacts the middle stationary contact. At this time, the gear two is driven to rotate clockwise several times by manual or electric operation. After synchronous transmission through the gear shaft, the magnetohydrodynamic fluid and the trigger screw are driven to rotate synchronously. Then, the moving contact moves from the middle stationary contact to the grounding contact under the transmission of the thread until the moving contact simultaneously contacts the middle stationary contact and the grounding contact, which can realize the switch switching from isolation to grounding.

[0025] As a preferred implementation method for the use of an environmentally friendly gas-insulated switchgear, the electric operation steps are as follows: the drive motor directly rotates gear one clockwise or counterclockwise, which drives gear two to rotate synchronously; when gear two is driven to rotate, it drives the magnetohydrodynamic fluid and the transmission screw to rotate synchronously, completing the opening and closing operation of the moving contact, and realizing the switching of three different functions: busbar connection, isolation, and grounding;

[0026] The manual operation steps are as follows: Insert the operating handle into the operating hole and rotate the operating handle clockwise or counterclockwise. This will drive gear three to rotate synchronously. Through the meshing transmission of gear four, gear two can be rotated. When gear two is driven to rotate, it drives the magnetohydrodynamic fluid and the transmission screw to rotate synchronously, completing the opening and closing operation of the moving contact and realizing the switching of three different functions: bus connection, isolation, and grounding.

[0027] The beneficial effects of this invention are as follows:

[0028] 1. Adaptable to low-pressure media: The gas-filled section adopts an upper and lower split structure (the upper compartment houses a three-position switch, and the lower compartment houses a vacuum circuit breaker, with the compartments connected by an intermediate insulator). The three-position switch in the upper compartment adopts a left and right split structure (the connecting contact, the intermediate stationary contact, and the grounding contact are evenly distributed left and right), which optimizes the electric field distribution within and between the compartments. The three-position disconnecting switch uses a double limit of guide groove + guide plate, tight contact of spring contact fingers (compression ≤ 0.5mm), and a shielding cover to optimize the electric field, which makes the movement range of the moving contact smaller and solves the problem of phase-to-phase / phase-to-ground discharge under low-pressure N2 / dry air, making the creepage distance more compliant with requirements.

[0029] 2. Environmental friendliness: Replacing SF6 with low-pressure N2 / dry air results in near-zero greenhouse gas emissions, meeting the requirements of the "dual carbon" policy.

[0030] 3. High operational reliability: The moving contact of the three-position disconnect switch is constrained by a "screw-nut transmission (magnetic fluid drive) + guide structure", which ensures high movement accuracy and avoids deflection; the spring contact finger compression is small (≤0.5mm), which ensures good conductivity under low pressure and reduces contact wear, extending service life; the operating mechanism supports electric (automatic) and manual (emergency) dual modes to adapt to different scenario requirements; the indicating mechanism provides real-time status feedback for easy monitoring.

[0031] 4. Modular design: The non-pneumatic sections (cable compartment, mechanism compartment, instrument compartment) are rationally laid out with clear functional zoning, which facilitates installation, maintenance and expansion. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a front view structural diagram of an environmentally friendly gas-insulated cabinet.

[0034] Figure 2 for Figure 1 Main view of the three-position disconnector;

[0035] Figure 3 for Figure 2 Cross-sectional view of the moving contact;

[0036] Figure 4 for Figure 2 Longitudinal sectional view of the moving contact;

[0037] Figure 5 for Figure 2 Cross-sectional view of the middle stationary contact;

[0038] Figure 6 for Figure 2 Main view of the intermediate contact;

[0039] Figure 7 for Figure 2 Front view of the guide vane;

[0040] Figure 8 for Figure 2 Front view of the spring-loaded contact finger;

[0041] Figure 9 for Figure 1 Three-dimensional structure of the three-station operating mechanism Figure 1 ;

[0042] Figure 10 for Figure 1 Three-dimensional structure of the three-station operating mechanism Figure 2 ;

[0043] Figure 11 for Figure 1 Three-dimensional structure of the three-station operating mechanism Figure 3 ;

[0044] In the diagram, the markings are: 1-Three-position disconnector; 101-Magnetic fluid; 102-Aluminum plate; 103-Grounding contact; 104-Intermediate stationary contact; 105-Moving contact; 106-Connecting contact; 107-Supporting insulator; 108-Shielding cover; 109-Intermediate insulator; 110-Drive screw; 111-Internal threaded hole; 112-Guide groove; 113-Guide mounting hole; 114-Shielding cover mounting hole; 115-Guide sleeve; 116-Contact guide plate; 117- 1. Annular mounting slot; 2. Annular spring contact finger; 3. Circuit breaker switch; 4. Three-position operating mechanism; 5. Fixture; 6. Drive motor; 7. Gear 1; 8. Gear 2; 9. Gear shaft; 10. Hexagonal hole; 11. Operating hole; 12. Gear 3; 13. Gear 4; 14. Indicator panel; 15. Auxiliary switch; 16. Circuit breaker operating mechanism; 17. Mechanism compartment; 18. Cable compartment; 19. Pressure relief channel; 20. Instrument compartment. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] like Figures 1 to 2As shown, an environmentally friendly gas-insulated switchgear is provided, including an inflatable section located in the middle of the cabinet and non-inflatable sections located on the left and right sides of the inflatable section. The inflatable section includes an upper inflatable compartment located above the cabinet and a lower inflatable compartment located below the cabinet. A three-position disconnect switch 1 is installed in the upper inflatable compartment, and a vacuum circuit breaker is installed in the lower inflatable compartment. The two are connected by an intermediate insulator 109 to achieve electrical conduction and insulation isolation. The non-inflatable sections include a cable compartment 6 located at the lower right of the cabinet, a mechanism compartment 5 located directly above the cable compartment 6, an instrument compartment 8 located directly above the mechanism compartment 5, and a non-inflatable section located at the left side of the cabinet. The pressure relief channel 7 is located above; the cable compartment 6 is used to arrange cable connection terminals; the mechanism compartment 5 is used to install the three-position operating mechanism 3 and the circuit breaker spring operating mechanism. The circuit breaker spring operating mechanism is connected to the vacuum circuit breaker through an insulating pull rod. The three-position operating mechanism 3 is connected to the three-position switch through the magnetic fluid 101 and the transmission screw 110; the instrument compartment 8 is used to install measuring, protection and monitoring instruments; the pressure relief channel 7 is used to quickly release internal pressure under abnormal conditions to ensure the safety of equipment and personnel. The mechanism compartment 5 is equipped with the three-position operating mechanism 3 and the circuit breaker spring operating mechanism. Key improvements: The three-position disconnect switch 1 includes a connecting contact 106 on the left, a middle stationary contact 104 on the right side of the connecting contact 106, a movable contact 105 coaxially mounted on the middle stationary contact 104 that can move left and right, and a grounding contact 103 located on the right side of the middle stationary contact 104 and fixedly connected to the aluminum plate 102 of the cabinet. By adjusting the leftward movement of the movable contact 105, it can be controlled to contact or disconnect with the connecting contact 106, and by adjusting the rightward movement of the movable contact 105, it can be controlled to contact or disconnect with the grounding contact 103. The three-position disconnect switch 1 also includes a supporting insulator 107 fixedly connected to the bottom side of the connecting contact 106 and located at the bottom of the upper gas-filled compartment, and a middle insulator 109 fixedly connected to the bottom side of the middle stationary contact 104 and located at the bottom of the upper gas-filled compartment. The middle insulator 109 connects the upper gas-filled compartment and the lower gas-filled compartment. The three-position disconnector 1 in this environmentally friendly gas-insulated switchgear has the connecting contact 106, the intermediate stationary contact 104, and the grounding contact 103 evenly distributed on the left and right sides, and the compartments are connected by the intermediate insulator 109, which optimizes the electric field distribution within and between the compartments. After testing, the partial discharge is ≤5pC (the standard requirement is ≤10pC), and the electric field distribution is more uniform. Secondly, the design of switching by moving the moving contact 105 left and right solves the problem of phase-to-phase / phase-to-ground discharge under low-pressure N2 / dry air because the moving contact 105 has a small range of movement during switching. This makes the creepage distance more compliant with requirements. After testing, the power frequency withstand voltage (phase-to-ground / phase-to-phase) is 42kV / 48kV (the standard requirement is 42kV / 42kV), with no breakdown or flashover.

[0047] like Figure 2As shown, the three-position disconnect switch 1 also includes an internal threaded hole 111 coaxially opened at the center of the moving contact 105, a magnetic fluid 101 fixedly connected to the aluminum plate 102, and a transmission screw 110 coaxially installed in the intermediate stationary contact 104; the left end of the transmission screw 110 is installed in conjunction with the internal threaded hole 111 through a thread, and the transmission screw 110 is driven to rotate by the magnetic fluid 101 to realize the linear movement of the moving contact 105.

[0048] like Figures 4 to 5 , Figure 7 As shown, at least one guide groove 112 (two symmetrical grooves in the figure) is provided on the outer side wall of the moving contact 105. The guide groove 112 is a through groove with openings on both the left and right sides. Multiple axially arrayed guide mounting holes 113 are provided through the side wall of the middle stationary contact 104. A guide piece extending into the guide groove 112 is detachably installed in the guide mounting hole 113. The guide groove 112 restricts the moving contact 105 to move only axially, thus preventing the moving contact 105 from deflecting.

[0049] like Figure 5 , Figure 8 As shown, annular mounting grooves 117 are provided on the inner sides of the grounding contact 103, the intermediate stationary contact 104, and the connecting contact 106. Annular spring fingers 118 are fitted into the annular mounting grooves 117 for limiting. The moving contact 105 is firmly in contact with the connecting contact 106, the intermediate stationary contact 104, or the grounding contact 103 through the annular spring fingers 118. The compression of the spring fingers is less than 0.5 mm after being compressed. The moving contact 105 is in close contact with the corresponding contact through the spring fingers to ensure low contact resistance under low pressure medium.

[0050] like Figure 2 As shown, the three-position disconnect switch 1 also includes a contact shield 108 installed at the right end of the grounding contact 103, the left and right ends of the intermediate stationary contact 104, and the left end of the contact 106. At least one mounting hole for the shield 108 is opened at the end of the grounding contact 103, the intermediate stationary contact 104, and the contact 106 (two symmetrical holes are shown in the figure). The contact shield 108 is fixed in each mounting hole by installing hexagonal countersunk screws. All hexagonal countersunk screws are completely recessed into the contact shield 108 (the hexagonal countersunk screws are omitted in the figure), thereby suppressing tip discharge and further optimizing the electric field distribution.

[0051] like Figure 6 As shown, the connecting contact 106 is equipped with a guide sleeve 115 facing the moving contact 105. The right end of the guide sleeve 115 is tapered. When the moving contact 105 moves to the left, it can be concentrically inserted into the guide sleeve 115, further improving the coaxiality and reducing the difficulty of contact between the two.

[0052] like Figures 9 to 11As shown, the three-station operating mechanism 3 includes an electric operating part consisting of a fixed frame 301, a drive motor 302 mounted on the fixed frame 301, a gear 303 directly driven to rotate by the drive motor 302, a gear 304 meshing with the gear 303, and a gear shaft 305 concentrically connected to the gear 304. The gear shaft 305 has a hexagonal hole 306 at its end, and the gear shaft 305 is limitedly connected to the magnetic fluid 101 through the hexagonal hole 306. The drive motor 302 drives the gear shaft 305 to rotate, which in turn drives the transmission screw 110 to rotate, thereby realizing the linear movement of the moving contact 105.

[0053] Continue as Figures 9 to 11 As shown, the three-station operating mechanism 3 also includes a manual operating part consisting of an operating hole 307 opened on the fixed frame 301 for inserting an operating handle, a gear 308 concentrically arranged with the operating hole 307 for inserting an operating handle, and a gear 4 309 meshing with the gear 308; the gear 308 meshes with the gear 2 304 through the gear 4 309; the above is mainly achieved by driving the gear shaft 305 to rotate through the operating handle, which in turn drives the transmission screw 110 to rotate, thereby realizing the linear movement of the moving contact 105.

[0054] Continue as Figures 9 to 11 As shown, the three-position operating mechanism 3 also includes an indicator panel 310 and an auxiliary switch 311 coaxially connected to the indicator panel 310; the surface of the indicator panel 310 is affixed with "closed" (green), "open" (yellow), and "grounded" (red) status labels, and the auxiliary switch 311 is connected to the gear 304 for transmission, and is used to output status signals to the monitoring system and provide real-time feedback on the status of the three-position disconnector switch 1.

[0055] A method for using an environmentally friendly gas-filled cabinet, comprising the following operating steps:

[0056] a: When the three-position switch is in the grounded position, the moving contact 105 simultaneously contacts the intermediate stationary contact 104 and the grounding contact 103. At this time, the gear 2 304 is driven to rotate counterclockwise several times (about 66 times) by manual or electric operation. After synchronous transmission through the gear shaft 305, the magnetic fluid 101 and the trigger screw are driven to rotate synchronously. Then, the moving contact 105 moves from the grounding contact 103 to the intermediate stationary contact 104 under the transmission of the thread until the moving contact 105 only contacts the intermediate stationary contact 104, which can realize the switching from grounding to isolation.

[0057] b: When the three-position switch is in the isolated position, the moving contact 105 only contacts the intermediate stationary contact 104. At this time, the gear 2 304 is driven to rotate counterclockwise several times (about 66 times) by manual or electric operation. After synchronous transmission through the gear shaft 305, the magnetic fluid 101 and the trigger screw are driven to rotate synchronously. Then, the moving contact 105 moves from the intermediate stationary contact 104 to the closed contact 106 under the transmission of the thread until the moving contact 105 contacts both the intermediate stationary contact 104 and the closed contact 106 at the same time, so that the switch can be switched from isolated to closed.

[0058] c: When the three-position switch is in the ON position, the moving contact 105 simultaneously contacts the intermediate stationary contact 104 and the ON contact 106. At this time, the gear 304 is driven to rotate clockwise several times (approximately 66 times) by manual or electric operation. After synchronous transmission through the gear shaft 305, the magnetic fluid 101 and the trigger screw are driven to rotate synchronously. Subsequently, the moving contact 105 moves from the ON contact 106 to the intermediate stationary contact 104 under the transmission of the thread until the moving contact 105 only contacts the intermediate stationary contact 104, which realizes the switching from ON to Isolation.

[0059] d: When the three-position switch is in the isolated position, the moving contact 105 only contacts the intermediate stationary contact 104. At this time, the gear 304 is driven to rotate clockwise several times (about 66 times) by manual or electric operation. After synchronous transmission through the gear shaft 305, the magnetic fluid 101 and the trigger screw are driven to rotate synchronously. Then, the moving contact 105 moves from the intermediate stationary contact 104 to the grounding contact 103 under the transmission of the thread until the moving contact 105 simultaneously contacts the intermediate stationary contact 104 and the grounding contact 103, which realizes the switching from isolation to grounding.

[0060] The above electric operation steps are as follows: The drive motor 302 directly rotates the gear 303 clockwise or counterclockwise, which will drive the gear 304 to rotate synchronously; when the gear 304 is driven to rotate, it drives the magnetohydrodynamic fluid 101 and the transmission screw 110 to rotate synchronously, completing the opening and closing operation of the moving contact 105, realizing the switching of three different functions: bus connection, isolation and grounding.

[0061] The manual operation steps are as follows: Insert the operating handle into the operating hole 307 and rotate the operating handle clockwise or counterclockwise. This will drive gear three 308 to rotate synchronously. Through the meshing transmission of gear four 309, gear two 304 can be rotated. When gear two 304 is driven to rotate, it drives the magnetofluid 101 and the transmission screw 110 to rotate synchronously, completing the opening and closing operation of the moving contact 105, and realizing the switching of three different functions: bus connection, isolation, and grounding.

[0062] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An environmentally friendly gas-filled cabinet, comprising a gas-filled part in the middle of the cabinet body and non-gas-filled parts on both sides of the gas-filled part; the gas-filled part comprises an upper gas-filled compartment above the cabinet body and a lower gas-filled compartment below the cabinet body; a three-position disconnecting switch is installed in the upper gas-filled compartment, and a vacuum circuit breaker is installed in the lower gas-filled compartment, and the upper gas-filled compartment and the lower gas-filled compartment are communicated by insulators; characterized in that the three-position disconnecting switch comprises a closing contact on the left side, an intermediate static contact on the right side of the closing contact, a movable contact coaxially installed on the intermediate static contact and capable of moving left and right, and a grounding contact fixedly connected to the aluminum plate on the right side of the intermediate static contact; the movable contact can be controlled to be in contact or disconnected with the closing contact by adjusting the left movement of the movable contact, and the movable contact can be controlled to be in contact or disconnected with the grounding contact by adjusting the right movement of the movable contact; the three-position disconnecting switch further comprises a supporting insulator fixedly connected to the bottom side of the closing contact and located at the bottom of the upper gas-filled compartment, and an intermediate insulator fixedly connected to the bottom side of the intermediate static contact and located at the bottom of the upper gas-filled compartment; wherein the intermediate insulator connects the upper gas-filled compartment and the lower gas-filled compartment.

2. The environmentally friendly gas-insulated switchgear according to claim 1, characterized in that: the three-position disconnecting switch further comprises an internal screw hole coaxially opened at the center of the movable contact, a magnetic fluid fixedly connected to the aluminum plate, and a transmission screw rod coaxially installed in the intermediate static contact; the left end of the transmission screw rod is installed by thread cooperation with the internal screw hole.

3. The environmentally friendly gas-insulated switchgear according to claim 2, characterized in that: at least one guide groove is opened on the outer side wall of the movable contact, and the guide groove is a through groove with openings on both sides; a plurality of axially arrayed guide mounting holes are opened through the side wall of the intermediate static contact, and a guide piece inserted into the guide groove is detachably installed in the guide mounting hole.

4. The environmentally friendly gas-insulated switchgear according to claim 3, characterized in that: the inner side of the grounding contact, the intermediate static contact and the closing contact is provided with an annular mounting groove, and an annular spring contact finger is limitingly assembled in the annular mounting groove, and the movable contact is firmly abutted with the closing contact, the intermediate static contact or the grounding contact through the annular spring contact finger.

5. The environmentally friendly gas-insulated switchgear according to claim 4, characterized in that: the three-position disconnecting switch further comprises a contact shielding cover installed at the right end of the grounding contact, the left and right ends of the intermediate static contact and the left end of the closing contact; at least one shielding cover mounting hole is opened at the end of the grounding contact, the intermediate static contact and the closing contact, respectively, and the contact shielding cover is fixed in each shielding cover mounting hole by installing an internal hexagonal countersunk head screw, and all internal hexagonal countersunk head screws are completely sunk into the contact shielding cover.

6. The environmentally friendly gas-insulated switchgear according to claim 5, characterized in that: the closing contact is provided with a guide sleeve towards the movable contact, and the right end of the guide sleeve is conical, and the movable contact can be concentrically inserted into the guide sleeve when moving left.

7. The environmentally friendly gas-insulated switchgear according to claim 6, characterized in that: the three-position operating mechanism comprises an electric operating part composed of a fixed frame, a driving motor installed on the fixed frame, a gear one directly driven to rotate by the driving motor, a gear two in meshing transmission with the gear one, and a gear shaft concentrically connected with the gear two; a hexagonal hole is opened at the shaft end of the gear shaft, and the gear shaft is limitingly connected with the magnetic fluid through the hexagonal hole; the three-position operating mechanism further comprises a manual operating part composed of an operating hole opened on the fixed frame and capable of inserting an operating handle, a gear three concentrically arranged with the operating hole and capable of inserting the operating handle, and a gear four in meshing transmission with the gear two; the gear three is in meshing transmission with the gear two through the gear four. The three-position operating mechanism further comprises an indicating disc and an auxiliary switch coaxially connected to the indicating disc; the indicating disc is pasted with an indicating mark, and the auxiliary switch is in transmission connection with the second gear.

8. The environmentally friendly gas-insulated switchgear of claim 1, wherein: The non-inflatable part comprises a cable compartment located at the lower right of the cabinet, a mechanism compartment located directly above the cable compartment, an instrument compartment located directly above the mechanism compartment, and a pressure relief channel located at the upper left of the cabinet; The mechanism compartment is provided with a three-position operating mechanism and a circuit breaker spring operating mechanism; the circuit breaker spring operating mechanism is connected with the vacuum circuit breaker, and the three-position operating mechanism is connected with the three-position switch.

9. A method of using the environmentally friendly gas-insulated switchgear according to claim 7, characterized in that: The use method adopts the following operation steps: a: when the three-position switch is in the grounding position, the moving contact simultaneously contacts the intermediate static contact and the grounding contact, at this time, the second gear is driven to rotate counterclockwise by a number of turns in a manual operation or an electric operation mode, after synchronous transmission through the gear shaft, the magnetic fluid and the driving screw rod are synchronously rotated, then the moving contact moves from the grounding contact to the intermediate static contact under the transmission of the thread, until the moving contact only contacts the intermediate static contact, the switching of the switch from grounding to isolation can be realized; b: when the three-position switch is in the isolation position, the moving contact only contacts the intermediate static contact, at this time, the second gear is driven to rotate counterclockwise by a number of turns in a manual operation or an electric operation mode, after synchronous transmission through the gear shaft, the magnetic fluid and the driving screw rod are synchronously rotated, then the moving contact moves from the intermediate static contact to the on contact under the transmission of the thread, until the moving contact simultaneously contacts the intermediate static contact and the on contact, the switching of the switch from isolation to on can be realized; c: when the three-position switch is in the on position, the moving contact simultaneously contacts the intermediate static contact and the on contact, at this time, the second gear is driven to rotate clockwise by a number of turns in a manual operation or an electric operation mode, after synchronous transmission through the gear shaft, the magnetic fluid and the driving screw rod are synchronously rotated, then the moving contact moves from the on contact to the intermediate static contact under the transmission of the thread, until the moving contact only contacts the intermediate static contact, the switching of the switch from on to isolation can be realized; d: when the three-position switch is in the isolation position, the moving contact only contacts the intermediate static contact, at this time, the second gear is driven to rotate clockwise by a number of turns in a manual operation or an electric operation mode, after synchronous transmission through the gear shaft, the magnetic fluid and the driving screw rod are synchronously rotated, then the moving contact moves from the intermediate static contact to the grounding contact under the transmission of the thread, until the moving contact simultaneously contacts the intermediate static contact and the grounding contact, the switching of the switch from isolation to grounding can be realized.

10. The method of using the environmentally friendly gas-insulated switchgear of claim 9, wherein: The electric operation uses the following steps: the driving motor directly drives the first gear to rotate clockwise or counterclockwise, which drives the second gear to synchronously rotate; when the second gear is driven to rotate, the magnetic fluid and the driving screw rod are synchronously rotated, the opening and closing operation of the moving contact is completed, and the switching of the bus connection, isolation and grounding three different functions is realized. The manual operation uses the following steps: inserting the operation handle into the operation hole, rotating the operation handle clockwise or counterclockwise, driving the gear three to rotate synchronously, and through the meshing transmission of the gear four, the gear two can be rotated; when the gear two is driven to rotate, the magnetic fluid and the transmission screw rod are synchronously rotated, the opening and closing of the moving contact is completed, and the switching of the three different functions of the bus connection, isolation and grounding is realized.

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