Low-leakage-rate efficient sealing insulation medium-pressure gas cabinet and use method thereof

Abstract

The invention discloses a low-leakage-rate efficient sealing insulation medium-pressure gas cabinet and a using method thereof.The low-leakage-rate efficient sealing insulation medium-pressure gas cabinet comprises a double-layer vacuum cabinet body assembly, a cabinet door is hinged to the double-layer vacuum cabinet body assembly, and a labyrinth sealing assembly is arranged at the joint of the double-layer vacuum cabinet body assembly and the cabinet door; the inlet and outlet wire insulation sealing assembly is arranged on the rear side of the double-layer vacuum cabinet body assembly, the gas circulation purification assembly is arranged in the double-layer vacuum cabinet body assembly, the monitoring control assembly is arranged on the double-layer vacuum cabinet body assembly and a cabinet door, and the monitoring control assembly is electrically connected with the gas circulation purification assembly. According to the invention, a double-sealing structure of the double-layer vacuum cabinet body assembly and the labyrinth sealing assembly is adopted, and the vacuum cavity and the labyrinth sealing structure are formed to be matched with the fluororubber sealing ring with the compression amount of 20-25%, so that the gas leakage path is greatly prolonged, and the gas leakage rate is effectively reduced.

Description

Technical Field

[0001] This invention belongs to the technical field of medium-voltage gas switchgear, specifically relating to a low-leakage, high-efficiency sealed and insulated medium-voltage gas switchgear and its usage method. Background Technology

[0002] Medium-voltage gas switchgear is a core piece of equipment in power distribution networks. It typically uses environmentally friendly gases such as dry air and nitrogen as insulation and arc-quenching media, and is widely used in industrial plants, high-rise buildings, substations and other scenarios.

[0003] Existing medium-pressure gas switchgear generally suffers from technical defects such as high leakage rate and unstable insulation performance in its sealing structure. The joints of the switchgear and the inlet and outlet ports are mostly sealed with a single rubber sealing ring. After long-term operation, the sealing ring is prone to aging and deformation, leading to gas leakage. Meanwhile, external moisture can easily penetrate the cabinet, reducing insulation strength and causing faults such as creepage and flashover. Furthermore, existing gas cabinets lack real-time monitoring and control methods, making it impossible to keep track of the gas status inside the cabinet in real time, resulting in high operation and maintenance costs. Therefore, we propose a high-efficiency sealed and insulated medium-voltage gas cabinet with low leakage rate and its usage method. Summary of the Invention

[0004] The purpose of this invention is to provide a high-efficiency sealed and insulated medium-voltage gas cabinet with low leakage rate and its usage method, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a high-efficiency sealed and insulated medium-voltage gas cabinet with low leakage rate, comprising: A double-layer vacuum cabinet assembly, wherein a cabinet door is hinged to the double-layer vacuum cabinet assembly; A labyrinth sealing assembly is disposed between the connection between the double-layer vacuum cabinet assembly and the cabinet door, for achieving a double seal between the double-layer vacuum cabinet assembly and the cabinet door; The inlet and outlet line insulation sealing assembly is located on the rear side of the double-layer vacuum cabinet assembly and is used to achieve inlet and outlet line sealing and insulation protection for the medium-pressure gas cabinet. A gas circulation and purification component is installed inside the double-layer vacuum cabinet assembly to achieve gas filtration, drying and circulation within the medium-pressure gas cabinet; A monitoring and control component is installed on the double-layer vacuum cabinet assembly and the cabinet door, and is used to monitor the gas pressure, temperature and humidity and gas leakage status inside the medium-pressure gas cabinet in real time. The monitoring and control component is electrically connected to the gas circulation and purification component, and controls the start-up, shutdown, and operation mode of the gas circulation and purification component based on the monitoring data.

[0006] Preferably, the double-layer vacuum cabinet assembly includes an outer cabinet and an inner cabinet; The inner cabinet is located inside the outer cabinet. The joint between the outer cabinet and the inner cabinet is sealed with copper-based brazing, and a vacuum cavity is formed between them. The vacuum chamber is evacuated to a vacuum level of ≤1Pa, and its evacuation port is sealed by welding with a metal bellows sealing valve.

[0007] Preferably, the labyrinth sealing assembly includes a labyrinth groove, a central convex strip, a labyrinth convex frame, a central groove, and a fluororubber sealing ring; The double-layer vacuum cabinet assembly has a labyrinth groove on its open side, and a central protrusion is provided in the center of the labyrinth groove. A labyrinth frame is provided on the cabinet door at the position corresponding to the labyrinth groove, and a central groove is provided on the labyrinth frame at the position corresponding to the central protrusion. The labyrinth groove, the central protrusion, the labyrinth frame, and the central groove cooperate to form a labyrinth sealing structure. The fluororubber sealing rings are embedded on both the inner and outer sides of the central protrusion within the labyrinth groove, and the compression of the fluororubber sealing rings is controlled to be 20%-25%.

[0008] Preferably, the space between the double-layer vacuum cabinet assembly and the cabinet door is filled with a gas medium, which is a mixture of dry air and nitrogen in a volume ratio of 7:3, and the filling pressure is 0.3-0.5 MPa.

[0009] Preferably, the inlet / outlet insulation sealing assembly includes an inlet / outlet port, a sealing flange, a sealing tube, and an insulating thermoplastic sleeve; The inlet / outlet is located on the rear side of the double-layer vacuum cabinet assembly, and a sealing flange is provided thereon. The weld between the inlet / outlet and the double-layer vacuum cabinet assembly is coated with anti-corrosion sealant. The sealing tube is inserted into the inlet / outlet, and its outer end is connected to another sealing flange. The two sealing flanges are locked and fixedly connected by bolts and nuts. The insulating thermoplastic sleeve is installed on the outermost sealing flange and communicates with the sealing insert for thermoplastic sealing of the inlet and outlet lines.

[0010] Preferably, a polymer sealant layer is coated between the sealing tube and the inlet / outlet, and a sealing gasket is provided between the two sealing flanges.

[0011] Preferably, the gas circulation and purification assembly includes a circulating fan, a dryer filter, a dust filter, and a gas return pipe; The circulating fan, the drying filter, and the dust filter are located at the bottom inner side of the inner cabinet, and the drying filter and the dust filter are connected in series at the air outlet of the circulating fan through a connecting pipe, for adsorbing moisture in the medium-pressure gas cabinet and impurity particles in the filtered gas. The gas return pipe is connected to the output end of the dust filter and extends through the vacuum chamber to the top of the inner cabinet, thereby achieving gas circulation and purification. The gas return pipe and the inner cabinet both use a welded sealing structure at their penetration points.

[0012] Preferably, the monitoring and control components include a differential pressure sensor, a humidity sensor, a temperature sensor, a gas leak detector, an alarm, and a controller; The differential pressure sensor is disposed between the vacuum chamber and the inner cabinet to monitor changes in gas pressure within the inner cabinet. Both the humidity sensor and the temperature sensor are located on the top inner side of the inner cabinet and are used to monitor the temperature and humidity inside the inner cabinet. The gas leak detector is located on the outside of the outer cabinet, and the detection probe of the gas leak detector extends to the sealing connection between the double-layer vacuum cabinet assembly and the cabinet door, for real-time monitoring of gas leakage. The differential pressure sensor, humidity sensor, temperature sensor, and gas leak detector are all electrically connected to the controller, which receives monitoring signals in real time. The alarm is installed at the top of the outer cabinet and is electrically connected to the controller. When abnormal pressure, excessive leakage, or excessive temperature and humidity are detected, the controller controls the alarm to emit an audible and visual alarm.

[0013] Preferably, the controller is also connected to the circulating fan. When the humidity sensor detects that the humidity inside the inner cabinet is >8% RH, the controller controls the circulating fan to start and run continuously. When the humidity is ≤5% RH, the controller controls the circulating fan to switch to intermittent operation mode.

[0014] A method for using a low-leakage, high-efficiency, sealed, insulated medium-voltage gas switchgear, based on which the low-leakage, high-efficiency, sealed, insulated medium-voltage gas switchgear includes the following steps: S1. Cabinet sealing assembly: The joint between the outer and inner cabinets of the double-layer vacuum cabinet assembly is sealed with copper-based brazing. After assembly, the vacuum chamber between the two is evacuated to a vacuum level ≤1Pa, and the extraction port is sealed by welding with a metal bellows sealing valve. A labyrinth sealing assembly is installed at the connection between the double-layer vacuum cabinet assembly and the cabinet door to ensure precise fit between the labyrinth convex frame and the labyrinth groove, and the compression of the fluororubber sealing ring is controlled at 20%-25%. S2. Inlet and outlet line sealing assembly: Insert the sealing tube into the inlet and outlet ports, apply a polymer sealant layer to the gap between the sealing tube and the inlet and outlet ports, lock and fix it with two sealing flanges with sealing gaskets, install an insulating thermoplastic sleeve on the outermost sealing flange and complete the thermoplastic sealing of the inlet and outlet ports. S3, Insulating gas filling: Fill the inner cabinet of the double-layer vacuum cabinet assembly with a mixture of dry air and nitrogen in a volume ratio of 7:3. Stop filling after the filling pressure reaches 0.3-0.5MPa. S4. Circulation purification and monitoring operation: The monitoring and control components are activated to monitor the pressure, temperature, humidity, and leakage at the sealing joints of the inner cabinet in real time. When the humidity sensor detects humidity > 8% RH, the controller controls the circulating fan of the gas circulation and purification components to start and run continuously. When the humidity is ≤ 5% RH, it switches to intermittent operation mode. S5. Exception Handling: When the pressure inside the inner cabinet is monitored to be <0.3MPa and the leakage is >1×10⁻ 7 When the humidity is greater than 8%RH or the m³ / (s・Pa) is high, the controller will activate the alarm with sound and light, stop the machine to check the sealing structure and replenish the insulating gas.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. Low leakage rate: It adopts a double sealing structure of double-layer vacuum cabinet assembly and labyrinth seal assembly. The splicing seam of the outer and inner cabinets is sealed with copper-based brazing. The vacuum degree of the vacuum chamber is ≤1Pa. The labyrinth seal structure is combined with fluororubber sealing rings with a compression of 20%-25%, which greatly extends the gas leakage path and effectively reduces the gas leakage rate. 2. High-efficiency insulation: The inner cabinet is filled with a mixture of dry air and nitrogen in a volume ratio of 7:3. Combined with the continuous purification of the gas circulation and purification components, the gas is kept dry and clean. The insulating thermoplastic sleeves and multiple sealing structures of the inlet and outlet insulation sealing components improve the insulation performance of the inlet and outlet parts and prevent creepage and flashover faults. 3. Intelligent operation and maintenance: The monitoring and control components monitor the pressure, temperature, humidity and leakage in the cabinet in real time, and automatically alarm in case of abnormality; the controller automatically controls the operation mode of the circulating fan according to the humidity data, reducing the workload of manual operation and maintenance and energy consumption; 4. Environmentally friendly and economical: It uses a mixture of dry air and nitrogen as the insulating medium, eliminating the risk of greenhouse effect; the low leakage rate design reduces the amount of gas replenishment and lowers operation and maintenance costs. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall three-dimensional structure of the present invention; Figure 2 This is a schematic diagram of the overall three-dimensional structure of the present invention; Figure 3 This is a schematic diagram of the overall three-dimensional structure of the present invention; Figure 4 This is a schematic diagram of the main structure of the present invention; Figure 5 This is a side sectional view of the present invention. Figure 6 This is a schematic diagram of the front cross-sectional structure of the present invention.

[0017] In the diagram: 1. Double-layer vacuum cabinet assembly; 101. Outer cabinet; 102. Inner cabinet; 103. Vacuum chamber; 2. Cabinet door; 3. Labyrinth sealing assembly; 301. Labyrinth groove; 302. Central convex strip; 303. Labyrinth convex frame; 304. Central groove; 305. Fluororubber sealing ring; 4. Inlet / outlet insulation sealing assembly; 401. Inlet / outlet port; 402. Sealing flange; 403. Sealing tube; 404. Insulating thermoplastic sleeve; 5. Gas circulation and purification assembly; 501. Circulating fan; 502. Dryer filter; 503. Dust filter; 504. Gas return pipe; 6. Monitoring and control assembly; 601. Micro differential pressure sensor; 602. Humidity sensor; 603. Temperature sensor; 604. Gas leak detector; 605. Alarm; 606. Controller. Detailed Implementation

[0018] 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.

[0019] Please see Figures 1-6 The present invention provides a low-leakage, high-efficiency, sealed and insulated medium-voltage gas cabinet, comprising a double-layer vacuum cabinet assembly 1, a cabinet door 2, a labyrinth seal assembly 3, an inlet / outlet wire insulation seal assembly 4, a gas circulation and purification assembly 5, and a monitoring and control assembly 6. A cabinet door 2 is hinged to the double-layer vacuum cabinet assembly 1; The labyrinth sealing component 3 is disposed between the connection between the double-layer vacuum cabinet component 1 and the cabinet door 2, and is used to achieve a double seal between the double-layer vacuum cabinet component 1 and the cabinet door 2; The inlet and outlet insulation sealing assembly 4 is located on the rear side of the double-layer vacuum cabinet assembly 1, and is used to achieve inlet and outlet sealing and insulation protection for the medium-pressure gas cabinet. The gas circulation and purification component 5 is installed inside the double-layer vacuum cabinet component 1 to achieve gas filtration, drying and circulation in the medium-pressure gas cabinet; The monitoring and control component 6 is installed on the double-layer vacuum cabinet component 1 and the cabinet door 2, and is used to monitor the gas pressure, temperature and humidity and gas leakage status in the medium-pressure gas cabinet in real time. The monitoring and control component 6 is electrically connected to the gas circulation and purification component 5, and controls the start-up, shutdown and operation mode of the gas circulation and purification component 5 according to the monitoring data. The double-layer vacuum cabinet assembly 1 includes an outer cabinet 101 and an inner cabinet 102. The inner cabinet 102 is located inside the outer cabinet 101. The joint between the outer cabinet 101 and the inner cabinet 102 is sealed with copper-based brazing to avoid defects such as pores and slag inclusions at the joint, thereby improving the basic sealing performance. A vacuum chamber 103 is formed between the outer cabinet 101 and the inner cabinet 102. The vacuum chamber 103 is evacuated to a vacuum level of ≤1Pa. Its air extraction port is sealed with a metal bellows sealing valve. The vacuum chamber 103 can effectively prevent outside air and moisture from entering the inner cabinet 102, while reducing heat transfer within the cabinet and preventing excessive temperature fluctuations inside the inner cabinet 102. The labyrinth sealing assembly 3 includes a labyrinth groove 301, a central convex strip 302, a labyrinth convex frame 303, a central groove 304, and a fluororubber sealing ring 305. The labyrinth groove 301 is provided on the opening side of the double-layer vacuum cabinet assembly 1. A central convex strip 302 is provided in the center of the labyrinth groove 301. A labyrinth convex frame 303 is provided on the cabinet door 2 at the position corresponding to the labyrinth groove 301. A central groove 304 is provided on the labyrinth convex frame 303 at the position corresponding to the central convex strip 302. The labyrinth groove 301, the central convex strip 302, the labyrinth convex frame 303, and the central groove 304 work together to form a labyrinth sealing structure, which extends the gas leakage path and initially blocks gas leakage. Fluororubber sealing rings 305 are embedded on both the inner and outer sides of the central protrusion 302 in the labyrinth groove 301. The compression of the fluororubber sealing rings 305 is controlled at 20%-25%. This compression ensures that the sealing ring fits tightly with the sealing surface and prevents the sealing ring from aging faster due to excessive compression, thus achieving a double sealing effect. The space between the double-layer vacuum cabinet assembly 1 and the cabinet door 2 is filled with a gaseous medium, which is a mixture of dry air and nitrogen in a volume ratio of 7:3, with a filling pressure of 0.3-0.5 MPa. This mixed gas has excellent insulation and arc-extinguishing properties and does not produce a greenhouse effect, making it more environmentally friendly than traditional sulfur hexafluoride gas. Controlling the filling pressure within the range of 0.3-0.5 MPa ensures the insulation strength of the gaseous medium while preventing the cabinet from being subjected to excessive pressure. The inlet / outlet insulation and sealing assembly 4 includes an inlet / outlet port 401, a sealing flange 402, a sealing tube 403, and an insulating thermoplastic sleeve 404. The inlet / outlet port 401 is located on the rear side of the double-layer vacuum cabinet assembly 1, and a sealing flange 402 is provided on it. The weld between the inlet / outlet port 401 and the double-layer vacuum cabinet assembly 1 is coated with anti-corrosion sealing paint to prevent corrosion at the weld from causing sealing failure. The sealing tube 403 is inserted into the inlet / outlet port 401, and its outer end is connected to another sealing flange 402. The two sealing flanges 402 are locked and fixed together by bolts and nuts. A polymer sealing layer is coated between the sealing tube 403 and the inlet / outlet port 401, and a sealing gasket is provided between the two sealing flanges 402. The multiple sealing structure can effectively prevent gas from leaking from the inlet / outlet port 401. Insulating thermoplastic sleeve 404 is installed on the outermost sealing flange 402 and connected to sealing tube 403. It is used for thermoplastic sealing of the inlet and outlet lines to improve the insulation performance of the inlet and outlet lines and prevent leakage. The gas circulation and purification assembly 5 includes a circulating fan 501, a dryer filter 502, a dust filter 503, and a gas return pipe 504. The circulating fan 501, the dryer filter 502, and the dust filter 503 are located at the bottom inner side of the inner cabinet 102, and the dryer filter 502 and the dust filter 503 are connected in series at the air outlet of the circulating fan 501 through a connecting pipe, which is used to adsorb moisture in the medium-pressure gas cabinet and filter impurity particles in the gas. The gas return pipe 504 is connected to the output end of the dust filter 503 and extends through the vacuum chamber 103 to the top of the inner cabinet 102 to achieve gas circulation and purification; the penetration between the gas return pipe 504 and the inner cabinet 102 is sealed by welding to prevent gas from leaking from the penetration. During operation, the circulating fan 501 extracts the gas from the bottom of the inner cabinet 102. The gas passes through the dust filter 503 and the dryer filter 502 in sequence. The dust filter 503 filters out impurity particles in the gas, and the dryer filter 502 adsorbs moisture in the gas. The purified gas is transported to the top of the inner cabinet 102 through the gas return pipe 504 to realize the internal circulation of gas, maintain the dryness and cleanliness of the gas inside the inner cabinet 102, and ensure stable insulation performance. The monitoring and control component 6 includes a differential pressure sensor 601, a humidity sensor 602, a temperature sensor 603, a gas leak detector 604, an alarm 605, and a controller 606; A differential pressure sensor 601 is disposed between the vacuum chamber 103 and the inner cabinet 102 to monitor changes in gas pressure inside the inner cabinet 102. Humidity sensor 602 and temperature sensor 603 are both installed on the top inner side of inner cabinet 102 to monitor the temperature and humidity inside inner cabinet 102. The gas leak detector 604 is located on the outside of the outer cabinet 101, and the detection probe of the gas leak detector 604 extends to the sealing connection between the double-layer vacuum cabinet assembly 1 and the cabinet door 2, for real-time monitoring of gas leakage. The differential pressure sensor 601, humidity sensor 602, temperature sensor 603 and gas leak detector 604 are all electrically connected to the controller 606, which receives monitoring signals in real time. Alarm 605 is installed at the top of the outer cabinet 101. Alarm 605 is electrically connected to controller 606. When abnormal pressure, excessive leakage, or excessive temperature and humidity are detected, controller 606 controls alarm 605 to issue an audible and visual alarm. The controller 606 is also connected to the circulating fan 501. When the humidity sensor 602 detects that the humidity inside the inner cabinet 102 is greater than 8% RH, the controller 606 controls the circulating fan 501 to start and run continuously. When the humidity is less than or equal to 5% RH, the controller 606 controls the circulating fan 501 to switch to intermittent operation mode to reduce energy consumption while ensuring the gas is dry.

[0020] The method of using the low-leakage, high-efficiency sealed and insulated medium-voltage gas switch provided by this invention includes the following steps: S1. Cabinet sealing assembly: The joint between the outer cabinet 101 and the inner cabinet 102 of the double-layer vacuum cabinet assembly 1 is sealed with copper-based brazing. After assembly, the vacuum chamber 103 between the two is evacuated to a vacuum degree ≤1Pa, and the exhaust port is sealed by welding with a metal bellows sealing valve. A labyrinth sealing assembly 3 is installed at the connection between the double-layer vacuum cabinet assembly 1 and the cabinet door 2 to ensure precise fit between the labyrinth convex frame 303 and the labyrinth groove 301, and the compression of the fluororubber sealing ring 305 is controlled at 20%-25%. S2. Inlet and outlet line sealing assembly: Insert the sealing tube 403 into the inlet / outlet port 401, apply a polymer sealant layer to the gap between the sealing tube 403 and the inlet / outlet port 401, lock and fix it by two sealing flanges 402 with sealing gaskets, install the insulating thermoplastic sleeve 404 on the outermost sealing flange 402 and complete the thermoplastic sealing of the inlet / outlet. S3, Insulating gas filling: A mixture of dry air and nitrogen in a volume ratio of 7:3 is introduced into the inner cabinet 102 of the double-layer vacuum cabinet assembly 1. The inflation is stopped after the inflation pressure reaches 0.3-0.5MPa. S4. Circulation purification and monitoring operation: The monitoring and control component 6 is activated to monitor the pressure, temperature, humidity and leakage at the sealing connection in the inner cabinet 102 in real time. When the humidity sensor 602 detects humidity > 8% RH, the controller 606 controls the circulating fan 501 of the gas circulation and purification component 5 to start and run continuously. When the humidity is ≤ 5% RH, it switches to intermittent operation mode. S5. Exception Handling: When the pressure inside the inner cabinet 102 is monitored to be <0.3MPa and the leakage is >1×10⁻ 7 When the humidity is greater than 8%RH or the m³ / s・Pa, the controller 606 controls the alarm 605 to issue an audible and visual alarm, stop the machine to check the sealing structure and replenish the insulating gas.

[0021] The present invention has the following beneficial effects: 1. Low leakage rate: The double sealing structure of double-layer vacuum cabinet assembly 1 and labyrinth seal assembly 3 is adopted. The splicing seam of outer cabinet 101 and inner cabinet 102 is sealed with copper-based brazing. The vacuum degree of vacuum chamber 103 is ≤1Pa. The labyrinth seal structure is combined with fluororubber sealing ring 305 with a compression of 20%-25%, which greatly extends the gas leakage path and effectively reduces the gas leakage rate. 2. High-efficiency insulation: The inner cabinet 102 is filled with a mixture of dry air and nitrogen in a volume ratio of 7:3. Combined with the continuous purification of the gas circulation and purification component 5, the gas is kept dry and clean. The insulating thermoplastic sleeve 404 and the multiple sealing structure of the inlet and outlet insulation sealing component 4 improve the insulation performance of the inlet and outlet parts and avoid creepage and flashover faults. 3. Intelligent operation and maintenance: The monitoring and control component 6 monitors the pressure, temperature, humidity and leakage in the cabinet in real time, and automatically alarms in case of abnormality; the controller 606 automatically controls the operation mode of the circulating fan 501 according to the humidity data, reducing the workload of manual operation and maintenance and energy consumption. 4. Environmentally friendly and economical: It uses a mixture of dry air and nitrogen as the insulating medium, eliminating the risk of greenhouse effect; the low leakage rate design reduces the amount of gas replenishment and lowers operation and maintenance costs.

[0022] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-efficiency sealed and insulated medium-voltage gas switch with low leakage rate, characterized in that, include: A double-layer vacuum cabinet assembly (1) is provided with a cabinet door (2) hinged to the double-layer vacuum cabinet assembly (1). A labyrinth sealing assembly (3) is disposed between the connection between the double-layer vacuum cabinet assembly (1) and the cabinet door (2) to achieve a double seal between the double-layer vacuum cabinet assembly (1) and the cabinet door (2); Inlet and outlet line insulation sealing assembly (4), the inlet and outlet line insulation sealing assembly (4) is disposed on the rear side of the double-layer vacuum cabinet assembly (1) and is used to realize the inlet and outlet line sealing and insulation protection of the medium-pressure gas cabinet; Gas circulation and purification component (5), which is installed inside the double-layer vacuum cabinet component (1) to realize gas filtration, drying and circulation in the medium-pressure gas cabinet; The monitoring and control component (6) is installed on the double-layer vacuum cabinet assembly (1) and the cabinet door (2) for real-time monitoring of gas pressure, temperature and humidity and gas leakage status in the medium-pressure gas cabinet; The monitoring and control component (6) and the gas circulation and purification component (5) are electrically connected, and the start-up, shutdown and operation mode of the gas circulation and purification component (5) are controlled according to the monitoring data.

2. The low-leakage, high-efficiency sealed and insulated medium-voltage gas cabinet according to claim 1, characterized in that: The double-layer vacuum cabinet assembly (1) includes an outer cabinet (101) and an inner cabinet (102). The inner cabinet (102) is located inside the outer cabinet (101). The joint between the outer cabinet (101) and the inner cabinet (102) is sealed with copper-based brazing, and a vacuum cavity (103) is formed between them. The vacuum chamber (103) is evacuated to a vacuum level of ≤1Pa, and its evacuation port is sealed by welding with a metal bellows sealing valve.

3. The low-leakage, high-efficiency sealed and insulated medium-voltage gas cabinet according to claim 1, characterized in that: The labyrinth sealing assembly (3) includes a labyrinth groove (301), a central convex strip (302), a labyrinth convex frame (303), a central groove (304), and a fluororubber sealing ring (305). The double-layer vacuum cabinet assembly (1) has a labyrinth groove (301) on its open side. A central protrusion (302) is provided in the center of the labyrinth groove (301). A labyrinth frame (303) is provided on the cabinet door (2) at the position corresponding to the labyrinth groove (301). A central groove (304) is provided on the labyrinth frame (303) at the position corresponding to the central protrusion (302). The labyrinth groove (301), the central protrusion (302), the labyrinth frame (303), and the central groove (304) cooperate to form a labyrinth sealing structure. The labyrinth groove (301) is provided with fluororubber sealing rings (305) on both the inner and outer sides corresponding to the central protrusion (302), and the compression of the fluororubber sealing rings (305) is controlled to be 20%-25%.

4. The low-leakage, high-efficiency sealed and insulated medium-pressure gas cabinet according to claim 1, characterized in that: The space between the double-layer vacuum cabinet assembly (1) and the cabinet door (2) is filled with a gas medium, which is a mixture of dry air and nitrogen in a volume ratio of 7:3, and the filling pressure is 0.3-0.5 MPa.

5. The low-leakage, high-efficiency sealed and insulated medium-voltage gas cabinet according to claim 1, characterized in that: The inlet / outlet insulation and sealing assembly (4) includes an inlet / outlet port (401), a sealing flange (402), a sealing tube (403), and an insulating thermoplastic sleeve (404). The inlet / outlet port (401) is located on the rear side of the double-layer vacuum cabinet assembly (1), and a sealing flange (402) is provided thereon. The weld between the inlet / outlet port (401) and the double-layer vacuum cabinet assembly (1) is coated with anti-corrosion sealing paint. The sealing tube (403) is inserted into the inlet / outlet port (401), and its outer end is connected to another sealing flange (402). The two sealing flanges (402) are locked and fixedly connected by bolts and nuts. The insulating thermoplastic sleeve (404) is disposed on the outermost sealing flange (402) and communicates with the sealing tube (403) for thermoplastic sealing of the inlet and outlet lines.

6. The low-leakage, high-efficiency sealed and insulated medium-voltage gas cabinet according to claim 5, characterized in that: A polymer sealant layer is coated between the sealing tube (403) and the inlet / outlet port (401), and a sealing gasket is provided between the two sealing flanges (402).

7. The low-leakage, high-efficiency sealed and insulated medium-voltage gas cabinet according to claim 2, characterized in that: The gas circulation and purification component (5) includes a circulating fan (501), a dryer filter (502), a dust filter (503), and a gas return pipe (504). The circulating fan (501), the drying filter (502) and the dust filter (503) are located at the bottom inside of the inner cabinet (102), and the drying filter (502) and the dust filter (503) are connected in series at the air outlet of the circulating fan (502) through a connecting pipe, for adsorbing moisture in the medium-pressure gas cabinet and filtering impurity particles in the gas. The gas return pipe (504) is connected to the output end of the dust filter (503) and extends through the vacuum chamber (103) to the top of the inner cabinet (102) to achieve gas circulation and purification. The gas return pipe (504) and the inner cabinet (102) are connected by a welded sealing structure.

8. The low-leakage, high-efficiency sealed and insulated medium-voltage gas cabinet according to claim 7, characterized in that: The monitoring and control component (6) includes a differential pressure sensor (601), a humidity sensor (602), a temperature sensor (603), a gas leak detector (604), an alarm (605), and a controller (606). The micro differential pressure sensor (601) is disposed between the vacuum chamber (103) and the inner cabinet (102) to monitor the gas pressure change inside the inner cabinet (102); The humidity sensor (602) and the temperature sensor (603) are both located on the top inner side of the inner cabinet (102) and are used to monitor the temperature and humidity inside the inner cabinet (102). The gas leak detector (604) is located on the outside of the outer cabinet (101), and the detection probe of the gas leak detector (604) extends to the sealing connection between the double-layer vacuum cabinet assembly (1) and the cabinet door (2) for real-time monitoring of gas leakage. The differential pressure sensor (601), the humidity sensor (602), the temperature sensor (603), and the gas leak detector (604) are all electrically connected to the controller (606), which receives monitoring signals in real time. The alarm (605) is located at the upper end of the outer cabinet (101). The alarm (605) and the controller (606) are electrically connected. When abnormal pressure, excessive leakage, or excessive temperature and humidity are detected, the controller (606) controls the alarm (605) to issue an audible and visual alarm.

9. A high-efficiency sealed and insulated medium-voltage gas cabinet with low leakage rate according to claim 8, characterized in that: The controller (606) is also connected to the circulating fan (501). When the humidity sensor (602) detects that the humidity inside the inner cabinet (102) is >8% RH, the controller (606) controls the circulating fan (501) to start and run continuously. When the humidity is ≤5% RH, the controller (606) controls the circulating fan (501) to switch to intermittent operation mode.

10. A method of using a low-leakage, high-efficiency, sealed, insulated medium-voltage gas switchgear, based on the low-leakage, high-efficiency, sealed, insulated medium-voltage gas switchgear according to any one of claims 1-9, characterized in that... Includes the following steps: S1. Cabinet sealing assembly: The splicing seam between the outer cabinet (101) and the inner cabinet (102) of the double-layer vacuum cabinet assembly (1) is sealed with copper-based brazing. After assembly, the vacuum chamber (103) between the two is evacuated to a vacuum degree ≤1Pa. The exhaust port is sealed by welding with a metal bellows sealing valve. A labyrinth sealing assembly (3) is installed at the connection between the double-layer vacuum cabinet assembly (1) and the cabinet door (2) to ensure that the labyrinth convex frame (303) and the labyrinth groove (301) are precisely matched. The compression of the fluororubber sealing ring (305) is controlled at 20%-25%. S2. Inlet and outlet line sealing assembly: Insert the sealing tube (403) into the inlet / outlet port (401), apply a polymer sealant layer to the gap between the sealing tube (403) and the inlet / outlet port (401), lock and fix it by two sealing flanges (402) with sealing gaskets, install the insulating thermoplastic sleeve (404) on the outermost sealing flange (402) and complete the thermoplastic sealing of the inlet / outlet; S3, Insulating gas filling: A mixture of dry air and nitrogen with a volume ratio of 7:3 is introduced into the inner cabinet (102) of the double-layer vacuum cabinet assembly (1). The inflation is stopped after the inflation pressure reaches 0.3-0.5MPa. S4. Circulation purification and monitoring operation: Start the monitoring and control component (6) to monitor the pressure, temperature and humidity inside the inner cabinet (102) and the leakage at the sealing connection in real time; when the humidity sensor (602) detects that the humidity is >8% RH, the controller (606) controls the circulation fan (501) of the gas circulation purification component (5) to start and run continuously; when the humidity is ≤5%RH, switch to intermittent operation mode; S5. Exception Handling: When the pressure inside the inner cabinet (102) is <0.3MPa and the leakage is >1×10⁻ 7 When the humidity is greater than 8%RH or m³ / (s・Pa), the controller (606) controls the alarm (605) to issue an audible and visual alarm, stops the machine to check the sealing structure and replenish the insulating gas.

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