A GIS switchgear

Abstract

The application relates to the technical field of power distribution equipment, and discloses a GIS switch device, which comprises a metal cabinet body; an upper secondary control instrument room, a middle full-insulation main switch compartment and a lower cable inlet and outlet line and grounding room are arranged in the metal cabinet body; a fully-closed sealed cavity is arranged in the middle full-insulation main switch compartment; a looped network load switch, a three-position isolating switch, a grounding switch and a high-voltage bus are integrated in the cavity; a high-voltage live part adopts an epoxy resin solid insulation pouring structure; a mechanical five-prevention interlocking mechanism is arranged outside the fully-closed sealed cavity; a sealed transmission seat is arranged on the side wall; an inner transmission shaft, an outer transmission shaft and an elastic sealing piece are arranged in the sealed transmission seat; and the inner transmission shaft and the outer transmission shaft are connected through a spline plug-in transmission structure which can axially slide. Through the above structure, the main circuit is sealed, external mechanical interlocking transmission is realized, and the risks of sealing failure, misoperation and condensation at the transmission wall penetration are reduced.

Description

Technical Field

[0001] This invention relates to the field of power distribution equipment technology, and in particular to a GIS switchgear. Background Technology

[0002] Ring main units (GNUS) are widely used in power distribution networks, primarily for segmentation, interconnection, load control, and cable entry / exit connections of distribution lines. As power distribution equipment evolves towards outdoor deployment, miniaturization, and lower maintenance, higher demands are placed on insulation protection, moisture-proof sealing, operational safety, and ease of on-site maintenance. Traditional gas-insulated metal-enclosed switchgear (GIS) often uses SF6 gas as the insulating medium. While offering excellent insulation performance, it suffers from maintenance challenges such as gas leakage leading to the greenhouse effect, the need for regular gas pressure monitoring, the impact of low-temperature liquefaction on breaking performance, and high costs associated with gas recovery and disposal. When existing GNUS operate outdoors, in coastal, high-humidity, or dusty environments for extended periods, high-voltage live components, busbar connections, and cable termination areas inside the cabinet are susceptible to moisture, dust, condensation, and small animal intrusion, increasing the risk of creepage, flashover, or phase-to-phase short circuits. To ensure insulation safety, some equipment requires a large air insulation clearance, resulting in a less compact internal cabinet layout and hindering installation and use in compact power distribution scenarios.

[0003] In recent years, a technological trend has emerged in this field of replacing gas insulation with solid insulation. While some existing fully insulated or fully enclosed ring network devices can improve insulation performance through solid insulation, sealed cabinets, or partitioned cabinet structures, in actual structures, the sealing space of the high-voltage main circuit still requires the transmission of opening, closing, isolation, and grounding operating forces between the external operating mechanism and the circuit breaker. If the switch operating mechanism passes through the sealed cavity wall for transmission, the point where the transmission passes through the wall can easily become a weak point in the seal. Furthermore, placing too many interlocking or transmission mechanisms inside the sealed cavity increases the complexity of the internal structure, hindering assembly, commissioning, and subsequent maintenance. Simultaneously, during transportation, installation, or long-term operation, the cabinet and switch operating shaft may experience assembly deviations or positional shifts. When the transmission shaft is subjected to skewed forces, it can easily cause wear on the seals, increased transmission resistance, or switch operation jamming.

[0004] Furthermore, regardless of whether it's traditional gas-insulated GIS or solid-insulated ring network switchgear, clear anti-misoperation constraints are needed between the ring network load switch, three-position disconnector, grounding switch, and cable compartment doors during power outages, power restorations, and cable maintenance. In existing equipment, some anti-misoperation structures primarily focus on the operational sequence between switches, lacking sufficient mechanical constraints regarding the closing status of the lower cable entry / exit points and the grounding compartment doors, cable connection status, and power-on operations. If subsequent power restoration or grounding removal operations are still permitted when the cable compartment door is not properly closed, the cable terminal is not reliably connected, or the grounding status does not meet maintenance requirements, it increases the risk of on-site misoperation.

[0005] Meanwhile, there is a certain contradiction between the sealed protection of the cabinet and the convenience of operation and maintenance. The upper secondary control instrument room needs to maintain a relatively independent sealed environment, but daily inspections require reading instrument data and switch status; the lower cable entry and exit and grounding room needs to be protected from small animals, dust and rainwater, but the cable area is prone to condensation due to diurnal temperature differences, load heating and changes in ambient humidity. Therefore, it is necessary to improve the main circuit sealing structure, mechanical interlocking transmission structure, cable plug-in interlocking structure and anti-condensation ventilation structure of the GIS switchgear, so as to overcome the operation and maintenance drawbacks of traditional gas-insulated GIS while maintaining the advantages of the fully enclosed and fully insulated GIS structure. Summary of the Invention

[0006] The technical problem addressed by this invention is twofold: firstly, traditional SF6 gas-insulated GIS switchgear poses risks of greenhouse gas emissions and a burden of gas maintenance; secondly, in existing fully insulated and enclosed ring network switchgear, the high-voltage main circuit needs to be housed within a sealed space, while the load switch, disconnector, and grounding switch require mechanical transmission connections with external operating mechanisms and five-proof interlocking mechanisms, making the transmission parts prone to becoming weak points in the seal; simultaneously, the lack of structured mechanical interlocking relationships between the cable compartment door status, cable connection status, and power transmission operations easily increases the risk of on-site misoperation. The purpose of this invention is to provide a GIS switchgear that replaces traditional SF6 gas insulation with an epoxy resin solid insulation casting structure, maintaining the compact advantages of a fully enclosed and fully insulated GIS structure while eliminating gas leakage and maintenance hazards, achieving a gas-free upgrade of GIS switchgear.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides a GIS switchgear, comprising a metal cabinet with an overall enclosed protective structure. The metal cabinet is divided from top to bottom into three physically isolated sections: an upper secondary control instrument compartment, a middle fully insulated main switch compartment, and a lower cable entry / exit and grounding compartment. The middle fully insulated main switch compartment has a fully enclosed sealed cavity, which integrates a ring network load switch, a three-position disconnect switch, a grounding switch, and a high-voltage busbar. The high-voltage live components within the cavity utilize an epoxy resin solid insulation casting structure. A mechanical five-proof interlocking mechanism is installed outside the fully enclosed sealed cavity. Three sealed transmission seats are located on the side wall of the fully enclosed sealed cavity, corresponding to the ring network load switch, the three-position disconnect switch, and the grounding switch, respectively. Each sealed transmission seat contains an inner transmission shaft, an outer transmission shaft, and an elastic seal. The inner transmission shaft connects to the operating shaft of the corresponding switch, and the outer transmission shaft connects to the mechanical five-proof interlocking mechanism. The inner and outer transmission shafts are connected via an axially sliding spline insertion transmission structure.

[0009] The aforementioned structure centrally arranges the high-voltage main circuit within a fully enclosed sealed cavity, while placing the mechanical five-proof interlocking mechanism outside the cavity. The transmission of operating force between the inside and outside of the cavity is achieved through a sealed transmission seat. The elastic seal within the sealed transmission seat seals the clearance between the transmission shaft and the seat itself. The splined connection transmission structure allows axial sliding between the inner and outer transmission shafts while transmitting rotational operating force. Therefore, the mechanical five-proof interlocking mechanism can drive the internal switching action without entering the fully enclosed sealed cavity, reducing the risk of seal wear and operational jamming at the transmission wall penetration point due to assembly deviations, operational vibrations, or slight deformation of the cabinet.

[0010] Furthermore, the inner drive shaft has an external spline section at the end facing the outer drive shaft, and an internal spline hole at the end facing the inner drive shaft. The external spline section is inserted into the internal spline hole. When the outer drive shaft rotates, the internal spline hole drives the external spline section to rotate synchronously, which in turn drives the inner drive shaft and the operating shaft of the corresponding switch. The external spline section slides axially within the internal spline hole, absorbing axial errors from the fully enclosed sealing cavity, the mechanical five-proof interlocking mechanism, and the operating shafts of each switch during assembly. Through the meshing fit between the external spline section and the internal spline hole, the transmission structure can maintain circumferential transmission while preventing axial errors from being directly transmitted to the elastic seal.

[0011] Furthermore, a detachable sealing door is installed at the front end of the lower cable inlet / outlet and grounding chamber. The mechanical five-proof interlocking mechanism includes a load switch status limiter, an isolation position limiter, a grounding status limiter, and a door lock linkage. The load switch status limiter corresponds to the transmission status of the ring network load switch, the isolation position limiter corresponds to the transmission status of the three-position isolation switch, the grounding status limiter corresponds to the transmission status of the grounding switch, and the door lock linkage cooperates with the detachable sealing door of the lower cable inlet / outlet and grounding chamber. The load switch status limiter, isolation position limiter, grounding status limiter, and door lock linkage are connected by an interlocking slide plate to form a continuous mechanical constraint path. This structure incorporates the switch status and cabinet door status into the same mechanical interlocking path, reducing the uncertainty caused by relying solely on electrical signals or manual judgment.

[0012] Furthermore, when the ring network load switch is in the closed state, the load switch status limiter presses against the isolation position limiter, preventing the three-position disconnector from switching from the working position to the isolation position. When the three-position disconnector has not reached the isolation position, the isolation position limiter restricts the grounding status limiter from operating, preventing the grounding switch from closing. When the grounding switch is in the grounding closed state, the grounding status limiter releases the lock of the removable sealed door of the lower cable inlet / outlet and the grounding chamber via the door lock linkage. When the removable sealed door of the lower cable inlet / outlet and the grounding chamber is not fully closed, the door lock linkage reverses to restrict the grounding switch from releasing the grounding state, preventing the mechanical five-proof interlocking mechanism from releasing the ring network load switch's power-on closing operation. Through the above coordination, the equipment forms a mechanical sequence constraint between power outage, isolation, grounding, door opening, door closing, and power-on.

[0013] Furthermore, the upper secondary control instrument room is an independent, sealed compartment. A removable, sealed door is installed at the front of the upper secondary control instrument room, and a transparent observation window is embedded in the door. A sealed operation panel is fixedly installed inside the upper secondary control instrument room, with the transparent observation window positioned opposite the status display area of ​​the sealed operation panel. An annular sealing strip is installed between the transparent observation window and the removable, sealed door, and the inner edge of the transparent observation window is pressed against the window flange of the removable, sealed door by the annular sealing strip. Operators can observe the operating status without opening the removable, sealed door, reducing the chance of external moisture and dust entering the upper secondary control instrument room.

[0014] Furthermore, the switch position indicator on the sealed operation panel is linked to the actual mechanical position of the mechanical five-proof interlocking mechanism. The switch status displayed on the sealed operation panel corresponds to the mechanical positions of the ring network load switch, the three-position disconnect switch, and the grounding switch. This setting allows the displayed status to be derived from the mechanical interlocking position, reducing the risk of misjudgment when relying solely on electrical signal displays.

[0015] Furthermore, a cable fixing bracket is fixedly installed at the inner end of the lower cable inlet / outlet and grounding chamber. A grounding copper busbar is fixedly installed on one side of the cable fixing bracket, and an insulating sealing sleeve is fixedly installed at the lower end of the cable fixing bracket. The insulating sealing sleeve is a shielded insulating sleeve, which is plugged into the fully insulated, touchable cable plug at the end of the externally introduced cable body. The cable fixing bracket and the insulating sealing sleeve maintain a fixed relative position. After the cable body end is plugged in, the cable fixing bracket bears the self-weight of the cable body and the external tension. This structure separates the cable's stress support from the electrical plug seal, reducing the impact of cable sagging or external pulling on the plug interface of the insulating sealing sleeve.

[0016] Furthermore, a cable insertion interlocking structure is provided on one side of the insulating sealing sleeve, which is linked with the mechanical five-proof interlocking mechanism. The cable insertion interlocking structure includes an insertion clamping component, an insertion push rod, and a power supply locking component. The insertion clamping component corresponds to the clamping state of the fully insulated, touchable cable plug at the end of the cable body. The insertion push rod is pushed by the insertion clamping component, and the power supply locking component restricts the mechanical five-proof interlocking mechanism from releasing the power supply operation. When the fully insulated, touchable cable plug at the end of the cable body is inserted and clamped in place, the insertion clamping component pushes the insertion push rod to move, and the power supply locking component releases the restriction on the mechanical five-proof interlocking mechanism. When the fully insulated, touchable cable plug at the end of the cable body is not inserted or not clamped, the insertion push rod resets, the power supply locking component remains locked, and the mechanical five-proof interlocking mechanism cannot release the closing operation of the ring network load switch. This structure incorporates the cable insertion state into the mechanical restriction conditions before power supply.

[0017] Furthermore, a sealing opening is provided on the lower bottom plate of the lower cable inlet / outlet and grounding chamber, allowing the cable body to pass through into the metal cabinet. The sealing opening features a split-type compression sealing structure, consisting of two elastic sealing blocks and a pressure plate. The two elastic sealing blocks are joined from both sides of the cable body, and the pressure plate presses the two elastic sealing blocks together, causing them to radially conform to the outer circumference of the cable body and axially press against the edge of the sealing opening. Using this split-type compression sealing structure allows for sealing installation even after the cable body has passed through the metal cabinet, facilitating on-site construction and subsequent maintenance.

[0018] Furthermore, a removable sealing door is installed at the front end of the lower cable inlet / outlet and grounding chamber, with an anti-condensation ventilation opening on the door's surface. A metal mesh cover is installed on the inner wall of the anti-condensation ventilation opening. A labyrinth-style breathing anti-condensation structure is installed at the anti-condensation ventilation opening, comprising an outer air intake area, a baffle channel, a dust settling area, a hydrophobic and breathable layer, a condensate drainage channel, and an inner ventilation area. The outer air intake area connects to the outside, while the inner ventilation area connects to the lower cable inlet / outlet and grounding chamber. The baffle channel is located between the outer air intake area and the inner ventilation area. The baffle channel includes an upward baffle section and a downward baffle section, with condensate draining along the condensate drainage channel to the outside of the metal cabinet. By combining the baffle channel, dust settling area, hydrophobic and breathable layer and condensate diversion channel, the external air changes its flow direction before entering the lower cable inlet / outlet and grounding chamber. Water droplets and dust are blocked or settled during the flow, and condensate is discharged through the condensate diversion channel, thus taking into account ventilation, condensation prevention, dust prevention and small animal intrusion prevention.

[0019] In summary, the present invention has at least one of the following beneficial technical effects:

[0020] 1. This invention provides a GIS switchgear that centrally houses the ring network load switch, three-position disconnect switch, grounding switch, and high-voltage busbar within a fully enclosed sealed cavity. The high-voltage live components within the cavity utilize an epoxy resin solid insulation casting structure, achieving the same level of fully enclosed protection as traditional SF6 gas-insulated GIS through solid insulation. This completely eliminates the risk of gas leakage, eliminating the need for pressure gauges and gas recovery treatment, thus upgrading the GIS switchgear towards a gas-free, maintenance-free, and environmentally friendly approach. The high-voltage main circuit is isolated from external moisture, dust, and condensation, reducing the risks of creepage and flashover from exposed live parts. Furthermore, the upper secondary control instrument room, the middle fully insulated main switch compartment, and the lower cable entry / exit and grounding compartment are arranged in separate zones, facilitating equipment assembly, inspection, and operation maintenance.

[0021] 2. This invention arranges the mechanical five-proof interlocking mechanism outside the fully enclosed sealed cavity, and uses a sealed transmission seat, inner transmission shaft, outer transmission shaft, elastic seal, and axially sliding splined connection transmission structure to complete the transmission between the inside and outside of the cavity. This allows the mechanical five-proof interlocking mechanism of the GIS switchgear to drive the corresponding switch action without entering the fully enclosed sealed cavity. The elastic seal maintains the sealed state of the transmission position, and the splined connection transmission structure absorbs axial errors during assembly, reducing the risk of transmission shaft misalignment, seal wear, and switch operation jamming.

[0022] 3. The GIS switchgear of the present invention forms a mechanical constraint path through load switch status limiters, isolation position limiters, grounding status limiters, door lock linkages, and interlocking slides. In conjunction with the cable insertion interlocking structure, the switch status, grounding status, cabinet door closed status, and cable insertion status all participate in power supply restriction. When the lower cable inlet / outlet and grounding chamber do not meet the maintenance or power supply conditions, the mechanical five-proof interlocking mechanism restricts subsequent operations, reducing the risk of misoperation during power outages, power supply, and cable maintenance. Attached Figure Description

[0023] Figure 1 This is a side sectional view of the overall structure of the present invention;

[0024] Figure 2 This is a front view of the overall structure of the present invention;

[0025] Figure 3 This is a bottom view of the overall structure of the present invention.

[0026] The components include: 1. Metal cabinet; 2. Upper secondary control instrument room; 3. Middle fully insulated main switch compartment; 4. Lower cable entry / exit and grounding compartment; 5. Sealed operating panel; 6. Transparent observation window; 7. Fully enclosed sealed cavity; 8. Ring network load switch; 9. Three-position disconnect switch; 10. Grounding switch; 11. High-voltage busbar; 12. Grounding copper busbar; 13. Cable fixing bracket; 14. Insulating sealing sleeve; 15. Sealed plug; 16. Removable sealed door; 17. Anti-condensation ventilation opening; 18. Mechanical five-proof interlocking mechanism; 19. Cable body. Detailed Implementation

[0027] See attached document Figure 1 To be continued Figure 3 As shown, this embodiment discloses a GIS switchgear, specifically a fully insulated and fully enclosed ring network GIS switchgear, including a metal cabinet 1.

[0028] It should be clarified that the GIS switchgear or ring network GIS switchgear referred to in this application does not refer to gas-insulated switchgear that uses SF6 gas as the main insulating medium in the traditional sense, but rather to a new generation of GIS switchgear that uses epoxy resin solid insulation casting technology to achieve full insulation encapsulation of the main circuit. In terms of structure, this equipment inherits the fully enclosed, modular, and physically isolated design concept of GIS, and in terms of insulation, it uses solid insulating materials instead of gas insulating media to achieve an environmentally friendly GIS solution with zero greenhouse gas emissions and no gas pressure monitoring or maintenance. For the sake of brevity, the following will still refer to it as GIS switchgear or this equipment.

[0029] The metal cabinet 1 adopts a one-piece metal armored cabinet structure, and the whole unit adopts a structure combining full insulation of high-voltage live parts with cabinet enclosure protection. The interior of the metal cabinet 1 adopts a modular and partitioned layout, which is divided into the upper secondary control instrument room 2, the middle fully insulated main switch compartment 3, and the lower cable inlet / outlet and grounding compartment 4, which are physically isolated from each other. This allows the secondary control section, the high-voltage main circuit section, and the cable connection and grounding section to be arranged independently, reducing the mutual influence between the functional areas.

[0030] The metal cabinet 1 is an overall enclosed protective structure. The central fully insulated main switch compartment 3 contains a fully enclosed sealed cavity 7, which serves as the high-voltage main circuit sealed cavity. The upper secondary control instrument compartment 2 is an independent sealed compartment. This structure isolates the high-voltage primary energized components from external moisture, dust, condensation, corrosive gases, and small animals, improving the equipment's operational reliability in outdoor, coastal, high-humidity, and dusty environments. The key structural feature of this embodiment is that the high-voltage main circuit is centrally located within the fully enclosed sealed cavity 7, while mechanical operation, interlocking, and maintenance-related components are arranged outside the fully enclosed sealed cavity 7. This preserves the sealed space for the main circuit while facilitating the assembly, debugging, and maintenance of external mechanical mechanisms.

[0031] See attached document Figure 1 As shown, the central fully insulated main switch compartment 3 is equipped with a fully enclosed sealed cavity 7, which integrates a ring network load switch 8, a three-position disconnect switch 9, a grounding switch 10, and a high-voltage busbar 11. The three-position disconnect switch 9 and the grounding switch 10 are connected by a mechanical five-proof interlocking mechanism 18 to achieve operational sequence constraints.

[0032] The fully enclosed sealed cavity 7 also integrates current transformers, voltage transformers, and overvoltage protection devices. The current transformers and voltage transformers are electrically connected to the measurement and control components in the upper secondary control instrument room 2, respectively. The overvoltage protection devices are used to protect the high-voltage main circuit from overvoltage. The ring network load switch 8, three-position disconnect switch 9, grounding switch 10, high-voltage busbar 11, transformers, and overvoltage protection devices are all centrally arranged in the fully enclosed sealed cavity 7, making the main circuit layout relatively compact and facilitating pre-installation and testing in the factory.

[0033] All high-voltage live components within the fully enclosed sealed cavity 7 employ a fully insulated encapsulation structure, ensuring that no live parts are exposed in the high-voltage main circuit inside the metal cabinet 1. Specifically, in this embodiment, the fully insulated encapsulation structure is an epoxy resin solid insulation casting structure. This structure reduces reliance on air insulation clearance and lowers the risk of flashover and creepage caused by moisture, dust, or condensation. The epoxy resin solid insulation casting structure covers the outer periphery of the live connection parts of the ring network load switch 8, the three-position disconnect switch 9, the grounding switch 10, and the high-voltage busbar 11, ensuring continuous insulation connection of each phase's conductive path within the fully enclosed sealed cavity 7, reducing weak points in insulation at end connections, phase transitions, and busbar connection locations.

[0034] See attached document Figure 1 As shown, a mechanical five-proof interlocking mechanism 18 is fixedly installed in the central fully insulated main switch compartment 3. The mechanical five-proof interlocking mechanism 18 is located outside the fully enclosed sealed cavity 7, and is connected to the operating shafts of the ring network load switch 8, the three-position disconnect switch 9, and the grounding switch 10 inside the fully enclosed sealed cavity 7 through a sealed transmission assembly.

[0035] Specifically, three sealing drive seats are respectively installed on the side wall of the fully enclosed sealed cavity 7, corresponding to the ring network load switch 8, the three-position disconnect switch 9, and the grounding switch 10. Each sealing drive seat passes through the wall plate of the fully enclosed sealed cavity 7, and contains an inner drive shaft, an outer drive shaft, and an elastic seal. The inner drive shaft is located inside the fully enclosed sealed cavity 7 and is connected to the operating shaft of the corresponding switch; the outer drive shaft is located outside the fully enclosed sealed cavity 7 and is connected to the mechanical five-proof interlocking mechanism 18; the elastic seal is sleeved on the outer circumference of the drive shaft to seal the fit clearance between the drive shaft and the sealing drive seat.

[0036] The inner and outer drive shafts are connected by a splined joint transmission structure that allows axial sliding. The inner drive shaft has an external splined section at its end facing the outer drive shaft, while the outer drive shaft has an internal splined hole at its end facing the inner drive shaft. The external splined section is inserted into the internal splined hole. When the outer drive shaft rotates, the internal splined hole drives the external splined section to rotate synchronously, thereby actuating the inner drive shaft and the corresponding switch's operating shaft. When a small axial deviation occurs during assembly or operation, the external splined section can slide axially within the internal splined hole without affecting circumferential transmission.

[0037] An elastic seal is pressed between the sealing drive seat and the drive shaft, maintaining the sealed state of the fully enclosed sealing cavity 7 when the drive shaft rotates. Through this structure, the mechanical five-proof interlocking mechanism 18 can mechanically control the switches inside the cavity without entering it. This arrangement reduces the number of mechanisms inside the sealing cavity and also reduces the risk of wear, loosening, air leakage, or moisture ingress at the operating shaft protrusion point due to long-term rotation.

[0038] The axially sliding splined connection transmission structure can also absorb the axial errors of the fully enclosed sealed cavity 7, the mechanical five-proof interlocking mechanism 18, and each switch operating shaft during assembly. When the metal cabinet 1 undergoes slight deformation during transportation, installation, or outdoor operation, the outer spline section can produce a small amount of slippage within the inner spline hole, maintaining a circumferential meshing transmission state. This prevents the operating shaft from being squeezed by force deviation, which could lead to localized wear of the seal or jamming of the switch operation.

[0039] The mechanical five-proof interlocking mechanism 18 is used to achieve forced interlocking between the ring network load switch 8, the three-position disconnect switch 9, the grounding switch 10, and the cabinet door. Specifically, when the ring network load switch 8 is in the closed state, the mechanical five-proof interlocking mechanism 18 restricts the three-position disconnect switch 9 from performing isolation switching operations to prevent disconnection and isolation under load; when the grounding switch 10 is in the grounding closed state, the mechanical five-proof interlocking mechanism 18 restricts the ring network load switch 8 from entering the energized closed state to prevent energized closing; when the three-position disconnect switch 9 is not in the specified position, the mechanical five-proof interlocking mechanism 18 restricts the corresponding switch mechanism from continuing to operate to prevent accidental disconnection or closing; when the removable sealing door 16 of the lower cable inlet / outlet and the grounding chamber 4 is not closed in place, the mechanical five-proof interlocking mechanism 18 restricts energization operations to prevent accidental entry into the energized compartment.

[0040] Furthermore, the mechanical five-proof interlocking mechanism 18 includes a load switch status limiter, an isolation position limiter, a grounding status limiter, and a door lock linkage. The load switch status limiter corresponds to the transmission state of the ring network load switch 8, the isolation position limiter corresponds to the transmission state of the three-position isolation switch 9, the grounding status limiter corresponds to the transmission state of the grounding switch 10, and the door lock linkage cooperates with the detachable sealing door 16 of the lower cable inlet / outlet and grounding chamber 4. The above-mentioned limiters and door lock linkage are connected by an interlocking sliding plate to form a continuous mechanical constraint path.

[0041] When the ring network load switch 8 is in the closed position, the load switch status limit element presses against the isolation position limit element, and the three-position disconnect switch 9 cannot switch from the working position to the isolation position. After the ring network load switch 8 is opened, the load switch status limit element is released, and only then can the three-position disconnect switch 9 perform isolation switching.

[0042] When the three-position disconnector 9 is not in the isolation position, the isolation position limiter restricts the grounding state limiter from operating, and the grounding switch 10 cannot be closed. After the three-position disconnector 9 reaches the isolation position, the isolation position limiter releases the grounding state limiter, and the grounding switch 10 is then allowed to close. Through the above coordination, before the equipment enters the maintenance state, the load tripping, isolation disconnection, and grounding closing need to be completed sequentially.

[0043] When the grounding switch 10 is in the grounding closed state, the grounding status limit device releases the lock of the detachable sealing door 16 of the lower cable inlet / outlet and grounding chamber 4 through the door lock linkage, allowing maintenance personnel to open the lower cable inlet / outlet and grounding chamber 4. When the grounding switch 10 is not in the grounding closed state, the door lock linkage remains locked, and the detachable sealing door 16 of the lower cable inlet / outlet and grounding chamber 4 cannot be opened.

[0044] When the removable sealing door 16 of the lower cable inlet / outlet and grounding chamber 4 is not fully closed, the door lock linkage reverse limit grounding switch 10 is released from the grounding state, and the mechanical five-proof interlocking mechanism 18 cannot release the energizing and closing operation of the ring network load switch 8. In this way, a mechanical sequence constraint is formed between switch opening / closing, isolation, grounding, door opening, and energizing, reducing the risk of misoperation caused by relying solely on electrical interlocking or manual confirmation.

[0045] The fully enclosed sealed cavity 7 and the metal cabinet 1 are also equipped with internal fault relief structures at predetermined pressure relief locations. When a fault arc or abnormal pressure rise occurs inside the fully enclosed sealed cavity 7, the fault pressure can be released in a predetermined direction, thereby reducing the risk of cabinet deformation and accident escalation. The pressure relief direction of the internal fault relief structure avoids the operation and observation area of ​​the upper secondary control instrument room 2 and the maintenance opening direction of the lower cable inlet / outlet and grounding chamber 4, in order to reduce the impact of fault pressure on operators and secondary control components.

[0046] See attached document Figure 1 and appendix Figure 2 As shown, the upper secondary control instrument compartment 2 is an independent sealed compartment, with a sealed operation panel 5 fixedly installed inside. The upper secondary control instrument compartment 2 houses a microprocessor-based protection device, a measurement and control unit, metering instruments, status indicator lights, a switching mechanism, secondary terminal blocks, and a communication interface. The communication interface is used for telemetry, telesignaling, or remote control communication with the power distribution automation backend or remote monitoring system. The upper secondary control instrument compartment 2 also contains dehumidification components, temperature control components, and a sealed wiring structure. Secondary cables are connected to corresponding detection or control elements in the central fully insulated main switch compartment 3 via sealed wiring components to prevent moisture from entering the secondary control area through the wiring locations.

[0047] A removable sealed door 16 is installed at the front end of the upper secondary control instrument room 2, and a transparent observation window 6 is embedded in the removable sealed door 16. The sealed operation panel 5 is provided with a status display area and an operation control area; when the removable sealed door 16 is in the closed state, the transparent observation window 6 is positioned directly opposite the status display area, so that the operator can observe the instrument data, switch status, and fault alarm information without opening the door; when the removable sealed door 16 is in the open state, the operation control area of ​​the sealed operation panel 5 is exposed, forming an operating space for opening and closing, resetting, parameter setting, or maintenance operations on the sealed operation panel 5. Thus, while ensuring the sealed protection of the upper secondary control instrument room 2, the convenience of equipment inspection and operation is improved.

[0048] A ring-shaped sealing strip is provided between the transparent observation window 6 and the removable sealing door 16, and the inner edge of the transparent observation window 6 is pressed against the window flange of the removable sealing door 16. Operators can read the operating status information on the sealing operation panel 5 without opening the removable sealing door 16, reducing moisture ingress caused by frequent door opening. The switch position indicator on the sealing operation panel 5 is linked to the actual mechanical position of the mechanical five-proof interlocking mechanism 18, ensuring that the displayed status corresponds to the switch mechanical position and avoiding misjudgments caused by relying solely on electrical signal displays.

[0049] See attached document Figure 1 and appendix Figure 3 As shown, the lower cable inlet / outlet and grounding chamber 4 is located at the bottom of the metal cabinet 1, used for bottom-entry and bottom-outlet wiring, fixing, and grounding of the cable body 19. A sealing opening 15 is provided on the lower bottom plate of the lower cable inlet / outlet and grounding chamber 4, allowing the cable body 19 to pass through into the cabinet. A sealing structure is provided at the sealing opening 15. After the cable body 19 passes through the sealing opening 15, the sealing structure presses tightly around the outer periphery of the cable body 19 to seal the gap between the cable body 19 and the sealing opening 15, thereby ensuring the sealing and protection performance of the cable entry point.

[0050] The sealing and plugging structure adopts a split-type compression sealing structure, which includes two elastic sealing blocks and a pressure plate. The two elastic sealing blocks are spliced ​​from both sides of the cable body 19, and the pressure plate presses the two elastic sealing blocks together, so that the elastic sealing blocks are radially fitted to the outer periphery of the cable body 19 and axially pressed against the edge of the sealing and plugging opening 15. With this structure, the bottom sealing installation can be completed even when the cable body 19 has been inserted into the cabinet, which facilitates on-site construction and subsequent maintenance.

[0051] A cable fixing bracket 13 is fixedly installed at the inner end of the lower cable inlet / outlet and grounding chamber 4. The cable fixing bracket 13 is used to position and support the cable body 19 to prevent the cable body 19 from affecting the wiring reliability due to its own weight or external pulling force. A grounding copper busbar 12 is fixedly installed on one side of the cable fixing bracket 13. The grounding copper busbar 12 is used to connect with the grounding circuit of the cable shielding layer, the metal cabinet 1, and the grounding switch 10 to form a reliable protective grounding channel.

[0052] The cable fixing bracket 13 and the insulating sealing sleeve 14 maintain a fixed relative position. After the cable body 19 is inserted at the end, the cable fixing bracket 13 bears the weight of the cable body 19 and the external tension, while the insulating sealing sleeve 14 mainly bears the electrical connection and sealing connection. This stress separation structure can reduce the impact of the cable body 19 falling or being pulled on the insulating sealing sleeve 14, and reduce the risk of loosening of the insertion interface, sealing failure or partial discharge.

[0053] An insulating sealing sleeve 14 is fixedly installed at the lower end of the cable fixing bracket 13. The insulating sealing sleeve 14 is configured to plug into the externally introduced cable body 19 to achieve a sealed connection. Specifically, the insulating sealing sleeve 14 is a shielded insulating sleeve. The end of the cable body 19 is provided with a fully insulated touchable cable plug that is compatible with the insulating sealing sleeve 14. After the fully insulated touchable cable plug is plugged into the insulating sealing sleeve 14, a sealed and insulated connection structure is formed, so that there are no exposed high-voltage live parts at the cable connection end. Through this structure, a continuous and fully insulated connection can be formed between the cable access area and the high-voltage main circuit in the fully enclosed sealed cavity 7, avoiding the risk of electric shock, creepage, or short circuits caused by exposed cable ends.

[0054] Furthermore, a cable insertion interlocking structure is provided on one side of the insulating sealing sleeve 14, which is linked with the mechanical five-proof interlocking mechanism 18. The cable insertion interlocking structure includes an insertion clamping member, an insertion push rod, and a power supply locking member. The insertion clamping member corresponds to the clamping state of the plug at the end of the cable body 19, the insertion push rod is pushed by the insertion clamping member, and the power supply locking member is used to restrict the release of the mechanical five-proof interlocking mechanism 18.

[0055] After the fully insulated, touchable cable plug at the end of the cable body 19 is fully inserted into the insulating sealing sleeve 14 and pressed tightly, the insertion clamping component pushes the insertion positioning push rod to move, and the power supply locking component releases the restriction on the mechanical five-proof interlocking mechanism 18. At this time, if other five-proof conditions are met, the equipment is allowed to disconnect the grounding and be powered on.

[0056] When the fully insulated, touchable cable plug at the end of the cable body 19 is not properly inserted, not tightened, or becomes loose, the insertion push rod resets, the power-on locking element remains locked, and the mechanical five-proof interlocking mechanism 18 cannot release the closing operation of the ring network load switch 8. This structure is used to reduce the risk of accidental power supply when the cable terminal is not fully inserted, the shielding grounding is not reliably formed, or the sealing interface is not in place.

[0057] See attached document Figure 2 As shown, another removable sealing door 16 is also installed at the front end of the lower cable inlet / outlet and grounding chamber 4. An anti-condensation ventilation opening 17 is provided on the surface of this lower removable sealing door 16. The anti-condensation ventilation opening 17 is a protective ventilation structure, with a metal mesh cover installed on the inner wall of the anti-condensation ventilation opening 17 to prevent small animals from entering the lower cable inlet / outlet and grounding chamber 4 through the anti-condensation ventilation opening 17. The anti-condensation ventilation opening 17 serves to achieve air pressure balance between the inside and outside of the cable compartment and to prevent condensation ventilation while blocking external rainwater, dust, and large particulate impurities from entering. Therefore, the anti-condensation ventilation opening 17 does not compromise the overall sealing and protective performance of the equipment and can improve the moisture-proof and anti-condensation capabilities of the lower cable inlet / outlet and grounding chamber 4.

[0058] Furthermore, 17 anti-condensation vents are equipped with a labyrinth-style breathing anti-condensation structure. This structure includes an outer air intake area, a baffle channel, a dust settling area, a hydrophobic and breathable layer, a condensate drainage channel, and an inner ventilation area. The outer air intake area connects to the outside environment, while the inner ventilation area connects to the lower cable inlet / outlet and grounding chamber 4. The baffle channel is located between the outer air intake area and the inner ventilation area. The baffle channel includes an upward baffle section and a downward baffle section, preventing outside air from entering the lower cable inlet / outlet and grounding chamber 4 in a straight line.

[0059] After entering the anti-condensation vent 17, the outside air first changes its flow direction through the deflection channel. Dust and water droplets carried in the air settle or adhere to the dust settling area during the deflection process. Water vapor forms condensate under the action of temperature difference and is discharged to the outside of the cabinet along the condensate guide channel. After passing through the hydrophobic and breathable layer, the air then enters the lower cable inlet / outlet and grounding chamber 4 to balance the internal and external air pressure and alleviate local condensation.

[0060] Through the labyrinthine breathing anti-condensation structure, the lower cable inlet / outlet and grounding chamber 4 retains the ability to be waterproof, dustproof and prevent small animals from entering, while releasing some of the moisture generated by day-night temperature differences, load heating or changes in ambient humidity, reducing the possibility of condensation and surface creep in the cable terminal area.

[0061] The bottom of the metal cabinet 1 is also equipped with a mounting and fixing structure to ensure the equipment is installed stably. Since the high-voltage main circuit adopts a fully insulated encapsulated structure and is centrally located in the fully enclosed sealed cavity 7, and the upper secondary control instrument room 2, the middle fully insulated main switch compartment 3, and the lower cable inlet / outlet and grounding compartment 4 are arranged in a modular physical isolation manner, this embodiment can improve insulation safety, environmental adaptability, and ease of operation and maintenance while reducing the cabinet size.

[0062] In this embodiment, the fully insulated and enclosed ring network switchgear can complete the main circuit insulation encapsulation, secondary control wiring, mechanical five-proof interlocking mechanism 18 commissioning, and overall cabinet sealing test in the factory. During on-site installation, the main tasks are to connect the cable body 19 to the insulating sealing sleeve 14, connect the grounding copper busbar 12, and connect the communication interface, resulting in minimal on-site wiring and commissioning work. After the equipment is put into operation, operators can view the status information on the sealed operation panel 5 through the transparent observation window 6 and restrict erroneous operation sequences through the mechanical five-proof interlocking mechanism 18.

[0063] During the overall cabinet commissioning process, the sealing of the fully enclosed sealed cavity 7 is tested first. Then, the transmission resistance, axial slippage, and sealing status at the sealing transmission seat are checked. Next, the linkage between the mechanical five-proof interlocking mechanism 18 and the ring network load switch 8, the three-position disconnecting switch 9, the grounding switch 10, the lower detachable sealing door 16, and the cable insertion interlocking structure are verified item by item. After the above checks, the comprehensive verification of insulation sealing, mechanical interlocking, and cable access safety conditions can be completed before the equipment leaves the factory, reducing the risk of incorrect wiring, incorrect commissioning, and incorrect operation on site.

[0064] Working Principle: During normal operation of this GIS switchgear, the electrical energy from the high-voltage busbar 11 is sequentially transmitted to the insulating bushing 14 via the three-position disconnector 9 and the ring network load switch 8 within the central fully insulated main switch compartment 3, and then output through the externally introduced cable body 19. During this process, the high-voltage energized components are housed within the fully enclosed sealed cavity 7. The insulating plug at the end of the cable body 19 is inserted into the insulating bushing 14, forming a continuous insulating channel to block phase-to-phase and phase-to-ground discharge paths. Simultaneously, the sealing port 15 at the bottom of the metal cabinet 1 and the removable sealing doors 16 of each compartment are closed, preventing external moisture and dust. The air in the lower cable inlet / outlet and grounding chamber 4 is connected to the outside through the anti-condensation ventilation port 17 to balance air pressure and humidity. The inner metal isolation mesh cover prevents small animals from entering, maintaining a stable insulating environment within the cabinet.

[0065] During high-voltage main circuit operation, the operating force applied by the operator to the mechanical five-proof interlocking mechanism 18 is transmitted to the operating shaft of the corresponding switch inside the cavity via the outer drive shaft outside the fully enclosed sealed cavity 7, the axially sliding splined insertion transmission structure, and the inner drive shaft. The elastic seal maintains a sealed and compressed state at the sealing transmission seat during the rotation of the drive shaft, allowing the mechanical operating force to be transmitted through the cavity wall of the fully enclosed sealed cavity 7, while preventing the formation of channels for moisture, dust, or corrosive gases to enter the main circuit sealed space.

[0066] When the equipment switches states, the mechanical five-proof interlocking mechanism 18 constrains the operating sequence of the switching mechanism. During power outage and grounding operations, the ring network load switch 8 is first disconnected to cut off the main circuit. The mechanical five-proof interlocking mechanism 18 then releases the lock on the three-position disconnecting switch 9, allowing it to be switched to the disconnected position. Subsequently, the grounding switch 10 is closed, connecting the lower cable circuit to the grounding copper busbar 12, completing the protective grounding. During power-on operations, when the grounding switch 10 is closed, the mechanical five-proof interlocking mechanism 18 restricts the operating shafts of the ring network load switch 8 and the three-position disconnecting switch 9 to prevent closing with the grounding wire connected. When the ring network load switch 8 is closed, the mechanical five-proof interlocking mechanism 18 locks the transmission part of the three-position disconnecting switch 9 to prevent opening and closing the disconnecting switch under load.

[0067] When inspecting the lower cable inlets / outlets and grounding chamber 4, the mechanical five-prevention interlocking mechanism 18 will only release the lock of the lower removable sealing door 16 after the ring network load switch 8 is open, the three-position isolating switch 9 is in the isolated position, and the grounding switch 10 is closed. If the grounding switch 10 is not reliably closed, the lower removable sealing door 16 remains locked, preventing maintenance personnel from opening the cable connection area. After maintenance, if the lower removable sealing door 16 is not fully closed, the mechanical five-prevention interlocking mechanism 18 will still restrict the opening of the grounding switch 10 and the closing of the ring network load switch 8 to prevent accidental energization while the cable chamber is open.

[0068] Meanwhile, when the fully insulated, touchable cable plug at the end of the cable body 19 is not fully inserted into the insulating sealing sleeve 14, the cable insertion interlock structure maintains the power supply restriction on the mechanical five-proof interlock mechanism 18, and the equipment cannot perform the power supply and closing operation. Only after the cable plug is inserted into place and pressed tightly will the cable insertion interlock structure release the power supply restriction. In this way, a continuous mechanical constraint is formed between the cable insertion state, the grounding state, the door closed state, and the switch energized state.

[0069] During routine inspections, personnel can directly view the operating data and position indicators on the internal sealed operation panel 5 through the transparent observation window 6 at the front of the upper secondary control instrument room 2. Before opening the lower cable inlet / outlet and grounding chamber 4 for maintenance, the grounding switch 10 must be in the grounding closed state before the mechanical five-proof interlocking mechanism 18 can release the lock on the lower removable sealed door 16. After maintenance is completed, if the lower removable sealed door 16 is not closed properly, the mechanical five-proof interlocking mechanism 18 will continue to lock the operating circuit, restricting the grounding release and power-on closing operations to prevent accidental entry into a live compartment.

[0070] When this GIS switchgear is operated outdoors for extended periods, the labyrinthine breathing anti-condensation structure at the anti-condensation vent 17 slowly balances the air pressure according to changes in ambient and cabinet temperatures. Upon entry of hot, humid external air, it is slowed and redirected through the baffle channel, where water droplets and dust are blocked. When internal moisture condenses upon encountering the condensate, the condensate is discharged outside the cabinet along the condensate drain channel, reducing the risk of condensation forming at the lower cable inlets / outlets and in the grounding chamber 4, and the risk of creeping along the cable terminals.

[0071] 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 claims and their equivalents.

Claims

1. A GIS switchgear, characterized in that, It includes a metal cabinet (1) with an overall enclosed protective structure. The metal cabinet (1) is divided from top to bottom into an upper secondary control instrument room (2), a middle fully insulated main switch compartment (3), and a lower cable entry and exit and grounding compartment (4), which are physically isolated from each other. The central fully insulated main switch compartment (3) is equipped with a fully enclosed sealed cavity (7). The fully enclosed sealed cavity (7) integrates a ring network load switch (8), a three-position disconnect switch (9), a grounding switch (10), and a high-voltage busbar (11). The high-voltage live components inside the cavity adopt an epoxy resin solid insulation casting structure. The fully enclosed sealed cavity (7) is equipped with a mechanical five-proof interlocking mechanism (18) on the outside. The side wall of the fully enclosed sealed cavity (7) is equipped with three sealing transmission seats. The three sealing transmission seats correspond to the ring network load switch (8), the three-position isolation switch (9) and the grounding switch (10) respectively. Each sealing transmission seat is equipped with an inner transmission shaft, an outer transmission shaft and an elastic seal. The inner transmission shaft is connected to the operating shaft of the corresponding switch, and the outer transmission shaft is connected to the mechanical five-proof interlocking mechanism (18). The inner transmission shaft and the outer transmission shaft are connected by a spline insertion transmission structure that can slide axially.

2. The GIS switchgear according to claim 1, characterized in that, The inner drive shaft has an external spline section at one end facing the outer drive shaft, and an internal spline hole at the other end facing the inner drive shaft. The external spline section is inserted into the internal spline hole. When the outer drive shaft rotates, the inner spline hole drives the outer spline segment to rotate synchronously, which in turn drives the inner drive shaft and the corresponding switch's operating shaft to move. The external spline section slides axially within the internal spline hole, absorbing the axial errors of the fully enclosed sealed cavity (7), the mechanical five-proof interlocking mechanism (18), and each switch operating shaft during assembly.

3. A GIS switchgear according to claim 1, characterized in that, The front end of the lower cable inlet / outlet and grounding chamber (4) is equipped with a detachable sealing door (16). The mechanical five-proof interlocking mechanism (18) includes a load switch status limiter, an isolation position limiter, a grounding status limiter and a door lock linkage. The load switch status limiter corresponds to the transmission state of the ring network load switch (8), the isolation position limiter corresponds to the transmission state of the three-position isolation switch (9), the grounding status limiter corresponds to the transmission state of the grounding switch (10), and the door lock linkage component cooperates with the detachable sealing door (16) of the lower cable inlet / outlet and grounding chamber (4). The load switch status limiter, isolation position limiter, grounding status limiter, and door lock linkage are connected by an interlocking slide plate to form a continuous mechanical constraint path.

4. A GIS switchgear according to claim 3, characterized in that, When the ring network load switch (8) is in the closed state, the load switch status limiter presses against the isolation position limiter, and the three-position disconnect switch (9) cannot switch from the working position to the isolation position; When the three-position disconnector (9) has not reached the isolation position, the isolation position limiter restricts the grounding state limiter from operating, and the grounding switch (10) cannot be closed. When the grounding switch (10) is in the grounding closed state, the grounding state limit device releases the lock of the detachable sealing door (16) of the lower cable inlet and outlet and the grounding chamber (4) through the door lock linkage device; When the removable sealing door (16) of the lower cable inlet / outlet and grounding chamber (4) is not closed in place, the reverse limiting grounding switch (10) of the door lock linkage is released from the grounding state, and the mechanical five-proof interlocking mechanism (18) cannot release the power supply and closing operation of the ring network load switch (8).

5. A GIS switchgear according to claim 4, characterized in that, The upper secondary control instrument room (2) is an independent sealed compartment. A detachable sealed door (16) is installed at the front end of the upper secondary control instrument room (2). A transparent observation window (6) is embedded in the detachable sealed door (16). A sealed operating panel (5) is fixedly installed in the internal space of the upper secondary control instrument room (2); A transparent observation window (6) is positioned directly opposite the status display area of ​​the sealed operation panel (5); An annular sealing strip is provided between the transparent observation window (6) and the removable sealing door (16). The inner edge of the transparent observation window (6) is pressed against the window flange of the removable sealing door (16) by the annular sealing strip.

6. A GIS switchgear according to claim 5, characterized in that, The switch position indicator on the sealed operation panel (5) is linked to the actual mechanical position of the mechanical five-proof interlocking mechanism (18). The switch status displayed on the sealed operation panel (5) corresponds to the mechanical position of the ring network load switch (8), the three-position disconnect switch (9), and the grounding switch (10).

7. A GIS switchgear according to claim 1, characterized in that, A cable fixing bracket (13) is fixedly installed at the inner end of the lower cable inlet / outlet and grounding chamber (4). A grounding copper busbar (12) is fixedly installed on one side of the cable fixing bracket (13). An insulating sealing sleeve (14) is fixedly installed at the lower end of the cable fixing bracket (13). The insulating sealing sleeve (14) is a shielded insulating sleeve, and the insulating sealing sleeve (14) is connected to the fully insulated touchable cable plug at the end of the externally introduced cable body (19). The cable fixing bracket (13) and the insulating sealing sleeve (14) maintain a fixed relative position. After the end of the cable body (19) is inserted, the cable fixing bracket (13) bears the self-weight and external tension of the cable body (19).

8. A GIS switchgear according to claim 7, characterized in that, One side of the insulating sealing sleeve (14) is provided with a cable insertion interlocking structure, which is linked with the mechanical five-proof interlocking mechanism (18); The cable insertion interlocking structure includes an insertion clamping component, an insertion push rod, and a power supply locking component; The clamping state of the plug-in clamping member corresponds to the fully insulated touchable cable plug at the end of the cable body (19). The plug-in push rod is pushed by the plug-in clamping member, and the power supply locking member restricts the mechanical five-proof interlocking mechanism (18) from releasing the power supply operation. When the fully insulated touchable cable plug at the end of the cable body (19) is inserted into the position and pressed and fixed, the insertion clamping part pushes the insertion push rod to move, and the power supply locking part releases the restriction on the mechanical five-proof interlocking mechanism (18). When the fully insulated touchable cable plug at the end of the cable body (19) is not plugged in or not pressed, the plugging push rod is reset, the power supply locking device remains locked, and the mechanical five-proof interlocking mechanism (18) cannot release the closing operation of the ring network load switch (8).

9. A GIS switchgear according to claim 7, characterized in that, A sealing port (15) is provided on the bottom plate of the lower cable inlet / outlet and grounding chamber (4). The sealing port (15) allows the cable body (19) to pass into the metal cabinet (1). A split-type compression sealing structure is provided at the sealing and plugging port (15). The split-type compression sealing structure includes two elastic sealing blocks and a pressure plate. Two elastic sealing blocks are joined from both sides of the cable body (19), and the pressure plate presses the two elastic sealing blocks so that the elastic sealing blocks are radially attached to the outer periphery of the cable body (19) and axially pressed against the edge of the sealing and plugging opening (15).

10. A GIS switchgear according to claim 3, characterized in that, A removable sealing door (16) is installed at the front end of the lower cable inlet / outlet and grounding chamber (4), and an anti-condensation ventilation opening (17) is provided on the plate surface of the removable sealing door (16). A metal mesh cover is installed on the inner wall of the anti-condensation vent (17); A labyrinth-type breathing anti-condensation structure is provided at the anti-condensation vent (17). The labyrinth-type breathing anti-condensation structure includes an outer air intake area, a baffle channel, a dust settling area, a hydrophobic and breathable layer, a condensate guide channel, and an inner ventilation area. The outer air intake area is connected to the outside, and the inner ventilation area is connected to the lower cable inlet and outlet and the grounding chamber (4). The baffle channel is located between the outer air intake area and the inner ventilation area. The baffle channel includes an upward baffle section and a downward baffle section, and the condensate is discharged along the condensate guide channel to the outside of the metal cabinet (1).

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