Modular small draw-out low voltage switchgear

Abstract

The application belongs to the technical field of power distribution equipment, and particularly relates to a modular small-sized draw-out low-voltage switch cabinet, which comprises a cabinet frame, side plates are fixedly installed at both sides of the rear end of the cabinet frame, and a maintenance protection mechanism is installed in the rear opening of the cabinet frame; in a non-maintenance state, the maintenance protection mechanism is used for plugging the rear opening of the cabinet frame to reduce the exposed area of the electrical structure inside the cabinet frame; and in a maintenance state, the maintenance protection mechanism opens the maintenance window on the rear side of the cabinet frame according to the maintenance position. The maintenance protection mechanism is arranged, the flexible belt covers the rear opening of the cabinet in normal operation, and the charged part in the adjacent non-maintenance functional unit inside the cabinet is isolated, the flexible belt is driven to translate by the winding shaft in maintenance, only the maintenance opening is aligned with the compartment to be maintained, and the remaining area remains plugged and isolated, so that the defect that the whole rear door of the traditional structure is opened to expose the non-maintenance area is avoided, and the safety hidden danger of accidental touch of the maintenance personnel is reduced.

Description

Technical Field

[0001] This invention belongs to the field of power distribution equipment technology, specifically relating to a modular small withdrawable low-voltage switchgear. Background Technology

[0002] Withdrawable low-voltage switchgear is a widely used power distribution equipment in low-voltage power distribution systems. Its cabinet is usually divided into multiple compartments to install live components such as switching elements and conductive busbars. A protective structure is set on the rear side of the cabinet to close the cabinet and isolate the live area during normal operation, while meeting the opening requirements during maintenance.

[0003] Currently, some withdrawable low-voltage switchgear uses an integrated rear door structure: under normal operation, the rear door is closed to achieve enclosed protection of the rear of the cabinet; when maintenance is required on a certain compartment, the entire rear door must be opened, exposing the energized compartments inside the cabinet to the external environment. Even if the maintenance work is only carried out on a single compartment, the remaining energized parts inside will also be exposed without any shielding, expanding the range of energized exposure during maintenance. Maintenance personnel are prone to accidentally touching energized components in adjacent compartments during the work, posing a certain risk of electric shock.

[0004] To solve the above problems, it is necessary to design a modular, small withdrawable low-voltage switchgear that can open only the target compartment while keeping the rest of the area isolated during fixed-point maintenance. Summary of the Invention

[0005] This invention provides a modular miniature withdrawable low-voltage switchgear to solve the problem that existing withdrawable low-voltage switchgear uses an integral rear door, which requires the rear door to be fully opened when maintaining a single compartment, exposing non-maintenance areas and making maintenance personnel prone to accidentally touching live parts, resulting in a high risk of electric shock.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A modular, small withdrawable low-voltage switchgear includes a cabinet frame. Side plates are fixedly installed on both rear ends of the cabinet frame. The rear side of the cabinet frame has an opening structure, and the opening is located between the two side plates. A maintenance protection mechanism is installed inside the opening on the rear side of the cabinet frame. In the non-maintenance state, the maintenance protection mechanism is used to block the opening on the rear side of the cabinet frame to reduce the exposed area of ​​the internal electrical structure of the cabinet frame. In the maintenance state, the maintenance protection mechanism opens the maintenance window on the rear side of the cabinet frame according to the maintenance location.

[0007] An opening is provided on one side of the side panel, and an arc guiding mechanism is installed in the opening. When an internal arc occurs in the cabinet frame, the heat is released through the arc guiding mechanism.

[0008] Preferably, the maintenance and protection mechanism includes a winding shaft spaced vertically, with the ends of the winding shafts rotatably mounted on a side plate. Both ends of the winding shafts are fixedly fitted with annular baffles. A flexible belt is provided between the two winding shafts, with the ends of the flexible belt fixedly connected to and wound onto the winding shafts. The annular baffles on both sides laterally limit the movement of the flexible belt. Two servo motors are fixedly mounted on the side plate, with their output shafts respectively fixedly connected to the winding shafts. A controller is fixedly mounted on the side plate to control the operation of the two servo motors. An inspection port is provided on the flexible belt, penetrating the flexible belt, and the cabinet frame is in an open state through the inspection port.

[0009] In the above solution, through the cooperation of the winding shaft and the flexible belt, the flexible belt achieves vertical translational movement under the drive of the servo motor. The inspection port moves accordingly to align with the target compartment, while the solid part of the flexible belt still blocks the non-inspection area, avoiding the problem of exposing the non-inspection area when the entire rear door is fully opened in the traditional method. The annular baffle forms a limiting constraint on both sides of the flexible belt, further improving the operational reliability. The controller controls the two servo motors to move synchronously, which can adjust the longitudinal position of the inspection port so that the inspection window is aligned with the target compartment, meeting the fixed-point maintenance requirements of the multi-layer structure of the modular small switchgear.

[0010] Preferably, the arc guiding mechanism includes multiple arc-shaped plates located within the opening, the multiple arc-shaped plates are arranged equidistantly from top to bottom, and circular pieces are fixedly installed on both sides of each arc-shaped plate. The arc-shaped plates and the circular pieces on both sides form a storage space, and a connecting shaft is fixedly installed on each circular piece. The end of the connecting shaft is rotatably installed on the side plate.

[0011] In the above scheme, a certain storage space is formed by multiple arc-shaped plates arranged at equal intervals on the top and bottom and circular plates on both sides. When an electric arc fault occurs inside the cabinet, the airflow enters the storage space through the opening. The arc surface of the arc plate guides the lateral impact airflow to be released from the upper port of the storage space to the outside of the cabinet, forming a pressure relief path for the fault gas to enter the guide channel through the lateral opening and exhaust upward. At the same time, solid residues such as molten slag and conductive carbon slag carried by the airflow are gradually deposited and retained in the storage space under the obstruction of the arc surface of the arc plate and the action of its own gravity, preventing the residues from splashing around with the airflow and contaminating the components inside the cabinet or injuring external personnel.

[0012] Preferably, the arc guiding mechanism further includes an adjusting component, which includes a guide rod disposed within the cabinet frame and fixedly mounted on the side plate. A movable rod is provided within the cabinet frame, and a sliding groove is formed on the movable rod. One end of the guide rod extends into the sliding groove, and the movable rod is slidably mounted on the guide rod. A base plate is fixedly mounted at the bottom of the guide rod, and the base plate is used to limit the downward movement of the movable rod. Anti-slip textures are distributed on the outer surface of the circular pieces. A drive strip is fixedly mounted on the movable rod, and anti-slip particles are distributed on the surface of the drive strip. The drive strip abuts against the anti-slip textures on the multiple circular pieces, forming a frictional transmission engagement.

[0013] In the above scheme, by sliding the movable rod up and down, the anti-slip particles on the surface of the drive bar and the anti-slip texture on the outer surface of the disc generate static friction, thereby synchronously driving all the arc plates to rotate around the connecting shaft, realizing the linkage adjustment of the angle of multiple arc plates. It is not necessary to set a separate drive source for each layer of arc plates, simplifying the structure. The guide rod and the slide groove cooperate to constrain the movement direction of the movable rod, and the base plate limits the lower limit position of the movable rod, ensuring the stability and reliability of the adjustment action.

[0014] Preferably, the maintenance and protection mechanism further includes a flexible magnet, which is embedded in a flexible strip and distributed along the length of the flexible strip. The flexible magnet is positioned towards the movable rod, and multiple electromagnets are fixedly installed on the movable rod at equal vertical distances. When the electromagnets are energized, they are in contact with the flexible magnets. The electromagnets are controlled by a controller. In the slag removal state, the maintenance and protection mechanism drives the movable rod to move through the attraction between the flexible magnets and the electromagnets, and controls the switching of the working angle of the arc guiding mechanism to the slag discharge position.

[0015] In the above scheme, when the flexible belt moves, the flexible magnet will move synchronously with the flexible belt. After the electromagnet is energized, it will attract the flexible magnet, so that a magnetic connection is formed between the flexible belt and the movable rod. The winding action of the flexible belt can drive the movable rod to slide up and down through the magnetic attraction, thereby triggering the adjustment component to switch the angle of the arc plate. This realizes the linkage control between the maintenance protection mechanism and the arc guiding mechanism. There is no need to set up an additional independent drive device to operate the arc plate. The structure is more compact and the control logic is clear.

[0016] Preferably, the upper port of the storage space is exposed outside the cabinet frame.

[0017] In the above solution, the upper port of the storage space is directly exposed to the outside of the cabinet. During normal operation, this port serves as a heat dissipation outlet, utilizing the flow channel formed by the curved surface of the arc plate and the chimney effect to assist in the discharge of heat from inside the cabinet, achieving passive auxiliary heat dissipation. In the event of an arc fault, this upper port serves as a directional pressure relief port, directly expelling gas from the cabinet to prevent a sudden increase in internal pressure. When cleaning residue, this port can also serve as a slag discharge outlet, allowing accumulated residue in the storage space to fall off by gravity when the opening faces outwards, facilitating cleaning operations.

[0018] Preferably, both the arc-shaped plate and the circular piece are coated with an arc-resistant insulating coating.

[0019] In the above scheme, the arc-resistant insulating coating forms a protective layer on the surface of the arc plate and the disc. When the arc fault causes high-temperature ablation, the coating can resist the burning and electrical erosion of the arc temperature, extend the service life of the arc plate and the disc under extreme working conditions, prevent the arc guiding channel from failing due to the melting of the metal surface or the decrease in insulation performance, and ensure that the arc guiding mechanism can still maintain the current guiding and pressure relief function under fault conditions.

[0020] Preferably, the flexible tape is a composite insulating tape with glass fiber base cloth coated with flame-retardant silicone rubber on both sides.

[0021] In the above solution, the fiberglass base fabric provides sufficient tensile strength and dimensional stability, allowing the flexible tape to remain flat during repeated winding and unwinding. The double-sided flame-retardant silicone rubber coating gives the flexible tape insulation and flame-retardant properties, forming an insulating barrier between the live parts in adjacent unmaintained functional units and the outside world. At the same time, the flexibility of the silicone rubber allows the flexible tape to adapt to the bending and winding of the winding shaft, meeting the needs of frequent winding and unwinding operations.

[0022] Preferably, the cabinet frame is divided into a busbar compartment, a component compartment, an outgoing cable compartment, and an auxiliary parts compartment. The cabinet frame is equipped with drawer units, which are assembled in the component compartment. The busbar compartment, component compartment, outgoing cable compartment, and auxiliary parts compartment are separated from each other by steel plates or insulating plates to form independent compartments. The maintenance window of the maintenance and protection mechanism corresponds to the rear side of the designated independent compartment or drawer unit.

[0023] In the above scheme, the modular hole splicing structure of the C-shaped frame allows the cabinet frame to flexibly adjust the installation height and spacing of each compartment according to the actual number of circuits, adapting to the needs of different power distribution capacities. Each functional compartment is isolated from each other by steel plates or insulating plates, confining live parts to their own independent spaces. Combined with the fixed-point window opening function of the rear maintenance protection mechanism, only the target compartment is exposed during maintenance, while the other compartments remain closed and isolated, further reducing the risk of accidental cross-contamination. The multiple interlocking protection mechanism works in conjunction with the drawer unit to ensure that the drawer cannot be accidentally pulled out when in the running position, improving operational safety.

[0024] Preferably, the component is equipped with a circuit breaker, a control handle, and an instrument unit. The instrument unit is equipped with an instrument unit door interlocking structure. The circuit breaker is connected to the outer door of the switch cabinet via a door coupling mechanism to prevent the outer door from opening under load. The control handle is equipped with a locking structure. The drawer unit integrates a mechanical interlocking device to achieve interlocking and limiting of the drawer in three working positions: connection, testing, and separation. This, together with the maintenance and protection mechanism on the rear side of the cabinet frame, forms a double safety protection system.

[0025] In the above scheme, the interlocking structure of the instrument unit door and the interlocking of the door coupling mechanism together form a dual electrical and mechanical protection, preventing the outer door from opening when the circuit breaker is under load, ensuring operational safety; the locking structure of the control handle supports multi-person locking and tagging management, with multiple people locking themselves during maintenance to prevent single-person misoperation from endangering others; the mechanical interlocking device of the drawer unit ensures that the drawer can only be pulled out or inserted when it is in the separated position, and works in conjunction with the fixed-point window opening function of the rear maintenance protection mechanism to form a coordinated front and rear overall safety protection system, improving the safety level of maintenance operations.

[0026] Compared with the prior art, the present invention has the following beneficial effects: 1. Compared to traditional low-voltage switchgear with an integrated rear door, this invention utilizes a maintenance and protection mechanism consisting of a retractor, a servo motor, and a flexible belt with an inspection port. During normal operation, the flexible belt covers the rear opening of the cabinet, isolating the live parts in adjacent unmaintained functional units. The servo motor's self-locking mechanism maintains stable position, and the annular baffle provides lateral limiting, achieving normal protection. During maintenance, the retractor drives the flexible belt to move horizontally, ensuring that the inspection port is aligned with the compartment or drawer unit to be inspected, while the remaining areas remain sealed and isolated. This avoids the defect of exposing non-maintained areas when the entire rear door is opened, reducing the range of live exposure and minimizing the risk of accidental contact by maintenance personnel.

[0027] 2. Compared to conventional cabinet structures that directly release internal electric arcs, this invention utilizes a multi-layered arc-shaped plate arc-guiding mechanism. When an internal short-circuit arc fault occurs, the flexible belt blocks the forward diffusion of airflow and residue. Laterally overflowing airflow enters the guiding mechanism through the side plate openings and is guided upwards along the arc surface of the arc-shaped plate, directionally releasing it from the upper port of the storage space to the outside of the cabinet. This helps reduce the risk of structural damage caused by a sudden increase in internal pressure. Simultaneously, solid residues such as molten metal slag and conductive carbon slag carried by the airflow are partially retained in the storage space due to the obstruction of the arc surface and gravity, preventing residues from splashing everywhere and contaminating internal components or injuring external personnel, thus improving the safety level of equipment and personnel in fault scenarios.

[0028] 3. Compared to conventional cabinet heat dissipation solutions that require additional ventilation holes, this invention uses multi-layered storage space as parallel heat dissipation channels. By utilizing the curved surface guide and chimney effect, a natural convection heat dissipation path is formed, which can remove some of the heat inside the cabinet and reduce the operating temperature rise. At the same time, the exposed area of ​​the upper port of the storage space can be flexibly adjusted by controlling the rotation angle of the curved plate, thereby adjusting the flow capacity of the heat dissipation channel to adapt to the heat dissipation needs of the cabinet under different loads and ambient temperatures. When the switch cabinet is not in operation, the curved plate can be controlled to block the side panel openings, cut off the heat dissipation channel, and prevent external dust from entering the cabinet, improving the dustproof effect in non-operating conditions and achieving multi-condition adaptability.

[0029] 4. Compared to cleaning methods that require manual insertion into the cabinet to adjust the arc guiding structure, this invention achieves linkage control between the maintenance and protection mechanism and the arc guiding mechanism through the magnetic attraction between the flexible magnet built into the flexible belt and the electromagnet of the movable rod. When cleaning residue, the lifting and lowering of the flexible belt can synchronously drive the arc plate to flip, so that the opening of the storage space faces the outside of the cabinet. The residue inside can fall off by gravity, avoiding contact with residual live parts, thus improving the safety and convenience of cleaning operations. Moreover, there is no need to configure a separate drive source for the arc guiding mechanism, which simplifies the overall structure and control costs. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the structure of the present invention. Figure 2 ; Figure 3 This is a rear view diagram of the present invention; Figure 4 This is a schematic diagram of the rear of the switchgear in a non-maintenance state. Figure 5 for Figure 4 Schematic diagram of the internal structure of the middle cabinet frame; Figure 6 This is an enlarged schematic diagram of a portion of the flexible strip structure in this invention. Figure 1 ; Figure 7 This is a magnified schematic diagram of a portion of the flexible strip structure in this invention. Figure 2 ; Figure 8 This is an exploded view of the side plate and the arc-shaped plate in this invention; Figure 9 This is an enlarged schematic diagram of a portion of the structure at the side plate in this invention; Figure 10 This is an exploded view of the movable rod, guide rod, and arc-shaped plate in this invention; Figure 11 for Figure 10 Enlarged diagram of point A in the diagram; Figure 12 This is an enlarged cross-sectional view of a portion of the structure at the arc-shaped plate in this invention.

[0031] In the diagram: 1. Cabinet frame; 2. Side panel; 3. Through opening; 101. Retracting shaft; 102. Circular baffle; 103. Flexible belt; 104. Servo motor; 105. Controller; 106. Inspection port; 107. Flexible magnet; 108. Electromagnet; 201. Curved plate; 202. Circular piece; 203. Connecting shaft; 204. Storage space; 205. Guide rod; 206. Movable rod; 207. Slide groove; 208. Base plate; 209. Anti-slip texture; 210. Drive bar. Detailed Implementation

[0032] 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. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0033] Reference Figures 1 to 12 The present invention provides a modular small withdrawable low-voltage switchgear, including a cabinet frame 1, which is assembled from multiple C-shaped skeletons with spaced modular holes. A detachable top cover is provided on the top of the cabinet frame 1. Side plates 2 are fixedly installed on both rear ends of the cabinet frame 1. The rear side of the cabinet frame 1 has an open structure, and the opening is located between the two side plates 2.

[0034] like Figures 1 to 3 As shown, the cabinet frame 1 is divided into a busbar compartment, a component compartment, an outgoing cable compartment, and an auxiliary compartment. The component compartment can be equipped with multiple drawer unit installation positions according to the circuit configuration. All drawer units belong to the component compartment as an independent functional compartment. The vertical movement stroke of the flexible belt 103 covers the total height of all compartments and drawer layers. The access port 106 is a fixed-size opening. The vertical size is designed according to the maximum maintenance requirements of a single compartment, which can completely cover the rear maintenance area of ​​a single compartment or drawer layer. The vertical center position of each compartment and drawer layer corresponds one-to-one with the movement point of the access port 106. The access port 106 can be aligned with the rear opening of any compartment or drawer unit to realize a fixed-point opening for maintenance. The busbar compartment, component compartment, outgoing cable compartment, and auxiliary parts compartment are separated from each other by steel plates or insulating plates, forming independent compartments. The cabinet frame 1 is equipped with drawer units, which are mounted in the component compartment. Each drawer unit has a multi-interlock protection mechanism, forming a dual safety protection system with the rear maintenance protection mechanism. The component compartment is equipped with circuit breakers, control handles, and instrument units. The control handles and switch handles are marked with corresponding gear positions. The instrument units are equipped with a door interlock structure, and a door coupling mechanism is installed between the circuit breaker and the switch cabinet's outer door. The lock is used to prevent the outer door from opening under load. The control handle is equipped with a locking structure that can simultaneously attach three padlocks. During maintenance, multiple people can lock and tag the door for management, matching the safe operation procedure of fixed-point maintenance at the rear. The drawer unit has visual labels printed on the drawer panel indicating three working positions: connection, test, and separation. The drawer unit integrates a mechanical interlocking device to achieve interlocking and limiting of different working positions of the drawer. Before maintenance, the drawer is switched to the separation position, and then the work is carried out through the rear maintenance port 106, further avoiding the risk of live maintenance.

[0035] like Figure 2 , Figure 3 , Figure 5 , Figure 6 and Figure 7 As shown, a maintenance and protection mechanism is installed inside the rear opening of the cabinet frame 1. This mechanism includes retractable shafts 101 spaced vertically. The ends of the retractable shafts 101 are rotatably mounted on the side plate 2. Annular baffles 102 are fixedly installed at both ends of the retractable shafts 101. A flexible belt 103 is provided between the two retractable shafts 101. The end of the flexible belt 103 is fixedly connected to and wound onto the retractable shafts 101. The annular baffles 102 on both sides laterally limit the movement of the flexible belt 103. The two side edges are fitted with the inner side of the side plate 2 with a small gap, forming an effective protective partition under normal conditions; two servo motors 104 are fixedly installed on the side plate 2, and the output shafts of the servo motors 104 are fixedly connected to the winding shaft 101 respectively. A controller 105 is fixedly installed on the side plate 2, and the controller 105 is used to control the operation of the two servo motors 104. An inspection port 106 is opened on the flexible belt 103, and the inspection port 106 passes through the flexible belt 103. The cabinet frame 1 is in an open state through the inspection port 106.

[0036] In non-maintenance mode, the maintenance protection mechanism is used to block the opening on the rear side of the cabinet frame 1 to reduce the area of ​​the exposed electrical structure inside the cabinet frame 1; in maintenance mode, the maintenance protection mechanism opens the maintenance window on the rear side of the cabinet frame 1 according to the maintenance location.

[0037] like Figure 2 , Figure 8 , Figure 9 , Figure 10 and Figure 11As shown, a through-hole 3 is provided on the side plate 2 located on one side, and an arc guiding mechanism is installed in the through-hole 3. The arc guiding mechanism includes multiple arc-shaped plates 201 located in the through-hole 3. The multiple arc-shaped plates 201 are arranged at equal intervals. Circular pieces 202 are fixedly installed on both sides of the arc-shaped plates 201. The arc-shaped plates 201 and the circular pieces 202 on both sides form a storage space 204. A connecting shaft 203 is fixedly installed on each of the circular pieces 202. The end of the connecting shaft 203 is rotatably installed on the side plate 2. The upper end of the storage space 204 is exposed outside the cabinet frame 1. The surfaces of the arc-shaped plates 201 and the circular pieces 202 are coated with an arc-resistant insulating coating to enhance the structural ablation resistance under high-temperature arc conditions and extend the effective arc guiding time under fault scenarios.

[0038] When an internal electric arc occurs in the cabinet frame 1, the heat is released through the electric arc guiding mechanism. In the slag removal state after the fault has been isolated, the maintenance and protection mechanism can controllably switch the working angle of the electric arc guiding mechanism, so that the electric arc guiding mechanism rotates to the slag discharge position to discharge the residue generated after the electric arc.

[0039] Reference Figure 8 , Figure 10 , Figure 11 and Figure 12 The arc guiding mechanism also includes an adjustment component, which includes a guide rod 205. The guide rod 205 is set inside the cabinet frame 1 and fixedly installed on the side plate 2. A movable rod 206 is provided inside the cabinet frame 1. A sliding groove 207 is opened on the movable rod 206. One end of the guide rod 205 extends into the sliding groove 207. The movable rod 206 is slidably installed on the guide rod 205. A base plate 208 is fixedly installed at the bottom of the guide rod 205. The base plate 208 is used to limit the lower part of the movable rod 206. The outer surface of the circular piece 202 is distributed with anti-slip textures 209. A drive bar 210 is fixedly installed on the movable rod 206. The surface of the drive bar 210 is distributed with anti-slip particles. The drive bar 210 abuts against the anti-slip textures 209 on the multiple circular pieces 202 and forms a friction transmission engagement.

[0040] Reference Figure 7 and Figure 9The maintenance and protection mechanism also includes a flexible magnet 107, which is embedded in the flexible strip 103 and distributed along the length of the flexible strip 103. The flexible magnet 107 is positioned towards the movable rod 206. Multiple electromagnets 108 are fixedly installed on the movable rod 206, which are distributed vertically and horizontally at equal intervals. When the electromagnets 108 are energized, they are in contact with the flexible magnet 107. The electromagnets 108 are controlled by the controller 105. In the slag removal state, the maintenance and protection mechanism drives the movable rod 206 to move through the attraction between the flexible magnet 107 and the electromagnets 108, and controls the switching of the working angle of the arc guiding mechanism to the slag discharge position. The flexible strip 103 is preferably a composite insulating strip material with glass fiber base cloth coated with flame-retardant silicone rubber on both sides. The glass fiber base cloth ensures structural rigidity and temperature resistance, while the silicone rubber coating provides insulation, which is suitable for the operating environment of the switchgear and meets the requirements of repeated winding.

[0041] Working principle of the invention: Normal operating (non-maintenance) status: The controller 105 controls two servo motors 104 to operate, and the two servo motors 104 perform synchronous differential control of speed and position, driving the upper and lower take-up shafts 101 to rotate, thereby adjusting the position of the flexible belt 103 and maintaining the tension of the flexible belt 103 when moving and stopping, so that the solid surface of the flexible belt 103 covers the rear opening of the cabinet frame 1. At this time, the part of the flexible belt 103 located at the maintenance port 106 is wound into the upper take-up shaft 101. At this time, the live parts in the adjacent unmaintained functional units inside the cabinet are isolated by the flexible belt 103 and will not be directly exposed to the outside, achieving normal safety protection. After the position of the flexible belt 103 is adjusted, both servo motors 104 are in a self-locking state to maintain the position stability of the flexible belt 103. The annular baffles 102 at both ends of the take-up shaft 101 limit the lateral movement of the flexible belt 103.

[0042] At the same time, the arc guiding mechanism is in standby arc guiding state, and the storage space 204 formed by the arc plates 201 of each layer and the circular plates 202 on both sides faces the inside of the cabinet. The upper port of the storage space 204 is exposed to the outside of the cabinet frame 1. When the cabinet is running normally, the arc guiding mechanism serves as a protective structure on the side of the cabinet.

[0043] On the other hand, the upper port of the storage space 204 serves as a heat dissipation channel for the switch cabinet, and the curved surface of the arc plate 201 forms a guide air duct, guiding the flow of hot air and exhausting it from the upper port of the storage space 204 exposed to the outside of the cabinet, forming a natural convection heat dissipation path. Combined with the air intake structure at the bottom of the cabinet, the chimney effect is used to help remove the heat inside the cabinet. The multi-layered storage space 204 forms multiple sets of parallel heat dissipation channels, achieving passive auxiliary heat dissipation without opening additional heat dissipation holes in the cabinet or reducing the side protection performance of the cabinet, which is conducive to reducing the internal operating temperature rise of the cabinet. The shielding structure of the arc plate 201 can prevent external foreign objects from directly entering the cabinet, taking into account both protection and heat dissipation functions.

[0044] Maintenance status: When a specific compartment inside the cabinet needs maintenance, the operator sets the maintenance position via controller 105. Controller 105 then controls two servo motors 104 to operate synchronously: the upper winding shaft 101 releases the flexible belt 103, and the lower winding shaft 101 winds up the flexible belt 103. Under the tension maintained by the controller, the two motors work together to drive the flexible belt 103 downwards, moving the maintenance port 106 on the flexible belt 103 to the corresponding position in the compartment to be maintained, aligning it with the rear opening of the corresponding floor busbar compartment, component compartment, or outgoing cable compartment. At this time, only the rear of the cabinet corresponding to the maintenance port 106 is open, while the remaining areas are still blocked and isolated by the flexible belt 103. This avoids the problem of needing to open the entire rear door and expose all the live parts in adjacent unmaintained functional units, as is common in traditional structures. It also reduces the range of live parts exposed during maintenance, lowering the safety risk of accidental contact.

[0045] Internal arc fault discharge and cleanup: When a short-circuit arc fault occurs inside the cabinet, the gas generated instantaneously carries solid residues such as molten metal slag and conductive carbon slag and spreads to the surroundings. When an internal arc occurs in the cabinet frame 1, the heat is released through the arc guiding mechanism. The flexible belt 103 blocks the forward-spreading airflow and residues. The laterally spreading airflow and residues enter the arc guiding mechanism through the through-hole 3 on the side plate 2.

[0046] The curved surfaces of each layer of arc-shaped plates 201 form upward flow channels, guiding the airflow upward along the curved surfaces, and finally directionally releasing it from the upper port of the storage space 204 to the outside of the cabinet, realizing the lateral discharge and upward pressure relief of the electric arc energy, and avoiding structural damage caused by a sudden increase in internal pressure. Meanwhile, solid residues such as molten metal slag and carbon slag carried by the airflow are blocked by the arc-shaped plates 201 and gravity, and remain inside the storage space 204, preventing the residues from splashing everywhere with the airflow, contaminating the internal components of the cabinet or injuring external personnel.

[0047] After the arc fault is cleared, the residue accumulated in the storage space 204 needs to be cleaned. At this time, the maintenance and protection mechanism and the arc guiding mechanism are linked together to automatically adjust the angle of the arc plate 201. Under the slag cleaning state where the main circuit fault has been isolated and the power is safely cut off, and the control circuit is kept powered, the maintenance and protection mechanism can controllably switch the working angle of the arc guiding mechanism to rotate the arc guiding mechanism to the slag discharge position to discharge the residue generated after the arc. The residue cleaning mode is started by the controller 105 after receiving external instructions and according to the preset timing. First, the self-locking state of the two servo motors 104 is released, and then the electromagnets are energized and the flexible belt moves upward in sequence. After the two servo motors 104 are released from the self-locking mode, the flexible belt 103 is in a relaxed state. Multiple electromagnets 108 are energized to generate magnetic force and are tightly attracted to the flexible magnets 107 on the flexible belt 103. At the same time, the flexible belt 103 is bent and deformed. Since the main circuit has been de-energized and isolated at this time, the local yielding deformation of the flexible belt 103 will not introduce the risk of external electric shock.

[0048] The controller 105 then controls two servo motors 104 to move the flexible belt 103 upward. Within a preset clearance, the flexible belt 103 drives the movable rod 206 to move upward synchronously through magnetic attraction. The drive bar 210 on the movable rod 206 moves upward synchronously. The anti-slip particles on the surface of the drive bar 210 generate static friction with the anti-slip texture 209 on the outer surface of the disc 202, causing all the discs 202 to rotate synchronously around the connecting shaft 203. This, in turn, causes all the curved plates 201 to rotate synchronously until the opening of the storage space 204 is exposed to the outside of the cabinet. The bottom plate 208 at the bottom of the guide rod 205 limits the lower limit position of the movable rod 206 to prevent the movable rod 206 from dislodging from the guide rod 205 structure.

[0049] With the opening of the storage space 204 facing outwards, the accumulated molten slag and carbon residue can fall off under gravity, making it easy for staff to clean directly without having to reach inside the cabinet to manually adjust the curved plate 201. This avoids contact with residual live parts and improves the safety of the cleaning operation. After cleaning, the electromagnets 108 are de-energized, which then drives the flexible belt 103 to reset. The movable rod 206 slides downwards and resets under its own weight, thereby resetting the storage space 204 and restoring the equipment to normal operation.

[0050] Furthermore, when the electromagnet 108 is energized, the flexible belt 103 drives the circular plate 202 and the arc plate 201 to rotate synchronously. By controlling the rotation angle of the arc plate 201, the size of the upper port of the storage space 204 exposed outside the cabinet frame 1 is adjusted, that is, the flow capacity of the heat dissipation channel is adjusted to adapt to the heat dissipation needs of the cabinet under different load power and different ambient temperatures. On the other hand, when the switch cabinet is not in operation, the arc plate 201 blocks the through-hole 3 on the side plate 2 and the storage space 204 is located inside the cabinet frame 1. At this time, the heat dissipation channel is closed, effectively preventing external dust from entering the cabinet from the upper port of the storage space 204, thus improving the dustproof effect in the non-operational state.

[0051] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

Claims

1. A modular, small withdrawable low-voltage switchgear, characterized in that, The cabinet includes a cabinet frame (1), with side panels (2) fixedly installed on both rear ends of the cabinet frame (1). The rear side of the cabinet frame (1) has an opening structure, and the opening is located between the two side panels (2). A maintenance protection mechanism is installed in the opening on the rear side of the cabinet frame (1). In the non-maintenance state, the maintenance protection mechanism is used to block the opening on the rear side of the cabinet frame (1) to reduce the area of ​​the electrical structure inside the cabinet frame (1) exposed. In the maintenance state, the maintenance protection mechanism opens the maintenance window on the rear side of the cabinet frame (1) according to the maintenance position. A through hole (3) is opened on the side panel (2) on one side. An arc guiding mechanism is installed in the through hole (3). When the cabinet frame (1) generates an internal arc, the heat is released through the arc guiding mechanism.

2. The modular miniature withdrawable low-voltage switchgear according to claim 1, characterized in that, The maintenance and protection mechanism includes a winding shaft (101) spaced vertically. The ends of the winding shaft (101) are rotatably mounted on a side plate (2). Both ends of the winding shaft (101) are fixedly fitted with annular baffles (102). A flexible belt (103) is provided between the two winding shafts (101). The ends of the flexible belt (103) are fixedly connected to the winding shafts (101) and wound onto them. The annular baffles (102) on both sides laterally limit the movement of the flexible belt (103). Two servo motors (104) are fixedly installed on the side plate (2). The output shafts of the servo motors (104) are fixedly connected to the winding shaft (101). A controller (105) is fixedly installed on the side plate (2). The controller (105) is used to control the operation of the two servo motors (104). An inspection port (106) is provided on the flexible belt (103). The inspection port (106) passes through the flexible belt (103). The cabinet frame (1) is in an open state through the inspection port (106).

3. A modular miniature withdrawable low-voltage switchgear according to claim 2, characterized in that, The arc guiding mechanism includes multiple arc-shaped plates (201) located in the opening (3). The multiple arc-shaped plates (201) are arranged at equal intervals. Circular pieces (202) are fixedly installed on both sides of the arc-shaped plates (201). The arc-shaped plates (201) and the circular pieces (202) on both sides form a storage space (204). A connecting shaft (203) is fixedly installed on each of the circular pieces (202). The end of the connecting shaft (203) is rotatably installed on the side plate (2).

4. A modular miniature withdrawable low-voltage switchgear according to claim 3, characterized in that, The arc guiding mechanism further includes an adjusting assembly, which includes a guide rod (205). The guide rod (205) is disposed within the cabinet frame (1) and fixedly mounted on the side plate (2). A movable rod (206) is provided within the cabinet frame (1). A groove (207) is provided on the movable rod (206). One end of the guide rod (205) extends into the groove (207). The movable rod (206) is slidably mounted on the guide rod (205). A base plate (208) is fixedly installed at the bottom of the guide rod (205). The base plate (208) is used to limit the movement of the rod (206) below. Anti-slip textures (209) are distributed on the outer surface of the disc (202). A drive bar (210) is fixedly installed on the rod (206). Anti-slip particles are distributed on the surface of the drive bar (210). The drive bar (210) abuts against the anti-slip textures (209) on the discs (202) and forms a friction transmission engagement.

5. A modular miniature withdrawable low-voltage switchgear according to claim 4, characterized in that, The maintenance and protection mechanism also includes a flexible magnet (107), which is embedded in the flexible strip (103) and distributed along the length of the flexible strip (103). The flexible magnet (107) is positioned facing the movable rod (206). Multiple electromagnets (108) are fixedly installed on the movable rod (206) and are distributed vertically and vertically at equal intervals. When the electromagnets (108) are energized, they are in contact with the flexible magnet (107). The electromagnets (108) are controlled by the controller (105). In the slag removal state, the maintenance and protection mechanism drives the movable rod (206) to move through the attraction between the flexible magnet (107) and the electromagnets (108), and controls the switching of the working angle of the arc guiding mechanism to the slag discharge position.

6. A modular miniature withdrawable low-voltage switchgear according to claim 3, characterized in that, The upper port of the storage space (204) is exposed outside the cabinet frame (1).

7. A modular miniature withdrawable low-voltage switchgear according to claim 3, characterized in that, Both the arc plate (201) and the circular piece (202) are coated with an arc-resistant insulating coating.

8. A modular miniature withdrawable low-voltage switchgear according to claim 2, characterized in that, The flexible tape (103) is a composite insulating tape with glass fiber base cloth coated with flame-retardant silicone rubber on both sides.

9. A modular miniature withdrawable low-voltage switchgear according to claim 1, characterized in that, The cabinet frame (1) is divided into a busbar compartment, a component compartment, an outgoing cable compartment, and an auxiliary compartment. The cabinet frame (1) is equipped with a drawer unit, which is installed in the component compartment. The busbar compartment, component compartment, outgoing cable compartment, and auxiliary compartment are separated from each other by steel plates or insulating plates to form independent compartments. The maintenance window of the maintenance and protection mechanism corresponds to the rear side of the designated independent compartment or drawer unit.

10. A modular miniature withdrawable low-voltage switchgear according to claim 9, characterized in that, The component is equipped with a circuit breaker, a control handle and an instrument unit. The instrument unit is equipped with an instrument unit door interlocking structure. The circuit breaker and the outer door of the switch cabinet are equipped with a door coupling mechanism for interlocking, which is used to block the opening action of the outer door under load. The control handle is equipped with a locking structure. The drawer unit integrates a mechanical interlocking device, which realizes the interlocking limit of the three working positions of drawer connection, test and separation through mechanical interlocking, and forms a double safety protection front and rear with the maintenance protection mechanism on the rear side of the cabinet frame (1).

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