Low-voltage switchgear and heat dissipation control method thereof

Abstract

This invention discloses a low-voltage switchgear and its heat dissipation control method. The switchgear includes a cabinet, a top cover, and a ventilation box located at the top of the cabinet. The ventilation box contains multiple independent ventilation structures, each including a wind chamber and a zigzag air duct. The air duct is composed of multiple ventilation sections connected at angles of 100-160°. Ventilation zones with ventilation holes are provided around the perimeter of the ventilation box. A ventilation box with a fan is located at the bottom of the cabinet, and air outlets are provided around the top cover. A movable baffle with micro-perforations is provided at the connection between the wind chamber and the air duct, which is normally closed by its own weight or a torsion spring. The control method is as follows: when the temperature is below a threshold, natural convection is used for heat dissipation; when the temperature exceeds the threshold, the wind direction is determined by a wind pressure sensor, and the fan on the leeward side is activated first, automatically opening the movable baffle using the pressure difference to achieve efficient forced air cooling. This invention combines natural heat dissipation with intelligent forced air cooling, along with a dust-proof settling air duct and an adaptive baffle, significantly improving the heat dissipation efficiency, dust resistance, and operational reliability of the switchgear.

Description

Technical Field

[0001] This invention belongs to the technical field of electrical equipment technology, specifically relating to low-voltage switchgear and its heat dissipation control method. Background Technology

[0002] Low-voltage switchgear is an indispensable power distribution device in power systems, integrating a large number of circuit breakers, contactors, relays, and electronic components. These components generate a lot of heat during operation. If the heat cannot be dissipated in time, the temperature inside the cabinet will rise, directly affecting the service life and operational reliability of the electrical equipment, and may even cause safety accidents.

[0003] Traditional low-voltage switchgear typically uses louvers or ventilation holes on the side walls or top of the cabinet for natural ventilation and heat dissipation. However, this method has significant drawbacks: firstly, the heat dissipation efficiency is low, making it difficult to cope with heat accumulation during high-load operation; secondly, the ventilation holes lead directly into the cabinet interior, and in areas with high winds and sandstorms, external dust can easily enter the cabinet with the airflow, adhere to electrical components, and lead to decreased insulation performance, poor contact, or short-circuit faults.

[0004] To address these issues, existing technologies include adding independent air ducts to the cabinet or using fans for forced cooling. However, most solutions are structurally complex, have poorly designed air ducts, fail to effectively utilize natural wind power, and lack the ability to intelligently adjust based on external environmental factors (such as wind direction and temperature). Furthermore, while some solutions consider dust prevention, they typically rely on simply adding filters, which not only increases air resistance but also requires frequent manual cleaning and maintenance. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a low-voltage switchgear, including a cabinet body, a top cover at the top of the cabinet body, a ventilation box at the top of the cabinet body, a plurality of ventilation structures inside the ventilation box, the ventilation structures including air chambers and air ducts, a plurality of ventilation zones around the ventilation box, each ventilation zone corresponding to a ventilation structure, a plurality of ventilation holes within the ventilation zones, the ventilation holes communicating with the air chambers in the corresponding ventilation structures, the air duct being composed of a plurality of ventilation segments connected sequentially, adjacent ventilation segments forming an angle of 100-160°, one end of the air duct communicating with the corresponding air chamber, and the other end communicating with the bottom of the cabinet body, and a plurality of air outlets around the top cover, the air outlets communicating with the top of the cabinet body.

[0006] The lower end of the ventilation zone is provided with a sand discharge port, which is connected to the lower end of the ventilation chamber. The sand discharge port is covered with a cover plate, which is detachably connected to the ventilation box.

[0007] The air chamber is surrounded by several panels, with the panel at the bottom of the air chamber serving as the base plate. The base plate is inclined and its lower end is close to the sand discharge port.

[0008] The lower part of the cabinet is provided with several ventilation boxes, each with a ventilation opening. A fan is installed inside the ventilation opening, and the air duct connects to the inside of the ventilation box.

[0009] The ventilation box has four ventilation structures and four ventilation zones (distributed in, for example, front, back, left, and right directions). The four ventilation zones have different orientations, and there are four ventilation boxes inside the cabinet.

[0010] The connection between the air duct and the air chamber is set as a communication port, which is set downward. A movable baffle is provided at the communication port. A rotating shaft is installed on one side of the communication port, and an upper limit plate and a lower limit plate are provided on the other side. One side of the movable baffle is set as a hinge part, and the other side is set as a movable part. The hinge part is connected to the rotating shaft in the air chamber through a bearing. The movable part moves between the upper limit plate and the lower limit plate. When the movable part contacts the upper limit plate, the communication port is in an open state. When the movable part contacts the lower limit plate, the communication port is in a closed state. The movable part is kept in contact with the lower limit plate by the elastic force of the torsion spring installed on the rotating shaft or by the weight of the movable baffle. The movable baffle is provided with several micro-holes.

[0011] A temperature sensor is installed inside the cabinet, and a wind pressure sensor is installed in each of the ventilation zones. The orientation of the wind pressure sensor is consistent with the orientation of the ventilation hole in the corresponding ventilation zone.

[0012] Methods for controlling heat dissipation in low-voltage switchgear include: Natural heat dissipation mode: When the temperature sensor inside the cabinet detects that the temperature inside the cabinet is lower than the preset start threshold T1, all fans remain off. Outside airflow enters the air chamber through the ventilation holes in the ventilation area, passes through the micropores on the movable baffle, flows into the air duct, and then enters the cabinet interior through the ventilation openings of the ventilation box. The hot air inside the cabinet rises naturally due to its reduced density and is eventually exhausted through the air vents around the top cover, completing the natural convection heat dissipation cycle. Intelligent Forced Cooling Mode: When the temperature sensor detects that the temperature inside the cabinet is higher than the preset start threshold T1, the control system activates the forced cooling logic: The control system reads the wind pressure sensor data installed in each ventilation zone, analyzes and determines the current wind direction; based on the wind direction determination result, the control system prioritizes starting the fans in one or more ventilation boxes located on the leeward side; at the same time, the fans on the windward or side wind sides are kept off or at low speed; after the fans start, a negative pressure is formed in the corresponding air duct, causing a pressure difference on both sides of the movable baffle. This pressure difference overcomes the weight of the movable baffle and / or the elastic force of the torsion spring, driving the movable baffle to rotate around the pivot until its movable part contacts the upper limit plate, so that the connection port is fully opened; after the connection port is opened, a large amount of outside air is forcibly drawn into the cabinet through the ventilation holes, air chamber, connection port, and air duct under the suction of the fan, flows through the heating elements inside the cabinet, and is discharged from the air outlet of the top cover carrying heat, achieving efficient forced cooling; Heat dissipation maintenance and deactivation: During forced heat dissipation mode operation, the control system continuously monitors the temperature inside the cabinet; when the temperature inside the cabinet drops below the preset stop threshold T2, where T2 < T1, the control system controls the fan to stop operating; after the fan stops, the negative pressure in the air duct disappears, the movable baffle resets under its own weight and / or torsion spring action, its movable part re-contacts the lower limit plate, the connection port returns to the closed state, and the system automatically switches back to natural heat dissipation mode.

[0013] The beneficial effects of this invention are: This invention deeply integrates natural convection and forced air cooling. Basic heat dissipation is achieved through the "chimney effect" formed by the air vents on the top cover; when the temperature exceeds the standard, the system intelligently judges the wind direction based on the wind pressure sensor and prioritizes the activation of the fan on the leeward side to avoid fighting against the natural wind and prevent sand and dust from directly entering the cabinet. The forced suction and natural wind pressure work together to significantly improve heat dissipation efficiency, reduce the impact of sand and dust on the electrical components inside the cabinet, and improve heat dissipation efficiency. The air duct adopts a zigzag structure, which uses the airflow bend to allow sand and dust to settle naturally at the bottom of the air chamber. Combined with the inclined bottom plate and sand discharge port, it can be cleaned regularly. At the same time, the movable baffle is kept closed by its own weight or torsion spring when the fan is off, allowing only micropores to pass through. In the non-working state, it effectively blocks sand and dust from entering, greatly reducing insulation failures caused by dust accumulation. Based on dual sensing of temperature and wind direction, the system automatically switches between natural and forced modes to avoid inefficient fan operation and reduce energy consumption. The purely mechanical movable baffle structure can adaptively open and close according to pressure difference without electronic control, simplifying the control logic and improving the long-term operational reliability of the system in harsh environments. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2This is a schematic diagram of the cross-sectional structure of the present invention. Detailed Implementation

[0015] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0017] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0018] like Figure 1-2 As shown, the low-voltage switchgear includes a cabinet body 1 and a top cover 2 disposed on the top of the cabinet body 1. A ventilation box 3 is fixedly installed on the upper end of the cabinet body 1.

[0019] The interior of the ventilation box 3 is divided into four independent ventilation structures by partitions, corresponding to the front, rear, left, and right directions of the cabinet. Each ventilation structure includes an air chamber 4 and an air duct 5. On the outer walls of the ventilation box 3, in the area corresponding to each ventilation structure, there is a ventilation zone 6, with multiple elongated or circular ventilation holes 61 for the entry of outside air. The ventilation holes 61 are directly connected to the corresponding air chamber 4.

[0020] The air duct 5 is composed of multiple inclined ventilation sections 51 connected end to end, forming an overall "Z" shape or zigzag shape, with the included angle between adjacent ventilation sections preferably being 135°. The upper inlet of the air duct 5 is connected to the air chamber 4, and the lower outlet is connected to the internal cavity of the ventilation box 7 located at the lower end of the cabinet 1. The ventilation box 7 has a ventilation opening 71 on the side facing the inside of the cabinet, and an axial flow fan 72 is installed inside the ventilation opening 71.

[0021] A movable baffle 8 is provided at the connection port 41 between the air chamber 4 and the air duct 5. The connection port 41 is located at the bottom of the air chamber 4 and faces downward. A rotating shaft 81 is fixed to one side of the connection port 41, and an upper limit plate 82 and a lower limit plate 83 are fixed to the other side. One end of the movable baffle 8 is a hinge part 84, which is sleeved on the rotating shaft 81 and can rotate around it; the other end is a movable part 85, which is movably clamped between the upper limit plate 82 and the lower limit plate 83. A torsion spring (not shown in the figure) is sleeved on the rotating shaft 81. The torque of the torsion spring causes the movable part 85 of the movable baffle 8 to always press against the lower limit plate 83 when no external force is applied, thereby closing the connection port 41. A plurality of micro-holes 86 are evenly distributed on the surface of the movable baffle 8. When the connection port is closed, the micro-holes 86 still allow a small amount of air to flow.

[0022] The bottom plate 42 of the ventilation chamber 4 is inclined, with its lowest point located at the sand discharge port 9. The sand discharge port 9 is located below the ventilation zone 6 and is normally closed by a removable cover plate 91.

[0023] The top cover 2 has multiple downward-facing air vents 21 around its perimeter.

[0024] A temperature sensor 10 is installed inside the cabinet 1 to monitor the temperature inside the cabinet. A wind pressure sensor 11 is installed on the inner or outer side of each ventilation zone 6. The pressure-sensing surface of the wind pressure sensor 11 is aligned with the orientation of the ventilation hole 61 to detect the wind pressure in that direction.

[0025] Based on the above structure, the heat dissipation control method of this embodiment is as follows: The system presets a start-up temperature threshold T1 (e.g., 45℃) and a stop-down temperature threshold T2 (e.g., 40℃).

[0026] When the temperature sensor 10 detects that the cabinet temperature T < T1, the system is in natural heat dissipation mode. At this time, the fan 72 does not work. Due to the negative pressure generated by the rising hot air inside the cabinet, outside air enters the air chamber 4 through the ventilation holes 61 in all directions. Since the movable baffle 8 is in the closed state, the air can only slowly enter the air duct 5 through the micropores 86 on it, and then enter the cabinet 1 through the ventilation box 7. After the air inside the cabinet is heated, its density decreases, and it rises naturally, eventually being discharged from the air outlet 21 of the top cover 2. During this process, sand and dust in the outside air settle on the bottom plate 42 of the air chamber 4 due to gravity, and can be removed from the sand discharge port 9 by periodically opening the cover 91.

[0027] When temperature sensor 10 detects that the cabinet temperature T ≥ T1, the system enters the intelligent forced cooling mode. The controller (such as a PLC) reads the data from all wind pressure sensors 11, compares and analyzes them, and determines the current direction of the external natural wind. For example, if the wind pressure sensor on the east side has the highest reading, it is determined to be an east wind. The controller prioritizes starting the fan 72 in the ventilation box 7 located on the leeward side (i.e., the west side). After the fan 72 starts, it generates negative pressure in its corresponding air duct 5. This negative pressure causes the air pressure below the movable baffle 8 (air duct side) to be lower than above it (air chamber side). Under the action of the pressure difference, the movable baffle 8 overcomes the torsion spring force and rotates upward until the movable part 85 contacts the upper limit plate 82, and the communication port 41 is fully opened.

[0028] At this time, a large amount of outside air (containing little sand and dust) is forced in by fan 72 through the west ventilation hole 61, and is drawn into the cabinet 1 through the air chamber 4, the fully open connecting port 41, and the air duct 5. The airflow passes through the heating elements inside the cabinet, efficiently carrying away heat, and is discharged through the air outlet 21 of the top cover 2. During this process, the fans on the east side (windward side) and the north and south sides (crosswind sides) remain closed, and their corresponding movable baffles 8 are kept closed by the force of torsion springs, allowing air to enter only through the micro-holes 86. This utilizes natural wind pressure and prevents high-speed sand and dust from directly intruding into the cabinet, achieving energy-efficient and high-performance heat dissipation.

[0029] During forced cooling, temperature sensor 10 continuously monitors the temperature inside the cabinet. Once the temperature drops and meets the condition T ≤ T2, the controller shuts down all fans 72. After the fans stop, the negative pressure in the air duct 5 disappears, the movable baffle 8 resets under the action of the torsion spring, the movable part 85 re-contacts the lower limit plate 83, the connection port 41 closes, and the system automatically switches back to natural cooling mode.

[0030] The low-voltage switchgear and its heat dissipation control method provided by this invention are compact and ingeniously designed. Its unique multi-directional independent air duct and mechanical adaptive movable baffle structure, combined with an intelligent control strategy based on temperature and air pressure, not only significantly improve the heat dissipation performance of the switchgear, ensuring safe operation of the equipment under high temperature and high load, but also greatly enhance its ability to resist sand and dust and pests, and reduce maintenance costs. The cabinet is located above the ventilation box, reducing the impact of ground temperature on the internal temperature of the cabinet. This invention can be widely applied in various industrial fields with high requirements for power distribution equipment, such as power, metallurgy, chemical industry, and rail transportation. It is suitable for harsh environments with large temperature differences and abundant sand and dust, such as deserts and Gobi, and has extremely high practical value and promising prospects for promotion.

[0031] It is worth mentioning that the technical features of the fan, controller, sensor and other components involved in this patent application should be regarded as prior art. The specific structure, working principle and possible control method and spatial arrangement of these technical features can be adopted by conventional choices in the field and should not be regarded as the inventive point of this patent. This patent will not be further elaborated in detail.

[0032] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make many modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning or limited experimentation on the basis of the prior art should be within the scope of protection defined by the claims.

Claims

1. A low-voltage switchgear, comprising a cabinet body, wherein the upper part of the cabinet body is provided with a top cover, characterized in that, The upper part of the cabinet is provided with a ventilation box, which contains several ventilation structures, including air chambers and air ducts. Several ventilation zones are provided around the ventilation box, and each ventilation zone corresponds to one of the ventilation structures. Several ventilation holes are provided in each ventilation zone, and the ventilation holes are connected to the air chambers in the corresponding ventilation structures. The air duct is composed of several ventilation segments connected in sequence, with adjacent ventilation segments forming an angle of 100-160°. One end of the air duct is connected to the corresponding air chamber, and the other end is connected to the lower part of the cabinet. Several air vents are provided around the top cover, and the air vents are connected to the upper part of the cabinet.

2. The low-voltage switchgear as described in claim 1, characterized in that, The lower end of the ventilation zone is provided with a sand discharge port, which is connected to the lower end of the ventilation chamber. The sand discharge port is covered with a cover plate, which is detachably connected to the ventilation box.

3. The low-voltage switchgear as described in claim 2, characterized in that, The air chamber is surrounded by several panels, with the panel at the bottom of the air chamber serving as the base plate. The base plate is inclined and its lower end is close to the sand discharge port.

4. The low-voltage switchgear as described in claim 3, characterized in that, The lower part of the cabinet is provided with several ventilation boxes, each with a ventilation opening. A fan is installed inside the ventilation opening, and the air duct connects to the inside of the ventilation box.

5. The low-voltage switchgear as described in claim 4, characterized in that, The ventilation box has four ventilation structures and four ventilation zones, each with a different orientation. The cabinet contains four ventilation boxes.

6. The low-voltage switchgear as described in claim 5, characterized in that, The connection between the air duct and the air chamber is set as a communication port, which is set downward. A movable baffle is provided at the communication port. A rotating shaft is installed on one side of the communication port, and an upper limit plate and a lower limit plate are provided on the other side. One side of the movable baffle is set as a hinge part, and the other side is set as a movable part. The hinge part is connected to the rotating shaft in the air chamber through a bearing. The movable part moves between the upper limit plate and the lower limit plate. When the movable part contacts the upper limit plate, the communication port is in an open state. When the movable part contacts the lower limit plate, the communication port is in a closed state. The movable part is kept in contact with the lower limit plate by the elastic force of the torsion spring installed on the rotating shaft or by the weight of the movable baffle. The movable baffle is provided with several micro-holes.

7. The low-voltage switchgear as described in claim 6, characterized in that, A temperature sensor is installed inside the cabinet, and a wind pressure sensor is installed in each of the ventilation zones. The orientation of the wind pressure sensor is consistent with the orientation of the ventilation hole in the corresponding ventilation zone.

8. The low-voltage switchgear as described in claim 1, characterized in that, The air vents around the top cover are all oriented downwards.

9. The heat dissipation control method for low-voltage switchgear as described in claim 7, characterized in that, include: Natural heat dissipation mode: When the temperature sensor inside the cabinet detects that the temperature inside the cabinet is lower than the preset start threshold T1, all fans remain off. Outside airflow enters the air chamber through the ventilation holes in the ventilation area, passes through the micropores on the movable baffle, flows into the air duct, and then enters the cabinet interior through the ventilation openings of the ventilation box. The hot air inside the cabinet rises naturally due to its reduced density and is eventually exhausted through the air vents around the top cover, completing the natural convection heat dissipation cycle. Intelligent Forced Cooling Mode: When the temperature sensor detects that the temperature inside the cabinet is higher than the preset start threshold T1, the control system activates the forced cooling logic: The control system reads the wind pressure sensor data installed in each ventilation zone, analyzes and determines the current wind direction; based on the wind direction determination result, the control system prioritizes starting the fans in one or more ventilation boxes located on the leeward side; at the same time, the fans on the windward or side wind sides are kept off or at low speed; after the fans start, a negative pressure is formed in the corresponding air duct, causing a pressure difference on both sides of the movable baffle. This pressure difference overcomes the weight of the movable baffle and / or the elastic force of the torsion spring, driving the movable baffle to rotate around the pivot until its movable part contacts the upper limit plate, so that the connection port is fully opened; after the connection port is opened, a large amount of outside air is forcibly drawn into the cabinet through the ventilation holes, air chamber, connection port, and air duct under the suction of the fan, flows through the heating elements inside the cabinet, and is discharged from the air outlet of the top cover carrying heat, achieving efficient forced cooling; Heat dissipation maintenance and deactivation: During forced heat dissipation mode operation, the control system continuously monitors the temperature inside the cabinet; when the temperature inside the cabinet drops below the preset stop threshold T2, where T2 < T1, the control system controls the fan to stop operating; after the fan stops, the negative pressure in the air duct disappears, the movable baffle resets under its own weight and / or torsion spring action, its movable part re-contacts the lower limit plate, the connection port returns to the closed state, and the system automatically switches back to natural heat dissipation mode.

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