A middle high voltage switch cabinet anti-condensation contact protection device

Abstract

The application discloses a condensation-preventing contact protection device for a high-voltage switch cabinet, and relates to the technical field of high-voltage switch cabinets.The device comprises a cabinet body, a contact box fixed in the cabinet body, a connecting block fixed to the outer wall of the contact box, a sliding rod arranged on the top of the connecting block, a reset spring sleeved on the sliding rod, an annular box slidingly assembled on the sliding rod, and a gas storage box fixedly connected to the outer wall of the contact box.The device can solve the problem that, when a high-voltage switch cabinet is operated at night, the cabinet body rapidly dissipates heat, the contact box and the internal current-carrying components continue to generate heat, a significant temperature difference is formed between the inner cavity of the contact box and the environment in the cabinet, and hot and humid air condenses on the inner wall of the contact box to form condensation.The condensation can cause problems such as insulation reduction of the contact box, surface creepage, contact oxidation and corrosion, and can easily cause short circuit, equipment burning, unplanned power outage and other serious accidents, and is a core hidden danger for safe and stable operation of the high-voltage switch cabinet.

Description

Technical Field

[0001] This invention relates to the field of high-voltage switchgear technology, specifically to a centrally located high-voltage switchgear anti-condensation contact protection device. Background Technology

[0002] The contact box is an important component of the switchgear, used to install stationary contacts. It generally includes a box body, which is usually located in the busbar compartment on one side of the partition and installed on the partition inside the switchgear cabinet. The box body is connected to the truck compartment. The stationary contacts are fixed in the box body so as to connect or disconnect with the Phillips head contacts of the circuit breaker in the truck compartment.

[0003] For example, the contact box detection device for high-voltage switchgear with publication number CN111313242B can install a temperature and humidity detection and exhaust device at the connection between the stationary contact and the plum blossom contact. This allows for stable detection of the temperature and humidity inside the contact box body, as well as the detection of the temperature and humidity outside the contact box body, i.e., inside the switchgear. This enables timely removal of heat or moisture from inside the contact box body, ensuring a dry environment inside the switchgear. It also balances the temperature and humidity between the contact box body and the switchgear, effectively improving the safety performance and service life of the contact box body during use inside the switchgear. However, existing high-voltage switchgear contact boxes still have some shortcomings.

[0004] Under continuous nighttime operation, the metal casing of the existing medium-voltage switchgear rapidly exchanges heat with the external environment, and the ambient temperature inside the cabinet drops rapidly in sync with the ambient temperature. However, the core live components of the switchgear, such as the contact box and its internal moving and stationary contacts, connecting busbars, and other current-carrying elements, remain in continuous operation. The Joule heat generated during the current flow process keeps the closed inner cavity of the contact box at a relatively high temperature, thus creating a significant temperature difference between the inner cavity of the contact box and the environment inside the cabinet.

[0005] At this point, the hot, humid air inside the contact box comes into contact with the inner wall of the contact box, whose temperature has rapidly decreased along with the environment inside the cabinet. The temperature drops rapidly below the dew point, and the saturated water vapor in the air will continuously condense on the inner wall of the contact box, forming liquid condensation. The generation of condensation will directly cause a series of serious equipment safety hazards: on the one hand, condensation will significantly reduce the insulation performance of the contact box, causing surface creepage, insulation flashover, and even breakdown accidents, which can easily lead to serious faults such as phase-to-phase short circuits and cabinet explosions in the switchgear; on the other hand, condensation will cause oxidation and corrosion of metal current-carrying components such as contacts and busbars, resulting in abnormally increased contact resistance and intensified current-carrying heat generation, ultimately leading to contact burnout, unplanned power outages, and other production accidents, seriously threatening the safe and stable operation of the power system.

[0006] To address the aforementioned issues, there is an urgent need for innovative design based on the existing anti-condensation contact protection device for medium-voltage switchgear. Summary of the Invention

[0007] This invention addresses the problem of overly simplistic solutions in existing technologies by providing a significantly different approach. Specifically, it aims to offer a condensation-proof contact protection device for mid-mounted high-voltage switchgear. This addresses the issue raised in the background where, during nighttime operation, the switchgear cabinet rapidly dissipates heat, while the contact box and internal current-carrying components continue to heat up, creating a significant temperature difference between the contact box cavity and the cabinet environment. This leads to condensation of hot, humid air on the inner wall of the contact box. Condensation causes problems such as decreased insulation of the contact box, surface creepage, and contact oxidation and corrosion, easily triggering short circuits, equipment burnout, unplanned power outages, and other serious accidents. It is a core hidden danger for the safe and stable operation of high-voltage switchgear.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a mid-mounted high-voltage switchgear anti-condensation contact protection device, comprising a cabinet and a contact box fixed inside the cabinet, and a connecting block fixed to the outer wall of the contact box; A slide bar is installed at the top of the connecting block; A return spring fitted onto the slide bar; A ring-shaped box that is slidably mounted on a slide rod; A gas storage box that is fixedly connected to the outer wall of the contact box; Multiple sets of flow dividers connected to the bottom of the annular box; The array is fixed to the connecting block inside the vent groove of the contact box; Rotate the shaft mounted on the connecting block; Rotate the fan blades mounted on the shaft; A groove formed on the fan blade; A drive block that slides within the waist groove; The first connector is fixed to the end of the drive block; The connecting rods at both ends are hinged to the top of the annular box via second connectors; The annular box is filled with an insulating working fluid that can undergo a gas-liquid phase change with the ambient temperature difference. The two ends of the reset spring abut against the top of the connecting block and the bottom of the annular box, respectively. When the fan blade is closed, it covers the pre-set ventilation groove of the contact box.

[0009] Preferably, a piston plate is slidably disposed inside the gas storage box, a flexible tube is fixedly connected to the bottom of the gas storage box, the flexible tube is connected to the top of the annular box, at least three sets of sliding rods are evenly arranged along the circumference of the contact box, and the annular box is provided with guide holes corresponding to the sliding rods. The annular box is slidably sleeved on the outside of the sliding rods through the guide holes, and the return spring is sleeved on the outside of the sliding rods, with its lower end abutting against the top of the connecting block and its lower end abutting against the lower end face of the annular box.

[0010] Preferably, the flow divider is a finned thin-walled structure, and multiple sets of the flow dividers are evenly arrayed along the circumference of the annular box. The inner cavity of each set of the flow dividers is connected to the inner cavity of the annular box, and the thermal conductivity of the flow divider is the same as that of the annular box.

[0011] Preferably, the connecting block, shaft, fan blade, waist groove, drive block, and connecting rod are arranged in a one-to-one correspondence with the ventilation groove, and are evenly arranged in 5 groups along the circumference of the contact box. Each group of ventilation grooves is opened through the radial direction of the contact box. When the fan blade is closed, it is completely in contact with the outer wall of the contact box and completely covers the corresponding ventilation groove.

[0012] Preferably, the second connecting member is an insulated hinge pin, the lower end of the connecting rod is hinged to the top of the annular box through the second connecting member, and the upper end of the connecting rod is hinged to the outer wall of the drive block through the first connecting member. The length of the connecting rod is matched with the sliding stroke of the annular box and the rotation angle of the fan blade.

[0013] Preferably, when the insulating working fluid in the annular box condenses into a liquid state as the ambient temperature decreases, the liquid working fluid is diverted to each diversion plate, increasing the total weight of the annular box and the diversion plate. This increases the weight of the annular box and the diversion plate, allowing it to overcome the spring force of the return spring and slide downwards along the slide rod. The connecting rod pulls the drive block to slide along the waist groove, causing the fan blades to rotate around the shaft and open the ventilation slot, thus connecting the inner cavity of the contact box with the inner cavity of the cabinet and balancing the temperature and humidity.

[0014] Preferably, the waist groove is formed along the length of the fan blade, and the two ends of the waist groove are rounded. The drive block is a cylindrical insulating pin with its outer diameter clearance matching the width of the waist groove. The drive block can slide smoothly along the length of the waist groove.

[0015] Preferably, when the ambient temperature rises, the liquid working fluid in the diverter plate evaporates into a gaseous state and flows back into the annular box, reducing the total weight of the annular box. The return spring rebounds and pushes the annular box to return to its original position along the slide bar. The connecting rod pushes the drive block to slide in the opposite direction along the waist groove, causing the fan blade to rotate in the opposite direction around the shaft and close the ventilation groove.

[0016] Preferably, an insulating silicone rubber sealing gasket is adhered to the side of the fan blade facing the contact box. When the fan blade is closed, the sealing gasket is fully pressed against the outer wall of the contact box to achieve sealing of the vent groove. The two ends of the shaft are rotatably assembled with the connecting block through polytetrafluoroethylene bushings.

[0017] Preferably, the inner cavity of the annular box is divided into independent sealed cavities corresponding to the flow dividers, each cavity is connected to the corresponding flow divider, the insulating working fluid is perfluorohexane, the connecting rods corresponding to each set of fan blades have the same length, and when the annular box slides down, it drives all fan blades to rotate synchronously to open and close.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention adopts a passive gravity-driven method based on temperature difference gas-liquid phase change to achieve adaptive opening and closing of the venting slot in the contact box. The entire process requires no external power supply, sensors, or electronic control components, and no manual intervention. It is suitable for the field operation conditions of 630-1250 type cable outlet cabinets. There is no need to install auxiliary devices such as heating and dehumidification inside the cabinet. The opening and closing of the venting slot directly balances the temperature and humidity inside and outside the contact box, eliminating the conditions for condensation on the inner wall of the contact box from the root. This solves the industry pain point that existing anti-condensation solutions cannot target the condensation inside the contact box cavity, significantly reducing the probability of phase-to-phase short circuits and contact burnout caused by condensation in 630-1250 type cable outlet cabinets, and effectively ensuring the safe and stable operation of the power system. 2. This invention has strong structural adaptability, taking into account both high-voltage insulation safety and convenient on-site installation. The entire device is made of epoxy insulation material. When the fan blades are closed, they are completely in contact with the outer wall of the contact box, with no protrusions or sharp corners, eliminating the risk of electric field concentration and partial discharge. It meets the insulation standard requirements of 10kV high-voltage switchgear. At the same time, the finned shunt plate significantly increases the working fluid evaporation contact area, accelerating the device reset efficiency. Multiple sets of synchronous linkage structures ensure that all fan blade opening and closing actions are synchronous and stable. The device operates without jamming, requires no maintenance, and has a long service life. It takes into account multiple core requirements such as contact box sealing protection, ventilation and anti-condensation, and high-voltage insulation safety. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the medium-voltage switchgear of the present invention.

[0020] Figure 2 This is a schematic diagram of the overall structure of the centrally located high-voltage switchgear of the present invention from another angle.

[0021] Figure 3 This is a schematic diagram of the internal structure of the medium-voltage switchgear of the present invention.

[0022] Figure 4 This is a schematic diagram of the contact box structure of the present invention.

[0023] Figure 5 This is a schematic diagram of the overall driving structure of the contact box of the present invention.

[0024] Figure 6 This is a schematic diagram of the condensation triggering structure of the present invention.

[0025] Figure 7 This is a schematic diagram of the fan blade ventilation structure of the present invention.

[0026] Figure 8 This is a schematic diagram of the fan blade rotation frame of the present invention.

[0027] Figure 9 for Figure 7 An enlarged schematic diagram of the structure at point A.

[0028] Figure 10 This is a schematic diagram of the gas storage box of the present invention.

[0029] In the diagram: 1. Cabinet; 2. Contact box; 3. Connecting block; 4. Slide rod; 5. Return spring; 6. Annular box; 601. Gas storage box; 602. Piston plate; 603. Hose; 7. Diverter plate; 8. Connecting block; 9. Shaft; 10. Fan blade; 11. Waist groove; 12. Drive block; 13. First connecting piece; 14. Connecting rod; 15. Second connecting piece. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Please see Figures 1 to 9 The present invention provides a technical solution: a mid-mounted high-voltage switchgear anti-condensation contact protection device, including a cabinet 1 and a contact box 2 fixed inside the cabinet 1, and also includes a connecting block 3 fixed to the outer wall of the contact box 2; The slide bar 4 is set at the top of the connecting block 3; A return spring 5 sleeved on the slide rod 4; An annular box 6 is slidably mounted on the slide rod 4; Gas storage box 601 is fixedly connected to the outer wall of the contact box (2); Multiple sets of diversion plates 7 connected to the bottom of the annular box 6; The array is fixed to the connecting block 8 inside the vent groove of the contact box 2; Rotate the shaft 9 mounted on the connecting block 8; Rotate the fan blade 10 mounted on the shaft 9; A groove 11 is formed on the fan blade 10; A drive block 12 is slidably fitted into the waist groove 11; The first connector 13 is fixed to the end of the drive block 12; The two ends are respectively connected to the top of the annular box 6 by the second connector 15; The annular box 6 is filled with an insulating working fluid that can undergo gas-liquid phase change with the ambient temperature difference. The two ends of the return spring 5 abut against the top of the connecting block 3 and the bottom of the annular box 6, respectively. When the fan blade 10 is closed, it covers the pre-set ventilation groove of the contact box 2.

[0032] In this embodiment, cabinet 1 is a 630-1250 type cable outlet cabinet. The contact box 2 is a 630A / 1250A epoxy insulated contact box 2 that matches the cabinet type. It is fixed to the rear insulating partition of cabinet 1 by high-strength bolts. The front end of the contact box 2 extends into the circuit breaker compartment and is plugged into the staggered contacts of the circuit breaker trolley. The rear end extends into the cable compartment and is connected to the cable joint and the outgoing busbar, forming a complete current-carrying circuit. The outer wall of the cable compartment section of the contact box 2 has a radially penetrating ventilation groove to achieve air circulation and temperature and humidity balance between the inner cavity of the contact box 2 and the cable compartment of cabinet 1. The connecting block 3 is an L-shaped epoxy insulated mounting base, which is integrally injection molded with the contact box 2 using the same epoxy resin material. It can also be fixed to the outer flange step of the contact box 2 by epoxy structural adhesive without drilling or tapping the contact box 2 body, thus not damaging its original insulation structure and mechanical strength. The slide rod 4 is an epoxy fiberglass insulated round rod, with its lower end locked to the top face of the connecting block 3. The axis of the slide rod 4 is parallel to the central axis of the contact box 2 and arranged vertically, providing precise guidance for the vertical sliding of the annular box 6. The return spring 5 is a PTFE-coated stainless steel insulated spring, sleeved on the outside of the slide rod 4, providing an upward return force for the annular box 6. Its elastic coefficient is precisely matched with the total weight after the working fluid is liquefied, ensuring that the annular box 6 can slide down stably after the working fluid is liquefied and can return smoothly after the working fluid evaporates. The annular box 6 is an annular epoxy insulated box arranged coaxially with the contact box 2. A safety gap is reserved between its inner wall and the outer wall of the contact box 2 to avoid frictional interference during sliding. The insulating working fluid filled in the box is perfluorohexane, with a boiling point of 56℃, an insulation strength ≥16kV / mm, non-flammable and chemically stable, perfectly adapting to the standard operating temperature range of -5℃ to 40℃ for the 630-1250 type outgoing cabinet. The flow divider 7 is a finned, thin-walled structure made of high thermal conductivity epoxy material. Its inner cavity is connected to the inner cavity of the annular box 6. The liquefied working fluid can flow into the flow divider 7 and spread out evenly, greatly increasing the contact area between the working fluid and the ambient air, accelerating the evaporation and reflux rate, and also acting as a counterweight to stabilize the flow and prevent the annular box 6 from tilting and getting stuck when it slides down. The connecting block 8 is an epoxy-insulated support, bonded and fixed to the inner edge of the ventilation groove, providing installation support for the shaft 9. The shaft 9 is an epoxy-glass fiber insulated round rod, whose axis is parallel to the central axis of the contact box 2. Both ends are rotatably assembled with the connecting block 8 through self-lubricating bushings. The shaft 9 is installed on the inner edge of the fan blade 10 near the contact box 2, maximizing the rotational lever arm to meet the requirements of passive gravity drive. The fan blade 10 is an arc-shaped epoxy plate with the same curvature as the outer wall of the contact box 2. Its inner edge is fixedly connected to the shaft 9 and can rotate synchronously with the shaft 9. Its size is larger than the ventilation groove, and it can completely cover the ventilation groove when closed. The waist groove 11 is formed along the length of the fan blade 10 on the outer half of the fan blade 10. The drive block 12 is a cylindrical epoxy-insulated pin that is clearance-fitted with the waist groove 11 and can slide smoothly along the length of the waist groove 11. The first connecting piece 13 is fixed to the extended end of the drive block 12 and is used to achieve hinge connection with the connecting rod 14.The second connector 15 is an epoxy-insulated hinge pin, and the connecting rod 14 is an epoxy-insulated straight rod. Its upper and lower ends are respectively hinged to the first connector 13 and the top of the annular box 6 through the second connector 15. The length of the connecting rod 14 is precisely matched with the sliding stroke of the annular box 6 and the rotation angle of the fan blade 10, with no dead points or interference between parts throughout the entire process.

[0033] A piston plate 602 is slidably disposed inside the gas storage box 601. A hose 603 is fixedly connected to the bottom of the gas storage box 601. The hose (603) is connected to the top of the annular box (6). At least three sets of slide rods 4 are evenly arranged along the circumference of the contact box 2. The annular box 6 is provided with guide holes corresponding to the slide rods 4. The annular box 6 is slidably sleeved on the outside of the slide rods 4 through the guide holes. The return spring 5 is sleeved on the outside of the slide rods 4. Its lower end abuts against the top of the connecting block 3 and its lower end abuts against the lower end face of the annular box 6.

[0034] In this embodiment, the volume expansion caused by gas evaporation allows excess gaseous working fluid to enter the gas storage box 601 through the insulating hose 603. The gaseous working fluid pushes the piston plate 602 upward. During the upward movement of the piston plate 602, the air in the air balance chamber is smoothly discharged through the top micro-pressure vent. The working fluid is completely sealed within the working fluid buffer chamber and the annular box 6 throughout the entire process, with no leakage or mass loss. At the same time, a stable saturated vapor pressure can still be established within the annular box 6. (It should be noted that the gas storage box 601 is integrally injection molded from epoxy resin of the same material as the annular box 6. The piston plate 602 is an epoxy insulating board covered with polytetrafluoroethylene, with a high and low temperature resistant fluororubber sealing ring embedded in the outer ring, completely dividing the inner cavity of the gas storage box 601 into two independent cavities that are not connected and do not allow gas leakage. The lower cavity is the working fluid buffer chamber, and the upper cavity is the air balance chamber. The hose 603...) 3 is made of polytetrafluoroethylene (PTFE), and its two ends are sealed to the closed working fluid chamber of the annular box 6 and the working fluid buffer chamber of the gas storage box 601 respectively through sealed joints, ensuring no leakage and no bending interference throughout the process. The length of the hose 603 is adapted to the sliding stroke of the annular box 6. ), The slide rod 4 is evenly arranged in 3 sets at 120° along the circumference of the contact box 2. Each slide rod 4 has a diameter of 6mm and a length of 80mm, providing a maximum vertical sliding stroke of 25mm for the annular box 6; the guide hole of the annular box 6 is fitted with a PTFE self-lubricating bushing, and the slide rod 4 passes through the guide hole, achieving smooth vertical sliding of the annular box 6 through three-point guidance, completely avoiding skew and jamming problems; the return spring 5 has a wire diameter of 0.8mm, a median diameter of 5mm, an effective number of 15 turns, an elastic coefficient of 5N / mm, and a preload of 10N, precisely matching the total weight of 25N after the working fluid is liquefied, ensuring stable and reliable drive and reset actions.

[0035] The flow divider 7 has a finned thin-walled structure. Multiple flow dividers 7 are evenly arranged in an array along the circumference of the annular box 6. The inner cavity of each flow divider 7 is connected to the inner cavity of the annular box 6. The thermal conductivity of the flow divider 7 is the same as that of the annular box 6.

[0036] In this embodiment, the thickness of the flow divider plate 7 is only 1.5 mm, and it is evenly arranged in 5 groups along the circumference of the annular box 6. Each group corresponds to an independent compartment of the annular box 6, and its inner cavity is completely connected to the corresponding compartment. The liquefied working fluid can flow naturally into the flow divider plate 7 and spread out under the action of gravity. Compared with the structure where only the annular box 6 stores liquid, the contact area between the working fluid and the ambient air can be increased by more than 4 times, which greatly accelerates the evaporation and reflux speed of the working fluid and improves the reset efficiency of the device. The flow divider plate 7 and the annular box 6 are integrally injection molded with the same high thermal conductivity epoxy resin, and the thermal conductivity is completely consistent. At the same time, it can play a counterweight and flow stabilization role, avoiding the problem of uneven weight, tilting and jamming due to the flow of working fluid during the downward movement of the annular box 6.

[0037] Connecting block 8, shaft 9, fan blade 10, waist groove 11, drive block 12 and connecting rod 14 are arranged one-to-one with the ventilation groove, and are evenly arranged in 5 groups along the circumference of the contact box 2. Each group of ventilation grooves is opened through the radial direction of the contact box 2. When the fan blade 10 is closed, it is completely attached to the outer wall of the contact box 2 and completely covers the corresponding ventilation groove.

[0038] In this embodiment, the connecting block 8, shaft 9, fan blade 10, venting groove, and connecting rod 14 are arranged in five groups at a 72° angle along the circumference of the contact box 2. The dimensions of a single venting groove are 40mm in axial length and 15mm in circumferential width. The total ventilation area of ​​the five groups of venting grooves can meet the anti-condensation requirements of five complete air exchanges within the cavity of the contact box 2 within one hour. The dimensions of the fan blade 10 adapted to the 1250A contact box are 45mm in axial length and 20mm in circumferential width, and the dimensions of the fan blade 10 adapted to the 630A contact box are 35mm in axial length and 16mm in circumferential width. The dimensions are larger than the corresponding venting grooves. When closed, they fit completely against the outer wall of the contact box 2 without any warping or gaps, and can completely cover the corresponding venting grooves to ensure sealing and insulation performance.

[0039] The second connecting member 15 is an insulated hinge pin. The lower end of the connecting rod 14 is hinged to the top of the annular box 6 through the second connecting member 15, and the upper end of the connecting rod 14 is hinged to the outer wall of the drive block 12 through the first connecting member 13. The length of the connecting rod 14 matches the sliding stroke of the annular box 6 and the rotation angle of the fan blade 10.

[0040] In this embodiment, the second connector 15 is an epoxy-insulated hinged pin, and the connecting rod 14 is an epoxy-insulated straight rod. Its lower end is hinged to the top end face of the annular box 6 through the second connector 15, and its upper end is hinged to the first connector 13 through the second connector 15. The length of the connecting rod 14 is precisely matched with the maximum sliding stroke of the annular box 6 and the maximum rotation angle of the fan blade. When the annular box 6 slides down 20mm, the connecting rod 14 can drive the fan blade 10 to rotate 75° around the shaft 9, fully exposing the ventilation groove, achieving maximum ventilation volume, with no dead points or component interference throughout the process.

[0041] When the insulating working fluid inside the annular box 6 condenses into a liquid as the ambient temperature decreases, the liquid working fluid is diverted to each diversion plate 7. The total weight of the annular box 6 and the diversion plate 7 increases, which overcomes the elastic force of the return spring 5 and slides downward along the slide rod 4. Through the connecting rod 14, the drive block 12 is pulled to slide along the waist groove 11, which drives the fan blade 10 to rotate around the shaft rod 9 to open the ventilation groove, so that the inner cavity of the contact box 2 is connected to the inner cavity of the cabinet 1 and the temperature and humidity are balanced.

[0042] In this embodiment, during nighttime operation, the ambient temperature of the cable compartment in cabinet 1 drops rapidly. The gaseous perfluorohexane working fluid in the annular box 6 condenses into a liquid upon cooling and is diverted to each diversion plate 7. The total weight of the annular box 6 and the diversion plate 7 increases and overcomes the preload of the return spring 5, sliding down 20mm along the slide rod 4. During the sliding process, the hinged connecting rod 14 pulls the drive block 12 to slide down along the waist groove 11, causing the fan blade 10 to rotate outward 75° around the shaft rod 9, fully opening the ventilation slot, connecting the inner cavity of the contact box 2 with the cable compartment of cabinet 1, realizing rapid exchange of internal and external air, balancing the temperature and humidity inside and outside the contact box 2, and eliminating the conditions for condensation on the inner wall from the root.

[0043] The waist groove 11 is opened along the length direction of the fan blade 10. The two ends of the waist groove 11 are rounded. The drive block 12 is a cylindrical insulating pin. Its outer diameter is clearance-fitted with the width of the waist groove 11. The drive block 12 can slide smoothly along the length direction of the waist groove 11.

[0044] In this embodiment, the waist groove 11 is opened along the length direction of the fan blade 10, with a length of 22mm and a width of 4.2mm. The two ends are rounded to avoid jamming when the drive block 12 slides to the limit position. The drive block 12 is a cylindrical epoxy-insulated pin with a single-sided gap of 0.2mm between it and the waist groove 11. It can slide smoothly along the length direction of the waist groove 11 without jamming or slipping, perfectly adapting to the transmission angle change during the downward slide of the annular box 6, and realizing a smooth conversion from linear motion to rotational motion.

[0045] When the ambient temperature rises, the liquid working fluid in the diverter plate 7 evaporates into gas and flows back into the annular box 6. The total weight of the annular box 6 decreases, and the return spring 5 rebounds and pushes the annular box 6 to return to its original position along the slide bar 4. Through the connecting rod 14, the drive block 12 is pushed to slide in the opposite direction along the waist groove 11, which drives the fan blade 10 to rotate in the opposite direction around the shaft 9 to close the ventilation groove.

[0046] In this embodiment, when the ambient temperature rises during the day, the liquid perfluorohexane working fluid in the diverter plate 7 rapidly evaporates into a gaseous state and flows back into the annular box 6. The total weight of the annular box 6 gradually decreases, and the return spring 5 rebounds and pushes the annular box 6 to return to its initial high position along the slide rod 4. During the reset process, the connecting rod 14 pushes the drive block 12 to slide in the opposite direction along the waist groove 11, causing the fan blade 10 to rotate in the opposite direction around the shaft rod 9, re-closing the ventilation groove, restoring the sealed and insulating state of the contact box 2, and preparing for the next nighttime anti-condensation.

[0047] An insulating silicone rubber sealing gasket is bonded to the side of the fan blade 10 facing the contact box 2. When the fan blade 10 is closed, the sealing gasket is completely pressed against the outer wall of the contact box 2 to achieve the sealing of the ventilation groove. The two ends of the shaft 9 are rotatably assembled with the connecting block 8 through polytetrafluoroethylene bushings.

[0048] In this embodiment, a 1mm thick room temperature vulcanized silicone rubber insulating gasket is bonded to the side of the fan blade 10 facing the contact box 2. When the fan blade 10 is closed, the gasket is completely pressed against the outer wall of the contact box 2 to seal the ventilation groove, prevent moisture and dust from the cable chamber from entering the inner cavity of the contact box 2, ensure insulation performance, and avoid the risk of electric field concentration and partial discharge in the closed state. The two ends of the shaft 9 are rotated and assembled with the connecting block 8 through polytetrafluoroethylene self-lubricating bushings. The friction coefficient is low, which can achieve smooth and non-jamming self-rotation and adapt to the low tensile force requirements of passive gravity drive.

[0049] The inner cavity of the annular box 6 is divided into independent sealed cavities corresponding to the diverter plates 7. Each cavity is connected to the corresponding diverter plate 7. The insulating working fluid is perfluorohexane. The connecting rods 14 corresponding to each set of fan blades 10 have the same length. When the annular box 6 slides down, it drives all fan blades 10 to rotate and open and close synchronously.

[0050] In this embodiment, the inner cavity of the annular box 6 is divided into 5 independent sealed cavities corresponding to the flow divider 7. Each cavity is connected to the inner cavity of the corresponding flow divider 7. The perfluorohexane working fluid filling volume of a single cavity is 15ml, which can avoid the problem of uneven weight, skew and jamming caused by the random flow of the working fluid in the annular box 6. The length and installation angle of the connecting rod 14 corresponding to each set of fan blades 10 are completely consistent. When the annular box 6 slides down, it can drive the 5 sets of fan blades 10 to rotate and open and close synchronously. The force is uniform and there is no off-center load. The opening and closing of the ventilation slot is synchronous, ensuring the temperature and humidity balance efficiency and sealing and insulation performance.

[0051] Working principle: When using the anti-condensation contact protection device for the mid-mounted high-voltage switchgear, firstly, the annular box 6 filled with perfluorohexane insulating medium is assembled on the slide rod 4, the return spring 5 is installed in place accordingly, the insulating hose 603 is connected to the top of the annular box 6 to complete the pre-installation of the gas buffer assembly, and then the pre-installed device is fixed to the outer wall of the contact box 2 inside the cabinet 1 to complete the overall assembly.

[0052] Under normal daytime operating conditions, the ambient temperature inside the cable compartment of cabinet 1 remains at a high level due to the heat generated by the current carrying capacity. The perfluorohexane working fluid in the ring box 6 remains in a gaseous state. The total weight of the ring box 6 and the shunt plate 7 is relatively light. The elastic force of the return spring 5 pushes the ring box 6 to remain in the upper high position of the slide rod 4. At this time, the connecting rod 14 pushes the drive block 12 to the upper end of the waist groove 11. The fan blade 10 remains in a closed state, completely covering the ventilation groove of the contact box 2. The sealing gasket achieves a tight seal, ensuring the insulation performance and internal electric field uniformity of the contact box 2, and meeting the insulation requirements for normal daytime operation of the outgoing cabinet. During this process, the volume expansion caused by the evaporation of the working fluid allows the excess gaseous working fluid to enter the working fluid buffer chamber of the gas storage box 601 through the insulating hose 603. The gaseous working fluid pushes the piston plate 602 upward. During the upward movement of the piston plate 602, the air in the air balance chamber is smoothly discharged through the top micro-pressure vent. The working fluid is completely sealed in the working fluid buffer chamber and the annular box 6 throughout the process, with no leakage and no mass loss. At the same time, a stable saturated vapor pressure can still be established in the annular box 6 to ensure the stable execution of the reset action. During continuous nighttime operation, the metal casing of cabinet 1 rapidly exchanges heat with the low-temperature external environment, causing a rapid drop in the ambient temperature of the cable compartment at the bottom of cabinet 1. Meanwhile, the moving and stationary contacts, busbars, and other current-carrying components inside contact box 2 continue to operate under load and generate heat, creating a significant temperature difference environment within contact box 2: high internal temperature and low external temperature. At this time, the gaseous perfluorohexane working fluid in annular box 6 condenses into a liquid state upon cooling. Under gravity, the liquid working fluid is diverted to the various distribution plates 7. The annular box 6 and... The total weight of the diverter plate 7 increases significantly, overcoming the elastic force of the return spring 5 and sliding downward along the slide rod 4. During the downward movement of the annular box 6, the drive block 12 is pulled downward along the waist groove 11 by the hinged connecting rod 14, which in turn drives the fan blade 10 to rotate outward around the shaft rod 9, opening the ventilation slot and connecting the inner cavity of the contact box 2 with the inner cavity of the cable compartment of the cabinet 1, realizing rapid exchange of air between the inside and outside, balancing the temperature and humidity inside and outside the contact box 2, and eliminating the conditions for condensation on the inner wall of the contact box 2 from the root. During this process, the volume contraction caused by the liquefaction of the working fluid causes the gaseous working fluid in the working fluid buffer chamber to flow back into the annular box 6. The piston plate 602 returns to its original position under the action of gravity, and the air re-enters the air balance chamber through the micro-pressure breathing hole. Throughout the process, the decrease of the saturated vapor pressure and the establishment of the pressure difference driving force in the annular box 6 are not affected, ensuring the accurate execution of the downward trigger action of the device.

[0053] When the ambient temperature rises during the day, the liquid perfluorohexane working fluid in the diverter plate 7 evaporates rapidly into a gaseous state and flows back into the annular box 6. The total weight of the annular box 6 gradually decreases, and the return spring 5 rebounds to push the annular box 6 to return to its original position along the slide rod 4. Through the connecting rod 14, the drive block 12 slides in the opposite direction along the waist groove 11, causing the fan blade 10 to rotate in the opposite direction around the shaft rod 9, reclosing the ventilation groove, restoring the sealed and insulating state of the contact box 2, and preparing for the next nighttime anti-condensation action.

[0054] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A mid-mounted high-voltage switchgear anti-condensation contact protection device, comprising a cabinet (1) and a contact box (2) fixed inside the cabinet (1), characterized in that: It also includes a connecting block (3) fixed to the outer wall of the contact box (2); A slide bar (4) is set on top of the connecting block (3); A return spring (5) sleeved on the slide bar (4); A ring box (6) is slidably mounted on a slide bar (4); Gas storage box (601) is fixedly connected to the outer wall of the contact box (2); Multiple sets of diversion plates (7) connected to the bottom of the annular box (6); The array is fixed in the venting groove of the contact box (2) and the connecting block (8); Rotate the shaft (9) mounted on the connecting block (8); Rotate the fan blade (10) mounted on the shaft (9); Waist groove (11) is formed on the fan blade (10); A drive block (12) is slidably fitted into the waist groove (11); The first connector (13) is fixed to the end of the drive block (12); The connecting rods (14) are hinged to the top of the annular box (6) at both ends via the second connector (15); The annular box (6) is filled with an insulating working fluid that can undergo gas-liquid phase change with the ambient temperature difference. The two ends of the reset spring (5) abut against the top of the connecting block (3) and the bottom of the annular box (6) respectively. When the fan blade (10) is closed, it covers the pre-set ventilation groove of the contact box (2).

2. The anti-condensation contact protection device for a centrally located high-voltage switchgear according to claim 1, characterized in that: A piston plate (602) is slidably disposed inside the gas storage box (601). A hose (603) is fixedly connected to the bottom of the gas storage box (601). The hose (603) is connected to the top of the annular box (6). At least three sets of sliding rods (4) are evenly arranged along the circumference of the contact box (2). The annular box (6) is provided with guide holes corresponding to the sliding rods (4). The annular box (6) is slidably sleeved on the outside of the sliding rods (4) through the guide holes. The reset spring (5) is sleeved on the outside of the sliding rods (4). Its lower end abuts against the top of the connecting block (3) and its lower end abuts against the lower end face of the annular box (6).

3. The anti-condensation contact protection device for a centrally located high-voltage switchgear according to claim 1, characterized in that: The flow divider (7) is a finned thin-walled structure. Multiple sets of flow dividers (7) are evenly arrayed along the circumference of the annular box (6). The inner cavity of each set of flow dividers (7) is connected to the inner cavity of the annular box (6). The thermal conductivity of the flow divider (7) is consistent with that of the annular box (6).

4. The anti-condensation contact protection device for a centrally located high-voltage switchgear according to claim 1, characterized in that: The connecting block (8), shaft (9), fan blade (10), waist groove (11), drive block (12) and connecting rod (14) are arranged in a one-to-one correspondence with the ventilation groove, and are evenly arranged in 5 groups along the circumference of the contact box (2). Each group of ventilation grooves is opened through the radial direction of the contact box (2). When the fan blade (10) is closed, it is completely attached to the outer wall of the contact box (2) and completely covers the corresponding ventilation groove.

5. The anti-condensation contact protection device for a centrally located high-voltage switchgear according to claim 1, characterized in that: The second connector (15) is an insulated hinge pin. The lower end of the connecting rod (14) is hinged to the top of the annular box (6) through the second connector (15). The upper end of the connecting rod (14) is hinged to the outer wall of the drive block (12) through the first connector (13). The length of the connecting rod (14) matches the sliding stroke of the annular box (6) and the rotation angle of the fan blade (10).

6. The anti-condensation contact protection device for a centrally located high-voltage switchgear according to claim 1, characterized in that: When the insulating working fluid in the annular box (6) condenses into liquid as the ambient temperature decreases, the liquid working fluid is diverted to each diversion plate (7). The total weight of the annular box (6) and the diversion plate (7) increases, overcoming the elastic force of the reset spring (5) and sliding down along the slide rod (4). The drive block (12) is pulled along the waist groove (11) by the connecting rod (14), which drives the fan blade (10) to rotate around the shaft (9) to open the ventilation groove, so that the inner cavity of the contact box (2) is connected to the inner cavity of the cabinet (1) and the temperature and humidity are balanced.

7. The anti-condensation contact protection device for a centrally located high-voltage switchgear according to claim 1, characterized in that: The waist groove (11) is opened along the length direction of the fan blade (10). The two ends of the waist groove (11) are rounded. The drive block (12) is a cylindrical insulating pin. Its outer diameter is fitted with the width of the waist groove (11). The drive block (12) can slide smoothly along the length direction of the waist groove (11).

8. A mid-mounted high-voltage switchgear anti-condensation contact protection device according to claim 6, characterized in that: When the ambient temperature rises, the liquid working fluid in the diversion plate (7) evaporates into gas and flows back into the annular box (6). The total weight of the annular box (6) decreases, and the reset spring (5) rebounds and pushes the annular box (6) to reset upward along the slide bar (4). The connecting rod (14) pushes the drive block (12) to slide in the opposite direction along the waist groove (11), causing the fan blade (10) to rotate in the opposite direction around the shaft (9) to close the ventilation groove.

9. A mid-mounted high-voltage switchgear anti-condensation contact protection device according to claim 1, characterized in that: An insulating silicone rubber sealing gasket is bonded to the side of the fan blade (10) facing the contact box (2). When the fan blade (10) is closed, the sealing gasket is fully pressed against the outer wall of the contact box (2) to achieve the sealing of the ventilation groove. The two ends of the shaft (9) are rotatably assembled with the connecting block (8) through polytetrafluoroethylene bushings.

10. A mid-mounted high-voltage switchgear anti-condensation contact protection device according to claim 1, characterized in that: The inner cavity of the annular box (6) is divided into independent sealed cavities corresponding to the flow dividers (7). Each cavity is connected to the corresponding flow divider (7). The insulating working fluid is perfluorohexane. The connecting rods (14) corresponding to each set of fan blades (10) have the same length. When the annular box (6) slides down, it drives all the fan blades (10) to rotate and open and close synchronously.

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