High-safety ring main unit

Abstract

The invention relates to a high-safety ring main unit, and relates to the technical field of electrical equipment, the high-safety ring main unit comprises a cabinet body, the cabinet body is provided with an overheat pressure relief device and a pressure balance device, and a driving component of the overheat pressure relief device is a driving element made of shape memory alloy to control a pull plate to slide to open a flashboard to release hot pressing in the cabinet body. A flexible diaphragm of the pressure balancing device is matched with the cabinet body and the thermal pressure relief device to form an airtight space, and the internal and external pressure difference of the box body is compensated through deformation after the overheating pressure relief device acts to relieve pressure. The ring main unit achieves the technical effects of effectively releasing the hot pressure in the cabinet body, compensating the pressure difference inside and outside the box body, improving the safety of the ring main unit and the like.

Description

Technical Field

[0001] This application relates to the field of electrical equipment technology, and in particular to a high-safety ring main unit. Background Technology

[0002] Ring main units (RNBs), as crucial electrical equipment in power systems, are widely used in urban power grids, industrial power consumption, and many other fields. With the continuous growth of electricity demand and the increasing complexity of power grids, the safety and reliability of RNBs are receiving increasing attention. Their stable operation not only affects the continuity of power supply but also plays a key role in ensuring industrial production and residents' lives. A high-performance RNB can effectively reduce the occurrence of power outages, minimize economic losses and social impacts caused by power outages, and promote the efficient development of the power industry.

[0003] In related technologies, a single pressure relief device is typically used to address potential overheating and abnormal pressure issues within the cabinet. When a fault such as arcing occurs in the electrical components inside the cabinet, causing pressure to rise, the pressure relief device will activate, releasing the internal pressure to prevent catastrophic accidents such as cabinet explosions. Furthermore, pressure balance and condensation prevention during normal operation of the ring main unit are generally addressed through simple ventilation structures or moisture-proof materials, utilizing natural ventilation or the moisture-absorbing properties of the materials to maintain a stable environment inside the cabinet.

[0004] However, existing technologies have significant drawbacks. A single pressure relief device only functions when a fault occurs, lacking comprehensive safety protection throughout the ring main unit's lifecycle. It cannot provide effective protection under normal conditions, nor can it provide secondary protection after a fault. Furthermore, after the pressure relief device is activated, a negative pressure quickly forms, allowing external contaminants to easily penetrate the cabinet and damage electrical components. Simultaneously, traditional pressure balancing and anti-condensation methods have limited effectiveness and cannot adapt well to complex and changing operating environments. They are prone to insulation failures due to condensation and corrosion, affecting the long-term reliability of the ring main unit. Summary of the Invention

[0005] The purpose of this application is to overcome the above-mentioned technical problems and provide a highly secure ring main unit.

[0006] A high-safety ring main unit includes a cabinet, the cabinet including an overheat relief device and a pressure balancing device; The overheat relief device includes: The mounting base is set on a pre-set opening on the surface of the cabinet; A gate is mounted on a mounting base and is hinged to a pull plate, which is slidably mounted within the mounting base. A drive assembly, disposed within a mounting base, includes a drive element made of a shape memory alloy; When the temperature inside the cabinet rises and triggers the drive element, the drive element controls the sliding plate to slide and open the gate, thereby releasing the heat pressure inside the cabinet. The pressure balancing device includes: The mounting bracket is installed inside the cabinet and its interior is used to house electrical components. A flexible diaphragm is installed on the outer surface of the mounting frame, which works with the cabinet and the heat relief device to form an airtight space inside the mounting frame; The overheat relief device is fluidly connected to the pressure balancing device, and the flexible diaphragm is configured to compensate for the pressure difference between the inside and outside of the chamber by deformation after the overheat relief device is activated and relieves pressure.

[0007] By adopting the above technical solutions, a full-cycle safety protection system of "active + passive" is constructed. The overheating pressure relief device provides active safety intervention when a fault occurs, and quickly relieves pressure to prevent catastrophic accidents; the pressure balancing device provides passive protection under normal conditions and secondary protection after a fault; it produces a non-obvious synergistic effect. The pressure balancing device responds quickly after pressure relief, making up for the inherent defects of a simple pressure relief device; it improves the overall reliability and environmental adaptability of the equipment, improves the internal microenvironment of the cabinet, reduces the probability of insulation faults caused by condensation and corrosion, and is suitable for harsh environments.

[0008] Optionally, the drive assembly includes a sliding seat disposed on the surface of the mounting bracket, a trigger plate slidably disposed on the sliding seat, and a drive element disposed between the trigger plate and the sliding seat; a drive groove is opened in the mounting base, a pull plate is slidably disposed in the drive groove, and a support plate is disposed on the pull plate that coincides with the projection of the trigger plate; when the temperature rises, the drive element controls the trigger plate to slide in the sliding seat and abut against the support plate of the pull plate. When the trigger plate abuts against the support plate, it drives the pull plate to slide towards the bottom of the drive groove, so that the gate rotates along the mounting base at the opening of the drive groove and gradually extends into the drive groove.

[0009] By adopting the above technical solutions, the overall reliability and environmental adaptability of the equipment are improved, and the long-term operational reliability of the ring main unit is comprehensively enhanced, making it particularly suitable for harsh environments. At the same time, it ensures the determinism and reliability of the action, with a direct and efficient force transmission path, low energy loss, fast action response, and accurate action triggering, eliminating the possibility of erroneous or non-action, greatly improving the reliability of the safety device. Moreover, the structural layout is compact and reasonable, which is conducive to the optimization of the overall structure.

[0010] Optionally, the trigger plate is equipped with a drive plate, and the mounting base is equipped with a transmission gear set controlled by the drive plate. The transmission gear set is connected to a brake bolt. Under normal conditions, the brake bolt extends into the gate plate. When the trigger plate slides and drives the transmission gear set through the drive plate, the brake bolt retracts from the gate plate.

[0011] By adopting the above technical solution, mechanical locking and linkage unlocking functions are added, achieving absolute safety under normal conditions and precise release in case of failure, providing dual safety guarantees, with ingenious linkage design, and the ability to convert and optimize the motion mode.

[0012] Optionally, a ratchet and a pawl are provided inside the mounting base; the ratchet is connected to the transmission gear set, and several metal plates are inclined downward on the drive plate, with the metal plates extending into the corresponding ratchet tooth grooves. When the temperature rises, the drive plate controls the ratchet to rotate through the metal plates, which in turn causes the transmission gear set to run; the pawl is rotatably connected to the brake bolt. When the brake bolt is removed from the brake plate, the brake bolt pushes the pawl to rotate, causing the pawl to extend into the ratchet tooth grooves.

[0013] By adopting the above technical solution, introducing state latching and unidirectional drive mechanism, the fault state can be reliably maintained. It has a sophisticated unidirectional drive design and conforms to the "fail-safe" principle.

[0014] Optionally, the bottom of the drive slot is provided with a pressure sensing component triggered by a pull plate, the pressure sensing component including an alarm for alerting personnel.

[0015] By adopting the above technical solution, the ring main unit achieves remote real-time alarm without the need for on-site personnel inspection. The operation and maintenance center can receive the signal through the alarm as soon as a fault occurs, which greatly shortens the fault response time and provides key information for quickly isolating faults and restoring power supply, thereby reducing economic losses. At the same time, it provides a final action confirmation signal. The pressure sensing component is triggered by the pull plate moving to the final position, which confirms the final state that "the pressure relief action has been successfully completed". This signal is accurate and reliable, and effectively avoids false alarms caused by malfunctions in intermediate links.

[0016] Optionally, a heat-conducting copper plate connected to the drive assembly is provided inside the mounting bracket, and the heat-conducting copper plate is located near the heat-generating electrical components.

[0017] By adopting the above technical solutions, a full-cycle safety protection system of "active + passive" was constructed, which improved the overall reliability and environmental adaptability of the equipment. At the same time, it accelerated heat conduction, shortened the delay from the occurrence of a fault to the triggering of the pressure relief device, which is conducive to containing the fault in the early stage when the energy is lower. It also improved the design flexibility, solved the possible contradiction between the temperature sensing position and the driving position, and optimized the overall layout.

[0018] Optionally, the surface of the flexible diaphragm can be fitted with the cabinet to form a breathing chamber, and the surface of the cabinet can be provided with breathing holes for the breathing chamber to inhale or exhale gas.

[0019] By adopting the above technical solution, daily dynamic pressure balance can be achieved, allowing the flexible diaphragm to "breathe" freely according to the pressure difference between the inside and outside of the cabinet, automatically adjusting the pressure of the airtight space inside the mounting frame, effectively preventing condensation caused by day and night temperature differences, protecting internal insulation, extending equipment life, and providing a channel for pressure compensation after a fault, ensuring that external air can enter smoothly, driving diaphragm deformation, thereby slowing down the formation of internal negative pressure.

[0020] Optionally, the cabinet surface is provided with a waterproof cover, inside which is a fragile thin sheet, and a sealing ring is fitted at the connection between the waterproof cover and the cabinet.

[0021] By adopting the above technical solutions, the waterproof cover and sealing ring work together to provide a high level of waterproof and dustproof sealing for the pressure relief channel, ensuring the normal operation of the ring main unit in harsh environments such as rain, snow, and sandstorms. The fragile thin sheet, as a replaceable disposable pressure relief membrane with a lower pressure threshold, can rupture and relieve pressure when the internal pressure rises abnormally but has not reached the shape memory alloy's action point, thus playing a preliminary protective role. Moreover, its rupture state can serve as an intuitive and low-cost diagnostic basis for maintenance personnel to judge the severity of internal faults.

[0022] Optionally, the overheat relief device also includes a manual reset assembly, which includes a handle for driving the gate or bolt back to the locked position.

[0023] By adopting the above technical solutions, the recoverability and maintainability of the device are ensured, maintenance costs and time are reduced, and equipment availability is improved. After the fault is resolved, maintenance personnel can use the operating handle to restore the device to the initial locked state, allowing the equipment to be quickly put back into operation, significantly reducing power outage time. Moreover, the reset operation must be performed manually on-site, and it is usually necessary to operate after confirming that the power is off and it is safe, which fundamentally avoids the potential risks that automatic reset may bring and complies with electrical safety operating procedures.

[0024] In summary, this application includes at least one of the following beneficial technical effects: 1. An active + passive full-cycle safety protection system has been constructed. The overheat relief device provides active safety intervention when a fault occurs, and the pressure balancing device provides passive protection under normal conditions and secondary protection after a fault, so as to achieve full life-cycle safety coverage of the ring main unit. 2. It produces a non-obvious synergistic effect, forming an organic whole between the two devices through "fluid connectivity". The pressure balancing device makes up for the defect of "risk of intrusion before reset" of the simple pressure relief device, thus achieving a technical synergistic effect. 3. It improves the overall reliability and environmental adaptability of the equipment, improves the internal microenvironment of the cabinet, reduces the probability of insulation failure caused by condensation and corrosion, and is suitable for harsh environments. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of this application; Figure 2 This is a cross-sectional structural diagram of the present application, mainly showing the pressure balancing device; Figure 3 This is a structural schematic diagram of the present application, mainly showing the mounting bracket; Figure 4 This is an exploded structural diagram of the present application, mainly showing the airtight groove; Figure 5 This is an exploded structural diagram of the present application, mainly showing the overheating pressure relief device; Figure 6 This is a cross-sectional structural schematic diagram of the present application, mainly showing the overheating pressure relief device; Figure 7 This is a structural schematic diagram of the present application, mainly showing the drive slot; Figure 8 This is a structural schematic diagram of the present application, mainly showing the transmission gear set; Figure 9 yes Figure 5 A magnified view of part A in the diagram.

[0026] Attached Figure Descriptions: 1. Cabinet; 2. Overheat Relief Device; 201. Mounting Base; 202. Gate; 203. Pull Plate; 204. Sliding Seat; 205. Drive Element; 206. Trigger Plate; 207. Thermal Conductive Copper Sheet; 208. Trigger Support Plate; 209. Pull Support Plate; 210. Large Gear; 211. Small Gear; 212. Brake Bolt; 213. Ratchet; 214. Drive Plate; 215. Pawl; 216. Metal Sheet; 3. Pressure Balancing Device; 301. Mounting bracket; 302, flexible diaphragm; 303, fragile sheet; 4, sealing door; 5, first sealing strip; 6, vent; 7, pressure relief channel; 8, airtight groove; 9, second sealing strip; 10, drive groove; 11, third sealing strip; 12, pressure sensor; 13, alarm; 14, control groove; 15, sliding groove; 16, locking groove; 17, first handle; 18, second handle; 19, clearance groove; 20, connecting ring; 21, waterproof cover; 22, sealing ring. Detailed Implementation

[0027] The following is in conjunction with the appendix Figure 1 - Appendix Figure 9 This application will be described in further detail below.

[0028] A high-security ring main unit, referring to Figure 1 , Figure 2The system includes a cabinet 1, an overheat relief device 2 installed inside the cabinet 1, and a pressure balancing device 3 installed inside the cabinet 1. The overheat relief device 2 releases pressure inside the cabinet 1 to prevent explosion in the event of an arcing phenomenon in the electrical components inside the cabinet 1. The pressure balancing device 3 regulates the pressure inside the cabinet 1 during normal operation and, after the overheat relief device 2 is triggered, compensates for the pressure difference between the inside and outside of the cabinet 1 through deformation. The overheat relief device 2 and the pressure balancing device 3 work together to provide full-cycle, multi-layered safety protection for the ring main unit.

[0029] A mounting bracket 301 is fixedly connected inside the cabinet 1. Electrical components such as busbars and switches are installed within the mounting bracket 301. A sealing door 4 is rotatably connected to the surface of the cabinet 1. The pressure balancing device 3 includes a flexible diaphragm 302 covering the outer surface of the mounting bracket 301, and the flexible diaphragm 302 has a certain elastic deformation capability. The edge of the flexible diaphragm 302 is tightly connected to the inner wall of the mounting bracket 301 via a first sealing strip 5. The flexible diaphragm 302, in conjunction with the sealing door 4, forms an airtight space inside the mounting bracket 301, encapsulating the electrical components. This airtight space is the location where the electrical components operate normally and where malfunctions occur. When the temperature or pressure within the airtight space changes slowly due to load variations, the flexible diaphragm 302 balances the internal and external pressure difference through slight deformation, preventing condensation.

[0030] A gap is provided between the mounting bracket 301 and the inner wall of the cabinet 1, which provides deformation space for the flexible diaphragm 302. At the same time, the inner wall of the cabinet 1, the flexible diaphragm 302, and the outer surface of the mounting bracket 301 cooperate to form a breathing chamber. A breathing hole 6 is opened on the surface of the cabinet 1 at the breathing chamber, allowing outside air to enter the breathing chamber through the breathing hole 6, thereby balancing the pressure in the airtight space.

[0031] Reference Figure 2 , Figure 3 , Figure 4 The upper surface of the cabinet 1 has several pre-set openings. The overheating pressure relief device 2 includes a mounting base 201 fixedly connected to the cabinet 1 at the pre-set openings. The bottom surface of the mounting base 201 is fixedly connected to the upper surface of the mounting frame 301 by bolts. The mounting base 201 has a pressure relief channel 7 that communicates with the airtight space inside the mounting frame 301. At the same time, the mounting base 201 has an airtight groove 8 at the end of the pressure relief channel 7 away from the mounting frame 301. A second sealing strip 9 is fixedly connected to the side wall of the airtight groove 8. A gate 202 is installed in the airtight groove 8. The side of the gate 202 abuts against the second sealing strip 9, thereby creating a new airtight space between the inside of the mounting frame 301 and the pressure relief channel 7.

[0032] Reference Figure 2 , Figure 4 , Figure 5The mounting base 201 has a drive groove 10 that communicates with the airtight groove 8 and the pressure relief channel 7. A third sealing strip 11 is fixedly connected to the inner wall of the drive groove 10. The third sealing strip 11 is connected to the second sealing strip 9 and abuts against the gate 202. The surface of the mounting base 201 at the point where the airtight groove 8 communicates with the drive groove 10 is chamfered, and the dimensions of the drive groove 10 match the gate 202. The gate 202 is connected to a pull plate 203 via a hinge. The pull plate 203 extends into the drive groove 10. When the pull plate 203 slides towards the bottom of the drive groove 10, the gate 202 can rotate towards the drive groove 10 using the surface of the mounting base 201 at the point where the airtight groove 8 communicates with the drive groove 10 as a fulcrum. When the pull plate 203 contacts the bottom of the drive groove 10, the gate 202 is fully opened and extends into the drive groove 10. In addition, a pressure sensor 12 is fixedly connected to the bottom of the drive groove 10. The pressure sensor 12 is connected to the alarm 13 via a signal. When the pull plate 203 contacts the bottom of the drive groove 10, the pressure sensor 12 can trigger the alarm 13 to alert the staff.

[0033] Reference Figure 3 , Figure 5 , Figure 6 A control slot 14 is provided within the mounting base 201, and the control slot 14 is positioned opposite the drive slot 10 on both sides of the pressure relief channel 7. Two sliding seats 204 are fixedly connected to the bottom of the control slot 14. Each sliding seat 204 contains a drive element 205 made of shape memory alloy, such as an SMA spring. Trigger plates 206 are fixedly connected to the ends of the two drive elements 205. Each sliding seat 204 has a sliding groove 15, with both ends of the trigger plate 206 extending into the sliding groove 15. The drive element 205 can control the sliding movement of the trigger plate 206 within the sliding groove 15. Additionally, a heat-conducting copper sheet 207 is fixedly connected to the sliding seat 204, extending into the mounting bracket 301 and fixedly connected near the heat-generating electrical component to ensure that the drive element 205 can be quickly triggered in case of an electrical component malfunction.

[0034] Reference Figure 5 , Figure 6 , Figure 7A trigger support plate 208 is fixedly connected to one side of the trigger plate 206, and a pull support plate 209 is fixedly connected to one side of the pull plate 203. The trigger support plate 208 is positioned above the pull support plate 209, and their projections coincide. When the drive element 205 contracts due to heat and the trigger plate 206 slides towards the bottom of the sliding groove 15, the trigger support plate 208 can push the pull support plate 209 and cause the pull plate 203 to slide towards the bottom of the drive groove 10. During this process, the two drive elements 205 control the sliding of the trigger plate 206 to ensure the driving force during the sliding of the trigger plate 206, thereby ensuring the movement of the gate 202 along the predetermined installation route.

[0035] Reference Figure 5 , Figure 6 , Figure 8 The mounting base 201 has a transmission gear set installed in the control groove 14, which includes a large gear 210 and a small gear 211 meshing with each other. Additionally, the mounting base 201 has a locking groove 16, which communicates with both the airtight groove 8 and the control groove 14. A bolt 212 is slidably connected within the locking groove 16, meshing with the small gear 211. The bolt 212 is used to drive the bolt 212 into or out of the airtight groove 8 when the small gear 211 rotates. The gate plate 202 has a snap-fit ​​groove that engages with the locking groove 16, allowing the small gear 211 to drive the bolt 212 into the snap-fit ​​groove and engage with the gate plate 202, fixing it to the airtight groove 8.

[0036] Reference Figure 8 , Figure 9 The large gear 210 is connected to a ratchet 213 via a connecting rod. The teeth on the ratchet 213 are inclined. Meanwhile, a drive plate 214 is fixedly connected to the side of the trigger plate 206 away from the trigger support plate 208. The drive plate 214 corresponds to the position of the ratchet 213. Several metal plates 216 are integrally formed on the side of the drive plate 214 facing the ratchet 213. The metal plates 216 are inclined downwards, and their inclination angle matches the inclination angle of the teeth on the ratchet 213. This allows the metal plates 216 to extend into the corresponding tooth grooves on the ratchet 213, enabling the drive plate 214 to mesh with the ratchet 213. When the trigger plate 206 controls the drive plate 214 to slide downwards, the metal piece 216 controls the ratchet 213 to rotate. When the trigger plate 206 controls the drive plate 214 to slide upwards, part of the surface of the metal piece 216 is pressed against the teeth of the ratchet 213, causing the metal piece 216 to deform towards the drive plate 214, and part of the metal piece 216 can extend out of the tooth groove of the ratchet 213, thereby disengaging the drive plate 214 from the ratchet 213. The engagement between the metal piece 216 on the drive plate 214 and the inclined ratchet 213 teeth ensures unidirectional drive and prevents uncertain movement of the mechanism during the reset process.

[0037] The mounting base 201 is rotatably connected to the pawl 215 within the control slot 14 via a rotating shaft, with the rotating shaft positioned in the middle of the pawl 215. One end of the pawl 215 is rotatably connected to the brake bolt 212, and the other end of the pawl 215 is fixedly connected to a locking block. The size of the locking block matches the tooth groove of the ratchet 213. When the brake bolt 212 is pushed out of the locking groove, the pawl 215 can rotate along the rotating shaft, causing the locking block to extend into the locking groove of the ratchet 213, thereby locking the ratchet 213.

[0038] Reference Figure 2 , Figure 6 The overheat relief device 2 also includes a manual reset assembly, which includes a first handle 17 fixedly connected to the gate plate 202 and a second handle 18 fixedly connected to the gate bolt 212. Meanwhile, the mounting base 201 has a clearance groove 19 communicating with the locking groove 16, allowing the second handle 18 to pass through the clearance groove 19 and extend beyond the mounting base 201. During reset, pulling the first handle 17 causes the gate plate 202 to re-abut against the second sealing strip 9 of the airtight groove 8, and pulling the second handle 18 upwards disengages the gate bolt 212 from the pinion 211. Pushing the second handle 18 then causes the gate bolt 212 to re-enter the locking groove, and during this process, the pawl 215 disengages from the ratchet 213.

[0039] Reference Figure 2 , Figure 3 The cabinet body 1 has an integrally formed connecting ring 20 on its surface. A waterproof cover 21 is threaded onto the connecting ring 20, covering the mounting base 201. The waterproof cover 21 has a curved exhaust pipe with a horizontally opening. A sealing ring 21 is provided in the gap between the waterproof cover 21 and the connecting ring 20. A mounting ring is threaded onto the opening of the waterproof cover 21, and a fragile sheet 303 is fixedly attached to the surface of the mounting ring. The cooperation between the sealing ring 21 and the fragile sheet 303 further ensures the airtightness of the cabinet body 1. When the overheat pressure relief device 2 is activated, the air pressure inside the cabinet body 1 will first enter the waterproof cover 21. At this time, the waterproof cover 21 increases the volume of the airtight space formed by the mounting bracket 301 and the pressure relief channel 7, effectively providing pressure reduction. If the air pressure generated inside the cabinet body 1 breaks through the fragile sheet 303, the fragile sheet 303 can reduce the impact of the air pressure being released to the outside.

[0040] The implementation principle of this application embodiment is as follows: The core working principle of the high-security ring network cabinet in this embodiment is to construct an integrated safety closed loop of "monitoring-response-mitigation" based on intelligent material drive and pure mechanical linkage.

[0041] Under normal conditions, the system maintains a stable internal environment through the pressure balancing device 3. The airtight space inside the mounting frame 301 is dynamically balanced by the flexible diaphragm 302 and the external breathing chamber. When the pressure in the airtight space fluctuates due to diurnal temperature differences or load changes, the flexible diaphragm 302 undergoes slight deformation, exchanging gas with the outside atmosphere through the breathing hole 6, effectively maintaining a slight positive pressure inside, preventing condensation, and protecting electrical components. At this time, the overheat relief device 2 is in standby mode: the gate 202 is mechanically locked by the gate bolt 212, and its airtightness is ensured by the second sealing strip 9 and the third sealing strip 11; the drive element 205, made of shape memory alloy, is in a pre-stretched state, and the entire transmission and locking system remains silent.

[0042] When an arcing or other fault occurs inside the cabinet, causing a sudden temperature rise, the system enters the fault response phase. Heat is rapidly transferred to the drive element 205 via the heat-conducting copper plate 207. When the temperature reaches its phase transition point, the drive element 205 contracts, generating a huge driving force that pulls the trigger plate 206 downwards. This downward movement simultaneously triggers two key processes: The pressure relief channel 7 opening process: The trigger plate 206, through its trigger support plate 208, abuts against the pull support plate 209 of the pull plate 203, forcing the pull plate 203 to slide towards the bottom of the drive groove 10. The movement of the pull plate 203 causes the gate plate 202 to rotate around its fulcrum, opening from the airtight groove 8 and providing a release path for the internal high-pressure gas and arc products.

[0043] Unlocking and Status Locking Process: The drive plate 214, which moves downward synchronously with the trigger plate 206, drives the ratchet 213 to rotate via its downward-sloping metal plate 216. The ratchet 213 converts the rotational motion into the linear backward motion of the brake 212 through a transmission gear set, causing it to disengage from the locking groove of the gate plate 202 and releasing the mechanical lock. Simultaneously, the backward-moving brake 212 pushes the pawl 215 to rotate, causing its end block to fall into the tooth groove of the ratchet 213, mechanically locking the entire mechanism in the trigger state. This locked state ensures that even if the fault is eliminated and the temperature drops, the pressure relief port remains open, providing maintenance personnel with a clear fault indication.

[0044] At the moment of and immediately after the pressure relief action, the system enters the aftereffect mitigation phase. The high-pressure gas is released instantaneously, effectively preventing the cabinet 1 from exploding. After the pressure relief, a negative pressure is formed in the airtight space. At this time, the pressure balancing device 3 immediately comes into play: the external atmospheric pressure acts on the flexible diaphragm 302 through the breather 6, causing it to indent inwards and actively compensate for the internal negative pressure. This greatly slows down the speed and flow of external humid and polluted air flowing back into the cabinet through the pressure relief port, forming a crucial secondary protection. Simultaneously, when the pull plate 203 moves to the bottom of the drive slot 10, it triggers the pressure sensing component, activating the alarm 13 for remote alarm activation.

[0045] In addition, the waterproof cover 21 and the fragile sheet 303 constitute the outermost physical protection and primary pressure relief channel 7, further enhancing environmental adaptability and safety.

[0046] After the fault is resolved, maintenance personnel can manually reset the components (operating the first handle 17 and the second handle 18) to disengage the pawl 215 from the ratchet 213, thereby resetting the brake bolt 212 and the gate 202 and re-establishing the airtight lock. After replacing the broken fragile sheet 303, the entire system can be restored to its initial standby state, ready to perform the next safety protection task.

[0047] In summary, this embodiment achieves "full-cycle, multi-level" safety protection for the ring main unit from normal operation, instantaneous fault impact to post-fault state through the deep coupling and synergistic effect of the overheat relief device 2 and the pressure balancing device 3 in terms of structure and function, which significantly improves the inherent safety level and operational reliability of the equipment.

[0048] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Identical components are represented by the same reference numerals. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application.

Claims

1. A high-security ring main unit, comprising a cabinet (1), characterized in that: The cabinet (1) includes an overheat relief device (2) and a pressure balancing device (3); The overheat relief device (2) includes: The mounting base (201) is set on a preset opening on the surface of the cabinet (1); A gate (202) is disposed on the mounting base (201) and a pull plate (203) is hinged thereto. The pull plate (203) is slidably disposed within the mounting base (201). A drive assembly, disposed within the mounting base (201), includes a drive element (205) made of shape memory alloy; When the temperature inside the cabinet (1) rises and triggers the drive element (205), the drive element (205) controls the pull plate (203) to slide and open the gate (202) to release the heat pressure inside the cabinet (1); The pressure balancing device (3) includes: Mounting bracket (301) is installed inside the cabinet (1) and is used to install electrical components; A flexible diaphragm (302) is disposed on the outer surface of the mounting frame (301), and it cooperates with the cabinet (1) and the heat relief device to form an airtight space inside the mounting frame (301); The overheat relief device (2) is in fluid communication with the pressure balancing device (3), and the flexible diaphragm (302) is configured to compensate for the pressure difference between the inside and outside of the box by deformation after the overheat relief device (2) is activated to relieve pressure.

2. The high-security ring main unit according to claim 1, characterized in that: The drive assembly includes a sliding seat (204) disposed on the surface of the mounting bracket (301), a trigger plate (206) is slidably disposed on the sliding seat (204), and the drive element (205) is disposed between the trigger plate (206) and the sliding seat (204); The mounting base (201) has a drive groove (10) inside, the pull plate (203) is slidably disposed in the drive groove (10), and the pull plate (203) is provided with a support plate that overlaps with the projection of the trigger plate (206); When the temperature rises, the drive element (205) controls the trigger plate (206) to slide in the sliding seat (204) and abut against the support plate of the pull plate (203). When the trigger plate (206) abuts against the support plate, it drives the pull plate (203) to slide towards the bottom of the drive groove (10), so that the gate plate (202) rotates along the mounting base (201) at the opening of the drive groove (10) and gradually extends into the drive groove (10).

3. A high-security ring main unit according to claim 2, characterized in that: The trigger plate (206) is provided with a drive plate (214), and the mounting base (201) is provided with a transmission gear set controlled by the drive plate (214). The transmission gear set is connected to a brake bolt (212). The brake bolt (212) extends into the gate plate (202) under normal conditions. When the trigger plate (206) slides and drives the transmission gear set to operate through the drive plate (214), the brake bolt (212) exits the gate plate (202).

4. A high-security ring main unit according to claim 3, characterized in that: The mounting base (201) is provided with a ratchet (213) and a pawl (215); the ratchet (213) is connected to the transmission gear set, and a number of metal plates (216) are inclined downward on the drive plate (214). The metal plates (216) extend into the corresponding grooves of the ratchet (213). When the temperature rises, the drive plate (214) controls the ratchet (213) to rotate through the metal plates (216), and causes the transmission gear set to run; the pawl (215) is rotatably connected to the brake (212). When the brake (212) exits the brake plate (202), the brake (212) pushes the pawl (215) to rotate, and causes the pawl (215) to extend into the grooves of the ratchet (213).

5. A high-security ring main unit according to claim 2, characterized in that: The bottom of the drive groove (10) is provided with a pressure sensing component triggered by a pull plate (203), and the pressure sensing component includes an alarm (13) for alerting staff.

6. A high-security ring main unit according to claim 1, characterized in that: The mounting bracket (301) is provided with a heat-conducting copper sheet (207) connected to the drive assembly, and the heat-conducting copper sheet (207) is located near the heat-generating electrical component.

7. A high-security ring main unit according to claim 1, characterized in that: The surface of the flexible diaphragm (302) cooperates with the cabinet (1) to form a breathing chamber, and the surface of the cabinet (1) is provided with a breathing hole (6) for the breathing chamber to inhale or exhale gas.

8. A high-security ring main unit according to claim 1, characterized in that: The cabinet (1) is provided with a waterproof cover (21), and a fragile thin sheet (303) is provided inside the waterproof cover (21). A sealing ring (21) is provided at the connection between the waterproof cover (21) and the cabinet (1).

9. A high-security ring main unit according to claim 1, characterized in that: The overheat relief device (2) also includes a manual reset component, which includes a handle for driving the gate (202) or the bolt (212) to reset to the locked position.

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