Normal pressure sealed air insulation ring network cabinet

Abstract

The application relates to the technical field of ring network cabinets, and discloses a normal-pressure sealed air insulation ring network cabinet, which comprises a gas tank chamber, an instrument chamber, a mechanism chamber and a cable chamber, the instrument chamber, the mechanism chamber and the cable chamber are sequentially arranged from top to bottom, the gas tank chamber is arranged at the back side of the mechanism chamber above the cable chamber, a normal-pressure device is arranged on the side of the gas tank chamber far from the mechanism chamber, a ventilation device is arranged on the top of the gas tank chamber, a plurality of side expansion sleeve pipes are arranged on the two sides of the top of the gas tank chamber, and a disconnecting switch is arranged below the side expansion sleeve pipes in the gas tank chamber. The disconnecting switch, a circuit breaker, a current transformer and a grounding switch and other electrical elements are packaged in the gas tank chamber and constitute a main conducting circuit, copper bars and copper pipes are selected in the main conducting circuit for circuit connection, the copper bars and the copper pipes have large surface area ratios and can stably supply current, the electric arc generated in the moment of closing and opening is relatively small and is insufficient to break through the electric field, so that insulation breakdown can be effectively prevented.

Description

Technical Field

[0001] This invention relates to the field of ring main unit technology, specifically a normal pressure sealed air-insulated ring main unit. Background Technology

[0002] Ring main units (RMS) are electrical devices that use high-voltage switchgear to form a ring network power supply unit. They are mainly used in substations or prefabricated substations in public buildings, industrial and mining enterprises, and residential communities. RMS units distribute electrical energy from the main power supply line to the outside via high-voltage switches, serving as crucial switching equipment for ring network and terminal power supply. Their short-circuit breaking capacity reaches the level of switchgear. To ensure reliable arc extinguishing, RMS units typically use sulfur hexafluoride (SF6) gas or solid insulating media. However, SF6 is a greenhouse gas, and leaks can harm the atmospheric environment. Furthermore, SF6 gas can transform into various harmful and corrosive gases during circuit breaker opening and closing and during arc discharge, affecting the equipment's service life.

[0003] Existing technologies employ environmentally friendly ring main units (RNBs) to avoid sulfur hexafluoride (SF6) gas pollution. These RNBs use air or nitrogen as the insulating medium. RNBs using air as the insulating medium are typically atmospheric pressure RNBs, where the internal pressure is the same as the external environment. When the internal temperature rises, outside air flows into the RNB. This air contains impurities such as dust and moisture. These impurities can cause air insulation failure, leading to insulation breakdown of electrical components such as disconnect switches during operation. This results in the RNB surface becoming electrified, posing a safety hazard. Therefore, this paper proposes an atmospheric pressure sealed air-insulated RNB that can isolate impurities from the outside air and prevent insulation breakdown. Summary of the Invention

[0004] The purpose of this invention is to provide a normal pressure sealed air-insulated ring main unit to solve the problems mentioned in the background art, such as air insulation failure caused by impurities in the outside air entering the ring main unit and insulation breakdown easily occurring inside the ring main unit.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] An atmospheric pressure sealed air-insulated ring main unit includes an air chamber, an instrument chamber, a mechanism chamber, and a cable chamber, arranged sequentially from top to bottom. The air chamber is located above the cable chamber, corresponding to the rear side of the mechanism chamber. An atmospheric pressure device is installed on the side of the air chamber away from the mechanism chamber. A ventilation device is installed on the top of the air chamber. Multiple side-expansion sleeves are installed on both sides of the top of the air chamber. A disconnecting switch is installed below the side-expansion sleeves in the air chamber. The side-expansion sleeves and the disconnecting switch are connected by a horizontal bar. A circuit breaker is installed on the side of the air chamber corresponding to the disconnecting switch below it. An outgoing bushing is installed below the side of the air chamber corresponding to the circuit breaker. The circuit breaker and the disconnecting switch are connected by a copper pipe. The circuit breaker and the outgoing bushing are also connected by a horizontal bar.

[0007] As a further aspect of the present invention: the air chamber includes a main frame and multiple sealing plates. The multiple sealing plates surround the main frame from top to bottom, front to back, left to right and right to form an internally hollow air chamber. The sealing plates and the main frame can be connected by bolts and a sealing ring is provided at the connection. After the sealing plates are connected to the main frame, they meet the requirements of insulation and airtightness.

[0008] As a further embodiment of the present invention: the sealing plate is a multi-layer composite plate, including iron mesh, nylon plate and plastic plate. The iron mesh is located in the middle position, and the nylon plate is attached and fixed on both sides. The plastic plate is fixed to the outer side of each of the two nylon plates. After multiple sealing plates are closed together, a sealed space is formed. The iron mesh in the sealing plate forms a Faraday cage after being closed, which has the function of electric field shielding. The nylon plate is used to enhance the overall structural strength of the sealing plate, and the plastic plate is used to further improve the insulation effect.

[0009] As a further embodiment of the present invention: the horizontal busbar is a flat copper busbar with an L-shaped longitudinal cross-section. The connection between the side expansion sleeve and the disconnecting switch is a rigid connection. The connection of the horizontal busbar is also a rigid connection to ensure the stability of the connection point and to provide a certain degree of shock and drop resistance. The joints of the horizontal busbar are not easily broken. The horizontal busbar has a large surface area ratio and strong heat dissipation capacity. The surface of the horizontal busbar is not coated with insulating material. The horizontal busbars are exposed in the gas chamber. The outlet end of the side expansion sleeve is connected to the upper end of the disconnecting switch through the horizontal busbar. The disconnecting switch is a three-position knife switch structure. The mechanism chamber is equipped with a corresponding disconnecting switch operating mechanism for operating the disconnecting switch. The disconnecting switch can be closed or opened through the disconnecting switch operating mechanism.

[0010] As a further embodiment of the present invention: the copper tube has a diameter of 20mm-40mm, the copper tube is made of solid material, the longitudinal cross-section of the copper tube is Z-shaped to enhance its heat dissipation performance, the two ends of the copper tube are respectively fixed to the lower end of the disconnecting switch and the input end of the circuit breaker, the outlet end of the outlet bushing extends to the cable chamber, and the side expansion bushing, the disconnecting switch, the circuit breaker, the outlet bushing and related connecting lines together constitute the main conductive circuit in the gas chamber.

[0011] As a further embodiment of the present invention: a current transformer is installed on one side of the gas chamber corresponding to the circuit breaker, and a grounding switch is installed below the current transformer in the gas chamber. The current transformer is electrically connected to the main conductive circuit and is used to monitor the current and voltage values ​​in the circuit and feed the data back to the instrument room, where it is displayed by the instruments. The secondary side of the current transformer is grounded and connected to the lower end of the grounding switch through its own S terminal. The grounding switch is also electrically connected to the main conductive circuit and can also be operated by the disconnecting switch operating mechanism. The grounding switch, the disconnecting switch, and the disconnecting switch operating mechanism are linked together.

[0012] As a further embodiment of the present invention: the atmospheric pressure device includes a housing, a first partition fixed at the middle position inside the housing, a second partition fixed at the front side of the housing corresponding to the first partition, a first cavity formed between the second partition and the inner wall of the front side of the housing, an ascending air passage structure provided in the first cavity, a second cavity formed between the first partition and the second partition, a descending air passage structure provided in the second cavity, a third cavity formed between the first partition and the inner wall of the rear side of the housing, a first filter screen fixedly engaged at the middle position in the third cavity, a notch provided at one corner of the bottom of the first partition, the second cavity and the third cavity connected through the notch, a pressurizing device installed on one side of the second cavity corresponding to the notch, an air inlet provided at the bottom of one side of the housing, the air inlet and the notch being located on the same side, multiple drainage holes provided on both inner walls of the housing corresponding to the second cavity, multiple air outlets provided on both inner walls of the housing corresponding to the third cavity, the air outlets being located behind the first filter screen.

[0013] As a further embodiment of the present invention: the rising air duct structure includes multiple first layered plates, the length of which is less than the length of the housing. These multiple first layered plates are staggered and arranged laterally within the first cavity. A first airflow channel is formed between adjacent first layered plates. A first airflow bend is reserved between one end of each first layered plate and one side wall of the housing. The multiple first airflow channels and the multiple first airflow bends cooperate to form a continuous, tortuous first airflow path. A first guiding ramp is provided above each of the multiple first layered plates. The inclination direction of the first guiding ramp is exactly opposite to the direction of airflow when it rises, and the end closer to the first airflow bend is higher. Inside the first cavity... The bottom of the first cavity is also provided with a first flow-guiding ramp. The lowest end of the first flow-guiding ramp at the bottom of the first cavity and the end between the adjacent first layer plate are set as the air inlet. The air inlet corresponds to the position of the air inlet. An overflow port is opened at one corner of the top of the second partition plate. The overflow port is located on the same side as the air inlet. Multiple first baffles are fixed at equal intervals at the bottom of multiple first layer plates. The distance between the bottom of the first baffle and the surface of the first flow-guiding ramp is denoted as D1. D1 decreases proportionally in the direction of air flow. The closer to the first airflow bend, the smaller the value of D1. The first baffle is made of ceramic material with a small coefficient of thermal expansion and a slow temperature change rate with the environment. The surface of the first baffle is smooth and dust does not easily adhere.

[0014] As a further embodiment of the present invention: the sinking air duct structure includes multiple second layered plates, the second layered plates having the same length as the first layered plates. These multiple second layered plates are staggered and arranged laterally within the second cavity, forming a second airflow channel between adjacent second layered plates. A second airflow bend is reserved between one end of each second layered plate and one side wall of the housing. The multiple second airflow channels and bends cooperate to form a continuous, tortuous second airflow path. A second flow-guiding ramp is provided above each of the multiple second layered plates, the inclination direction of which is perpendicular to the airflow path. The flow direction during descent is exactly opposite, with the end closer to the second airflow bend being higher. The second layer plate located at the bottom, the inner wall of the bottom of the box, and the first partition form an outflow channel. The notch is located at one end of the outflow channel, and the notch is far away from the nearest second airflow bend. Multiple second baffles are fixed at equal intervals on the top of multiple second layer plates. The distance between the bottom end of the second baffle and the surface of the second flow-guiding inclined platform is denoted as D2. D2 decreases proportionally in the direction of airflow, and the closer to the second airflow bend, the smaller the value of D2. The second baffle and the first baffle are made of the same material and have the same structure.

[0015] As a further embodiment of the present invention: the ventilation device includes a housing, a negative pressure suction device is installed inside the housing, an air inlet pipe is fixed to the bottom of the negative pressure suction device, and air outlet pipes are fixed to both sides of the negative pressure suction device. An air inlet window is opened at the bottom of the housing, the air inlet pipe passes through the air inlet window and is inserted into the air chamber, and a one-way valve is installed on the air inlet pipe. Air outlet windows are opened on both sides of the housing, and one end of each of the two air outlet pipes is fixed in the corresponding air outlet window. A second filter screen is installed on each of the two air outlet windows.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] In this invention, electrical components such as disconnect switches, circuit breakers, current transformers, and grounding switches are encapsulated in a gas chamber to form the main conductive circuit. The gas chamber adopts a structure of main frame and sealing plate. After the gas chamber is encapsulated, it forms a Faraday cage, which has the function of electric field shielding. The outer surface of the gas chamber will not be charged. Copper busbars and copper pipes are used for circuit connection in the main conductive circuit. Copper busbars and copper pipes have a large surface area ratio, which can stably supply current. The electric arc generated at the moment of closing and opening is relatively small and insufficient to break down the electric field, thereby effectively preventing insulation breakdown.

[0018] Furthermore, an atmospheric pressure device is installed on one side of the air chamber. The combination of the rising air passage structure and the sinking air passage structure in the atmospheric pressure device can form an airflow restriction structure. This structure can keep the air chamber at atmospheric pressure and allow the air chamber to be connected to the outside environment, but the outside air cannot enter the air chamber quickly. This can prevent a large amount of dust and water vapor in the outside air from entering the air chamber.

[0019] Furthermore, an air exchange device is installed at the top of the air chamber. This device, in conjunction with the atmospheric pressure device, can quickly refresh the air inside the air chamber, cool and dehumidify it, and maintain it at atmospheric pressure. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the structure of the present invention.

[0022] Figure 2 This is a schematic diagram of the air chamber in this invention.

[0023] Figure 3This is a structural separation diagram of the air chamber in this invention.

[0024] Figure 4 This is a schematic diagram of the internal structure of the air chamber.

[0025] Figure 5 This is a side view of the internal structure of the air chamber.

[0026] Figure 6 This is a schematic diagram of the sealing plate in the air chamber.

[0027] Figure 7 This is a schematic diagram of the atmospheric pressure device in this invention.

[0028] Figure 8 This is a structural separation diagram of the atmospheric pressure device in this invention.

[0029] Figure 9 This is a structural separation diagram of the air passage structure and the first partition in the atmospheric pressure device.

[0030] Figure 10 This is a plan view of the rising air passage structure in an atmospheric pressure device.

[0031] Figure 11 This is a plan view of the submerged air passage structure in an atmospheric pressure device.

[0032] Figure 12 This is a schematic diagram of the ventilation device in this invention.

[0033] Figure 13 This is a structural separation diagram of the ventilation device in this invention.

[0034] Figure Labels and Annotations: 1-Gas Box Chamber, 11-Main Frame, 12-Sealing Plate, 121-Iron Mesh, 122-Nylon Plate, 123-Plastic Plate, 13-Side Expansion Bushing, 14-Disconnecting Switch, 15-Circuit Breaker, 16-Outgoing Bushing, 17-Current Transformer, 18-Grounding Switch, 2-Instrument Chamber, 3-Mechanism Chamber, 4-Cable Chamber, 5-Atmospheric Pressure Device, 51-Box Body, 52-Air Inlet, 53-Air Outlet, 54-Drainage Hole, 55-First Baffle, 56-Second Baffle, 57-Rising Air Duct Structure, 571-First Layered Plate, 572- 573-First baffle, 574-Inlet end, 575-First airflow bend, 576-Flow port, 58-First filter screen, 59-Descending air passage structure, 591-Second layered plate, 592-Second flow ramp, 593-Second baffle, 594-Outlet channel, 595-Second airflow bend, 510-Pressure booster, 511-Notch, 6-Ventilation device, 61-Shell, 62-Second filter screen, 63-Negative pressure intake device, 64-Inlet pipe, 65-Outlet pipe, 66-Inlet window, 67-Outlet window. Detailed Implementation

[0035] The following embodiments will describe the present invention in detail with reference to the accompanying drawings. In the drawings or description, similar or identical parts are referred to by the same reference numerals, and in practical applications, the shape, thickness, or height of each component may be enlarged or reduced. The embodiments listed in this invention are merely illustrative and not intended to limit the scope of the invention. Any obvious modifications or changes made to this invention do not depart from the spirit and scope of the invention.

[0036] Please see Figures 1-5 In this embodiment of the invention, an atmospheric pressure sealed air-insulated ring main unit includes an air chamber 1, an instrument chamber 2, a mechanism chamber 3, and a cable chamber 4. The instrument chamber 2, mechanism chamber 3, and cable chamber 4 are arranged sequentially from top to bottom. The air chamber 1 is located above the cable chamber 4, corresponding to the rear side of the mechanism chamber 3. An atmospheric pressure device 5 is installed on the side of the air chamber 1 away from the mechanism chamber 3. An air exchange device 6 is installed on the top of the air chamber 1. The air chamber 1 includes a main frame 11 and multiple sealing plates 12. The multiple sealing plates 12 surround the main frame 11 from top to bottom, front to back, left to right, and right to form an internally hollow air chamber 1. The sealing plates 12 and the main frame 11 can be connected by bolts, and a sealing ring is provided at the connection.

[0037] After the sealing plate 12 is connected to the main frame 11, in the unsealed state (meaning that an installation gap is left, such as leaving the top or side of the air chamber 1 open), when performing insulation tests such as power frequency withstand voltage and lightning impulse withstand voltage on the air chamber 1, it is ensured that it can meet the requirements of the type test. In the sealed state, the air chamber 1 is evacuated and leak-tested using a dedicated balancing chamber device to ensure that the dynamic and static seals of its overall structure can meet the airtightness requirements.

[0038] Multiple side-expansion sleeves 13 are installed on both sides of the top of the gas chamber 1. A disconnecting switch 14 is installed below the side-expansion sleeves 13 in the gas chamber 1. The side-expansion sleeves 13 and the disconnecting switch 14 are connected by a horizontal busbar. The horizontal busbar is a flat copper busbar with an L-shaped longitudinal cross-section. The connection between the side-expansion sleeves 13 and the disconnecting switch 14 is a rigid connection. The conductive part of the connection uses a copper busbar. The rigid connection method and the use of copper busbar can ensure the stability of the connection point, have a certain shock and drop resistance, and the joint is not easy to break. The copper busbar is flat and has an L-shaped cross-section. The copper busbar has a large surface area ratio and excellent heat dissipation capacity. In actual installation, the copper busbar is directly exposed in the box without any external shielding. No insulating glue or other materials are applied to the surface of the copper busbar to further ensure its heat dissipation effect. It is suitable for medium and high voltage power transmission and transformation projects. In addition, due to the large surface area ratio of the copper busbar, the current supply is relatively stable, and the electric arc generated at the moment of closing and opening will also be relatively small.

[0039] External electrical wires are connected to the gas chamber 1 via a side expansion sleeve 13. The outlet end of the side expansion sleeve 13 is connected to the upper end of the disconnector switch 14 via a horizontal busbar. The disconnector switch 14 is a three-position knife switch structure. A disconnector switch operating mechanism for operating the disconnector switch 14 is installed in the mechanism chamber 3. The disconnector switch 14 can be closed or opened through the disconnector switch operating mechanism. A circuit breaker 15 is installed on the side below the disconnector switch 14 in the gas chamber 1. An outlet sleeve 16 is installed below the side of the circuit breaker 15 in the gas chamber 1. The circuit breaker 15 and the disconnector switch 14 are connected by a copper pipe with a diameter of 20 mm. The copper tube is 40mm thick and solid. The longitudinal cross-section of the copper tube is Z-shaped to enhance its heat dissipation performance. The two ends of the copper tube are fixed to the lower end of the disconnecting switch 14 and the input end of the circuit breaker 15, respectively. The circuit breaker 15 and the outgoing bushing 16 are also connected by a horizontal bar. The connection method is also a hard connection. The two ends of the horizontal bar are fixed to the output end of the circuit breaker 15 and the inlet end of the outgoing bushing 16, respectively. The outgoing end of the outgoing bushing 16 extends into the cable compartment 4. The side expansion bushing 13, disconnecting switch 14, circuit breaker 15, outgoing bushing 16 and related connecting lines together constitute the main conductive circuit in the gas chamber 1.

[0040] A current transformer 17 is installed on one side of the circuit breaker 15 inside the gas chamber 1. A grounding switch 18 is installed below the current transformer 17 inside the gas chamber 1. The current transformer 17 is electrically connected to the main conductive circuit and is used to monitor the current and voltage values ​​in the circuit, feeding the data back to the instrument room 2 for display by the instruments in the instrument room 2. The secondary side of the current transformer 17 is grounded and connected to the lower end of the grounding switch 18 through its S2 terminal. The grounding switch 18 is also electrically connected to the main conductive circuit. Simultaneously, the grounding switch 1... 8 can also be operated by the disconnector switch operating mechanism. The grounding switch 18, disconnector switch 14 and disconnector switch operating mechanism are linked together. When the line where the circuit breaker 15 is located (i.e. the main conductive circuit) needs to be repaired, the circuit breaker 15 is in the open position, and the disconnector switches 14 above are all open and in the open state. At this time, the grounding switch 18 is closed for normal grounding to ensure the safety of equipment and maintenance personnel. Temperature and humidity sensors and air pressure sensors are also installed in the gas box chamber 1 to monitor the temperature, humidity and air pressure changes in the gas box chamber.

[0041] Please see Figure 6The sealing plate 12 is a multi-layer composite plate, including an iron mesh 121, a nylon plate 122, and a plastic plate 123. The iron mesh 121 is located in the middle, and the nylon plates 122 are attached and fixed on both sides. The plastic plates 123 are fixed to the outer sides of the two nylon plates 122. After multiple sealing plates 12 are enclosed, a sealed space is formed. The iron mesh 121 in the sealing plate 12 forms a Faraday cage, which has the function of electric field shielding. The electric arc generated by the disconnecting switch 14 and the grounding switch 18 at the moment of closing and opening will be confined in the cage. Due to the unique wire connection method in the main conductive circuit, the generated electric arc is relatively small and insufficient to break down the electric field, thus effectively preventing insulation breakdown. The nylon plate is set to enhance the overall structural strength of the sealing plate. The plastic plate is set on the outer side of the nylon plate to further improve the insulation effect. The surface of the gas chamber will not be electrified, ensuring safe use.

[0042] Please see Figures 7-9 The atmospheric pressure device 5 includes a box 51, which is a hollow box structure formed by multiple plates. The material and structure of the plates are the same as those of the sealing plate 12. The multiple plates can be connected by bolts or by a slot and buckle structure. After connection, a sealing ring is set at the joint to ensure that the airtightness of the box meets the usage requirements. A first partition 55 is fixed in the middle position inside the box 51, and a second partition 56 is fixed in front of the first partition 55 inside the box 51.

[0043] A first cavity is formed between the second partition 56 and the inner wall of the front side of the box 1. An upward air passage structure 57 is provided in the first cavity. A second cavity is formed between the first partition 55 and the second partition 56. A downward air passage structure 59 is provided in the second cavity. A third cavity is formed between the first partition 55 and the inner wall of the rear side of the box 1. A first filter screen 58 is snapped and fixed in the middle position of the third cavity.

[0044] A notch 511 is provided at one corner of the bottom of the first partition 55. The second cavity and the third cavity are connected by the notch 511. A pressurizing device 510 is installed on one side of the second cavity corresponding to the notch 511. The pressurizing device 510 is an existing air pump device used to accelerate the air in the second cavity into the third cavity. An air inlet 52 is provided at the bottom of one side of the box body 1. The air inlet 52 is located on the same side as the notch 511. Multiple drain holes 54 are provided on both sides of the inner wall of the box body 1 corresponding to the second cavity. Multiple air outlets 53 are provided on both sides of the inner wall of the box body 1 corresponding to the third cavity. The air outlets 53 are located behind the first filter screen 58.

[0045] Please see Figures 10-11The rising air duct structure 57 includes multiple first layered plates 571, the length of which is less than the length of the housing 51. The multiple first layered plates 571 are staggered and arranged laterally within the first cavity. A first airflow channel is formed between two adjacent first layered plates 571. A first airflow bend 575 is reserved between one end of each first layered plate 571 and one side wall of the housing 51. Air in the lower first airflow channel flows into the upper first airflow channel through the first airflow bend 575 (the airflow direction during ascent is as follows). Figure 10 As indicated by the middle arrow, multiple first airflow channels and multiple first airflow bends 575 cooperate with each other to form a continuous and tortuous first airflow path;

[0046] A first flow-guiding ramp 572 is provided above each of the multiple first layer plates 571. The inclination direction of the first flow-guiding ramp 572 is exactly opposite to the flow direction of the air when it rises. The end closer to the first airflow bend 575 is higher. A first flow-guiding ramp 572 is also provided at the bottom of the first cavity. The lowest end of the first flow-guiding ramp 572 at the bottom of the first cavity and the end between it and the adjacent first layer plate 571 are set as the air inlet end 574. The air inlet end 574 corresponds to the position of the air inlet 52. An overflow port 576 is opened at one corner of the top of the second partition plate 56. The overflow port 576 and the air inlet end 574 are located on the same side. External air flows into the airflow channel through the air inlet end 574, passes through multiple tortuous airflow paths, and finally flows into the second cavity through the overflow port 576.

[0047] Multiple first baffles 573 are fixed at equal intervals at the bottom of multiple first layer plates 571. The distance between the bottom of the first baffle 573 and the surface of the first airflow ramp 572 is denoted as D1. D1 decreases proportionally in the direction of airflow. The closer to the first airflow bend 575, the smaller the value of D1. The first baffle 573 is made of ceramic material with a small coefficient of thermal expansion and a slow temperature change with the environment. The surface of the first baffle 573 is smooth, and dust does not easily adhere to it. The temperature inside the ring main unit will not be conducted to the first baffle 573. The temperature of the first baffle 573 is lower than that of the external environment. When the water vapor in the air comes into contact with the first baffle 573, condensation will be generated. The condensation flows along the first airflow ramp 572 and is finally discharged from the air inlet 52. In the process of flowing, it will carry away the dust attached to the inner wall.

[0048] The descending air duct structure 59 includes multiple second-layer plates 591, each with the same length as the first-layer plate 571. These second-layer plates 591 are staggered and arranged laterally within the second cavity. A second airflow channel is formed between adjacent second-layer plates 591. A second airflow bend 595 is pre-reserved between one end of each second-layer plate 591 and a side wall of the housing 51. Air in the upper second airflow channel flows into the lower second airflow channel through the second airflow bend 595 (the airflow direction during descent is as follows). Figure 11 As shown by the middle arrow), multiple second airflow channels and multiple second airflow bends 595 cooperate with each other to form a continuous and tortuous second airflow path;

[0049] Above each of the multiple second-layer plates 591, there is a second flow-guiding ramp 592. The inclination direction of the second flow-guiding ramp 592 is exactly opposite to the flow direction when the air sinks. The end closer to the second airflow bend 595 is higher. The second layer plate 591 located at the bottom, the inner wall of the bottom of the box 51, and the first partition 55 form an outflow channel 594. The notch 511 is located at one end of the outflow channel 594 and is far away from the nearest second airflow bend 595. The air in the first cavity flows into the second cavity through the flow port 576, flows into the outflow channel 594 after passing through multiple tortuous second airflow passages, and finally flows into the third cavity through the notch 511.

[0050] Multiple second baffles 593 are fixed at equal intervals on the top of multiple second layer plates 591. The distance between the bottom of the second baffle 593 and the surface of the second flow-guiding ramp 592 is denoted as D2. D2 decreases proportionally in the direction of air flow. The closer to the second airflow bend 595, the smaller the value of D2. The second baffle 593 has the same material and structure as the first baffle 573 and also plays a condensation role. Multiple drain holes 54 are respectively set on one side near the lowest end of the second flow-guiding ramp 592. The condensate flows along the platform and finally flows out through the drain holes 54. A one-way valve is installed in each of the multiple drain holes 54.

[0051] In this embodiment, external air first enters the first cavity. Under the action of the rising air passage structure 57, the air flows upward. Through the combined use of multiple first baffles 573 and multiple first guide ramps 572, the blocking area is gradually increased to block the air, gradually dissipating the air energy. The air flow rate slows down, the water vapor in the air loses energy and is intercepted and condensed by the first baffles 573, and the dust in the air loses energy and is deposited downward on the first guide ramps 572. The air is initially filtered, and the condensed water carries the dust outward.

[0052] After initial filtration, the air flows into the second cavity through the outlet 576. Under the action of the downward air passage structure 59, the air flows downward and is blocked again by the combined use of multiple second baffles 593 and multiple second guide ramps 592, with the blocking area gradually increasing. The air energy is gradually dissipated, the air flow rate is further slowed down, the water vapor in the air loses energy and is intercepted and condensed by the second baffles 593, and the dust in the air loses energy and is deposited downward on the second guide ramps 592. The air is filtered a second time. At this time, the air is relatively clean, and the content of water vapor and dust in the air is extremely low, so it will not affect the movement of electrical components in the air chamber 1.

[0053] Under natural conditions, air flows upwards, but in the downward air duct structure 59, the airflow is downwards. Without external force, the air can only fill the airflow channel and cannot pass through the channel quickly. The airflow speed is slow, and the air enters the air chamber 1 along the channel, keeping the air chamber 1 at normal pressure. The combined use of the rising air duct structure 57 and the downward air duct structure 59 can form an airflow restriction structure. This structure can keep the air chamber 1 at normal pressure, allowing the air chamber 1 to remain connected to the external environment, but preventing external air from quickly entering the air chamber 1. This can prevent a large amount of dust and moisture from entering the air chamber 1. When the temperature and air pressure inside the air chamber 1 change, the pressurization device 510 can quickly refresh the indoor air to maintain normal pressure.

[0054] Please see Figures 12-13 The ventilation device 6 includes a housing 61, which is a hollow shell structure formed by multiple plates. The material and structure of the plates are the same as those of the sealing plate 12. A negative pressure suction device 63 is installed inside the housing 61. The negative pressure suction device 63 can be a fan or an air pump, which is used to extract the air in the air chamber 1 outward. An air inlet pipe 64 is fixed at the bottom of the negative pressure suction device 63, and air outlet pipes 65 are fixed on both sides of the negative pressure suction device 63.

[0055] An air inlet window 66 is provided at the bottom of the housing 61. An air inlet pipe 64 passes through the air inlet window 66 and is inserted into the air chamber 1. A one-way valve is installed on the air inlet pipe 64. Air outlet windows 67 are provided on both sides of the housing 61. One end of each of the two air outlet pipes 65 is fixed in the corresponding air outlet window 67. A second filter screen 62 is installed on each of the two air outlet windows 67. When the temperature and humidity in the air chamber 1 are high, the air inside can be drawn out by the negative pressure suction device 63. In conjunction with the pressurization device 510, the air in the air chamber 1 can be quickly refreshed, the air in the air chamber 1 can be cooled and dehumidified, and the air chamber 1 can be kept at normal pressure.

[0056] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0057] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A normal pressure sealed air-insulated ring main unit, comprising an air chamber (1), an instrument chamber (2), a mechanism chamber (3), and a cable chamber (4), wherein the instrument chamber (2), the mechanism chamber (3), and the cable chamber (4) are arranged sequentially from top to bottom, and the air chamber (1) is located above the cable chamber (4) corresponding to the rear side of the mechanism chamber (3), characterized in that, An atmospheric pressure device (5) is installed on the side of the gas chamber (1) away from the mechanism chamber (3). An air exchange device (6) is installed on the top of the gas chamber (1). Multiple side expansion sleeves (13) are installed on both sides of the top of the gas chamber (1). A disconnecting switch (14) is installed in the gas chamber (1) below the side expansion sleeves (13). The side expansion sleeves (13) and the disconnecting switch (14) are connected by a horizontal row. A circuit breaker (15) is installed in the gas chamber (1) on the side below the disconnecting switch (14). A line outlet sleeve (16) is installed in the gas chamber (1) below the side of the circuit breaker (15). The circuit breaker (15) and the disconnecting switch (14) are connected by a copper pipe. The circuit breaker (15) and the line outlet sleeve (16) are also connected by a horizontal row. The atmospheric pressure device (5) includes a housing (51). A first partition (55) is fixed in the middle of the housing (51). A second partition (56) is fixed in the housing (51) on the front side corresponding to the first partition (55). A first cavity is formed between the second partition (56) and the inner wall of the front side of the housing (51). An ascending air passage structure (57) is provided in the first cavity. A second cavity is formed between the first partition (55) and the second partition (56). A descending air passage structure (59) is provided in the second cavity. A third cavity is formed between the first partition (55) and the inner wall of the rear side of the housing (51). A first filter screen (55) is snapped and fixed in the middle of the third cavity. 8) A notch (511) is provided at one corner of the bottom of the first partition (55). The second cavity and the third cavity are connected through the notch (511). A pressurizing device (510) is installed on one side of the second cavity corresponding to the notch (511). An air inlet (52) is provided at the bottom of one side of the box (51). The air inlet (52) and the notch (511) are located on the same side. Multiple drainage holes (54) are provided on both sides of the inner wall of the box (51) corresponding to the second cavity. Multiple air outlets (53) are provided on both sides of the inner wall of the box (51) corresponding to the third cavity. The air outlets (53) are located behind the first filter (58).

2. The atmospheric pressure sealed air-insulated ring main unit according to claim 1, characterized in that, The air chamber (1) includes a main frame (11) and multiple sealing plates (12). The multiple sealing plates (12) surround the main frame (11) from top to bottom, front to back, left to right and right to form an internally hollow air chamber (1). The sealing plates (12) and the main frame (11) can be connected by bolts and a sealing ring is provided at the connection. After the sealing plates (12) are connected to the main frame (11), they meet the requirements of insulation and airtightness.

3. The atmospheric pressure sealed air-insulated ring main unit according to claim 2, characterized in that, The sealing plate (12) is a multi-layer composite plate, including iron mesh (121), nylon plate (122) and plastic plate (123). The iron mesh (121) is located in the middle position, and the nylon plate (122) is attached and fixed on both sides. The plastic plate (123) is fixed to the outer side of the two nylon plates (122). After the multiple sealing plates (12) are enclosed, they form a closed space. The iron mesh (121) in the sealing plate (12) forms a Faraday cage after being enclosed, which has the function of electric field shielding. The nylon plate (122) is used to enhance the overall structural strength of the sealing plate (12), and the plastic plate (123) is used to further improve the insulation effect.

4. The atmospheric pressure sealed air-insulated ring main unit according to claim 1, characterized in that, The horizontal busbar is a flat copper busbar with an L-shaped longitudinal cross-section. The connection between the side expansion sleeve (13) and the disconnector switch (14) is a hard connection. The connection of the horizontal busbar is a hard connection to ensure the stability of the connection point and to have a certain shock and drop resistance. The joint of the horizontal busbar is not easy to break. The horizontal busbar has a large surface area ratio and strong heat dissipation capacity. The surface of the horizontal busbar is not coated with insulating material. The horizontal busbar is exposed in the air box chamber (1). The outlet end of the side expansion sleeve (13) is connected to the upper end of the disconnector switch (14) through the horizontal busbar. The disconnector switch (14) is a three-position knife switch structure. The mechanism chamber (3) is equipped with a disconnector switch operating mechanism for operating the disconnector switch (14). The disconnector switch (14) can be closed or opened through the disconnector switch operating mechanism.

5. The atmospheric pressure sealed air-insulated ring main unit according to claim 4, characterized in that, The copper tube has a diameter of 20mm-40mm and is made of solid material. The longitudinal cross-section of the copper tube is Z-shaped to enhance its heat dissipation performance. The two ends of the copper tube are respectively fixed to the lower end of the disconnect switch (14) and the input end of the circuit breaker (15). The outlet end of the outlet bushing (16) extends into the cable chamber (4). The side expansion bushing (13), the disconnect switch (14), the circuit breaker (15), the outlet bushing (16), and the related connecting lines together constitute the main conductive circuit in the gas chamber (1).

6. The atmospheric pressure sealed air-insulated ring main unit according to claim 5, characterized in that, A current transformer (17) is installed in the gas chamber (1) on one side corresponding to the circuit breaker (15). A grounding switch (18) is installed in the gas chamber (1) below the current transformer (17). The current transformer (17) is electrically connected to the main conductive circuit and is used to monitor the current and voltage values ​​in the circuit and feed the data back to the instrument room (2), which is then displayed by the instrument in the instrument room (2). The secondary side of the current transformer (17) is grounded and connected to the lower end of the grounding switch (18) through its own S2 terminal. The grounding switch (18) is also electrically connected to the main conductive circuit, and the grounding switch (18) can also be operated by the disconnecting switch operating mechanism. The grounding switch (18), the disconnecting switch (14), and the disconnecting switch operating mechanism are linked together.

7. The atmospheric pressure sealed air-insulated ring main unit according to claim 6, characterized in that, The rising air passage structure (57) includes multiple first layered plates (571), the length of which is less than the length of the box (51). The multiple first layered plates (571) are staggered and arranged laterally in the first cavity. A first airflow channel is formed between two adjacent first layered plates (571). A first airflow bend (575) is reserved between one end of each first layered plate (571) and one side wall of the box (51). The multiple first airflow channels and the multiple first airflow bends (575) cooperate to form a continuous and tortuous first airflow path. A first flow-guiding ramp (572) is provided above each of the multiple first layered plates (571). The inclination direction of the first flow-guiding ramp (572) is exactly opposite to the flow direction of the rising air. The end closer to the first airflow bend (575) is higher. A first flow-guiding ramp is also provided at the bottom of the first cavity. 572), the lowest end of the first flow-guiding ramp (572) at the bottom of the first cavity is set as an air inlet (574) between the lowest end of the first flow-guiding ramp (572) and the adjacent first layer plate (571). The air inlet (574) corresponds to the position of the air inlet (52). An overflow port (576) is opened at one corner of the top of the second partition plate (56). The overflow port (576) and the air inlet (574) are located on the same side. Multiple first baffles (573) are fixed at equal intervals at the bottom of multiple first layer plates (571). The distance between the bottom end of the first baffle (573) and the surface of the first flow-guiding ramp (572) is denoted as D1. D1 decreases proportionally in the direction of air flow. The closer to the first airflow bend (575), the smaller the value of D1. The first baffle (573) is made of ceramic material with a small coefficient of thermal expansion and a slow temperature change with the environment. The surface of the first baffle (573) is smooth and dust does not easily adhere.

8. The atmospheric pressure sealed air-insulated ring main unit according to claim 7, characterized in that, The descending air duct structure (59) includes multiple second layered plates (591), each with the same length as the first layered plate (571). These plates are staggered and arranged laterally within the second cavity. A second airflow channel is formed between adjacent plates. A second airflow bend (595) is reserved between one end of each second layered plate (591) and a side wall of the housing (51). These multiple second airflow channels and bends (595) cooperate to form a continuous, tortuous second airflow path. A second flow-guiding ramp (592) is provided above each of the second layered plates (591). The inclination direction of the second flow-guiding ramp (592) is exactly opposite to the direction of airflow during descent. The end closer to the second airflow bend (595) is higher. The second layer plate (591) located at the bottom, together with the inner wall of the bottom of the box (51) and the first partition plate (55), forms an outflow channel (594). The notch (511) is located at one end of the outflow channel (594) and the notch (511) is far away from the nearest second airflow bend (595). Multiple second baffles (593) are fixed at equal intervals on the top of multiple second layer plates (591). The distance between the bottom end of the second baffle (593) and the surface of the second flow-guiding ramp (592) is denoted as D2. D2 decreases proportionally in the direction of airflow. The closer to the second airflow bend (595), the smaller the value of D2. The second baffle (593) and the first baffle (573) are made of the same material and have the same structure.

9. The atmospheric pressure sealed air-insulated ring main unit according to claim 1, characterized in that, The ventilation device (6) includes a housing (61), inside which a negative pressure suction device (63) is installed. An air inlet pipe (64) is fixed at the bottom of the negative pressure suction device (63), and air outlet pipes (65) are fixed on both sides of the negative pressure suction device (63). An air inlet window (66) is opened at the bottom of the housing (61). The air inlet pipe (64) passes through the air inlet window (66) and is inserted into the air chamber (1). A one-way valve is installed on the air inlet pipe (64). Air outlet windows (67) are opened on both sides of the housing (61). One end of each of the two air outlet pipes (65) is fixed in the corresponding air outlet window (67). A second filter screen (62) is installed on each of the two air outlet windows (67).

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