Voltage transformer chamber of ring main unit

Abstract

The invention discloses a ring main unit voltage transformer chamber which comprises a voltage transformer compartment which is arranged on the periphery of a voltage transformer body and forms an integral welding structure with a switch gas box and a mechanism chamber; the cabinet door is of a closed detachable structure and is installed outside the voltage transformer compartment, the cabinet door comprises an integrated frame and a panel connected with the frame in a sealed mode through a fastener, an elastic sealing layer is arranged between the panel and the frame, and the elastic sealing layer is arranged between the panel and the frame. The welding seam of the cabinet door and the voltage transformer compartment is processed through a continuous sealing process. Through the secondary sealing structural design of the closed detachable door and the PT compartment, IP68-level waterproof protection is achieved, the problems of deformation and water seepage of a traditional single door and corrosion of a mechanical lock are solved, non-contact monitoring and convenient maintenance are considered, the operation reliability of equipment in a complex environment is remarkably improved, and the service life of the equipment in the complex environment is remarkably prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution equipment, and particularly to a potential transformer room of a ring main unit (RMU). Background Art

[0002] In the power system, the potential transformer (PT) room in the RMU serves as an independent functional space, integrating and installing potential transformers and related equipment, and undertaking key functions such as voltage measurement, monitoring, and protection. However, the operating environment of the PT room is usually relatively complex, facing challenges such as humid and rainy climates and corrosion by corrosive gases for a long time. Its waterproof performance is directly related to the safety and reliability of equipment operation. Once the waterproofing fails and external dust and moisture invade the interior of the cabinet, it is extremely easy to cause equipment operation failures, and in severe cases, even lead to power system accidents.

[0003] The existing design schemes for the water-immersion-proof PT room of the RMU mainly focus on optimizing the cabinet door structure and improving the sealing performance. In terms of the cabinet door design, a single-opening embedded structure is generally adopted. By tightly fitting the cabinet door with the cabinet frame, the gaps are reduced, and a multi-point mechanical lock is configured to ensure uniform force when the cabinet door is closed, enhancing the compression effect of the sealing strip. In terms of the sealing design, materials with high elasticity, aging resistance, and excellent weather resistance, such as EPDM rubber and fluororubber, are selected, and "P"-type or "E"-type sealing strips are used to seal the gaps between the cabinet door and the cabinet body in multiple directions, blocking the path of water intrusion. For example, a sealed PT room of a certain RMU places the PT independently in a sealed box, realizes the primary connection with the gas tank through a bushing assembly, and adds sealing rings and rubber gaskets in the bushing assembly, so that the protection level reaches IP54, effectively improving the insulation performance and reliability of the PT.

[0004] Although the above technical solutions have improved the waterproof performance of the PT room to a certain extent, there are still technical bottlenecks to be solved in the existing design of the PT room of the RMU. On the one hand, due to the limitations of processing accuracy and deformation during long-term use, the single-layer door structure is difficult to completely eliminate tiny gaps. Under extreme working conditions such as heavy rainfall and water accumulation, water is still likely to seep in through the gaps. On the other hand, although the traditional mechanical lock opening and closing device is convenient to operate, it is prone to rust in a harsh environment, and its complex mechanical structure cannot guarantee the long-term waterproof sealing at the switch, resulting in a significant decline in waterproof performance over time. Therefore, how to further improve the waterproof sealing performance of the PT room of the RMU while taking into account practicality has become a technical problem that urgently needs to be solved at present. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a potential transformer room of a ring main unit to further improve the water-immersion-proof ability so that it can operate for a long time in a more complex operating environment.

[0006] To solve the above technical problems, the present invention provides a voltage transformer compartment for a ring main unit, comprising:

[0007] A voltage transformer compartment, arranged around the voltage transformer body and forming an integral welded structure with the switch gas tank and the mechanism compartment;

[0008] A cabinet door, adopting a closed and detachable structure, installed outside the voltage transformer compartment. The cabinet door includes an integrated frame and a panel hermetically connected to the frame by fasteners. An elastic sealing layer is provided between the panel and the frame, and the welded joint between the cabinet door and the voltage transformer compartment is treated by a continuous sealing process.

[0009] Preferably, an infrared temperature measurement window is provided at the upper part of the cabinet door. The temperature measurement area adopts a metal mesh heat conduction structure. The infrared temperature measurement window is used for an infrared temperature gun to test the temperature of the internal cable head without opening the cabinet door.

[0010] Preferably, temperature measurement window baffles inclined downward are arranged on both the upper and lower sides of the infrared temperature measurement window, which are used to guide the ventilation direction and adjust the ventilation flow rate.

[0011] Preferably, the frame and the panel are made of 304 stainless steel. The elastic sealing layer is a silicone rubber sealing strip with a hardness of 60-65 Shore A and an elongation at break of ≥300%.

[0012] Preferably, the continuous sealing process includes using V-groove welding with a groove angle of 65-70°, a root face size of 0-0.5 mm, controlling the interpass temperature during welding at ≤150°C, and implementing all-position welding using argon shielded welding.

[0013] Preferably, the process parameters of the argon shielded welding include: welding current 25-150 A, arc voltage 6-20 V, argon flow rate 8-15 L / min, tungsten electrode diameter 1.6-2.4 mm, and welding speed 8-25 cm / min.

[0014] Preferably, the voltage transformer compartment has a stainless steel cover plate, and an observation window is also provided on the stainless steel cover plate.

[0015] Preferably, the observation window is made of tempered glass. The outer surface is bonded to the sealing panel by waterproof glass glue, and an annular steel pressing strip is provided on the inner surface. A silicone rubber buffer layer is filled between the annular steel pressing strip and the sealing panel.

[0016] Preferably, the silicone rubber sealing strip between the panel and the frame is of a "P" type or "E" type structure, and an interference fit is formed by tightening with bolts.

[0017] Preferably, the welding methods for the voltage transformer compartment include butt welding, fillet welding or lap welding. The joint gap for butt welding is controlled within 0 - 0.5 mm, and the lap length for lap welding is not less than 5 times the thickness of the thinner sheet. High-frequency arc striking is used and the molten pool is filled during arc extinguishing. The rocking method is used for flat welding, and the mop method is used for all-position welding.

[0018] Implementing the present invention has the following beneficial effects: Through the innovative design of the enclosed removable door and the secondary sealing of the PT compartment, the waterproof performance and operation reliability of the voltage transformer compartment in the ring main unit are significantly improved. The cabinet door adopts an integrally welded frame of high-strength 304 stainless steel, combined with a bolt-fastening sealing structure of a stainless steel baffle and a silicone rubber sealing strip, completely eliminating the problem of water seepage through gaps caused by processing accuracy or long-term deformation of the traditional single-opening door, and can block the intrusion of rainwater, moisture and corrosive gases in a continuous immersion environment. The PT compartment, the switch gas tank and the mechanism room form a secondary sealed space without splicing gaps through integral welding. The design of its front-sealed stainless steel cover plate and high-strength glass observation window can still provide an independent protection area for the voltage transformer body even when accidental water seepage occurs in other parts of the cabinet, ensuring the stable operation of core functions such as voltage measurement and protection in complex environments such as humidity and rain.

[0019] In terms of operation convenience and maintenance efficiency, the present invention takes into account both the sealing requirements and the maintenance convenience. The infrared temperature measurement window at the lower part of the cabinet door and the high-strength glass observation window on the front of the PT compartment allow the staff to detect the temperature of the cable head with an infrared temperature gun and directly visually observe the state of the PT joint without opening the cabinet door or disassembling the sealing structure, avoiding the attenuation of the sealing performance caused by frequent door opening and closing. The detachable cabinet door and compartment design adopt a standardized bolt-fastening structure, reserving a reasonable installation and maintenance space, which can be quickly disassembled and reset during equipment maintenance. Combined with the interference fit sealing of the silicone rubber sealing strip, it not only ensures the high efficiency of maintenance operations but also avoids the problem of opening and closing failure caused by rust of the traditional mechanical lock structure, significantly improving the operation and maintenance convenience.

[0020] In terms of structural design, the integrally welded frame made of 304 stainless steel endows the cabinet with excellent stability and anti-impact performance. The welding process strictly controls the joint gap, lap length and interlayer temperature to form an integral structure without stress concentration, which can withstand external loads such as strong winds and foreign object impacts outdoors, effectively protecting precision equipment such as internal voltage transformers and fuses from mechanical damage. This structural design also improves the corrosion resistance of the cabinet, adapts to corrosive environments such as coastal salt spray and industrial dust, reduces the risk of equipment failure caused by cabinet structure damage, and ensures the long-term safe operation of the power system.

[0021] From the perspective of the entire life cycle of the equipment, through multiple sealing protection and environmental isolation designs, the present invention constructs a clean and dry equipment operation space. It completely blocks the erosion of dust and moisture on the PT body and secondary circuit, avoids the aging of insulating materials, the corrosion of metal components, and the occurrence of short-circuit faults, and significantly improves the insulation performance and mechanical life of equipment such as voltage transformers and lightning arresters. Combined with the non-contact condition monitoring of the infrared temperature measurement window, the operating temperature of the equipment can be grasped in real time, early warning of abnormal conditions can be given, the frequency of planned power outage maintenance can be reduced, and the operation and maintenance cost of the entire life cycle can be lowered, providing long-term technical support for the reliable operation of the intelligent distribution network. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0023] Figure 1 It is a front view structural schematic diagram of a voltage transformer chamber of a ring main unit according to an embodiment of the present invention.

[0024] Figure 2 It is a side view structural schematic diagram of a voltage transformer chamber of a ring main unit according to an embodiment of the present invention.

[0025] Figure 3 It is a three-dimensional structural schematic diagram of a voltage transformer chamber of a ring main unit according to an embodiment of the present invention.

[0026] Figure 4 It is a structural schematic diagram of a voltage transformer compartment according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following description of each embodiment refers to the drawings to illustrate specific embodiments in which the present invention can be implemented. In the description of the present invention, it should be understood that the orientation or positional relationships indicated by terms such as "longitudinal", "length", "circumferential", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0028] Please also refer to Figures 1-3 As shown, an embodiment of the present invention provides a voltage transformer chamber 1 of a ring main unit, including:

[0029] The voltage transformer compartment 10 is arranged around the voltage transformer body and forms an integral welded structure with the switch gas tank and the mechanism compartment;

[0030] The cabinet door 11, which adopts a closed and detachable structure, is installed outside the voltage transformer compartment 10. The cabinet door 11 includes an integrated frame 112 and a panel 111 that is hermetically connected to the frame 112 through fasteners. An elastic sealing layer is provided between the panel 111 and the frame 112, and the welded joint between the cabinet door 11 and the voltage transformer compartment 10 is treated by a continuous sealing process.

[0031] Specifically, in the embodiment of the present invention, different from the single-door cabinet design of the nested type, this patent adopts a closed detachable door design. During normal operation, the PT room usually does not need to be frequently opened. Mainly installed in the PT room are equipment such as voltage transformers, fuses, and lightning arresters, which are used for functions such as voltage measurement, monitoring, protection, and providing operating power for other equipment. As long as the equipment is operating normally without signs of failure, such as abnormal voltage, fuse melting, lightning arrester operation, etc., the PT room is generally in a closed state to ensure a safe operating environment for the internal equipment. Therefore, in order to avoid deformation after long-term use, the embodiment of the present invention abandons the single-door design that is convenient to open and focuses on the anti-immersion design of the PT room, thereby reducing the need for multiple inspections and repairs of the contents inside the cabinet caused by dust and moisture entering the PT room.

[0032] The embodiment of the present invention adopts a fully enclosed design of welding and bolt disassembly and installation, specifically including:

[0033] Design of the frame 112 of the cabinet door 11: The external frame of the water-proof compartment is constructed using high-strength 304 stainless steel material and formed into an integral structure through welding technology to ensure no splicing gaps and prevent water from seeping in from the frame 112. In this embodiment, the frame 112 can make the protection level of the PT room cabinet door 11 reach the IP68 level, ensuring complete dust prevention and ensuring the sealing of the cabinet body in a continuous immersion environment. The size of the frame 112 is appropriately enlarged according to the actual specifications of the PT room 1, leaving a certain installation and maintenance space, while ensuring the stability of the overall structure and being able to withstand a certain external impact force. In terms of appearance, in order to avoid difficulties in use caused by anti-immersion modification, it maintains the same style as before the modification.

[0034] The cabinet door 11 is also made of high-strength 304 stainless steel material and welded to cover the surrounding area. A sealed stainless steel panel 111 is used with a sealing strip, and sealed by means of bolt fastening to ensure that the PT compartment 10 can be disassembled when the PT room 1 is opened. To ensure the safety of maintenance personnel and the sealing performance of the PT room, an infrared temperature measurement window 113 is designed at the upper part of the cabinet door 11, which can perform routine temperature measurement inspections without opening the PT room 1. The main function of the infrared temperature measurement window 113 is to test the temperature of the internal cable head with an infrared temperature gun without opening the lower cabinet door 11. The infrared temperature measurement window 113 is sealed around by a sealing strip made of silicone rubber material, and the mesh structure design ensures that the window will not hinder the heat conduction. The non-electrified part is behind the infrared temperature measurement window 113. During actual maintenance, the temperature of the internal cable head can be measured without opening the cabinet door 11, which can prevent the protection level of the cabinet door from decreasing due to frequent door opening and closing, and is also convenient for maintenance personnel to perform maintenance. Temperature measurement window baffles 114 inclined downward at 30° are arranged on both the upper and lower sides of the infrared temperature measurement window 113, which can adjust and guide the direction and flow rate of ventilation during equipment operation to ensure accurate measurement of the temperature of the internal cable head.

[0035] To further improve the water immersion resistance of the PT room 1, in the embodiment of the present invention, the part of the PT room 1 where the PT body is installed is secondarily sealed with an additional PT compartment 10.

[0036] Specifically, please also refer to Figure 4 As shown, a separate PT compartment 10 is additionally made inside the cable compartment 2. The PT compartment 10 is connected to the switch gas tank and the mechanism compartment by means of integral welding of 304 stainless steel to form a whole, ensuring no splicing gaps and preventing water from seeping in from the frame. The front of the PT compartment 10 has a sealed stainless steel cover plate 100 with a sealing strip, and is sealed by means of bolt fastening to ensure the waterproof performance of the front of the PT compartment 10. In addition, a high-strength glass observation window 101 is provided on the stainless steel cover plate 100, and the state of the PT and the PT joint can be viewed without disassembling the waterproof panel. The observation window 101 is made of tempered glass, the outer surface is bonded to the sealing panel with high-strength waterproof glass glue, and an annular steel pressing strip is provided on the inner surface, and a silicone rubber buffer layer is filled between the pressing strip and the panel.

[0037] In the embodiment of the present invention, the overall cabinet door 11 is welded by means of full welding of a high-strength 304 stainless steel frame 112. The surface of the cabinet body is covered by a stainless steel panel 111 and a sealing strip in cooperation with sealed bolts in the parts that need to be waterproof and rust-proof. First, a sealing strip made of silicone rubber material is used to cover the stainless steel frame 112 on the surface of the cabinet body, the stainless steel panel 111 is covered thereon, and then the stainless steel panel 111 and the sealing strip are fixed by means of bolt fastening.

[0038] In the welding process of the stainless steel panel 111, the following steps and parameters are operated to ensure the welding quality:

[0039] For thin plates with a thickness of 1 - 3 mm, a welding current of 25 - 40 A is used for a thickness of 1 mm, and a welding current of 80 - 100 A is used for a thickness of 3 mm; for thick plates with a thickness of 4 - 6 mm, the welding current is set at 100 - 150 A to avoid burn-through or intergranular corrosion caused by excessive current.

[0040] The welding speed is adjusted according to the plate thickness: when welding thin plates, the welding speed is controlled at 15 - 25 cm / min to reduce heat input; when welding thick plates, the welding speed is reduced to 8 cm / min to ensure full penetration of the weld. The arc voltage is controlled within the range of 6 - 20 V, and short arc operation (arc length is 0.5 - 1 times the tungsten electrode diameter) effectively reduces weld oxidation.

[0041] Select the tungsten electrode according to the welding current: a tungsten electrode with a diameter of 1.6 mm is used for a welding current of 50 - 100 A, and a tungsten electrode with a diameter of 2.4 mm is used for a welding current of 150 - 200 A. The tip of the tungsten electrode is ground into a 30° cone angle (DC straight polarity). The filler wire is selected as ER308 or H1Cr18Ni9Ti, with a diameter of φ1 - 3 mm, matching the composition of the base material. When welding thin plates, the welding temperature is controlled between 150°C - 350°C to ensure good fusion of the weld and avoid intergranular corrosion; when welding thick plates, the welding temperature is set at 250°C - 450°C. The specific temperature is dynamically adjusted according to parameters such as welding current, voltage, and welding speed.

[0042] Before welding, the groove needs to be standardized: for a V-shaped groove, the angle is 65° - 70°, the root face is 0 - 0.5 mm, and the gap is controlled within 1.5 - 3.5 mm. At the same time, clean the groove and the area within 20 mm on both sides, and use acetone or alcohol to thoroughly remove oil stains and oxide scales to ensure the cleanliness of the welding area.

[0043] During the welding process of the stainless steel panel 111, operate strictly in accordance with the following process requirements:

[0044] First, select the appropriate welding method according to the welding requirements: for butt welding, butt the edges of two 304 stainless steel plates or pipes, and control the joint gap within 0 - 0.5 mm to ensure the weld quality; for fillet welding, which is used for two perpendicularly intersecting 304 stainless steel components (such as the connection between a pipe and a flange), strictly control the welding angle and speed during welding to ensure uniform welds and sufficient strength; for lap welding, lap one 304 stainless steel plate on another steel plate, and the lap length is not less than 5 times the thickness of the thinner plate to ensure the weld strength.

[0045] During the welding process, high-frequency arc ignition is adopted. When finishing the welding, the molten pool is filled and the current is attenuated to prevent the formation of shrinkage cavities. The electrode movement method is selected according to the welding position: the "waving method" (large swing) is used for flat welding, and the "mop method" (small-amplitude uniform movement) is used for all-position welding to ensure the weld uniformity and quality. The shielding gas selected is argon with a purity ≥ 99.7%. The argon flow rate is calculated by the formula Q = (0.8 - 1.2)D (D is the nozzle inner diameter, unit: mm). The front shielding gas flow rate is set at 8 - 15 L / min, and the back argon filling protection (such as internal argon filling during pipeline welding) flow rate is 5 - 14 L / min. The distance between the nozzle and the workpiece is maintained within the range of 8 - 14 mm, and short-arc operation (arc length 2 - 4 mm) is adopted to reduce arc oxidation. In addition, the interpass temperature is strictly controlled to ensure it ≤ 150°C. When necessary, a wet towel is used for wiping or water cooling to accelerate heat dissipation, avoiding the temperature entering the sensitization range of 450 - 850°C to prevent carbide precipitation.

[0046] After welding, pickling and passivation are carried out by applying pickling and passivation paste. After 30 minutes, it is cleaned with a stainless steel brush until it turns silver-white to remove the oxide layer. For the splashed parts, a stainless steel flat spatula is used to remove the slag, and it is prohibited to scratch the surface with carbon steel tools.

[0047] Regarding the waterproof area sealing strip, a silica gel (white) sealing strip is adopted, with a density of 1.3 - 1.35 g / cm 3 ³, tensile strength of 6 - 8 MPa (ordinary type), elongation at break of 300% - 400%, hardness of 60 - 65 Shore A, tear strength ≥ 6 MPa; the temperature resistance range is -60°C to 250°C (long-term use temperature), and it can withstand 260°C in the short term, meeting the vast majority of use environments; in terms of corrosion resistance, it resists organic solvents, ozone, and ultraviolet aging; in terms of resilience, the permanent deformation rate is low (such as deformation ≤ 50% at 200°C for 48 hours). Its good performance enables it to meet the requirements in the cabinet door waterproof structure.

[0048] Regarding bolt fastening, based on the size of the cabinet body, bolts are fastened at the overlapping parts of the frame, sealing strip, and stainless steel baffle. The distribution method is uniform distribution. 4 - 7 bolts are used on the wide side of the cabinet door, and 2 - 5 bolts are used on the long side for fastening based on the size of different cabinet bodies. The uniformly distributed bolts can ensure the uniform fastening of the cabinet door in all directions and prevent moisture from entering the cabinet body.

[0049] Regarding the waterproof part: After verifying the waterproofness of no penetration at a depth of 1 meter for 30 minutes by immersion in water, it is confirmed that its protection level reaches IP68, ensuring complete dust prevention and the sealing of the cabinet body in a continuous immersion environment, effectively solving the problem of water seepage due to gaps in single-leaf doors caused by long-term use or processing precision problems.

[0050] The PT compartment 10 also welds the 304 stainless steel frame by full penetration welding, and the welding process is the same as that of the aforementioned stainless steel panel 111. Then, it is sealed with a sealing strip, a stainless steel baffle, and a sealing bolt. First, use a sealing strip made of silicone rubber to cover the stainless steel frame on the surface of the cabinet body, cover the stainless steel baffle on it, and then fix the stainless steel baffle and the sealing strip by bolt tightening. The thickness of the stainless steel baffle varies from 1 mm to 6 mm based on the waterproof performance requirements of different compartments. The requirement for bolt tightening in this compartment is more stringent. Based on the size of different compartments, 4 - 6 bolts are evenly tightened on the wide side, and 4 - 10 bolts are evenly tightened on the long side. This design further enhances the waterproof protection ability of key equipment on the basis of the traditional PT compartment sealing design of the ring main unit, effectively preventing moisture from penetrating around the PT body, ensuring the stable operation of equipment such as voltage transformers, enabling the protection level of the cabinet body to reach IP68 level, and significantly improving the reliability of the ring main unit in complex environments.

[0051] A high-strength glass observation window 101 is provided on the front of the PT compartment 10. The outer surface of the glass is bonded to the stainless steel baffle with high-strength waterproof glass glue, and a steel pressing strip is installed on the inner surface of the glass for fixation. This design not only ensures the waterproof performance of the front of the compartment but also facilitates the staff to check the status of the PT and PT joints at any time. Daily inspections can be carried out without disassembling the waterproof panel, taking into account both the waterproof effect and the operation convenience and equipment monitoring requirements, which is an important improvement to the traditional PT compartment design.

[0052] Compared with the prior art, the beneficial effects brought by the embodiments of the present invention are as follows:

[0053] Through the innovative design of the enclosed removable door and the secondary seal of the PT compartment, the present invention significantly improves the waterproof performance and operation reliability of the voltage transformer compartment of the ring main unit. The cabinet door adopts an integrated welded frame of high-strength 304 stainless steel, combined with a bolt-tightening sealing structure of a stainless steel baffle and a silicone rubber sealing strip, completely eliminating the problem of gap water seepage caused by processing accuracy or long-term deformation of the traditional single-opening door, and can block the intrusion of rainwater, moisture, and corrosive gases in a continuous immersion environment. The PT compartment, the switch gas tank, and the mechanism compartment form a secondary sealed space without splicing gaps through integral welding. The design of the sealed stainless steel cover plate and the high-strength glass observation window on the front can still provide an independent protection area for the voltage transformer body even when accidental water seepage occurs in other parts of the cabinet body, ensuring the stable operation of core functions such as voltage measurement and protection in complex environments such as humid and rainy conditions.

[0054] In terms of operation convenience and maintenance efficiency, the present invention takes into account both the sealing requirements and the convenience of maintenance. The infrared temperature measurement window at the lower part of the cabinet door and the high-strength glass observation window on the front of the PT compartment allow the staff to detect the temperature of the cable head with an infrared temperature gun and directly observe the status of the PT joint without opening the cabinet door or disassembling the sealing structure, avoiding the attenuation of the sealing performance caused by frequent opening and closing of the door. The detachable cabinet door and compartment design adopts a standardized bolt fastening structure, leaving a reasonable installation and maintenance space, which can be quickly disassembled and reset during equipment maintenance. Combined with the interference fit sealing of the silicone rubber sealing strip, it not only ensures the high efficiency of maintenance operations but also avoids the problem of opening and closing failure caused by rust of the traditional mechanical lock structure, significantly improving the operation and maintenance convenience.

[0055] In terms of structural design, the integrally welded frame made of 304 stainless steel endows the cabinet with excellent stability and impact resistance. The welding process strictly controls the joint gap, overlap length and interlayer temperature to form an integrated structure without stress concentration, which can withstand external loads such as strong winds and foreign object impacts outdoors, effectively protecting the internal precision equipment such as voltage transformers and fuses from mechanical damage. This structural design also improves the corrosion resistance of the cabinet, adapts to corrosive environments such as coastal salt spray and industrial dust, reduces the risk of equipment failure caused by cabinet structure damage, and ensures the long-term safe operation of the power system.

[0056] From the perspective of the entire life cycle of the equipment, the present invention constructs a clean and dry equipment operation space through multiple sealing protection and environmental isolation designs. It completely blocks the erosion of dust and moisture on the PT body and secondary circuit, avoids the occurrence of insulation material aging, metal component rust and short-circuit faults, and significantly improves the insulation performance and mechanical life of equipment such as voltage transformers and lightning arresters. Combined with the non-contact status monitoring of the infrared temperature measurement window, it can real-time monitor the operating temperature of the equipment, early warning of abnormal working conditions, reducing the frequency of planned power outage maintenance, and reducing the operation and maintenance costs throughout the life cycle, providing a long-term technical guarantee for the reliable operation of the intelligent distribution network.

[0057] The above-disclosed are only the preferred embodiments of the present invention. Of course, the scope of the rights of the present invention cannot be limited thereby. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A potential transformer chamber of a ring main unit, characterized in that, Including: A voltage transformer compartment, which is arranged around the voltage transformer body and forms an integral welded structure with the switch gas tank and the mechanism chamber; A cabinet door, which adopts a closed and detachable structure and is installed outside the voltage transformer compartment. The cabinet door includes an integrated frame and a panel hermetically connected to the frame through fasteners. An elastic sealing layer is provided between the panel and the frame, and the welded joint between the cabinet door and the voltage transformer compartment is treated by a continuous sealing process.

2. The potential transformer chamber of the ring main unit according to claim 1, characterized in that, An infrared temperature measurement window is provided at the upper part of the cabinet door. The temperature measurement area adopts a metal mesh heat conduction structure, and the infrared temperature measurement window is used for the infrared temperature measurement gun to measure the temperature of the internal cable head without opening the cabinet door.

3. The potential transformer chamber of the ring main unit according to claim 2, characterized in that, Temperature measurement window baffles inclined downward are arranged on both the upper and lower sides of the infrared temperature measurement window, which are used to guide the ventilation direction and adjust the ventilation flow rate.

4. The potential transformer chamber of the ring main unit according to claim 1, characterized in that, The frame and the panel are made of 304 stainless steel. The elastic sealing layer is a silicone rubber sealing strip with a hardness of 60-65 Shore A and an elongation at break ≥ 300%.

5. The potential transformer chamber of the ring main unit according to claim 1, wherein The continuous sealing process includes using V-groove welding with a groove angle of 65-70°, a root face size of 0-0.5 mm, the interlayer temperature during welding is controlled at ≤ 150 °C, and all-position welding is implemented by argon-shielded welding.

6. The potential transformer chamber of the ring main unit according to claim 5, wherein The process parameters of the argon-shielded welding include: welding current 25-150 A, arc voltage 6-20 V, argon flow rate 8-15 L / min, tungsten electrode diameter 1.6-2.4 mm, welding speed 8-25 cm / min.

7. The potential transformer chamber of the ring main unit according to claim 1, characterized in that, The voltage transformer compartment has a stainless steel cover plate, and an observation window is also provided on the stainless steel cover plate.

8. The potential transformer chamber of the ring main unit according to claim 7, characterized in that, The observation window is made of tempered glass. The outer surface is bonded to the sealing panel through waterproof glass glue, and a ring-shaped steel pressing strip is provided on the inner surface. A silicone rubber buffer layer is filled between the ring-shaped steel pressing strip and the sealing panel.

9. The potential transformer chamber of the ring main unit according to claim 1, characterized in that The silicone rubber sealing strip between the panel and the frame is of "P" type or "E" type structure, and the silicone rubber sealing strip forms an interference fit through bolt fastening.

10. The potential transformer chamber of the ring main unit according to claim 1, wherein, The welding methods of the voltage transformer compartment include butt welding, fillet welding or lap welding. The joint gap of butt welding is controlled at 0-0.5 mm, and the lap length of lap welding is not less than 5 times the thickness of the thinner plate; high-frequency arc starting is adopted and the molten pool is filled during arc stopping. The rocking method is adopted during flat welding and the mop method is adopted during all-position welding for the welding rod movement.

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