Installation and debugging method of transformer in power transmission and distribution project

Abstract

The application relates to the technical field of transformers, in particular to a transformer installation and debugging method in power transmission and distribution engineering, which comprises the following steps: connecting a lifting steel wire rope of a crane with a falling micro-control device, connecting the lower end of the falling micro-control device with a transformer lifting device, lifting the transformer to above an installation foundation through the falling micro-control device of the crane, adjusting the position of the transformer to align the transformer with pre-buried parts or installation bolt holes on the foundation; the transformer installation and debugging method is suitable for the installation of intelligent large transformers, can reduce the lifting impact on the intelligent large transformers, and can visually and accurately control the slow descent of the transformer when the transformer falls onto the foundation, so that the falling control is more accurate and stable.

Description

Technical Field

[0001] This invention relates to the field of transformer technology, specifically to methods for installing and commissioning transformers in power transmission and distribution projects. Background Technology

[0002] During the installation of intelligent large transformers, cranes and other lifting equipment are required to hoist the large transformers onto the installation foundation. During this process, workers on the foundation and crane operators need to communicate remotely to control the transformer's position. Especially at the moment the transformer falls onto the foundation, the communication delay with the crane operator and the difficulty in precisely controlling the crane's wire ropes can easily cause a significant impact force when the large transformer lands on the foundation. Intelligent large transformers have strict requirements for transportation and installation; the tilt angle cannot exceed 15 degrees during the entire process, and impact forces are strictly prohibited. The impact force generated when the transformer lands on the foundation poses potential risks such as failure of the core clamping device, misalignment of silicon steel sheets, insulation damage, and stress on weld points. Improvements are needed to address these issues. Summary of the Invention

[0003] The purpose of this invention is to provide a method for installing and commissioning transformers in power transmission and distribution projects, so as to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for the installation and commissioning of transformers in power transmission and distribution projects, the method comprising the following steps: Step 1: Connect the hoisting wire rope of the crane to the lowering micro-control device. Connect the lower end of the lowering micro-control device to the transformer hoisting device. The crane uses the lowering micro-control device to hoist the transformer to the installation foundation. Adjust the position of the transformer so that it is aligned with the embedded parts or installation bolt holes on the foundation. Step two: First, the crane lowers the transformer using a wire rope. After it is a certain distance from the installation foundation, the lowering micro-control device controls the transformer to descend smoothly onto the foundation, avoiding collisions and impacts. Step 3: After the transformer is in place, use jacks and a level to add or remove shims under the transformer base to ensure the transformer is level. Select appropriate bolts according to the transformer specifications and installation requirements, and tighten them to the specified torque. Step four: Install accessories and connect cables; Step 5, commissioning and testing, specifically including insulation testing, turns ratio testing, polarity testing, no-load testing, and load testing.

[0005] The accessories in step four include a radiator, a gas relay, and an oil tank. The oil tank is installed on the top of the transformer at the corresponding position via a pipe. The gas relay is installed on the pipe between the transformer and the oil tank. When installing, pay attention to the direction of the gas relay so that its arrow points to the oil tank. Install the radiator on both sides of the transformer's oil tank and connect the pipe between the radiator and the oil tank, ensuring that the connection is firm and the seal is reliable.

[0006] The landing micro-control device specifically includes an outer cylinder and an inner chamber opened inside the outer cylinder. A piston main plate is provided in the inner chamber, and there is an airtight contact between the inner chamber and the piston main plate. A connecting shaft is fixedly installed on the piston main plate, and an exhaust check valve and a flow limiting structure are installed on the outer cylinder. Both the exhaust check valve and the flow limiting structure are connected to the upper part of the inner chamber. The exhaust check valve allows the gas in the inner chamber to flow unidirectionally to the outside. When the flow limiting structure is closed, the outside gas will not enter the inner chamber. When the flow limiting structure is open, the outside gas enters the inner chamber after being limited by the flow limiting structure.

[0007] The flow-limiting structure includes a top groove, a flow-limiting micro-hole, and a coaxial chamber. The top groove, the flow-limiting micro-hole, and the coaxial chamber are all formed in the outer cylinder. The top groove is connected to the coaxial chamber through the flow-limiting micro-hole, and the top groove is connected to the upper part of the inner chamber.

[0008] An adjusting screw is helically installed in the coaxial chamber. One end of the adjusting screw is fixedly provided with a frustum head, and the other end of the adjusting screw is fixedly provided with an adjusting wheel. By rotating the adjusting wheel, the adjusting screw is rotated, which in turn drives the adjusting screw and the frustum head to move axially. When the frustum head is pressed into contact with the end of the flow-limiting microorifice, the flow-limiting microorifice can be closed. When the frustum head is separated from the flow-limiting microorifice, the flow-limiting microorifice is connected to the coaxial chamber and opened.

[0009] The side wall of the coaxial chamber is provided with an air inlet filter hole, and a filter cotton core is provided in the air inlet filter hole.

[0010] A sealing rubber ring is embedded on the outer surface of the piston main plate. The piston main plate slides and seals against the inner wall surface of the inner cavity through the sealing rubber ring. An elliptical annular cavity is formed in the sealing rubber ring. The elliptical annular cavity is circular and has an elliptical cross-section.

[0011] The sealing rubber ring is provided with a sealing connection nozzle, which is in communication with the elliptical ring cavity. The piston main plate is provided with a connection slot, and the sealing connection nozzle is sealed and inserted into the connection slot. An interactive flow channel is provided inside the piston main plate, and one end of the interactive flow channel is in communication with the elliptical ring cavity through the sealing connection nozzle.

[0012] The connecting shaft has a sealed shaft cavity, and a metal corrugated cover is provided in the sealed shaft cavity. The metal corrugated cover cooperates with the side wall and top wall of the connecting shaft to form a sealed cavity, and the sealed cavity is connected to the interactive flow channel. The sealed cavity, the interactive flow channel and the elliptical annular cavity are all filled with liquid medium.

[0013] A circular groove is formed on the upper surface of the piston main plate. A negative pressure corrugated cover is provided in the circular groove. A synchronous sealing shaft is fixedly connected between the negative pressure corrugated cover and the metal corrugated cover. The synchronous sealing shaft passes through the piston main plate and is in sealing contact with the piston main plate.

[0014] When the piston main plate is under negative pressure, the negative pressure acts on the negative pressure bellows cover, which can drive the synchronous sealing shaft to move upward, so that the liquid medium above the metal bellows cover is squeezed and enters the elliptical annular cavity through the interactive flow channel; the bottom of the circular groove is provided with an oblique vent hole for external communication.

[0015] A pressure sensor for detecting the gas pressure inside the sealed shaft cavity is fixedly installed on the inner wall surface of the sealed shaft cavity. The sealed shaft cavity is equipped with a heat-resistant bracket and a heating wire. The heating wire is supported by the heat-resistant bracket. The outside of the connecting shaft is equipped with a secondary control socket. The heating wire and the air pressure sensor are connected to the outside through the secondary control socket.

[0016] Compared with the prior art, the beneficial effects of the present invention are: The transformer installation and commissioning method of this invention is applicable to the installation of intelligent large transformers. By using a specially designed descent micro-control device, the lifting impact on the intelligent large transformer can be reduced during the hoisting process. When the transformer is lowered onto the foundation, workers can visually and precisely control the slow descent of the transformer from a terminal position near the transformer using the descent micro-control device. This makes the descent control more precise and stable, significantly reducing the impact force generated when the transformer lands on the foundation and reducing the risk of damage during installation.

[0017] This invention, through the combination of a negative pressure corrugated cover, a metal corrugated cover, and a synchronous sealing shaft, enables the sealing performance between the sealing rubber ring and the inner cavity to automatically change according to the weight of different transformers. The heavier the transformer being lifted by the lowering micro-control device, the higher the sealing performance between the sealing rubber ring and the inner cavity, achieving adaptive control. This reduces unnecessary wear when lifting lighter transformers and minimizes the contact pressure between the sealing rubber ring and the inner cavity after lifting, facilitating manual pushing of the connecting shaft back into the outer cylinder.

[0018] This invention, through the combination of a sealed shaft cavity, a pressure sensor, and a heating wire, can actively change the relationship between the sealing rubber ring and the inner cavity, as well as the weight of the transformer, when needed, to achieve two-stage precise control according to different requirements. Attached Figure Description

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

[0020] Figure 2 This is another schematic diagram of the overall structure of the present invention.

[0021] Figure 3 This is a three-dimensional half-sectional schematic diagram of the present invention.

[0022] Figure 4 for Figure 3 Enlarged schematic diagram of region A in the middle.

[0023] Figure 5 This is a three-dimensional half-section front view of the present invention.

[0024] Figure 6 for Figure 5 Enlarged schematic diagram of region B in the middle.

[0025] In the diagram: 1. Outer cylinder; 2. Inner chamber; 3. Piston main plate; 4. Connecting shaft; 5. Exhaust check valve; 101. Top groove; 102. Flow-limiting micro-orifice; 103. Coaxial chamber; 104. Adjusting screw; 105. Frustum head; 106. Adjusting dial; 107. Intake filter; 108. Filter core; 301. Sealing rubber ring; 302. Elliptical ring cavity; 303. Sealing connector; 304. Connecting slot; 305. Interactive flow channel; 306. Sealed shaft cavity; 307. Metal corrugated cover; 308. Circular groove; 309. Negative pressure corrugated cover; 310. Synchronous sealing shaft; 311. Slanted vent; 401. Pressure sensor; 402. Heat-resistant bracket; 403. Heating wire; 404. Secondary control socket; 6. Lifting ring; 7. Breathing bottom hole. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Please see Figures 1 to 6 This invention provides a technical solution: a method for the installation and commissioning of transformers in power transmission and distribution projects, the method comprising the following steps: Step 1: Connect the hoisting wire rope of the crane to the lowering micro-control device. Connect the lower end of the lowering micro-control device to the transformer hoisting device. The crane uses the lowering micro-control device to hoist the transformer to the installation foundation. Adjust the position of the transformer so that it is aligned with the embedded parts or installation bolt holes on the foundation. Step two: First, the crane lowers the transformer using a wire rope. After it is a certain distance from the installation foundation, the lowering micro-control device controls the transformer to descend smoothly onto the foundation, avoiding collisions and impacts. Step 3: After the transformer is in place, use jacks and a level to add or remove shims under the transformer base to ensure the transformer is level. Select appropriate bolts according to the transformer specifications and installation requirements, and tighten them to the specified torque. Step four: Install accessories and connect cables; install the oil conservator on the top of the transformer via a pipe at the corresponding position, and install the gas relay on the pipe between the transformer and the oil conservator. When installing, pay attention to the direction of the gas relay so that its arrow points to the oil conservator; install the radiator on both sides of the transformer's oil tank, and connect the pipe between the radiator and the oil tank, ensuring that the connection is firm and the seal is reliable.

[0028] Step five involves commissioning and testing, specifically including insulation testing, turns ratio testing, polarity testing, no-load testing, and load testing. During insulation testing, a megohmmeter is used to measure the insulation resistance between the high-voltage and low-voltage windings, between the windings and the core, and between the windings and the casing.

[0029] During the turns ratio test, a turns ratio bridge is used to test the turns ratio at each tap position of the transformer. During the test, the test leads of the turns ratio bridge are connected to the high and low voltage windings of the transformer, and the corresponding tap position is selected for testing. The turns ratio value displayed by the turns ratio bridge is read and recorded. The turns ratio value should match the parameters on the transformer's nameplate.

[0030] A multimeter or polarity tester is used to test the polarity of the transformer windings during polarity testing.

[0031] During the no-load test, connect the high-voltage side of the transformer to a power source with the rated voltage and leave the low-voltage side open. Under no-load conditions, measure the no-load current and no-load loss of the transformer. The no-load current and no-load loss should meet the specified requirements. If they exceed the allowable range, the cause should be found and dealt with.

[0032] During the load test, a suitable load is connected to the low-voltage side of the transformer, and the load current is gradually increased until the transformer reaches its rated load operation. During the load operation, the load loss and short-circuit impedance of the transformer are measured, and the load loss and short-circuit impedance should meet the specified requirements.

[0033] The landing micro-control device specifically includes an outer cylinder 1 and an inner chamber 2 located inside the outer cylinder 1. A piston main plate 3 is disposed within the inner chamber 2, and the inner chamber 2 and the piston main plate 3 are in airtight contact. A connecting shaft 4 is fixedly mounted on the piston main plate 3. An exhaust check valve 5 and a flow-limiting structure are disposed on the outer cylinder 1. Figure 4 As shown, the exhaust check valve 5 is spirally sealed inside the outer cylinder 1. Both the exhaust check valve 5 and the flow limiting structure are connected to the upper part of the inner chamber 2. The exhaust check valve 5 allows the gas in the inner chamber 2 to flow unidirectionally to the outside. When the flow limiting structure is closed, the outside gas will not enter the inner chamber 2. When the flow limiting structure is open, the outside gas enters the inner chamber 2 after being limited by the flow limiting structure.

[0034] The flow-limiting structure includes a top groove 101, a flow-limiting micro-hole 102, and a coaxial chamber 103. The top groove 101, the flow-limiting micro-hole 102, and the coaxial chamber 103 are all opened in the outer cylinder 1. The top groove 101 is connected to the coaxial chamber 103 through the flow-limiting micro-hole 102, and the top groove 101 is connected to the upper part of the inner chamber 2. An adjusting screw 104 is screwed into the coaxial chamber 103. A frustum head 105 is fixedly provided at one end of the adjusting screw 104, and an adjusting wheel 106 is fixedly provided at the other end of the adjusting screw 104. By rotating the adjusting wheel 106, the adjusting screw 104 is rotated, which in turn drives the adjusting screw 104 and the frustum head 105 to move axially. When the frustum head 105 is pressed into contact with the end of the flow-limiting microhole 102, the flow-limiting microhole 102 can be closed. When the frustum head 105 is separated from the flow-limiting microhole 102, the flow-limiting microhole 102 is connected to and opened in the coaxial chamber 103.

[0035] The side wall of the coaxial chamber 103 is provided with an air inlet filter hole 107 extending outward, and a filter cotton core 108 is provided in the air inlet filter hole 107.

[0036] A sealing rubber ring 301 is embedded on the outer surface of the piston main plate 3. The piston main plate 3 slides and seals against the inner wall surface of the inner cavity 2 through the sealing rubber ring 301. An elliptical annular cavity 302 is formed in the sealing rubber ring 301. The elliptical annular cavity 302 is circular and has an elliptical cross section.

[0037] A sealing rubber ring 301 is provided with a sealing connector 303, which is connected to the elliptical ring cavity 302. The piston main plate 3 is provided with a connecting slot 304. The sealing connector 303 is inserted into the connecting slot 304. During installation, glue is applied between the sealing connector 303 and the connecting slot 304. After the sealing connector 303 and the connecting slot 304 are inserted and matched, the glue solidifies to ensure the sealing between the sealing connector 303 and the connecting slot 304.

[0038] The piston main disk 3 has an interactive flow channel 305 inside, and one end of the interactive flow channel 305 is connected to the elliptical annular cavity 302 through a sealing connection nozzle 303.

[0039] A sealed shaft cavity 306 is provided in the connecting shaft 4, and a metal corrugated cover 307 is provided in the sealed shaft cavity 306. The metal corrugated cover 307 cooperates with the side wall and top wall of the connecting shaft 4 to form a sealed cavity, and the sealed cavity is connected to the interactive flow channel 305. The sealed cavity, the interactive flow channel 305 and the elliptical annular cavity 302 are all filled with liquid medium. The liquid medium does not need to come into contact with the rubber material to cause corrosion. The pressure transmission efficiency is improved by utilizing the incompressible property of the liquid.

[0040] A circular groove 308 is formed on the upper surface of the piston main disc 3. A negative pressure corrugated cover 309 is disposed in the circular groove 308. A synchronous sealing shaft 310 is fixedly connected between the negative pressure corrugated cover 309 and the metal corrugated cover 307. The synchronous sealing shaft 310 passes through the piston main disc 3 and is in sealing contact with the piston main disc 3. The metal corrugated cover 307 and the negative pressure corrugated cover 309 are as follows: Figure 6 As shown, all components are made of metal and are connected to the inner walls of the circular groove 308 and the sealed shaft cavity 306 by welding to ensure stable sealing performance. Furthermore, both the metal corrugated cover 307 and the negative pressure corrugated cover 309 have corrugated cross-sections, allowing for concave-convex deformation.

[0041] When the piston main plate 3 is under negative pressure, the negative pressure acts on the negative pressure bellows cover 309, which can drive the synchronous sealing shaft 310 to move upward, so that the liquid medium above the metal bellows cover 307 is squeezed and enters the elliptical annular cavity 302 through the interactive flow channel 305; the bottom of the circular groove 308 is provided with an inclined vent hole 311 for external communication.

[0042] A pressure sensor 401 for detecting the gas pressure inside the sealed shaft cavity 306 is fixedly installed on the inner wall surface of the sealed shaft cavity 306. A heat-resistant bracket 402 and a heating wire 403 are provided in the sealed shaft cavity 306. The heating wire 403 is supported by the heat-resistant bracket 402. A secondary control socket 404 is provided on the outside of the connecting shaft 4. The heating wire 403 and the air pressure sensor 401 are connected to the outside through the secondary control socket 404.

[0043] like Figure 2 and Figure 3 As shown, the upper part of the outer cylinder 1 and the lower end of the connecting shaft 4 are respectively fixedly provided with lifting rings 6. In use, the lifting rings 6 at the upper part of the outer cylinder 1 are connected to the wire rope of the crane, and the lifting rings 6 at the lower end of the connecting shaft 4 are connected to the transformer hoisting.

[0044] like Figure 3As shown, a breathing hole 7 is provided through the bottom of the outer cylinder 1. The breathing hole 7 allows the gas below the piston main plate 3 to exchange with the external atmospheric pressure through the breathing hole 7 when the piston main plate 3 moves up and down inside the inner chamber 2. A filter structure such as a filter membrane can be installed in the breathing hole 7 to prevent sand and gravel and other debris from entering the inner chamber 2 through the breathing hole 7 in the harsh environment of the construction site, thus affecting the life of the device.

[0045] When the transformer is lifted using the lowering microcontroller, the connecting shaft 4 is first fully retracted into the inner chamber 2, at which point the piston main plate 3 is at the top of the inner chamber 2. Initially, the frustum top 105 blocks and seals the current-limiting micro-orifice 102. The crane pulls the lowering microcontroller upwards via a wire rope. The moment the lowering microcontroller lifts the transformer, the upper part of the piston main plate 3 enters a negative pressure state. Furthermore, the piston main plate 3 generates negative pressure through a slight elastic downward movement, which mitigates the impact of the wire rope traction and reduces the lifting impact on the intelligent large transformer.

[0046] After the transformer is moved above the installation foundation by a crane, the steel wire rope is first released by the crane to control the transformer to move down. When the transformer is a certain distance from the installation foundation, the workers on the installation foundation operate the descent micro-control device to make the transformer continue to move down.

[0047] The worker manually rotates the adjusting wheel 106, moving the frustum top 105 away from the flow-limiting micro-orifice 102. At this time, the flow-limiting micro-orifice 102 is connected to the coaxial chamber 103. External gas, after being filtered by the filter cotton core 108, enters the flow-limiting micro-orifice 102 through the air inlet filter 107 and the coaxial chamber 103. The flow is limited by the flow-limiting micro-orifice 102 and finally enters above the piston main plate 3. Due to the air intake above the piston main plate 3, the piston main plate 3 slowly moves downward inside the inner chamber 2, causing the connecting shaft 4 to move downward and extend relative to the outer cylinder 1, and the transformer to move downward. By rotating the adjusting wheel 106, the worker changes the distance between the flow-limiting micro-orifice 102 and the frustum top 105, thereby changing the air intake flow and opening / closing status of the flow-limiting micro-orifice 102. This allows for speed control and the ability to pause at any time during the transformer's descent, significantly reducing the possibility of the transformer being subjected to impact force when it lands on the installation foundation.

[0048] After landing, remove the landing microcontroller and push the connecting shaft 4 back into the outer cylinder 1. The gas above the piston main plate 3 is discharged to the outside through the exhaust check valve 5.

[0049] During the above process, the heavier the transformer being hoisted, the greater the negative pressure generated above the piston main plate 3, such as... Figure 4 and Figure 6As shown, negative pressure acts on the negative pressure bellows cover 309, causing it to bulge upwards. This drives the synchronous sealing shaft 310 to move upwards. As the synchronous sealing shaft 310 moves upwards, the metal bellows cover 307, driven by the synchronous sealing shaft 310, further compresses the liquid medium above it into the elliptical annular cavity 302 through the interactive flow channel 305. This causes the elliptical annular cavity 302 to expand, increasing the contact pressure between the sealing rubber ring 301 and the inner chamber 2. The higher the contact pressure, the better the sealing performance. Furthermore, the contact pressure is directly proportional to the transformer weight, achieving automatic adaptation.

[0050] By presetting the diameter ratio of the negative pressure corrugated cover 309 and the metal corrugated cover 307, the pressure application area can be changed, thereby achieving the setting of the initial conversion ratio.

[0051] like Figure 4 and Figure 6 As shown, the compressive force on the liquid medium above the corrugated metal cover 307 is equal to the sum of the pressure generated by the upward movement of the synchronous sealing shaft 310 and the pressure on the lower surface of the corrugated metal cover 307. When the pressure in the sealed shaft cavity 306 increases, the pressure acting on the lower surface of the corrugated metal cover 307 assists the synchronous sealing shaft 310 in compressing the liquid medium above the corrugated metal cover 307. Therefore, as... Figure 2 and Figure 3 As shown, when electrical control adjustments are required, a conductive connection is established between the pressure sensor 401 and the heating wire 403 and the outside environment through the secondary control socket 404. Power is supplied to the heating wire 403, causing it to heat the gas in the sealed shaft cavity 306. The gas in the sealed shaft cavity 306 expands due to heat, increasing its pressure. This increases the pressure acting on the lower surface of the metal corrugated cover 307, thus increasing the contact pressure between the sealing rubber ring 301 and the inner chamber 2 when hoisting a transformer of the same weight, enabling secondary precise proportional control. The pressure sensor 401 detects the pressure in the sealed shaft cavity 306, achieving closed-loop feedback control and improving accuracy.

[0052] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for installing and commissioning transformers in power transmission and distribution projects, characterized in that, The method includes the following steps: Step 1: Connect the hoisting wire rope of the crane to the lowering micro-control device. Connect the lower end of the lowering micro-control device to the transformer hoisting device. The crane uses the lowering micro-control device to hoist the transformer to the installation foundation. Adjust the position of the transformer so that it is aligned with the embedded parts or installation bolt holes on the foundation. Step two: First, the crane lowers the transformer using a wire rope. After it is a certain distance from the installation foundation, the lowering micro-control device controls the transformer to descend smoothly onto the foundation, avoiding collisions and impacts. Step 3: After the transformer is in place, use jacks and a level to add or remove shims under the transformer base to ensure the transformer is level. Select appropriate bolts according to the transformer specifications and installation requirements, and tighten them to the specified torque. Step four: Install accessories and connect cables; Step 5, commissioning and testing, specifically including insulation testing, turns ratio testing, polarity testing, no-load testing, and load testing; The landing micro-control device specifically includes an outer cylinder and an inner chamber located inside the outer cylinder. A piston main plate is disposed within the inner chamber, and the inner chamber and the piston main plate are in airtight contact. A connecting shaft is fixedly mounted on the piston main plate. An exhaust check valve and a flow-limiting structure are disposed on the outer cylinder. Both the exhaust check valve and the flow-limiting structure are connected to the upper part of the inner chamber. The exhaust check valve allows gas in the inner chamber to flow unidirectionally to the outside. When the flow-limiting structure is closed, outside gas will not enter the inner chamber. When the flow-limiting structure is open, outside gas enters the inner chamber after being limited by the flow-limiting structure. The flow-limiting structure includes a top groove, flow-limiting micro-holes, and... The coaxial chamber, including the top groove, the flow-limiting micro-orifice, and the coaxial chamber itself, is located within the outer cylinder. The top groove communicates with the coaxial chamber via the flow-limiting micro-orifice and is also connected to the upper part of the inner chamber. An adjusting screw is helically installed within the coaxial chamber. One end of the adjusting screw is fixedly fitted with a frustum-shaped top, and the other end is fixedly fitted with an adjusting wheel. Rotating the adjusting wheel causes the adjusting screw to rotate, which in turn drives the adjusting screw and the frustum-shaped top to move axially. When the frustum-shaped top comes into contact with the end of the flow-limiting micro-orifice, it closes the micro-orifice. When the frustum-shaped top separates from the micro-orifice, the micro-orifice opens and communicates with the coaxial chamber.

2. The method for installing and commissioning transformers in power transmission and distribution projects according to claim 1, characterized in that: The accessories in step four include a radiator, a gas relay, and an oil tank. The oil tank is installed on the top of the transformer at the corresponding position via a pipe. The gas relay is installed on the pipe between the transformer and the oil tank. When installing, pay attention to the direction of the gas relay so that its arrow points to the oil tank. Install the radiator on both sides of the transformer's oil tank and connect the pipe between the radiator and the oil tank, ensuring that the connection is firm and the seal is reliable.

3. The method for installing and commissioning transformers in power transmission and distribution projects according to claim 1, characterized in that: The side wall of the coaxial chamber is provided with an air inlet filter hole, and a filter cotton core is provided in the air inlet filter hole.

4. The method for installing and commissioning transformers in power transmission and distribution projects according to claim 1, characterized in that: A sealing rubber ring is embedded on the outer surface of the piston main plate. The piston main plate slides and seals against the inner wall surface of the inner cavity through the sealing rubber ring. An elliptical annular cavity is formed in the sealing rubber ring. The elliptical annular cavity is circular and has an elliptical cross-section.

5. The method for installing and commissioning transformers in power transmission and distribution projects according to claim 4, characterized in that: The sealing rubber ring is provided with a sealing connection nozzle, which is in communication with the elliptical ring cavity. The piston main plate is provided with a connection slot, and the sealing connection nozzle is sealed and inserted into the connection slot. The piston main disc has an interactive flow channel inside, and one end of the interactive flow channel is connected to the elliptical annular cavity through a sealing connection nozzle.

6. The method for installing and commissioning transformers in power transmission and distribution projects according to claim 5, characterized in that: The connecting shaft has a sealed shaft cavity, and a metal corrugated cover is provided in the sealed shaft cavity. The metal corrugated cover cooperates with the side wall and top wall of the connecting shaft to form a sealed cavity, and the sealed cavity is connected to the interactive flow channel. The sealed cavity, the interactive flow channel and the elliptical annular cavity are all filled with liquid medium.

7. The method for installing and commissioning transformers in power transmission and distribution projects according to claim 6, characterized in that: A circular groove is formed on the upper surface of the piston main plate. A negative pressure corrugated cover is provided in the circular groove. A synchronous sealing shaft is fixedly connected between the negative pressure corrugated cover and the metal corrugated cover. The synchronous sealing shaft passes through the piston main plate and is in sealing contact with the piston main plate.

8. The method for installing and commissioning transformers in power transmission and distribution projects according to claim 7, characterized in that: When the piston main plate is under negative pressure, the negative pressure acts on the negative pressure bellows cover, which can drive the synchronous sealing shaft to move upward, so that the liquid medium above the metal bellows cover is squeezed and enters the elliptical annular cavity through the interactive flow channel; the bottom of the circular groove is provided with an oblique vent hole for external communication.

9. The method for installing and commissioning transformers in power transmission and distribution projects according to claim 6, characterized in that: A pressure sensor for detecting the gas pressure inside the sealed shaft cavity is fixedly installed on the inner wall surface of the sealed shaft cavity. The sealed shaft cavity is equipped with a heat-resistant bracket and a heating wire. The heating wire is supported by the heat-resistant bracket. The outside of the connecting shaft is equipped with a secondary control socket. The heating wire and the air pressure sensor are connected to the outside through the secondary control socket.

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