Air pressure adjusting device and method for oil-immersed transformer

Abstract

The invention relates to the technical field of transformers, and discloses an oil-immersed transformer air pressure adjusting device and method.The oil-immersed transformer air pressure adjusting device comprises an oil tank installed at the top of a transformer and a two-way pressure adjusting valve A. The two-way pressure adjusting valve A communicates with the interior of the transformer, and an oil conveying pipe is installed at the top end of the two-way pressure adjusting valve A and communicates with a one-way valve A and a one-way valve B; the one-way valve A is communicated with the bottom end of the oil tank, the one-way valve B is connected with the filter tank, and the filter tank is communicated with the oil tank through a pipeline. The two-way pressure regulating valve A and the two-way pressure regulating valve B are arranged, and two-way regulation can be automatically carried out according to air pressure changes in the transformer. When the air pressure is increased or decreased, the valve body can be timely conducted, so that the insulating oil flows into or out of the transformer, the air pressure in the transformer is always in a proper range, and the safe operation of the transformer is effectively protected.

Description

Technical Field

[0001] The invention relates to the technical field of transformers, and in particular to an oil-immersed transformer air pressure regulating device and method. Background Art

[0002] Oil-immersed transformers use oil as the main insulation means of the transformer and rely on oil as a cooling medium, such as oil-immersed self-cooling, oil-immersed air cooling, oil-immersed water cooling and forced oil circulation. Due to long-term immersion in the transformer, oil can penetrate into the silicon steel sheets between the layers of the oil-immersed transformer, and the transformer oil has elasticity and acts as a buffer, so the oil-immersed transformer has low noise.

[0003] Regulating the gas pressure of oil-immersed transformers to ensure their normal operation and life is an important aspect of power system maintenance. Adjusting the gas pressure usually involves monitoring and adjusting the transformer oil pressure, which is not only related to the insulation performance of the transformer, but also directly affects the cooling effect and the realization of the protection function. The gas pressure regulation is mainly to maintain the stability of the internal pressure of the transformer, to avoid damage to the oil tank due to excessive pressure, or to affect the insulation performance and cooling effect due to low pressure. The pressure relief valve (also called a safety airway or explosion-proof pipe) can automatically open when the internal pressure exceeds the set value, releasing part of the insulating oil to reduce the pressure and prevent damage to the transformer.

[0004] At present, oil-immersed transformers use pressure relief valves to adjust the internal pressure of the transformer. However, after the insulating oil is discharged, there will be a lack of oil inside the transformer. Therefore, the transformer needs to be refueled regularly, otherwise there will be safety hazards inside the transformer due to lack of oil. For this reason, the present invention provides an oil-immersed transformer air pressure regulating device and method. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides an oil-immersed transformer air pressure regulating device and method, which can adjust the transformer air pressure and timely remove or inject insulating oil for adjustment to maintain the transformer air pressure normal.

[0006] The present invention provides the following technical solution: an oil-immersed transformer gas pressure regulating device, comprising an oil tank and a bidirectional pressure regulating valve A installed on the top of the transformer, and the bidirectional pressure regulating valve A is connected to the inside of the transformer, an oil delivery pipe is installed on the top of the bidirectional pressure regulating valve A, and the oil delivery pipe is connected to a one-way valve A and a one-way valve B, and the conduction directions of the one-way valve A and the one-way valve B are opposite, the one-way valve A is connected to the bottom of the oil tank, the one-way valve B is connected to a filter box, and the filter box is connected to the oil tank through a pipeline;

[0007] The air pressure in the transformer increases, causing the insulating oil in the transformer to be introduced into the oil pipeline through the A two-way pressure regulating valve, and then introduced into the filter box through the B one-way valve for filtration, and then introduced into the oil tank;

[0008] The air pressure in the transformer decreases, and the insulating oil in the oil tank is sucked into the oil pipeline through the A one-way valve, and then introduced into the transformer through the A two-way pressure regulating valve;

[0009] An exhaust hole is provided at the top of the oil tank, and an oil-gas separator is provided below the exhaust hole. A B two-way pressure regulating valve is installed on the exhaust hole of the oil tank, and an L-shaped exhaust pipe is installed at the top of the B two-way pressure regulating valve, and the air pressure inside the oil tank is adjusted by the B two-way pressure regulating valve;

[0010] An isolation structure for separating water from insulating oil is installed inside the oil tank, and the insulating oil A after water separation is led out through a one-way valve and injected into the transformer.

[0011] Preferably, the A bidirectional pressure-regulating valve and the B bidirectional pressure-regulating valve both include a valve body and a sealing ring installed inside the valve body, two bosses located on both sides of the sealing ring are installed inside the valve body, and guide plates are installed on the two bosses, a slidable threaded column is provided at the center of the two guide plates, and a piston located on the inner side of the sealing ring is provided in the middle of the threaded column, and a reset spring and an adjusting nut are provided at both ends of the threaded column, and the reset spring is compressed by adjusting the position of the nut so that the piston is located in the middle of the sealing ring.

[0012] Preferably, the inner diameter of the boss is larger than the inner diameter of the sealing ring, so that the piston can pass through the boss and slide in the sealing ring. When the air pressure in the transformer increases or decreases, the air pressure pushes the piston up and down. When the piston is separated from the sealing ring, the valve body is turned on and the air pressure is adjusted.

[0013] Preferably, the A one-way valve and the B one-way valve both include a valve tube and a channel ring arranged in the valve tube, a guide plate is installed at one end of the channel ring, and a guide column is slidably provided on the guide plate, a blocking plate is provided at one end of the guide column, and a spring is provided at the other end of the guide column and fastened by bolts.

[0014] Preferably, the diameter of the blocking plate is larger than the inner diameter of the channel ring and smaller than the inner diameter of the valve tube, and under the elasticity of the spring, the blocking plate blocks one end of the channel ring for unidirectional conduction.

[0015] Preferably, the filter box includes a box body and a drainage hood installed on the inner wall of the box body, the drainage hood is provided with a plurality of rotatable drainage tubes and a connecting shaft, and the connecting shaft and the plurality of drainage tubes are transmitted by gears, filter elements are installed on the plurality of drainage tubes, a fan blade is installed at one end of the connecting shaft, a guide tube extending to the interior of the box body is installed on the box body, and the fan blade is located in the guide tube, the A one-way valve is connected to the guide tube, and the drainage hood is connected to the oil tank through a pipeline.

[0016] Preferably, the guide pipe includes a conduit extending to the interior of the filter box, the interior of the conduit is provided with an injection channel, and a bracket is installed at one end of the conduit, and the connecting shaft is rotatably connected to the bracket, and the fan blades are located at one end of the injection channel inside the conduit, and the insulation is injected through the injection channel, so that the fan blades drive the connecting shaft to rotate, and under the transmission of the gears, all the filter elements rotate.

[0017] Preferably, the isolation structure includes an opening at the top of the oil tank, a sealing block is installed on the opening by bolts, and a rectangular frame is installed at the bottom end of the sealing block, a water-oil separation membrane is provided inside the rectangular frame, a U-shaped frame is installed inside the oil tank, and a slide groove is provided on the outer side of the rectangular frame, and the rectangular frame is in contact with the U-shaped frame to divide the oil tank into two parts, front and rear.

[0018] A method for regulating the gas pressure of an oil-immersed transformer, the specific operation is as follows:

[0019] S1. The air pressure inside the transformer increases. When the air pressure exceeds the setting, the strong thrust of the air pressure causes the A two-way pressure regulating valve to be turned on, and the insulating oil is introduced into the oil pipeline. Under this air pressure, the B one-way valve is turned on, and the A one-way valve is closed. The insulating oil is introduced into the filter box through the B one-way valve to separate the impurities in the insulating oil. At the same time, under the air pressure, the filtered insulating oil in the filter box is introduced into the oil tank through the pipeline. At this time, the air pressure in the oil tank increases, and the strong thrust of the air pressure causes the B two-way pressure regulating valve to be turned on, releasing the air pressure. When the air pressure inside the transformer returns to normal, the A two-way pressure regulating valve automatically closes. When the air pressure inside the oil tank returns to normal, the B two-way pressure regulating valve also automatically closes.

[0020] S2. When the air pressure inside the transformer becomes smaller and lower than the set value, the air pressure generates negative pressure adsorption force to turn on the A two-way pressure regulating valve and introduce it into the oil pipeline to generate negative pressure. At this time, the B one-way valve is closed and the A one-way valve is opened. The insulating oil in the oil tank that has passed through the isolation structure to complete oil-water separation is introduced into the oil pipeline through the A one-way valve and re-introduced into the transformer through the A two-way pressure regulating valve. After the air pressure inside the transformer returns to normal, the A two-way pressure regulating valve is automatically closed, and the air pressure in the oil tank becomes smaller. The air pressure generates negative pressure adsorption force to turn on the B two-way pressure regulating valve. After the air pressure inside the oil tank returns to normal, the B two-way pressure regulating valve is also automatically closed.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) Two-way pressure regulating valve A and two-way pressure regulating valve B are provided, which can automatically adjust in both directions according to the changes in the air pressure inside the transformer. When the air pressure increases or decreases, the valve body can be opened in time to allow the insulating oil to flow into or out of the transformer, ensuring that the air pressure inside the transformer is always within the appropriate range, effectively protecting the safe operation of the transformer. The two-way pressure regulating valve does not require power input, and can achieve pressure adjustment only by relying on the changes in the air pressure inside the transformer, which is energy-saving and environmentally friendly and reduces operating costs;

[0023] (2) Equipped with a filter box, when the air pressure inside the transformer increases and the oil is drained, the insulating oil can be filtered to remove impurities. The filter element on the drainage pipe rotates under the flow of the insulating oil, which not only reduces the adhesion of impurities, but also improves the filtering effect and prolongs the service life of the insulating oil;

[0024] (3) An isolation structure is installed inside the oil tank, which can effectively separate the water in the insulating oil through the water-oil separation membrane, ensuring the insulating oil injected into the transformer is of good quality and reducing the adverse effects of water on the transformer performance;

[0025] (4) The design of the A and B check valves can accurately control the flow direction of the insulating oil according to the changes in air pressure. Together with the A two-way pressure regulating valve, they can achieve one-way conduction of oil discharge and oil suction, ensuring the accuracy and reliability of operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the front view of the present invention;

[0027] Figure 2 This is a schematic diagram of the structure of a bidirectional pressure regulating valve A of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of a one-way valve A of the present invention;

[0029] Figure 4 This is a schematic diagram of the filter box structure of the present invention;

[0030] Figure 5 For the present invention Figure 4 Schematic diagram of the local structure;

[0031] Figure 6 This is a schematic diagram of the structure of the flow guide pipe of the present invention;

[0032] Figure 7 It is a schematic diagram of the isolation structure of the present invention.

[0033] In the figure: 1. oil tank; 2. A two-way pressure regulating valve; 21. valve body; 22. sealing ring; 23. guide plate; 24. boss; 25. adjusting nut; 26. threaded column; 27. piston; 28. reset spring; 3. oil pipeline; 4. A one-way valve; 41. valve pipe; 42. channel ring; 43. guide plate; 44. guide column; 45. blocking plate; 46. spring; 5. B one-way valve; 6. filter box; 61. box body; 62. drainage cover; 63. drainage pipe; 64. connecting shaft; 65. filter element; 66. fan blade; 67. guide pipe; 68. conduit; 69. injection channel; 610. bracket; 7. B two-way pressure regulating valve; 8. exhaust pipe; 9. isolation structure; 91. opening; 92. sealing block; 93. rectangular frame; 94. water-oil separation membrane; 95. U-shaped frame. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. In order to keep the following description of the embodiments of the present disclosure clear and concise, the present disclosure omits detailed descriptions of known functions and known components to avoid unnecessary confusion of the concepts of the present invention.

[0035] See also Figure 1 , an oil-immersed transformer gas pressure regulating device, comprising an oil tank 1 and a bidirectional pressure regulating valve A 2 installed on the top of the transformer, and the bidirectional pressure regulating valve A 2 is connected to the inside of the transformer, an oil delivery pipe 3 is installed on the top of the bidirectional pressure regulating valve A 2, and the oil delivery pipe 3 is connected to an A check valve 4 and a B check valve 5, and the A check valve 4 and the B check valve 5 have opposite conduction directions, the A check valve 4 is connected to the bottom end of the oil tank 1, the B check valve 5 is connected to a filter box 6, and the filter box 6 is connected to the oil tank 1 through a pipeline;

[0036] The air pressure inside the transformer increases, causing the insulating oil inside to be introduced into the oil pipeline 3 through the A two-way pressure regulating valve 2, and then introduced into the filter box 6 through the B one-way valve 5 for filtration, and then introduced into the oil tank 1 to store the discharged insulating oil.

[0037] The air pressure in the transformer decreases, and the insulating oil in the oil tank 1 is sucked into the oil pipeline 3 through the A one-way valve 4, and then introduced into the transformer through the A two-way pressure regulating valve 2, and the insulating oil stored in the oil tank 1 is sucked back into the transformer, thus reducing the consumption of insulating oil.

[0038] An exhaust hole is provided at the top of the oil tank 1, and a B two-way pressure regulating valve 7 is installed on the exhaust hole of the oil tank 1, and an L-shaped exhaust pipe 8 is installed at the top of the B two-way pressure regulating valve 7. The air pressure inside the oil tank 1 is adjusted by the B two-way pressure regulating valve 7. The injection and extraction of insulating oil in the oil tank 1 will cause the air pressure to change. Therefore, the B two-way pressure regulating valve 7 can automatically open and adjust the air pressure when the air pressure in the oil tank 1 changes.

[0039] See also Figure 2The A bidirectional pressure regulating valve 2 and the B bidirectional pressure regulating valve 7 both include a valve body 21 and a sealing ring 22 installed inside the valve body 21. Two bosses 24 located on both sides of the sealing ring 22 are installed inside the valve body 21, and guide plates 23 are installed on the two bosses 24. A slidable threaded column 26 is provided at the center of the two guide plates 23. The threaded column 26 has threads only at two ends, and a piston 27 located on the inner side of the sealing ring 22 is provided in the middle of the threaded column 26. A reset spring 28 and an adjusting nut 25 are provided at both ends of the threaded column 26. By adjusting the position of the nut 25, the reset spring 28 is compressed so that the piston 27 is located in the middle of the sealing ring 22. The inner diameter of the boss 24 is larger than the inner diameter of the sealing ring 22, so that the piston 27 can pass through the boss 24 and slide in the sealing ring 22. When the air pressure in the transformer increases or decreases, the air pressure pushes the piston 27 up and down. When the piston 27 is separated from the sealing ring 22, the valve body 21 is turned on to adjust the air pressure.

[0040] When the air pressure is high, the insulating oil of the A two-way pressure regulating valve 2 and the B two-way pressure regulating valve 7 can push open the piston 27, so that the piston 27 is separated from the sealing ring 22, so that the valve body 21 is conductive. When the air pressure is insufficient, the elasticity of the return spring 28 can make the piston 27 return to its original position to block the sealing ring 22, so that the valve body 21 is closed again;

[0041] When the air pressure of the A two-way pressure regulating valve 2 and the B two-way pressure regulating valve 7 is low, the insulating oil contracts and the air pressure decreases, generating negative pressure, which moves the piston 27 downward, so that the piston 27 is separated from the sealing ring 22, and the valve body 21 is opened. When the air pressure is restored, the elasticity of the return spring 28 can make the piston 27 return to its original position to block the sealing ring 22, so that the valve body 21 is closed again;

[0042] The guide plate 23 is installed on the boss 24 by bolts, and insulating oil can pass through the insulating oil, which makes it convenient to install the piston 27, and also convenient to install the reset spring 28 and the adjusting nut 25. The position of the adjusting nut 25 is adjusted by rotation, and the tightness of the reset spring 28 is adjusted so that the piston 27 can be conducted under a specific pressure, thereby adjusting the air pressure of the A two-way pressure regulating valve 2 and the B two-way pressure regulating valve 7.

[0043] A two-way pressure regulating valve 2 and B two-way pressure regulating valve 7 can adjust the air pressure in both directions, which can not only relieve pressure but also increase pressure. No electricity is required and the pressure can be adjusted by changing the air pressure inside the transformer.

[0044] See also Figure 3The A one-way valve 4 and the B one-way valve 5 both include a valve tube 41 and a channel ring 42 arranged in the valve tube 41, a conduction plate 43 is installed at one end of the channel ring 42, and a guide column 44 is slidably provided on the conduction plate 43, a blocking plate 45 is provided at one end of the guide column 44, and a spring 46 is provided at the other end of the guide column 44 and fastened by bolts, the diameter of the blocking plate 45 is larger than the inner diameter of the channel ring 42 and smaller than the inner diameter of the valve tube 41, and under the elasticity of the spring 46, the blocking plate 45 blocks one end of the channel ring 42 for one-way conduction.

[0045] When the pressure is released, the baffle plate 45 in the B check valve 5 is pushed open to complete the conduction, and the baffle plate 45 in the A check valve 4 is pushed against the channel ring 42 for sealing, so that the insulating oil is introduced into the filter box 6 through the B check valve 5 for filtration and then introduced into the oil tank 1. When the pressure is increased, the baffle plate 45 in the A check valve 4 is pushed open to complete the conduction, and the baffle plate 45 in the B check valve 5 is pushed against the channel ring 42 for sealing, so that the insulating oil in the oil tank 1 is sucked into the oil pipeline 3 through the A check valve 4, and is introduced into the transformer through the A two-way pressure regulating valve 2, and the oil discharge and unloading operations are completed between the oil tank 1 and the A two-way pressure regulating valve 2 through the A check valve 4 and the B check valve 5.

[0046] See also Figure 4 and Figure 5 The filter box 6 includes a box body 61 and a drainage cover 62 installed on the inner wall of the box body 61, and a plurality of rotatable drainage pipes 63 and a connecting shaft 64 are provided on the drainage cover 62, and the connecting shaft 64 and the plurality of drainage pipes 63 are transmitted by gears, and filter elements 65 are installed on the plurality of drainage pipes 63, and a fan blade 66 is installed at one end of the connecting shaft 64. A guide pipe 67 extending to the interior of the box body 61 is installed, and the fan blade 66 is located in the guide pipe 67, the A one-way valve 4 is connected to the guide pipe 67, and the drainage cover 62 is connected to the oil tank 1 through a pipeline.

[0047] There is usually a small amount of oil gas, foam and impurities on the surface of the insulating oil of the transformer. Therefore, when the transformer discharges oil through the A two-way pressure regulating valve 2, these substances will be discharged, and the insulating oil is introduced into the box body 61 through the guide pipe 67, driving the fan blade 66 to rotate, and the fan blade 66 will drive the connecting shaft 64 to rotate. Under the gear meshing, multiple drainage pipes 63 drive the filter element 65 to rotate, and the filter element 65 is used to filter the insulating oil to remove impurities in the insulating oil. The rotating filter element 65 stirs in the insulating oil to reduce the adhesion of impurities. When the liquid level of the insulating oil is lower than the filter element 65 and the A two-way pressure regulating valve 2 is also relieving pressure, the air pressure will cause the gas in the box body 61 to pass through the filter element 65 and be introduced into the oil tank 1 through the pipeline for exhaust.

[0048] See also Figure 6The guide pipe 67 includes a conduit 68 extending to the inside of the filter box 6, an injection channel 69 is provided inside the conduit 68, and a bracket 610 is installed at one end of the conduit 68, and the connecting shaft 64 is connected to the bracket 610, and the fan blade 66 is located at one end of the injection channel 69 inside the conduit 68, and the insulating oil is injected through the injection channel 69, so that the fan blade 66 drives the connecting shaft 64 to rotate, and under the transmission of the gear, all the filter elements 65 rotate, and the inside of the conduit 68 is narrowed by the injection channel 69, so that the insulating oil is injected after passing through the injection channel 69, driving the fan blade 66 to rotate quickly, so that the filter element 65 rotates, stirs in the insulating oil, and reduces the adhesion of impurities on the surface.

[0049] See also Figure 7 The oil tank 1 is provided with an isolation structure 9 for separating water from insulating oil, and the insulating oil A after water separation is led out by a one-way valve 4 and injected into the transformer. The isolation structure 9 includes an opening 91 opened at the top of the oil tank 1, a sealing block 92 is installed on the opening 91 by bolts, and a rectangular frame 93 is installed at the bottom end of the sealing block 92, a water-oil separation membrane 94 is provided inside the rectangular frame 93, a U-shaped frame 95 is installed inside the oil tank 1, and a slide groove is provided on the outer side of the rectangular frame 93, and the rectangular frame 93 and the U-shaped frame 95 can be sealed after contact, so as to divide the oil tank 1 into two parts, front and rear.

[0050] The insulating oil has the characteristic of absorbing water. At the same time, after the B two-way pressure regulating valve 7 is opened, the outside air will enter the oil tank 1, so that the insulating oil in the oil tank 1 absorbs the moisture in the air. In addition, the transformer itself will be in contact with the air, so there is a small amount of moisture in the insulating oil, but the moisture in the insulating oil cannot be too much. Therefore, the water in the insulating oil is separated by the water-oil separation membrane 94, so that the insulating oil can be guided out through the one-way valve 4 and enter the transformer. In this way, the moisture in the transformer insulating oil is slowly adjusted, and the isolation structure 9 is convenient for disassembly, replacement and removal.

[0051] An exhaust hole is provided at the top of the oil tank 1, and an oil-gas separator 10 is provided below the exhaust hole, that is, an oil-gas separation filter element is installed to intercept the insulating oil in the air to prevent the insulating oil from leaking in the form of gas.

[0052] A method for regulating the gas pressure of an oil-immersed transformer, the specific operation is as follows:

[0053] S1. The air pressure inside the transformer increases. When the air pressure exceeds the setting, the strong thrust of the air pressure causes the A two-way pressure regulating valve 2 to be turned on, and the insulating oil is introduced into the oil pipeline 3. Under this air pressure, the B one-way valve 5 is turned on, and the A one-way valve 4 is closed. The insulating oil is introduced into the filter box 6 through the B one-way valve 5 to separate the impurities in the insulating oil. At the same time, under the air pressure, the filtered insulating oil in the filter box 6 is introduced into the oil tank 1 through the pipeline. At this time, the air pressure in the oil tank 1 increases, and the strong thrust of the air pressure causes the B two-way pressure regulating valve 7 to be turned on, and the air pressure is released. When the air pressure inside the transformer returns to normal, the A two-way pressure regulating valve 2 is automatically closed. When the air pressure inside the oil tank 1 returns to normal, the B two-way pressure regulating valve 7 is also automatically closed.

[0054] S2. When the air pressure inside the transformer becomes smaller and lower than the set value, the air pressure generates a negative pressure adsorption force to turn on the A two-way pressure regulating valve 2 and introduce it into the oil pipeline 3 to generate negative pressure. At this time, the B one-way valve 5 is closed and the A one-way valve 4 is opened. The insulating oil in the oil tank 1 that has been separated from the oil and water by the isolation structure 9 is introduced into the oil pipeline 3 through the A one-way valve 4 and re-introduced into the transformer through the A two-way pressure regulating valve 2. After the air pressure inside the transformer returns to normal, the A two-way pressure regulating valve 2 is automatically closed, and the air pressure in the oil tank 1 becomes smaller. The air pressure generates a negative pressure adsorption force to turn on the B two-way pressure regulating valve 7. After the air pressure inside the oil tank 1 returns to normal, the B two-way pressure regulating valve 7 is also automatically closed.

[0055] The above embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.

Claims

1. An oil-immersed transformer gas pressure regulating device, characterized in that: The invention comprises an oil tank (1) and an A two-way pressure regulating valve (2) installed on the top of a transformer, wherein the A two-way pressure regulating valve (2) is connected to the inside of the transformer, an oil delivery pipe (3) is installed on the top of the A two-way pressure regulating valve (2), an A check valve (4) and a B check valve (5) are connected to the oil delivery pipe (3), and the A check valve (4) and the B check valve (5) have opposite conduction directions, the A check valve (4) is connected to the bottom of the oil tank (1), the B check valve (5) is connected to a filter box (6), and the filter box (6) is connected to the oil tank (1) through a pipeline; The gas pressure in the transformer increases, so that the insulating oil in the transformer is introduced into the oil delivery pipe (3) through the A two-way pressure regulating valve (2), and then introduced into the filter box (6) through the B one-way valve (5) for filtration, and then introduced into the oil tank (1); The air pressure in the transformer decreases, and the insulating oil in the oil tank (1) is sucked into the oil pipeline (3) through the A one-way valve (4), and then introduced into the transformer through the A two-way pressure regulating valve (2); The top of the oil tank (1) is provided with an exhaust hole, and an oil-gas separator (10) is provided below the exhaust hole. A B two-way pressure regulating valve (7) is installed on the exhaust hole of the oil tank (1), and an L-shaped exhaust pipe (8) is installed on the top of the B two-way pressure regulating valve (7), and the air pressure inside the oil tank (1) is adjusted by the B two-way pressure regulating valve (7); An isolation structure (9) for separating water from insulating oil is installed inside the oil tank (1), and the insulating oil A after the water is separated is led out through a one-way valve (4) and injected into the transformer.

2. The oil-immersed transformer gas pressure regulating device according to claim 1, characterized in that: The A bidirectional pressure regulating valve (2) and the B bidirectional pressure regulating valve (7) both comprise a valve body (21) and a sealing ring (22) installed inside the valve body (21); two bosses (24) located on both sides of the sealing ring (22) are installed inside the valve body (21); and guide plates (23) are installed on the two bosses (24); a slidable threaded column (26) is provided at the center of the two guide plates (23); and a piston (27) located inside the sealing ring (22) is provided in the middle of the threaded column (26); and a return spring (28) and an adjusting nut (25) are provided at both ends of the threaded column (26); and the return spring (28) is compressed by adjusting the position of the nut (25) so that the piston (27) is located in the middle of the sealing ring (22).

3. The oil-immersed transformer gas pressure regulating device according to claim 1, characterized in that: The inner diameter of the boss (24) is larger than the inner diameter of the sealing ring (22), so that the piston (27) can pass through the boss (24) and slide in the sealing ring (22). When the air pressure in the transformer increases or decreases, the air pressure pushes the piston (27) to move up and down. When the piston (27) is separated from the sealing ring (22), the valve body (21) is turned on to adjust the air pressure.

4. The oil-immersed transformer gas pressure regulating device according to claim 1, characterized in that: The A check valve (4) and the B check valve (5) both comprise a valve tube (41) and a channel ring (42) arranged in the valve tube (41); a guide plate (43) is mounted on one end of the channel ring (42); a guide column (44) is slidably arranged on the guide plate (43); a blocking plate (45) is arranged on one end of the guide column (44); and a spring (46) is arranged at the other end of the guide column (44) and is fastened by a bolt.

5. The oil-immersed transformer gas pressure regulating device according to claim 4, characterized in that: The diameter of the blocking plate (45) is larger than the inner diameter of the channel ring (42) and smaller than the inner diameter of the valve tube (41). Under the elasticity of the spring (46), the blocking plate (45) blocks one end of the channel ring (42) to achieve unidirectional conduction.

6. The oil-immersed transformer gas pressure regulating device according to claim 1, characterized in that: The filter box (6) comprises a box body (61) and a drainage cover (62) mounted on the inner wall of the box body (61); a plurality of rotatable drainage pipes (63) and a connecting shaft (64) are provided on the drainage cover (62); the connecting shaft (64) and the plurality of drainage pipes (63) are driven by gears; a filter element (65) is mounted on each of the plurality of drainage pipes (63); a fan blade (66) is mounted on one end of the connecting shaft (64); a drainage pipe (67) extending into the interior of the box body (61) is mounted on the box body (61); the fan blade (66) is located in the drainage pipe (67); the A one-way valve (4) is connected to the drainage pipe (67); and the drainage cover (62) is connected to the oil tank (1) via a pipeline.

7. The oil-immersed transformer gas pressure regulating device according to claim 6, characterized in that: The guide pipe (67) includes a conduit (68) extending to the inside of the filter box (6), an injection channel (69) is provided inside the conduit (68), and a bracket (610) is installed at one end of the conduit (68), and the connecting shaft (64) and the bracket (610) are connected to each other, and the fan blade (66) is located at one end of the injection channel (69) inside the conduit (68), and the insulation is injected through the injection channel (69), so that the fan blade (66) drives the connecting shaft (64) to rotate, and under the transmission of the gear, all the filter elements (65) rotate.

8. The oil-immersed transformer gas pressure regulating device according to claim 1, characterized in that: The isolation structure (9) comprises an opening (91) formed at the top of the oil tank (1), a sealing block (92) being mounted on the opening (91) by means of bolts, and a rectangular frame (93) being mounted at the bottom end of the sealing block (92), a water-oil separation membrane (94) being arranged inside the rectangular frame (93), a U-shaped frame (95) being mounted inside the oil tank (1), and a sliding groove being arranged on the outer side surface of the rectangular frame (93), and the rectangular frame (93) and the U-shaped frame (95) being in contact with each other to divide the oil tank (1) into two front and rear parts.

9. A method for regulating the air pressure of an oil-immersed transformer, characterized in that: The oil-immersed transformer gas pressure regulating device according to any one of claims 1 to 8 is used, and the specific operations are as follows: S1. The air pressure inside the transformer increases. When the air pressure exceeds the setting value, the strong thrust of the air pressure causes the A two-way pressure regulating valve (2) to be turned on, and the insulating oil is introduced into the oil pipeline (3). Under this air pressure, the B one-way valve (5) is turned on, and the A one-way valve (4) is closed. The insulating oil is introduced into the filter box (6) through the B one-way valve (5) to separate the impurities in the insulating oil. At the same time, under the air pressure, the filtered insulating oil in the filter box (6) is introduced into the oil tank (1) through the pipeline. At this time, the air pressure in the oil tank (1) increases. The strong thrust of the air pressure causes the B two-way pressure regulating valve (7) to be turned on, and the air pressure is released. When the air pressure inside the transformer returns to normal, the A two-way pressure regulating valve (2) is automatically closed. When the air pressure inside the oil tank (1) returns to normal, the B two-way pressure regulating valve (7) is also automatically closed. S2. When the air pressure inside the transformer decreases, when the air pressure is lower than the setting, the air pressure generates a negative pressure adsorption force to open the A two-way pressure regulating valve (2), and introduce it into the oil pipeline (3) to generate negative pressure. At this time, the B one-way valve (5) is closed, and the A one-way valve (4) is opened. The insulating oil in the oil tank (1) that has been separated from the oil and water by the isolation structure (9) is introduced into the oil pipeline (3) through the A one-way valve (4), and is re-introduced into the transformer through the A two-way pressure regulating valve (2). After the air pressure inside the transformer returns to normal, the A two-way pressure regulating valve (2) automatically closes, and the air pressure in the oil tank (1) decreases. The air pressure generates a negative pressure adsorption force to open the B two-way pressure regulating valve (7). After the air pressure inside the oil tank (1) returns to normal, the B two-way pressure regulating valve (7) also automatically closes.

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