Oil-immersed transformer

Abstract

An oil-immersed transformer includes an oil tank, an oil conservator located above the oil tank, a pressure balancing system, and a cooling system. The cooling system includes a heat dissipation plate assembly, two positioning tubes, a first connecting tube, and a second connecting tube. The inner space of the oil conservator and the inner channels of the two positioning tubes are connected through the first and second connecting tubes. The heat dissipation plate assembly includes a first heat dissipation seat, a second heat dissipation seat, two guide rods, and several sealing rings. The second heat dissipation seat slides on the first heat dissipation seat. The guide rods are installed on the second heat dissipation seat and inserted into the positioning tubes. The sealing rings are installed on the guide rods and sandwiched between the guide rods and the positioning tubes. The guide rods can be moved and adjusted on the positioning tubes. During operation, the pressure balancing system adjusts its state according to the oil level in the oil conservator, thereby using the air pressure in the oil conservator to adjust the position of the second heat dissipation seat. This invention effectively extends the transformer's lifespan, has strong practicality, and has significant potential for widespread application.

Description

Technical Field

[0001] This invention relates to a transformer, and more particularly to an oil-immersed transformer. Background Technology

[0002] Transformers are commonly used equipment in power systems, primarily for voltage transformation, power distribution, and transmission. Oil-immersed transformers are a type of transformer, specifically a liquid-cooled transformer where the windings and core are completely submerged in insulating oil (usually mineral oil or synthetic ester). The high insulation and heat dissipation capabilities of the oil ensure stable operation. Oil-immersed transformers dominate power systems due to their high capacity, low cost, and high reliability.

[0003] For oil-immersed transformers, especially small self-cooled oil-immersed transformers, corrugated heat sinks are usually installed on the outside of the tank to assist in heat dissipation. Corrugated heat sinks effectively increase the surface area in contact with air, thus improving heat dissipation. However, the structure of existing heat sinks in self-cooled oil-immersed transformers is fixed, and the heat dissipation area cannot be adjusted according to the transformer's operating power. Since heat dissipation in self-cooled transformers is mainly accomplished by the heat sinks, when the transformer is operating under high load, it generates a large amount of heat, which can easily lead to insufficient heat dissipation from the heat sinks, causing the transformer temperature to become too high, damaging transformer components, and reducing the transformer's service life. Summary of the Invention

[0004] Therefore, it is necessary to provide an oil-immersed transformer to address the shortcomings of existing technologies.

[0005] An oil-immersed transformer includes an oil tank, an oil conservator located above the oil tank, a pressure balancing system, and a cooling system. The cooling system includes a heat dissipation plate assembly, two positioning tubes, a first connecting tube, and a second connecting tube. The inner space of the oil conservator and the inner channels of the two positioning tubes are connected through the first and second connecting tubes. The heat dissipation plate assembly includes a first heat dissipation seat, a second heat dissipation seat, two guide rods, and several sealing rings. The second heat dissipation seat is slidably mounted on the first heat dissipation seat. The guide rods are mounted on the second heat dissipation seat and inserted into the positioning tubes. The sealing rings are mounted on the guide rods and clamped between the guide rods and the positioning tubes. The guide rods can be moved and adjusted on the positioning tubes. During operation, the pressure balancing system adjusts its state according to the liquid level in the oil conservator, thereby using the air pressure in the oil conservator to adjust the position of the second heat dissipation seat.

[0006] In one embodiment, the pressure balancing system includes an oil guide pipe and an electrically controlled valve. The two ends of the oil guide pipe are respectively connected to the oil tank and the oil reservoir, and the electrically controlled valve is connected to the oil tank through a pipe.

[0007] When the temperature of the insulating oil rises to the point where the liquid level of the insulating oil reaches the set value, the switch of the electrically controlled valve is closed. When the air pressure inside the oil tank increases further, the air pressure inside the oil tank pushes the guide rod and the second heat sink to move outward. When the air pressure inside the oil tank reaches the set value, the switch of the electrically controlled valve is reopened.

[0008] When the level of insulating oil inside the oil conservator drops to the set value, the switch of the electrically controlled valve is closed. As the temperature of the insulating oil continues to drop, the air pressure inside the oil conservator forms a negative pressure, pulling the guide rod and the second heat sink back to their original positions. When the air pressure inside the oil conservator is detected to have dropped to the set value, the switch of the electrically controlled valve is reopened.

[0009] In one embodiment, the air pressure balancing system further includes a control box, a pressure gauge, and a level gauge. The pressure gauge and level gauge are installed near the top of the oil tank. The pressure gauge is used to detect the air pressure inside the oil tank, and the level gauge is used to detect the liquid level of the insulating oil inside the oil tank. The pressure gauge, level gauge, and electrically controlled valve are all electrically connected to the control box. The pressure gauge and level gauge feed back the detection results to the control box, and the control box controls the operation of the electrically controlled valve.

[0010] In one embodiment, there are two sets of heat sink assemblies, and the guide rods of the two sets of heat sink assemblies are inserted into the positioning tube from the front and rear sides of the positioning tube, respectively.

[0011] In one embodiment, the number of heat sink assemblies is one set, and the end of the positioning tube away from the heat sink assemblies is in a closed state.

[0012] In one embodiment, the fuel tank includes a tank body and a cover disposed on the upper end face of the tank body. The tank body has a relatively large wide surface on the front and rear sides along the horizontal direction and a relatively small narrow surface on the left and right sides along the horizontal direction. The first heat sink is fixedly installed on the wide surface of the tank body, and two positioning tubes are respectively disposed on the outer sides of the two narrow surfaces of the tank body.

[0013] In one embodiment, the first heat sink includes a first main plate and a plurality of first heat sinks connected to one side of the first main plate; the second heat sink includes a second main plate and a plurality of second heat sinks connected to one side of the second main plate, and the second heat sink is further provided with a plurality of receiving grooves, the receiving grooves corresponding one-to-one with the second heat sinks, the receiving grooves extending inward into the interior of the second heat sinks, the first heat sinks corresponding one-to-one with the receiving grooves on the second heat sink, and the first heat sinks being inserted into the receiving grooves.

[0014] In one embodiment, the second heat sink is further provided with perforated holes on the second main body plate, and the perforated holes are distributed between the two second heat sinks.

[0015] In one embodiment, the outer peripheral surface of the guide rod is provided with a plurality of slots, the sealing ring is installed on the slots of the guide rod and extends out from the slot opening, and the sealing ring is sandwiched between the slots of the guide rod and the inner wall of the positioning tube.

[0016] In one embodiment, the heat sink assembly further includes several limiting members that pass through the second heat sink and are mounted on the housing. The limiting members guide and limit the second heat sink, allowing the second heat sink to be adjusted along the first heat sink within a certain horizontal distance.

[0017] The beneficial effects of the oil-immersed transformer of this invention are as follows: Based on the first heat sink, a second heat sink is further provided. The position of the second heat sink on the first heat sink is adjustable to change the heat dissipation area. The air pressure balancing system adjusts its state according to the liquid level in the oil conservator, and then uses the air pressure in the oil conservator to adjust the position of the second heat sink. When the transformer is under high load, the heat dissipation plate assembly increases the heat dissipation area, enhances cooling capacity, and prevents the oil temperature from becoming too high. When the transformer is under low load, the heat dissipation area decreases, reducing unnecessary heat dissipation losses, improving operating economy, and avoiding excessive cooling or overheating of the insulating oil. This transformer is particularly suitable for operating environments with significant load fluctuations, large diurnal temperature differences, and significant seasonal temperature variations, effectively extending the transformer's lifespan. It is highly practical and has significant potential for widespread application. Attached Figure Description

[0018] Figure 1 , Figure 2 These are schematic diagrams of the oil-immersed transformer of the present invention at different angles;

[0019] Figure 3 , Figure 4 This is a schematic diagram showing the connection of the oil tank, air pressure balance system, and cooling system at different angles in this invention;

[0020] Figure 5 This is a cross-sectional view of the positioning tube and guide rod in this invention when they are installed together, wherein the air pressure is in the state of driving the guide rod back to its original position;

[0021] Figure 6 This is a cross-sectional view of the positioning tube and guide rod in this invention when they are installed together, wherein the air pressure is in a state that drives the guide rod to move outward;

[0022] Figure 7 This is a schematic diagram of the structure of the first heat sink and the second heat sink in this invention;

[0023] Figure 8 for Figure 7 Enlarged view of part A in the middle circle. Detailed Implementation

[0024] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0025] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0027] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0029] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0030] Please see Figures 1 to 8 This invention provides an oil-immersed transformer, comprising an oil tank 10, an iron core (not shown) disposed within the oil tank 10, a primary winding (not shown) and a secondary winding (not shown) wound on the iron core, a support frame 40 and a bushing 30 mounted on the oil tank 10, an oil conservator 20 mounted on the support frame 40 and positioned above the oil tank 10, insulating oil filling the oil tank 10 and the oil conservator 20, a pressure balancing system 60 connected to the oil tank 10, and a cooling system 50 for auxiliary cooling of the insulating oil in the oil tank 10. The primary and secondary windings are led out from the bushing 30, and the insulating oil is filled from inside the oil conservator 20 through the pressure balancing system 60 to fill the entire interior of the oil tank 10. The pressure balancing system 60 controls the air pressure inside the oil conservator 20, thereby adjusting the state of the cooling system 50.

[0031] The oil tank 10 includes a tank body 11 and a cover 12 covering the upper surface of the tank body 11. The tank body 11 and the cover 12 together form a sealed space for storing the iron core and insulating oil. The tank body 11 is generally square in shape, with relatively large wide surfaces 111 on opposite sides along the horizontal direction and relatively small narrow surfaces 112 on opposite sides along the left and right direction. The support frame 40 and the sleeve 30 are installed on the cover 12. The oil conservator 20 is provided with an oil inlet 21 and a sealing plug (not shown in the figure), and the sealing plug seals the oil inlet 21.

[0032] The cooling system 50 includes at least one set of heat dissipation plate group 51, two positioning tubes 52, a first connecting tube 53, and a second connecting tube 54. The positioning tubes 52, the first connecting tube 53, and the second connecting tube 54 are all hollow tubular structures. The two positioning tubes 52 are respectively located on the outer side of the two narrow surfaces 112 on the housing 11, and the positioning tubes 52 are distributed along the front-back direction. The cooling system 50 also includes a fixing bracket 55 for fixing the positioning tubes 52. The fixing bracket 55 is installed and fixed on the narrow surface 112 of the housing 11. One end of the first connecting tube 53 is connected to the top position of the oil conservator 20, and the other end of the first connecting tube 53 is connected to one of the positioning tubes 52. The two ends of the second connecting tube 54 are respectively connected to the first connecting tube 53 and the other positioning tube 52. The inner space of the oil conservator 20 and the inner channels of the two positioning tubes 52 are connected through the first connecting tube 53 and the second connecting tube 54.

[0033] Each heat sink assembly 51 includes a first heat sink 511, a second heat sink 512, two guide rods 513, several sealing rings 514, and several limiting members 515. The second heat sink 512 is slidably mounted on the first heat sink 511. The guide rods 513 are mounted on the second heat sink 512 and inserted into the positioning tube 52. The sealing rings 514 are mounted on the guide rods 513 and sandwiched between the guide rods 513 and the positioning tube 52. The sealing rings 514 seal the air passage between the inside and outside of the positioning tube 52, and prevent air from entering. The guide rod 513 can be moved and adjusted on the positioning tube 52. The limiting member 515 passes through the second heat sink 512 and is installed on the housing 11. When the guide rod 513 is squeezed in the positioning tube 52, the second heat sink 512 is adjusted outward to increase the heat dissipation area of ​​the heat sink assembly 51. The limiting member 515 guides and limits the second heat sink 512, so that the second heat sink 512 can be adjusted along the first heat sink 511 within a certain distance in the horizontal direction, preventing the second heat sink 512 from falling off the first heat sink 511.

[0034] Specifically, the first heat sink 511 includes a first main plate 5111 and a plurality of first heat sinks 5112 connected to one side of the first main plate 5111, the first heat sinks 5112 being arranged side by side. The second heat sink 512 includes a second main plate 5121 and a plurality of second heat sinks 5122 connected to one side of the second main plate 5121, the second heat sinks 5122 being arranged side by side. The second heat sink 512 is also provided with a plurality of receiving grooves 5123, the receiving grooves 5123 corresponding one-to-one with the second heat sinks 5122, and the receiving grooves 5123 extending inward from the side of the second main plate 5121 away from the second heat sinks 5122 into the interior of the second heat sinks 5122.

[0035] The outer peripheral surface of the guide rod 513 is provided with several slots 5131. The two guide rods 513 on the heat sink assembly 51 are respectively installed on the second main plate 5121 on both sides facing away from the second heat sink 5122. One end of the limiting member 515 is provided with a limiting head 5151.

[0036] During assembly, the sealing ring 514 is installed on the slot 5131 of the guide rod 513 and extends out from the slot 5131. The first heat sink 511 is fixedly installed on the wide surface 111 of the housing 11. The two guide rods 513 on the heat sink assembly 51 are respectively inserted into the two positioning tubes 52. The sealing ring 514 is sandwiched between the slot 5131 of the guide rod 513 and the inner wall of the positioning tube 52. The first heat sink 5112 corresponds one-to-one with the receiving slot 5123 on the second heat sink 512. The first heat sink 5112 is inserted into the receiving slot 5123. The end of the limiting member 515 away from the limiting head 5151 passes through the second main plate 5121 and is fixed on the housing 11.

[0037] In addition, the second heat sink 512 is provided with a hollow hole 5124 on the second main body plate 5121. The hollow hole 5124 is distributed between the two second heat sinks 5122. By setting the hollow hole 5124, the weight of the second heat sink 512 can be reduced, making the second heat sink 512 easier to push. At the same time, when the second heat sink 512 is completely attached to the first heat sink 511 or opened outward, the heat dissipation effect of the first heat sink 511 is guaranteed.

[0038] In this embodiment, there are two sets of heat sink assemblies 51, and the guide rods 513 of the two sets of heat sink assemblies 51 are inserted into the positioning tube 52 from the front and rear sides respectively. In other embodiments, for low-power transformers, the number of heat sink assemblies 51 can also be set to one set. When there is only one set of heat sink assemblies 51, the end of the positioning tube 52 away from the heat sink assemblies 51 is in a closed state.

[0039] The pressure balancing system 60 includes an oil guide pipe 61, a pressure gauge 62, a level gauge 63, an emergency pressure relief valve 64, a breather 66, an electrically controlled valve 65, a first guide pipe 67, a second guide pipe 68, and a control box. The two ends of the oil guide pipe 61 are connected to the bottom of the oil conservator 20 and the top of the oil tank 10, respectively. The oil guide pipe 61 connects the sealed space inside the oil tank 10 and the inner space of the oil conservator 20. The pressure gauge 62 and the level gauge 63 are installed near the top of the oil conservator 20. The pressure gauge 62 is used to detect the air pressure inside the oil conservator 20, and the level gauge 63 is used to detect the liquid level of the insulating oil inside the oil conservator 20. The emergency pressure relief valve 64 is installed at the bottom of the oil conservator 20. When the emergency pressure relief valve 64 is opened, it can release the pressure of the insulating oil inside the oil conservator 20 in an emergency. One port of the electrically controlled valve 65 is connected to the top of the oil tank 20 through the first guide pipe 67, and the other port of the electrically controlled valve 65 is connected to the breather 66 through the second guide pipe 68. After the switch of the electrically controlled valve 65 is opened, the breather 66 is connected to the internal space of the oil tank 20.

[0040] In addition, pressure gauge 62, level gauge 63, emergency pressure relief valve 64, and electrically controlled valve 65 are all electrically connected to the control box. Pressure gauge 62 and level gauge 63 feed back the detection results to the control box, which then controls the operation of emergency pressure relief valve 64 and electrically controlled valve 65. The breather 66 contains a desiccant to absorb moisture and impurities, preventing moisture and impurities in the air from contacting the insulating oil and causing it to deteriorate.

[0041] The working process of the oil-immersed transformer of the present invention is described in detail below:

[0042] Oil is replenished to the oil tank 10 through the oil inlet 21 and the oil guide pipe 61 of the oil conservator 20, so that the insulating oil fills the inside of the oil tank 10 and the liquid level of the insulating oil in the oil conservator 20 reaches about 1 / 2. The oil inlet 21 is sealed with a sealing plug. Initially, the switch of the electric control valve 65 is in the open state, the second heat sink 512 is completely covered on the first heat sink 511, the liquid level gauge 63 detects the liquid level of the insulating oil, and the pressure gauge 62 detects the air pressure inside the oil conservator 20. During the operation of the transformer, the heat generated causes the insulating oil to expand, and the insulating oil in the oil tank 10 is injected back into the oil conservator 20, and the liquid level of the insulating oil in the oil conservator 20 rises.

[0043] When the temperature of the insulating oil rises to the set value, causing the oil level to reach the set value, the control box closes the switch of the electrically controlled valve 65. As the temperature of the insulating oil continues to rise, the air pressure inside the oil conservator 20 increases. This air pressure acts on the guide rod 513 through the internal channels of the first connecting pipe 53, the second connecting pipe 54, and the positioning pipe 52, thereby pushing the guide rod 513 and the second heat sink 512 outward. This increases the area of ​​the second heat sink 512 and the first heat sink 511 exposed to the air, improving the heat dissipation effect. When the second heat sink 512 is moved to the limit head 5151 of the limiting member 515, the air pressure inside the conservator cannot be released, causing it to increase. When the pressure gauge 62 detects that the air pressure inside the oil conservator 20 has reached the set value, the control box reopens the switch of the electrically controlled valve 65 to release the air pressure.

[0044] When the level of insulating oil inside the oil tank 20 rises to the warning value, the control box opens the emergency pressure relief valve 64, allowing the insulating oil inside the oil tank 20 to flow out from the emergency pressure relief valve 64 for emergency pressure relief.

[0045] When the second heat sink 512 is in the outward-opening state and the temperature of the insulating oil begins to drop, the level of the insulating oil inside the oil conservator 20 drops to the set value. When this level drops, the control box closes the switch of the electric control valve 65. As the temperature of the insulating oil continues to drop, a negative pressure is formed inside the oil conservator 20. Under the action of the negative pressure inside the oil conservator 20, the guide rod 513 and the second heat sink 512 are pulled back to their original positions, so that the second heat sink 512 is completely attached to the first heat sink 511. When the air pressure inside the conservator further decreases, the pressure gauge 62 detects that the air pressure inside the oil conservator 20 has dropped to the set value. When this happens, the control box reopens the switch of the electric control valve 65 to maintain the air pressure balance inside and outside the oil tank 10.

[0046] The beneficial effects of the oil-immersed transformer of this invention are as follows: Based on the first heat sink 511, a second heat sink 512 is further provided. The position of the second heat sink 512 on the first heat sink 511 is adjustable to change the heat dissipation area. The air pressure balance system 60 adjusts its state according to the liquid level in the oil conservator 20, and then uses the air pressure in the oil conservator 20 to adjust the position of the second heat sink 512. When the transformer is under high load, the heat dissipation plate assembly 51 increases the heat dissipation area, enhances cooling capacity, and prevents the oil temperature from becoming too high. When the transformer is under low load, the heat dissipation area decreases, reducing unnecessary heat dissipation losses, improving operating economy, and avoiding excessive cooling or heating of the insulating oil. This transformer is particularly suitable for operating environments with significant load fluctuations, large diurnal temperature differences, and significant seasonal temperature variations, effectively extending the transformer's lifespan. It is highly practical and has significant potential for widespread application.

[0047] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0048] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An oil-immersed transformer, comprising an oil tank, an oil conservator disposed above the oil tank, a pressure balancing system, and a cooling system, characterized in that, The cooling system includes a heat dissipation plate assembly, two positioning tubes, a first connecting tube, and a second connecting tube. The inner space of the oil conservator and the inner channels of the two positioning tubes are connected through the first connecting tube and the second connecting tube. The heat dissipation plate assembly includes a first heat dissipation seat, a second heat dissipation seat, two guide rods, and several sealing rings. The second heat dissipation seat is slidably mounted on the first heat dissipation seat. The guide rods are mounted on the second heat dissipation seat and inserted into the positioning tubes. The sealing rings are mounted on the guide rods and clamped between the guide rods and the positioning tubes. The guide rods can be moved and adjusted on the positioning tubes. During operation, the air pressure balance system adjusts its state according to the liquid level in the oil conservator, and then uses the air pressure in the oil conservator to adjust the position of the second heat dissipation seat. The pressure balancing system includes an oil guide pipe and an electrically controlled valve. The two ends of the oil guide pipe are connected to the oil conservator and the oil tank, respectively. The electrically controlled valve is connected to the oil conservator through a pipe. The pressure balancing system also includes a control box, a pressure gauge, and a level gauge. The pressure gauge and level gauge are installed near the top of the oil conservator. The pressure gauge is used to detect the air pressure inside the oil conservator, and the level gauge is used to detect the liquid level of the insulating oil inside the oil conservator. The pressure gauge, level gauge, and electrically controlled valve are all electrically connected to the control box. The pressure gauge and level gauge feed back the detection results to the control box, and the control box controls the operation of the electrically controlled valve. When the temperature of the insulating oil rises to the point where the liquid level of the insulating oil reaches the set value, the switch of the electrically controlled valve is closed. When the air pressure inside the oil tank increases further, the air pressure inside the oil tank pushes the guide rod and the second heat sink to move outward. When the air pressure inside the oil tank reaches the set value, the switch of the electrically controlled valve is reopened. When the level of insulating oil inside the oil conservator drops to the set value, the switch of the electrically controlled valve is closed. As the temperature of the insulating oil continues to drop, the air pressure inside the oil conservator forms a negative pressure, pulling the guide rod and the second heat sink back to their original positions. When the air pressure inside the oil conservator is detected to have dropped to the set value, the switch of the electrically controlled valve is reopened.

2. The oil-immersed transformer according to claim 1, characterized in that, The number of heat dissipation plate assemblies is two sets, and the guide rods of the two sets of heat dissipation plate assemblies are inserted into the positioning tube from the front and rear sides of the positioning tube respectively.

3. The oil-immersed transformer according to claim 1, characterized in that, The number of heat sink assemblies is one set, and the end of the positioning tube away from the heat sink assemblies is in a closed state.

4. The oil-immersed transformer according to claim 1, characterized in that, The oil tank includes a tank body and a tank cover on the upper surface of the tank body. The tank body has a relatively large wide surface on the front and back sides along the horizontal direction and a relatively small narrow surface on the left and right sides along the horizontal direction. The first heat sink is fixedly installed on the wide surface of the tank body, and two positioning tubes are respectively set on the outer side of the two narrow surfaces of the tank body.

5. The oil-immersed transformer according to claim 1, characterized in that, The first heat sink includes a first main plate and a plurality of first heat sinks connected to one side of the first main plate; the second heat sink includes a second main plate and a plurality of second heat sinks connected to one side of the second main plate. The second heat sink is also provided with a plurality of receiving slots, each receiving slot corresponding to a second heat sink. The receiving slots extend inward into the interior of the second heat sinks. The first heat sinks correspond one-to-one with the receiving slots on the second heat sink, and the first heat sinks are inserted into the receiving slots.

6. The oil-immersed transformer according to claim 5, characterized in that, The second heat sink is also provided with perforated holes on the second main body plate, and the perforated holes are distributed between the two second heat sinks.

7. The oil-immersed transformer according to claim 1, characterized in that, The outer circumferential surface of the guide rod is provided with several slots, and the sealing ring is installed on the slots of the guide rod and extends out from the slot opening. The sealing ring is sandwiched between the slots of the guide rod and the inner wall of the positioning tube.

8. The oil-immersed transformer according to claim 1, characterized in that, The heat sink assembly also includes several limiting members. The limiting members pass through the second heat sink and are installed on the housing. The limiting members guide and limit the second heat sink, so that the second heat sink can be adjusted along the first heat sink within a certain distance in the horizontal direction.

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