Oil-immersed transformer

Abstract

The application relates to an oil-immersed transformer, which comprises a shell assembly, an accommodating cavity is formed in the shell assembly, and the accommodating cavity is filled with a liquid insulation medium; a working device is arranged in the accommodating cavity; an expansion device is arranged in the shell assembly and / or the working device, and the expansion device is located below the liquid level of the liquid insulation medium, and the expansion device can be controlled to switch between an expansion state and a contraction state. Thus, the oil-immersed transformer controls the liquid level of the liquid insulation medium by switching the expansion device between the contraction state and the expansion state, so that the oil-immersed transformer does not need to be filled with too much liquid insulation medium, the weight of the oil-immersed transformer is reduced, the problem of overweight of the oil-immersed transformer is avoided, the adaptability of the oil-immersed transformer is improved, and the production manufacturing cost of the oil-immersed transformer is reduced.

Description

Technical Field

[0001] This application relates to the field of transformer technology, and in particular to an oil-immersed transformer. Background Technology

[0002] Oil-immersed transformers use transformer oil as the core insulating medium. During startup, the minimum oil level inside the transformer must be higher than the highest point of the transformer body and the bushing tail, ensuring effective insulation and heat dissipation for the internal components. However, in recent years, as oil-immersed transformers are used in increasingly demanding real-world environments, limitations in space and weight have arisen. The significant weight of the transformer oil inside an oil-immersed transformer can easily lead to overweight issues. Summary of the Invention

[0003] Therefore, it is necessary to provide an oil-immersed transformer to address the problem of overweight in oil-immersed transformers.

[0004] An oil-immersed transformer, comprising:

[0005] The housing assembly has an internal cavity filled with a liquid insulating medium.

[0006] The working device is disposed within the receiving cavity;

[0007] An expansion member is disposed on the housing assembly and / or the working device, and the expansion member is located below the liquid surface of the liquid insulating medium. The expansion member can be controllably switched between an expanded state and a contracted state. During the process of switching from the contracted state to the expanded state, the volume of the expansion member increases, and when the expansion member switches from the expanded state to the contracted state, the volume of the expansion member decreases.

[0008] In one embodiment, the expander can be controlled to inflate or deflate, and when the expander is inflated, it switches from the contracted state to the inflated state, and when the expander deflates, it switches from the inflated state to the contracted state.

[0009] In one embodiment, the oil-immersed transformer further includes an inflation component, which is disposed on the housing assembly, and the housing assembly is provided with a main exhaust valve and an inflation pipeline, the inflation pipeline connecting the expansion component and the inflation component, and the main exhaust valve connecting the expansion component and the external atmosphere.

[0010] In one embodiment, the oil-immersed transformer further includes an oil conservator and a control device. The oil conservator is disposed on the top of the housing assembly, and an oil storage chamber communicating with the working chamber is formed inside the oil conservator. An oil level sensor assembly is disposed inside the oil storage chamber. The oil level sensor assembly is communicatively connected to the control device, and the control device is communicatively connected to the air filling component and the main exhaust valve.

[0011] In one embodiment, the oil level sensor assembly includes a first oil level monitor, a second oil level monitor, and a third oil level monitor arranged sequentially along the direction of gravity, all of which are communicatively connected to the control device.

[0012] In one embodiment, a fixing hook is provided on the bottom wall of the receiving cavity, and a hanging part is provided on the expansion member, the hanging part being hung on the fixing hook.

[0013] In one embodiment, the oil-immersed transformer further includes a baffle plate, which is disposed on the side of the expansion member facing the liquid surface of the liquid insulating medium when the expansion member is in the expanded state.

[0014] In one embodiment, a gas detector is provided on the baffle, which is used to detect the gas inside the expansion member and issue an alarm signal.

[0015] In one embodiment, the oil-immersed transformer further includes an oil conservator, which has an oil storage chamber and a breather valve connecting the oil storage chamber to the outside atmosphere.

[0016] The baffle has an exhaust hole on the side facing the expansion member, and the housing assembly has an exhaust passage that connects the exhaust hole and the oil storage chamber.

[0017] In one embodiment, the baffle includes a first baffle and a second baffle that are perpendicular to each other. The first baffle is connected to the expansion member, and when the expansion member is in the expanded state, the second baffle is in contact with the side wall of the receiving cavity, and the second baffle is located on the side of the first baffle away from the expansion member.

[0018] The aforementioned oil-immersed transformer controls the liquid level of the insulating medium by switching the expansion element between a contracted and expanded state. This reduces the need for excessive liquid insulating medium inside the transformer, thus reducing its weight and preventing overweight issues. This improves the adaptability of the oil-immersed transformer and lowers its manufacturing costs. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of an oil-immersed transformer in some embodiments of this application.

[0020] Figure 2 for Figure 1 A schematic diagram of the internal structure of the oil-immersed transformer in the embodiment.

[0021] Figure 3 for Figure 2 A schematic diagram of the expansion member and baffle in the embodiment.

[0022] Figure 4 for Figure 2 A schematic diagram of the expansion member and baffle from another perspective in the embodiment.

[0023] Figure 5 for Figure 4 A schematic diagram of the structure when the expansion component contracts.

[0024] Figure 6 for Figure 5 Enlarged view at point A.

[0025] Figure 7 for Figure 1 A schematic diagram of the internal structure of the oil storage tank in the embodiment.

[0026] Figure 8 This is a schematic diagram illustrating the working process of an oil-immersed transformer in some embodiments of this application.

[0027] Explanation of reference numerals in the attached figures:

[0028] Housing assembly 10; receiving cavity 11; fixing hook 12; fixing plate 13;

[0029] Working device 20;

[0030] Expansion part 30; hanging part 31; baffle 32; first baffle 33; second baffle 34;

[0031] Inflation component 40; Main exhaust valve 41; Quick exhaust valve 42; Inflation piping 43;

[0032] Oil tank 50; control device 51; oil level sensor assembly 52; first oil level monitor 53; second oil level monitor 54; third oil level monitor 55; first signal line bracket 56; second signal line bracket 57; third signal line bracket 58; oil storage chamber 59. Detailed Implementation

[0033] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are 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 this application. However, this application can be implemented 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 this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0034] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application.

[0035] Furthermore, where the terms "first" and "second" appear, these terms are 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 with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0036] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," 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 expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0037] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" 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. Similarly, "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.

[0038] It should be noted that if 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. If 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. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0039] See Figure 1 and Figure 2 An embodiment of this application provides an oil-immersed transformer, including a housing assembly 10 and a working device 20 disposed within the housing assembly 10. The working device 20 refers to the windings and core of the oil-immersed transformer. The housing assembly 10 includes a receiving cavity 11, within which the working device 20 is disposed. The receiving cavity 11 is filled with a liquid insulating medium, which immerses the windings and core, providing insulation and heat dissipation to ensure long-term stable operation of the windings and core. The liquid insulating medium can be transformer oil such as mineral oil or vegetable oil. Liquid insulating media are chemically stable, have excellent insulation properties, and good thermal conductivity, allowing them to quickly conduct the heat generated by the windings and core to the housing assembly 10, and then dissipate it into the environment through the housing, thereby keeping the overall operating temperature of the oil-immersed transformer within a reasonable range.

[0040] In actual use, during startup, the minimum oil level of the liquid insulating medium inside the oil-immersed transformer needs to be higher than critical locations such as the highest point of the transformer body and the bushing tail to ensure the insulation and heat dissipation of the internal working components 20. Therefore, it is necessary to ensure that the amount of liquid insulating medium inside the transformer is sufficient to meet the insulation and heat dissipation requirements of the working components 20. However, this can easily lead to a large overall weight of the oil-immersed transformer, resulting in overweight issues.

[0041] Furthermore, during operation, the liquid insulating medium inside the oil-immersed transformer expands due to heat, causing the oil level to rise. In actual use, if the oil level inside the casing assembly 10 is too high, the liquid insulating medium will leak from the transformer's breather to the outside, causing oil leakage. Therefore, the highest oil level of the liquid insulating medium inside the oil-immersed transformer should be lower than the highest point inside the oil conservator 50 to ensure sufficient buffer space within the conservator 50 after the transformer oil expands due to heat.

[0042] Based on the above requirements, the amount of liquid insulating medium in an oil-immersed transformer cannot be too much or too little. At the same time, the size and total weight of the oil-immersed transformer must also be taken into account. This makes it difficult to balance the amount of liquid insulating medium in the oil-immersed transformer to meet all the requirements of the oil-immersed transformer.

[0043] Therefore, the oil-immersed transformer also includes an expansion member 30, which is disposed on the housing assembly 10 or the working device 20, and the expansion member 30 is located below the liquid surface of the liquid insulating medium. The expansion member 30 can be controlled to switch between an expanded state and a contracted state. During the process of switching from the contracted state to the expanded state, the volume of the expansion member 30 increases, and when the expansion member 30 switches from the expanded state to the contracted state, the volume of the expansion member 30 decreases.

[0044] Specifically, when the expansion member 30 switches from a contracted state to an expanded state, its volume increases. Since the expansion member 30 is located below the surface of the liquid insulating medium, the increased volume of the expansion member 30 repels the liquid insulating medium, causing the liquid level to rise. Conversely, when the expansion member 30 switches from an expanded state to a contracted state, its volume decreases, reducing its repulsion of the liquid insulating medium, causing the liquid level to drop.

[0045] The aforementioned oil-immersed transformer allows for adjustment of the liquid insulating medium level by switching the expansion element 30 between a contracted and expanded state. During startup, the expansion element 30 is switched to the expanded state, raising the liquid insulating medium level above the working device 20 to ensure proper heat dissipation. After the transformer has operated for a period, the liquid matrix expands due to heat; at this point, the expansion element 30 can be switched to the contracted state to lower the liquid insulating medium level and prevent oil leakage.

[0046] Thus, the above-mentioned oil-immersed transformer controls the liquid level of the liquid insulating medium by switching between the expansion member 30 in a contracted state and an expanded state. This allows the oil-immersed transformer to be filled with less liquid insulating medium, thereby reducing its weight and preventing it from becoming overweight. This improves the adaptability of the oil-immersed transformer and reduces its manufacturing cost.

[0047] In some embodiments of this application, the expansion member 30 can be controlled to inflate or deflate. When the expansion member 30 is inflated, it switches from a contracted state to an expanded state; when it deflates, it switches from an expanded state to a contracted state. Thus, by controlling the inflation or deflation of the expansion member 30, its expansion volume can be controlled, thereby achieving the effect of controlling the liquid level of the liquid insulating medium. Optionally, the expansion member 30 is made of high-quality oil-resistant rubber, which can prevent air leakage under pressures of 50-100 kPa.

[0048] It is understood that in other embodiments, the expansion member 30 can also expand and contract mechanically. For example, an expandable or retractable frame can be provided inside the expansion member 30, and an elastic skin can be provided on the outside, similar to an umbrella structure. When the frame is expanded, the volume of the expansion member 30 increases and it is in an expanded state; conversely, when the frame is retracted, the volume of the expansion member 30 decreases and it is in a contracted state. It is understood that the structure of the expansion member 30 is not limited to the above, as long as the expansion member 30 can expand or contract.

[0049] In some embodiments, to achieve inflation and deflation of the inflator 30, see [reference]. Figure 1 and Figure 2 The oil-immersed transformer also includes an inflation component 40, which is mounted on the housing assembly 10 via an inflation bracket. The housing assembly 10 is equipped with a main exhaust valve 41 and an inflation pipeline 43. The inflation pipeline 43 connects the expansion component 30 and the inflation component 40, while the main exhaust valve 41 connects the expansion component 30 to the external atmosphere. Thus, when the expansion component 30 needs to be inflated, it can be inflated through the inflation component 40 and the inflation pipeline 43, causing the expansion component 30 to expand. Conversely, when the expansion component 30 needs to be deflated, the main exhaust valve 41 can be opened to release the gas inside the expansion component 30 into the atmosphere, causing the inflation component 40 to contract.

[0050] Furthermore, in case of an emergency, such as a sudden and rapid increase in the temperature of the working component 20, causing a rapid rise in the temperature of the liquid insulating medium and a rapid expansion of its volume, ultimately leading to a rapid rise in the liquid level, a quick-release valve 42 is provided on the housing assembly 10 to prevent oil leakage in the oil-immersed transformer. When it is necessary to urgently lower the liquid level of the insulating medium, the main vent valve 41 and the quick-release valve 42 can be opened simultaneously to quickly release air from the expansion component 30, thereby rapidly lowering the liquid level of the insulating medium.

[0051] Optionally, both the main exhaust valve 41 and the quick exhaust valve 42 are located on the side wall of the receiving cavity 11. Specifically, the main exhaust valve 41 and the quick exhaust valve 42 can be fixed to the side wall of the receiving cavity 11 by means of flanges or welding, and the main exhaust valve 41 and the quick exhaust valve 42 are located at a position slightly above the center of the inflation component 40. Furthermore, the inflation component 40 is fixed to the outer wall of the housing assembly 10 by means of fixing bolts and welding.

[0052] In actual use, when the expander 30 is in an expanded state, the buoyancy of the expander 30 increases due to its increased volume. To prevent the expander 30 from moving upwards and floating out of the liquid surface, or from detaching from the connection between the expander 30 and the inflation pipe or exhaust valve, certain embodiments of this application refer to... Figure 3 and Figure 4 A fixed hook 12 is provided on the bottom wall of the cavity 11, and a hanging part 31 is provided on the expansion member 30. The hook part is hung on the fixed hook 12 so that the fixed hook 12 hooks the hanging part 31 to prevent the expansion member 30 from moving upward. This prevents the expansion member 30 from remaining below the liquid surface of the liquid insulating matrix after expansion, and also prevents movement that could cause the connection between the expansion member 30 and the inflation pipe or exhaust valve to detach.

[0053] In some specific embodiments, the fixed hooks 12 include multiple types, and the hanging parts 31 on the expansion member 30 also include multiple types. The multiple fixed hooks 12 and multiple hanging parts 31 correspond one-to-one and are hung on each other. The expansion member 30 can be determined according to the spatial shape of the internal cavity 11 of the housing assembly 10. Through the cooperation of the multiple hanging parts 31 and multiple fixed hooks 12, the expansion member 30 can be evenly stressed, preventing damage to the expansion member 30. Optionally, the expansion member 30 is strip-shaped, and the multiple fixed hooks 12 and multiple hanging parts 31 are arranged sequentially along the length of the expansion member 30. The spacing between them is 50-200 mm.

[0054] In some embodiments of this application, the oil-immersed transformer further includes a baffle 32. When the expansion member 30 is in an expanded state, the baffle 32 is located on the side of the expansion member 30 facing the liquid surface of the liquid insulating medium. In actual use, if there are defects on the expansion member 30, or if the expansion member 30 ages and cracks due to long-term use, the gas inside the expansion member 30 will leak to the outside of the expansion member 30 through the defects or cracks when it is in an expanded state. When the gas passes through the coil or lead area in the working device 20, the gas will cause the coil or lead to discharge, which may lead to a fire hazard in the oil-immersed transformer.

[0055] By installing a baffle 32 on the side of the expansion member 30 facing the liquid surface, when gas leakage occurs in the expansion member 30, the gas will float to the surface in the liquid insulating medium and eventually hit the baffle 32. The baffle 32 then confines the gas, preventing it from entering the coil or lead area within the working device 20, thereby reducing gas-induced discharge and ultimately reducing the safety hazard of fire in the oil-immersed transformer. Optionally, the area of ​​the baffle 32 is greater than or equal to the area of ​​the expansion member 30 in its expanded state; that is, the baffle 32 can completely cover the top of the expansion member 30, ensuring that all leaked gas is contained by the baffle 32.

[0056] Furthermore, a gas detector is also installed on the baffle 32. The gas detector is used to detect the gas inside the expansion member 30 and issue an alarm signal. The working status of the expansion member 30 is monitored by the gas detector. Once a gas leak is detected in the expansion member 30, the gas detector will issue an alarm signal. Based on the alarm signal, the oil-immersed transformer can perform a trip operation to cut off the current in the working device 20 and avoid damaging the operation of the transformer.

[0057] Furthermore, the oil-immersed transformer also includes an oil conservator 50, which contains an oil storage chamber 59 and a breather valve connecting the oil storage chamber 59 to the outside atmosphere. An exhaust port is provided on the side of the baffle 32 facing the expansion member 30, and an exhaust passage is provided on the housing assembly 10, connecting the exhaust port and the oil storage chamber 59. Thus, gas trapped by the baffle 32 enters the exhaust passage through the exhaust port, then enters the oil storage chamber 59 through the exhaust passage, and finally exits into the atmosphere through the breather valve on the oil storage chamber 59. This timely discharge of leaked gas prevents gas from accumulating on the baffle 32 and overflowing into the working device 20, thus affecting the normal operation of the oil-immersed transformer.

[0058] In some embodiments of this application, see [reference] Figure 5 and Figure 6The baffle 32 includes a first baffle 33 and a second baffle 34 arranged perpendicularly to each other. The first baffle 33 is connected to the expansion member 30. The connection can be made by bonding or by fixing with fasteners such as bolts, as long as the first baffle 33 can be fixed to and fit against the surface of the expansion member 30. When the expansion member 30 is in the expanded state, the second baffle 34 fits against the side wall of the receiving cavity 11, and the second baffle 34 is located on the side of the first baffle 33 away from the expansion member 30. That is, the baffle 32 is generally L-shaped, and by fitting against the side wall of the receiving cavity 11 through the second baffle 34, the baffle 32 can be prevented from folding upwards, thereby limiting the baffle 32 from floating upwards under the action of buoyancy.

[0059] During the process of the expansion member 30 switching from the expanded state to the contracted state, since the first stop 33 is connected to the expansion member 30, the first stop 33 will move downward as the expansion member 30 contracts, causing the second stop 34 to fold relative to the side wall of the receiving cavity 11. Until the expansion member 30 switches to the contracted state, the first stop 33 can cooperate with the inner wall of the receiving cavity 11 to clamp the expansion member 30.

[0060] Specifically, the housing assembly 10 includes a fixing plate 13. One side surface of the fixing plate 13 forms a side wall of a receiving cavity 11. The fixing plate 13 is a flat steel plate with bolt holes that mate with fixing bolts for fixing the inflatable component 40. The fixing plate 13 is connected to the side of the inflatable component 30 by adhesive bonding, so that the inflatable component 30 will not detach from the fixing plate 13 during inflation. Furthermore, during inflation, the angle formed between the first stop 33 of the baffle 32 and the fixing plate 13 gradually increases until the inflatable component 30 is in a collision state, at which point the first stop 33 is perpendicular to the fixing plate 13, and the fixing plate 13 and the second stop 34 are in contact with each other to restrict the baffle 32 from floating under the action of buoyancy.

[0061] In some embodiments of this application, see [reference] Figure 1 and Figure 7 The oil-immersed transformer also includes an oil conservator 50 and a control device 51. The oil conservator 50 is located on top of the housing assembly 10, and an oil storage chamber 59 communicating with the working chamber is formed within the oil conservator 50. An oil level sensor assembly 52 is installed in the oil storage chamber 59, and the oil level sensor assembly 52 is communicatively connected to the control device 51. The control device 51 is also communicatively connected to the air filling component 40, the main exhaust valve 41, and the quick exhaust valve 42. Furthermore, since the working chamber and the oil storage chamber 59 are connected, and the oil storage chamber 59 is located at the top of the working chamber, the liquid level of the liquid insulating medium in both the working chamber and the oil storage chamber 59 is mainly concentrated in the oil storage chamber 59. Therefore, the liquid level of the liquid insulating medium throughout the entire oil-immersed transformer can be monitored using the oil level sensor.

[0062] Furthermore, the data monitored by the oil level sensor assembly 52 is transmitted to the control device 51. The control device 51 controls the operation of the inflation component 40, the main exhaust valve 41, and the quick exhaust valve 42 based on the monitoring data of the oil level sensor assembly 52. ​​Specifically, when the oil level sensor assembly 52 detects that the liquid insulating medium level in the oil storage chamber 59 is low, the control device 51 can control the inflation component 40 to inflate the expansion component 30 to raise the liquid insulating medium level. Conversely, when the oil level sensor assembly 52 detects that the liquid insulating medium level in the oil storage chamber 59 is high, the control device 51 can control the main exhaust valve 41 or the quick exhaust valve 42 to operate to vent the expansion component 30, thereby lowering the liquid insulating medium level.

[0063] In some embodiments, the oil level sensor assembly 52 includes a first oil level monitor 53, a second oil level monitor 54, and a third oil level monitor 55 arranged sequentially along the direction of gravity. All three monitors are communicatively connected to the control device 51. Specifically, the first oil level monitor 53 is positioned highest, the second oil level monitor 54 is positioned in the middle, and the third oil level monitor 55 is positioned lowest. When the liquid insulating medium reaches the positions of the first oil level monitor 53, the second oil level monitor 54, and the third oil level monitor 55, they respectively output signals to the control device 51 to control the operation of the inflation component 40, the main control valve, and the quick exhaust valve 42.

[0064] Furthermore, the housing assembly 10 is also provided with a first signal line bracket 56, a second signal line bracket 57, and a third signal line bracket 58, so that the three signal lines of the control device 51 and the inflation component 40, the main exhaust valve 41, and the quick exhaust valve 42 can be respectively laid on the second signal line bracket 57 and the third signal line bracket 58, while the signal lines of the first oil level monitor 53, the second oil level monitor 54, and the third oil level monitor 55 and the control device 51 can be laid on the first signal line bracket 56.

[0065] In actual use, before each start-up of the oil-immersed transformer, the purging component 40 starts purging in advance. When the liquid insulating medium level reaches the position of the third oil level monitor 55, purging continues for a period of time and then stops. During the transformer startup process, the heat causes the liquid level to rise. When the liquid insulating medium level reaches the position of the second oil level monitor 54, the main vent valve 41 starts and runs for a period of time. This step is repeated before the oil-immersed transformer is running stably. If the liquid insulating medium level rises too quickly and reaches the position of the first oil level monitor 53, the quick vent valve 42 starts until the oil level reaches the position of the first oil level monitor 53.

[0066] Furthermore, in order to enable the first oil level monitor 53, the second oil level monitor 54, and the third oil level monitor 55 to...

[0067] The following combination Figure 8 The working process of the oil-immersed transformer of this application will be explained as follows:

[0068] First, the oil-immersed transformer is started. Then, the gas-filling component 40 starts to fill the gas. After that, the liquid level of the liquid insulating matrix reaches the position of the third oil level monitor 55, that is, the liquid level reaches the lower limit. Then, the gas-filling component 40 continues to fill the gas for 1 minute before stopping the filling.

[0069] Then, the working device 20 starts working. When the liquid level of the liquid insulating medium reaches the position of the second oil level monitor 54, the liquid level reaches the venting point, and the main venting valve 41 operates to vent the expansion member 30 for 2 minutes, after which venting stops. If the liquid level of the liquid insulating medium continues to reach the position of the second oil level monitor 54, the expansion member 30 is vented again for 2 minutes, and then venting stops.

[0070] When the liquid level of the liquid insulating medium reaches the position of the second oil level monitor 54, the liquid level reaches the upper limit. At this time, the air filling component 40 can be quickly vented through the quick vent valve 42 until the liquid level of the liquid insulating medium reaches the position of the third oil level monitor 55, that is, when the liquid level reaches the lower limit, the quick vent valve 42 stops venting.

[0071] The above-mentioned oil-immersed transformer has at least the following advantages:

[0072] By switching the expansion element 30 between its contracted and expanded states, the liquid level of the insulating medium can be adjusted. When the oil-immersed transformer starts up, the expansion element 30 can be switched to the expanded state to raise the liquid level, ensuring it is above the working device 20 and guaranteeing proper heat dissipation. After the transformer has been operating for a period of time, the liquid matrix expands due to heat. At this point, the expansion element 30 can be switched to the contracted state to lower the liquid level and prevent oil leakage.

[0073] Thus, the above-mentioned oil-immersed transformer controls the liquid level of the liquid insulating medium by switching between the expansion member 30 in a contracted state and an expanded state. This allows the oil-immersed transformer to be filled with less liquid insulating medium, thereby reducing its weight and preventing it from becoming overweight. This improves the adaptability of the oil-immersed transformer and reduces its manufacturing cost.

[0074] 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.

[0075] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An oil-immersed transformer, characterized in that, The oil-immersed transformer includes: The housing assembly (10) has an internal cavity (11) filled with a liquid insulating medium. The working device (20) is disposed within the receiving cavity (11); An expansion member (30) is disposed on the housing assembly (10) and / or the working device (20), and the expansion member (30) is located below the liquid surface of the liquid insulating medium. The expansion member (30) can be controlled to switch between an expanded state and a contracted state. During the process of switching from the contracted state to the expanded state, the volume of the expansion member (30) increases, and when the expansion member (30) switches from the expanded state to the contracted state, the volume of the expansion member (30) decreases.

2. The oil-immersed transformer according to claim 1, characterized in that, The expansion member (30) can be controlled to inflate or deflate, and when the expansion member (30) is inflated, the expansion member (30) switches from the contracted state to the inflated state, and when the expansion member (30) deflates, the expansion member (30) switches from the inflated state to the contracted state.

3. The oil-immersed transformer according to claim 2, characterized in that, The oil-immersed transformer also includes an air-filling component (40), which is disposed on the housing assembly (10). The housing assembly (10) is provided with a main exhaust valve (41) and an air-filling pipeline (43). The air-filling pipeline (43) connects the expansion component (30) and the air-filling component (40). The main exhaust valve (41) connects the expansion component (30) and the external atmosphere.

4. The oil-immersed transformer according to claim 3, characterized in that, The oil-immersed transformer also includes an oil conservator (50) and a control device (51). The oil conservator (50) is located on the top of the housing assembly (10), and an oil storage chamber (59) communicating with the working chamber is formed inside the oil conservator (50). An oil level sensor assembly (52) is provided inside the oil storage chamber (59). The oil level sensor assembly (52) is communicatively connected to the control device (51). The control device (51) is communicatively connected to the air filling component (40) and the main exhaust valve (41).

5. The oil-immersed transformer according to claim 4, characterized in that, The oil level sensor assembly (52) includes a first oil level monitor (53), a second oil level monitor (54) and a third oil level monitor (55) arranged sequentially along the direction of gravity. The first oil level monitor (53), the second oil level monitor (54) and the third oil level monitor (55) are all communicatively connected to the control device (51).

6. The oil-immersed transformer according to claim 2, characterized in that, A fixed hook (12) is also provided on the bottom wall of the receiving cavity (11), and a hanging part (31) is also provided on the expansion member (30), and the hanging part (31) is hung on the fixed hook (12).

7. The oil-immersed transformer according to claim 2, characterized in that, The oil-immersed transformer also includes a baffle (32), which is provided on the side of the expansion member (30) facing the liquid surface of the liquid insulating medium when the expansion member (30) is in the expanded state.

8. The oil-immersed transformer according to claim 7, characterized in that, A gas detector is provided on the baffle (32), which is used to detect the gas inside the expansion member (30) and issue an alarm signal.

9. The oil-immersed transformer according to claim 7, characterized in that, The oil-immersed transformer also includes an oil conservator (50), which has an oil storage chamber (59) and a breather valve that connects the oil storage chamber (59) to the outside atmosphere. The baffle (32) has an exhaust hole on the side facing the expansion member (30), and the housing assembly (10) has an exhaust passage that connects the exhaust hole and the oil storage chamber (59).

10. The oil-immersed transformer according to claim 7, characterized in that, The baffle (32) includes a first baffle (33) and a second baffle (34) arranged perpendicularly to each other. The first baffle (33) is connected to the expansion member (30), and when the expansion member (30) is in the expanded state, the second baffle (34) is in contact with the side wall of the receiving cavity (11), and the second baffle (34) is located on the side of the first baffle (33) away from the expansion member (30).

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