Oil tank magnetic shielding structure of transformer and high-capacity transformer

Abstract

The invention discloses an oil tank magnetic shielding structure of a transformer and a high-capacity transformer, the structure comprises a first tank wall and a second tank wall, and the first tank wall and the second tank wall surround the periphery of transformer body equipment. The first box wall comprises an installation part which extends in the vertical direction, the lower end edge of the installation part is lower than the upper end edge of the second box wall, and the upper end part of the second box wall is partially located on the outer side of the installation part. The magnetic shielding plate extends in the vertical direction, is mounted on the mounting part and is used for shielding a magnetic leakage magnetic field, the upper end edge of the magnetic shielding plate is higher than the upper end of the device body, and the lower end edge of the magnetic shielding plate is lower than the lower end of the device body, so that areas, corresponding to the magnetic leakage magnetic field, on the first box wall and the second box wall are magnetically shielded. The oil tank magnetic shielding structure of the transformer can absorb magnetic leakage generated by the transformer body, and then the eddy current loss of the transformer is reduced.

Description

Technical Field

[0001] This invention specifically relates to a magnetic shielding structure for a transformer tank and a large-capacity transformer incorporating the structure. Background Technology

[0002] Oil-immersed power transformers are a common type of power equipment. The outer shell (i.e., the oil tank) of an oil-immersed power transformer is filled with insulating oil, and the equipment inside the transformer is collectively referred to as the transformer body (including the iron core, windings, etc.), which is immersed in insulating oil.

[0003] Currently, large-capacity oil-immersed power transformers (e.g., 110-330kV) mostly use bell-type oil tanks. A bell-type oil tank consists of an upper tank and a lower tank, connected together. A cavity exists between the upper and lower tanks to house the transformer body. The advantage of this design is that during transformer body maintenance, it is unnecessary to remove the heavy transformer body; only the lighter tank shell portion needs to be lifted for repairs.

[0004] In oil-immersed power transformers, magnetic leakage occurs at the upper and lower main channels of the transformer body. This magnetic leakage, passing through the steel components such as the tank wall, generates eddy current losses, increases tank wall heating, and leads to increased transformer costs. The magnetic leakage phenomenon is particularly severe in large-capacity oil-immersed power transformers, and the existing bell-shaped oil tank walls cannot effectively shield against magnetic leakage. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the above-mentioned deficiencies in the prior art by providing a transformer tank magnetic shielding structure and a large-capacity transformer. The transformer tank magnetic shielding structure can absorb leakage magnetic flux generated in the transformer body, thereby reducing transformer eddy current losses.

[0006] According to an embodiment of a first aspect of the present invention, a magnetic shielding structure for a transformer tank is provided, comprising: a tank body and a magnetic shielding plate; the tank body has an internal accommodating cavity for accommodating the transformer core equipment, the transformer core equipment being surrounded by a leakage magnetic field, the tank body including a first tank wall and a second tank wall, the first tank wall and the second tank wall surrounding the transformer core equipment. The first tank wall is located above the second tank wall, the first tank wall and the second tank wall are detachably connected, and portions of the first tank wall and the second tank wall correspond to the leakage magnetic field. The first tank wall includes a mounting portion extending vertically, the lower edge of which is lower than the upper edge of the second tank wall, and the upper portion of the second tank wall is located outside the mounting portion. The magnetic shielding plate extends vertically and is mounted on the mounting portion for shielding the leakage magnetic field, the upper edge of the magnetic shielding plate being higher than the upper end of the transformer core equipment, and the lower edge being lower than the lower end of the transformer core equipment, to magnetically shield the areas on the first tank wall and the second tank wall corresponding to the leakage magnetic field.

[0007] Preferably, the mounting portion includes a first region and an extension. The first region is located at the lower end of the inner sidewall of the first housing wall, and the extension is located below the first region and connected to the first region. The extension extends downward, with its lower edge lower than the upper edge of the second housing wall. The upper half of the magnetic shielding plate is connected to the first region, and the lower half is connected to the extension.

[0008] Preferably, the second enclosure wall includes a second region located at the upper end of the inner sidewall of the second enclosure wall, and below the first region. The first region corresponds to the upper half of the device body, and its upper edge is higher than the upper end of the device body. The second region corresponds to the lower half of the device body, and its lower edge is lower than the lower end of the device body. The first and second regions are the areas to be shielded. The lower edge of the extension is lower than the second region, and the second region is located outside the extension. The upper edge of the magnetic shielding plate is higher than or aligned with the upper end of the first region, and its lower edge is lower than or aligned with the lower end of the second region, to cover the areas to be shielded.

[0009] Preferably, the magnetic shielding plate includes a first shielding plate and a second shielding plate. The upper halves of both the first and second shielding plates are connected to the first region, and the lower halves of both are connected to the extension. The upper edges of both the first and second shielding plates are higher than or aligned with the upper end of the first region, and the lower edges are lower than or aligned with the lower end of the second region. The first and second shielding plates are arranged opposite each other along a first horizontal direction. The device body is located between the first and second shielding plates. Leakage magnetic fields exist on both sides of the device body, and the first and second shielding plates are used to provide leakage magnetic shielding for the corresponding enclosure walls on both sides of the device body.

[0010] Preferably, the first region includes a first inner region and a second inner region, which are disposed opposite to each other along a first horizontal direction. The second region includes a third inner region and a fourth inner region, which are disposed opposite to each other along the first horizontal direction. The third inner region is located below the first inner region, and the fourth inner region is located below the second inner region. The extension includes a first extension and a second extension. The first extension is located below the first inner region and connected to it. The first extension extends downward, with its lower end below the third inner region, which is located outside the first extension. The second extension is located below the second inner region and connected to it. The second extension extends downward, with its lower end below the fourth inner region, which is located outside the second extension. The upper half of the first shielding plate is mounted on the first inner region, and the lower half is mounted on the first extension. The upper edge of the first shielding plate is higher than the first inner region, and the lower edge is lower than the third inner region. The upper half of the second shielding plate is installed in the second inner region, and the lower half is installed in the second extension. The upper edge of the second shielding plate is higher than the second inner region, and the lower edge is lower than the fourth inner region.

[0011] Preferably, the device body includes device body units, and the number of device body units is one or more, with the number of magnetic shielding plates corresponding to the number of device body units. Each device body unit corresponds to one magnetic shielding plate, and the first and second shielding plates of the magnetic shielding plate are respectively located on both sides of the device body unit.

[0012] Preferably, there are multiple body units, which are spaced apart along a second horizontal direction, which is perpendicular to the first horizontal direction; there are also multiple magnetic shielding plates, which are spaced apart along a second horizontal direction, and the distance L between the central axes of two adjacent magnetic shielding plates is equal to the center distance a of the body equipment.

[0013] Preferably, the widths of the first and second shielding plates of the magnetic shielding plate are equal, and the width of the first and second shielding plates is equal to the width of the area to be shielded. The heights of the first and second shielding plates of the magnetic shielding plate are equal, and the height of the first and second shielding plates is equal to the height of the area to be shielded. The width B of the first and second shielding plates is equal to a preset multiple of the outer diameter b of the device body unit, where the preset multiple is less than 1. The height H of the first and second shielding plates is greater than the height of the device body unit.

[0014] Preferably, the first shielding plate includes a plurality of first single plates, which extend vertically. The upper half of the first single plate is installed in the first inner region, and the lower half is installed in the first extension. The plurality of first single plates are arranged along the horizontal width direction of the first inner region. The second shielding plate includes a plurality of second single plates, which extend vertically. The upper half of the second single plate is installed in the second inner region, and the lower half is installed in the second extension. The plurality of second single plates are arranged along the horizontal width direction of the second inner region.

[0015] Preferably, the magnetic shielding structure of this fuel tank further includes clips, which include a first clip and a second clip. The first clip is used to fix a first single plate, and the second clip is used to fix a second single plate. Each first single plate has multiple first clips on both sides, and the multiple first clips located on one side of the first single plate are arranged at intervals along the extension direction of the first single plate. One end of the first clip is connected to the first inner region / first extension, and the other end is pressed against the surface of the first single plate. Each second single plate has multiple second clips on both sides, and the multiple second clips located on one side of the second single plate are arranged at intervals along the extension direction of the second single plate. One end of the second clip is connected to the second inner region / second extension, and the other end is pressed against the surface of the second single plate.

[0016] Preferably, the magnetic shielding structure of this fuel tank further includes a grounding plate. The number of grounding plates is multiple, and the number of grounding plates is the same as the sum of the number of the first single plate and the second single plate. Each grounding plate corresponds to one first single plate / second single plate. The grounding plate is located below the first single plate / second single plate, with one end connected to the lower end of the first single plate / second single plate and the other end connected to the first extension / second extension.

[0017] According to a second aspect of the present invention, a large-capacity transformer is provided, comprising: a transformer body and a transformer tank magnetic shielding structure; the transformer body is housed in the tank body of the transformer tank magnetic shielding structure, and the transformer tank magnetic shielding structure is used to shield the leakage magnetic field generated by the transformer body.

[0018] The magnetic shielding structure of the oil tank in this invention can absorb the leakage flux generated by the transformer body, thereby reducing the eddy current loss of the transformer. Specifically, leakage flux is prone to occur in the main channel of the transformer body unit. The leakage flux overflows from the main channel into the surrounding space, forming a leakage magnetic field. Among them, some leakage flux will pass through the oil tank wall, forming a closed loop and generating eddy current loss inside the oil tank wall.

[0019] This magnetic shielding structure for fuel tanks is particularly suitable for bell-shaped fuel tanks. The structure consists of a first region on the upper tank wall and a second region on the lower tank wall. These two regions combine to form the shielding area, which is the region with the highest density of leakage magnetic flux and requires focused shielding. It should be noted that because bell-shaped fuel tanks have a split upper and lower tank wall design, if the upper half of the magnetic shielding plate were installed in the first region of the upper tank and the lower half in the second region of the lower tank to fully cover the shielding area, it would make disassembly and reassembly between the upper and lower tank sections inconvenient. Therefore, to facilitate disassembly between the upper and lower tank sections, this magnetic shielding structure mounts the magnetic shielding plate on the upper tank section.

[0020] Furthermore, if only the magnetic shielding plate is installed in the first area, it may not adequately protect the lower part of the transformer body. A significant amount of leakage magnetic flux will still penetrate the lower tank wall, increasing heat generation in the steel components and raising transformer costs. To address this, the magnetic shielding structure of this tank features an extension at the lower end of the first area, extending downwards to completely cover the second area. Of course, the upper end of the second tank wall, at least the second area, must be located outside the extension to avoid it. This structural design allows magnetic shielding plates to be installed in both the first area and the extension, achieving leakage magnetic flux shielding for the entire shielded area.

[0021] In summary, this magnetic shielding structure for the fuel tank can achieve shielding of the main leakage magnetic flux area of ​​the entire side wall of the fuel tank without affecting the normal disassembly of the bell-shaped fuel tank. Attached Figure Description

[0022] Figure 1 This is a front structural schematic diagram of the oil tank magnetic shielding structure of a transformer in some embodiments of the present invention;

[0023] Figure 2 This is a partial side view of the oil tank magnetic shielding structure of a transformer in some embodiments of the present invention;

[0024] Figure 3 This is a schematic diagram showing the positional relationship between the oil tank magnetic shielding structure and the transformer body equipment in some embodiments of the present invention.

[0025] In the diagram: 1-tank body, 10-installation part, 11-first tank wall, 12-second tank wall, 13-first area, 14-second area, 15-extension, 16-upper tank edge, 17-lower tank edge, 2-magnetic shielding plate, 21-first single plate, 3-clamp, 4-grounding plate, 5-equipment, 6-leakage flux. Detailed Implementation

[0026] The technical solutions of the invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without creative effort are within the scope of the invention.

[0027] In the description of this invention, it should be noted that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience and simplification of 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.

[0028] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection," "setting," "installation," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0030] Example 1

[0031] Please see Figure 1 and Figure 2 The present invention discloses a magnetic shielding structure for a transformer tank, comprising: a tank body 1 and a magnetic shielding plate 2.

[0032] The tank body 1 has an internal cavity for housing the transformer core 5. A leakage magnetic field exists around the core 5. The tank body 1 includes a first tank wall 11 and a second tank wall 12, which surround the core 5. The first tank wall 11 is located above the second tank wall 12, and the two walls are detachably connected. The first and second tank walls partially correspond to the leakage magnetic field. The first tank wall 11 includes a mounting portion extending vertically, with its lower edge lower than the upper edge of the second tank wall 11. The upper part of the second tank wall 11 is located outside the mounting portion. A magnetic shielding plate 2 extends vertically and is mounted on the mounting portion to shield the leakage magnetic field. The upper edge of the magnetic shielding plate 2 is higher than the upper end of the core 5, and its lower edge is lower than the lower end of the core 5, thus providing magnetic shielding for the areas on the first and second tank walls corresponding to the leakage magnetic field.

[0033] Specifically, the cross-sections of the first box wall 11 and the second box wall 12 are adapted to each other, and the cross-sections of the two can be rectangular, rectangular with rounded corners, or circular, etc.

[0034] It should be noted that the main components of a transformer (component 5) include the core and windings. The core consists of core posts and a yoke. The core posts are the vertical parts of the core, and the windings are usually fitted onto them. In a three-phase transformer, there are typically three core posts, corresponding to the three-phase windings. The yoke is the horizontal part of the core, used to connect the core posts and form a closed magnetic circuit. Leakage flux mainly refers to the magnetic flux in transformers and other electromagnetic equipment that does not flow according to the magnetic circuit specified by the core, but instead overflows from the core and spreads into the surrounding space or other non-magnetic materials.

[0035] The winding is divided into a primary winding and a secondary winding. The primary winding is connected to the power supply and receives the input voltage; the secondary winding is connected to the load and outputs the transformed voltage. Both the primary and secondary windings are wound on the iron core. The primary and secondary windings are concentrically wound, with the secondary winding typically located outside the primary winding. The main winding is located between the secondary and primary windings. When an alternating current flows through the primary coil, an alternating magnetic flux is generated in the iron core, inducing a current in the secondary coil.

[0036] During transformer operation, the current in the winding coils generates magnetic flux around them. Because the transformer core has high permeability, most magnetic lines of force form closed magnetic loops through the core; this magnetic flux is called the main flux, which is the medium for electromagnetic coupling between the primary and secondary windings and is crucial for power transmission. However, not all the magnetic flux generated by the winding coil current passes through the core; some flux enters the transformer tank through weakly magnetic media such as transformer oil, forming another magnetic loop. This flux only links with the current in that winding and does not couple with other windings, offering no substantial help to the transformer's power transmission; therefore, it is called leakage flux.

[0037] In particular, leakage flux exists in the upper and lower main channels of the transformer body of large-capacity 110-330kV oil-immersed power transformers. This leakage flux will generate eddy current losses through the steel components such as the tank wall, increase the heating of the tank wall, and lead to an increase in the cost of the transformer.

[0038] Specifically, such as Figure 3 As shown, when the leakage flux 6 passes through the steel components such as the transformer tank wall, it induces a potential in these metal structures, thereby generating eddy currents. Eddy currents are currents induced inside a conductor by electromagnetic induction, flowing in a closed loop within the conductor. The presence of eddy currents generates resistive losses, i.e., eddy current losses, within the conductor. The magnitude of eddy current losses depends primarily on the conductor's dimensions, the magnitude and distribution of the leakage magnetic field. Eddy current losses are dissipated as heat, causing the temperature of the metal components such as the transformer tank wall to rise. This heating phenomenon not only increases the transformer's operating costs but may also adversely affect its insulation performance and service life. High-temperature environments accelerate the aging process of insulation materials, reducing their insulation performance and thus increasing the risk of transformer discharge and breakdown accidents.

[0039] To address this, the magnetic shielding structure of the oil tank in this invention can absorb the leakage flux generated by the transformer body, thereby reducing eddy current losses in the transformer. Specifically, leakage flux is prone to occur in the main channel of the transformer body unit, and the leakage flux 6 overflows from the main channel into the surrounding space, forming a leakage magnetic field. Among them, some of the leakage flux 6 will pass through the oil tank wall, forming a closed loop, and generating eddy current losses inside the oil tank wall.

[0040] This magnetic shielding structure for fuel tanks is particularly suitable for bell-shaped fuel tanks. In this embodiment, the lower edge of the mounting portion 10 extends downwards until it is below the second tank wall 11, with the upper portion of the second tank wall 11 located outside the mounting portion 10 to avoid the lower end of the mounting portion. Specifically, the upper edge of the mounting portion should be higher than or aligned with the region of the first tank wall 11 corresponding to the leakage magnetic field, and the lower edge of the mounting portion should be lower than or aligned with the region of the second tank wall 12 corresponding to the leakage magnetic field. Then, by installing a magnetic shielding plate on the mounting portion, the magnetic shielding plate should be able to cover the regions of the first tank wall 11 and the second tank wall 12 corresponding to the leakage magnetic field, thereby achieving leakage magnetic shielding for the first and second tank walls.

[0041] The advantage of this magnetic shielding structure for the fuel tank is that it can shield the main magnetic flux leakage area of ​​the entire side wall of the fuel tank without affecting the normal disassembly of the upper section of the bell-shaped fuel tank, and can effectively prevent magnetic leakage problems in the lower section of the fuel tank.

[0042] Specifically, the mounting section includes a first region 13 and an extension. The first region 13 is located at the lower end of the inner sidewall of the first housing wall 11. The extension is located below the first region and connected to the first region 13. The extension extends downward, and its lower edge is lower than the upper edge of the second housing wall. The upper half of the magnetic shielding plate 2 is connected to the first region 13, and the lower half is connected to the extension.

[0043] Further, the second enclosure wall 12 includes a second region 14, which is located at the upper end of the inner sidewall of the second enclosure wall 12 and is located below the first region 13. The first region 13 corresponds to the upper half of the device body, and the upper edge of the first region 13 is higher than the upper end of the device body. The second region 14 corresponds to the lower half of the device body, and the lower edge of the second region 14 is lower than the lower end of the device body. The first region 13 and the second region 14 are the areas to be shielded. The lower edge of the extension is lower than the second region 14, and the second region 14 is located outside the extension. The upper edge of the magnetic shielding plate 2 is higher than or aligned with the upper end of the first region 13, and the lower edge is lower than or aligned with the lower end of the second region 14 to cover the areas to be shielded.

[0044] In other words, this oil tank magnetic shielding structure uses a first region 13 on the upper tank wall and a second region 14 on the lower tank wall. The first region 13 and the second region 14 combine to form the shielding area, which is the region with the highest density of leakage magnetic flux 6 and requires focused shielding. It should be noted that because the bell-shaped oil tank has a split upper and lower tank wall design, if the upper half of the magnetic shielding plate 2 were installed in the first region 13 of the upper tank wall and the lower half in the second region 14 of the lower tank wall to fully cover the shielding area, it would make disassembly and installation between the upper and lower tank walls inconvenient. Therefore, to facilitate disassembly between the upper and lower tank walls, the magnetic shielding plate 2 is installed on the upper tank wall in this oil tank magnetic shielding structure.

[0045] In existing bell-shaped fuel tanks, the first tank wall 11 of the upper tank and the second tank wall 12 of the lower tank are on the same vertical plane. This ensures a fixed connection between the lower edge of the first tank wall 11 and the upper edge of the second tank wall 12. If the length of the magnetic shielding plate 2 is simply increased downwards, making its upper edge higher than the first region 13 and its lower edge lower than the second region 14, the magnetic shielding plate 2, due to its considerable weight, will become unstable. Furthermore, the magnetic shielding plate 2 is not suitable for installation via openings; therefore, it is typically installed using clips. This installation method relies primarily on the friction between the clips and the surface of the magnetic shielding plate 2 to secure it, which places requirements on the number of clips and the density of their connection points.

[0046] In other words, simply increasing the length of the magnetic shielding plate 2 downwards only allows for a fixed connection between the upper half of the magnetic shielding plate 2 and the first region 13. In this case, the clips can only be located on the upper half of the magnetic shielding plate 2, and the magnetic shielding plate 2 can only extend downwards by 10-30mm, meaning it can only be installed 10-30mm from the lower surface of the upper section's fuel tank wall. Extending downwards too much would significantly increase the weight of the magnetic shielding plate 2, making it impossible to secure it with the clips.

[0047] In addition, if the magnetic shielding plate 2 is installed only in the first area 13, it is easy to fail to protect the lower part of the transformer body well. That is, most of the leakage magnetic field will pass through the box wall of the lower section, increasing the heat of the steel parts and increasing the cost of the transformer.

[0048] In other words, oil-immersed transformers typically require magnetic shielding of the tank to absorb leakage flux. In conventional designs, the upper tank wall only extends into the upper tank edge 16, not beyond its lower surface. Due to height limitations of the upper tank, the magnetic shielding can only be installed 10-30mm from the lower surface of the upper tank wall. This results in the magnetic shielding failing to adequately protect the lower part of the transformer body. While the magnetic shielding can absorb some leakage flux from the lower part of the transformer body, the effect is poor. A significant portion of the leakage flux passes through the steel components, increasing heat generation in these components and leading to increased transformer costs.

[0049] To address this, the magnetic shielding structure of this fuel tank includes an extension 15 at the lower end of the first region 13, which extends downwards until it completely covers the second region 14. Of course, the upper end of the second tank wall 12, at least the second region 14, must be located outside the extension 15 to avoid it. With this structural design, magnetic shielding plates 2 can be installed on the first region 13 and the extension 15 to achieve leakage magnetic shielding for the entire shielded area.

[0050] In summary, this magnetic shielding structure for the fuel tank can achieve shielding of the main leakage magnetic flux area 6 of the entire sidewall of the fuel tank without affecting the normal disassembly of the bell-shaped fuel tank.

[0051] In this embodiment, since the leakage magnetic field of the device body exists around it, there will be areas on the tank walls on both sides of the device body that need to be shielded to shield the leakage magnetic field.

[0052] To address this, the magnetic shielding plate 2 includes a first shielding plate and a second shielding plate. The upper halves of both the first and second shielding plates are connected to the first region 13, and the lower halves are connected to the extension portion. The upper edges of both the first and second shielding plates are higher than or aligned with the upper end of the first region 13, and their lower edges are lower than or aligned with the lower end of the second region 14. The first and second shielding plates are arranged opposite each other along a first horizontal direction. The device 5 is located between the first and second shielding plates. Leakage magnetic fields exist on both sides of the device 5. The first and second shielding plates are used to provide leakage magnetic shielding for the corresponding enclosure walls on both sides of the device 5. The first horizontal direction corresponds to... Figure 2 The left and right directions in the middle correspond to Figure 1 The direction perpendicular to the paper.

[0053] Further, the first region 13 includes a first inner region and a second inner region, which are arranged opposite to each other along a first horizontal direction. The second region 14 includes a third inner region and a fourth inner region, which are arranged opposite to each other along a first horizontal direction, with the third inner region located below the first inner region and the fourth inner region located below the second inner region. Figure 2As shown, Figure 2 The image shows the first and third inner regions described above, located on the right side of the device body. Similarly, a second and fourth inner region are also provided on the left side of the device body. The first and third inner regions are the first areas to be shielded, and the second and fourth inner regions are the second areas to be shielded. Each area to be shielded is correspondingly equipped with a magnetic shielding plate 2. The first shielding plate is installed on the first area to be shielded, and the second shielding plate is installed on the second area to be shielded.

[0054] By setting the first shielding plate and the second shielding plate, the main leakage magnetic flux 6 on both sides of the device body can be effectively shielded to avoid eddy current loss on the tank wall.

[0055] Furthermore, the extension 15 includes a first extension and a second extension. The first extension is located below and connected to the first inner region, extending downwards with its lower end below the third inner region, which is located outside the first extension. The second extension is located below and connected to the second inner region, extending downwards with its lower end below the fourth inner region, which is located outside the second extension. The upper half of the first shielding plate is mounted on the first inner region, and the lower half is mounted on the first extension. The upper edge of the first shielding plate is higher than the first inner region, and the lower edge is lower than the third inner region. The upper half of the second shielding plate is mounted on the second inner region, and the lower half is mounted on the second extension. The upper edge of the second shielding plate is higher than the second inner region, and the lower edge is lower than the fourth inner region.

[0056] By connecting the first extension to the lower end of the first inner region and the second extension to the lower end of the second inner region, the shielding area of ​​the magnetic shielding plate 2 can be effectively increased, thereby effectively shielding and protecting the entire area to be shielded.

[0057] Please see Figure 1 In this embodiment, the device body 5 includes a device body unit, the number of which can be single or multiple, and the number of magnetic shielding plates 2 corresponds to the number of device body units; each device body unit corresponds to one magnetic shielding plate 2, and the first shielding plate and the second shielding plate of the magnetic shielding plate 2 are located on both sides of the device body unit.

[0058] A single transformer core unit consists of a core column and winding units. The number of core units depends on the number of phases of the transformer. For example, the core assembly 5 of a three-phase transformer contains three core units, while the core assembly 5 of a single-phase transformer contains one core unit. Furthermore, the leakage flux 6 of the transformer core mainly overflows from the main channel. Therefore, it is necessary to shield the leakage flux 6 overflowing from each main channel, and each core unit corresponds to one main channel. Thus, in this embodiment, as... Figure 1 As shown, by setting magnetic shielding plates 2 on both sides of each device unit, a better shielding effect on leakage flux 6 can be achieved.

[0059] Of course, in some other embodiments, the width of the magnetic shielding plate 2 can be increased to cover the leakage magnetic field of the three body units. However, this would greatly increase the weight of the shielding plate and the difficulty of installation, thereby significantly increasing the production cost.

[0060] In this embodiment, there are multiple body units, which are spaced apart along a second horizontal direction, perpendicular to the first horizontal direction. There are also multiple magnetic shielding plates 2, spaced apart along the second horizontal direction. The distance L between the central axes of two adjacent magnetic shielding plates 2 is equal to the center distance a of the body equipment 5. Specifically, the center distance a of the body equipment 5 refers to the distance between the central axes of the core columns of two adjacent body units. In other words, the central axis of each magnetic shielding plate 2 needs to correspond to the central axis of the body unit.

[0061] Taking a three-phase transformer as an example, there are three transformer body units and three magnetic shielding plates 2. The three magnetic shielding plates 2 are spaced apart along the second horizontal direction, such as... Figure 1 and Figure 2 As shown, the second horizontal direction is Figure 1 The left and right horizontal directions, and are Figure 2 The horizontal direction perpendicular to the plane of the paper. Taking a center distance 'a' of 1000mm for the transformer body 5 as an example, the center distance of each magnetic shielding plate 2 is also 1000mm. Of course, the spacing between the magnetic shielding plates 2 needs to be determined according to the parameters of the actual transformer being installed.

[0062] Furthermore, the widths of the first and second shielding plates of the magnetic shielding plate 2 are equal, and the widths of the first and second shielding plates are equal to the width of the area to be shielded. The heights of the first and second shielding plates of the magnetic shielding plate 2 are equal, and the heights of the first and second shielding plates are equal to the height of the area to be shielded. The width B of the magnetic shielding plate 2 is equal to the outer diameter b of the device body unit by a preset multiple, where the preset multiple is less than 1. The height H of the magnetic shielding plate 2 is greater than the height of the device body unit.

[0063] It should be noted that, as Figure 3 As shown, the first region 13, the second region 14, and the area to be shielded are concepts proposed for ease of description. In reality, the areas on the first box wall 11 and the second box wall 12 corresponding to the magnetic shielding plate 2 are the areas to be shielded, which are also the areas where the leakage magnetic flux 6 is relatively dense. By installing the magnetic shielding plate 2 in the areas where the leakage magnetic flux 6 is relatively dense, efficient shielding of the leakage magnetic flux 6 can be achieved. Therefore, it is necessary to optimize the size of the magnetic shielding plate 2 based on the distribution of the leakage magnetic flux 6.

[0064] In this embodiment, the aforementioned preset multiple is 0.6-0.7 times the outer diameter of the device body unit. Preferably, the preset multiple can be 0.6, 0.65, or 0.7 times. The height of the magnetic shielding plate 2 is the height of the device body unit plus mm.

[0065] For example, the dimensions of the magnetic shielding plate 2 are illustrated using 110kV, 220kV, and 330kV oil-immersed power transformers. The outer diameter of the transformer body unit of a 110kV transformer is 1500mm, and the height of the transformer body unit is 2500mm. The width B of the magnetic shielding plate 2 can be 900mm, 975mm, or 1050mm. The height of the magnetic shielding plate 2 can be 3000mm, 3050mm, or 3100mm.

[0066] The outer diameter of the transformer body unit of the 220kV transformer is 2000mm, and the height of the transformer body unit is 3500mm. The width B of the magnetic shielding plate 2 can be 1200mm, 1300mm, or 1400mm. The height of the magnetic shielding plate 2 can be 4000mm, 4050mm, or 4100mm.

[0067] The outer diameter of the transformer body unit of the 330kV transformer is 2500mm, and the height of the transformer body unit is 4000mm. The width B of the magnetic shielding plate 2 can be 1500mm, 1625mm, or 1750mm. The height of the magnetic shielding plate 2 can be 4500mm, 4550mm, or 4600mm.

[0068] Within this height and width range, the magnetic shielding plate 2 corresponds to the area where the leakage magnetic flux 6 is relatively dense, thus the magnetic shielding efficiency is relatively high.

[0069] Furthermore, the magnetic shielding plate 2 is preferably made of silicon steel sheets. Silicon steel is a material with high magnetic permeability. Using silicon steel sheets as the magnetic shielding plate 2 allows the magnetic permeability of these materials to be much higher than that of air or other non-magnetic materials. Therefore, they can more effectively guide the magnetic field lines, causing the magnetic field lines to flow mainly along the interior of the magnetic shielding plate 2 rather than diffuse outward, thereby reducing magnetic leakage.

[0070] As can be seen from the above description, even within the preferred size range, the size of the magnetic shielding plate 2 is still relatively large, which results in a significant weight. To reduce the weight and facilitate installation of the magnetic shielding plate 2, in this embodiment, each magnetic shielding plate 2 is composed of multiple individual plates. The distance between the outer edges of the individual plates at both ends is the width of the magnetic shielding plate 2.

[0071] Specifically, the first shielding plate includes multiple first single plates 21, which extend vertically. The upper half of each first single plate 21 is installed in a first inner region, and the lower half is installed in a first extension. The multiple first single plates 21 are arranged along the horizontal width direction of the first inner region. The second shielding plate includes multiple second single plates, which extend vertically. The upper half of each second single plate is installed in a second inner region, and the lower half is installed in a second extension. The multiple second single plates are arranged along the horizontal width direction of the second inner region.

[0072] In other words, a magnetic shielding mounting position is provided on the upper tank wall of the transformer, and a magnetic shielding plate 2 is installed on the magnetic shielding mounting position. The magnetic shielding plate 2 is composed of multiple single plates, which are narrow and long, and the multiple single plates are arranged along the width direction of the magnetic shielding mounting position.

[0073] The magnetic shielding plate 2, composed of multiple single pieces, has the following beneficial effects:

[0074] Firstly, by disassembling the magnetic shielding plate 2 into multiple individual plates, the overall weight of the magnetic shielding plate 2 can be distributed, making it easier to transport and install the magnetic shielding plate 2.

[0075] Secondly, because the single-plate is made of silicon steel, the leakage flux 6 will selectively pass through the high-permeability region. Therefore, the single-plate made of high-permeability material can more effectively attract and guide magnetic field lines, causing them to flow along the interior of the magnetic shielding plate 2, thereby reducing the occurrence of leakage flux 6. In other words, the leakage flux 6 generated by the device 5 will be attracted by the high-permeability magnetic shielding plate 2, and will not pass through the gap between two adjacent magnetic shielding plates 2. Therefore, the magnetic shielding plate 2 composed of multiple single plates can also maintain a good magnetic shielding effect.

[0076] Third, the narrow, elongated single-board design helps reduce the conductor cross-sectional area, thereby reducing eddy current losses. In an alternating magnetic field, eddy currents are generated in the conductor within the magnetic shielding plate 2. These eddy currents generate heat and consume energy. By reducing the conductor cross-sectional area, the magnitude and frequency of the eddy currents can be reduced, thereby reducing eddy current losses and improving the transformer's operating efficiency.

[0077] Please see Figure 1In this embodiment, the magnetic shielding structure of the fuel tank also includes clips 3, which are divided into first clips and second clips. The first clips are used to fix the first single plate 21, and the second clips are used to fix the second single plate. Each first single plate 21 has multiple first clips on both sides, and the multiple first clips on one side of the first single plate 21 are arranged at intervals along the extension direction of the first single plate 21. One end of the first clip is connected to the first inner region / first extension, and the other end is pressed against the surface of the first single plate 21. Each second single plate has multiple second clips on both sides, and the multiple second clips on one side of the second single plate are arranged at intervals along the extension direction of the second single plate. One end of the second clip is connected to the second inner region / second extension, and the other end is pressed against the surface of the second single plate.

[0078] Specifically, the clip 3 can be an iron sheet welded to the magnetic shielding installation position, with one end being a fixed welding end and the other end being a movable end. When installing the magnetic shielding plate 2, the worker bends the movable end so that the movable end presses against the surface of the magnetic shielding plate 2, thereby fixing the magnetic shielding plate 2.

[0079] In this embodiment, the magnetic shielding structure of the oil tank also includes grounding plates 4. There are multiple grounding plates 4, the number of which is the same as the sum of the numbers of the first single plate 21 and the second single plate. Each grounding plate 4 corresponds to one first single plate 21 / second single plate. The grounding plate 4 is located below the first single plate 21 / second single plate, with one end connected to the lower end of the first single plate 21 / second single plate and the other end connected to the first extension / second extension. By grounding the magnetic shielding plate 2 through the grounding plates, any leakage current or induced voltage that may occur can be introduced to the ground, thereby reducing the safety hazards to personnel and the equipment itself.

[0080] Please see Figure 1 and Figure 2 The magnetic shielding structure of the fuel tank in this embodiment is further explained as follows:

[0081] For high-capacity 110-330kV transformers, the upper section of the tank wall at the magnetic shielding is extended to the lower section of the tank. The length of the magnetic shielding is increased, and its lower part is installed 30-50mm from the extended lower section of the upper tank wall. In other words, the distance c between the lower edge of the magnetic shielding plate 2 and the lower edge of the extension is approximately 50mm to allow space for the installation of the grounding plate.

[0082] Furthermore, the lower fuel tank's edge is designed to be shorter than the upper fuel tank's edge, ensuring that the upper fuel tank's wall can extend deep into the lower fuel tank without interference. In other words, the lower fuel tank's edge is located outside the upper fuel tank's edge.

[0083] Compared with existing technologies, this oil tank magnetic shielding structure has the following advantages: extending the upper section of the oil tank wall at the magnetic shielding point to the lower section of the oil tank, the magnetic shielding can be extended to the lower section of the oil tank by lengthening the oil tank wall, thereby better protecting the lower part of the transformer body, absorbing the leakage magnetic flux generated at the lower part of the transformer body, and reducing the transformer eddy current loss.

[0084] The installation process of this oil tank magnetic shielding structure is as follows: 1. Weld the clips to the upper section of the oil tank wall (i.e., the first tank wall 11); 2. Weld the grounding plate to the upper section of the oil tank wall; 3. Weld the upper section of the oil tank wall to the upper section edge (i.e., the upper section edge 16); 4. Weld the lower section of the oil tank wall to the lower section edge (i.e., the lower section edge 17); 5. Install the magnetic shield (plate) onto the upper section of the oil tank wall, and bend the clips to press them onto the magnetic shield for fixation; 6. Finally, connect the upper and lower sections of the tank edge with bolts.

[0085] In summary, the magnetic shielding structure for the fuel tank in this embodiment has the following beneficial effects:

[0086] 1. This oil tank magnetic shielding structure can achieve shielding of the main leakage magnetic flux area 6 of the entire oil tank sidewall without affecting the normal disassembly between the upper and lower sections of the bell-shaped oil tank.

[0087] 2. The magnetic shielding structure of this fuel tank is composed of multiple individual pieces. Each individual piece is relatively light in weight and easy to disassemble and assemble. The magnetic shielding plate 2 formed by arranging multiple individual pieces along the width direction of the magnetic shielding installation position has a good shielding effect.

[0088] Example 2

[0089] The present invention also discloses a large-capacity transformer, including: the transformer body equipment 5 and the oil tank magnetic shielding structure of the transformer in embodiment 1.

[0090] The transformer body equipment 5 is housed in the tank body 1 of the oil tank magnetic shielding structure. The transformer oil tank magnetic shielding structure is used to shield the leakage magnetic field generated by the transformer body equipment 5.

[0091] The tank body 1 adopts a bell-shaped tank. By adopting the transformer tank magnetic shielding structure in Example 1, the shielding of the main leakage flux 6 area of ​​the entire tank sidewall can be achieved without affecting the normal disassembly between the upper and lower tank sections of the bell-shaped tank.

[0092] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A magnetic shielding structure for a transformer tank, characterized in that, include: Fuel tank body (1) and magnetic shielding plate (2); The tank body (1) has an internal cavity for accommodating the transformer body equipment (5). There is a leakage magnetic field around the transformer body equipment (5). The tank body (1) includes a first tank wall (11) and a second tank wall (12), which surround the transformer body equipment. The first box wall (11) is located above the second box wall (12), and the first box wall (11) and the second box wall (12) are detachably connected. The first box wall and the second box wall partially correspond to the leakage magnetic field. The first box wall (11) includes a mounting part (10), which extends vertically and has its lower edge lower than the upper edge of the second box wall (11). The upper part of the second box wall (11) is located outside the mounting part (10). The magnetic shielding plate (2) extends vertically and is installed on the mounting part (10) to shield the leakage magnetic field. The upper edge of the magnetic shielding plate (2) is higher than the upper end of the device body and the lower edge is lower than the lower end of the device body, so as to magnetically shield the areas on the first box wall and the second box wall corresponding to the leakage magnetic field.

2. The transformer tank magnetic shielding structure according to claim 1, characterized in that, The mounting portion includes a first region (13) and an extension. The first region (13) is located at the lower end of the inner sidewall of the first box wall (11). The extension is located below the first region and connected to the first region (13). The extension extends downward, and its lower edge is lower than the upper edge of the second box wall. The upper half of the magnetic shielding plate (2) is connected to the first region (13), and the lower half is connected to the extension.

3. The transformer tank magnetic shielding structure according to claim 2, characterized in that, The second box wall (12) includes a second region (14), which is located at the upper end of the inner sidewall of the second box wall (12) and is located below the first region (13). The first region (13) corresponds to the upper half of the device body, and the upper edge of the first region (13) is higher than the upper end of the device body. The second region (14) corresponds to the lower half of the device body, and the lower edge of the second region (14) is lower than the lower end of the device body. The first region (13) and the second region (14) are areas to be shielded. The lower edge of the extension is lower than the second region (14), and the second region (14) is located outside the extension; The upper edge of the magnetic shielding plate (2) is higher than or aligned with the upper end of the first region (13), and the lower edge is lower than or aligned with the lower end of the second region (14) to cover the area to be shielded.

4. The transformer tank magnetic shielding structure according to claim 3, characterized in that, The magnetic shielding plate (2) includes a first shielding plate and a second shielding plate. The upper half of the first shielding plate and the second shielding plate are both connected to the first region (13), and the lower half of the first shielding plate and the second shielding plate are both connected to the extension. The upper edges of the first shielding plate and the second shielding plate are both higher than or aligned with the upper end of the first region (13), and the lower edges are both lower than or aligned with the lower end of the second region (14). The first shielding plate and the second shielding plate are arranged opposite each other along the first horizontal direction. The device body (5) is located between the first shielding plate and the second shielding plate. There are leakage magnetic fields on both sides of the device body (5). The first shielding plate and the second shielding plate are used to shield the leakage magnetic fields of the corresponding box walls on both sides of the device body (5).

5. The transformer tank magnetic shielding structure according to claim 4, characterized in that, The first region (13) includes a first inner region and a second inner region, wherein the first inner region and the second inner region are arranged opposite to each other along a first horizontal direction; The second region (14) includes a third inner region and a fourth inner region, the third inner region and the fourth inner region being disposed opposite each other along a first horizontal direction, the third inner region being located below the first inner region, and the fourth inner region being located below the second inner region; The extension (15) includes a first extension and a second extension. The first extension is located below the first inner region and is connected to the first inner region. The first extension extends downward and its lower end is lower than the third inner region. The third inner region is located outside the first extension. The second extension is located below the second inner region and is connected to the second inner region. The second extension extends downward, and its lower end is lower than the fourth inner region. The fourth inner region is located outside the second extension. The upper half of the first shielding plate is installed in the first inner region, and the lower half is installed in the first extension. The upper edge of the first shielding plate is higher than the first inner region, and the lower edge is lower than the third inner region. The upper half of the second shielding plate is installed in the second inner region, and the lower half is installed in the second extension. The upper edge of the second shielding plate is higher than the second inner region, and the lower edge is lower than the fourth inner region.

6. The transformer tank magnetic shielding structure according to claim 4 or 5, characterized in that, The device body (5) includes device body units, the number of which can be single or multiple, and the number of magnetic shielding plates (2) corresponds to the number of device body units; Each of the device body units corresponds to a magnetic shielding plate (2), and the first shielding plate and the second shielding plate of the magnetic shielding plate (2) are located on both sides of the device body unit, respectively.

7. The transformer tank magnetic shielding structure according to claim 6, characterized in that, The number of the body units is multiple, and the multiple body units are spaced apart along a second horizontal direction, which is perpendicular to the first horizontal direction; The number of magnetic shielding plates (2) is also multiple, and the multiple magnetic shielding plates (2) are spaced apart along the second horizontal direction. The distance L between the central axes of two adjacent magnetic shielding plates (2) is equal to the center distance a of the device body (5).

8. The transformer tank magnetic shielding structure according to claim 7, characterized in that, The widths of the first shielding plate and the second shielding plate of the magnetic shielding plate (2) are equal, and the widths of the first shielding plate and the second shielding plate are equal to the width of the area to be shielded. The heights of the first shielding plate and the second shielding plate of the magnetic shielding plate (2) are equal, and the heights of the first shielding plate and the second shielding plate are equal to the height of the area to be shielded. The width B of the first shielding plate and the second shielding plate is equal to a preset multiple of the outer diameter b of the device body unit, where the preset multiple is less than 1, and the height H of the first shielding plate and the second shielding plate is greater than the height of the device body unit.

9. The transformer tank magnetic shielding structure according to claim 8, characterized in that, The first shielding plate includes a plurality of first single plates (21), the first single plates (21) extend in the vertical direction, the upper half of the first single plate (21) is installed in the first inner region, the lower half is installed in the first extension, and the plurality of first single plates (21) are arranged along the horizontal width direction of the first inner region. The second shielding plate includes a plurality of second single plates, which extend vertically. The upper half of the second single plate is installed in the second inner region, and the lower half is installed in the second extension. The plurality of second single plates are arranged along the horizontal width direction of the second inner region.

10. The transformer tank magnetic shielding structure according to claim 9, characterized in that, It also includes clips (3), which include a first clip and a second clip. The first clip is used to fix the first single board (21), and the second clip is used to fix the second single board. Each first single board (21) has multiple first clips on both sides, and the multiple first clips located on one side of the first single board (21) are arranged at intervals along the extension direction of the first single board (21). One end of the first clip is connected to the first inner area / first extension, and the other end is pressed against the surface of the first single board (21). Each second panel has multiple second clips on both sides, and the multiple second clips on one side of the second panel are arranged at intervals along the extension direction of the second panel. One end of the second clip is connected to the second inner area / second extension, and the other end is pressed against the surface of the second panel.

11. The transformer tank magnetic shielding structure according to claim 9 or 10, characterized in that, It also includes grounding plates (4), and there are multiple grounding plates (4). The number of grounding plates (4) is the same as the sum of the number of the first single plate (21) and the second single plate. Each grounding plate (4) corresponds to one first single plate (21) / second single plate. The grounding piece (4) is located below the first single plate (21) / second single plate, with one end connected to the lower end of the first single plate (21) / second single plate and the other end connected to the first extension / second extension.

12. A large-capacity transformer, characterized in that, include: The transformer body equipment (5) and the oil tank magnetic shielding structure of the transformer according to any one of claims 1-11; The transformer body equipment (5) is housed in the tank body (1) of the oil tank magnetic shielding structure, and the transformer oil tank magnetic shielding structure is used to shield the leakage magnetic field generated by the transformer body equipment (5).

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