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

Abstract

The utility model 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 a transformer body device. 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] The utility model particularly relates to a transformer oil tank magnetic shielding structure and a large-capacity transformer comprising the structure. Background Art

[0002] Oil-immersed power transformer is a common power equipment. The shell (i.e. oil tank) of the oil-immersed power transformer is filled with insulating oil. The equipment inside the transformer is collectively called the body (including iron core, winding, etc.), and the body is immersed in insulating oil.

[0003] Currently, large-capacity oil-immersed power transformers (e.g., 110-330kV) often use bell-shaped oil tanks. These consist of an upper and lower connected section, with a cavity between them for the transformer. This design allows for maintenance without having to remove the heavy transformer itself; only the lighter shell can be removed.

[0004] Oil-immersed power transformers experience magnetic flux leakage in the upper and lower main air paths within the transformer. This leakage passes through steel components such as the transformer walls, generating eddy current losses and increasing wall heating, leading to increased transformer costs. This leakage is particularly severe in large-capacity oil-immersed power transformers, and the existing bell-shaped oil tank walls are unable to effectively shield against this leakage. Utility Model Content

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

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

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

[0008] Preferably, the second box wall includes a second area, the second area is located at the upper end of the inner wall of the second box wall, and the second area is located below the first area. The first area corresponds to the upper half of the body equipment, and the upper edge of the first area is higher than the upper end of the body equipment. The second area corresponds to the lower half of the body equipment, and the lower edge of the second area is lower than the lower end of the body equipment. The first area and the second area are areas to be shielded. The lower edge of the extension is lower than the second area, and the second area is located on the outside of the extension. The upper edge of the magnetic shielding plate is higher than or aligned with the upper end of the first area, and the lower edge is lower than or aligned with the lower end of the second area, so as to cover the area to be shielded.

[0009] Preferably, the magnetic shielding plate includes a first shielding plate and a second shielding plate, the upper halves of the first shielding plate and the second shielding plate are both connected to the first region, and the lower halves of the first shielding plate and the second shielding plate are both connected to the extension portion. 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, and the lower edges are both lower than or aligned with the lower end of the second region, and the first shielding plate and the second shielding plate are arranged relative to each other along the first horizontal direction. The body device is located between the first shielding plate and the second shielding plate, and there is leakage magnetic field on both sides of the body device. The first shielding plate and the second shielding plate are used to perform leakage magnetic shielding on the corresponding box walls on both sides of the body device.

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

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

[0012] Preferably, there are multiple body units, and the multiple body units are arranged at intervals along the second horizontal direction, and the second horizontal direction is perpendicular to the first horizontal direction; there are also multiple magnetic shielding plates, and the multiple magnetic shielding plates are arranged at intervals along the second horizontal direction, and the spacing 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 first and second shielding plates of the magnetic shielding plate have equal widths, which are equal to the width of the area to be shielded. The first and second shielding plates of the magnetic shielding plate have equal heights, which are 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, each of which extends in a vertical direction, with an upper portion of the first single plate mounted in the first inner region and a lower portion mounted in the first extension portion, and the plurality of first single plates arranged along the horizontal width of the first inner region. The second shielding plate includes a plurality of second single plates, each of which extends in a vertical direction, with an upper portion of the second single plate mounted in the second inner region and a lower portion mounted in the second extension portion, and the plurality of second single plates arranged along the horizontal width of the second inner region.

[0015] Preferably, the magnetic shielding structure of the fuel tank also includes a clip, which includes a first clip and a second clip, the first clip is used to fix the first single plate, and the second clip is used to fix the second single plate, multiple first clips are arranged on both sides of each first single plate, 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 area / first extension portion, and the other end is pressed against the surface of the first single plate; multiple second clips are provided on both sides of each second single plate, 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 area / second extension portion, and the other end is pressed against the surface of the second single plate.

[0016] Preferably, the magnetic shielding structure of the oil tank also includes a grounding plate, and the number of the grounding plates is multiple, and the number of the grounding plates is the same as the sum of the number of the first single plate and the second single plate, and each grounding plate corresponds to a first single plate / second single plate; the grounding plate is located below the first single plate / second single plate, one end of which is connected to the lower end portion of the first single plate / second single plate, and the other end is connected to the first extension portion / second extension portion.

[0017] According to an embodiment of the second aspect of the present utility model, a large-capacity transformer is provided, comprising: a body device and the above-mentioned transformer oil tank magnetic shielding structure; the body device is accommodated in the oil tank body 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 body device.

[0018] The oil tank magnetic shielding structure of this utility model absorbs the leakage magnetic flux generated by the transformer body, thereby reducing the transformer's eddy current losses. Specifically, the main air channel within the transformer body unit is prone to magnetic leakage. This leakage flux overflows from the main air channel into the surrounding space, forming a leakage magnetic field. Some of this leakage flux passes through the oil tank wall, forming a closed loop and generating eddy current losses within the tank wall.

[0019] This oil tank magnetic shielding structure is particularly suitable for bell-shaped oil tanks. This oil tank magnetic shielding structure is achieved by setting a first area on the upper section tank wall and a second area on the lower section tank wall. The first area and the second area are combined to form an area to be shielded. The area to be shielded is an area where the leakage magnetic flux is relatively dense and needs to be shielded intensively. It should be noted that since the tank wall of the bell-shaped oil tank is designed to be split into upper and lower parts, if the upper half of the magnetic shielding plate is installed in the first area of ​​the upper section tank body and the lower half of the magnetic shielding plate is installed in the second area of ​​the lower section tank body in order to fully cover the area to be shielded, this will cause inconvenience in disassembly and installation between the upper section tank body and the lower section tank body. Therefore, in order to facilitate disassembly between the upper section tank body and the lower section tank body, this oil tank magnetic shielding structure installs the magnetic shielding plate on the upper section tank body.

[0020] Furthermore, if the magnetic shielding plate is installed only in the first area, it will easily lead to the inability to effectively protect the lower part of the device body, that is, most of the leakage magnetic flux will pass through the box wall of the lower section of the box body, increasing the heating of the steel parts and increasing the cost of the transformer. To this end, the magnetic shielding structure of the oil tank is provided with an extension portion at the lower end of the first area, and the extension portion extends downward until it completely covers the second area. Of course, at least the second area of ​​the upper end of the second box wall needs to be located outside the extension portion to avoid the extension portion. Through such a structural design, magnetic shielding plates can be installed on the first area and the extension portion to achieve leakage magnetic shielding of the entire shielded area.

[0021] In summary, the fuel tank magnetic shielding structure can shield the main leakage magnetic flux area of ​​the entire fuel tank side wall without affecting the normal disassembly of the bell-shaped fuel tank. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0024] Figure 3 It is a schematic diagram of 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 figure: 1-tank body, 10-mounting part, 11-first tank wall, 12-second tank wall, 13-first area, 14-second area, 15-extension part, 16-upper tank edge, 17-lower tank edge, 2-magnetic shielding plate, 21-first single board, 3-clip, 4-grounding plate, 5-device body equipment, 6-leakage magnetic flux. DETAILED DESCRIPTION

[0026] The following is a clear and complete description of the technical solutions of the utility model in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of the utility model.

[0027] In the description of the present invention, it should be noted that the terms "upper" and "lower" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience and simplification of the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as a limitation on the present invention.

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

[0029] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "connect," "dispose," "install," "fix," etc. should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integral connection; they may refer to direct connection, indirect connection through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0030] Example 1

[0031] See also Figure 1 and Figure 2 The utility model discloses a magnetic shielding structure of an oil tank of a transformer, comprising: an oil tank body 1 and a magnetic shielding plate 2.

[0032] The oil tank body 1 includes a chamber for accommodating the transformer body 5. A magnetic leakage field exists around the transformer body 5. The oil tank body 1 includes a first wall 11 and a second wall 12, which surround the transformer body. The first wall 11 is located above the second wall 12 and is detachably connected to the second wall 12. Portions of the first and second walls correspond to the magnetic leakage field. The first wall 11 includes a mounting portion that extends vertically, with its lower edge lower than the upper edge of the second wall 11. The upper end of the second 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 magnetic leakage field. The upper edge of the magnetic shielding plate 2 is higher than the upper end of the transformer body, and the lower edge is lower than the lower end of the transformer body, thereby magnetically shielding the areas of the first and second walls corresponding to the magnetic leakage 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, circular, etc.

[0034] It should be noted that the transformer body equipment 5 mainly includes an iron core and windings. The iron core includes an iron core column and an iron yoke. The iron core column is the vertical part of the iron core, and the winding is usually sleeved on the iron core column. In a three-phase transformer, there are usually three iron core columns, corresponding to the three-phase windings. The iron yoke is the horizontal part of the iron core, which is used to connect the iron core columns to form a closed magnetic circuit. Leakage flux mainly refers to the magnetic flux in electromagnetic equipment such as transformers that does not flow according to the magnetic circuit specified by the iron core, but overflows the iron core and spreads in the surrounding space or other non-magnetic materials.

[0035] The windings are divided into primary and secondary windings. 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 converted voltage. Both the primary and secondary windings are sheathed around the core leg. The primary and secondary windings are sheathed concentrically, with the secondary winding typically located outside the primary. The main air path is located between the secondary and primary windings. When AC current flows through the primary coil, AC magnetic flux is generated in the core, inducing a current in the secondary coil.

[0036] During transformer operation, the current flowing through the windings generates magnetic flux around them. Because the transformer's iron core has a high magnetic permeability, the magnetic lines of force mostly flow through it, forming a closed magnetic loop. This flux, known as the main flux, mediates electromagnetic coupling between the transformer's primary and secondary windings and is crucial for power transmission. However, not all of the magnetic flux generated by the winding current flows through the iron core. Some flux enters the transformer tank through weakly magnetically conductive media such as transformer oil, forming another magnetic flux loop. This flux only interlinks with the winding itself and does not couple with other windings. Therefore, it does not contribute substantially to the transformer's power transmission function. Therefore, it is called leakage flux.6 This generates magnetic flux leakage.

[0037] In particular, there will be leakage magnetic flux in the upper and lower main air channels inside the large-capacity 110-330kV oil-immersed power transformer. These leakage magnetic fluxes will generate eddy current losses when passing through steel parts such as the box wall, increase the heating of the box wall, and increase the cost of the transformer.

[0038] Specifically, if Figure 3 As shown, when the leakage magnetic flux 6 passes through steel parts such as the transformer box wall, it will induce an electric potential in these metal structural parts, thereby generating eddy currents. Eddy currents are currents induced inside the conductor by electromagnetic induction, and flow in a closed manner inside the conductor. Due to the existence of eddy currents, resistance losses, namely eddy current losses, will be generated inside the conductor. The magnitude of eddy current losses mainly depends on the size of the conductor, the size and distribution of the leakage magnetic field. Eddy current losses will be dissipated in the form of heat, causing the temperature of metal structural parts such as the transformer box wall to rise. This heating phenomenon will not only increase the operating cost of the transformer, but may also have an adverse effect on the insulation performance and service life of the transformer. Because the high temperature environment will accelerate the aging process of the insulating material and reduce its insulation performance, thereby increasing the risk of discharge and breakdown accidents in the transformer.

[0039] The oil tank magnetic shielding structure of the present invention absorbs the magnetic flux leakage generated by the transformer body, thereby reducing the transformer's eddy current losses. Specifically, the main air path within the transformer body unit is prone to magnetic flux leakage. Leakage flux 6 overflows from the main air path into the surrounding space, forming a leakage magnetic field. Some of this leakage flux 6 passes through the oil tank wall, forming a closed loop and generating eddy current losses within the tank wall.

[0040] This oil tank magnetic shielding structure is particularly suitable for bell-type oil tanks. In this embodiment, by extending the lower edge of the mounting portion 10 downward until it is lower than the second box wall 11, the upper end portion of the second box wall 11 is located on the outside of 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 area corresponding to the leakage magnetic field of the first box wall 11, and the lower edge of the mounting portion should be lower than or aligned with the area corresponding to the leakage magnetic field of the second box wall 12. Then, by installing a magnetic shielding plate on the mounting portion, the magnetic shielding plate should be able to cover the areas corresponding to the leakage magnetic field on the first box wall 11 and the second box wall 12, thereby achieving leakage magnetic shielding of the first box wall and the second box wall.

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

[0042] Specifically, 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, with its lower edge 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.

[0043] Furthermore, the second box wall 12 includes a second area 14, which is located at the upper end of the inner wall of the second box wall 12, and the second area 14 is located below the first area 13. The first area 13 corresponds to the upper half of the device body, and the upper edge of the first area 13 is higher than the upper end of the device body. The second area 14 corresponds to the lower half of the device body, and the lower edge of the second area 14 is lower than the lower end of the device body. The first area 13 and the second area 14 are areas to be shielded. The lower edge of the extension is lower than the second area 14, and the second area 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 area 13, and the lower edge is lower than or aligned with the lower end of the second area 14 to cover the area to be shielded.

[0044] In other words, the present oil tank magnetic shielding structure is formed by setting a first area 13 on the upper section tank wall and a second area 14 on the lower section tank wall. The first area 13 and the second area 14 are combined to form a to-be-shielded area. The to-be-shielded area is an area where the leakage magnetic flux 6 is relatively dense and needs to be shielded intensively. It should be noted that since the tank wall of the bell-shaped oil tank is designed to be split into upper and lower parts, if the upper half of the magnetic shielding plate 2 is installed in the first area 13 of the upper section tank body and the lower half of the magnetic shielding plate 2 is installed in the second area 14 of the lower section tank body in order to fully cover the to-be-shielded area, this will make the disassembly and installation between the upper section tank body and the lower section tank body inconvenient. Therefore, in order to facilitate the disassembly between the upper section tank body and the lower section tank body, the present oil tank magnetic shielding structure installs the magnetic shielding plate 2 on the upper section tank body.

[0045] In the existing bell-shaped oil tank, the first wall 11 of the upper oil tank and the second wall 12 of the lower oil tank are on the same vertical plane. In this way, the lower edge of the first wall 11 and the upper edge of the second wall 12 are fixedly connected. If the length of the magnetic shielding plate 2 is simply increased downward, so that the upper edge of the magnetic shielding plate 2 is higher than the first area 13 and the lower edge is lower than the second area 14; due to the large weight of the magnetic shielding plate 2 itself, the magnetic shielding plate 2 will be unstable. Furthermore, the magnetic shielding plate 2 itself is not suitable for installation through openings. Therefore, the magnetic shielding plate 2 is usually installed by clamping. This installation method mainly relies on the friction between the clamp and the surface of the magnetic shielding plate 2 to fix the magnetic shielding plate 2. There are requirements for the number of clamps and the distribution density of the connection points between the clamp and the magnetic shielding plate 2.

[0046] In other words, if the magnetic shielding plate 2 is simply extended downward, the upper portion of the plate 2 can only be fixed to the first region 13. In this case, the clips are located only in the upper portion of the plate 2, and the plate 2 can only extend downward 10 to 30 mm, meaning it can only be installed 10 to 30 mm from the lower surface of the upper fuel tank wall. If it extends downward too much, the plate 2 will be significantly heavier and unable to be secured by the clips.

[0047] In addition, if the magnetic shielding plate 2 is only installed 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 flux will pass through the box wall of the lower section of the box, increasing the heating of steel parts and increasing the cost of the transformer.

[0048] In other words, oil-immersed transformers typically require the cooperation of the oil tank magnetic shield to absorb leakage magnetic flux. Conventional designs of the upper oil tank wall only extend into the upper tank edge 16 and do not extend beyond the lower surface of the upper tank edge 16. Due to the height limitation of the upper oil tank, the magnetic shield can only be installed 10 to 30 mm from the lower surface of the upper oil tank wall. This results in the magnetic shield failing to effectively protect the lower part of the transformer. As a result, the oil tank magnetic shield can absorb some leakage magnetic flux from the lower part of the transformer, but the effect is not good. Most of the leakage magnetic flux will pass through the steel parts and cause magnetic flux leakage, increasing the heat of the steel parts and leading to increased transformer costs.

[0049] To address this issue, the present fuel tank magnetic shielding structure features an extension 15 at the lower end of the first region 13. This extension 15 extends downward 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. This structural design allows the magnetic shielding plate 2 to be installed over the first region 13 and the extension 15, effectively shielding the entire shielded area from magnetic flux leakage.

[0050] In summary, the magnetic shielding structure of the fuel tank can shield the main leakage magnetic flux 6 area of ​​the entire fuel tank side wall 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 are shielding areas on the oil tank walls on both sides of the device body that need to shield the leakage magnetic field.

[0052] In this regard, the magnetic shielding plate 2 includes a first shielding plate and a second shielding plate. The upper halves of the first shielding plate and the second shielding plate are connected to the first region 13, and the lower halves of the first shielding plate and the second shielding plate are connected to the extension portion. The upper edges of the first shielding plate and the second shielding plate are higher than or aligned with the upper end of the first region 13, and the lower edges are lower than or aligned with the lower end of the second region 14. The first shielding plate and the second shielding plate are arranged relative to each other along the first horizontal direction. The body device 5 is located between the first shielding plate and the second shielding plate. There is leakage magnetic field on both sides of the body device 5. The first shielding plate and the second shielding plate are used to perform leakage magnetic shielding on the box walls corresponding to both sides of the body device 5. Among them, the first horizontal direction corresponds to Figure 2 The left and right directions in Figure 1 The direction perpendicular to the paper.

[0053] Furthermore, the first area 13 includes a first inner area and a second inner area, and the first inner area and the second inner area are arranged opposite to each other along the first horizontal direction. The second area 14 includes a third inner area and a fourth inner area, and the third inner area and the fourth inner area are arranged opposite to each other along the first horizontal direction. The third inner area is located below the first inner area, and the fourth inner area is located below the second inner area. Figure 2As shown, Figure 2 The first and third inner regions are shown in the figure. They are located on the right side of the device body. Similarly, the second and fourth inner regions are located on the left side of the device body. The first and third inner regions are the first shielded area, while the second and fourth inner regions are the second shielded area. Each shielded area is correspondingly mounted with a magnetic shielding plate 2. The first shielding plate is mounted on the first shielding area, and the second shielding plate is mounted on the second shielding area.

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

[0055] Furthermore, the extension portion 15 includes a first extension portion and a second extension portion. The first extension portion is located below and connected to the first inner region. The first extension portion extends downward, with its lower end lower than the third inner region, which is located outside the first extension portion. The second extension portion is located below and connected to the second inner region. The second extension portion extends downward, with its lower end lower than the fourth inner region, which is located outside the second extension portion. 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 portion. 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 portion. 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 portion to the lower end of the first inner region and the second extension portion 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 the entire shielding area.

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

[0058] A single body unit is composed of an iron core column and a winding unit. The number of body units is determined by the number of phases of the transformer. For example, the body device 5 of a three-phase transformer includes three body units, and the body device 5 of a single-phase transformer includes one body unit. Furthermore, the leakage flux 6 of the transformer body mainly overflows from the main air channel. Therefore, it is necessary to shield the leakage flux 6 overflowing from each main air channel separately, and each body unit corresponds to a main air channel. Therefore, in this embodiment, if Figure 1 As shown, magnetic shielding plates 2 are respectively provided on both sides of each body unit to achieve a better shielding effect on the leakage magnetic flux 6 .

[0059] Of course, in other embodiments, the width of the magnetic shielding plate 2 can be increased so that the width of the magnetic shielding plate 2 can cover the leakage magnetic field of three body units. However, this will 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, 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 spacing L between the center axes of two adjacent magnetic shielding plates 2 is equal to the center-to-center distance a of the body device 5. Specifically, the center-to-center distance a of the body device 5 refers to the spacing between the center axes of the core legs of two adjacent body units. In other words, the center axis of each magnetic shielding plate 2 must correspond to the center axis of the body unit.

[0061] Taking a three-phase transformer as an example, the number of the body units is three, and the number of the magnetic shielding plates 2 is also three. 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 in Figure 2 The horizontal direction perpendicular to the paper. Taking the center distance a of the device body 5 as 1000 mm as an example, the center distance of each magnetic shielding plate 2 is also 1000 mm. Of course, the spacing between the magnetic shielding plates 2 needs to be determined according to the parameters of the actual installed transformer.

[0062] Furthermore, 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 magnetic shielding plate 2 is equal to the outer diameter b of the device body unit multiplied by a preset multiple, and the preset multiple is less than 1; and 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 if Figure 3 As shown, the first area 13, second area 14, and area to be shielded are concepts introduced for ease of description. In practice, the area on the first and second walls 11, 12 corresponding to the magnetic shielding plate 2 is the area to be shielded, i.e., the area with a high concentration of leakage flux 6. By installing the magnetic shielding plate 2 in this area with a high concentration of leakage flux 6, efficient shielding of leakage flux 6 can be achieved. Therefore, the size of the magnetic shielding plate 2 should be optimized based on the distribution of leakage flux 6.

[0064] In this embodiment, the preset multiple is 0.6-0.7 times the outer diameter of the 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 body unit + mm.

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

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

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

[0068] The magnetic shielding plate 2 within this height and width range corresponds to an area where the leakage magnetic flux 6 is relatively dense, and 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 can help these materials achieve a much higher magnetic permeability than air or other non-magnetic materials. Therefore, they can more effectively guide magnetic field lines, causing them to flow primarily along the interior of the magnetic shielding plate 2 rather than spreading outward, thereby reducing magnetic flux leakage.

[0070] As can be seen from the above description, within the preferred size range, the magnetic shielding panels 2 are still relatively large, resulting in significant weight. To reduce the weight of the magnetic shielding panels 2 and facilitate installation, in this embodiment, each magnetic shielding panel 2 is composed of multiple single panels. The distance between the outer edges of the single panels at both ends is the width of the magnetic shielding panel 2.

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

[0072] In other words, a magnetic shielding mounting position is provided on the upper oil 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, each of which is 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] First, by decomposing the magnetic shielding panel 2 into a plurality of individual panels, the weight of the entire magnetic shielding panel 2 can be dispersed, thereby facilitating the transportation and installation of the magnetic shielding panel 2 .

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

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

[0077] See also Figure 1In this embodiment, the fuel tank magnetic shielding structure further includes a clip 3, which is divided into a first clip and a second clip. The first clip is used to secure the first single plate 21, and the second clip is used to secure the second single plate. Multiple first clips are provided on both sides of each first single plate 21, and the multiple first clips located on one side of the first single plate 21 are spaced apart 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 portion, and the other end is pressed against the surface of the first single plate 21. Multiple second clips are provided on both sides of each second single plate, and the multiple second clips located on one side of the second single plate are spaced apart along the extension direction of the second single plate. One end of the second clip is connected to the second inner region / second extension portion, 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, one end of which is a welded fixed end and the other end is a movable end. When installing the magnetic shielding plate 2, the staff bends the movable end so that the movable end is pressed tightly against the surface of the magnetic shielding plate 2, thereby fixing the magnetic shielding plate 2.

[0079] In this embodiment, the fuel tank magnetic shielding structure further includes a grounding plate 4. There are multiple grounding plates 4, which are equal in number to the sum of the first and second plates 21. Each grounding plate 4 corresponds to a first plate 21 or second plate. The grounding plate 4 is located below the first plate 21 or second plate, with one end connected to the lower end of the first plate 21 or second plate and the other end connected to the first extension or second extension. Grounding the magnetic shielding plate 2 via the grounding plate 4 directs any potential leakage current, induced voltage, and other potential hazards to personnel and the equipment itself.

[0080] See also Figure 1 and Figure 2 , the magnetic shielding structure of the fuel tank in this embodiment is further described:

[0081] For large-capacity, 110-330kV transformers, the design extends the upper section of the oil tank's magnetic shield to the lower section. This increases the length of the oil tank's magnetic shield, with the lower portion installed 30-50mm from the extended lower section of the upper tank. In other words, the distance c between the lower edge of the magnetic shield plate 2 and the lower edge of the extended portion is approximately 50mm, leaving room for the grounding lug.

[0082] Furthermore, the lower fuel tank edge is shorter than the upper fuel tank edge during design, ensuring that the upper fuel tank wall can penetrate the lower fuel tank without interference. In other words, the tank edge of the lower fuel tank is located outside the upper fuel tank edge.

[0083] Compared with the existing technology, the oil tank magnetic shielding structure has the following beneficial effects: the upper section of the oil tank wall at the oil tank magnetic shielding is extended to the lower section of the oil tank. By lengthening the oil tank wall, the oil tank magnetic shielding can be extended to the lower section of the oil tank, thereby better protecting the lower body of the transformer, absorbing the leakage magnetic generated at the lower body, and reducing the eddy current loss of the transformer.

[0084] The installation process for this fuel tank magnetic shielding structure is as follows: 1. Weld the clips to the upper fuel tank wall (i.e., first tank wall 11); 2. Weld the grounding plate to the upper fuel tank wall. 3. Weld the upper fuel tank wall to the upper tank rim (i.e., upper tank rim 16); 4. Weld the lower fuel tank wall to the lower tank rim (i.e., lower tank rim 17). 5. Install the magnetic shield (plate) to the upper fuel tank wall and bend the clips to press onto the magnetic shield to secure it. 6. Finally, bolt the upper and lower tank rims together.

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

[0086] 1. The magnetic shielding structure of the fuel tank can shield the main leakage magnetic flux 6 areas of the entire fuel tank side wall without affecting the normal disassembly between the upper and lower sections of the bell-shaped fuel tank.

[0087] 2. The magnetic shielding structure of the fuel tank is composed of multiple single pieces, each of which is relatively light and easy to assemble and disassemble. In addition, the magnetic shielding plate 2 formed by arranging multiple single pieces along the width direction of the magnetic shielding installation position has a good shielding effect.

[0088] Example 2

[0089] The utility model also discloses a large-capacity transformer, comprising: a transformer body device 5 and the oil tank magnetic shielding structure of the transformer in embodiment 1.

[0090] The transformer body device 5 is accommodated in the oil 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 device 5 .

[0091] The oil tank body 1 adopts a bell-type oil tank. By adopting the oil tank magnetic shielding structure of the transformer in Example 1, it is possible to achieve shielding of the main leakage magnetic flux 6 area of ​​the entire oil tank side wall without affecting the normal disassembly between the upper and lower sections of the bell-type oil tank.

[0092] It is understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present invention, and the present invention is not limited thereto. Those skilled in the art may make various modifications and improvements without departing from the spirit and substance of the present invention, and such modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A magnetic shielding structure for an oil tank of a transformer, characterized in that: include: A fuel tank body (1) and a magnetic shielding plate (2); The oil tank body (1) is provided with a receiving cavity inside, the receiving cavity is used to receive a transformer body device (5), a leakage magnetic field exists around the transformer body device (5), and the oil tank body (1) comprises a first box wall (11) and a second box wall (12), the first box wall (11) and the second box wall (12) surrounding the transformer body device; The first box wall (11) is located above the second box wall (12), the first box wall (11) and the second box wall (12) are detachably connected, and the first box wall and the second box wall partially correspond to the leakage magnetic field; The first box wall (11) includes a mounting portion (10), the mounting portion (10) extends in a vertical direction, the lower edge of the mounting portion is lower than the upper edge of the second box wall (12), and the upper end portion of the second box wall (12) is located outside the mounting portion (10); The magnetic shielding plate (2) extends in a vertical direction and is mounted on the mounting portion (10) for shielding leakage magnetic fields. 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 fields.

2. The transformer oil tank magnetic shielding structure according to claim 1, characterized in that: The mounting portion includes a first area (13) and an extension portion, wherein the first area (13) is located at the lower end of the inner side wall of the first box wall (11), the extension portion is located below the first area and connected to the first area (13), and the extension portion extends downward, with a lower end edge lower than an upper end 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 portion.

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

4. The transformer oil tank magnetic shielding structure according to claim 3, characterized in that: The magnetic shielding plate (2) comprises a first shielding plate and a second shielding plate, wherein the upper halves of the first shielding plate and the second shielding plate are both connected to the first region (13), and the lower halves of the first shielding plate and the second shielding plate are both connected to the extension portion; 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), and the first shielding plate and the second shielding plate are arranged relative to each other along a first horizontal direction; The device body (5) is located between the first shielding plate and the second shielding plate, and leakage magnetic fields exist on both sides of the device body (5). The first shielding plate and the second shielding plate are used to perform leakage magnetic shielding on the box walls corresponding to the two sides of the device body (5).

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

6. The transformer oil tank magnetic shielding structure according to claim 5, characterized in that: The body device (5) comprises a body unit, the number of the body units is single or multiple, and the number of the magnetic shielding plates (2) corresponds to the number of the body units; Each of the body units corresponds to a magnetic shielding plate (2), and a first shielding plate and a second shielding plate of the magnetic shielding plate (2) are respectively located on two sides of the body unit.

7. The transformer oil tank magnetic shielding structure according to claim 6, characterized in that: There are multiple body units, and the multiple body units are spaced apart along a second horizontal direction, and the second horizontal direction is perpendicular to the first horizontal direction; The number of the magnetic shielding plates (2) is also multiple, and the multiple magnetic shielding plates (2) are spaced apart along the second horizontal direction, and the spacing 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 oil tank magnetic shielding structure according to claim 7, characterized in that: The first shielding plate and the second shielding plate of the magnetic shielding plate (2) have equal widths, 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 first shielding plate and the second shielding plate of the magnetic shielding plate (2) have equal heights, 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 body unit, and the preset multiple is less than 1. The height H of the first shielding plate and the second shielding plate is greater than the height of the body unit.

9. The transformer oil tank magnetic shielding structure according to claim 8, characterized in that: The first shielding plate comprises a plurality of first single plates (21), the first single plates (21) extending in a vertical direction, an upper half of the first single plate (21) being mounted on the first inner region, and a lower half being mounted on the first extension portion, and the plurality of first single plates (21) being arranged in a horizontal width direction of the first inner region; The second shielding plate includes multiple second single plates, which extend in the vertical direction. The upper half of the second single plate is installed in the second inner area, and the lower half is installed in the second extension part. The multiple second single plates are arranged along the horizontal width direction of the second inner area.

10. The transformer oil tank magnetic shielding structure according to claim 9, characterized in that: It also includes a clip (3), the clip (3) including 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. A plurality of first clips are provided on both sides of each first single board (21), and the plurality of 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 portion, and the other end is pressed against the surface of the first single board (21); Multiple second clips are provided on both sides of each second single board, and the multiple second clips located on one side of the second single board are arranged at intervals along the extension direction of the second single board, one end of the second clip is connected to the second inner area / second extension part, and the other end is pressed against the surface of the second single board.

11. The transformer oil tank magnetic shielding structure according to claim 9 or 10, characterized in that: It also includes a grounding plate (4), wherein the number of the grounding plates (4) is multiple, the number of the grounding plates (4) is the same as the sum of the number of the first single board (21) and the second single board, and each grounding plate (4) corresponds to one first single board (21) / second single board; The grounding plate (4) is located below the first single board (21) / the second single board, one end of which is connected to the lower end of the first single board (21) / the second single board, and the other end of which is connected to the first extension part / the second extension part.

12. A large capacity transformer, characterized in that: include: The transformer body device (5) and the oil tank magnetic shielding structure according to any one of claims 1 to 11; The transformer body equipment (5) is accommodated in the oil 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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