A magnetic shielding assembly

Abstract

The application discloses a magnetic shielding assembly, and relates to the technical field of power transmission equipment, which comprises a shielding main body layer, an electrode layer and an insulation layer. The shielding main body layer is formed by stacking a plurality of shielding sheets in the height direction of the shielding main body layer, and the inner side surface of the shielding main body layer is provided with a concave arc surface which faces a coil. The electrode layer is laid on the inner side surface of the shielding main body layer, and the surface of the electrode layer which faces away from the shielding main body layer is a smooth surface. The insulation layer is laid between the shielding main body layer and the electrode layer, and is used for isolating the shielding main body layer from the electrode layer. The magnetic shielding assembly can further reduce the transformer loss and reduce the volume of the transformer, and realizes the optimization of technology and economy.

Description

Technical Field

[0001] This application relates to the field of power transmission equipment technology, and in particular to a magnetic shielding component and a transformer. Background Technology

[0002] With the construction of new power systems and the development of high-voltage, large-capacity flexible AC / DC transmission technology, transformer equipment is increasingly trending towards larger capacity, higher voltage, and larger size. In particular, flexible low-frequency transmission has gradually become a hot topic in engineering technology in recent years due to its low-loss and other technical and economic advantages. The core and dimensions of low-frequency transformers of the same voltage level and capacity are significantly larger than those of power-frequency transformers, and leakage flux is also increased. Therefore, with the application of high-voltage, large-capacity transformers and low-frequency transformers, how to achieve low loss, low temperature rise, and long-term safe and reliable operation of transformers while meeting the requirements for transformer transportation dimensions is the most pressing technical issue for the transformer industry.

[0003] The largest stray loss in a transformer originates from the leakage magnetic field generated by the current in the transformer coils and leads, i.e., leakage magnetic loss. Therefore, magnetic or electrical shielding is commonly used on the transformer tank to suppress leakage magnetic loss. However, existing methods for suppressing leakage magnetic loss still have some shortcomings:

[0004] For example, Chinese patent CN211654522U discloses a transformer tank structure that meets railway transportation requirements, with magnetic shielding consisting of copper shielding and insulating paper. This method is affected by the rising price of copper due to increasing resource scarcity and the high demand for shielding materials in large transformers, leading to increasingly higher transformer manufacturing costs. Furthermore, the insulating paper is not durable and is prone to aging.

[0005] For example, Chinese patent CN2831360Y discloses an active field magnetically shielded oil-immersed transformer. Its magnetic shielding method involves stacking several very thin silicon steel sheets along their thickness direction to form the width of the magnetic shielding wall. This method fails to consider that unevenness can occur during the stacking process of the silicon steel sheets. When a single silicon steel sheet protrudes, it can easily lead to abnormal discharge phenomena (especially in high-voltage transformers).

[0006] As can be seen from the above, the effectiveness of reducing transformer losses still needs further improvement, and simply reducing losses is no longer sufficient to achieve technical and economic optimization. How to further reduce transformer losses while simultaneously reducing transformer size and ensuring safe and reliable operation of the equipment to achieve technical and economic optimization has become an urgent problem to be solved. Summary of the Invention

[0007] In view of this, the purpose of this application is to provide a magnetic shielding component that can further reduce transformer losses while reducing transformer size, thereby achieving technical and economic optimization.

[0008] To achieve the above technical objectives, this application provides a magnetic shielding assembly, including a shielding body layer, an electrode layer, and an insulating layer;

[0009] The shielding main layer is formed by stacking multiple shielding sheets in its height direction. The inner side of the shielding main layer has a concave arc-shaped surface, which faces the coil.

[0010] The electrode layer is laid on the inner side of the shielding main body layer, and the side of the electrode layer facing away from the shielding main body layer is a smooth surface.

[0011] The insulating layer is laid between the shielding body layer and the electrode layer to isolate the shielding body layer from the electrode layer.

[0012] Furthermore, the shielding sheet is a silicon steel sheet.

[0013] Furthermore, the electrode layer is a conductor layer or a semiconductor layer.

[0014] Furthermore, the area of ​​the electrode layer is smaller than the area of ​​the inner side surface of the shielding body layer.

[0015] Furthermore, the electrode layer is formed by assembling multiple sub-electrode layers.

[0016] Furthermore, the insulating layer is an insulating varnish layer.

[0017] As can be seen from the above technical solutions, the magnetic shielding assembly designed in this application has a shielding main layer formed by stacking multiple shielding sheets along its height. The sum of the thickness of each shielding sheet is the height of the shielding main layer, which can more effectively absorb magnetic leakage caused by current in the coil and leads. Furthermore, a concave arc-shaped surface facing the coil is provided on the inner side of the shielding main layer, allowing for better adaptation to the coil shape while maintaining the required insulation distance between the shielding main layer and the coil. The shielding assembly with this design occupies a smaller volume than the traditional rectangular structure design when used with the coil. This allows the transformer housing to be manufactured into a suitable shape, resulting in a smaller volume. The arc-shaped structure also provides better structural strength to the transformer housing. Moreover, by laying an electrode layer on the inner side of the shielding main layer, and ensuring that the side of the electrode layer facing away from the shielding main layer is smooth, the inner side of the stacked shielding main layer becomes flat, overcoming the unevenness of the electric field and preventing abnormal discharge. Simultaneously, an insulating layer is provided between the electrode layer and the shielding body layer to prevent the electrode layer from rusting and affecting the shielding body layer, or vice versa. This also prevents intermittent breakdown discharge to ground in the electrode layer, thereby reducing eddy current losses. The magnetic shielding assembly designed above can further reduce transformer losses while minimizing transformer size, achieving technical and economic optimization. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a structural diagram of the shielding main layer of a magnetic shielding assembly provided in this application;

[0020] Figure 2 This is a structural diagram of a single shielding sheet of a magnetic shielding assembly provided in this application;

[0021] Figure 3 This is a schematic diagram of the mating structure between the shielding body layer and the coil of a magnetic shielding assembly provided in this application;

[0022] Figure 4 This is a partial cross-sectional view of a magnetic shielding assembly provided in this application applied to a transformer housing;

[0023] In the diagram: 1. Shielding main layer; 10. Concave arc surface; 11. Shielding sheet; 2. Electrode layer; 3. Insulation layer; 100. Transformer housing; 201. Coil. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the embodiments of this application.

[0025] In the description of the embodiments of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0026] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a replaceable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0027] This application discloses a magnetic shielding component.

[0028] Please see Figures 1 to 4 One embodiment of a magnetic shielding component provided in this application includes:

[0029] The shielding layer 1, the electrode layer 2, and the insulating layer 3.

[0030] The shielding main body layer 1 consists of multiple components in its height direction, such as... Figure 2The shielding sheets 11 shown are stacked to form a shielding body layer 1. This stacking design, which is the thickness of each shielding sheet 11 after stacking and the height of the shielding body layer 1, can also be understood as stacking the shielding sheets 11 perpendicular to the wall of the transformer box 100 in the vertical direction to obtain the shielding body layer 1 of this design. Through such a stacking design, the magnetic leakage generated by the current in the coil 201 and the lead wire in the transformer can be absorbed more effectively.

[0031] The inner surface of the shielding main body layer 1 has a concave arc-shaped surface 10, which is a cylindrical arc surface facing the coil 201. This design allows the shielding main body layer 1 to better fit the shape of the coil 201 while maintaining the insulation safety distance between the shielding main body layer 1 and the coil 201. When the shielding assembly with this design is used with the coil 201, the volume it occupies is smaller than that of the traditional rectangular structure design. This allows the transformer housing 100 to be manufactured into a suitable shape, resulting in a smaller volume. Simultaneously, the arc-shaped structure design also provides the transformer housing 100 with better structural strength. In summary, this magnetic shielding assembly design reduces the volume of the transformer housing 100, thereby reducing the overall volume of the transformer.

[0032] Electrode layer 2 is laid on the inner surface of the shielding main layer 1, and the side of electrode layer 2 facing away from the shielding main layer 1 is a smooth surface. Due to the aforementioned stacking method, unevenness inevitably occurs on the inner surface of the stacked shielding main layer 1, which can lead to uneven electric field during operation. Therefore, by laying electrode layer 2 on the inner surface of the shielding main layer 1, and ensuring that the side of electrode layer 2 facing away from the shielding main layer 1 is smooth, the problem of uneven electric field caused by unevenness is overcome, thus preventing abnormal discharge phenomena.

[0033] According to the national standard GB6451, the transformer core and other metal parts of the transformer must be reliably grounded. The transformer housing 201 is multi-point grounded. The shielding layer 1, which is attached to the inner side of the transformer housing 201, can achieve multi-point grounding through the transformer housing 201, or it can be grounded independently through a corresponding grounding structure. For the electrode layer 2, it needs to achieve single-point reliable grounding through a separate grounding structure. Therefore, if the electrode layer 2 makes conductive contact with the shielding layer 2, multi-point grounding will occur, leading to intermittent breakdown discharge to ground and increasing eddy current losses. Therefore, an insulating layer 3 is laid between the shielding layer 1 and the electrode layer 2 to isolate them, preventing the electrode layer 2 from rusting and affecting the shielding layer 1, or vice versa. This also prevents the electrode layer 2 from connecting to the transformer housing 100 through the shielding layer 1 during use, thus avoiding intermittent breakdown discharge to ground and ensuring stable single-point grounding, thereby reducing eddy current losses.

[0034] The magnetic shielding component designed above is a multi-layer shielding structure consisting of a shielding main layer 1, an electrode layer 2, and an insulating layer 3. After three-dimensional simulation analysis and calculation of the structure, it can significantly reduce losses by 50kW to 80kW, thereby further reducing transformer losses.

[0035] Furthermore, the shielding assembly of this design has a concave arc-shaped surface 10 that adapts to the structure of coil 201, which ensures the safe operation of the transformer while reducing its size. Moreover, the stacking method used for the shielding main layer 1 of the shielding assembly differs from the common flat plate laying method. Combined with the design of its concave arc-shaped surface 10, it can better meet the mechanical strength requirements, achieve a more stable and reliable three-dimensional structure, and thus achieve technical and economic optimization.

[0036] The magnetic shielding components designed in this application are not limited to use in low-frequency transformers, but can also be used in power frequency or high-frequency transformers, including but not limited to oil-immersed transformers and other types of insulated transformers, without limitation.

[0037] The above is Embodiment 1 of a magnetic shielding component provided in this application. The following is Embodiment 2 of a magnetic shielding component provided in this application. Please refer to the following for details. Figures 1 to 4 .

[0038] Based on the solution of Embodiment 1 above:

[0039] Furthermore, the shielding sheet 11 is preferably a silicon steel sheet.

[0040] Furthermore, the electrode layer 2 is preferably a conductor layer or a semiconductor layer. Taking the conductor layer as an example, it can specifically be a copper foil layer, without limitation.

[0041] Furthermore, since a larger area of ​​electrode layer 2 will have a greater impact on the magnetic shielding performance of the shielding body layer 1, while a smaller area will affect the effectiveness of addressing electric field unevenness, the electrode layer is arranged at least on the inner surface of the shielding body layer 1 in an area 1.25 times the minimum distance d from the surface of coil 2. This minimum distance is determined based on the specific arrangement between the shielding body layer 1 and coil 201. Based on this design, the function of electrode layer 2 can be maximized while avoiding excessive impact on the magnetic shielding performance of the shielding body layer 1. It should be noted that the minimum area used for laying electrode layer 2 has its two side edges parallel to the central axis of the corresponding coil 201, and the distance between the minimum area and the central axis of coil 201 minus the radius of the coil is 1.25d. Simultaneously, the upper edge of this minimum area is located above the top of coil 201, and the vertical distance between the upper edge and the top of coil 201 is 1.25d. The lower edge of this minimum area is located below the bottom of coil 201, and the vertical distance between the lower edge and the bottom of coil 201 is 1.25d. Alternatively, it can be understood that the distance between the side edges of electrode layer 2 laid on the inner side of the shielding body layer 1 and the central axis of coil 201 minus the radius of coil 201 is ≥ 1.25d; the vertical distance from the upper edge of electrode layer 2 to the top of coil 201 is ≥ 1.25d; and the vertical distance from the lower edge of electrode layer 2 to the bottom of coil 201 is ≥ 1.25d.

[0042] Furthermore, if the area of ​​the electrode layer 2 to be laid is large, it is preferable to design the electrode layer 2 as a combination of multiple sub-electrode layers. An electrode layer 2 with a larger area formed by combining multiple sub-electrode layers has less impact on the shielding main layer 1 compared to a single electrode layer 2 with a larger area. Specifically, the area of ​​a single sub-electrode layer is determined by the conductivity of the electrode layer 2; the higher the conductivity, the smaller the area of ​​a single sub-electrode layer and the greater the number of sub-electrode layers.

[0043] Furthermore, the thickness of electrode layer 2 is determined by its own conductivity. The higher the conductivity, the smaller the corresponding thickness. Specifically, its own thickness should not exceed the penetration depth of the material used at the transformer's operating frequency, so that the magnetic leakage generated by the coil cannot pass through, causing the shielding main layer 1 to fail.

[0044] Furthermore, the insulating layer 3 can be formed by coating with insulating varnish.

[0045] The above provides a detailed description of a magnetic shielding component provided in this application. For those skilled in the art, based on the ideas of the embodiments of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A magnetic shielding assembly, characterized in that, It includes a shielding main layer (1), an electrode layer (2), and an insulating layer (3); The shielding main layer (1) is formed by stacking multiple shielding sheets (11) in its height direction. The inner side of the shielding main layer (1) has a concave arc surface (10), which faces the coil (201). The electrode layer (2) is laid on the inner side of the shielding main body layer (1), and the side of the electrode layer (2) facing away from the shielding main body layer (1) is a smooth surface; The insulating layer (3) is laid between the shielding main layer (1) and the electrode layer (2) to isolate the shielding main layer (1) from the electrode layer (2).

2. A magnetic shielding assembly according to claim 1, characterized in that, The shielding sheet (11) is a silicon steel sheet.

3. A magnetic shielding assembly according to claim 1, characterized in that, The electrode layer (2) is a conductor layer or a semiconductor layer.

4. A magnetic shielding assembly according to claim 1, characterized in that, The area of ​​the electrode layer (2) is smaller than the area of ​​the inner side of the shielding body layer (1).

5. A magnetic shielding assembly according to claim 1, characterized in that, The electrode layer (2) is formed by assembling multiple sub-electrode layers.

6. A magnetic shielding assembly according to claim 1, characterized in that, The insulating layer (3) is an insulating varnish layer.

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