Plate-type magnetic shielding structure with low eddy current loss and installation method thereof

Abstract

The invention discloses a plate-type magnetic shielding structure with low eddy current loss and an installation method thereof, and belongs to the technical field of transformer structures.The plate-type magnetic shielding structure comprises a plurality of silicon steel sheets, and the silicon steel sheets are stacked in the direction parallel to the wall of a transformer box to form a magnetic shielding body; and a stepped structure is formed between the silicon steel sheets at the highest incident flux density. The problem that an existing magnetic shielding structure is too high in eddy current loss can be solved.

Description

Technical Field

[0001] The invention belongs to the technical field of transformer structures, and in particular relates to a plate-type magnetic shielding structure with low eddy current loss and a mounting method thereof. Background Art

[0002] With the continuous development of social economy, people's demand for electric energy is increasing day by day, and large-capacity and high-voltage transformers have become extremely critical electrical equipment. As an indispensable power conversion device in the power system, the performance of the transformer directly affects the stability and efficiency of the entire power grid. With the continuous growth of electricity demand, more complex electromagnetic field distribution problems have been brought about, especially the significant increase in leakage magnetic loss. Leakage magnetic loss is mainly caused by the leakage magnetic field outside the transformer core. This part of the magnetic field fails to completely pass through the core to form a closed loop, but leaks into the transformer tank and surrounding structures, resulting in energy loss and temperature rise. In the long run, this will not only reduce the energy efficiency of the transformer, but may also accelerate the aging of the insulation material, shorten the service life of the equipment, and even cause safety accidents.

[0003] The increase in transformer capacity and voltage level has brought great challenges to the control of leakage magnetic loss. The leakage magnetic field is generated by the current in the transformer coil and lead wire. The leakage magnetic field and its distribution determine the short-circuit impedance of the transformer, the mechanical force of the winding and the stray loss of the structural parts. The concentration of the leakage magnetic field will also cause local overheating, leading to thermal aging of the insulation material and affecting the service life of the transformer. When the incident magnetic density on the surface of the transformer tank is high to a certain extent, a magnetic shield should be laid to provide a low magnetic resistance path for the leakage magnetic flux to prevent the leakage magnetic flux from directly entering the tank wall and generating a large amount of stray losses.

[0004] Traditional plate-type magnetic shielding often faces the problem of excessive eddy current loss when dealing with areas with high leakage magnetic density. Eddy current loss is the heat loss caused by eddy currents induced by magnetic materials in a changing magnetic field. It not only reduces the effectiveness of magnetic shielding, but may also cause noise, material degradation and other adverse effects due to local overheating. Especially in areas with the highest leakage magnetic density of transformers, such as winding ends and tank corners, the eddy current loss problem is particularly prominent. Excessive eddy current loss can easily cause local overheating, abnormal noise and other problems. Summary of the invention

[0005] The object of the present invention is to provide a plate-type magnetic shielding structure with low eddy current loss and an installation method thereof, so as to solve the problem of excessively high eddy current loss in the existing magnetic shielding structure.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, a plate-type magnetic shielding structure with low eddy current loss includes a plurality of silicon steel sheets, which are stacked in a direction parallel to a transformer box wall to form a magnetic shielding body, and a stepped structure is formed between the silicon steel sheets at the highest point of incident magnetic flux density.

[0007] In some embodiments, a plurality of magnetic shielding bodies are closely arranged along the wall surface of the transformer tank.

[0008] In some embodiments, each layer surface of the stepped structure is a parallelogram, and the top layer surface of the magnetic shielding body is a trapezoid.

[0009] In some embodiments, there are gaps between adjacent magnetic shielding bodies.

[0010] In some embodiments, the surface areas of the silicon steel sheets in the bottom layer to the top layer in the magnetic shielding body decrease sequentially.

[0011] A second aspect. A method for installing a plate-type magnetic shielding structure with low eddy current loss, based on the plate-type magnetic shielding structure, comprises the following steps: After cutting multiple silicon steel sheets at a preset angle, they are stacked in a step-by-step manner in a direction parallel to the transformer box wall to obtain a magnetic shielding body; Several of the magnetic shielding bodies are installed on the wall surface of the transformer box and arranged closely together to complete the installation of the plate-type magnetic shielding structure.

[0012] In some embodiments, a preset gap is left between adjacent magnetic shielding bodies when they are arranged closely together.

[0013] In some implementations, after the transformer magnetic leakage value is confirmed, the number of the silicon steel sheets is adjusted according to the transformer magnetic leakage value, thereby adjusting the thickness of the magnetic shielding body.

[0014] In some implementations, after the distance to the transformer box wall is confirmed, the number of the magnetic shielding bodies is adjusted according to the distance to the transformer box wall, thereby adjusting the number of the adjacently arranged columns.

[0015] In some embodiments, the silicon steel sheets are cut obliquely at the same preset angle.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention forms a magnetic shielding body by stacking multiple silicon steel sheets in a direction parallel to the transformer box wall, and forms a stepped structure at the highest point of the incident magnetic flux density, thereby reducing the incident area and effectively guiding the leakage magnetic flux to the rear silicon steel sheet to reduce the eddy current loss of the magnetic shielding itself, avoid overheating, and significantly reduce the eddy current loss. The silicon steel sheet has high resistivity and good magnetic conductivity, and can effectively suppress the eddy current generated by the leakage magnetic flux in the shielding layer, thereby reducing energy loss. The stepped structure enables the magnetic shielding body to better adapt to the distribution characteristics of the transformer leakage magnetic field and improve the shielding effect.

[0017] The surface of each layer of the stepped structure of the present invention is a parallelogram, and the top surface of the magnetic shielding body is a trapezoid. The surfaces of the parallelogram and trapezoidal structures can more effectively guide the distribution of magnetic lines of force, making the magnetic density collection process more uniform. Compared with the traditional structure, this design can significantly reduce the loss and waste of magnetic lines of force, thereby improving the utilization efficiency of magnetic energy.

[0018] The present invention adjusts the number of silicon steel sheets according to the magnetic leakage value of the transformer, and then adjusts the thickness of the magnetic shielding body. At the same time, the number of magnetic shielding bodies is adjusted according to the distance from the transformer box wall, and then the number of adjacent columns is adjusted. By adjusting the number of silicon steel sheets and the number of adjacent columns, the shielding requirements of different transformers can be met, and the invention is widely used in transformers of various types and specifications. Therefore, while ensuring the shielding performance, the present invention can flexibly reduce the use of silicon steel sheets and reduce material costs.

[0019] The surface areas of the silicon steel sheets from the bottom layer to the top layer in the magnetic shielding body of the present invention decrease successively. The plate-type magnetic shielding structure is formed by stacking silicon steel sheets of different lengths and sizes, providing a low magnetic resistance path for stray magnetic flux and eliminating magnetic shielding saturation caused by leakage magnetic concentration.

[0020] The present invention performs oblique cutting at the same preset angle when processing silicon steel sheets, and the process operation is simple. The operator only needs to perform oblique cutting according to the preset angle, and there is no need to frequently adjust the cutting angle, thereby greatly improving the work efficiency. At the same time, due to the consistency of the cutting angle, the stability and reliability of the processing quality of the silicon steel sheet are also guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A front view of a plate-type magnetic shielding structure with low eddy current loss provided by an embodiment of the present invention; Figure 2 A schematic diagram of closely arranged magnetic shielding bodies provided by an embodiment of the present invention; Figure 3 A schematic diagram of a plate-type magnetic shielding structure formed after being arranged closely together according to an embodiment of the present invention.

[0022] 1. Magnetic shielding bottom layer; 2. Magnetic shielding middle layer; 3. Magnetic shielding upper layer. DETAILED DESCRIPTION

[0023] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the specific embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0024] In the following description, a large number of details are given to provide a more thorough understanding of the present disclosure. However, it is obvious to those skilled in the art that the present disclosure can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present disclosure, some technical features known in the art are not described; that is, all features of actual embodiments are not described here, and well-known functions and structures are not described in detail.

[0025] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present disclosure, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. And when the second element, component, region, layer or part is discussed, it does not indicate that the present disclosure necessarily has the first element, component, region, layer or part.

[0026] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be a limitation of the present disclosure. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0027] With the development of modern power systems, large-capacity, high-voltage transformers have become key equipment in power transmission and distribution. However, the increase in transformer capacity and voltage level has made the problem of magnetic leakage loss more prominent, posing a severe challenge to the energy efficiency and operational stability of the transformer. The leakage magnetic field will not only increase the short-circuit impedance of the transformer and the mechanical force of the winding, but may also cause stray losses in the structural parts. In severe cases, it may even cause local overheating, accelerate the aging of the insulation material, and affect the service life of the transformer.

[0028] In order to effectively control the leakage magnetic loss, magnetic shielding technology came into being. The magnetic shielding structure effectively prevents the leakage magnetic flux from directly entering the transformer tank wall by providing a low magnetic resistance path for the leakage magnetic flux, thereby significantly reducing stray losses. Among the many magnetic shielding structures, plate-type magnetic shielding is widely used due to its simple structure and low cost. However, traditional plate-type magnetic shielding often has the problem of excessive eddy current loss in areas with high leakage magnetic density, which not only reduces the effectiveness of magnetic shielding, but may also cause adverse phenomena such as overheating and noise.

[0029] In view of the above problems, this embodiment proposes a low eddy current loss plate-type magnetic shielding structure and its installation method. By optimizing the structural design and material selection of the magnetic shielding, and cutting the silicon steel sheet at a specific angle, this embodiment can meet the high requirements of modern power systems for transformer energy efficiency and operation stability. The following will introduce in detail the embodiment of this magnetic shielding structure and its installation method.

[0030] Embodiment 1 This embodiment provides a plate-type magnetic shielding structure with low eddy current loss, which is mainly used for transformer box wall. By optimizing the structure and material use of the magnetic shielding, its absorption capacity for leakage magnetic flux is improved, while its own eddy current loss is reduced.

[0031] The plate-type magnetic shielding structure uses silicon steel sheets as the main material because of its high resistivity and good magnetic conductivity, which can effectively reduce eddy current losses. The silicon steel sheets are cut at a uniform angle of 30 degrees to obtain silicon steel sheets of different sizes and shapes, such as Figure 1As shown, after cutting three silicon steel sheets in this embodiment, they are stacked in order from large to small to form a magnetic shielding body, which includes a magnetic shielding bottom layer 1, a magnetic shielding middle layer 2 and a magnetic shielding upper layer 3, which is a stepped structure. This structure can provide a low magnetic resistance path for stray magnetic flux and effectively eliminate the magnetic shielding saturation phenomenon caused by leakage magnetic concentration. The magnetic shielding upper layer 3 and the magnetic shielding middle layer 2 form a parallelogram at the step, and the magnetic shielding upper layer 3 forms a trapezoid, which can make the magnetic density collection more uniform and improve the performance of the magnetic shielding.

[0032] like Figure 2 and Figure 3 As shown, the magnetic shielding bodies are arranged closely one by one on the wall of the transformer box, and appropriate gaps are left between adjacent magnetic shielding bodies to ensure good heat dissipation and avoid mutual interference. The thickness of the magnetic shielding body is adjusted according to the leakage magnetic size of the transformer, and the number of silicon steel sheets is adjusted to change the thickness of the magnetic shielding body. The number of columns of the magnetic shielding bodies arranged closely is adjusted according to the distance from the transformer box wall to achieve the best shielding effect.

[0033] The stepped plate-type magnetic shielding structure provided in this embodiment not only reduces the use of silicon steel sheets and reduces material costs, but also can enhance the magnetic shielding's ability to absorb leakage magnetic flux by providing a low magnetic resistance path. At the highest point of the incident magnetic flux density of the magnetic shielding, the silicon steel sheets are divided and stacked in a stepped form, which can reduce the incident area, reduce the eddy current loss of the magnetic shielding itself, and avoid overheating.

[0034] Based on the above-mentioned plate-type magnetic shielding structure with low eddy current loss, this embodiment provides an installation method of the plate-type magnetic shielding structure with low eddy current loss, including the following steps: S1, using an oblique blade cutting machine to cut the silicon steel sheet at an angle of 30 degrees to obtain silicon steel sheets of different sizes; S2, stacking the cut silicon steel sheets of different sizes in order from large to small in a direction parallel to the transformer box wall to form a stepped magnetic shielding body with different thicknesses, the magnetic shielding body comprising a magnetic shielding bottom layer 1, a magnetic shielding middle layer 2 and a magnetic shielding upper layer 3. During the stacking process, close contact between the silicon steel sheets must be ensured to improve the shielding effect of the magnetic shielding; S3, the stacked magnetic shielding bodies are arranged closely one by one on the wall of the transformer box, with appropriate gaps left between adjacent magnetic shielding bodies, to complete the installation of the plate-type magnetic shielding structure.

[0035] This embodiment performs segmentation at the highest point of the incident magnetic flux density of the plate-type magnetic shield, which can reduce the incident area, reduce eddy current losses, and effectively guide the leakage magnetic flux to the rear silicon steel sheet.

[0036] Embodiment 2 This embodiment introduces a low eddy current loss plate-type magnetic shielding structure designed for the transformer box wall. This structure significantly improves its absorption efficiency of leakage magnetic flux and greatly reduces eddy current loss by optimizing the structure and material selection of the magnetic shielding.

[0037] The core material of this plate-type magnetic shielding structure is silicon steel sheet. Thanks to its excellent high resistivity and magnetic conductivity, silicon steel sheet can effectively suppress the generation of eddy currents, thereby reducing energy loss. During the manufacturing process, the silicon steel sheets are uniformly cut at a 45-degree angle to obtain a series of silicon steel sheets of different sizes. This embodiment selects five silicon steel sheets, which are stacked in order from large to small in size to form a stepped magnetic shielding body. The stepped design provides a smooth low magnetic resistance path for stray magnetic flux, effectively avoiding the problem of magnetic shielding saturation caused by leakage magnetic concentration. In particular, a parallelogram structure is formed at the intersection of the steps. This design further optimizes the distribution of magnetic density and improves the overall performance of the magnetic shielding.

[0038] The magnetic shielding bodies are closely arranged on the transformer box wall, and appropriate gaps are maintained between adjacent magnetic shielding bodies to ensure good heat dissipation and prevent mutual electromagnetic interference. The thickness of the magnetic shielding body can be adjusted according to the magnetic leakage strength of the transformer, and its thickness can be changed by increasing or decreasing the number of silicon steel sheets. At the same time, the number of magnetic shielding bodies arranged on the transformer box wall is also optimized according to actual needs to achieve the best shielding effect.

[0039] Compared with the first embodiment, the stepped plate-type magnetic shielding structure of this embodiment increases the amount of silicon steel sheets used, significantly enhancing the magnetic shielding's ability to absorb leakage magnetic flux. In particular, in the area where the incident magnetic flux density of the magnetic shielding is the highest, the stepped segmentation and superposition design effectively reduces the incident area, further reduces the eddy current loss, and thus avoids the occurrence of overheating.

[0040] Based on the above-mentioned plate-type magnetic shielding structure with low eddy current loss, this embodiment also provides a corresponding installation method, and the specific steps are as follows: S1: Use an oblique blade cutting machine to precisely cut the silicon steel sheet at a 45-degree angle to obtain the silicon steel sheet of the required size and shape.

[0041] S2: Stack the cut silicon steel sheets in order of size from large to small, parallel to the transformer box wall, to form a stepped magnetic shielding body with different thicknesses. During the stacking process, it is necessary to ensure that the silicon steel sheets fit closely to improve the effectiveness of the magnetic shielding.

[0042] S3: Arrange the stacked magnetic shielding bodies closely one by one on the transformer box wall, and maintain appropriate gaps between adjacent magnetic shielding bodies to ensure good heat dissipation and avoid electromagnetic interference. At this point, the installation of the plate-type magnetic shielding structure is completed.

[0043] This embodiment not only reduces eddy current losses but also effectively guides the leakage magnetic flow to the rear silicon steel sheet area, thereby achieving a more efficient magnetic shielding effect, by cleverly dividing and superimposing the area with the highest incident magnetic density in the magnetic shielding.

[0044] In summary, this embodiment proposes an innovative low eddy current loss plate-type magnetic shielding structure and its installation method, which effectively reduces eddy current loss and significantly improves leakage magnetic absorption capacity by optimizing the structural design and material selection of the magnetic shielding, and performing oblique knife cutting on the silicon steel sheet at a specific angle.

[0045] (1) Structural design optimization The plate-type magnetic shielding structure of this embodiment adopts a stepped design, by stacking silicon steel sheets of different sizes in order from large to small, to form a stepped magnetic shielding body with different thicknesses. This design not only provides a smoother low magnetic resistance path for leakage flux, effectively avoiding the problem of magnetic shielding saturation caused by leakage flux concentration, but also further optimizes the distribution of magnetic density through the parallelogram structure formed at the intersection of the steps, thereby improving the overall performance of the magnetic shielding.

[0046] (2) Material selection and cutting process As the core material of magnetic shielding, the performance of silicon steel sheet directly affects the effect of magnetic shielding. This embodiment selects high-quality silicon steel sheets with high resistivity and good magnetic conductivity to effectively suppress the generation of eddy currents. In addition, during the manufacturing process, the silicon steel sheets are uniformly cut at a specific angle (such as 30 degrees or 45 degrees) to obtain silicon steel sheets of different sizes and shapes. This cutting method not only helps to optimize the structural layout of the magnetic shielding, but also disperses the magnetic field to a certain extent and reduces the formation of eddy currents.

[0047] (3) Innovation in installation methods During the installation of the magnetic shield, the present embodiment first determines the thickness and number of columns of the magnetic shield body through precise measurement and calculation to ensure the best shielding effect. Secondly, when stacking silicon steel sheets, ensure that the silicon steel sheets fit closely to improve the effectiveness of the magnetic shield. Finally, when the magnetic shield body is installed on the wall of the transformer box, an appropriate gap is left between adjacent magnetic shield bodies to ensure good heat dissipation and avoid electromagnetic interference.

[0048] The low eddy current loss plate-type magnetic shielding structure and its installation method proposed in this embodiment not only solve the problem of excessive eddy current loss of traditional plate-type magnetic shielding in high leakage magnetic density areas, but also significantly improve the effectiveness and reliability of magnetic shielding through structural optimization and material innovation. It helps to improve the energy efficiency and operation stability of transformers, extend the service life of equipment, and reduce maintenance costs, which is of great significance to promoting the sustainable development of the power industry.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A plate-type magnetic shielding structure with low eddy current loss, characterized in that: The invention comprises a plurality of silicon steel sheets, which are stacked in a direction parallel to the wall of the transformer box to form a magnetic shielding body, and a stepped structure is formed between the silicon steel sheets at the highest point of the incident magnetic flux density.

2. A plate-type magnetic shielding structure with low eddy current loss according to claim 1, characterized in that: A plurality of magnetic shielding bodies are arranged closely along the wall surface of the transformer box.

3. A plate-type magnetic shielding structure with low eddy current loss according to claim 1, characterized in that: The surface of each layer of the stepped structure is a parallelogram, and the surface of the top layer of the magnetic shielding body is a trapezoid.

4. A plate-type magnetic shielding structure with low eddy current loss according to claim 1, characterized in that: There is a gap between adjacent magnetic shielding bodies.

5. A plate-type magnetic shielding structure with low eddy current loss according to claim 1, characterized in that: The surface areas of the silicon steel sheets in the bottom layer to the top layer in the magnetic shielding body decrease successively.

6. A method for installing a plate-type magnetic shielding structure with low eddy current loss, characterized in that: The plate-type magnetic shielding structure according to any one of claims 1 to 5 comprises the following steps: After cutting multiple silicon steel sheets at a preset angle, they are stacked in a step-by-step manner in a direction parallel to the transformer box wall to obtain a magnetic shielding body; Several of the magnetic shielding bodies are installed on the wall surface of the transformer box and arranged closely together to complete the installation of the plate-type magnetic shielding structure.

7. The installation method of a plate-type magnetic shielding structure with low eddy current loss according to claim 6, characterized in that: A preset gap is left between adjacent magnetic shielding bodies when they are arranged closely.

8. The method for installing a plate-type magnetic shielding structure with low eddy current loss according to claim 6, characterized in that: After confirming the transformer magnetic leakage value, the number of the silicon steel sheets is adjusted according to the transformer magnetic leakage value, and then the thickness of the magnetic shielding body is adjusted.

9. The method for installing a plate-type magnetic shielding structure with low eddy current loss according to claim 6, characterized in that: After confirming the distance to the transformer box wall, the number of the magnetic shielding bodies is adjusted according to the distance to the transformer box wall, thereby adjusting the number of the closely arranged columns.

10. The installation method of a plate-type magnetic shielding structure with low eddy current loss according to claim 6, characterized in that: The silicon steel sheets are cut obliquely at the same preset angle.

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