CN115763018A - Magnetic shielding assembly - Google Patents

Abstract

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

Description

Magnetic shielding assembly

Technical Field

The application relates to the technical field of power transmission equipment, in particular to a magnetic shielding assembly and a transformer.

Background

With the construction of a novel power system and the development of a high-voltage large-capacity flexible alternating-current and direct-current transmission technology, transformer equipment tends to have the characteristics of large capacity, high voltage, large size and the like more and more, particularly in recent years, flexible low-frequency transmission gradually becomes a hot point of engineering technology due to the technical and economic advantages of low loss and the like, an iron core and size of a low-frequency transformer with the same voltage grade and capacity are obviously larger than that of a power-frequency transformer, and magnetic leakage is increased. Therefore, with the application of high-voltage large-capacity transformers and low-frequency transformers, how to realize low loss, low temperature rise and long-term safe and reliable operation of the transformers under the condition of meeting the transportation size requirements of the transformers is the most concerned technical problem in the transformer industry.

The largest stray losses in transformers result from: and the leakage magnetic field generated by the current in the transformer coil and the lead wire, namely the leakage magnetic loss of the transformer. Therefore, magnetic shielding or electric shielding is commonly adopted on a transformer oil tank to inhibit leakage loss, but the existing method for inhibiting leakage loss still has some defects:

for example, chinese patent publication No. CN211654522U discloses a transformer tank structure satisfying the conditions of railway transportation, and its magnetic shielding mode is copper shielding + insulating paper. The mode is influenced by the factors that the price of the copper material gradually rises due to continuous shortage of resources and the factors that the requirement of the large-sized transformer on the shielding material is large, so that the manufacturing cost of the transformer is higher and higher, and the insulating paper is not durable and is not easy to age.

Further, as shown in chinese patent No. CN2831360Y, an active field magnetic shielding oil immersed transformer is disclosed, wherein the magnetic shielding means is to use a plurality of thin silicon steel sheets stacked together along the thickness direction to form the width of the magnetic shielding wall. The method does not consider that the silicon steel sheets are not flat in the stacking process, and abnormal discharge phenomena (particularly in a high-voltage transformer) are easily caused when single silicon steel sheets protrude.

It can be seen from the above that, at present, the effect of reducing the transformer loss still needs to be further improved, and the single loss reduction effect cannot realize the technical and economic optimization. How to further reduce transformer loss and simultaneously reduce transformer volume, and guarantee the safe and reliable operation of equipment, realize technical economy optimization becomes the problem that needs to solve urgently.

Disclosure of Invention

In view of this, the present application aims to provide a magnetic shielding assembly, which can further reduce transformer loss and simultaneously reduce transformer volume, and realize technical economic optimization.

In order to achieve the above technical object, the present application provides a magnetic shield assembly including a shield main body layer, an electrode layer, and an insulating layer;

the shielding main body layer is formed by stacking a plurality of shielding sheets in the height direction, an inner concave arc surface is arranged on the inner side surface of the shielding main body layer, and the inner concave arc surface is arranged facing the coil;

the electrode layer is laid on the inner side surface of the shielding main body layer, and one surface of the electrode layer, which is back to the shielding main body layer, is a smooth surface;

the insulating layer is laid between the shielding main body layer and the electrode layer and used for isolating the shielding main body layer from the electrode layer.

Furthermore, the shielding plate is a silicon steel plate.

Further, the electrode layer is a conductor layer or a semiconductor layer.

Further, the area of the electrode layer is smaller than that of the inner side face of the shielding main body layer.

Further, the electrode layer is formed by a plurality of sub-electrode layer groups.

Further, the insulating layer is an insulating paint layer.

According to the magnetic shielding assembly, the shielding main body layer in the magnetic shielding assembly is designed to be formed by overlapping the plurality of shielding sheets in the height direction of the shielding main body layer, namely the thickness of each shielding sheet after accumulation and the height of the shielding main body layer are obtained, and therefore magnetic leakage generated by current in the coil and the lead can be effectively absorbed. And set up the indent curved surface towards the coil setting on shielding main part layer medial surface, make and satisfy under the condition of insulating safe distance between shielding main part layer and the coil, adaptation coil shape that can be better, shielding subassembly under this design is when cooperating with the coil, the volume that it encloses accounts for is compared in traditional rectangle structural design littleer, the transformer box of laminating with it like this also can process into the shape of looks adaptation, thereby have a smaller volume, simultaneously because the design of arc structure also makes the transformer box have better structural strength. Moreover, the electrode layer is laid on the inner side face of the shielding main body layer, and the surface, back to the shielding main body layer, of the electrode layer is a smooth surface, so that the inner side face of the shielding main body layer formed by stacking and stacking becomes flat, the condition of uneven electric field caused by unevenness is overcome, and abnormal discharge is avoided. Meanwhile, an insulating layer for isolation is arranged between the electrode layer and the shielding main body layer, so that the electrode layer is prevented from rusting to influence the shielding main body layer, or the shielding main body layer is rusted to influence the electrode layer, and meanwhile, the electrode layer is prevented from generating intermittent breakdown discharge to the ground, and further the eddy current loss is reduced. The magnetic shielding assembly with the design can further reduce transformer loss and the size of the transformer, and realizes technical and economic optimization.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.

FIG. 1 is a shield body layer structure view of a magnetic shield assembly provided herein;

fig. 2 is a view of a single shield sheet structure of a magnetic shield assembly provided in the present application;

fig. 3 is a schematic view of a mating structure between a shielding main body layer and a coil of a magnetic shielding assembly provided in the present application;

FIG. 4 is a partial cross-sectional view of a magnetic shield assembly provided herein applied to a transformer tank;

in the figure: 1. a shield body layer; 10. an inner concave arc-shaped surface; 11. a shielding sheet; 2. an electrode layer; 3. an insulating layer; 100. a transformer tank body; 201. and a coil.

Detailed Description

The technical solutions of the embodiments of the present application will be described clearly and completely with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making creative efforts belong to the protection scope of the embodiments in the present application.

In the description of the embodiments of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience in describing the embodiments of the present application and simplifying the description, but do not indicate or imply that the referred devices or elements must have specific orientations, be configured in specific orientations, and operate, and thus, should not be construed as limiting the embodiments of the present application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the embodiments of the present application, it should be noted that the terms "mounted," "connected," and "connected" are used broadly and are defined as, for example, a fixed connection, an exchangeable connection, an integrated connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection through an intermediate medium, and a communication between two elements, unless otherwise explicitly stated or limited. Specific meanings of the above terms in the embodiments of the present application can be understood as specific cases by those of ordinary skill in the art.

The embodiment of the application discloses a magnetic shielding assembly.

Referring to fig. 1 to 4, an embodiment of a magnetic shield assembly provided in an embodiment of the present application includes:

a shield main body layer 1, an electrode layer 2, and an insulating layer 3.

The shielding main body layer 1 is formed by stacking a plurality of shielding sheets 11 as shown in fig. 2 in the height direction of the shielding main body layer 1, and this stacking design, that is, the thickness of each shielding sheet 11 after stacking and the height of the shielding main body layer 1, may also be understood as stacking the shielding sheets 11 perpendicular to the wall surface of the transformer box 100 in the vertical direction to obtain the shielding main body layer 1 of the design, and by such stacking design, magnetic leakage generated by current in the coil 201 and the lead in the transformer can be absorbed more effectively.

Have indent arc face 10 on the medial surface of shielding main part layer 1, this indent arc face 10 is the cylinder cambered surface, set up towards coil 201, this design makes and satisfies under the condition of insulating safe distance between shielding main part layer 1 and the coil 201, better adaptation coil 201 shape, shielding subassembly under this design is when cooperating with coil 201, the volume that it encloses accounts for is compared in traditional rectangle structural design littleer, the transformer box 100 of laminating with it like this also can process into the shape of looks adaptation, thereby have littleer volume, simultaneously because the design of arc structure also makes transformer box 100 have better structural strength. Overall, the design of the magnetic shielding assembly can reduce the volume of the transformer tank 100 combined with the magnetic shielding assembly, thereby reducing the overall volume of the transformer.

The electrode layer 2 is laid on the inner side surface of the shielding main body layer 1, and one surface of the electrode layer 2, which is back to the shielding main body layer 1, is a smooth surface. Due to the adoption of the stacking mode, the inner side surface of the shielding main body layer 1 formed by stacking is inevitably uneven, and the problem of uneven electric field caused by the uneven condition in the running process can be caused. Therefore, the electrode layer 2 is laid on the inner side surface of the shield main body layer 1, and the surface of the electrode layer 2, which is opposite to the shield main body layer 1, is a smooth surface, so that the problem of non-uniform electric field caused by unevenness is solved, and abnormal discharge caused by the problem is avoided.

According to the requirement of the national standard GB6451, the iron core and other transformer metal parts of the transformer need to be reliably grounded, wherein the transformer box 201 is grounded in multiple points, the shielding main body layer 1 attached to the inner side surface of the transformer box 201 can realize the grounding in multiple points through the transformer box 201, and can also realize the grounding independently through a corresponding grounding structure. For the electrode layer 2, it is necessary to realize reliable single-point grounding through a separate grounding structure, and therefore, if the electrode layer 2 is in conductive contact with the shielding main body layer 2, multipoint grounding occurs, and then an intermittent ground breakdown discharge occurs, so as to increase eddy current loss, therefore, the insulating layer 3 is laid between the shielding main body layer 1 and the electrode layer 2, and is used for isolating the shielding main body layer 1 and the electrode layer 2, so as to prevent the electrode layer 2 from rusting and affecting the shielding main body layer 1, or the shielding main body layer 1 from rusting and affecting the electrode layer 2, and at the same time, it is avoided that when in use, the electrode layer 2 is connected with the transformer box 100 through the shielding main body layer 1, and intermittent ground breakdown discharge occurs, so as to ensure that it can stably perform single-point grounding, and further reduce eddy current loss.

The magnetic shielding assembly is a multi-layer shielding structure consisting of a shielding main body layer 1, an electrode layer 2 and an insulating layer 3, and through three-dimensional simulation analysis and calculation of the structure, the loss can be greatly reduced by 50 kW-80 kW, and the effect of further reducing the transformer loss is realized.

Moreover, the shielding component of this design has the interior concave arc face 10 of adaptation coil 201 structure, can reduce the transformer volume when guaranteeing the transformer safe operation. Moreover, the stacking mode adopted by the shielding main body layer 1 of the shielding assembly is different from common flat plate laying, and the design of the concave arc-shaped surface 10 is combined, so that the mechanical strength requirement can be better met, a more stable and firm three-dimensional structure is realized, and further, the technical economy optimization is realized.

The magnetic shielding component designed by the application is not limited to be used by a low-frequency transformer, and can also be used for a power-frequency or high-frequency transformer, specifically including but not limited to oil-immersed transformers, other insulation type transformers and the like, without limitation.

The above is a first embodiment of a magnetic shield assembly provided in the embodiments of the present application, and the following is a second embodiment of a magnetic shield assembly provided in the embodiments of the present application, specifically referring to fig. 1 to 4.

The scheme based on the first embodiment is as follows:

further, the shield sheet 11 is preferably a silicon steel sheet.

Further, the electrode layer 2 is preferably a conductive layer or a semiconductor layer, and the conductive layer is taken as an example, and may be specifically a copper foil layer, without limitation.

Further, since the larger the area of the electrode layer 2 is laid, the larger the influence of the area on the magnetic shielding performance of the shield main body layer 1 is, and of course, if the area is too small, the effect of resolving the electric field unevenness is influenced, and therefore, the electrode layer is laid at least in the region of the inner side surface of the shield main body layer 1 at a minimum distance d of 1.25 times from the surface of the coil 2. The minimum distance is determined according to the specific layout condition between the shielding main body layer 1 and the coil 201, and based on the design, the function of the electrode layer 2 can be ensured to the maximum extent, and meanwhile, the excessive influence on the magnetic shielding performance of the shielding main body layer 1 is avoided. It should be noted that, in the minimum area for laying the electrode layer 2, edge lines on two sides of the minimum area are parallel to the central axis of the corresponding coil 201, and the distance between the edge lines and the central axis of the coil 201, namely the radius of the coil, is also 1.25d, meanwhile, an upper edge line of the minimum area is located above the top of the coil 201 and is 1.25d away from the top of the coil 201 in the vertical direction, and a lower edge line of the minimum area is located below the bottom of the coil 201 and is 1.25d away from the bottom of the coil 201 in the vertical direction. It can also be understood that the distance between the side edge line of the electrode layer 2 laid on the inner side surface of the shielding main body layer 1 and the central axis of the coil 201-the radius of the coil 201 is more than or equal to 1.25d, the distance between the upper edge of the electrode layer 2 and the top of the coil 201 in the vertical direction is more than or equal to 1.25d, and the distance between the lower edge of the electrode layer 2 and the bottom of the coil 201 in the vertical direction is more than or equal to 1.25d.

Further, if the electrode layer 2 to be laid has a large area, it is preferable to design the electrode layer 2 to be formed by a plurality of sub-electrode layer pieces. The electrode layer 2 having a large area formed by a plurality of sub-electrode layer patches has less influence on the shield main body layer 1 than the electrode layer 2 having a large area alone. The area of the individual sub-electrode layers is determined by the conductivity of the electrode layer 2, the larger the conductivity, the smaller the area of the individual sub-electrode layers and the larger the number.

Further, the thickness of the electrode layer 2 is determined by the conductivity of the electrode layer, the larger the conductivity is, the smaller the thickness of the electrode layer is laid correspondingly, the specific thickness of the electrode layer should not exceed the penetration depth of the material used by the electrode layer under the working frequency of the transformer, and further the magnetic leakage generated by the coil cannot penetrate through the electrode layer, so that the shielding main body layer 1 fails.

Further, the insulating layer 3 may be formed of a coated insulating varnish.

While the magnetic shield assembly provided in the present application has been described in detail, it will be apparent to those skilled in the art that the embodiments and applications of the magnetic shield assembly can be modified according to the spirit of the present application.

Claims (6)

1. Magnetic shield assembly, characterized by comprising a shield main body layer (1), an electrode layer (2) and an insulating layer (3);

the shielding main body layer (1) is formed by stacking a plurality of shielding sheets (11) in the height direction, an inner concave arc-shaped surface (10) is arranged on the inner side surface of the shielding main body layer (1), and the inner concave arc-shaped surface (10) faces the coil (201);

the electrode layer (2) is laid on the inner side surface of the shielding main body layer (1), and one surface of the electrode layer (2) back to the shielding main body layer (1) is a smooth surface;

the insulating layer (3) is laid between the shielding main body layer (1) and the electrode layer (2) and used for isolating the shielding main body layer (1) from the electrode layer (2).

2. Magnetic shield assembly according to claim 1, in which the shield sheet (11) is a sheet of silicon steel.

3. Magnetic shield assembly according to claim 1, characterized in that the electrode layer (2) is a conductor layer or a semiconductor layer.

4. Magnetic shield 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 shield body layer (1).

5. Magnetic shield assembly according to claim 1, characterized in that the electrode layer (2) is formed by a plurality of sub-electrode layer tiles.

6. Magnetic shield assembly according to claim 1, characterized in that the insulating layer (3) is an insulating lacquer layer.

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