A dry-type transformer with a voltage class of 72.5 kV

Abstract

This invention provides a dry-type transformer (100) with a voltage rating of 72.5kV, comprising a high-voltage coil assembly (40), which includes: a conductor layer and an insulation layer, the conductor layer comprising a plurality of conductors (41) spaced apart along the axial direction of the iron core, the insulation layer being disposed on one side of the conductor layer along the radial direction of the iron core, and comprising a plurality of basic insulation layers (42) disposed close to each of the plurality of conductors and electrically insulating one side of the plurality of conductors in the radial direction; a plurality of reinforcing insulation layers (43) disposed away from the basic insulation layers and electrically insulating one side of the plurality of conductors in the radial direction, the axial height of the reinforcing insulation layers being greater than the axial height of the basic insulation layers; a supporting insulation layer (44) disposed away from the plurality of reinforcing insulation layers and electrically insulating one side of the plurality of conductors in the radial direction; and an epoxy resin component (45) forming an integral structure with the conductor layer and the insulation layer. The dry-type transformer of this invention can meet the insulation requirements.

Description

Technical Field

[0001] This invention relates to the field of transformer technology, and more particularly to a dry-type transformer with a voltage rating of 72.5kV. Background Technology

[0002] In power systems, transformers are the core components of substations. Generally, transformers can be classified into dry-type transformers and oil-immersed transformers according to their cooling method. Dry-type transformers are transformers in which the iron core and coils are not immersed in insulating liquid. They have advantages such as low power consumption, high efficiency, flame retardancy and explosion protection, no pollution, and maintenance-free operation, and are widely used in various industries.

[0003] Existing dry-type transformers typically employ a combination of air insulation and solid insulation in their insulation systems. However, the insulation class of dry-type transformers in the power market is often limited to voltage levels of 35kV and below. When higher voltage levels require insulation, increasing the thickness of the air and solid insulation in the dry-type transformer is often a direct and effective way to meet operational requirements. However, this increases material costs, weight, and loss parameters. Furthermore, in some applications, even increasing insulation thickness may not meet technical requirements. Therefore, for transformers with voltage levels above 35kV, oil-immersed transformers are generally preferred.

[0004] Therefore, existing dry-type transformers need to be improved to meet the operating requirements of higher voltage levels and provide more reliable options for the electricity market. Summary of the Invention

[0005] In view of this, the present invention proposes a dry-type transformer with a voltage level of 72.5kV to meet the current insulation requirements for transformer products with a voltage level of 72.5kV, and optimizes the structural design of the dry-type transformer.

[0006] Therefore, according to one aspect of the present invention, a dry-type transformer with a voltage rating of 72.5kV is provided, comprising: a core having an axial direction and a radial direction; a low-voltage coil assembly coaxially disposed around the core; and a high-voltage coil assembly coaxially disposed around the low-voltage coil assembly; wherein the high-voltage coil assembly comprises: a conductor layer and an insulating layer, the conductor layer comprising a plurality of conductors spaced apart along the axial direction, the insulating layer being disposed on one side of the conductor layer along the radial direction, wherein the insulating layer comprises: a plurality of basic insulating layers disposed close to each of the plurality of conductors and electrically insulating one side of the plurality of conductors along the radial direction; a plurality of reinforcing insulating layers disposed away from each of the plurality of conductors relative to the basic insulating layers and electrically insulating one side of the plurality of conductors along the radial direction, wherein the axial height of the reinforcing insulating layers is greater than the axial height of the basic insulating layers; and a supporting insulating layer disposed away from the plurality of conductors relative to the plurality of reinforcing insulating layers and electrically insulating one side of the plurality of conductors along the radial direction; and an epoxy resin component, the epoxy resin component, the conductor layer, and the insulating layer forming an integral structure.

[0007] According to one embodiment of the present invention, the supporting insulating layer is a multi-layer structure, and the multi-layer structure includes a mechanical support layer.

[0008] According to one embodiment of the present invention, a portion of the epoxy resin component is located between two adjacent layers in the multilayer structure.

[0009] According to one embodiment of the present invention, a plurality of insulating cylinders are provided between the low-voltage coil assembly and the high-voltage coil assembly, and adjacent insulating cylinders are spaced apart from each other by a certain gap.

[0010] According to one embodiment of the present invention, the dry-type transformer further includes an output terminal and a voltage regulating tap terminal, wherein the output terminal and the voltage regulating tap terminal are externally covered with an insulating protective component.

[0011] According to one embodiment of the present invention, the dry-type transformer further includes an upper clamp and a lower clamp, wherein the iron core, the low-voltage coil assembly and the high-voltage coil assembly are assembled between the upper clamp and the lower clamp, wherein the upper clamp and the lower clamp include rounded ends and curved portions forming arc shapes.

[0012] According to one embodiment of the present invention, the dry-type transformer further includes an insulating barrier located between the low-voltage coil assembly and the upper clamp and the lower clamp, and between the high-voltage coil assembly and the upper clamp and the lower clamp.

[0013] According to one embodiment of the present invention, any one of the base insulation layer, the reinforcing insulation layer, and the insulating cylinder is made of any one selected from the group consisting of polyethylene terephthalate, polyester film, polyester fiber nonwoven flexible composite foil, glass fiber prepreg, and epoxy resin, and the supporting insulation layer is made of any one or more selected from the group consisting of polyethylene terephthalate, polyester film, polyester fiber nonwoven flexible composite foil, glass fiber prepreg, and epoxy resin.

[0014] According to one embodiment of the present invention, the base insulation layer, the reinforcing insulation layer and the supporting insulation layer are made of different materials.

[0015] As can be seen from the above scheme, because the high-voltage coil assembly of the dry-type transformer of the present invention can include a multi-layered internal insulation design with multiple insulating materials, and a multi-gap insulation design is provided between the high-voltage coil assembly and the low-voltage coil assembly, the external energized structure is insulated in a fully insulated manner, the shape of the structural components is designed with blunted edges, and insulating partitions are provided between the low-voltage and high-voltage coil assemblies and the structural components, it can fully meet the insulation requirements of dry-type transformer products with a voltage level of 72.5kV, thus providing more reliable options for the power market. In addition, the dry-type transformer of the present invention integrates the advantages of ordinary dry-type transformers such as flame retardancy, explosion protection, and maintenance-free operation, and further optimizes the structural design of the dry-type transformer. Attached Figure Description

[0016] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which will make the above and other features and advantages of the present invention more apparent to those skilled in the art. In the drawings:

[0017] Figure 1 A schematic cross-sectional view of a dry-type transformer with a voltage rating of 72.5kV according to an embodiment of the present invention;

[0018] Figure 2 for Figure 1 A schematic partial cross-sectional view of the high-voltage coil assembly of the dry-type transformer shown.

[0019] Figure 3 for Figure 1 A magnified view of a portion of region A shown in the image.

[0020] The accompanying figure is labeled as follows:

[0021] 10 Iron Core

[0022] 21 Upper clamp

[0023] 22 Lower clamping parts

[0024] 23 end

[0025] 24. Bend

[0026] 30 Low-voltage coil assembly

[0027] 40 High-voltage coil assembly

[0028] 41 Conductors

[0029] 42 Basic Insulation Layer

[0030] 43. Reinforce the insulation layer

[0031] 44 Supporting insulation layer

[0032] 45 Epoxy Resin Parts

[0033] 50 Insulating Cylinder

[0034] 61 Outgoing terminal and voltage regulating tap terminal

[0035] 62 Insulation protection components

[0036] 100 dry-type transformer Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is further described in detail below through embodiments. Those skilled in the art should understand that these exemplary embodiments do not imply any limitation on the invention. Furthermore, features in the embodiments of the invention can be combined with each other unless otherwise specified. In different drawings, identical or similar components are indicated by the same reference numerals, and other components are omitted for brevity, but this does not mean that the 72.5kV dry-type transformer of the present invention cannot include other components. It should be understood that the dimensions, proportions, and number of components in the drawings are not intended to limit the invention.

[0038] The following is for reference. Figures 1 to 3 This invention describes a dry-type transformer with a voltage rating of 72.5 kV according to an embodiment of the present invention.

[0039] like Figure 1As shown, the dry-type transformer 100 of the present invention, with a voltage rating of 72.5kV, includes a core 10, a low-voltage coil assembly 30, and a high-voltage coil assembly 40. The core 10 has an axial direction X and a radial direction (not shown). The low-voltage coil assembly 30 is coaxially arranged around the core 10, and the high-voltage coil assembly 40 is coaxially arranged around the low-voltage coil assembly 30. This forms a coaxial nested structure with the core 10 inside, the low-voltage coil assembly 30 in the middle, and the high-voltage coil assembly 40 on the outside. The core 10 can be made of materials such as silicon steel sheets or amorphous alloy strips. The low-voltage coil assembly 30 can be made of pre-impregnated insulating material, epoxy resin, copper (aluminum) foil (wire), etc., while the high-voltage coil assembly 40 can be made of epoxy resin, copper (aluminum) foil (wire), insulating film, pre-impregnated insulating material, etc. However, the present invention is not limited to these materials, and any suitable materials known in the art can be used to form the core 10, the low-voltage coil assembly 30, and the high-voltage coil assembly 40. It should be noted that in Figure 1 In the dry-type transformer shown, the low-voltage coil assembly 30 includes upper and lower low-voltage coils, and the high-voltage coil assembly 40 includes upper and lower high-voltage coils. However, the present invention is not limited to this, but can be applied to any type of dry-type transformer.

[0040] like Figure 2As shown, the high-voltage coil assembly 40 includes a conductor layer and an insulation layer. The conductor layer includes a plurality of conductors 41 spaced apart along the axial direction X. The insulation layer is disposed on one side of the conductor layer in the radial direction. A plurality of basic insulation layers 42 are disposed near each of the conductors 41 to electrically insulate one side of the conductors 41 in the radial direction. A plurality of reinforcing insulation layers 43 are disposed away from each of the conductors 41 relative to the basic insulation layers 42 to electrically insulate one side of the conductors 41 in the radial direction. A supporting insulation layer 44 is disposed away from the conductors 41 relative to the reinforcing insulation layers 43 to electrically insulate one side of the conductors 41 in the radial direction. The axial height of the reinforcing insulation layers 43 is greater than the axial height of the basic insulation layers 42. That is, the basic insulation layers 42, reinforcing insulation layers 43, and conductors 41 are arranged in a one-to-one relationship, while the supporting insulation layers 44 and conductors 41 are arranged in a one-to-many relationship. The basic insulation layers 42 can serve the basic function of electrically insulating the conductors 41, for example, by means of a finite-sized material adhered to or surrounding the conductors 41, such as a covering layer on the outside of the conductors 41. The axial height of the reinforcing insulation layer 43 is greater than that of the base insulation layer 42, thus further enhancing the electrical insulation of the conductor 41. Simultaneously, it allows the base insulation layer 42 to maintain a smaller shape factor, reducing its material cost, weight, and loss parameters. The supporting insulation layer 44 serves to support the conductor 41, the base insulation layer 42, and the reinforcing insulation layer 43, while also further enhancing the electrical insulation of the conductor 41. The supporting insulation layer 44 will be described in more detail below.

[0041] Although Figure 2 The conductor layer and insulation layer in the high-voltage coil assembly 40 shown appear to be separate components, but the conductor layer and insulation layer of the high-voltage coil assembly 30 are formed into an integral structure by epoxy resin casting. Therefore, the high-voltage coil assembly 40 also includes an epoxy resin component 45, wherein the epoxy resin component, conductor layer, and insulation layer form an integral structure. For example, for Figure 1 In the dry-type transformer shown, the high-voltage coil assembly 30 can be cast into two coils and then assembled onto the upper clamp 21 and the lower clamp 22. Thus, the internal insulation system of the high-voltage coil assembly 40 includes multiple insulating layers integrally formed with the epoxy resin components, thereby enhancing insulation performance and ensuring sufficient mechanical properties and interlayer bonding strength for each insulating layer. This provides better insulation to meet the insulation requirements of a 72.5kV voltage level, while further reducing the cost, weight, and loss parameters of the insulation materials.

[0042] It should be pointed out that, Figure 2The diagram only shows one side of the conductor 41 of the high-voltage coil assembly 40 (e.g., the side facing the low-voltage coil assembly 30) with the various insulating layers described above. In this case, when the conductor layer and the insulating layers are wound together into a coil, the insulating layers are evenly distributed on both sides of the conductor layer, thus providing internal insulation for the high-voltage coil assembly 40. However, the invention is not limited to this; the various insulating layers described above can also be provided on the opposite sides of the conductor 41, thereby further improving the insulation effect. It should be noted that the length and height of each insulating layer can be greater than the length and height of the conductor 41, respectively, so that more comprehensive insulation can be provided to the conductors of the high-voltage coil assembly 40 (especially the innermost or outermost conductors) during winding.

[0043] like Figure 2 As shown, the supporting insulating layer 44 can be a multi-layer structure (e.g., Figure 2 The diagram shows three layers, wherein the multilayer structure may include a mechanical support layer (not shown), such as a fiberglass layer, to provide mechanical support while improving insulation. Additionally, a portion of the epoxy resin component 45 is located between adjacent layers in the multilayer structure to connect the layers supporting the insulation layer 44 together and can be integrally formed with other portions of the epoxy resin component 45, thereby further improving insulation and structural strength.

[0044] According to one embodiment of the present invention, the base insulation layer 42 and the reinforcing insulation layer 43 can be made of any one selected from the group consisting of polyethylene terephthalate (PET), polyester film, polyester fiber nonwoven flexible composite foil (Dacron Mylar Dacron, DMD), glass fiber prepreg, and epoxy resin. The supporting insulation layer 44 can be made of any one or more selected from the group consisting of PET, DMD, glass fiber prepreg, and epoxy resin. The base insulation layer 42, the reinforcing insulation layer 43, and the supporting insulation layer 44 can be made of the same or different materials depending on the insulation level, production process, etc. Preferably, the base insulation layer 42, the reinforcing insulation layer 43, and the supporting insulation layer 44 can be made of different materials. In this case, by using multiple insulating materials, the characteristics of each insulating material can be fully utilized, and the insulation performance can be further enhanced in an optimized combination.

[0045] Continue to refer to Figure 1According to one embodiment of the present invention, to further improve the insulation effect between the low-voltage coil assembly 30 and the high-voltage coil assembly 40, a plurality of insulating cylinders 50 may be provided between the low-voltage coil assembly 20 and the high-voltage coil assembly 30, and adjacent insulating cylinders 50 are spaced apart from each other by a certain gap. The insulating cylinders 50 may be made of any material selected from the group consisting of PET, DMD, glass fiber prepreg, and epoxy resin. This creates a multi-gap insulation distribution between the low-voltage coil assembly 30 and the high-voltage coil assembly 40, which can further improve the breakdown strength of the air or insulation layer.

[0046] It should be noted that the base insulation layer 42, the reinforcing insulation layer 43, the supporting insulation layer 44, and the insulating cylinder 50 are not limited to being made of the materials described above, but can be made of any suitable material known in the art.

[0047] like Figure 1 As shown, the dry-type transformer 100 also includes an output terminal and a voltage regulating tap 61, for example, the output terminal and voltage regulating tap of the high-voltage coil assembly 40. Existing output terminals and voltage regulating taps 61 are typically exposed, thus potentially leading to air breakdown. The output terminals and voltage regulating taps 61 of the high-voltage coil assembly 40 of the present invention can be externally covered with an insulating protective element 62, which can further improve the insulation effect and reduce the air insulation distance. It should be noted that the present invention is not limited to providing an insulating protective element externally to the output terminals and voltage regulating taps of the high-voltage coil assembly 40, but rather the insulating protective element 62 can be provided on any energized structure of the dry-type transformer 100.

[0048] in addition, Figure 1 The dry-type transformer 100 also includes an upper clamp 21 and a lower clamp 22, with the core 10, low-voltage coil assembly 30, and high-voltage coil assembly 40 assembled between the upper clamp 21 and the lower clamp 22, for example, via spacers. The upper clamp 21 and lower clamp 22, as structural components of the dry-type transformer 100, may also generate an electric field during operation. In existing structural components, the ends and bends are typically roughly sharp-angled, which can easily lead to current concentration and point discharge. According to an embodiment of the invention, the upper clamp 21 and lower clamp 22 include rounded ends 23 and bends 24 forming an arc shape. This allows for a streamlined design with blunted edges, optimizing the electric field distribution and reducing the degree of current concentration and the risk of breakdown.

[0049] To further improve insulation performance, the dry-type transformer 100 also includes insulation spacers. Figure 1(Not shown in the image), such as insulating pads or insulating rubber sheets, the insulating spacers are located between the low-voltage coil assembly 20 and the upper clamp 21 and lower clamp 22, and between the high-voltage coil assembly 30 and the upper clamp 21 and lower clamp 22.

[0050] Compared with existing dry-type transformers, the high-voltage coil assembly 40 of the present invention may include an internal insulation design with multiple layers of insulating materials, an insulation design with multiple gaps between the high-voltage coil assembly 40 and the low-voltage coil assembly 30, a fully insulated external energized structure, a passivation design for the shape of structural components, and an insulation barrier design between the coil assembly and the structural components. Therefore, it can meet the insulation requirements of dry-type transformer products with a voltage level of 72.5kV, providing more reliable options for the power market, and optimizing the structural design of dry-type transformers.

[0051] In summary, the present invention provides a dry-type transformer 100 with a voltage rating of 72.5kV, comprising a high-voltage coil assembly 40, which includes: a conductor layer and an insulation layer; the conductor layer comprising a plurality of conductors 41 spaced apart along the axial direction of the iron core; the insulation layer being disposed on one side of the conductor layer along the radial direction of the iron core, and comprising a plurality of basic insulation layers 42 disposed close to each of the plurality of conductors and electrically insulating one side of the plurality of conductors in the radial direction; a plurality of reinforcing insulation layers 43 disposed away from the basic insulation layers and electrically insulating one side of the plurality of conductors in the radial direction, the axial height of the reinforcing insulation layers being greater than the axial height of the basic insulation layers; a supporting insulation layer 44 disposed away from the plurality of reinforcing insulation layers and electrically insulating one side of the plurality of conductors in the radial direction; and an epoxy resin component 45, which forms an integral structure with the conductor layer and the insulation layer. The dry-type transformer with a voltage rating of 72.5kV of the present invention meets the insulation requirements.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dry-type transformer (100) with a voltage rating of 72.5kV, comprising: Iron core (10), the iron core (10) having an axial direction (X) and a radial direction; A low-voltage coil assembly (30) is coaxially arranged around the iron core (10); and A high-voltage coil assembly (40) is arranged coaxially around the low-voltage coil assembly (30); The high-voltage coil assembly (40) is characterized in that it includes a conductor layer and an insulating layer, the conductor layer comprising a plurality of conductors (41) spaced apart along the axial direction (X), and the insulating layer disposed on one side of the conductor layer along the radial direction, wherein the insulating layer comprises: A plurality of base insulating layers (42) disposed close to each of the plurality of conductors (41) and electrically insulating one side of the plurality of conductors (41) along the radial direction; A plurality of reinforcing insulating layers (43) disposed relative to the base insulating layer (42) away from each of the plurality of conductors (41) and electrically insulating one side of the plurality of conductors (41) along the radial direction, wherein the axial height of the reinforcing insulating layer (43) is greater than the axial height of the base insulating layer (42); and A supporting insulating layer (44) disposed away from the plurality of conductors (41) relative to the plurality of reinforcing insulating layers (43) and electrically insulating one side of the plurality of conductors (41) along the radial direction; The high-voltage coil assembly (40) further includes an epoxy resin component (45), and the epoxy resin component, the conductor layer and the insulating layer form an integrated structure.

2. The dry-type transformer (100) with a voltage level of 72.5kV according to claim 1, characterized in that, The supporting insulating layer (44) has a multi-layer structure, which includes a mechanical support layer.

3. The dry-type transformer (100) with a voltage level of 72.5kV according to claim 2, characterized in that, A portion of the epoxy resin component (45) is located between two adjacent layers in the multilayer structure.

4. The dry-type transformer (100) with a voltage level of 72.5kV according to claim 1, characterized in that, Multiple insulating cylinders (50) are provided between the low-voltage coil assembly (30) and the high-voltage coil assembly (40), and adjacent insulating cylinders (50) are spaced apart by a certain gap.

5. The dry-type transformer (100) with a voltage level of 72.5kV according to claim 1, characterized in that, The dry-type transformer (100) also includes an output terminal and a voltage regulating tap terminal (61), and the output terminal and the voltage regulating tap terminal (61) are covered with an insulating protective component (62).

6. The dry-type transformer (100) with a voltage level of 72.5kV according to claim 1, characterized in that, The dry-type transformer (100) further includes an upper clamp (21) and a lower clamp (22), wherein the iron core (10), the low-voltage coil assembly (30) and the high-voltage coil assembly (40) are assembled between the upper clamp (21) and the lower clamp (22), wherein the upper clamp (21) and the lower clamp (22) include rounded ends (23), and the upper clamp (21) and the lower clamp (22) include curved portions (24) forming an arc shape.

7. The dry-type transformer (100) with a voltage level of 72.5kV according to claim 6, characterized in that, The dry-type transformer (100) further includes an insulating barrier located between the low-voltage coil assembly (30) and the upper clamp (21), between the low-voltage coil assembly (30) and the lower clamp (22), between the high-voltage coil assembly (40) and the upper clamp (21), and between the high-voltage coil assembly (40) and the lower clamp (22).

8. The dry-type transformer (100) with a voltage rating of 72.5kV according to claim 4, characterized in that, The base insulation layer (42), the reinforcing insulation layer (43), and the insulating cylinder (50) are made of any one selected from the group consisting of polyethylene terephthalate, polyester film, polyester fiber nonwoven flexible composite foil, glass fiber prepreg, and epoxy resin, and the supporting insulation layer (44) is made of any one or more selected from the group consisting of polyethylene terephthalate, polyester film, polyester fiber nonwoven flexible composite foil, glass fiber prepreg, and epoxy resin.

9. The dry-type transformer (100) with a voltage rating of 72.5kV according to claim 8, characterized in that, The base insulation layer (42), the reinforcing insulation layer (43), and the supporting insulation layer (44) are made of different materials.

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