Dry-type transformer

Abstract

The present application provides a dry-type transformer, comprising: a base, iron cores, winding units, and fans. The winding units and the fans are both mounted on the base; each winding unit comprises a high-voltage winding, an insulating cylinder, and a low-voltage winding which are sequentially sleeved from outside to inside; the low-voltage winding comprises a low-voltage winding body and a plurality of support strips, the low-voltage winding body is cylindrical, the support strips are arranged in the low-voltage winding body, and the plurality of support strips are distributed at intervals; and the side walls of the support strips are provided with a plurality of first recesses distributed at intervals in the longitudinal direction of the support strips. The technical problem of failure in dry-type transformers due to insufficient heat dissipation capacity is mitigated.

Description

dry-type transformers

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on October 30, 2023, with application number 202311427705.7 and application name “Dry-type Transformer”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of transformer equipment, and in particular to a dry-type transformer. Background Art

[0003] Dry-type transformers primarily consist of an iron core, low-voltage windings, and high-voltage windings. During operation, dry-type transformers experience losses in the windings and core, generating internal heat. If heat transfer is slow, it accumulates within the transformer. When the accumulated temperature exceeds the insulation's tolerance, the insulation degrades. The operational reliability of dry-type transformers depends largely on their insulation performance, which in turn is closely related to the transformer's ability to generate and dissipate heat. Dry-type transformers are susceptible to failure, either directly or indirectly, due to abnormal temperatures.

[0004] Dry-type transformers primarily rely on natural convection and forced air cooling. Installing a fan at the base of the transformer can improve its heat dissipation capacity. To improve this, dry-type transformers are typically installed in a well-ventilated environment, leveraging the natural wind pressure to enhance ventilation within the transformer chamber. However, dry-type transformers often suffer from insufficient heat dissipation, which often leads to failures.

[0005] Summary of the Invention

[0006] The purpose of this application is to provide a dry-type transformer to alleviate the technical problem of dry-type transformer failure due to insufficient heat dissipation capacity.

[0007] The above-mentioned purpose of this application can be achieved by adopting the following technical solutions:

[0008] The present application provides a dry-type transformer, comprising: a base, an iron core, a winding unit and a fan, wherein the winding unit and the fan are both installed on the base, and the winding unit comprises a high-voltage winding, an insulating cylinder and a low-voltage winding which are sequentially sleeved from the outside to the inside; the low-voltage winding comprises a low-voltage winding body and a plurality of struts, wherein the low-voltage winding body is cylindrical, the struts are arranged in the low-voltage winding body, and the plurality of struts are distributed at intervals; the side walls of the struts are provided with a plurality of first grooves which are distributed at intervals along the longitudinal direction thereof.

[0009] In a preferred embodiment, the stay includes alternately distributed first supporting portions and second supporting portions, the cross section of the first supporting portion is different from the cross section of the second supporting portion, and the first groove is located outside the first supporting portion.

[0010] In a preferred embodiment, the width of the first supporting portion is smaller than the width of the second supporting portion.

[0011] In a preferred embodiment, the thickness of the first support portion in the inner and outer directions is greater than the thickness of the second support portion in the inner and outer directions.

[0012] In a preferred embodiment, both the upper end and the lower end of the stay serve as the first supporting portion.

[0013] In a preferred embodiment, the cross-sections of the first supporting portion and the second supporting portion are both rectangular.

[0014] In a preferred embodiment, the inner wall of the insulating cylinder is provided with a plurality of protrusions, and / or the outer wall of the insulating cylinder is provided with a plurality of protrusions.

[0015] In a preferred embodiment, at least two of the protrusions are arranged in a group; and the distance between the upper ends of the two protrusions arranged in a group is smaller than the distance between the lower ends.

[0016] In a preferred embodiment, two protrusions arranged in a group constitute a vortex generator, and a plurality of the vortex generators are arranged at intervals in the up-down direction.

[0017] In a preferred embodiment, a guide channel is provided between the upper ends of two of the protrusions arranged in a group, and the guide channels of the plurality of vortex generators arranged at intervals in the up-down direction are aligned.

[0018] In a preferred embodiment, the high-voltage winding is provided with a plurality of heat dissipation channels, and the upper end cross-section of the heat dissipation channel is larger than the lower end cross-section.

[0019] In a preferred embodiment, the heat dissipation air duct includes an upper hole portion and a lower hole portion, and the width of the upper hole portion is greater than the width of the lower hole portion.

[0020] In a preferred embodiment, two fans are provided below one winding unit, and the dry-type transformer includes at least three winding units arranged side by side.

[0021] The features and advantages of this application are:

[0022] The stays support the low-voltage winding body, ensuring support strength. Airflow channels are formed between the stays, and the first grooves on the stays also allow airflow, facilitating airflow within the low-voltage winding body to remove heat. Furthermore, the provision of the first grooves reduces the contact area between the stays and the surface of the low-voltage winding body, thereby increasing the heat dissipation area. The multiple first grooves are spaced apart, disrupting the boundary layer of the airflow, thereby increasing turbulence and thinning the boundary layer. This facilitates the use of the continuous disturbance of the airflow and increased turbulence to enhance heat transfer, improving the heat dissipation capacity of the low-voltage winding. This reduces the overall temperature rise of the low-voltage winding in this dry-type transformer and alleviates the technical problem of dry-type transformer failure due to insufficient heat dissipation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG1 is a top view of a winding unit in a dry-type transformer provided in the present application;

[0024] FIG2 is a front view of a winding unit (omitting the low-voltage winding) in a dry-type transformer provided by the present application;

[0025] FIG3 is a top view of the low-voltage winding in the winding unit shown in FIG1 ;

[0026] FIG4 is a partial cross-sectional view taken along line AA in FIG3 ;

[0027] FIG5 is a schematic diagram of the airflow of the low-voltage winding shown in FIG4 ;

[0028] FIG6 is a partial cross-sectional view taken along line BB in FIG3 ;

[0029] FIG7 is a top view of a support bar in a dry-type transformer provided by the present application;

[0030] FIG8 is a front view of FIG7;

[0031] FIG9 is a left side view of FIG7;

[0032] FIG10 is a partial cross-sectional view of the low-voltage winding, high-voltage winding, and insulating cylinder in the dry-type transformer provided by the present application;

[0033] FIG11 is a front view of an insulating cylinder in a dry-type transformer provided by the present application;

[0034] FIG12 is a front view of the vortex generator in the insulating cylinder shown in FIG11;

[0035] FIG13 is a schematic structural diagram of the raised portion in the insulating cylinder shown in FIG11;

[0036] FIG14 is a left side view of FIG13;

[0037] FIG15 is a top view of the high-voltage winding in the winding unit shown in FIG1 ;

[0038] FIG16 is a vertical partial cross-sectional view of a high-voltage winding in a dry-type transformer provided by the present application;

[0039] FIG17 is a schematic structural diagram of an embodiment of an airway plate for forming heat dissipation airways in the high-voltage winding shown in FIG15 ;

[0040] FIG18 is a schematic structural diagram of another embodiment of an airway plate for forming heat dissipation airways in the high-voltage winding shown in FIG15 ;

[0041] FIG19 is a front view of the dry-type transformer provided by the present application;

[0042] FIG20 is a top view of a winding unit in the dry-type transformer shown in FIG19 ;

[0043] FIG21 is a left side view of FIG19;

[0044] FIG22 is a top view of the support frame in the dry-type transformer shown in FIG19 .

[0045] Explanation of the main component symbols: 10-winding unit; 20-low-voltage winding; 21-low-voltage winding body; 30-support bar; 31-first support part; 32-second support part; 301-first groove; 302-second groove; 331-width direction; 332-inside and outside direction; 40-insulating tube; 41-raised part; 42-guide channel; 43-vortex generator; 50-high-voltage winding; 51-heat dissipation duct; 511-upper hole part; 512-lower hole part; 52-airway plate; 60-support frame; 61-upper pad; 62-lower pad; 71-fan; 72-iron core; 80-seat. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0047] The present application provides a dry-type transformer, as shown in Figures 1-2 and 19-21, including: a base body 80, an iron core 72, a winding unit 10 and a fan 71, the winding unit 10 and the fan 71 are both installed on the base body 80, the winding unit 10 includes a high-voltage winding 50, an insulating tube 40 and a low-voltage winding 20 that are sequentially sleeved from the outside to the inside; the low-voltage winding 20 includes a low-voltage winding body 21 and a plurality of struts 30, as shown in Figures 3-4, the low-voltage winding body 21 is cylindrical, the struts 30 are arranged in the low-voltage winding body 21, and the plurality of struts 30 are distributed at intervals; the side wall of the strut 30 is provided with a plurality of first grooves 301 distributed at intervals along its longitudinal direction.

[0048] The struts 30 support the low-voltage winding body 21, ensuring support strength. Airways are formed between the struts 30, and the first grooves 301 on the struts 30 also allow airflow, facilitating airflow within the low-voltage winding body 21 to remove heat. Furthermore, the provision of the first grooves 301 reduces the contact area between the struts 30 and the surface of the low-voltage winding body 21, thereby increasing the heat dissipation area. The multiple first grooves 301 are spaced apart, disrupting the boundary layer of the airflow, thereby enhancing turbulence and reducing the thickness of the boundary layer. This facilitates utilizing the continuous disturbance of the airflow and increasing turbulence to enhance heat transfer, thereby improving the heat dissipation capacity of the low-voltage winding 20 and reducing the overall temperature rise of the low-voltage winding 20 in the dry-type transformer.

[0049] The low-voltage winding 20 can be a low-voltage foil-wound winding. When the transformer is operating or suddenly short-circuited, the low-voltage foil-wound winding generates electromagnetic forces. These forces can reach hundreds of times greater than those during rated operation, causing the low-voltage winding to deform under pressure. Several support bars are placed in the low-voltage winding airway, providing separation and support.

[0050] In typical dry-type transformers, the bracing structure typically uses rectangular braces, I-shaped braces, and other structures, with several braces evenly distributed within the airway. While this type of brace is simple and easy to form, it comes into direct contact with the surface of the low-voltage winding, resulting in poor heat dissipation at the contact surface. Furthermore, the braces divide the airway into several smaller ducts. Due to structural limitations of the transformer, the fan is typically mounted on either side of the bottom. This forces air from the fan to enter only through a few small ducts near the fan, preventing it from distributing throughout the entire low-voltage winding airway. This significantly reduces heat dissipation from the low-voltage winding.

[0051] Taking into account the structural characteristics of the low-voltage foil-wound winding, in order to enhance the heat dissipation capacity of the low-voltage winding 20, in one embodiment of the present application, the strut 30 includes a first support portion 31 and a second support portion 32 that are alternately distributed. As shown in Figures 4-9, the cross-section of the first support portion 31 is different from the cross-section of the second support portion 32, and the first groove 301 is located on the outside of the first support portion 31. Since the shapes of the first support portion 31 and the second support portion 32 change and the two are alternately distributed, the side wall of the strut 30 is formed into a concave and convex shape, and the concave part of the side wall of the strut 30 constitutes the first groove 301.

[0052] Furthermore, the width of the first support portion 31 is smaller than the width of the second support portion 32. As shown in Figures 3 and 7-8, the low-voltage winding 20 is annular, and its cross-section is oblong. The stays 30 are distributed along the circumference of the low-voltage winding 20 (the circumferential direction is the circumferential direction), and the width direction 331 of the stays 30 corresponds to the circumference of the low-voltage winding 20. That is, the larger the width of the first support portion 31 or the second support portion 32, the larger the size it occupies in the circumferential direction of the low-voltage winding 20. For a stay 30, since the width of the first support portion 31 is smaller than the width of the second support portion 32, a first groove 301 is formed on the outside of the first support portion 31, and the first groove 301 is located between the two second support portions 32.

[0053] As shown in Figures 7 to 9, the thickness of the first support part 31 in the inner and outer directions 332 is greater than the thickness of the second support part 32 in the inner and outer directions 332. The low-voltage winding 20 is annular, and the thickness of the support bar 30 corresponds to the inner and outer directions 332 of the low-voltage winding 20, that is, the larger the size of the first support part 31 or the second support part 32 in the inner and outer directions 332, the greater its thickness. As shown in Figures 6 and 9, since the thickness of the first support part 31 in the inner and outer directions 332 is greater than the thickness of the second support part 32 in the inner and outer directions 332, a second groove 302 is formed on the outside of the second support part 32. The second groove 302 is located between the two first support parts 31. The airflow can flow circumferentially through the second groove 302, thereby promoting airflow between multiple circumferentially distributed airways.

[0054] As shown in Figures 3 to 6, the first groove 301 and the second groove 302 reduce the contact area between the support bar 30 and the surface of the low-voltage winding body 21, thereby increasing the heat dissipation area; the first groove 301 and the second groove 302 destroy the boundary layer of the fluid, thereby enhancing the turbulence and reducing the thickness of the boundary layer, and utilizing the continuous disturbance of the fluid to increase the turbulence to achieve the purpose of enhancing heat transfer; the air passages are connected, and during forced air cooling, although the wind from the fan 71 only enters from one or several air passages close to the fan 71, the airflow can flow circumferentially through the second groove 302, so that the airflow can spread to the air passage of the entire low-voltage winding 20, achieving full coverage of the airflow, and making the heat dissipated evenly throughout the air passage of the low-voltage winding 20, thereby reducing the overall temperature rise of the low-voltage winding 20.

[0055] Furthermore, the upper and lower ends of the support bar 30 are both first support portions 31, as shown in Figures 4-5 and 8-9. Since a first groove 301 is provided on the outer side of the second support portion 32, the spacing between the support bars 30 at the upper and lower ends is larger, which enlarges the air inlet and outlet of the air duct, reduces the inlet resistance of air entering the air duct, enables more airflow to flow into the air duct, and enhances the heat dissipation capacity.

[0056] In one embodiment, the cross-sections of the first support portion 31 and the second support portion 32 are both rectangular, which facilitates utilizing the stays 30 to enhance the heat dissipation within the airway. Preferably, at the same height, the first support portions 31 of the circumferentially distributed stays 30 are aligned with each other, and the second support portions 32 are aligned with each other. This facilitates airflow within the airway and between the airways, ensuring effective heat dissipation.

[0057] In one embodiment, the inner wall of the insulating tube 40 is provided with multiple protrusions 41, and / or the outer wall of the insulating tube 40 is provided with multiple protrusions 41. As shown in Figures 2 and 10, the low-voltage winding 20 is separated from the high-voltage winding 50 by the insulating tube 40, and airflow channels are formed between the low-voltage winding 20 and the insulating tube 40, and between the insulating tube 40 and the high-voltage winding 50. The protrusions 41 can disturb the airflow, which can disrupt and thin the boundary layer, increase the heat transfer coefficient of the local surface, and enhance the heat transfer effect. Preferably, the inner and outer walls of the insulating tube 40 are each provided with multiple protrusions 41.

[0058] The design structure of dry-type transformers is becoming more and more compact. The airway between the low-voltage winding 20 and the high-voltage winding 50 is getting smaller and smaller. The electrical insulation distance between the high-voltage winding 50 and the low-voltage winding 20 is also correspondingly reduced. An insulating tube 40 is added to the airway. The insulating tube 40 is generally made of epoxy board to prevent excessive voltage from breaking through the low-voltage winding 20. At the same time, it can also play a role in separation and heat dissipation.

[0059] Furthermore, at least two protrusions 41 are arranged in a group; the distance between the upper ends of the two protrusions 41 arranged in a group is smaller than the distance between the lower ends. As shown in Figures 11 and 12, the two protrusions 41 arranged in a group form an "eight" shape. When air flows from bottom to top, the two protrusions 41 arranged in a group jointly disturb the airflow, generating wingtip vortices, which helps the airflow remove heat. Preferably, the two protrusions 41 arranged in a group are symmetrically distributed.

[0060] As shown in Figure 11, two raised portions 41 arranged in a group constitute vortex generators 43, and multiple vortex generators 43 are arranged at intervals in the vertical direction. Furthermore, a guide channel 42 is provided between the upper ends of the two raised portions 41 arranged in a group, and the guide channels 42 of the multiple vortex generators 43 arranged at intervals in the vertical direction are aligned. The airflow flows from bottom to top and flows upward through each guide channel 42 and the channel between two adjacent vortex generators 43. The airflow is disturbed by each vortex generator 43. When the airflow passes through the vortex generator 43, wingtip vortices are generated, which destroy and thin the boundary layer, increase the heat transfer coefficient of the local surface, enhance the heat transfer capacity, and efficiently remove heat. The guide channels 42 of the vortex generators 43 in the same row are aligned, so that the guide channels 42 of the vortex generators 43 in the same row are located on the same vertical line, which is conducive to the flow of air to remove heat.

[0061] Preferably, as shown in FIG. 13 and FIG. 14 , the shape of the protrusion 41 is an airfoil shape, and a plurality of protrusions 41 are evenly distributed on the outer wall of the insulating tube 40 in an “eight” shape.

[0062] An insulating cylinder 40 is placed in the large air passage between the low-voltage winding 20 and the high-voltage winding 50. The raised portion 41 on the insulating cylinder 40 can be formed in a variety of ways, such as by machining or directly forming the raised portion 41 in a mold during the injection molding of the insulating cylinder 40. In one embodiment, the raised portion 41 and the insulating cylinder 40 are formed separately and then connected together. A small hole is bored in the insulating cylinder 40, and the machined raised portion 41 is inserted into the insulating cylinder 40, with the hole and raised portion 41 forming an interference fit.

[0063] Furthermore, as shown in FIG2 , the insulating tube 40 is lengthened so that the upper end of the insulating tube 40 exceeds the height of the low-voltage winding 20 and the high-voltage winding 50 , thereby increasing the height difference and utilizing the “chimney effect” to improve ventilation and heat exchange, thereby increasing the air flow in the airway and thus increasing the natural convection heat exchange.

[0064] The high-voltage winding 50 is equipped with multiple heat dissipation air ducts 51. For epoxy resin-cast high-voltage windings 50, several air duct plates 52 are typically inserted into the air ducts of the high-voltage winding 50. These plates are cast along with the high-voltage winding 50 and then removed from the mold after completion, ultimately forming the heat dissipation air ducts 51. The air duct plates 52 are typically rectangular for ease of fabrication and mold removal.

[0065] The applicant discovered that the temperature field during operation of a dry-type transformer is not uniform across the entire transformer. The highest temperature occurs near the upper end of the high-voltage winding 50. This area, known as a weak point in the insulation material, can lead to insufficient heat dissipation and potentially damage the transformer. However, the rectangular air duct, with its straight top and bottom, does not effectively reduce the temperature at the hottest point.

[0066] The applicant has made improvements to the heat dissipation duct 51 .

[0067] In one embodiment, the cross-section of the upper end of the heat dissipation duct 51 is larger than that of the lower end. Considering that the portion near the upper end of the high-voltage winding 50 is the hottest area and a weak point in the insulation material, enlarging the duct opening at the upper end of the heat dissipation duct 51 effectively increases the heat dissipation area at the hottest point, while keeping the middle and lower ends unchanged, without reducing the structural strength of the high-voltage winding 50.

[0068] During the manufacture of the high-voltage winding 50, as shown in Figure 16, airway plates 52 are evenly placed within the epoxy resin-cast high-voltage winding 50's airway. These airway plates 52 are paddle-plate-like structures, wide at the top and narrow at the bottom, with a circular hole at the top. The airway plates 52 are cast along with the high-voltage winding 50. After being removed from the mold through the circular hole at the top of the airway plates 52, heat dissipation airways 51 are formed at the locations where the airway plates 52 are located. The arrows in Figure 16 indicate the direction of airflow. For ease of illustration, some heat dissipation airways 51 in Figure 16 have airway plates 52, while others do not. As shown in Figure 15, multiple heat dissipation airways 51 are distributed in a circular pattern. At the curved areas of the high-voltage winding 50, the heat dissipation airways 51 also have corresponding curved shapes. Figure 17 illustrates an airway plate 52 forming a curved heat dissipation airway 51, and Figure 18 illustrates an airway plate 52 forming a straight heat dissipation airway 51.

[0069] As shown in FIG16 , the heat dissipation duct 51 includes an upper hole portion 511 and a lower hole portion 512, and the width of the upper hole portion 511 is greater than the width of the lower hole portion 512. The high-voltage winding 50 is annular as shown in FIG15 , and the heat dissipation duct 51 is distributed along the circumference of the high-voltage winding 50. The width direction 331 of the heat dissipation duct 51 corresponds to the circumference of the high-voltage winding 50, that is, the larger the width of the upper hole portion 511 or the lower hole portion 512, the larger the size it occupies in the circumference of the high-voltage winding 50. For a heat dissipation duct 51, the width of the upper hole portion 511 is greater than the width of the lower hole portion 512, that is, the upper end of the heat dissipation duct 51 is larger than the lower end. The air duct opening is enlarged at the upper end of the heat dissipation duct 51, which can effectively increase the heat dissipation area of ​​the hottest point. Preferably, the upper hole portion 511 and the lower hole portion 512 transition in an arc shape.

[0070] In one embodiment, as shown in Figures 19-21, two fans 71 are installed below a winding unit 10. The dry-type transformer includes at least three winding units 10 arranged side by side. The airflow provided by the fans 71 flows from bottom to top into the low-voltage winding 20, the high-voltage winding 50, and the passage therebetween, cooling the low-voltage winding 20 and the high-voltage winding 50. Preferably, as shown in Figure 21, the fans 71 are installed on both sides of the bottom of the high-voltage winding 50. The winding unit 10 is sleeved on the outside of the core leg between two cores 72. As shown in Figures 1-2 and 19-22, the winding unit 10 includes a support frame 60. The support frame 60 is mounted on the base 80 to support the winding unit 10. The support frame 60 includes four upper pads 61 and four lower pads 62. The upper pads 61 and the lower pads 62 are each provided with a groove to secure the insulating cylinder 40 and support the winding unit 10.

[0071] The dry-type transformer provided in this application improves the heat dissipation capacity of the dry-type transformer by enhancing heat transfer by changing the internal structure of the dry-type transformer, without changing the original mechanical structural strength and external environmental conditions of the dry-type transformer and without adding other heat dissipation devices. The operating temperature rise of the dry-type transformer is approximately 5-10°C lower than that of an ordinary dry-type transformer, thereby improving the heat dissipation capacity of the epoxy resin dry-type transformer as a whole.

[0072] The above are only a few embodiments of the present application. Those skilled in the art may make various changes or modifications to the embodiments of the present application based on the contents disclosed in the application documents without departing from the spirit and scope of the present application.

Claims

1. A dry-type transformer, characterized in that: include: A base body, an iron core, a winding unit and a fan, wherein the winding unit and the fan are both installed on the base body, and the winding unit comprises a high-voltage winding, an insulating cylinder and a low-voltage winding which are sequentially sleeved from the outside to the inside; The low voltage winding comprises a low voltage winding body and a plurality of stays, the low voltage winding body is cylindrical, the stays are arranged in the low voltage winding body, and the plurality of stays are distributed at intervals; the side wall of the stay is provided with a plurality of first grooves distributed at intervals along the longitudinal direction thereof; The inner wall of the insulating cylinder is provided with a plurality of protrusions, and / or the outer wall of the insulating cylinder is provided with a plurality of protrusions; At least two of the protrusions are arranged in a group; The distance between the upper ends of the two protrusions arranged in a group is smaller than the distance between the lower ends.

2. The dry-type transformer according to claim 1, characterized in that: The stay includes a first support portion and a second support portion that are alternately distributed, a cross section of the first support portion is different from a cross section of the second support portion, and the first groove is located at an outer side of the first support portion.

3. The dry-type transformer according to claim 2, characterized in that: The width of the first supporting portion is smaller than the width of the second supporting portion.

4. The dry-type transformer according to claim 3, characterized in that: The thickness of the first supporting portion in the inner and outer directions is greater than the thickness of the second supporting portion in the inner and outer directions.

5. The dry-type transformer according to claim 3, characterized in that: The upper end and the lower end of the stay are both the first supporting parts.

6. The dry-type transformer according to claim 3, characterized in that: The cross sections of the first supporting portion and the second supporting portion are both rectangular.

7. The dry-type transformer according to claim 1, characterized in that: Two protrusions arranged in a group constitute a vortex generator, and a plurality of the vortex generators are arranged at intervals in the up-down direction.

8. The dry-type transformer according to claim 7, characterized in that: A flow guide channel is provided between the upper ends of the two protrusions arranged in a group, and the flow guide channels of the plurality of vortex generators arranged at intervals in the up-down direction are aligned.

9. The dry-type transformer according to any one of claims 1 to 6, characterized in that: The high voltage winding is provided with a plurality of heat dissipation air channels, and the upper end cross section of the heat dissipation air channel is larger than the lower end cross section.

10. The dry-type transformer according to claim 9, characterized in that: The heat dissipation air channel includes an upper hole portion and a lower hole portion, and a width of the upper hole portion is greater than a width of the lower hole portion.

11. The dry-type transformer according to claim 1, characterized in that: Two fans are arranged below one of the winding units, and the dry-type transformer includes at least three winding units arranged side by side.

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