A multi-winding dry-type traction transformer

Abstract

This invention discloses a multi-winding dry-type traction transformer, relating to the field of transformer technology. It includes multiple iron cores, with yokes fixedly connected to the top and bottom of each core. Through a heat dissipation mechanism, a first thermally conductive silicone pad, and a second thermally conductive silicone pad, the heat generated by the outer and inner windings is rapidly conducted to the heat dissipation cylinder via the first and second thermally conductive silicone pads. The heat is then conducted to the outer air duct and the first and second inner air ducts. Since the total number of the first and second inner air ducts is greater than the number of outer air ducts, the heat exchange area of ​​the inner cylinder is expanded by setting multiple first and second inner air ducts, thereby improving the heat dissipation efficiency of the inner windings. This allows for more significant heat dissipation of the inner windings under essentially the same cooling intensity applied to both the inner and outer windings, resulting in a greater heat dissipation effect on the inner windings than on the outer windings, thus achieving asymmetrical heat dissipation between the inner and outer windings.

Description

Technical Field

[0001] This invention relates to the field of transformer technology, and more particularly to a multi-winding dry-type traction transformer. Background Technology

[0002] Dry-type transformers are a type of power transformer. They are characterized by not being immersed in insulating oil, but rather relying on air convection or forced air cooling for cooling. They have advantages such as simple structure, convenient maintenance, fire safety, energy saving and environmental protection. Therefore, they are widely used in some places with high environmental safety requirements, such as large buildings, hospitals and factories.

[0003] Currently, dry-type transformers generally consist of an iron core, inner windings, and outer windings. A common heat dissipation method is to use forced air cooling by symmetrically arranging fans at the bottom on both sides of the windings. At high voltage, airflow circulates within the cavity between the inner and outer windings, carrying away the generated heat. However, this traditional heat dissipation design has drawbacks. Because the inner winding is enclosed by the outer winding, the heat it generates is difficult to dissipate, so its operating temperature is usually much higher than that of the outer winding. Applying essentially the same cooling intensity to both windings, this "one-size-fits-all" approach fails to provide focused and intensified cooling to the high-temperature inner winding, while over-cooling the lower-temperature outer winding, resulting in low heat dissipation efficiency and wasted cooling resources. Summary of the Invention

[0004] The purpose of this invention is to address the problem that the heat generated by the inner winding is difficult to dissipate because it is wrapped by the outer winding, resulting in an operating temperature that is usually much higher than that of the outer winding. Applying essentially the same cooling intensity to both the inner and outer windings is not a way to effectively cool the high-temperature inner winding, while overcooling the lower-temperature outer winding is wasteful and inefficient. Therefore, this invention proposes a multi-winding dry-type traction transformer.

[0005] To achieve the above objectives, the present invention employs the following technology: a multi-winding dry-type traction transformer comprising multiple iron cores, wherein yokes are fixedly connected to the top and bottom of each iron core, and upper and lower support frames are respectively provided on the two yokes for clamping and fixing them; an inner winding and an outer winding are sequentially sleeved on the outer side of each iron core from the inside out, forming an annular cavity between the inner and outer windings; a heat dissipation mechanism is provided inside the annular cavity; and a strong cooling mechanism is provided at the bottom of the inner and outer windings. The heat dissipation mechanism includes a heat dissipation cylinder disposed inside an annular cavity. Several external air ducts are opened on one side of the interior of the heat dissipation cylinder, and a first internal air duct and a second internal air duct are opened on one side of the interior of the heat dissipation cylinder. An annular groove is opened in the middle of the heat dissipation cylinder, and a heat insulation sleeve is inserted into the interior of the annular groove.

[0006] As a further description of the multi-winding dry traction transformer described above: a filling cavity is provided between the outer and inner sides of the heat dissipation cylinder and the outer and inner windings, and the two filling cavities are respectively filled with a first thermally conductive silicone pad and a second thermally conductive silicone pad.

[0007] As a further description of a multi-winding dry traction transformer of the above technology: the outer air duct, the first inner air duct, and the second inner air duct are ellipses with the same center but different sizes, and the size of the outer air duct is larger than that of the first inner air duct and the second inner air duct.

[0008] As a further description of a multi-winding dry traction transformer of the above technology: the first inner air duct and the second inner air duct are of equal size, and the first inner air duct and the second inner air duct are arranged alternately at equal intervals.

[0009] As a further description of the multi-winding dry traction transformer described above: the first thermally conductive silicone pad and the second thermally conductive silicone pad are installed from the inside out with the heat dissipation cylinder as the center, and the outer wall and inner wall of the first thermally conductive silicone pad and the second thermally conductive silicone pad are in close contact with the two sides of the inner wall of the two filling cavities, respectively.

[0010] As a further description of the multi-winding dry traction transformer described above: the strong cooling mechanism includes a horizontal member fixedly connected to the lower support frame, a plurality of powerful fans are provided on the top of the horizontal member, a blower is fixedly connected to the air outlet of the powerful fan, a cavity box is fixedly connected to one side of the blower, the cavity box is located at the bottom of the inner winding and the outer winding, a central cylinder is fixedly connected to the middle of the cavity box, and a plurality of first air outlets and second air outlets are arrayed on the upper surface of the cavity box.

[0011] As a further description of the multi-winding dry traction transformer described above: the inner wall diameter of the central cylinder is larger than the outer wall diameter of the iron core; the number of the first air inlets and the external air ducts are equal and they are aligned and connected; the number of the second air inlets and the first and second internal air ducts are equal and they are aligned and connected.

[0012] As a further description of the multi-winding dry traction transformer described above: both sides of the upper surface of the cavity box are fixedly connected with positioning plates for limiting and fixing the outer windings.

[0013] As a further description of the multi-winding dry traction transformer described above: a first row of heat shells is provided at the top of the first inner air duct and the second inner air duct, and a second row of heat shells is provided at the top of the outer air duct.

[0014] In summary, due to the adoption of the above-mentioned technology in a multi-winding dry-type traction transformer, the beneficial effects of this invention are: Through the heat dissipation mechanism, the first thermally conductive silicone pad, and the second thermally conductive silicone pad, the heat generated by the outer and inner windings is quickly conducted to the heat dissipation cylinder via the first and second thermally conductive silicone pads during use. Then, the heat is conducted from the outer and inner walls of the heat dissipation cylinder to the outer air duct and the first and second inner air ducts. Since the total number of the first and second inner air ducts is greater than the number of outer air ducts, the heat exchange area of ​​the inner cylinder is expanded by setting multiple first and second inner air ducts, thereby improving the heat dissipation efficiency of the inner windings and ensuring that the heat applied to the inner and outer windings is essentially the same. Under the cooling intensity, the heat dissipation of the inner winding is enhanced, making the heat dissipation of the inner winding exceed that of the outer winding, thereby avoiding the waste of cooling resources and achieving asymmetrical heat dissipation between the inner and outer windings. At the same time, through the setting of the annular groove and the heat insulation sleeve, the annular groove divides the heat dissipation cylinder into an inner cylinder and an outer cylinder. Together with the heat insulation sleeve, the inner winding and the outer winding are separated for heat dissipation, avoiding heat accumulation and effectively blocking the harmful heat flow path from the inner winding to the outer winding. This prevents the low-temperature side from abnormally rising due to thermal interference, causing temperature runaway, and improves the operational reliability and stability of the entire device. Attached Figure Description

[0015] Figure 1 An overall perspective view provided according to an embodiment of the present invention is shown; Figure 2 An overall side perspective view provided according to an embodiment of the present invention is shown; Figure 3 A partial cross-sectional structural diagram provided according to an embodiment of the present invention is shown; Figure 4 A structural diagram of a forced cooling mechanism provided according to an embodiment of the present invention is shown; Figure 5 The diagram shows the inner and outer winding structures according to an embodiment of the present invention; Figure 6 A cross-sectional view of the heat dissipation mechanism provided according to an embodiment of the present invention is shown; Figure 7 A cross-sectional view of the heat dissipation cylinder provided according to an embodiment of the present invention is shown; Figure 8 A bottom structural diagram of a heat dissipation cylinder provided according to an embodiment of the present invention is shown; Figure 9 The present invention provides an embodiment of the invention. Figure 6 Enlarged view of point A in the middle.

[0016] Legend: 1. Iron core; 2. Iron yoke; 3. Upper support frame; 4. Lower support frame; 5. Inner winding; 6. Outer winding; 7. Annular cavity; 8. Heat dissipation mechanism; 801. Heat dissipation cylinder; 802. Outer air duct; 803. First inner air duct; 804. Second inner air duct; 805. Heat insulation sleeve; 9. Strong cooling mechanism; 901. Horizontal component; 902. Powerful fan; 903. Air blower; 904. Cavity box; 905. Central cylinder; 906. First air outlet; 907. Second air outlet; 10. Filling cavity; 101. First thermally conductive silicone pad; 102. Second thermally conductive silicone pad; 11. Positioning plate; 12. First row of heat shells; 13. Second row of heat shells. Detailed Implementation

[0017] The following will describe, with reference to the accompanying drawings of the embodiments of the present invention, a multi-winding dry-type traction transformer of the present invention clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Reference Figures 1-9 This embodiment provides a multi-winding dry-type traction transformer, including multiple iron cores 1. The top and bottom of the iron cores 1 are respectively fixedly connected to iron yokes 2. The two iron yokes 2 are respectively provided with an upper support frame 3 and a lower support frame 4 for clamping and fixing them. An inner winding 5 and an outer winding 6 are sequentially sleeved on the outer side of the iron cores 1 from the inside to the outside. An annular cavity 7 is formed between the inner winding 5 and the outer winding 6. A heat dissipation mechanism 8 is provided inside the annular cavity 7. A strong cooling mechanism 9 is provided at the bottom of the inner winding 5 and the outer winding 6. The forced cooling mechanism 9 includes a horizontal component 901 fixedly connected to the lower support frame 4. Multiple powerful fans 902 are mounted on the top of the horizontal component 901. Air outlets of the powerful fans 902 are fixedly connected to air blowers 903. A cavity box 904 is fixedly connected to one side of the air blower 903. Positioning plates 11 for limiting and fixing the outer winding 6 are fixedly connected to both sides of the upper surface of the cavity box 904. The cavity box 904 is located at the bottom of the inner winding 5 and the outer winding 6. A central cylinder 905 is fixedly connected to the middle of the cavity box 904. The upper surface of the cavity box 904... The array has several first air inlets 906 and second air inlets 907. The inner winding 5 is sleeved on the top of the central cylinder 905. The central cylinder 905 positions the inner winding 5. At the same time, the outer winding 6 is sleeved on the outside of the inner winding 5. The outer side of the outer winding 6 contacts the inner wall of the positioning plate 11. The positioning plate 11 positions the outer winding 6. Through the cooperation between the central cylinder 905 and the positioning plate 11, the distance between the outer circle of the inner winding 5 and the inner circle of the outer winding 6 is equidistant, so that the outer circle of the inner winding 5 and the outer winding 6 can be accurately installed.

[0019] When the powerful fan 902 is started, it blows out a strong airflow through the air outlet. The strong airflow is blown into the cavity box 904 through the air blower 903. The cavity box 904 is located at the bottom of the inner winding 5 and the outer winding 6. Then, the positioning plate 11 enables the first air outlet 906 and the second air outlet 907 to be located inside the annular cavity 7. Therefore, when the strong airflow is blown into the cavity box 904 through the air blower 903, it is blown out through the first air outlet 906 and the second air outlet 907. The strong airflow blows towards the heat dissipation mechanism 8 inside the annular cavity 7, which plays a role in heat dissipation.

[0020] Specifically, such as Figure 7 and Figure 8 As shown, the heat dissipation mechanism 8 includes a heat dissipation cylinder 801 disposed inside the annular cavity 7. Several external air ducts 802 are formed on one side of the interior of the heat dissipation cylinder 801, and a first internal air duct 803 and a second internal air duct 804 are formed on the other side. An annular groove is formed in the middle of the heat dissipation cylinder 801, and a heat insulation sleeve 805 is inserted into the annular groove. The annular groove divides the heat dissipation cylinder 801 into an inner cylinder and an outer cylinder. With the heat insulation sleeve 805, heat can be conducted and dissipated from the inner winding 5 and the outer winding 6 respectively through the inner and outer cylinders. Since the inner winding 5... Both the inner winding 5 and the outer winding 6 generate heat. The heat from the inner winding 5 and the outer winding 6 will diffuse to both sides, so the heat will be conducted into the annular cavity 7, forming heat accumulation, which can easily cause temperature runaway. Therefore, by setting up the heat insulation sleeve 805, the heat dissipation cylinder 801, and various air ducts on the heat dissipation cylinder 801, the inner winding 5 and the outer winding 6 can be separated for heat dissipation, avoiding heat accumulation, effectively blocking the harmful heat flow path from the inner winding 5 (high temperature side) to the outer winding 6 (low temperature side), preventing the low temperature side from abnormally rising due to thermal interference, causing temperature runaway, and improving the operational reliability and stability of the entire device. Then, when the inner winding 5 and the outer winding 6 generate heat during operation, the heat generated by the inner winding 5 and the outer winding 6 is conducted to the heat dissipation cylinder 801. Therefore, when the strong air blown out blows towards the heat dissipation mechanism 8 inside the annular cavity 7, the strong air blows into the outer air duct 802 and the first inner air duct 803 and the second inner air duct 804, and then flows vertically upwards and out along the outer air duct 802 and the first inner air duct 803 and the second inner air duct 804. The outer air duct 802 and the first inner air duct 803 and the second inner air duct 804 are vertical channels, so when the air blows in, a "chimney effect" can be formed, and the heat flow naturally flows upwards, in the same direction as the cooling airflow. At the same time, with the air blown out by the strong fan 902, when the air passes through the outer air duct 802 and the first inner air duct 803 and the second inner air duct 804, it can accelerate the carrying out of the heat conducted to the heat dissipation cylinder 801, thereby simultaneously dissipating heat from the inner winding 5 and the outer winding 6 and improving the heat dissipation efficiency. The outer air duct 802, the first inner air duct 803, and the second inner air duct 804 are ellipses with the same center but different sizes. The outer air duct 802 is larger than the first inner air duct 803 and the second inner air duct 804, while the first inner air duct 803 and the second inner air duct 804 are equal in size. The first inner air duct 803 and the second inner air duct 804 are arranged equidistantly and alternately. Since the inner winding 5 is located inside the outer winding 6 and is wrapped by the outer winding 6, while the outer side of the outer winding 6 is in direct contact with the outside air, the temperature of the inner winding 5 is higher than that of the outer winding 6, thus forming an asymmetrical heat source. In the prior art, when dissipating heat from the inner winding 5 and the outer winding 6, fans are usually arranged on both sides of the bottom of the inner winding 5 and the outer winding 6 for symmetrical heat dissipation design. This heat dissipation method cannot address the different heat dissipation needs of the inner winding 5 and the outer winding 6. The inner winding 5 needs to... To achieve stronger heat dissipation, the outer winding 6 requires less heat dissipation than the inner winding 5. This heat dissipation method has low efficiency. The first inner air duct 803 and the second inner air duct 804 are both located on the inner cylinder, while the outer air duct 802 is located on the outer cylinder. The total number of the first inner air duct 803 and the second inner air duct 804 is greater than the number of the outer air duct 802. By setting multiple first inner air ducts 803 and the second inner air ducts 804, the heat exchange area of ​​the inner cylinder is expanded, thereby improving the heat dissipation efficiency of the inner winding 5. Under the same cooling intensity applied to the inner and outer windings, the heat dissipation of the inner winding 5 (high temperature side) is amplified, making the heat dissipation force of the inner winding 5 (high temperature side) exceed that of the outer winding 6 (low temperature side). This avoids the waste of cooling resources and achieves asymmetrical heat dissipation for the inner winding 5 and the outer winding 6. Meanwhile, the outer air duct 802 is larger than the first inner air duct 803 and the second inner air duct 804. The first inner air duct 803 and the second inner air duct 804 are equal in size. Therefore, when a strong wind blows into the outer air duct 802, the first inner air duct 803 and the second inner air duct 804, the airflow velocity inside the first inner air duct 803 and the second inner air duct 804 is greater than that inside the outer air duct 802 because the outer air duct 802 is larger than the first inner air duct 803 and the second inner air duct 804. This improves the heat dissipation effect of the first inner air duct 803 and the second inner air duct 804 on the inner winding 5.

[0021] Specifically, such as Figure 2 , Figure 3 and Figure 4 As shown, the inner diameter of the central cylinder 905 is larger than the outer diameter of the iron core 1. The number of the first air outlet 906 and the outer air duct 802 are equal and they are aligned and connected. The number of the second air outlet 907, the first inner air duct 803, and the second inner air duct 804 are equal and they are aligned and connected.

[0022] Strong winds are blown out from the first air outlet 906 and the second air outlet 907. The first air outlet 906 and the second air outlet 907 are aligned with the air ducts one by one, so that the airflow is accurately and directly blown into the outer air duct 802, the first inner air duct 803 and the second inner air duct 804, which greatly reduces the waste of wind power resources.

[0023] Specifically, such as Figure 8 and Figure 9 As shown, a filling cavity 10 is provided between the outer side and the inner side of the heat dissipation cylinder 801 and the outer winding 6 and the inner winding 5, respectively. The two filling cavities 10 are filled with a first thermally conductive silicone pad 101 and a second thermally conductive silicone pad 102. The first thermally conductive silicone pad 101 and the second thermally conductive silicone pad 102 are installed from the inside out with the heat dissipation cylinder 801 as the center. The outer and inner walls of the first thermally conductive silicone pad 101 and the second thermally conductive silicone pad 102 are in close contact with the two sides of the inner wall of the two filling cavities 10, respectively.

[0024] The first thermally conductive silicone pad 101 and the second thermally conductive silicone pad 102 have good thermal conductivity. The heat generated by the outer winding 6 and the inner winding 5 is quickly conducted to the heat dissipation cylinder 801 through the first thermally conductive silicone pad 101 and the second thermally conductive silicone pad 102, thereby accelerating the heat conduction efficiency of the outer winding 6 and the inner winding 5.

[0025] The top of the first inner air duct 803 and the second inner air duct 804 is provided with a first row of heat shells 12, and the top of the outer air duct 802 is provided with a second row of heat shells 13.

[0026] The first row of heat shells 12 and the second row of heat shells 13 both have heat dissipation vents on their circumferential surfaces. The height of the first row of heat shells 12 is greater than that of the second row of heat shells 13. The heat dissipation vents on the first row of heat shells 12 are located above the heat dissipation vents on the second row of heat shells 13. When the heat emitted by the inner winding 5 and the outer winding 6 is discharged from the first inner air duct 803 and the second inner air duct 804 and the outer air duct 802 respectively into the first row of heat shells 12 and the second row of heat shells 13, it is then discharged from the heat dissipation vents. The first row of heat shells 12 and the second row of heat shells 13 shield the first inner air duct 803 and the second inner air duct 804 and the outer air duct 802, reducing the entry of dust.

[0027] Working principle: When the outer winding 6 and inner winding 5 generate heat during operation, the heat generated by the outer winding 6 and inner winding 5 is quickly conducted to the heat dissipation cylinder 801 through the first thermally conductive silicone pad 101 and the second thermally conductive silicone pad 102. After the heat is conducted to the heat dissipation cylinder 801, the annular groove divides the heat dissipation cylinder 801 into an inner cylinder and an outer cylinder. Then, the inner cylinder and the outer cylinder conduct heat dissipation for the inner winding 5 and the outer winding 6 respectively. Furthermore, through the heat insulation sleeve 805, the heat dissipation cylinder 801, and the various air ducts opened on the heat dissipation cylinder 801, the inner winding 5 and the outer winding 6 can be separated for heat dissipation, avoiding heat accumulation and effectively blocking the harmful heat flow path from the inner winding 5 (high temperature side) to the outer winding 6 (low temperature side). This prevents the low temperature side from abnormally rising due to thermal interference, causing temperature runaway, and improves the operational reliability and stability of the entire device.

[0028] When heat is conducted to the heat dissipation cylinder 801, and then from the heat dissipation cylinder 801 to the outer air duct 802 and the first inner air duct 803 and the second inner air duct 804, the powerful fan 902 starts, and the powerful fan 902 blows out a strong airflow. The strong airflow is blown into the cavity box 904 through the air blower 903. The cavity box 904 is located at the bottom of the inner winding 5 and the outer winding 6. Then, the positioning plate 11 can make the first air outlet 906 and the second air outlet 907 located inside the annular cavity 7. Therefore, when the strong airflow is blown into the cavity box 904 through the air blower 903, it is blown out through the first air outlet 906 and the second air outlet 907. After the strong airflow is blown out from the first air outlet 906 and the second air outlet 907, it is aligned with the air ducts one by one, accurately directing the airflow. The airflow is directly blown into the outer air duct 802, the first inner air duct 803, and the second inner air duct 804. When the strong airflow blows into the outer air duct 802, the first inner air duct 803, and the second inner air duct 804, the strong airflow flows vertically upwards and is discharged. The outer air duct 802, the first inner air duct 803, and the second inner air duct 804 are vertical channels. Therefore, when the airflow blows in, it can form a "chimney effect". The heat flow naturally flows upwards, in the same direction as the cooling airflow. At the same time, in conjunction with the airflow blown out by the powerful fan 902, when the airflow passes through the outer air duct 802, the first inner air duct 803, and the second inner air duct 804, it can accelerate the removal of the heat transferred to the heat dissipation cylinder 801, thereby simultaneously dissipating heat from the inner winding 5 and the outer winding 6, and improving the heat dissipation efficiency.

[0029] Meanwhile, the total number of the first inner air duct 803 and the second inner air duct 804 is greater than the number of the outer air duct 802. By setting multiple first inner air ducts 803 and the second inner air ducts 804, the heat exchange area of ​​the inner cylinder is expanded, thereby improving the heat dissipation efficiency of the inner winding 5. Under the same cooling intensity applied to the inner and outer windings, the heat dissipation of the inner winding 5 (high temperature side) is amplified, making the heat dissipation force of the inner winding 5 (high temperature side) exceed that of the outer winding 6 (low temperature side), avoiding the waste of cooling resources and achieving asymmetrical heat dissipation of the inner winding 5 and the outer winding 6. At the same time, the size of the outer air duct 802 is larger than that of the first inner air duct 803 and the second inner air duct 804, and the airflow velocity inside the first inner air duct 803 and the second inner air duct 804 is greater than that of the outer air duct 802, thereby further improving the heat dissipation effect of the first inner air duct 803 and the second inner air duct 804 on the inner winding 5.

[0030] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technology of the present invention and the inventive concept of the multi-winding dry traction transformer, should be covered within the scope of protection of the present invention.

Claims

1. A multi-winding dry-type traction transformer, comprising multiple iron cores (1), characterized in that, The top and bottom of the iron core (1) are respectively fixedly connected to the iron yoke (2). The two iron yokes (2) are respectively provided with an upper support frame (3) and a lower support frame (4) for clamping and fixing them. The outer side of the iron core (1) is successively sleeved with an inner winding (5) and an outer winding (6) from the inside to the outside. An annular cavity (7) is formed between the inner winding (5) and the outer winding (6). A heat dissipation mechanism (8) is provided inside the annular cavity (7). A strong cooling mechanism (9) is provided at the bottom of the inner winding (5) and the outer winding (6). The heat dissipation mechanism (8) includes a heat dissipation cylinder (801) disposed inside the annular cavity (7). A plurality of external air ducts (802) are provided on one side of the interior of the heat dissipation cylinder (801). A first internal air duct (803) and a second internal air duct (804) are provided on one side of the interior of the heat dissipation cylinder (801). An annular groove is provided in the middle of the heat dissipation cylinder (801), and a heat insulation sleeve (805) is inserted into the interior of the annular groove. The outer and inner sides of the heat dissipation cylinder (801) are provided with filling cavities (10) between the outer winding (6) and the inner winding (5), and the two filling cavities (10) are respectively filled with a first thermally conductive silicone pad (101) and a second thermally conductive silicone pad (102). The strong cooling mechanism (9) includes a horizontal component (901) fixedly connected to the lower support frame (4). The top of the horizontal component (901) is provided with multiple powerful fans (902). The air outlet of the powerful fans (902) is fixedly connected to a blower (903). A cavity box (904) is fixedly connected to one side of the blower (903). The cavity box (904) is located at the bottom of the inner winding (5) and the outer winding (6). A central cylinder (905) is fixedly connected to the middle of the cavity box (904). Several first air outlets (906) and second air outlets (907) are arrayed on the upper surface of the cavity box (904). The inner diameter of the central cylinder (905) is larger than the outer diameter of the iron core (1). The number of the first air outlet (906) and the outer air duct (802) are equal and they are aligned and connected. The number of the second air outlet (907) and the first inner air duct (803) and the second inner air duct (804) are equal and they are aligned and connected.

2. The multi-winding dry-type traction transformer according to claim 1, characterized in that, The outer air duct (802) is an ellipse with the same center as the first inner air duct (803) and the second inner air duct (804), but with different sizes. The outer air duct (802) is larger than the first inner air duct (803) and the second inner air duct (804).

3. A multi-winding dry-type traction transformer according to claim 1, characterized in that, The first inner air duct (803) and the second inner air duct (804) are of equal size and are arranged alternately at equal intervals.

4. A multi-winding dry-type traction transformer according to claim 1, characterized in that, The first thermally conductive silicone pad (101) and the second thermally conductive silicone pad (102) are installed from the inside out with the heat dissipation cylinder (801) as the center. The outer and inner walls of the first thermally conductive silicone pad (101) and the second thermally conductive silicone pad (102) are in close contact with the two sides of the inner wall of the two filling cavities (10), respectively.

5. A multi-winding dry-type traction transformer according to claim 1, characterized in that, Both sides of the upper surface of the cavity box (904) are fixedly connected with a locking plate (11) for limiting and fixing the outer winding (6).

6. A multi-winding dry-type traction transformer according to claim 1, characterized in that, The top of the first inner air duct (803) and the second inner air duct (804) is provided with a first row of heat shells (12), and the top of the outer air duct (802) is provided with a second row of heat shells (13).

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