EP4593044A1

EP4593044A1 - Winding assembly, dry-type transformer and method for manufacturing winding assemblyy

Info

Publication number: EP4593044A1
Application number: EP24169006.4A
Authority: EP
Inventors: Shiguang Li; Zhiqiang Tao; Yandong LV; Lu Liu; Qingjun SUN; Lingxia LIU; Tianbing ZHENG; Liang Song; Yang Wang
Original assignee: Hitachi Energy Ltd
Current assignee: Hitachi Energy Ltd
Priority date: 2024-01-24
Filing date: 2024-04-08
Publication date: 2025-07-30
Also published as: CN120376310A

Abstract

The present application provides a winding assembly, a dry-type transformer and a method for manufacturing a winding assembly, and belongs to the technical field of transformers. The winding assembly comprises: a supporting cylinder, comprising: a cylinder body extending in a first direction, the cylinder body having an outer wall and an inner wall; and a first flange and a second flange, the first flange and the second flange being respectively arranged at a first end and a second end of the cylinder body that are opposite each other in the first direction; a coil, the coil being wound around the outer wall of the cylinder body in the first direction; and an encapsulating insulator, the encapsulating insulator encapsulating the supporting cylinder and the coil, such that the encapsulating insulator is filled between the coil and the outer wall of the cylinder body, between turns of the coil, between the coil and the first flange, between the coil and the second flange, and on an outer surface of the first flange and the inner wall of the cylinder body.

Description

TECHNICAL FIELD

The present application relates to the technical field of transformers, and in particular to a winding assembly, a dry-type transformer and a method for manufacturing a winding assembly.

BACKGROUND

A vacuum casting coil (VCC) is a main product of a current dry-type transformer. In order to insulate a winding assembly in the dry-type transformer, it is usually necessary to encapsulate to insulate the winding assembly. For example, epoxy resin casting is widely used as an insulation method for the dry-type transformer.
However, an encapsulating insulator of the current winding assembly is prone to an insulation failure caused by cracking and a surface creepage failure caused by water absorption in extreme and special environments (for example, high temperature, low temperature, impact, outdoor use environments). Therefore, there is an urgent need for a winding assembly with higher cracking resistance and weather resistance in extreme and special environments.

SUMMARY

The present application provides a winding assembly with higher cracking resistance and weather resistance in extreme and special environments.
In a first aspect of the present application, provided is a winding assembly, comprising: a supporting cylinder, comprising: a cylinder body extending in a first direction, the cylinder body having an outer wall and an inner wall; and a first flange and a second flange, the first flange and the second flange being respectively arranged at a first end and a second end of the cylinder body that are opposite each other in the first direction; a coil, the coil being wound around the outer wall of the cylinder body in the first direction; and an encapsulating insulator, the encapsulating insulator encapsulating the supporting cylinder and the coil, such that the encapsulating insulator is filled between the coil and the outer wall of the cylinder body, between turns of the coil, between the coil and the first flange, between the coil and the second flange, and on an outer surface of the first flange and the inner wall of the cylinder body.
In another aspect of the present application, provided is a dry-type transformer comprising a winding assembly in the above embodiment.
In yet another aspect of the present application, provided is a method for manufacturing a winding assembly in the above embodiment, the method including: mounting a cylinder body of a supporting cylinder on a second flange of the supporting cylinder; sleeving the cylinder body and the second flange that are mounted together on an inner mold; winding a coil around an outer wall of the cylinder body; mounting a first flange of the supporting cylinder on the cylinder body; putting the supporting cylinder wound with the coil into an outer mold, and casting a liquid encapsulating insulation material to form an encapsulating insulator, wherein the encapsulating insulator encapsulates the supporting cylinder and the coil, such that the encapsulating insulator is filled between the coil and the outer wall of the cylinder body, between turns of the coil, between the coil and the first flange, between the coil and the second flange, and on an outer surface of the first flange and an inner wall of the cylinder body; and taking out from the outer mold the winding assembly that has undergone casting and curing, and removing the inner mold.
The above is an overview of the present application, and there may be simplifications, generalizations, and omissions of details, so those skilled in the art should recognize that this section is illustrative only and is not intended to limit the scope of the present application in any way. This Summary section is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present application will be more fully and clearly understood from the following specification and appended claims with reference to the accompanying drawings. It can be understood that these drawings only depict some implementations of the content of the present application, and therefore should not be considered as limiting the scope of the content of the present application. By using the accompanying drawings, the content of the present application will be explained more clearly and in detail.

FIG. 1 schematically shows a schematic structural diagram of a winding assembly according to an embodiment of the present application.
FIG. 2 schematically shows a cross-sectional view of the winding assembly of FIG. 1.
FIG. 3 schematically shows a schematic structural diagram of a supporting cylinder according to an embodiment of the present application.
FIG. 4 schematically shows a schematic structural diagram of a first flange according to an embodiment of the present application.
FIG. 5 schematically shows a schematic structural diagram of a second flange according to an embodiment of the present application.
FIG. 6 schematically shows a schematic structural diagram of a test fixture for simulating the application of a fixed force according to an embodiment of the present application.
FIG. 7 schematically shows a flowchart of a method for manufacturing a winding assembly according to an embodiment of the present application.

DETAILED DESCRIPTION OF EMBODIMENTS

The embodiments of the technical solutions of the present application will be described below in detail with reference to the accompanying drawings. The following embodiments are merely used to explain the technical solutions of the present application more clearly, and therefore they are merely used as examples, without limiting the scope of protection of the present application.
Unless otherwise defined, all technical and scientific terms used herein shall have the same meanings as commonly understood by those skilled in the art to which the present application belongs. The terms used herein are merely for the purpose of describing specific embodiments, and are not intended to limit the present application. The terms "comprise" and "have" and any variations thereof in the description and claims of the present application and the brief description of the drawings are intended to cover non-exclusive inclusion.
In the description of the embodiments of the present application, the technical terms such as "first" and "second" are merely used to distinguish different objects, and should not be construed as indicating or implying the relative importance or implicitly indicating the number, the specific order or the primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the term "plurality of" means two or more, unless explicitly and specifically limited otherwise.
The phrase "embodiments" referred to herein means that the descriptions of specific features, structures, and characteristics in combination with the embodiments are comprised in at least one embodiment of the present application. This term appearing in various parts of the specification not necessarily refers to the same embodiment, or an independent or alternative embodiment that is exclusive to other embodiments. Those skilled in the art understand explicitly or implicitly that the embodiment described herein may be combined with another embodiment.
In the description of the embodiments of the present application, the term "and/or" herein simply represents an association relationship that describes associated objects, and represents that three relationships may exist. For example, A and/or B may represent the following three cases: only A exists, both A and B exist, and only B exists. In addition, the character "/" herein generally indicates an "or" relationship between the associated objects.
In the description of the embodiments of the present application, the term "plurality of" means two or more, similarly, "plurality groups of" means two or more groups, and "plurality pieces of" means two or more pieces.
In the description of the embodiments of the present application, the orientation or positional relationships indicated by the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "anticlockwise", "axial", "radial", "circumferential", etc. are based on the orientation or positional relationships shown in the accompanying drawings and are merely for ease of description of the embodiments of the present application and simplification of the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be construed as limiting the embodiments of the present application.
In the description of the embodiments of the present application, unless expressly stated or limited otherwise, the technical terms such as "mounting", "connecting", "connection" and "fixing" should be interpreted broadly, for example, they may be a fixed or detachable connection, or integration; may be a mechanical connection or an electrical connection; and may be a direct connection or an indirect connection by means of an intermediate medium, or may be internal communication between two elements or interaction between the two elements. For those of ordinary skill in the art, the specific meaning of the terms mentioned above in the embodiments of the present application should be construed according to specific circumstances.
In the description of the embodiments of the present application, a flowchart is used to explain operations performed by a system according to an embodiment of the present disclosure. It should be understood that the preceding or following operations are not necessarily performed accurately in order. Instead, various steps may be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from these processes.
At present, in order to insulate a winding assembly in the dry-type transformer, it is usually necessary to encapsulate to insulate the winding assembly.
In some embodiments, an encapsulating insulator of the current winding assembly is prone to an insulation failure caused by cracking and a surface creepage failure caused by water absorption in extreme and special environments (for example, high temperature, low temperature, impact, outdoor use environments).
In view of the above problems, some embodiments of the present application provide an improved winding assembly, and the cracking resistance and weather resistance of the winding assembly in extreme and special environments are improved by means of the specific encapsulation structure of an encapsulating insulator in the winding assembly.
Exemplary embodiments of the present disclosure are described in detail below with reference to the drawings.
Refer to FIG. 1, and further refer to FIG. 2. FIG. 1 schematically shows a schematic structural diagram of a winding assembly 100 according to an embodiment of the present application. FIG. 2 schematically shows a cross-sectional view of the winding assembly 100 of FIG. 1.
Referring to FIGS. 1 and 2, the winding assembly 100 includes a supporting cylinder 110, a coil 170, and an encapsulating insulator 180. The supporting cylinder 110 includes a cylinder body 120, a first flange 150 and a second flange 160. The cylinder body 120 extends in a first direction X, and the cylinder body 120 has an outer wall 130 and an inner wall 140. The first flange 150 and the second flange 160 are respectively arranged at a first end and a second end of the cylinder body 120 that are opposite each other in the first direction X. The coil 170 is wound around the outer wall 130 of the cylinder body 120 in the first direction X. The encapsulating insulator 180 encapsulates the supporting cylinder 110 and the coil 170, such that the encapsulating insulator 180 is filled between the coil 170 and the outer wall 130 of the cylinder body 120, between turns of the coil 170, between the coil 170 and the first flange 150, between the coil 170 and the second flange 160, and on an outer surface 190 of the first flange 150 and the inner wall 140 of the cylinder body 120.
As shown in the figure, the first direction X in the figure is a length direction of the winding assembly 100.
According to some embodiments of the present application, the coil 170 includes at least one of a disk winding or a drop winding.
As shown in FIG. 2, the coil 170 using the drop winding is wound around the outer wall 130 of the cylinder body 120 of the supporting cylinder 110. Although the coil 170 described in FIG. 2 uses the drop winding, the present disclosure is not limited to this. In some embodiments, the coil 170 may also be in the form of the disk winding.
In the example shown in FIG. 2, the encapsulating insulator 180 is not only filled between the coil 170 and the outer wall 130 of the cylinder body 120, between the turns of the coil 170, between the coil 170 and the first flange 150, between the coil 170 and the second flange 160, but also filled on an outer surface 190 of the first flange 150 and the inner wall 140 of the cylinder body 120. In other words, the encapsulating insulator 180 fills and wraps the entire winding assembly 100 (including an upper end surface of the winding assembly 100 and an inner wall of the supporting cylinder) except for an outer surface of the second flange 160.
By means of the specific encapsulation structure of the encapsulating insulator, the encapsulating insulator 180 fills and wraps almost the entire winding assembly 100, which reduces the possibility that some parts of the winding assembly are prone to an insulation failure caused by cracking and water absorption in extreme and special environments (for example, high temperature, low temperature, impact and outdoor use environments), and improves the cracking resistance and weather resistance of the winding assembly.
According to some embodiments of the present application, the encapsulating insulator 180 is made of an elastomeric insulation material. In some embodiments, the elastomeric insulation material may include a silicone rubber (SiR).
In epoxy resin casting which is widely used as an insulation method for the winding assembly in the dry-type transformer, a long colloid solidification/curing time (for example, 4-8 hours) and a post-curing time (for example, 10 hours) are required in a production line to achieve a better performance of epoxy materials. In addition, some characteristics of the epoxy materials would limit the performance of dry-type transformer applications (for example, extreme environmental tolerance would be limited by the low-temperature crack resistance of the epoxy materials). From the perspective of material substitution, using the silicone rubber can solve or partially solve the limitations faced by the epoxy materials, thus improving the robustness of the dry-type transformer in extreme and special environments and expanding the scope of application thereof.
By configuring the encapsulating insulator 180 to be made of the silicone rubber, shorter curing time (for example, 1-2 hours), higher product robustness for harsh environments (for example, high temperature, low temperature, impact, low noise requirements and outdoor use), non-flammability and low hygroscopicity when the coil is covered may be achieved.
According to some embodiments of the present application, the supporting cylinder 110 is made of a rigid insulation material, that is, the cylinder body 120, the first flange 150 and the second flange 160 are all made of the rigid insulation material. In some embodiments, the rigid insulation material may include an epoxy fiberglass material.
In some embodiments, a primer is applied on a surface of the cylinder body 120. The primer may be used to strengthen a bonding interface between the supporting cylinder 110 and the encapsulating insulator 180, such as the silicone rubber.
Further refer to FIGS. 3 and 4. FIG. 3 schematically shows a schematic structural diagram of a supporting cylinder 110 according to an embodiment of the present application. FIG. 4 schematically shows a schematic structural diagram of a first flange 150 according to an embodiment of the present application. As shown in FIG. 3, before the encapsulating insulator 180 is casted, the first flange 150 and the second flange 160 are detachably sleeved on two ends of the cylinder body 120, and the upper and lower flanges are designed to be assembled respectively. As shown in FIG. 4, the first flange 150 includes a first connection portion 200 and a first edge portion 210. The first connection portion 200 is configured to be inserted into the cylinder body 120, so as to sleeve the cylinder body 120 outside the first connection portion 200. The first edge portion 210 is connected to the first connection portion 200, and the first edge portion 210 extends beyond the outer wall 130 of the cylinder body 120 when the first connection portion 200 is inserted into the cylinder body 120.
In the example shown in FIG. 4, the first flange 150 is designed to have a bent shape, and the first edge portion 210 of the first flange extends beyond the outer wall 130 of the cylinder body 120 when the first connection portion 200 is inserted into the cylinder body 120 (as shown in FIG. 3), such that the whole supporting cylinder 110 can provide support in axial and radial directions.
Continue to refer to FIGS. 3 and 4. According to some embodiments of the present application, at least one notch 220 extending in a circumferential direction of the first flange 150 is provided in the first flange 150. In the example shown in FIG. 4, eight notches 220 are provided in the first flange 150. Although eight notches 220 are shown in FIG. 4, it can be understood that other numbers of notches 220 may be provided, such as five, seven, nine, etc., which is not limited in the present disclosure. In some embodiments, the at least one notch 220 is equidistantly arranged on a periphery of the first flange 150. However, it can be understood that in some other embodiments, the at least one notch 220 may also not be equidistantly arranged on the periphery of the first flange 150.
According to some embodiments of the present application, the notches 220 may extend through the first connection portion 200, and the notches 220 partially extend in the first edge portion 210.
As shown in FIG. 4, the notches 220 extend through the first connection portion 200, such that the first connection portion 200 is divided into several segments by the plurality of notches 220, however, the notches 220 do not extend through the first edge portion 210, but only partially extend on the first edge portion 210.
Such a design of an extension direction of the notch makes it easier for the encapsulating insulator 180 to pass through the notches 220 and reach the inner wall 140 of the cylinder body 120 and the outer surface 190 of the first flange 150 during casting.
Further refer to FIG. 5. FIG. 5 schematically shows a schematic structural diagram of a second flange 160 according to an embodiment of the present application. The second flange 160 includes a second connection portion 230 and a second edge portion 240. The second connection portion 230 is configured to be inserted into the cylinder body 120, so as to sleeve the cylinder body 120 outside the second connection portion 230. The second edge portion 240 is connected to the second connection portion 230, and the second edge portion 240 extends beyond the outer wall 130 of the cylinder body 120 when the second connection portion 230 is inserted into the cylinder body 120.
In the example shown in FIG. 5, the second flange 160 is designed to have a bent shape, and the second edge portion 240 of the second flange extends beyond the outer wall 130 of the cylinder body 120 when the second connection portion 230 is inserted into the cylinder body 120 (as shown in FIG. 3), such that the whole supporting cylinder 110 can provide support in axial and radial directions.
According to some embodiments of the present application, at least one hole (not shown in the figures) is provided in a wall portion of the cylinder body 120 for communicating the outer wall 130 and the inner wall 140. In some embodiments, the at least one hole may include a circular hole, a slotted hole or the like, and the shape and number of the hole are not limited in the present disclosure. In such a design, the encapsulating insulator 180 more easily reaches the inner wall 140 of the cylinder body 120 by means of passing through the at least one hole during casting, such that the winding assembly 100 has a better overall casting performance.
According to some embodiments of the present application, the present application provides a dry-type transformer including a winding assembly 100 described in the above embodiment.
The specific structure and function of the winding assembly 100 have been described in detail above, and will not be repeated herein for the sake of brevity.
Further refer to FIG. 6. FIG. 6 schematically shows a schematic structural diagram of a test fixture 600 for simulating the application of a fixed force according to an embodiment of the present application.
As shown in FIG. 6, the test fixture 600 for simulating the application of a fixed force includes four pressing arms 610, and the four pressing arms 610 respectively press the winding assembly 100 in a length direction of the winding assembly 100. The points where the four pressing arms 610 are respectively in contact with the upper end surface of the winding assembly 100 are marked as points A, B, C and D, respectively. Sections between points A, B, C and D on the winding assembly 100 are marked as A-B, B-C, C-D and D-A, respectively.

Comparative example 1: The winding assembly does not have a supporting cylinder, and the encapsulating insulator made of a silicone rubber directly encapsulates the coil. The test results of simulating the application of a fixed force are shown in Table 1.

Table 1

	Initial height (mm)	Height after compression (mm)	Change of height (mm)	Rate of change of height (%)
Pressed position
A	250	245	-5	-2.0
B	250	244	-6	-2.4
C	248	244	-4	-1.6
D	249	245	-4	-1.6
Average	249.3	244.5	-4.8	-1.9

Non-pressed position
A-B	249	247	-2	-0.8
B-C	248	245	-3	-1.2
C-D	249	247	-2	-0.8
D-A	249	248	-1	-0.4
Average	248.8	246.8	-2.0	-0.8

Embodiment 1: The winding assembly 100 has the supporting cylinder 110 (having a wall thickness of 1.5 mm), and the encapsulating insulator 180 made of a silicone rubber encapsulates the supporting cylinder 110 and the coil 170. The test results of simulating the application of a fixed force are shown in Table 2.

Table 2

	Initial height (mm)	Height after compression (mm)	Change of height (mm)	Rate of change of height (%)
Pressed position
A	498	496	-2	-0.4
B	501	498	-3	-0.6
C	501	498	-3	-0.6
D	502	501	-1	-0.2
Average	500.5	498.3	-2.3	-0.4

Non-pressed position
A-B	499	498	-1	-0.2
B-C	501	500	-1	-0.2
C-D	500	499.2	-0.8	0.0
D-A	500	500	0	0.0
Average	500.0	499.3	-0.7	-0.1

According to Table 1 and Table 2, the supporting cylinder 110 improves the overall mechanical supporting performance of the winding assembly 100: after the application of a fixed force is simulated, a vertical deformation of the pressed position decreases from 1.9% to 0.4%, and a vertical deformation of the non-pressed position decreases from 0.8% to 0.1%. In a case where the encapsulating insulator 180 is made of a silicone rubber, since the mechanical performance of silicone rubber casting is lower than that of epoxy resin casting, it is necessary to reinforce the whole structure by means of an internal supporting structure, namely the supporting cylinder 110. The use of the supporting cylinder 110 can reduce risks associated with low modulus silicone rubber materials for mechanical support.
Referring to FIG. 7, FIG. 7 schematically shows a flowchart of a method 700 for manufacturing a winding assembly according to an embodiment of the present application.
The method 700 includes steps S710 to S760.
At step S710, the cylinder body 120 of the supporting cylinder 110 is mounted on the second flange 160 of the supporting cylinder 110;

at step S720, the cylinder body 120 and the second flange 160 that are mounted together are sleeved on an inner mold;
at step S730, the coil 170 is wound around the outer wall 130 of the cylinder body 120;
at step S740, the first flange 150 of the supporting cylinder 110 is mounted on the cylinder body 120;
at step S750, the supporting cylinder 110 wound with the coil 170 is put into an outer mold, and a liquid encapsulating insulation material is casted to form the encapsulating insulator 180, wherein the encapsulating insulator 180 encapsulates the supporting cylinder 110 and the coil 170, such that the encapsulating insulator 180 is filled between the coil 170 and the outer wall 130 of the cylinder body 120, between the turns of the coil 170, between the coil 170 and the first flange 150, between the coil 170 and the second flange 160, and on the outer surface 190 of the first flange 150 and the inner wall 140 of the cylinder body 120; and
at step S760, the winding assembly 100 that has undergone casting and curing is taken out from the outer mold, and the inner mold is removed.

It should be finally noted that the forgoing embodiments are merely used for illustrating, rather than limiting, the technical solutions of the present application; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that the technical solutions specified in the foregoing embodiments could still be modified, or equivalent replacements for some or all of the technical features thereof could be made; and such modifications or replacements do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application, and should be encompassed within the scope of the description and claims of the present application. In particular, the technical features mentioned in the embodiments can be combined in any manner as long as there is no structural conflict. The present application is not limited to the specific embodiments disclosed herein but includes all the technical solutions that fall within the scope of the claims.

Claims

A winding assembly (100), comprising:
a supporting cylinder (110), comprising:
a cylinder body (120) extending in a first direction (X), the cylinder body (120) having an outer wall (130) and an inner wall (140); and

a first flange (150) and a second flange (160), the first flange (150) and the second flange (160) being respectively arranged at a first end and a second end of the cylinder body (120) that are opposite each other in the first direction (X);

a coil (170), the coil (170) being wound around the outer wall (130) of the cylinder body (120) in the first direction (X); and

an encapsulating insulator (180), the encapsulating insulator (180) encapsulating the supporting cylinder (110) and the coil (170), such that the encapsulating insulator (180) is filled between the coil (170) and the outer wall (130) of the cylinder body (120), between turns of the coil (170), between the coil (170) and the first flange (150), between the coil (170) and the second flange (160), and on an outer surface (190) of the first flange (150) and the inner wall (140) of the cylinder body (120).
The winding assembly (100) according to claim 1, wherein the first flange (150) comprises:
a first connection portion (200) configured to be inserted into the cylinder body (120), so as to sleeve the cylinder body (120) outside the first connection portion (200); and

a first edge portion (210) connected to the first connection portion (200), the first edge portion (210) extending beyond the outer wall (130) of the cylinder body (120) when the first connection portion (200) is inserted into the cylinder body (120).
The winding assembly (100) according to claim 2, wherein at least one notch (220) extending in a circumferential direction of the first flange (150) is provided in the first flange (150).
The winding assembly (100) according to claim 3, wherein the notch (220) extends through the first connection portion (200), and the notch (220) partially extends in the first edge portion (210).
The winding assembly (100) according to claim 1, wherein the second flange (160) comprises:
a second connection portion (230) configured to be inserted into the cylinder body (120), so as to sleeve the cylinder body (120) outside the second connection portion (230); and

a second edge portion (240) connected to the second connection portion (230), the second edge portion (240) extending beyond the outer wall (130) of the cylinder body (120) when the second connection portion (230) is inserted into the cylinder body (120).
The winding assembly (100) according to any one of claims 1-5, wherein the encapsulating insulator (180) is made of an elastomeric insulation material.
The winding assembly (100) according to claim 6, wherein the elastomeric insulation material comprises a silicone rubber.
The winding assembly (100) according to any one of claims 1-5, wherein the cylinder body (120), the first flange (150) and the second flange (160) are made of a rigid insulation material.
The winding assembly (100) according to claim 8, wherein the rigid insulation material comprises an epoxy fiberglass material.
The winding assembly (100) according to any one of claims 1-5, wherein the coil (170) comprises at least one of a disk winding or a drop winding.
The winding assembly (100) according to any one of claims 1-5, wherein a primer is applied on a surface of the cylinder body (120).
The winding assembly (100) according to any one of claims 1-5, wherein at least one hole is provided in a wall portion of the cylinder body (120) for communicating the outer wall (130) and the inner wall (140).
A dry-type transformer, comprising a winding assembly (100) according to any one of claims 1-12.
A method for manufacturing a winding assembly (100) according to any one of claims 1-12, the method including:
mounting a cylinder body (120) of a supporting cylinder (110) on a second flange (160) of the supporting cylinder (110);

sleeving the cylinder body (120) and the second flange (160) that are mounted together on an inner mold;

winding a coil (170) around an outer wall (130) of the cylinder body (120);

mounting a first flange (150) of the supporting cylinder (110) on the cylinder body (120);

putting the supporting cylinder (110) wound with the coil (170) into an outer mold, and casting a liquid encapsulating insulation material to form an encapsulating insulator (180), wherein the encapsulating insulator (180) encapsulates the supporting cylinder (110) and the coil (170), such that the encapsulating insulator (180) is filled between the coil (170) and the outer wall (130) of the cylinder body (120), between turns of the coil (170), between the coil (170) and the first flange (150), between the coil (170) and the second flange (160), and on an outer surface (190) of the first flange (150) and an inner wall (140) of the cylinder body (120); and

taking out from the outer mold the winding assembly (100) that has undergone casting and curing, and removing the inner mold.