Foil winding suitable for voltage class above 10kV and transformer comprising foil winding

Abstract

The utility model relates to a foil winding suitable for voltage classes above 10kV and a transformer comprising the foil winding. The foil type winding suitable for the voltage class above 10kV comprises an inner side insulation part, an outer side insulation part and an outer side insulation part, the plurality of coil cakes are arranged at intervals along the axial direction of the inner side insulating part, and each coil cake is formed by winding a metal foil on the peripheral surface of the inner side insulating part; the number of turns of the coil cakes is distributed in a non-increasing mode and the radial thickness of the inner side insulation part is distributed in a non-decreasing mode from the axial center of the inner side insulation part to the two ends, and the coil cakes comprise a first coil cake closest to the first end of the two ends and a second coil cake adjacent to the first coil cake. The number of turns of the first coil cake is smaller than that of the second coil cake, and the radial thickness of the inner side insulation part at the first coil cake is larger than that of the inner side insulation part at the second coil cake, so that the effects that the insulation performance of the foil type winding is improved, local temperature rise is restrained, meanwhile, the size is miniaturized, and the manufacturing cost is not increased are achieved.

Description

Technical Field

[0001] The present application relates to a foil winding for a transformer, and more specifically, to a foil winding suitable for a voltage level above 10 kV and a transformer including the same, wherein the insulation performance can be improved and local temperature rise can be suppressed by improving the structure of the foil winding. Background Art

[0002] Figure 1 A schematic cross-sectional structure diagram of a conventional foil high-voltage winding is shown. As Figure 1 shown, the conventional foil high-voltage winding 100' sequentially includes a conventional inner insulation part 110', a plurality of conventional coil pancakes 120', and a conventional outer insulation part 130' from the inside to the outside along the radial direction. The conventional inner insulation part 110' is a hollow cylinder with uniform dimensions for sleeving on a transformer iron core. The plurality of conventional coil pancakes 120' are arranged at intervals along the axial direction on the outer surface of the conventional inner insulation part 110', and are symmetrically arranged up and down with the axial center as the reference. The number of turns of all the coil pancakes is equal. The conventional outer insulation part 130' surrounds the plurality of conventional coil pancakes 120' from the outside in the radial direction.

[0003] However, such a conventional foil high-voltage winding 100' has the following problems: at the electric field level, at the head and tail ends of the winding, due to sudden changes in the conductor geometry or proximity to grounded components (such as the iron core, shielding layer), the electric field intensity increases locally. This electric field distortion makes the end region a weak point of insulation. In the lightning impulse test or power frequency withstand voltage test, the conventional foil high-voltage winding is prone to local insulation breakdown failure due to the concentration of the field strength at the winding ends, restricting the operation reliability and insulation life of the equipment. At the electromagnetic level, the sudden truncation or turning of the conductor arrangement at the head and tail ends of the coil destroys the continuity of the magnetic field lines, resulting in a significant increase in the leakage magnetic field intensity and forming strong eddy currents. The Joule heat loss generated by the strong eddy currents causes the temperature rise at the ends to be significantly higher than other regions of the winding, causing local heating at the ends and accelerating insulation aging.

[0004] Currently, the following methods are usually adopted to solve the above problems: One method is to add a non-magnetic conductive shielding ring (such as a copper strip) or a magnetic silicon steel sheet at the ends of the winding, but this will cause the overall thickness of the coil to increase, increasing the size of the winding and the transformer; another method is to chamfer the right-angle edges of the metal foil ends of the coil pancakes, but this will increase the process complexity and thus increase the manufacturing cost.

[0005] In view of this, it is desirable to provide an improved foil high-voltage winding that can improve the insulation performance of the winding and suppress local temperature rise in a simple manner, while achieving miniaturization of the size of the winding and the transformer and reduction of the manufacturing cost. Summary of the Utility Model

[0006] The present application is proposed in view of the above problems. The main object of the present application is to provide a foil winding and a transformer including the same, so as to at least solve the technical problem in the prior art that it is difficult to miniaturize the size of the foil winding and the transformer and reduce the manufacturing cost while improving the insulation performance of the foil winding and suppressing the local temperature rise of the foil winding.

[0007] To achieve the above object, according to one aspect of the present application, there is provided a foil winding applicable to a voltage level above 10 kV. The foil winding applicable to a voltage level above 10 kV includes: an inner insulation part, which is in a hollow cylindrical shape; a plurality of coil pancakes, each coil pancake is formed by winding a conductive foil around the outer peripheral surface of the inner insulation part, and the plurality of coil pancakes are arranged at intervals along the axial direction of the inner insulation part; from the center in the axial direction of the inner insulation part towards both ends in the axial direction, the number of turns of the coil pancakes is distributed non-increasingly, while the radial thickness of the inner insulation part is distributed non-decreasingly. Both ends in the axial direction of the inner insulation part include a first end. The plurality of coil pancakes include a first coil pancake closest to the first end and a second coil pancake adjacent to the first coil pancake. The number of turns of the first coil pancake is less than that of the second coil pancake, and the radial thickness of the inner insulation part at the first axial position where the first coil pancake is located is greater than the radial thickness of the inner insulation part at the second axial position where the second coil pancake is located.

[0008] In this way, for a transformer with a voltage level above 10 kV, by adopting the design of decreasing the number of turns of the coil pancakes and increasing the thickness of the inner insulation part at at least one end in the axial direction of the foil winding, the distribution of the end electric field can be significantly improved, and the insulation performance can be enhanced. This design enables the position with the most severe electric field distortion to obtain a thicker insulation layer, thereby increasing the insulation strength and preventing insulation breakdown during the lightning impulse test or the withstand voltage test. At the same time, at the position where the eddy current is the most severe, the number of turns of the coil pancakes is minimized, reducing the distorted magnetic field intensity at the end and the amount of conductor used at the end, thereby reducing the DC resistance loss and eddy current loss at the end and lowering the local temperature rise. In addition, this structural optimization does not require complex processes, avoids an increase in manufacturing costs, and helps to maintain the compact size of the transformer.

[0009] Furthermore, according to an embodiment of the present application, the plurality of coil pancakes are symmetrically distributed with respect to the axial center plane. The axial center plane is a plane passing through the center in the axial direction of the inner insulation part and perpendicular to the axial direction. Both ends in the axial direction of the inner insulation part further include a second end opposite to the first end. The plurality of coil pancakes include a third coil pancake closest to the second end and a fourth coil pancake adjacent to the third coil pancake. The number of turns of the third coil pancake is less than that of the fourth coil pancake, and the radial thickness of the inner insulation part at the third axial position where the third coil pancake is located is greater than the radial thickness of the inner insulation part at the fourth axial position where the fourth coil pancake is located.

[0010] In this way, multiple coil pancakes are symmetrically distributed, and at both ends in the axial direction of the foil winding, a design of decreasing the number of turns of the coil pancakes and increasing the thickness of the inner insulation part is adopted. Thus, enhanced insulation strength can be obtained at both ends where the electric field distortion is the most severe, and the DC resistance loss and eddy current loss can be reduced, and the local temperature rise can be decreased.

[0011] Furthermore, according to an embodiment of the present application, for any one coil pancake and any other coil pancake among the multiple coil pancakes: the sum of the radial thickness of any one coil pancake and the radial thickness of the inner insulation part at the axial position where any one coil pancake is located is equal to the sum of the radial thickness of any other coil pancake and the radial thickness of the inner insulation part at the axial position where any other coil pancake is located.

[0012] In this way, the thickness uniformity of the foil winding in the axial direction can be ensured, and the additional space requirements or manufacturing difficulties caused by the thickness change of the insulation part or the coil pancake can be avoided. The constant total radial thickness in the axial direction helps to maintain the compactness of the foil winding, reduce the overall size of the transformer, and at the same time ensure the electrical performance and heat dissipation efficiency.

[0013] Furthermore, according to an embodiment of the present application, the foil winding applicable to a voltage level above 10 kV further includes: an outer insulation part, which is arranged on the outer side of the multiple coil pancakes in the radial direction and surrounds the multiple coil pancakes. For any one coil pancake and any other coil pancake among the multiple coil pancakes: the sum of the radial thickness of any one coil pancake, the radial thickness of the inner insulation part at the axial position where any one coil pancake is located, and the radial thickness of the outer insulation part at the axial position where any one coil pancake is located is equal to the sum of the radial thickness of any other coil pancake, the radial thickness of the inner insulation part at the axial position where any other coil pancake is located, and the radial thickness of the outer insulation part at the axial position where any other coil pancake is located.

[0014] In this way, the arrangement of the outer insulation part ensures the integrity and stability of the overall structure of the foil winding. Along the axial direction, the total radial thickness including the radial thickness of the coil pancake, the inner insulation part, and the outer insulation part remains unchanged, ensuring the uniformity of the overall size of the foil winding in the axial direction, and avoiding the additional space requirements or manufacturing difficulties caused by the thickness change of the insulation part or the coil pancake. The constant total radial thickness helps to maintain the compactness of the foil winding, reduce the overall size of the transformer, and at the same time ensure the electrical performance and heat dissipation efficiency.

[0015] Furthermore, according to an embodiment of the present application, from the center in the axial direction of the inner insulation part towards both ends in the axial direction, the radial thickness of the outer insulation part is distributed in an increasing manner.

[0016] In this way, on the premise of ensuring that the total radial thickness including the radial thickness of the coil pancakes, the inner insulation part and the outer insulation part remains unchanged along the axial direction, from the center in the axial direction towards both ends, the radial thickness of the outer insulation part itself can be distributed in an increasing manner. At this time, the radial thickness of the coil pancakes and the corresponding inner insulation part can then be distributed in a decreasing manner. That is, on the premise of ensuring the compact size of the foil winding, the radial thicknesses of the inner insulation part and the outer insulation part can be flexibly arranged as needed.

[0017] Furthermore, according to an embodiment of the present application, the centers of multiple coil pancakes are located on a straight line in the radial direction.

[0018] In this way, without making the sum of the radial thickness of the coil pancakes and the radial thickness of the corresponding inner insulation part remain unchanged along the axial direction, it is also possible to achieve that the overall radial thickness of the foil winding remains unchanged along the axial direction.

[0019] Furthermore, according to an embodiment of the present application, from the center in the axial direction of the inner insulation part towards both ends in the axial direction, the number of turns of at least two adjacent coil pancakes is equal.

[0020] In this way, from the center in the axial direction of the inner insulation part towards both ends in the axial direction, the number of turns of at least two adjacent coil pancakes is equal, and at the same time, the number of turns of the first coil pancake closest to the first end is less than the number of turns of the second coil pancake adjacent to the first coil pancake. Therefore, from the center in the axial direction of the inner insulation part towards both ends in the axial direction, the non-increasing distribution of the number of turns of the coil pancakes is specifically manifested as partially equal and partially decreasing.

[0021] Furthermore, according to an embodiment of the present application, from the center in the axial direction of the inner insulation part towards both ends in the axial direction, the number of turns of the coil pancakes is distributed in a decreasing manner.

[0022] In this way, the non-increasing distribution of the number of turns of the coil pancakes is specifically manifested as a decreasing distribution. The eddy current of the foil winding is mainly concentrated at both ends, and the influence of the eddy current near the center of the foil winding is relatively small. By making the number of turns of the coil pancakes strictly decrease from the center in the axial direction towards both ends, the change in the number of turns of the coil pancakes can match the severity of the eddy current at different positions of the foil winding in the axial direction. Thus, the eddy current loss of the foil winding can be optimally reduced, the local temperature rise can be lowered, and thereby the electrical performance of the foil winding can be optimized.

[0023] Furthermore, according to an embodiment of the present application, from the center in the axial direction of the inner insulation part towards both ends in the axial direction, the radial thickness of the inner insulation part is distributed in an increasing manner.

[0024] In this way, the non-decreasing distribution of the radial thickness of the inner insulating part is specifically manifested as an increasing distribution. The electric field distortion of the foil winding is mainly concentrated at both ends, and the electric field distortion near the center of the foil winding is very small. By making the radial thickness of the inner insulating part increase strictly from the center in the axial direction towards both ends, the insulating thickness can match the required insulation strength at different axial positions of the foil winding. Thus, the insulation performance of the foil winding can be optimally enhanced, and insulation breakdown caused by electric field distortion can be prevented.

[0025] According to another aspect of the present application, a transformer is provided, which includes the above-mentioned foil winding applicable to voltage levels above 10 kV.

[0026] In an embodiment of the present application, a foil winding applicable to voltage levels above 10 kV and a transformer including the same are provided. The foil winding applicable to voltage levels above 10 kV includes: an inner insulating part, which is in a hollow cylindrical shape; a plurality of coil pancakes, each of which is formed by winding a conductive foil around the outer peripheral surface of the inner insulating part, and the plurality of coil pancakes are arranged at intervals along the axial direction of the inner insulating part; from the center in the axial direction of the inner insulating part towards both ends in the axial direction, the number of turns of the coil pancakes shows a non-increasing distribution, while the radial thickness of the inner insulating part shows a non-decreasing distribution. Both ends in the axial direction of the inner insulating part include a first end. The plurality of coil pancakes include a first coil pancake closest to the first end and a second coil pancake adjacent to the first coil pancake. The number of turns of the first coil pancake is less than that of the second coil pancake, and the radial thickness of the inner insulating part at the first axial position where the first coil pancake is located is greater than the radial thickness of the inner insulating part at the second axial position where the second coil pancake is located, so as to at least solve the technical problem in the prior art that it is difficult to improve the insulation performance of the foil winding and suppress the local temperature rise of the foil winding while realizing the miniaturization of the size of the foil winding and the transformer and the reduction of the manufacturing cost, thereby achieving the technical effect of improving the insulation performance of the foil winding and suppressing the local temperature rise of the foil winding without complex processes and cost increase, while maintaining the compact size of the foil winding and the transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The schematic diagrams in the specification forming a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation of the present application. In the drawings:

[0028] Figure 1 is a schematic cross-sectional structure diagram of a traditional foil high-voltage winding;

[0029] Figure 2 is a schematic cross-sectional structure diagram of a foil winding applicable to voltage levels above 10 kV according to the first embodiment of the present application;

[0030] Figure 3 It is a schematic cross-sectional structure diagram of a foil winding applicable to voltage levels above 10 kV according to the second embodiment of the present application;

[0031] Figure 4 It is a schematic cross-sectional structure diagram of a foil winding applicable to voltage levels above 10 kV according to the third embodiment of the present application; and

[0032] Figure 5 It is a schematic cross-sectional structure diagram of a foil winding applicable to voltage levels above 10 kV according to the fourth embodiment of the present application.

[0033] Among them, the above-mentioned drawings include the following reference numerals:

[0034] Specific embodiments

[0035] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0036] It should be pointed out that unless otherwise specified, all technical and scientific terms used in the present application have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0037] In the present application, unless otherwise stated, the orientation words such as "upper, lower, top, bottom" are usually in the directions shown in the drawings, or in the vertical, perpendicular or gravitational directions of the components themselves; similarly, for ease of understanding and description, "inner, outer" refer to the inner and outer of the contours of the components themselves, but the above orientation words are not used to limit the present application.

[0038] The purpose of the present application is to provide a foil winding and a transformer including the same, especially a foil winding applicable to voltage levels above 10 kV and a transformer including the same. Through optimized structural design, the foil winding can improve the insulation performance of the foil winding and suppress local temperature rise without complex processes, and can also avoid increasing the size and manufacturing cost of the foil winding and the transformer.

[0039] In the present application, the foil winding applicable to voltage levels above 10 kV can be, for example, a foil winding applicable to voltage levels above 35 kV, or a foil winding applicable to voltage levels above 66 kV. The transformer including the foil winding applicable to voltage levels above 10 kV can be, for example, a resin-cast (dry type) distribution transformer.

[0040] Figure 2It is a schematic cross-sectional structure diagram of a foil winding applicable to a voltage level above 10 kV according to the first embodiment of the present application. As Figure 2 shown, the foil winding 100 applicable to a voltage level above 10 kV includes: an inner insulation part 110, which is in a hollow cylindrical shape; a plurality of coil pancakes 120, each of which is formed by winding a conductive foil around the outer peripheral surface of the inner insulation part 110, wherein the plurality of coil pancakes 120 are arranged at intervals along the axial direction of the inner insulation part 110; wherein, from the center in the axial direction of the inner insulation part 110 towards both ends in the axial direction, the number of turns of the coil pancakes is distributed non-increasingly, while the radial thickness of the inner insulation part 110 is distributed non-decreasingly, wherein the two ends in the axial direction of the inner insulation part 110 include a first end, the plurality of coil pancakes 120 include a first coil pancake 1201 closest to the first end and a second coil pancake 1202 adjacent to the first coil pancake, the number of turns of the first coil pancake 1201 is less than the number of turns of the second coil pancake 1202, and the radial thickness of the inner insulation part 110 at the first axial position where the first coil pancake 1201 is located is greater than the radial thickness of the inner insulation part 110 at the second axial position where the second coil pancake 1202 is located.

[0041] By having the number of turns of the coil pancakes distributed non-increasingly and the radial thickness of the inner insulation part 110 distributed non-decreasingly from the center in the axial direction towards both ends in the axial direction, and making the number of turns of the first coil pancake 1201 closest to the first end less than the number of turns of the second coil pancake 1202, and the radial thickness of the inner insulation part 110 at the first axial position where the first coil pancake 1201 is located greater than the radial thickness of the inner insulation part 110 at the second axial position where the second coil pancake 1202 is located, in the present application, among the plurality of coil pancakes 120, the first coil pancake 1201 has the smallest number of turns, and at the same time the inner insulation part 110 has the largest radial thickness at the first coil pancake 1201. In addition, the coil pancakes closest to the center in the axial direction ( Figure 2 in this case are the sixth coil pancake 1206 and the eighth coil pancake 1208) have the largest number of turns, and at the same time the inner insulation part 110 has the smallest radial thickness at such coil pancakes.

[0042] It is known that in a transformer, the two ends of the high-voltage winding in the axial direction are the positions with the most severe electric field distortion and the most severe eddy current. Through the above structural design, in the foil winding 100 applicable to voltage levels above 10 kV, the inner insulation part 110 has the largest radial thickness at the first coil pancake 1201 closest to the first end. Therefore, the insulation thickness is increased at the position with the most severe electric field distortion (which is also the weakest insulation position), thereby increasing the insulation strength. In addition, through the above structural design, the first coil pancake 1201 closest to the first end has the smallest number of turns. Therefore, the number of turns of the coil pancake is minimized at the position with the most severe eddy current, reducing the distorted magnetic field intensity at the end and the amount of conductor used at the end, thereby minimizing the DC resistance loss and eddy current loss at the end and reducing the local temperature rise. Additionally, it is known that the electric field distortion and eddy current are not obvious near the center of the high-voltage winding in the axial direction. Although the above structural design increases the number of turns of the coil pancake near the center in the axial direction and reduces the radial thickness of the inner insulation part 110 near the center in the axial direction, the reduction in the radial thickness of the inner insulation part 110 near the center in the axial direction also shortens the heat dissipation path of the coil pancake at the corresponding position. As a result, the changes in the insulation strength and the temperature rise caused by eddy current near the center in the axial direction are not obvious. Thus, compared with the traditional foil high-voltage winding 100' and the traditional transformer including it, the foil winding 100 applicable to voltage levels above 10 kV and the transformer including it with the above structural design can have improved electrical performance.

[0043] In addition, compared with the traditional structural design, the above structure adopted in this application can maintain the compact size of the foil winding 100 and the transformer applicable to voltage levels above 10 kV without additional components, and can suppress the increase in manufacturing cost due to its simple form.

[0044] On the other hand, in a transformer using the above foil winding 100 for voltage levels above 10 kV as the high-voltage winding, if the same insulation performance as that of the traditional transformer is to be achieved (i.e., maintaining the same end electric field intensity), the main insulation distance between the high- and low-voltage windings and the phase-to-phase insulation distance of the high-voltage winding can be reduced. Thus, the size of the transformer can be reduced, and the material cost of the transformer can be lowered.

[0045] In Figure 2 , a plurality of coil pancakes 120 are shown to include 8 coil pancakes. It should be noted that this quantity is only an example, and this application is not limited thereto. For example, in this application, the plurality of coil pancakes 120 may also include other quantities of coil pancakes such as 3, 4, 5, 6, 9, 12, etc. In addition, in Figure 2 , the axial direction is the vertical direction, and the radial direction is the horizontal direction.

[0046] Furthermore, asFigure 2 As shown, the multiple coil pancakes are symmetrically distributed with respect to the axial center plane S, which is a plane passing through the center in the axial direction of the inner insulating part 110 and perpendicular to the axial direction. At this time, the number of coil pancakes in the multiple coil pancakes 120 is an even number. For example, in the present application, in addition to 8 coil pancakes, the multiple coil pancakes 120 may also include other even numbers of coil pancakes such as 4, 6, 10, 12, 16, etc.

[0047] Furthermore, in the present application, both ends in the axial direction of the inner insulating part 110 further include a second end ( Figure 2 opposite to the first end ( Figure 2 the top end in the axial direction of the inner insulating part 110 in

[0048] In this way, similar to the structural design near the first end in the axial direction of the inner insulating part 110, the insulation thickness is increased and the number of turns of the coil pancakes is minimized at the second end (i.e., the position where the other electric field distortion is the most serious and the eddy current is the most serious) of the foil winding 100 applicable to voltage levels above 10 kV, thereby increasing the insulation strength at the second end and minimizing the heat loss caused by eddy currents.

[0049] In addition, not only can the positions of the multiple coil pancakes 120 be symmetrically distributed with respect to the axial center plane S, but also the number of turns of the multiple coil pancakes 120 can be symmetrically distributed with respect to the axial center plane S. That is, the number of turns of the first coil pancake 1201 can be equal to the number of turns of the third coil pancake 1203, and the number of turns of the second coil pancake 1202 can be equal to the number of turns of the fourth coil pancake 1204.

[0050] It should be noted that in the present application, the positions of the multiple coil pancakes 120 may not be symmetrically distributed with respect to the axial center plane S. At this time, the number of coil pancakes in the multiple coil pancakes 120 can be an odd number. In addition, regardless of how the positions of the multiple coil pancakes 120 are distributed, the number of turns of the multiple coil pancakes 120 may not be symmetrically distributed with respect to the axial center plane S, that is, the number of turns of the first coil pancake 1201 can be unequal to the number of turns of the third coil pancake 1203, and the number of turns of the second coil pancake 1202 can be unequal to the number of turns of the fourth coil pancake 1204.

[0051] In the present application, from the center in the axial direction of the inner insulating portion 110 towards both ends in the axial direction, the number of turns of the coil pancakes is non-increasingly distributed, meaning that: from the center in the axial direction of the inner insulating portion 110 towards any one of the two ends in the axial direction, the number of turns of any coil pancake is not greater than (i.e., equal to or less than) the number of turns of the previous coil pancake of that coil pancake. This non-increasing distribution includes a decreasing distribution and a partially decreasing distribution with equal parts.

[0052] Furthermore, in the partially decreasing distribution with equal parts, from the center in the axial direction of the inner insulating portion 110 towards any one of the two ends in the axial direction, the number of turns of at least two adjacent coil pancakes is equal.

[0053] As a first embodiment, Figure 2 The figure illustrates a partially decreasing distribution. As Figure 2 shown, the number of turns of the sixth coil pancake 1206 (which is the coil pancake closest to the center in the axial direction of the inner insulating portion 110) is equal to the number of turns of the fifth coil pancake 1205, the number of turns of the second coil pancake 1202 is less than the number of turns of the fifth coil pancake 1205, and the number of turns of the first coil pancake 1201 is less than the number of turns of the second coil pancake 1202. In addition, the number of turns of the eighth coil pancake 1208 is equal to the number of turns of the seventh coil pancake 1207, the number of turns of the fourth coil pancake 1204 is less than the number of turns of the seventh coil pancake 1207, and the number of turns of the third coil pancake is less than the number of turns of the fourth coil pancake 1204.

[0054] Alternatively, Figure 2 the number of turns of the coil pancakes in

[0055] can also have the following arrangement: the number of turns of the sixth coil pancake 1206 is equal to the number of turns of the fifth coil pancake 1205, the number of turns of the second coil pancake 1202 is equal to the number of turns of the fifth coil pancake 1205, the number of turns of the first coil pancake 1201 is less than the number of turns of the second coil pancake 1202, the number of turns of the eighth coil pancake 1208 is equal to the number of turns of the seventh coil pancake 1207, the number of turns of the fourth coil pancake 1204 is equal to the number of turns of the seventh coil pancake 1207, and the number of turns of the third coil pancake 1203 is less than the number of turns of the fourth coil pancake 1204.

[0056] In the present application, from the center in the axial direction of the inner insulating portion 110 towards both ends in the axial direction, the radial thickness of the inner insulating portion 110 shows a non-decreasing distribution, which means that: from the center in the axial direction of the inner insulating portion 110 towards any one of the two ends in the axial direction, the radial thickness of the inner insulating portion 110 at the axial position where any coil pancake is located is not less than (i.e., equal to or greater than) the radial thickness of the inner insulating portion 110 at the axial position where the previous coil pancake of the any coil pancake is located. This non-decreasing distribution includes an increasing distribution and a partially increasing distribution with equal parts.

[0057] As Figure 2 shown, at the axial positions of the fifth coil pancake 1205, the sixth coil pancake 1206, the eighth coil pancake 1208, and the seventh coil pancake 1207, the radial thickness of the inner insulating portion 110 remains unchanged; while from the fifth coil pancake 1205 to the second coil pancake 1202, and then to the first coil pancake 1201, the radial thickness of the inner insulating portion 110 gradually decreases, and from the seventh coil 1207 to the fourth coil pancake 1204, and then to the third coil pancake 1203, the radial thickness of the inner insulating portion 110 gradually decreases. That is to say, in the first embodiment of the present application, the radial thickness of the inner insulating portion 110 at the two end portions in the axial direction is larger than the radial thickness of the inner insulating portion 110 near the center in the axial direction, and at the same time, the radial thickness of the inner insulating portion 110 near the center in the axial direction is uniform. It should be noted that the turn difference between the fifth coil pancake 1205 and the second coil pancake 1202 may be equal to the turn difference between the second coil pancake 1202 and the first coil pancake 1201, or may not be equal to the turn difference between the second coil pancake 1202 and the first coil pancake 1201.

[0058] Furthermore, as Figure 2 shown, for any two coil pancakes among the multiple coil pancakes 120, the sum of the radial thickness of one coil pancake and the radial thickness of the inner insulating portion 110 at the axial position where the coil pancake is located is equal to the sum of the radial thickness of the other coil pancake and the radial thickness of the inner insulating portion 110 at the axial position where the other coil pancake is located. In this way, compared with the traditional design, the sum of the thickness of the coil pancake and the thickness of the inner insulating portion 110 of the foil winding 100 applicable to voltage levels above 10 kV in the radial direction will not increase, and thus the size of the foil winding 100 applicable to voltage levels above 10 kV will not increase.

[0059] Furthermore, as Figure 2As shown, the foil winding 100 applicable to voltage levels above 10 kV further includes: an outer insulation part 130, arranged on the outer side of the plurality of coil pancakes 120 in the radial direction and surrounding the plurality of coil pancakes 120. Among them, for any two coil pancakes in the plurality of coil pancakes 120, the sum of the radial thickness of one coil pancake, the radial thickness of the inner insulation part 110 at the axial position where the coil pancake is located, and the radial thickness of the outer insulation part 130 at the axial position where the coil pancake is located is equal to the sum of the radial thickness of the other coil pancake, the radial thickness of the inner insulation part 110 at the axial position where the other coil pancake is located, and the radial thickness of the outer insulation part 130 at the axial position where the other coil pancake is located. In this way, compared with the traditional design, the overall thickness of the foil winding 100 applicable to voltage levels above 10 kV in the radial direction will not increase, so that the size of the foil winding 100 applicable to voltage levels above 10 kV and the transformer including it will not increase.

[0060] In this application, the outer insulation part 130 can be formed by an insulating resin (such as epoxy resin) through a casting process to encapsulate the inner insulation part 110 and the plurality of coil pancakes 120. The inner insulation part 110 can include a plurality of inner insulation blocks wound by a plurality of insulating films at corresponding axial positions of the plurality of coil pancakes. The inner insulation part 110 can also include epoxy resin-impregnated glass fibers (not shown in the figure) located radially inside the plurality of inner insulation blocks. The outer insulation part 130 can fill the gaps between adjacent coil pancakes in the plurality of coil pancakes 120 and the gaps between the plurality of inner insulation blocks in the inner insulation part 110. In addition, in this application, the conductive foil can be a metal foil, such as a copper foil or an aluminum foil. An interlayer insulation film can also be provided between adjacent layers of the conductive foil, and the interlayer insulation film can be formed by a polyester film (PET), a polyimide (PI), or Nomex paper.

[0061] Figure 3 It is a schematic cross-sectional structure diagram of a foil winding applicable to voltage levels above 10 kV according to the second embodiment of the present application. Figure 3 The structure of the foil winding 100 shown applicable to voltage levels above 10 kV is similar to that in Figure 2 The difference is only that: in Figure 3 , from the center in the axial direction of the inner insulation part 110 towards both ends in the axial direction, the number of turns of the coil pancakes is distributed in a decreasing manner; in addition, from the center in the axial direction of the inner insulation part 110 towards both ends in the axial direction, the radial thickness of the inner insulation part 110 is distributed in an increasing manner.

[0062] Through Figure 3In the above structural design, through the strictly decreasing distribution of the number of turns of the coil pancakes from the axial center towards both ends, and the strictly increasing distribution of the radial thickness of the inner insulation part from the axial center towards both ends, the change in the number of turns of the coil pancakes can match the change in the severity of eddy currents of the foil winding in the axial direction, and the insulation thickness can match the required insulation strength of the foil winding in the axial direction. Thus, the insulation performance of the foil winding can be optimally improved, the eddy current loss of the foil winding can be reduced, and the local temperature rise can be decreased, thereby optimally optimizing the electrical performance of the foil winding. It should be noted that in Figure 3 the number of turns difference between adjacent coil pancakes can be equal or unequal, and the present application does not limit this.

[0063] In Figure 2 and Figure 3 in the illustrated embodiment, for any two coil pancakes among the multiple coil pancakes 120, the sum of the radial thickness of one coil pancake and the radial thickness of the inner insulation part 110 at the axial position where this coil pancake is located is equal to the sum of the radial thickness of the other coil pancake and the radial thickness of the inner insulation part 110 at the axial position where the other coil pancake is located. Correspondingly, the radial thickness of the outer insulation part 130 at the positions corresponding to different coil pancakes can also be equal. However, the present application is not limited to this, and at the axial position where each coil pancake is located, the sum of the radial thickness of this coil pancake and the radial thickness of the inner insulation part 110 at the same axial position can also be variable. In particular, the centers of all coil pancakes in the radial direction can be located on the same straight line.

[0064] Figure 4 is a schematic cross-sectional structure diagram of a foil winding applicable to a voltage level above 10 kV according to the third embodiment of the present application. Figure 4 The number of turns of each coil pancake in the illustrated foil winding 100 applicable to a voltage level above 10 kV is the same as that of the coil pancake at the corresponding position in Figure 2 , the difference is that: in Figure 4 the centers of the coil pancake 1201, coil pancake 1202, coil pancake 1205, coil pancake 1206, coil pancake 1208, coil pancake 1207, coil pancake 1204, and coil pancake 1203 in the radial direction are located on the same straight line. In addition, in Figure 4 from the center in the axial direction towards both ends, the radial thickness of the outer insulation part 130 shows an increasing distribution.

[0065] Through Figure 4 the above structural design in, the same technical effects achieved by the foil winding 100 shown in Figure 2 applicable to a voltage level above 10 kV can be achieved, and details are not described herein again.

[0066] Figure 5It is a schematic cross-sectional structure diagram of a foil winding suitable for voltage levels above 10 kV according to the fourth embodiment of the present application. Figure 5 The structure of the foil winding 100 shown in the figure is suitable for voltage levels above 10 kV. Figure 4 is similar to Figure 5 In the figure, the number of turns of the coil cake is distributed decreasingly from the center of the inner insulating part 110 in the axial direction toward the two ends in the axial direction; in addition, the radial thickness of the inner insulating part 110 is distributed increasingly from the center of the inner insulating part 110 in the axial direction toward the two ends in the axial direction.

[0067] pass Figure 5 The above structural design can achieve Figure 3 The same technical effects achieved by the foil winding 100 with a voltage level of 10 kV or above are not described in detail here.

[0068] It should be noted that in this application Figures 2 to 5 The number of coil cakes described (ie, 8) is only an example, and those skilled in the art will appreciate that under the structural design described in the present application, the number of coil cakes may also be 4, 6, 9, 10, 12, 16, or other numbers.

[0069] The present application also provides a transformer, which includes the above foil winding 100 applicable to voltage levels above 10 kV. In the transformer, the above foil winding 100 applicable to voltage levels above 10 kV can be used as a high-voltage winding. The improved structural design and technical effects of the transformer compared to the prior art can be referred to the above for Figures 2 to 5 The description will not be repeated here.

[0070] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0071] It should be noted that the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the application described herein can be implemented in an order other than those illustrated or described herein. The nouns and pronouns related to people in this patent application are not limited to specific genders.

[0072] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various modifications and changes can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A foil winding applicable to voltage levels above 10 kV, characterized in that, The foil winding (100) applicable to voltage levels above 10 kV includes: An inner insulation part (110), which is in the shape of a hollow cylinder; A plurality of coil pancakes (120), each of which is formed by winding a conductive foil around the outer peripheral surface of the inner insulation part (110), and the plurality of coil pancakes (120) are arranged at intervals along the axial direction of the inner insulation part (110); From the center in the axial direction of the inner insulation part (110) towards both ends in the axial direction, the number of turns of the coil pancakes shows a non-increasing distribution, while the radial thickness of the inner insulation part (110) shows a non-decreasing distribution. Both ends in the axial direction of the inner insulation part (110) include a first end. The plurality of coil pancakes (120) include a first coil pancake (1201) closest to the first end and a second coil pancake (1202) adjacent to the first coil pancake (1201). The number of turns of the first coil pancake (1201) is less than that of the second coil pancake (1202), and the radial thickness of the inner insulation part (110) at the first axial position where the first coil pancake (1201) is located is greater than the radial thickness of the inner insulation part (110) at the second axial position where the second coil pancake (1202) is located.

2. The foil winding applicable to voltage levels above 10 kV according to claim 1, characterized in that, The plurality of coil pancakes (120) are symmetrically distributed with respect to an axial center plane (S), which is a plane passing through the center in the axial direction of the inner insulation part (110) and perpendicular to the axial direction. Both ends in the axial direction of the inner insulation part (110) further include a second end opposite to the first end. The plurality of coil pancakes (120) include a third coil pancake (1203) closest to the second end and a fourth coil pancake (1204) adjacent to the third coil pancake (1203). The number of turns of the third coil pancake (1203) is less than that of the fourth coil pancake (1204), and the radial thickness of the inner insulation part (110) at the third axial position where the third coil pancake (1203) is located is greater than the radial thickness of the inner insulation part (110) at the fourth axial position where the fourth coil pancake (1204) is located.

3. The foil winding applicable to voltage levels above 10 kV according to claim 1, wherein For any one coil pancake and any other coil pancake among the plurality of coil pancakes (120): The sum of the radial thickness of the any one coil pancake and the radial thickness of the inner insulation part (110) at the axial position where the any one coil pancake is located is equal to the sum of the radial thickness of the any other coil pancake and the radial thickness of the inner insulation part (110) at the axial position where the any other coil pancake is located.

4. The foil winding applicable to voltage levels above 10 kV according to claim 1, wherein The foil winding (100) applicable to voltage levels above 10 kV further includes: An outer insulation part (130), which is arranged on the outer side in the radial direction of the plurality of coil pancakes (120) and surrounds the plurality of coil pancakes (120). For any one of the plurality of coil pancakes (120) and any other coil pancake: the sum of the radial thickness of the any one coil pancake, the radial thickness of the inner insulation part (110) at the axial position where the any one coil pancake is located, and the radial thickness of the outer insulation part (130) at the axial position where the any one coil pancake is located is equal to the sum of the radial thickness of the any other coil pancake, the radial thickness of the inner insulation part (110) at the axial position where the any other coil pancake is located, and the radial thickness of the outer insulation part (130) at the axial position where the any other coil pancake is located.

5. The foil winding applicable to voltage levels above 10 kV according to claim 4, characterized in that, From the center in the axial direction of the inner insulation part (110) towards both ends in the axial direction, the radial thickness of the outer insulation part (130) shows an increasing distribution.

6. The foil winding applicable to voltage levels above 10 kV according to claim 4, characterized in that, The centers of the plurality of coil pancakes (120) in the radial direction are located on a straight line.

7. The foil winding applicable to voltage levels above 10 kV according to claim 1, characterized in that, From the center in the axial direction of the inner insulation part (110) towards both ends in the axial direction, the number of turns of at least two adjacent coil pancakes is equal.

8. The foil winding applicable to voltage levels above 10 kV according to claim 1, wherein From the center in the axial direction of the inner insulation part (110) towards both ends in the axial direction, the number of turns of the coil pancakes shows a decreasing distribution.

9. The foil winding applicable to voltage levels above 10 kV according to claim 1, wherein From the center in the axial direction of the inner insulation part (110) towards both ends in the axial direction, the radial thickness of the inner insulation part (110) shows an increasing distribution.

10. A transformer, characterized in that, Comprising a foil winding (100) applicable to a voltage class above 10 kV according to any one of claims 1 to 9.

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