High-voltage winding and dry-type transformer

Abstract

Disclosed is a high-voltage winding (130), comprising a winding body (1310), a high-voltage coil (1320), a high-voltage insulating layer (1330), and an external insulating layer (1340). The winding body (1310) comprises a plurality of winding plates (1313, 2311, 1316); the plurality of winding plates (1313, 2311, 1316) are uniformly distributed in the circumferential direction of the winding body (1310); a wire is wound on the winding plates (1313, 2311, 1316) to form the high-voltage coil (1320); two ends of the wire form two external connections (D, X); the high-voltage insulating layer (1330) wraps the high-voltage coil (1320) and the winding body (1310); and the external insulating layer (1340) wraps the side walls of the external connections (D, X). Further disclosed is a dry-type transformer (10). The high-voltage winding (130) uses the external insulating layer (1340) to wrap the side walls of the external connections (D, X), thereby preventing the permeation of water vapor, ensuring the sealing effect, and effectively avoiding the problem of discharge of a wire outlet end.

Description

High voltage winding and dry-type transformer Technical Field

[0001] The present application relates to the field of dry-type transformer manufacturing, and more specifically to a high-voltage winding and a dry-type transformer. Background Art

[0002] The high-voltage windings of traditional silicone rubber dry-type transformers require the connection of outlet bushings, heat shrink tubing, and other structures to prevent discharge problems at the outlet. Outlet bushings typically use a conductive copper rod cast with an epoxy resin insulation layer, or a fiberglass tube reinforced with a conductive copper rod and then cast with a liquid silicone rubber shed. However, this structure cannot be integrally molded with the high-voltage winding insulation layer, requiring a sealed structure to be designed, which can lead to sealing failure. Heat shrink tubing typically uses materials such as PVC and PEC to encapsulate the outlets, but this also fails to achieve a complete seal. Rainwater seeping into the heat shrink tubing can corrode the conductor, affecting the product's insulation performance. Furthermore, all of the above structures require additional processing and overall assembly, resulting in a long processing cycle.

[0003] Summary of the Invention

[0004] In view of the deficiencies in the prior art, the purpose of the present application is to provide a high-voltage winding to solve the problem of sealing failure at the outlet end of the existing high-voltage winding.

[0005] To achieve the above-mentioned purpose, the technical means adopted in this application are as follows: a high-voltage winding, including a winding body, a high-voltage coil, a high-voltage insulation layer, and an external insulation layer. The winding body includes several winding plates, and the several winding plates are evenly distributed along the circumference of the winding body. The wire is wound on the winding plate to form a high-voltage coil, and two ends of the wire form two external connections. The high-voltage insulation layer wraps the high-voltage coil and the winding body, and the external insulation layer wraps the external side wall.

[0006] Preferably, the external connection is further connected to a central conductor, the central conductor is used to support the external connection, and the external connection insulation layer wraps the external connection and the central conductor.

[0007] Preferably, the external conductor and the central conductor are connected by welding.

[0008] Preferably, the external insulating layer includes a sheath and a plurality of sheds, the sheath is arranged on the outer periphery of the external connection, and the plurality of sheds are arranged at intervals on the outer periphery of the sheath.

[0009] Preferably, the winding plate is provided with a plurality of comb teeth, the high-voltage coil includes a plurality of coil segments, and at least one coil segment is provided between two adjacent comb teeth on the winding plate.

[0010] Preferably, the winding body further includes a plurality of auxiliary parts, which are annular and arranged at intervals along the axial direction of the high-voltage winding, and the auxiliary parts are connected to the winding plate by clamping.

[0011] Preferably, the winding plate is provided with a plurality of winding members movable along the winding plate, and a winding groove is formed between two adjacent winding members on the winding plate for winding the conductor.

[0012] Preferably, a movable groove is provided on the winding member, and the winding member and the winding plate are slidably connected through the movable groove.

[0013] Preferably, the winding plate is an I-shaped strip, the movable groove of the winding member is a T-shaped groove, and at least part of the winding plate is inserted into the movable groove so that the winding member can move along the winding plate.

[0014] Preferably, the external insulating layer and the high-voltage insulating layer are both made of high-temperature vulcanized silicone rubber.

[0015] Preferably, the external insulating layer and the high-voltage insulating layer are integrally injection-molded.

[0016] Preferably, the high-voltage winding further includes a semi-conductive shielding layer, which covers the outer peripheral surface of the high-voltage insulating layer.

[0017] Preferably, the semi-conductive shielding layer is a semi-conductive silicone rubber layer made by an injection process, or the semi-conductive shielding layer is a semi-conductive paint layer made by a spraying process.

[0018] Preferably, the outer surface of the high-voltage insulation layer is provided with a curved surface structure.

[0019] Preferably, a plurality of sheds or a plurality of arc-shaped protrusions are provided on the periphery of the high-voltage insulation layer, and the plurality of sheds or the plurality of arc-shaped protrusions are evenly spaced along the axial direction of the high-voltage winding to form a curved surface structure.

[0020] Preferably, an intermediate insulating layer is provided between the winding plate and the high-voltage coil. The intermediate insulating layer is an elastic insulator. The elastic insulator is a silicone rubber gasket, a high-temperature vulcanized silicone rubber layer, a liquid silicone rubber layer, or a room-temperature vulcanized silicone rubber layer.

[0021] Preferably, the intermediate insulating layer includes a first insulating layer and a second insulating layer, the first insulating layer covers the outer periphery of the winding plate, and the second insulating layer covers the outer periphery of the wire, so that the intermediate insulating layer is located between the winding body and the high-voltage coil, and the first insulating layer and the second insulating layer are liquid silicone rubber layers.

[0022] To achieve the above-mentioned purpose, another technical solution adopted in this application is as follows: a dry-type transformer, including an iron core, a low-voltage winding and the aforementioned high-voltage winding, the low-voltage winding is arranged outside the iron core, and the high-voltage winding is arranged outside the low-voltage winding.

[0023] The beneficial effect of the present application is that the high-voltage winding of the present application adopts an external insulating layer to wrap the external side wall, which can prevent water vapor penetration, ensure the sealing effect, and effectively avoid the discharge problem at the output end.

[0024] At the same time, the external insulation layer and the high-voltage insulation layer are injection molded as one, so that there is no interface caused by different materials between the high-voltage insulation layer and the external insulation layer, and the sealing is better. The one-piece molding process saves the time of preparing the external insulation layer separately, shortens the processing cycle, reduces labor costs and manufacturing energy consumption, and has lower overall costs.

[0025] In addition, by setting up umbrella skirts, the creepage distance is increased, which can avoid the insulation degradation problem caused by local discharge on the outer surface of the high-voltage winding during long-term operation, and effectively improve the pollution flashover resistance of the dry-type transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG1 is a front view of a dry-type transformer 10 according to an embodiment of the present application;

[0027] FIG2 is a top view of a dry-type transformer 10 according to an embodiment of the present application;

[0028] FIG3 is a front view of the assembled core 110 according to one embodiment of the present application;

[0029] FIG4 is an enlarged view of point G in FIG2 ;

[0030] FIG5 is a perspective schematic diagram of a winding body 1310 according to an embodiment of the present application;

[0031] FIG6 is a cross-sectional view of a support cylinder 1311 according to an embodiment of the present application;

[0032] FIG7 is a perspective schematic diagram of a high-voltage coil 1320 wound on a winding body 1310 according to an embodiment of the present application;

[0033] FIG8 is a perspective schematic diagram of a winding plate 1316 according to another embodiment of the present application;

[0034] FIG9 is an enlarged view of point L in FIG8 ;

[0035] FIG10 is a perspective schematic diagram of a high-voltage winding 130 according to an embodiment of the present application;

[0036] FIG11 is a schematic circuit diagram of a high-voltage coil 1320 according to an embodiment of the present application;

[0037] FIG12 is a perspective schematic diagram of a winding portion 2310 according to an embodiment of the present application;

[0038] FIG13 is a perspective schematic diagram of an auxiliary member 2312 according to an embodiment of the present application;

[0039] FIG14 is a perspective schematic diagram of a high-voltage winding 130 according to another embodiment of the present application;

[0040] FIG15 is another view of the high voltage winding 130 shown in FIG12;

[0041] FIG16 is a perspective schematic diagram of a tooling connector 101 according to an embodiment of the present application;

[0042] FIG17 is a schematic diagram of a curved surface structure provided on the outer surface of the high-voltage insulation layer 1330 according to an embodiment of the present application;

[0043] FIG18 is a cross-sectional view of the high-voltage winding 130 shown in FIG17 ;

[0044] FIG19 is a schematic diagram of another embodiment of the present application in which a curved surface structure is provided on the outer surface of the high-voltage insulation layer 1330;

[0045] FIG20 is a cross-sectional view of the high-voltage winding 130 shown in FIG19 . DETAILED DESCRIPTION

[0046] Upon request, specific embodiments of the present application will be disclosed herein. However, it should be understood that the embodiments disclosed herein are merely exemplary of the present application, which may be embodied in various forms. Therefore, the specific details disclosed herein are not to be construed as limiting, but merely as a basis for the claims and as a representative basis for teaching those skilled in the art to variously apply the present application in any appropriate manner in practice, including employing the various features disclosed herein in combination with features that may not be explicitly disclosed herein.

[0047] As shown in Figures 1-3, the dry-type transformer 10 is a three-phase transformer, with phases A, B, and C. That is, the dry-type transformer 10 includes three single-phase transformers 100. Depending on the structure of the iron core 110, the three transformers 100 can be arranged in a straight line or a triangular configuration, and the three transformers 100 are symmetrical. Furthermore, the dry-type transformer 10 can also be an isolation transformer, a variable frequency transformer, a test transformer, or the like.

[0048] In one embodiment, referring again to Figures 1-3, three transformers 100 are arranged to form a linear structure. The dry-type transformer 10 includes an iron core 110, three low-voltage windings 120, and three high-voltage windings 130. The iron core 110 includes three cylindrical iron core bodies 111, an upper iron yoke 112 located at the upper ends of the three cylindrical iron core bodies 111, and a lower iron yoke 113 located at the lower ends of the three cylindrical iron core bodies 111. The three low-voltage windings 120 are respectively sleeved on the outer peripheries of the three cylindrical iron core bodies 111, and the three high-voltage windings 130 are respectively sleeved on the outer peripheries of the three low-voltage windings 120. The cylindrical iron core body 111 is formed by stacking multiple layers of silicon steel sheets and fastened with cable ties. The radial cross-section of the cylindrical iron core body 111 is generally elliptical, circular, or other shapes, as long as it can be accommodated in the hollow cavity of the low-voltage winding 120. The upper iron yoke 112 and the lower iron yoke 113 are also formed by stacking multiple layers of silicon steel sheets, so that the three columnar iron core bodies 111 are fixedly connected.

[0049] Core clamps 140 are provided on the outside of the core 110 to hold the core 110 in place. These clamps 140 can be channel steel or hollow tubes. Four core clamps 140 are provided, with two symmetrically positioned on either side of the upper end of the core 110 and above the high-voltage winding 130. The other two core clamps 140 are symmetrically positioned on either side of the lower end of the core 110 and below the high-voltage winding 130.

[0050] As shown in Figures 2 and 4, the low-voltage winding 120 includes a copper foil 121, a low-voltage insulating layer 122 and a support bar 123. The copper foil 121 and the low-voltage insulating layer 122 are arranged alternately, that is, the copper foil 121 is formed by winding a whole sheet of copper foil, and the low-voltage insulating layer 122 and the copper foil 121 are overlapped and wound together.

[0051] At least one heat dissipation channel is provided in the low-voltage winding 120 , which is located between adjacent copper foils 121 and low-voltage insulation layers 122 , and a support bar 123 is located in the heat dissipation channel for supporting and isolating adjacent copper foils 121 and low-voltage insulation layers 122 .

[0052] The low-voltage insulation layer 122 is made of polyimide impregnated paper, that is, a soft composite material of polyimide film and polysulfone fiber non-woven fabric impregnated with diphenyl ether resin and then baked. Alternatively, other insulating materials such as DMD insulation paper or silicone rubber film can be used, depending on the different heat resistance grades of the dry-type transformer.

[0053] The insulating support bar 123 may be made of glass fiber or aramid fiber impregnated with epoxy resin, and the insulating support bar 123 may be a long bar with an I-shaped or square cross-section, etc., which is not limited here.

[0054] As shown in Figures 5 to 7, 10 and 11, the high-voltage winding 130 includes a winding body 1310, a high-voltage coil 1320 and a high-voltage insulation layer 1330. The wire is wound on the winding body 1310 to form the high-voltage coil 1320. The winding body 1310 includes a support cylinder 1311 and a winding portion 1312, wherein the support cylinder 1311 is a hollow cylinder, which can be a hollow cylinder, a hollow elliptical cylinder or other hollow cylindrical body; the winding portion 1312 is located on the outer circumference of the support cylinder 1311, and the wire is wound in the winding portion 1312 to form the high-voltage coil 1320, and the high-voltage coil 1320 includes a plurality of coil segments, which are arranged at intervals along the axial direction of the support cylinder 1311.

[0055] The winding portion 1312 includes a plurality of winding plates 1313, which are uniformly distributed circumferentially on the outer circumferential surface of the support tube 1311. Each winding plate 1313 is arranged axially along the support tube 1311, and the axial length of the winding plate 1313 along the support tube 1311 is less than the axial length of the support tube 1311 along its axial direction. The number of winding plates 1313 is at least two, that is, it can be two, three, four or more, without limitation. In order to make the wire winding secure and save materials as much as possible, the number of winding plates 1313 of the 10kV / 1000kVA dry-type transformer is set to twelve. In other embodiments, the axial length of the winding plate along the support tube can also be equal to the axial length of the support tube along its axial direction.

[0056] The winding plate 1313 is a rectangular plate, and the longer side of the winding plate 1313 is arranged along the axial direction of the support tube 1311. The winding plate 1313 is also provided with a plurality of winding grooves 1314. The plurality of winding grooves 1314 are arranged along the radial direction of the support tube 1311 and are distributed at intervals along the axial direction of the support tube 1311, so that the winding plate 1313 is comb-shaped. The height of the comb teeth on the winding plate 1313 along the axial direction of the support tube 1311 is defined as the tooth height. The tooth height of the comb teeth at both ends of the winding plate 1313 and the tooth height of the comb teeth in the middle of the winding plate 1313 are both greater than the tooth height of the comb teeth in other parts. This is because the field strength at the ends of the high-voltage coil 1320 is uneven. Setting the tooth height at both ends of the winding plate 1313 a little larger can make the electric field uniform. A tap of the tap line needs to be led out from the middle of the winding plate 1313. Setting the tooth height in the middle of the winding plate 1313 a little larger will increase the distance between the corresponding two adjacent winding slots 1314, leaving space for the tap led out from the middle of the winding plate 1313.

[0057] At least one coil section is set between two adjacent comb teeth on the winding plate 1313, so that a wire is wound in each winding slot 1314, the high-voltage coil 1320 is reasonably distributed, and each coil section is set at intervals.

[0058] Among them, when several winding plates 1313 are evenly distributed on the outer surface of the support tube 1311 in the circumferential direction, the two ends of all the winding plates 1313 are set flush, and the winding grooves 1314 on all the winding plates 1313 are matched one by one in the circumferential direction of the support tube 1311. Each coil is wound by a wire along the circumference of the support tube 1311 in a corresponding circle of winding grooves 1314 on all the winding plates 1313, with balanced force and good mechanical strength.

[0059] In other embodiments, the winding plate may also be an annular disk disposed circumferentially around the support tube. A plurality of winding plates are spaced apart along the axial direction of the support tube, and the wire is wound in a groove formed by two adjacent winding plates.

[0060] Among them, the support tube 1311 is a hollow tube formed of composite materials. The specific material and molding process can be adjusted according to the design requirements of the high-voltage winding and are not limited here.

[0061] The winding body 1310 can be formed by separately molding the support tube 1311 and the winding plate 1313 and then fixing them by bonding, or it can be integrally cast into a hollow tube at one time and then the support tube and the winding plate are formed by turning.

[0062] In an application scenario, in combination with Figures 5, 6 and 10, the winding body 1310 also includes two flanges 1315, which are located at the two ends of the support tube 1311 and extend radially outward along the support tube 1311 to form an annular disk surface. The flanges 1315 at both ends are arranged opposite to each other. When the winding plate 1313 is placed on the outer peripheral surface of the winding body 1310, the outer end surfaces of the two ends of the winding plate 1313 abut against the disk surfaces of the two flanges 1315 facing each other, thereby preventing the winding plate 1313 from being damaged due to the larger injection pressure during the injection process of the high-voltage insulation layer 1330.

[0063] In other embodiments, the support tube and the winding portion of the winding body may be connected by means of an auxiliary component, which is not limited here.

[0064] In another embodiment, in combination with Figures 12-13, the winding body may also only include the winding portion 2310, that is, the winding body omits the structure of the rigid insulating inner liner, so that the high-voltage winding has better thermal conductivity, eliminates the interface between the high-voltage insulation layer and the rigid insulating inner liner, thereby suppressing surface discharge of the rigid insulating inner liner, saving materials and reducing costs.

[0065] The winding portion 2310 includes a plurality of comb-shaped winding plates 2311 and a plurality of auxiliary parts 2312. The plurality of auxiliary parts 2312 are annular and arranged at intervals along the axial direction of the auxiliary parts 2312. The winding plates 2311 are fixed to the outer periphery of the plurality of auxiliary parts 2312 along the axial direction of the auxiliary parts 2312, so that the winding plates 2311 are connected to all auxiliary parts 2312 at the same time, and the plurality of winding plates 2311 are evenly distributed along the circumference of the auxiliary parts 2312. Among them, the axial direction of the auxiliary parts 2312 is the axial direction of the winding portion 2310, that is, the axial direction of the high-voltage winding. The auxiliary parts 2312 can be circular or elliptical, and can be designed according to the overall shape of the high-voltage winding. Several winding plates 2311 are arranged circumferentially, and a conductor is wound around the winding portion 2310 to form a high-voltage coil. The high-voltage coil comprises several coil segments, which are spaced apart along the axial direction of the high-voltage winding. A high-voltage insulation layer wraps around the high-voltage coil, several auxiliary components 2312, and the winding plates 2311. The auxiliary components 2312 maintain the stability of the winding plates 2311, preventing them from shifting or misaligning during the conductor winding process and the injection of the high-voltage insulation layer.

[0066] In one embodiment, a plurality of first card grooves 23121 are provided on the outer surface of the auxiliary part 2312, and the plurality of first card grooves 23121 are evenly arranged along the circumference of the auxiliary part 2312, and the side surfaces of the plurality of winding plates 2311 are respectively correspondingly arranged in the plurality of first card grooves 23121, so that the plurality of winding plates 2311 are evenly distributed circumferentially on the outer periphery of the plurality of auxiliary parts 2312; the two ends of all the winding plates 2311 are arranged flush, and the first card grooves 23121 on all the auxiliary parts 2312 are matched one by one in the axial direction of the auxiliary part 2312, so that each winding plate 2311 can be arranged along the axial direction of the auxiliary part 2312, and then the wire is wound in the comb teeth on the winding plate 2311 to form a high-voltage coil, that is, the plurality of sections of the high-voltage coil are spaced apart and distributed in the axial direction of the winding part 2310, with balanced force and good mechanical strength.

[0067] The width of the first slot 23121 along the circumferential direction of the auxiliary part 2312 is defined as the slot width of the first slot 23121. The slot width of the first slot 23121 matches the thickness of the winding plate 2311, so that the winding plate 2311 and the auxiliary part 2312 are firmly assembled, thereby avoiding the situation that when the slot width of the first slot 23121 is smaller than the thickness of the winding plate 2311, the winding plate 2311 is difficult to align and fix on the auxiliary part 2312, or when the slot width of the first slot 23121 is larger than the thickness of the winding plate 2311, the winding plate 2311 falls off from the outside of the auxiliary part 2312. The winding plate 2311 is fixedly connected to the first slot 23121 by an adhesive. The adhesive is a two-component high-temperature resistant epoxy glue. Of course, it can also be other adhesives, but it is necessary to ensure that the adhesive can make the winding plate 2311 and the auxiliary part 2312 firmly bonded, and the adhesive must be resistant to high temperatures to adapt to the high-voltage insulation layer using high-temperature injection to cover the winding plate 2311 and the auxiliary part 2312.

[0068] In other embodiments, a slot can be provided on the side of the winding plate near the auxiliary member, and the auxiliary member can be locked in the slot of the winding plate to securely connect the winding plate and the auxiliary member. Of course, it is preferred that the first slot 23121 is provided on the auxiliary member 2312 in the aforementioned embodiment to avoid weakening the mechanical strength of the winding plate due to the provision of the slot.

[0069] The structure of the winding plate 2311 is similar to that of the aforementioned winding plate 1313, except that flow grooves 23111 are provided at both ends of the winding plate 2311, so that during the injection molding process of the high-voltage insulation layer, the injected silicone rubber raw material can flow from the end of the winding part 2310 into the inner side of the winding part 2310, thereby allowing the high-voltage insulation layer to fully fill the gap between the winding part 2310 and the high-voltage coil and the two ends of the winding part 2310.

[0070] The winding plate 2311 and the auxiliary component 2312 are both made of glass fiber impregnated with epoxy resin. Multiple layers of glass fiber cloth impregnated with epoxy resin are stacked to a desired thickness and then molded and cured to form a fiberglass reinforced plastic component. The winding plate 2311 and the auxiliary component 2312 can be formed separately and then bonded together, or they can be integrally formed.

[0071] 5, 7, and 10, taking the A-phase transformer 100 as an example, a conductor is circumferentially wound around the outer circumference of the winding body 1310 to form a high-voltage coil 1320. The conductor is wound in the winding grooves 1314 of the winding portion 1312, so that the high-voltage coil 1320 is spaced apart in the axial direction of the support cylinder 1311. After winding, the conductor forms two external connections at the ends: a first external connection D and a second external connection X. The first external connection D is used to connect to a cable, and the second external connection X is used to connect to other external connections, such as those used to connect to each phase of the transformer in a three-phase transformer. The conductor leads to six taps in the middle of the winding body 1310 along its axial direction: tap 2, tap 3, tap 4, tap 5, tap 6, and tap 7. These six taps form a tap changer. For ease of description, taps 2, 4, and 6 are defined as the first tap changer, and taps 3, 5, and 7 are defined as the second tap changer.

[0072] In one application scenario, as shown in Figures 5, 7, 10, and 11, the conductor includes a first conductor and a second conductor. The first conductor and the second conductor are both continuous conductors, and are both coated with an insulating layer. The insulating layer can be a polyimide film or a glass fiber film, or other insulating materials such as polyester paint, or a combination of multiple insulating materials, which is not limited here. The first conductor is wound from one end of the winding portion 1312 along the axial direction of the winding body 1310 to the middle of the winding portion 1312, and three taps are drawn out. For the convenience of expression, the upper end of the winding portion 1312 is defined as the first end, and the lower end of the winding portion 1312 is defined as the second end. The first wire is wound from the first end of the winding portion 1312 to the second end of the winding portion 1312. The first wire is wound around the designed number of turns in the first winding slot 1314 corresponding to a circle on all winding plates 1313 to form a first section coil 1321. The first section coil 1321 is wound in a pancake-like manner, and only one pancake coil is set in each winding slot 1314. At this time, each section coil has only one pancake coil. The inner turn of the first conductor at the first end of the winding portion 1312 forms a first external connection D exposed outside the high-voltage insulation layer 1330. Specifically, the first external connection D is extended from the inner turn of the first coil segment 1321 (i.e., the head end of the first conductor). The outer turn of the first coil segment 1321 extends into the corresponding second winding slot 1314 on all winding plates 1313 to continue winding to form the second coil segment 1322. This continues in this manner until the first conductor reaches the middle of the winding body 1310. Three taps, namely, tap 6, tap 4, and tap 2, are respectively extended from the outer turn of the three coil segments, as shown in FIG11. Thus, the winding of the first conductor is completed.

[0073] The second conductor is wound from the middle of winding section 1312 along the axial direction of winding body 1310 to the second end of winding section 1312, leading to three more taps. The second conductor begins winding in the next winding slot 1314 adjacent to tap 2, forming a third coil segment 1323. The second conductor continues winding toward the second end of winding section 1312 in the same manner as the first conductor. Three more taps, namely, tap 3, tap 5, and tap 7, are led out of the three coil segments starting with third coil segment 1323, until the second conductor reaches the last winding slot 1314 of each winding plate 1313 at the second end of winding section 1312, forming a terminal coil segment 1324. The outer turn wire end of the second wire at the second end of the winding portion 1312 forms a second external connection X exposed outside the high-voltage insulation layer 1330, that is, the second external connection X is led out at the outer turn wire end of the terminal segment coil 1324 (that is, the end of the second wire), and the second wire is wound.

[0074] When winding the wire, it is wound in the corresponding winding grooves 1314 on all winding plates 1313, so that each coil formed by the winding wire is perpendicular to the axial direction of the winding body 1310. This facilitates winding and neatly arranges the wires. The winding plates 1313 are evenly stressed and have good mechanical strength. In other embodiments, other existing wire winding methods can also be used according to the design requirements of the high-voltage winding, and this is not limited here.

[0075] In another application scenario, in combination with Figures 8 and 9, in order to make the winding of the wire on the winding body more flexible and expand the scope of application of the winding body, the winding body can also adopt a movable comb structure, that is, the winding portion of the winding body includes a plurality of winding plates 1316 (only one winding plate 1316 is shown in the figure for illustration), and the plurality of winding plates 1316 are evenly distributed along the circumference of the winding body. The winding plate 1316 is provided with a plurality of winding members 1317 that are movable along the winding plate 1316. A winding groove is formed between two adjacent winding members 1317 on the winding plate 1316 for winding the wire. The plurality of winding grooves are arranged along the radial direction of the winding body and are spaced apart along the axial direction of the winding body, so that the winding plate 1316 and the winding member 1317 are combined to form a comb shape as a whole.

[0076] A movable groove 1318 is set at the bottom where the winding piece 1317 is connected to the winding plate 1316. The winding piece 1317 and the winding plate 1316 are slidingly connected through the movable groove 1318, so that the winding piece 1317 can move along the winding plate 1316, which is convenient for flexible adjustment of the position of the winding piece 1317 according to the shape and structure of the high-voltage coil, has a wider range of applications, and further reduces costs.

[0077] In this embodiment, the winding plate 1316 is a long strip with an I-shaped cross-section, and the winding member 1317 is a rectangular plate. The movable groove 1318 of the winding member 1317 is correspondingly configured as a T-slot, that is, at least a portion of the winding plate 1316 is inserted into the movable groove, so that the winding member 1317 can move along the winding plate 1316. In other embodiments, the cross-section of the winding plate can also be trapezoidal or other irregular polygonal, as long as the shape of the movable groove of the winding member is adjusted to match the winding plate, so that the winding member can move smoothly along the winding plate and is not easily dislodged.

[0078] The winding element 1317 is made of fiber-reinforced composite material, for example, glass fiber reinforced epoxy resin or aramid fiber reinforced epoxy resin composite material. The winding element 1317 can also be made of resin material, for example, epoxy resin material. This application does not impose any restrictions on this, as long as the strength of the winding element 1317 can be guaranteed.

[0079] As shown in Figure 10 , a high-voltage insulation layer 1330 wraps around the high-voltage coil 1320 and the winding body 1310 to form the high-voltage winding 130. The high-voltage insulation layer 1330 is made of high-temperature vulcanized silicone rubber. A wire is first wound around the winding body 1310 to form the high-voltage coil 1320. The winding body 1310 and the high-voltage coil 1320 serve as the injection molding body. The injection molding body is then placed into a mold in an injection molding machine. Silicone rubber raw material is then added, and high-temperature vulcanized silicone rubber is injection-molded around the entire periphery of the injection molding body to form the high-voltage winding 130. The use of high-temperature vulcanized silicone rubber in the high-voltage insulation layer 1330 improves the insulation and mechanical properties of the high-voltage winding 130 as a whole.

[0080] Among them, the high-temperature vulcanized silicone rubber of the present application adopts a high-temperature vulcanized silicone rubber material system, including raw rubber, reinforcing agent, flame retardant, heat-resistant agent and other auxiliary materials.

[0081] After the high-voltage coil 1320 and the winding body 1310 are covered with high-temperature vulcanized silicone rubber by overall vacuum injection, the high-temperature vulcanized silicone rubber fills the gap between the high-voltage coil 1320 and the winding body 1310 and wraps the two ends of the winding body 1310, and the high-temperature vulcanized silicone rubber does not cover the inner wall of the support tube 1311, so that the high-voltage winding 130 is a hollow column as a whole, which can be a hollow cylinder, a hollow elliptical cylinder, or other hollow cylindrical bodies.

[0082] Compared to the epoxy resin high-voltage insulation layer in the prior art, silicone rubber has the following advantages: 1) It has excellent fire resistance, low-temperature resistance, aging resistance, and short-circuit test resistance, which can extend the service life of the dry-type transformer 10; 2) The copper coil is easily peeled off the silicone rubber, and the material has a recyclability rate of over 99%, which is more environmentally friendly; 3) The silicone rubber elastomer can reduce the local discharge caused by mechanical vibration, which has an inhibitory effect on equipment discharge. The silicone rubber product under the action of discharge is non-conductive silica, which effectively inhibits further insulation degradation; 4) It can reduce the operating loss of the dry-type transformer 10, which is more energy-efficient; 5) It has better resistance to harsh environments and can be installed indoors and outdoors. Furthermore, the high-voltage insulation layer 1330 is integrally vulcanized and injection molded. This process method makes the high-voltage insulation layer 1330 more stable and has higher mechanical properties than the existing room temperature vulcanization method. It also has better adhesion to the high-voltage coil 1320 and winding body 1310, effectively extending the service life of the high-voltage insulation layer 1330. Furthermore, compared to liquid silicone rubber, the high-temperature vulcanized silicone rubber filler is evenly dispersed, and will not cause partial discharge in the dry-type transformer 10 due to filler agglomeration, thereby improving the overall performance of the dry-type transformer 10 .

[0083] Furthermore, in combination with FIG5 and FIG7 , in order to eliminate the solid interface problem between the high-voltage coil 1320 and the winding plate 1313 , an intermediate insulating layer (not shown) is provided between the winding plate 1313 and the high-voltage coil 1320 .

[0084] In one embodiment, an intermediate insulating layer is provided on the contact surface between the comb teeth of the winding plate 1313 and the high-voltage coil 1320, that is, the intermediate insulating layer is first provided in the winding groove 1314 of the winding plate 1313, and then the wire is wound, so that the intermediate insulating layer is located between the comb teeth of the winding plate 1313 and the high-voltage coil 1320, avoiding the local discharge problem caused by the solid interface generated by direct contact between the two, thereby improving the insulation performance of the high-voltage winding 130.

[0085] In this embodiment, the middle insulating layer is an elastic insulator, which can effectively fill the gap between the wire and the comb teeth of the winding plate 1313 to ensure insulation effect.

[0086] Preferably, the elastic insulator is made of the same insulating material as the high-voltage insulation layer 1330, that is, the elastic insulator is made of silicone rubber. Silicone rubber can reduce mechanical vibration, reduce noise, prevent interface separation between the winding body and the wire, and avoid local discharge problems caused by interface separation between different materials. For example, the elastic insulator can be a silicone rubber gasket, the size of which is consistent with the size of the winding groove 1314 to fit the side wall and groove bottom of the winding groove 1314; it can also be an integrated or disconnected silicone rubber gasket, which is set in each corresponding circle of winding groove 1314 on all winding plates 1313. For another example, the elastic insulator can also be a high-temperature vulcanized silicone rubber layer or a liquid silicone rubber layer or a room-temperature vulcanized silicone rubber layer, that is, a silicone rubber layer is first formed on the surface of the winding plate 1313, and then the wire is wound. In other embodiments, the structure and material of the intermediate insulating layer can be adjusted according to the design requirements of the high-voltage winding, and are not limited here.

[0087] In another embodiment, the intermediate insulating layer covers the outer periphery of the wire, that is, the intermediate insulating layer is first covered on the outer periphery of the wire, and then the wire is wound between the comb teeth of the winding plate 1313, and then the intermediate insulating layer is located between the comb teeth of the winding plate 1313 and the high-voltage coil 1320. The intermediate insulating layer can be a liquid silicone rubber layer, that is, a liquid silicone rubber layer is formed on the surface of the wire by spraying or dipping process, and then the wire is wound.

[0088] In another embodiment, an intermediate insulating layer is provided on both the surface of the winding plate 1313 and the surface of the conductor. The intermediate insulating layer includes a first insulating layer and a second insulating layer. The first insulating layer covers the outer periphery of the winding plate 1313, and the second insulating layer covers the outer periphery of the conductor. Positioning the intermediate insulating layer between the winding body 1310 and the high-voltage coil 1320 further prevents partial discharge caused by a solid interface between the coil and the winding plate 1313.

[0089] In this embodiment, both the first and second insulating layers are liquid silicone rubber layers, formed as described above. Liquid silicone rubber has good fluidity, remaining in a liquid state during spraying or dipping and naturally solidifying over time. Compared to solid silicone rubber, it can better cover the surface of the wires and winding plate 1313, thereby improving insulation. In other embodiments, the first and second insulating layers can be made of different materials without limitation.

[0090] Furthermore, in combination with Figures 14-15, the high-voltage winding 130 includes an external insulating layer 1340, which respectively wraps the two external side walls, that is, the external insulating layer 1340 respectively wraps the side walls of the first external D and the second external X, which can prevent water vapor penetration, ensure the sealing effect, and effectively avoid the discharge problem at the output end.

[0091] The external insulating layer 1340 includes a sheath 1341 and a plurality of sheds 1342 . The sheath 1341 is arranged on the outer periphery of the outer connection, that is, the sheath 1341 is respectively arranged on the periphery of the first outer connection D and the second outer connection X, and the plurality of sheds 1342 are arranged at intervals on the periphery of the sheath 1341 .

[0092] In this embodiment, the sheds 1342 are of equal size, meaning that all sheds 1342 extend outward from the external outer surface by the same length. By providing multiple sheds 1342, the creepage distance of the outer surface of the high-voltage winding 130 is increased, thereby preventing insulation degradation caused by partial discharge on the outer surface of the high-voltage winding 130 during long-term operation. This effectively improves the pollution flashover resistance of the dry-type transformer 10 and ensures its smooth and safe operation.

[0093] In other embodiments, the size and shape of the sheds can be adjusted according to the design requirements of the high-voltage winding. For example, the sheds can be designed in an alternating pattern of large and small sheds, that is, the sheds include a plurality of small sheds and a plurality of large sheds, the extension length of the small sheds from the circumscribed outer surface is less than the extension length of the large sheds from the circumscribed outer surface, the plurality of small sheds and the plurality of large sheds can be alternately arranged along the circumscribed axial direction, and the specific arrangement order and spacing of the large and small sheds can be adjusted according to the design requirements of the high-voltage winding. The structure of the alternating design of large and small sheds has good self-cleaning properties and is suitable for areas with relatively severe pollution.

[0094] The first external connection D and the second external connection X are each connected to a central conductor (not shown) that supports the external connection. The external insulating layer 1340 surrounds the central conductor. The central conductor supports the first external connection D and the second external connection X, preventing deformation of the first external connection D and the second external connection X during the molding process of the external insulating layer 1340, which could result in the external insulating layer 1340 not being able to fully surround the first external connection D and the second external connection X.

[0095] In this embodiment, the central conductor is made of metal, and the external connection and the central conductor are welded to ensure connection strength. The central conductor can be a solid rod or a hollow tube, as long as it can support and secure the external connection. Furthermore, the central conductor protrudes a certain distance outward from the outer surface of the high-voltage insulation layer 1330. The provision of the external insulation layer 1340 further increases the arc distance, effectively improving the lightning protection capability of the dry-type transformer 10.

[0096] The external insulating layer 1340 is made of high-temperature vulcanized silicone rubber. The advantages of high-temperature vulcanized silicone rubber are as mentioned above and will not be repeated here.

[0097] The external insulating layer 1340 and the high-voltage insulating layer 1330 are integrally injection molded, so that there is no interface caused by different materials between the high-voltage insulating layer 1330 and the external insulating layer 1340, and there is no problem of water vapor penetration, etc., and the sealing is better. In addition, the integral molding process eliminates the time of separately preparing the external insulating layer 1340, shortens the processing cycle, reduces labor costs and manufacturing energy consumption, and lowers the overall cost. In other embodiments, the high-voltage insulating layer can be injection molded first, and then the external insulating layer can be injection molded on the outer periphery of the external connection; alternatively, the external insulating layer and the high-voltage insulating layer can also be injection molded separately, and then the external insulating layer can be sleeved and fixed on the outer periphery of the external connection. This is not limited here.

[0098] As shown in Figure 14, before the high-temperature vulcanized silicone rubber is injected as a whole, a tooling connector 101 is set on each high-voltage coil 1320. Six stepped holes 1011 are provided on the plate surface, which are used to connect six taps respectively to prevent the six taps from being covered by the silicone rubber during the injection process and unable to be used for wiring.

[0099] In another application scenario, in combination with FIG10 , in order to reduce the electromagnetic interference of the dry-type transformer 10 on the external environment and the electrostatic effect of the high-voltage winding 130, the high-voltage winding 130 of the present application also includes a semi-conductive shielding layer (not shown), and the semi-conductive shielding layer covers the outer peripheral surface of the high-voltage insulation layer 1330, which can reduce the electromagnetic interference of the dry-type transformer 10 on the external environment and the electrostatic effect of the high-voltage winding, and the thermal effect generated by the induced current inside the semi-conductive shielding layer can keep the surface of the high-voltage winding 130 dry in salt spray and dirty and wet environments, thereby reducing safety risks. At the same time, due to the low conductivity of the semi-conductive shielding layer, the above-mentioned induced current is small, and the corresponding energy loss is also small. When the semi-conductive shielding layer is grounded and shielded, due to its low conductivity, the potential will not directly become 0, thereby causing the potential of the high-voltage coil 1320, the semi-conductive shielding layer, and the earth to show a gradient downward trend, thereby avoiding electrical safety risks caused by sudden potential drops.

[0100] In this embodiment, the semi-conductive shielding layer is a semi-conductive silicone rubber layer, which is made of a semi-conductive silicone rubber material through an injection process. That is, the semi-conductive silicone rubber material is injected into the entire periphery of the high-voltage insulation layer 1330 to form a semi-conductive shielding layer. The semi-conductive silicone rubber material includes a silicone rubber material, a conductive filler, a semi-conductive filler, a reinforcing filler, a thermally conductive filler, and a flame-retardant filler. That is, before injection, the conductive filler, the semi-conductive filler, the reinforcing filler, the thermally conductive filler, and the flame-retardant filler are respectively added to the silicone rubber material and mixed to form a semi-conductive silicone rubber material for the subsequent injection of the semi-conductive shielding layer. The conductive filler is aluminum or silver oxide or a mixture of the two. The semi-conductive filler is one or more of carbon black, acetylene ink, graphene, silicon carbide, and beryllium nitride. The reinforcing filler is white carbon black, the thermally conductive filler is aluminum oxide, and the flame-retardant filler is aluminum hydroxide. In other embodiments, the types and proportions of the components in the semi-conductive silicone rubber material can also be adjusted according to the shielding requirements of the high-voltage winding, and are not limited here.

[0101] The thickness of the semi-conductive shielding layer is 2 to 5 mm, which can ensure the shielding effect without affecting the heat dissipation performance of the high-voltage winding 130 .

[0102] Compared with traditional conductive coatings, the semi-conductive shielding layer of the present application has the following advantages: 1) The semi-conductive silicone rubber material of the semi-conductive shielding layer and the high-temperature vulcanized silicone rubber material of the high-voltage insulation layer 1330 both use silicone rubber material as the main matrix, and are both molded using a high-temperature vulcanization injection process, so that the semi-conductive shielding layer and the high-voltage insulation layer 1330 not only have a physical bonding effect, but also a chemical bonding effect of molecular chain cross-linking, the interface compatibility between the two is better, and the difference in electrical conductivity between the two is small, which can reduce the heat generation caused by the interface current; 2) The semi-conductive shielding layer prepared from the semi-conductive silicone rubber material has high mechanical strength and is an elastomer, and is not easily damaged by collision during operation and maintenance; 3) The semi-conductive shielding layer is molded in one step through an injection process, which is easy to operate and has high production efficiency. In addition, the manufacturing process does not require the use of volatile substances and does not produce chemicals. 4) The electrical conductivity of the semi-conductive silicone rubber material is between that of the conductive material and the silicone rubber material, so that the induced current inside the semi-conductive shielding layer is small during operation, and the energy loss generated is also small; 5) The semi-conductive shielding layer prepared by the semi-conductive silicone rubber material has the characteristic of autonomously adjusting the electrical conductivity. The electrical conductivity increases in a high electric field environment and decreases in a low electric field environment, which can effectively optimize the electric field distribution of the high-voltage winding; 6) The semi-conductive silicone rubber material also has the hydrophobicity and hydrophobic migration of the silicone rubber material, which can produce a lotus effect on the surface of the high-voltage winding 130, and it is not easy to form a water film and discharge. Even if the surface of the high-voltage winding 130 is contaminated, the small molecular substances in the semi-conductive shielding layer can also migrate to the contamination layer, so that the contamination layer also produces hydrophobicity, thereby improving the electrical safety of the high-voltage winding 130.

[0103] In other embodiments, the semiconductive shielding layer may also be a semiconductive paint layer, which is made by a spraying process using a semiconductive paint. The semiconductive paint may be made of existing materials or the formula may be adjusted according to the shielding requirements of the high-voltage winding, which is not limited here.

[0104] In another application scenario, in combination with Figures 17 to 20, in order to further reduce the problem of local discharge that is prone to occur during long-term use of the high-voltage winding 130, the outer surface of the high-voltage insulation layer 1330 of the high-voltage winding 130 of the present application is provided with a curved surface structure (for the sake of ease of expression, the external connection and related structures are not shown in the figure), which can increase the creepage distance of the outer surface of the high-voltage winding 130 and make the product more beautiful.

[0105] In one embodiment, as shown in Figures 17 and 18 , a plurality of sheds 1331 are disposed on the periphery of the high-voltage insulation layer 1330. These sheds 1331 are evenly spaced along the axial direction of the high-voltage winding 130 to form a curved structure. Each shed 1331 extends outward from the outer surface of the high-voltage insulation layer 1330 along the circumference of the high-voltage insulation layer 1330 to form an elliptical disc shape. The thickness of the shed 1331 at the edge distal from the high-voltage insulation layer 1330 is less than the thickness at the base proximal to the high-voltage insulation layer 1330. Sheds 1331 are not disposed at the top or bottom of the high-voltage insulation layer 1330 to avoid interfering with the subsequent assembly of the dry-type transformer 10.

[0106] In this embodiment, the specific arrangement and purpose of the plurality of umbrella skirts 1331 are similar to those of the aforementioned umbrella skirt 1342 and will not be described in detail here.

[0107] In another embodiment, as shown in conjunction with Figures 19 and 20 , a plurality of arcuate protrusions 1332 are provided on the outer circumference of the high-voltage insulation layer 1330. These arcuate protrusions 1332 are evenly spaced along the axial direction of the high-voltage winding 130 to form a curved surface structure. Each arcuate protrusion 1332 is arranged along the circumference of the high-voltage insulation layer 1330 and extends outward from the outer circumference of the high-voltage insulation layer 1330 to form an annular structure. The maximum distance that an arcuate protrusion 1332 extends outward from the outer circumference of the high-voltage insulation layer 1330 is defined as the protrusion height. The protrusion heights of each arcuate protrusion 1332 are equal. The arcuate protrusions 1332 are arranged continuously to form a corrugated shape with uniform distribution and smooth transitions. No arcuate protrusions 1332 are provided at the top and bottom of the high-voltage insulation layer 1330 to avoid affecting the subsequent assembly of the dry-type transformer 10.

[0108] The provision of a plurality of arc-shaped protrusions 1332 on the outer circumference of the high-voltage insulation layer 1330 increases the creepage distance of the outer surface of the high-voltage insulation layer 1330, effectively preventing insulation degradation caused by localized discharge on the outer surface of the high-voltage insulation layer 1330 during long-term operation of the high-voltage winding 130. Furthermore, the provision of a plurality of arc-shaped protrusions 1332 increases the surface area of ​​the high-voltage insulation layer 1330, facilitating heat dissipation from the high-voltage winding 130. Furthermore, since the various components of the dry-type transformer 10 are made of different materials and have inconsistent shrinkage rates, the outer surface of the high-voltage insulation layer 1330 after molding can easily become uneven. The provision of a plurality of evenly distributed arc-shaped protrusions 1332 with smooth transitions improves the appearance of the high-voltage insulation layer 1330, making the dry-type transformer 10 more aesthetically pleasing.

[0109] In this embodiment, both the high-voltage insulation layer 1330 and the curved surface structure are integrally molded using high-temperature vulcanized silicone rubber through integral injection molding. This avoids interface issues caused by the different materials of the high-voltage insulation layer 1330 and the curved surface structure, thereby improving the overall insulation and mechanical properties of the high-voltage winding 130. The specific molding method is as described above, and the shape and size of the mold can be adjusted accordingly to the curved surface structure, and will not be further described.

[0110] In other embodiments, the high-voltage insulation layer and the curved surface structure can also be integrally molded using liquid silicone rubber through a casting process, which is simple to operate and highly efficient, and can also avoid interface problems caused by different materials of the high-voltage insulation layer and the curved surface structure, thereby improving the insulation and mechanical properties of the high-voltage winding as a whole; or other types of silicone rubber materials can also be used, and the specific molding method can be adjusted according to the material properties and high-voltage winding design requirements, and is not limited here.

[0111] The technical content and features of this application have been disclosed above. However, it is understood that, based on the creative ideas of this application, those skilled in the art may make various changes and improvements to the above-mentioned structures and materials, including combinations of the technical features disclosed or claimed herein, and obviously including other combinations of these features. Such variations and / or combinations fall within the technical field involved in this application and fall within the scope of protection of the claims of this application.

Claims

1. A high voltage winding, characterized in that: The high-voltage winding includes a winding body, a high-voltage coil, a high-voltage insulation layer, and an external insulation layer. The winding body includes a plurality of winding plates, and the plurality of winding plates are evenly distributed along the circumference of the winding body. The wire is wound on the winding plate to form the high-voltage coil, and two ends of the wire form two external connections. The high-voltage insulation layer wraps the high-voltage coil and the winding body, and the external insulation layer wraps the side wall of the external connection.

2. The high voltage winding according to claim 1, characterized in that: The external connection is also connected to a central conductor, and the central conductor is used to support the external connection. The external connection insulation layer wraps the external connection and the central conductor.

3. The high voltage winding according to claim 2, characterized in that: The external connection is connected to the central conductor by welding.

4. The high voltage winding according to claim 1, characterized in that: The external insulating layer comprises a sheath and a plurality of sheds, wherein the sheath is arranged at the outer periphery of the external layer, and the plurality of sheds are arranged at intervals at the outer periphery of the sheath.

5. The high voltage winding according to claim 4, characterized in that: The winding board is provided with a plurality of comb teeth, the high voltage coil comprises a plurality of coil segments, and at least one coil segment is arranged between two adjacent comb teeth on the winding board.

6. The high voltage winding according to claim 1, characterized in that: The winding body also includes a plurality of auxiliary parts, which are annular and arranged at intervals along the axial direction of the high-voltage winding. The auxiliary parts are clamped and connected to the winding board.

7. The high voltage winding according to claim 1, characterized in that: The winding board is provided with a plurality of winding members movable along the winding board, and a winding groove is formed between two adjacent winding members on the winding board for winding the conducting wire.

8. The high voltage winding according to claim 7, characterized in that: The winding member is provided with a movable groove, and the winding member and the winding plate are slidably connected through the movable groove.

9. The high voltage winding according to claim 8, characterized in that: The winding plate is an I-shaped strip, the moving groove of the winding member is a T-shaped groove, and at least a portion of the winding plate is inserted into the moving groove so that the winding member can move along the winding plate.

10. The high voltage winding according to claim 1, characterized in that: The external insulating layer and the high-voltage insulating layer are both made of high-temperature vulcanized silicone rubber.

11. The high voltage winding according to claim 1, characterized in that: The external insulating layer and the high-voltage insulating layer are integrally injection-molded.

12. The high voltage winding according to claim 1, characterized in that: The high-voltage winding also includes a semi-conductive shielding layer, and the semi-conductive shielding layer covers the outer peripheral surface of the high-voltage insulating layer.

13. The high voltage winding according to claim 12, characterized in that: The semi-conductive shielding layer is a semi-conductive silicone rubber layer made by an injection process, or the semi-conductive shielding layer is a semi-conductive paint layer made by a spraying process.

14. The high voltage winding according to claim 1, characterized in that: The outer surface of the high-voltage insulation layer is provided with a curved surface structure.

15. The high voltage winding according to claim 14, characterized in that: A plurality of umbrella skirts or a plurality of arc-shaped protrusions are arranged on the periphery of the high-voltage insulation layer, and the plurality of umbrella skirts or the plurality of arc-shaped protrusions are evenly spaced along the axial direction of the high-voltage winding to form the curved surface structure.

16. The high voltage winding according to claim 1, characterized in that: An intermediate insulating layer is provided between the winding plate and the high-voltage coil. The intermediate insulating layer is an elastic insulator. The elastic insulator is a silicone rubber gasket, a high-temperature vulcanized silicone rubber layer, a liquid silicone rubber layer, or a room-temperature vulcanized silicone rubber layer.

17. The high voltage winding according to claim 16, characterized in that: The intermediate insulating layer includes a first insulating layer and a second insulating layer, the first insulating layer covers the outer circumference of the winding board, and the second insulating layer covers the outer circumference of the wire, so that the intermediate insulating layer is located between the winding body and the high-voltage coil, and the first insulating layer and the second insulating layer are liquid silicone rubber layers.

18. A dry-type transformer, characterized in that: It comprises an iron core, a low voltage winding and a high voltage winding as described in any one of claims 1 to 17, wherein the low voltage winding is sleeved outside the iron core, and the high voltage winding is sleeved outside the low voltage winding.

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