High-voltage winding, mold assembly, and manufacturing method for high-voltage winding

Abstract

The present application discloses a high-voltage winding, comprising a winding body, a high-voltage coil, and a high-voltage insulating layer, wherein the winding body comprises a plurality of winding plates and a plurality of fixing rings, the winding plates are connected to the fixing rings by means of a snap fit, and the fixing rings are provided with a plurality of first mounting holes and a plurality of second mounting holes for air duct members to pass through; a wire is wound on the winding body to form a high-voltage coil, the high-voltage coil comprises a plurality of pancake coils, and the high-voltage insulating layer wraps the high-voltage coil and the winding body; the high-voltage winding further comprises a plurality of air ducts, and the air ducts are arranged along the axial direction of the high-voltage winding and pass through the high-voltage insulating layer. The high-voltage winding of the present application is a high-voltage encapsulated pancake winding, in which axial air ducts are arranged, such that the high-voltage winding can dissipate heat by means of the inner and outer surfaces thereof and the axial air ducts therein, achieving higher heat dissipation efficiency; thus, the high-voltage winding can be applied to large-capacity dry type transformers having higher heat dissipation requirements, offering broader applicability and lower cost. The present application also discloses a mold assembly and a manufacturing method for the high-voltage winding.

Description

A high-voltage winding, a mold assembly, and a method for manufacturing the high-voltage winding.

[0001] Cross-references to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411886914.2, filed on December 20, 2024, entitled "A High Voltage Winding, Mold Assembly and Method for Manufacturing High Voltage Winding", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of power transformer technology, and in particular to a high-voltage winding, a mold assembly, and a method for manufacturing the high-voltage winding. Background Technology

[0004] In dry-type transformers, the high-voltage enclosed windings typically only have inner and outer surfaces as heat dissipation areas, resulting in low heat dissipation efficiency. This makes the high-voltage windings prone to overheating during operation, affecting their performance stability and lifespan. Currently, the common method to improve the heat dissipation performance of high-voltage windings is to incorporate internal cooling air channels. High-voltage windings can generally be divided into two main categories based on their coil structure: layered windings and disc windings.

[0005] Among them, the layered winding adopts the segmented winding method, and its air channel setting technology is relatively mature. That is, firstly, the wires are wound at several preset positions on the winding body according to a predetermined number of turns and then cut to obtain several coil segments. The predetermined number of turns is less than the full number of turns. Then, several air channel rods are placed at intervals along the axial direction on the outer periphery of each coil segment. Then, the wires of each coil segment are wound to the full number of turns on the outer periphery of the air channel rods in the same way as above. The wires of each coil segment located on the inner and outer sides of the air channel rods are welded to obtain the high voltage coil. Finally, after the high voltage insulation layer is formed, the air channel rods are pulled out to form a heat dissipation air channel.

[0006] Disc-shaped windings typically employ a continuous winding method. After one disc of coils is wound to its full turn count, the conductor is not cut, and the winding continues until all coils are completed. Since disc-shaped windings have far more wire segments than layered windings, if the above method is used to create heat dissipation channels, the conductors on both the inner and outer sides of the channel bar for each disc must be welded, significantly reducing welding reliability. Furthermore, the gaps between adjacent discs are small, making conductor welding difficult. Therefore, disc-shaped windings are difficult to dissipate heat through air channels. Currently, existing disc-shaped windings typically use increased cross-sectional area of ​​the high-voltage coil conductors to reduce conductor current density, thereby reducing resistance loss and heat generation. However, this method requires more conductors, increasing material costs; and the larger cross-sectional area of ​​the high-voltage coil leads to a larger dry-type transformer, further increasing overall material costs. Summary of the Invention

[0007] In view of the shortcomings of the prior art, one of the main objectives of this application is to provide a high-voltage winding with an internal axial air passage, which can improve heat dissipation efficiency and ensure the safety and reliability of the high-voltage winding operation.

[0008] To solve the above-mentioned technical problems, the technical solution adopted in this application is: a high-voltage winding, including a winding body, a high-voltage coil, and a high-voltage insulation layer. The winding body includes several winding plates and several fixing rings. The winding plates and fixing rings are snapped together. The fixing rings are provided with several first mounting holes and several second mounting holes. The first mounting holes and second mounting holes are used to cooperate in inserting air passage components. The conductors are wound on the winding body to form a high-voltage coil. The high-voltage coil includes several coil discs. The high-voltage insulation layer wraps around the high-voltage coil and the winding body. The high-voltage winding also includes several air passages. The air passages are arranged along the axial direction of the high-voltage winding and penetrate the high-voltage insulation layer.

[0009] In one embodiment, the winding plate is provided with a plurality of winding slots, and the plurality of winding plates are evenly distributed along the circumference of the high voltage winding. At least one coil is provided in each winding slot on the winding plate.

[0010] In one embodiment, the plurality of fixing rings includes two first fixing rings, and the plurality of winding plates are provided with two first slots respectively. The two first fixing rings are secured to both ends of the winding plate through the first slots, and a plurality of first mounting holes are provided between each pair of first slots.

[0011] In one embodiment, the plurality of fixing rings includes at least one second fixing ring, and the plurality of winding plates are provided with at least one fifth slot. The second fixing ring is secured in the middle of the winding plate through the fifth slot, and a plurality of second mounting holes are provided between every two fifth slots.

[0012] In one embodiment, the first mounting hole and the second mounting hole are identical in shape and number, and the first mounting hole and the second mounting hole are provided correspondingly.

[0013] In one embodiment, the cross-section of the air passage component is capsule-shaped or rounded trapezoidal, and the shape and size of the first mounting hole and the second mounting hole correspond to and match the cross-section of the air passage component; the outer diameter of one end of the air passage component gradually decreases along the axial direction away from the air passage component.

[0014] In one embodiment, the high-voltage coil is provided with at least two layers of insulating support material for clamping the air passage component. The insulating support material is fiberglass mesh, electrical composite material, or silicone cloth.

[0015] In one embodiment, a lubricating layer is provided on the outer periphery of the air passage component, and the lubricating layer is made of a release agent.

[0016] The second objective of this application is to provide a mold assembly, including a core mold, two mandrels, several fixing plates, and several air passage components. The two mandrels are fixedly connected to both ends of the core mold along the axial direction of the core mold. Several fixing plates are connected to one of the mandrels. The fixing plates are provided with through holes and several third mounting holes. The through holes are used to pass through the mandrels, and the third mounting holes are used to cooperate with the winding body to pass through the air passage components.

[0017] The third objective of this application is to provide a method for manufacturing a high-voltage winding, comprising the following steps:

[0018] Step 1: Assemble the mold assembly and the winding body, and place the winding body onto the mold assembly;

[0019] Step 2: Wind the wire onto the winding body to form a high-voltage coil. During the winding process of each coil, after the wire has been wound to the first preset number of turns, insert the air passage component along the axial direction of the winding body to the preset position, and then wind the wire to the second preset number of turns.

[0020] Step 3: Place the winding body with the high-voltage coil as the injection body into the injection machine, and inject silicone rubber into the entire periphery of the injection body to form a high-voltage insulation layer; or, place the winding body with the high-voltage coil as the casting body into the casting equipment, and cast silicone rubber into the periphery of the casting body to form a high-voltage insulation layer.

[0021] Step 4: Pull out the air passage component to obtain the high-voltage winding with an axial air passage.

[0022] The beneficial effects of this application are as follows: Compared with the prior art, the high-voltage encapsulated disc winding of this application has an axial air passage inside, which allows the high-voltage winding to dissipate heat through its inner surface, outer surface and internal axial air passage, resulting in higher heat dissipation efficiency. This structure can be applied to large-capacity dry-type transformers with higher heat dissipation requirements, thus expanding its application range. Moreover, compared with the heat dissipation method of increasing the cross-sectional area of ​​the high-voltage coil conductor, reducing resistance loss and increasing the surface area, the amount of conductor used is reduced, thus lowering the product cost.

[0023] Meanwhile, the winding body of this application adopts a fixed ring to hold the winding plate and install air passage components, which has a simple and stable structure and can avoid the winding plate and air passage components from moving or misaligning during the wire winding process and the high voltage insulation layer injection process, thus affecting the quality of the high voltage winding.

[0024] In addition, the wires in contact with both sides of the air passage are covered with insulating support material, so that after the air passage is pulled out to form an air passage, the wires inside the air passage will not be exposed to the air, which helps to extend the service life of the high voltage winding. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0026] Figure 1 is a front view of a dry-type transformer 10 according to an embodiment of this application;

[0027] Figure 2 is a top view of a dry-type transformer 10 according to an embodiment of this application;

[0028] Figure 3 is a front view of the assembled iron core 110 according to one embodiment of this application;

[0029] Figure 4 is an enlarged view of point G in Figure 2;

[0030] Figure 5 is a perspective view of the high-voltage winding 130 according to an embodiment of this application;

[0031] Figure 6 is a perspective view of a high-voltage coil 1320 wound on a winding body 1310 according to an embodiment of this application.

[0032] Figure 7 is a perspective view of the winding plate 1311 according to an embodiment of this application;

[0033] Figure 8 is a simplified circuit diagram of the high-voltage coil 1320 according to an embodiment of this application;

[0034] Figure 9 is a perspective view of the winding body 1310 according to an embodiment of this application;

[0035] Figure 10 is a perspective view of the first fixing ring 1410 according to an embodiment of this application;

[0036] Figure 11 is a perspective view of the second fixing ring 1420 according to an embodiment of this application;

[0037] Figure 12 is a perspective view of a winding body 1310 sleeved on a mold assembly 200 according to an embodiment of this application.

[0038] Figure 13 is a perspective view of the fixing plate 230 according to an embodiment of this application;

[0039] Figure 14 is a schematic diagram of the first disc coil wound with wire according to an embodiment of this application. Detailed Implementation

[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0041] As shown in Figures 1-3, the dry-type transformer 10 is a three-phase transformer, consisting of phase A, phase B, and phase C, meaning it comprises three single-phase transformers 100. Depending on the structure of the core 110, the three transformers 100 can be arranged in a linear or triangular configuration, and they are symmetrical. This dry-type transformer 10 can be used as an isolation transformer, frequency converter, or test transformer, etc.

[0042] In one embodiment, referring further to Figures 1-3, three transformers 100 are arranged in a linear structure. The dry-type transformer 10 includes a core 110, three low-voltage windings 120, and three high-voltage windings 130. The core 110, low-voltage windings 120, and high-voltage windings 130 are arranged sequentially from the inside to the outside. The core 110 includes three columnar core bodies 111, an upper yoke 112 located at the upper end of the three columnar core bodies 111, and a lower yoke 113 located at the lower end of the three columnar core bodies 111. The three low-voltage windings 120 are respectively sleeved on the outer periphery of the three columnar core bodies 111, and the three high-voltage windings 130 are respectively sleeved on the outer periphery of the three low-voltage windings 120. The columnar core bodies 111 are made of multiple layers of silicon steel sheets. The radial cross-section of the columnar core bodies 111 is approximately elliptical, circular, or other shapes, as long as they can be accommodated in the hollow cavity of the low-voltage windings 120. The upper yoke 112 and the lower yoke 113 are also made of multiple layers of silicon steel sheets, which fix the three columnar iron cores 111 together to form the iron core 110.

[0043] A core clamp 140 is provided on the outer side of the core 110. The core clamp 140 can be a channel steel piece or a hollow tube. The clamp located in the middle position is set close to the core 110, while the other two clamps are set in a direction away from the core 110.

[0044] Referring to Figures 2 and 4, the low-voltage winding 120 includes copper foil 121, a low-voltage insulation layer 122, and a support bar 123, with the copper foil 121 and the low-voltage insulation layer 122 alternately arranged. The copper foil 121 is formed by winding a whole sheet of copper foil, and the low-voltage insulation layer 122 is overlapped with the copper foil 121 and wound together. The low-voltage winding 120 is provided with at least one heat dissipation channel, which is located between adjacent copper foils 121 and low-voltage insulation layers 122, and the support bar 123 is located within the heat dissipation channel to support and isolate adjacent copper foils 121 and low-voltage insulation layers 122. The heat dissipation channel allows the heat generated by the low-voltage winding 120 during the operation of the dry-type transformer 10 to be released, preventing the dry-type transformer 10 from overheating and failing.

[0045] Referring to Figures 5-7 and 9, the high-voltage winding 130 includes a winding body 1310, a high-voltage coil 1320, and a high-voltage insulation layer 1330. A conductor is wound around the outside of the winding body 1310 to form the high-voltage coil 1320, which comprises several coil segments spaced apart along the axial direction of the high-voltage winding 130. The high-voltage insulation layer 1330 encloses the high-voltage coil 1320 and the winding body 1310. The winding body 1310 of the high-voltage winding 130 eliminates the need for a rigid insulating inner liner, resulting in better heat dissipation. The absence of an interface between the high-voltage insulation layer 1330 and the rigid insulating inner liner eliminates surface discharge on the rigid insulating inner liner, saving materials and reducing costs.

[0046] In this embodiment, the winding body 1310 includes several winding plates 1311 and several fixing rings 1400. The winding plates 1311 are spaced apart and evenly distributed circumferentially inside the high-voltage winding 130. Each winding plate 1311 is arranged along the axial direction of the high-voltage winding 130 and has several comb teeth. The high-voltage coil 1320 adopts a disc coil, that is, it includes several disc coils, and at least one disc coil is arranged between two adjacent comb teeth on the winding plate 1311. The number of winding plates 1311 is at least two, that is, two, three, four or more. In order to ensure the wire is wound securely and to save materials as much as possible, the number of winding plates 1311 in the 10kV / 1000kVA dry-type transformer is set to twelve.

[0047] In one embodiment, the winding plate 1311 is a rectangular plate with a fixed comb tooth structure. The longer side of the winding plate 1311 is arranged along the axial direction of the high voltage winding 130. The winding plate 1311 is also provided with a plurality of winding grooves 1312. The plurality of winding grooves 1312 are arranged radially along the high voltage winding 130 and spaced apart along the axial direction of the high voltage winding 130, so that the winding plate 1311 is in the shape of a comb tooth. The height of the comb teeth on the winding plate 1311 along the axial direction of the high-voltage winding 130 is defined as the tooth height. The tooth height at both ends and the middle of the winding plate 1311 is greater than the tooth height of other parts. This is because the ends of the high-voltage coil 1320 need to withstand higher impulse voltages. Setting the tooth height at both ends of the winding plate 1311 to be larger can enhance the impulse resistance. Since the middle of the winding plate 1311 needs to have a tap joint, setting the tooth height in the middle of the winding plate 1311 to be larger will increase the distance between the two adjacent winding slots 1312, which can provide space for the tap joint leading out from the middle of the winding plate 1311. At least one coil disc is set between two adjacent comb teeth on the winding plate 1311, so that at least one coil disc is set in each winding slot 1312, and the high-voltage coil 1320 is reasonably distributed and the coil segments are spaced apart. Simultaneously, the comb tooth region with slightly larger tooth height is defined as the high comb tooth region, and the comb tooth region with slightly smaller tooth height is defined as the low comb tooth region. The winding plate 1311, along the axial direction of the high-voltage winding 130 from one end to the other, sequentially forms a first high comb tooth region, a first low comb tooth region, a second high comb tooth region, a second low comb tooth region, and a third high comb tooth region. The tooth heights of the first high comb tooth region, the second high comb tooth region, and the third high comb tooth region can be the same or different. Furthermore, the first high comb tooth region and the third high comb tooth region can be symmetrically arranged about the second high comb tooth region, and the first low comb tooth region and the second low comb tooth region can also be symmetrically arranged about the second high comb tooth region, or they can be asymmetrically arranged.

[0048] When several winding plates 1311 are evenly distributed around the circumference, the two ends of all winding plates 1311 are set flush, and the winding slots 1312 on all winding plates 1311 are matched one-to-one with the high voltage winding 130 around the circumference. Each coil is wound around the corresponding winding slot 1312 on all winding plates 1311 by a conductor around the circumference, so that the force is balanced and the mechanical strength is good.

[0049] In other embodiments, to allow for the placement of the taps, the winding plates can be fixed in an uneven manner, that is, the distance between two adjacent winding plates is not equal. For example, the distance between two adjacent winding plates is greater than the distance between any other two adjacent winding plates. In this case, each tap is led out from between the two adjacent winding plates. Thus, the tooth height of the comb teeth in the middle of the winding plate does not need to be set to be larger, and the placement position of each tap can still be left.

[0050] In other embodiments, the winding plate can adopt a movable comb-tooth structure. The winding plate is a strip-shaped structure, with its length direction arranged along the axial direction of the high-voltage winding. The winding plate has several movable winding elements, and a winding groove is formed between adjacent winding elements, thus forming several winding grooves spaced apart along the axial direction of the high-voltage winding, making the winding plate comb-shaped. At least one coil is provided in each winding groove. A movable slot is provided on the winding element, and the winding element and the winding plate are slidably connected through the movable slot. For example, the winding plate is an I-shaped strip, and the movable slot of the winding element is a T-shaped slot. At least part of the winding plate passes through the movable slot, allowing the winding element to move along the winding plate. The movable comb-tooth structure of the winding body facilitates flexible adjustment of the winding element position according to the shape and structure of the high-voltage coil, broadening the applicability of the winding body and further reducing costs.

[0051] In this embodiment, the winding plate 1311 can be formed by molding and curing a rectangular fiberglass plate impregnated with epoxy resin, and then milling winding grooves 1312 into the fiberglass plate to form the winding plate 1311. Alternatively, it can be integrally cast and cured to directly form a comb-shaped winding plate, simplifying the process. The material of the winding plate is the same as described above and will not be repeated. When winding the conductor, the winding plate 1311 can be fixedly connected to the outer peripheral surface of the winding fixture with an adhesive, which minimizes material usage and saves costs. The adhesive is a two-component high-temperature resistant epoxy resin, but other adhesives can also be used. However, it is necessary to ensure that the adhesive can firmly bond the winding fixture to the winding plate 1311 and withstand high temperatures to accommodate the high-temperature injection of the high-voltage insulation layer 1330 onto the winding body 1310.

[0052] The winding body 1310 is made of the aforementioned fiber-reinforced composite material, which has the characteristics of being lightweight and high-strength. This gives the winding body 1310 good mechanical strength, effectively supporting the winding of the conductor and preventing damage. It also avoids the conductor being scattered and displaced by the injection impact force generated when silicone rubber is injected into the winding body 1310. Furthermore, the fiber-reinforced composite material has good heat resistance, preventing the winding body 1310 from deforming due to excessive heat generated by the high-voltage coil 1320 during the operation of the dry-type transformer 10.

[0053] Referring to Figures 7 and 9-11, the retaining rings 1400 are annular in shape. Several retaining rings 1400 are spaced apart along the axial direction of the high-voltage winding 130 and are coaxial with the high-voltage winding 130. The retaining rings 1400 are snapped into the winding plate 1311. The addition of retaining rings 1400 can keep the winding plate 1311 stable and prevent the winding plate 1311 from moving or misaligning during the wire winding process and the high-voltage insulation layer injection process.

[0054] In this embodiment, the plurality of fixing rings 1400 includes two first fixing rings 1410. The shape of the first fixing ring 1410 matches that of the high voltage winding 130. It can be a circular ring, an elliptical ring, or other ring shapes. The two first fixing rings 1410 are respectively installed at the two ends of the winding plate 1311. The bottom of the winding groove 1312 at the end of the winding plate 1311 is provided with a first slot 1313 for securing the first fixing ring 1410. The first slot 1313 is set along the side wall of the winding groove 1312 near the end of the winding plate 1311, so that the first fixing ring 1410 can be set tightly against the side wall of the winding groove 1312 at the end of the winding plate 1311, ensuring the connection strength between the first fixing ring 1410 and the winding plate 1311. For ease of description, the space in the winding groove 1312 at the end of the winding plate 1311 other than the space where the first fixing ring 1410 is installed is defined as the second slot 1314. That is, on the same winding plate 1311, from one end to the other, the first slot 1313, the second slot 1314, several winding grooves 1312, the second slot 1314, and the first slot 1313 are arranged in sequence at intervals.

[0055] Each of the two opposing first fixing rings 1410 has a plurality of grooves 1411 on its back-to-back plate surface. The grooves 1411 are arranged radially along the first fixing ring 1410, and the plurality of grooves 1411 are evenly distributed circumferentially along the first fixing ring 1410. Each groove 1411 corresponds one-to-one with a plurality of winding plates 1311. The length of the groove 1411 along the circumference of the first fixing ring 1410 is defined as the width of the groove 1411, and the length of the winding plate 1311 along the circumference of the winding body 1310 is defined as the width of the winding plate 1311. The width of the groove 1411 matches the width of the winding plate 1311. The length of the groove 1411 along the axial direction of the first fixing ring 1410 is defined as the depth of the groove 1411, and the length of the comb teeth on the winding plate 1311 along the axial direction of the winding body 1310 is defined as the width of the comb teeth. The depth of the groove 1411 matches the width of the winding plate 1311. The width of the comb teeth at the end of the winding plate 1311 is matched; one end of the winding plate 1311 with comb teeth is defined as the top end of the winding plate 1311, and the other end is defined as the bottom end of the winding plate 1311. The length from the top end to the bottom end of the winding plate 1311 is defined as the height of the winding plate 1311. The height of the winding plate 1311 is matched with the ring width of the first fixing ring 1410, so that after the winding plate 1311 and the first fixing ring 1410 are engaged and connected, the comb teeth at the end of the winding plate 1311 can be accommodated in the groove 1411.

[0056] The inner circumference of the first fixing ring 1410 is provided with a plurality of third slots 1412. The plurality of third slots 1412 are arranged radially along the first fixing ring 1410 and correspond one-to-one with a plurality of winding plates 1311. The plurality of third slots 1412 are connected one-to-one with a plurality of grooves 1411. The length of the third slot 1412 along the radial direction of the first fixing ring 1410 is defined as the length of the third slot 1412. The distance between the length of the third slot 1412 and the bottom wall of the first slot 1313 is... The distance between the bottom ends of the winding plate 1311 is matched, allowing the first retaining ring 1410 to be engaged with the first retaining groove 1313 via the third retaining groove 1412. The length of the first retaining groove 1313 along the axial direction of the winding plate 1311 is defined as the groove width of the first retaining groove 1313, and the length of the groove 1411 of the first retaining ring 1410 along its axial direction is defined as the thickness of the first retaining ring 1410. The groove width of the first retaining groove 1313 matches the thickness of the first retaining ring 1410. Thus, the dimensions of the first retaining ring 1410 and the first retaining groove 1313 are perfectly matched, so that the first retaining ring 1410 can be engaged in the first retaining groove 1313 without the need for adhesive fixation. The distance from the bottom wall of the first slot 1313 to the bottom end of the winding plate 1311 is less than the distance from the bottom wall of the second slot 1314 to the bottom end of the winding plate 1311, so that the first slot 131 and the second slot 1314 form a stepped structure. The stepped structure can securely hold the first fixing ring 1410 and prevent the first fixing ring 1410 from moving. At least one first mounting hole 1413 is provided between two adjacent third slots 1412 on the first fixing ring 1410 for passing through the air passage 240. In this embodiment, two first mounting holes 1413 are provided between two adjacent third slots 1412 on the first fixing ring 1410. In one group of two adjacent third slots 1412, no first mounting hole 1413 may be provided, which can be used as a cross-line channel or lead-out tap during wire winding. In other embodiments, the first fixing ring can also be fixed in the first slot by an adhesive, as long as the first fixing ring and the first slot can be fixedly connected; one, three or more first mounting holes can be provided between two adjacent third slots on the first fixing ring, and the first mounting holes can also be arbitrarily set on the first fixing ring, as long as the air passage component can be securely installed.

[0057] In this embodiment, the plurality of fixing rings 1400 further includes a second fixing ring 1420. The shape of the second fixing ring 1420 is the same as that of the first fixing ring 1410, which is a circular ring, an elliptical ring, or other ring shape. The width of the fixing ring 1400 along the radial direction of the winding body 1310 is defined as the ring width of the fixing ring 1400. The ring width of the second fixing ring 1420 is smaller than the ring width of the first fixing ring 1410, and the inner circumferential dimension of the second fixing ring 1420 is larger than the inner circumferential dimension of the first fixing ring 1410. The outer circumferential dimension of the second fixing ring 1420 is smaller than the outer circumferential dimension of the first fixing ring 1410. The second fixing ring 1420 is disposed in the middle of the winding plate 1311. A fifth slot 1315 is provided in the middle of the winding plate 1311. The fifth slot 1315 is located at the top of a comb tooth in the middle of the winding plate 1311. The second fixing ring 1420 is engaged in the fifth slot 1315, ensuring an effective connection between the second fixing ring 1420 and the winding plate 1311. The width of the second fixing ring 1420 is smaller than the height of the winding plate 1311, which facilitates the lead-out of the tap during wire winding and also facilitates the flow of silicone rubber during the molding of the high-voltage insulation layer. Several fourth slots 1421 are provided radially along the inner circumference of the second fixing ring 1420. The number of fourth slots 1421 is equal to the number of winding plates 1311. The width of the fourth slot 1421 is defined as the length of the fourth slot 1421 along the circumferential direction of the second fixing ring 1420, and the width of the fourth slot 1421 matches the width of the winding plate 1311. The length of the fourth slot 1421 is defined as the distance from one end of the fourth slot 1421 radially along the winding body 1310 to its other end, and the length of the fourth slot 1421 is equal to or slightly less than the distance from the fifth slot 1315 to the bottom end of the winding plate 1311. The thickness of the second fixing ring 1420 is defined as the length of the second fixing ring 1420 along its axial direction, and the height of the fifth slot 1315 is defined as the length of the fifth slot 1315 along the axial direction of the winding body 1310, and the thickness of the second fixing ring 1420 matches the height of the fifth slot 1315. Thus, the dimensions of the second fixing ring 1420 and the fifth slot 1315 are perfectly matched, allowing the second fixing ring 1420 to be secured in the fifth slot 1315 via the fourth slot 1421 without the need for adhesive. Accordingly, no wire is wound in the fifth slot 1315. In other embodiments, multiple second fixing rings can be provided, spaced apart and secured to the winding plate.At least one second mounting hole 1422 is provided between two adjacent fourth slots 1421 on the second fixing ring 1420. The second mounting hole 1422 corresponds to the first mounting hole 1413, that is, they are identical in shape and number, and are used to accommodate the air passage component 240. In this embodiment, two second mounting holes 1422 are provided between two adjacent fourth slots 1421 on the second fixing ring 1420. In one group of two adjacent fourth slots 1421, no second mounting hole 1422 may be provided, which can be used as a cross-line channel or a lead-out tap during wire winding. In other embodiments, the second fixing ring and the fifth slot can also be fixed with adhesive, as long as the second fixing ring and the fifth slot can be fixedly connected. One, three or more second mounting holes can be provided between two adjacent fourth slots on the second fixing ring. The second mounting holes can also be arbitrarily set on the second fixing ring, as long as they can correspond to the first mounting holes to secure the air passage component.

[0058] The fixing ring 1400 is also made of glass fiber impregnated with epoxy resin. Multiple layers of glass fiber cloth impregnated with epoxy resin are stacked to a certain thickness and then molded and cured to form a ring-shaped fiberglass plate. The fixing ring 1400 can also be a glass fiber reinforced polyimide composite material plate, which is easy to obtain and process. The fixing ring 1400 made of fiber-reinforced composite material has good mechanical strength, can stably support the winding of the conductor, and is not easily damaged, avoiding the large injection impact force generated when silicone rubber is injected outside the winding body 1310, which could cause the conductor to be scattered and displaced. Furthermore, the fiber-reinforced composite material has good heat resistance, which can prevent the fixing ring 1400 from deforming due to overheating during the operation of the dry-type transformer 10. In this embodiment, the fixing ring 1400 is formed by molding and curing. In other embodiments, it can also be integrally cast and cured to directly form the auxiliary part, simplifying the process. The material of the fixing ring is the same as described above and will not be repeated.

[0059] Referring to Figures 12-14, this application also discloses a mold assembly 200 for manufacturing a high-voltage winding 130. The mold assembly 200 includes a core mold 210, two mandrels 220, several fixing plates 230, and several air passage components 240. The core mold 210 is a hollow cylindrical body made of steel. The hollow core mold 210 is lightweight, easy to install, uses less material, and has low production costs. The outer periphery of the core mold 210 matches the inner periphery of the fixing ring 1400; that is, the cross-section of the core mold 210 can be circular, elliptical, or other shapes, so that the winding body 1310 can be securely fitted onto the outer periphery of the core mold 210. In other embodiments, the core mold can also be a solid cylindrical body, which has high strength and good overall integrity. During the winding of the high-voltage coil 1320 and the forming of the high-voltage insulation layer 1330, the winding body 1310 is located on the outer circumferential surface of the core mold 210, and the axial length of the winding body 1310 along the core mold 210 is less than or equal to the axial length of the core mold 210.

[0060] Two mandrels 220 are fixedly connected along the axial direction of the mandrel 210 at the center positions of its two end faces. The mandrels 220 are rod-shaped structures with a rectangular cross-section, used to mount the fixing plate 230 and to fix the mold assembly 200 in the mold of the injection molding machine during silicone rubber injection molding, or in the mold of the casting equipment during casting. The mandrels 220 and the mandrel 210 can be fixed by welding. The mandrels 220 and the mandrel 210 are made of the same material, metal steel. In other embodiments, the cross-section of the mandrel can be circular or other shapes, and the mandrel can also be made of other metal materials, as long as it fulfills its function of mounting the fixing plate and fixing the mold assembly.

[0061] Several fixing plates 230 are spaced apart and connected to one of the mandrels 220. The fixing plates 230 are elliptical plate structures, and their shape and size are the same as the outer circumference of the first fixing ring 1410. The fixing plates 230 are provided with through holes 231 and several third mounting holes 232. The through holes 231 are located at the center of the fixing plates 230 and are used to pass through the mandrels 220. The shape of the through holes 231 corresponds to and matches the mandrels 220, so that the mandrels 220 can be inserted and secured in the through holes 231, preventing the fixing plates 230 from twisting or sliding on the mandrels 220, which would cause the air passage component 240 to be unable to be installed securely and affect the air passage quality of the high-voltage winding 130. The number and position of the third mounting holes 232 correspond to the first mounting holes 1413 and the second mounting holes 1422, and the mounting holes cooperate with each other to pass through the air passage component 240. In this embodiment, two fixing plates 230 are provided. Compared to providing only one fixing plate 230, two fixing plates 230 can better limit the air passage component 240, preventing the air passage component 240 from shaking due to instability and failing to pass through the second mounting hole 1422, thus preventing the air passage from forming. Furthermore, it can prevent the air passage component 240 from being inserted at an angle in each mounting hole, causing the air passage ultimately formed in the high-voltage winding 130 to be skewed and unable to penetrate the high-voltage insulation layer 1330 along the axial direction of the high-voltage winding 130, thus failing to achieve the purpose of heat dissipation. In other embodiments, one, three, or more fixing plates can also be provided, as long as the air passage component can be stably installed.

[0062] In one embodiment, the air passage component 240 is a rod-shaped structure with a capsule-shaped cross-section. The cross-sectional shape of the air passage component 240 corresponds to and matches the shape and size of the first mounting hole 1413, the second mounting hole 1422, and the third mounting hole 232. That is, the first mounting hole 1413, the second mounting hole 1422, and the third mounting hole 232 are capsule-shaped, facilitating the stable installation of the air passage component 240. In another embodiment, the air passage component 240 is a rod-shaped structure with a rounded trapezoidal cross-section. The cross-sectional shape of the air passage component 240 corresponds to and matches the shape of the second mounting hole 1422 and the third mounting hole 232. That is, in this case, the first mounting hole 1413, the second mounting hole 1422, and the third mounting hole 232 are rounded trapezoidal holes, facilitating the stable installation of the air passage component 240. One end of the air passage component 240 has a taper, that is, the outer diameter of one end of the air passage component 240 gradually decreases along its axial direction away from the air passage component 240, facilitating the insertion of the air passage component 240 into each mounting hole.

[0063] Referring to Figures 5, 6, and 8, taking the A-phase transformer 100 as an example, the conductors are circumferentially wound on the outer circumferential surface of the winding body 1310 to form a high-voltage coil 1320. Specifically, the conductors are wound in the winding slots 1312 of the winding plate 1311, so that the high-voltage coils 1320 are spaced apart along the axial direction of the high-voltage winding 130. After the conductors are wound, two external connections are formed at their ends, namely the first external connection D and the second external connection X. The first external connection D is used to connect cables and other external connections, and the second external connection X is used to connect other external connections, such as in a three-phase transformer, for interconnection with other phase transformers. Furthermore, six taps are led out from the middle of the winding body 1310 along its axial direction, namely tap 2, tap 3, tap 4, tap 5, tap 6 and tap 7. The six taps form a tap changer. For ease of description, tap 2, tap 4 and tap 6 are defined as the first tap changer, and tap 3, tap 5 and tap 7 are defined as the second tap changer. The first tap changer and the second tap changer are arranged in parallel. The six taps form the tapping device of the high-voltage coil 1320, which is used to adjust the voltage of the dry-type transformer 10 according to different operating conditions.

[0064] The high-voltage insulation layer 1330 wraps around the high-voltage coil 1320 and the winding body 1310 to form the high-voltage winding 130. In one embodiment, the high-voltage insulation layer 1330 is made of high-temperature vulcanized silicone rubber, which makes the high-voltage insulation layer 1330 more stable, has higher mechanical properties, and better adhesion to the high-voltage coil 1320 and the winding body 1310, effectively extending the service life of the high-voltage insulation layer 1330; moreover, the silicone rubber filler is evenly dispersed, preventing partial discharge due to filler agglomeration, resulting in better product performance. The high-temperature vulcanized silicone rubber uses a high-temperature vulcanized silicone rubber material system, specifically including raw rubber, reinforcing agents, flame retardants, heat resistant agents, and other auxiliary materials. In another embodiment, the high-voltage insulation layer 1330 can also be made of liquid silicone rubber, which uses a liquid silicone rubber material system, specifically including base rubber, reinforcing agents, flame retardants, heat resistant agents, and other auxiliary materials.

[0065] Referring to Figures 6-14, when the high-voltage coil 1320 is wound using a pancake winding method, firstly, the winding body 1310 is assembled. The first fixing ring 1410 and the second fixing ring 1420 are clamped onto the winding plate 1311 to form the winding body 1310. Specifically, the third slots 1412 of the two first fixing rings 1410 are respectively clamped into the first slots 1313 at both ends of the winding plate 1311, and the comb teeth at the end of the winding plate 1311 are accommodated in the grooves 1411, so that the two first fixing rings 1410 are respectively clamped and connected to both ends of the winding plate 1311; the fourth slot 1421 is clamped into the fifth slot 1315, so that the second fixing ring 1420 is clamped and connected to the middle part of the winding plate 1311.

[0066] Next, assemble the mold assembly 200. Place the winding body 1310 onto the mold assembly 200, and fix at least two fixing plates 230 onto the mandrel 220 on one side of the mold assembly 200, that is, fix the fixing plates 230 at intervals through through holes 231 onto the outer periphery of the mandrel 220. Further, before this step, a release agent can be applied to the outer periphery of the mandrel 210 to facilitate demolding after the high-voltage winding 130 is formed.

[0067] Then, the high-voltage coil 1320 is wound. During the winding process of each coil, after the wire is wound to the first preset number of turns, the air passage 240 is inserted into the preset position along the axis of the winding body 1310, and then the wire is wound to the second preset number of turns.

[0068] In one application scenario, as shown in Figures 5, 6, and 8, the conductor includes a first conductor and a second conductor. Both the first and second conductors are continuous conductors, and both are covered with an insulating layer. This insulating layer can be a polyimide film, polyester film, fiberglass film, or other insulating materials such as insulating varnish, or a combination of multiple insulating materials. For ease of description, the end of the winding body 1310 near the fixing plate 230 is defined as the first end, and the other end of the winding body 1310 is defined as the second end. The first conductor is wound from the first end of the winding body 1310 along the axial direction of the high-voltage winding 130 to the middle of the winding body 1310, and three taps are led out. The inner turn of the first conductor at the first end of the winding body 1310 forms a first external connection D exposed outside the high-voltage insulating layer 1330, that is, the first external connection D is led out from the inner turn of the first coil (i.e., the beginning end of the first conductor).

[0069] Specifically, the first conductor is wound from the first end of the winding body 1310 to the second end of the winding body 1310 to form a first coil. The first conductor is wound in the second slot 1314 of the first winding groove 1412 at the first end of the winding body 1310 according to a first preset number of turns, wherein the first preset number of turns is M. After the winding is completed, an insulating support material is wrapped around the first coil with M turns. The insulating support material is fiberglass mesh, electrical composite material, or silicone cloth. The air passage 240 is inserted from the first end of the winding body 1310 along the axial direction of the winding body 1310 into a first preset position inside the winding body 1310. That is, the tapered end of the air passage 240 passes through the third mounting hole 232 and the first mounting hole 1413 on the first fixing ring 1410 near the fixing plate 230 in sequence, and along the first preset position with M turns. The outer periphery of the first coil moves toward the second end of the winding body 1310 until the air passage 240 reaches the first preset position and stops moving. The first preset position is at the second comb tooth of the first end of the winding body 1310, to prevent the air passage 240 from extending into the second winding groove 1312 of the first end of the winding body 1310 and affecting the winding of the second coil. After all the air passages 240 are inserted into the first preset position, a layer of insulating support material is wrapped around the outer periphery of all the air passages 240. The insulating support material does not cover the tail end of the first conductor to avoid affecting the continuous winding of the first conductor. Then, the first conductor is wound around the outer periphery of the insulating support material according to the second preset number of turns N until the winding of the first coil is completed. The sum of the second preset number of turns N and the first preset number of turns M is the total number of turns of the coil of the high voltage coil 1320. Furthermore, before installing the air duct component 240, a lubricating material can be applied to the outer periphery of the air duct component 240 to form a lubricating layer. The lubricating layer is made of a release agent, which facilitates the smooth removal of the air duct component 240 after the high-voltage insulation layer 1330 is formed. In this embodiment, the insulating support material is set to two layers for clamping the air duct component 240. In other embodiments, it can also be set to three, four, or more layers.

[0070] Then, the first conductor continues to wind the second coil towards the second end of the winding body 1310, that is, the outer turn conductor end of the first coil extends into the corresponding second winding groove 1312 on all winding plates 1311 and is wound according to the first preset number of turns M; after the winding is completed, an insulating support material is wrapped around the outer layer of the second coil with M turns; the air passage 240 is inserted into the second preset position in the winding body 1310 along the axial direction of the winding body 1310 until the air passage 240 reaches the second preset position and stops moving, wherein the second preset position is at the third comb tooth of the first end of the winding body 1310, to avoid the air passage 240 extending into the third winding groove 1312 of the first end of the winding body 1310 and affecting the winding of the third coil; after all the air passage 240s are inserted into the second preset position, an insulating support material is wrapped around the outer periphery of all the air passage 240s; then the first conductor continues to be wound around the outer periphery of this insulating support material according to the second preset number of turns N until the second coil is wound.

[0071] Then, following the method of winding the second coil, the remaining coils are wound in sequence until the first wire is wound to the middle of the winding body 1310. Three taps are then led out from the outer turns of the three coils adjacent to the first end of the winding body 1310 on the side of the second fixing ring 1420. These taps are shown as tap 6, tap 4 and tap 2 in Figure 5, forming the first tap switch. At this point, the winding of the first wire is complete.

[0072] Then, each air passage component 240 is inserted into the second mounting hole 1422 until one end of the air passage component 240 is flush with the plate surface of the second fixing ring 1420 facing the second end of the winding body 1310 and stops moving. The second wire is wound from the middle of the winding body 1310 to the second end of the winding body 1310. Specifically, the second wire is wound in the winding groove 1312 adjacent to the side of the second fixing ring 1420 facing the second end of the winding body 1310, and three taps are led out from the outer turn wire end of the three-panel coil adjacent to the side of the second fixing ring 1420 facing the second end of the winding body 1310, namely tap 3, tap 5 and tap 7 as shown in Figure 5, to form a second tap switch; then the winding continues until the second wire is wound to the second slot 1314 of the last winding groove 1412 at the second end of the winding body 1310 and forms a final panel coil. The specific winding method and the installation method of the air passage component 240 are the same as those of the first wire. The second conductor, located at the outer turn of the second end of the winding body 1310, forms a second external connection X exposed outside the high-voltage insulation layer 1330. That is, the second external connection X is led out from the outer turn of the final coil (i.e., the end of the second conductor). At this time, the air passage 240 passes through the first mounting hole 1413 on the first fixing ring 1410 at the second end of the winding body 1310, thus completing the winding of the second conductor. In other embodiments, the taps can be distributed at other positions in the middle of the high-voltage coil on the winding body, according to the actual coil structure design requirements.

[0073] When the conductor is wound, it is wound in a corresponding winding groove 1312 on all winding plates 1311, so that each coil formed by the conductor is perpendicular to the axis of the high voltage winding 130. The winding is convenient and the conductor is neatly arranged. The winding plate 1311 is subjected to uniform force and has good mechanical strength.

[0074] Thus, a disc-shaped high-voltage coil 1320 is formed. This high-voltage coil structure has good mechanical strength and strong ability to withstand the electromotive force generated by short-circuit current. Compared with the layered high-voltage coil, it has more discs.

[0075] The conductor is wound around the winding body 1310 to form a high-voltage coil 1320, which is thus ring-shaped. The width of the high-voltage coil 1320 is defined as the ring width. The width of the high-voltage coil 1320 is consistent in all its radial sections, meaning that the outer surface of the high-voltage coil 1320 is equidistant from the outer circumference of the high-voltage winding 130, ensuring overall force balance in the high-voltage coil 1320. Of course, considering practical operation, the width of the high-voltage coil in its radial sections may not be exactly the same, as long as it is approximately the same.

[0076] In this embodiment, the second conductor is wound from the middle of the winding body 1310 to its second end. In other embodiments, the second conductor may also be wound from the second end of the winding body to the middle of the winding body 1310, except that the second external connector X is formed first, and then the tap 7, tap 5 and tap 3 are formed in sequence.

[0077] In this embodiment, the tap changer includes six taps, giving the dry-type transformer 10 five adjustable voltage levels. In other embodiments, the tap changer may also include four taps, with the first and second tap changes each including two taps. In this case, the dry-type transformer has three adjustable voltage levels, as long as it meets the actual usage requirements of the dry-type transformer. At this point, the high-voltage coil winding is complete.

[0078] Next, the winding body 1310 with the high-voltage coil 1320 wound on it is placed into the mold of the injection molding machine along with the mold assembly 200, and silicone rubber raw material is added. High-temperature vulcanized silicone rubber is injected into the periphery of the part to be injected to form a high-voltage insulation layer, thus obtaining a preform. In this process, after the high-voltage coil 1320 and the winding body 1310 are covered by high-temperature vulcanized silicone rubber or liquid silicone rubber through vacuum injection, the 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, so that the high-voltage winding 130 is hollow cylindrical in shape. It can be a hollow cylinder, a hollow elongated cylinder, or other hollow cylindrical shapes.

[0079] In other embodiments, when the high-voltage insulation layer is made of liquid silicone rubber, it can also be prepared by a casting process. A winding body with a high-voltage coil is placed into a mold of a casting device along with a mold assembly. Silicone rubber raw material is added, and liquid silicone rubber is poured around the periphery of the body to be cast to form a high-voltage insulation layer, resulting in a preform.

[0080] Finally, the preform is separated from the mold assembly 200, and the air duct component 240 is pulled out to obtain a high-voltage winding 130 with an axial air duct, specifically a high-voltage encapsulated disc winding. The axial air duct makes the high-voltage winding 130 more efficient in heat dissipation and has a wider range of applications; compared with traditional heat dissipation methods, it reduces the amount of wire used and lowers product costs. Since the wires in contact with both sides of the air duct component 240 are covered with insulating support material, the wires inside the air duct will not be exposed to the air after the air duct component 240 is pulled out to form the air duct, which helps to extend the service life of the high-voltage winding 130.

[0081] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A high-voltage winding, characterized in that, The high-voltage winding includes a winding body, a high-voltage coil, and a high-voltage insulation layer. The winding body includes several winding plates and several fixing rings. The winding plates are engaged with the fixing rings. The fixing rings are provided with several first mounting holes and several second mounting holes, which are used to accommodate air passage components. The conductors are wound on the winding body to form the high-voltage coil, which includes several coil discs. The high-voltage insulation layer encloses the high-voltage coil and the winding body. The high-voltage winding also includes several air passages, which are arranged along the axial direction of the high-voltage winding and penetrate the high-voltage insulation layer.

2. The high-voltage winding as described in claim 1, characterized in that, The winding plate is provided with a plurality of winding slots, and the plurality of winding plates are evenly distributed along the circumference of the high voltage winding. At least one coil is provided in each winding slot of the winding plate.

3. The high-voltage winding as described in claim 1, characterized in that, The plurality of fixing rings include two first fixing rings, and the plurality of winding plates are provided with two first slots respectively. The two first fixing rings are secured to both ends of the winding plate through the first slots, and a plurality of first mounting holes are provided between each pair of first slots.

4. The high-voltage winding as described in claim 1, characterized in that, The plurality of fixing rings include at least one second fixing ring, and the plurality of winding plates are provided with at least one fifth slot. The second fixing ring is engaged in the middle of the winding plate through the fifth slot, and a plurality of second mounting holes are provided between every two fifth slots.

5. The high-voltage winding as described in claim 1, characterized in that, The first mounting hole and the second mounting hole have the same shape and number, and the first mounting hole and the second mounting hole are provided correspondingly.

6. The high-voltage winding as described in claim 1, characterized in that, The cross-section of the air passage component is capsule-shaped or rounded trapezoidal, and the shape and size of the first mounting hole and the second mounting hole correspond to and match the cross-section of the air passage component; the outer diameter of one end of the air passage component gradually decreases along the axial direction away from the air passage component.

7. The high-voltage winding as described in claim 1, characterized in that, The high-voltage coil is provided with at least two layers of insulating support material for clamping the air passage component. The insulating support material is glass fiber mesh, electrical composite material or silicone cloth.

8. The high-voltage winding as described in claim 1, characterized in that, The outer periphery of the air passage component is provided with a lubricating layer, which is made of a release agent.

9. A mold assembly for manufacturing a high-voltage winding as described in any one of claims 1-8, characterized in that, The mold assembly includes a core mold, two mandrels, several fixing plates, and several air passage components. The two mandrels are fixedly connected to both ends of the core mold along the axial direction of the core mold. Several fixing plates are connected to one of the mandrels. The fixing plates are provided with through holes and several third mounting holes. The through holes are used to pass through the mandrels, and the third mounting holes are used to cooperate with the winding body to pass through the air passage components.

10. A method for manufacturing a high-voltage winding, used to manufacture a high-voltage winding as described in any one of claims 1-8, characterized in that, Includes the following steps: Step ①: Assemble the mold assembly and the winding body, and then fit the winding body onto the mold assembly; Step 2: Wind the wire around the winding body to form a high-voltage coil. During the winding process of each coil, after the wire has been wound to the first preset number of turns, insert the air passage component along the axial direction of the winding body to the preset position, and then wind the wire to the second preset number of turns. Step 3: Place the winding body with the high-voltage coil wound on it into the injection molding machine as the injection body to be injected, and inject silicone rubber into the entire periphery of the injection body to form a high-voltage insulation layer; or, place the winding body with the high-voltage coil wound on it into the casting equipment as the casting body to be cast, and cast silicone rubber into the periphery of the casting body to form a high-voltage insulation layer. Step 4: Pull out the air passage component to obtain the high-voltage winding with an axial air passage.

Images