Transformer

Abstract

transformer (1), comprising a core (30) with an upper yoke (31), a lower yoke (32) and at least one leg (33), at least one winding (40) arranged around the leg (33), a frame (20) with a bottom part (23) and a top part (21) and support elements (25) connecting the bottom part (23) to the top part (21), wherein the frame at least partially encloses the core (30) and the winding (40), at least one core clamping element (50) for applying a first force (FK) to the core (30) via the frame (20), at least one winding tensioning element (60) for applying a second force (FW) to the winding (40) via the frame (20), wherein the core clamping element (50) and the winding clamping element (60) are designed such that the first force (FK) and the second force (FW) can be adjusted independently of each other, the bottom part (23) comprises a first bottom profile (230) and a second bottom profile (240) and the head section (21) comprises a first head profile (210) and a second head profile (220), where the bottom profiles (230, 240) and the top profiles (210, 220) are designed as Z-profiles, and the first force (FK) and the second force (FW) are aligned parallel to each other and act against a vertical direction of the transformer (1), wherein the first head profile (210) and the second head profile (220) each have an inner web (27) and the core clamping element (50) is arranged between the respective inner web (27) and the upper yoke (31).

Description

[0001] The invention relates to a transformer with a frame and a core.

[0002] DE 39 18 187 A1 describes an iron core for transformers with two ring yokes and at least one leg. An electrical coil is arranged around each leg. The ring yokes, one leg, and the electrical coil are connected and clamped together with a specific force using clamping devices designed as threaded rods, clamping strips, and nuts.

[0003] From WO 2007 / 036 956 A1, a transformer with a core and a frame holding the core is known. The frame has at least four crossbeams, which are spanned in pairs over the upper branch and the lower branch of a core lamination stack. Each crossbeam consists of at least two tubular elements with a rectangular cross-section, which are parallel and spaced apart from each other and connected by a plurality of clamps. At least two pairs of clamps form support and locking clamps for the resin body that encapsulates the transformer windings. The two outermost clamps of each crossbeam accommodate clamping discs for tension rods to clamp the crossbeams against the core lamination stack.

[0004] GB 990 520 A discloses a device for the simultaneous pressing of the cores and windings of large transformers with three wound, layered legs, using press rods running parallel to them and arranged within the winding support cylinder, and pressure plates and webs located on both sides of the yokes, running parallel to them, into which the press rods engage. The press rods, which lie close to the legs, serve in conjunction with the winding support cylinder for core pressing and simultaneously as pull rods for adjustable winding pressing. Connecting elements between the pressing systems on both sides of the core are provided for adjusting the core pressing.

[0005] US 2011 / 0254647A1 discloses a dry-type transformer system comprising a transformer and an enclosure. The transformer has primary and secondary windings, a core extending through the primary and secondary windings, and upper and lower core clamps securing the top and bottom of the core. The enclosure has a base supporting the transformer and featuring an air inlet, a top with an air outlet, and side walls surrounding the transformer.

[0006] Against this background, the invention proposes a transformer according to claim 1. Advantageous embodiments of the invention are described in the dependent claims.

[0007] The invention proposes a transformer comprising - a core with an upper yoke, a lower yoke and at least one leg, - at least one winding arranged around the leg, - a frame comprising a base and a head section, as well as support elements connecting the base to the head section, wherein the frame at least partially encloses the core and the winding, - at least one core clamping element for applying a first force to the core via the frame, - at least one winding tensioning element for applying a second force to the winding via the frame, - wherein the core clamping element and the winding clamping element are designed such that the first force and the second force can be adjusted independently of each other, - the base part comprises a first base profile and a second base profile, - the headboard includes a first head profile and a second head profile, - the bottom profiles and the head profiles are designed as Z-profiles and - the first force and the second force are aligned parallel to each other and act against a vertical direction of the transformer, whereby - the first head profile and the second head profile each have an inner web and the core clamping element is arranged between the respective inner web and the upper yoke.

[0008] This transformer allows different forces to be applied to the core and windings via the frame. This is particularly advantageous when the core consists of yokes and / or legs made of an amorphous metal (e.g., an iron-silicon alloy). Because the yokes and legs are composed of blocks made up of numerous layered thin films, it is crucial that the core is subjected to and held together by a defined force. This force is significantly smaller than the force typically required to tension the windings. Excessively high forces, such as those typically applied to a core during tensioning, lead to internal stresses in an amorphous metal core. These stresses reduce the magnetic permeability and consequently increase hysteresis losses. This negatively impacts the overall efficiency of the transformer.

[0009] Furthermore, the transformer enables particularly easy assembly of all parts through the use of winding and core clamping elements. The design of these elements allows for preset adjustment, ensuring that preset forces act on the windings and core after assembly.

[0010] The transformer is preferably a high-voltage transformer, medium-voltage transformer or local network transformer, or a transformer from the voltage level of medium voltage or high voltage.

[0011] The core of the transformer consists of a lower yoke, an upper yoke, and at least one leg. Depending on the transformer type, any number of legs can be used, e.g., two, three, or five.

[0012] A winding is arranged around at least one of the legs. This winding can be either a single piece or multiple pieces. Furthermore, this winding can be configured as a high-voltage winding and / or low-voltage winding and / or main winding and / or regulating winding.

[0013] The frame consists of at least one base section, one top section, and at least one support element. The base section, the top section, the base profiles, and the top profiles can be made of metal, plastic, and / or composite materials.

[0014] The top and bottom sections can also each be formed in one piece. These are then designed as a hat profile.

[0015] Furthermore, the first and second bottom profiles are arranged around the lower yoke and the first and second head profiles around the upper yoke in a form-fitting and / or force-fit manner, thus fixing them in place. Elastic inserts are placed between the bottom / head profiles and the lower / upper yoke, which predefine and / or compensate for tolerances by adjusting the horizontal compressive force on the yokes.

[0016] In a one-piece design of the head section, the upper yoke is positively and / or force-fitted within it and is fixed by it. In a one-piece design of the base section, the lower yoke is likewise positively and / or force-fitted within it and fixed by it. Elastic inserts are placed between the base / head section and the lower / upper yokes to predefine and / or compensate for tolerances the compressive force on the yokes in the transverse direction.

[0017] The frame can also consist of a one-piece head section and a first and second base profile. Alternatively, the frame can consist of a first head profile and a second head profile, as well as a one-piece base section.

[0018] The core clamping elements are preferably arranged between the upper yoke and the head section and apply a force to the core via the frame. The winding clamping elements are preferably arranged between the windings and the head section and apply a force to the winding(s) via the frame.

[0019] Any number of core clamping elements can also be arranged between the inner web of the first head profile or the second head profile and the upper yoke.

[0020] The first and second end profiles each have an outer web. The winding clamping element is positioned between the respective outer web of the end profiles and the winding. Any number of winding clamping elements can be positioned between the outer web of the first or second end profile and the winding. In a transformer configuration with multiple windings, each winding is assigned at least one winding clamping element.

[0021] Furthermore, the first head profile has a first end and a second end, and the second head profile also has a first end and a second end. The head profiles are connected to each other at their respective first ends by at least one retaining element and at their respective second ends also by at least one further retaining element.

[0022] The first base profile has a first end and a second end, and the second base profile also has a first end and a second end. The base profiles are connected to each other at their respective first ends by at least one retaining element and at their respective second ends also by at least one retaining element. Preferably, the frame has at least four retaining elements.

[0023] If the base and headboard are designed as a single piece, then no retaining elements are present.

[0024] The head profiles and the bottom profiles are connected to each other at their ends by at least four support elements.

[0025] The core clamping element can preferably be designed as a screw with a pressure piece and / or as a pressure bolt with a clamping washer and / or as a pressure bolt with a compression spring.

[0026] The core clamping element can also be designed as a spring-elastic element and serves for force adjustment and tolerance compensation. It can also be made of other elastic materials (e.g., rubber) and / or have a different shape (e.g., sleeve, spring, cylinder, pressure capsule).

[0027] The winding tensioning element can be designed as a screw with a pressure piece and / or as a pressure bolt with a tension washer and / or as a pressure bolt with a compression spring.

[0028] The winding tensioning element can also be designed as a spring-elastic element and serves for force adjustment and tolerance compensation. It can also be made of other elastic materials (e.g., rubber) and / or have a different shape (e.g., sleeve, spring, cylinder, pressure capsule).

[0029] The core consists of an amorphous metal, in particular a soft magnetic metal, which forms an alloy of, for example, iron and silicon and / or boron and / or nickel. The yokes and legs are each monolithic blocks composed of numerous layers of amorphous metal bonded together to form a mechanically rigid structure. This structure can be created, for example, by cutting, gluing, and stacking or banding layers of amorphous foil. The core leg is composed of several blocks. These blocks vary in width, resulting in a leg with an oval to circular cross-section. The leg is cylindrical in its vertical dimension. This configuration applies to each individual leg of a core with multiple legs.

[0030] In the following, embodiments of the invention are explained in more detail by way of example with reference to the accompanying drawings. The individual features resulting therefrom are not limited to the individual embodiments, but can be combined or combined with individual features described above or with individual features of other embodiments. The details in the drawings are to be interpreted as illustrative only, not as limiting. The reference numerals contained in the claims are not intended to limit the scope of protection of the invention in any way, but merely refer to the embodiments shown in the drawings.

[0031] The drawings show in Fig. 1 an embodiment of a transformer with frame and core; Fig. 2 a detailed view of a core with a winding; Fig. 3a a detailed view of the core; Fig. 3b a sectional view through one leg; Fig. 4 the frame of the transformer; Fig. 5 a cross-sectional view of the transformer; Fig. 6 a sectional view with core clamping elements and winding clamping elements; Fig. 7a a first embodiment of a winding clamping element or core clamping element; Fig. 7b a sectional view of the first embodiment of a winding clamping element or core clamping element; Fig. 8a a second embodiment of a winding tensioning element or core tensioning element; Fig. 8b a sectional view of the second embodiment of the winding clamping element or core clamping element; Fig. 9a a third embodiment of a winding tensioning element or core tensioning element; Fig. 9b a sectional view of the third embodiment of the winding clamping element or core clamping element.

[0032] In Fig. Figure 1 shows a transformer 1 according to the invention. The transformer 1 has a core 30 consisting of a lower yoke 32, an upper yoke 31, and three legs 33. The legs 33 are arranged vertically at a defined distance from each other on the lower yoke 32. The upper yoke 31 rests on the legs 33. The transformer 1 also has a frame 20. This frame consists of a base 23 with a first base profile 230 and a second base profile 240. The base profiles 230 and 240 are designed as Z-profiles and are arranged parallel to each other. Both base profiles 230 and 240 have a first end 231, 241 and a second end 232, 242. In the embodiment shown here, both floor profiles 230, 240 are connected to each other via horizontally arranged retaining elements 291 and / or foot parts 292.The retaining elements 291 are designed here as bolts with internal threads, fastened with screws, but can also be designed in any other way, e.g., as threaded rods. The lower yoke 32 of the core 30 is arranged between the base profiles 230, 240. The Z-profile of the base profiles 230, 240 provides at least partial positive locking for the lower yoke 32. The retaining elements 291 also enable a defined force-fit fixing of the lower yoke 32 via the base profiles 230, 240. Windings 40 are arranged around the three legs 33 of the core 30. The upper yoke 31 is surrounded by a head section 21 with a first head profile 210 and a second head profile 220. In the embodiment shown here, the two head profiles 210, 220 and the two bottom profiles 230, 240 are connected to each other via four support elements 25 at the respective first and second ends 211, 221, 231, 241.In principle, the frame 20 can be constructed from only one head section 21, one base section 23 and one support element 25.

[0033] The head section 21 and the base section 23 can each be formed in one piece. These are then designed as a hat profile.

[0034] In Fig. Figure 2 shows the core 30 of the transformer 1 in detail. This core has three legs 33 with a lower yoke 32 and an upper yoke 31. However, the core 30 can also have two or five legs 33. In each case, at least one winding 40 is arranged around at least one leg 33. In the embodiment of the core 30 with five legs 33, windings 40 are preferably arranged only around the three middle legs 33. The two outer legs 33 do not have any windings 40 and serve only to improve the magnetic flux.

[0035] In Fig. Figure 3a shows a detailed view of the core 30. The upper yoke 31 and the lower yoke 32 are each constructed as blocks consisting of a plurality of stacked sheets of an amorphous metal. The amorphous metal is preferably a soft magnetic metal forming an alloy of iron and silicon and / or boron and / or nickel. In the fabrication of the individual blocks, the sheets, with a layer thickness of preferably 20 µm or more, are stacked on top of each other and adhesively bonded or banded together. To ensure very good magnetic permeability, the orientation of the sheets is selected accordingly. The orientation of the stacked sheets of the upper yoke 31, the lower yoke 32, and the legs 33 runs vertically in one direction, along an axis 80. The legs 33 and the yokes 31, 32 rest against each other and form a butt joint at the corresponding contact points.

[0036] In Fig. Figure 3b shows a section A through one of the legs 33. The leg 33 also consists of several blocks 331, 332, 333. Each block 331, 332, 333, like each yoke 31, 32, is constructed of superimposed sheets of an amorphous metal. In one leg 33, the inner block 331 is wider than the outer blocks 332, 333, so that the leg 33 has an oval to circular cross-section D in section A and is cylindrical in its vertical dimension, i.e., along the axis 80. The cylindrically shaped and stepped leg 33 is arranged inside the winding 40 and preferably fills it as completely as possible.

[0037] In Fig. Figure 4 shows the frame 20 of the transformer 1. The first / second bottom profiles 230, 240 and the first / second top profiles 210, 220 are connected to each other via four support elements 25. Preferably, the support elements 25 are connected to each other at the respective first ends 211, 221, 231, 241 and the respective second ends 212, 222, 232, 242 of the bottom profiles 230, 240 and the top profiles 210, 220. In the embodiment shown here, the support elements 25 are designed as threaded rods 251, each with a spacer tube 252. Each threaded rod 251 is designed as a tension threaded rod. The spacer tube 252 is pushed onto the threaded rod 251 and arranged between the bottom profiles 230, 240 and the top profiles 210, 220. Since the spacer tube 252 is shorter than the threaded rod 251, a threaded rod section 253 protrudes from each of the two ends of the support element 25.The head section 21 and the base section 23, in particular the head profiles 210, 220 and the base profiles 230, 240, can be screwed together using nuts 28. The nuts 28 can only be tightened until they reach the spacer tube 252. This prevents the frame 20 from being further tensioned after assembly. Since the base profiles 230, 240 and the head profiles 210, 220 are designed as Z-profiles, they are connected to the support elements 25 at their respective horizontal outer webs 26. This arrangement forms a self-supporting frame.

[0038] Both bottom profiles 230, 240 and both top profiles 210, 220 are also connected to each other via horizontally extending retaining elements 291 and / or base sections 292. In the embodiment shown here, the retaining elements 291 are connected to each other at the first ends 211, 221, 231, 241 and the second ends 212, 222, 232, 242. The Z-profile of the bottom profiles 230, 240 and top profiles 210, 220 enables at least a positive fit around the upper yoke 31 and the lower yoke 32.

[0039] The head section 21 and / or the base section 22 and / or the head profiles 210, 220 and / or the base profiles 230, 240 also have recesses 70, which enable a positive fit with the legs 33 of the core. The contour 72 of the recess 70 essentially corresponds to the profile of the respective leg 33.

[0040] As already explained, the head section 21 and / or the base section 23 can be formed in one piece and can also have recesses 70.

[0041] In Fig. Figure 5 shows a cross-sectional view in which the leg 33 and the two yokes 31, 32 are fixed in sections via the recesses 70 in a form-fitting manner. The contour 72 of the recess 70 adapts to the shape of the core 30. Additionally, a strip 71 is arranged between the core 30 and the frame 20. The strip 71 extends partially over the leg 33 and partially over the yokes 31, 32. It is adapted to the contour 72 of the recess 70. Furthermore, the strip 71 is adapted to the inner contour of the winding 40 and supports it. The strip 71 can be made of metal and / or plastic and / or composite materials. Preferably, each leg 33 is assigned a strip 71.

[0042] Spacers 55 are arranged between the frame 20 and the windings 40. These spacers 55 allow the windings 40 to rest against the frame 20, i.e., against the head section 21 and / or the bottom section 22 and / or the head profiles 210, 220 and / or the bottom profiles 230, 240. This ensures that the weight of the individual windings 40 is transferred to the frame 20 and not to the core 30. Thus, only the weight of the upper yoke 31, the individual legs 33, and the force FK of the core clamping elements 50 act on the lower yoke 32 of the core.

[0043] In Fig. Figure 6 shows the core clamping elements 50 and the winding clamping elements 60 of the transformer 1. The core clamping elements 50 for the core 30 are initially arranged between the inner webs 27 of the head profiles 210, 220 and the upper yoke 31. This configuration allows a defined force FK to act on the core 30, in particular on the yokes 31, 32 and the legs 33, via the frame 20. This defined force FK ensures that no excessive stresses are introduced into the core material of the core 30. This ensures the favorable energy efficiency of the core 30 of the transformer 1.

[0044] The winding tensioning elements 60 are arranged between the spacers 55, which rest on the windings 40, and the outer webs 26 of the head profiles 210, 220, or the head section 21. This design allows a precisely adjustable and defined force FW to act on the windings 40 via the frame 20. The required magnitude of this force FW depends on the construction of the windings 40 (e.g., loosely wound, glued or potted with resin, foil winding, wire winding) and on the required operating characteristics of the transformer 1. This force FW influences the short-circuit withstand capability of the transformer 1. Due to this arrangement, the weight forces of the windings 40 do not act on the lower yoke 32 but on the frame 20.

[0045] The adjustable force FW on the windings 40 is up to 16 times, often many times higher, than the force FK on the core 30. The force FW on the windings 40 can be several kN per winding (depending on the type or size of the transformer), for example up to 4 kN.

[0046] In the Fig. 7a and Fig. Figure 7b shows a winding clamping element 60. This can also be used as a core clamping element 50. The winding clamping element 60 is designed as a screw 61 with a thread and extends through the head part 21 or the head profiles 210, 220. A pressure piece 62 is arranged at a lower end 611 of the screw 60, which is positively engaged at the spacer 55. By screwing the screw 61 in or out, the force FW on the winding 40 is increased or decreased. When the winding clamping element 60 is used as a core clamping element 50, the force FK on the core 30 is increased or decreased by screwing the screw 61 in or out.

[0047] In the Fig. 8a and Fig. Figure 8b shows another winding clamping element 60. This can also be used as a core clamping element 50. The winding clamping element 60 is designed as a pressure bolt 63 with disc springs or clamping washers 64. The pressure bolt 63 is fixed in its upper region with a nut 65. At its lower end 611, the pressure bolt 63 is positively engaged at a distance 55. The disc springs or clamping washers 64 arranged between the head part 21 or the head profiles 210, 220 and the pressure bolt 63 are pre-tensioned and exert a force FW on the winding 40. The force FW on the winding 40 can be adjusted or preset as desired by varying the number of disc springs or clamping washers 64. At the same time, any existing dimensional tolerances of up to several mm are compensated for without exerting any force. When using the winding clamping element 60 as a core clamping element 50, the force FK on the core 30 is increased or reduced by the number of disc springs 64.

[0048] In the Fig. 9a and Fig. Figure 9b shows another winding clamping element 60. This can also be used as a core clamping element 50. The winding clamping element 60 is also designed as a pressure bolt 63, but with a compression spring 66. The pressure bolt 63 is fixed in its upper region by a snap ring 67. At its lower end 611, the pressure bolt 63 is also positively engaged at a distance 55. The compression spring 66, arranged between the head part 21 or the head profiles 210, 220 and the pressure bolt 63, is pre-tensioned and exerts a force FW on the winding 40. The force FW on the winding 40 can be adjusted as desired by the type and strength of the compression spring 66. When the winding clamping element 60 is used as a core clamping element 50, the force FK on the core 30 is increased or decreased by the type of compression spring 66. REFERENCE MARK 1 transformer 20 frames 21 Headboard 210 first head profile 211 first end of 210 212 second end of 210 220 second head profile 221 first end of 220 222 second end of 220 23 Base section 230 first soil profile 231 first end of 230 232 second end of 230 240 second soil profile 241 first end of 240 242 second end of 240 25 support element 251 Threaded rod 252 Spacer tube 253 Threaded rod section 26 outer bridge 27 inner bridge 28 Mother 291 Holding element 292 foot parts 30 core 31 upper yoke 32 lower yoke 33 thighs 331 inner block 332 outer block 40 turns 50 core clamping element 55 spacers 60 winding tensioning element 61 screw 611 lower end 62 printed piece 63 pressure bolts 64 Belleville washers / tensioning washers 65 Mother 66 compression springs 67 Snap ring 70 cutouts 71 strips 72 contour 80 axis A section D cross-section

Claims

[1] Transformer (1) comprising a core (30) with an upper yoke (31), a lower yoke (32) and at least one leg (33), at least one winding (40) arranged around the leg (33), a frame (20) with a bottom part (23) and a top part (21) and support elements (25) connecting the bottom part (23) to the top part (21), wherein the frame at least partially encloses the core (30) and the winding (40), at least one core clamping element (50) for applying a first force (FK) to the core (30) via the frame (20), at least one winding tensioning element (60) for applying a second force (FW) to the winding (40) via the frame (20), wherein the core clamping element (50) and the winding clamping element (60) are designed such that the first force (FK) and the second force (FW) can be adjusted independently of each other, the bottom part (23) comprises a first bottom profile (230) and a second bottom profile (240) and the head section (21) comprises a first head profile (210) and a second head profile (220), where the bottom profiles (230, 240) and the top profiles (210, 220) are designed as Z-profiles, and the first force (FK) and the second force (FW) are aligned parallel to each other and act against a vertical direction of the transformer (1), wherein the first head profile (210) and the second head profile (220) each have an inner web (27) and the core clamping element (50) is arranged between the respective inner web (27) and the upper yoke (31). [2] Transformer according to claim 1, wherein the first and second bottom profiles (210, 220) fix the lower yoke (33) in a form-fitting and / or force-fitting manner. [3] Transformer according to claim 1, wherein the first and second head profiles (210, 220) fix the upper yoke (31) in a form-fitting and / or force-fitting manner. [4] Transformer according to one of the preceding claims, wherein the core clamping element (50) is arranged between the upper yoke (31) and the head section (21) and / or the winding tensioning element (60) is arranged between the winding (40) and the head part (21). [5] Transformer according to one of the preceding claims, wherein the first head profile (210) and the second head profile (220) each have an outer web (26) and the winding tensioning element (60) is arranged between the respective outer web (26) and the winding (40). [6] Transformer according to any one of the preceding claims, wherein the first head profile (210) has a first end (211) and a second end (212), the second head profile (220) has a first end (221) and a second end (222), the head profiles (210, 220) are connected to each other at their respective first ends (211, 221) by at least one retaining element (291) and the head profiles (210, 220) are connected to each other at their respective second ends (212, 222) by at least one retaining element (291). [7] Transformer according to one of the preceding claims, wherein the first soil profile (230) has a first end (231) and a second end (232), the second soil profile (240) has a first end (241) and a second end (242), the soil profiles (230, 240) at their respective first ends (231, 241) by at least a retaining element (291) are connected to each other and the floor profiles (230, 240) are connected to each other at their respective second ends (232, 242) by at least one retaining element (291). [8] Transformer according to one of the preceding claims, wherein the head profiles (210, 220) are connected to the bottom profiles (230, 240) with at least four support elements (25) at their ends (211, 221, 212, 222). [9] Transformer according to one of the preceding claims, wherein the core clamping element (50) is designed as a screw (61) with pressure piece (62) and / or as a pressure bolt (63) with clamping washer (64) and / or as a pressure bolt (63) with compression spring (66). [10] Transformer according to one of the preceding claims, wherein the winding tensioning element (60) is designed as a screw (61) with pressure piece (62) and / or as a pressure bolt (63) with clamping washer (64) and / or as a pressure bolt (63) with compression spring (66). [11] Transformer according to one of the preceding claims, wherein the core (30) is made of an amorphous metal.

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