Transformer

Abstract

A transformer comprises: - a core (101), - a winding (102, 103) wound around a winding axis (105) extending along the core (101), - an eddy losses reducer (200), the eddy losses reducer (100) comprising a ring segment shape, being arranged at an axial end (106) of the winding (102, 103) and comprising a non-ferromagnetic main body (201) and a ferro-magnetic layer (202) surrounding the main body (201).

Description

[0001] P2023,1496 WO N / P230155WO01 November28,2024 -1 - Description Transformer The presentdisclosure relatesto atransformer,in particularto a transformer for application in power grid syst ems, forexample itrelatesto high voltage transformers. Transformersare used in powersystemsforvoltage levelcontrol. In particular, a transformer is used to st ep up andstep down voltage in electric power systems in orde r totransmitand utilize electricalpower.US 10658106 B2 relates to a safe stationary induc tionelectrical apparatus that prevents a fragment comin g off amagnetic shield, wound around an iron core leg port ion of thestationary induction electrical apparatus, due to v ibrationsfrom being released in a tank accommodating the sta tionaryinduction electricalapparatusand thuspreventsa trouble such asdielectricbreakdown.US 2018 / 358160 A1 relates to a stationary induction apparatusthat includes: an iron core; a winding wound outsid e of theiron core; a plurality of iron core clamps that san dwich thewinding from a longitudinal direction of the iron c ore; amagnetic material ring configured with a silicon st eel platewound outside of the iron core; a laminated magneti c materialcomposite ring thatincludesan insulatorprovided on anouter circumference of the magnetic material ring t hatincludes an electrical conductor provided on an out ercircumference of the insulator, and that is dispose d betweenthe winding and each of the iron core clamps; and a holding- P2023,1496 WO N / P230155WO01 November28,2024 -2 - and-cooling structure disposed between the winding and the laminated magneticmaterialcomposite ring.US 2011 / 316662 A1 relates to winding arrangement fo r atransformer or for a reactor. The winding arrangeme ntincludesan annularwinding coverpartdisposed on the frontface of a winding, wherein a side surface of the wi ndingcover part overlaps a front surface of the winding, whereinthe annular winding cover part is designed to be ma gneticallyconductive at least in a partial area and comprises a convexside surface facing awayfrom the winding. WO 2017 / 134040 A1 relatesto a shielding ring used forwindings of transformers for reducing the electrica l load atthe edgesofthe conductors.Such a shielding ring comprises an electricallyconductive layer.According to the invention,a combination of a polymer matrix and fillers as th eelectrically conductive layer are proposed, by mean s of whichcombination the resistance of the electrically cond uctivelayer of a shielding ring can be set exactly as nee ded andthus the correct resistance of the electrically con ductivelayer can be realized according to the application.It is desirable to provide a transformer that can b e operatedreliably.Embodiments of the disclosure relate to a transform er. Thetransformer comprises a core. The transformer compr ises awinding. The winding is wound around a winding axis extendingalong the core. The transformer comprises an eddy l ossesreducer.The eddylossesreducerisarranged atan axialendof the winding. The eddy losses reducer, in the fol lowingalso called “reducer”, comprises a non-ferromagneti c main P2023,1496 WO N / P230155WO01 November28,2024 -3 - body.The reducercomprisesa ferro-magneticlayer surrounding the main body.During operation, radial flux generate axial forces . Forexample, these forces cause vibration and resulting noises.In addition, radial flux leads to losses and hotspo ts. Theeddy losses reducer is arranged to reduce losses, h otspotsand thus also forces. Due to the eddy losses reduce r, themagnetic flux generated by the winding generates le ss eddylosses in conductors of the winding and thus less a xialforces as well. The eddy losses reducer is arranged at theaxial end, where radial flux is higher and tends to go outfrom the winding and reach the core or the tank. Th is isreduced by the eddy losses reducer. Thus, losses an d hotspotsgenerated by the radial flux at the end of the wind ing arereduced.The eddy losses reducer, which can also be called “ magneticfluxcollector”,isused to reduce the eddyradial lossesinthe winding and / or the exposed area of the core. Inparticular, the eddy losses reducer can an integral part ofan equipotential ring which is arranged at the axia l end ofthe winding.The equipotentialring isextended by an eddylosses reducing functionality. Therefore, the ferro magneticlayer is provided which surrounds the non-ferromagn etic mainbody. For example, the ferromagnetic layer comprise s iron oranotherferromagneticmetalormaterial.The eddy losses reducer comprises a ring segment sh ape.According to an embodiment, the eddy losses reducer comprisesan opening where two ends of the eddy losses reduce r arearranged opposite each otherand are arranged ata distancefrom each other. The eddy losses reducer is interru pted at P2023,1496 WO N / P230155WO01 November28,2024 -4 -the opening. For example, ring flows along the eddy lossesreducerare avoided.The ring segmentshape maybe circular orelliptic.According to embodiments, the ferromagnetic layer c omprises athickness between 50 µm and 9 cm. Other thicknesses arepossible, in particular between 25 µm and a few cen timeters.The thickness, for example, is measured along the w indingaxisortransverse to it.According to embodiments, the ferromagnetic layer c omprises ametal strip. For example, the metal strip is rolled aroundthe main body. For example, the metal strip compris es oneiron sheet or more iron sheets. For example, the me tal stripconsists of an iron sheet or a plurality of iron sh eets. Forexample,the iron sheetsare rolled around the non-ferromagnetic main body. For example, the metal str ipcomprises a thickness between 50 µm and 9 cm in a v erticaldirection ofthe metalstrip,wherebythe vertical directionis thinner than the two transverse directions, whic h arealigned perpendicular to the vertical direction. Fo r example,the iron sheet is made of ferromagnetic material. F orexample,the iron sheetcompriese electricalsteel like theone used to produce transformer cores and including amorphousones.According to embodiments, the transformer can compr ise anadhesive connection to fix the metal strip. For exa mple, theadhesive connection fixes the metal strip to the ma in body.The adhesive connection can be useful to restrict t hemovementof the metal strip during operation. The adhesive c onnectionis configured to reduce vibrations of the metal str ip, if P2023,1496 WO N / P230155WO01 November28,2024 -5 -needed. The metal strip, which is rolled around the mainbody,isglued to reduce vibrations.According to embodiments, the main body comprises a nelectrically insulating material. The main body is, forexample, made of a non-ferromagnetic electrically i nsulatingmaterial to not, or only insignificantly, influence themagnetic field generated by the winding. For exampl e, themain body comprises at least one of wood and plasti c. Forexample,the main bodyconsistsofatleastone of wood andplastic. For example, the main body is made of lami nated woodortransformerboard.According to embodiments, the eddy losses reducer c omprises acovering layer.The covering layersurroundstheferromagnetic layer. For example, the ferromagnetic layer isarranged between the covering layer and the main bo dy. Thecovering layer protects the ferromagnetic layer and / or formsan electrical insulation. Alternatively or in addit ion, thecovering layerisused to smooth the surface. Forexample,the covering layercomprisesatleast one ofpaper, textile, and plastic. For example, the cover ing layercomprisescrepe paper.According to embodiments, the covering layer compri ses acarbon layer and / or a further metallic layer. For e xample,the carbon layerand / orthe furthermetalliclayer isformedas a coating of the covering layer. The carbon laye r and / orfurther metallic layer faces the ferromagnetic laye r. Forexample, the covering layer comprises several layer s. Forexample, the covering layer comprises a paper layer , a carbonand / or metallic layer, and a further paper layer. F or P2023,1496 WO N / P230155WO01 November28,2024 -6 -example, the carbon layer and / or the further metall ic layeris used to keep the voltage of the eddy losses redu cer at adefined voltage during operation.According to embodiments, the winding is arranged d irectlyadjacent to and at a distance to the core. Thus, th e eddylossesreducerisarranged atthe winding which is arrangednearest to the core. For example, the eddy losses r educer isarranged at the winding with the smallest diameter.According to embodiments, the transformer comprises a furthereddy losses reducer. The further eddy losses reduce r isdesigned correspondingly to the eddy losses reducer , forexample. The further eddy losses reducer is arrange d at afurther axial end of the winding. The further axial end isarranged axially opposite the axial end. At both ax ial endsof the winding, a respective eddy losses reducer is arrangedto reduce eddy losses and / or collect the magnetic f lux atboth axialends.According to an embodiment, the transformer compris es aplurality of windings around the core. For example,respective eddy losses reducers are arranged on eac h of thewindings. According to a further embodiment, respec tive eddylossesreducersare arranged onlyon a partofthe windings.In particular, the respective eddy losses reducer i s arrangedon the windings, which are arranged facing the core . Forexample, windings that are arranged facing away fro m the coredo not have an eddy losses reducer. For example, th e eddylosses reducers are arranged on the windings with t hesmallest radii and not on windings with a larger ra dius whichare arranged furtherawayfrom the core. P2023,1496 WO N / P230155WO01 November28,2024 -7 -According to an embodiment, the eddy losses reducer s arearranged coaxially to the core. For example, the ed dy lossesreducers of the plurality of eddy losses reducers c omprises acommon centerin a ready-to-operate condition.For example, the centercorrespondsto the winding axis.According to an embodiment, the transformer compris es asecond core. The transformer comprises a second win ding woundaround a second winding axis extending along the se cond core.The transformer comprises a second eddy losses redu cer. Thesecond eddy losses reducer, for example, is designe dcorrespondingly to the first eddy losses reducer. T he secondeddylossesreducerisarranged atan axialend of the secondwinding. It is possible that one eddy losses reduce rsurrounds the first core and a second eddy losses r educersurrounds the second core. It is possible that a pl urality ofeddy losses reducers surrounds the first core and a furtherplurality of eddy losses reducers surrounds the sec ond core.It is possible that respective eddy losses reducers arearranged on both axialendsofthe windingsaround the firstcore, or at just one single axial end. Alternativel y or inaddition, it is possible that respective second edd y lossesreducers are arranged at both axial ends of the sec ondwindings around the second core, or at just one sin gle axialend ofthe second windings.All of the features and advantages as described her einrelating to the eddylossesreducerare applicable to furthereddy losses reducers. For example, the winding is a primarywinding or a secondary winding. For example, the tr ansformercomprises a tertial winding, which is arranged with out aneddylossesreducer. P2023,1496 WO N / P230155WO01 November28,2024 -8 - Forexample,the voltage ratingsofone ormore of thewindings of the transformer are above 1 kV such tha t thevoltage ratings of all of the windings of the trans former areabove 1 kV.Hereinafter, the transformer will be explained in m ore detailwith reference to the drawings on the basis of exem plaryembodiments.The accompanying figuresare included to providea further understanding. In the figures, elements o f the samestructure and / or functionality may be referred by t he samereference signs. It is to be understood that the em bodimentsshown in the figures are illustrative representatio ns and arenot necessarily drawn to scale. Insofar as elements orcomponents correspond to one another in terms of th eirfunction in different figures, the description ther eof is notnecessarily repeated for each of the following figu res.Figure 1 shows a schematic cross-section of a trans formeraccording to an embodiment.Figures 2 to 4 show different views of an eddy loss es reduceraccording to an embodiment.Figure 1 schematically shows parts of a transformer 100. Thetransformer 100 is enclosed in a tank (not explicit ly shown)which, for example, is filled with a dielectric flu id. Thetransformer 100 comprises a first core 101 and a se cond core121. Windings 102, 103, 104 are arranged around the firstcore 101. Further windings 122, 123, 124 are arrang ed aroundthe second core 121.In particular,the firstcore 101 andthe windings 102, 103, 104 are symmetric around a w indingaxis105.Correspondingly,the second core 121 and the P2023,1496 WO N / P230155WO01 November28,2024 -9 -windings 122, 123, 124 are symmetric around a secon d windingaxis125. The winding 102 extendsalong the winding axis105 andterminates in an axial end 106 and an opposite axia l end 107.The winding 103 ends in an axial end 108 and an opp ositeaxial end 109. The windings 122 and 123 correspondi nglyterminate in respective axial ends 126, 127, 128, 1 29.The winding 102 has a smaller diameter than the rem ainingwindings 103, 104, which are arranged around the fi rst core101. The coil 102 is located closest to the first c ore 101.The winding 102 isarranged ata distance 150 from the first core 101.The windings 122 has a smaller diameter than the re mainingwindings 123, 124, which are arranged around the se cond core121.The coil122 islocated closestto the second core 121.The transformer 100 comprises an eddy losses reduce r 200which is arranged at the axial end 106 of the windi ng 102.Further eddy losses reducers 200 are arranged at th e axialends 107, 108, 109 around the first core 101. Aroun d thesecond core 121 eddy losses reducers 200 are arrang ed at theaxialends126,127,128 and 129.For example, no eddy losses reducers 200 are arrang ed at thewinding 104 and the winding 124.Thus,the winding 104 aroundthe first core 101 has no associated eddy losses re ducer 200.Thus, the winding 124 around the second core 121 ha s noassociated eddylossesreducer200. P2023,1496 WO N / P230155WO01 November28,2024 -10 -Eddy losses reducers 200 are arranged at the windin gs 102,103 that are arranged radially between the first co re 101 andthe winding 104.Eddy losses reducers 200 are arranged at the windin gs 122,123 that are arranged radially between the second c ore 121and the winding 124.The number of eddy losses reducers 200 is purely ex emplaryand maydeviate from the numbershown in Figure 1. Forexample, less than the shown eddy losses reducers 2 00 may beprovided or more. For example, just one single eddy lossesreducer200 isprovided around each core 101,121.Respective eddy losses reducers 200 can be arranged at eachopposite end or only at one end and the other end i s free ofan eddy losses reducer. The number of eddy losses r educers200 around core 101 can be different from the numbe r of eddylossesreducers200 around the second core 121.It ispossible that the transformer 100 comprises more th an twocores 101, 121, for example three cores with respec tivewindingsormore.Forexample,the transformer100 comprisesthree cores with respective windings and 12 eddy lo ssesreducers 200, four eddy losses reducers 200 per cor e, twowindings with two eddy losses reducers 200 each per core.As shown in Figure 2, the eddy losses reducer 200 c omprises aring-like shape 203. The eddy losses reducer 200 co mprises acenter 213. For example, the center 213 of the shap e 203 ofthe eddy losses reducer 200 lies on the winding axi s 105 orthe winding axis125 respectively.The eddylosses reducer 200 extendsin the ring-like shape orring segment shape 203around the respective core 101, 121. For example, t he eddy P2023,1496 WO N / P230155WO01 November28,2024 -11 -losses reducer comprises a radius around the center 213 witha value between 30 cm and 3 meters, depending on th etransformertype ofthe transformer100.The eddy losses reducer 200 for example is not form ed as aclosed ring but with the ring segment shape 203. Th e eddylosses reducer 200 comprises an opening 204. At the opening204 two ends 205, 206 of the eddy losses reducer 20 0 arearranged facing each other and opposite each other. the twoends 205, 206 are arranged at a distance 207. For e xample,the distance 207 comprises values from 0.5 mm to 25 cm. Otherranges and values for the distance 207 are possible .Figure 3 shows a cross-section of the eddy losses r educer 200along the line A of Figure 2. The eddy losses reduc er 200comprises a main body 201. The main body 201 compri ses thering segment shape 203. The main body 201 comprises orconsists of a non-ferromagnetic material. For examp le, themain body is made out of wood and / or plastic. In pa rticular,the main body 201 is made out of laminated wood and / ortransformerboard.The main body201 isconfigured asa stable bodywhich supportsthe eddylossesreducer 200. A firstlayer202 surroundsthe main body201.The first layer202 comprisesorconsistsofa ferromagnetic material.In particular, the first layer 202 comprises or con sists of ametal, for example a metal strip 209 (Figure 4). Fo r example,the first layer 202 comprises iron or consists of i ron. Forexample, the first layer 202 is an iron sheet and c an just bemade of ferromagnetic material. For example, the fi rst layer202 comprises electrical steel like the one used to producetransformercoresand including amorphousones. P2023,1496 WO N / P230155WO01 November28,2024 -12 -An optional further layer 212 surrounds the first l ayer 202.The further layer 212 comprises or consists of a ca rbon layerand / or a further metallic layer. In particular, the furtherlayer 212 comprises an electrically conductive mate rial.A covering layer 211 surrounds the further layer 21 2 and thefirst layer 202. For example, the covering layer co mprises orconsists of paper, textile or plastic. For example, thefurtherlayer212 coversthe covering layer211 at a surfacewhich faces the first layer 202. For example, the c overinglayer211 comprisescarbonized papersuch thatthe further layer212 isa carbon layeron the paper.Figure 4 shows an example of the eddy losses reduce r 200 inwhich the ferromagnetic layer 202 is made out of th e metalstrip 209.The metalstrip 209 iswound around the main body 201,such thatthe metalstrip 209 coversthe main body201.For example, a plurality of metal strips 209 is wou nd aroundthe main body 201 to achieve a desired thickness 20 8 (Figure3) of the ferromagnetic layer 202. Alternatively or inaddition, the metal strip 209 is wound around the m ain body201 severaltimesto achieve the desired thickness 208.Forexample, the thickness 208 comprises a value betwee n 50 µmand 9 cm,forexample between 1 mm and 10 mm.For example, the metal strip 209 comprises a thickn essbetween 0.01 mm and 0.6 mm .In particular,ifthe metalstrip 209 comprises amorphous materials, the thickn ess of themetal strip comprises a value between 10 and 15 µm. Forexample, the metal strip 209 is a rolled iron sheet .According to an example, the metal strip 209 is fix ed by anadhesive connection 210. P2023,1496 WO N / P230155WO01 November28,2024 -13 -According to another example, the adhesive connecti on 210 isomitted.The adhesive connection 210 can glue the metal stri p layer209 to itself and / or to the main body 201. An adhes ive fixesthe metal strip layer 209. Thus, a vibration of the metalstrip 209 can be reduced, if needed depending on th e design.Thisreducesnoise emissions.According to an embodiment, the eddy losses reducer 200 alsoserves as an equipotential ring to reduce electrica l stressat the axial ends 106 to 109, 126 to 129 of the res pectivewindings 102, 103, 104, 122, 123, 124. Thus, no add itionalelement in addition to an equipotential ring is nec essary toachieve the reduction of the eddy radial losses wit h the eddylosses reducer 200. The eddy losses reducer 200 act s as theequipotential ring and as a magnetic shunt. Transfo rmer eddylossescan be easilyreduced.Byreducing the eddy losses, the efficiencyofthe transformer100 isimproved. Due to thereduced eddy losses, material savings can be achiev ed.The iron used for the metal strip 209 for example c omprisesan amorphous iron. For example, the iron used for t he metalstrip 209 is of the same type of iron as used for t he core101,102. The eddylossesreducer200 issimple to implement andachieves lower losses and / or lower forces in the tr ansformer.The material requirements for the eddy losses reduc er 200 arereduced compared to other solutions. Efficiency andreliability of the transformer 100 can be increased without P2023,1496 WO N / P230155WO01 November28,2024 -14 -any need for a substantive design change of the tra nsformer100.

[0002] P2023,1496 WO N / P230155WO01 November28,2024 -15 - Reference Signs 100 transformer 101 core 102,103,104 winding 105 winding axis 106,107,108,109 axialend 121 core 122,123,124 winding 125 winding axis 126,127,128,129 axialend 150 distance 200 eddylossesreducer 201 main body 202 ferro-magneticlayer 203 ring segmentshape 204 opening 205,206 end 207 distance 208 thickness 209 metalstrip 210 adhesive connection 211 covering layer 212 carbon layerand / orfurthermetalliclayer 213 center

Claims

P2023,1496 WO N / P230155WO01 November28,2024 -16 - Claims 1.A transformer,comprising: -a core (101), -a winding (102,103)wound around a winding axis (105) extending along the core (101),- an eddy losses reducer (200), characterized in th at theeddylossesreducer(100)comprisesa ring segment shape,isarranged at an axial end (106) of the winding (102, 103) andcomprises a non-ferromagnetic main body (201) and a ferro-magnetic layer (202) surrounding the main body (201 ).

2. Transformer according to claim 1, wherein the ed dy lossesreducer(200)comprisesa ring segmentshape (203) and anopening (204) where two ends (205, 206) of the eddy lossesreducer(200)are arranged opposite each otherand are arranged ata distance (207)from each other.

3. Transformer according to any one of the precedin g claims,wherein the ferro-magneticlayer(202)comprisesa thickness (208)between 50 μm and 9 cm.

4. Transformer according to any one of the precedin g claims,wherein the ferro-magneticlayer(202)comprisesa metalstrip (209) which is rolled around the main body (2 01).

5. Transformer according to claim 4, wherein eddy l ossesreducer (200) comprises an adhesive connection (210 ) to fixthe metalstrip (210).

6. Transformer according to any one of the precedin g claims,wherein the main body (201) comprises an electrical lyinsulating material.P2023,1496 WO N / P230155WO01 November28,2024 -17 -7. Transformer according to any one of the precedin g claims,wherein the main body(201)comprisesatleastone ofwood, and plastic.

8. Transformer according to any one of the precedin g claims,eddy losses reducer (200) comprises a covering laye r (211)which surroundsthe ferro-magneticlayer(202).

9. Transformer according to claim 8, wherein the co veringlayer (211) comprises at least one of paper, textil e, andplastic. 10.Transformeraccording to claim 8 or9,wherein thecovering layer (211) comprises a carbon layer (212) and / or afurthermetalliclayer(212).

11. Transformer according to any one of the precedi ng claims,wherein the winding (102) is arranged directly adja cent toand ata distance (150)to the core.

12. Transformer according to any one of the precedi ng claims,comprising a further eddy losses reducer (200), whe rein thefurthereddylosses(200)reducerisarranged ata furtheraxial end (107) of the winding (102), wherein the f urtheraxial end (107) is arranged axially opposite the ax ial end(106).

13. Transformer according to any one of the precedi ng claims,comprising a pluralityofwindings(102,103,104) around thecore (101), wherein a respective eddy losses reduce r (200) isarranged on each of at least the windings (102, 103 ) of aP2023,1496 WO N / P230155WO01 November28,2024 -18 -part of the windings (102, 103, 104) which is arran ged facingthe core (101). 14.Transformeraccording to claim 13,wherein the eddylosses reducers (200) are arranged coaxially to the core.

15. Transformer according to any one of the precedi ng claims,comprising a second core (121), a second winding (1 22) woundaround a second winding axis(125)extending along the secondcore (121), and a second eddy losses reducer (200), thesecond eddylossesreducer(200)being arranged at an axial end (126)ofthe second winding (122).

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