On-load tap changer, transformer and operating method

Abstract

In one embodiment, the on-load tap changer (1) is f or a distribution transformer (10) and comprises: - a driving system (2) including a force store unit (31), - a slow-moving selector contact package (4), and - a fast-moving selector contact package (5), wherein - the driving system (2) is to move the slow-moving selector contact package (4) with a first speed and the fast -moving selector contact package (5) with a second, higher speed from a first selector contact (11) to a second selector contact (12) of the transformer (10), - the driving system (2) is to begin movement of the fast-moving selector contact package (5) later than movement of the slow-moving selector contact package (4), and - the force store unit (31) is loaded during movement of the slow-moving selector contact package (4) and is unloaded to drive movement of the fast-moving selector contact package (5).

Description

[0001] P2024,0483 WO N / P230263WO01 May5,2025 -1 - DescriptionOn-load tap changer, transformer and operating meth odAn on-load tap changer and a transformer comprising such anon-load tap changer are provided. An operating meth od forsuch a transformerisalso provided.Documents US 2023 / 0230786 A1, US 2023 / 0230781 A1, W O2023 / 001962 A1 and WO 2018 / 148812 A1 refer to compo nents foron-load tap changers.A problem to be solved is to provide a compact on-l oad tapchanger. Thisobjectisachieved,interalia,byan on-load tapchanger, a transformer and an operating method as d efined inthe independent claims. Exemplary further developme ntsconstitute the subject-matter of the dependent clai ms.For example, the on-load tap changer, OLTC for shor t, is fora transformer, like a distribution transformer, and has aslow-moving selector contact package and a fast-mov ingselector contact package configured to be moved wit h a higherspeed than the slow-moving selector contact package . Thefast-moving selectorcontactpackage isconfigured to startmoving after the slow-moving selector contact packa ge. Whenthe OLTC performs switching, both the slow-moving a nd thefast-moving selector contact package move from a fi rstselector contact to a second selector contact of th etransformer. P2024,0483 WO N / P230263WO01 May5,2025 -2 -Thus, a design of an on-load tap changer for uninte rruptedswitching between different winding taps of a trans former canbe provided.With itsreduced dimensionsitcan beimplemented in small distribution transformers. For example,the OLTC uses a linear movement design for uninterr uptedswitching between the differentwinding taps.For example, two pairs of moving selector contacts’ packagesare presentforeach electricphase which,when in a switching cycle,execute linearmotion and connect to thenext pair of the fixed selector contacts. Moving co ntactspackages can thus be supported with linear guidance . Movingselector contacts’ packages are electrically connec tedthrough sliding via linearconductorsto switching meanswhich are, for example, vacuum interrupters. For ea ch on-loadtap changerphase,inputmotion from a motordrive isseparated to a slow-motion driving transmission and to afast-motion driving transmission. Slow motion drivi ngtransmission is charging a force store unit in a dr ivingmechanism and, for example, a screw threaded spindl e driveslinearly a slow-motion movable contacts’ package to theadjacent fixed selector contact. When driving the s low-movingcontacts’ package, another force store unit, for ex ample,between the slow-motion contacts’ package and the f ast-motioncontacts’package,startitscharging. When the force store unitin the driving mechanism is unlocked,itactuatesthe fast-motion transmission fordriving the switching means and driving unlocking a rms forthe force-store unitbetween slow-motion contacts’ packageand the fast-motion contacts’ package, for example. When thefast-motion contacts’ package is unlocked, it is dr iven to P2024,0483 WO N / P230263WO01 May5,2025 -3 - the adjacentfixed selectorcontact,thusaligning with the previouslyswitched slow-motion contacts’package.In at least one embodiment, the on-load tap changer , OLTC, isconfigured fora transformer,like a distribution transformer,and comprises:- a driving system including a first force store un it,-a slow-moving selectorcontactpackage,and -a fast-moving selectorcontactpackage, wherein- the driving system is configured to move the slow -movingselector contact package with a first speed and the fast-moving selector contact package with a second speed from afirst selector contact of the transformer to a seco ndselector contact of the transformer, the second spe ed ishigherthan the firstspeed,- the driving system is further configured to begin movementof the fast-moving selector contact package later t hanmovement of the slow-moving selector contact packag e, and- the first force store unit is loaded during movem ent of theslow-moving selector contact package and is unloade d to drivemovement of the fast-moving selector contact packag e.According to at least one embodiment, the OLTC is a one-phaseOLTC. Otherwise, the OLTC can be a multi-phase OLTC , like athree-phase OLTC.Forsimplicity,in the following referenceis made to a one-phase OLTC unless indicated otherw ise, butthe statements below apply analogously for a multi- phaseOLTC.According to at least one embodiment, the second sp eed is atleast twice or at least five times the first speed.Alternativelyoradditionally,the second speed is atmost P2024,0483 WO N / P230263WO01 May5,2025 -4 -hundred times or at most twenty times the first spe ed. Thefirst and second speed may refer to an average spee d of therespective package from the firstselectorcontact to thesecond selector contact, that is, to a distance bet ween therespective positions of the packages divided by the timerequired forthe overallmovement.According to at least one embodiment, the driving s ystemfurther comprises a first shaft coupled to the slow -movingselector contact package. For example, the first sh aft is ascrew-threaded spindle. By means of the first shaft ,especially by rotating the first shaft, the slow-mo vingselectorcontactpackage isdriven,thatis,moved between the selectorcontacts.According to at least one embodiment, the driving s ystemfurthercomprisesa second shaft.Forexample,the secondshaft is also coupled to the slow-moving selector c ontactpackage. This means, for example, that the second s haft isled through the slow-moving selector contact packag e.However, the second shaft may not need to exert dri ving forceon the slow-moving selector contact package to move thelatter.According to at least one embodiment, the second sh aftincludes one or a plurality of cam profiles. The at least onecam profile, or at least one of the cam profiles, i sconfigured to trigger a movement of the fast-moving selectorcontactpackage.Forexample,upon rotation ofthe secondshaft, a tongue of the cam profile interacts with p art of thedriving system atthe fast-moving selectorcontact package. Forexample,bymeansofthe cam profile the first force store unitcan be released. P2024,0483 WO N / P230263WO01 May5,2025 -5 -According to at least one embodiment, the slow-movi ngselector contact package comprises one or a plurali ty ofunlocking arms. For example, the at least one unloc king armis coupled to the second shaft. This means, for exa mple, thatthe at least one unlocking arm is either directly a cted bythe second shaft or that a movement of the at least oneunlocking arm istriggered bythe second shaft.It ispossible that the at least one unlocking arm is not coupledto the firstshaft.According to at least one embodiment, the unlocking arm isconfigured to unlock the first force store unit aft er beingcharged by the movement of the slow-moving selector contactpackage, the charging is done by rotation of the fi rst shaft.Forexample,the firstforce store unitischarged bymovingthe slow-moving selector contact package by means o f thefirst shaft, and then discharging of the first forc e storeunit is triggered via the unlocking arm by means of thesecond shaft.According to at least one embodiment, the driving s ystemfurthercomprisesone ora pluralityofmotors.By meansofthe at least one motor, the first shaft may be driv en. It ispossible that the first shaft is the only component of thedriving system to be directlydriven bythe motor. Forexample, the second shaft is coupled to the first s haft by adriving mechanism so that movement of the second sh aft isdetermined bythe firstshaft.According to at least one embodiment, the driving s ystemfurther comprises a second force store unit. For ex ample, thesecond force store unit is located at or next to an end of P2024,0483 WO N / P230263WO01 May5,2025 -6 -the first shaft and is charged via the driving mech anism byrotation of the first shaft. Thus, the motor can beconfigured to directly drive the first shaft and to load thesecond force store unit during movement of the slow -movingselectorcontactpackage.According to at least one embodiment, the second fo rce storeunit is unloaded upon arrival of the slow-moving se lectorcontact package at the second selector contact to d rive thesecond shaft. For example, the second force store u nit iscoupled to a Geneva drive that acts on the second s haft. Thatis, by means of the second force store unit the Gen eva drivecan rapidlybe acted when the slow-moving selector contactpackage is at the right position. Thus, by means of thesecond force store unit the second shaft can be mov ed andconsequentlythe discharging the firstforce store unitcan be triggered. According to atleastone embodiment,the rotation ofthesecond shaft releases the unlocking arm. Hence, the secondforce store unit may drive the Geneva drive or a si milarmeans,then rotatesthe second shaft,releasesthe unlockingarm and triggers unloading the first force store un it so thatthe fast-moving selector contact package starts mov ing.According to at least one embodiment, the OLTC furt hercomprises a collector rail as power output line. Fo r example,the collector rail is split into a first electric c ollectorrail and a second electric collector rail. The elec triccollector rails may briefly be referred to as colle ctors. Forexample,the collectorslead to a neutralterminal ofthe transformer.Correspondingly,the selectorcontact maylead to a line terminal. P2024,0483 WO N / P230263WO01 May5,2025 -7 -According to at least one embodiment, the slow-movi ngselectorcontactpackage isguided along the first electriccollector rail and the fast-moving selector contact packageis guided along the second electric collector rail. Forexample, the electric collector rails run in parall el witheach other. It is possible that there are further r ails forguidance of the slow-moving and / or fast-moving sele ctorcontact packages. Possibly, the second electric col lectorrailmaybe splitinto two sub-rails.According to at least one embodiment, the first for ce storeunit is mechanically coupled to the fast-moving sel ectorcontact package. For example, the first force store unitcomprises to end plates between which a spring is m ounted asthe first force store unit. The fast-moving selecto r contactpackage may be placed between the end plates and th e firstforce store unit may run through the fast-moving se lectorcontactpackage. According to atleastone embodiment,trajectories oftheslow-moving selector contact package and of the fas t-movingselector contact package run collinearly. Especiall y, thetrajectories run along parallel straight lines. How ever,othertrajectoriesare possible aswell.According to at least one embodiment, the driving s ystem isconfigured to start the movement of the fast-moving selectorcontact package upon arrival of the slow-moving sel ectorcontact package at the second selector contact. Thu s, it ispossible that firstly only the slow-moving selector contactpackage moves and that then only the fast-moving se lectorcontact package moves. In other words, the slow-mov ing and P2024,0483 WO N / P230263WO01 May5,2025 -8 - the fast-moving selectorcontactpackagesmaymove sequentiallybutnotsimultaneously.According to at least one embodiment, the driving s ystemfurther comprises one or a plurality of auxiliary r ails. Forexample, the at least one auxiliary rail is assigne d to thefast-moving selector contact package only and not t o theslow-moving selectorcontactpackage.According to at least one embodiment, the fast-movi ngselector contact package and the auxiliary rail are providedwith a mutual mechanical interlock. For example, at theauxiliary rail there are distinct interlock positio nsassociated in a one-to-one manner with positions of the firstselector contact and the second selector contact, s een alongthe auxiliary rail. Thus, by means of the interlock s thefast-moving selectorcontactpackage maysnap onto theinterlock positions and consequently at the selecto r contactpositions. For example, the auxiliary rail comprise s a gridor pattern corresponding to the selector contact po sitions.According to at least one embodiment, the fast-movi ngselector contact package and the slow-moving select or contactpackage each comprise one or a plurality of contact clamps.The at least one contact clamp per package is confi gured toelectrically contact the first selector contact and thesecond selector contact at respective static positi ons of thefast-moving selector contact package and the slow-m ovingselectorcontactpackage.Thatis,atthe selector contact positionsthe packagesmayclamp onto the selector contacts. Between the selectorcontact,there maynotbe any clamping to a line terminalofthe transformer.A length of the clampsalong a direction of movement of the packages durin g P2024,0483 WO N / P230263WO01 May5,2025 -9 -switching is, for example, at most 30% or at most 2 0% or atmost 10% of a distance between adjacent ones of the selectorcontacts.A transformer additionally provided. The transforme rcomprises one or a plurality of the OLTCs as indica ted inconnection with at least one of the above-stated em bodiments.Features of the transformer are therefore also disc losed forthe OLTC and vice versa.In at least one embodiment, the transformer compris es an OLTCand a firstselectorcontactand a second selector contact being electricallyconnected with a winding ofthe transformer,forexample,via switching meanslike vacuum interrupters.During changing the selectorcontact bymeans ofthe OLTC,the firstand / orthe selectorcontact maybedisconnected from the winding using the switching m eans. Thefirst selector contact and a second selector contac t areassigned in a one-to-one manner to different windin g taps ofthe winding.For example, the first and second selector contacts arearbitraryadjacentselectorcontactschosen from a pluralityof the transformer’s selector contacts. By way of e xample,overall the transformer comprises at least two or a t leastfive and / or at most 30 or at most twelve of the sel ectorcontacts. Each one of the selector contacts is assi gned toexactly one of the winding taps. It is possible tha t all theselectorcontactsare ofa same design.According to at least one embodiment, the transform er is adistribution transformer. For example, the transfor mer isconfigured for a maximum electric load of at most 5 MVA or at P2024,0483 WO N / P230263WO01 May5,2025 -10 -most 1 MVA or at most 0.2 MVA. Alternatively or add itionally,the transformer is configured for a maximum electri c load ofatleast10 kVA oratleast100 kVA.According to at least one embodiment, the first sel ectorcontact and the second selector contact each compri se a firstterminal and a second terminal. For example, the fi rst andsecond terminalsofa specificone ofthe selector contacts are ata same electricpotential.Forexample,the firstand second terminalsare differentendsofa metalbar comprised bythe respective one ofthe selectorcontacts.According to at least one embodiment, the first ter minals areelectricallycontacted bymeansofthe slow-moving selectorcontact package. Alternatively or additionally, the secondterminals are electrically contacted by means of th e fast-moving selector contact package. Thus, also in case that onlyone ofthe packagesiscontacted with the firstor secondterminals, respectively, the associated winding tap iselectrically connected by the OLTC. Except for a sh ort periodof time during movement of the slow-moving and / or f ast-movingselectorcontactpackage,forexample,onlyone of the selectorcontactsiselectricallyconnected bythe OLTC.According to at least one embodiment, the transform er furthercomprisesa firstelectricswitch elementand / ora secondelectric switch element. The switch elements are, f orexample, vacuum interrupters. It is possible that t he firstand / or second switch elements are part of the OLTC; however,the first and / or second switch elements may also becomponents not exclusively used by the OLTC so that thesecomponents may not be regarded as part of the OLTC. P2024,0483 WO N / P230263WO01 May5,2025 -11 -According to at least one embodiment, the transform er furthercomprisesa resistorpackage and / ora preventiveautotransformer. By means of the resistor package a nd / or apreventive autotransformer, current limitation and / or voltagelimitation can be achieved during tap change. According to atleastone embodiment,the resistor package and the preventive autotransformerare assigned to the secondelectric switch element only and not to the first e lectricswitch element. Thus, only when the second electric switchelement is in an electrically conductive state, tha t is, isclosed,the resistorpackage and / ora preventive autotransformerare used.According to at least one embodiment, the first ele ctricswitch element is directly assigned to the winding. Forexample, it is possible that the first electric swi tchelement is the only active electric component betwe en thewinding and the selectorcontacts.According to at least one embodiment, the second el ectricswitch element is configured to be closed upon move ment ofthe fast-moving selectorcontactpackage.Thatis, currentflows through the resistor package and / or the preve ntiveautotransformer only upon movement of the fast-movi ngselector contact package is triggered and as long a s thefast-moving selector contact package is in movement .In otherwords,with beginning the movementofthe fast-moving selector contact package the second electric switchelement is closed and with ending said movement the secondelectric switch element is opened. For example, onl y directlyat the beginning of said movement and directly at t he ending P2024,0483 WO N / P230263WO01 May5,2025 -12 - ofsaid movementthe firstand the second electric switchelement are closed, that is, are in a conductive st ate.According to at least one embodiment, the first ele ctricswitch element is configured to be opened only when thesecond electricswitch elementisclosed.Thatis, the first electricswitch elementonlyopensduring movement ofthe fast-moving selectorcontactpackage.An operating method for the transformer is addition allyprovided.Bymeansofthe method,a transformeras indicatedin connection with at least one of the above-statedembodiments is operated. Features of the transforme r aretherefore also disclosed for the method and vice ve rsa.In at least one embodiment, the operating method is foroperating a transformer, like a distribution transf ormer, andcomprisesthe following steps,forexample,in the stated order:- optionally, receiving an instruction to switch be tween thedifferentwinding taps,- upon receiving the optional instruction, disconne cting theslow-moving selector contact package from the first selectorcontact and moving the slow-moving selector contact packageto the second selector contact, and charging the fi rst forcestore unit, -upon arrivalofthe slow-moving selectorcontact package atthe second selector contact, contacting the slow-mo vingselector contact package with the second selector c ontact andunloading the first force store unit so that the fa st-movingselector contact package is disconnected from the f irstselector contact and so that movement of the fast-m ovingselectorcontactpackage isinitiated,and P2024,0483 WO N / P230263WO01 May5,2025 -13 - -upon arrivalofthe fast-moving selectorcontact package atthe second selector contact, contacting the fast-mo vingselector contact package with the second selector c ontact.An on-load tap changer,OLTC,a transformerand an operatingmethod described herein are explained in greater de tail belowby way of exemplary embodiments with reference to t hedrawings. Elements which are the same in the indivi dualfigures are indicated with the same reference numer als. Therelationships between the elements are not shown to scale,however, but rather individual elements may be show nexaggeratedlylarge to assistin understanding. In the figures:Figure 1 is a schematic top view of an exemplary em bodimentofan OLTC described herein,Figure 2 is a schematic top view of an exemplary em bodimentofa transformercomprising an OLTC described herein,Figures 3 to 5 are schematic perspective views of a nexemplaryembodimentofan OLTC described herein with the slow-moving and the fast-moving selector contactpackage being both atthe firstselector contact,Figures 6 to 9 are schematic perspective views of t he OLTC ofFigures3 to 5 with the fast-moving selector contactpackage stillbeing atthe firstselector contactwhile the slow-moving selectorcontact package being atthe second selectorcontact, P2024,0483 WO N / P230263WO01 May5,2025 -14 -Figure 10 is a schematic representation of a circui t diagramofan exemplaryembodimentofan OLTC described herein,Figure 11 is a schematic block diagram of an exempl aryembodimentofan operating method forOLTCs described herein,andFigure 12 is a schematic view of an exemplary embod iment of atransformercomprising a pluralityofOLTCs described herein. Figure 1 illustratesan exemplaryembodimentofan on-loadtap changer 1, OLTC for short, for a transformer 10 . The OLTC1 comprises a driving system 2 that includes a firs t forcestore unit 31. For example, the first force store u nit 31includes a spring for storing a mechanical energy a nd forexerting mechanicalforce upon being released.Moreover, the OLTC 1 includes a slow-moving selecto r contactpackage 4 and a fast-moving selector contact packag e 5. Thedriving system 2 is configured to move the fast-mov ingselector contact package 5 with a higher speed than the slow-moving selector contact package 4 from a first sele ctorcontact 11 of a transformer 10 to a second selector contact12 of the transformer 10. For example, the fast-mov ingselector contact package 5 needs as most half the t ime or atmost a fifth of the time from the first 11 to the s econdselectorcontact12 asrequired bythe slow-moving selectorcontact package 4. The first and second selector co ntacts 11,12 are assigned to different winding taps of the tr ansformer10. P2024,0483 WO N / P230263WO01 May5,2025 -15 -The driving system 2 is further configured to begin amovement of the fast-moving selector contact packag e 5 to thesecond selector contact 12 later than a movement of the slow-moving selector contact package 4 to the second sel ectorcontact 12. The first force store unit 31 is loaded duringthe movement of the slow-moving selector contact pa ckage 4 tothe second selector contact 12. The first force sto re unit 31is unloaded to drive the movement of the fast-movin g selectorcontact package 5 when the slow-moving selector con tactpackage 4 reachesthe second selectorcontact12.For example, the slow-moving selector contact packa ge 4 isguided along a first shaft 21. Optionally, the fast -movingselector contact package 5 may be guided along an a uxiliaryrail23.In Figure 2, the transformer 10 comprising the OLTC 1 isillustrated. The transformer 10 further comprises t he firstselector contact 11 and the second selector contact 12. Theseselector contacts 11, 12 are two adjacent ones of a pluralityof selector contacts 19 of the transformer 10. Each one ofthe selector contacts 19 is assigned to one winding tap of awinding 17 ofthe transformer10.With the OLTC 1, switchingbetween the selector contacts 19 and, thus, between thewinding taps is enabled. The selector contacts 19 c ould bedistributed along the first shaft 21 in an equidist antmanner. Optionally,the transformer1 includesa first151 and asecond electric switch element152, like vacuum inte rrupters.The electric switch elements 151, 152 may be part o f the OLTC1. The transformer 1 may have a source line 18 supp lying the P2024,0483 WO N / P230263WO01 May5,2025 -16 -winding 17 with electric power and an electric coll ector 6outputting the electric power at a different voltag e.Otherwise, the same as to Figure 1 may also apply t o Figure2,and vice versa.In Figures 3 to 9, an exemplary embodiment of the O LTC 1 isshown in more detail.In thisregard,Figures3 to 5 refertothe OLTC 1 with both the slow-moving 4 and the fast -movingselector contact package 5 being at the first selec torcontact 11, while Figures 6 to 9 show the situation with thefast-moving selectorcontactpackage 5 stillbeing atthefirst selector contact 11 and the slow-moving selec torcontact package 4 already having moved the second s electorcontact12. In thisembodimentofFigures3 to 9,the packages 4,5 eachcomprise contact clamps 41, 51 which clamp onto the selectorcontacts 11, 12, 19. It is possible that the contac t clamps41, 51 are always in a closed state so that the con tactclamps 41, 51 slide off and onto the selector conta cts 11,12,19 when the packages4,5 move.The driving system 2 comprises the first shaft 21 a nd a motor27. For example, the slow-moving selector contact p ackage 4is driven by the first shaft 21 which comprises, fo r example,a screw threaded spindle. That is, when the first s haft 21rotates, the package 4 moves forward or backward, d ependingon a direction of rotation of the first shaft 21. T he firstshaft21 isdriven bythe motor27.Itispossible thatthe firstshaft21 isthe onlycomponentofthe OLTC 1 which is directlydriven bythe motor27. P2024,0483 WO N / P230263WO01 May5,2025 -17 -Further, there is a second shaft 22. The second sha ft 22comprises one or a plurality of cam profiles 29. Op tionally,the second shaft 22 runs through the package 4, how ever, thesecond shaft 22 does not provide forward or backwar d movementof the package 4 but may serve as guidance of the p ackage 4.Moreover, the package 4 slides along a first electr iccollector rail 61 to output the electric power from thetransformer10.The fast-moving selector contact package 5 slides a long asecond electric collector rail 62 which may be conf igured asa double railforimproved guidance ofthe package 5.Also,the second electric collector rail 62 is configured for poweroutput. It is possible that both collector rails 61 , 62 areneutrallines.The driving system 2 mayoptionally include an auxiliaryrail23 to also guide the package 5.For reliablepositioning of the package 5 along the auxiliary ra il 23,there can be an interlock 28 that fixes the package 5 atdistinct interlock positions 25 assigned to positio ns of theselectorcontacts11,12,19.The interlock28 may comprise alever interacting with protrusions or holes arrange d at theauxiliaryrail23.In addition, the driving system 2 includes a drivin gmechanism 26, a first force store unit 31 and a sec ond forcestore unit 32. The first force store unit 31 is loc ated atthe fast-moving selector contact package 5, for exa mple. Thesecond force store unit32 islocated atan end of the secondshaft 22 next to the driving mechanism 26, for exam ple.The first force store unit 31 may be or may include a springattached to a first end plate 71 and a second end p late 72between which the fast-moving selector contact pack age 5 is P2024,0483 WO N / P230263WO01 May5,2025 -18 - located.The spring mayrun through the package 5, forexample. When the slow-moving selector contact pack age 4moves from the first selector contact 11 to the sec ondselector contact 12, the first end plate 71 moves t ogetherwith eh slow-moving selector contact package 4 so t hat thefirst force store unit 31, that is, by way of examp le aspring, is loaded, see Figures 6 to 9. When the fir st forcestore unit 31 is released, then the second end plat e 72 ispulled by the first force store unit 31 to the firs t endplate 71 so that the fast-moving selector contact p ackage 5movestowardsthe firstend plate 71.The first force store unit 31 is released, for exam ple, bymeans ofan unlocking arm 24 ofthe driving system 2.Forexample, the unlocking arm 24 interacts with the in terlock28. In other words, the unlocking arm may release t heinterlock 28 from the respective interlock position 25 sothat the fast-moving selector contact package 5 can movefreely. Consequently, the fast-moving selector cont actpackage 5 is pushed by the second end plate 72 to t heposition of the second selector contact 12. The unl ocking arm24 is triggered by the cam profile 29 of the second shaft 22next to the slow-moving selector contact package 4.As the arrangement of the plates 71, 72 and the fir st forcestore unit31 isessentiallysymmetricalalong the secondelectric collector rail 62, movement in the opposit edirection happensanalogously.The driving mechanism 26 of the driving system 2 isconfigured to also load the second force store unit 32 whenthe first shaft 21 is rotated by the motor 27. Henc e, withrotation of the first shaft 21, both force store un its 31, 32 P2024,0483 WO N / P230263WO01 May5,2025 -19 -are charged, the second force store unit 32 by mean s of thedriving mechanism 26 and the first force store unit 31 bymeans of the movement of the slow-moving selector c ontactpackage 4.The second force store unit 32 is released, for exa mple, whenthe slow-moving selector contact package 4 has arri ved at thedesired position, that is, at the adjacent selector contact12. This means, for example, that the first shaft 2 1 has madea specific number of turns. When the specific numbe r of turnsis reached, the second force store unit 32 is relea sed. Uponbeing released, the second shaft 22 starts to rotat e so thatthe unlocking arm 24 can be triggered. Moreover, th e drivingmechanism 26 may comprise a further drive, like a G enevadrive 261. By means of the Geneva drive 261, rotati on of thesecond shaft 22 and / or driving of the electric swit chelements 151, 152 can be controlled. For example, t here areswitch arms262,263 from the driving mechanism 26 to eachone of the switch elements 151, 152 to individuallymechanicallyaddressthe switch elements151,152, see,forexample, Figure 9. The switch elements 151, 152 may only beaddressed between starting and ending the movement ofthefast-moving selector contact package 5 and may othe rwise bekeptin theirpositions. Otherwise,the same asto Figures1 and 2 mayalso applyto Figures3 to 9,and vice versa. In Figure 10,the electricwiring ofthe OLTC 1 isschematically illustrated in a simplified manner. T hat is,the OLTC 1 mayprovide a firstelectricpath and a second electricpath between the electriccollector6 and thewinding 17 to which the selector contacts 11, 12 ar e P2024,0483 WO N / P230263WO01 May5,2025 -20 - assigned.In the firstelectricpath,there isthe first electricswitch element151.Ifthe firstelectric switchelement 151 is closed, that is, in a conductive sta te, thenthe respective selectorcontact11,12 isdirectly connected with the electriccollector6.The second electric pathcomprises the second electric switch element 152 as well asthe resistor package 16 and / or the preventive autot ransformer13.Otherwise, the same as to Figures 1 to 9 may also a pply toFigure 10,and vice versa.In Figure 11, an operating method for the OLTC 1 in thetransformer10 isexplained in more detail.In optional method step S1, the OLTC receives an in structionto switch between two adjacent ones of the differen t windingtaps, that is, between two adjacent ones of the sel ectorcontacts 19, for example, from the first selector c ontact 11to the second selectorcontact12. In method step S2,upon receiving the instruction, the motor27 starts to rotate the first shaft 21. Thus, the s low-movingselector contact package 4 starts moving from the f irstselectorcontact11 to the second selectorcontact 12.Due to thismovement,- the contact clamps 41 are released from a first t erminal114 ofthe firstselectorcontact,- the second force store unit 32 is loaded by means of thedriving mechanism 26,and -the firstforce store unit31 isloaded bymeans ofmovement of the slow-moving selector contact packag e 4. P2024,0483 WO N / P230263WO01 May5,2025 -21 -Method step S2 lasts until the contact clamps 41 ma ke contactwith a first terminal 124 of the second selector co ntact 12.Up to thispoint,the fast-moving selectorcontact package 5remains unaffected and the contact clamp 51 still c lamps on asecond terminal 115 of the first selector contact 1 1. Duringmethod step S2, the first electric switch element 1 51 isclosed and the second electric switch element 152 i s opened,and current flows from the first selector contact 1 1 via thefast-moving selector contact package 5 to the secon d electriccollectorrail62.In method step S3, the slow-moving selector contact package 4gets into contact with the first terminal 124 of th e secondselector contact 12. That is, the slow-moving selec torcontact package 4 reaches it end position or gets c lose toitsend position.‘Close’means,forexample,that a distancebetween the final end position at the second select or contact12 and an actual position of the slow-moving select or contactpackage 4 along the first shaft 21 is at most 90% o r at most50% or at most 30% of a length of the contact clamp s 41 alongthe firstshaft21.Arrival of the slow-moving selector contact package 4 at thefirstterminal124 triggersthe following actions: -the second force store unit32 isreleased,and -the second shaft22 startsto rotate.In method step S4, the effects of method step S3 em erge:-the second electricswitch element152 isclosed bymeansof the Geneva drive 261 and the second switch arm 2 63,- afterwards, the first electric switch element 151 is openedbymeans ofthe firstswitch arm 262,and- the unlocking arm 24 is triggered by the second s haft 22 so P2024,0483 WO N / P230263WO01 May5,2025 -22 - thatthe firstforce store unit31 isreleased and the fast-moving selector contact package 5 starts to move af ter thefirstelectricswitch element151 hasbeen opened.Thus, for a short period of time both electric swit chelements 151, 152 are in a closed state, for exampl e, for atmost 0.1 s or for at most 0.01 s. Subsequently, the firstelectricswitch element151 isopened so thatthen thecontact clamps 51 of the fast-moving selector conta ct package5 can leave the second terminal 115 of the first se lectorcontact11.In method step S6, the contact clamps 51 of the fas t-movingselector contact package 5 arrive at the second ter minal 125of the second selector contact 12. Thus, the fast-m ovingselector contact package 5 reaches its end position or getsclose to its end position. Upon making contact betw een thecontactclamps51 and the second terminal125,- the first electric switch element 151 is closed b y means ofthe driving mechanism 26,- subsequently the second electric switch element 1 52 isopened,and- optionally the fast-moving selector contact packa ge 5interlockswith the auxiliaryrail23.In optional method step S7, finishing the tap chang ing isconfirmed. Hence,uninterrupted switching between tapscan be achieved. Otherwise,the same asto Figures1 to 10 mayalso applyto Figure 11,and vice versa. P2024,0483 WO N / P230263WO01 May5,2025 -23 - In Figure 12,a more detailed representation ofan example ofa transformer 10 is shown. In this example, the tra nsformer10 is for three electric phases and, thus, comprise s three ofthe OLTCs 1 which are assigned in a one-to-one mann er to thephases. The OLTCs 1 are each located at a high-volt age sideof the corresponding selector contacts 11, 12, 19 o f thewinding 17 and connected to the respective collecto r. As analternative to three one-phase OLTCs 1, there can b e onethree-phase OLTC, not shown. The same applies to al l otherexamplesofthe transformer10 and the OLTC 1.For example, the winding 17 comprises three units e ach havinga regulation winding 171 connected with the selecto r contacts11, 12, 19 and a high-voltage winding 172 connected with thesource by means of transformer bushings 173. All th ree unitsof the winding 17 are applied on a same soft iron s tructure174.Further, for example, the OLTCs 1 can be arranged i n alinear, straight manner. An overall length of the t hree OLTCs1 along the winding 17 is,forexample,the length ofthe winding 17 along the same direction ofextend,for example,with a tolerance of at most 40% or at most 15% of s aid lengthof the winding 17. Especially, the overall length o f thethree OLTCs 1 can be smaller than said length of th e winding17 so that a compact, space-saving arrangement is p ossible.Allthree OLTCs1 maybe ofthe same design. Otherwise,the same asto Figures1 to 11 mayalso applyto Figure 12,and vice versa. The componentsshown in the figuresfollow,unless indicatedotherwise, exemplarily in the specified sequence di rectly one P2024,0483 WO N / P230263WO01 May5,2025 -24 -on top of the other. Components which are not in co ntact inthe figures are exemplarily spaced apart from one a nother. Iflines are drawn parallel to one another, the corres pondingsurfaces may be oriented in parallel with one anoth er.Likewise, unless indicated otherwise, the positions of thedrawn components relative to one another are correc tlyreproduced in the figures.The invention described here is not restricted by t hedescription on the basis of the exemplary embodimen ts.Rather, the invention encompasses any new feature a nd alsoany combination of features, which includes in part icular anycombination offeaturesin the patentclaims,even ifthisfeature or this combination itself is not explicitl yspecified in the patent claims or exemplary embodim ents.

[0002] P2024,0483 WO N / P230263WO01 May5,2025 -25 - ListofReference Signs 1 on-load tap changer,OLTC 2 driving system 21 firstshaft 22 second shaft 23 auxiliaryrail 24 unlocking arm 25 interlockposition 26 driving mechanism 261 Geneva drive262 first switch arm to the first electric switch e lement263 second switch arm to the second electric switch element27 motor 28 interlock 29 cam profile 31 firstforce store unit 32 second force store unit 4 slow-moving selectorcontactpackage 41 contactclamp 5 fast-moving selectorcontactpackage 51 contactclamp 6 electriccollector 61 firstelectriccollectorrail 62 second electriccollectorrail 71 firstend plate 72 second end plate 10 transformer,e.g.distribution transformer 11 firstselectorcontact 114 firstterminal 115 second terminal 12 second selectorcontact 124 firstterminal P2024,0483 WO N / P230263WO01 May5,2025 -26 - 125 second terminal 13 preventive autotransformer 14 insulation body 151 firstelectricswitch element 152 second electricswitch element 16 resistorpackage 17 winding 171 regulation winding 172 high-voltage winding 173 transformerbushing 174 softiron structure 18 source 19 furtherselectorcontact method step

Claims

P2024,0483 WO N / P230263WO01 May5,2025 -27 - PatentClaims1. An on-load tap changer (1), OLTC, for a transfor mer (10)comprising:- a driving system (2) including a first force stor e unit(31), -a slow-moving selectorcontactpackage (4),and -a fast-moving selectorcontactpackage (5), wherein -the driving system (2)isconfigured to move the slow-moving selector contact package (4) with a first sp eed andthe fast-moving selector contact package (5) with a secondspeed from a first selector contact (11) of the tra nsformer(10) to a second selector contact (12) of the trans former(10),the second speed isatleasttwice the first speed,- the driving system (2) is further configured to b egin amovement of the fast-moving selector contact packag e (5) tothe second selector contact (12) later than a corre spondingmovement of the slow-moving selector contact packag e (4), and-the firstforce store unit(31)isloaded during themovement of the slow-moving selector contact packag e (4) andis subsequently unloaded to drive the movement of t he fast-moving selectorcontactpackage (5). 2.The OLTC (1)according to the preceding claim, wherein the driving system (2)furthercomprisesa firstshaft (21) coupled to and driving the slow-moving s electorcontact package (4), and a second shaft (22) also c oupled tothe slow-moving selectorcontactpackage (4),wherein the second shaft (22) includes a cam profil e (29)triggering movement of the fast-moving selector con tactpackage (5).P2024,0483 WO N / P230263WO01 May5,2025 -28 - 3.The OLTC (1)according to the preceding claim,wherein the slow-moving selector contact package (4 )comprises an unlocking arm (24) coupled to the seco nd shaft(22),wherein the unlocking arm (24) is configured to unl ock thefirstforce store unit(31)afterbeing charged by themovement of the slow-moving selector contact packag e (4) dueto rotation ofthe firstshaft(21).

4. The OLTC (1) according to any one of the two pre cedingclaims, wherein the driving system (2)furthercomprisesa motor(27) and a second force store unit(32),wherein the motor (27) is configured to directly dr ive thefirst shaft (21) and to load the second force store unit (32)during movement of the slow-moving selector contact package(4),wherein the second force store unit (32) is unloade d uponarrival of the slow-moving selector contact package (4) atthe second selector contact (12) to drive the secon d shaft(22).

5. The OLTC (1) according to the two preceding clai ms,wherein rotation ofthe second shaft(22)releases the unlocking arm (24).

6. The OLTC (1) according to any one of the precedi ng claims,furthercomprising a firstelectriccollectorrail (61)and a second electriccollectorrail(62),wherein the slow-moving selector contact package (4 ) isguided along the first electric collector rail (61) and thefast-moving selectorcontactpackage (5)isguided along the second electriccollectorrail(62),P2024,0483 WO N / P230263WO01 May5,2025 -29 -wherein the first force store unit (31) is mechanic allycoupled to the fast-moving selector contact package (5).

7. The OLTC (1) according to any one of the precedi ng claims,wherein trajectories of the slow-moving selector co ntactpackage (4) and of the fast-moving selector contact package(5)run collinearly.

8. The OLTC (1) according to any one of the precedi ng claims,wherein the driving system (2) is configured to sta rt themovement of the fast-moving selector contact packag e (5) uponarrival of the slow-moving selector contact package (4) atthe second selectorcontact(12).

9. The OLTC (1) according to any one of the precedi ng claims,wherein the driving system (2) further comprises an auxiliaryrail(23),wherein the fast-moving selector contact package (5 ) and theauxiliary rail (23) are provided with a mutual mech anicalinterlock(28),wherein at the auxiliary rail (23) there are distin ctinterlock positions (25) associated in a one-to-one mannerwith positions of the first selector contact (11) a nd thesecond selector contact (12), along the auxiliary r ail (23).

10. The OLTC (1) according to any one of the preced ingclaims,wherein the fast-moving selector contact package (5 ) and theslow-moving selector contact package (4) each compr ise acontact clamp (41, 51) configured to electrically c ontact thefirst selector contact (11) and the second selector contact(12) at respective static positions of the fast-mov ingP2024,0483 WO N / P230263WO01 May5,2025 -30 -selector contact package (5) and the slow-moving se lectorcontactpackage (4). 11.A transformer(10)comprising:- an OLTC (1) according to any one of the preceding claims,and- a first selector contact (11) and a second select or contact(12) being electrically connected with a winding (1 7) of thetransformer(10),wherein the first selector contact (11) and a secon d selectorcontact (12) are assigned in a one-to-one manner to differentwinding tapsofthe winding (17).

12. The transformer (10) according to the preceding claim,wherein the first selector contact (11) and the sec ondselector contact (12) each comprise a first termina l (114,124) and a second terminal (115, 125) at a same ele ctricpotential,wherein the first terminals (114, 124) are electric allycontacted by means of the slow-moving selector cont actpackage (4) and the second terminals (115, 125) areelectricallycontacted bymeansofthe fast-moving selector contactpackage (5).

13. The transformer (10) according to any one of th e twopreceding claims, furthercomprising a firstelectricswitch element (151)and a second electricswitch element(152),further comprising a resistor package (16) and a pr eventiveautotransformer(13),wherein the resistor package (16) and the preventiv eautotransformer (13) are assigned to the second ele ctricswitch element(152),P2024,0483 WO N / P230263WO01 May5,2025 -31 - wherein the firstelectricswitch element(151)is directly assigned to the winding (17),andwherein the second electric switch element (152) isconfigured to be closed during movement of the fast -movingselectorcontactpackage (5).

14. The transformer (10) according to the preceding claim,wherein the firstelectricswitch element(151)is configuredto be opened only when the second electric switch e lement(152)isclosed.

15. An operating method for a transformer (10) acco rding toany one of claims 11 to 14, comprising the followin g steps:- receiving an instruction to switch between the di fferentwinding taps,- upon receiving the instruction, disconnecting the slow-moving selectorcontactpackage (4)from the first selectorcontact (11) and moving the slow-moving selector co ntactpackage (4) to the second selector contact (12), an d chargingthe firstforce store unit(31), -upon arrivalofthe slow-moving selectorcontact package(4) at the second selector contact (12), contacting the slow-moving selector contact package (4) with the second selectorcontact (12) and unloading the first force store un it (31) sothat the fast-moving selector contact package (5) i sdisconnected from the first selector contact (11) a nd so thatmovement of the fast-moving selector contact packag e (5) isinitiated,and -upon arrivalofthe fast-moving selectorcontact package(5) at the second selector contact (12), contacting the fast-moving selector contact package (5) with the second selectorcontact(12).

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