WO2011157318A1

WO2011157318A1 - Tap changer

Info

Publication number: WO2011157318A1
Application number: PCT/EP2011/002123
Authority: WO
Inventors: Wolfgang Albrecht
Original assignee: Maschinenfabrik Reinhausen Gmbh
Priority date: 2010-06-18
Filing date: 2011-04-28
Publication date: 2011-12-22
Also published as: DE102010024326A1; CN202855568U

Abstract

The invention relates to a tap changer (10) for switching among at least two winding taps (12, 14) of a step transformer (16) without interruption, comprising at least one mechanical switching element (MTF, TTF, 32) and at least one vacuum cell (MSV, TTV), which can be jointly switched in different switching directions at a defined time offset from each other. At least one of the mechanical switching elements (TTF) is coupled to a switching shaft (22) by means of a gear train element (34) and has a switching or triggering point in time that is advanced relative to the other switching elements (MTF) or vacuum switching tubes (MSV, TTV) and that is independent of the switching direction.

Description

S t u fe s c h a te rs

The present invention relates to a tap changer for uninterrupted switching between at least two winding taps of a tapped transformer with the features of the independent claim.

From DE 20 21 575 a tap changer is known, the total of four

Having vacuum interrupters per phase. In each of the two existing load branches are each a vacuum interrupter as the main contact and each one more

Vacuum interrupter, in series with a switching resistance, as

Resistance contact provided.

In an uninterrupted load switching from the previous

Winding tap n on a new, preselected winding tap n + 1, the main contact of the turn-off side is first opened, after which the resistance contact of the receiving side is closed, so that flows between the two stages n and n + 1 a limited by the switching resistors compensation current. After the previously closed resistive contact of the disconnecting side has opened, the main contact of the receiving side closes, so that the entire load current from the new winding tap n + 1 leads to the load discharge, whereby the switching is completed.

The vacuum interrupters used in this known tap-changer and numerous similar known embodiments, which are used instead of conventional mechanical contacts for load switching, have a number of advantages. Since the contacts themselves are encapsulated in a vacuum, high levels can be achieved

Realize switching capacities. The encapsulated, hermetically sealed contacts also can not lead to the fouling and contamination of the surrounding insulating oil in the tap-changer by contact erosion or arcing. Furthermore are

Vacuum interrupters are now available as very compact components; they have a small footprint and require only relatively low actuation forces.

In various applications of such known tap changer with

However, vacuum interrupters for regulating power transformers is a high surge voltage resistance of preferably up to voltages of 100 kV and more clearly beyond that required. Such unwanted surge voltages, the amount of which is essentially due to the structure of the tapped transformer and the winding parts between the individual tapping stages, are, on the one hand, lightning impulse voltages that are caused by the

Impact of lightning in the network revealed. For another, too

Switching impulse voltages occur, which are caused by unpredictable switching shocks in the regulated network. If the impulse withstand voltage of the on-load tap-changer is insufficient, short-term step short circuit or undesirable breakdown of the ceramic or vapor shield of affected vacuum interrupters may occur in the load branch not leading to the load current, which may not only cause their long-term damage, but is generally undesirable.

From DE 23 57 209 A and DE 26 04 344 A it is already known, for

Combat too high surge voltages between the load branches

Provide protective spark gaps or voltage-dependent resistors or both; However, these agents are inadequate in various cases and can not or completely exclude harmful impulse stresses in their effect.

An object of the present invention is to propose a tap-changer of the type mentioned, which makes it possible to solve individual of several switching steps from the time very closely staggered sequence of other switching elements of the tap changer, to allow to drain the remaining switching steps with more time margin can.

This object of the invention is with the subject matter of the independent

Patent claim achieved. Features of advantageous developments of the invention will become apparent from the dependent claims. To achieve the object of the invention is a tap changer for uninterrupted switching between at least two

Winding taps of a tapped transformer with the features of independent claim 1 proposed. In this tap changer, at least one mechanical switching element and at least one vacuum interrupter is provided, which are mutually switchable with a defined time offset to each other in different switching directions. At least one of the mechanical switching elements is over

Gear element coupled to a shift shaft and has a relation to the other switching elements or vacuum interrupters and independent of the switching direction timed forward switching or trip time on. This mentioned, a forward switching time having mechanical switching element may preferably be connected in series with at least one other switching element or a vacuum interrupter, which have an open contact at the switching time. This arrangement of the transmission element in the tap changer according to the invention makes it possible in an advantageous manner, a defined switching step or one of several

Separate contact actuations of the remaining switching steps and remove this shift step during the elevator operation of the tap changer from the actually much faster switching the tap changer package and vorververlagern. Thus, already at the slow mounting of the energy storage by clamping the

Energy storage spring or at the selector operation, a switching step of at least one switching element executed, while the remaining switching steps or contact operations are performed only then in rapid succession.

The particular technical advantage of a so-configured tap changer is that it allows the preferably used planetary gear, single "uncritical", ie in the respective switching time not energized switching steps from the temporally very closely staggered sequence of the other switching elements of the tap changer herausverlosen and switched to shift in advance In this way, more time is left over for the remaining switching steps The time advantage achieved allows coarser tolerances since fewer individual switching steps must take place in the entire, non-variable time window of a single switching sequence.

An embodiment of the tap changer according to the invention is

characterized by a coupled between the switching shaft and with this

Actuators and the mechanical switching elements arranged

Gear element for phase shift of the switching time depending on the direction of rotation of the switching shaft. This transmission element may in particular be formed by a planetary stage with which the forward displacement of the desired switching step can be realized in a relatively simple and compact manner.

Furthermore, a rotatable switching shaft is provided, the actuating elements for each actuation phase for the mechanical switching elements or vacuum interrupters are assigned, wherein the actuating elements are each assigned to the switching shaft rotatable, concentric cams with frontal contours. These End-side contours can be formed in particular by projections, cams o. The like., Which are suitable for actuating the switching elements and / or vacuum interrupters. In addition, those of the at least one to be switched with the temporally shifted to

mechanical switching element corresponding cam triggered

Switching times regardless of their direction of rotation or the direction of rotation of the

Shift shaft relative to the rotational movements of the other cams or the other actuators temporally moved forward.

Furthermore, an additional permanent main contact may be provided on the tap changer and / or coupled thereto. In such a tap changer, in each case a mechanical contact (MC), which leads to a continuous current, can additionally be present on the disconnecting and / or connecting side. The contact of such a permanent main contact switch preferably opens on the disconnecting side in front of the switching element MSV, while the contact on the aufschaltenden side after the switching element MSV closes.

The switching or triggering of the at least one mechanical switching element, which is displaced in each switching direction, is implemented in the step switch according to the invention by virtue of the fact that the at least one switching means and its associated one

Cam a transmission element for phase shift of the switching time is assigned depending on the direction of rotation of the shift shaft. This transmission element is by a

Planet stage formed, which is located between the shift shaft and concentric with this arranged cam. The cam can be connected to a ring gear or formed as such, which has an internal toothing, which is in meshing engagement with a plurality of planet gears, which in turn in a

Gearing engagement with a central sun gear, which is rotatably connected to the shift shaft or mounted on this. During a rotational movement of the switching shaft an accelerated or defined temporally shifted rotational movement of the correspondingly coupled cam is triggered by means of the translation stage of the planetary gear, regardless of the selected switching direction.

The invention will be described below with reference to embodiments

Use of the drawings described below explained in more detail. Fig. 1 shows a schematic perspective view of an embodiment of a tap changer according to the invention, comprising a switching shaft with arranged thereon actuating elements and switching elements coupled thereto. 2 shows a flowchart to illustrate the switching sequences of a variant of the tap changer during a switching cycle in respectively different ones

Switching directions.

Fig. 3 shows in several circuit diagrams, the individual, successive

Switching states of the various components of the tap changer in a first

Switching direction.

Fig. 4 shows in several circuit diagrams, the individual, successive

Switching states of the various components of the tap changer in a second switching direction. FIG. 5 shows, by means of a further circuit diagram, a variant of a tap changer supplemented by two additional permanent main contacts.

The embodiment described below is not intended to be limiting, but serves to explain the function and the switching options of a tap changer according to the invention. The schematic perspective view of Fig. 1 shows an embodiment of a tap changer 10 according to the invention, comprising a switching shaft 22 with arranged thereon actuating elements 24 and coupled therewith switching elements 26. As will be explained in more detail with reference to Figures 2 to 5 with reference to further embodiments, has a vorverlagerter Switching or trip time of one of several mechanical switching elements (here: the second mechanical switching element TTF) a defined time interval to the other switching or tripping times of other mechanical switching elements and / or vacuum interrupters (here: the first

mechanical switching element MTF and the two vacuum interrupters MSV and TTV) on. In addition, the temporally shifted switching or triggering time having mechanical switching element TTF switches in time before all other switching elements and

Vacuum switching tubes, regardless of the switching direction, i. from the direction of rotation of the switching shaft 22nd

The embodiment variant of the invention shown in FIG

Tap changer 10 provides a switching shaft 22 rotatable about its axis in both directions, the four parallel, disc-shaped actuators 24 for each

Actuation phase for the mechanical switching elements 26 and vacuum interrupters are assigned, wherein the actuating elements 24 each by rotatable by the switching shaft 22, concentric cams 28 with peripheral contours or

Projections 30 are formed. Optionally, such contours and / or projections could also be arranged on the front side of the cams. These projections 30 solve the respective switching elements 26 and vacuum interrupters via not shown here

Cams off.

As can be further seen in FIG. 1, each of the four existing cams 28 may each have a plurality of evenly spaced projections 30 on its outer circumference so that complete rotation of the control shaft 22 by 360 degrees is not required for a complete shift cycle of the tap changer 10 is, but that, for example, already a 120 ° rotation can be sufficient for this. In addition, the outer contours of the projections or cams 30 of the cam disks 28 and a gear element 34 arranged between the selector shaft 22 and the lowermost cam disk 28 enable the switching points 28 triggered by the at least one cam plate 28 corresponding to the temporally shifted mechanical switching element TTF to be shifted independently From its direction of rotation or from the direction of rotation of the switching shaft 22 relative to the rotational movements of the other cams 28 and the other actuators 24 are temporally forward displaced.

The switching or triggering of the second mechanical switching element TTF (FIGS. 3 and 4), which is designated by the reference numeral 32 in each switching direction, is realized in the illustrated tap changer 10 in that the respective switching means or actuating element 24 and associated with this

Cam 28 is a transmission element 34 associated with the phase shift of the switching time depending on the direction of rotation of the switching shaft 22. This transmission element 34 is designed as a compact, flat-mounted planetary gear 36, the sun gear 38 is rotatably connected to the shift shaft 22. The sun gear 38 is located in

Gearing engagement with three small planetary gears 40, which in turn

Gear engagement with a ring gear 42 with internal teeth 44 are rotatably associated with the corresponding to the second mechanical switching element TTF

Cam 28 is connected. These cooperating gear elements define by their translations and arrangements the switching times of the switching element TTF, ie, the shift shift, which has in each direction of rotation of the shift shaft 22 is an exactly equal time interval to the shift start. Thus, by the in Fig. 1 Stepped switch with planetary gear shown exemplarily illustrates the general idea of the invention, by each forward shifting of the mechanical

Switching element TTF or 32 one of several load branches independent of the respective switching direction of the switching shaft 22 to ensure a desired surge voltage resistance or aO-strength. In this way, any occurring burden

Surge voltages the vacuum interrupters in each case not the load current leading

Last branch not and thus remain harmless for the vacuum interrupters.

The representation of FIG. 2 is a flowchart of the switching sequences of an embodiment of a tap changer according to the invention with planetary gear, in particular according to FIG. 1, during a switching cycle in each case different

Clarify switching directions. The upper diagram illustrates the switching sequence of a total of four individual switching units tap changer in a first

Switching direction, characterized by a drive direction in the diagram from left to right, while the lower diagram shows the switching sequence in opposite switching direction, characterized by a drive direction in the diagram from right to left.

With the planetary stage 36 of the gear element 34 shown in FIG. 1, it is possible for the step switch 10 to be switched from the actual fast during the elevator pull operation

Switchover of all switching steps a single switching step be removed and moved forward. Here this is the contact operation of the mechanical switching element TTF. Thus, already at the slow mounting of the energy storage by clamping the

Energy storage spring or the Vählerbetätigung a switching step of the switching element TTF are performed while the other switching elements MTF and vacuum interrupters TTV and MSV are switched later or operated in close time sequence. The used planetary gear 36 makes it possible in an advantageous manner, individual as uncritically classified switching steps that are not energized in the respective switching time to dissolve out of the temporally very closely staggered sequence of other switching elements of the tap changer 10 and to shift it in advance. In this way remains for the remaining switching steps more latitude, which coarser tolerances are possible, both as regards the mechanical design of the tap changer 10 as well as its switching sequences. This results in an additional time advantage, since fewer individual switching steps in the entire, otherwise unchangeable time window of a single switching sequence (see FIG. The schematic representations of FIG. 3 (FIGS. 3 a to 3 g) show, in a total of seven circuit diagrams, the individual, successive switching states of

various components of the FIG. 1 equipped with the planetary gear tap changer in a first switching direction, which is characterized in Fig. 3a by the switching direction n n + 1.

The tap changer 10 illustrated in FIG. 3 on the basis of a circuit diagram serves for the uninterrupted switching between two winding taps 12 and 14 of a tapped transformer 16. The tap changer 10 forms a load branch with two parallel paths 18 and 20. Each of these paths 18 and 20 comprises a series arrangement a vacuum interrupter MSV, TTV and a mechanical switching element MTF, TTF, in the present context as a variably adjustable or switchable

Switching contact can be designated. The first path 18 is formed by the series-connected first vacuum interrupter MSV and the first mechanical switching element MTF. The second path 20 is formed by a series connection of the second vacuum interrupter TTV, the second mechanical switching element TTF and a resistor R. By

Switching the two mechanical switching elements MTF and TTF and by opening and closing the two vacuum interrupters, the two winding taps 12 and 14 of the tapped transformer 16 can be variably coupled to each other and / or acted upon with a load dissipation LA. The two vacuum interrupters MSV and TTV and the two mechanical

Switching elements MTF and TTF are shown in FIG. 2 with a defined time offset to each other in each case different switching directions (n -> n + 1 or n + 1 - n) together switchable. As can be seen with reference to FIG. 2, the second mechanical

Switching element TTF a relation to the first switching element MTF and the two vacuum interrupters MSV and TTV and independent of the switching direction temporally advanced switching or tripping time on. The second mechanical switching element TTF thus switches independently of the selected switching direction before all others

Switching elements MTF or vacuum interrupters MSV and TTV, whereby certain

Switching states can be realized in a simple, reliable and exactly reproducible manner by means of mechanical means. As can be clearly seen in FIG. 2, the second mechanical switching element TTF, which has a temporally shifted switching or triggering time, switches in front of all other switching elements and vacuum tubes. The diagram of Fig. 2 shows the processes in a complete switching operation, starting from the time zero, above for a drive direction from left to right (n -> n +), ie ending at a definable time (see Fig. 3) and below for a

Drive direction from right to left (n + 1 - n), i. starting at a definable time corresponding to the lower scale and ending at the far left at zero. The switching position of the tap changer 10 for the start of switching is illustrated in Fig. 3a. The first

Vacuum interrupter MSV is closed while the switching contact of the second vacuum interrupter TTV is open. The first mechanical switching element MTF is in a first switching position, in which the load current I _L from the first

Winding tap 12 of the tapped transformer 16 via the first mechanical

Switching element MTF and the closed first vacuum interrupter MSV can flow to the load discharge LA. According to the circuit diagram of Fig. 2, the second mechanical switching element TTF is switched very early, which is already indicated in Fig. 3a by the switching arrow. In the position still switched in FIG. 3a, the second mechanical switching element TTF forms a connection from the first winding tapping 12 to the second vacuum interrupter TTV, whose switching contact is still open at this time, so that no additional or parallel current can flow to the load lead LA via this ,

After the second mechanical switching element TTF on the second

Winding tap is switched 14 (see Fig., 3b), after a short time, a closing of the switching contact of the second vacuum interrupter TTV, so that flows in yet closed first vacuum switch tube MSV a loop current l _c in the right loop, as in Fig. 3c by the ring arrow is indicated around the load lead LA. Shortly thereafter, the first vacuum interrupter MSV is opened (see Fig. 3c). This open switching position in a relatively short time after the start of switching is illustrated in Fig. 3d. In this

Switching state of the tap changer 10 with the open first vacuum interrupter MSV and the closed second vacuum interrupter TTV and in the first switching position of the second mechanical switching element TTF shown in Figures 3b to 3g of Laststom l _{L flows} in the manner shown in Figures 3d and 3e of the first

Winding tapping 12 of the tapped transformer 16 through the second load branch or second path 20, which can also be referred to as a resistance branch or R-branch, for load derivation LA. After another short time, the first mechanical

Switching element MTF switched (Fig. 3d, Fig. 3e), whereby the closing of the first

Vacuum switch tube MSV (Fig. 3e, Fig. 3f) and the subsequent opening of the second vacuum interrupter TTV (Fig. 3f, Fig. 3g) is prepared. The load current I _L flows in the manner shown in Fig. 3g of the second winding tapping 14 of the

Stepped transformer 16 through the appropriately switched first mechanical

Switching element MTF and the closed first vacuum interrupter MSV for load dissipation LA. It should be noted that in this switching cycle shown, the second mechanical switching element TTF at the end of the circuit no longer on the first

Winding tap 12 is switched, but remains in the switching position selected switching position.

On the basis of the illustration of the individual switching operations of the switching cycle illustrated in Fig. 3 (n n + 1, Fig. 2 above) it is clear that the second mechanical

Switching element TTF first switched in the aforementioned manner and then no longer switched back in the course of the switching cycle. Since this should also be the case in the opposite direction of switching according to the present invention, suitable

Provide arrangements to turn the second mechanical switching element TTF turn in turn otherwise switching in reverse order other components MTF, MSV and TTV first. This can be ensured according to the present invention, in particular by means of the explained in more detail with reference to FIG. 1 gear member.

The representations of FIG. 4 show in several circuit diagrams the individual, successive switching states of the various components of the tap changer in a second switching direction. Thus, the lower diagram of FIG. 2 shows the operations in a complete downshift, for a right-to-left drive direction (n + 1 -> n), i. starting at a time corresponding to the lower scale in the right area and ending at the very left at zero. The switching position of the tap changer 10 at the start of switching within a first period is illustrated in FIG. 4a. The first

Vacuum interrupter MSV is closed while the switching contact of the second vacuum interrupter TTV is open. The first mechanical switching element MTF is in its second switching position, in which the load current I _L from the second

Winding tap 14 of the tapped transformer 16 via the first mechanical

Switching element MTF and the closed first vacuum interrupter MSV can flow to the load discharge LA. This is at the same time the switching position corresponding to Fig. 3g, with which the first switching cycle has been completed according to the upper diagram of FIG.

The illustrated embodiment of the invention provides in this case that the second mechanical switching element TTF is already switched at a very early time, which is indicated by the curved switching arrow in the area of the switch TTF. The priority switching of the second mechanical switching element TTF takes place according to the present invention in both switching directions, which is to be realized in the downshift according to FIG. 4, in particular, that the switching movement of the second mechanical switching element TTF at least partially decoupled from the switching movements of the other switching elements or vacuum interrupters is, in particular by means of the transmission element corresponding to FIG. 1.

After the early switching of the second mechanical switching element TTF, the second vacuum interrupter TTV is closed after a definable time (Fig. 4b, Fig. 4c), after which the first vacuum interrupter MSV is opened (see Fig. 4c and Fig. 4d). This opening of the first vacuum interrupter MSV takes place within a definable period of time after the start of the shift, which is illustrated in FIG. 4c (open) and in FIG. 4d (open MSV). In this switching state of the tap changer 10 with the opened first vacuum interrupter MSV and the closed second vacuum interrupter TTV and in the second switching position of the second mechanical switching element TTF shown in Figures 4b to 4g of the load current flows _{L L} in the manner shown in Figures 4c and 4d from the first winding tapping 12 of the tapped transformer 16 through the second load branch or second path 20, which can also be referred to as a resistance branch or R branch, to the load lead LA (cf., for example, FIG. 4d). Previously, the Laststom l _L flowing in the through 4c in Figures 4a manner shown by the second winding tap 14 of the tapped transformer 16 through the first load branch and the first path 18 to the load shunt LA (see. For example. Fig. 4 or Fig. 4b).

After a further short period of time, the first mechanical switching element MTF is switched over (FIGS. 4d, 4e), whereby the closing of the first vacuum interrupter MSV (FIGS. 4e, 4f) and the subsequent opening of the second

Vacuum stop tube TTV (Fig. 4f, Fig. 4g) is prepared. The load current I _L thus flows again in the manner shown in Fig. 4g from the first winding tap 12 of the tapped transformer 16 through the correspondingly connected first mechanical

Switching element MTF and the closed first vacuum interrupter MSV for load dissipation LA, whereby the switching cycle is completed. In this way, it is again clear from the illustration of the individual switching operations of the switching cycle (n + 1 -n, FIG. 2, bottom) shown in FIG. 4 that the second mechanical switching element TTF is first switched in the manner mentioned. The illustrated switching times of the second mechanical switching element TTF form an implementation of the general idea of the invention, by respectively shifting the mechanical switching element TTF in one of two load branches

regardless of the switching direction to achieve the desired surge voltage resistance or aO strength can. In this way, any occurring burden

Surge voltages the vacuum interrupters MSV and TTV in each case not the load current leading load branch and thus remain harmless for the vacuum interrupters.

The illustration of FIG. 5 shows, with reference to a further circuit diagram, a variant of a tap changer 10 supplemented by two additional switches or permanent main contacts MC (MC1 and MC2). In this alternative or optionally supplemenable variant of FIG

Stepping switch 10 are additionally on the off and aufschaltenden side each mechanical contacts MC, i. MC1 or MC2, provided. These so-called permanent main contacts MC or additional switches each carry a continuous current. The contact of such

Permanent main contact switch preferably opens on the disconnecting side in front of the switching element MSV, while the contact on the aufschaltenden side after the

Switching element MSV closes.

Claims

Tap changer (10) for uninterrupted switching between at least two winding taps (12, 14) of a tapped transformer (16), with at least one mechanical switching element (MTF, TTF, 32) and at least one

Vacuum cell (MSV, TTV), which are mutually switchable with a defined time offset to each other in different switching directions, and wherein at least one of the mechanical switching elements (TTF) via a transmission element (34) with a switching shaft (22) is coupled and one with respect to the rest

Switching elements (MTF) or vacuum interrupters (MSV, TTV) and of the

Has switching independent independent time shifted switching or trip time.

Tap changer according to Claim 1, in which the mechanical switching element (TTF) having a pre-shifted switching time is connected in series with at least one further switching element or a vacuum cell (TTV), which is connected to

Switching point have an open contact.

Tap changer according to Claim 1 or 2, characterized by a gear element (34) arranged between the selector shaft (22) and actuating elements (24) coupled thereto and the mechanical switching elements (MTF, TTF, 32) for phase shifting the switching time depending on the direction of rotation of the selector shaft ( 22).

4. tap changer according to one of claims 1 to 3, wherein the vorverlagerte Schaltbzw. Tripping time a defined time interval to the remaining Schaltbzw. Release times of the other mechanical switching elements (MTF) and vacuum interrupters (MSV, TTV) has. 5. Tap changer according to one of claims 1 to 4, wherein the one temporally

vorverlagerten switching or tripping time point having mechanical

Switching element (TTF) upstream of all other switching elements (MTF) and vacuum interrupters (MSV, TTV) upstream.

6. Tap changer according to one of claims 1 to 4, wherein the one temporally

vorverlagerten switching or tripping time point having mechanical Switching element (TTF) switches all other switching elements (MTF) and vacuum interrupters (MSV, TTV) downstream.

7. tap changer according to one of claims 1 to 6, comprising a rotatable switching shaft (22), the actuating elements (24) for each actuation phase for the

Mechanical switching elements (MTF, TTF) or vacuum interrupters (MSV, TTV) are assigned, wherein the actuating elements (24) each of the switching shaft (22) rotatable, concentric cams (28) with frontal or

circumferentially contours, projections, cams (30) o. The like. Are assigned, and wherein the at least one cam (28) triggered switching times regardless of the direction of rotation of the switching shaft (22) relative to the

Rotary movements of the other cams (28) or the rest

Actuators (24) are temporally forward or relocated.

8. tap changer according to claim 7, wherein the transmission element (34) for

Phase shift of the switching time depending on the direction of rotation of the switching shaft (22) is associated with the at least one switching means or actuator (24) and associated therewith the cam (28).

9. Tap changer according to claim 8, wherein the transmission element (34) comprises at least one planetary stage (36) which is arranged between the switching shaft (22) and the cam disc (28) arranged concentrically therewith.

10. tap changer according to claim 9, wherein a sun gear (38) of the planetary stage (36) with the switching shaft (22) is rotatably connected, and in which, via planet gears (40) with the sun gear (38) in meshing ring gear ( 42) with internal toothing (44) with the second mechanical switching element (TTF) associated cam (28) is rotatably connected.

11. Tap changer according to one of Claims 1 to 10, in which a mechanical contact (MC), which leads to a continuous current, of which the contact preferably opens on the disconnecting side in front of the switching element MSV, respectively, is present on the disconnecting and switching side. on the upstream side after the switching element MSV closes.