HK1189421B - On-load tap changer - Google Patents

Description

The invention relates to a load step switch with a separate switch and a load switch for uninterrupted switching between different winding sockets of a step transformer under load. The step switches of the type mentioned at the beginning have a separate switch for powerless pre-selection of the winding socket to be switched to and a load switch for actual switching from the previous to the new winding socket. Since this switching is done in a streamlined manner, the load step switches have a power storage.

The power storage for a load switch is already known from DE-PS 19 56 369 and DE-PS 28 06 282. It is pulled by the load switch's drive shaft at the beginning of each operation, i.e. tense. The known power storage consists essentially of a lift slide and a jump slide, between which power storage is arranged as energy storage.

The lift slide is moved linearly relative to the spring by an eccentric connected to the drive shaft; this causes the force storage foam between them to be tense. When the lift slide reaches its new end position, a stop of the spring is released. This is then followed by a jump, as standing under the force of the force storage springs, the previous linear movement of the lift slide is also linearly replicated.

WO89/08924 also contains a spring spring drive, whose spring is capable of being pulled by a drive, the drive element being connected to a special clutch element which can be actuated in one direction only, regardless of the direction of rotation of the drive.

WO2006/00452 A1 concerns another such arrangement in which a special mechanical gear is used to operate the permanent main contacts of a load switch in the same direction regardless of the direction of actuation of the drive shaft.

A very similar arrangement is known from WO2007/067144 A1, which describes a device for transmitting a rotational motion in a load switch by converting the rotational motion of a drive shaft rotating in both directions into the rotational motion of a drive shaft rotating in the same direction.

DE 2 339 973 A1 reveals a load switch with free-running load selector and two malt cycle mechanisms. A spring as a power storage device operates exclusively on a first malt cycle. Another malt cycle acts on the activation of a load switch with US 3,572,143 A and GB 798 740 A.

The power storage systems known from the state of the art for a load switcher of the type mentioned at the outset therefore allow either a back-and-forth switch in successive circuits or a forward switch always in the same direction.

The purpose of the invention is to specify a step switch of the type described at the beginning with a force storage device which allows several switches in one direction and alternately a reverse switch, depending on the direction of rotation of the drive shaft. The force storage device according to the invention is designed to be simple, to be capable of avoiding the use of complex mechanical means for the reversal of motion and to be operated directly by means of any direction of rotation of the drive shaft, even in several consecutive circuits.

Although a force storage device which can be directly tensioned by a drive shaft rotating in any direction and which follows the action of this rotation is already known from WO2007/095978 A1, this known force storage device is only suitable for a load switcher of the type of the load switch, in which the pre-selection of the winding socket and the actual load switching are structurally combined. It is not suitable for a load switcher of the type mentioned at the beginning with a separate switch and load switch. This is particularly so because the known force storage device has a fixed angle corresponding to the distance between the adjacent - in each case charged - oil contact loads according to the

The invention is solved by a load switcher with a power storage device as described in claim 1. The sub-claims concern particularly advantageous further training of the invention.

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The invention is explained in more detail below by means of illustrative drawings showing: Figure 1a load switch according to the invention, more precisely its drive without the load switch contacts and switches in a schematically shown rest positionFigure 2a load switch after the start of operationFigure 3a load switch when the power storage device is in continuous operation, i.e. lifting the power storage deviceFigure 4a load switch when the power storage device is fully charged at the time of its activationFigure 5a load switch after the power storage device is activated and thus the configuration of the undisplayed load switch contactsFigure 6a load switch in a schematically displayed rest positionFigure 7a load switch when the power storage device is in continuous operation, i.e. lifting the power storage deviceFigure 4a load switch when the power storage device is fully charged at the time of its activationFigure 5a load switch after the power storage device is activated and thus the configuration of the load switch contactsFigure 6a load switch in a schematically displayed rest positionFigure 7a load switch after the activation of the power storage deviceFigure 7a load switch in a complete configurationFigure 8a load switch in the direction of the load after the activation of the load storage device has been fully charged and the load is in a full load mode of n+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1+1

The drive shaft 1 is operated by a drive not shown here. On the drive shaft 1 is a gear 2 which interacts with another gear 3 whose storage is not shown. On the gear 3 is a socket 4. This socket 4 corresponds to a further socket 5a which is located on an intermediate shaft 6 which is centrally located within the gear 3 and independent of this rotary. On the socket 5a is a bolt 5 which is rearranged and connected to a 7th gear of a 8th gear; a force 9 is operated by it.In the lower part of the intermediate shaft 6 there is a further actuator 10 corresponding to a counter-actuator 11 on a drive wheel 12. The drive wheel 12 is again rotatable independently of the components mentioned above. It has a roller 13 which interacts with a malting wheel 14, i.e. can intervene in it. The malting wheel 14 is in turn connected to a load switching drive 15 only indicated, which in turn operates the load switching switch 18 not shown here (see Figures 6 to 8).

The load-level switch according to the invention thus has two separate free runs: a first free run consisting of stroke 4 and corresponding stroke 5a and a second free run consisting of stroke 10 and counter stroke 11.

Figure 1 shows this load switch at the start of operation. The drive shaft 1 starts to rotate so that the gear 2 and the gear 3 also rotate.

Figure 2 shows this load step switch with continuous rotation of the drive shaft 1. Now the beam 4 meets the beam 5a of the intermediate shaft 6, rotates it and simultaneously pulls on the force storage shaft 8, or more precisely its force storage spring 9.

Figure 3 shows the load level switch according to the invention as the power storage unit 8 is further lifted. The impact 10 now hits the counter impact 11 and the drive wheel 12 begins to rotate.

Figure 4 shows the position at full lift of the power storage 8. The bolts 5 and thus the actuating rod 7 of the power storage 8 have reached the dead point on the gear 3 and, at continued rotation, the power storage spring 9 is relaxed in a spring-like manner.

Figure 5 shows how the power supply 8 turns the drive wheel 12 rapidly as a result of the disconnected power supply 9 breaking. By turning the drive wheel 12 the roller 13 reaches the power supply 14 and turns it. This also turns the load switch drive 15 which in turn jumps the power supply 18 i.e. its contacts. At the same time the drive shaft 1 still turns at a certain angle. If for any reason, due to a break in the power supply spring 9, the power supply 8 does not turn off and the power supply 14 cannot be operated from the unbalanced power supply 8 as originally intended, the new power supply position of the power supply switch 18 is reached. This is achieved by continuously increasing the load load load.

Figure 6 shows the schematic overall structure of a load-level switch according to the invention. It is shown that a first free-run 16 is provided between gear 3 and power storage 8 and that this free-run 16 consists of the connecting switch 4 and the corresponding switch 5a shown in Figures 1 to 5. It is further shown that the force storage 8 acts on another free loop 17 consisting of the stroke 10 shown in Figures 1 to 5 and the corresponding counter stroke 11 and that this free loop 17 acts on the Maltese 14 by delaying the action of the reel 13 shown in Figures 1 to 5. The following is a load switch housing 19 enclosing the load switch 18 and including a switch 20 which is operated continuously by the drive shaft 1 to the load-free pre-dial of the new winding socket to which it is to be switched.

Figure 7 shows a switch sequence of a load step switch according to the invention. The upper part shows the sequence when a switch is made from a winding connection n to a new winding connection n+1. It can be seen that at the beginning of a switch operation the drive shaft 1 rotates continuously and after a certain angle of rotation begins to move the switch 20 from the previous one to the new winding connection. After this operation is completed and the switch 20 has reached its new position, the current 18 spring switches are actuated - this is done by the most repeated power supply. Finally, after the switch has already been actuated, the drive shaft 1 continues to rotate continuously under a certain angle of rotation.

Figure 8 shows a switch sequence in the opposite direction of rotation of the drive shaft, i.e. from the n+1 socket back to the n socket. The corresponding directions of movement of the drive shaft 1 are each represented by an arrow in Figures 7 and 8.

In general, the invention allows the separate load switch 18 to be operated in a simple manner, both several times in succession in the same direction of rotation of drive shaft 1 and alternately in reverse of drive shaft 1.

Claims (4)

1. On-load tap changer for uninterrupted changeover between winding taps of a tapped transformer, comprising a separate selector for power-free preselection of the winding tap which is to be switched over to, further comprising a separate load changeover switch for the actual load changeover from the previous to the preselected new winding tap and further comprising an energy store with at least one energy store spring which for each load changeover is initially stressed by a rotating drive shaft and after triggering thereof abruptly actuates the load changeover switch, characterised in that the drive shaft (1) is operatively connected with a gearwheel (3) by which the energy store (8) can be stressed, a first mechanical freewheel (16) is provided between the gearwheel (3) and energy store (8) in such a manner that the energy store (8) can be stressed with a delay in time and the at least one triggered energy store spring (9) of the energy store (8) acts on a further mechanical freewheel (17), which in turn engages in a step transmission, particularly a Geneva gear (13, 14), for actuation of the load changeover switch (18), in such a manner that the load changeover switch (18) is in turn actuable with a delay in time.
2. On-load tap changer according to claim 1, characterised in that arranged on the gearwheel (3) is an abutment (4) which so co-operates with a further abutment (5a) on an intermediate shaft (6) rotatable independently of the drive shaft (1) that the abutment (4) and further abutment (5a) form the first mechanical freewheel (16), that the triggered energy store spring (9) acts on the intermediate shaft (6), that in addition arranged on the intermediate shaft (6) is a further abutment (10) which so co-operates with a counter-abutment (11) on an independently rotatable drive output wheel (12) that the further abutment (10) and counter-abutment (11) form the second mechanical freewheel (17) and that the drive output wheel (12) actuates the load changeover switch (18) by way of the step transmission.
3. On-load tap changer according to claim 2, characterised in that the drive output wheel (12) comprises a roller (13) which so engages in a Geneva wheel (14) that the roller (13) and Geneva wheel (14) form the step transmission.
4. On-load tap changer according to any one of claims 1 to 3, characterised in that the at least one energy store spring (9) is fixed at one end and its other, free end is mechanically connected with the abutment (5a) at the intermediate shaft (6), and the at least one energy store spring (9) can be stressed when the intermediate shaft rotates.