On-load tap changer

Abstract

A load tap changer (1) for load switching without interruption, comprising a first module (20) having a first module shaft (22), a second module (40) having a second module shaft (42), the first module shaft (22) actuating the first module (20), the second module shaft (42) actuating the second module (40), the first and second module shafts (22, 42) being mechanically coupled to each other such that the first module shaft (22) drives the second module shaft (42) and the second module (40) is actuated in time offset with respect to the first module (20).

Description

Technical Field

[0001] The present invention relates to an on-load tap changer for uninterrupted load switching between different winding taps of a tap changer transformer. Background Technology

[0002] On-load tap changers are known in the prior art and mostly consist of a load converter and a selector. The load converter—along with a vacuum switching tube and a switching resistor—is arranged in a container. The selector is constructed of multiple rods arranged in a circle. Contacts are arranged in different layers on these rods, which serve as the connection terminals for the various stages of the regulating winding. Inside the selector, two selector arms are fixed to a switch post. These selector arms are in contact with the contact points on these rods. The load converter and the selector are connected to each other via a drive mechanism.

[0003] The operation of the on-load tap changer is achieved by means of a driver, which on the one hand tensions the spring accumulator to operate the load converter, and on the other hand moves the selector arm to pre-select the contacts to be wired. Here, not only in the load converter but also in the selector, the contacts and switching devices of all three phases are always operated simultaneously. This inevitably causes torque peaks because the same contacts of each phase must be operated at the same time. The driver, spring accumulator, and actuator must be designed so that they can overcome torque peaks. Summary of the Invention

[0004] The objective of this invention is to provide an on-load tap changer that produces significantly smaller torque peaks during operation, is simple and compact in construction, and hereby ensures reliable function.

[0005] This task is accomplished using an on-load tap changer as described in this invention.

[0006] According to a first aspect, the present invention provides an on-load tap changer for uninterrupted load switching between different winding taps of a tap changer transformer, the on-load tap changer comprising:

[0007] - The first module having the first module axis;

[0008] - A second module with a second module axis, wherein:

[0009] - The first module's axis controls the first module.

[0010] - The second module's axis controls the second module.

[0011] - The first and second module shafts are mechanically connected to each other, such that the first module shaft drives the second module shaft and the second module is manipulated in a time-staggered manner relative to the first module.

[0012] By dividing the on-load tap changer into modules and staggering mechanical connections between these modules, the peak torque is significantly reduced. This is achieved by driving the elements to be operated in each module of the on-load tap changer simultaneously, but operating them sequentially with slight staggering. This staggering is just large enough that no negative electrical interaction occurs between the phases of the tap changer, but the resulting torque spikes are formed with slight staggering. This allows for the use of significantly simpler and more advantageous motors. Furthermore, the various parts of the drive shaft can be made smaller because they only need to withstand smaller torque loads. This also positively impacts the overall price of the switch. Without the mechanically staggered connections, the same elements are moved or operated simultaneously in each module. The required forces would be additive, necessitating a driver with corresponding power.

[0013] Each module can be designed in any way as needed and may include, for example, module shafts. The first module shaft of the first module is mechanically connected to the second module shaft of the second module. Here, these module shafts are mechanically connected to each other in a staggered manner, so that the manipulation of each module is performed at a staggered time. In other words, although the two module shafts start to rotate simultaneously, the effects of the two modules on the components in these modules (the opening and closing of the vacuum switch tubes) occur at staggered times.

[0014] These module shafts can be connected to each other in any way as needed, such as via isolation bars, isolation shafts, or chains.

[0015] These modules, and especially the misalignment between their axes, can be designed in any way as needed, for example, by designing misaligned connecting pins on the module axis and the same design of the isolation axis, or on the isolation axis with misaligned receiving parts and the same module axis. How the misalignment between the module axes is ultimately achieved is not the key point here.

[0016] The load converter can be designed in any way as needed and may include, for example, at least two or more modules. These modules are each assigned to one phase of the tap changer.

[0017] Each module can be designed in any manner as needed and, for example, includes at least one load converter and a selector. Here, the load converter may include at least one switching element and a current-limiting element. The at least one switching element may be designed as a vacuum switching tube or a simple mechanical switch. The current-limiting element is preferably a resistor, a choke, or a current-associated resistor. The selector has at least one selector arm, preferably two selector arms as a fine selector and / or one preselector arm as a preselector.

[0018] Each module shaft can be designed in any manner as needed, and for example, has a connecting pin, bolt, key, or any other connecting element at each end. Here, these connecting pins are not axially parallel and are preferably arranged with a maximum offset of 15 degrees from each other. These connecting pins, bolts, or keys can only be inserted into or pass through the entire module shaft on one side.

[0019] Each module shaft can be designed in any manner as needed, and for example, has a first connecting pin at a first end and a second connecting pin at a second end. The first connecting pin may run along a first axis A and the second connecting pin may run along a second axis B, wherein axes A and B are not axially parallel and are preferably arranged at an angle offset by a maximum of 15 degrees.

[0020] The driver can be designed in any manner as needed and may include, for example, at least one motor and / or drive mechanism. The motor may be designed as a synchronous motor with a multi-turn absolute encoder or a DC motor with microswitches.

[0021] It can be specified that these module shafts and these isolation shafts are connected via couplings and / or couplings having multiple coupling housings.

[0022] It can be specified that the motor is directly connected to the drive shaft, or indirectly connected to the isolation shaft or the first module shaft of the on-load tap changer via a transmission mechanism, gear transmission, bevel gear transmission or connecting rod. Attached Figure Description

[0023] The invention and its advantages will then be described in more detail with reference to the accompanying drawings. Wherein:

[0024] Figure 1 A first embodiment of an on-load tap changer is shown;

[0025] Figure 2a A detailed view of the module axis is shown;

[0026] Figure 2b A front view of the module axis is shown;

[0027] Figure 3 Multiple module shafts of an on-load tap changer according to the present invention are shown;

[0028] Figure 4 Another detailed view of the module axis is shown. Detailed Implementation

[0029] The same reference numerals are used for elements that are identical or function identically in this invention. Furthermore, for clarity, only the reference numerals necessary for describing the respective figures are shown in the various figures. The embodiments illustrated represent only examples of how on-load tap changers according to the invention can be designed, and therefore do not represent a closed limitation of the invention.

[0030] Figure 1 A schematic structure of an on-load tap changer 1 according to the invention is shown. The on-load tap changer has a first module 20, a second module 40, and a third module 60. Each of modules 20, 40, and 60 is assigned to one phase of a tap changer transformer. The first module 20 has a first module shaft 22. The first module shaft 22 is connected or coupled to a driver 2 at its first end 23. The driver 2 is designed as a motor driver with or without a transmission mechanism, and is preferably mechanically connected to the first end 23 of the first module shaft 22 via a first isolation shaft 21. The first module 20 has a load converter 30 and a selector 35. The load converter 30, and in particular its vacuum switching tubes, are operated directly via the first module shaft 22. Here, two cam disks 32 are mounted on the first module shaft 22, and these cam disks open and close the vacuum switching tubes as they rotate. Furthermore, a first bevel gear 36 is arranged on the first module shaft 22, which drives a second bevel gear 37, which in turn operates the respective selector arms of the selector 35. Therefore, when the first module shaft 22 is driven, the load converter 30 and the selector 35 are operated in a specific sequence; the first module 20 of the on-load tap changer 1 is operated.

[0031] The on-load tap changer 1 also has a second module 40 and a third module 60. These three modules 20, 40, and 60 are constructed identically to each other. These three modules are also mechanically connected to each other via second and third isolation shafts 41 and 61. The driver 2 drives the first module 20 via the first isolation shaft 21, the first module 20 drives the second module 40 via the second isolation shaft 41, and the second module 40 drives the third module 60 via the third isolation shaft 61. The second and third modules 40 and 60 also respectively have load converters 50 and 70, selectors 55 and 75, and module shafts 42 and 62. The corresponding selectors 55 and 75 are driven via corresponding bevel gears 56, 57, 76, and 77.

[0032] Figure 2aA detailed view of a first module shaft 22 is shown, which has a first connecting pin 24 at its first end 23. The first module shaft 22 is connected to the driver 2 via this first connecting pin 24, for example, via a first isolating shaft 21. The first module shaft 22 also has a second connecting pin 26 at its second end 25. The second connecting pin 26 is not arranged axially parallel to the first connecting pin 24 on the module shaft 22. In other words, the second connecting pin 26 is offset from the first connecting pin 24 by a few degrees. As an alternative to the connecting pin, a bolt, key, or any other connecting element can be used. The connecting pin may extend only on one side or extend from one side to an opposite second side.

[0033] Figure 2b A front view of module shaft 22 is shown. Axis A is intended to indicate the orientation of the first connecting pin 24. Axis B indicates the orientation of the second connecting pin 26. Axis A and B are arranged offset from each other by an angle W1, preferably a maximum of 15 degrees. If the second module shaft 42 is now placed behind and connected to the first module shaft 22, the first connecting pin 44 of the second module shaft 42 will be axially parallel to the axis B of the second connecting pin 26 of the first module shaft 22. Each module shaft 22, 42, 62 is designed identically, that is, the second connecting pins 26, 46, 66 are arranged offset from the corresponding first connecting pins 24, 44, 64. Axis C indicates the orientation of the second connecting pin 46 (not shown here) of the second module shaft 42. The angle W2 between axes B and C is the same as the angle W1 between axes A and B.

[0034] Figure 3 Detailed views of two interconnected module shafts, specifically the first module shaft 22 and the second module shaft 42, are shown. A first connecting pin 24 on the first end 23 of the first module shaft 22 is offset relative to a second connecting pin 26 on the second end 25. The first end 23 of the first module shaft 22 is connected to the driver 2 via a first isolating shaft 21. The connection between the first isolating shaft 21 and the first module shaft 22 is achieved by means of a coupling 19, which preferably has two coupling housings. However, any type of coupling can be used. The second end 25 of the first module shaft 22 is connected to the first end 43 of the second module shaft 42 via a second isolating shaft 41. As is now clear, the first connecting pins 24 and 44 of the corresponding module shafts 22 and 42 are connected to each other offset from one another. Once the driver 2 begins to rotate or drives the first isolating shaft 21, the other shafts also rotate accordingly. However, the operation of modules 20, 40, and 60 is staggered because the cam disks of the second module 40 or the third module 60, as well as the first bevel gear, are arranged staggered relative to the cam disks and the first bevel gear of the first module 20.

[0035] Isolating shafts 41 and 61 are designed to be identical, meaning that the couplings 19 at their respective ends are the same. Alternatively, these isolating shafts can also have staggered couplings at their respective ends as an alternative to module shafts with staggered connecting pins. This also achieves a staggered mechanical connection between these modules. These modules are simultaneously and jointly driven, but manipulated with a time delay.

[0036] Figure 4 A detailed view of one of the module shafts 20, 40, and 60, particularly the first module shaft 20, is shown, while the second and third module shafts 40 and 60 are constructed identically. Two cam disks 32 for operating the vacuum switch tube and a first bevel gear 36 for operating the selector 35 are arranged on module shaft 20. Within a 360-degree rotation of module shaft 20, the operation of the load converter 30 and the selector 35 is performed. Depending on the position of module shaft 20, various actions in the on-load tap changer, such as opening or closing the vacuum switch tube in the switching sequence, are performed at specific points in time. Once at least two module shafts 40 and 60 are staggered with each other, the actions in the second module 40 are correspondingly slightly staggered with those in the first module 20; finally, modules 20, 40, and 60 are constructed identically. Here, although the second module 40 is driven simultaneously with the first module 20, the actual operation of the second module 40 (opening or closing of the vacuum switch tube) is staggered in time.

[0037] As an alternative to the modular shafts 20, 40, and 60 with staggered connecting pins, these isolation shafts may also have staggered receiving portions at both ends. In this way, these modular shafts are also mechanically connected to each other in a staggered manner.

[0038] List of reference numerals

[0039] 1 On-load tap changer

[0040] 2 drives

[0041] 19 coupling

[0042] 20 Module 1

[0043] 21 First Isolation Axis

[0044] 22 First Module Axis

[0045] The first end of 2322

[0046] 2422 First connecting pin

[0047] The second end of 2522

[0048] 2622 Second connecting pin

[0049] 30 load converter

[0050] 32 Cam Disc

[0051] 35 selector

[0052] 36 First bevel gear

[0053] 37 Second bevel gear

[0054] 40 Module 2

[0055] 41 Second Isolation Shaft

[0056] 42 Second Module Axis

[0057] The first end of 4342

[0058] 4442's first connecting pin

[0059] The second end of 4542

[0060] 4642 Second connecting pin

[0061] 50 load converter

[0062] 55 selector

[0063] 60 Module 3

[0064] 61 Third Isolation Axis

[0065] 62 Third Module Axis

[0066] The first end of 6362

[0067] 6462 First connecting pin

[0068] The second end of 6562

[0069] 6662's second connecting pin

[0070] 70 load converter

[0071] 75 selector

Claims

1. An on-load tap changer (1) for uninterrupted load switching, the on-load tap changer comprising: - A first module (20) having a first module axis (22); - Second module (40) with second module axis (42). in: - The first module axis (22) manipulates the first module (20). - The second module axis (42) manipulates the second module (40). - The first module shaft (22) and the second module shaft (42) are mechanically connected to each other, such that the first module shaft (22) drives the second module shaft (42) and the second module (40) is operated in a time-staggered manner relative to the first module (20), wherein the torque peak during operation is reduced by dividing the on-load tap changer into the first module and the second module and the staggered mechanical connection of the first module and the second module. - Each module is assigned to one phase of the tap changer. - Each module has a load converter and selector.

2. The on-load tap changer (1) according to claim 1, wherein, - The driver (2) drives the first module axis (22).

3. The on-load tap changer (1) according to claim 1, wherein, - A third module (60) with a third module axis (62) is provided. - The third module shaft (62) manipulates the third module (60) and the second module shaft (42) and the third module shaft (62) are mechanically connected to each other, such that the second module shaft (42) drives the third module shaft (62) and the third module (60) is manipulated in a time-staggered manner relative to the second module (40).

4. The on-load tap changer (1) according to claim 3, wherein, - The modules are connected to each other via isolation axes.

5. The on-load tap changer (1) according to any one of claims 1 to 3, wherein, - Each module shaft has a first connecting pin (24, 44, 64) and a second connecting pin (26, 46, 66); and - The first connecting pins (24, 44, 64) are arranged in a staggered manner relative to the second connecting pins (26, 46, 66).

6. The on-load tap changer (1) according to claim 4, wherein, - The first module shaft (22) is connected to the second module shaft (42) via a second isolation shaft, and the second module shaft (42) is connected to the third module shaft (62) via a third isolation shaft.

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