Patent Application
20220415587
The invention relates to an on-load tap changer for uninterrupted diverter switch operation between different winding taps of a tap changing transformer.
On-load tap changers usually consist of a diverter switch and a selector. The diverter switch, with the vacuum interrupters and the transition resistors, is arranged in a vessel. The selector is made up of a multiplicity of bars arranged in a circle. Contacts which serve as connections for the individual taps of the tap windings are arranged at different levels on said bars. Inside the selector, two selector arms are attached to a switching column. They make contact with the contacts on the bars. Diverter switch and selector are connected to each other via a gear unit.
The on-load tap changer is actuated by means of a drive which, on the one hand, winds up a spring energy accumulator in order to actuate the diverter switch and, on the other hand, moves the selector arms in order to preselect the contacts to be switched. The contacts and switching means of all three phases are always actuated simultaneously both in the diverter switch and in the selector. This inevitably leads to torque peaks, since the same contacts of each phase have to be actuated at the same time. The drive, spring accumulator and gear unit have to be configured in such a way that they can handle the torque peaks.
In an embodiment, the present disclosure provides an on-load tap changer that is for uninterrupted diverter switch operation. The on-load tap changer includes: a first module having a first module shaft; and a second module having a second module shaft. The first module shaft is configured to actuate the first module. The second module shaft is configured to actuate the second module. The first module shaft and the second module shaft are mechanically coupled to one another in such a way that the first module shaft is configured to drive the second module shaft and the second module is configured to be actuated with a time delay with respect to the first module.
Subject matter of the present disclosure will be described in even greater detail below based on the exemplary figures. All features described and/or illustrated herein can be used alone or combined in different combinations. The features and advantages of various embodiments will become apparent by reading the following detailed description with reference to the attached drawings, which illustrate the following:
Embodiments of the present invention provide an on-load tap changer that generates significantly smaller torque peaks during actuation, has a simple and compact design, and at the same time ensures reliable operation.
According to a first aspect, the present invention provides an on-load tap changer for uninterrupted diverter switch operation between different winding taps of a tap changing transformer, comprising:
Torque peaks are significantly reduced by dividing the on-load tap changer into individual modules and mechanically coupling the latter with an offset. This is achieved in that, although the elements to be actuated of the modules of the on-load tap changer are driven simultaneously, they are actuated one after the other with a slight offset. The offset is just large enough that no negative electrical interactions occur between the individual phases of a tap changing transformer, but the torque increases that occur are slightly offset from one another. This enables the use of a significantly simpler and therefore more advantageous motor. Furthermore, the individual parts of the drive shaft can be made smaller since they have to withstand smaller torque loads. This also has a positive effect on the cost of the entire switch. Without a mechanically offset coupling, the same elements would be moved or actuated in each module at the same time. The required force would add up, and this would require a drive with corresponding power.
Each module can be designed in any way as required and can include a module shaft, for example. The first module shaft of the first module is mechanically coupled to the second module shaft of the second module. The module shafts are mechanically connected to one another with an offset from one another in such a way that the individual modules are actuated with an offset from one another. In other words, although the two module shafts start rotating at the same time, the effect thereof (opening and closing of vacuum interrupters) on the elements in the modules takes place with a time delay.
The module shafts can be connected to one another in any way as required, for example via insulating bars, insulating shafts or chains.
The offset between the modules and in particular between the module shafts can be designed in any way as required, for example as offset connecting pins on the module shafts and identically designed insulating shafts or insulating shafts with offset receptacles and identical module shafts. How the offset between the module shafts is ultimately realized is irrelevant.
The diverter switch can be designed in any way as required and can, for example, comprise at least two or more modules. The modules are each assigned to a phase of a tap changing transformer.
Each module can be designed in any way as required and can, for example, comprise at least one diverter switch and one selector. The diverter switch can include at least one switching element and one current-limiting element. The at least one switching element can be designed as a vacuum interrupter or as a simple mechanical switch. The current-limiting element is preferably a resistor, a reactor or a current-dependent resistor. The selector has at least one selector arm, preferably two selector arms as a tap selector and/or a change-over selector arm as a change-over selector.
Each module shaft can be designed in any way as required and, for example, can have a connecting pin, bolt, feather keys or any other connecting element at each end. The connecting pins are not axially parallel and are preferably offset from one another by a maximum of 15 degrees. The connecting pins, bolts or feather keys can be inserted only on one side or extend through the entire module shaft.
Each module shaft can be designed in any way as required and, for example, can have 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 the axes A and B are not axially parallel and are preferably offset by an angle of a maximum of 15 degrees.
The drive can be designed in any way as required and, for example, can include at least one motor and/or a gear unit. The motor can be designed as a synchronous motor with a multi-turn absolute encoder or as a DC motor with microswitches.
Provision can be made for the module shafts and the insulating shafts to be connected via couplings and/or couplings with a plurality of coupling brackets.
Provision can be made for a motor to be connected directly to the drive shaft or indirectly to the insulating shaft or the first module shaft of the on-load tap changer via a gear unit, bevel gear or linkage.
Identical reference signs are used for elements of the invention that are identical or functionally identical. Furthermore, for the sake of clarity, each of the individual figures contains only those reference signs necessary for the description of said figure. The illustrated embodiments merely illustrate examples of how the on-load tap changer according to the invention can be designed and therefore do not represent a final delimitation of the invention.
Furthermore, the on-load tap changer 1 has a second module 40 and a third module 60. The three modules 20, 40, 60 are constructed identically to one another. The three modules are also mechanically coupled to one another via a second and a third insulating shaft 41, 61. The drive 2 drives the first module 20 via the first insulating shaft 21, the first module 20 drives the second module 40 via the second insulating shaft 41, and the second module 40 drives the third module 60 via the third insulating shaft 61. The second and the third module 40, 60 each also have a diverter switch 50, 70, a selector 55, 75 and module shafts 42, 62. The respective selectors 55, 75 are driven via respective bevel wheels 56, 57, 76, 77.
The insulating shafts 41, 61 are configured identically here, i.e. the couplings 19 at the respective ends are identical. As an alternative to the module shafts with offset connecting pins, the insulating shafts can also have offset couplings at the respective ends. This also results in an offset mechanical coupling of the modules. The modules are driven simultaneously and together, but actuated with a time delay.
As an alternative to the module shafts 20, 40, 60 with offset connecting pins, the insulating shafts could also have offset receptacles at the two ends. The module shafts are therefore also mechanically connected with an offset from one another.
While subject matter of the present disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. Any statement made herein characterizing the invention is also to be considered illustrative or exemplary and not restrictive as the invention is defined by the claims. It will be understood that changes and modifications may be made, by those of ordinary skill in the art, within the scope of the following claims, which may include any combination of features from different embodiments described above.
The terms used in the claims should be construed to have the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article “a” or “the” in introducing an element should not be interpreted as being exclusive of a plurality of elements. Likewise, the recitation of “or” should be interpreted as being inclusive, such that the recitation of “A or B” is not exclusive of “A and B,” unless it is clear from the context or the foregoing description that only one of A and B is intended. Further, the recitation of “at least one of A, B and C” should be interpreted as one or more of a group of elements consisting of A, B and C, and should not be interpreted as requiring at least one of each of the listed elements A, B and C, regardless of whether A, B and C are related as categories or otherwise. Moreover, the recitation of “A, B and/or C” or “at least one of A, B or C” should be interpreted as including any singular entity from the listed elements, e.g., A, any subset from the listed elements, e.g., A and B, or the entire list of elements A, B and C.
1 On-load tap-changer
2 Drive
19 Coupling
20 First module
21 First insulating shaft
22 First module shaft
23 First end of 22
24 First connecting pin of 22
25 Second end of 22
26 Second connecting pin of 22
30 Diverter switch
32 Cam disks
35 Selector
36 First bevel wheel
37 Second bevel wheel
40 Second module
41 Second insulating shaft
42 Second module shaft
43 First end of 42
44 First connecting pin of 42
45 Second end of 42
46 Second connecting pin of 42
50 Diverter switch
55 Selector
60 Third module
61 Third insulating shaft
62 Third module shaft
63 First end of 62
64 First connecting pin of 62
65 Second end of 62
66 Second connecting pin of 62
70 Diverter switch
75 Selector
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2019 130 460.1 | Nov 2019 | DE | national |
This application is a U.S. National Phase application under 35 U.S.C. § 371 of International Application No. PCT/EP2020/075629, filed on Sep. 14, 2020, and claims benefit to German Patent Application No. DE 10 2019 130 460.1, filed on Nov. 12, 2019. The International Application was published in German on May 20, 2021 as WO 2021/094013 A1 under PCT Article 21(2).
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/075629 | 9/14/2020 | WO |
