Patent Application
20230360871
The invention relates to a compact vacuum interrupter. Vacuum interrupters are used in low-, medium- and high-voltage switchgear.
To conduct currents, a vacuum interrupter requires what is referred to as a current path, which conducts the current to the contact system in the vacuum. This current path is usually divided into two regions, a stationary part - fixed-contact current path, that is to say a fixed contact - and a movable part - movable-contact current path, that is to say a movable contact. The current path components usually consist of the same material, for example copper. The homogeneous material selection is deviated from in particular for what are referred to as contact disks, which must have sufficient resistance to arc events. In the case of vacuum interrupters, interrupters in short, that can conduct rated currents, a copper material, in particular oxygen-free copper, is usually selected. In the case of interrupters in which the current only commutates into the interrupter to disconnect it, it is also possible to use, for example, stainless steel in the two current path components.
In the case of interrupters optimized in terms of material use, which do not conduct rated current but very frequently interrupt a current at least in a test situation, the thermal loading caused by the high input of arc energy is relatively high. In this application, the use of a current path of stainless steel can be advantageous from a mechanical perspective.
Since, however, in common switching situations thermal limits are quickly reached, a sufficiently solid design in copper is generally preferred.
As an alternative, the prior art, such as for example DE 102016213294 A1, has also disclosed stiffened contact rods, wherein the contact rods as electrical conductors comprise the same materials, but the one or more contact rods are stiffened with another material. However, such a combination is complex to produce and expensive.
It is now an object of the invention to overcome the disadvantages of the prior art and to provide a compact vacuum interrupter with reduced use of material.
The object is achieved by independent Claim 1 and the claims dependent thereon.
A first exemplary embodiment relates to a compact vacuum interrupter having an insulator element, a movable-contact connection, a fixed-contact connection, a movable contact, and a fixed contact, wherein the movable contact has a movable-contact rod and a movable-contact contact element, and wherein the fixed contact has a fixed-contact rod and a fixed-contact contact element, wherein the movable contact is made with a first material and the fixed contact is made with a second material, wherein the first material is mechanically stronger than the second material.
Here, a mechanically stronger material is understood to mean a material which is more resistant to mechanical stresses, for example is stiffer and/or harder, that is to say in particular is more resistant to deformations. The combination of a good electrical conductor and good heat conductor as first material on the fixed-contact side and a mechanically stronger material on the movable-contact side makes it possible to reduce the diameter of the vacuum interrupter, without adversely affecting the switching power. It is also possible for the drive for the movable contact to have a smaller, that is to say less efficient design, since the mass of the movable contact is reduced, or alternatively for it to be switched more quickly with the same energy.
In particular, it is preferred if what is involved is a compact vacuum interrupter for low-, medium- and/or high-voltage switches. It is also preferred if what is involved is a compact vacuum interrupter for low-, medium- and/or high-voltage tap changers. In this respect, the medium- and high-voltage applications are particularly preferred.
It is also preferred for the vacuum interrupter to be suitable for operation in a gas chamber with a gas pressure of more than 1 bar. In particular, it is preferred for the gas in the gas chamber to be formed from air constituents, in particular nitrogen and/or carbon dioxide, or contain a ketone or a fluoronitrile, sulfur hexafluoride, an olefin, polyfluoroolefin, or a hydrofluoroolefin.
It is further preferred for the vacuum interrupter to be configured to act as secondary current path in a switchgear, that is to say configured to switch switch-off currents.
It is preferred for the movable-contact rod to be made with a first material and the fixed-contact rod to be made with a second material, and the movable-contact contact element and the fixed-contact contact element to be made from a third material, wherein the first material is mechanically stronger than the second material and the third material is a material which is optimized in terms of properties under arc conditions.
It is also preferred for the second material to be copper or a copper alloy.
It is further preferred for the first material to be a chromium-nickel alloy or steel alloy, in particular stainless steel alloy.
It is also preferred for the third material to be a copper alloy made with tungsten and/or chromium and/or carbon.
It is also preferred for the movable-contact rod to have a diameter and for the movable-contact rod, in a first movable-contact rod region, to have a narrowing, wherein the narrowing reduces the diameter.
It is further preferred for the narrowing to reduce the diameter of the movable-contact rod by 5% to 25%.
It is also preferred for the narrowing to reduce the diameter of the movable-contact rod by 10% to 20%.
It is also preferred for the first movable-contact rod region with the narrowing to be arranged in the compact vacuum interrupter such that the first movable-contact rod region is arranged within the insulator element. Within the insulator element means that the insulator element surrounds, in particular annularly surrounds, the first movable-contact region.
It is further preferred for one, two or more shield elements to be arranged between the insulator element and the first movable-contact rod region. In this respect, the shield elements serve both as damping protection for the insulator and as field control.
A further exemplary embodiment relates to a switchgear having a compact vacuum interrupter according to one or more of the above statements relating to the first exemplary embodiment.
It is preferred if the compact vacuum interrupter is arranged in a secondary current path and is configured to switch off rated currents.
It is also preferred for one or more compact vacuum interrupters to be arranged in a tap changer, in particular arranged in a tap changer for transformers.
The invention will be explained by way of example below with reference to figures.
In the embodiment shown here, a respective metal connecting piece, which can vary in terms of shape and length, is arranged between the insulator 10 and the fixed-contact connection 30 and between the insulator 10 and the movable-contact connection 20.
Furthermore, the preferred embodiment shown here additionally has a narrowing of the movable-contact rod 410 in a first movable-contact rod region 415, in which the diameter 412 of the preferably cylindrical movable-contact rod 410 is reduced, in particular by 5% to 25%, particularly preferably 10% to 20%.
This narrowing makes it possible to reduce the diameter of the insulator 10 further, in particular to reduce it further than selecting the first material as mechanically stronger than the second material alone would. Furthermore, in spite of the reduced diameter of the insulator, it is possible to arrange shields 412 between the insulator 10 and the movable-contact rod 410.
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| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2020 212 377.2 | Sep 2020 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/075066 | 9/13/2021 | WO |
