Patent Grant
7262362
The present application claims priority under 35 U.S.C. 119 to European Application No. 04405115.9 filed Feb. 27, 2004, the contents of which are hereby incorporated by reference in their entirety.
1. Technical Field
The invention relates to the field of high-voltage switch technology. It relates to a high-voltage switching device and to a method for separation of foreign body particles in a high-voltage switching device as claimed in the precharacterizing clause of the independent claims, and to a high-voltage installation as claimed in claim 10.
2. Prior Art
A high-voltage switching device such as this is known, for example, from DE 41 20 309, which describes a particle trap which is in the form of a connecting stub that is closed by a cover and whose inside is provided with a protective coating. A particle trap such as this is intended for use in high-voltage switching devices which have grounded, metallic encapsulation enclosing a live active part. Foreign body particles which are located within the encapsulation and can reduce the dielectric strength of the high-voltage switching device are intended to be collected within the particle trap. The foreign body particles which have been separated in this way are intended to remain within the particle trap, so that this results in the high-voltage switching device having a sufficiently high dielectric strength which is not reduced by these foreign body particles.
A high-voltage switching device such as this has the disadvantage that its dielectric strength and hence its operational reliability are not ensured well during operation.
One object of the invention is therefore to provide a high-voltage switching device of the type mentioned initially which does not have the disadvantages mentioned above. One particular aim is to provide a high-voltage switching device which has high operational reliability.
This object is achieved by an apparatus and a method having the features of the independent patent claims.
The high-voltage switching device according to the invention, which can be used in at least one installation position and has metallic encapsulation, containing a switching gap and a particle trap for holding foreign body particles, is characterized in that in the at least one installation position, the particle trap is arranged vertically underneath the switching gap, and in that, in the at least one installation position, an isolator part is provided, which has a surface that is aligned essentially horizontally and faces the interior of the high-voltage switching device, with a metallic wall, which is higher than the particle trap, being arranged between the isolator part and the particle trap.
This results in the high-voltage switching device having high operational reliability and little susceptibility to defects. The probability of faults and flashovers is reduced.
An isolator part such as this may have the object of supporting the active part or parts of it and/or of isolating the internal volume of the high-voltage switching device from the internal volume of an adjacent component. Isolator parts in high-voltage switching devices are subject to high dielectric loads and are thus particularly sensitive to faults. An isolator part having a surface which is aligned essentially horizontally and faces the interior of the switching device is particularly susceptible to foreign body particles which are arranged on the surface.
A metallic wall or an electrically conductive projection between the isolator part and the particle trap can, on the one hand, prevent foreign body particles which land on the particle trap side from moving in the direction of the isolator part, while on the other hand ensuring that there is a low electrical field strength in the area of the particle trap.
The foreign body particles which can interfere with the dielectric strength within a high-voltage switching device include electrically conductive and non-conductive particles. Particles such as these arise, for example, during the production of the high-voltage switching device and must be removed as completely as possible from the interior of the encapsulation before the high-voltage switching device is closed and used. Foreign body particles can also enter whenever the high-voltage switching device is opened and closed. In particular, however, foreign body particles can also arise during operation of the high-voltage switching device. In general, a high-voltage switching device has at least one moving contact piece which forms a detachable contact with a further contact piece. The wear which occurs as a result of movement of the moving contact piece means that foreign body particles can be produced. In particular, a particularly large number of foreign body particles are thus produced in switching gaps as a result of the friction between the contact pieces. A particularly large number of foreign body particles are also produced when an arc is formed in the switching gap. If the field strength is sufficiently high, foreign body particles can be moved by the forces which are produced by the electrical field and act on the foreign body particles, thus leading to flashovers, particularly at points which are subject to particularly high dielectric loads.
Gravitation results in the foreign body particles that are produced in this way preferably moving downwards (in particular when switching takes place with no voltage), and thus preferably land vertically underneath the switching gap. A particle trap arranged there can hold these foreign body particles (and thus a particularly large number of foreign body particles), thus improving the operational reliability of the high-voltage switching device.
For the purposes of this application, high-voltage switching devices include high-voltage and high-power switches, switches with or without arc quenching, disconnectors, grounding devices as well as further switching devices from the field of high-voltage technology.
A high-voltage switching device such as this may be intended for use in one or more installation positions. The location of the particle trap according to the invention therefore depends on the installation position or positions.
A particle trap advantageously always contains an area which is subject to little dielectric load such that foreign body particles can no longer leave the particle trap during operation of the high-voltage switching device. The particle trap is advantageously designed in the form of a vessel, thus making it harder for the foreign body particles to leave the particle trap during operation of the high-voltage switching device. A particle trap advantageously contains a metallically surrounding area with a depression.
The electrical field strength in the particle trap should advantageously be lower, typically by two orders of magnitude and advantageously by three or more orders of magnitude, than the electrical field strength in areas within the encapsulation which are subject to severe dielectric loads. This ensures reliable separation of the foreign body particles, even during switching processes. The electrical field strength in the particle trap is preferably less than 10 kV/cm.
In one advantageous embodiment, the particle trap contains a viewing window. The viewing window allows an optical check of the presence, the nature and the quantity of foreign body particles during operation. This visual check can be used in order to identify or to confirm the need for maintenance or servicing without having to open the encapsulation of the high-voltage switching device.
In one advantageous embodiment, the high-voltage switching device can be used in at least one second installation position and has a second particle trap, with the second particle trap being arranged vertically underneath the switching gap in the at least one second installation position.
This results in greater flexibility for use of the high-voltage switching device, and high operational reliability in the second installation position of the high-voltage switching device, as well.
In the situation in which the high-voltage switching device has two or more switching gaps, the second particle trap can also be arranged vertically underneath another switching gap and, in particular, one particle trap may also in each case be provided for each switching gap and for each installation position, in which case some of these particle traps may also be identical.
One of the particle traps may advantageously be formed essentially by a contact tulip, in particular a fixed contact tulip, in the high-voltage switching device. This is advantageous because the fixed contact tulip is naturally directly adjacent to the switching gap, so that particles which are produced there are trapped at the point at which they occur. Furthermore, the contact tulip forms a Faraday cage, so that there is no field in the internal area surrounded by the contact tulip.
In one advantageous embodiment, the high-voltage switching device is a disconnector, in particular a disconnector with a contact tube as the moving contact, and advantageously with a visible disconnecting gap as the switching gap. The high-voltage switching device may also be a grounding device or a disconnector which acts as a grounding device and whose grounding device disconnecting gap represents the switching gap. It is particularly advantageous for the high-voltage switching device to be a disconnector/grounding device with a disconnecting gap on the ground side and a disconnecting gap on the high-voltage side.
The or one of the particle traps may advantageously be formed essentially by an opening for holding the contact tube of the disconnector or grounding device disconnector. This is advantageous because the opening is naturally directly adjacent to the switching gap, so that particles which are produced there are trapped directly at the point at which they occur. Furthermore, the opening may essentially form the interior of a Faraday cage, so that there is no field in the opening.
A viewing window in the particle trap can advantageously at the same time be in the form of a viewing window for visual access to a visible disconnecting gap. In this case, the functions of the viewing window are on the one hand to make the visible disconnecting gap visually accessible, and on the other hand to make the particle trap and the foreign body particles in it visually accessible. This dual function of the viewing window simplifies the design of the high-voltage switching device. In comparison to the standard vertical alignment of the viewing window for visual access to a visible disconnecting gap, a horizontal alignment of the viewing window, which is advantageous for particle assessment, takes account of the disadvantage of generally poorer accessibility of the viewing window for someone looking through the viewing window.
In one preferred embodiment, the high-voltage switching device is a disconnector/grounding device with a disconnecting gap on the ground side and a disconnecting gap on the high-voltage side, which has a contact tube and can be used in at least one first, one second and one third installation position, with
A high-voltage switching device such as this can be used in a highly flexible manner since it has at least three installation positions and is nevertheless highly operationally reliable by virtue of the respective particle traps.
A high-voltage switching device according to the invention may be part of a high-voltage installation according to the invention.
The method according to the invention for separation of foreign body particles in a high-voltage switching device which can be used in at least one installation position and has a switching gap and a particle trap for holding the foreign body particles is characterized in that the foreign body particles are separated in a particle trap which is arranged vertically underneath the switching gap in the at least one installation position, with an isolator part having a surface which is aligned essentially horizontally and faces the interior of the high-voltage switching device being provided in the at least one installation position, and with a metallic wall, which is higher than the particle trap, being arranged between the isolator part and the particle trap.
The other advantageous methods according to the invention result from the advantageous apparatuses according to the invention.
Further preferred embodiments and advantages will become evident from the dependent patent claims and from the figures.
The subject matter of the invention will be explained in more detail in the following text with reference to preferred exemplary embodiments which are illustrated in the attached drawings in which, schematically and in the form of sections:
The reference symbols used in the drawings, and their meanings, are listed in summarized form in the List of Reference Symbols. In principle, identical parts and parts having the same effect are provided with the same reference symbols in the figures. The described exemplary embodiments represent examples of the subject matter of the invention and have no restrictive effect.
The grounding device/disconnector has metal encapsulation 10 which is filled with an insulating gas 12, preferably SF6. Alternatively, there could also be a vacuum within the encapsulation 10. Furthermore, the encapsulation 10 contains active parts, which are supported on an isolator part 8. A connecting piece 15 which is supported on a metal part 21 (internal fitting in the isolator part 8) which is provided in the isolator part 8 produces an electrical connection between the active part and the exterior. The connecting piece 15 supports a contact tube mount 14 to which a contact tube 6 is fitted which makes contact with the contact tube mount 14 by means of a spiral spring contact 20. The contact tube can be moved between three positions by means of a traveling nut 19 and a spindle 17 which is guided by means of a spindle guide 18. A different moving contact piece, for example in the form of a complete cylinder, could also be used instead of the contact tube. The spindle has an insulating shaft 16 in order to electrically isolate the traveling nut 19 from the encapsulation 10.
When the grounding device/disconnector is in a grounding position, an end 6b of the contact tube 6 on the ground side is held in an opening 7, and produces an electrical connection via spiral contacts 20 between the grounded encapsulation 10 and the metal part 21. An isolating gap 4′ on the ground side is thus bridged, while an isolating gap 4 on the high-voltage side is open. The opening 7 for holding the contact tube 10 is integrated in the encapsulation in
When the grounding device/disconnector is in a high-voltage position, a contact is formed between a contact tulip 5, to which high voltage is applied, and the metal part 21, by an end 6a of the contact tube 10 on the high-voltage side making contact with the contact tulip 5 by means of spiral spring contacts 20.
In the intermediate position illustrated in
For further details relating to the design and operation of the described grounding device/disconnector, reference should be made to the patent application by the inventors Daniel Bleiker, Bojan Pavlovic, Diego Sologuren, Walter Holaus and Martin Wieser from the same applicant, which was submitted to the European Patent Office on the same date as the present patent application and is entitled “Schaltgerät mit Trenn-und/oder Erderfunktion” [Switching device with a disconnecting and/or grounding device function].
The described grounding device/disconnector has a particle trap, which is arranged vertically underneath the disconnector gap 4, for each of its three installation positions (see
In
A metallic wall 9, which is formed by the encapsulation 10, is formed between the particle trap 1 and the horizontally aligned isolator part 8. The particle trap 1 is located within an outward bulge 11 on the encapsulation 10. The outward bulge 11 reduces the electrical field strength in the area of the particle trap 1. The wall 9 makes it virtually impossible, or at least more difficult, for foreign body particles 2′ on the side of the wall 9 facing the particle trap 1 to move in the direction of the isolating part 8 and to reach a surface 8a of the isolating part 8 facing the interior of the grounding device/disconnector, thus resulting in the grounding device/disconnector having high operational reliability. The outward bulge 11 and the wall 9 may alternatively also be interpreted as components of the particle trap 1.
Particularly highly dielectrically loaded points in a high-voltage switching device are triple points such as the triple point 13, which is formed by the isolating part 8, the encapsulation 10 and the insulating gas 12. Foreign body particles located there are particularly dangerous to the dielectric strength of the high-voltage switching device. A wall such as the wall 9 in
In
The contact tulip 5 is used essentially as a particle trap 1′ arranged vertically underneath the two disconnecting gaps 4, 4′ in the installation position illustrated in
The particle trap 1, 1′, 1″ is advantageously arranged centrally underneath the (respective) disconnecting gap. In the case of a horizontally running disconnecting gap (as in
In the case of vertically running disconnecting gaps (
List of Reference Symbols
| Number | Date | Country | Kind |
|---|---|---|---|
| 04405115 | Feb 2004 | EP | regional |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4219366 | Dixon | Aug 1980 | A |
| 6307172 | Bolin et al. | Oct 2001 | B1 |
| 20020070199 | Ogawa et al. | Jun 2002 | A1 |
| 20020104827 | Rokunohe et al. | Aug 2002 | A1 |
| Number | Date | Country |
|---|---|---|
| 41 20 309 | Dec 1992 | DE |
| 0 776 021 | May 1997 | EP |
| Number | Date | Country | |
|---|---|---|---|
| 20050189324 A1 | Sep 2005 | US |
