DE102020203936B3 - Electrical short-circuiting device for medium and high voltage and gas-insulated switches - Google Patents

Abstract

Electrical short-circuit device for medium and high voltage with a tube, a first contact and a second contact, which are spaced apart from one another in an isolated position of the short-circuit device, a drive unit, designed, the first contact along a switching axis leading centrally through the first contact to move the second contact and thereby bring the short-circuiting device from the disconnected position into a closed position, a shielding device that at least partially radially surrounds the first contact in the disconnected position, in which the first contact has a surface area in the region of its end face facing the second contact whose distance from the switching axis is at least half as large as the distance of the shielding device from the switching axis and in which a surface of the first contact has a mean radius of curvature at at least one point which is less than 20% of the distance from the switching axis.

Description

The invention relates to an electrical short-circuit device for medium and high-voltage applications, in particular a gas-insulated short-circuit device or a short-circuit device designed as a vacuum switch, as well as a gas-insulated switch, with a tube, a first contact and a second contact, which in an isolated position of the short-circuiter Device are spaced apart from each other, a drive unit designed to move the first contact along a switching axis leading centrally through the first contact towards the second contact and thereby bring the short-circuiting device from the disconnected position into a closed position, and a shielding device that controls the radially at least partially surrounds the first contact in the disconnected position.

Switching devices are used in electrical power supply networks to separate or close electrical circuits. There are also switching devices, the main task of which is to close the contacts, for example to electrically ground a circuit to protect people. These are referred to, for example, as short circuit devices, normally open contacts or high-speed earth electrodes. These terms are used synonymously in the following. From the US 2009/0 166 168 A1 an earthing switch is known and from the DE 10 2018 216 721 A1 a circuit breaker is known.

In the open state, sufficient insulation must be ensured for normally open contacts, which is done by the geometry of the contact system with the contact distance as one of the parameters and the insulation medium. In high-voltage applications above 145 kV, switching devices with gas insulation between the contacts are preferred today, with the contact system, consisting of pin and tulip, being provided with additional screens for field control.

For the protective function of a normally open contact and to prevent damage to the switching device, it is necessary that the electrical contact is established in the shortest possible time. In high-voltage applications, the electrical contact is closed by a drive in typically> 30 ms, which is due, among other things, to the large contact spacing required due to the voltage. The increased use of power electronic equipment and the increasing demand for a reduction in internal arc performance make these short switching times appear too long in the future.

It is the object of the present invention to specify an electrical short-circuit device for medium and high voltage which enables shorter closing times.

This object is achieved by a short circuit device with the features of claim 1.

The electrical short circuit device according to the invention for medium and high voltage comprises a first contact and a second contact which are spaced apart from one another in an isolated position of the short circuit device. Furthermore, the device comprises a drive unit which is designed to move the first contact along a switching axis leading centrally through the first contact, in particular translationally towards the second contact and thereby to bring the short-circuiting device from the disconnected position into a closed position. The short-circuiting device further comprises a shielding device which at least partially radially surrounds the first contact in the disconnected position.

In the area of its end face facing the second contact, the first contact has a surface area whose distance from the switching axis is at least half as large as the distance between the shielding device and the switching axis and in which the surface of the first contact has a mean radius of curvature at at least one point that is less than 20% of the distance from the switching axis. The mean radius of curvature is understood to mean the inverse of the mean curvature, which is known to be the arithmetic mean of the main curvatures.

The switching axis runs centrally through the first contact in the direction of movement. In the case of a cylindrical or rotationally symmetrical, ie cylinder-symmetrical contact, the switching axis corresponds to the cylinder axis. In other forms, the switching axis is parallel to the direction of movement of the first contact and comprises the geometric center of gravity or the center of mass of the first contact.

The short-circuit device, that is to say the quick-release earth conductor, can be a gas-insulated switch or a vacuum switch. If the contacts are a pin-tulip system, the first contact can be a pin or a tulip, but preferably the pin, i.e. the contact that is surrounded by the other contact in the closed position. It is possible that the second contact is also moved when changing from the disconnected position to the closed position and vice versa.

The shielding device for the first contact expediently has a recess in which the first contact is arranged in the disconnected position. the The recess expediently surrounds the first contact closely in order to enable the most effective field control possible, ie to prevent excessive field increases which would increase the contact spacing in the disconnected position.

The first contact, that is to say the moving contact, of a short-circuiting device designed in this way advantageously has a surface area whose curvature is significantly higher than that of the rest of the surface and thus generates an arc very quickly when the first contact is moved.

At the same time, however, this surface area is arranged so far on the outside that its field effect is sufficiently suppressed in the separated position from the shielding device. This avoids having to significantly increase the contact spacing compared to a short-circuit device known from the prior art.

If the fast earth conductor is to make the electrical contact, the first contact is set in motion by the drive unit. The surface area of the first contact, which lies in the area of that end face which faces the second contact, thereby moves almost immediately out of the effective area of the shielding device. The geometry of the surface area, which has a location with a significantly increased curvature, causes a high field strength after leaving the shielding effect, which leads to the creation of an arc after a short distance of the first contact. As soon as an arc is present, an initial grounding is carried out.

For the invention it was recognized that a significantly increased curvature can be arranged in an area close to the shielding device without having to significantly increase the contact distance, since the shielding device weakens the increase in the electric field caused by the curvature. As soon as the first surface area leaves the effective area of the shielding device during the closing process, the increase in the electric field caused by the curvature becomes effective and promotes the creation of an arc to the second contact. The arc is created significantly earlier than with a conventional low-curvature contact shape, although with such known contact shapes the contact center in the disconnected position can even be closer to the second contact than the surface area in the short-circuiting device according to the invention.

The invention thus provides a short-circuiting device with which a live isolating section can be closed more quickly and / or with as little energy as possible, first electrically and finally galvanically.

• - Der erste Kontakt kann eine zylinderförmige oder rotationssymmetrische, auch mehrzählig rotationssymmetrische Hüllfläche haben. Beispielsweise kann der erste Kontakt ein Vollzylinder sein, insbesondere mit abgerundeten Endflächen. Der erste Kontakt kann aber auch ein Zylinder mit Bohrung entlang der Schaltachse sein, d.h. rohrförmig.
• - Der Oberflächenbereich ist zweckmäßig in der Trennstellung so nahe an der Schirmeinrichtung angeordnet, dass die Entstehung eines Lichtbogens unterbleibt, und weiterhin in der Trennstellung so nahe am zweiten Kontakt angeordnet, dass bei einem Schließvorgang des Schalters ein Lichtbogen zum zweiten Kontakt im ersten Oberflächenbereich entsteht.
• - Der Abstand des Oberflächenbereichs von der Schaltachse beträgt insbesondere wenigstens 80%, insbesondere wenigstens 90%, in einer besonderen Ausgestaltung wenigstens 95% des Abstands der Schirmeinrichtung von der Schaltachse. Dabei bezeichnet der Abstand des Oberflächenbereichs die kürzeste Entfernung von einem beliebigen der Punkte des Oberflächenbereichs zu der Schaltachse.
• - Es ist möglich, dass der gesamte Oberflächenbereich eine mittlere Krümmung wie angegeben aufweist, d.h. an jedem seiner Punkte.
• - Der erste Kontakt kann eine durchgängige zentrale Öffnung aufweisen, insbesondere bei einem gasisolierten Schalter. Mit anderen Worten kann der erste Kontakt als durchgängig offenes Rohr aufgebaut sein. Das ermöglicht vorteilhaft das Durchleiten eines Gases, das zum Löschen eines Lichtbogens bei einem Abschaltvorgang dient.
• - Die Kurzschließer-Einrichtung kann so gestaltet sein, dass bei einem Schließvorgang der Oberflächenbereich der erste Bereich des Stifts ist, der dem zweiten Kontakt näher kommt als die Schirmeinrichtung. Mit anderen Worten ist dann der Oberflächenbereich der höchste Punkt des ersten Kontakts, also der dem zweiten Kontakt in Trennstellung nächstgelegene.
• - Der Oberflächenbereich kann in Trennstellung dem zweiten Kontakt näher liegen als die Schirmeinrichtung. Anders formuliert kann der Oberflächenbereich in Trennstellung bereits leicht über die Schirmeinrichtung in Richtung zum zweiten Kontakt herausragen. Solange ein Lichtbogen in Trennstellung noch vermieden wird, wird dadurch eine weitere Verkürzung der Schließzeit erreicht. Beispielsweise kann der Oberflächenbereich um wenigstens 0,5 mm näher liegen, insbesondere um wenigstens 3 mm.
• - Der Oberflächenbereich kann alternativ gegenüber einer dem zweiten Kontakt nächstliegenden Oberfläche der Schirmeinrichtung zurückgesetzt sein, sodass er um eine Strecke weiter entfernt von einer nächstliegenden Stelle des zweiten Kontakts liegt als der Stiftschirm, deren Länge dem Reziprokwert der kleinsten mittleren Krümmung im Oberflächenbereich entspricht. Da dadurch die Schirmwirkung der Schirmeinrichtung auf den Oberflächenbereich besonders intensiv ist, wird eine starke Krümmung im Oberflächenbereich ermöglicht, die wiederum besonders schnell nach Passieren der Schirmeinrichtung beim Schließen einen Lichtbogen bewirkt. Beispielsweise kann der Oberflächenbereich um wenigstens 2 mm zurückgesetzt sein, insbesondere um wenigstens 5 mm.
• - Der Oberflächenbereich kann eine Fläche aufweisen, die wenigstens 1 % und höchstens 40 % der Deckelfläche des ersten Kontakts beträgt. Mit anderen Worten handelt es sich bei dem Oberflächenbereich nicht um die gesamte Deckelfläche, aber auch nicht um eine Oberflächenunreinheit. Als Deckelfläche wird bevorzugt π*r² angenommen, wobei r der Radius des ersten Kontakts ist, auch wenn die tatsächliche Deckelfläche nicht einer Zylinder-Deckelfläche entspricht. In einer besondere Ausgestaltung kann der Oberflächenbereich ringförmig sein. In weiteren Ausgestaltungen kann der Oberflächenbereich zwischen 5 % und 25 % der Deckfläche des ersten Kontakts betragen. Als Deckelfläche kann auch diejenige Fläche angesehen werden, die von dem äußeren Rand des ersten Kontakts umschlossen wird. Damit ergibt sich insbesondere für einen Vollzylinder und ein Rohr desselben Durchmessers dieselbe Deckelfläche.
• - Der erste Kontakt kann im Bereich seines dem zweiten Kontakt zugewandten Endes einen oder mehrere konkave oder sattelförmige Oberflächenabschnitte aufweisen.
• - Der mittlere Krümmungsradius kann höchstens 15% des Abstands von der Schaltachse betragen, insbesondere höchstens 12%. In weiteren Ausgestaltungen kann der mittlere Krümmungsradius höchstens 10% oder höchstens 5% des Abstands der Schirmeinrichtung von der Schaltachse betragen.
• - Der Oberflächenbereich kann zylindersymmetrisch geformt sein. Beispielsweise kann der Oberflächenbereich den äußeren Kontaktrand umlaufen und darin ein Grat gebildet sein.
• - Alternativ kann der Oberflächenbereich unzusammenhängend sein und der erste Kontakt mehrzählig rotationssymmetrisch. Beispielsweise können Bereiche erhöhter Krümmung als zahnartige Vorsprünge auf der Deckelfläche des ersten Kontakts aufgebaut sein. Dadurch ist der erste Kontakt nicht mehr vollständig rotationssymmetrisch, sondern stattdessen mehrzählig, beispielsweise zwölfzählig oder 20-zählig.
• - Der mittlere Krümmungsradius kann in einer Ausgestaltung höchstens 3 mm betragen, insbesondere höchstens 1 mm, insbesondere höchstens 0,5 mm.
• - Die Oberflächenkontur eines Querschnitts durch den ersten Kontakt kann im Oberflächenbereich einen Wendepunkt aufweisen.

Advantageous refinements of the short-circuiting device according to the invention emerge from the claims dependent on claim 1. The embodiment according to claim 1 can be combined with the features of one of the subclaims or preferably also with those from several subclaims. Accordingly, the following features can also be provided for the short-circuiting device:

• The first contact can have a cylindrical or rotationally symmetrical, also multiple rotationally symmetrical envelope surface. For example, the first contact can be a solid cylinder, in particular with rounded end surfaces. The first contact can, however, also be a cylinder with a bore along the switching axis, ie tubular.
• - The surface area is expediently arranged so close to the shielding device in the disconnected position that the creation of an arc does not occur, and furthermore in the disconnected position so close to the second contact that when the switch is closed, an arc is created to the second contact in the first surface region.
• The distance of the surface area from the switching axis is in particular at least 80%, in particular at least 90%, in a special embodiment at least 95% of the distance between the shielding device and the switching axis. The distance of the surface area denotes the shortest distance from any one of the points of the surface area to the switching axis.
• It is possible that the entire surface area has an average curvature as indicated, ie at each of its points.
• The first contact can have a continuous central opening, in particular in the case of a gas-insulated switch. In other words, the first contact can be constructed as a continuously open tube. This advantageously enables a gas to be passed through, which is used to extinguish an arc during a shutdown process.
• The short-circuiting device can be designed in such a way that, during a closing process, the surface area is the first area of the pin which comes closer to the second contact than the shielding device. In other words, the surface area is then the highest point of the first contact, that is to say the one closest to the second contact in the separated position.
• - The surface area can be closer to the second contact in the disconnected position than the shielding device. In other words, the surface area can be in the separated position already protrude slightly over the shielding device in the direction of the second contact. As long as an arc is still avoided in the disconnected position, a further shortening of the closing time is achieved. For example, the surface area can be closer by at least 0.5 mm, in particular by at least 3 mm.
• The surface area can alternatively be set back from a surface of the shielding device closest to the second contact, so that it lies a distance further away from a closest point of the second contact than the pen shield, the length of which corresponds to the reciprocal value of the smallest mean curvature in the surface area. Since the shielding effect of the shielding device on the surface area is particularly intense as a result, a strong curvature is made possible in the surface area, which in turn causes an arc to be formed particularly quickly after passing the shielding device when it closes. For example, the surface area can be set back by at least 2 mm, in particular by at least 5 mm.
• The surface area can have an area which is at least 1% and at most 40% of the cover area of the first contact. In other words, the surface area is not the entire cover surface, but neither is it a surface impurity. The cover area is preferably ^{assumed to be π * r 2} , where r is the radius of the first contact, even if the actual cover area does not correspond to a cylinder cover area. In a particular embodiment, the surface area can be ring-shaped. In further refinements, the surface area can be between 5% and 25% of the top surface of the first contact. The surface that is enclosed by the outer edge of the first contact can also be regarded as the cover surface. This results in the same cover surface, in particular for a full cylinder and a tube of the same diameter.
• The first contact can have one or more concave or saddle-shaped surface sections in the region of its end facing the second contact.
• The mean radius of curvature can be a maximum of 15% of the distance from the switching axis, in particular a maximum of 12%. In further refinements, the mean radius of curvature can be at most 10% or at most 5% of the distance between the shielding device and the switching axis.
• - The surface area can be shaped cylindrically symmetrical. For example, the surface area can run around the outer contact edge and a ridge can be formed therein.
• - Alternatively, the surface area can be incoherent and the first contact can be rotationally symmetrical in multiple ways. For example, areas of increased curvature can be built up as tooth-like projections on the cover surface of the first contact. As a result, the first contact is no longer completely rotationally symmetrical, but instead has multiple numbers, for example twelve or twenty.
• In one embodiment, the mean radius of curvature can be a maximum of 3 mm, in particular a maximum of 1 mm, in particular a maximum of 0.5 mm.
• The surface contour of a cross section through the first contact can have a point of inflection in the surface area.

The invention is described and explained in more detail below using the exemplary embodiments shown in the figures.

• 1 ein Tulpe-Stift-Kontaktsystem,
• 2 bis 6 räumliche Ansichten und Schnittbilder von weiteren Ausführungen für den Stift des Tulpe-Stift-Kontaktsystems.

They show schematically:

• 1 a tulip-pin contact system,
• 2 until 6th spatial views and sectional views of further designs for the pen of the tulip-pen contact system.

1 shows a cross section through a tulip-pin contact system 10 , which is arranged in an insulating gas atmosphere and forms part of a rapid earthing element according to an embodiment for the invention.

The quick earth electrode includes a tulip 12th , a pen screen 14th and a pen 16 . All three elements are designed in their central area, which is used for electrical contact, essentially rotationally symmetrical, that is, cylindrically symmetrical. The pen screen 14th surrounds the pen 16 radially in its rest position, ie in the separated position of the high-speed earthing device.

The pencil 16 is essentially cylindrical and arranged to be movable along the cylinder axis. For moving to the tulip 12th there is a drive. The tulip 12th has an open central area 18th on where the pen 16 can be immersed in order to establish a galvanic contact. Around this central area 18th around the tulip has a tulip umbrella 20th on. Tulip umbrella 20th and pen screen 14th are used for field control and prevent the occurrence of discharges, e.g. corona discharges or an unwanted electric arc, when the high-speed earth electrode is in the disconnected position. This can reduce the contact spacing 26th be kept lower.

In 1 is still the direction of movement 22nd of the pin when closing, i.e. when establishing an earthing and the closed position 24 of the pen indicated after the closing process. In the closed position 24 stands the pen 16 in mechanical contact with the tulip 12th and thereby establishes the final electrical contact.

In order to achieve a short switching time, sufficient drive energy must be available. This increases linearly with the contact mass and quadratically with the speed. The contact distance is related to the speed 26th Thus, with a given switching time and drive energy, there is a disproportionate influence on the switching time. The contact spacing 26th in turn, increases with the system voltage. To the contact distance 26th The contacts are to be kept as low as possible at a given voltage 12th , 16 and the shields 14th , 20th usually shaped so that the surface field strength remains as low as possible.

On the other hand, the pen points 16 distinctive curves or curves, which leads to the emergence of the pen 16 from the shielding at as great a distance as possible from the tulip 12th a switching arc already occurs, which leads to electrical contact and thus to the desired earthing.

A first example of such a geometry of the pin 16 is spatially in 2 shown. A cross section of the pen 16 show the 3 . The pencil 16 the 2 and 3 is shaped like a cylinder. The end face of the cylinder pointing upward in the figures points in the direction of the tulip 12th . It has a slight elevation in its center, so it is convex, but with only a slight curvature.

Towards the outer edge of the end face, the curvature reverses several times and forms in a circumferential surface area 25th a circumferential ridge 28 the end. The pencil 16 this embodiment is therefore at least in the area of its to the tulip 12th facing end face rotationally symmetrical with respect to the pin axis, which at the same time corresponds to the in 1 Direction of movement of the pen shown 16 is, i.e. the switching axis A. .

The ridge 28 points in the radial direction shown in 3 shown has a significantly higher curvature than the remainder of the end face of the pin 16 . As a result, the electric field strength is significantly higher in its area than in the slightly curved central area of the end face of the pin 16 . Since the ridge 28 near the outside edge of the pen 16 , so close to the pen screen 14th its effect, however, prevents large discharges or an electric arc from occurring even in the disconnected position of the high-speed earth electrode, ie the effect of the pen screen 14th prevents through the ridge 28 requires a significantly larger contact distance 26th is necessary. The top of the ridge 28 is at the same height as the pen screen in this example 14th , thus has the same orthogonal distance to the tulip 12th on.

In alternative configurations, depending on the design of the high-speed earth electrode, the upper edge of the ridge 28 in the separated position by a distance from the pen screen 14th be raised, that is, closer to the tulip 12th or some distance from the pen screen 14th be lowered, ie further from the tulip 12th be distant. Such configurations are used to optimally match the insulation effect and the rapid establishment of electrical contact.

If a closing process of the quick earthing is initiated, then the pin 16 to the tulip 12th accelerated towards. Since the ridge 28 near the outside edge of the pen 16 is arranged, is its distance from the pen screen 14th small amount. As the distance from a point on the ridge 28 from the pen screen 14th becomes the shortest distance from the point to any point on the pen screen 14th considered. Since this distance is small, the movement to the tulip increases 12th which is roughly perpendicular to the respective shortest distance between the ridge 28 and pen screen 14th takes place the distance very quickly. This reduces the shielding effect of the pen shield 14th fast and the strong field effect of the ridge 28 very quickly leads to the creation of a discharge or an electric arc, which begins in the area of the burr 28 takes.

So it is used that a surface area with strong curvature like the ridge 28 who is very close to the pen screen 14th is arranged, can reach a full field effect in a very short distance from sufficient shielding.

Two further embodiments for pens 16 show the 4th and 5 . In these exemplary embodiments there is no continuous ridge 28 shaped. Instead, according to the example 4th the pencil 16 twelve tooth-like protrusions 41 on its outer edge. This is the pen 16 according to 4th not completely rotationally symmetrical like that of the 2 , but twelve-fold rotationally symmetrical. The protrusions 41 have radial and azimuthal points of high curvature, but these are analogous to the ridge 28 near the pen screen 14th and are thereby limited in their field effect in the separated position. In a cross section through the pen 16 , the one of the protrusions 41 includes, there are one or more inflection points in the surface contour.

The pencil 16 according to 5 has a plurality of protrusions 51 on that in contrast to the protrusions 41 according to 4th are less angular in shape, but are arranged in an analogous manner and have analogous properties.

In all three exemplary embodiments according to 2 , 4th and 5 is the inner area of the top surface of the pen 16 convex shaped and gentle to the tulip 12th arched down. Alternatively, it is also possible to use the top surface of the pen 16 concave shape and a bulge from the tulip 12th to shape away.

Another embodiment shows 6th . 6th represents a cross-section through the pen 16 represents. The pen 16 according to 6th is tubular. At the tulip 12th facing end of the tube is analogous to the 2 and 3 a circumferential ridge 28 arranged. Alternatively, protrusions can also be used 41 , 51 be arranged there. The advantage of using a tubular pin 16 is a reduced mass of the pen 16 , which is easier to accelerate for a closing process. Furthermore, the pen 16 be designed as a continuously open tube. This makes it possible for a separation process in which the high-speed earth electrode again interrupts the electrical contact to introduce a gas through the pin, which supports the extinguishing of an arc and thus the separation process.

List of reference symbols

10

Tulip pin contact system

12th

tulip

14th

Pen screen

16

pen

18th

Recess

20th

Tulip umbrella

22nd

Direction of movement

24

Closed position

25th

Surface area

26th

Contact spacing

WP

Turning point

28

ridge

41, 51

Ledges

r

radius

A.

Switching axis

Claims (14)

Electrical short-circuit device for medium and high voltage with - a tube with a first contact (16) and a second contact (12), which are spaced apart from one another in an isolated position of the short-circuit device, - a drive unit, designed, the first contact (16 ) to move along a switching axis (A) leading centrally through the first contact (16) to the second contact (12) and thereby bring the short-circuiting device from the disconnected position into a closed position, - a shielding device (14), which the first Radially at least partially surrounds the contact (16) in the disconnected position, characterized in that the first contact (16) has a surface area (25) in the region of its end face facing the second contact (12), at least its distance from the switching axis (A) is half as large as the distance of the shielding device (14) from the switching axis (A), - in which one surface of the first contact (16) at at least one point has an average radius of curvature which is less than 20% of the distance from the switching axis (A). Electrical short-circuit device according to Claim 1 , in which the surface area (25) - is arranged so close to the shielding device (14) in the separated position that the formation of strong discharges does not occur, and - in the separated position is arranged so close to the second contact (12) that with a Closing process of the short-circuiting device an arc to the second contact (12) in the first surface area (25) is created. Electrical short-circuit device according to Claim 1 or 2 , in which the first contact (16) has a continuous central opening. Electrical short-circuiting device according to one of the preceding claims, in which, during a closing process, the surface area (25) is the first area of the first contact (16) which comes closer to the second contact (12) than the shielding device (14). Electrical short-circuiting device according to one of the preceding claims, in which the surface area (25) in the disconnected position is closer to the second contact (12) than the shielding device (14), in particular by at least 0.5 mm. Electrical short-circuiting device according to one of the Claims 1 until 4th , in which the surface area (25) is set back with respect to a surface of the shielding device (14) closest to the second contact (12), so that it is a distance further away from a closest point of the second contact (12) than the shielding device (14) whose length corresponds to the reciprocal of the smallest mean curvature in the surface area (25), in particular at least 0.5 mm. Electrical short-circuiting device according to one of the preceding claims, in which the surface area (25) has an area which is at least 1% and at most 40% of the cover area of the first contact (16), in particular between 5% and 25%. Electrical short-circuiting device according to one of the preceding claims, in which the first contact (16) has one or more concave surface sections in the region of its end facing the second contact (12). Electrical short-circuiting device according to one of the preceding claims, in which the mean radius of curvature is at most 15% of the distance from the switching axis (A), in particular at most 12%. Electrical short-circuiting device according to one of the preceding claims, in which the distance of the surface area (25) from the shielding device (14) is at most 50%, in particular at most 30%, in a particular embodiment at most 10% of the distance between the shielding device (14) and the Switching axis (A). Electrical short-circuiting device according to one of the preceding claims, in which the first contact (16) is shaped to be rotationally symmetrical. Electrical short-circuiting device according to one of the Claims 1 until 10 , in which the surface area (25) is incoherent and the first contact (16) is multiple rotationally symmetrical. Electrical short-circuiting device according to one of the preceding claims, in which the mean radius of curvature is at most 3 mm, in particular at most 0.5 mm. Gas-insulated switch, which comprises at least one electrical short-circuit device according to one of the preceding claims.

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