EP2087498B1 - High-voltage circuit breaker comprising a rotary arc - Google Patents

Abstract

The invention relates to a high-voltage circuit breaker comprising a housing (10) filled with insulating gas and a heat space (14) for receiving compressed quenching gas. When a current (I) with a small, average or high intensity is interrupted, the quenching gas is heated and pressurised by a rotary arc (S) which is exposed to a current-dependent magnetic flux density (B). Two contact pieces (20, 30) that can be moved in relation to each other along an axis (A) are arranged in the housing (10), one (30) of said contact pieces comprising a coaxial arrangement of an arcing contact (31), an arcing ring (15), and a coil (C) surrounding the arcing contact (31). Said coil (C) is electroconductively connected to the arcing ring (15) and leads to the current (I) to be interrupted. The coil (C) comprises two windings (40, 50) wound in opposite directions. Said windings are embodied and arranged in such a way that, when a current with a high intensity is interrupted, the component of the magnetic flux density (B), contributing to the rotation of the arc (S), is smaller on the arcing ring than in a switch which is identical but comprises a coil (C) which is wound in the same direction. The heat space (14) can therefore be small, enabling a compact switch.

Description

TECHNICAL AREA

The present invention relates to a high voltage circuit breaker according to the preamble of claim 1.

In a switch of the aforementioned type, the energy of a switching arc rotating in a magnetic field is utilized in order to generate an extinguishing gas provided for blowing the switching arc. The switching arc rotates in a housing which is filled with an insulating gas with a pressure of up to a few bar. The quenching gas is stored in a heating volume, which is connected via a generally annular channel with an arc zone receiving the switching arc.

STATE OF THE ART

A switch of the type mentioned is described in EP 0 731 482 A2 , This switch has a power-current path arranged in an insulating gas-filled housing with two contact pieces displaceable relative to one another along an axis, one of which has an arc contact, an arc runner ring and a cylindrical coil surrounding the arc contact in coaxial arrangement. Through this coil flows when turned off the current to be disconnected. The magnetic field of this current acts on a switching arc which opens on the arc running ring when the power current path is opened. Under the influence of electrodynamic forces now held on the raceway switching arc rotates about the axis and heats the insulating gas. In this case formed compressed gas is passed from the arc of arc receiving receiving arc zone in a heating volume. As the current to be disconnected approaches a zero crossing, the compressed gas then flows from the heating volume into the arc zone and inflates the switching arc until the current to be disconnected is interrupted.

When switching off large currents and with long arc times so much highly compressed, hot compressed gas is formed. Since this gas is fed into the heating volume, this must be comparatively large and robust, although actually for the successful blowing of the switching arc so much extinguishing gas is needed. Therefore, in this switch, the coil is at least partially short-circuited. When switching large currents, the size of the magnetic field is then reduced by partial or complete short-circuiting of the coil, so that the formation of compressed gas is possibly drastically reduced. The volume of the heating volume can be kept low in manufacturing technology advantageous manner.

Another switch, in which the rotation of the switching arc in the magnetic field of a current flowing through the current to be interrupted coil arrangement is used to interrupt a current, is in FR 2 418 962 A described. The coil arrangement has two coils arranged on a common axis with windings wound in opposite directions.

PRESENTATION OF THE INVENTION

The invention, as indicated in the claims, has the object to simplify the switch of the type mentioned.

In the switch according to the invention, the coil has two oppositely wound windings, which are concentrically arranged to form an inner and an outer winding, and is provided in coaxial arrangement between the arcing contact and the inner winding, a ferromagnetic first sleeve. As a result, when a small current is interrupted, the magnetic flux density at the location of the arc runner is effectively increased. This is due to the fact that the ferromagnetic sleeve is then not yet magnetically saturated by the magnetic field of the coil carrying the small current. The magnetic flux density at the location of the arc runner and thus also the electromagnetic force on the switching arc therefore increase proportionally with the current, so that the pressure of the extinguishing gas increases in proportion to the strength of the small current to be interrupted. When switching a large current is the ferromagnetic sleeve, however, saturated magnetically. The magnetic flux density at the location of the arc runner grows then more slowly with increasing current than when breaking a small current, since with saturated ferromagnetic core, the magnetic flux density now evenly distributed on all materials, regardless of whether Ferromagnetikum, conductor material or ambient air. At the same time, the magnetic field of the outer winding influences the oppositely directed field of the inner winding more than before when interrupting a small current. At the location of the arc runner, the direction of the magnetic flux density changes and thereby decreases the angle between the magnetic flux density and the direction of the current conducted in the switching arc. On the switching arc then acts a lower electrodynamic force than in a switch according to the prior art, which is identical except for the structure of the coil, but in which the coil has no oppositely wound windings. When interrupting large currents therefore an extinguishing gas is developed with a lower pressure than the comparable switch according to the prior art.

Since an oppositely wound coils having coil can be easily produced, the heating volume can be kept small using simple means and accordingly designed the switch to save space and manufactured inexpensively.

In an embodiment of the switch according to the invention designed as a generator switch, an up to 20% higher magnetic field can be achieved at the location of the arc running ring when interrupting smaller, typically 5 to 25 kA currents than with a comparably dimensioned switch, but without a counterwinding. Accordingly, when switching large currents, typically 150 to 300 kA, the magnetic field is reduced by up to 40% compared with the comparison switch according to the prior art, while when switching medium currents, typically 50 to 100 kA, only insignificantly State of the art changes.

So that the coil with a simple structure can absorb the considerable mechanical forces occurring when switching large currents, the Inner winding have a greater number of turns than the outer winding. In addition, it is recommended that for reasons of ease of manufacture and a high mechanical strength of the arc runner end faces of the inner and outer windings electrically conductively connected to each other via a current conductor, the arc runner facing end faces of the inner and outer winding each in the manner of a ring form and connect the power connector of the inner winding in an electrically conductive manner with the arc runner.

The aforementioned conductor is advantageously designed in the manner of a ring. Facing away from the arc ring end faces of the inner and outer winding can then be supported on the ring and held with simple fasteners.

A particularly stable coil is achieved with little effort when the conductor is formed in the outer winding and formed in the manner of a ring, and when a side facing away from the arc running end face of the inner winding is supported on the ring.

An increase in the magnetic flux density at the location of the arc runner and a particularly good stability of the coil is achieved when a further ferromagnetic sleeve is provided in coaxial arrangement between the inner and the outer winding.

Since eddy currents reduce the magnetic flux density of the coil at the location of the arcing contact, at least one predominantly axially and radially guided slot is arranged at least in the first or the second sleeve or in the ring-shaped current connection of the inner winding or the outer winding. In the first and / or second sleeve advantageously at least two uniformly distributed in the direction of access slots are arranged. In order to be able to absorb large current forces, generally only a first slot is formed in the power connection of the outer winding, and generally only a second slot is formed in the current connection of the inner winding. These two slots are in the axial direction at most up to a subsequent to the power connection of the inner and the outer winding winding of the inner and the Outside winding out. In embodiments of the switch, which are characterized in particular by certain numbers of turns of the outer and inner windings, it is advantageous to form the coil so that the first and the second slot are radially extending in the same direction.

A Wirbelstromunterdrückender third slot is formed with advantage in the inner and the outer winding electrically conductively interconnecting conductor. Depending on the design of the coil by the number of turns of the inner and the outer winding, the first, the second and the third slot may extend radially in the same direction or at least two of the three slots may extend radially in different directions.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig.1

eine Aufsicht auf einen längs einer Achse A geführten Schnitt durch eine erste Ausführungsform eines Hochspannungsleistungsschalter nach der Erfindung, bei der der Schalter links der Achse im Einschaltzustand und rechts der Achse beim Ausschalten dargestellt ist,

Fig.2

ein Diagramm, in dem die beim Ausschalten des Schalters nach Fig.1 sowie eines Schalters nach dem Stand der Technik jeweils in einer Schalterspule erzeugte und zur Rotation eines Schaltlichtbogens beitragende magnetische Flussdichte B [T] in Funktion der Stärke des abzuschaltenden Strom I [kA] dargestellt ist,

Fig.3

ein Schaltstück einer zweiten Ausführungsform des Hochspannungsleistungsschalter nach der Erfindung, welches in der rechten Hälfte längs der Achse A geschnitten dargestellt ist,

Fig.4

eine von unten geführte in Richtung von Pfeilen IV geführte Ansicht des Schaltstücks gemäss Fig.3, bei der zentral angeordnete sowie als Isolierung ausgeführte Teile nicht dargestellt sind, und

Fig.5

eine entsprechend Fig. 4 geführte Ansicht eines Schaltstücks einer dritten Ausführungsform des Hochspannungsschalters nach der Erfindung, welche gegenüber der Ausführungsform nach Fig.4 geringfügig abgewandelt ist.

With reference to drawings, embodiments of the invention will be explained in more detail below. This shows

Fig.1

a plan view of a guided along an axis A section through a first embodiment of a high-voltage circuit breaker according to the invention, in which the switch is shown on the left of the axis in the on and right of the axis when switched off,

Fig.2

a diagram in which the after switching off the switch after Fig.1 and a switch according to the prior art in each case in a switch coil generated and contributing to the rotation of a switching arc magnetic flux density B [T] in function of the strength of the current I to be disconnected [kA] is shown,

Figure 3

a switching piece of a second embodiment of the high-voltage circuit breaker according to the invention, which is shown cut in the right half along the axis A,

Figure 4

a guided from below in the direction of arrows IV view of the switching piece according Figure 3 , are not shown in the centrally arranged and designed as insulation parts, and

Figure 5

one accordingly Fig. 4 Guided view of a contact piece of a third embodiment of the high voltage switch according to the invention, which compared to the embodiment according to Figure 4 is slightly modified.

WAYS FOR CARRYING OUT THE INVENTION

In all figures, like reference numerals refer to like-acting parts. The in Fig.1 shown circuit breaker is a generator switch and can turn off at high voltages up to 100 kV currents up to a still permissible maximum short-circuit breaking current of typically 300 kA. It contains a filled with a compressed insulating gas, such as based on sulfur hexafluoride, nitrogen or carbon dioxide or a gas mixture based on one or more of these gases, housing 10 and received by the housing 10 and largely axially symmetrical contact arrangement with two along an axis A relative In the on state, the two switching pieces 20 and 30 are not shown rated current contacts in a schematically indicated, low-resistance Nennstrompfad N and with an arcing contact 21 and an arc contact 31, a ferromagnetic sleeve 32 and a cylindrical coil C in one dashed lines shown power current path L, which is guided parallel to the rated current path.

The apparent tubular, but optionally also massively configured, arc contact 21 is guided by an insulating tube 11 acting as an auxiliary nozzle and contacted in the on state of the switch (left half of Fig.1 ) the contact finger having arc contact 31. The insulating tube 11 and an am Switching piece 30 held insulating 12 limit an annular heating channel 13, which when switched off (right half of Fig.1 ) connects an arc zone, which receives a switching arc S, with a heating volume 14.

The switching piece 30 is fixedly held in the housing 10 and formed largely in the manner of a hollow cylinder. The switching piece 30 includes in coaxial arrangement from the inside to the outside, the tubular, designed in the manner of a tulip arcing contact 31, the sleeve 32, a two-winding inner winding 40 of the coil C, another ferromagnetic sleeve 33 and in the opposite direction to the inner winding 40 wound and only a winding having outer winding 50 of the coil C. At its the contact piece 20 facing end face, the contact piece 30 an arc runner 15 made of a erosion resistant material, in particular graphite, a retaining ring 16 for fixing the arc runner 15 on an end face of the inner winding 40 and the insulating 12, which is seated on end faces of the retaining ring 16, the sleeve 33 and the outer winding 50 and the arc running ring 15 radially outwardly limited.

On end faces of the inner 40 and the outer winding 50, which are remote from the arc running ring sits, designed as a ring plate conductor 52, which connects the inner and the outer winding electrically conductive together. The arc faces of the ring 15 facing end surfaces of the inner 40 and the outer winding 50 each have a designed in the manner of a ring power connection 41 and 51, respectively. The power connector 41 is electrically connected to the arc runner 15. The power connection 51 serves as a power connection of the switching piece arrangement and sets the switching piece 30 on the housing 10. The two turns of the inner winding 40 are designated by the reference numeral 43, whereas the single turn of the outer winding 50 is designated by the reference numeral 54.

In the ferromagnetic sleeve 32 and 33 axially aligned slots 321 and 331 are formed. As explained later, these slots serve as well as in the windings 40, 50 molded - only from the FIGS. 3 to 5 apparent - slits 42, 53, 55 of the suppression of eddy currents.

The individual parts of the contact piece 30 are generally connected by screws. The sleeve 32 is seated with its downwardly facing end face on a flange 311 of the tulip-shaped arc contact 31 and is screwed to this flange. Alternatively, both parts can be connected to each other by press fit. The generally aluminum or copper resp. an aluminum or copper alloy existing windings 40, 50 as well as the ferromagnetic sleeve 33 are screwed to the running as a ring plate conductor 52. The arc runner 15 is fixed electrically conductive by means of the metal retaining ring 16 at the power connector 41 of the inner winding 40. The power connector 41 and thus also the coil C are fixed by means of screws or press fit on the upper end side of the sleeve 32. Cavities provided between the individual parts, such as insulating distances between the turns 43, 54 and the current terminals 41, 51 of the coil C, between the windings 40, 50 of the coil, the ferromagnetic sleeves 32, 33 and the arcing contact 31 or like the slots 42, 53, 55, are filled with insulating material. This material is in Fig.1 not shown.

In the on state (left half of Fig.1 ), the nominal current path N and the power current path L are closed and the switch carries current, which flows predominantly in the rated current path and only with a share of about 1% in the power current path. To turn off the switching piece 20 is guided by a drive, not shown upwards. The rated current path N opens first. The current to be disconnected now commutes completely into the power current path L and flows from the arcing contact 21 via the arcing contact 31, the ferromagnetic sleeve 32, the inner winding 40, the current conductor 52 and the outer winding 50 wound in the opposite direction to the inner winding to the power connection 51st

In the course of the switching off the guided with friction in the arcing contact 31 arc contact 21 is disengaged from the fixed contact 30 and then forms between the arcing contact 21 and contact fingers of the arcing contact 31, a switching arc S, which commutes to the arc runner 15 (right half of Fig.1 ). The commutation is rapid, since the sleeve 32 and the Arcing contact 31 in this case be taken from the power current path L and the current to be disconnected now flows from the arcing contact 21 via the switching arc S, the arc runner 31, the inner winding 40, the current conductor 52 and the opposite direction to the inner winding wound outer winding 50 to the power connector 51.

In arc S, the current I to be disconnected flows essentially in the axial direction. When switching off small or medium currents (up to about 10% or between about 10 and about 30% of the maximum permissible short-circuit breaking current), the magnetic flux density B caused by the coil C and the ferromagnetic sleeves 32 and 33 is in the range of Arc run 15 mainly aligned radially. Therefore acting on the arc running at the arc running ring 15 switching arc S has a circumferentially acting electrodynamic force, causes a rotation of the arc about the axis A and the pressure gas required for arc extinction is generated. As the current of the current to be switched off increases, the magnetic field of the outer winding 50 influences the oppositely directed field of the inner winding 40 more than before with smaller currents. At the location of the arc runner 15, the direction and magnitude of the magnetic flux density B change, respectively. the size of a predominantly radially oriented component of B continuously. For currents with high currents (about 30 to 100% of the maximum permissible short-circuit breaking current), the size of this component is greatly reduced, so that a lower electrodynamic force acts on the switching arc S than in an identically designed switch according to the prior art with the same direction current flowing through the coil. Therefore, the B-I characteristic curve of the coil C flattens considerably more in the region of large currents than in the case of the coil of the switch of the state of the art, through which current flows in the same direction.

This fact is from the in Fig.2 shown diagram. It can be seen from this diagram that in the embodiment of the switch according to the invention according to FIG Fig.1 with a still permissible maximum short-circuit breaking current of 300 kA, above about 50 to 100 kA, ie especially at high currents, the characteristic flattened much more than the characteristic of a coil of a switch of the same design by the state The technique, however, in which the coil is wound in the same direction. The flattening of the characteristic curve shown by a downward arrow is already approximately 20% at a current intensity of 200 kA and at the maximum permissible current intensity of 300 kA already approximately 40%. Accordingly, therefore, the volume of the heating volume 14 can be reduced.

In order to optimize at low currents I contributing to the rotation of the switching arc S, mainly axially aligned component of the magnetic field of the coil, additional means in the coil C are provided by the interruption of small currents, a high magnetic flux density B at the location of the arc run 15 is reached. Such small currents generally reach about 5 to 10% of the maximum allowable Kurzschlussabschaltstroms and therefore in the embodiment according to Fig.1 about 15 to 30 kA.

These additional means relate on the one hand, the two ferromagnetic sleeves 32 and 33. By appropriate selection of the material and the geometric dimensions of these sleeves and by arranging the sleeve 32 between the arcing contact 31 and the inner winding 40, respectively. the sleeve 33 between the inner 40 and the outer winding 50, the magnetic flux density B at the location of the arc runner 15 is considerably increased. In addition, the geometric dimension, in particular the wall thickness of the sleeve 32, as large as possible and is used as the material of the sleeve is a Ferromagnetikum with a low coercive force, such as soft iron or an alloyed with silicon iron alloy. It is thus achieved at low currents already a relatively high magnetic flux density at the location of the arc runner 15.

On the other hand, the formation of eddy currents is also effectively suppressed by the means. Therefore, in each case formed as a ring power connections 41 and 51 of the inner 40 bzw.der outer winding 50 each formed at least one predominantly axially and radially guided slot. These slots are out Fig.1 not to be seen, but are in a corresponding manner in the embodiment of the inventive switch after the FIGS. 3 and 4 and in the embodiment according to Figure 5 realized there and designated by the reference numeral 42 for the power connector 41 and the reference numeral 53 for the power connector 51. These two slots are in the axial direction at most up to a to the power supply 41 and 51 of the inner 40 and the outer winding 50 subsequent turn 43 of the inner or 54 of the outer winding out. In the radial direction, they can have the same direction, but can also point radially in different directions and, for example, be opposite (FIG. Figure 5 ) can be arranged.

From the FIGS. 3 to 5 it can be seen that a vortex current suppressing slot 55 is also formed in the inner conductor and the outer winding electrically interconnecting conductor 52 is formed. The three slots 42, 53 and 55 can look like Fig. 4 it can be seen - extend radially in the same direction. Depending on the number of turns of the two windings 40, 50 and the electrodynamic forces occurring at both windings, however, at least two of the three slots may also extend radially in different directions ( Figure 5 ).

As before at Fig.1 Whirl current suppressing slots 321 and 331 may also be provided on the two ferromagnetic sleeves 32 and 33, respectively. Advantageously, at least two, typically ten to thirty, in the direction of uniformly distributed, axially aligned slots are formed in each sleeve. The slots 321 and 331 may be passed through the entire sleeve wall. They then extend in the axial direction only over part of the sleeve length. You can then apply either all on one of the two faces of the sleeve or alternately on both faces. The slots can each be formed as a groove in the inner surface and / or the outer surface of the sleeve.

From the diagram according to Fig.2 It can be seen that the component contributing to the arc rotation of the magnetic flux density B at the location of the arc runner 15 at small and partially medium currents, ie at currents up to about 70 kA, compared to an identically designed switch according to the prior art by the aforementioned means However, which has a co-current-carrying coil, increased by about 10 to 20%.

In the embodiment of the inventive switch according to the FIGS. 3 and 4 is in contrast to the embodiment according to Fig.1 between inner 40 and outer winding 50 no ferromagnetic sleeve provided. Moreover, in manufacturing technology advantageous and the mechanical strength of the coil C increasing manner of the current conductor 52 formed in the outer winding 50 and formed in the manner of a ring. The remote from the arc runner 15 end face of the inner winding 40 is supported on this ring. In contrast to the embodiment according to Fig.1 is the cavities between the individual current-carrying parts, such as the windings 40, 50, the sleeve 32 and the arcing contact 31, filling insulating material now shown and designated by the reference numeral 34. This material is preferably a cured potting material based on polyurethane or epoxy.

Instead of only two turns 43 having inner winding 40 and / or only one turn 54 having outer winding 50, the number of turns can also be larger or smaller. For example, the inner winding may have two and the outer winding one and a half turns. For switches, which are provided for interrupting comparatively low-power currents, the number of turns can also be considerably higher.

LIST OF REFERENCE NUMBERS

10

casing

11

insulating

12

insulating

13

heating duct

14

heating volume

15

Arcing ring

16

retaining ring

20

switching piece

21

Arcing contact

30

switching piece

31

Arcing contact

311

flange

32, 33

ferromagnetic sleeves

321, 331

Schlitten

34

insulating material

40

interior winding

41

power connection

42

slot

43

turns

50

Outside winding

51

power connection

52

conductor

53,55

slots

54

convolution

A

axis

B

magnetic flux density

C

Kitchen sink

I

electricity

L

Power current path

N

Current Path

S

Switching arc

Claims (14)

1. High-voltage circuit breaker having an insulating-gas-filled housing (10), a heating volume (14) for holding compressed quenching gas, which is in each case heated and compressed by a rotating switching arc (S), which is subject to a current-dependent magnetic flux density (B), when interrupting a current (I) of low, medium or high current intensity, and having two switching pieces (20, 30), which can move relative to one another along an axis (A) and are arranged in the housing (10), one (30) of which has, arranged coaxially, an arc contact (31), an arcing ring (15) and a coil (C), which surrounds the arc contact (31), is electrically conductively connected to the arcing ring (15) and carries the current (I) to be interrupted, characterized in that the coil (C) has two windings (40, 50) which are wound in opposite senses and are arranged concentrically forming an inner winding and an outer winding, and in that a ferromagnetic first sleeve (32) is provided, arranged coaxially, between the arc contact (31) and the inner winding (40).
2. Circuit breaker according to Claim 1, characterized in that the inner winding (40) has a greater number of turns (42) than the outer winding (50).
3. Circuit breaker according to one of Claims 1 or 2, characterized in that end faces of the inner winding (40) and of the outer winding (50) which are averted from the arcing ring (15) are electrically conductively connected to one another via an electrical conductor (52), in that end surfaces of the inner winding (40) and of the outer winding (50) which face the arcing ring (15) each have an electrical connection (41, 51) which is in the form of a ring, and in that the electrical connection (41) of the inner winding (40) is electrically conductively connected to the arcing ring (15).
4. Circuit breaker according to Claim 3, characterized in that the electrical conductor (52) is in the form of a ring, and in that end surfaces of the inner winding (40) and of the outer winding (50) which are averted from the arcing ring (15) are supported on the ring.
5. Circuit breaker according to Claim 3, characterized in that the electrical conductor (52) is formed in the outer winding (50) and is in the form of a ring, and in that an end surface of the inner winding (40) which is averted from the arcing ring (15) is supported on the ring.
6. Circuit breaker according to one of Claims 1 to 5, characterized in that a ferromagnetic second sleeve (33) is provided, arranged coaxially, between the inner winding (40) and the outer winding (50).
7. Circuit breaker according to Claim 6, characterized in that at least one predominantly axially and radially guided slot (321, 331, 42, 53, 55) is arranged at least in the first sleeve (32) or the second sleeve (33), or in the electrical connection (41, 51), which is in the form of a ring, of the inner winding (40) or of the outer winding (50).
8. Circuit breaker according to Claim 7, characterized in that at least two slots (321, 331), which are distributed uniformly in the circumferential direction, are arranged in the first sleeve (32) and/or the second sleeve (33).
9. Circuit breaker according to one of Claims 7 or 8, characterized in that a first slot (53) is formed in the electrical connection (51) of the outer winding (50), and a second slot (42) is formed in the electrical connection (41) of the inner winding (40).
10. Circuit breaker according to Claim 9, characterized in that the first slot (53) and/or the second slot (42) are/is guided in the axial direction at most as far as a respective turn (54 or 43) on the outer winding (50) or on the inner winding (40), respectively, adjacent to the respective electrical connection (51 or 41) of the outer winding (50) or of the inner winding (40).
11. Circuit breaker according to Claim 10, characterized in that the first slot (53) and the second slot (42) extend radially in the same direction.
12. Circuit breaker according to one of Claims 10 or 11, characterized in that a third slot (55) is formed in the electrical conductor (52) which electrically conductively connects the inner winding (40) and the outer winding (50) to one another.
13. Circuit breaker according to Claim 12, characterized in that the first slot (53), the second slot (42) and the third slot (55) extend radially in the same direction.
14. Circuit breaker according to Claim 12, characterized in that at least two (53, 55) of the three slots (42, 53, 55) extend radially in different directions.

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