EP2099047B1 - Combustion contact device and output switch - Google Patents

Description

Technical area

The invention relates to a Abbrandkontaktanordnung for a circuit breaker and a circuit breaker comprising such Abbrandkontaktanordnung. Circuit-breakers of the type described are used in the high and medium voltage range of power distribution systems.

State of the art

Known Abbrandkontaktanordnungen often show in capacitive switching, especially of small currents, ie when switching off a capacitor bank, an unsatisfactory switching behavior. Because of the phase shift of 90 ° between current and voltage occurs about half a period after interruption of the current in the current zero crossing a voltage twice the mains voltage between the contact pieces. At this time, usually, the distance between the contact pieces is still relatively small and, since a positive pressure has built up in the arc space, which generates a very rapid flow around the tip of the contact pin, the dielectric strength in this area is greatly reduced because of the reduced gas density , This can easily lead to re-ignition.

Various burnout contact arrangements are known in which attempts have been made to counteract this. So is about in EP 1 306 868 A1 describes a consumable contact arrangement in which a contact tube cooperates with a thinner tip of a contact pin carried by a thicker shaft substantially filling the throat of a nozzle becomes. As a result, an immediate outflow of gas under overpressure from an arc space surrounding the end of the contact tube through the nozzle is prevented. However, the nozzle must be quite long, so that the throat is only free if the distance between the tip of the contact pin and the contact tube is so large that a re-ignition is no longer to be feared.

Out US 4,939,322 , Fig. 10 is a generic contact arrangement is known, in which the switching pin carries an annular plate which is located in the closed position just behind the throat of the nozzle and a terminal space, which follows the throat, is cylindrical and at the end facing away from the throat opening , dammed. The plate backs up the gas, thereby preventing the pressurized gas from abruptly flowing past the contact pin out of the arc chamber as soon as the contact pin releases the throat. The gas can only flow out when the plate is completely retracted from the terminal compartment. At this time, the distance between the contact pieces is already so large that there is no risk of re-ignition.

However, this Abbrandkontaktanordnung has the disadvantage that the terminal space and thus turn the nozzle that forms both this and the Engle must be relatively long, so that the outflow of the gas does not start too early. In addition, the lying between the Engnis and the plate part of the terminal compartment is relatively large already at the separation of the contact pin from the contact tube and inevitably increases linearly with the distance between the contact pieces, so that although a reduced, but still quite strong and not further influenced flow from the arc chamber in the connection space exits.

In the same document solutions are proposed which have the same disadvantages. In particular, a thin-tip and thickened-shaft switching pin is disclosed which is passed through a nozzle having one or more passages or throat areas, the cross-sections of the passages and tip being aligned with each other so that extinguishing gas can be stowed within the nozzle until the contact pin has reached a sufficient distance from the contact tube.

Presentation of the invention

The invention is based on the object to provide a generic Abbrandkontaktanordnung, which can be controlled so that it has a better switching behavior, especially in the capacitive switching relatively small currents. In addition, a circuit breaker should be specified, which has the same advantages.

These objects are achieved by the features of the independent claims. The Abbrandkontaktanordnung for a circuit breaker can be switched between a closed position and an open position and according to the invention comprises: a first contact piece and a second contact piece, which are in contact with each other in contact, an arc chamber, a nozzle of insulating material, which forms a throat, the preferred surrounds the second contact piece in the closed position, and with a following on the throat, facing away from the throat end open terminal space, with a relation to the terminal space or the nozzle displaceable gas retention element is present, which narrows in the closed position, the cross section of the terminal space, and which in the off position, the cross section of the terminal compartment largely and preferably fully releases, and wherein a position of the gas backflow element is controllable in the terminal compartment independently of the second contact piece.

The gas backflow element according to the invention prevents a rapid flow at speeds which may lie in the supersonic range around the tip of the contact pin as soon as the contact pin is withdrawn. Due to the independently controllable positioning of the gas flashback element in the terminal space adjoining the nozzle passage, a certain adjustable volume is made available to the quenching gas and a moderate, controllable extinguishing gas flow is permitted and at the same time an excessive pressure drop and density drop of the quenching gas are prevented.

Preferably, the gas retention element in the on position, the cross section of the terminal compartment largely and in particular completely block or dam, and / or the gas retention element can completely release the cross section of the terminal compartment in the off position.

In preferred embodiments, the second contact piece is displaceable independently of the gas retention element, and / or the gas retention element is independent of the second contact piece, in particular the same or opposite to this, displaced. Also, a position of the gas backflow element independently of the nozzle, in particular rectified and / or opposite to the nozzle, be movable. Furthermore, the gas backup element can be firmly connected to a housing of the circuit breaker.

The fact that the movement of the gas retention element or blocking element is not tied to that of the contact pin, it is also possible, the proportion of the terminal space, at a certain time of the Ausschaltvorganges - according to a certain position of the contact pin against the contact tube and the nozzle - free and which by the Blocking part should be separated, to steer. Thus, the flow from the arc chamber into the terminal compartment can be influenced in such a way depending on the distance between the contact pieces that the dielectric strength never drops so low that a re-ignition could occur. This is a decisive advantage, above all, in the case of capacitive switching, but it also has a favorable effect when large currents are switched, in which particularly fast currents can form due to strong back-heating.

Preferably, to limit the flow, the volume of the free part of the connection space can be increased later or slower than would be possible with a rigid coupling of the blocking element to the contact pin. This has the additional advantage that the connection space can be shorter, which in turn reduces the length of the Abbrandkontaktanordnung and the circuit breaker and saves space and cost.

Another object of the invention is a circuit breaker with such Abbrandkontaktanordung and a method for power interruption with such Abbrandkontaktanordung, wherein a Gasrückstau- or blocking element in the connection space between Düsenengnis and exhaust is present and obstructs at least temporarily during a switching operation, the gas outflow from the Düsenengnis and thereby keeps the density of the extinguishing gas in the arc zone high.

Brief description of the drawings

Fig. 1

schematisch einen Längsschnitt durch einen Teil eines erfindungsgemässen Leistungsschalters gemäss einer ersten Ausführungsform, oben in Einschaltstellung, unten in Ausschaltstellung,

Fig. 2

schematisch einen Längsschnitt durch einen Teil eines erfindungsgemässen Leistungsschalter gemäss einer zweiten Ausführungsform in Ausschaltstellung,

Fig. 3a-f

mehrere aufeinanderfolgende bei einer Ausschaltung des Leistungsschalters gemäss Fig. 1 durchlaufene Stellungen desselben und

Fig. 4

zeitliche Verläufe mehrerer bei einer Ausschaltung wesentlicher Spannungen.

In the following the invention will be explained in more detail with reference to figures, which represent only exemplary embodiments.
Show it

Fig. 1

schematically a longitudinal section through a part of an inventive circuit breaker according to a first embodiment, above in closed position, down in off position,

Fig. 2

1 is a schematic longitudinal section through part of a circuit breaker according to the invention in a switched-off position according to a second embodiment;

Fig. 3a-f

several consecutive at a circuit breaker according to Fig. 1 continuous positions of the same and

Fig. 4

temporal courses of several when switching off essential voltages.

Ways to carry out the invention

The Abbrandkontaktanordnung according to independent claim 1 according to the invention has a relative to the connection space 7 or the nozzle 2 displaceable gas retention element 19, which narrows the cross-section of the connection space 7, z. B. by forming a planar cross-sectional constriction in the connection space, and which releases the cross-section of the connection space 7 in the off position, z. B. by being outside the terminal compartment 7. The features of the dependent claims are optional and indicate preferred embodiments in any combination.

In Fig. 1 an example of a part of a circuit breaker is shown, which comprises a central Abbrandkontaktanordnung and cooperating with this pressure generating device and an outer rated current contact arrangement. Parts of the circuit breaker are shown only as far as they are essential for the function of Abbrandkontaktanordnung.

The consumable contact arrangement comprises a first contact piece designed as a contact tube 1 slotted in the end region, a fixedly connected to the same nozzle 2, which consists of an insulating material, and designed as a contact pin 3 second contact piece. An end portion of the contact tube 1 is surrounded by a sleeve 4, which also consists of an insulating material. The nozzle 2 forms a continuous central opening, which comprises an arc chamber 5, which extends when switching off between the first contact piece 1 and the second contact piece 3 and to which a cylindrical throat 6 adjoins. On the side facing away from the arc chamber 5 side of the throat 6, the opening, forming a typically conical transition zone or diffuser expands to a preferably cylindrical terminal compartment 7 of larger diameter, which is open at the opposite, the throat 6 opposite end by the den Connection space 7 enclosing wall breaks off as shown or another room of larger cross-section connects.

In principle, the nozzle can also have a plurality of passages, wherein the nozzle in turn merges into an expanding opening, which forms a transition zone or an end diffuser or main diffuser, to which the connection space adjoins. The transition zone is typically conical, but may also have a different contour. The damming by the inventive backflow element 19 for the backflow of quenching gas takes place mainly or preferably in the connection space 7, which is separated from the nozzle groove 6 through the end-side diffuser. On-site, throat 6 and connection space 7 may be made of the same material and, in particular, in one piece. In particular, the nozzle 2 may comprise the throat 6 and the connection space 7, the connection space 7 being widened with respect to the throat 6 and preferably extended continuously. Through a continuous expansion of the connection space 7 when retracting the backwater element 19 at a switch-off be released continuously or successively, so that a harmonious outflow of quenching gas is achieved.

The contact pin 3 protrudes in the closed position (above) through the connection space 7 and with a small lateral distance to the nozzle 2 through the throat 6 and further through the arc chamber 5. The tip of the contact pin 3 is located inside the contact tube 1 and fills the cross section just behind its end, where the cross section is the smallest, from, so that the contact tube 1, the contact pin 3 slightly behind the tip touches from the outside and thus contacted. In the off position (below), the tip of the contact pin 3 is approximately in the rear region of the connection space. 7

On the outside of the nozzle 2, a first tubular rated current contact 8 connects, which surrounds the contact tube 1 at a distance, so that between these parts a heating chamber 9 of a pressure generating device is located, which is connected via an annular channel 10 in the nozzle 2 with the arc chamber 5. The heating chamber 9 is separated from a compression chamber 12 by a connecting wall 11 connecting the contact tube 1 to the first rated current contact 8, which has openings provided with check valves. The pressure generating device further comprises a fixedly connected to the housing of the circuit breaker annular piston 13 which limits the compression space 12 at its end facing away from the intermediate wall 11 end.

Also firmly connected to the housing is a second tubular rated current contact 14 which surrounds the nozzle 2 at a distance and overlaps in the closed position with the first rated current contact 8 and touches it from the outside and contacted. The second rated current contact 14 carries inside a transverse wall 15 with a central opening through which the contact pin 3 is guided. Protrudes through another opening a rod 16 which is fixedly connected via a ring 17 with the nozzle 2.

The transverse wall 15, which is spaced from the end of the connection space 7 and thus the nozzle 2, also carries a support 18 projecting against the throat 6 and surrounding the contact pin 3, at the end of which an annular gas retention element or blocking element 19 is secured. It lies in the closed position near the front, the throat 6 facing the end of the terminal compartment 7, so just behind the throat 6 and fills the cross section of the terminal compartment 7, apart from the switching pin 3, largely completely. In the off position, it is located at a distance behind the opening 6 facing away from the throat 6 of the terminal compartment. 7

The illustrated part of the circuit breaker is surrounded by a non-illustrated tubular housing at a distance. The housing includes an exhaust space, with which the arc chamber 5 is connected through the interior of the contact tube 1 and also via the throat 6 and the terminal compartment 7. Further, it contains a drive to which the contact tube 1 is connected and the first rated current contact 8 and To the dme contact tube attached nozzle 2. About the means of the ring 17 rigidly connected to the nozzle 2 rod 16, the drive is further operatively connected to a gear that drives the pin 3. In an off, which transfers the circuit breaker and in particular the Abbrandkontaktanordnung from the on state to the off state, the drive of the contact tube 1 and the parts connected to it on the one hand and, on the other hand, via the gear, the contact pin 3 opposite movements.

Fig. 2 shows an embodiment which differs slightly from the above-described only insofar as the gas retention element 19 is not fixed to the housing of the circuit breaker is connected, but via a carried out by the transverse wall 15 stabfömigen carrier 18 'with another, also operatively connected to the drive gearbox. As a result, the position of the gas retention element 19 can be controlled independently of the nozzle 2 and / or the second contact piece 3, resulting in an overall somewhat more complicated construction.

With reference to Fig. 3a-f In the following section, the circuit breaker will be switched off in accordance with the conditions specified in Fig. 1 illustrated first embodiment, in which a capacitor bank is disconnected from the network. At the same time the some voltage curves will be shown Fig. 4 which on the time axis also references to some of the FIGS. 3a-f contains, which each show the circuit breaker in a position corresponding to the time.

From the switch-on position ( Fig. 3a ) is displaced by the drive, the contact tube 1 to the left, together with the parts connected to it, so that the first rated current contact 8 separated from the second rated current contact 14, so the rated current path is interrupted. The stream commutes completely to the burn-off path and flows over the contact tube 1 and the contact pin 3, which still overlap each other. At the same time, the reduction of the compression space 12 begins, which results in a compression of the extinguishing gas contained therein, eg SF ₆ ( Fig. 3b ).

In the course of further movement of the contact tube 1 and the onset of opposite movement of the contact pin 3, the contact pin 3 is completely pulled out of the contact tube 1 and separated to form an arc from the contact tube 2 ( Fig. 3c ). The arc extinguishes at the next current zero crossing under the action of the from the compression chamber 12 via the heating chamber 9 and the annular channel 10 in the arc chamber 5 and through the contact tube 1 in the Exhaust space flowing extinguishing gas. As a result, however, the capacitor bank maintains its voltage, which corresponds to the full line voltage because of the phase shift of 90 ° between current and voltage at the current zero crossing.

While the contact pin 3 is further away from the end of the contact tube 1, the contact voltage U _K between these contact pieces thus increases to twice the line voltage within a half period T / 2 (solid line in FIG Fig. 4 ) at. But at the same time increases with the distance between the contact pieces and also under the action of the further quenching gas flow in the arc chamber 5 and the breakdown voltage U _D (dotted line), in such a way that it is always higher than the contact voltage U _K and thus no reignition occurs ,

Even at the time when the contact pin 3 is completely withdrawn from the throat 6 ( Fig. 3d ), occur no high, in particular no supersonic currents in the region of the tip of the contact pin 3, since the gas flashback element 19 has released up to this time only a relatively small volume and the connection of the connection space 7 with the exhaust space almost completely blocked. The length of the released volume corresponds only to the stroke of the contact tube 1 relative to the housing up to this time, while the stroke of the contact pin 3 does not affect said volume. The flow from the arc chamber 5 through the throat 6 into the connection space 7 is therefore so slight that the dielectric strength does not noticeably drop and the breakdown voltage U _D continues to increase unchecked. The drawn for comparison voltage U _V (dashed line), which shows the course of the breakdown voltage in the absence of the gas backpressure element 19, but with the rest of the same structure of the circuit breaker and the beginning of something Slower increase, since the flow through the throat 6 would be greater in this case, kinks significantly at this time, ie it grows slower with the distance of the contact pieces or the time t, so that it is finally surpassed by the contact voltage U _K and backfire entry.

As soon as the gas retention element 19 has completely left the connection space 7 ( Fig. 3e ), the gas flow from the arc chamber 5 via the throat 6 and the terminal compartment 7 in the exhaust room abruptly increases. This leads to a brief drop in the breakdown voltage U _D , which drops to the value of the reference voltage U _V and does not differ from this in the following. However, at this time t = 3e, the distance between the contact pin 3 and the contact tube 1 is already so great that the dielectric strength is still sufficient and the breakdown voltage U _D always remains greater than the contact voltage U _K. The further removal of the contact pin 3 from the contact tube 1 and the quenching gas flow from the compression chamber 12 and the heating chamber 9, continue until finally the switch-off ( Fig. 3f ) is reached, lead to a further increase in the breakdown voltage U _D such that a flashback is excluded.

In the Fig. 2 As already mentioned, the embodiment shown offers the possibility of controlling the position of the gas retention element 19 independently of the nozzle 2 and / or independently of the second contact piece 3. Thus, the gas retention element 19 can first be moved in the same direction as the nozzle 2, either so that they completely follows their movement or something remains, so that the shared part of the terminal compartment 7 at first not or only slowly increases and hardly any flow from Arc space 5 occurs in the terminal compartment 7. Once the distance between the contact pieces is large enough to ensure a sufficiently high breakdown voltage, the movement of the gas flashback element 19 can be stopped or the gas flashback element 19 in the opposite direction - ie in the same direction as the contact pin 3 - moves and withdrawn from the terminal compartment 7.

It is possible to depart substantially from the described embodiments without departing from the scope of the invention as claimed in the claims. In particular, it does not matter which parts of the circuit breaker are stationary and which are not. Decisive are the relative movements of the parts, especially of nozzle, contact pin and gas retention element. The circuit breaker can z. B. a blow piston switch, a Selbstblasschalter, further a high or medium voltage switch, and a switch with a single movement of a contact piece or with dual drive for both contacts.

LIST OF REFERENCE NUMBERS

1

contact tube

2

jet

3

pin

4

shell

5

Arcing area

6

throat

7

connection space

8th

first rated current contact

9

boiler room

10

annular channel

11

partition

12

compression chamber

13

piston

14

second rated current contact

15

partition

16

pole

17

ring

18, 18 '

carrier

19

Blocking element, backflow element for extinguishing gas

Claims (19)

1. Arcing contact arrangement for a circuit breaker, which is switchable between a switched-on position and a switched-off position, having a first contact piece (1) and a second contact piece (3), which make contact with one other in the switched-on position and are moveable relative to one another, having an arcing chamber (5), and having a nozzle (2), made from insulating material, which forms a constriction (6) that surrounds the second contact piece (3) in the switched-on position, and having a connection chamber (7) which is downstream of the constriction (6) and is open at an end remote from the constriction (6), characterized in that a gas back-pressure element (19), which is displaceable relative to the connection chamber (7) or the nozzle (2), is present and constricts the cross section of the connection chamber (7) in the switched-on position and substantially frees the cross section of the connection chamber (7) in the switched-off position, and in that a position of the gas back-pressure element (19) in the connection chamber (7) is controllable independently of the second contact piece (3).
2. Arcing contact arrangement according to Claim 1, characterized in that the second contact piece (3) is displaceable independently of the gas back-pressure element (19).
3. Arcing contact arrangement according to one of the preceding claims, characterized in that the gas back-pressure element (19) is displaceable independently of the second contact piece (3), in particular in that the gas back-pressure element (19) is moveable in the same direction as and/or in the opposite direction from the second contact piece (3).
4. Arcing contact arrangement according to one of the preceding claims, characterized in that a position of the gas back-pressure element (19) is controllable independently of the nozzle (2), in particular in that the gas back-pressure element (19) is moveable in the same direction as and/or in the opposite direction from the nozzle (2).
5. Arcing contact arrangement according to one of the preceding claims, characterized in that the gas back-pressure element (19) is rigidly connected to a housing of the circuit breaker.
6. Arcing contact arrangement according to one of the preceding claims, characterized in that the gas back-pressure element (19) substantially blocks, and in particular completely blocks, the cross section of the connection chamber (7) in the switched-on position, and/or in that the gas back-pressure element (19) completely frees the cross section of the connection chamber (7) in the switched-off position.
7. Arcing contact arrangement according to one of the preceding claims, characterized in that

   a) in the switched-on position, the gas back-pressure element (19) lies in the connection chamber (7), and/or

   b) in the switched-off position, the gas back-pressure element (19) lies outside the connection chamber (7).
8. Arcing contact arrangement according to one of the preceding claims, characterized in that, in the switched-on position, the gas back-pressure element (19) is close to the end of the connection chamber (7) nearest to the constriction (6) and, in the switched-off position, is close to or behind the opposite end of the connection chamber (7) remote from the constriction (6).
9. Arcing contact arrangement according to one of the preceding claims, characterized in that the tip of the second contact piece (3) is pushed back behind the constriction (6) in the switched-off position.
10. Arcing contact arrangement according to one of the preceding claims, characterized in that the connection chamber (7) is widened relative to the constriction (6), preferably widened throughout, particularly preferably widened continuously, and/or in that the connection chamber (7) has a constant cross section.
11. Arcing contact arrangement according to one of the preceding claims, characterized in that the constriction (6) of the nozzle (2) and/or the connection chamber (7) are cylindrical, and/or in that the constriction (6) and the connection chamber (7) are connected to one another by means of a conical transition zone, and/or in that the nozzle (2) forms the constriction (6) and the connection chamber (7).
12. Circuit breaker having a arcing contact arrangement according to one of the preceding claims, and having a drive which is suitable for effecting a switching-off operation in which the arcing contact arrangement is transferred from the switched-on position to the switched-off position, characterized in that the drive is operationally connected to the arcing contact arrangement in such a way that, when the contacts are broken, the gas back-pressure element (19) is able to be pulled back out of the connection chamber (7) in a manner which is at least temporarily delayed and/or slowed and/or in the opposite direction relative to the second contact piece (3).
13. Circuit breaker according to Claim 12, characterized in that it comprises a pressure-generating device having a compression chamber (12) connected to the arcing chamber (5), and having a piston (13) which limits the compression chamber (12) in such a way that, when the contacts are broken, said piston is displaceable, relative to the nozzle (2), towards the arcing chamber (5).
14. Circuit breaker according to Claim 13, characterized in that the compression chamber (12) surrounds the first contact piece (1), and in that the piston (13) limits the compression chamber (12) on one side.
15. Circuit breaker according to one of Claims 12 to 14, characterized in that it comprises a housing and in that the second contact piece (3) and the nozzle (2) are operationally connected to the drive in such a way that, when the contacts are broken, they move in opposite directions relative to the housing, while the gas back-pressure element (19) is rigidly connected to the housing.
16. Circuit breaker according to one of Claims 12 to 14, characterized in that it comprises a housing and the second contact piece (3), the nozzle (2) and the gas back-pressure element (19) are operationally connected to the drive in such a way that, when the contacts are broken, the second contact piece (3) and the nozzle (2) move in opposite directions relative to the housing and the gas back-pressure element (19) firstly moves in the same direction as the movement of the nozzle (2) and then in the opposite direction.
17. Circuit breaker according to one of Claims 12 to 16, characterized in that it contains at least one exhaust chamber, which, at least in the switched-off position, opens into the connection chamber (7).
18. Circuit breaker according to one of Claims 12 to 17, characterized in that the first contact piece (1) is formed as a contact tube (1) and the second contact piece (3) is formed as a contact pin (3), which, in the switched-on position, is contactable from the outside by the contact tube (1).
19. Circuit breaker according to one of Claims 12 to 18, characterized in that the arcing chamber (5) is connected to the at least one exhaust chamber via the opening in the contact tube (1).

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