EP2402970B1 - Arc chamber for a medium- or high-voltage circuit breaker with reduced operating energy and dimensions - Google Patents

Description

TECHNICAL AREA

The invention relates to a breaking chamber for use in a medium or high voltage circuit breaker typically in the range of 7.2 kV to 800 kV.

By convention, it is specified here that the terminology "high voltage circuit breaker" includes circuit breakers that can be classified in the ultra-high voltage category, i-e beyond 550 kV.

An interesting particular application is the use in an alternator circuit breaker.

PRIOR ART

In this particular application in which it is necessary to be able to cut a high short circuit current, typically 40 kA or more, the design must be provided so that the opening and closing maneuvers of the three-pole circuit breaker can be realized. only by the operation of a low energy mechanism control, usually a spring latch mechanism which is located outside the interrupt chambers.

However, the mass and dimensions (volumes) required for the parts through which the short-circuit current increases with the value of the latter.

The maneuvering energy required to move them to cut the short-circuit current accordingly increases to the point where it is no longer possible to use low-energy mechanism controls that are standard.

To solve this problem, various alternative solutions to an oversizing of the external controls have been proposed.

These alternative solutions have in common to provide a fixed blowing nozzle which allows to have the heavier parts fixed.

Thus, the patent FR 2,435,118 describes a solution which consists in integrating a coil spring 20 inside the interrupting chamber, which is compressed during a closing operation by the external control and whose function is to compress the arc-blowing gas present in a blowing volume during an opening maneuver. Referring to the embodiment of Figures 5 and 6 of this patent, the helical spring 20 bearing against the blowing piston 15 formed integrally and around an arcing contact 18 is compressed during the closing operation by the other arc contact 21 connected to the control. During an opening maneuver, the helical spring 20 expands and thus compresses the gas present in the blast volume 30. During the breaking of high currents, the pressure in this volume 30 is further increased by the heating of the gas from the arc energy 25.

The main disadvantage of this solution is that the piston 15 is pushed in the opposite direction (to the left on the Figures 5 and 6 ) when the pressure is increased by the arc energy. The blowing volume 30 is then increased, which tends to lower the pressure of the blowing gas during the cut. Another disadvantage is that the arc blow is limited to single blow through the nozzle 27b.

This same patent FR 2,435,118 proposes in its embodiment of Figures 36 and 37 means which in theory are able to overcome the main disadvantage: these means consist of latches 43 arranged at the edge of the blast volume 30 and actuated by leaf springs 44 which are provided to be housed in grooves 45 formed in the piston 15 and thus lock in translation in the detent position of the spring 20 which compressed the gas. In practice, it turns out that these mechanical translation locking means 43, 44, 45 of the piston can not be effective in recent self-blow-off chambers in which the pressure variations are too high (up to 60 bar and more). In other words, the mechanical translation locking means 43, 44, 45 can not actually block the piston 15 when breaking high short circuit currents.

The patent EP 0 441 292 discloses a solution similar to the previous one and which furthermore consists of the short-circuit operation illustrated in FIGS. Figures 3 and 4 to realize a double flow of blowing from the volumes V1 and V4 in parallel towards the arc contact 4A and through the nozzle 16. However, the volume V1 increases during the breaking of high currents and as a result the overpressure generated for the cut is decreased. Another disadvantage is that the two arcing contacts 4A, 7A may repel each other when breaking high short-circuit currents if the force of the spring 13 is not sufficient. In addition, the blows in parallel from each other respectively volumes V1, V4 tend to interfere with each other. To try to solve the disadvantages of the circuit breaker according to this patent EP 0 411 292 it has been proposed a refinement in the application FR 2683382 . The design of the interrupting chamber according to this application is satisfactory on one point: there are no more volumes of blowing in parallel since a single volume of thermal expansion V1 + V4 is provided. Thus there is more risk of mutual disruption of blowing. At the time of this application (1991), the arrangement of an additional permanent contact 30, 31 inside the blast nozzle 16 and at the end of the fixed cylinder 9 could be envisaged to effectively limit the length of the the arc created during the power failure and thus avoid excessive pressure increase in the thermal expansion volume V4 and thus any decline of the movable piston 8 which is connected to the movable contact 4. At this time, the short circuit currents to be cut for the circuit breaker according to this application FR 2683382 were at most equal to 25 kA, which resulted in pressures in the thermal expansion volume of up to ten bars. Even by oversizing the compression spring 13 with necessarily an oversize of the external control, such a circuit breaker could not be considered currently because the short-circuit currents to be cut are even higher (up to 63kA) with pressures generated up to at 70 bars. It is also not certain that a compression spring 13 oversized to the extreme does not withstand these pressures. In other words, the solutions according to the patent EP 0 441 292 and the demand FR 2683382 can not be applied for high short-circuit currents (> 25kA).

The patent WO 2006/066420 discloses another solution which consists of cooling the arc which occurs between the arcing contacts 4 and 5 by a gas blowing generated from the volume 24, as schematized in FIG. figure 1 of this patent. The pressure increase in the volume 24 is performed by the compressed gas from the volume 27 through the channel 29 and simultaneously by the heating of the gases caused by the energy of the arc.

A disadvantage of this solution is that the volume 27 is arranged on an outer diameter of the volume 24. This outer diameter is wide and tends to increase the diameter of the insulators 3, 3c.

Another disadvantage of this solution is that the blowing piston 28 and the arc contact 4 must be moved by the same mechanism by means of a complex linkage because of the different races to be performed for each moving part and that the linkage must have complete compression in the volume 27 when the arc is established between the arc contacts 4 and 5.

The Applicant has proposed a break chamber design solution that does not have the drawbacks of the aforementioned prior art and which requires a low maneuvering energy: this solution was the subject of the French patent application filed August 14 2009 under the number FR 09 55677 .

Although satisfactory, the inventors then sought to further improve this solution by simplifying its implementation and decreasing the transverse dimensions (diameter) of the interrupting chamber to finally obtain a reduced diameter, or insulation for high-voltage circuit breakers. type "Live tank" or metal tank for those type "GIS" (English "Gas Insulated Switchgear") or type "Dead tank".

• en appui mécanique à la fois contre l'autre contact permanent et contre l'autre contact d'arc en position de fermeture, c'est-à-dire lors du passage de courant permanent ;
• à distance à la fois de l'autre contact d'arc et de l'autre contact permanent lors de l'ouverture, c'est-à-dire lors de la coupure d'un courant d'arc, jusqu'à la position d'ouverture complète.

It is known from the prior art that it is possible to reduce the transverse dimensions (diameter) of a high-voltage circuit-breaker breaking chamber by conferring on a contact a dual function at the same time of passage of the arc current ( short circuit) and the permanent current and arranging the other permanent contact coaxially and in the vicinity of the other arcing contact, that is to say substantially the same diameter. The kinematics and the arrangement provided thus make it possible to put the contact with double arc function and permanent:

• in mechanical support both against the other permanent contact and against the other contact arc in the closed position, that is to say during the passage of permanent current;
• remote from both the other arcing contact and the other permanent contact during the opening, that is to say during the breaking of an arc current, to the position full opening.

Thus, the patent US 5, 258,590 discloses a cutting chamber of small external diameter thanks to the compact arrangement of two arc contacts 8, 9, tubular so-called end and permanent contact 2. More precisely, one of the contacts of arc 8 is fixed and the other 9 is movable, and their ends 8 ', 9' are supported against each other in the closed position. The fixed arcing contact 8 also constitutes a permanent contact, the other permanent contact 2 also being in tubular and mobile form, and arranged coaxially and close to the other arcing contact 9. At the opening the arcing and permanent contact 8 at the end abutment against the other arcing contact 9 slides in abutment with the interior of the other permanent contact 2 until their separation from which the arc is created (see figure 3 ). The major disadvantage of this solution is that the moving parts are heavier since they comprise the blowing chamber 5, the blowing nozzle, the other arc contact 9 and the other permanent contact 2. In other words, the operating energy of a breaking chamber according to this patent US 5, 258,590 can be considered relatively high.

The patent US 4, 511, 776 also discloses a breaking chamber with a compact arrangement of two arc contacts 5, 6 in tubular form and a permanent contact 4. The arc contact 5 is fixed and the other 6 is movable and they are arranged coaxially and distance one in the other in the closed position. The movable arcing contact 6 is also a permanent contact, the other permanent contact 4 being in tubular and fixed form and arranged coaxially with the fixed arcing contact 5. In the closed position, the arcing contact and permanent 6 mobile is in peripheral support with the permanent contact 4 and around and away from the other arc contact 5. During the opening, the arc contact and permanent slides while being in peripheral support with the interior of the other permanent contact 4 until their separation from which the arc is created (see figure 1 ).

The major disadvantage of this solution is that there is not really a gas compression chamber but a suction in the gas exhaust zone from the chamber 11. In other words, such a break chamber according to the patent US 4, 511,776 can not be adapted in high-voltage circuit-breakers for which gas compression is imperative for the breaking of weak currents. In addition, the arrangement of the contacts provided involves the use of a movable arcing contact 6 with a very thin end portion 6A to be able to be inserted between the other arcing contact 5 and the other contact. permanent 4. Such geometry of contacts can not be adopted in a high-voltage circuit breaker as this would necessarily imply a too high electric field in the arc zone.

The object of the invention is thus to propose a breaking chamber which does not have the drawbacks of the prior art and which requires a low operating energy, in particular in case of high short-circuit current failure (≥ 40 kA), which is simple to make and which has compact transverse dimensions.

STATEMENT OF THE INVENTION

• dont l'énergie de manoeuvre est réduite en prévoyant une conception comme dans la demande de brevet susmentionnée N° FR 09 55677 ,
• avec des dimensions réduites par l'agencement compact des contacts permanents et d'arc en conférant judicieusement à l'un d'entre eux la fonction double de contact permanent et d'arc et à l'autre contact d'arc mobile la fonction de support du piston de soufflage, c'est-à-dire la fonction de liaison temporaire mécanique entre ce dernier et le contact à la fonction double (permanent et d'arc).

For this purpose, the subject of the invention is a breaking chamber according to claim 1. Thus, the invention essentially consists in defining a breaking chamber:

• whose maneuvering energy is reduced by providing a design as in the aforementioned patent application No. FR 09 55677 ,
• with dimensions reduced by the compact arrangement of the permanent and arc contacts by judiciously conferring on one of them the double function of permanent contact and arc and the other movable arc contact the function of support of the blow piston, that is to say the function of temporary mechanical connection between the latter and the contact with the double function (permanent and arc).

• définir un volume de soufflage figé et une buse de soufflage fixe afin de réduire la masse mobile de la chambre de coupure et par là l'énergie cinétique,
• générer une augmentation de pression dans le volume de soufflage principalement par l'échauffement des gaz en courants élevés, et avoir une augmentation de pression par le volume de compression pour les coupures en faibles courants,
• réaliser les contacts d'arc et permanents sur un diamètre réduit correspondant sensiblement à celui du tube d'un contact d'arc usuel, ce qui permet de réduire les dimensions transversales de la chambre de coupure,
• avoir des contacts d'arc en appui d'extrémité, aussi appelée en bout, qui peuvent avoir des plots ou bourrelets d'extrémité à rayon de courbure important, ce qui permet d'avoir un champ électrique plus faible et une meilleure tenue aux courants élevés avec une usure réduite,
• conférer judicieusement la fonction support de piston à l'un des contacts d'arc mobiles qui sert donc également de moyen de liaison temporaire entre ledit piston et l'autre contact d'arc mobile,
• produire une compression des gaz, approximativement jusqu'à ce que les contacts d'arc soient séparés, et uniquement par un ressort hélicoïdal qui pousse le piston solidaire de l'un des contacts d'arc mobiles et ainsi réduit le volume de compression, l'augmentation de pression étant alors transmise au volume de soufflage par l'ouverture d'une valve. Le ressort est par ailleurs agencé juste derrière le piston et est comprimé durant une opération de fermeture en étant poussé par les contacts d'arc mobile. L'énergie nécessaire à la compression du gaz est ainsi minimisée du fait de la proximité du ressort avec le volume de compression,
• obtenir une manière simple de déplacer le piston et les contact d'arc mobiles avec leurs courses respectives nécessaires, la course du contact d'arc mobile lié à la tige de manoeuvre étant égale à la course de compression du piston plus une course supplémentaire pour obtenir une distance suffisante entre les contacts d'arc en position ouverte (suffisamment élevée pour réaliser la coupure de courant quelle que soit sa valeur et pour obtenir la tenue diélectrique du disjoncteur),
• définir une géométrie à double flux de soufflage,
• avoir la possibilité d'utiliser une commande de manoeuvre extérieure au disjoncteur qui fournit une énergie au juste nécessaire pour fermer les contacts et pour manoeuvrer le contact d'arc mobile lié à la tige lors de l'ouverture.

In other words, the invention consists in:

• define a fixed blowing volume and a fixed blast nozzle in order to reduce the moving mass of the breaking chamber and thereby the kinetic energy,
• generating a pressure increase in the blowing volume mainly by heating the gases in high currents, and having a pressure increase by the compression volume for the cuts in small currents,
• making the arcing and permanent contacts on a reduced diameter substantially corresponding to that of the tube of a conventional arc contact, which makes it possible to reduce the transverse dimensions of the interrupting chamber,
• have end-end arc contacts, which may also have ends or ends with a large radius of curvature, which makes it possible to have a weaker electric field and better resistance to currents high with reduced wear,
• suitably conferring the piston support function on one of the movable arcing contacts which thus also serves as a temporary connection means between said piston and the other movable arcing contact,
• producing a compression of the gases, approximately until the arcing contacts are separated, and only by a helical spring which pushes the piston secured to one of the movable arcing contacts and thus reduces the compression volume, pressure increase is then transmitted to the blowing volume by the opening of a valve. The spring is also arranged just behind the piston and is compressed during a closing operation by being pushed by the moving arc contacts. The energy required for the compression of the gas is thus minimized because of the proximity of the spring to the compression volume,
• obtain a simple way of moving the piston and the movable arcing contacts with their respective necessary strokes, the stroke of the movable arcing contact connected to the actuating rod being equal to the compression stroke of the piston plus an additional stroke to obtain a sufficient distance between the arcing contacts in the open position (sufficiently high to achieve the power failure regardless of its value and to obtain the dielectric strength of the circuit breaker),
• define a geometry with double flow of blow,
• have the possibility of using a circuit breaker external control command that provides energy just needed to close the contacts and to manipulate the movable bow contact connected to the rod during opening.

• un volume de soufflage V2 figé et qui n'est pas augmenté avec les augmentations importantes de pression durant les coupures de courant élevées,
• une chambre de soufflage avec une forme standard telle que celle utilisée dans les disjoncteurs à haute tension modernes, et qui débouche par un canal de diamètre réduit sur la zone ou se produit l'arc,
• un double flux de gaz de soufflage sur l'arc.

Compared to cut-off rooms according to the documents FR 2,435,118 , EP 0 441 292 , US 5258590 and US 4511776 mentioned in the preamble, the breaking chamber according to the invention presents:

• a blown volume V2 that is not increased with the significant increases in pressure during the high power outages,
• a blow molding chamber with a standard shape such as that used in modern high-voltage circuit breakers, and which opens with a small diameter channel on the area where the arc occurs,
• a double flow of gas blowing on the arc.

• un diamètre plus faible des pièces actives de l'agencement de la chambre de compression derrière celle de soufflage,
• des contacts d'arc et permanents de diamètres réduits et donc des dimensions transversales externes de la chambre de coupure réduites,
• un mécanisme plus simple pour déplacer le piston et les contacts mobiles dont le contact d'arc à double fonction d'arc et permanent,
• une plus grande efficacité du fait de la proximité du ressort avec le volume de compression,
• une forme de la chambre de soufflage et une forme de canal reliant la chambre de soufflage à la zone d'arc standard, comme usuellement utilisés dans les disjoncteurs à haute tension. Cela permet d'avoir un mélange optimal entre gaz chauds et froids dans le volume de soufflage.

Compared with a break chamber according to the patent WO 2006/066420 mentioned in the preamble, the breaking chamber according to the invention presents:

• a smaller diameter of the active parts of the arrangement of the compression chamber behind that of blowing,
• arcing contacts and permanent reduced diameters and therefore external transverse dimensions of the reduced cutting chamber,
• a simpler mechanism for moving the piston and the movable contacts whose arc-dual and permanent arc contact,
• greater efficiency due to the proximity of the spring with the compression volume,
• a shape of the blow chamber and a channel shape connecting the blow chamber to the standard arc area, as commonly used in high voltage circuit breakers. This makes it possible to have an optimal mixture between hot and cold gases in the blowing volume.

According to an advantageous embodiment, the interrupting chamber may comprise sliding guide means of the movable permanent arc contact connected to the actuating rod, arranged between said movable contact and a supply or output contact of current from outside the interrupting chamber, the sliding guide means being further adapted to allow the passage of current between the supply contact or output contact and the arc contact and moving permanent. These sliding guiding means may consist of rollers mounted between the contacts or alternatively by a widening section of the arc contact and moving permanent. Thus, a simple and effective guide of the arcing contact and permanent of its closed position in which it is in end support with the other arcing contact and in peripheral support with the other permanent contact in its position extreme opening in which any current is cut off.

According to another advantageous embodiment, the moving arc and permanent contact is indirectly linked to the operating rod by mechanical transmission means adapted to increase the speed ratio in translation between the moving arc and permanent contact and the operating rod. This further reduces the operating energy by increasing, preferably doubling, the speed of translation of the arc contact and permanent with respect to the speed of actuation of the operating rod.

According to an alternative embodiment, the transmission means comprise at least one pinion whose axis of rotation is fixed to the operating rod, a first rack being arranged fixedly in the breaking chamber and a second rack fixed to the contact. mobile and permanent arc, the first and second rack being arranged diametrically opposed to each other with respect to the diameter of the pinion. This variant is advantageous because it uses few components assembled in a simple manner.

The invention relates to a high or medium voltage circuit breaker, comprising, for a pole, one or more breaking chambers described above.

BRIEF DESCRIPTION OF THE DRAWINGS

• les figures 1 à 5 représentent un mode de réalisation d'une chambre de coupure selon l'invention en vue de coupe longitudinale et selon différentes positions depuis la fermeture des contacts jusqu'à l'ouverture extrême des contacts et la coupure réalisée,
• la figure 6 représente une vue de détail d'une variante de réalisation d'une chambre de coupure selon l'invention en vue de coupe longitudinale.

Other advantages and characteristics of the invention will emerge more clearly on reading the detailed description given with reference to the following figures:

• the Figures 1 to 5 represent an embodiment of a breaking chamber according to the invention for longitudinal cutting and in different positions since the closing of the contacts to the extreme opening of the contacts and the cut made,
• the figure 6 is a detail view of an alternative embodiment of a breaking chamber according to the invention for longitudinal sectional view.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

The current interrupting chamber 1 for a medium or high voltage circuit breaker D according to the invention extends along a longitudinal axis (XX ') and firstly comprises an insulating envelope 10 in which a pair of permanent contacts 2 is arranged. , One of which, in the form of a tulip, is fixed and the other 3, in the form of a tube, is movable along the longitudinal axis (XX ') under the action of an operating rod 4 itself arranged in another insulating envelope 40.

It also comprises a pair of arc contacts 5, 6 both movable along the longitudinal axis (XX '). The permanent contacts 2, 3 and arc 5, 6 are provided to separate each other during a power failure. The travel in translation of the movable contact 5 is sufficiently high to achieve the power failure regardless of value and to obtain the dielectric strength of the circuit breaker.

It is furthermore provided with an arc-blowing nozzle 7 integral with the fixed permanent contact 2. As illustrated, the insulating blast nozzle and the permanent contact 2 are fixed to an outlet contact 8 of the current towards the outside of the the chamber via a fixed metal part 9 forming a support.

A blowing chamber 70 defined by the fixed part 9 and the arc-blowing nozzle 7 defines a fixed volume V2 and which opens inside the blast nozzle 7 fixed by a channel 700 of small diameter to bring the gas blowing towards the zone of arc formed between the contacts 5, 6 during a break. It is therefore specified here that the volume V2 is therefore the thermal expansion volume for the high currents to be cut.

A compression chamber 71 defines a volume V1 which varies and opens into the blowing chamber 70 under the action of a piston 60. The chambers The compression 71 and blowing 70 are substantially arranged one behind the other parallel to the longitudinal axis XX '.

The compression chamber 71 and the blowing chamber 70 are separated by a valve 701. The valve setting 701 is designed to open by the overpressure generated in the compression chamber 71 by the movable piston 60. In the event of a break in high currents (≥ 40 kA), the arc energy produces an overpressure in the fixed thermal expansion volume V2, which causes the closure of the valve 701.

A helical spring 11 is fixed by one of its ends directly to the piston 60 and by the other of its ends to the output contact 8 of the current to the outside of the interrupting chamber.

The breaking chamber 1 further comprises temporary mechanical connection means between the piston 60 and the moving arcing contact 5 connected to the actuating rod for compressing the spring 11 against the piston 60 during a maneuver. closing the permanent contacts 2, 3 and arc 5, 6 and to obtain a stroke of the movable arcing contact 5 greater than the stroke of the spring 11 which compresses the volume V1. Furthermore, the compression of the gas in the volume V1 is performed approximately as soon as the arcing contacts 3, 5 are separated ( figure 3 ).

• le contact d'arc mobile 5 lié à la tige de manoeuvre constitue en outre le contact permanent mobile 3,
• les moyens de liaison temporaire sont constitués par l'autre contact d'arc 6, également mobile en appui d'extrémité contre l'extrémité du contact d'arc mobile 5 lié à la tige de manoeuvre, l'autre contact d'arc mobile 6 étant solidaire du piston de soufflage 60,
• le contact permanent fixe 5 est agencé coaxialement et en appui périphérique avec le contact d'arc mobile 6 lié à la tige de manoeuvre 4 en position de fermeture jusqu'à une position intermédiaire d'ouverture (figure 2) dans laquelle il est en appui périphérique avec le contact d'arc mobile 6 solidaire du piston de soufflage 60.

According to the invention and as illustrated Figures 1 to 5 :

• the movable arc contact 5 connected to the actuating rod constitutes, in addition, the moving permanent contact 3,
• the temporary connection means are constituted by the other arcing contact 6, also movable in end support against the end of the moving arcing contact 5 connected to the operating rod, the other movable arcing contact 6 being integral with the blowing piston 60,
• the fixed permanent contact 5 is arranged coaxially and in peripheral support with the movable arcing contact 6 connected to the operating rod 4 in the closed position to an intermediate opening position ( figure 2 ) in which it is in peripheral support with the moving arcing contact 6 integral with the blowing piston 60.

In addition, a mechanical stop (not shown) is provided to block the moving arcing contact 6 integral with the blowing piston 60 in a locking position corresponding to or close to the intermediate opening position ( figure 2 ) of peripheral support with the permanent contact, said locking position constituting the position of separation of the arc contacts facing the blast channel 700.

In the embodiment of Figures 1 to 5 , metal rollers 30 are arranged between the supply contact 12 of the nominal current from outside the chamber and the arcing contact and moving permanent 3, 5. These rollers 30 and allow the sliding guide of the latter of its closed position ( figure 1 ) to its extreme opening position ( figure 5 ). These metal rollers 30 furthermore ensure the passage of the nominal current of the supply contact 12 in contact with the arc and permanent moving 5.

The operation of the breaking chamber will now be better explained with reference to Figures 1 to 5 .

In figure 1 the high voltage circuit breaker is in the closed position, ie in a position permitting the passage of a permanent nominal current from the supply contact of the current 12 from the outside of the breaking chamber 1 to the output contact 8 of the current to the outside of the chamber, the nominal current flowing through the permanent contacts 2, 3 in mutual peripheral support. The compression spring 11 bearing against the blowing piston 60 is in the compressed state. This compressed state is maintained by the two arcing contacts 5, 6 at end support or in other words end-to-end, the moving arcing contact 5 connected to the operating rod (to the right on the figure 1 ) being held in position by the locked operation control.

In figure 2 an opening maneuver to turn off the power is started. The operating rod 4 is pulled (from left to right in the figures), the arc contact and moving permanent contact 3, 5 which is connected thereto following the movement as well as the other movable arcing contact 6 in support end due to the thrust exerted by the spring 11 in abutment against the blowing piston integral with said arc contact 6. The stiffness of the spring is sufficient to maintain the end support between arc contacts 5, 6 At the same time, the blowing piston 60 compresses the gas in the compression chamber 71. In this intermediate opening position of the figure 2 , the nominal current in both the arcing contact and permanent contact 3, 5, in the movable arcing contact 6 in end support with the latter and in the stationary permanent contact 2 itself in peripheral support with the movable arc contact 6.

In figure 3 , the mechanical stop not shown has locked in translation the blowing piston 60 and thus the movable arcing contact 6 which is integral. The latter has its end opposite the edge of the blast channel 700. The movable and permanent arc contact 3, 5 which is connected to the operating rod 4 is always in translation: there is no longer in this position end support blocking between the two arcing contacts 5, 6. In other words, it is the position of separation of the two arcing contacts 5, 6. The current no longer transits and an electric arc is created and generates an overpressure in the chamber 70 by heating through the channel 700.

In figure 4 the translation of the arcing and permanent contact 3, 5 has continued, which increases the separation distance with the other arcing contact 6 in the locking position and thus lengthens the arc. At a given moment, the current goes to zero and the blowing gases from the compressed volume V1 and issued in the volume V2 by the valve 701 and those heated in the volume V2 blow the arc and cool. The arc current is then cut.

The figure 5 illustrates the extreme opening position of the movable contacts 3, 5 and 6 or otherwise says the open position of the high voltage circuit breaker D.

In the embodiment illustrated in Figures 1 to 5 the operating rod 4 and the movable permanent arc contact 3, 5 are directly connected to one another, ie with a transmission ratio in translation equal to 1.

To further reduce the operating energy of the breaking chamber according to the invention, it is possible to provide mechanical means for increasing this transmission ratio, that is to say means making it possible to accelerate the translation of the contact. bow and mobile standing 3, 5. As shown in detail view in figure 6 these mechanical means of increasing the transmission ratio advantageously consist of a double rack system 130, 310, one of which is fixed and the other integral with the movable and movable arcing contact, each of the two racks meshing with a fixed pinion 41 of the operating rod 4. More exactly and as illustrated in figure 6 , there is provided a first rack 130 made on a fixed support 13 in the interrupting chamber or in the insulating jacket portion 40 in which is housed the operating rod 4. An axis 410 is mounted at the end of the operating rod 4 and constitutes the axis of rotation of the pinion 41. The second rack 310 is integral with the arcing contact and movable permanent 3, 5 and arranged being diametrically opposed with the first rack 130 relative to the diameter of the pinion 41. Thanks to such system of racks 130, 310 and pinion 41 secured to the operating rod 4, the translation speed of the arcing contact and moving permanent 3, 5 is doubled with respect to the speed of translation of the operating rod 4. In other words, when the pinion 41 is moved a distance X ₁ in the breaking chamber by the operating rod 4, the arcing contact and permanent 3, 5 moves for the same period of time on a double distance 2X ₁ , which doubles its speed of translation.

To ensure the electrical continuity between the supply contact 12 of the current from outside the chamber and the arcing and movable permanent contact 2 may be provided instead of metal rollers 30, a sectional enlargement 31 on the contact of bow and permanent 3, 5 ( figure 6 ). Provision is furthermore made to conform the supply contact in the form of a tulip 120. During a maneuver, the tulip 120 then slides on the enlargement of section 31 of the contact 3, 5.

Other improvements may be provided without departing from the scope of the invention.

Thus, it is possible to provide one or more corona shields in the breaking chamber 1 for reducing the electric field on the movable and permanent arcing contact 3, more particularly in the extreme open position as shown in FIG. figure 5 .

If in the illustrated mode of the figure 6 , the first rack 130 is arranged in the inner part of the fixed support 130, it can be provided on the outer part 131. In this case, the arc contact 3, 5 is made so that the pinion 41 s' meshes between this upper portion 131 of the fixed support 13 and a lower part of a tube additional cylinder connected to the operating rod 4. This is explicitly shown in figure 1 of the patent application filed today in the name of the plaintiff under the number FR 55323 and entitled "Breaker Room for High and Low Voltage Circuit Breakers with Reduced Maneuvering Energy".

It can also be provided that the fixed support 13 supporting the rack 130 constitutes a supply or output contact of the nominal current from or to the outside of the interrupting chamber.

The tulip 120 and the fixed support 13 can also be made in one piece in order to simplify the geometry of the breaking chamber according to the invention and to facilitate its assembly.

Finally, in the embodiment of Figures 1 to 5 , the mechanical stop of the piston 60 is arranged in an intermediate position of the compression chamber such that the volume V1 is not completely compressed when the movable contact 6 is blocked by said stop ( figure 5 ). It is also possible that this stop is constituted by the bottom of the compression chamber so that the volume V1 is completely compressed when the movable contact 6 is blocked.

Whatever the compression of the volume V1 envisaged with the aid of the blowing piston 60 mobile, the thermal expansion volume 70 remains constant / frozen and the pressure that may occur therein can not disturb the displacement piston 60 under the action of the spring 11, and this for any value of the current to be cut.

Claims (7)

1. Arc chamber (1) for a medium or high voltage circuit breaker (D) extending along a longitudinal axis (XX') and comprising:

   - a pair of permanent contacts (2, 3), of which one (2) is fixed and the other (3) is movable along the longitudinal axis (XX') under the action of an operating rod (4) to which it is connected, for mutually separating between a closed position in which a nominal current can flow through and an open position in which the current is interrupted,

   - a pair of arc contacts (5, 6), of which one (5) is movable along the longitudinal axis (XX') under the action of the operating rod to which it is connected, the translational travel of the movable contact being sufficiently high to carry out the current interruption regardless of its value and to obtain the dielectric strength of the circuit breaker,

   - an arc-blowing nozzle (7) that is secured to the fixed permanent contact (2),

   - a blowing chamber (70) the volume V2 of which is fixed, said blowing chamber opening into the interior of the fixed blowing nozzle through a blowing channel (700) for supplying the blowing gas to the zone where the arc formed between the arc contacts occurs during an interruption,

   - a compression chamber (71) the volume V1 of which varies, said compression chamber opening into the blowing chamber under the action of a piston (60), the compression chamber being arranged substantially behind the blowing chamber (70) parallel to the longitudinal axis XX',

   - a helical spring (11) attached, at one of its ends, directly to the piston (60) and at the other of its ends to a fixed part (8),

   - means for temporary mechanical connection between the piston (60) and the arc contact (5) that is movable under the action of the operating rod (4) in order to compress the spring (11) directly attached to the piston during an operation for closing the contacts and in order to obtain a travel of the movable arc contact that is greater than the travel of the spring that compresses the volume V1, said compression of the gas in the volume V1 being moreover carried out approximately as soon as the arc contacts are separated,

   wherein:

   - the movable arc contact (3) connected to the operating rod (4) constitutes, in addition, the movable permanent contact (5),

   - the temporary connection means are formed by the other arc contact (6), which is also movable with its end resting against the end of the movable arc contact (5) connected to the operating rod, the other movable arc contact (6) being secured to the blowing piston (60),

   - the fixed permanent contact (2) is arranged coaxially and with its periphery resting against the movable arc contact (5) connected to the operating rod in the closed position up to an intermediate open position,

   and the arc chamber comprises a mechanical stop for blocking the movable arc contact that is secured to the blowing piston in a blocking position corresponding to or in the vicinity of the intermediate open position,
   said blocking position constituting the separation position of the arc contacts facing the blowing channel (700),
   characterised in that:

   in the intermediate open position, the periphery of the fixed permanent contact (2) rests against the movable arc contact (6) that is secured to the blowing piston, and in that the compression chamber (71) and the blowing chamber (70) are separated by a valve (701), the valve (701) setting being provided to open said valve by means of an overpressure generated in the compression chamber (71) by the movable piston (60).
2. Arc chamber according to claim 1, comprising sliding guide means of the arc and movable permanent contact (3, 5) connected to the operating rod (4), arranged between said movable contact (3, 5) and a contact for current supply (12) or current output from outside the arc chamber, the sliding guide means being further adapted to allow the passage of current between the supply (12) or output contact and the arc and movable permanent contact (3, 5).
3. Arc chamber according to claim 2, wherein the sliding guide means consist of running rollers (30) mounted between the contacts.
4. Arc chamber according to claim 2, wherein the sliding guide means are formed by a section widening (31) of the arc and movable permanent contact (3, 5).
5. Arc chamber according to any one of claims 1 to 4, wherein the arc and movable permanent contact (3, 5) is indirectly connected to the operating rod by mechanical transmission means adapted to increase the translational speed ratio between the arc and movable permanent contact and the operating rod.
6. Arc chamber according to claim 5, wherein the transmission means (130, 310, 41, 410) comprise at least one pinion (41) whose axis of rotation (410) is attached to the operating rod (4), a first rack (130) thereof being fixedly arranged in the arc chamber and a second rack (310) attached to the movable and permanent arc contact (3, 5), the first (130) and second (310) racks being arranged diametrically opposite each other with respect to the diameter of the pinion (41).
7. Upper-intermediate or high voltage circuit breaker (D), comprising, for a pole, one or more arc chambers (1) according to any of the preceding claims.

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