EP0454035A1 - Medium or high voltage circuit breaker with about-turn arc-contacts - Google Patents

Abstract

High- or medium-voltage circuit breaker with end arc contacts, comprising a sealed insulating envelope (1) filled with a gas with good dielectric properties, inside which are arranged a fixed arc contact (3-3A), a moving arc contact (7-7A) driven by an operating rod (26) actuated by a mechanism outside the envelope, a blast chamber (17) comprising a piston (9) integral with the moving arc contact and able to slide in a fixed cylinder (14), and a blast nozzle (12), characterised in that it comprises means (24) such that the operating rod moves over a given length without driving the said arc contact. …<IMAGE>…

Description

The present invention relates to a circuit breaker with end arcing contacts, usable at medium or high voltage.

Circuit breakers with end arc contact are known, comprising a sealed envelope filled with gases having good dielectric properties such as sulfur hexafluoride, and in which the arc is blown by compression of the gas during an operation of opening. In circuit breakers of this type, gas compression occurs before the separation of the arcing contacts (this is called precompression); during this precompression phase, the main contacts of the circuit breaker are opened, which can be arranged outside the enclosure; the disadvantage of the precompression phase is that it requires significant operating energy which increases the cost of the device.

An object of the present invention is to provide a circuit breaker with arc blast at the end, arc blowing requiring only reduced energy for its operation.

The subject of the invention is a high or medium voltage circuit breaker with end arcing contacts, comprising a sealed insulating envelope filled with a gas having good dielectric properties, inside which a fixed arcing contact are arranged. , a movable arcing contact driven by an operating rod actuated by a mechanism external to the casing, a blowing chamber comprising a piston integral with the movable arcing contact and capable of sliding in a fixed cylinder, and a blowing nozzle , characterized in that it comprises means so that the operating rod moves over a given length without causing said arcing contact.

For example, said movable arcing contact is a tube, said means comprising a light provided in the tube in which is engaged an arm secured to the operating rod.

In an embodiment which can preferably be used in high voltage, the circuit breaker comprises fixed permanent contacts mechanically and electrically connected to said fixed arcing contact and cooperating with a tube constituting a mobile permanent contact connected to said operating rod.

• la figure 1 est une vue schématique en coupe axiale d'un disjoncteur selon un premier mode de réalisation, représenté en position enclenchée,
• la figure 2 est une vue en coupe axiale du même disjoncteur, représenté au début d'une manoeuvre de déclenchement,
• la figure 3 est une vue en coupe axiale du même disjoncteur, représenté en fin de manoeuvre de déclenchement,
• la figure 4 est une vue en coupe axiale d'un disjoncteur selon un second mode de réalisation de l'invention, représenté en position enclenchée.

The invention will be better understood from the description given below of two embodiments of the invention, with reference to the appended drawing in which:

• FIG. 1 is a schematic view in axial section of a circuit breaker according to a first embodiment, shown in the engaged position,
• FIG. 2 is a view in axial section of the same circuit breaker, shown at the start of a tripping operation,
• FIG. 3 is a view in axial section of the same circuit breaker, shown at the end of the tripping operation,
• Figure 4 is an axial sectional view of a circuit breaker according to a second embodiment of the invention, shown in the engaged position.

In FIG. 1, the reference 1 designates a cylindrical insulating envelope, for example of porcelain, which delimits an interior volume 2, tight and filled with a gas with good dielectric properties such as sulfur hexafluoride, pure or mixed with nitrogen, under a pressure of a few bars.

The fixed arcing contact of the circuit breaker consists of a metal tube 3, connected to a block 4 passing through the casing in a sealed manner and connected to a first socket 5. The end 3A of the tube 3 is made in a alloy resistant to the effects of the arc, for example based on tungsten. Block 4 is drilled, inside the envelope 1, a channel 6 to promote the circulation of gas inside the envelope.

The movable arcing contact consists of a metal tube 7, the end of which 7A which cooperates with the tube 3 is also made of an arc-resistant alloy. The tube 7 has, towards its end opposite to the end 7A, at least one lateral bore 7B for the evacuation of the gas.

The tube 7 is integral with a blowing piston 9, provided with orifices 10 and associated with a cylinder 11 carrying a blowing nozzle 12 made of insulating material.

The piston 9 slides in a first bore 14 of a metal block 15 resting on the internal face of the insulating column 1. This block 15 comprises a metal crown 16, coming from milling, which delimits, with the piston 9 and the wall of the bore 14 a blowing volume 17. The crown carries a central hole not referenced in which slides the tube 7. Furthermore, the crown 16 is pierced with at least one hole 18 associated with a unidirectional valve, which can be simply constituted by a flexible washer 19, and which allows the passage of gas only from the outside to the inside of the volume 17.

The block 15 is pierced with a channel 15A parallel to the axis of the column and making the volumes located on either side communicate.

The tube 7 is fixed, by a screw 20, to a metal cylinder 21 integral with an annular guide piece 22 which can slide in a second bore 23 of the block 15.

The part 22 is pierced with holes 22A.

The cylinder 21 has a slot 24 in which is engaged an arm 25 connected to a rod 26 articulated on a connecting rod 27 of the operating device, which further comprises a crank 28 wedged on a rotary shaft 29 driven by an operating device not shown , outside the envelope 1.

A spring 30, bearing on the ring 22, tends to push back the arm 25.

The cylinder 21 is electrically connected, by a braid 31, to a second socket 32 fixed to the block 15 and passing through the envelope in a sealed manner.

• en position enclenchée, (cas de la figure 1), la majeure partie du courant passe par les contacts principaux, extérieurs à l'enveloppe 1, non représentés, connectés électriquement en parallèle sur les contacts d'arc et possédant leur propre organe de manoeuvre.

The circuit breaker works as follows:

• in the engaged position (case of FIG. 1), most of the current flows through the main contacts, external to the casing 1, not shown, electrically connected in parallel on the arcing contacts and having their own operating member .

• à l'ouverture, un ordre est donné à l'organe de manoeuvre et l'arbre 29 se met à tourner. Dans une première phase, le bras 25 est entraîné à l'intérieur de la lumière 24, sans entraîner les cylindres 21 et 7, ni provoquer aucune précompression dans le volume 17. La détente du ressort 30 aide à la manoeuvre. Cette première phase est mise à profit pour commander l'ouverture des contacts principaux; le courant est alors commuté sur les contacts d'arc et traverse la prise 5, le bloc 4, le tube 3-3A, le tube 7-7A, le tube 21, la tresse 31 et la prise 32. La figure 2 montre la disposition des éléments du disjoncteur pendant cette première phase.
• lorsque le bras 25 atteint l'extrémité de la lumière 24, le tube 21 et par suite, le contact d'arc mobile 7-7A est entraîné. Un arc jaillit et est soufflé par le gaz du volume 17, comprimé par le déplacement du piston 9 et s'échappant à travers la buse 12 dès que le passage est libre. La figure 3 illustre la fin de cette seconde phase pendant laquelle le gaz du volume 17 est comprimé.

The ends of the arcing contacts 3A and 7A touch; the spring 30 is bandaged.

• at the opening, an order is given to the operating member and the shaft 29 starts to rotate. In a first phase, the arm 25 is driven inside the lumen 24, without driving the cylinders 21 and 7, or causing any precompression in the volume 17. The relaxation of the spring 30 helps the maneuver. This first phase is used to control the opening of the main contacts; the current is then switched on the arcing contacts and passes through the socket 5, the block 4, the tube 3-3A, the tube 7-7A, the tube 21, the braid 31 and the socket 32. Figure 2 shows the arrangement of the circuit breaker elements during this first phase.
• when the arm 25 reaches the end of the lumen 24, the tube 21 and consequently, the movable arcing contact 7-7A is driven. An arc erupts and is blown by the gas of volume 17, compressed by the displacement of the piston 9 and escaping through the nozzle 12 as soon as the passage is free. FIG. 3 illustrates the end of this second phase during which the gas in volume 17 is compressed.

Thanks to the arrangements which have just been described, the maneuvering energy is reduced since there is no compression of the gas until the arc has burst. In in addition, the operating rod gains speed during the first phase, so that the arcing contacts separate very suddenly at the start of the second phase, which promotes cutting.

The embodiment which has just been described relates to a circuit breaker, preferably at medium voltage, in which the main contacts are outside the envelope containing the breaking chamber.

The variant embodiment of the invention, shown in FIG. 4, relates to a circuit breaker used in high voltage, with main contacts placed inside the breaking chamber.

In FIG. 4, the elements common to this figure and to the preceding figures have been designated by the same reference numbers.

The metal block 4 carries contact fingers 40 constituting the fixed permanent contact of the circuit breaker. The movable permanent contact consists of a metal tube 41 connected by arms 41A and a bar 41B, to an operating rod made of insulating material 42. The blowing cylinder is a tube 43 sliding inside the tube 41 and in connection electric with the latter by sliding contacts 44. The bottom 45 of the cylinder 43 is fixed by metal arms 46 secured to a fixed metal block 47 crossed by the insulating rod 42; at least one of the arms 46 is connected to the second socket 32. The bottom 45 of the cylinder 43 is pierced with a central hole through which passes a metal tube 48 constituting the movable arcing contact and provided with a end of material resistant to the effects of the arc; this tube has a light 48A in which the bar 41B is engaged; moreover, a spring 50 is disposed between the bar 41 B and a ring 51 of the tube 48.

Inside the cylinder 43 slides a blowing piston 52, integral with the movable contact 48 and provided with orifices 53.

The bottom 45 of the cylinder 43 is provided with sliding contacts 55 to ensure the electrical connection between this bottom and the movable arcing contact; moreover, this bottom 45 is provided with a unidirectional valve 56 authorizing the passage of gas only from the outside towards the inside of the blowing volume 57 delimited by the cylinder 43, the bottom 45 and the piston 52. The piston 52 is extended by a metal cylinder 58 which can slide inside the cylinder 43 and carrying a blowing nozzle 60 made of insulating material.

• en position enclenchée, le disjoncteur est dans la configuration représentée dans la figure 4. La barre 41B est en haut de la lumière 48A, le ressort 50 est bandé, le volume de soufflage est maximal. Le courant traverse alors la prise 5, le bloc 4, les doigts 40, le tube 41, les contacts glissants 44, le cylindre 43, le fond 45, les bras 46 et la prise 32.
• lorsque l'ordre d'ouverture est donné, la tringle isolante se déplace vers le bas de la figure. Pendant une première phase, correspondant au parcours par la barre 41B de la lumière 48A, le cylindre 41 est seul entraîné, provoquant la séparation des contacts permanents. Pendant cette phase, le piston 52 reste immobile, de sorte qu'aucune précompression du gaz n'intervient.
• lorsque la barre 41B atteint l'extrémité basse de la lumière, le tube 48 est entraîné, provoquant la séparation des contacts d'arc 3A et 48B, ainsi que la compression du volume de soufflage 57.

The circuit breaker works as follows:

• in the engaged position, the circuit breaker is in the configuration shown in FIG. 4. The bar 41B is at the top of the light 48A, the spring 50 is bandaged, the blowing volume is maximum. The current then passes through the socket 5, the block 4, the fingers 40, the tube 41, the sliding contacts 44, the cylinder 43, the bottom 45, the arms 46 and the socket 32.
• when the opening order is given, the insulating rod moves down the figure. During a first phase, corresponding to the path through the bar 41B of the light 48A, the cylinder 41 is only driven, causing the separation of the permanent contacts. During this phase, the piston 52 remains stationary, so that no precompression of the gas takes place.
• when the bar 41B reaches the lower end of the lumen, the tube 48 is driven, causing the separation of the arcing contacts 3A and 48B, as well as the compression of the blowing volume 57.

Again, thanks to the arrangement which has been described, the energy required for the operation is low, since there is no precompression before the separation of the arcing contacts; this intervenes suddenly, thanks to the speed acquired by the moving equipment during the first phase.

This alternative embodiment is preferably used for high voltage circuit breakers.

Claims (3)

High or medium voltage circuit breaker with end arcing contacts, comprising a sealed insulating jacket (1) filled with a gas having good dielectric properties, inside which a fixed arcing contact (3-3A) are arranged ), a movable arcing contact (7-7A) driven by an operating rod (26) actuated by a mechanism external to the casing, a blowing chamber (17) comprising a piston (9) integral with the contact movable arc which can slide in a fixed cylinder (14), and a blowing nozzle (12), characterized in that it comprises means (24) so that the operating rod moves over a given length without causing said contact arc. Circuit breaker according to claim 1, characterized in that said movable arcing contact (7-7A) is a tube, said means comprising a light (24) formed in the tube in which an arm (25) integral with the rod is engaged operating (26). Circuit breaker according to claim 2, characterized in that it comprises fixed permanent contacts (40) mechanically and electrically connected to said fixed arcing contact (3-3A) and cooperating with a tube (41) constituting a mobile permanent contact connected to said operating rod (42).

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