EP0986081A1 - High voltage circuit breaker with resistance insertion system with long duration insertion - Google Patents

Abstract

The circuit breaker is held in a gas filled envelope (1) and has a contact section (2) and second contact section (3) following the longitudinal direction. There is a resistance (R) which is inserted using auxiliary sliding contacts (7A,7B). The contacts are brought into contact during switch closing.

Description

The invention relates to a compressed gas switch, in particular a high voltage circuit breaker, comprising in an envelope which extends in a direction longitudinal, a first set of contacts including a first permanent current contact and first contact arcing, a second movable contact assembly according to the longitudinal direction with respect to the first crew of contacts and including a second permanent contact and a second arcing contact intended to connect respectively at the first permanent contact and at the first arcing contact, and a resistance insertion system during closing of the switch, this resistor being connected electrically in series between the first arcing contact and the first permanent current contact.

Such resistance serves to limit the effects of transient currents on the network when closing the switch. In practice, this resistance is inserted when is established, when the switch closes, an electrical connection between the arcing contacts and is short-circuited before the connection between the permanent current contacts. When opening the switch, the resistor must not be inserted.

The duration of insertion of this resistance may vary from one installation to another. This duration is generally dependent on the speed at which the crew is moved of mobile contacts. Some switches allow to obtain an insertion time of the order of 6 ms for a moving speed of the moving contact assembly of around 4 m / s. Some installations require the use of switches to reach a much longer resistance insertion time, of the order of 14 ms.

An object of the invention is to propose a system insertion of a resistance to obtain a duration insertion of significant resistance.

Another object of the invention is to propose a system insertion of a closing resistor which is compact and which requires few parts.

To this end, the invention relates to a switch compressed gas comprising, in an envelope which extends in a longitudinal direction, a first crew of contacts including a first permanent current contact and a first arcing contact, a second set of contacts movable in the longitudinal direction relative to the first contact crew and including a second contact permanent and a second arcing contact intended to connect respectively at the first permanent contact and at the first arcing contact, and a resistor insertion system when the switch closes, this resistance being electrically connected in series between the first arcing contact and the first permanent current contact, characterized in that the insertion system of the resistance includes two auxiliary contacts, the first is electrically connected to the first contact of permanent current and the second is connected to the first contact arcing, in that these two auxiliary contacts are mounted moving relative to each other in the direction longitudinal so as to be able to approach one of the other, when the switch closes, to establish a connection that bypasses the resistor and so as to be united in displacement following the longitudinal direction, when closing the switch, before establishing said connection which short-circuits resistance.

With such an arrangement, a duration is obtained insertion of the resistance corresponding to the duration necessary for the two auxiliary contacts to closer to each other to which is added the duration of displacement of the two auxiliary contacts when they are related to each other on the go.

According to a particular embodiment of the switch according to the invention, the first arcing contact has the shape of a rod on which a metal block slides carrying the second auxiliary contact and this block is pushed in the longitudinal direction, when closing the switch, by a nozzle secured to the second contact arc. Thus, the duration of insertion of the resistance can be set to the speed of movement of the crew of mobile contacts.

According to yet another particular embodiment of the switch according to the invention, the block has a substantially conical end which fits into the nozzle. In this way, we remove the shock effect on the block when the switch closes, which contributes to put the block in motion at the same speed as the contact mobile.

According to yet another particular embodiment of the switch according to the invention, the block includes a tubular extension which extends in the direction longitudinal and on which an insulating piece slides integral with the first auxiliary contact, the extension tubular having an end forming a piston which cooperates with a recess in the insulating part of such so that the piston is made integral with the part insulating, when the switch closes, through play a depression created in the recess of the insulating part between the piston and the insulating part. We therefore understand that the auxiliary contacts are linked in displacement, during the closing of the switch, by a pneumatic system simple suction effect that requires no linkage.

According to yet another embodiment of the switch according to the invention, the block includes an internal chamber which is divided by a radial shoulder of the stem of the first arcing contact, and in which a spring is placed in the chamber against the radial shoulder of the rod in such a way that moving the block along the stem of the first arcing contact, when the switch closes, causes the spring to compress as the chamber fills with gas and that when opening the switch, the spring when relaxing exerts a force recall which tends to automatically move the block in opposite direction at the same time as the gases are evacuated from the chamber through an orifice thereof, the orifice being further calibrated for resistance against the force of spring reminder. Such an arrangement makes it possible to obtain simple way with few parts and by pneumatic means, when the switch is opened, a disconnection of the auxiliary contacts effective only after disconnection of arcing contacts and current contacts permanent. Resistance cannot be inserted during opening the switch.

According to yet another particular embodiment of the switch according to the invention, the first contact auxiliary and the first permanent current contact are mounted integral on a tube movable in the direction longitudinal, and in which a spring is arranged against the movable tube to oppose the movement of this tube in the longitudinal direction, when closing the switch, this spring exerting a restoring force during of the switch opening which tends to move automatically the tube in said longitudinal direction and in a contrary direction.

An example of embodiment of the switch according to the invention is described below in more detail and illustrated in the drawings.

Figure 1 shows very schematically a switch according to the invention in open position complete.

Figure 2 shows very schematically the switch of Figure 1 in a first position intermediate closure.

Figure 3 shows very schematically the switch of figure 1 in a second position intermediate closure.

Figure 4 shows very schematically the switch of Figure 1 in a third position intermediate closure.

Figure 5 shows very schematically the switch of Figure 1 in a fourth position intermediate closure.

Figure 6 shows very schematically the switch of Figure 1 in a closed position complete.

In the figures and more particularly in the figure 1, the switch shown is a switch used for very high voltage. It includes in an envelope insulating or metallic 1 of substantially cylindrical shape, for example in porcelain, which extends in a direction longitudinal D, a first movable contact assembly 2 in direction D and a second set of contacts 3. The envelope is normally filled with a dielectric gas like SF6 under a pressure of a few bars to form a switching chamber.

The switch shown in the figures presents a symmetry of revolution in direction D.

The switch includes at the end of the break on the side of contact 3, resistance R which is conventionally inserted into the electrical circuit of the switch when closing it.

The moving contact assembly 2 includes a contact permanent current 2A in the form of a crown of metal fingers and a hollow arc contact 2B also in the form of a crown of metallic fingers, the hollow arc contact 2B being arranged coaxially in contact 2A according to the direction D. These movable contacts 2A and 2B are carried by a 2C tube fitted with a piston (not shown) of gas compression to extinguish the arc upon opening of the switch as is well known. 2C tube also carries a 2D gas pipeline nozzle, the diverging, which is coaxial with contacts 2A and 2B following the direction D, opens with a diverging tulip on the side of the contact crew 3. The contact crew 2A, 2B with the 2D nozzle is moved in translation in the direction D by an operating member of the switch not shown.

In alignment with the moving contact assembly 2, the contact arrangement 3 includes a current contact permanent 3A which is in the form of a crown of metal fingers arranged coaxially along the direction D at the crown of fingers of contact 2A and a arcing contact in the form of a rod 3B (possibly hollow) which extends in the direction D coaxially to the contact finger ring 2B. At the closing of the switch, the arcing contact in the form of a rod 3B fits into the movable hollow arc contact 2B through the 2D nozzle and the 3A contact engages the contact 2A.

Resistor R is maintained in an insulating support 4 which is integral with the rod of the arcing contact 3B and extends in the direction D. This resistor R is connected electrically in series between the arcing contact 3B and the permanent current contact 3A although this does not appear not in the figures.

A metal block 5 is slidably mounted on the rod 3B in electrical contact with it via of accordion contacts 6. Block 5 has one end of substantially conical shape adapted to fit into diverging from the nozzle neck and present on the surface outside of this conical end a bead peripheral 5A on which the edge of the the opening of the diverging portion of the 2D nozzle.

This block 6 carries a first auxiliary arcing contact 7A which is in the form of a crown of fingers and which cooperates with a second auxiliary arcing contact 7B in the form of a tube, these two arcing contacts auxiliaries 7A and 7B used to short-circuit the resistance R when the switch closes.

More specifically, the fingers of contact 7A extend in direction D towards resistance R and the contact tube 7B extends in opposite direction, that is to say to the moving contact assembly 2.

The auxiliary contact 7B is electrically connected to the 3A permanent current contact via a metal tube 8 which is mounted movable in the direction D in the envelope 1, on another fixed metal tube 9 in the envelope and which surrounds the resistance R. The tube metallic 8 is in electrical contact with the tube metallic 9 by means of sliding contacts 8A.

Block 5 which carries the auxiliary contact 7A comprises an internal chamber 10 which is sealed through by rod 3B of the fixed arcing contact of crew 3, on which it slides. This room 10 is divided by a radial shoulder 11 of rod 3B (forming a sort of piston) on which a spring 12 is supported. Chamber 10 has 5B calibrated orifices allowing exhaust gases from inside the chamber 10. The spring 12 is compressed when block 5 is moved in direction D from top to bottom in Figure 1.

Block 5 is extended by a tubular portion 5C which extends in the direction D by surrounding the rod 3B. An insulating part 13 is slidably mounted on this tubular portion 5C. The tubular portion 5C has a enlargement of the perimeter which forms a 5D piston suitable for come and break into an obviously 13A complementary to part 13. The piston 5D has valves 5E oriented in such a way that the gases in the recess 13A can be freed from this obviously when the 5D piston inserts in this obviously.

The part 13 is integral with the tube 8 by through an insulating support cone 14 so that the tube 8 and therefore the contacts 3A and 7B are integral in movement in direction D with the insulating part 14.

A spring 15 is disposed between the tube 8 and a shoulder of the tube 9. This spring 15 is compressed when the tube 8 is moved in direction D from top to bottom on Figure 1. In addition, the stroke of the tube 8 from top to bottom in Figure 1 is stopped by a stop formed by the end of the tube 9 and the insulating cone 14.

As shown in Figure 1, in the switch in fully open position, arcing contacts auxiliaries 7A and 7B are separated by a certain distance dAX which can be used to adjust the insertion time of the resistance when closing the switch. In addition, this resistance insertion time can be adjusted by the distance dAX 'which corresponds to the stroke of the tube 8 until the insulating cone abuts against the edge of tube 9.

The operation of the insertion system of the resistance when closing the switch is now the next one.

Figure 1, the switch is in the fully positioned opened. Contacts 2A, 2B and 7A are separate contacts 3A, 3B and 7B respectively. The 5D piston is fully inserted into the recess 13A; there is no gas at the interface between the piston 5D and the insulating part 13 which creates depression.

Figure 2, a switch closing operation has begun. Crew 2 begins a closing race in direction D in the direction indicated by arrow F. Contacts 2A and 2B are brought closer to contacts 3A and 3B and an electric arc is created first between the contacts arc 2B and 3B. Current therefore flows from arcing contact 2B towards the arcing contact 3B. By construction the distance dAX is large enough to avoid arcing electric between the auxiliary arcing contacts 7A and 7B. The current therefore crosses the rod of the arcing contact 3B and the resistance R which is inserted into the electrical circuit of the switch. During this first phase of closure, the 2D nozzle was moved at the same time as the 2A contacts and 2B and struck the bead 5A on the surface tapered from the front end of block 5. However, this conical end of block 5 was first inserted gradually in the tulip-shaped diverging of the 2D nozzle which means that it will be set in motion without oscillations due to shock.

Figure 3, crew 2 moved slightly by relative to its position in Figure 2, in the direction of the arrow F. Contacts 2A and 2B are still closer contacts 3A and 3B but the distance dCP between the contacts 2A and 3A is still sufficient to avoid striking an electric arc. Block 5, pushed by the 2D nozzle, also moved slightly following the direction D in the direction of arrow F which resulted in a corresponding displacement DP of piston 5D in the recess 13A of the insulating part 13. This slight displacement created a vacuum at the interface between the 5D piston and the part insulating 13. Note that the distance dAX between the contacts auxiliary arc 7A and 7B also decreased slightly but remains sufficient to avoid arcing between these contacts. Current always flows through the contact arcing 2B, arcing contact 3B and resistance R which is inserted.

Figure 4, crew 2 still moved by relative to its position in Figure 3, in the direction of the arrow F. The arcing contact 3B in the form of a rod is now inserted in the hollow arc contact 2B and the 2A and 3A permanent current contacts are always separate a sufficient distance dCP to avoid arcing electric. The 2D nozzle moving with the 2A contacts and 2B pushed block 5 in direction D in the direction of the arrow F causing the compression of the spring 12 between the shoulder 11 and the block 5 and the gas inlet, by via a 5F valve, in chamber 10 of the block 5. At the same time, the 5D piston at the end of the portion tubular 5C of block 5, caused by a suction effect the insulating part 13 in the direction of the arrow F which makes that the tube 8 has also moved in the direction D in the direction of arrow F by compressing the spring 15. It it is understood that the power of the spring 15 must be less than the suction force exerted by the 5D piston on the insulating part 13. Because the tube 8 and the block 5 moved together and in the same direction, the auxiliary arcing contacts 7A and 7B remained separate a distance dAX sufficient to avoid any ignition of a electric arc. Therefore, the current always flows in the arcing contact 2B, the arcing contact 3B and the resistance R which remains inserted. In Figure 4, the cone support 14 comes into abutment against the end of the tube 9 of so that the tube 8 is blocked in movement according to the direction D in the direction of arrow F.

Figure 5, crew 2 still moved by relative to its position in Figure 4, in the direction indicated by arrow F. The rod-shaped arc contact 3B has inserted even more into the hollow arc contact 2B and the permanent current contacts 2A and 3A are still close together while remaining sufficiently remote to avoid arcing. Block 5 was still pushed by the 2D nozzle in the direction of the arrow F and the spring 12 is even more compressed. Because the tube 8 is in abutment in the direction of the arrow F, the pushing of block 5 by the 2D nozzle causes a withdrawal of the piston 5D of the recess 13A in the insulating part 13. The suction effect is therefore eliminated. Arc contact auxiliary 7A approaches the auxiliary arcing contact 7B until the distance dAX is small enough to that an electric arc is created between these two contacts. This connection between the two contacts 7A and 7B short-circuits resistance R the current therefore crosses the 2B arcing contact, 3B arcing contact, contacts accordion 6, metal block 5, arcing contact auxiliary 7A, auxiliary arcing contact 7B, tube 8, accordion contacts 8A and tube 9.

Figure 6, the switch is completely closed. The contacts 2A, 2B and 7A are connected to contacts 3A, 3B and 7B respectively, the connection of the current contacts permanent 2A and 3A established after connection of auxiliary arcing contacts 7A and 7B. Compared to the position of the switch in FIG. 5, block 5 a still been pushed in the direction of arrow F by the 2D nozzle and the spring 12 has been further compressed. Because the piston 5D was no longer interdependent in movement with the insulating part 13, the spring 15 has relaxed and exerted a restoring force which moved the tube 8 and therefore the contacts 3A and 7B in the opposite direction to arrow F. The tube 8 therefore returned to the position he occupied on the Figure 1 when the switch was fully open.

When the switch opens, crew 2 is moved at high speed in the opposite direction to the arrow F with the 2D nozzle. 2A permanent current contacts and 3A separate first, then the arcing contacts 2B and 3B. Block 5 no longer undergoing thrust from the nozzle 2D, automatically moves in the same direction as the moving part 2 by the play of the restoring force exerted by spring 12 (which relaxes) at the same time as the gas in the chamber 10 of the block 5 is discharged through the orifices 5B. These holes are calibrated as indicated above so that resistance to the return force of spring 12 is exerted which makes block 5 move more slowly than crew 2 in the opposite direction to arrow F. results that the auxiliary arcing contacts 7A and 7B remain connected a while after the separation of the contacts arcs 2B and 3B so that the resistor also remains short-circuited when opening the switch. When the block 5 returns to the position it occupied in FIG. 1, the piston 5D is inserted again into the recess 13A of the insulating part 13 and the gases at the interface of the piston 5D and of the insulating part 13 are expelled by the valve 5E.

Claims (6)

A compressed gas switch comprising, in a casing (1) which extends in a longitudinal direction (D), a first set of contacts (2) including a first permanent current contact (2A) and a first arcing contact (2B), a second contact assembly (3) movable in the longitudinal direction relative to the first contact assembly and including a second permanent contact (3A) and a second arcing contact (3B) intended to connect respectively to the first permanent contact and at the first arcing contact, and a resistor insertion system (R) when the switch closes, this resistor being electrically connected in series between the first arcing contact and the first contact of permanent current, characterized in that the resistor insertion system comprises two auxiliary contacts, the first of which (7B) is electrically connected to the first permanent current contact and the second (7A) of which is connected to the first co arc contact, in that these two auxiliary contacts are mounted movable relative to each other in the longitudinal direction so as to be able to approach one another, when the switch, to establish a connection which short-circuits the resistor and so as to be integral in displacement in the longitudinal direction, when the switch is closed, before establishing said connection which short-circuits the resistor. The switch according to claim 1, in which the first arcing contact has the shape of a rod on which slides a metal block (5) carrying the second auxiliary contact and in which this block is pushed according to the longitudinal direction, when closing the switch, by a nozzle (2D) integral with the second arcing contact. The switch according to claim 2, in which the block (5) having one end substantially conical which fits into the nozzle (2D). The switch according to claim 2, in which block has a tubular extension (5C) which extends in the longitudinal direction and on which slides an insulating piece (13) integral with the first auxiliary contact, the tubular extension having a end forming a piston (5D) which cooperates with a recess (13A) in the insulating part so that the piston is made integral with the insulating part, during the closing of the switch, by the play of a depression created in the recess of the insulating part between the piston and the insulating part. The switch according to claim 2, in which the block (5) comprises an internal chamber (10) which is divided by a radial shoulder (11) of the rod of the first arcing contact, and in which a spring (12) is placed in the chamber against the radial shoulder of the rod such way that the displacement of the block along the rod of the first arcing contact, when closing the switch, causes the compression of the spring at the same while the chamber is filling with gas and when opening the switch, the spring relaxing exerts a restoring force which tends to move automatically block in reverse with the gases are evacuated from the chamber through an orifice (5B) of this, the orifice being further calibrated so that it is exerted resistance against the spring return force. The switch according to claim 1, in which the first auxiliary contact (7B) and the first permanent current contact (3A) are integral with a movable tube (8) in the longitudinal direction, in in which a spring (15) is arranged against the tube movable (8) to oppose the movement of this next tube the longitudinal direction, when closing the switch, this spring exerting a restoring force during of the switch opening which tends to move automatically the tube in said longitudinal direction and in a contrary direction.

Images