FR2459543A1 - HIGH VOLTAGE CIRCUIT BREAKER WITH ROTATING ARC AND SELF-BLOWING - Google Patents

Abstract

The circuit breaker comprises a fixed main contact (13), a moving main contact (11) and, branched-off, an auxiliary cutout circuit including an electromagnetic blast coil (21) connected to an axisymmetric electrode (24) arranged concentrically inside the coil and a moving contact. This arc contact consists, on the one hand, of a semi-mobile contact (16) whose side walls cooperate with the said axisymmetric electrode (24) in order to give rise, during the throwing open of the circuit breaker, to a first rotating arc (28) and maintain it in the central part of the coil (21) and, on the other hand, of a moving contact (14) arranged in the extension of the semi-mobile contact (16) and solid with a member for throwing the circuit breaker. The free end of the semi-mobile contact cooperates with the free end of the moving contact in order to give rise, when they separate, to a second arc (30) located in series with the said first rotating arc and perpendicular to it. These arcs are generated in an arc chamber (27) having an orifice (50) for ejecting gases under the pressure developed by the said arcs, the said orifice being arranged square with the second arc and allowing the blasting thereof, during the withdrawal of the moving contact from the chamber through the said orifice.

Description

 The invention relates to a high voltage circuit breaker with rotating arc and self-bleeding in a gas with high extinguishing power, such as, for example, sulfur hexafluoride, or a mixture of SFg and nitrogen.

This type of circuit breaker for which the rotating arc is aroused by the electromagnetic field of a coil, has the advantage of requiring only a low operating energy.

Such an apparatus has been described in patent application No. 78 10481.

However, its use in very high voltage generally requires the placing in series of several cut-off members and therefore of several coils, which leads to a bulky and consequently expensive device.

The object of the invention is a rotary arc circuit breaker allowing a higher cut-off voltage with a single coil.

The subject of the invention is a high voltage circuit breaker under a dielectric gas enclosure comprising, bypassing between a fixed main contact and a movable main contact, an auxiliary breaking circuit comprising an electromagnetic blowing coil connected to a revolution electrode disposed concentrically with the interior of said coil in its central part to give rise in cooperation with a movable arcing contact disposed in the axis of the electrode to a rotating arc, characterized in that the movable arcing contact consists of on the one hand by a semi-mobile contact whose side walls cooperate with said electrode of revolution to give rise, during the opening operation of the circuit breaker, to a first rotating arc and to maintain it in this central part and on the other hand by a movable contact disposed in its extension and integral with a circuit breaker operating member, the free end of the semi-mobile contact cooperating with the end é free from movable contact to give rise, when separated, to a second arc placed in series with said first rotating arc and perpendicular to it, said arcs being generated in an arc chamber having a gas ejection orifice the pressure developed by said arcs, said orifice being disposed in line with the second arc and allowing it to be blown, when the movable contact is removed from the chamber through said orifice.

According to one characteristic, at least one of the semi-mobile and mobile contacts is tubular and passes through the arc chamber. Said tubular contact has an orifice for discharging compressed gases under the effect of arcs, said orifice being disposed outside the arc chamber.

According to another characteristic, the walls of the arc chamber are produced by the blowing coil and on one side of the coil by an insulating plate traversed by the semi-mobile contact and on the other side by an insulating nozzle supporting said orifice evacuation gas crossed in the closed position of the circuit breaker by the movable contact.

 According to one arrangement, the electrode of revolution comprises a first ring disposed in sliding contact with the semi-mobile contact, in the closed position of the circuit breaker and a second ring of larger diameter arranged on the side of the mobile contact. The distance from the center of the second ring to the gas discharge orifice is between 1.5 and 2.5 times the inside diameter of the second ring.

According to another arrangement, the circuit breaker comprises a closing resistor disposed between the end of the semi-mobile contact opposite the mobile contact and the fixed main contact.

 According to another embodiment, the main movable contact comprises two positions for driving by a circuit breaker operating member, said member sliding on a piston secured to the mobile contact, the first position corresponding to the start of the opening maneuver and to the end of the closing maneuver, the second position corresponding to the end of the opening maneuver and the start of the closing maneuver. During the closing operation, the movable main contact is brought into closure on the fixed main contact before the semi-movable contact, pushed back by the movable contact, comes into contact with the revolution electrode.

 The dielectric gas used can be a mixture of sulfur hexafluoride and nitrogen.

The characteristics and advantages of the invention will appear in the description given below with regard to the embodiments given by way of example and illustrated in the drawings.

Figure 1 is a schematic view in axial section of a circuit breaker according to the invention in the closed position.

 Figure 2 is a view of the circuit breaker according to Figure 1 during the opening operation.

Figure 3 is a view of the circuit breaker according to Figure 1 in the open position.

 FIG. 4 is a schematic view in axial section of an alternative embodiment of the circuit breaker according to FIG. 1.

Figure 5 is a schematic view in axial section of an alternative embodiment of the circuit breaker comprising a closing resistor.

Figure 6 is a schematic view in axial section of another alternative embodiment of the circuit breaker according to the invention in the closed position.

 Figures 7 to 9 show a sequence of half-section views of the circuit breaker according to Figure 6 corresponding to various successive positions occupied during the opening operation.

Figure 10 shows the circuit breaker of Figure 6 in the intermediate position during the closing operation.

In Figure 1, there is shown a circuit breaker in a sealed enclosure 31 of gas with high extinguishing power, such as sulfur hexafluoride, under a pressure of a few bars. This enclosure comprises from bottom to top an insulator 1 overall support, a ferrule 8, an insulator 11, a ferrule 5 and a conductive cover 6 forming the upper part. The lower part under the insulator is closed by a plate 7.

The ferrule 8 supports a terminal 2 of the circuit breaker and a crown of contact fingers 12. The ferrule 5 supports the other terminal 3 of the circuit breaker and a crown of contact fingers 13 constituting the fixed main contact.

 The movable main contact is constituted by a cylinder 11 whose lower end 33 slides on the ring of contact fingers 12 and whose upper end 35 cooperates in the closed position with the ring of fixed contact fingers 13. The cylinder 11 is connected by arms to a movable contact rod 14 secured to an insulating operating rod 9 passing through the plate 7 and driven by a device not shown.

The end of the movable contact 14 is tubular and has laterally orifices 15 through which blowing gases can escape into the enclosure 31. At the end of the movable contact 14 is arranged in cooperation a semi-movable arcing contact 16 entirely tubular and comprising, as an extension following a first cylindrical zone 116, a conical zone 17 and a second constricted cylindrical zone 18 disposed at the upper part and having an orifice 19 allowing the blowing gases to escape.

The semi-movable arcing contact is recalled by a spring 20 which is supported on the cover 6 by means of an insulating cup.

 An insulating nozzle 25 fixed and supported by a shoulder 26 of the shell 5 is arranged concentrically around the movable contact 14 through a neck constituting an orifice 50. The nozzle 25 supports a blowing coil 21, embedded in an insulator, the inlet is connected by an annular plate 22 from the base of the cover 6 to the fixed main contact ring 13 through the ferrule 8 and the outlet of which is connected to a revolution electrode 24 arranged concentrically around the first cylindrical region of the semi contact -mobile 16 and at the level of the central part of the coil 21. The nozzle 25, the coil 21 and an insulating plate 23 disposed at the upper part and traversed by the semi-mobile contact 16, delimit an arc chamber 27 traversed axially by the movable arcing contact, formed by the semi-movable contact 16 and the movable contact 14, the inside diameter of the nozzle 25 being only very slightly greater than the outside diameter of the movable contact 14. The electrode e of revolution 24 is double and comprises a first upper ring 124 slidingly arranged around the first cylindrical zone 116 and a second lower ring 224 of larger diameter.

The operation of the device is as follows. In the closed position of FIG. 1, the current flows through terminal 3, the fingers of the fixed main contact 13, the cylinder 11, the contact fingers t2 and terminal 2, the current passing through the coil 21 being negligible because of its high reactance. At the start of the opening maneuver, the rod 9 moves downwards. The arcing contact 16 pushed by the spring 20 follows the arcing contact 14. The cylinder 11 separates from the fingers of the fixed main contact 13. The current then passes through the terminal 3, the ferrule 5, the annular plate 22, the coil 21, the crown 124, the semi-mobile contact 16, the mobile contact 14, the arms 10, the cylinder 11, the contact fingers 12 and the terminal 2, because the arc which may have arisen between the end 35 of the cylinder and the crown of the contact fingers 13 is shunted by the coil 21 and goes out in the gas existing in the enclosure 31. The current then passing through the coil 21 and the rod 9 continuing to move downwards , the first cylindrical zone 116 of the semi-mobile arcing contact 16 passes below the ring 24 which is located successively at the height of the conical part 17, then of the cylindrical part of reduced diameter 18.

An arc 28, coming from the crown 124, passes successively from the zone 17 then to the zone 18 as it is represented in the intermediate open position of FIG. 2. The arc 28 is subjected first to the force created by the electromagnetic field of the coil 21 and -turns to rotate.

The downward movement of the movable contact 14 causes its separation from the semi-movable contact 16, the upper end of which comprises a shoulder 52 which abuts against the insulating plate 23. This separation accompanied by the displacement of the movable contact 14 creates a suction of the rotating arc 28 downwards and its substitution by another rotating arc 29 of greater length between the second lower ring 224 and the semi-mobile contact 16. But simultaneously the separation of the semi-mobile 16 and mobile 14 contacts gives rise to a second arc 30 which is in series with the rotating arc 28, then 29 and perpendicular to them.

The arcs 29 and 30 rapidly increase the pressure of the gas in the chamber 27.

The compressed gas first exerts a moderate blowing of the arc 30 through the orifices 19 and 15, then a vigorous blowing through the orifice 50 at the time of the opening of the movable contact 14 out of the chamber 27, which causes its extinction simultaneously with that of the rotating arc 29. A suitable distance between the rotating arc 29 and the orifice 50 makes it possible to reduce the influence of the ionized gases due to the rotating arc 28 then 29. A distance from the order of 1.5 to 2.5 times the internal diameter of the crown 224 may be sufficient.

At the end of travel of the rod 9, the end 33 of the cylinder 11 abuts on a shoulder 34 of the ferrule 8 and the circuit breaker is in the open position of FIG. 3. The movable arcing contact 14 and the semi-mobile arcing contact 16 are located on either side of the blowing nozzle 25 and the voltage is applied directly in series in the insulating gas at the terminals of the circuit breaker, between the electrode 24 and the semi contact -mobile 16 on the one hand and the semi-mobile contact 16 and the mobile contact 14 on the other hand.

 When closing, the apparatus passes from the open position of FIG. 3 to the intermediate closed position which corresponds to FIG. 2, then to the closed position of FIG. 1. Between the positions of FIGS. 2 and 1, when the arcing contact 14 repels the semi-mobile contact 16 and the conical surface 17 approaches the crown 124, the coil 21 is inserted into the circuit until it is short-circuited by the coming into contact of the ring of fingers of the fixed main contact 13 with the end 35 of the cylinder 11. To reduce the stress in the coil 21, the closing speed of the operating rod 9 must be sufficient between the instant of the closing of the contacts between the semi-mobile contact 16 and the crown 124 and that of the closing of the contact of the cylinder 11 with the fixed main contact 13.

The variant embodiment of FIG. 4 relates to a circuit breaker, where the nominal current is moderately high, it is possible to use an isolator 4 of smaller dimensions. The crown of fixed main contact fingers 13 which is supported by the shoulder 26, is disposed around and below the orifice 50 and the tubular contact 14 supports below the orifices 15 a crown 111 cooperating with the fingers of the main contact 13 arranged under the shoulder 26. But at very high voltage, the closing of line circuit breakers is often preceded by the insertion into the circuit of a resistance of ohmic value close to the wave impedance of the line , then the short-circuiting of this resistor.

Figure 5 shows the adaptation of such a closing resistor on a circuit breaker, similar to that of Figures 1 to 3. The resistor 36 is disposed at the upper part of the arc chamber 27. It is suspended from the cover 6 and connected by a connection 37 bypassing the spring 20, to the upper part of the semi-mobile contact 16. During the closing operation, the upward movement of the rod 9 first causes the movable arcing contacts 14 to touch each other. and semi-mobile 16, which inserts the resistor 36, the circuit closing by the cover 6, the ferrule 5 and the terminal 3. The continuation of the movement of the rod 9 brings successively in contact firstly the conical area 17 with the crown 124 of the electrode 24, which causes the shunt of the resistor 36 by the coil 21 whose ohmic value is clearly lower, then the end 35 of the cylinder 11 with the ring of fingers of the main contact 13, this which shunts both resistor 36 and coil 21 before the end of the closing operation.

 The use of resistor 36 also has advantages for cutting. Indeed, the rotating arc being shunted by the resistor 36, when the current crosses to zero, it will very greatly reduce the voltage across the terminals of the first breaking interval between the electrode 24 and the movable contact 16, which will facilitate regeneration. dielectric and will make it easier to interrupt the current. The embodiment of Figures 6 to 10 ensures the insertion of the coil 21 during cutting like the device of Figures 1 to 3, but it avoids the insertion of the coil 21 during closing and eliminates the corresponding stresses in the coil.

In FIGS. 6 to 10, the movable arcing contact 14 has been shown in the form of a solid rod, but it can also have the tubular shape of the arcing contacts 14 in FIGS. 1 to 3. The movable contact 14 is connected to the operating rod 9 by a drive member 38 fixed on the rod 9 and constituted by a cylinder in which moves a piston 39 secured to the arcing contact 14. A good electrical contact is ensured between the cylinder 38 and the piston 39 by segment contacts for example. The displacement of the piston 39 in the cylinder 38 is limited to the lower part by the bottom 40 of the cylinder 38 and to the upper part by a stop 41. A spring 42 tends to push the piston 39 towards the stop 41. The member d entrainment 38 can be secured in two different positions inside a movable cylinder 43 constituting the main contact by means of a latch device, produced for example using balls such as 44 pushed by a return spring and cooperating with two notches 45 and 46 arranged inside the cylinder 43. The electrical connection between the drive member 38 and the movable cylinder 43 is produced using a sliding contact 47. The stroke of the movable member 43 is limited to the lower part by the entry into contact of its end 33 with the fixed opening stop 34 and to the upper part by the entry into contact of its end 35 with the fixed closing stop 48.

 In the closed position, the circuit breaker is in the position of FIG. 6. At the start of the opening, the rod 9 does not cause the movable contact 14 and the piston 39, which slides in the cylinder 38 while the spring 42 relaxes, but the rod 9 drives the member 43 secured to the cylinder 38 by the ball 44 in the notch 45. This operation separates the main contacts 13 and 35. Then the stop 41 driving the piston 39, as shown in the Figure 7, the movable contact 14 moves with the rod 9. The cut is made as for the circuit breaker of Figures 1 and 3, except that there is no blowing through the full movable contact 14 and that a tubular partition 49 disposed in the cover 6 reduces its volume, which reinforces the blowing in the nozzle 25 on the arc 30, as shown in FIG. 8. In this figure, where the lower end 33 of the cylinder 43 has arrived at the opening stop 34, the movement of the rod 9 and of the cylinder 38 moves the ball 44 by the notch 45 to the notch 46, and, by the stop 41, brings the contact 14 to the fully open position in FIG. 9.

 When closing, as shown in FIG. 10, the upward movement of the rod 9 drives the member 38 and the cylinder 32 secured by the ball 44 in the notch 46 and ensures the end contact of the cylinder 43 with the ring of fingers 13 of the main fixed contact before the ring 124 comes into contact with the conical zone 17.

 The coil 21 is then short-circuited by the cylinder 43, which prevents it from being inserted into the circuit during closing. Continued movement of the rod 9 successively brings the end 35 of the cylinder 43 into contact with the closing stop 48, then the movement of the ball 44 from the notch 46 to the notch 45, the closure between the movable contact 14 and the semi-movable contact 16, the compression of the springs 42 and 20 and the upward movement of the semi-movable arcing contact 16. The device thus passes into the closed position of the figure 6.

 The advantages of the devices according to the invention are as follows - these devices make it possible to obtain large arc distances with a single coil, - the appearance and the development of the arc intended to increase the blowing pressure in a chamber located inside the coil allows rapid elongation of the arc subjected to a high field, allowing a high speed of rotation of the arc, hence rapid heating of the gas, low wear of the electrodes, less gas ionized; - the use of a relatively reduced compression space allows a rapid increase in pressure, - the displacement and the elongation of the arc are facilitated by the combined action of the electromagnetic field of the coil and the aspiration of the arc by the movement of the movable rod at the time of blowing, - the use for the main insulation between contacts in the open position of the cut-off gap located in the direction of movement of the movable contact allows the isolation with a single movement of the insulating operating rod 9, which simplifies the mechanism, - the use of a fixed insulating blowing nozzle mounted on one end of the coil simplifies construction, - the use of large conductors relatively short section and length 11 or 43 connecting directly in the closed position of the contacts 12 and 13 which can easily include a large number of fingers allows a large nominal current in steady state, - the use of two arcs in series such as 29 and 30 greatly improves the cut-off, - blowing through the orifices of the tubular contacts and of the nozzle facilitates and accelerates the extinction of the arc.

 The variant embodiment of FIG. 4 shows that it is easy to adapt a resistance to the device for closing the vacuum lines.

In addition, the arrangement of this resistance facilitates the extinction of the arc during cutting.

A rapid closure avoids the passage of the peak of the current in the coil and reduces the stresses in the latter in the device of FIG. 1. The drive device of the alternative embodiment of FIGS. 6 to 10 avoids the insertion of the coil, therefore all the corresponding constraints, during closing and simplifies the coil. It also makes it possible to reduce the closing speed and the no-load opening speed.

When the breaking current increases, the heating and the pressure in the arc chamber 27 and in the volume reduced by the tubular partition 49 increase rapidly and the high pressure accelerates the movement of the rod 9 whose movable arcing contact 14 fully closes the orifice 50 of the nozzle 25 practically until the instant corresponding to the position of FIG. 8.

At this time, the pressure and the blowing are very important and quickly extinguish the arc. This gives an increase in the pressure and the tripping speed as a function of the current to be cut.

All the interrupting chambers according to the invention allow the use in series of two identical chambers arranged horizontally or in a V, supported by a vertical insulator containing the operating linkage and the control mechanism and constituting the vertical part of the T or l 'y.

 Furthermore, the dielectric saz used can be a mixture of sulfur hexafluoride and nitrogen in a proportion of 20 to 80 P.

 It is obvious that the invention is in no way limited to the embodiments which have just been described and represented and which have been given only by way of examples; in particular, it is possible, without departing from the scope of the invention, to modify certain provisions or replace certain means with equivalent means, or else replace certain elements with others capable of ensuring the same technical function or a technical function equivalent.

Claims (10)

1 / High voltage circuit breaker under a dielectric gas enclosure comprising, in bypass between a fixed main contact and a movable main contact, an auxiliary breaking circuit comprising an electromagnetic blowing coil connected to a revolution electrode disposed concentrically inside said coil in its central part to give rise in cooperation with a movable arcing contact arranged in the axis of the electrode to a rotating arc, characterized in that the movable arcing contact consists firstly of a contact semi-mobile (16) whose side walls cooperate with said revolution electrode (24) to give rise, during the opening operation of the circuit breaker, to a first rotating arc (28) and maintain it in this central part and d 'other hand by a movable contact (14) disposed in its extension and integral with a circuit breaker operating member, the free end of the semi-mobile contact cooperating with the lib end re of the movable contact to give rise during their separation to a second arc (30) placed in series with said first rotating arc and perpendicular thereto, said arcs being generated in an arc chamber (27) having an orifice ( 50) for ejecting the gases under the pressure developed by said arcs, said orifice being arranged in line with the second arc and allowing it to be blown, when the movable contact is removed from the chamber through said orifice. 2 / A circuit breaker according to claim 1, characterized in that at least one of the semi-mobile (16) and mobile (14) contacts is tubular and passes through the arc chamber (27). 3 / A circuit breaker according to claim 2, characterized in that a tubular contact has an outlet orifice (19, 15) for gases compressed under the effect of arcs, said orifice being disposed outside the arcing chamber ( 27). 4 / Circuit breaker according to one of claims 1 to 3, characterized in that the walls of the arc chamber (27) are formed by the blowing coil (21) and on one side of the coil by an insulating plate (23) traversed by the semi-mobile contact and on the other side by an insulating nozzle (25) supporting said orifice (50) for evacuating gases traversed in the closed position of the circuit breaker by the mobile contact (14). 5 / Circuit breaker according to one of claims 1 to 4, characterized in that the revolution electrode (24) comprises a first ring (124) disposed in sliding contact with the semi-mobile contact, in the closed position of the circuit breaker and a second ring (224) of larger diameter disposed on the side of the movable contact (14). 6 / A circuit breaker according to claim 5, characterized in that the distance from the center of the second ring (224) to the orifice (50) for discharging the gases is between 1.5 and 2.5 times the internal diameter of said crown. 7 / Circuit breaker according to one of claims 1 to 6, characterized in that it comprises a closing resistor (36) disposed between the end of the semi-mobile contact (16) opposite to the mobile contact and the fixed main contact ( 13). 8 / Circuit breaker according to one of claims 1 to 7, characterized in that the main movable contact (43) comprises two positions of drive by an operating member (38) of the circuit breaker, said member sliding on a piston (39) secured to the movable contact (14), the first position (45) corresponding to the start of the opening maneuver and to the end of the closing maneuver, the second position (46) corresponding to the end of the opening maneuver and at the start of the closing operation. 9 / A circuit breaker according to claim 8, characterized in that during the closing operation the movable main contact (43) is brought into closure on the fixed main contact (13) before the semi-movable contact (16), repelled by the movable contact (14) does not come into contact with the revolution electrode (24). 10 / Circuit breaker according to one of claims 1 to 10, characterized in that the dielectric gas used is a mixture of sulfur hexafluoride and nitrogen.