EP2943967B1 - Disconnecting switch with rotating arc contact - Google Patents

Description

TECHNICAL AREA

The present invention relates to the field of electrical switchgear, in particular the disconnector or earthing switch type, preferably high voltage. Even more preferentially, the invention relates to a high-voltage disconnector of the GIS (gas insulated switchgear) type, that is to say located in a metal or shielded casing with electrical insulation conferred by gas. SF6 or equivalent.

STATE OF THE PRIOR ART

Conventionally and in a manner known to those skilled in the art, an electrical switchgear of the disconnector or earthing switch type comprises an electrically conductive assembly which is moved at a constant translational speed during each opening operation and during each closing operation.

During these repeated operations, the conductor assembly, which is generally equipped with a permanent contact and an arcing contact, undergoes mechanical and electrical stresses that gradually generate its degradation. This phenomenon is also observed on the other permanent contact and on the other arcing contact of the apparatus, said fixed contacts.

These problems generate the creation of particles, pollution, heating, and affect the life of the electrical equipment.

In particular, during an opening operation, if the speed of the electrically conductive assembly is too fast, it causes mechanical wear of the permanent contacts. This could be an incentive to reduce the speed of the electrically conductive assembly, but in return there would be an electrical wear of the arcing contacts, due to the formation of an electric arc between them during the opening operations, especially in case of busbar transfer.

In an attempt to solve this problem, the document FR 2 547 107 proposes an electrical apparatus with a fixed arc contact coupled to a spring, which makes it possible to accelerate the spacing speed of the two arcing contacts at the time of their separation. Nevertheless, the fixed arcing contact can no longer really be regarded as fixed, since it is slidably mounted on the fixed frame of the apparatus. On the other hand, conventional designs of switchgear usually do not monitor the area of the fixed contact, so that the detection of a possible anomaly on the spring is not possible. This seems unacceptable, as a failure of the undetected spring would cause a dangerous malfunction of the switchgear. Such electrical switchgear is also known from the document EP 1 760 743 .

In addition, the presence of permanent magnets to operate the system is likely to generate electromagnetic disturbances which are of course not desirable.

Finally, the coupling of the spring to the fixed contact requires a significant increase in the size of the area, which results in an increase penalizing the overall size of the electrical switchgear, which is nevertheless a criterion considered essential on the current equipment.

There is therefore a need for optimization of these switchgear devices, in particular to reduce the adverse effects associated with the formation of arcing between arcing contacts during opening operations.

STATEMENT OF THE INVENTION

The invention therefore aims to at least partially overcome the disadvantages mentioned above, relating to the achievements of the prior art.

To do this, the subject of the invention is an electrical switchgear, in particular a disconnector, according to claim 1.

The proposed solution is first advantageous in that it allows, by relative rotation of the two arcing contacts, to stretch the electric arc occurring between them during an opening operation. This stretch promotes the extinction of the arc, and also distributes the electrical wear on these arcing contacts. The adverse effects of repeated arc flash formation between the arcing contacts are therefore largely attenuated, and the lifetime of these contacts is advantageously improved.

In addition, the invention is remarkable in that it makes it possible to vary the speed of said arcing contact of the moving assembly, during the same opening operation, by means of the acceleration caused by the release of energy from the elastic return means. Consequently, this controlled variation can be determined in such a way as to best limit the mechanical and electrical wear of the electrically conductive assembly. In this respect, the release of energy is preferentially initiated after the separation of the permanent contacts, and during the separation of the arcing contacts, that is to say initiated at the precise moment of the separation of the contacts. arcs or before that moment, and completed after they are separated. As a result, the speed of the moving arc contact embossed on the electrically conductive assembly is even higher during this critical phase of the opening operation, which limits the damage due to electrical stresses. Of course, this improvement is added to that described above, conferred by the rotational nature of the moving arc contact.

This feature of the invention is also advantageous in that it allows a variation of the speed of said arc contact of the moving assembly, while moving at a constant speed of translation the point of attachment of a device of the invention. training of the mobile unit electrically conductive. Consequently, this drive device can advantageously incorporate a motor driven at constant speed, even if a variable speed could be implemented, without departing from the scope of the invention.

Moreover, contrary to the solution described in the document FR 2 547 107 , the acceleration spring is not arranged on the side of the fixed elements, but on the assembly comprising the movable electrodes. Thus, by retaining this specific location, it is possible to overcome the problem of detecting a possible anomaly on the spring, as encountered in the prior art. It is indeed much easier to monitor a possible breakage of the spring when it is on the moving mobile assembly, than when it is close to the fixed elements. In addition, no permanent magnet is required as in the solution of the document FR 2 547 107 .

Finally, this preferred solution makes it possible to reduce the overall size of the apparatus compared to those encountered in the prior art. Indeed, in the prior art, the modification made to the fixed contact to make it slightly mobile causes a significant increase in the dimensioning, especially for purposes of translational guidance of this contact. On the other hand, when the accelerated element is arranged on the side of the moving electrodes / conductors, on the conductive assembly, the impact on the dimensioning is much smaller because this assembly already has a bulk important, including a significant length to ensure its guidance in translation.

By way of example, with the aid of the aforementioned elastic means, during the initial phase of an opening operation, the speed of the electrically conductive assembly can be slow, until the separation of the permanent contacts in order to limit the mechanical wear of these, then rise to limit the electrical wear of the arcing contacts.

Preferably, said rotation means are designed to initiate the relative rotation of the two arcing contacts during the separation of the arcing contacts, ie initiated at the precise instant of the separation of the contacts. arcs or before that moment. In addition, the design of the apparatus is retained so that the rotation is stopped at a time following that of the extinction of the electric arc.

More generally, it is noted that this primer takes place preferably after the start of the opening operation, and that the rotation is stopped before the end of this same operation. Typically, the relative rotation takes place over a period corresponding to a few milliseconds over a total opening stroke duration of approximately 10s, and / or over a distance corresponding to one third of the total stroke of the moving assembly during the opening operation. In addition, preferably, the design of the apparatus is such that no rotation occurs during the closing operations.

Preferably, said rotation means are designed so that the relative angular position between the two arcing contacts differs between that adopted in a closed position of the arcing contacts, and that adopted in the position of closing of the cycle directly consecutive. This further distributes the electrical wear on the arcing contacts, the life of which is further improved. As an indication, the equipment may be designed so that the angular extent of the relative rotation after each cycle is such that 360 is not a multiple of the value of this extent. With such a principle, after a complete revolution of relative rotation between the arcing contacts, generally obtained after several cycles, the relative position between the two arcing contacts is not the same as that adopted at the beginning of the previous round. This angular extent is preferably identical to each cycle.

It is noted that the relative rotation between the arcing contacts can be obtained by rotating the two contacts, or only one of them, whether it is movable in translation or fixed. The preferred embodiments presented below, however, relate solely to the case of a single rotating mobile arcing contact, which is here the movable translational arc contact.

Preferably, said elastic return means comprise at least one compression or traction spring.

Preferably, said rotation means are designed to apply a relative rotation of the two arcing contacts only during the energy release phase of said elastic return means, and even more preferably during a very large part of this phase of release of energy.

Preferably, said other body of the electrically conductive assembly is intended to be connected to a point of attachment of a driving device of said movable electrically conductive assembly.

Preferably, said other body comprises the permanent electrical contact.

Preferably, said rotating means comprise a finger system housed in a helical groove, said relative rotation of the two arcing contacts operating automatically by moving the finger in the helical groove, during sliding between said other body and the movable arcing contact, during the energy release phase of said elastic return means. Thus, this principle provides a simple and effective solution for converting the sliding motion of the moving arc contact into a helical motion, including the desired rotation of the arc contact. This principle of finger and helical groove, or the like, is moreover applicable even when the apparatus does not have a system enabling the acceleration of the moving arcing contact.

Preferably, said system also comprises a ring surrounding the movable arcing contact, said ring being integral with the end of the finger opposite to that housed in said groove made in said other body.

Preferably, said ring is connected to the movable arcing contact so that when it is rotated in a first direction of rotation, it carries with it the arcing contact in rotation along the central axis, and so that when it is rotated in a second direction of rotation opposite to the first, it causes no rotation of the arc contact.

Preferably, the apparatus comprises abutment means making it possible, during an opening operation, to block the translational movement of said movable arcing contact with respect to a fixed body of the apparatus, and said other body is provided with unlocking means adapted to release said abutment means after said other body has been moved relative to the movable arcing contact, by a predetermined distance.

Preferably, said abutment means comprise a first abutment integral with said movable arcing contact, as well as a second abutment mounted on said fixed body of the apparatus. In this case, it is preferable that said second stop is an integral part of a trigger pivotally mounted on said fixed body, the unlocking means of said other body being intended to rotate this trigger to release said first and second stops.

Finally, the subject of the invention is also a method for implementing an opening operation using an apparatus as described above, the process being such that at least after the separation of the two electrical arcing contacts, these are rotated relative to each other along their central axis.

Other advantages and features of the invention will become apparent in the detailed non-limiting description below.

BRIEF DESCRIPTION OF THE DRAWINGS

• les figures 1a à 5 représentent un sectionneur selon un mode de réalisation préféré de la présente invention, dans différentes configurations adoptées successivement au cours d'une opération d'ouverture.

This description will be made with reference to the appended drawings among which;

• the Figures 1a to 5 represent a disconnector according to a preferred embodiment of the present invention, in different configurations successively adopted during an opening operation.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

With reference first to figures 1a and 1b , there is shown a portion of a disconnector according to a preferred embodiment of the invention, this disconnect may be an earthing switch, preferably a high voltage disconnector type GIS.

The disconnector 1 comprises a cutoff chamber 2 shown only partially, enclosed in an enclosure containing an insulating gas such as SF6 gas or any other gaseous mixture deemed appropriate. The chamber 2 encloses a stationary permanent contact (not shown), as well as a fixed arcing contact 5a partially shown, intended to be located radially inwardly with respect to the permanent contact.

In addition, it contains an electrically conductive moving assembly 6, connected to a fixed body 8 in which it is movable in translation, in a direction of displacement represented by the arrow 11. This assembly 6 has an end equipped with a movable permanent contact 4b in the form of a tube, and also comprises a moving electric arc contact 5b arranged radially inwardly with respect to the permanent contact 4b. These two contacts 4b, 5b are intended to cooperate with the aforementioned fixed contacts.

The assembly 6 generally takes the form of a sliding cylinder, like the piston of a jack, in a cylindrical housing 10 of the body 8. The permanent contact 4b forms the outer body of the assembly, and is extended by a conductive cylinder 13 of smaller diameter through which the arc contact 5b also passes.

It is inside this rear cylinder 13 of the permanent contact 4b is practiced a through bore 12 oriented in the direction 11, and slidingly housing the arc contact 5b. Thus, the latter is slidably mounted relative to the permanent contact in the direction of movement 11.

In addition, the electrically conductive assembly 6 comprises elastic return means, such as a compression spring 16, forcing the contact 5b arc to move towards a first end position relative to the permanent contact 5b, corresponding to the position in which it is located at most in the cylinders of the permanent contact 4b, as shown on the figures 1a and 1b . This first position, towards which the spring 16 tends to push the arc contact 5b, thus corresponds to a position in which this contact is in the bottom of the opening bore 12.

To do this, the spring 16 disposed around the arc contact 5b is supported at one of its ends on a flange 18 of this contact, and is supported at the other of its ends on a ring 20 fixedly mounted in the boring opening 12 of the cylinder 13. More specifically, the flange 18 is formed on a support 15 of the arc contact 5b carrying the rod 17 of the same contact. The support is cylindrical with a diameter substantially identical to that of the bore 12, so as to allow the translational guidance of the entire arc contact 5b in the cylinder 13 of the permanent contact 4b. In addition, this support 15 linearly guides freely allowing the contact rod 17 to pivot, along the central axis 19 of the arc contacts also corresponding to the central axis of the assembly of this disconnector.

Thus, when the permanent contact 4b moves in the direction 11 in the direction of opening, leading to the separation of the electrical contacts, it transmits this movement to the arc contact 5b through the reaction of the compression spring 16 on the ring 20. Conversely, when the 4b permanent contact moves in the direction of closing direction in the direction 11, leading to a closer electrical contacts, it transmits this movement to the arc contact 5b by pressing its end into the bottom of the bore 12, or through the support of rods in the corresponding groove bottom, as shown on the figure 1a . Indeed, the arc contact holder 15 fixedly supports two diametrically opposed rods 21, at the end of each of which is placed a roller 23 forming a stop. The rods 21 pass respectively through the grooves 25 formed through the cylinder 13 of the permanent contact 4b, along the direction 11. In the closed position shown on FIG. figure 1a , as well as during the entire closing operation which precedes obtaining this position, the rods 21 are supported in the bottom of the grooves 25, thus allowing the translation drive 5b of the contact by the contact 4b.

In this respect, in order to put the permanent contact 4b in motion, in order to implement the opening and closing operations of the disconnector, this contact is connected at its rear end to an attachment point 22 of a device. 30. This device 30 schematized on the figure 1b can be realized conventionally, for example so as to apply a constant translation speed at the point of attachment 22, in the direction 11, during each closing operation and each opening operation.

The disconnector is also equipped with a trigger 34 pivotally mounted on the fixed body 8, along an axis of articulation 36 orthogonal to the axis 19. At its end opposite the articulation, the trigger has two stops 38. They form stop means jointly with the rollers 23, the latter constituting the first stops, and the abutments 38 forming second stops. To do this, the abutments 23, 38 are opposite and aligned in pairs in the direction 11. In the configuration shown in FIG. figure 1a the stops are at a distance from each other, and do not cooperate with each other. However, as will be detailed below, these stops are caused to temporarily cooperate in pairs during a specific phase of the opening operation, before a bead 40 provided on the rear end of the cylinder 13 does not rotate the trigger 34 by relying on a bar 42 thereof, thereby to release the first and second stops 23, 38. The bead 40 therefore performs a function of unlocking the stop means.

In the vicinity of the diameter break 44 between the front cylinder and the rear cylinder 13 of the permanent contact 4b, the disconnector is equipped with a system 50 allowing automatic and controlled rotation of the arc contact 5b, and more precisely of its rod. 17 according to the axis 19. The system 50 comprises firstly a ring 52 integral in translation with the rod 17 which it surrounds. In addition, it is integral in rotation of the same rod, but only in one of the two directions of rotation. Therefore, in a first direction of rotation of the ring 52 along the axis 19, this ring carries with it the arc contact rod, while in the other direction of rotation, the ring 52 rotates but the rod 17 remains fixed in rotation.

The ring 52 centered on the axis 19 fixedly bears a finger 54 oriented radially, whose free end, opposite to that integral with the ring 52, is housed in a helical groove 56 of axis 19 formed through the cylinder 13. This groove 56 is initiated at the diameter break 44, and extends rearwardly then being slightly extended by a small straight portion parallel to the direction 11.

On the figures 1a and 1b , the disconnector 1 is shown in the closed position, in which the electrical contacts cooperate in pairs. In this position, as indicated above, the arc contact 5b is forced into the bottom of the cylinder 13 by the compression spring 16, which causes the front ends of the arc contact 5b and the permanent contact 4b to reach each other. locate substantially in the same plane orthogonal to the central axis 19.

Referring now to Figures 2a to 5 , there will be described an opening operation of the disconnector, initiated from the closed position shown on the figures 1a and 1b . This operation is carried out by the constant speed rotation of an input shaft (not shown) of the drive device 30 shown in FIG. figure 1b , and leading to a displacement in translation at speed constant of the permanent contact 4b during all this opening operation.

During the initial phase of the opening operation, the displacement of the attachment point 22, in the direction 11 in the opposite direction to that of the fixed contacts, simultaneously causes the permanent contact 4b and the arc contact 5b via the spring 16. During this initial phase, the linear speed of the moving elements is relatively slow and constant, which makes it possible to limit the mechanical wear of the disconnector.

After the separation of the permanent contacts, the stops 23, 38 come into contact in pairs and lead to blocking the translation movement of the arc contact 5b relative to the fixed body 8, while the translational movement of the permanent contact 4b is continued always under the action of the driving device. After the activation of the abutment means 23, 38, the spring 16 compresses strongly, because the arc contact 5b is thus temporarily locked in translation relative to the permanent contact 4b, as shown in FIG. figure 2a . The arc contact 5b therefore remains a motionless moment in translation, without being driven by the permanent contact 4b which continues its course.

Thus, this causes the spring 16 to store energy by moving the permanent contact 4b relative to the arc contact 5b toward a second end position opposite to the aforementioned first end position. The Figures 2a and 2b show the state of the disconnector with the spring 16 strongly compressed, and the arcing contacts still in contact.

During this phase of compression of the spring 16, the finger 54 moves within the groove 56, thereby causing the rotation of the ring 52 in the second direction of rotation, that is to say, the one not causing the rod 17 of the arc contact 5b. This rod 17 therefore remains rotationally fixed relative to the arc contact support 15.

At the end of the compression phase of the spring, the state represented on the figure 2a shows that the finger 54 is supported on the front end of the helical groove 56, and / or resting on the diameter break 44 of the permanent contact.

In this state, the arc contact 5b, largely protruding relative to the permanent contact as shown in FIG. figure 2b , adopts a second position reached after the permanent contact 4b has been moved by a determined distance relative to the contact 5b.

At this moment, the bead 40 of the cylinder 13 bears on the rod 42 of the trigger 34 and causes the latter to pivot about the axis 36, as has been illustrated on FIG. figure 3 . After a certain angle of pivoting of the trigger, the second stops 38 release the first stops 23, and make free arc contact 5b which is then moved at a very high speed in the direction 11, under the effect of the release of energy of the spring 16.

The high speed displacement of the arc contact 5b attenuates the electrical stresses. These are further weakened by the fact that during the relative displacement between the two contacts 4b, 5b, the finger 54 moves within the helical groove 56, thereby causing the ring 52 to rotate in the first direction rotation, that is to say the one driving the rod 17 of the arc contact 5b. The figure 4a shows a portion of the disconnector during the phase of movement of the finger 54 in the groove 56.

Due to the rotation of the rod 17 relative to the support 15 along the axis 19, there is created a relative rotational movement between the two arcing contacts, which stretches the electric arc and thus promotes its extinction.

The release of energy from the spring and the rotation of the arcing contact are performed simultaneously, preferably during the separation of the arcing contacts, that is, they are initiated at the precise instant of the separation of the contacts of arcs or before this same instant. The rotation is stopped slightly before the end of the energy release phase, and more precisely stopped when the finger 54 enters the straight extension of the groove 56, in the configuration shown in FIG. figure 4b . In this regard, it is noted that the disconnector 1 is designed so that at this moment of end of rotation, the electric arc is already off.

The acceleration phase of the arc contact 5b is observed until the moment when this contact comes into abutment in the bottom of the bore 12, and / or when the rods 21 come into abutment in the bottom of the straight grooves 25 of the cylinder 13.

After this contact bringing the two ends before contacts 4b, 5b in a same plane orthogonal to the axis 19, these two contacts are again driven substantially at the same linear speed by the drive device, until they stop in the open position shown on the figure 5 .

After this opening phase, the arc contact 5b has been moved in rotation relative to its initially occupied position in the closed position. The angular extent of this rotation is for example between 92 and 100 ° in the solution shown, and is more generally greater than a quarter turn. Therefore, since the next closing operation causes no rotation of the arc contact 5b, the latter is then returned to the closed position in an angular position distinct from that adopted in the previous cycle. In this regard, to further limit the effects of electrical wear, it is preferentially made so that 360 is not a multiple of this value of the angular extent, so that the same angular position is repeated not after an entire turn of the arc contact.

Claims (13)

1. Switchgear (1), in particular a disconnector, comprising two arcing contacts (5a, 5b) designed to be brought from a closed position to an open position during an opening operation, by relative movement in translation along a central axis (19) of said arcing contacts;

   the switchgear further comprising turning means (54, 56) serving to turn the arcing contacts (5a, 5b) relative to each other along said central axis (19), at least after the arcing contacts have separated during an opening operation, characterized in that one of the two arcing contacts (5b) is a movable arcing contact forming an integral part of an electrically conductive movable unit (6) also comprising another body (4b) mounted to move in sliding relative to the movable arcing contact (5b) along a movement axis (11) of said electrically conductive unit (6), said unit further comprising resilient return means (16) interposed between said movable arcing contact and said other body, and said switchgear being designed so that during an opening operation, said resilient return means (16) can initially store energy as a result of the relative movement between said movable arcing contact (5b) and said other body (4b), and can subsequently release the stored energy in order to cause said movable arcing contact (5b) to accelerate.
2. Switchgear according to claim 1, characterized in that said turning means (54, 56) are designed to initiate relative turning of the two arcing contacts (5a, 5b) during separation of the arcing contacts.
3. Switchgear according to claim 1 or claim 2, characterized in that said turning means (54, 56) are designed in such a manner that the relative angular position between the two arcing contacts (5a, 5b) differs between the angular position adopted in one closed position of the arcing contacts and the angular position adopted in the closed position of the immediately consecutive cycle.
4. Switchgear according to any of the preceding claims, characterized in that said turning means (54, 56) are designed to apply relative turning of the two arcing contacts (5a, 5b) only during a stage in which said resilient return means (16) are releasing energy.
5. Switchgear according to any of the preceding claims, characterized in that said other body (4b) is designed to be connected to a connection point (22) of a drive device (30) for driving said electrically conductive movable unit (6).
6. Switchgear according to any of the preceding claim, characterized in that said other body comprises a permanent electrical contact (4b).
7. Switchgear according to any of the preceding claims, characterized in that said turning means comprise a system of a pin (54) received in a helical slot (56), said relative turning of the two arcing contacts (5a, 5b) taking place automatically as a result of the pin (54) moving along in the helical slot (56) during sliding between said other body (4b) and the movable arcing contact (5b), in the stage in which said resilient return means (16) are releasing energy.
8. Switchgear according to claim 7, characterized in that said system also comprises a ring (52) surrounding the movable arcing contact (5b), said ring being secured to the end of the pin opposite from its end received in said helical slot (56) made in said other body (4b).
9. Switchgear according to claim 8, characterized in that said ring (52) is connected to the movable arcing contact (5b) so that when it is turned in a first direction of rotation, it entrains the arcing contact (5b) together therewith, in turning about a central axis (19), and so that when it is turned in a second direction of rotation opposite to the first, it does not entrain any turning of the arcing contact (5b).
10. Switchgear according any of the preceding claims, characterized in that it includes abutment means (23, 38) serving, during an opening operation, to block the movement in translation of said movable arcing contact (5b) relative to a stationary body (8) of the switchgear, and in that said other body (4b) has unlocking means (40) designed to release said abutment means after said other body has been moved through a predetermined distance relative to the movable arcing contact (5b).
11. Switchgear according to claim 10, characterized in that said abutment means include a first abutment (23) that is secured to said movable arcing contact (5b), as well as a second abutment (38) mounted on said stationary body (8) of the switchgear.
12. Switchgear according to claim 11, characterized in that said second abutment (38) forms an integral part of a trigger (34) mounted to pivot on said stationary body (8), the unlocking means (40) of said other body (4b) being designed to cause said trigger to pivot so as to free said first and second abutments (23, 38).
13. A method of implementing an opening operation by means of switchgear (1) according to any preceding claim, characterized in that, at least after the two arcing contacts (5a, 5b) have separated, said contacts are caused to turn relative to each other along their central axis (19).

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