EP1870916B1 - Cylindrical slot guide activation of a load-break disconnector switch - Google Patents

Abstract

The circuit breaker (1) has a cylindrical cam (40) for performing opening/closing sequence of a gas type switch (10), a sulfur hexafluoride type interruption switch (20) and a disconnecting switch (30). The cam has a wall in which recesses (42-1-42-3) are defined. The drive element controls one of contacts of the switches. The switches (10, 20, 30) have fixed contacts (12, 22, 32) and mobile contacts (14, 24, 34) respectively, manipulated by a single command connected to poles of the circuit breaker. Each mobile contact is actuated by using a synchronization and actuation device using the cam.

Description

TECHNICAL AREA

The invention relates to the field of electrical equipment equipping the energy evacuation devices of generators in power generation plants. The invention relates to the actuation of the different breaking elements so that the alternator circuit breakers are of simpler structure.

More particularly, the invention relates to an alternator circuit breaker coupled to a disconnector in which the different relative movements between contacts are made by means of a cylindrical cam to optimize the synchronization and the speed of separation between the contacts, while maintaining the compactness of the circuit breaker.

STATE OF THE PRIOR ART

At the output of the plant, for example for each alternator, a safety option is to have a circuit breaker to isolate the circuit before the transformer connected to a power line. This type of switchgear, under a voltage of the order of 15 kV to 36 kV, then performs the functions of passing strong permanent current (of the order of several thousand amperes) and breaking high fault current. (of the order of tens of thousands of amperes), while isolating the circuit.

In view of the current intensity present as nominal in the circuit, the cut is performed in two stages by two switches in parallel, one permitting the passage of permanent nominal current and the other ensuring the breaking of the current of short circuit, thus defining a "main circuit" and an "auxiliary circuit".

The main circuit switch contacts for these alternator circuit breakers are large enough to withstand high nominal currents without overheating, and they define a relatively large volume. The cut-off switch conventionally comprises a bulb of reduced dimensions, disposed inside this volume and comprising movable arcing contacts relative to each other, which in fact only support the breaking current of the breaker.

Usually, the main contacts first deviate and travel a sufficient distance before the current switches on the arcing contacts, which then open and cause the interruption of the current.

It is usual that the alternator circuit breaker is associated with a disconnector, which has no breaking capacity: it opens only when the circuit breaker is open and therefore when the current no longer passes through the circuit. It is known that the disconnector can be integrated in the circuit breaker central disconnector described for example in EP 0 877 405 .

The actuation of the various breaking elements of such a disconnecting circuit breaker must be performed in the aforementioned order, and optimizing the separation speeds. However, given the size and weight of all, all solutions can not be considered.

In particular, according to the state of the art, the actuation is done in the usual way ( EP 0 877 405 ) by means of levers with springs, which however pose the problem of the dimensioning of the latter, and especially of their fatigue and their deterioration in the long run.

Another option concerns the realization of rod guide systems (document EP 0 878 817 ), which are however very difficult to design and large size.

STATEMENT OF THE INVENTION

The object of the invention is to make the alternator circuit breakers more compact and simple to implement thanks to a new, single-controlled actuation system.

More particularly, the invention relates in one of its aspects to an alternator disconnect circuit breaker comprising a switching switch in parallel with a breaking switch, for example a vacuum chamber; each of the switches comprises a pair of movable contacts in translation relative to each other along a respective axis, thanks to actuating means. The circuit breaker further comprises a section switch, advantageously in series with the cutoff switch, which comprises a pair of movable contacts relative to each other, advantageously in translation, by means of actuating means.

Preferably, the three axes of displacement of the contacts are merged. Usually, only one contact of each pair is mobile, the other is fixed.

The actuating means of one or more of the switches can be coupled to the corresponding contact via a connecting rod, to allow a certain distance between the contacts.

The circuit breaker furthermore comprises synchronization means making it possible, during a break, to separate successively and in this order the contacts of the switching switch, then of the breaking switch and then of the disconnector; the synchronization means also make it possible to successively close the contacts in the reverse order. Closing the cut-off switch, particularly if it is a vacuum interrupter, at the end of the opening maneuver can be provided. Advantageously, the synchronization means are coupled to the actuating means and allow, by a single command, the implementation of each of the interrupts.

According to the invention, for purposes of compactness of the circuit breaker and simplicity of the control, the actuating and synchronizing means of at least the first and second switches comprise a cylindrical cam, that is to say a cylinder provided with lights cooperating with sliding elements for actuating the contacts. Preferably, the cylinder also actuates the disconnector. The cylinder is rotated by a suitable system, for example a transmission chain or a set of rods operated by lever.

The actuating and synchronizing lights comprise a helical part, whose winding direction depends on the direction of translation of the contact concerned, and whose slope depends on the relative separation speed of the contacts. To generate the latencies between the opening of the switch contacts, the helical portions of the lights are shifted relative to each other by the presence of portions of zero slope (i.e., extending around the cylinder orthogonal to the axis) or weak.

It is advantageous for the movable contact of at least one switch, or preferably of all the switches, to be actuated via a plurality of sliding elements distributed around its periphery, for example two diametrically opposed elements; these sliding elements can be coupled to the contact via rods whose one end is fixed to the contact and the other door the sliding element. Each sliding element cooperates with a corresponding light of the cylinder, the lights allowing the actuation of a single contact being of similar profile but offset on the periphery of the cylinder. If rods between sliding element and contact are present, it is preferred that the plurality of actuating rods of the same contact is coupled together by means of a part ensuring their geometric positions, for example a bar.

According to a preferred embodiment, the actuating means are guided in translation by the presence of lugs cooperating with rectilinear grooves located on the casing of the circuit breaker. In particular, the sliding elements are extended perpendicularly to the axis of movement by these lugs.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the invention will be better understood on reading the description which follows and with reference to the accompanying drawings, given by way of illustration and in no way limitative.

The figure 1 schematically illustrates the principle of breaking a circuit breaker according to the invention.

The Figures 2A and 2B show a preferred embodiment of the circuit breaker according to the invention, in fully open and fully closed positions.

The Figures 3A and 3B schematically illustrate two elements forming part of actuating means and synchronization according to the invention.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

The operating principle of a circuit breaker, and in particular of an alternator circuit breaker 1 according to the invention, is shown schematically in FIG. figure 1 , with a main circuit in which a current I ₀ near the nominal current I flows in operation, and an auxiliary circuit biased for the short-circuit cutoff.

For an alternator circuit breaker, the passage of a current I with a rated current greater than several thousand amperes requires the use on the main circuit of a switch 10 whose contacts are particularly conductive, for example copper ; their breaking capacity is however limited because of the generation of electric arcs. A second switch 20 is connected in parallel with the first 10 in order to perform the actual cutoff function, the opening of the first switch 10 actually switching the current I of the main circuit on this auxiliary circuit; the contacts of this second switch 20, for example tungsten, are of limited performance with respect to the passage of the rated current I, but have a high breaking capacity.

Thus, the functions of transmission of the permanent current and short circuit break are separated: in case of bias, the first switch 10 is first activated, the current I then completely passes through the auxiliary circuit and causes the opening the second switch 20 to obtain the cutoff function. In addition, a third switch 30 is then open: its function is mainly a safety function, its association on the auxiliary circuit to avoid a drop dielectric strength of the second switch 20 which could accidentally allow the passage of current in the associated branch.

To close such a circuit breaker, the order is inverted: the disconnector 30 is first closed, then the cut-off switch 20, and finally the first switch 10.

Each of the switches 10, 20, 30 comprises a pair of movable contacts with respect to each other; advantageously, the first contact 12, 22, 32 of each pair is fixed, and the second contact 14, 24, 34 is movable relative to the first.

In particular, the first switch 10 may be of the gas type; it can also, especially if the nominal current is very high, itself be a switching device comprising two switches in parallel with each other. Preferably, however, as illustrated in figures 2 , the first switch 10 is an air switch comprising a first fixed tubular contact 12 about an axis AA in which can be inserted a second tubular contact 14 as well.

The second switch 20 may be a gas circuit breaker SF ₆ type; preferably, since the current I - I ₀ passing through it is weak in normal operation, it is a vacuum interrupter: this makes it possible to avoid the use of hexafluoride sulfur, which increases ecological performance and reduces costs.

Finally, the third switch 30 may comprise a fixed contact 32 in which can be inserted another movable contact 34 along the axis AA of opening / closing, the rod type.

Preferably, the first and second switches 10, 20 are coaxial: this coaxiality of the electrical circuits is favorable for switching the current of the main circuit to the secondary circuit; the contacts of the two switches thus extend in the same longitudinal direction and are displaced in translation parallel to this direction AA. In the preferred embodiment, the contacts of the third switch 30 also move in translation and the three axes along which move the contacts 14, 24, 34 are merged.

The pole operation of the isolating circuit-breaker 1 is such that the operation of the contacts of each switch 10, 20, 30 is preferably provided by a single control linked to the poles by a synchronization kinematics to ensure the sequence of operation.

According to the invention, each movable contact 14, 24, 34 is actuated via an actuating and synchronizing device using a rotary cam system located in an envelope 5 of the circuit breaker 1. This solution makes it possible to determine the movement of each switch 10, 20, 30 in a coaxial construction that promotes compactness; of easy and robust design during the time, the cam system 40 is located in the existing circuit breaker 1, without increasing its size.

In particular, the actuating and synchronizing means comprise a cylinder 40, preferably of revolution about the translation axis AA of the contacts 14, 24, 34 of the circuit breaker 1.

On the wall of the cylinder 40 are machined lights 42, at least one light by contact to operate: a first light 42 ₁ controls the opening and / or closing movement of the first main switch 10, a second light 42 ₂ controls the opening and / or closing of the second secondary switch 20, and a third light 42 ₃ serves to actuate the section switch 30. The drawing of the lights 42 allows the synchronization of the movements, as well as the determination of the speeds relative translation.

The actuation of each of the switches is effected by means of an element 44 able to slide in the corresponding slot 42 of the cylinder 40 and fixedly secured to the contact. If the contact is remote from the cylinder 40, the sliding element 44 can be coupled to one end of a connecting rod 46 which is secured, by its other end, fixedly in contact; to allow a better readability, it is this last embodiment which is illustrated in figure 3A , but it should be understood that in the majority of cases and for reasons of compactness, connection rod 46 is absent and the sliding elements 44 are part of the contact to move.

Thus, during the rotation of the cylinder 40 (arrow R), according to the design of the light 42, the sliding element 44 moves in the light 42 and the contact, for example via the rod 46, is animated in translation (arrow T).

Preferably, the contact, the sliding elements 44 and / or the connecting rods 46 are located inside the rotary actuating and synchronizing cylinder 40: the profile of the slots 42 can thus be more accurate in view of the greater diameter of the 40 cylinder, which is also more robust.

In order to avoid any twisting force on the contact, and especially any parasitic rotation of a rod 46, preferably, the sliding element 44 itself is guided in translation, or the connecting rod 46 is guided longitudinally. Advantageously, the guiding is carried out by cooperation between a lug 48 secured to the sliding element 44 and / or the rod 46 and a groove 50 parallel to the axis of translation AA of the contact, for example located on the casing 5 of the In particular, the sliding element 44 in the lumen 42 of the cylinder 40 can be extended outwards by a lug 48 sliding in a groove 50 of the casing 5.

The actuating and synchronizing lights are designed to control the speed and timing characteristics between the movement of each of the switches 10, 20, 30.

For example, in a preferred illustrated example, the cylinder 40 is located between the first and second contacts 14, 24 which move in opposite directions, the disconnector 30 being driven in a similar motion to the first switch 10. A drawing of lights 42 is illustrated in figure 3B , in a rolled version of the cylinder 40.

The first light 42 ₁ of the cylinder 40 comprises an initial end portion 42 _1i which is helical in a first direction: upon actuation R of the cylinder 40, the first contact 14 of the first switch 10 is biased in translation for separation in order to to cut off the current as quickly as possible. The slope of the first light 42 ₁ depends on the relative speed T to be obtained as a function of the speed of rotation R printed on the cylinder 40 by its control means 52.

Once the contacts of the first switch 10 open, it is no longer necessary to actuate them, and advantageously, the first light 42 ₁ comprises a final end portion 42 _1f which is rectilinear, normal to the axis AA. It is also possible to provide a slower translation by a change of slope, or a reversal of movement ...

The second light 42 ₂ comprises an initial end portion 42 _2i that is not sloping but linear along a perimeter of the wall: for a first time after the actuation, the second switch 20 is not requested. ; on the contrary, it remains closed so that the current flows from the main circuit to the auxiliary circuit. Thanks to drawing of the initial end portion 42 _2i of the second light, the rotation of the cylinder 40 does not initially cause any translation of the sliding element 44 and thus the second contact 24.

Once the contacts of the first switch 10 are separated, it is important to open the secondary switch 20: after the initial end portion 42 _2i , the second light 42 ₂ is extended by a helical median portion 42 _2m , whose slope depends the relative speed of opening of the switch 20. In the _illustrated frame, the winding direction of the second light 42 _2m is opposite that of the initial end portion 42 _1i of the first light, the two contacts 14, 24 moving in the opposite direction; this is only illustrative. The length of the initial end portion of the second lumen 42 _2i depends on the latency time before the actuation of the second switch 20; preferably, the arc covered by the second initial end portion 42 _2i is smaller than that covered by the first initial end portion 42 _1i , a sufficient opening of the main switch 10 being just defined to allow the opening of the vacuum ampoule 20 without risk of priming. Moreover, in view of the dimensions in the case of a vacuum bulb 20, it is noted that the length of the middle portion 42 _2m of the light is very small, the separation distance of the contacts 22, 24 being restricted.

In the same way, the actuation of the third contact 34 is shifted relative to the displacement of the second contact 24: the third light 42 ₃ comprises a linear initial end portion 42 _3i longer than the initial end portion 42 _2i of the second light and the middle portion 42 _2m of this second light, determined to be greater than the corresponding distance at maximum arc time; it is possible, of course, to print a "slow" translation movement instead. A helical winding of the third light 42 _3f is then provided, in the winding direction of the first light 42 _2i for this embodiment where the disconnector 30 and the first switch 10 operate "in the same direction" even if the opposite would be the case. possible. Again, it is advantageous that the end end portion _42f of the second lumen is linear and that the contacts 22, 24 do not move (at least for a while) once the opening is reached.

By the choice of the slope of each winding 42 _1i , 42 _2m , 42 _3f , it is possible to adjust the speed of separation of the contacts without changing the speed of rotation of the cylinder 40: the control means can be simplified, and the rotational animation of the cylindrical cam 40 can be performed by any system 52 adapted, for example by insulating rods mounted on a lever, or by a system of drive chains.

By choosing the light profiles 42, it is further noted that the closing sequence is also respected.

It is possible to adapt the drawings to the desired sequences, and for example to provide openings in two steps, or to design more than two or three parts for each of the lights 42 ₁ , 42 ₂ , 42 ₃ . In particular, and as represented on the figure 3B in order to protect it, it is possible to close the vacuum interrupter 20 once the section has been completed. For this purpose, the so-called final end portion 42 _2f of the second lumen is in fact extended by a second median portion 42 _{2m '} , in a direction opposite to the middle portion 42 _2m , which makes it possible to close the contacts 22, 24 of the bulb; a second final linear part 42 _2f can also be provided.

In addition, cam control and synchronization may be selected to operate the first two switches 10, only if, for example, a "knife" disconnector 30 is selected.

According to an advantageous embodiment (illustrated in a particular configuration in figure 3A ), in order to balance the forces on a contact, two sliding elements 44, 44 'are fixed therein diametrically opposite, and slide in a corresponding light of the cylinder 40: the cylinder then has a pair of first, respectively second and / or third , lights 42, 42 ', each light of the pair being identical and shifted 180 ° with the other. In this case, preferably, each sliding element 44, 44 'has a lug 48, 48' for guiding in an opposite groove 50, 50 'of the casing 5 of the circuit breaker 1.

In particular if the contact is remote from the actuating cylinder 40, each sliding element 44, 44 'can be connected to the contact by via a rod 46, 46 '. Advantageously, the ends of the rods 46, 46 'which comprise the sliding elements 44, 44' are connected together, inside the cylinder 40, by an orthogonal bar 54 ensuring their spacing and their holding in position in order to limit the efforts.

It is understood that the embodiment with two sliding elements 44, 44 'is given by way of example and that one can for example design several elements, evenly distributed or not, on the periphery of the contact.

Each of the switches preferably, or only some of them, may comprise two sliding elements. According to an advantageous embodiment, only one of the switches, for example the vacuum interrupter, is actuated by means of actuating rods, connected or not to each other by bars.

Thanks to the actuation according to the invention, it is possible to control the different opening / closing movements of the switches 10, 20, 30 independently of each other. Moreover, unlike the spring, this control is not altered over time. The cam actuation 40 furthermore makes it possible to maintain compactness at the circuit-breaker pole 1, the cylinder 40 taking place within the usual circuit-breaker 1. The coaxiality of the circuits can therefore be maintained, even if it is possible, in particular in realizing an actuating rod 46 external to the cylinder 40, using a circuit breaker of intersecting axes as presented in the application EP 0 878 817 .

Claims (17)

1. An alternator disconnecter circuit-breaker (1) comprising:

   - a first switch (10) having a first pair of contacts (12, 14) that are mounted to move relative to each other in translation along a first axis (AA);

   - a circuit-breaker second switch (20) having a second pair of contacts (22, 24) that are mounted to move relative to each other in translation along a second axis, the second switch (20) being put in parallel with the first switch (10);

   - a disconnector third switch (30) having a third pair of contacts (32, 34) mounted to move relative to each other;

   - actuator means (40, 44, 46) for actuating a contact (14, 24, 34) of each switch (10, 20, 30); and

   - synchronization means (40, 42) making it possible, while breaking, for the contacts of the first switch (10) to separate before the contacts of the second switch (20) separate, said contacts of the second switch themselves separating before the third contacts (32, 34) separate fully;

   said circuit-breaker being characterized in that:

   the actuator means of the first and second switches and the synchronization means are coupled together and comprise a cylinder (40) mounted to move in rotation about an axis (AA) and presenting in its wall at least first and second slots (42₁, 42₂) that are helical in part;

   the actuator means of the first switch (10) comprise at least a first slider element (44) mounted to slide in a first slot (42₁) and secured firmly to a contact (14) of the first switch (10);

   the actuator means of the second switch (20) comprise at least one second slider element (44) mounted to slide in a second slot (42₂) and secured firmly to a contact (24) of the second switch (20).
2. A circuit-breaker according to claim 1, wherein the first axis of movement in translation, the second axis of movement in translation, and the axis of rotation of the cylinder (40) coincide.
3. A circuit-breaker according to claim 1 or claim 2, wherein the third switch (30) is in series with the second switch (20), and the resulting set of switches is in parallel with the first switch (10).
4. A circuit-breaker according to any one of claims 1 to 3, wherein the contacts (32, 34) of the third switch (30) are mounted to move in translation along a third axis.
5. A circuit-breaker according to claim 4, wherein all four axes (AA) coincide.
6. A circuit-breaker according to claim 4 or claim 5, wherein the cylinder (40) presents a third slot (42₃) that is helical in part, and at least a third slider element (44) is fastened to a contact (34) of the third switch (30) and slides in the third slot (42₃), the synchronization and actuation means of the three switches (10, 20, 30) being coupled together.
7. A circuit-breaker according to any one of claims 1 to 6, wherein the slider elements (44) of at least two switches (10, 20) are located inside the cylinder (40).
8. A circuit-breaker according to any one of claims 1 to 7, wherein the cylinder (40) presents two first, two second, and/or two third slots (42₁) having the same shape and offset by 180° relative to each other about the axis (AA) of the cylinder (40), and wherein the first, the second and/or the third contact is secured firmly to two first, two second and/or two third slider elements (44, 44') which are mounted to slide in the two first, two second, and/or two third slots (42₁).
9. A circuit-breaker according to any one of claims 1 to 8, wherein at least one slider element (44) is fastened to the contact in question via a connection rod (46).
10. A circuit-breaker according to claim 8, wherein the two slider elements (44) are fastened to at least one contact via a connection rod (46) and further comprising a connection bar (54) interconnecting the two connection rods (46, 46') inside the cylinder (40).
11. A circuit-breaker according to any one of claims 1 to 10, further comprising holding means (48, 50) for holding at least one contact (14) parallel to its axis (AA) of movement.
12. A circuit-breaker according to claim 11, wherein the holding means are constituted by guide grooves (50) in a casing (5) of the circuit-breaker (1).
13. A circuit-breaker according to any one of claims 1 to 12, wherein the shape of each slot has at least two portions having different slopes relative to the axis (AA) of the cylinder (40).
14. A circuit-breaker according to claim 13, wherein the helical portion of the second slot (42₂) lies between an initial end portion (42_2i) and a final end portion (42_2f) of slopes greater than the slopes of the helical portion (42_2m) relative to the axis (AA).
15. A circuit-breaker according to any one of claims 1 to 14, wherein the winding direction of the helical portions of the first and second or third slots (42_1f, 42_2m) are opposite.
16. A circuit-breaker according to any one of claims 1 to 15, further comprising control means (52) for controlling the cylinder (40), preferably selected from a drive chain and drive links.
17. A circuit-breaker according to any one of claims 1 to 16, wherein the second switch (20) is a vacuum chamber.

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