EP1855300B1 - Circuit-breaker disconnecting switch of an alternator activated by a servomotor - Google Patents

Description

TECHNICAL AREA

• un premier interrupteur comprenant une première paire de contacts mobiles l'un par rapport à l'autre en translation selon un premier axe ;
• un deuxième interrupteur de coupure comprenant une deuxième paire de contacts mobiles l'un par rapport à l'autre en translation selon un deuxième axe, le deuxième interrupteur étant mis en parallèle du premier interrupteur ;
• un troisième interrupteur sectionneur comprenant une troisième paire de contacts mobiles l'un par rapport à l'autre ;
• des moyens de synchronisation permettant, lors d'une interruption, la séparation des contacts du premier interrupteur avant la séparation des contacts du deuxième interrupteur, qui eux-mêmes se séparent avant que les troisièmes contacts ne se séparent entièrement.

The invention relates to an alternator disconnect circuit breaker comprising:

• a first switch comprising a first pair of movable contacts relative to each other in translation along a first axis;
• a second breaking switch comprising a second pair of movable contacts relative to each other in translation along a second axis, the second switch being placed in parallel with the first switch;
• a third isolator switch comprising a third pair of movable contacts with respect to each other;
• synchronization means allowing, during an interruption, the separation of the contacts of the first switch before the separation of the contacts of the second switch, which themselves separate before the third contacts do not separate entirely.

We already know ( EP 0 877 405 , EP 0878 817 ) appliances of this type. Their operation is ensured by a single command linked to the pole by a kinematics intended to ensure the sequence of operation of the circuit breaker. However, the combination of a command and a kinematic capable of opening a main circuit, a circuit breaker, then a disconnector and to operate a position indicator are of a very difficult design because of the antinomy of the requirements of the movements of each of the equipment and the duration of the movements of conventional controls of the circuit breakers. This sequence of operation is also made complex by the gathering of constraints sometimes geometric, sometimes temporal.

The preamble of claim 1 is known by WO 97/08723 A .

We also know ( EP 1 108 261 ) the use of a servo motor to operate a circuit breaker. However, the servo motor does not apply to the operation of several switching devices via the same kinematic chain.

The present invention relates to an alternator disconnect circuit breaker that overcomes these disadvantages. These objects are achieved by the features of the characterizing part of claim 1.

Thanks to these characteristics, it is possible to control the contact displacement characteristics as a function of time by an electronic method. This makes it possible to adjust the energy of the control to the exact needs of the movement to be made.

The servo motor actuates the synchronization means so as to obtain a contact opening speed of the first switch of between 1.5m / s and 2.5m / s during approximately the first half of the opening stroke of these contacts and a speed of between 0.5m / s and 0.8m / s during the second half of the opening stroke of these contacts.

Thanks to these characteristics, a fast movement is generated at the beginning of the cycle which slows down strongly during part of the cycle to wait for the extinction of the arc and the movement of the disconnector.

Preferably the synchronization means are designed so that the second switch opens substantially when the first switch has made half of its travel and at an opening speed between 1.5m / s and 2.5m / s.

Preferably the third switch opens when the first switch has traveled substantially two-thirds of its opening stroke. Advantageously, the synchronization means are designed in such a way that the opening speed of the third switch is between 1.5m / s and 2.5m / s.

• les contacts de la troisième paire du troisième interrupteur sont mobiles l'un par rapport en translation selon un troisième axe et l'un au moins des deuxième ou troisième axes est sécant du premier axe ;
• le troisième axe est sensiblement parallèle au premier axe ;
• le deuxième axe est sécant du premier axe ;
• les contacts de la troisième paire sont mobiles l'un par rapport à l'autre par pivotement autour d'un axe ;
• le troisième interrupteur est en série avec le deuxième interrupteur est leur ensemble étant parallèle avec le premier interrupteur ;
• le deuxième axe fait un angle sensiblement égal à 90 degrés par rapport au premier axe ;
• chaque paire de contacts est associée à l'actionnement mobile sous l'action de moyens de commande ;
• le disjoncteur comprend des moyens de synchronisation adaptés pour séparer dans cet ordre les contacts du premier interrupteur puis du deuxième interrupteur puis du troisième interrupteur.

Additional optional or alternative features are listed below:

• the contacts of the third pair of the third switch are movable relative to one another in translation along a third axis and at least one of the second or third axes is secant of the first axis;
• the third axis is substantially parallel to the first axis;
• the second axis is secant of the first axis;
• the contacts of the third pair are movable relative to each other by pivoting about an axis;
• the third switch is in series with the second switch is their set being parallel with the first switch;
• the second axis is at an angle substantially equal to 90 degrees with respect to the first axis;
• each pair of contacts is associated with the mobile actuation under the action of control means;
• the circuit breaker comprises synchronization means adapted to separate in this order the contacts of the first switch then the second switch and the third switch.

• la figure 1 illustre schématiquement le principe de coupure d'un disjoncteur sectionneur selon l'invention ;
• la figure 2 montre un mode de réalisation préféré du disjoncteur selon l'invention ;
• les figures 3A à 3F illustrent une séquence de coupure pour un disjoncteur d'alternateur selon un autre mode de réalisation de l'invention ;
• la figure 4 représente trois courbes qui représentent la course des trois interrupteurs en fonction du temps.

Other features and advantages of the invention will become apparent upon reading the following description of exemplary embodiments given by way of illustration with reference to the appended figures. In these figures:

• the figure 1 schematically illustrates the principle of breaking a circuit breaker according to the invention;
• the figure 2 shows a preferred embodiment of the circuit breaker according to the invention;
• the Figures 3A to 3F illustrate a break sequence for an alternator circuit breaker according to another embodiment of the invention;
• the figure 4 represents three curves representing the travel of the three switches as a function of time.

The operating principle of a circuit breaker, and in particular of an alternator circuit breaker 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 dielectric strength drop 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. According to a first embodiment illustrated in figure 2 each of the movable contacts moves in translation along a respective axis AA, BB, CC.

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, the first switch 10 is a switch in the air comprising a first tubular contact 12 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 sulfur hexafluoride which does not fulfill all the criteria ecological, and reduces costs. The mobile contact 24 the second switch 20 is moved by means of an actuating bar 44 movable along the axis BB.

Finally, the third switch 30 may, according to one embodiment, comprise a fixed contact 32 in which can be inserted another movable contact 34 along the axis CC opening / closing, the rod type. The rod 34 can be moved by means of a bar 46 in translation.

A servo motor 40 allows the displacement of the first 14, second 24 and third 34 movable contacts. For this purpose, the servomotor 40 is operatively connected to each of the actuators 42, 44, 46. Synchronization means 50 enable the relative openings of the switches 10, 20, 30 to be deferred.

The servomotor 40 first opens the first switch 10. This opening is, in a first part of the contact opening stroke at a relatively fast speed, between 1.5m / s and 2.5m / s and preferably equal to 2m / s. This first portion extends over substantially half of the opening stroke of the first switch 10.

When the first switch has reached a sufficient opening distance, the synchronization means 50 control the opening of the second switch 20. This sufficient distance is a function of the voltage. For example, an opening distance of 70mm can be sufficient for a voltage of 61kV. In any case, the second switch opens at the latest when the first switch has traveled halfway. For example, if the couse of the first switch is 170mm, the second switch will open at the latest when the movable contacts of the first switch have traveled 85mm. Its speed of opening and relatively fast, about 2m / s.

The first switch having traveled half of its travel, the servomotor slows down its speed of actuation of the synchronization mechanism 50 so that the second half of the opening of the contacts 12, 14 is relatively slow. Relatively slowly, it must be understood that the opening speed, expressed in m / s is about three times slower than the relatively fast speed. Thus, the relatively slow opening speed of the first switch will be between 0.5 and 0.8m / s.

The circuit breaker 20 being open, the synchronization means cause a certain time to be expected for the extinction of the circuit breaker arc 20 before moving the third contact 34 of the disconnector 30. The disconnector having reached a disconnection distance sufficient, the servo motor moves a position indicator (not shown) whose function is to indicate if the circuit breaker is open or closed.

Although each actuating bar 42, 44, 46 of this embodiment moves in translation and is integral with the same control means 40, the three axes AA, BB, CC of opening / closing are not necessarily parallel, at least one being intersecting the first axis AA for example. For reasons of compactness, it is preferable to have at least one BB axis in accordance with a angle of about 90 ° to the first axis AA. Although this configuration requires different arrangements of the pairs of contacts 12, 14; 22, 24; 32, 34 and their moving means 42, 44, 46, it appears that this geometry, a priori removed for reasons of complexity of synchronization, can be retained.

The synchronization means 50 may thus for example comprise, on the actuating bar 42 of the first switch 10, a generally longitudinal groove 52 along the axis AA of the bar but comprising an oblique part, the groove being associated with a element of the lug type 54 secured to the second actuating bar 44, so that, at first, during the movement of the first movable contact 14, the position of the lug 54 remains stable, then, in a second step, the lug 54 is displaced so as to move the second mobile contact 24 away from the second fixed contact 22.

It may be advantageous for the axes AA, CC of the switching switch 10 and the isolator 30 to be parallel, as shown in FIG. figure 2 but other options are possible, as described below. The synchronization means 50 may comprise a system similar to the previous one 52, 54 to delay the opening of the disconnector 30 with respect to the breaking switch 20; it is however preferable that the synchronization means 50 are directly associated between the first and third switches 10, 30. For example, the synchronization means 50 comprise a lever arm 56 coupled to an end portion at the third movable contact 34 and whose pivot axis is associated with a groove 58 located in the actuating bar 46 of the third switch 30: the actuating bars 42, 46 of the first and third switches 10, 30 are jointly moved by the actuating means 40, but a delay in the displacement of the third contact 34 is generated by the latency before the pivoting of the lever 56.

Other actuation and synchronization solutions are of course conceivable.

In particular, as illustrated in figure 3 , the section switch 30 'can operate on another principle of the type "knife disconnector". In the illustrated alternator circuit breaker, the main switch 10 'comprises two relatively translational movable contacts 12', 14 'disposed in an envelope such as a 200 mm diameter tube; in an operating position illustrated in figure 3A , the alternator current I ₀ flows in this main circuit (see arrow).

When a break is required, the servomotor 60 separates relatively quickly the two contacts 12 ', 14': the operation is performed by means of a bar 42 '. At first illustrated in figure 3B current I retains its main path, but an arc is formed, covering the distance between the two contacts 12 ', 14' of the switch 10 '; then, the interruption on the main circuit is completed ( figure 3C ), and the current flows only on the auxiliary circuit, the delay means 50 'having delayed the opening of the contacts 22', 24 'of the switch 20'. For example, the dielectric distance on the main circuit makes it possible to hold the transient recovery voltage, that is to say that the actuating bar 42 'moves about half of its total stroke before opening the chamber at 20 'vacuum.

To cut off the short-circuit current, the servomotor 60 'moves in translation the two relatively movable contacts 22', 24 'of the breaking chamber 20' along an axis orthogonal to the translation axis of the first switch 10 ': 3D figure . The displacement of the two contacts 22 ', 24' is effected by means of an actuating bar 44 'orthogonal to the bar 42', integral with the latter via the delay means 50 ', for example by means of a lug 54 'moving in a groove 52' of the first actuating bar 42 '. When spacing the contacts 22 ', 24', an arc is created, then, very quickly, the cut is completed: figure 3E .

During these steps, the switch 30 'section is not solicited by the delay means 50'. From this point, the servo motor 60 'operates the contacts relatively slowly. The fixed contact 32 'of the disconnector 30' is integral with the fixed contact 12 'of the first switch; the second contact 34 'of the disconnector 30' is relatively movable by pivoting about an axis 36 '. The actuating means 46 'of the contacts 32', 34 'of this switch 30' are integral with the first bar 42 '; moreover, at the pivot 36 ', the movable contact 34' comprises delay means 56 'in the form of a groove complementary to a lug of the actuating bar 46' but allowing relative movement before driving by the bar 46 'of the contact 34' rotating about its axis 36 ': finally, as illustrated in FIG. figure 3F , the section is completed.

Naturally, other operations are possible: for example, the disconnector 30 'can also move in a "horizontal" plane, that is to say, in the frame shown, by pivoting about a parallel axis 36' at one of the translation axes of the contacts of the other two switches 10 ', 20'.

On the figure 4 the reference 110 represents the curve of the opening stroke of the first contact 10, the reference 120 represents the opening stroke of the second switch 20 and the reference 130 the opening curve of the third switch 30. As can be seen, the curve 110 has a steep slope portion 132 and a portion 134 of a relatively lower slope. The part 132 corresponds to the part of the cycle during which the servomotor 40 or 60 'actuates the synchronization means relatively quickly and the part 134 corresponds to the second part of the opening cycle of the isolating circuit-breaker during which the servo-motor actuates relatively slowly these same means of synchronization. By way of example, the part 132 of the curve 110 corresponds to an opening speed of 2 m / s while the part 134 of this same curve corresponds to an opening speed of 0.6m / s. In other words, the opening speed is more than three times greater during the relatively fast opening cycle portion than during the relatively slow opening cycle portion. The transition point 135 between the two parts of the curve is located substantially at half of the opening stroke of the first switch 10. As can be seen in FIG. figure 4 the opening 136 of the cutoff switch 20 is substantially at the end of the fast opening period and the slope of the portion 136 is substantially equal to the slope of the portion 132, that is to say that it corresponds to a speed of approximately two m / s, in the example. After the end of the opening of the cut-off switch 20, a certain delay is expected, for example about ten milliseconds as represented by the line segment 138 before the opening of the third isolating switch 30. At this point, the first switch traveled substantially two-thirds of its opening stroke. The opening of the disconnector switch 30 is then performed relatively quickly, as shown by the slope 140 of the curve 120, that is to say at a speed of about 2m / s and this although at this time the servo motor actuates relatively slowly the opening of the first contact. The relatively rapid opening of the third switch is obtained by the construction of the synchronization means, for example by the ratio of the lever arms 42 and 56 (see FIG. figure 2 ).

Claims (12)

1. An alternator disconnector circuit-breaker comprising:

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

   - a circuit-breaker second switch (20, 20') having a second pair of contacts (21, 24, 22', 24') that are mounted to move relative to each other in translation along a second axis (BB), the second switch (20, 20') being put in parallel with the first switch (10, 10');

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

   - synchronization means (50, 50') make it possible, while breaking is taking place, for the contacts of the first switch (10, 10') to separate before the contacts of the second switch (20, 20') separate, the contacts of the second switch themselves separating before the third contacts (32, 34, 32', 34') separate fully;

   characterised in that the synchronization means are actuated by a servomotor (40', 60') and in that the servomotor (40, 60') actuates the synchronization means (50, 50') in a manner such as to obtain an opening speed at which the contacts (12, 14, 12', 14') of the first switch (10) open that lies in the range 1.5 m/s to 2.5 m/s for about the first half of the opening stroke of said contacts and an opening speed at which said contacts open that lies in the range 0.5 m/s to 0.8 m/s for the second half of the opening stroke of said contacts.
2. A circuit-breaker according to claim 1, characterized in that the synchronization means (50) are designed in a manner such that the second switch opens when the first switch (10) has traveled along substantially one half of its stroke at an opening speed lying in the range 1.5 m/s to 2.5 m/s.
3. A circuit-breaker according to claim 1 or claim 2, characterized in that the third switch opens once the first switch (10) has traveled along substantially two-thirds of its opening stroke.
4. A circuit-breaker according to claim 3, characterized in that the synchronization means are designed in a manner such that the opening speed of the third switch (30) lies in the range 1.5 m/s to 2.5 m/s.
5. A circuit-breaker according to any one of claims 1 to 4, characterized in that the contacts of the third pair of the third switch (30) are mounted to move relative to each other in translation along a third axis (CC), at least one of the second and third axes intersecting the first axis (AA).
6. A circuit-breaker according to any one of claims 1 to 4, in which the third axis (CC) is substantially parallel to the first axis (AA).
7. A circuit-breaker according to any one of claims 1 to 4, characterized in that the contacts of the third pair (32', 34') are mounted to move relative to each other by pivoting about an axis (36').
8. A circuit-breaker according to any one of claims 1 to 7, characterized in that the third switch (30, 30') is in series with the second switch (20, 20') and the second and third switches together are in parallel with the first switch (10, 10');
9. A circuit-breaker according to any one of claims 1 to 8, characterized in that the second axis (BB) forms an angle that is substantially equal to 90° relative to the first axis (AA).
10. A circuit-breaker according to any one of claims 1 to 9, characterized in that each pair of contacts is associated with an actuator bar (42, 44, 46) that is mounted to move under action from control means (40).
11. A circuit-breaker according to any one of claims 1 to 10, characterized in that the synchronization means (50, 50') are adapted to separate the contacts of the first switch (10, 10'), then the contacts of the second switch (20, 20'), and then the contacts of the third switch (30, 30'), in that order.
12. A circuit-breaker according to claim 11, characterized in that the synchronization means (50, 50') are adapted to re-close the contacts of the switches (10, 20, 30, 10', 20', 30') successively in the reverse order relative to the order in which they are separated.

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