FR3045228A1 - METHOD FOR CONTROLLING AN ELECTRICAL CUTTING APPARATUS AND ELECTRICAL INSTALLATION COMPRISING AN ELECTRICAL CUTTING APPARATUS - Google Patents

Abstract

The invention relates to a method for controlling the opening of a mechanical breaking device in an AC high-voltage electrical circuit, having two electrodes respectively subjected to an alternating electric potential at a floating potential, characterized in that the method comprises: an initial opening step during which a relative movement of the two electrodes is performed at a first average speed of separation greater than 0.05 meters per second, preferably greater than 0.1 meters per second; - At least one stabilization step, during which a relative movement of the two electrodes is performed at an average rate of stabilization gap less than 0.03 meters per second. The invention also relates to an electrical installation implementing such a method.

Description

The invention relates to the technological field of devices for cutting high-voltage electrical circuits, more particularly their control methods, in high-voltage AC electrical installations.

Traditionally, power grids are infrastructure at the scale of a region, a country or a continent, in which electrical energy is transported under high AC voltage over several tens, hundreds or thousands of kilometers. .

In these networks there are electrical installations, including electrical substations or substations, in which there is at least one electrical circuit breaker device.

In an electrical circuit, there is generally at least one voltage source, and at least one voltage user, which can include any appliance or set of appliances or any network having such appliances that use the electrical energy to transform it into electricity. another form of energy, for example mechanical energy, and / or heat, and / or electromagnetic, etc ...

In an electrical circuit, electrical circuit breakers are generally available to interrupt the flow of electrical current in the circuit, generally between the voltage source and the voltage user, or between the voltage source and the earth. . There are various types of devices for cutting off electrical circuits. For example, there are known circuit breakers, which are devices for mechanical breaking of the electrical circuit and which are designed and dimensioned to allow in particular an opening in load or fault mode of the electrical circuit in which they are interposed. However, circuit breakers are complex, expensive and bulky devices and are intended for network protection functions. There are also known electrical circuit cutting devices of simpler design, such as disconnectors which are not generally designed to perform circuit interruptions in charge, but rather, to ensure, in a circuit where the flow of current is already interrupted by another cut-off device, the safety of property and persons during the interventions, by ensuring a high level of electrical insulation predetermined between an upstream portion of the circuit, connected to the voltage source, and a downstream portion of the circuit.

Furthermore, it is known to use, in particular, for high-voltage circuits, so-called "metal casing" devices where the active cutting members are enclosed in a sealed enclosure, sometimes called a tank or metal casing, filled with a insulating fluid. Such a fluid may be a gas, commonly sulfur hexafluoride (SFO), but liquids or oils are also used. This fluid is chosen for its insulating nature, in particular so as to have a dielectric strength greater than that of dry air at equivalent pressure. In particular, metal-enclosed devices can be designed more compactly than devices where the cut-off and insulation are made in the air.

A conventional "metal casing" disconnector includes in particular two electrodes which are held by insulating supports in fixed positions remote from the peripheral wall of an enclosure, for example the metal casing, which is at ground potential. These electrodes are electrically connected or electrically separated according to the position of a movable connection member forming part of one of the electrodes, for example a sliding tube actuated by a control. The tube is generally carried by one of the electrodes, to which it is electrically connected, and the separation of the tube from the opposite electrode is likely to create an electric arc. A disconnector is usually located in an electrical substation. It is connected to the other elements of the substation, for example by connecting bars. On each side of the disconnector, we can find other elements of a substation such as a circuit breaker, a power transformer, an air crossing, etc ...

In certain electrical circuit configurations, it is thus possible to provide for a disconnector to be arranged between an alternating voltage source, in particular a high-voltage source, and another breaking device such as a circuit-breaker, the circuit breaker thus being in a downstream portion of the circuit. circuit with respect to the voltage source and the disconnector. Thus, to open such an electrical circuit and isolate it from the voltage source, it is generally proceeded to an opening of a first breaking device, for example of the circuit breaker type, to stop the flow of current in the circuit. Then, to isolate the downstream portion of the circuit, the disconnector is opened. In such a case, a first electrode of the disconnector is electrically connected, directly or indirectly, to the AC voltage source while the second electrode, after opening of the circuit, is electrically isolated from any source of voltage and any electrical mass, therefore to a floating electric potential. It will be considered that an electrode is electrically isolated from any source of voltage and from any electrical mass, and thus to a floating electrical potential, if it forms a non-zero capacitance with the surrounding conductive elements which would be connected to a specific potential, for example by a voltage source or electrical ground, ie for example the electrode connected to the voltage source (upstream circuit), the metal shell connected to the earth, and / or any part of another breaking device that is part of downstream circuit. Thus, during an opening operation of a disconnector in such an installation, the first electrode has an electrical potential that varies over time as a function of the AC voltage delivered by the voltage source to which it is connected. On the contrary, the second electrode being isolated, its electric potential is not determined. It can be the electrical potential of the electrode at the moment of the last contact in the relative position of electrical closure of the two electrodes. After opening, a capacitive coupling may remain between the two electrodes whereby the potential of the second electrode can be varied. However, this phenomenon will be neglected here because its amplitude is generally significantly lower than the electrical potential existing at the time of the last contact or via an electric arc between the two electrodes.

On the other hand, during the relative opening movement of the electrodes, particularly at the beginning of this relative movement, just after the position of the last electrical contact between the two electrodes in the direction of opening, it is known that electric arcs are susceptible to appear between the two electrodes.

The problem underlying the invention will be illustrated with reference to FIG. 4 in which the variations over time of the electric potential Ui, U2 of each of the two electrodes with respect to a ground potential have been illustrated during a relative opening movement of the electrodes. It will be considered that this relative opening movement is done with a constant speed of the relative movement of the two electrodes corresponding to a spacing between the two electrodes which increases steadily over time. Due to this increase in the spacing, there is a corresponding constant increase in the dielectric strength between the two electrodes, that is to say the potential difference required between the two electrodes to allow the triggering of an arc electric. In other words, the dielectric strength between the two electrodes, which is zero for the relative electrical closure position, increases progressively from an initial value as soon as the physical contact between the two electrodes is lost, up to a dielectric withstand value. final corresponding to the relative position of electrical opening of the two electrodes, which ensures the isolation between the upstream part and the downstream part of the electrical circuit in which the disconnector is interposed.

In the relative electrical closing position of the two electrodes, the two electrodes of the disconnector are at each instant at the same electrical potential, which is visible on the left-hand part of FIG. 4, this electrical potential being in this case directly dictated by the AC voltage delivered by a voltage source. It is illustrated in FIG. 4 a moment to, which is the moment of the loss of physical contact between the two electrodes. Beyond this moment, it is considered that the two electrodes are no longer physically in contact with each other. However, in the moments immediately following the loss of contact, and particularly in the context of a high-voltage installation, an electric arc is created, and maintains, at least initially, the electrical potential of the second electrode. substantially at the same level, at each moment, than that of the first electrode. However, after a moment ti, the two electrodes are separated from each other by a distance such that the electric arc is interrupted a first time, allowing the appearance of a potential difference between the two electrodes . However, as soon as this potential difference exceeds the dielectric strength defined by the spacing distance, a new arc is formed, instantly returning the potential of the second electrode to that of the first electrode. As the time goes by, so that the distance between the two electrodes increases, the interruption time of the arcs becomes longer and longer because of the progressive increase in the dielectric strength between the two electrodes. which results directly from the increase in the spacing between the two electrodes. In the example of FIG. 4, there exists a moment t2 from which there appears only one electric arc per half-period of alternation of the electric potential of the first electrode. When such an arc appears, the potential of the second electrode is brought approximately to the electrical potential of the first electrode at the moment of the arc. This arc is fugitive in that it disappears when the two electrodes are substantially at the same potential due to the electric arc. It will be recalled here that the second electrode is at a floating potential and not at a determined potential as it would be if it were connected to the electrical ground or to another voltage source. However, as soon as this electric arc is extinguished, since the first electrode is connected to an AC voltage source, the potential of the first electrode continues to vary while the electrical potential of the second electrode remains at the level it has. reached after the previous arc. This results in an increase in the electrical potential difference between the two electrodes, and when this potential difference exceeds the electrical insulation capacity between the two electrodes for the instantaneous relative position of the two electrodes, a new fugitive arc is formed.

These arcs continue to occur until a time t3, which corresponds to the moment of the last electric arc of the opening maneuver.

Beyond this last electric arc, the dielectric strength between the two electrodes is too important for a new arc to form. Thus, when the two electrodes reach their relative electric opening position, the second electrode is at a final electric potential Uf which results from the last electric arc, and which therefore results from the instant at which this last electric arc was triggered. and the electrical potential of the first electrode at the instant of the last electric arc.

Simulations have shown that, in a given installation, with a given AC voltage source, and with a method of opening the given disconnector of the type described above, this terminal value of the electrical potential of the second electrode was highly random. . These simulations were presented during an oral presentation at the CIGRE New Dehli 2013 Conference (Thomas Bertellot, Alain GIRODET, Paul VINSON, Mathieu BERNARD, see also CIGRE 570 brochure). Working Group A3.28 February 2014 - Phenomena Switching for EHV and UHV Equipment "). This communication exposed in particular that opening speeds of 0.05 or 0.1 m / s made it possible to obtain, with greater probability, a terminal value of the electric potential of the second electrode lower than that obtained for an opening speed of 0.5. m / s. A similar lesson can be drawn from the document "Influence of the Switching Speed of the Disconnector on Very Fast Transient Overvoltage" (Shu Yinbiao, Han Bin, Lin Ji-Ming, Chen Weijiang, Ban Liangeng, Xiang Zutao, and Chen Guoqiang - IEEE ON POWER DELIVERY TRANSACTIONS, VOL 28, NO 4, OCTOBER 2013).

However, it appears that this terminal value of the electric potential of the second electrode, sometimes called trapped charge, is not without incidence.

It should be noted first of all that between the instants t2 and t3, the potential difference between the two electrodes at the moment of the triggering of an electric arc, or ignition voltage AU, increases with each alternation. But for each electric arc, a high-frequency surge appears on the first microseconds. We call this surge VFTO (Very Fast

Transient Overvoltage). The higher the ignition voltage AU between the two electrodes of the disconnector, the larger the corresponding VFTO. The VFTO propagates at each point electrically connected to the disconnector: it spreads in other elements of the substation located on both sides of the disconnector. The VFTO is therefore likely to spread at the level of power transformers, bushings, circuit breakers ... The surge created by the VFTO is thus stressing the phase-to-ground insulation of all the elements connected to the disconnector.

Solutions to this problem have already been proposed, which are not entirely satisfactory.

A first known solution consists in the use of a resistance switch. In such a device, an electrical resistor is inserted into the current flow during the opening maneuver only. In such a disconnector, the resistor is located between one of the electrodes of the disconnector and a resistor electrode. The electric arcs then occur between the disconnector tube and the resistance electrode. Its value can go up to 1Ι <Ω. This first solution has limitations constituted by the significantly larger size of the disconnector, its higher cost because of the additional parts and because of an increased need for maintenance, and a lower reliability due to the presence of the electrical resistance. .

A second solution, described for example in JP-2000.067705 consists in the use of a disconnector for which the value of the priming voltages between the two electrodes is controlled by causing electric arcs to ignite with a laser beam. The laser source is positioned outside the disconnector and an optical device consisting of mirrors and or lenses makes it possible to bring the energy of the laser between the tube and the opposite electrode. It is conceivable that such a solution is expensive and complex.

There therefore remains the need to limit the high-frequency overvoltages due to electric arcs that appear on opening in a mechanical breaking device whose one electrode is subjected to an alternating electric potential, and whose other electrode is at a floating electrical potential. , while maintaining simple and inexpensive facilities.

For this purpose, the invention proposes a method for controlling the opening of a mechanical breaking device in an alternating high-voltage electrical circuit, of the type comprising two electrodes, a first of which is subjected to an alternating electric potential having a period of alternation. , and a second of which is electrically isolated from any source of voltage and any electrical mass, the two electrodes of the mechanical apparatus being movable relative to each other in a controlled opening movement, between a relative position electrical closure, in which they establish a nominal electrical connection of the apparatus, and at least one final electrical opening relative position in which the two electrodes are spaced from each other by a final gap, characterized in that the method comprises: an initial opening step comprising at least one fast opening time interval whose duration is equal to less than 1 times the period of alternation of the alternating potential of the first electrode and during which a relative movement of the two electrodes takes place at a first average rate of separation greater than 0.05 meters per second, preferably greater than 0.1 meters per second ; at least one stabilization step, subsequent to the initial opening step and comprising at least one stabilization time interval whose duration is at least 5 times the alternating period of the alternating potential of the first electrode and corresponding to spacings of the two electrodes between 10% and 90% of the final spacing, during which a relative movement of the two electrodes is performed at an average stabilizing spacing speed of less than 0.03 meters per second.

According to other optional features of such a process, taken alone or in combination: the method comprises, after the stabilization step, at least one opening continuation step comprising at least one tracking time interval of aperture whose duration is at least 5 times the alternating period of the alternating potential of the first electrode and during which a relative movement of the two electrodes takes place at an average spacing speed greater than 0.03 meters per second, preferably greater than 0.05 meters per second, more preferably greater than 0.1 meters per second. The process comprises, after an opening continuation step, a secondary stabilization step comprising at least one secondary stabilization time interval whose duration is at least 5 times the period of alternation of the alternating potential of the first electrode, in which a relative movement of the two electrodes takes place at an average spacing speed of less than 0.03 meters per second. The method comprises a final opening step during which the electrodes reach their final relative position of opening. - A stabilization step begins for an intermediate relative position of the two electrodes between the relative position of closure and the final relative position of opening, and distinct from the relative position of closure and the final relative position of opening. - A stabilization step is triggered to correspond to a predetermined relative position of the two electrodes. - A stabilization step is triggered according to at least one operating parameter of the device. - A stabilization step is triggered at least according to the duration of a time interval between two arcs between the first electrode and the second electrode during the opening movement. During the initial opening step, a time interval is detected between two electric arcs between the first and the second electrode, and the duration of the time interval is compared with a reference value above which a stabilization step is triggered. - A stabilization step is triggered at least according to the voltage between the two electrodes at the time of the initiation of an electric arc between the two electrodes. - An opening continuation step is triggered after the lapse of a predetermined period of time following a last electric arc detected between the two electrodes. The triggering of a secondary stabilization step is determined at least as a function of the detection of an electric arc between the first and the second electrode during an opening continuation step. During a stabilization step, the electrodes occupy at least one relative position of last arc for which: there exists an electric potential value of the first electrode subjected to an alternating electric potential which creates, for this position, and for a value potential of the second electrode, an electric arc between the two electrodes, and - the electric arc brings the second electrode to a final potential for which the electrical potential difference between the first electrode and the second electrode is less than the holding dielectric strength between the electrodes for said position. During the stabilization step, the electrodes occupy at least one relative position for which the spacing value of the electrodes is between 10% and 50%, more preferably between 10% and 30% of the spacing value of the electrodes; in a final opening position. During the stabilization step, the electrodes occupy at least one relative position for which the spacing value of the electrodes is between 40% and 90%, more preferably between 60% and 90% of the spacing value of the electrodes; in a final opening position. - A stabilization step comprises at least one stop of the relative movement of the two electrodes. - A stabilization step consists of stopping the relative movement of the two electrodes. - A stabilization step has a duration equal to at least 5 times, alternately at least 10 times, alternately at least 20 times the alternating period of the electrical potential to which the first electrode is subjected. - A stabilization step has a duration less than 75 times the alternating period of the electrical potential to which the first electrode is subjected, preferably less than 50 times the alternating period of the electrical potential to which the first electrode is subjected. The second average spreading velocity is chosen so that the rate of increase of the minimum dielectric strength of the apparatus, caused by the increase of the spreading value, increases at a speed of less than 1.0 pu / s, preferably less than 0.5 pu / s, where 1 pu is the peak value of the electrical potential to which the first electrode is subjected with respect to the earth. - The electric potential of the second electrode when the two electrodes reach their final relative opening position is less than 0.5 pu, where 1 pu is the peak value of the voltage to which the first electrode is subjected to earth. The invention also relates to an electrical installation comprising an apparatus for mechanical breaking of an alternating high-voltage electrical circuit, of the type comprising two electrodes of which a first is subjected to an alternating electric potential and a second of which is electrically insulated from any voltage source. and of any electrical mass, the two electrodes of the mechanical apparatus being movable relative to each other in an opening movement controlled by a control device, between a relative electrical closing position, in which they establish a nominal electrical connection of the apparatus, and at least one relative electrical opening position in which the two electrodes are spaced from each other, characterized in that the control device is configured to implement a method control having one or more of the above characteristics.

According to other optional features of such an installation, taken alone or in combination: the control device comprises an actuator for controlling the relative movement of the electrodes, and a controller which controls the actuator, the controller being programmed to set implement a control method having one or more of the above features. - The control device comprises an actuator for controlling the relative movement of the electrodes via a transmission mechanism connecting the actuator to at least one of the electrodes, the transmission mechanism being configured to implement a control method having one or more of the above characteristics.

Various other characteristics appear from the description given below with reference to the accompanying drawings which show, by way of non-limiting examples, embodiments of the subject of the invention.

Figure 1 schematically illustrates an electrical installation according to the invention comprising an electrical circuit breaking device, here illustrated in the relative position of electrical closure of its electrodes.

Figures 2 and 3 are schematic views of the mechanical circuit breaker apparatus of FIG. 1, respectively illustrated in an intermediate position and in relative position of electrical opening of its electrodes.

FIG. 4 illustrates the variations over time of the respective electric potential of the two electrodes, measured with respect to the earth, of a mechanical circuit breaking device, during a relative movement of opening at constant speed of the electrodes .

FIGS. 5A to 5D illustrate four examples of a method for controlling the opening of a mechanical breaking device according to the invention, by illustrating the variation over time of the gap E between the two electrodes of the apparatus.

Figure 6 is a diagram illustrating the progress of an example of a method of controlling the opening of a mechanical breaking device according to the invention.

FIGS. 7A to 7D illustrate an embodiment of a mechanical circuit breaking device comprising a transmission mechanism connecting an actuator to one of the electrodes, the transmission mechanism being configured to implement a method according to the invention. .

It is illustrated in Figs. 1 to 3 the main components of a device for mechanical shutdown of a high voltage electrical circuit, including very high alternating voltage, representing three different relative positions between the electrodes of the switchgear.

Such an apparatus is intended to open or close an electrical circuit in which alternative nominal currents, that is to say, established currents for which the apparatus is intended to operate in a continuous manner without damage, may be circulated in a manner in which voltage greater than 1000 V ac, see even under very high voltage, that is to say a voltage greater than 50 000 V ac. The apparatus is a mechanical cutoff device insofar as the opening of the electrical circuit is obtained by separating and spacing two contact pieces so as to interrupt the flow of a current through the apparatus. Of course, the closing of the electrical circuit is obtained by the displacement until the two contact parts come into contact so as to restore a flow of current through the apparatus.

In the exemplary embodiment, the mechanical cut-off device is a disconnector. In the example, the switching device is intended to cut a single electrical circuit, for example a phase, but the invention could be implemented in an apparatus intended to cut several electrical circuits, then including, for example within of the same enclosure, several devices of cut in parallel. The invention will more particularly be described in the context of a cutoff device of the type called "under metal envelope". The apparatus 10 thus comprises an enclosure 12 which delimits an internal volume 16 of the enclosure 12. Preferably, in the operating configuration of the device, the enclosure 12 is sealed with respect to the outside of the enclosure 12 The enclosure 12 may comprise one or more openings (not shown) allowing, at least for maintenance or mounting operations, access to the internal volume 16 from outside the enclosure, or allowing the volume 16 to be placed in communication with another volume of another enclosure contiguous to the enclosure 12 around the opening. The openings are thus intended to be closed off, for example by portholes or covers, or are intended to put in communication the internal volume 16 of the chamber 12 with another enclosure itself sealed, by waterproof matching of the opening with a corresponding opening of the other enclosure. Thanks to this seal, the internal volume 16 of the chamber 12 can be filled with an insulating fluid that can be separated from the atmospheric air. The fluid may be a gas or a liquid. The pressure of the fluid may be different from the atmospheric pressure, for example a pressure greater than 3 bars absolute, or may be a very low pressure, possibly close to the vacuum. Vacuum would be, in the sense of the invention, assimilated to an insulating fluid. The insulating fluid may be air, particularly dry air, preferably at a pressure greater than atmospheric pressure. However, preferably, the fluid is chosen for its high insulating properties, for example having a dielectric strength greater than that of dry air under conditions of equivalent temperature and pressure.

In general, the apparatus 10 comprises at least two electrodes which are intended to be electrically connected respectively to an upstream portion and a downstream portion of the electrical circuit to be cut. The two electrodes are movable relative to each other in an opening movement, between at least one relative position of electrical closure, illustrated in FIG. 1, in which they establish a nominal electrical connection of the apparatus, and thus corresponding to a closed state of the apparatus, and a relative electrical opening position, FIG. 3 corresponding to an open state of the apparatus. In the example illustrated, the apparatus 10 comprises in particular a first fixed electrode 20 and a second electrode 22 which comprises a fixed main body and a movable connection member 24. It is understood that the mobile connection member could be part of the first electrode 20, or that each of the two electrodes 20, 22 could comprise a movable connection member.

In the illustrated example, each electrode 20, 22 is fixed in the enclosure 12 by means of an insulating support 26. Outside the enclosure 12, the apparatus 10 comprises a connection terminal 28, Which is electrically connected to the corresponding electrode 20, 22. One of the terminals is intended to be connected to an upstream portion of the electrical circuit while the other of the terminals is intended to be connected to a downstream portion of the electrical circuit. In an arbitrary manner, and without this having any particular significance as to the polarity or the direction of current flow, the portion which is connected to the first electrode 20 by the connection terminal is referred to as the upstream portion of the electrical circuit. 28. Consequently, the downstream portion of the electrical circuit is the portion which is connected to the second electrode 22, via the connection terminal 30.

In the example, each electrode 20, 22 is permanently electrically connected to the connecting terminal 28, 30 associated, regardless of the open or closed state of the switchgear.

The main bodies of the two electrodes 20, 22 are arranged in the internal volume 16 in a fixed manner, spaced apart from the peripheral wall of the enclosure 12, and spaced apart from one another so that an isolation space The interelectrode electrode is arranged in the direction of a central axis A1 between the portions facing their respective outer peripheral surfaces.

In the example illustrated, the mobile connection member 24 of the second electrode of the apparatus may comprise a sliding tube, of axis A1, which is slidably guided along the central axis Al, which will arbitrarily be described as longitudinal. in the second electrode 22. The connecting member 24 is movable in an opening movement with respect to the opposite electrode 20, between a relative position of electrical closure, visible in FIG. 1, and wherein the electrical connection member 24 establishes a nominal electrical connection with said opposite electrode 20, and a relative electrical opening position, visible in FIG. 3, passing through intermediate relative positions such as that illustrated in FIG. 2. In the illustrated example, the mobile connection member 24 is preferably made of conductive material, for example metal, and is electrically connected to the main body of the second electrode, thus electrically connected with the associated connection terminal 30 permanently, regardless of the position of the mobile connection member 24.

In its relative closing position, the connecting member 24 is moved longitudinally along the central axis A1 in the direction of the first electrode 20, across the interelectrode electrical isolation space. In the remainder of the text, it is considered that the relative position of closure is the position of the last electrical contact between the two electrodes, in the direction of opening of the breaking apparatus, for which an electric current flow is possible by conduction through a mechanical contact of the two electrodes. In some devices, there may be a dead path between an extreme electric closing position and the position of the last electrical contact between the two electrodes, in the opening direction of the breaking device. However, only this position of last electrical contact is considered here. In known manner, the connection member 24 is moved from the relative closing position to the relative opening position by a control device 42 which, in this embodiment, comprises a connecting rod 44 movable in a direction substantially parallel to Al axis and itself controlled by a rotary lever 46. The mechanical breaking device 10 is intended to be included in an electrical installation 14 comprising an AC high voltage electrical circuit, an example of which is illustrated in FIG. 1.

In such an installation, the first electrode 20 is for example electrically connected respectively to an upstream portion of the electrical circuit comprising an alternating voltage source 32 which may be a primary source, such as an alternating voltage generator, or a secondary source such as transformer or converter. Between the AC voltage source 32 and the switchgear 10, one can find all kinds of electrical devices, including electrical circuit breakers. However, one places oneself in a state of this upstream portion of the circuit in which the first electrode is subjected to an alternating electric potential. In the illustrated case, the first electrode is subjected to an alternating electric potential imposed directly or indirectly by the voltage source 32.

In contrast, the other electrode, in this case the second electrode 22 is, at least for certain configurations of the installation, electrically isolated from any voltage source and from any electrical ground. As explained above, the second electrode 22 is connected to the downstream part of the electrical circuit which may in particular comprise a breaking device 34, for example a circuit breaker, which makes it possible to interrupt the current between the breaking device 10 and, by For example, a voltage user network 36. In the configuration in which the switchgear is in the relative opening position and in which the downstream circuit breaker 34 is open, the second electrode 22 is therefore at a floating electrical potential because it is not electrically connected to any other voltage source or electrical ground.

In order to limit the absolute value of the trapped charge at the second electrode, the invention proposes a new method for controlling the opening of the mechanical breaking device 10.

According to examples partially illustrated in Figs. 5A, 5B and 5C, the method may comprise: a) an initial opening step during which a relative movement of the two electrodes 20, 22 is effected, from the relative closing position, at a first maximum average speed d spacing measured during at least one fast opening time interval whose duration T1 is one time the alternating period of the alternating potential of the first electrode; b) at least one stabilization step, subsequent to the initial step, during which a relative movement of the two electrodes 20, 22 is performed at an average stabilizing gap speed, determined over a period of stabilization time whose duration T2 is at least 5 times the alternating period of the alternating potential of the first electrode and corresponding to the spacings of the two electrodes of between 10% and 90% of the final spacing (Ef), and less than the first average maximum spreading speed. Advantageously, the average stabilizing gap speed may be less than 50% of the first average maximum spreading speed. The initial step of rapid opening makes it possible to obtain a clear separation of the two electrodes and makes it possible to reduce the total duration of the opening movement.

As will be seen from the following examples, a stabilization step may comprise a step in which the two electrodes 20, 22 continue to deviate from each other according to their relative opening movement. However, preferably, a stabilization step comprises at least one stop of the relative movement of the two electrodes. As will be visible for example in the context of the example of FIG. 5B, a stabilization step may consist of stopping the relative movement of the two electrodes 20, 22.

Such a method can be implemented with a manual control of the relative opening movement of the two electrodes 20, 22 of a mechanical switching device for an electrical circuit. However, it will advantageously be provided that this method is automated in a mechanical breaking device.

Thus, in an apparatus for mechanical breaking of an electrical circuit, the control device 42 for the relative movement of the two electrodes is for example configured to implement a control method having the above characteristics, and / or possibly the either of the additional features of the methods which will be described below.

For example, the control device 42 may comprise an actuator 48, for example an electric motor, a pneumatic motor or an energy storage motor, capable of actuating the relative movement of the two electrodes 20, 22, possibly by the intermediate of a transmission mechanism. In the illustrated example, the transmission mechanism comprises the connecting rod 44 and the lever 46. The transmission mechanism connects the actuator 48 to at least one of the electrodes to control the movement of the electrode. In this case, the transmission mechanism 44, 46 causes the movable connecting member 24 to move, without causing movement of the main bodies of the first and second electrodes. The control device 42 comprises a controller which controls the actuator 48, for example in the form of an electronic control and control unit 52. The electronic control and control unit 52 can be made in the form of several separate components communicating with each other. The electronic control and control unit 52 may for example be configured to be able to control the control device 42, in particular the actuator 48, to control the relative movement of the two electrodes in particular as a function of a time interval between two arcs. during an opening movement of the two electrodes. In particular, the electronic control and control unit 52 may for example be programmed to control the actuator so that the speed of the actuator 48 follows the above steps, and possibly one or the other of the steps. described below.

Alternatively, or in addition, it can be provided that the control device comprises an actuator for controlling the movement of the electrode by means of a transmission mechanism connecting the actuator to at least one of the electrodes, the mechanism of transmission being configured so that, for example for a constant speed of the actuator, at least one of the electrodes is controlled by the transmission mechanism and follows the above steps, and optionally one or the other of the steps described below. An example of such an embodiment will be described in more detail below.

Referring more particularly to Figs. 5A to 5D, on which several variants of the relative movement of the two electrodes 20, 22 as a function of time have been illustrated during an opening maneuver of the breaking device 10, it is understood that the two electrodes 20, 22 pass, during this opening movement, the relative position of electrical closure in which a gap E between the two electrodes is zero, the relative position of electrical opening in which the spacing Ef is maximum. This maneuver takes place between times t0 and tf respectively corresponding to the moment when the two electrodes 20, 22 lose the physical contact allowing the circulation of the current by conduction, and at the instant when the two electrodes 20, 22 reach their final relative position of opening. The spacing E at a given instant may be determined as being the shortest distance separating the two electrodes 20, 22 in the insulating fluid surrounding the electrodes inside the enclosure 12. In the example illustrated, the spacing between the two electrodes 20, 22 corresponds, as long as the tube 24 is projecting, on the side of the first electrode by 20, with respect to the main body of the second electrode 22, at the spacing between the first electrode 20 and the tube 24. Of course, when the tube is received inside the main body of the second electrode 22, the spacing between the two electrodes 20, 22 corresponds to the spacing between the first electrode 20 and the main body of the second electrode. electrode 22, and remains constant even if the spacing movement of the tube 24 continues. The spacing thus corresponds to the minimum distance to be traveled for an electric arc between the two electrodes 20, 22.

In the illustrated example, the spacing movement of the two electrodes is a rectilinear movement along an axis, and the spacing corresponds to the shortest distance between the two electrodes measured along this axis.

It will be noted that the instantaneous spacing speed of the two electrodes 20, 22 corresponds to the derivative with respect to the time of the spacing between the two electrodes. The instantaneous spacing speed may therefore be different from the speed of the movement of one of the two electrodes 20, 22, for example in certain cases where the relative spacing movement is not rectilinear.

In the exemplary embodiments illustrated in FIGS. 5A to 5D, the relative opening movement of the electrodes 20, 22 can decompose into at least two steps.

An initial step of opening, fast, begins at the instant to and lasts until an end time, for example identified by the time tai in the examples of Figs. 5A to 5C. During this initial step, the two electrodes 20, 22 progressively deviate.

During the initial step, the relative movement of the two electrodes is preferably continuous, without stopping, to limit the duration of this step. The instantaneous spacing velocity of the two electrodes during the initial step can be constant, as illustrated in FIGS. 5A to 5C, or may be variable during the step as shown in FIG. 5D.

If, during this initial step of fast opening, the spacing speed is constant, or considered as such, as illustrated in FIGS. 5A to 5C, the two electrodes 20, 22 progressively deviate to a spacing value Eai, corresponding to an intermediate relative position of the two electrodes, at a first average spacing velocity VI. The first average spreading speed can, in this case of constant speed, for example be calculated as the value VI = Eal / (tai -t0). The initial step is followed by at least one stabilization step, but sometimes several, subsequent to the initial step, during which a relative movement of the two electrodes is performed at a second average lower spacing speed. at the first average speed of separation.

In the examples of Figs. 5A to 5C, the stabilization step is a step during which the spreading speed is constant and lasts for a start time tai, corresponding in this example to the end time of the initial opening step, until at an end time tbi at which the two electrodes 20, 22 occupy a relative position in which their spacing reaches a second value Ebi. During this stabilization step, the relative movement of the two electrodes takes place at an average spacing speed V2 lower than the first average spacing speed VI. The second average spacing velocity V2 may for example be calculated as the value V2 = (Ebi - Eai) / (tbi - tai).

During the stabilization step, the instantaneous spacing velocity of the two electrodes may be constant, as illustrated in FIGS. 5A to 5C, or may be variable during the step as shown in FIG. 5D. It will be noted that during the stabilization step, the two electrodes 20, 22 can be immobile with respect to each other, which corresponds to an average spacing velocity V2 of zero, which is illustrated in FIG. . 5B.

In some cases, for which the average spacing velocity V2 of the relative movement during the stabilization step is not zero, it is possible for the stabilization step to be prolonged until the two electrodes 20, 22 reach their relative opening position, in which they have the maximum spacing Ef.

However, especially in the examples illustrated in FIG. 5A and in FIG. 5B, the method comprises, after the stabilization step, at least one fast aperture tracking step, which therefore starts in the examples at time tbi end of the stabilization step, during which a movement relative to the two electrodes 20, 22 is performed at a third average spacing velocity V3 greater than the second average spacing velocity V2 during the stabilization phase. This opening continuation step may be continued until the two electrodes reach their relative opening position, in which they have the maximum spacing Ef. In this case, illustrated in particular in FIG. 5A and in FIG. 5B, the third average spacing velocity V3 can for example be calculated as the value V3 = (Ef - Ebi) / (tf - tbi). It should be noted that the third average spacing velocity V3 may be equal to, greater than or less than the first average spacing velocity V1 during the initial opening step.

However, the method may comprise, as illustrated in FIG. 5C, after an opening continuation step as described above, a secondary stabilization step during which a relative movement of the two electrodes is performed at a fourth average spacing speed V4. In the illustrated example, the secondary stabilization step lasts from a start time ta2 to an end time tb2. In this case, the fourth average spacing velocity V4 can for example be calculated as the value V4 = (Eb2 - Ea2) / (tb2 - ta2).

The fourth average spacing velocity V4 is less than the third average spacing velocity V3 during the above-described open tracking step which precedes it immediately. Of course, the third average spacing velocity V3 can for example be calculated as the value V3 = (Ea2 - Ebi) / (^ 2 - tbi).

The fourth average spacing velocity V4 may be equal to, lower than or greater than the second average velocity V2 of spacing during the first stabilization phase described above.

The fourth average spacing velocity V4 is preferably lower than the first average spacing velocity VI during the initial opening step described above.

The fourth average spacing velocity V4 may be constant as illustrated, or variable or zero during the secondary stabilization step.

It will be noted that this secondary stabilization step, if it does not consist exclusively of stopping the relative movement of the two electrodes 20, 22, could continue until the two electrodes reach their relative electrical opening position. . However, in the example illustrated in FIG. 5C, the method comprises a final opening step in which the electrodes 20, 22 reach their final relative position of opening. This final opening step can be done at an average spacing speed greater than that of the first stabilization phase and / or greater than that of the secondary stabilization phase.

Of course, it is possible to multiply the secondary stabilization steps, two secondary stabilization steps being separated by an opening continuation step during which the average spacing speed of the two electrodes is greater than the average speed of spacing of the two electrodes during the stabilization steps immediately anterior and immediately posterior.

In the examples illustrated in FIGS. 5A to 5C, the spread velocities are considered constant during the different steps. More particularly, the passage from one step to the other is easily identifiable by the fact that the variation of relative spacing speed of the two electrodes is then abrupt during the transition from one step to another, the curve of variation of the spacing of the two electrodes as a function of time exhibiting a sharp break, indicative of a discontinuity in its derived function representative of the spacing speed.

In the example illustrated in FIG. 5D, the spacing velocities of the relative movement of the two electrodes during the different steps are not constant. Furthermore, the transition from one stage to another is carried out without abrupt transition, with a progressive acceleration or deceleration. In such a case, however, it is possible to determine an average spacing speed during a stabilization step according to the following method.

A stabilization step is a step comprising at least one stabilization time interval whose duration is at least 5 times the alternating period of the alternating potential of the first electrode and corresponding to spacings of the two electrodes of between 10% and 90%. % of the final gap Ef, during which a relative movement of the two electrodes is performed at a mean stabilizing gap velocity V2 of less than 0.03 meters per second during said stabilization time interval. Within the meaning of the invention, it is understood that the beginning and the exact end of a stabilization step are not necessarily perfectly determined, but that the existence of such a step is determined by the existence of at least one stabilization time interval as defined above. At the limit, a stabilization step consists of a single stabilization time interval as defined above.

In the example illustrated in FIG. 5D, two stabilization time intervals corresponding to this definition have been illustrated, both of which belong to the same stabilization step. It will be understood that, in cases where a stabilization step has a duration greater than 5 times the alternating period of the alternating potential of the first electrode, it is actually possible to define, during the stabilization step, a plurality, even an infinity of such intervals of stabilization time successive or partially overlapping.

A first of these stabilization time intervals is illustrated which starts at time t2i and ends at time t2f, corresponding respectively to spacings E2i and E2f of the two electrodes. It has a duration T2, for example equal to 5 times the alternating period of the alternating potential of the first electrode. The mean spacing velocity of the two electrodes during this first stabilization time interval is therefore V2i = (E2f - E2O / (t2f - t2i) = (E2f - E2O / T2.

In addition, an average minimum stabilization gap velocity V2min is defined. For this, a second of these stabilization time intervals is defined and illustrated which starts at time t2imin and ends at time t2fmin, respectively corresponding to E2imin and E2fmin spacings of the two electrodes. It has a duration T2, fixed at 5 times the alternating period of the alternating potential of the first electrode. The instants t2imin and t2fmin are selected at equal time on either side of an instant t2min for which the instantaneous speed of the spacing movement of the two electrodes reaches a local minimum. The local minimum corresponds to the instant when the acceleration of the spacing is canceled by passing from a negative value to a positive value. The average spacing velocity of the two electrodes during this stabilization time interval is therefore V2min - (E2fminFalind) / (t2fmin - t2imin) - (E2fmin - Fake) / T2. This second time interval is here the one for which the average stabilizing gap velocity V2min is considered minimal. The average minimum stabilization gap velocity V2min is less than 0.03 m / s.

In the example illustrated in FIG. 5D, it is possible to define an opening step prior to the stabilization phase, and a post-opening tracking step subsequent to the stabilization phase, as being steps in which the speed of the relative movement of separation of the two electrodes passes through a local maximum, respectively at times timax and t3maX. The local maximum corresponds to the instant when the acceleration of the spacing is canceled by passing from a positive value to a negative value. The instant timax is prior to the instant of the local minimum t2min of the stabilization step. The time t3max is later than the instant of the local minimum t2min of the stabilization step. The initial step of opening comprises at least one fast opening time interval whose duration T1 is at least 1 time alternating period of the alternating potential of the first electrode, for example 1 times the period of alternation of the alternating potential of the first electrode, and during which a relative movement of the two electrodes takes place at a first average velocity of spacing VI greater than 0.05 meters per second, preferably greater than 0.1 meters per second

Furthermore, an average minimum stabilization gap velocity Vlmax is defined. For this purpose, it is possible to determine a fast opening time interval whose duration T1 is equal to 1 times the period of alternation of the alternating potential of the first electrode, by choosing times tiimax and tifmax at equal time on both sides. other of the instant timax for which the instantaneous velocity of the spacing movement of the two electrodes reaches a local maximum during the initial opening step prior to the stabilization step. Eiimax and Eifmax are the corresponding values of the spacing of the two electrodes. A first average spacing velocity VI, in this case the first average maximum spacing velocity Vlmax, during this fast opening time interval can be calculated simply according to the formula Vlmax = (Eifmax "Eiimax) / (tifmax - tlimax) = (Eifmax - Eijmax) / Tl.

Preferably, the first average maximum spacing velocity Vlmax is greater than 0.05 m / s, more preferably greater than 0.1 m / s.

An opening continuation step comprises at least one opening continuation time interval whose duration is at least 5 times the alternating period of the alternating potential of the first electrode and during which a relative movement of the two electrodes 20 , 22, 24 is carried out at an average spacing velocity V3 greater than the average minimum spacing gap velocity V2min, preferably greater than 0.03 m / s, more preferably greater than 0.05 m / s.

In addition, a mean minimum stabilization gap velocity V3max is defined. For this purpose, it is possible to determine an opening continuation time interval whose duration T3 is 5 times the alternating period of the alternating potential of the first electrode by choosing times t3jmax and t3fmax at equal time on both sides. other of the instant t3max for which the instantaneous speed of the spacing movement of the two electrodes reaches a local maximum during the post-tracking step subsequent to the stabilization step. E3jmax and E3fmax are the corresponding values of the spacing of the two electrodes. The third average maximum spacing velocity V3max, during this opening continuation time interval, can be calculated simply according to the formula V3max = (E3fmax E3jmax) / (t3fmax - t3jmax) = (E3fmax - E3jmax) / T3.

Preferably, the average maximum spacing velocity V3max during this opening continuation time interval is greater than 0.03 meters per second, preferably greater than 0.05 meters per second, more preferably greater than 0.1 meters per second.

Preferably, the minimum average stabilization gap velocity V2min, during the stabilization time interval whose duration T2 is 5 times the alternating period of the alternating potential of the first electrode and which is centered on the instant t2min for which the instantaneous speed of the spacing movement of the two electrodes reaches a local minimum, is less than 0.5 times the first average maximum spacing velocity Vlmax during the fast opening time interval, whose duration Tl is equal to 1 times the alternating period of the alternating potential of the first electrode and which is centered on the instant timax for which the instantaneous velocity of the spacing movement of the two electrodes reaches a local maximum during the initial opening step prior to the stabilization stage.

Also, preferably, the minimum average stabilizing gap velocity V2min, during the stabilization time interval whose duration T2 is 5 times the alternating period of the alternating potential of the first electrode and which is centered on the time t2min for which the instantaneous velocity of the spacing movement of the two electrodes reaches a local minimum, is less than 0.5 times the third average maximum spacing velocity V3max during the opening continuation time interval, whose duration T3 is equal to 1 times the period of alternation of the alternating potential of the first electrode and which is centered on the instant t3max for which the instantaneous velocity of the spacing movement of the two electrodes reaches a local maximum during the tracking step of opening after the stabilization step.

In cases where the method does not have a rapid aperture continuation step, the distance curve does not have a local maximum point of the subsequent spacing velocity at the local minimum point of the velocity of the motion. spacing. In this case, it can be considered that the stabilization step is completed for the relative position of opening corresponding to the maximum spacing of the two electrodes.

A similar method can be implemented for calculating the average spreading velocity for the secondary stabilization phase (s), if necessary.

It will be noted that the method developed above for determining the relevant speeds in the general case illustrated in FIG. 5D is valid for the examples of FIGS. 5A to 5C in which the speeds are constant during each of the steps.

In general, a stabilization step may be considered as a continuous period enveloping all contiguous or overlapping stabilization time intervals, whose duration (T2) is at least 5 times the period of alternation of the alternating potential of the first electrode and corresponding to spacings of the two electrodes between 10% and 90% of the final spacing (Ef), during which a relative movement of the two electrodes takes place at an average stabilization gap velocity V2 of less than 0.03 meter per second.

As understood from the foregoing, a stabilization step begins for a relative position of the two intermediate electrodes Eai between the relative position of closure of the two electrodes, which is their position of last physical contact, and the final relative position of opening. , which is their position of maximum spacing Ef. As seen above, for the case of a stabilization step at constant speed, the beginning of the stabilization step is easily identifiable. In the more general case, the beginning of the stabilization step is the beginning of the continuous period enveloping all contiguous or overlapping stabilization time intervals as indicated above. In the more general case, the end of the stabilization step is the end of the continuous period enveloping all contiguous or overlapping stabilization time intervals as indicated above. A stabilization step has, between its beginning and its end thus defined, a duration equal to at least 5 times, alternatively at least 10 times, alternatively at least 20 times the period of alternation of the electrical potential to which the first electrode is subjected. 20.

In the illustrated examples, the stabilization step begins for a spacing position Eai of the two electrodes which is distinct from the relative position of closure and the final relative position of opening of the two electrodes.

In certain alternative embodiments, a stabilization step may be triggered to correspond to predetermined relative positions of the two electrodes 20, 22, 24. In this case, the intermediate relative position Eai of the two electrodes for which a stabilization step starts is a predetermined relative position.

On the contrary, in other embodiments, a stabilization step can be triggered according to at least one operating parameter of the apparatus. Such an operating parameter may comprise, for example, geometrical parameters constituting the apparatus, and / or parameters related to the nature and / or the pressure of the surrounding gas in the envelope 12, and / or the characteristic parameters of the electrical potentials to which the apparatus is subjected, and / or spacing velocity profiles of the two electrodes. In this case, the intermediate relative position Eai of the two electrodes for which a stabilization step starts is a relative position which is determined as a function of at least this operating parameter of the apparatus. The stabilization step can thus be triggered, for example, as a function of the ignition voltage, that is to say the voltage between the two electrodes at the time of the initiation of an electric arc between the two electrodes 20, 22, 24. Alternatively, the stabilization step can be triggered, for example, at least as a function of the duration of a time interval between two electric arcs between the first and the second electrode during the movement of opening.

Indeed, in certain embodiments of the invention, during the initial opening step and / or during a step of continuing the opening, it is possible to detect a time interval between two successive electric arcs between the first and the second electrode, and then the duration of the detected time interval can be compared with a reference value above which a stabilization step is triggered.

For this purpose, it is possible to provide the cut-off apparatus with a sensor 50 capable of detecting the presence of an electric arc between the two electrodes, more particularly between the movable member 24 and the opposite electrode 20. For example, the sensor 50 may comprise an optical sensor observing the space between the two electrodes, an electric sensor in the electrical circuit, preferably close to the breaking device 10, or an electromagnetic sensor sensitive to electromagnetic fields in the enclosure. 12 generated by overvoltages occurring during arcing. The sensor 50 may also include a combination of sensors. This sensor 50 is for example connected to an electronic control unit which is able to determine a time interval between two electric arcs according to the signals sent by the sensor 50.

In the example illustrated, the electronic control and control unit 52 of the control device 42 is capable, in addition to the control and control of the actuator 48, of receiving the signals from the sensor 50 and of determining an interval time between two successive electric arcs between the two electrodes.

With such an arrangement, the electronic control and control unit 52 may be programmed to implement an opening control method of the mechanical breaking apparatus 10, the main steps of which are illustrated in FIG. 6.

In the course of a first step 100, the method may comprise an initial step "START OPEN VI" during which the electronic control and control unit 52 initiates the opening of the apparatus by controlling the motor 48 of so that it causes, via the transmission mechanism 44, 46, a rapid relative movement of the two electrodes, from the relative position of closure. The velocity profile of this movement may be, inter alia, one or the other of those illustrated in FIGS. 5A to 5D, for example a constant velocity profile at the first average velocity of spacing VI, as in Figs. 5A to 5C, or a variable speed profile as in FIG. 5D.

While this initial step 100 continues to unfold, the control and control unit 52 can trigger a step 200 of detecting a time interval Δtso between two electric arcs between the first and the second electrode. This step may comprise the reception of signals relating to the presence of an electric arc between the movable member 24 and the opposite electrode 20, due to the opening of the apparatus, delivered by the sensor 50. control and control 52 can then deduce a time interval At50 between two successive arcs detected by the sensor 50. This determination of the time interval Atso can be initiated from the beginning of the initial step 100, or some time after for example after the expiry of a delay time, or beyond a threshold value of the spacing of the two electrodes. As soon as the detection step 200 makes it possible to determine successive time intervals between two successive arcs, the control and control unit 52 can, in a comparison step 300, compare these time intervals At5o, measured by means of FIG. sensor 50, at a reference time interval Atref · This reference time interval Atref may be a value stored in the control and control unit 52. It may be a value chosen in a table according to operating parameters 10 alternatively, the reference value Atref may be a value calculated according to one or more operating parameters of the switchgear 10 or the installation.

If the comparison step 300 determines that the duration of the measured time interval Atso becomes greater than the reference value Atref, the control and control unit 52 can trigger a stabilization step 400, "START STAB V2" , subsequent to the initial step, during which a relative movement of the two electrodes is performed according to a speed profile in which the speed is reduced. The velocity profile of this movement may be, inter alia, one or the other of those illustrated in FIGS. 5A to 5D, for example a constant velocity profile at a mean stabilization gap velocity V2 lower than a first constant spacing velocity VI, as in Figs. 5A to 5C, or a variable speed profile as in FIG. 5D. The control and control unit 52 then modifies the commands sent to the motor 48 to slow the speed of the spacing movement of the two electrodes.

The duration of the stabilization step may be predetermined, for example by a time predetermined in time or by a threshold value of the spacing of the two electrodes. This duration may alternatively be determined as a function of one or more operating parameters of the switching device, for example the geometrical parameters constituting the device or the characteristic parameters of the electrical potential or potentials to which the device is subjected, in particular in the form of selecting values in a table or in the form of calculation according to these parameters.

In this embodiment, it is also provided, after the stabilization step, at least one opening continuation step 500, "START OPEN V3" during which a relative movement of the two electrodes takes place at a distance of average spacing speed greater than the second average spreading speed. The opening continuation step 500 could continue unconditionally until both electrodes have reached their relative electrical opening position in which they reach their final gap, then triggering a stop step 700 "STOP" of control device 42.

However, in the illustrated embodiment, during the opening continuation step 500, it is envisaged to carry out a control step 600, "TEST", during which the signals delivered by the sensor 50 are used to detect the possible occurrence of an electric arc between the two electrodes.

If such an arc is detected, the method may advantageously provide either to directly trigger a secondary stabilization step by returning the process directly to the stabilization step 400 described above, or to return the method to the comparison step 300 described. upper. Thus, the triggering of a secondary stabilization step is determined at least as a function of the detection of an electric arc between the first and the second electrode during an opening continuation step.

In any case, when the two electrodes reach their final spacing, the method triggers a stopping step 700 of the control device 42.

Of course, other variants of the process can be envisaged, in particular according to the methods described with reference to FIGS. 5A to 5D.

The end of the stabilization step can also be determined, for example, as a function of the detection of the presence of an electric arc between the two electrodes, this detection being possible by means of the sensor 50. For example, it is possible to provide that the stabilization step is completed after the lapse of a predetermined period of time following a last electric arc detected between the two electrodes 20, 22, 24. It is therefore possible, after the lapse of this period of time, trigger a continuation of opening step.

Preferably, the positioning of a stabilization step in the process, for example defined by the start times tai, ta2 and the end tbi, tb2 of a stabilization step, in particular of the first stabilization step, are predetermined, chosen or calculated so that, during the stabilization step, the electrodes 20, 22 occupy at least one relative position of last arc for which: - there is an electric potential value of the first electrode which creates, for this position, and for an earlier potential value of the second electrode, an electric arc between the two electrodes, and - the electric arc brings the second electrode to a final potential for which the electrical potential difference between the first electrode and the second electrode is less than the minimum dielectric strength between the electrodes for said position.

The minimum dielectric strength between the electrodes for said position corresponds to the voltage between the two electrodes which would cause, for said position, the initiation of an electric arc between the two electrodes 20, 22, 24. It can be determined for a installation, by a test campaign.

If such a position is not found, it is possible that at least one secondary stabilization step is necessary until this effect is achieved.

In other words, this position is a position for which, given the operating parameters of the switchgear in the installation, the potential difference between the first and the second electrode will, after possibly several changes in values. due to successive electric arcs caused by the alternating variations of the potential of the first electrode, reaching a final value beyond which the potential of the second electrode will no longer vary during the subsequent relative movement of opening of the two electrodes until that they reach their relative position of electrical opening. Thanks to the invention, stabilization of the potential of the floating potential electrode is obtained for the potential as close as possible to the minimum potential that may exist, which depends on the constituent parameters of the disconnector.

In general terms, the start and end times of the stabilization step, and the spacing of the two electrodes to which these two instants correspond, are chosen so that, during a stabilization step, the electrodes occupy at least one relative position for which the spacing value of the electrodes is between 10% and 90% of the spacing value of the electrodes in the final open position.

Simulations and tests have shown that, for certain configurations, satisfactory results are obtained if, during the stabilization step, the electrodes occupy at least one relative position for which the spacing value of the electrodes is between 10% and 50%, more preferably between 10% and 30% of the spacing value of the electrodes in a final open position. For other configurations, satisfactory results are obtained if, during the stabilization step, the electrodes occupy at least one relative position for which the spacing value of the electrodes is between 40% and 90%, more preferably between 60% and 90%. % and 90% of the gap value

Preferably, a stabilization step has a duration equal to at least 5 times the period of alternation of the alternating electric potential to which the first electrode is subjected, in this case the period of alternation of the voltage of the voltage source, preferably at least 15 times the alternating period of the alternating electric potential to which the first electrode is subjected, so as to increase the probability that the last electric arc will occur during the stabilization step.

Simulations and tests have shown that a stabilization step may have a duration of less than 75 times the alternating period of the alternating electric potential to which the first electrode is subjected, preferably less than 50 times the alternation period of the potential. AC power to which the first electrode is subjected. By thus limiting the duration of a stabilization phase, the total time of the opening movement of the breaking device between the relative electrical closing position and the relative electrical opening position of the two electrodes is reduced. However, even observing this time limit, it is generally found that the last electric arc is reached during the stabilization step.

Simulations and tests have shown that the second average spreading speed can be chosen so that the rate of increase of the maximum dielectric strength of the apparatus, caused by the increase of the spreading value, increases at a speed less than 1.0 pu / s, preferably less than 0.5 pu / s, where 1 pu is the peak value of the alternating electric potential to which the first electrode is subjected, in this case the peak value of the voltage of the source of tension.

By adopting the above recommendations for the position of the stabilization step, for its duration, and for the maximum rate of increase of the maximum dielectric strength of the apparatus, simulations have shown that the electrical potential of the second electrode when the two electrodes reach their final relative opening position is less than 0.5 pu.

Figs. 7A to 7D illustrate an embodiment of a mechanical circuit breaking device which is identical to that described above with reference to FIGS. 1 to 3, but in which the transmission mechanism 44, 46 connecting the actuator 48 to at least one of the electrodes, in this case to the tube 24 of the second electrode 22, is configured to implement an exemplary embodiment of FIG. a method according to the invention, in a completely mechanical manner.

This mechanism similarly comprises a lever 46 which is rotated by the actuator 48 around an axis A2 perpendicular to the axis A1 of the movement of the electrodes. At the end of the lever 46 which is opposite to the axis of rotation A2, the rod 44 is articulated on the lever 46 about an axis A3 parallel to the axis A2 by the kiss of a hinge pin 54 A3 axis which is received in an L-shaped groove 56 arranged in the lever 46, in a plane perpendicular to the axes A2 and A3. The L-groove 56 has a long limb 56b of dead stroke and a short limb 56a of initial training, the two branches forming between them an angle of about 90 degrees. The two branches 56a, 56b each extend from a common intersection to a branch end end.

In the position of FIG. 7A, which corresponds to the relative position of electrical closure, it is understood that the lever 46 is oriented so that the short branch 56a is oriented towards the front, in the direction of the first electrode 20, with respect to its intersection with the long branch 56b. The hinge pin 54 is received at the bottom end of this short branch 56b.

During the opening movement, the lever 46 is driven by the actuator 48, in this case in a clockwise direction, considering the figures. The hinge pin 54 being received at the bottom end of the short branch 56a of the groove, it is driven by this end end, towards the rear, so as to cause the spacing of the second electrode 22, 24 to which it is connected by connecting rod 44.

Fig. 7B illustrates a position of the transmission mechanism for which the orientation of the short branch of the groove 56 is substantially perpendicular to the connecting rod 44. From this position, under the effect of the forces and under the effect of gravity, the hinge pin 54 escapes from the bottom end of the short branch 56a of the groove towards the intersection with the long branch 56b of this groove. Note that the long branch 56b of the groove is then substantially parallel to the axis A1 of the opening movement.

Between the positions of Figs. 7B and 7C, the lever 46 continues its rotational movement around the axis A2, but this rotational movement does not cause displacement of the rod 44, let alone the second electrode 22, 24. Indeed, between these two positions, the hinge pin 54 between the rod 44 and lever 46 can move freely in the long branch 56b of the groove 56, from the intersection towards its bottom end, it reaches for the position of Figure 7C . It can thus be seen that between the positions of FIGS. 7B and 7C, the lever 46 has continued its rotational movement while the tube 24 of the second electrode 22 has not been moved and therefore maintains a constant spacing relative to the first electrode.

When the lever 46 continues its rotational movement about the axis A2 relative to the position of Figure 7C, the hinge pin 54 being received at the bottom end of the long branch 56b of the L-shaped groove 56 it can be seen that the connecting rod 44, and therefore the second electrode 22, 24, resumes its opening movement until reaching the relative position of electrical opening illustrated in FIG. 7D.

With a control device as illustrated, it is therefore understood that a constant speed rotation movement of the lever 46 about the axis A2, for example caused by a motor 48 driven at constant speed, results in a movement of the second electrode 22, 24 which comprises a stopping phase between the positions of FIGS.

7B and 7C. In this way, the apparatus illustrated in Figs. 7a to 7D allows, by mechanical means, to cause a movement of the electrodes whose movement profile is similar to that illustrated in FIG.

5B, in that it makes it possible to ensure a stabilization step with a stop of the relative movement of the two electrodes, between an initial opening step, between the positions of FIGS.

7A and 7B, and a step of continuation of opening between the positions of FIGS.

7C and 7D. The invention is not limited to the examples described and shown because various modifications can be made without departing from its scope.

Claims (24)

1 - Method for controlling the opening of a mechanical breaking device (10) in an AC high-voltage electrical circuit, of the type comprising two electrodes of which a first (20) is subjected to an alternating electric potential having a period of alternation , and a second (22, 24) is electrically isolated from any voltage source and any electrical mass, the two electrodes of the mechanical apparatus being movable relative to each other in a controlled opening movement between a relative electrical closing position, in which they establish a nominal electrical connection of the apparatus, and at least one final electrical opening relative position in which the two electrodes are spaced apart from each other final distance (Ef), characterized in that the method comprises: an initial opening step comprising at least one fast opening time interval whose duration (Tl) is at least ins 1 times the alternating period of the alternating potential of the first electrode and during which a relative movement of the two electrodes is performed at a first average spacing velocity (VI) greater than 0.05 meters per second, preferably greater than 0.1 meters per second; at least one stabilization step, subsequent to the initial opening step and comprising at least one stabilization time interval whose duration (T2) is at least 5 times the period of alternation of the alternating potential of the first electrode; and corresponding to spacings of the two electrodes (20, 22, 24) between 10% and 90% of the final gap (Ef), during which a relative movement of the two electrodes (20, 22, 24) is effected at an average stabilizing gap velocity (V2) of less than 0.03 meters per second. 2 - Process according to claim 1, characterized in that the method comprises, after the stabilization step, at least one opening continuation step comprising at least one opening continuation time interval whose duration is at least 5 times the period of alternation of the alternating potential of the first electrode and during which a relative movement of the two electrodes (20, 22, 24) is carried out at an average spacing speed (V3) of greater than 0.03 meters per second preferably greater than 0.05 meters per second, more preferably greater than 0.1 meters per second. 3 - Process according to claim 2, characterized in that the method comprises, after an opening continuation step, a secondary stabilization step comprising at least a secondary stabilization time interval whose duration is at least 5 times the period alternating potential of the alternating potential of the first electrode, during which a relative movement of the two electrodes (20, 22, 24) is carried out at an average spacing speed (V4) of less than 0.03 meters per second. 4 - Method according to one of the preceding claims, characterized in that the method comprises a final opening step in which the electrodes (20, 22, 24) reach their final relative position of opening (Ef). 5 - Method according to one of the preceding claims, characterized in that a stabilization step begins for an intermediate relative position (Eai) of the two electrodes (20, 22, 24) between the relative position of closure and the final relative position of opening (Ef), and distinct from the relative position of closure and the final relative position of opening (Ef). 6 - Method according to one of the preceding claims, characterized in that a stabilization step is triggered to correspond to a predetermined relative position of the two electrodes (20, 22, 24). 7 - Method according to one of the preceding claims, characterized in that a stabilization step is triggered according to at least one operating parameter of the apparatus (10). 8 - Method according to one of the preceding claims, characterized in that a stabilization step is triggered at least as a function of the duration of a time interval between two electric arcs between the first (20) and the second (22). , 24) electrode during the opening movement. 9 - Method according to one of the preceding claims, characterized in that, during the initial opening step, a time interval (Atso) is detected between two electric arcs between the first (20) and the second (22, 24), and comparing the duration of the time interval (At 50) with respect to a reference value (Atref) above which a stabilization step is triggered. 10 - Method according to one of the preceding claims, characterized in that a stabilization step is triggered at least according to the voltage between the two electrodes at the time of the initiation of an electric arc between the two electrodes (20). , 22, 24). 11 - Method according to claim 2, characterized in that an opening continuation step is triggered after the lapse of a predetermined period of time following a last electric arc detected between the two electrodes (20, 22, 24) . 12 - Process according to claim 3, characterized in that the triggering of a secondary stabilization step is determined at least according to the detection of an electric arc between the first and the second electrode during a tracking step opening. 13 - Method according to one of the preceding claims, characterized in that, during a stabilization step, the electrodes (20, 22, 24) occupy at least one relative position of last arc for which: there is an electric potential value of the first electrode (20) subjected to an alternating electric potential which creates, for this position, and for an anterior potential value of the second electrode (22, 24), an electric arc between the two electrodes, and - the arc electric causes the second electrode (22, 24) to have a final potential for which the electrical potential difference between the first electrode (20) and the second electrode (22, 24) is less than the minimum dielectric strength between the electrodes for said position . 14 - Method according to one of the preceding claims, characterized in that, during the stabilization step, the electrodes (20, 22, 24) occupy at least one relative position for which the spacing value of the electrodes is between 10% and 50%, more preferably between 10% and 30% of the spacing value (Ef) of the electrodes in a final open position. 15 - Method according to one of the preceding claims, characterized in that, during the stabilization step, the electrodes (20, 22, 24) occupy at least one relative position for which the spacing value of the electrodes is between 40% and 90%, more preferably between 60% and 90% of the spacing value (Ef) of the electrodes in a final open position 16 - Method according to one of the preceding claims, characterized in that a stabilization step comprises at least one stop of the relative movement of the two electrodes (20, 22, 24). 17 - Method according to one of the preceding claims, characterized in that a stabilization step consists of stopping the relative movement of the two electrodes (20, 22, 24). 18 - Method according to one of the preceding claims, characterized in that a stabilization step has a duration equal to at least 5 times, alternately at least 10 times, alternately at least 20 times the period of alternation of the electric potential at which the first electrode (20) is subjected. 19 - Method according to one of the preceding claims, characterized in that a stabilization step has a duration less than 75 times the alternating period of the electrical potential which is subjected to the first electrode (20), preferably less than 50 times the period of alternation of the electric potential to which the first electrode is subjected. 20 - Method according to one of the preceding claims, characterized in that the second average spacing speed (V2) is chosen such that the rate of increase of the minimum dielectric strength of the device, generated by the increasing the distance value, increases at a speed below 1.0 pu / s, preferably below 0.5 pu / s, where 1 pu is the peak value of the electrical potential to which the first electrode (20) is subjected compared to To the earth. 21 - Method according to one of the preceding claims, characterized in that the electric potential of the second electrode when the two electrodes reach their final relative opening position is less than 0.5 pu, where 1 pu is the peak value of the electrical voltage to which the first electrode (20) is subjected to earth. 22 - Electrical installation comprising an apparatus for mechanical breaking (10) of an alternating high-voltage electrical circuit, of the type comprising two electrodes of which a first (20) is subjected to an alternating electric potential and of which a second (22, 24) is electrically isolated from any source of voltage and any electrical mass, the two electrodes (20, 22, 24) of the mechanical apparatus being movable relative to each other in an opening movement controlled by a control (42), between a relative electrical closing position, in which they establish a nominal electrical connection of the apparatus, and at least one relative electrical opening position in which the two electrodes are spaced apart from each other , characterized in that the control device (42) is configured to implement a control method according to any one of the preceding claims. 23 - Electrical installation according to claim 22, characterized in that the control device (42) comprises an actuator (48) for controlling the relative movement of the electrodes (20, 22, 24), and a controller which controls the actuator, the controller being programmed to implement the method of any one of claims 1 to 21. 24 - Electrical installation according to claim 22, characterized in that the control device comprises an actuator (48) for controlling the relative movement of the electrodes (20, 22, 24) by means of a transmission mechanism (44, 46) connecting the actuator (48) to at least one of the electrodes, the transmission mechanism (44, 46) being configured to implement the method of any one of claims 1 to 21.