Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H39/00—Switching devices actuated by an explosion produced within the device and initiated by an electric current
  • H01H39/006—Opening by severing a conductor
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H9/00—Details of switching devices, not covered by groups H01H1/00 - H01H7/00
  • H01H9/0072—Details of switching devices, not covered by groups H01H1/00 - H01H7/00 particular to three-phase switches

Definitions

• Cut-off device for equipping a three-phase circuit
• the invention relates to a cut-off device for equipping a three-phase circuit and a secure electrical system comprising in particular a three-phase circuit connected to such a cut-off device. Protection of three-phase circuits can currently be ensured by positioning fuses on each of the phases. These fuses allow the power to be cut off if a high current occurs for a sufficient time, their use is reliable in the case of faulty faults with high fault currents. However, for currents slightly above their rated current, these fuses may have a relatively long cut-off time or even an incomplete cut-off. An incomplete or too late cut can lead to unacceptable damage to the electrical system and in particular to an electrical device powered by the three-phase circuit. It is therefore desirable to improve the quality of the cut made when a malfunction occurs to improve the safety and life of electrical systems incorporating a three-phase circuit.
• the invention proposes, according to a first aspect, a cut-off device intended to equip a three-phase circuit, comprising at least:
• a first pressurizing chamber in communication with an output of said pyrotechnic initiator
• each of said conductive portions being intended to be connected to a phase of a three-phase circuit
• a movable cut-off element separating the first chamber from the second chamber and having at least one relief formed of an electrically insulating material, the said at least one relief facing conductive portions,
• the pyrotechnic initiator being configured to switch the cut-off device from a first current-flow configuration to a second current-breaking configuration, the movable cut-off element being moved to the conductive portions to simultaneously break the current three conductive portions per impact with the relief when passing from the first to the second configuration.
• the pyrotechnic initiator is configured to produce a pressurizing gas to pressurize the first chamber.
• the pressurizing gas exerts pressure on the movable cutoff member to move it.
• the movable cut-off element thus set in motion is configured to break simultaneously the three conductive portions during the impact of the latter with the relief.
• the breaking device is connected to a three-phase circuit, the breaking of the conductive portions makes it possible to simultaneously cut the electric current flowing in each of the three phases of the circuit.
• phase of the three-phase circuit is meant, unless otherwise stated, the electrical conductor corresponding to one of the three phases of the three-phase circuit.
• the invention therefore proposes a cut-off device enabling a reliable electrical break to be made quickly in a three-phase circuit when a malfunction occurs.
• the fact of cutting the current by mechanical breaking of the conductive portions improves the quality of the cut with respect to a cut made by simple displacement of conductive portions.
• the breaking device according to the invention has the advantage of simultaneously cutting the current flowing in each of the three phases of the three-phase circuit. This feature advantageously makes it possible to improve the security and the lifetime of the system by avoiding the situation where only one phase is cut off while the other two remain on, a situation that can be encountered in the fuse devices of the prior art and which can lead to damage to the electrical system.
• the present invention also relates to a secure electrical system comprising at least:
• a secure power supply system comprising:
• a cutoff device as described above, a three-phase supply circuit connected to the breaking device, each of the conductive portions being connected to a phase of the three-phase circuit, and
• control element of the electrical system configured to actuate the initiator when the value of an operating parameter of the electrical system reaches a predetermined value
• the control element makes it possible to actuate the initiator, and thus cut off each phase of the three-phase circuit, when a malfunction occurs in the electrical system.
• the operating parameter may be relative to the power system or the electrical device.
• the operating parameter can be an electrical parameter, such as the intensity of a current, or a non-electrical physical parameter, such as pressure or temperature.
• control element may be connected to the three-phase circuit and configured to actuate the pyrotechnic initiator when the intensity of the electric current flowing in at least one of the phases exceeds a predetermined value.
• said control element may comprise at least one current measuring device configured to measure the intensity of the current flowing in at least one of the phases and to actuate the initiator when the measured intensity exceeds the predetermined value.
• said control element may comprise at least one fuse connected to one of the phases in series with the cut-off device, the initiator being connectable across said fuse, said fuse being configurable to disconnect the fuse. phase when the intensity of the current passing through it exceeds the predetermined value and to thereby actuate the initiator.
• the fuse is on, the voltage across the fuse relatively low and the current flowing through the ignition device of the pyrotechnic initiator is low enough not to actuate the latter.
• the voltage at its terminals increases and therefore the intensity in the ignition device increases, thus enabling the pyrotechnic initiator to be actuated and the three phases to be cut simultaneously.
• the implementation of the cut-off device makes it possible to very significantly improve the safety of fuse power supply systems insofar as it makes it possible to ensure the realization of a complete cut and thus to avoid situations where the fuse does not completely cut the phase or in which at least one phase remains pass after cutting another phase.
• At least one resistor may be present in series on the line connecting the ignition device of the initiator to one of the terminals of the fuse.
• Such an embodiment advantageously makes it possible to avoid the degradation of the ignition device by the current flowing in the latter when the fuse is tripped.
• control element can be configured to actuate the pyrotechnic initiator when an operating parameter of the electrical device reaches a predetermined value.
• control element may be configured to actuate the pyrotechnic initiator when the temperature of the electrical device or the pressure of a portion of the electrical device exceeds a predetermined value.
• the present invention also relates to a vehicle comprising at least one secure electrical system as described above.
• vehicle can for example be an aircraft, a train or an automobile.
• the present invention also relates to an installation comprising at least one secure electrical system as described above.
• the electrical device may for example be a train engine.
• the electrical device may be a heat pump or a power plant.
• FIG. 1 represents a section of a breaking device according to the invention in the first configuration
• FIG. 2 is an exploded view showing various elements constituting the device of FIG. 1,
• FIG. 3 is a perspective view of the cut-off device of FIG. 1 ready to be connected to a three-phase circuit
• FIG. 4 schematically represents an example of a secure electrical system according to the invention
• FIG. 5 schematically represents an alternative of a secure electrical system according to the invention
• FIG. 6 schematically represents another variant of a secure electrical system according to the invention.
• FIGS. 7A to 7C illustrate the breaking of the current produced by the device of FIG. 1. Detailed description of embodiments
• FIG. 1 is a sectional view of a cut-off device 1 according to the invention in the first configuration, that is to say in a configuration in which an electric current (arrow I) can flow in the phases of the circuit three-phase and in the conductive portions 8.
• the cut-off device 1 comprises a pyrotechnic initiator 3 comprising an ignition device 9 provided with two electrical conductors 5 (only one of these conductors being shown in FIG. 1, the two conductors 5 being visible in Figures 2 and 3).
• the pyrotechnic initiator 3 further comprises a pyrotechnic charge 4.
• the pyrotechnic charge 4 may be in the form of one or more monolithic blocks. Alternatively, the loading 4 may be in granular form.
• the electrical conductors 5 are connected to a control element (not shown in FIG. 1) which makes it possible to actuate the combustion of the pyrotechnic charge 4 in order to produce a gas for pressurizing. Examples of control elements that can be used in the context of the present invention will be described below.
• the device 1 comprises a body 11 inside which are present the first 7 and the second 12 chambers.
• the body 11 may for example be formed of a thermoplastic or thermosetting material.
• the pyrotechnic initiator 3 comprises a seal 6 of elastically deformable material bearing on an inner wall 14 of the body 11.
• part of the ignition device 9 is, in the illustrated example, housed in a collar 23 of the body 11.
• the body 11 further has two through channels 11a, each of the conductors 5 extending in a separate channel 11a.
• the first chamber 7 constitutes a pressurizing chamber and is in communication with an output S of the pyrotechnic initiator 3.
• the pyrotechnic initiator 3 is configured to pressurize the first chamber 7.
• the pyrotechnic charge 4 is present in the first chamber 7. However, it is not beyond the scope of the invention when this charge is present outside the first chamber as the latter remains in communication with an output of the pyrotechnic initiator.
• Three portions electrically conductive 8 are present in the second chamber 12 (see Figures 1 and 3 in particular). The ends of the conductive portions 8 protrude from the body 11 in the illustrated example. These conductive portions 8 are, in the illustrated example, in the form of tabs.
• the conductive portions 8 may for example be copper.
• the conductive portions 8 are present on a support 18.
• the support 18 has, in the illustrated example, a drawer structure intended to be engaged in an opening 22a of the side wall 22 of the body 11.
• the support 18 defines a relief in hollow 20 located below the conductive portions 8 when the device 1 is in the first configuration.
• the conductive portions 8 are spaced from each other by a non-zero distance.
• the support 18 has grooves 19 in which are housed the conductive portions 8.
• Each of the conductive portions 8 is connected to a separate phase 10 of the same three-phase circuit. This connection can for example be performed by welding.
• the ends of each of the conductive portions 8 are connected to a phase 10 of the three-phase circuit.
• the device 1 further comprises a movable cutting element 15 formed of an electrically insulating material, for example polyetheretherketone (PEEK GF40) or polyphenylene sulphide (PPS).
• the cutoff element 15 sealingly separates the first chamber 7 from the second chamber 12.
• the cutoff element 15 is located between the first 7 and the second 12 chambers.
• the cutoff element 15 has at least one relief 17 facing the conductive portions 8.
• the cutoff element 15 has a seal 16 formed of an elastically deformable material which bears on a side wall 22 of the body 11.
• the side wall 22 surrounds the first 7 and second 12 chambers.
• the relief 17 is in the form of a portion of extra thickness.
• the cutoff element 15 has a single relief 17 intended to simultaneously break the three conductive portions 8.
• the cutoff element comprises a plurality of reliefs.
• the cutoff element may thus comprise three reliefs each facing a distinct conductive portion.
• the invention is not limited to a particular form for the distal end 17b or reliefs 17 as the relief or reliefs 17 are able to break the conductive portions 8 by impact with the latter.
• the distal end 17b of the relief or reliefs 17 may thus be for example present a flat shape as illustrated or a pointed or rounded shape.
• the breaking element 15 is configured to move along the axis of displacement X following the actuation of the pyrotechnic initiator 3. When the device 1 is in the first configuration, the relief recessed 20, the conductive portions 8 and the relief 17 are superimposed along the axis X.
• the body 11 is overmoulded on the pyrotechnic initiator 3.
• the cutoff element 15 is then inserted by force through the bottom 25 which is situated on the side opposite the neck 23.
• the cutting element 15 has a positioning relief 26, here in the form of a notch, intended to cooperate with a relief present on the inner wall of the body. This cooperation makes it possible to block in rotation the breaking element 15 and thus to avoid that the latter turns around the axis X when the first chamber 7 is pressurized by the pyrotechnic initiator 3.
• the conductive portions 8 are placed in the grooves 19 of the support 18.
• the support 18 is then inserted through an opening 22a of the side wall 22 of the body 11 transversely relative to the axis of displacement X.
• the cut-off device 1 illustrated in FIG. 3 is thus obtained which is ready to be connected to a three-phase circuit for example by welding the phases on each of the conductive portions 8.
• FIG. 4 shows a first example of a secure electrical system 30 according to the invention.
• the secure electrical system 30 comprises a secure power supply system 2 connected to an electrical device 31 intended to be powered by this power supply system 2.
• the power supply system 2 comprises an electric generator G and three phases 10 connected thereto. generator G.
• the generator G may for example be an alternator.
• the generator G can be connected to a heat engine such as an internal combustion engine or a turbojet engine. Alternatively, the generator G may be part of an installation such as a power plant producing an alternating current.
• the cut-off device 1 is connected to the phases 10 as detailed above.
• the cut-off device 1 is connected in series with the generator G and the electrical device 31.
• the cut-off device 1 is present between the generator G and the electrical device 31.
• the generator G is present upstream of the cut-off device 1 and the electric device 31 is present downstream of the cut-off device 1.
• the terms "upstream” and “downstream” are here used with reference to the meaning of the electrical current in the three-phase circuit (arrow I).
• the power system 2 further comprises a control element of the electrical system 33 configured to actuate the initiator 3 when the value of an operating parameter of the electrical system reaches a predetermined value.
• the control element 33 is connected to each of the phases 10.
• the control element 33 is furthermore connected to the conductors 5 in order to allow the actuation of the ignition device 9 to be activated. the initiator 3.
• the control element 33 constitutes a device for measuring the electric current configured to measure the intensity of the current flowing in each of the phases 10 and to actuate the initiator 3 when the intensity measured in at least one of the phase 10 exceeds the predetermined value. By actuating the initiator 3, the control element 33 controls the cut-off of the electric current flowing in the three-phase circuit in order to guarantee the safety of the electrical system 30.
• FIG. 5 shows a variant of an electrical system 30 'according to the invention.
• the control element 37 is configured to actuate the pyrotechnic initiator 3 when an operating parameter of the electric device 31 reaches a predetermined value.
• the control element 37 comprises for example a temperature sensor configured to measure the temperature of the electric device 31.
• the control element 37 may comprise a pressure sensor configured to measure the pressure of a part of the electrical device 31.
• the control element 37 can be configured to actuate the pyrotechnic initiator when the temperature of the electric device 31 or the pressure of a part of said device 31 exceeds a predetermined value and this in order to guarantee the safety of the system 30 'when a malfunction is observed.
• the pyrotechnic initiator comprises three ignition devices 9 ', one fuse 40 being connected to each 10 phases in series with the device of cut.
• Each of the ignition devices 9 ' is connected to the terminals of a separate fuse 40.
• an electrical current of an intensity greater than the predetermined value passes through one of the phases 10, the resistance at the terminals of the fuse 40 associated with this phase increases, thereby generating a sufficient potential difference across the fuse 40 in order to actuate the device ignition 9 'connected to this fuse and thereby cut the electric current.
• the cut-off device makes it possible to very significantly improve the safety of fused power supply systems insofar as it makes it possible to ensure the realization of a complete break and to avoid situations where the fuse does not completely cut off.
• the electrical systems 30, 30 'and 30 "that have just been described can be mounted in a vehicle such as an aircraft or a train or be present in an industrial installation.
• the device 1 is initially in the first configuration in which an electric current (arrow I) can flow in the phases of the three-phase circuit and in the conductive portions 8.
• the breaking element 15 is in a first position, said high position.
• the pyrotechnic initiator is actuated by the control element when a malfunction occurs.
• the actuation of the pyrotechnic initiator 3 makes it possible to carry out the combustion of one or more pyrotechnic charges 4 in order to generate a combustion gas (arrows F) which will pressurize the first chamber 7 (see FIG. 7A). This pressurization of the first chamber 7 moves the cut-off element 15 towards the conductive portions 8.
• the movable cut-off element 15 is configured not to be broken during the pressurization of the first chamber 7 by the pyrotechnic initiator .
• the cut-off element 15 is configured to move without deforming during the passage of the device 1 from the first configuration to the second configuration.
• the breaking element 15 is driven in a translational movement along the X axis towards the conductive portions 8 during the transition from the first configuration to the second configuration.
• the movement of the cut-off element 15 does not include a component of rotation about the X axis during the passage from the first to the second configuration.
• the breaking element 15 simultaneously impacts the three conductive portions 8 and thus breaks the latter (see FIGS. 7B and 7C).
• the cutoff element is configured as illustrated to simultaneously impact the three conductive portions 8 transversely, for example perpendicularly, to the direction of flow of electric current in these portions 8.
• the relief 17 is housed in the embossed relief 20 of the support 18 when the device 1 is in the second configuration, the relief 17 thus abuts on the bottom of the recessed relief 20.
• the breaking element 15 is in a second position, said low position and the current is cut.
• the device according to the invention can advantageously make it possible to cut the current particularly fast, for example in about 0.2 ms.
• a maintenance operation may be performed after the three-phase circuit has been cut in order to remove the breaking device in the second configuration and replace it with a cut-off device in the first configuration.
• the power supply of the electrical device by the three-phase circuit is then resumed.

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ID=55971082

Family Applications (1)

Country Status (3)

Cited By (1)

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Family Cites Families (4)

• 2015
  • 2015-12-15 FR FR1562343A patent/FR3045204B1/fr active Active
• 2016
  • 2016-12-14 EP EP16820004.6A patent/EP3391402B1/de active Active
  • 2016-12-14 WO PCT/FR2016/053387 patent/WO2017103443A1/fr unknown

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