FR2503929A1 - AUTOMATIC LOAD INTERRUPTION PROCESS AND AUTOMATIC LOAD INTERRUPTER FOR CARRYING OUT SAID METHOD - Google Patents

Abstract

The method, which can be implemented by means of an automatic load switch (circuit breaker) for automatic load switching, comprises the main current being allowed to pass through a contact system (1) and an emergency signal being emitted by a transmitter (15, 16) for an emergency. At the same time as the emergency report, an additional current is produced, which is produced in the form of a pulse in a pulse power source (19), the magnitude and duration of which pulse are sufficient to open contacts (4, 5; 6, 7) in an emergency and which pulse is passed through the contact system (1). Mechanical forces for displacing and fixing this contact (5, 7) are then developed by an assembly (18) for displacing and fixing a contact.

Description

METHOD FOR AUTOMATICALLY INTERRUPTING THE LOAD AND
AUTOMATIC CHARGE SWITCH
FOR THE IMPLEMENTATION OF THIS PROCESS
The present invention relates to electrical engineering and, more specifically,
automatic load interruption procedures as well as switches
automatic charging for the implementation of these methods.

This invention can be successfully used for device protection
reils consumers of electricity sensitive to overcurrents, in particular, thyristor converters.

 The current progress of electrical engineering is characterized by a very rapid development of the technique of power converters. Installations with semiconductor converters, that is to say, with thyristors and diodes, are very sensitive to loads - and to protect them, automatic switches are required with rapidity and power. protection against very high overcurrents.

 An automatic charge interruption process is known (for example, the USSR author's certificate No. 296172 of 1971) consisting in passing the charge current through a contact system to create electrodynamic forces opening the contacts of at least one contact torque of the contact system, to issue an alarm signal and to create mechanical forces to move and fix one of the contacts of this pair of contacts.

 An automatic load switch is known (see, for example, the above-mentioned URUS author's certificate comprising a contact system having at least one pair of contact elements and at least one electrically connected electrodynamic current limiter. between them, at least one critical overcurrent detector electrically connected to the pair of contact elements of the contact system. a displacement and fixing block for the contact mechanically connected to the pair of contact elements of the contact system and to the critical surge detector, and at least one arc extinguisher for deflecting and extinguishing the electric arc between the elements of the pair of contact elements.

 However, in this method and in the switch intended for its implementation, the notable inertia of the displacement and contact fixing block does not make it possible to cut the load at the very moment when the damage situation manifests (the critical overcurrent), which hinders the limitation of the current and leads to an extension of the interruption time.

 In addition, to open the contact elements of the contact pair using an electrodynamic current limiter, the charging current must increase to a sufficient value, which also hinders the current limitation and leads to an extension of the duration of interruption.

 The object of the invention is to provide a method for automatic interruption of the charge comprising an additional operation which makes it possible to reduce the duration of interruption by simultaneously improving the current limitation and allowing the realization of an automatic switch of the charge. operating according to this process, having auxiliary blocks which make it possible to reduce the duration of interruption by simultaneously improving the current limitation.

 According to the invention, the method for automatically interrupting the charge consists in passing the charging current through a contact system to create electrodynamic forces opening the contacts of at least one pair of contacts of the contact system, to be sent an alarm signal and to create mechanical forces to move and fix one of the contacts of this pair of contacts, and said method is characterized in that when the alarm signal is issued, a current is created auxiliary, in the form of a pulse whose value and duration are sufficient to open the contacts at the very moment when a critical overcurrent appears, this current passing through the contact system.

 Preferably, the auxiliary current, when it passes through the contact system, is added to the charging current.

 For the implementation of the above method, the invention also provides an automatic load switch comprising a contact system comprising at least one pair of contacts as well as at least one electrodynamic current limiter electrically coupled, at least one critical surge detector electrically connected to the pair of contacts of the contact system, and a contact displacement and fixing block, mechanically linked to the pair of contacts of the contact system and to the critical overcurrent holder, and at least one arc extinguisher for deflecting and extinguishing the electric arc arising between the contacts of the pair of contacts, said switch being characterized in that it further comprises a source of impulse current electrically connected to the contact system and to the overcurrent detector critical.

 Preferably, the automatic load switch includes an auxiliary critical overcurrent detector coupled to the pulse current source.

 Also preferably, the pulse current source comprises at least one pulse current trainer electrically connected to at least one switch electrically coupled to the contact system and to the critical overcurrent detector or to an auxiliary critical situation detector.

Likewise, the pulse current source switch comprises at least one thyristor and at least one diode, the anode and the cathode of which are respectively connected to the pulse current trainer, while the thyristor control electrode is coupled to the detector. critical situation or to the auxiliary critical situation detector,
Preferably also the cathode of the thyristor is connected to the electrodynamic current limiter while the anode of the diode is connected to a contact connected to the displacement and fixing block of the contact or to the critical situation detector.

 The anode of the diode is connected to the electrodynamic current limiter, and the cathode of the thyristor to a contact connected to the displacement and fixing block of the contact or to the critical situation detector.

 The pulse current source switch advantageously comprises at least one group of four thyristors connected in bridge, the connection point of the anodes of two thyristors and the connection point of the cathodes of the two other thyristors being connected to the current pulse trainer while one of the points joining the cathode and the anode of two thyristors is connected to the electrodynamic current limiter.

 Also preferably, the connection point of the cathode and the anode of the two other thyristors is connected to the contact connected to the displacement and fixing block or to the critical situation detector, and the thyristor control electrodes are connected to the detector. critical situation or to the auxiliary critical situation detector.

 Advantageously, the pulse current formulator comprises at least one voltage source connected in parallel to at least one capacitor whose terminals are connected to the switch.

 Preferably, the pulse current formulator further comprises at least one inductive element forming with the capacitor at least one oscillating circuit.

 The present invention makes it possible to increase the electrodynamic forces at the moment when a critical situation occurs which reduces the duration of disconnection while improving the current limitation.

The present invention will be better understood from the following description relating to examples of implementation and by the appended drawings in which:
FIG. 1 represents an automatic load switch, implementing the method according to the invention, with a pulse current source with two inputs;
FIG. 2 represents the automatic load switch, implementing the method according to FIG. 1, with a pulse current source with eight inputs;
Figure 3 shows the automatic load switch, implementing the method according to Figure 1 with an auxiliary critical situation detector;
FIG. 4 represents the automatic load switch implementing the method according to FIG. 2 with an auxiliary critical situation detector;
FIG. 5 is the block diagram of a switch with the cathodes of the thyristors connected to an electrodynamic current limiter, according to the invention;
FIG. 6 represents the block diagram of the switch with the anodes of the diodes connected to the electrodynamic current limiter, according to the invention;
Figure 7 shows the block diagram of a switch with two groups of thyristors branches in bridge, according to the invention;
Figure 8 shows the block diagram of a pulse current trainer according to the invention;
Figure 9 is the block diagram of the pulse current trainer according to Figure 8 with inductive elements, according to the invention.

 - The process of automatic interruption of a charge consists in passing the charging current through the contact system to create electrodynamic forces opening the contacts of at least one pair of contacts of the contact system, and in that it sends a critical situation signal.

Simultaneously with the emission of the critical situation signal, an auxiliary current is created in the form of a pulse the magnitude and duration of which are sufficient to open the contacts when the critical situation arises, current which is passed through the contact system. Then, mechanical forces are created to move and fix one of the contacts of this pair.

 As the auxiliary current flows through the contact system, it is added to the load current.

 The automatic load switch implementing the method according to the invention for the automatic + load interruption, comprises a contact system (fig. 1) having two pairs of contacts 2, 3. The pairs of contacts 2, 3 are constituted, respectively, by contacts 4, 5 and 6, 7. Contacts 4 and 6 are mechanically linked to pressure springs 8 and 9 and, electrically, to electrodynamic current limiters 10 and 11. The current limiters 10 and 11 are fixed on a base 12. The pairs of contacts 2 and 3 are respectively connected to arc extinguishers 13 and 14 used to deflect and extinguish the arc gushing between the respective contacts 4, 5 and 6, 7.

The contacts 5 and 7 are, respectively, connected to critical situation detectors 15 and 16 and are fixed on a common cross-member 17. The contact 7 is linked to the block 18 for moving and fixing the contact. The detectors 15 and 16 are connected to a pulse current source 19, respectively, by their inputs 20 and 21. The current limiters 10 and 11 and the contacts 5 and 7 are, respectively, connected to the outputs 22, 23 and 24, 25 from source 19.

 The pulse current source 19 comprises a current pulse trainer 26 whose outputs 27 and 28 are connected to a switch 29. The inputs and outputs of switch 29 are, respectively, the inputs 20, 21 and the outputs 22, 23, 24, 25 from source 19.

 Connected to the current limiters 10 and 11 and to the detectors 15 and 16, a load 30 represents any device, sensitive to overcurrents, which can be disconnected using the automatic switch forming the subject of the invention.

 According to another alternative embodiment of the automatic load switch implementing the automatic load interruption method according to the invention, the pulse current source 19 comprises a switch 31 (fig. 2) with eight inputs which simultaneously sound the inputs 32, 33, 34, 35, 37, 38, 39 of the pulse current source 19, connected to the critical situation holders 15, 16. The outputs of the switch 31 are, respectively, the outputs 40, 41, 42, 43 of the pulse current source 19, connected, respectively, to the current limiters 10, 11 and to the contacts 5, 7.

 According to another alternative embodiment, the automatic load switch implementing the automatic load interruption method according to the invention comprises an auxiliary critical situation detector 44 (FIG. 3) connected to the inputs 20, 21 of the pulse current source 19.

The input 45 of the detector 44 is connected to the load 30. The outputs 24 and 25 of the source 19 are connected, respectively, to the critical situation detectors 15 and 16.

According to yet another variant of the automatic load switch, implementing the hemlock for automatic load interruption according to the invention, the inputs 32, 33, 34 35, 3, 37, 38, 39 of the source of impulse current 19 are connected rah-s emergency situation detector 44 auxiliary
(fig. 4).

 According to one embodiment of the pulse current source 19, the switch 29 (fig. 1, 3) comprises two thyristors 46 and 47 (fig. 5), the anodes of which are connected to a connection point 48, and two diodes 49 and 50, the cathodes of which are connected to a connection point 51. The connection points 48 and 51 are respectively connected to the inputs 27 and 28 of the pulse current trainer 26. The outputs of the anodes of the diodes 49 and 50 are, respectively, the outputs 24 and 25 of the pulse current source 19 and the outputs of the thyristor cathodes 46 and 47 serve, respectively, as outputs 22 and 23 of the source 19.

 In another variant of the pulse current generator 19, the cathodes of the thyristors 46 and 47 (fig. 6) of the switch 29 are, respectively, the outputs 24, 25 while the anodes of the diodes 49 and 50 are, respectively, the outputs 22 and 23 from source 19.

 In another variant of the pulse current source 19, its switch 31 (fig. 2, 4) comprises two groups of four thyristors 52, 53, 54, 55 and 56, 57, 58, 59 (fig. 7). The thyristors 52, 53, 54, 55 are connected according to a bridge circuit, and the thyristors 56, 57, 58, 59 according to another such circuit. The point 60 of connection of the anodes of the thyristors 52, 54, 56, 58 and the point 61 of connection of the cathodes of the thyristors 53, 55, 57, 59 are connected, respectively, to the outputs 27, 28 of the pulse current trainer 26.

The cathode and anode of the thyristors 52 and 53 are connected to a common point 62, those of the thyristors 54 and 55, to a connection point 63, those of the thyristors 56 and 57, to a point 64, those of the thyristors 58 and 59, at a connection point 65. The control electrodes 52, 53, 64, 55, 56, 37, 38, 39 respectively constitute the inputs 32, 33, 34, 35, 36, 57, 58, 59 of the pulse current source 19 while the points 62, 63, 64, 65 are respectively, the outputs 40, 41, 42, 43, of the pulse current generator 19.

 According to a variant, the pulse current trainer 26 (fig. 1, 2, 3, 4) comprises a voltage source 66 (fig. 8) having a capacitor 67 connected in parallel.

 According to another variant, the pulse current formulator 26 (fig. 1, 2, 3, 4) comprises two voltage sources 68 and 69 (fig. 9) with capacitors, respectively, 70 and 71, connected in parallel on the corresponding source.

One of the terminals of the capacitor 70 is connected to one of the terminals of the capacitor 71. Between the other terminals of the capacitors 70 and 71, an inductive element 72 is connected. At the point 73 of connection of the terminals of the capacitor 70 and of the element inductive 72 is connected an inductive element 74.

The capacitor 70 and the inductive element 74 form a first oscillating circuit, the capacitor 71 and the inductive elements 72 and 74 forming a second oscillating circuit.

 The automatic load switch implementing the automatic load interruption method according to the invention operates in the following manner.

 On a signal from the critical situation detectors 15, 16 (fig. 1, 2) the switch 29 or the switch 31 of the pulse current source 19 becomes conductive and passes the auxiliary current pulse from its pulse current trainer 26 by the contact system 1, or by the electrodynamic current limiters 10, 11 and the contacts 4, 5 and 6, 7.

The auxiliary current creates electrodynamic forces rejecting the contacts 4, 6. Between the open contacts 4, 5 and 6, 7 arcs which are deflected on the arc extinguishers 13, 14. In the circuits of the load 30 , to which the pairs of contacts 2, 3 of the automatic load switch are connected, is added the voltage of the arcs formed between the contacts 4, 5 and 6, 7, causing a limitation of the load current and breaking of these circuits. After the auxiliary current has ceased, the electrodynamic forces, acting on the contacts 4 and 6, decrease and the contacts 4 and 6, under the action of the contact pressure springs 8 and 9, begin to move in the opposite direction, tending to close on contacts 5 and 7.

 The size and duration of the auxiliary current pulse must be such that before the return of the contacts 4 and 6 rejected in the initial position, the block 18 for the displacement and fixing of the contact is triggered and that the displacement of the contacts 5 and 7 begins.

 To accelerate the triggering of block 18, switch 29 or 31 is released. on a signal from the auxiliary critical sensor 44 (fig. 3, 4) and the additional current pulse passes through the contact system .1 (as described above) and through the critical sensors 15 , 16.

 The operation of the pulse current source 19 for direct current on the load 30 is described below.

 The signals from the critical situation detectors 15, 16 (fig. 1) arrive at the thyristor control electrodes 46, 47 (fig. 5) of the switch 29.

By unlocking, the thyristors 46, 47 allow the discharge current of the capacitor 67, previously charged by the voltage source 66 (fig. 8) of the pulse current formulator 26 to pass. The discharge current of the capacitor 67, passing through the thyristors 46, 47 (fig. 5) of the switch 29 (fig. 1, 5), by the current limiters 10, 11 and by the contacts 4, 5 and 6, 7 of the contact system 1, by the diodes 49, 50 of the switch 29, according to the invention constitutes an auxiliary current pulse.

 We now examine the case where the auxiliary current does not correspond to the direction of the current in the load 30. Then, the discharge current of the capacitor 67 passing through the thyristors 46, 47 (fig. 6) of the switch 29 (fig. 1, 6), by the contacts 4, 5 and 6, 7 and by the current limiters 10, 11 of the contact system 1, by the diodes 49, 50 of the switch 29, constitutes according to the invention, an auxiliary current pulse.

 On receiving the alarm signal from the detector 44 (FIG. 3), the discharge current from the capacitor 67 also passes through the critical situation detectors 15, 16.

 To ensure a sufficient duration of the auxiliary current pulse and the desired shape of this pulse, the auxiliary current, in the formatter 26 (fig. 9), is formed by the currents created in two oscillating circuits at frequencies different from the natural oscillations. , one of these comprising the inductive element 74 and the capacitor 70 previously charged with the source 68, the other, the inductive elements 72 and 74 and the capacitor 71, previously charged, with the source 69.

 The operation of the pulse current source 19 for an alternating load current in the load 30 is examined.

 The alarm detectors 15, 16 (fig. 2) react to the direction of the current in the load 30. For a direction of the current in the load 30, the signals of the detectors 15 and 16 unblock the thyristors 52, 55 and 56, 59 (fig. 7) of switch 31 (fig. 1, 2, 7). The auxiliary current pulse passes from the formatter 26 through the thyristors 52, 56, through the current limiters 10, 11 and through the contacts 4, 5 and 6, 7 of the contact system 1, through the thyristors 55, 59. For the other direction of the current in the load 30, the thyristors 53, 54 and 57, 59 are released and the auxiliary current pulse passes from the formatter 26 by the thyristors 54, 58, by the contacts 4, 5 and 6, 7 , by the current limiters 10, 11 of the contact system, by the thyristors 53, 57. In a similar manner to the case described above, on reception of the alarm signal from the auxiliary detector 44 (FIG. 4), the auxiliary current also passes through the detectors 15, 16.

 The present invention makes it possible to use the known automatic load switches without modification of complex constructions, which allows the implementation of the automatic load interruption method according to the invention.

 Of course, the present invention is in no way limited to the embodiments described and shown; it is susceptible of numerous variants accessible to those skilled in the art, su-vant the envisaged applications and without departing from the spirit of the invention.

Claims (12)

 1.- Method of automatic interruption of the charge consisting in passing the charging current through a contact system to create electrodynamic forces opening the contacts of at least one pair of contacts of the contact system, to send a signal critical situation and to create mechanical forces to move and fix one of the contacts of this pair of contacts, the said method being activated because on an emergency signal, an auxiliary current is created in the form of '' an impulse whose value and duration are sufficient to open the contacts at the moment when a critical situation appears, current that is passed through the contact system.  2.- Method according to claim 1, c a r a c t é r i s in that the auxiliary current, at the time of its passage through the contact system, is added to the charging current.  3. An automatic load switch for implementing the method according to claim 1, comprising a contact system (') with at least one pair of contacts (2, 3) and with at least one electro-dynamic limiter. current (10, 11) electrically coupled together, at least one critical situation detector (15, 16) electrically connected to the pair of contacts of the contact system, a block (18) for moving and fixing the contact mechanically attached to the pair of contacts of the contact system and of the critical situation detector and at least one arc extinguisher (13, 14) for deflecting and extinguishing the electric arc arising between the contacts, characterized in that it further comprises a source (19) of pulsed current electrically connected to the contact system and to the critical situation detector.  4.- Autemat.que switch according to claim 3, c a r a c t e rized in that it cor - takes an auxiliary critical situation detector (44) connected to the current source (19) iSilpu sionne7.  5.- auto.erioue switch according to claim 3 or 4, charac terized in that the impulse current source (19j comprises at least one impulse current trainer (26) connected to at least one switch (29) electrically coupled to the contact system and to the critical situation detector or to an auxiliary critical situation detector.  6. An automatic switch according to claim 5, characterized in that the switch (29) of a source f19) of impulse current comprises at least one thyristor l4t 47) and at least one diode (49, 50) whose anode and cathode are respectively connected to the impulse current trainer, while the thyristor control electrode is connected to the critical situation detector or to the auxiliary critical situation detector.  7. An automatic switch according to claim 6, characterized in that the thyristor cathode is connected to the electrodynamic current limiter, and the anode in contact connects to the displacement and contact fixing block, or to the detector of critical situation.  8. An automatic switch according to claim 6, characterized in that the anode of the diode is connected to the electrodynamic current limiter, and the thyristor cathode to the contact connected to the displacement and contact fixing block or to the critical situation detector.  9. An automatic switch according to claim 5, characterized in that the switch of the pulse current source comprises at least one group of four thyristors connected in point, the connection point of the anodes of two thyristors and the point of connection of the cathodes of the two other thyristors being connected to the pulse current trainer while one of the connection points of the cathode and the anode of two thyristors is connected to the electrodynamic current limiter.  10. An automatic switch according to claim 9, characterized in that the connection point of the cathode and the anode of the two other thyristors is connected to the contact connected to the displacement and fixing block or to the situation detector. critical, and thyristor control electrodes, to the critical situation detector or to the auxiliary critical situation detector.  11. An automatic switch according to claim 5, it is in that the pulse current pulse trainer comprises at least one voltage source connected in parallel to at least one capacitor whose terminals are connected to the switch.  12. An automatic switch according to claim 11, it is in that the pulse current trainer further comprises at least one inductive element forming with the capacitor at least one oscillating circuit.