EP0105786B1 - Branch circuit breaker with an electronic trip device and remotely controlled calibration - Google Patents

Description

• un mécanisme d'actionnement manuel et de déclenchement automatique sur défaut piloté par un relais de déclenchement,
• un capteur d'intensité pour détecter le courant circulant dans chaque conducteur de phase du réseau,
• un bloc électronique de traitement du signal émis par le capteur pour délivrer un ordre de déclenchement au relais quand ledit courant dépasse une fonction prédéterminée,
• et des moyens d'ajustage dudit signal comprenant un pont résistif diviseur de tension agencé entre le capteur et le bloc électronique.

The invention relates to a multiple-gauge branch circuit breaker inserted downstream of an energy meter in an alternative distribution network for supplying the subscriber's low-voltage electrical installation, the change in rating of the circuit breaker being controlled remotely by the agent using a remote control circuit housed in the meter box, the circuit breaker comprising:

• a manual actuation and automatic tripping mechanism on fault controlled by a tripping relay,
• an intensity sensor to detect the current flowing in each phase conductor of the network,
• an electronic block for processing the signal emitted by the sensor to issue a tripping order to the relay when said current exceeds a predetermined function,
• and means for adjusting said signal comprising a resistive voltage divider bridge arranged between the sensor and the electronic unit.

The document EP-A1-0079270 (Article 54 (3) (4) of the EPC) relates to a circuit breaker of the kind mentioned. The gauge switch is nevertheless attached to or integrated into the circuit breaker, and mechanically coupled to the cursor of a resistive bridge or a potentiometer connected in parallel to the terminals of the rectifier. The switch is formed by a step-by-step actuator with electromechanical control remotely controlled from the meter box by an auxiliary generator associated with a caliber preselector. The arrangement of such a device is complicated and expensive.

It has been envisaged to leave the connection circuit breaker box shown in FIG. 3 of document EP-A1-0061364, the resistive voltage divider bridge and the manual switch, to place them near the meter, but a fault in the circuit of connection, by breaking of one or more wires, or by short-circuit between two wires can hinder the good functioning of the circuit breaker, either by absence of power supply of the electronic signal processing module causing the paralysis of the circuit breaker, or by an adjustment uncontrolled caliber likely to cause untimely triggering. The link circuit between the telecalibration circuit and the circuit breaker necessarily requires three pilot wires.

In document EP-A1-0079271 (Article 54 (3) (4) of the EPC) the telecalibration problem is solved by keeping all the organs of the circuit breaker tripping module and by providing a second monitoring module near the meter of the power subscribed by the subscriber. This powerful device with two electronic modules is nevertheless complicated and expensive.

The present invention aims to remedy the aforementioned drawbacks and to allow the production of a simple and reliable telecalibration device allowing the continuity of the operation of the circuit breaker regardless of the state of the link circuit.

This object is achieved by the characteristics of claim 1. The current sensor being associated with a rectifier supplying the resistive bridge, the series resistance is connected between one of the terminals of the rectifier and a connection point with a connecting conductor, and that the shunt resistor includes a resistor connected to the opposite polarity terminal of the rectifier and to the other connecting conductor.

The caliber switch of the remote control circuit cooperates with a plurality of selection pads allowing the series connection with the resistance of a variable resistance loop between zero and infinity depending on the position of the switch, the maximum caliber corresponding to the position of the switch for short-circuiting the connecting conductors, the lower rating intervening on the pad corresponding to an infinite resistance of the loop and the absence of shunt resistance, while the intermediate rating operates on the pad by insertion of a predetermined resistance.

• circuit de liaison à deux fils,
• en cas de court-circuit volontaire du circuit de liaison, le disjoncteur n'est pas paralysé et reste en service sur le calibre maximum,
• en cas de coupure accidentelle ou volontaire du circuit de liaison, ou d'une défectuosité du commutateur de calibre, le disjoncteur fonctionne toujours sur le calibre minimum,
• en mesurant la résistance de la boucle du circuit de liaison, on peut détecter toute fraude. A cet effet, le commutateur de calibre peut être positionné sur un plot de télédéclenchement pour la mise en service d'un circuit de condamnation susceptible d'interrompre à distance la fourniture d'électricité, sans possibilité de referme- ture du disjoncteur par l'abonné.

The advantages of this device are as follows:

• two-wire link circuit,
• in the event of a voluntary short-circuit in the link circuit, the circuit breaker is not paralyzed and remains in service on the maximum rating,
• in the event of accidental or deliberate interruption of the link circuit, or a fault in the rating switch, the circuit breaker always operates on the minimum rating,
• by measuring the resistance of the loop of the link circuit, one can detect any fraud. For this purpose, the gauge switch can be positioned on a remote-triggering pad for the commissioning of a locking circuit capable of interrupting the supply of electricity remotely, without the possibility of closing the circuit breaker by the subscriber.

• la figure 1 représente le schéma électrique d'un disjoncteur de branchement à déclencheur électronique associé à un dispositif de télécalibrage selon l'invention ;
• la figure 2 illustre le schéma du dispositif de télécalibrage ;
• les figures 3 à 5 montrent les schémas électriques équivalents du pont résistif pour différentes positions A, B, C du commutateur de calibre CM, ;
• la figure 6 est une variante de réalisation du pont résistif selon la figure 1.

Other advantages and characteristics of the invention will emerge more clearly from the description which follows of various embodiments given by way of nonlimiting examples and represented in the appended drawings in which:

• FIG. 1 represents the electrical diagram of a circuit breaker with electronic trip associated with a telecalibration device according to the invention;
• FIG. 2 illustrates the diagram of the telecalibration device;
• Figures 3 to 5 show the equivalent electrical diagrams of the resistive bridge for different positions A, B, C of the caliber switch CM,;
• FIG. 6 is an alternative embodiment of the resistive bridge according to FIG. 1.

In Figure 1 is shown an electrical connected four-pole circuit breaker downstream of an energy meter 11 in an alternative distribution network for the supply of the low-voltage electrical installation of a customer having subscribed to a distribution company. The counter 11 is housed in an external electrical cabinet accessible to the distributor, while the circuit breaker is arranged in the subscriber's room, separated from the cabinet by a certain distance. The circuit breaker can be of the bipolar type in the case of a single-phase distribution with neutral.

The connection circuit breaker is of multiple ratings and includes a mechanism for operating 12 of the movable contacts 16, the latter being inserted into the active conductors of phase R, S, T and neutral N of the network. The mechanism 12 is actuated either manually by a trigger button 18 and a reset button 20, or automatically by means of a trigger bar associated with an electromagnetic relay 22, in particular of the polarized type. The coil 24 for controlling the trip relay 22 is controlled by an electronic control module 26 capable of monitoring the intensity of the current in the active conductors of the network and of producing an order to open the relay 22 if the selected rating corresponding to the power subscribed by the subscriber.

The electronic module 26 for controlling the circuit breaker has its own current of the type described in document EP-A1-0061364 to which reference will be made for further details; it comprises in particular a current sensor 28 associated with each of the phases of the network to detect the current in each phase conductor, and an electronic processing unit 30 for the signal emitted by the sensor to deliver to the coil 24 a trigger signal when the current exceeds a predetermined current function. Each sensor 28 is formed by an intensity transformer whose secondary winding is connected to a diode rectifier bridge D ₁₁ to D _14; D ₁₅ to D ₁₈ ; D ₁₉ to D ₂₂ . The outputs of the bridges are connected in parallel and connected to the terminals of a Zener diode D ₁₀ and a storage capacitor C ₄ . Between the capacitor C ₄ and the electronic processing unit 30 is arranged a resistive bridge 32 voltage divider for adjusting the rating, the voltage taken at the output of the resistive bridge 32 being proportional to the intensity of the current passing through the sensors 28 after adjustment by bridge 32. The output of bridge 32 is connected to a capacitor C ₁ shunted by a Zener diode D ₁ , which protects the processing circuit 30.

The circuit 30 comprises a first operational amplifier AO ₁ controlled by a bias circuit with resistance R ₃ and diode D ₃ , associated with the negative input, and by a delay circuit with resistance R, and capacitor C ₂ connected to the positive entry. A discharge circuit with resistance R ₂ and diode D ₂ is connected in parallel to the terminals of the capacitor C ₂ to provide temperature compensation. The output of the amplifier AO is connected by a diode D ₆ to the trigger of a thyristor Th, connected in series with the coil 24 of the trigger relay 22. Upon the appearance of an overload detected by one of the sensors 28, the capacitor C ₂ is charged through the resistor R ₁ , and as soon as the voltage across the terminals of the capacitor C ₂ exceeds the value of the voltage applied to the negative input, the amplifier AO ₁ is released to start the thyristor Th ₁ , which becomes conductive by causing the tripping of the circuit breaker. The first operational amplifier AO forms a long delay tripping circuit, the time delay being provided by the progressive charge of the capacitor C ₂ through the resistor R ₁ .

A second operational amplifier A0 ₂ is polarized in an analogous manner by a polarization circuit connected to the negative input and comprising a diode D ₄ in series with a resistor R ₄ . The positive input of amplifier A0 ₂ is connected to capacitor C ₁ through a resistor R ₁₃ and a Zener diode D ₈ . The output of amplifier A0 ₂ is connected to the trigger of thyristor Th, via a diode D ₅ . When the voltage across the capacitor C ₁ is high and exceeds the conduction threshold of the diode D ₈ , the latter becomes conductive and unlocks the amplifier A0 ₂ which delivers a trigger signal to the thyristor Th, causing the excitation of the relay 22. This second amplifier A0 ₂ constitutes a short-delay tripping circuit intervening in the event of an overload of a value greater than that causing the long-delay tripping of the first amplifier AO ₁ .

According to the invention, the adjustment of the caliber is controlled remotely by means of a remote control circuit 34, placed inside the meter cabinet 11. The circuit 34 includes a connection terminal 36 electrically connected to an auxiliary socket 38 of the circuit breaker by two connecting conductors 40, 42. One of the pads of the auxiliary socket 38 is connected to the positive pole of the rectifier bridges D ₁₁ to D ₂₂ by means of a series resistor Rg, while the other pad is connected to the negative pole by a resistor R _{12 '} A diode D ₂₃ is inserted between the connection point 44 of the resistor Rg and the cathode of the Zener diode D ₁ to prevent the discharge of the capacitor C ₁ in the resistive bridge 32 The remote control circuit 34 (FIG. 2) contains a caliber switch CM ₁ , the adjustment cursor of which cooperates with a plurality of selection pads A, B, C, D, ... each corresponding to a predetermined operation of the circuit breaker. . A terminal 36 of the circuit 34 is associated with a loop 46 of variable resistance depending on the position of the switch CM ₁ on the pads A, B and C. This loop 46 is connected in series by the connection conductors 40, 42 with the resistor R ₁₂ to constitute the shunt resistor arranged between point 44 and the negative pole. The loop 46 of the circuit 34 comprises a first conductor 40a connected to the cursor of the switch CM ₁ , and a second conductor 42a connected to the pads A, B, C, D respectively by a short-circuit link 48, by a resistor R ₁₁ , by an open circuit, and by an injection circuit 50 of a remote tripping voltage. The injection circuit 50 is equipped with a power supply 52 and an auxiliary switch CM ₂ , the commissioning of which ensures the remote tripping of the circuit breaker. The resistance of the loop 46 can be controlled by means of a measuring device 54 connected to the circuit 34 in a fixed or temporary manner. It is noted that the resistive bridge 32 voltage divider is formed by the resistors Rg and R ₁₂ of the electronic module 26, and by the loop 46 of the remote control circuit 34.

• Lorsque le curseur du commutateur de calibre CM, se trouve sur le plot A, la boucle 46 présente une résistance nulle, et la résistance shunt du pont résistif 32 se limite à la résistance R₁₂ correspondant au calibre le plus élevé, par exemple 90 A (fig. 3). Le pont résistif 32 diviseur de tension est ainsi formé par la résistance série Rg et par la résistance shunt R₁₂, et coopère avec les condensateurs C₄ et C₁ pour constituer une cellule de filtrage en Il. La diode D₂₃ empêche la décharge du condensateur Ci dans la résistance R₁₂. 11 en résulte que la composante alternative résultante à la sortie de la cellule est invariable quel que soit la nature du courant de surcharge, en cas de défaut monophasé ou triphasé.

The operation of the own current and telecalibration circuit breaker according to the invention is as follows:

• When the cursor of the caliber switch CM is located on the pad A, the loop 46 has zero resistance, and the shunt resistance of the resistive bridge 32 is limited to the resistor R ₁₂ corresponding to the highest rating, for example 90 A (fig. 3). The resistive bridge 32 voltage divider is thus formed by the series resistor Rg and by the shunt resistor R ₁₂ , and cooperates with the capacitors C ₄ and C ₁ to form a filter cell in Il. The diode D ₂₃ prevents the capacitor Ci from discharging into the resistor R ₁₂ . It follows that the resulting AC component at the output of the cell is invariable regardless of the nature of the overload current, in the event of a single-phase or three-phase fault.

The actuation of the switch CM ₁ on the pad B causes the insertion of the resistor R ₁₁ . The shunt resistor of bridge 32 is made up of the sum of resistors R ₁₁ and R ₁₂ (fig. 4) and corresponds to an intermediate rating, for example 75 A.

In position C of the switch CM ₁ (fig. 5), the loop 46 has infinite resistance. The absence of a shunt resistor nevertheless allows the module 26 to operate on the minimum rating (for example 60 A), determined by the series resistor Rg.

It is noted that the change in rating by the switch CM ₁ is remotely controlled by the agent from the circuit 34 by virtue of the two connecting conductors 40, 42. In the event of a voluntary short circuit of the two conductors 40, 42, the electronic module 26 circuit breaker control unit always remains in service on the maximum rating. An accidental or deliberate cut of one or both conductors 40, 42, or a bad contact of the switch CM, does not hamper the operation of the module 26 which is then set to the minimum rating. Thanks to the measuring device 54, the resistance of the loop 46 is monitored to control the size of the circuit breaker and to detect any fraud. When the power subscribed by the subscriber does not correspond to the rating displayed by the switch CM _t , it is possible to remotely condemn the subscriber's connection by positioning the rating switch CM ₁ on the pad D, and by closing the auxiliary switch CM ₂ of the circuit 50. The loop 46 applies a permanent voltage to the input of the electronic unit 30 immediately involving the short-delay tripping circuit of the operational amplifier AO ₂ . This results in the opening of the contacts 16 of the circuit breaker and the interruption of the supply of electricity to the subscriber. The connection is locked as long as the CM caliber switch remains on pin D and the auxiliary switch CM ₂ remains closed.

According to the variant of FIG. 6, the shunt resistor R ₁₂ is replaced by a plurality of elementary resistors R ₂₀ , R ₂₁ , R ₂₂ ... R _x in parallel, the insertion of which by one or more associated switches corresponds to the different ratings of the circuit breaker.

According to another variant (not shown), the value of the shunt resistor R ₁₂ is adjustable allowing local calibration of the circuit breaker, independently of the remote calibration by the circuit 34.

Claims (7)

1. Multi-size branch circuit breaker, inserted downstreams of an energy counter (11) in an alternating distribution network for the supply of an electrical low-voltage installation of a consumer, the size changing of the circuit breaker being remotely controlled by the technical agent by means of a remote control circuit (34) arranged in the housing of the counter, said circuit breaker comprising :

a mechanism for manual operating (18, 20) and for automatic tripping when a fault occurs, controlled by a trip relay (22),

an intensity sensor (28) to detect the current flowing in each phase conductor (R, S, T) of the network,

an electronic assembly for processing the signal emitted by the sensor (28) in order to deliver a tripping order to the relay (22) when said current exeeds a predetermined function,

and adjusting means of said signal, comprising a voltage divider resistive bridge (32) arranged between the sensor (28) and the electronic assembly ;

the resistive bridge (32) of the circuit breaker being constituted by a series resistance (R9) and a shunt resistance, and the remote control circuit (34) comprising a size switch (CM1) connected electrically with the resistive bridge (32) by a link circuit (40, 42) able to generate the variation of the shunt resistance by operating the size switch (CM1).

2. Branch circuit breaker according to claim 1, in which each current sensor (28) is associated with a rectifier (D11-D22) supplying the resistive bridge (32), the series resistance (R9) being connected between one of the terminals of the rectifier (D11-D22) and a link point (44) with a link conductor (40), and the shunt resistance comprising a resistance (R12) connected with the rectifier terminal of opposite polarity and with the other link conductor (42).

3. Branch circuit breaker according to claim 2, in which the size switch (CM1) of the remote control circuit (34) cooperates with several selection contacts (A, B, C...) authorizing the series connection with a resistance (R12) of a loop (46) of a resistance variable between zero and infinite, according to the position of the switch (CM1), the maximum size corresponding to the position (contact A) of the switch (CM1) for the short- circuiting of the link conductors (40, 42), the lower size acting on the contact (C) corresponding to an infinite resistance of the loop and to the absence of the shunt resistance, while the middle size acts on contact (B) by inserting a resistance (R11

4. Branch circuit breaker according to claim 3, in which the remote control circuit (34) can be provided with a monitoring apparatus (54) of the resistance of the loop (46).

5. Branch circuit breaker according to claim 2, 3 or 4, in which the remote control circuit (34) comprises a remote controlled interrupting circuit (50) which starts working when the size switch (CM1) is positioned on a remote controlled tripping contact (D) different from the selection contacts (A, B, C).

6. Branch circuit breaker according to claim 5, in which the interrupting circuit (50) comprises a supply (52) and an auxiliary switch (CM2) for the input of a tripping voltage into the shunt resistance circuit, the voltage being maintained when the size switch (CM1) remains on the contact (D) and in the closing position of the auxiliary switch (CM2).

7. Branch circuit breaker according to claim 2, 3, 4, 5 or 6, comprising a first filter capacitor (C4) parallel connected with the terminals of the rectifier and a second storage capacitor (C1) connected with the input of the electronic assembly, a diode (D23) being inserted between the link point (44) of the series resistance (R9) and the input of the electronic assembly in order to avoid the discharge of the second capacitor (C1) in the shunt resistance.

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