Differential electrical protection device, associated electrical installation and control method

Abstract

Differential electrical protection device, associated electrical installation and control method The present invention relates to a differential electrical protection device (10) comprising a power supply circuit (16), configured to be powered with a power supply voltage (Ue), a coil (21), configured to switch contacts (23, 24) into an opening configuration, a control element (26), configured to switch between a conducting state and a blocked state, and an electronic control unit (18) comprising a power supply regulation module (42), configured to measure an internal current representative of the power supply voltage (Ue), and an information processing unit (90) configured to determine a phase of the power supply voltage (Ue), the information processing unit (90) comprising a control module,configured to control the control element (26) in the on state when a detection module detects a differential fault and the phase of the supply voltage (Ue) is equal to a tripping phase. Figure for the abstract: Figure 1,

Description

Title of the invention: Differential electrical protection device, associated electrical installation and control method

[0001] The present invention relates to a differential electrical protection device, an electrical installation and an associated control method.

[0002] To interrupt the flow of a current in a circuit comprising a source and a load following a differential fault, it is known to use a differential electrical protection device. In a known manner, these devices generally comprise a coil. In the event of a differential fault, the coil switches to an active state in which it is traversed by a current, and generates a force sufficient to move contacts, and open the circuit. In known devices, the current flowing through the coil is not measured and its characteristics are therefore unknown. To ensure the opening of the contacts, without information on the characteristics of the current flowing through the coil, the active state of the coil is generally maintained for more than 30 ms, for example between 35 and 60 ms, to ensure that a current sufficient to move the contacts flows through the coil.However, this causes premature wear of the coil, which limits the lifespan of the latter and, more generally, of the differential electrical protection device.

[0003] The aim of the invention is then to propose a device making it possible to limit the wear of the coil.

[0004] To this end, the invention relates to a differential electrical protection device, configured to be connected between a source and a load, the device comprising: - a power supply circuit, configured to be connected to the source, and to be electrically powered by the source under an alternating supply voltage, variable over time; - contacts, configured to switch into an opening configuration, in which the source and the load are isolated from each other, and into a closing configuration, in which the source and the load are connected to each other; - a differential detector, configured to measure a differential intensity of a differential current flowing in the load and emit a fault signal representative of the differential intensity; - a coil, configured to switch between a resting state and an active state, in which the coil switches the contacts into the opening configuration from the closing configuration; and - a control element, configured to switch between an on state, in which the control element allows power to be supplied to the coil which then switches to the active state, and a blocked state, in which the control element prevents power to the coil which then switches to the rest state; and - an electronic control unit comprising: • a power supply regulation module, connected to the power supply circuit, comprising a current detector, configured to measure an internal intensity of an internal current flowing in the power supply regulation module, the internal intensity being representative of the power supply voltage; and • an information processing unit configured to determine a phase of the supply voltage from the internal intensity measured by the current detector, the information processing unit comprising a detection module, configured to detect a differential fault from the fault signal emitted by the differential detector and a control module, configured to control the control element in the on state when the detection module detects a differential fault and the phase of the supply voltage, determined by the information processing unit from the internal intensity, is equal to a trigger phase.

[0005] Thanks to the invention, when a differential fault is detected, the control element is controlled in the on state only when the phase of the supply voltage is equal to the triggering phase. The phase of the supply voltage is directly connected to a current flowing through the coil when it is in the active state. Thus, knowledge of the phase of the supply voltage makes it possible to determine the current flowing in the coil, in particular a phase of the current flowing in the coil. The switching of the coil into the active state is synchronized with the phase of the supply voltage, and makes it possible to limit the current flowing in the coil to the strict minimum, by choosing the triggering phase. Thus, premature wear of the coil is limited.

[0006] According to other advantageous aspects of the invention, the device comprises one or more of the following characteristics, taken individually or in all technically possible combinations:

[0007] - The information processing unit determines that the phase of the voltage supply voltage is equal to the trigger phase, by detecting an extremum of the internal current, and waiting for a synchronization duration, measured from the moment when the extremum of the internal intensity is detected, has elapsed.

[0008] - The information processing unit is further configured to determine a effective value of the supply voltage from the internal current, and wherein when the effective value of the supply voltage is less than or equal to an effective value threshold, the trigger phase is equal to Nir with N equal to 0, 1 or 2, and when the effective value of the supply voltage is greater than the effective value threshold, the trigger phase is equal to Kir / 2, with K equal to 1 or 3.

[0009] - The information processing unit is further configured to calculate a control duration of the control element in the on state by the control module as a function of the effective value of the supply voltage.

[0010] - The contacts are connected between the power supply circuit and the load; - the detection module is further configured to compare the fault signal to a fault threshold, a differential fault being detected when the fault signal is greater than the fault threshold, and is further configured to compare the fault signal to an end-of-fault threshold; and - the control module is further configured to control the control element in the blocked state when the fault signal is less than or equal to the end of fault threshold, the control module having controlled the control element in the passing state.

[0011] - The control module is configured to control the control element in the on state by emitting a control signal in the form of at least one pulse.

[0012] - The control signal is in the form of a plurality of pulses, each edge pulse amount being separated from the rising edge of the next pulse by a duration equal to half a period of the supply voltage.

[0013] - The control signal is in the form of two pulses, the rising edge of the two pulses being separated by a duration equal to half a period of the supply voltage.

[0014] The invention also relates to an electrical installation comprising a source, a load and a differential electrical protection device as described previously.

[0015] The invention also relates to a method for controlling a differential electrical protection device as described above, the method comprising at least the following steps: - measurement of the differential current flowing in the load by the differential detector and emission of the fault signal; - measurement of internal intensity by the current detector; - detection by the detection module of a differential fault from the signal

[0016]

[0017]

[0018]

[0019]

[0020]

[0021] fault emitted by the differential detector; - determination of the phase of the supply voltage from the internal intensity measured by the current detector, by the information processing unit; and control of the control element in the on state by the control module, the detection module having detected a differential fault and the phase of the supply voltage, determined by the electronic control unit from the internal current, being equal to the trigger phase. Advantageously, the trigger phase is chosen from the following group: Nir, N being equal to 0, 1 or 2; and, Kir / 2, K being equal to 1 or 3. The invention will appear more clearly on reading the description which follows, given solely by way of non-limiting example, and made with reference to the drawings in which: - [Fig.l] [Fig.l] is a diagram of an electrical circuit comprising a differential electrical protection device according to the invention; - [Fig.2] [Fig.2] is a schematic diagram of a regulation module of a electronic control unit according to the invention; - [Fig.3] [Fig.3] is a voltage and current graph in the device according to the invention when a supply voltage is equal to a first value; - [Fig.4] [Fig.4] is a graph showing the general evolution of tension and of intensities in the device when a differential fault is present in an installation comprising the device when the supply voltage is equal to the first value; - [Fig.5] [Fig.5] is a graph of voltage and currents in the device according to the invention when the supply voltage is equal to a second value; and - [Fig.6] [Fig.6] is a flowchart of a control method implemented by the device according to the invention. [Fig.l] is a diagram of an electrical circuit 1 comprising a source 3 and a load 5, connected together by a phase conductor 7 and a neutral conductor 8. The source 3 supplies electricity and is, for example, an electric generator or a national electricity grid. The load 5 is generally a device consuming electricity, such as a domestic electrical appliance or industrial equipment. A differential electrical protection device 10, also called protection device 10, is connected between the source 3 and the load 5. The protection device 10 comprises an opening mechanism 12, a detector differential 14, a power supply circuit 16 and an electronic control unit 18, connected to the opening mechanism 12, to the differential detector 14 and to the power supply circuit 16.

[0022] The opening mechanism 12 comprises a coil 21, contacts 23 and 24 and a control element 26. The contacts 23 and 24 are respectively a phase contact 23 and a neutral contact 24.

[0023] The contacts 23 and 24 are configured to switch into an opening configuration, thereby isolating the source 3 and the load 5 from each other. The protection device 10 is then said to be triggered. The contacts 23 and 24 are also configured to switch into a closing configuration, the source 3 and the load 5 being thus electrically connected to each other. The protection device 10 is then said to be armed, in other words, is closed.

[0024] The coil 21 is configured to switch between a resting state and an active state. In the active state, the coil 21 switches the contacts 23 and 24 into the opening configuration from the closing configuration. In other words, the coil 21 acts as a trigger to switch the contacts 23 and 24 from the closing configuration to the opening configuration.

[0025] The control element 26 is advantageously a switching-controllable semiconductor component, for example a thyristor, as shown in FIGS. 1 and 2. The supply voltage is applied to the terminals of the control element 26. The control element 26 is configured to switch between an on state and a blocked state. In the on state, the control element 26 enables the coil 21 to be powered. The coil 21 then switches to the active state. In the blocked state, the control element 26 blocks the power supply to the coil 21. The coil 21 then switches to the rest state. The details of the control and the opening will be described in more detail later.

[0026] The differential detector 14 is configured to measure a differential current having a differential intensity Icd between the phase conductor 7 and the neutral conductor 8. The differential detector 14 comprises a transducer 30, which is a toroid, in the example of [Fig.l]. When a differential fault is present in the load 5, or possibly in connectors between the protection device 10 and the load 5, the differential intensity Icd is non-zero, generating an induced current in the toroid 30. The differential detector 14 also comprises a conditioning unit 32. The conditioning unit 32 is connected to the toroid 30, and notably comprises filters, in order to stabilize the induced current in the toroid 30 and improve a quality of the differential current measurement between the phase conductor 7 and the neutral conductor 8.The conditioning unit 32 is configured to output a fault signal Sd, which is representative of the differential current Icd. For example, the fault signal Sd . is an integral with respect to time of the differential intensity Icd. In the example of [Fig.4], the fault signal Sd is expressed in arbitrary units, or AU.

[0027] The power supply circuit 16 is connected to the source 3. In the example of [Fig.l], the power supply circuit 16 is connected to the source 3 via the phase 7 and neutral 8 conductors upstream of the contacts 23 and 24. In other words, the power supply circuit 16 is connected between the source 3 and the contacts 23 and 24. The source 3 electrically supplies the power supply circuit 16 with an electric current, called the power supply current, whether the contacts 23, 24 are in the open or closed configuration. According to a variant not shown, the power supply circuit 16 is connected to the phase 7 and neutral 8 conductors downstream of the contacts 23 and 24. In this case, the power supply circuit 16 is only supplied by the power supply current when the contacts 23, 24 are in the closed configuration.

[0028] In the example of [Fig.l], a supply voltage Ue is permanently applied to the supply circuit 16, in particular to the terminals of a varistor 34 included in the supply circuit 16. The supply voltage Ue is equal to a voltage delivered by the source 3. The supply voltage Ue is an alternating phase voltage between 0 and 2ir, and has an effective value Uef also called effective voltage, for example equal to 230V.

[0029] The effective voltage Uef can vary over time in an unpredictable manner, for example due to slight fluctuations on an electrical network supplying the source 3, or following a malfunction of the source 3 or of the electrical network supplying the source 3. Thus, the supply voltage Ue is variable over time due to its alternating nature and also because its effective value Uef is potentially variable over time.

[0030] The power supply circuit 16 further comprises, in the embodiment described, a power supply capacitor 36, a filter capacitor 38, a resistor 39 and a diode bridge 40.

[0031] The power supply circuit 16 converts the power supply current into a rectified input current via the diode bridge 40, and phase-shifted by a quarter of a period, in other words by ir / 2 relative to the power supply voltage Ue due to the presence of the power supply capacitor 36. The input current has a voltage called the input voltage Vin, with an effective value lower than the effective value Uef of the power supply voltage Ue. The input voltage Vin is applied to the input of the electronic control unit 18. The power supply circuit 16 thus ensures a suitable electrical supply of the electronic control unit 18, i.e. with a rectified current and voltage Vin lower than the current and voltage delivered by the source 3, to avoid damaging the electronic control unit 18 by supplying it with an excessively high alternating voltage and current.

[0032] The electronic control unit 18 comprises a regulation module power supply 42. The power supply regulation module 42 is shown in detail in [Fig.2]. The power supply regulation module 42 comprises resistors 52, 53 and 54, an operational amplifier 56, a voltage reference 58 and a control element 60. The control element 60 is for example implemented by a MOS type transistor, or a bipolar transistor. The power supply regulation module 42 is here a shunt type regulation module controlled by the operational amplifier 56.

[0033] Resistors 53 and 54 are connected in series with each other, and in parallel with control element 60. A non-inverting terminal of operational amplifier 56 is connected between resistors 53 and 54, an inverting terminal of operational amplifier 56 is connected to voltage reference 58 and control element 60 is connected to the output of operational amplifier 56.

[0034] When the opening mechanism 12 is in the closing configuration, the input voltage Vin is applied to the input of the power supply regulation module 42, an output voltage Vout and an output current Lut are generated at the output of the power supply regulation module 42 and an internal current, of intensity called internal current Ir, flows in the power supply regulation module 42, more precisely in the control element 60. The internal current L is of identical phase to that of the input voltage Vin, that is to say phase shifted by ir / 2 with respect to the power supply voltage Ue.

[0035] The operational amplifier 56 operates as a comparator and compares a difference between a reference voltage Vref applied to the inverting terminal by the voltage reference 58 and a sample voltage Vs taken between the resistors 53 and 54.

[0036] In the event of variation of the input voltage Vin, the sample voltage Vs varies and becomes different from the reference voltage Vref. The operational amplifier 56 controls a more or less significant opening or closing of the control element 60 in order to vary the internal intensity Ir circulating in the control element 60 and thus, maintains the output voltage Vout constant.

[0037] The power supply regulation module 42 further comprises a current detector 62, for measuring the internal intensity Ir, visible in [Fig. 2]. The current detector 62 comprises a measuring device 63, an operational amplifier 64 connected to the measuring device 63 and an analog-to-digital converter 66, connected to the output of the operational amplifier 64. The measuring device 63 is for example a shunt resistor, or a current mirror assembly, and measures the internal intensity Ir-

[0038] The operational amplifier 64 amplifies the measurement made by the measuring device 63, and the analog-to-digital converter 66 converts the received signal into digital signal used by an information processing unit 90, included in the control unit 18. The internal intensity Ir is representative of the supply voltage Ue.

[0039] In particular, the information processing unit 90 is advantageously configured to determine the maxima of the internal intensity Ir. The determination of the maxima of the internal intensity Ir is for example carried out by detecting a cancellation or a change of sign of the derivative of the internal intensity Ir. The determination of the maxima of the internal intensity Ir makes it possible to deduce the moments when a phase ¢, of the internal intensity Ir is equal to Kir / 2 with K equal to 1 or 3 and, taking into account the phase shift caused by the supply capacitor 36, to deduce a phase C1L of the supply voltage Ue to within half a period. Indeed, since the internal intensity Ir is rectified, it is not possible to determine the exact value of K, and therefore to know whether a maxima of the internal intensity Ir corresponds to a maximum or a minimum of the supply voltage Ue.In the examples of figures 3 and 5, the internal intensity Ir is out of phase by ir / 2 with respect to the supply voltage Ue, so a maximum of internal intensity Ir occurs simultaneously with a zero crossing of the supply voltage Ue. In other words, at the moment when the phase <b, de l’intensité interne Ir est égale à Kir / 2, la phase . <e>u of the supply voltage is equal to Nir, with N equal to 0, 1 or 2, without the possibility of determining the exact value of N.

[0040] The detection of the maxima also allows the information processing unit 90 to determine a frequency of the supply voltage Ue. The frequency of the supply voltage is generally substantially equal to 50Hz, therefore a period of the supply voltage Ue is substantially equal to 20ms.

[0041] In a variant not shown, the information processing unit 90 is configured to determine the minima of the internal intensity Ir, that is to say the zero crossings of the internal intensity Ir. By zero crossing of a quantity, we mean the cancellation of the quantity.

[0042] In a variant not shown, the information processing unit 90 is configured to detect the extrema of the internal intensity, that is to say both the maxima and the zero crossings of the internal intensity Ir.

[0043] Advantageously, the information processing unit 90 is further configured to determine the effective value Uef of the supply voltage Ue from the measurement of the internal intensity Ir.

[0044] For example, the effective value Uef of the supply voltage Ue is obtained by the following formula:

[0045] Uef — Z X1 + K

[0046] With Z an equivalent impedance of the supply circuit 16, Z being known,

[0047] Irmax the maximum value of the internal intensity Ir,

[0048] K a constant such that K = Z x Imit + Vd + Vmit,

[0049] Vd being a dropout voltage of the power supply regulation module 42, which is known.

[0050] The information processing unit 90 further comprises a differential fault detection module 68, also called a detection module, connected to the conditioning unit 32.

[0051] The information processing unit 90 also comprises a control module 70, connected to the detection module 68 and connected to the trigger of the thyristor 26.

[0052] Advantageously and not shown, the information processing unit 90 is formed for example of a memory, and a processor, the processor being associated with the memory. Alternatively, the processor is a wired logic unit. The detection module 68, and the control module 70, are then each produced in the form of software, or a software brick, executable by the processor. The memory of the electronic control unit 18 is then capable of storing differential fault detection software, as well as, as an optional addition, control software.

[0053] Alternatively, each module 68 and 70 may be implemented in the form of programmed or wired logic units, using for example combinational and / or sequential logic, such as a microcontroller, an FPGA (Field Programmable Gate Array), or an integrated circuit, such as an ASIC (Application Specific Integrated Circuit). The processor is then capable of executing each of the software programs among the differential fault detection software and the control software.

[0054] A method for controlling the protection device 10 is described below, with reference to FIGS. 3 to 6. FIGS. 3 and 4 represent a first example in which the control method is implemented in a case where the effective voltage Uef is equal to 230V.

[0055] Advantageously, the device 10 is in an initial state, in which the contacts 23, 24 are in the closed configuration, the thyristor 26 is in the blocked state and the coil 21 is in the rest state. The electronic control unit 18 is powered by the power supply circuit 16. As a result, a low current, of the order of a few hundred microamperes, flows in the coil 21, but it is insufficient for the coil 21 to switch the contacts 23 and 24 into the open configuration, and is substantially zero. An intensity Ib flowing in the coil 21 is therefore substantially zero.

[0056] A step S100 consists of a measurement of the differential intensity Ld by the differential detector 14, and emission of the fault signal Sd.

[0057] A step S102 consists of a measurement of the internal intensity Ir by the current detector 62.

[0058] Advantageously, steps S100 and S102 are carried out continuously and alternatively or in addition, step S102 is carried out in parallel with step S100.

[0059] During a step S104, the detection module 68 detects a differential fault from the fault signal Sd. Advantageously, during step S104, the detection module 68 compares the fault signal Sd to a fault threshold Sthi. If the fault signal Sd is less than or equal to the fault threshold Sthi, then the process performs step S100 again and an iterative process is implemented.

[0060] When a differential fault is present in the load 5 or in the connectors between the protection device 10 and the load 5, the differential intensity Icd increases. This is visible at time A of [Fig.4]. The signal Sd, being the integral with respect to time of the differential intensity Icd, increases over time, until it becomes greater than the fault threshold Sthi. During step S104, the detection module 68 then detects a differential fault.

[0061] The information processing unit 90 determines the phase Chu of the supply voltage Ue from the internal intensity Ir measured by the current detector 62 during a step S106. Advantageously, the information processing unit 90 detects the maxima of the internal intensity Ir, and deduces therefrom the phase of the internal intensity Ir. Knowledge of the phase shift between the internal intensity Ir and the supply voltage Ue allows the information processing unit 90 to deduce therefrom the phase Ou of the supply voltage Ue.

[0062] Advantageously, during step S106, the information processing unit 90 also determines the frequency of the supply voltage Ue, and / or the effective voltage Uef from the internal intensity Ir.

[0063] In a variant not shown, step S106 is carried out in parallel with steps S100 and S102.

[0064] In a particularly advantageous manner, the information processing unit 90 compares the effective voltage Uef determined in step S106 with an effective value threshold during a step S107. If the effective voltage Uef is greater than the effective value threshold, a triggering phase <e>d is equal to Kir / 2, with K equal to 1 or 3. If the effective voltage Uef is less than or equal to the effective value threshold, then the trigger phase <e>d is equal to Nir, with N equal to 0, 1 or 2.

[0065] According to a first example, visible in [Fig.3], the triggering phase <e>d is equal to Kir / 2, with K equal to 1 or 3. The information processing unit 90 then determines during a step S108 whether the phase <e>u of the supply voltage Ue is equal to the trigger phase <e>d.

[0066] For this, advantageously, during step S108, the information processing unit 90 detects a maximum of the internal intensity Ir. When a maximum of the internal intensity Ir is detected, for example at an instant B in [Fig. 3], the supply voltage Ues is cancelled, that is to say passes through zero, in other words, the phase <e>u of the supply voltage Ue is equal to Nir with N equal to 0, 1 or 2. As mentioned previously, it is not possible to determine whether N is equal to 0, 1 or 2.

[0067] Knowing the frequency of the supply voltage Ue, the information processing unit 90 determines a synchronization duration Dsync from the instant when the maximum internal intensity Ir is detected, making it possible to obtain the phase <h(: de la tension d’alimentation Ue égale à la phase de déclenchement <e>d. The synchronization duration Dsync is in this example equal to a quarter of a period of the supply voltage Ue.

[0068] The information processing unit 90 waits for the synchronization duration Dsync to elapse. As soon as the synchronization duration Dsync has elapsed, the phase C1L of the supply voltage Ue equal to the trigger phase <e>d and the control module 70 controls the thyristor 26 in the on configuration during a control step SI 10, corresponding to an instant C in [Fig.3].

[0069] Advantageously, the control module 70 controls the thyristor 26 by emitting a control signal Sc. In the example of [Fig. 3], the control signal Sc is emitted on the trigger of the thyristor 26 in the form of at least one pulse, here two short pulses, of duration of the order of 1 to 2 ms. The rising edge of each of the two pulses is separated by a duration equal to half a period of the supply voltage Ue, for example 10 ms.

[0070] Indeed, it has been mentioned that it is not possible to know the value of N from the measurement of the internal intensity Ir. Thus, it is not possible to determine whether the voltage Ue is positive or negative from the measurement of Ir. Sending two pulses spaced by half a period of the voltage Ue makes it possible to turn on the thyristor 26 with certainty. Once triggered, the thyristor 26 remains on as long as the supply voltage Ue at its terminals is positive, which takes place between times C and D of [Fig.3], in other words, for a quarter of a period of the supply voltage Ue.

[0071] The intensity Ib in the coil 21 becomes equal to the intensity of the supply current between times C and D, in other words is equal to a positive quarter period of the intensity of the supply current, and generates a magnetic field which switches the contacts 23 and 24 into the opening configuration from the closing configuration. In other words, when the thyristor 26 is controlled in the conducting configuration, the coil 21 switches into the active state and switches the contacts 23 and 24 into the opening configuration at a time D visible in Figures 3 and 4. The current flowing between the source 3 and the load 5 is interrupted, the differential intensity Ld becomes zero, and the fault signal Sd decreases.

[0072] When the thyristor 26 is in the on configuration, it short-circuits the power supply circuit 16 and the electronic control unit 18. The capacitor 38 ensures the power supply of the information processing unit 90, which requires an intensity of the order of a few hundred microamperes to operate. As soon as the thyristor 26 is in the blocked configuration, the power supply circuit 16 again supplies the electronic control unit 18.

[0073] In a particularly advantageous and optional manner, the detection module 68 compares the fault signal Sd to a fault end threshold Sth2 in step S1 12. The fault end threshold Sth2 is, in the example of FIGS. 4 and 6, distinct from the fault threshold Sthi, but as a variant, is equal to the fault threshold Sthi.

[0074] If the fault signal Sd is greater than the end of fault threshold Sth2, then the information processing unit 90 determines whether the number of pulses N of the control signal Sc is greater than a maximum number of pulses Nmax in step SI 14. If this is not the case, the control module 70 performs the control step SI 10 again and an iterative operation is implemented.

[0075] If, during step SI 12, the detection module 68 determines that the fault signal Sd is less than or equal to the end of fault threshold Sth2, then this means that the differential fault has disappeared. The control module 70 performs step SI 16 during which it stops emitting the control signal Sc, corresponding to a time E in FIGS. 3 and 4. The thyristor 26 switches to the blocked configuration as soon as the supply voltage Ue becomes negative or remains in the blocked configuration if it was already in the blocked configuration. In the example of [Fig. 3], the thyristor 26 was already in the blocked configuration at time E. It therefore remains in the blocked configuration.

[0076] The intensity Ib which has passed through the coil 21a has therefore been limited to the minimum necessary to ensure the switching of the contacts 23 and 24 into the opening configuration.

[0077] If the number of pulses N of the control signal Sc is greater than the maximum number of pulses Nmax, the control module 70 also performs step SI 16, to prevent the coil 21 from being traversed by the current Ib for too long a duration and from being damaged.

[0078] Steps SI 12 to SI 16 are particularly advantageous in the case where the power supply circuit 16 is upstream of the contacts 23 and 24, that is to say between the source 3 and the contacts 23 and 24, and therefore continues to supply the electronic control unit 18 once the contacts 23, 24 are in the open configuration. They make it possible to determine when to stop controlling the thyristor 26.

[0079] Alternatively, in the case where the control element 26 is not a thyristor, and is for example a unidirectional current transistor, the control signal Sc is in the form of a plurality of pulses whose duration is equal to a quarter of a period of the supply voltage Ue and whose rising edge is separated from the rising edge of the following pulse by a duration equal to a half-period of the supply voltage Ue. The signal Sc is maintained for a predetermined control duration, or, optionally, as long as the fault signal Sd is greater than the end of fault threshold Sth2.

[0080] [Fig.5] represents a second example of implementation of the method for controlling the device 10, and corresponds to a case where the effective voltage Uef is equal to 50V. In step S107, the electronic control unit determines that the effective voltage Uef is strictly lower than the effective value threshold, then the triggering phase <e>d is equal to Nir, with N equal to 0, 1 or 2.

[0081] In a similar manner to what has been described previously, the information processing unit 90 then determines in step S108 whether the phase Chu of the supply voltage Ue is equal to the trigger phase <e>d.

[0082] For this, advantageously, during step S108, the information processing unit 90 detects a maximum of the internal intensity Ir. When a maximum of the internal intensity Ir is detected, for example at time B1 in [Fig.5], the supply voltage Ue is cancelled, that is to say passes through zero, in other words, the phase <e>u of the supply voltage Ue is equal to Nir with N equal to 0, 1 or 2, which corresponds to the trigger phase <e>d. In this case, the information processing unit 90 determines that the synchronization duration Dsync is zero and the control module 70 controls the thyristor 26 in the on configuration at the control step SI 10 by emitting the control signal Sc at the instant B1.

[0083] In the example of [Fig.5], the control signal Sc is in the form of a plurality of pulses of the order of 1 to 2 ms, here 6 pulses. Each rising edge of the pulse is separated from the rising edge of the following pulse by a duration equal to half a period of the supply voltage Ue, equal to 5 ms in the example of [Fig.5].

[0084] Thyristor 26 is on when it receives one of the pulses of the control signal Sc and the supply voltage Ue across its terminals is positive. It is therefore on for three half-periods of the supply voltage Ue during which the supply voltage Ue is positive. The current Ib in the coil 21 is then equal to the supply current when thyristor 26 is on. In other words, the current Ib is equal to three positive half-periods of the supply current.

[0085] Advantageously, the control module 70 emits two first pulses in the control step SI 10. The intensity Ib is not sufficient to switch the contacts 23, 24 into the opening configuration. The current flowing between the source 3 and the load 5 is not interrupted and the differential fault persists. In step SI 12, the information processing unit 90 determines that the fault signal Sd is greater than the end of fault threshold 8*2, performs step SI 14 and determines that the number of pulses is less than the maximum number of pulses. The control step SI 10 is performed again and an iterative operation is put into operation. work. In particular, the control module 70 continues to emit the signal Sc and then emits two new pulses at the control step SI 10.

[0086] If, during step SI 12, the detection module 68 determines that the fault signal Sd is less than or equal to the end of fault threshold Sth2, then this means that the differential fault has disappeared. The control module 70 performs step SI 16 during which it stops transmitting the control signal Sc, corresponding to the instant El in [Fig.5].

[0087] Alternatively, in the case where the control element 26 is not a thyristor, and is for example a current unidirectional transistor, the control signal Sc emitted in the control step SI 10 is in the form of a single continuous pulse. The signal Sc is maintained for a predetermined control duration, or, optionally, as long as the fault signal Sd is greater than the end of fault threshold Sth2.

[0088] As a variant applicable whatever the value of the effective voltage Uef, the steps SI 12, SI 14 and SI 16 are not carried out and the information processing unit 90 determines a duration of control of the thyristor 26 as a function of the effective voltage Uef, so that the coil 21 is traversed by a current Ib sufficient to ensure a switch to the open configuration of the contacts 23 and 24. The duration of the control signal Sc as a function of the effective voltage Uef is advantageously predetermined, for example imposed by the manufacturer of the device 10.

[0089] For example, if the effective voltage Uef is greater than the effective value threshold, the duration of the control signal Sc is slightly greater than half a period of the supply voltage Ue, more precisely equal to the sum of half a period of the supply voltage Ue and the duration of a pulse, so that the control signal Sc is formed of two pulses.

[0090] According to another example, if the effective voltage Uef is less than or equal to the effective value threshold, the duration of the control signal Sc is for example equal to the sum of two and a half periods and the duration of a pulse, so that the control signal Sc is formed of six pulses.

[0091] As a variant applicable regardless of the value of the effective voltage Uef, the fault signal Sd is generated digitally and is equal to the minimum between the integral of the differential current Icd and the fault threshold Sthi. In other words, the fault signal Sd saturates when it reaches the fault threshold Sthi. This allows the fault signal Sd to reach the end of fault threshold Sth2 more quickly when the differential fault is interrupted and the differential current Ld becomes zero, and therefore allows the transmission of the signal Sc to be interrupted as soon as possible.

[0092] The invention thus advantageously makes it possible to synchronize the control of the control element 26 on the supply voltage Ue, more particularly on the phase <e>u of the supply voltage Ue, in order to limit the current Ib flowing through the coil 21 at the intensity necessary to switch contacts 23 and 24 into the opening configuration. This limits wear on the coil. In addition, monitoring the disappearance of the fault signal ensures that the differential fault has definitely disappeared before stopping control of the control element 26. The device 10 is therefore made more reliable and the durability of the coil 21 is improved.< / e> < / e> < / e> < / e> < / e> < / e> < / e> < / e> < / e> < / e> < / e> < / e> < / e> < / e>

Claims

1. Claims Device (10) for differential electrical protection, configured to be connected between a source (3) and a load (5), the device (10) comprising: - a power supply circuit (16), configured to be connected to the source (3), and to be electrically powered by the source (3) under an alternating power supply voltage (Ue), variable over time; - contacts (23, 24), configured to switch into an opening configuration, in which the source (3) and the load (5) are isolated from each other, and into a closing configuration, in which the source (3) and the load (5) are connected to each other; - a differential detector (14), configured to measure a differential intensity (Icd) of a differential current flowing in the load (5) and emit a fault signal (Sd) representative of the differential intensity (Icd); - a coil (21), configured to switch between a rest state and an active state, in which the coil (21) switches the contacts (23, 24) into the opening configuration from the closing configuration; - a control element (26), configured to switch between an on state, in which the control element (26) allows power to be supplied to the coil (21) which then switches to the active state, and a blocked state, in which the control element (26) prevents power to the coil (21) which then switches to the rest state; and - an electronic control unit (18) comprising: • a power supply regulation module (42), connected to the power supply circuit (16), comprising a current detector (62), configured to measure an internal intensity (Ir) of an internal current flowing in the power supply regulation module (42), the internal intensity (Ir) being representative of the power supply voltage (Ue); and • an information processing unit (90) configured to determine a phase (Ou) of the voltage supply voltage (Ue) from the internal intensity (Ir) measured by the current detector (62), the information processing unit (90) comprising a detection module (68), configured to detect a differential fault from the fault signal (Sd) emitted by the differential detector (14) and a control module (70), configured to control the control element (26) in the on state when the detection module (68) detects a differential fault and the phase (Chu) of the supply voltage (Ue), determined by the information processing unit (90) from the internal intensity (Ir), is equal to a trigger phase (®d).

2. Device according to claim 1, wherein the information processing unit (90) determines that the phase (Chu) of the supply voltage (Ue) is equal to the trigger phase ( <bd), en détectant un extremum de l’intensité interne, et en attendant qu’une durée de synchronisation (Dsync), mesurée à partir du moment où l’extremum de l’intensité interne est détecté, soit écoulée.

3. Device (10) according to any one of claims 1 or 2, wherein the information processing unit (90) is further configured to determine an effective value (Uef) of the supply voltage (U e) from the internal intensity (Ir), and wherein when the effective value (Uef) of the supply voltage (Ue) is less than or equal to an effective value threshold, the triggering phase ( <e>d) is equal to Nir with N equal to 0, 1 or 2, and when the effective value (Uef) of the supply voltage (Ue) is greater than the effective value threshold, the triggering phase ( <e>d) is equal to Kir / 2, with K equal to 1 or 3.

4. Device (10) according to claim 3, wherein the information processing unit (90) is further configured to calculate a control duration of the control element (26) in the state passing through the control module (70) as a function of the effective value (Uef) of the supply voltage (Ue).

5. Device (10) according to any one of the preceding claims, wherein: - the contacts (23, 24) are connected between the power supply circuit (16) and the load (5); - the detection module (68) is further configured to compare the fault signal (Sd) with a fault threshold (Sthi), a differential fault being detected when the fault signal (Sd) is greater than the fault threshold (Sthi), and is further configured to compare the fault signal (Sd) with a fault end threshold (Sth2); and - the control module (70) is further configured to control the control element (26) in the blocked state when the fault signal (Sd) is less than or equal to the fault end threshold (Sth2), the control module (70) having controlled the control element (26) in the conducting state.

6. Device (10) according to any one of the preceding claims, wherein the control module (70) is configured to control the control element (26) in the on state by emitting a control signal (Sc) in the form of at least one pulse.

7. Device (10) according to claim 6, in which the control signal (Sc) is in the form of a plurality of pulses, each rising edge of the pulse being separated from the rising edge of the following pulse by a duration equal to half a period of the supply voltage (Ue).

8. Device (10) according to claim 6, in which the control signal (Sc) is in the form of two pulses, the rising edge of the two pulses being separated by a duration equal to half a period of the supply voltage (Ue).

9. Electrical installation (1) comprising a source (3), a load (5) and a differential electrical protection device (10) according to any one of the preceding claims.

10. Method for controlling a differential electrical protection device (10) according to any one of claims 1 to 8, the method comprising at least the following steps: - measurement (S 100) of the differential intensity (Icd) circulating in the load (5) by the differential detector (14) and emission of the fault signal (Sd); - measurement (S 102) of the internal intensity (Ir) by the detector of current(62); - detection (S 104) by the detection module (68) of a differential fault from the fault signal (Sd) emitted by the differential detector (14); - determination (S 106) of the phase (Ou) of the voltage power supply (Ue) from the internal intensity (Ir) measured by the current detector (62), by the information processing unit (90); and - control (SI 10) of the control element (26) in the passing state by the control module (70), the detection module (68) having detected a differential fault and the phase (Ou) of the supply voltage (Ue), determined by the electronic control unit from the internal intensity (Ir), being equal to the triggering phase (Od).

11. Method according to claim 10, in which the trigger phase (Od) is chosen from the following group: Nir, N being equal to 0, 1 or 2; and, Kir / 2, K being equal to 1 or 3.< / e> < / e>

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