Electrical equipment for protection against at least one overload type fault

Abstract

Electrical apparatus for protection against at least one overload type fault The invention relates to an electrical apparatus for protection against at least one overload type fault comprising: a phase current line (L), a current transformer (1), a cut-off unit (2), a protection trigger (6) connected to an actuator (7) and comprising a control member (8), characterized in that: the protection trigger (6) is configured to be supplied with voltage independently of the network voltage by the energy coming from said current transformer (1) further configured to transform the current flowing on the phase current line (L) into voltage, the protection trigger (6) comprises a thermal memory stage (9) and a tripping stage (10) comprising said control member (8),the thermal memory stage (9) being electrically connected upstream of the trigger stage (10) and being configured to delay the power supply of the trigger stage (10) according to a heating time constant representative of the heating of a thermal detection bimetallic strip and according to a cooling time constant representative of the cooling of the thermal detection bimetallic strip. Figure to be published with the abstract: Fig. 1,

Description

Title of the invention: Electrical apparatus for protection against at least one overload-type fault

[0001] The present invention relates to the field of electrical protection equipment against at least one overload type fault.

[0002] Usually in an electrical device for protection against at least one overload type fault, such as a circuit breaker for example of the MCB (Miniature Circuit Breaker) type or a differential circuit breaker for example of the RCBO (Residual Current Circuit Breaker with Overload protection) type, an overload type fault is detected by a thermal converter of the bimetallic strip type. However, thermal protection by means of a bimetallic strip is responsible on average for forty percent of the energy dissipated in this type of electrical protection device. When these electrical protection devices are in operation in an electrical panel, this results in a loss of power and thermal heating, which is not desirable.

[0003] Document EP1912238A1 proposes a cut-off circuit which includes a shunt-type current sensor and a processor having an overload protection function. However, this electronic solution for replacing a bimetallic strip has the disadvantage of requiring a power supply dependent on the network voltage to operate the electronics and in particular a microcontroller. In addition, the shunt is similar to a bimetallic strip in terms of energy dissipation.

[0004] The present invention aims to overcome at least one of these drawbacks and aims to provide a solution for detecting and triggering in the event of an overload-type fault not using a thermal converter with a bimetallic strip, and which is independent of the network voltage and which at least allows the energy dissipation of the electrical protection equipment to be reduced.

[0005] To this end, the invention relates to an electrical device for protection against at least one overload-type fault comprising at least:

[0006] - a phase current line between a first connection terminal and a second connection terminal,

[0007] - a current sensor comprising a current transformer for measuring the current flowing through the phase current line and to emit a signal representative of the phase current image,

[0008] - a cut-off unit comprising a first set of separable contacts comprising a first fixed contact and a first movable contact on the phase current line,

[0009] - a protection trigger electrically connected upstream of it to the trans current former and downstream of it to an actuator and comprising at least one control member, the protection trigger being configured to at least process said signal representative of the phase current image and where appropriate control said actuator via said control member at least in the event of the occurrence of an overload type fault,

[0010] - said actuator being configured to be controlled at least by said member of control for mechanically actuating the opening of said first set of separable contacts at least in the event of the occurrence of an overload type fault,

[0011] said electrical protection apparatus is characterized in that:

[0012] - the protection trigger is configured to be supplied with independent voltage during the network voltage by the energy coming from said current transformer further configured to transform the current flowing on the phase current line into voltage,

[0013] - the protection trigger comprises at least one thermal memory stage and a trigger stage comprising said control member, the thermal memory stage being electrically connected upstream of the trigger stage and being configured to delay the power supply of the trigger stage at least according to a heating time constant representative of the heating of a thermal detection bimetallic strip and at least according to a cooling time constant representative of the cooling of the thermal detection bimetallic strip.

[0014] The invention will be better understood from the following description, which relates to several preferred embodiments, given as non-limiting examples, and explained with reference to the appended schematic drawings, in which:

[0015] [Fig-1] [Fig.l] represents a diagram of the operation of a device electrical protection in a first variant embodiment of the invention,

[0016] [Fig.2] [Fig.2] represents a diagram of the operation of an electrical protection device in a second variant embodiment of the invention,

[0017] [Fig.3] [Fig.3] represents the electrical diagram of the protection trigger in the first embodiment variant and the second embodiment variant of the invention,

[0018] [Fig.4] [Fig.4] represents a diagram of the operation of an electrical protection device in a third variant embodiment of the invention,

[0019] [Fig.5] [Fig.5] represents a diagram of the operation of an electrical protection device in a fourth variant embodiment of the invention,

[0020] [Fig.6] [Fig.6] represents a diagram of the operation of an electrical protection device in a fifth variant embodiment of the invention,

[0021] [Fig.7] [Fig.7] represents the electrical diagram of the protection trigger in the third embodiment variant, the fourth embodiment variant and the fifth alternative embodiment of the invention,

[0022] [Fig.8] [Fig.8] represents a micro-bimetallic actuator in an initial state,

[0023] [Fig.9] [Fig.9] represents the micro-bimetallic actuator in an intermediate state, and

[0024] [Fig. 10] [Fig. 10] shows the micro-bimetallic actuator in a triggered state.

[0025] Electrical protection equipment against at least one overload type fault includes at least:

[0026] - a phase current line L between a first connection terminal and a second connection terminal,

[0027] - a current sensor comprising a current transformer 1 for measuring the current flowing through the phase current line L and to emit a signal representative of the image of the phase current L,

[0028] - a cut-off unit 2 comprising a first set of separable contacts 3 comprising a first fixed contact 4 and a first movable contact 5 on the phase current line L,

[0029] - a protection trigger 6 electrically connected upstream of it to the trans current former 1 and downstream of it to an actuator 7 and comprising at least one control member 8, the protection trigger 6 being configured to at least process said signal representative of the phase current image L and where appropriate to control via said control member 8 said actuator 7 at least in the event of the occurrence of an overload type fault,

[0030] - said actuator 7 being configured to be controlled at least by said member of control 8 for mechanically actuating the opening of said first set of separable contacts 3 at least in the event of the occurrence of an overload type fault.

[0031] According to the invention, said electrical protection apparatus is characterized in that:

[0032] - the protection trigger 6 is configured to be supplied with independent voltage during the network voltage by the energy coming from said current transformer 1 further configured to transform the current flowing on the phase current line L into voltage,

[0033] - the protection trigger 6 comprises at least one thermal memory stage 9 and a trigger stage 10 comprising said control member 8, the thermal memory stage 9 being electrically connected upstream of the trigger stage 10 and being configured to delay the power supply of the trigger stage 10 at least according to a heating time constant representative of the heating of a thermal detection bimetallic strip and at least according to a cooling time constant representative of the cooling of the thermal detection bimetallic strip.

[0034] Advantageously, in this solution the current transformer 1 makes it possible to perform a current measurement function and an electrical power supply function of the protection trigger 6. Indeed, the current transformer 1 makes it possible to power the protection trigger 6 and has the advantage of not dissipating energy to measure the current flowing in the phase current line L. Preferably, the power supply of the protection trigger 6 can thus be done exclusively by this means and without recourse to the network voltage or to an auxiliary source. Furthermore, the protection trigger 6 comprises at least one thermal memory stage 9 which makes it possible to reproduce in a substantially equivalent manner the operating characteristics of a thermal detection bimetallic strip and in particular its behavior during its heating and cooling.Advantageously, the adjustment of the parameters can be done electronically, that is to say by modifying the electronic components of the thermal memory stage 9, which makes it possible to develop the thermal memory stage 9 according to the type of electrical protection equipment desired and the desired rating.

[0035] Preferably, the thermal memory stage 9 comprises at least one RC type circuit, comprising at least a first resistor R4 in series with a first capacitor C3 and a second resistor R5 in parallel with the first capacitor C3, the response times of which correspond respectively to the heating time constant and to the cooling time constant.

[0036] Advantageously, the thermal memory stage 9 is produced using an analog type electrical circuit and which therefore does not involve a microcontroller, which has the advantage of requiring basic and inexpensive analog electronic components. The heating time constant is achieved at least by the association of the first resistor R4 with the first capacitor C3, while the cooling time constant is achieved by the association of the second resistor R5 with the first capacitor C3.

[0037] Preferably, said thermal memory stage 9 is configured to delay the power supply of the trigger stage 10 at least according to a first heating time constant corresponding to the heating of the thermal detection bimetallic strip with a current value preferably less than twice the nominal current and a second heating time constant corresponding to the heating of the thermal detection bimetallic strip with a current value preferably greater than twice the nominal current, the first time constant being greater than the second time constant.

[0038] Advantageously, the thermal memory stage 9 is configured to operate differently depending on the current value. For so-called low current values, preferably less than twice the nominal current, the thermal memory stage 9 is configured to have a response time corresponding to the first heating time constant and for so-called high current values, preferably greater than twice the rated current, the thermal memory stage 9 is configured to have a response time corresponding to the second heating time constant, with the first time constant greater than the second time constant. As a result, triggering will occur more quickly for so-called high current values ​​than for so-called low current values.

[0039] Preferably, the RC type circuit further comprises a branch parallel to the first resistor R4 comprising at least one Zener diode D8 and a third resistor R3 connected in series and whose characteristics correspond to the first and second heating time constants.

[0040] Advantageously, for so-called high current values, the thermal memory stage 9 is configured to have a response time corresponding to the second heating time constant compared to the first heating time constant, which will allow a much shorter charging time of the first capacitor C3 than for so-called low current values.

[0041] Preferably, the trigger stage 10 preferably comprises a voltage detector 12 associated with a time delay.

[0042] Advantageously, the voltage detector 12 makes it possible to detect when the output voltage of the trigger stage 10 corresponds to the appearance of an overload type fault, by comparison with a predetermined threshold voltage value, and in this case to emit a trigger output voltage which will make it possible to control the control member 8. The time delay makes it possible to guarantee that sufficient energy is available to trigger the control member 8 or that the power supply stage 11 described below has been able to be charged before triggering. The time delay is preferably carried out by a third capacitor C4 connected to the voltage detector 12.

[0043] Preferably, said actuator 7 is an electromagnetic actuator 7' and is configured at least to be controlled by the control member 8 of the trigger stage 10, being controlled by an electrical control signal coming from the control member 8 at least in the event of the occurrence of an overload type fault.

[0044] In this advantageous configuration, in the event of the occurrence of an overload-type fault, the control member 8 controls the change of state of the electromagnetic actuator 7', which passes from an initial state to a triggered state, by emitting the electrical control signal, which has the consequence that the electromagnetic actuator 7' in turn actuates the opening of said first set of separable contacts 3.

[0045] Preferably, the protection trigger 6 comprises a power supply stage 11 parallel to the thermal memory stage 9 and being electrically connected upstream of the trigger stage 10 and configured to store the energy coming from the first current transformer 1 and to power the trigger stage 10 from said stored energy to control the control member 8 in the event of an overload type fault occurring.

[0046] Advantageously, the power supply stage 11 makes it possible to store the energy coming from the current transformer 1 and which is necessary to power the triggering stage 10 so as to make it possible to trigger the electromagnetic actuator 7' using the control member 8 in the event of the occurrence of an overload type fault.

[0047] Preferably, said control member 8 preferably comprises a power transistor of the thyristor, bipolar transistor or field effect transistor type.

[0048] Advantageously, this type of bistable control member 8 has the advantage of allowing the energy stored in the power supply stage 11 to be completely transferred.

[0049] Preferably, said electrical protection apparatus further comprises a neutral current line N and a differential current sensor 14 crossed by the phase current line L and the neutral current line N to further measure the difference in current flowing between said phase current line L and the neutral current line N and emit an acquisition signal representative of the difference in current between the phase current line L and the neutral current line N and a differential fault detection unit 15 connected upstream of the latter to the differential current sensor 14 so as to be powered independently of the network voltage and connected downstream of the latter to the electromagnetic actuator 7' to control it in the event of the occurrence of a differential fault.

[0050] In this advantageous configuration, in the event of the occurrence of a differential fault, the differential fault detection unit 15 controls the change of state of the electromagnetic actuator 7', which passes from an initial state to a triggered state, which has the consequence that the electromagnetic actuator 7' in turn actuates the opening of said first set of separable contacts 3. Thus, said electrical protection apparatus provides at least one protection against overload or differential faults. The electromagnetic actuator 7' is thus either controlled by said control member 8 in the event of the occurrence of an overload fault, or by the differential fault detection unit 15 in the event of the occurrence of a differential fault. This differential function has the advantage of not depending on the network voltage to operate.Finally, in this configuration, the 7' electromagnetic actuator is shared for the implementation of protection against overload or differential type faults, which has the advantage of reducing the size and therefore offering a compact solution.

[0051] Preferably, the control member 8 comprises at least one switch, preferably with low impedance, connected in series with said actuator 7, the switch and said actuator 7 being mounted in parallel with a magnetic detection coil 13 of the phase line L and in the event of an overload type fault the switch is configured to be switched into a passing state to authorize the supply of said actuator 7 by the voltage drop coming from the magnetic detection coil 13.

[0052] In this alternative configuration, the energy required to power the trigger stage 10 comes from the energy of the current transformer 1, but this has not been previously stored, and allows the closing of the low impedance switch in the event of an overload type fault which becomes conductive. Consequently, when the circuit containing the actuator 7 is closed because the switch has become conductive, then the magnetic detection coil 13 provides the necessary energy in the form of a voltage drop to the actuator 7 to allow its change of state and for it to pass from an initial state E1 to a triggered state E3, which has the consequence that the actuator 7 in turn actuates the opening of said first set of separable contacts 3.

[0053] Preferably, the protection trigger 6 is devoid of power supply means configured to store the energy coming from the first current transformer 1

[0054] Advantageously, this configuration simplifies the protection trigger 6.

[0055] Preferably, said control member 8 comprises at least one power transistor and preferably at least one FET field effect transistor.

[0056] Advantageously, this type of control member 8 forming said switch has the advantage of having a low impedance.

[0057] Preferably, said actuator 7 is a 7” micro-bimetallic actuator.

[0058] Said actuator 7 may alternatively consist of an electromagnetic actuator 7'.

[0059] Advantageously, it is possible to use two types of actuators 7.

[0060] Preferably, the electrical protection apparatus further comprises a neutral current line N and a differential current sensor 14 crossed by the phase current line L and the neutral current line N to further measure the current difference flowing between said phase current line L and the neutral current line N and emit an acquisition signal representative of the current difference between the phase current line L and the neutral current line N and a differential fault detection unit 15 connected upstream thereof to the differential current sensor 14 so as to be powered independently of the network voltage and connected downstream thereof to the electromagnetic actuator 7' via said control member 8 to control the electromagnetic actuator 7' in the event of the occurrence of a differential fault.

[0061] In this advantageous configuration in the event of the appearance of a dif type fault differential, the differential fault detection unit 15 controls the change of state of the electromagnetic actuator 7' via the control member 8, which changes from an initial state to a triggered state, which has the consequence that the electromagnetic actuator 7' in turn actuates the opening of said first set of separable contacts 3. Thus, said electrical protection apparatus provides at least protection against overload or differential type faults. The electromagnetic actuator 7' is thus either controlled by said control member 8 in the event of the occurrence of an overload type fault, or by the differential fault detection unit 15 in connection with said control member 8 in the event of the occurrence of a differential fault. This differential function has the advantage of not depending on the network voltage to operate.Finally, in this configuration, the 7' electromagnetic actuator is shared for the implementation of protection against overload or differential type faults, which has the advantage of reducing the size and therefore offering a compact solution.

[0062] The protection trigger 6 preferably comprises a filtration and overvoltage protection stage 16 connected upstream of the thermal memory stage 9.

[0063] Advantageously, this filtration and overvoltage protection stage 16 makes it possible to avoid damaging the thermal memory stage 9 and the trigger stage 10 and, where appropriate, the power supply stage 11 in the event of high-frequency disturbances coming from outside and in the event of overvoltages.

[0064] The protection trigger 6 preferably comprises at least one electronic card (not shown) comprising at least the thermal memory stage 9 and the trigger stage 10.

[0065] The electrical apparatus for protection against at least one overload-type fault may comprise one or more phase current lines L. It may further comprise a neutral current line N.

[0066] Preferably, the current transformer 1 comprises at least the toroid surrounding only the phase current line L. The protection trip device 6 is preferably configured to be powered exclusively by the energy coming from said current transformer 1 and thus is not powered by the network voltage or an auxiliary source.

[0067] The cut-off unit 2 comprises the first set of separable contacts 3 which comprises the first fixed contact 4 and the first movable contact 5 on the phase current line L. The first movable contact 5 can be mounted on a contact carrier (not shown) and be part of a mechanical lock 18 which is actuable by the actuator 7.

[0068] The protection trigger 6 comprises at least said thermal memory stage 9 and said trigger stage 10. The protection trigger 6 is connected to the current transformer 1 which is also the current sensor which makes it possible to supply the protection trigger 6 and to transmit the signal representative of the image of the phase current L to the latter.

[0069] In preferred and non-limiting examples illustrated by figures 1 to 7, the protection trigger 6 further comprises said filtration and overvoltage protection stage 16, which is connected upstream of the thermal memory stage 9 (the latter possibly being connected in parallel to the power supply stage 11), which is connected upstream of the trigger stage 10.

[0070] In these preferred examples illustrated by figures 1 to 7, the protection trigger 6 further comprises a load impedance 19 comprising a fourth resistor RI which is connected downstream of the current transformer 1 and is connected upstream of the filtration and overvoltage protection stage 16.

[0071] The load impedance 19, the filtration and overvoltage protection stage 16, the thermal memory stage 9 and the trigger stage 10 are preferably integrated on said at least one electronic card, for example of the PCB A type.

[0072] As illustrated in Figures 3 and 7, the filtering function of the filtering and overvoltage protection stage 16 can be performed by a circuit comprising fifth and sixth filtering capacitors C1, C2 which are connected in parallel.

[0073] As illustrated in Figures 3 and 7, the protection function of the filtration and overvoltage protection stage 16 can be achieved by a circuit comprising fifth, sixth and seventh voltage clipping diodes D1, D2, D3.

[0074] As illustrated in Figures 3 and 7, the thermal memory stage 9 may comprise the RC type circuit, comprising the first branch comprising the first diode D4 in series with the first resistor R4, the first branch is associated with the first capacitor C3 and with the second resistor R5 in parallel with the first capacitor C3. The thermal memory stage 9 further comprises the second branch parallel to the first branch comprising the Zener diode D8, the second diode D9 and the third resistor R3 connected in series.

[0075] In a preferred and non-limiting example illustrated in [Fig.3], if present, the power supply stage 11 comprises the third diode D5 associated with the second capacitor C8.

[0076] As illustrated in Figures 3 and 7, said trigger stage 10 preferably comprises the voltage detector 12, at least one bistable trigger member and said at least one control member 8.

[0077] As illustrated in Figures 3 and 7, the voltage detector 12 makes it possible to detect when the voltage at the output of the trigger stage 10 corresponds to the appearance of an overload type fault, by comparison with a predetermined threshold voltage value. completed. The voltage detector 12 may include a comparator-type circuit.

[0078] Preferably and as illustrated in Figures 3 and 7, said at least one bistable triggering member is downstream of the voltage detector 12 and upstream of said control member 8 and comprises a circuit comprising at least one fourth diode D6 in series with a fourth capacitor C6 which are configured to control said control member 8.

[0079] The control member 8 preferably comprises said at least one power transistor of the thyristor, bipolar transistor ([Fig.3]) or field effect transistor ([Fig.7]) type.

[0080] As illustrated in [Fig.3], if the control member 8 comprises said at least one transistor of the bipolar transistor type, the latter is electrically connected to the electromagnetic actuator 7'. In the event of the occurrence of an overload type fault, the bipolar transistor becomes conductive and allows the current to conduct, which amounts to emitting the electrical control signal to control the change of state of the electromagnetic actuator 7', the electromagnetic actuator 7' thus being powered by the energy stored in the power supply stage 11 via the current transformer 1.

[0081] As illustrated in [Fig.7], if the control member 8 comprises said at least one FET field effect transistor, for example a MOSFET, then the control member 8 preferably comprises a first set of FET field effect transistors and a second set of FET field effect transistors which are preferably connected in series, for example in a head-to-tail manner. In the event of the occurrence of an overload type fault, the field effect transistors change from a non-conducting state to an conducting state, which closes the circuit of the actuator 7, the actuator 7 is thus powered directly by the voltage drop generated by the fault and not via the energy coming from the current transformer 1, which causes its change of state.

[0082] For example, the actuator 7 may be the electromagnetic actuator 7' (Figures 1 to 3, 5 to 7) or the micro-bimetallic actuator 7” (Figures 4, 7 to 10), and is bistable and can therefore change state by passing from an initial state El to a triggered state E3. In all cases, when an overload-type fault occurs, the actuator 7 is arranged to mechanically actuate the opening of said first set of separable contacts 3 and to pass from the initial state El to the triggered state E3. This actuation can be done by means of the mechanical lock 18 of the cut-off unit 2 in connection with the contact holder carrying the first movable contact 5. Indeed, the actuator 7 preferably comprises a button or rod 19 (Figures 8 to 10) in mechanical connection with the mechanical lock 18. In the event of the occurrence of an overload-type fault, the button or rod 19 of the actuator 7 is moved towards the mechanical lock 18 of so as to move the first movable contact 5 away from the first fixed contact 4 and thus cause the opening of said first set of separable contacts 3.

[0083] The electromagnetic actuator 7' illustrated in figures 1 to 3, 5 to 7 has the advantage that it can be shared to detect a differential fault.

[0084] The 7” micro-bimetallic actuator illustrated in Figures 4, 7 to 10 has the advantage of being more compact than a 7' electromagnetic actuator. However, it is not compatible with the examples illustrated in Figures 1 to 3.

[0085] According to a possible embodiment illustrated in figures 8 to 10 but which is not limiting, the micro-bimetallic strip actuator 7” comprises a housing 20 in which is contained a micro-bimetallic strip 21 which under certain current flow conditions can be deformed, a compression spring 22a and a bistable lever 22b and the rod 19 can be partly projecting outside the housing 20. The micro-bimetallic strip 21 is on the one hand connected by a first end 21a to a first electrical connection element 23 preferably in the form of a pin and by means of a solder point 24 or equivalent and is on the other hand connected by a second free end 21b to a second electrical connection element 25 preferably in the form of a pin and by means of a flexible electrical conductor 26 of braid type or equivalent.The first and second electrical connection elements 23, 25 are configured to be electrically connected to the protection trigger 6. Under the effect of the deformation of the micro-bimetallic strip 21, the second free end 21b of the micro-bimetallic strip 21 can actuate the bistable lever 22b, in turn actuating the rod 19 which passes from a retracted position PR in the housing 20 to an extended position PS.

[0086] In the examples illustrated by Figures 4 to 6, the magnetic detection coil 13 is mounted on the phase current line L and also makes it possible to detect short-circuit type faults. The voltage drop necessary for triggering the micro-bimetallic actuator 7” ([Fig.4]) or the electromagnetic actuator 7' (Figures 5 and 6) can be taken from a component other than the magnetic detection coil 13.

[0087] As shown in Figures 2 and 6, the differential current sensor 16 is preferably a torus surrounding the phase current line L and the neutral current line N.

[0088] The differential fault detection unit 15 illustrated in figures 2 and 6 is optional and is provided to process the acquisition signal representative of the current difference between the phase current line L and the neutral current line N and, if necessary, to control via said control member 8 or not said electromagnetic actuator 7' in the event of the appearance of a differential fault.

[0089] The electrical apparatus for protection against at least one overload type fault preferably comprises a housing (not shown) in which the different components.

[0090] The housing preferably has a generally parallelepiped shape with a width, that is to say the distance between the main faces, equal to an integer number of times a predetermined distance, called module, generally worth approximately 18 millimeters.

[0091] Thanks to this advantageous arrangement, the format of the housing is modular and this results in modular protection equipment.

[0092] The electrical apparatus for protection against at least one overload type fault is preferably a circuit breaker, for example of the MCB (Miniature Circuit Breaker) type, or a differential circuit breaker, for example of the RCBO (Residual Current Circuit Breaker with Overload protection) type, independent of the network voltage.

[0093] [Fig.l] represents a diagram of the operation of the electrical protection apparatus in a first variant embodiment of the invention which makes it possible to ensure only a protection function against overload type faults without resorting to a bimetallic strip. The electrical protection apparatus comprises the neutral current line N and the phase current line L provided with the first set of separable contacts 3 actuable by the mechanical lock 18 associated with the actuator 7 and surrounded by the current transformer 1 connected to the protection trip unit 6. The protection trip unit 6 has the particularity of comprising the power supply stage 11 in addition to the load impedance 19, said filtration and overvoltage protection stage 16, said thermal memory stage 9 and said tripping stage 10.In this case, the actuator 7 consists of the electromagnetic actuator 7' of the relay type which is controlled by said at least one control member 8 in the event of the occurrence of an overload type fault.

[0094] [Fig. 2] represents a diagram of the operation of the electrical protection apparatus in a second alternative embodiment of the invention, which makes it possible to provide either a protection function against overload-type faults without using a bimetallic strip, or a protection function against a differential fault. The electrical protection apparatus of this second alternative embodiment of the invention is distinguished from the first alternative embodiment of the invention by the fact that it further comprises the differential current sensor 14 in the form of a torus around the phase current line L and the neutral current line N and the differential fault detection unit 15. In this case the electromagnetic actuator 7' of relay type is controlled by said at least one control member 8 in the event of the occurrence of an overload-type fault or by the differential fault detection unit 15 in the event of the occurrence of a differential fault.

[0095] [Fig. 3] represents the electrical diagram of the protection trigger 6 in the first variant embodiment and the second variant embodiment of the invention. In this configuration, the thermal memory stage 9 comprises the RC type circuit, comprising the first diode D4 and the first resistor R4 in series with the first capacitor C3 and the second resistor R5 in parallel with the first capacitor C3, and furthermore the branch parallel to the first resistor R4 comprising the second diode D9, the Zener diode D8 and the third resistor R3 in series with the first capacitor C3. The power supply stage 11 is also present in this configuration and is in parallel with the thermal memory stage 9 and comprises the third diode D5 associated with the second capacitor C8. The trigger stage 10 preferably comprises a voltage detector 12 associated with the time delay which is carried out by the third capacitor C4 connected to the voltage detector 12.The trigger stage 10 comprises the circuit comprising the fourth diode D6 in series with the fourth capacitor C6 to control two bipolar transistors Q1, Q2 forming the control member 8.

[0096] [Fig.4] represents a diagram of the operation of the electrical apparatus of protection in a third variant embodiment of the invention which makes it possible to ensure only a protection function against overload type faults without resorting to a bimetallic strip. The electrical protection apparatus comprises the neutral current line N and the phase current line L provided with the first set of separable contacts 3 actuable by the mechanical lock 18 associated with the actuator 7, the magnetic detection coil 13 and surrounded by the current transformer 1 connected to the protection trip unit 6. The protection trip unit 6 has the particularity of not comprising the power supply stage 11 in addition to the load impedance 19, said filtration and overvoltage protection stage 16, said thermal memory stage 9 and said tripping stage 10. The control member 8 and said actuator 7 are mounted in parallel with the magnetic detection coil 13 of the phase line L.In this case the actuator 7 consists of the micro-bimetallic actuator 7” which in the event of an overload type fault is powered by the voltage drop coming from the magnetic detection coil 13 due to the fact that said at least one switch of the control member 8 has switched to a passing state.

[0097] [Fig. 5] represents a diagram of the operation of the electrical protection apparatus in a fourth alternative embodiment of the invention which makes it possible to ensure only a protection function against overload-type faults without resorting to a bimetallic strip. The electrical protection apparatus of this fourth alternative embodiment of the invention is distinguished from the third alternative embodiment of the invention by the fact that in this case the actuator 7 consists of the electromagnetic actuator 7' of the relay type which, in the event of an overload-type fault, is powered by the voltage drop coming from the magnetic detection coil 13 due to the fact that said at least one switch of the control member 8 has switched to a conducting state.

[0098] [Fig. 6] shows a diagram of the operation of the electrical protection apparatus in a fifth embodiment of the invention, which makes it possible to provide either a protection function against overload-type faults without using a bimetallic strip, or a protection function against a differential fault. The electrical protection apparatus of this fifth embodiment of the invention differs from the fourth embodiment of the invention in that it further comprises the differential current sensor 14 in the form of a torus around the phase current line L and the neutral current line N and the differential fault detection unit 15.In this case, the electromagnetic actuator 7' of relay type is controlled by said at least one control member 8 in the event of the occurrence of an overload type fault or by the differential fault detection unit 15 in connection with said at least one control member 8 in the event of the occurrence of a differential fault.

[0099] [Fig.7] represents the electrical diagram of the protection trip device 6 in the third embodiment variant, the fourth embodiment variant and the fifth embodiment variant of the invention. In this configuration, the thermal memory stage 9 comprises the RC type circuit, comprising the first diode D4 and the first resistor R4 in series with the first capacitor C3 and the second resistor R5 in parallel with the first capacitor C3, and furthermore the branch parallel to the first resistor R4 comprising the second diode D9, the Zener diode D8 and the third resistor R3 in series with the first capacitor C3. The trigger stage 10 preferably comprises the voltage detector 12 associated with the time delay which is carried out by the third capacitor C4 connected to the voltage detector 12.The trigger stage 10 comprises the circuit comprising the fourth diode D6 in series with the fourth capacitor C6 to control two field effect transistors M1, M2 forming the control member 8.

[0100] [Fig.8] represents the micro-bimetallic strip actuator 7” in the initial state EL. The micro-bimetallic strip 21 does not undergo any deformation and the rod 19 is in the retracted position PR in the housing 20.

[0101] [Fig.9] represents the micro-bimetallic strip actuator 7” in the intermediate state E2. Under the effect of the deformation of the micro-bimetallic strip 21, the second free end 21b of the micro-bimetallic strip 21 actuates the bistable lever 22b, in turn actuating the rod 19 which will move from the retracted position PR in the housing 20 in which it is located to the extended position PS.

[0102] [Fig. 10] shows the micro-bimetallic strip actuator 7” in the triggered state E3. Following the deformation of the micro-bimetallic strip 21, the second free end 21b of the micro-bimetallic strip 21 has actuated the bistable lever 22b and then the rod 19 which is now in the extended position PS.

[0103] Of course, the invention is not limited to the embodiments described and shown in the attached drawings. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without departing from the scope of protection of the invention.

Claims

1. Claims Electrical equipment for protection against at least one overload-type fault comprising at least: - a phase current line (L) between a first connection terminal and a second connection terminal, - a current sensor comprising a current transformer (1) for measuring the current flowing through the phase current line (L) and for emitting a signal representative of the image of the phase current (L), - a cut-off unit (2) comprising a first set of separable contacts (3) comprising a first fixed contact (4) and a first movable contact (5) on the phase current line (L), - a protection trigger (6) electrically connected upstream of the latter to the current transformer (1) and downstream of the latter to an actuator (7) and comprising at least one control member (8), the protection trigger (6) being configured to at least process said signal representative of the phase current image (L) and, if necessary, control via said control member (8) said actuator (7) at least in the event of the occurrence of an overload type fault, - said actuator (7) being configured to be controlled at least by said control member (8) to mechanically actuate the opening of said first set of separable contacts (3) at least in the event of the occurrence of an overload type fault, said electrical protection equipment is characterized in that: - the protection trigger (6) is configured to be supplied with voltage independently of the network voltage by the energy coming from said current transformer (1) further configured to transform the current flowing on the phase current line (L) into voltage, - the protection trigger 6 comprises at least one thermal memory stage (9) and a trigger stage (10) comprising said control member (8), the memory stage thermal (9) being electrically connected upstream of the trigger stage (10) and being configured to delay the power supply of the trigger stage (10) at least according to a heating time constant representative of the heating of a thermal detection bimetallic strip and at least according to a cooling time constant representative of the cooling of the thermal detection bimetallic strip.

2. Electrical protection apparatus according to claim 1, characterized in that the thermal memory stage (9) comprises at least one RC type circuit, comprising at least a first resistor (R4) in series with a first capacitor (C3) and a second resistor (R5) in parallel with the first capacitor (C3), the response times of which correspond respectively to the heating time constant and the cooling time constant.

3. Electrical protection apparatus according to any one of claims 1 to 2, characterized in that said thermal memory stage (9) is configured to delay the supply of the trigger stage (10) at least according to a first heating time constant corresponding to the heating of the thermal detection bimetallic strip with a current value preferably less than twice the nominal current and a second heating time constant corresponding to the heating of the thermal detection bimetallic strip with a current value preferably greater than twice the nominal current, the first time constant being greater than the second time constant.

4. Electrical protection apparatus according to claim 3, characterized in that the RC type circuit further comprises a branch parallel to the first resistor (R4) comprising at least one Zener diode (D8) and a third resistor (R3) connected in series and whose characteristics correspond to the first and second heating time constants.

5. Electrical protection apparatus according to any one of claims 1 to 4, characterized in that the trigger stage (10) preferably comprises a voltage detector (12) associated with a time delay.

6. Electrical protection apparatus according to any one of the claims- indications 1 to 5, characterized in that said actuator (7) is an electromagnetic actuator (7') and is configured at least to be controlled by the control member (8) of the trigger stage (10), being controlled by an electrical control signal coming from the control member (8) at least in the event of the occurrence of an overload type fault.

7. Electrical protection apparatus according to claim (6), characterized in that the protection trip device (6) comprises a power supply stage (11) parallel to the thermal memory stage (9) and being electrically connected upstream of the tripping stage (10) and configured to store the energy coming from the first current transformer (1) and to supply the tripping stage (10) from said stored energy to control the control member (8) in the event of the occurrence of an overload type fault.

8. Electrical protection apparatus according to claim 6 or claim 7, characterized in that said control member (8) preferably comprises a power transistor of the thyristor, bipolar transistor or field effect transistor type.

9. Electrical protection apparatus according to any one of claims 6 to 8, characterized in that it further comprises a neutral current line (N) and a differential current sensor (14) crossed by the phase current line (L) and the neutral current line (N) to further measure the difference in current flowing between said phase current line (L) and the neutral current line (N) and emit an acquisition signal representative of the difference in current between the phase current line (L) and the neutral current line (N) and a differential fault detection unit (15) connected upstream of the latter to the differential current sensor (14) so ​​as to be powered independently of the network voltage and connected downstream of the latter to the electromagnetic actuator (7') to control it in the event of the occurrence of a differential fault.

10. Electrical protection apparatus according to any one of claims 1 to 5, characterized in that the control member (8) comprises at least one switch, preferably of low impedance, connected in series with said actuator (7), the switch and said actuator (7) being mounted in parallel with a magnetic detection coil (13) of the phase line (L) and in that in the event of an overload type fault the switch is configured to be switched in a on state to allow the power supply of said actuator (7) by the voltage drop coming from the magnetic detection coil (13).

11. Electrical protection apparatus according to claim 10, characterized in that the protection trigger (6) is devoid of power supply means configured to store the energy coming from the first current transformer (1).

12. Electrical protection apparatus according to claim 11, characterized in that said control member (8) comprises at least one power transistor and preferably at least one FET field effect transistor.

13. Electrical protection apparatus according to any one of claims 9 to 12, characterized in that said actuator (7) is a micro-bimetallic strip actuator (7”).

14. Electrical protection apparatus according to any one of claims 9 to 12, characterized in that said actuator (7) is an electromagnetic actuator (7').

15. Electrical protection apparatus according to claim 14, characterized in that it further comprises a neutral current line (N) and a differential current sensor (14) crossed by the phase current line (L) and the neutral current line (N) to further measure the current difference flowing between said phase current line (L) and the neutral current line (N) and emit an acquisition signal representative of the current difference between the phase current line (L) and the neutral current line (N) and a differential fault detection unit (15) connected upstream thereof to the differential current sensor (14) so ​​as to be powered independently of the network voltage and connected downstream thereof to the electromagnetic actuator (7') via said control member (8) to control the electromagnetic actuator (7') in the event of the occurrence of a differential fault.

16. Electrical protection apparatus according to any one of claims 1 to 15, characterized in that the protection trigger (6) comprises a filtration and overvoltage protection stage (16) connected upstream of the thermal memory stage (9).

17. Electrical protection apparatus according to any one of claims 1 to 16, characterized in that the protection trigger (6) comprises at least one electronic card comprising at least the thermal memory stage (9) and the trigger stage (10).

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