AU2019447727B2

AU2019447727B2 - Electric line (L) protection device for detecting a leakage fault, a short-circuit, fault, an overcurrent fault and an arc fault

Info

Publication number: AU2019447727B2
Application number: AU2019447727A
Authority: AU
Inventors: Nicolas CALMELET; Jean Giordano; Denis MERAND
Original assignee: Hager Electro SAS
Current assignee: Hager Electro SAS
Priority date: 2019-05-29
Filing date: 2019-05-29
Publication date: 2022-12-08
Anticipated expiration: 2039-05-29
Also published as: CN114207972B; EP3977577A1; WO2020240097A1; AU2019447727A1; EP3977577B1; CN114207972A

Abstract

The present invention relates to an electric line protection device (L), the device comprising, in a housing that it comprises, on the one hand, a plurality of coils (1, 2, 3) and a movable actuating element configured to be moved, under the effect of a magnetic field, from a rest position to an actuation position, namely a first coil (1) forming an actuator able and intended to generate the magnetic field in response to a differential fault occurring in the line (L), a second coil (2) able and intended to generate the magnetic field in response to a circuit breaker fault occurring in the line (L) and a third coil (3) and, on the other hand, a trip lock (4) and a control unit (5). An electric current proportional to that passing through the second coil (1) passes through the third coil (3), which forms a sensor for measuring the proportional current. The device further comprises an electronic processing unit (6) operatively connected to the third coil (3) and configured to control, via the control unit (5), the first coil (1) according to the result of the processing of the signals representing the measurement value of the proportional current.

Description

ELECTRIC LINE (L) PROTECTION DEVICE FOR DETECTING A LEAKAGE FAULT, A SHORT CIRCUIT FAULT, AN OVERCURRENT FAULT AND AN ARC FAULT

Field of the Invention

[0001]The present invention relates to the field of electric current line protection devices. Its subject is an electric line protection device.

Background of the Invention

[0002] Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.

[0003] Electric line protection devices, in particular differential circuit breakers, are provided to protect the electric line and/or people against electrical faults occurring in said line such as leakage currents, short circuits, overloads or else electric arcs.

[0004] To this end, these protection devices are configured to trip under quite particular conditions, when there occurs:

- an imbalance between the sum of the currents entering and the sum of the currents leaving the line that is protected by such a device, this corresponding to what is referred to as "differential" protection, against leakage currents, and/or

- when the strength of the current is abnormally high, this corresponding to what is referred to as "magnetic" protection, against short circuits, and/or

- when too great an amount of current is flowing through the electric conductor in question, this corresponding to protection against prolonged low-amplitude overcurrents or overloads.

[0005] The differential protection function and the function of protection against short circuits are generally performed by coils surrounding a movable magnetic core that is able to move, under the effect of a magnetic field that is created by said coils, from a rest position to an actuation position allowing a trip lock to be actuated. More specifically, the differential protection function is generally performed by a detection circuit for detecting the differential fault occurring in the line to be protected and by a first coil forming an actuator generating, in response to said detected differential fault, a magnetic field having the effect of moving said core. The function of protection against a short circuit is generally performed by a second coil that is able to detect a short circuit in the line and to generate a magnetic field in response to a short-circuit fault that is detected on the line to be protected.

[0006] The function of protection against overloads is generally performed by virtue of a two-strip system comprising two metal strips, with different coefficients of expansion, which expand under the effect of heat following a prolonged increase of the current and which, when deformed, come to bear on a contact actuating the interruption of the current in the line.

[0007]Other protection functions such as protection against electric arcs are also performed by these protection devices, alone or in combination with at least one of the aforementioned protection functions in order to allow a greater level of protection by the protection device. An electric-arc detector is also known under the name AFDD (arc-fault detection device) and generally comprises an integrated mechanism or is associated with a device, such as a differential circuit breaker, comprising a mechanism that is described below allowing the device to be tripped so as to open the circuit or the line downstream when an electric-arc fault is detected.

[0008] Tripping the protection device following a fault of the aforementioned type in the electric current line causes the interruption of the current in said electric line. Such an interruption is produced by a mechanism, which is known under the name of trip lock, comprising movable electrical contacts and fixed electrical contacts that are configured to adopt a first position in which the fixed contact and the movable contact make electrical contact with each other, and a second position in which they are distanced from each other. In an electric line to be protected comprising a phase line and a neutral line, the trip lock generally comprises a pair of contacts, one fixed and one movable, for the phase line and a pair of contacts, one fixed and one movable, for the neutral line. Opening the contacts then causes the interruption of the current in the line downstream of said contacts, that is to say toward and in the one or more loads that are present in said line to be protected.

[0009] Such devices, according to the one or more types of protection provided, are generally known under the names of circuit breaker or switch.

[0010]However, a number of problems arise with such protection devices. A first problem is the heating caused by the two-strip system and a second problem is the bulk resulting from the set of mechanisms providing these various types of protection and with which these devices are equipped.

[0011] Document FR3028662 discloses a compact solution allowing various types of protection to be provided with one and the same actuator with multiple windings comprising a coil, referred to as a differential coil, generating a magnetic field in response to a differential fault and a magnetic coil that is nested within the differential coil generating a magnetic field in response to a short-circuit fault. It further comprises a third coil that is wound in a short circuit and nested within said differential coil and magnetic coil. However, this solution does not perform other protection functions such as the detection of electric arcs (AFDD) or protection against overloads.

[0012] Solutions involving shunt sensors so as to detect an overload do not solve the heating problems.

[0013] Solutions using Rogowski or torus sensors are large and do not solve the bulk problem. Furthermore, these solutions make it difficult to add a function of protection against electric-arc faults, in particular for ratings up to 45 A, without modifying the size of the protection device.

Summary of the Invention

[0014] The aim of embodiments of the present invention is to overcome these drawbacks by providing an electric line protection device allowing a plurality of types of protection to be provided, and more particularly at least protection against short circuits, leakage currents and overloads, while at the same time reducing the bulk of the device.

[0015] To this end, an embodiment of the present invention is an electric line protection device, said device comprising, in a housing that it comprises, on the one hand, a plurality of coils and a movable actuation element that is configured to be moved, under the effect of a magnetic field, from a rest position to an actuation position, namely a first coil forming an actuator that is able and intended to generate said magnetic field in response to a differential fault occurring in said line, a second coil that is able and intended to generate said magnetic field in response to a short circuit fault occurring in said line and a third coil and, on the other hand, a trip lock that is able and intended, when actuated under the effect of the movement of said movable actuation element, to transition from a first state to a second state, a control unit that is able and intended, following the detection of a differential fault, to control the first coil so as to generate said magnetic field and a detection circuit for detecting said differential fault that is functionally connected to the control unit and being essentially characterized in that the third coil is able and intended to have an electric current flow through it that is proportional to the electric current flowing through said second coil and in that it comprises an electronic processing unit that is functionally connected to said third coil and configured to process the signals that are representative of the value of the strength of said proportional electric current so as to determine, by comparing said value with at least one predetermined threshold value, whether at least one trip threshold has been exceeded and, if so, to control, via the control unit, the first coil generating said magnetic field.

[0016] Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

[0017] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

Brief Description of the Drawings

[0018]The invention will be better understood by virtue of the following description, which relates to one preferred embodiment that is given by way of non-limiting example and explained with reference to the appended schematic drawings, in which:

[0019]The figure shows a block diagram of the electric line protection device according to the present invention in the state of being electrically connected to said electric line to be protected between the phase and the neutral thereof and upstream of a load that is present on said line.

Detailed Description

[0020] The figure depicts an electric line L protection device, said device comprising, in a housing that it comprises:

- a plurality of coils 1, 2, 3 and a movable actuation element (not shown in the appended figure) that is configured to be moved, under the effect of a magnetic field, from a rest position to an actuation position, namely a first coil 1 forming an actuator that is able and intended to generate said magnetic field in response to a differential fault occurring in said line L, a second coil 2 that is able and intended to generate said magnetic field in response to a short-circuit fault occurring in said line L and a third coil 3,

- a trip lock 4 that is able and intended, when actuated under the effect of the movement of said movable actuation element, to transition from a first state to a second state,

- a control unit 5 that is able and intended, following the detection of a differential fault, to control the first coil 1 so as to generate said magnetic field, and

- a detection circuit 8 for detecting said differential fault that is functionally connected to the control unit 5.

[0021] The third coil 3 is able and intended to have an electric current flowing through it that is proportional to the electric current flowing through said second coil 2. The third coil 3 thus forms a current-measuring sensor making it possible to measure said proportional current that is induced in said third coil 3 in association with the electronic processing unit 6 that is mentioned below.

[0022] Such a protection device further comprises an electronic processing unit 6 that is functionally connected to said third coil 3 and configured to process the signals that are representative of the value of the strength of said proportional electric current so as to determine, by comparing said value with at least one predetermined threshold value, whether at least one trip threshold has been exceeded and, if so, to control, via the control unit 5, the first coil 1 generating said magnetic field. It is understood that said magnetic field has the effect of moving the movable actuation element that then actuates the trip lock 4 by making it transition into the second state.

[0023]The second state corresponds to a state where the flow of the electric current is interrupted downstream in the line L to be protected, that is to say in the portion of the line that is affected by the detected fault.

[0024] The sole figure depicts the three coils 1, 2 and 3 separately, but in reality, in a preferable embodiment, the first coil 1 and the second coil 2 may surround the movable actuation element and said first and second coils 1 and 2 may be nested within each other. Preferably, the third coil 3 may be nested within said first and second coils 1 and 2. It will be understood that the third coil 3 may not be nested within the two other coils 1 and 2.

[0025] The third coil 3, which is associated with the electronic processing unit 6, may thus deliver a voltage that is proportional to the current of the load C that is present in the electric line L to be protected.

[0026] The third coil 3 thus offers the advantage of not being connected directly to the potential which the protection device is connected to in the electric line L to be protected but of being isolated from said potential, operating like an electric transformer.

[0027] Preferably, the inductance of the first coil 1 may be of the order of a few mH. The inductance of the second coil 2 may be of the order of a few pH. The inductance of the third coil 3 may be of the order of a few mH.

[0028] The figure depicts more particularly that the first coil 1 and the second coil 2 are able and intended to be connected, in the state of being connected in the electric line L to be protected as shown in said figure, between the phase PH and the neutral N and more particularly in parallel.

[0029] Further, it may be seen in the figure that the protection device is arranged, that is to say connected in the electric line L, upstream of a load C that is present in said line. More particularly, it may be seen that two pairs of contacts 4a, 4b are arranged, one on the phase PH and the other on the neutral N, upstream of the load C so as, when they are activated in the closed state, that is to say in the second state of the trip lock 4, to interrupt the flow of the electric current downstream of said contacts, more particularly through a load C in order to protect said load or the person in contact with said load according to the type of detected fault.

[0030] The trip lock 4 may further comprise a maneuvering member, which is not shown, taking the form, for example, of a lever, which is functionally connected to the trip lock 4, and may project from a face of the housing, so as to allow the trip lock 4 to be actuated manually. The contacts 4a, 4b of the trip lock 4 may comprise movable contacts 4b and fixed contacts 4a. The trip lock 4 may then be configured to switch from a first position, corresponding to the closed state, in which position the fixed contacts 4a make contact with the respective movable contacts 4b and, as is shown in the figure, to a second position, corresponding to the open state, in which position the fixed contacts 4a are distanced from the movable contacts 4b.

[0031]The control unit 5 may consist of a control member such as, for example, a thyristor that may be connected to the electronic processing unit 6 so as to be able to be activated by said unit when the or one of the trip thresholds is reached or exceeded and be connected to the first coil 1. The control member 5 may further be connected to the terminals of a DC voltage Vcc source 7. The control member 5 may then be able and intended to control or drive the first coil 1 when said control member is activated by the electronic processing unit 6, that is to say that said control of the first coil 1 has the effect that said coil has an electric current flowing through it that is liable to generate, or to create, the magnetic field allowing the movable actuation element actuating the contacts 4a, 4b to be moved so as to make them transition from the open state to the closed state. A protection component 9 such as a varistor may be provided to protect the thyristor in the event of overvoltage.

[0032]As may be seen in the figure, the electronic processing unit 6 may comprise an electronic processing circuit 6c, such as a microcontroller or a processor, which may be configured to process said signals that are representative of the value of the strength of said proportional electric current and to control, via the control unit 5, the first coil 1 generating said magnetic field.

[0033] Preferably, the electronic processing unit 6 may further comprise an amplification circuit 6a that is connected to the third coil 3 and a filtering circuit 6b that is connected to said amplification circuit 6a. The electronic processing circuit 6c, such as for example the microcontroller or the processor, may then be connected to said filtering circuit 6b on the one hand and to the control unit 5 on the other hand. The amplification circuit 6a, the filtering circuit 6b and the electronic processing circuit 6c may preferably be connected in series.

[0034]The electronic processing unit 6, more particularly where applicable the electronic processing circuit 6c such as the microcontroller or the processor, may be configured to perform, on the basis of the processing of the signals that are representative of the value of the strength of the proportional electric current flowing through said third coil 3, at least one of the following measurement and/or detection functions:

- measuring energy in terms of current and/or voltage,

- detecting electric arcs,

- measuring overvoltage and/or undervoltage.

[0035] The electronic processing unit 6 may further be configured to determine, on the basis of the processing of the signals that are representative of the value of the strength of the proportional electric current flowing through said third coil 3, data that relate to the consumption of the electric current.

[0036]The electronic processing unit 6 may further comprise a communication unit allowing data to be transmitted that relate to the values that are measured by the third coil 3 and/or to the consumption of electric current, and/or to receive data allowing the operation of the electronic processing unit 6 to be configured remotely, for example so as to modify its parameters such as the one or more predetermined threshold values.

[0037]On the other hand, as may be seen in the appended figure, in one preferable embodiment of the detection circuit 8, said circuit may comprise, on the one hand, a differential-fault detector 8a, such as for example a torus, and, on the other hand, the electronic processing circuit 6c that may then be further configured to process the electrical signal that is representative of the differential fault and generated by said detector 8a with a view to determining whether said differential fault is present on the line L to be protected and to activate, following said detection, the control unit 5 for the first coil 1. The detector 8a, such as the torus that is shown in the appended figure, may be functionally arranged in the line L downstream of the trip lock 4 and upstream of the load C that is present in the line L to be protected.

[0038] Preferably, the electronic processing circuit 6c may be functionally connected to the detector 8a, such as the torus, via an operational amplifier 8b that the detection circuit 8, preferably, may further comprise.

[0039 In another embodiment, which is not shown, where the detector 8a may be functionally connected to an electronic processing circuit that is distinct from the electronic processing circuit 6c that is connected to the third coil 3. However, the embodiment that is shown in the appended figure, in which the detector 8a is connected to the electronic processing unit 6c that is connected to the third coil 3, allows the cost price to be decreased and the bulk of the protection device to be reduced.

[0040] The inductance values of each coil 1, 2 or 3 are specific and may be determined with a view to conferring optimal operation of each function on the protection device, for example power supply, measurement and tripping the trip lock 4.

[0041 It may also be seen in the figure that the electronic processing unit 6 may comprise an electronic protection component 6d such as a Zener diode or a Transil diode that is connected in parallel with the third coil 3. Such a protection component 6d allows the circuits to be protected, in particular in the event of overvoltage or strong pulses. The Transil diode may be a unidirectional diode or, preferably, as may be seen in the figure, a bidirectional Transil diode, that is to say equivalent to two opposing Zener diodes that are connected in series.

[0042]Thus, such a protection device allows a product to be offered that is provided with a multitude of protection functions while at the same time avoiding heating through the presence of the association of the third coil 3 and of the electronic processing unit 6 and benefiting from great compactness through the nesting of the two coils 1 and 2, where applicable through the nesting of the three coils 1, 2 and 3.

[0043] Of course, the invention is not limited to the embodiment that is described and shown in the appended drawings. Modifications remain possible, in particular from the point of view of the composition of the various elements or by substituting technical equivalents, without in so doing departing from the scope of protection of the invention.

Claims

Claims

[Claim 1] An electric line protection device, said device comprising, in a housing that it comprises, on the one hand, a plurality of coils and a movable actuation element that is configured to be moved, under the effect of a magnetic field, from a rest position to an actuation position, namely a first coil forming an actuator that is able and intended to generate said magnetic field in response to a differential fault occurring in said line, a second coil that is able and intended to generate said magnetic field in response to a short-circuit fault occurring in said line and a third coil and, on the other hand, a trip lock that is able and intended, when actuated under the effect of the movement of said movable actuation element, to transition from a first state to a second state, a control unit that is able and intended, following the detection of a differential fault, to control the first coil so as to generate said magnetic field and a detection circuit for detecting said differential fault that is functionally connected to the control unit, wherein the third coil is able and intended to have an electric current flow through it that is proportional to the electric current flowing through said second coil and wherein the device comprises an electronic processing unit that is functionally connected to said third coil and configured to process the signals that are representative of the value of the strength of said proportional electric current so as to determine, by comparing said value with at least one predetermined threshold value, whether at least one trip threshold has been exceeded and, if so, to control, via the control unit, the first coil generating said magnetic field.
[Claim 2] The protection device as claimed in claim 1, wherein the electronic processing unit comprises an electronic processing circuit such as a microcontroller or a processor, which is configured to process said signals that are representative of the value of the strength of said proportional electric current and to control, via the control unit, the first coil generating said magnetic field.
[Claim 3] The protection device as claimed in claim 2, wherein the electronic processing unit further comprises an amplification circuit that is connected to the third coil and a filtering circuit that is connected to said amplification circuit, the electronic processing circuit being connected to said filtering circuit on the one hand and to the control unit on the other hand.
[Claim 4] The protection device as claimed in claim 2 or claim 3, wherein the detection circuit for detecting a differential fault comprises, on the one hand, a differential-fault detector, such as for example a torus, and, on the other hand, the electronic processing circuit which is further configured to process the electrical signal that is representative of the differential fault and generated by said detector with a view to determining whether said differential fault is present on the line to be protected and to activate, following said detection, the control unit for the first coil.
[Claim 5] The protection device as claimed in any one of the preceding claims 1 to 4, wherein the electronic processing unit, more particularly where applicable the electronic processing circuit such as the microcontroller or the processor, is configured to perform, on the basis of the processing of the signals that are representative of the value of the strength of the proportional electric current flowing through said third coil, at least one of the following measurement and/or detection functions: - measuring energy in terms of current and/or voltage, - detecting electric arcs, - detecting overvoltage and/or detecting undervoltage.
[Claim 6] The protection device as claimed in any one of the preceding claims 1 to 5, wherein the electronic processing unit is further configured to determine, on the basis of the processing of the signals that are representative of the value of the strength of the proportional electric current flowing through said third coil, data that relate to the consumption of the electric current.
[Claim 7] The protection device as claimed in any one of the preceding claims 1 to 6, wherein the electronic processing unit further comprises a communication unit allowing data to be transmitted that relate to the values that are measured by the third coil and/or where applicable to the consumption of electric current, and/or to receive data allowing the operation of the electronic processing unit to be configured remotely so as to modify its parameters such as the one or more predetermined threshold values.
[Claim 8] The protection device as claimed in any one of the preceding claims 1 to 7, further comprising an electronic protection component, such as a Zener diode or a Transil diode, which is connected in parallel with the third coil.
[Claim 9] The protection device as claimed in any one of the preceding claims 1 to 8wherein the first coil and the second coil surround the movable actuation element and in that said first and second coils are nested within each other.
[Claim 10] The protection device as claimed in claim 9, wherein the third coil is nested within said first and second coils.