AU2017264722B2

AU2017264722B2 - Differential protecting device incorporating a means for isolating a relay or analogous

Info

Publication number: AU2017264722B2
Application number: AU2017264722A
Authority: AU
Inventors: Hichem Chetouani
Original assignee: Hager Electro SAS
Current assignee: Hager Electro SAS
Priority date: 2016-05-13
Filing date: 2017-05-09
Publication date: 2021-03-18
Anticipated expiration: 2037-05-09
Also published as: FR3051293A1; AU2017264722A1; CN109075562B; WO2017194867A1; CN109075562A; EP3300540B1; FR3051293B1; EP3300540A1

Abstract

The subject of the present invention is a differential protecting device that makes it possible to detect a fault current in an electrical apparatus, with a set of functional means (3, 3', 3", 3''') for measuring, processing, evaluating and controlling and a breaking means (4) that in particular has a characteristic braking power, that is connected to the output of said functional set (3, 3', 3", 3''') and that is intended to be triggered by the control signal, this device (1) being characterised in that it furthermore incorporates a least one selective isolating means (6) that is able and intended to electrically isolate said breaking means (4), at least with respect to said functional set (3, 3', 3", 3'''), selectively.

Description

Differential protecting device incorporating a means for isolating a relay or analogous

The present invention relates to equipment and systems for the safety of goods and persons in the electrical field, more particularly the devices for the protection of persons with residual current (or RCD), and relates to a differential protection device incorporating an isolation means of the relay or the like.

This type of protection device is commonly integrated in domestic or tertiary electrical installations, upstream or at the entrance of the various trees of the power supply circuits in place, or closer to the receivers to which they are respectively affected.

Typically, these electrical installations are supplied by an alternating electric network, and protection devices of the aforementioned type are intended primarily to ensure the safety of people by detecting as soon as possible any possible leak to the earth in one of the circuits or receivers to protect. Such leaks are caused for example by direct contact of subjects with a non-insulated conductor or indirect contacts due to earth faults. These electrical incidents are likely to generate accidents, sometimes fatal, damage to equipment, fire starts, localised or generalised malfunctions or the like.

Differential protection, in the aforementioned context, is done in most cases in a fairly standardised way: the conductors of the circuit to be protected, or the conductors of the supply line of this circuit, pass in a toroid of ferromagnetic material of a transformer whose aforementioned conductors form the primary and which comprises one or more winding(s) or secondary winding(s). The toroid plays the role of a magnetic flux concentrator. Thus, in the event of a leak, resulting in an imbalance of the input and output currents in the conductors of the lines to be protected, the flux created in the toroid by this imbalance at the primary level, induces a voltage in the secondary winding, this last being used to control directly, or through dedicated electronics (signal processing stages), a breaking or opening member, in particular an actuator (for example of the relay type). The latter in turn operates an associated mechanism of trigger, breaking or opening, or those of other protection devices of the installation.

Figure 1 schematically illustrates a differential protection device with a set of electro-technical and electronic functional means providing the differential measurement and control functions and a means of breaking or opening in the form of an electromagnetic relay connected to the output of the aforementioned set.

These devices or electrical devices for differential protection may have variable characteristics. Thus, they are differentiable and characterised by their own sensitivity, which depends in particular on the type of electrical installation in which they are used and that they are intended to protect. In addition, some of these devices are only capable of detecting leaks for alternating currents (type AC) while others, which are more complete, offer solutions that are also applicable to pulsed DC (types A and F) and smoothed (type B).

The devices referred to in the context of the present application relate more particularly to those known as " voltage independent" (not depending on the presence of a supply voltage) and with a delayed or timed measuring function.

An essential and critical parameter of this type of device is the power threshold of the breaking or opening member, in particular in differential devices comprising electronic-assisted measuring technology, relying on the load of a capacitor for perform the selective tripping of said member (see Figure 1 as an example).

Currently, said breaking or opening member is subjected, very early in the manufacturing process of the final device, to a pre-adjustment of its power of opening or breaking. In addition, at its trigger chain, the means involved in the control of said member are dimensioned with a margin sufficient to ensure its operation in a specified operating range, throughout its lifetime.

The current way of proceeding, which consists in setting up a pre-adjusted relay in the product (operational differential device integrating the relay) before the final control of said product, is practical but has limitations.

Indeed, one of the problems faced by designers and manufacturers of this type of products and differential devices is that of their optimisation in terms of compactness and cost.

However, the current way of proceeding cannot lead to such an optimisation because it requires, in order to be viable and to provide a sufficient level of guarantee of triggering, an oversizing of the component (s) storing the energy, in order to be able to provide power to the opening relay significantly greater than the pre-adjusted opening power value. This significant constructive safety margin is mandatory to absorb the effects of potential different sources of variability and drift of this pre-adjusted opening power.

More precisely, between the pre-adjustment operation of the breaking or opening member and its definitive placement in the housing of the differential protection device, numerous potential causes likely to cause a drift of its opening power may appear.

Figure 2 schematically and synthetically illustrates the main factors and possible causes of variability or drift in the value of the triggering power of the opening or breaking means, between its setting during the pre-adjustment and the final control of the product, after integration and connection of said means in the protection device.

Furthermore, during the final check and taking into account the environment of mounting and connection of said means in the device, it is currently not possible to guarantee that the opening power of said means has not varied, to determine the amount of drift, if any, nor let alone to ensure that it will operate within its required operating range.

S Indeed, the control equipment or device is connected to the terminals of the breaking or opening means to be tested (as shown in Figure 3 for a device of the type represented in Figure 1) and delivers a measuring current to determine, check and possibly allow to adjust the triggering power of said means.

However, in view of its connection to the differential measurement and control functional set, only part of the measuring current (denoted ">>>" in Figure 3) is actually delivered to the breaking or opening means (the current passing through said means is noted ">" in Figure 3), a leakage current being derived and flowing through the functional set or at least some of its components (leakage current noted ">>" in Figure 3).

Object of the Invention 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.

Summary It is an objective to overcome at least the main limitations mentioned above and to make possible an effective and precise control / adjustment of a breaking or opening means mounted permanently in a differential protection device of the type mentioned above. In a first aspect, the present invention provides a differential protection device configured to detect a leakage current or fault in an electrical installation powered by at least two-phase conductors of a network or by at least one phase conductor and a neutral conductor of a network, said device comprising: a functional set being a set of measurement, processing, evaluation and control functional means configured to detect, by monitoring the current in primary conductor(s), a differential fault in the relevant network to generate a control signal when the value of the fault current is within a predetermined range and, an electromagnetic actuator, a relay or similar breaking or opening means, having a characteristic breaking or opening power, said breaking or opening means being connected by a circuit or signal transmission lines to an output of said functional set and intended to be triggered by the control signal, at least one means of selective isolation adapted to electrically isolate said breaking or opening means, at least with respect to said functional set selectively, wherein the means of selective isolation consists of a controllable state change component, mounted in the circuit or the electric transmission lines connecting said s functional set to the breaking or opening means, further wherein the means of selective isolation is connected in series with the breaking or opening means and consists of a normally open or closed component, controllable on opening including two means of electrical isolation of breaking or opening means, connected in series with the breaking or opening means, respectively upstream and downstream of the breaking or opening means, and each consisting of a normally open or closed component, controllable at the opening.

In another aspect, the present invention provides a method of in situ control of a breaking or opening means forming part of a differential protection device according to any one of claims 1 to 6, for setting, adjustment or verification of a triggering power threshold is value of the breaking or opening means,

the method including the steps of:

providing a control equipment or apparatus with a first circuit for controlling the breaking or opening means and a second circuit for supplying said at least one means of selective isolation, to connect the various circuits to said control apparatus at points of contact or connections of the differential protection device, then making settings or adjustments, followed by a check, to possibly repeat these operations until a satisfactory breaking or opening power value is obtained and finally disconnecting the control apparatus or equipment.

The invention will be better understood due to the following description, which relates to the preferred embodiments, given by way of non-limiting examples, and explained with reference to the appended diagrammatic drawings, in which:

Figure 4 is a schematic representation of a differential protection device according to the invention, in the form of a device as represented in Figures 1 and 3 and incorporating a selective isolation means according to an embodiment of the invention;

5a

Figure 5 is a schematic representation similar to that of Figure 4 of a device according to the invention subjected to a control/adjustment operation of the tripping power of the breaking or opening means; and,

Figure 6 is a symbolic representation of a practical embodiment of a selective isolation means forming part of the device according to the invention shown in Figures 4 and 5.

As shown in Figures 4 and 5, the invention relates to a differential protection device 1 for detecting a leakage current or fault in an electrical installation powered by at least two phase conductors 2, 2', 2" of a network or at least one phase conductor and a neutral conductor of a network.

This device 1 mainly comprises, firstly, a set of measurement, processing, evaluation and control functional means 3, 3', 3", 3"' suitable and intended to detect, by monitoring the current in the primary conductor(s), a differential fault in the relevant network and to generate a control signal if a fault current value within a predetermined range of values (by example fixed by a standard or similar regulation) and, secondly, an electromagnetic actuator, a relay or a similar breaking or opening means 4, in particular having a characteristic breaking or opening power.

This breaking or opening means 4 is connected by a circuit or transmission lines of the signal 5, 5' to the output of said set of functional means 3, 3', 3", 3" '(or functional set) and intended to be triggered by the control signal,

The set of functional means carrying out the differential measurement and controlling the opening or breaking means 4 may in particular comprise, in the embodiment of the device 1 shown in Figures 3 and 4: - a measuring toroid 3, - a stage 3'of impedance matching, filtering and protection, - a rectifying stage 3", - a control stage 3"' connected to the breaking or opening means 4.

The control stage 3" may, for example, comprise a control electronics 12 (controlling the state of a switch 13 determining the connection of the means 4), a charging capacity 12' storing the energy for triggering the means 4 and a diode structure 12" mounted in parallel on the switch 13.

According to the invention, the device 1 furthermore integrates at least one means 6, 6' suitable and intended for electrically insulating said breaking or opening means 4, at least with respect to said functional set 3, 3', 3", 3"', this selectively.

Thus, by providing at least one means 6, 6' adapted and intended to disconnect the breaking or opening means 4 of the various circuits and components (also 12 and 12') forming the set of functional means 3, 3', 3", 3"' and to isolate it from the latter, any possibility of leakage or current bypass can be eliminated and the measuring current delivered by the control device or equipment 9 corresponds to the current seen by the breaking or opening means 4.

In addition, by integrating the means of selective isolation 6, 6 'directly in the device 1, is avoided any complex electrical assembly during the control, and any use of external(s) additional(s)circuit(s) or component(s) , while also limiting the complexity of the manipulations to be performed during the control and by implementing only one equipment or apparatus 9 for this purpose, advantageously integrated as component or functional module dedicated to a control apparatus 9"' more global.

Preferably, the means 6 of selective isolation consists of a controllable state-switching component (for example no passing/passing) mounted in the circuit or the electrical transmission line(s) 5, 5' connecting said functional set 3, 3', 3", 3"' by means of breaking or opening 4.

According to an embodiment of the invention which is apparent from Figures 4 and 5, the means 6 of selective isolation is connected in series with the breaking or opening means 4 and consists of a normally-open or closed component, which can be controlled at the opening, preferably positively controllable at the opening.

According to a variant not shown of the aforementioned embodiment, and in order to complete the electrical isolation of the means 4, it can be provided that the device integrates two means 6 and 6' of electrical isolation of thebreaking or opening means 4, connected in series with the latter, respectively upstream and downstream of the latter, and each 6, 6' consisting of a normally open or closed component, controllable at the opening.

Figure 6 illustrates, as a practical embodiment, that each means 6, 6' can consist of a component or circuit normally closed, controlled at the opening and with losses or consumption quasi-nil in the state such as, for example, a field effect transistor of the NJFET type associated with a suitable resistor.

In order to facilitate the manipulations during the control operation and according to an advantageous arrangement, the circuit or signal transmission lines 5, 5', or the breaking or opening means 4 itself, comprises points or terminals 7, 7' of contact or connection located respectively upstream and downstream of the control input 4' of said breaking or opening means 4, for the connection or the temporary connection of supply lines 10, 10 ' of an equipment or apparatus 9 for controlling the operation, in particular for checking the threshold value of the opening or breaking power, of said means 4.

As shown by way of example of embodiment of Figures 4 and 5, said at least one means 6 of selective isolation is connected in series upstream or downstream, with respect to the points or contact or connection terminals 7, 7' for the removable control equipment or apparatus 9.

According to another possible feature facilitating control, the component forming the means 6 of selective isolating is equipped with or associated with points or contact or connection terminals 8, 8' for the temporary connection of supply lines 11, 11' of an equipment or apparatus 9 for controlling the means 6 of selective isolation.

To avoid being exposed to the external environment, it can be provided that the points or contact or connection terminals 7, 7', 8, 8' comprise removable protection or covering means (not shown).

The subject of the invention is also a method for the in-situ control of a breaking or opening means 4 forming part of a differential protection device 1 as described above, with a view to setting, adjusting or the verification of the triggering power threshold value of the aforementioned means 4.

This method is characterised in that it consists in providing a control equipment or apparatus 9 with a first circuit 9' of control/command of the breaking or opening means 4 and a second circuit 9 " supplying said at least one means 6, 6' of selective isolating, to connect the various circuits 9' and 9" of the control equipment 9 at the corresponding contact points or connections 7, 7', 8, 8' of the differential protection device 1, then to make possible settings or adjustments, followed by a control, to possibly repeat these operations until a satisfactory breaking or opening value is obtained and finally to disconnect the control apparatus or equipment 9.

This equipment 9 advantageously forms an integral part of a larger apparatus 9"' also including magnetisation/demagnetisation circuits of the relay 4, making it possible to make the adjustments, for example by approximation, by successive iterative cycles.

More precisely, by way of example and in relation with Figure 5, the isolation of relay 4 is first carried out (for example by application at component 6 of a DC voltage supplied by the second power supply circuit 9" integrated in the apparatus 9), then said relay 4 is supplied with a measuring current supplied by a source forming part of the control circuit 9', the analysis of this current making it possible to determine the triggering power (breaking/opening) of said relay 4. Depending on the value determined during this check, an iterative adjustment cycle of the relay 4 is performed (magnetisation/demagnetisation/control) until said power value is within the required range or corresponds substantially to an authorised value and/or optimal, ensuring proper operation of the relay 4 and the device 1 throughout their lifetime.

The invention also makes it possible to accommodate a reduced range of reserve in maximum triggerable power, because of a greater precision in the adjustment of the power of the relay. This technical improvement also leads to a more just sizing of components and of critical values and a reduction in tripping times.

The invention disclosed above thus provides an optimised solution, in the context of a differential product with a switching/opening device of the relay type and implementing an electronically assisted technology, which consists in controlling/reducing the variabilities of the relay 4 during the product manufacturing process.

To reduce the variability of the relay during manufacturing processes, the principle of the current pre-adjustment is replaced by an adjustment/control of the relay 4 before or during the final control of the differential product that integrates it. Such a method makes it possible to avoid the multiple possible sources for drifting of the characteristics of the relay 4 which can occur between the pre-adjustment of said relay and the placement of the latter in the product before the final control, as when using of the pre-adjustment technique described in the introduction.

The suppression, due to the invention, of the sources of variability allows the designers to optimise the sizing of the energy level to be stored, which allows a shortening of the tripping times and ultimately an implementation of storage means more reduced (capacity), a reduction in toroid volume and so its cost and/or performance improvement.

Of course, the invention is not limited to the embodiments described and shown in the accompanying drawings. Modifications are possible, especially 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

Claims:

1. A differential protection device configured to detect a leakage current or fault in an electrical installation powered by at least two-phase conductors of a network or by at least one phase conductor and a neutral conductor of a network, said device comprising: a functional set being a set of measurement, processing, evaluation and control functional means configured to detect, by monitoring the current in primary conductor(s), a differential fault in the relevant network to generate a control signal when the value of the fault current is within a predetermined range and, an electromagnetic actuator, a relay or similar breaking or opening means, having a characteristic breaking or opening power, said breaking or opening means being connected by a circuit or signal transmission lines to an output of said functional set and intended to be triggered by the control signal, at least one means of selective isolation adapted to electrically isolate said breaking or opening means, at least with respect to said functional set selectively, wherein the means of selective isolation consists of a controllable state change component, mounted in the circuit or the electric transmission lines connecting said functional set to the breaking or opening means, further wherein the means of selective isolation is connected in series with the breaking or opening means and consists of a normally open or closed component, controllable on opening including two means of electrical isolation of breaking or opening means, connected in series with the breaking or opening means, respectively upstream and downstream of the breaking or opening means, and each consisting of a normally open or closed component, controllable at the opening.

2. The device according to claim 1, wherein each means of selective isolation consists of a normally closed component or circuit, controlled at the opening and at losses or quasi zero consumption in the passing state, such as for example a field effect transistor NJFET type associated with a suitable resistor.

3. The device according to either of claims 1 or 2, wherein the circuit or the signal transmission lines or the breaking and opening means comprise(s) points or terminals of contact or connection located respectively upstream and downstream of the control input of said breaking or opening means, for the connection or temporary connection of supply lines of equipment or apparatus for controlling the operation, for checking the value of the opening or breaking power, of said the breaking or opening means.

4. The device according to any one of the preceding claims, wherein said at least one means of selective isolation is connected in series upstream or downstream with respect to the points or terminals of contact or connection for the removable control equipment or apparatus.

5. The device according to any one of claims 1 to 4, wherein the component forming the means of selective isolation is equipped with or associated with points or contact terminals or connection for the temporary connection of supply lines of an equipment or apparatus for controlling the means of selective isolation.

6. The device according to one of claims 4 and 5, wherein the points or contact or connection terminals comprise removable protection or covering means.

7. A method of in situ control of a breaking or opening means forming part of a differential protection device according to any one of claims 1 to 6, for setting, adjustment or verification of a triggering power threshold value of the breaking or opening means,

the method including the steps of: