WO2004054061A1

WO2004054061A1 - Event time-stamping device

Info

Publication number: WO2004054061A1
Application number: PCT/FR2003/003549
Authority: WO
Inventors: Claude Bruel; Gilles Rougier; Alain Rousseau; Armand Tcheng
Original assignee: Societe D'etudes Et De Fabrication Des Techniques Industrielles Modernes
Priority date: 2002-12-03
Filing date: 2003-12-02
Publication date: 2004-06-24
Also published as: AU2003298387A1; FR2848008B1; FR2848008A1

Abstract

The invention concerns a self-contained device (1) for monitoring events in an electrical conductor (4), comprising a sensor (40) for detecting variation of a magnetic flux in an electrical circuit coil, said flux variation being generated by an event, and further comprising means (43) for counting, storing and time-stamping events and means (44, 3) for displaying and visualizing event time-stamping. The invention is characterized in that the coil is a printed circuit coil and is arranged in a housing (2) of the device adapted to be mounted directly on the conductor (4).

Description

EVENT TIMING DEVICE.

GENERAL TECHNICAL AREA. The present invention relates to autonomous devices for monitoring physical events.

More specifically, it relates to autonomous devices for monitoring and time stamping events in an electrical conductor. STATE OF THE ART. Means and devices for monitoring physical events are already known in the state of the art, making it possible, in particular, to detect and count a certain number of physical phenomena.

The physical phenomena that one seeks to observe and count are, for example, changes in the magnetic field or the electric field within a given perimeter, or also changes in the intensity of the current flowing through an electrical conductor.

The detection and the counting of these physical events can have a scientific interest of course, but also an interest for the insurance or maintenance companies for example. Indeed, some insurance companies want to ensure that certain material damage declared by their customers has been caused by an alleged physical event, and not by negligence on the part of their customer.

This is particularly the case for damage caused by lightning.

Still in this particular application given by way of example, the observation and counting of lightning strikes can also be useful for the maintenance of a certain number of devices, in particular lightning conductors or lightning arresters.

Figures 1 and 2 schematically show an example of a known device for detecting and counting lightning strikes. Such a detection and counting device 1 is mounted near an electrical conductor, generally a downward conductor of the lightning conductor type 4. It is recalled that a lightning conductor is a device for protection against atmospheric discharges comprising, in general, one or more rods or points, earth connections and down conductors bringing these elements together. The lightning rod is therefore referenced by 4 in all of the figures in this description. It extends vertically in order to be able to attract lightning at its top, which does not fall on the building on which it is placed.

The device 1 includes display and display means 3 making it possible to display the number of lightning strikes which have struck the lightning rod 4.

The device 1 is fixed to the lightning rod 4 by fixing means referenced by 5 in FIG. 1. The means 5 are for example screws fixed in a wall.

During a discharge caused by lightning touching the top of the lightning conductor 4, the electrical overcurrent moves in the down conductor of the lightning conductor 4 to the earth connection generally located on the ground. The current therefore flows in the lightning rod 4 in the direction referenced by 10 for example in FIG. 1.

The device 1 detects the overcurrent during its passage through the conductor 4. It increments a counting device, which therefore makes it possible to determine the number of lightning strikes which have struck the lightning rod 4 since the device was put into service on the lightning rod.

To this end, the device comprises a magnetic circuit 100 which is closed on itself around the conductor 4 without being in contact with the conductor 4. The magnetic circuit 100 is constituted by a core 101 on the one hand and on the other hand by the space 102 occupied by a non-magnetic material, for example air. As shown in Figure 2, the circuit 101 is generally a substantially rectangular frame.

An electrical circuit, which comprises a winding 103 having at least one turn and up to a few tens of turns, is wound around the magnetic core 101. The coil 103 and connected between two input terminals of an analog-digital converter 104 .

The analog to digital converter 104 is supplied by a supply circuit 105, and has an output terminal which is connected to a microprocessor 106 to deliver a signal representative of the lightning current in the conductor 4.

The microprocessor is also supplied by the supply circuit 105, and it is connected to a clock 107, to a memory 108, and to an interface circuit 109 comprising display means 110 and input means 111, the three circuits 107, 108 and 109 being themselves supplied by the supply 105.

It is therefore possible to time stamp the events taking place in the conductor 4. The principle diagram for detecting the passage of current in the lightning conductor 4 is shown diagrammatically in FIG. 3.

During the passage of an overcurrent represented by 30, there is creation of a magnetic field 31 in the circuit 101 winding around the overcurrent in a clockwise direction for a falling intensity. This winding is known as a "right hand theorem" by those skilled in the art. The variation in magnetic field flux is then detected through a window 32 or a detector, represented here by the winding 103 in FIG. 1. The flux variation is detected because it itself creates an induced current in the winding 103 whose intensity can be measured. By knowing the induced current, we can go back to knowing the current overcurrent, these two currents being linked by the characteristics of the conductors in the circuit.

The prior art has been more precisely described for lightning strike counters, but of course, there are also devices for detecting overcurrents in any electrical conductor, for example an overcurrent with respect to a useful signal in a communication network.

Other events can also be detected, such as variations in the magnetic or electric field using techniques known to those skilled in the art.

The devices of the prior art do not however bring total satisfaction. It is noted that despite their practical interest, the monitoring devices described above have not experienced the expected industrial development.

One of the reasons for this is that the devices of the prior art require the presence of a magnetic circuit surrounding the conductor 4 for the detection of events in the conductor 4. The magnetic circuit is generally bulky, and is not easily integrated in a case. The mounting of the devices according to the invention near the conductor 4 is therefore not easy. In addition, the means 3 of the devices of the prior art are often complicated and require the actuation of several input devices for displaying the measurements.

Finally, the devices of the prior art do not allow the electrical charge of the event to be traced. PRESENTATION OF THE INVENTION.

The invention proposes to improve the situation and to propose a device having advantages over the prior art.

One of the aims of the invention is therefore to propose a practical device for detecting events in an electrical conductor which can also provide a time stamp of the event.

One of the aims of the invention is therefore in particular to propose a device for detecting events in an electrical conductor which can be easily and directly mounted on the conductor.

One of the aims of the invention is therefore in particular to propose a detection device in the form of a box.

One of the aims of the invention is therefore to propose a device for detecting events without the presence of a magnetic circuit.

One of the other aims of the invention is to propose an event detection device whose consultation of the measurements is also facilitated.

One of the aims of the invention is in particular to propose a device, the measurements of which can be consulted by actuating a single input device. Finally, one of the aims of the invention is to propose a device making it possible to give the load of the event.

To this end, the invention provides an autonomous device for monitoring events in an electrical conductor, comprising a sensor for variation of a magnetic field flux in a coil of an electric circuit, this variation in flux being generated by a event, and further comprising on the one hand means for counting, memorizing and time stamping of events and on the other hand means for displaying and viewing the time stamping of events, characterized in that the coil is of the printed circuit type and is arranged in a housing of the device able to be mounted directly on the conductor.

Thus, for insurance companies, to find out if the damage declared by one of their policyholders is really due to a thunderbolt, the present invention makes it possible to precisely and easily date the event to verify the declarations, and correlate the information with bulletins weather for example.

Likewise, the invention makes it possible, for maintenance procedures, to be able to date the event. Indeed, certain maintenance procedures must be carried out within a certain time following an event, such as a lightning strike.

We note that by set of events is meant a succession in time of physical events of the same nature.

The invention is advantageously supplemented by the following characteristics, taken alone or in any of their technically possible combinations:

- The sensor further comprises means making it possible to memorize the intensity of the current passing through the coil and which is a function of the intensity of the event which takes place in the conductor;

the means include integrating means making it possible to trace the load which created the current passing through the coil;

- The device comprises means able to allow a user to scroll through the set of events to view a selected event on the viewing means; the display means are capable of displaying the rank, the year, the month, the day, the hour and the minute of the occurrence of each event.

- The device includes means for sending a signal out of the housing upon the occurrence of an event; - The sending means comprise means generating a light signal and an optical fiber transporting said light signal out of the housing;

the sending means comprise means generating a radio signal to send information on at least one event outside the box; - The device includes autonomous power supply means; and

- The coil has at least two circuits forming coils connected in series.

PRESENTATION OF THE FIGURES

Other characteristics, objects and advantages of the invention will emerge from the description which follows, which is purely illustrative and not limiting, and which should be read with reference to the appended drawings in which:

- Figures 1 and 2, already discussed, schematically represent a device for detecting and counting lightning strikes according to the state of the art; - Figure 3, already discussed, schematically shows the principle of detecting an overcurrent passing through a conductor;

- Figure 4 schematically shows a possible assembly of an embodiment according to the invention;

- Figure 5 shows schematically an advantageous embodiment of a magnetic field sensor disposed in a device according to the invention;

- Figure 6 schematically shows a possible embodiment of a housing according to the invention; and

- Figure 7 shows schematically all the blocks that can be arranged in a housing of a device according to the invention. DETAILED DESCRIPTION.

FIG. 6 schematically represents a possible embodiment of a device 1 for detecting, counting and time stamping physical events according to the invention. FIG. 6 shows that the device 1 mainly comprises a housing 2 able to be mounted on an electrical conductor, generally a downward conductor of lightning conductor 4, the housing preferably being of substantially parallelepipedal shape comprising on a front face 11 of vertical extension of the means 3 for displaying and viewing information relating to the detection, counting or time stamping of physical events. The means 3 comprise for example a liquid crystal screen.

During a discharge caused by lightning touching the top of the lightning conductor 4, the electrical overcurrent moves in the down conductor of the lightning conductor 4 to the earth connection generally located on the ground. The current therefore flows through the lightning rod 4.

A rear face 12 which extends vertically and is opposite to the front face 11 comprises means for fixing to an electrical conductor 4.

The fixing means are referenced by 5 in FIG. 7, which is a schematic longitudinal section of the device 1 and of the functional blocks located inside the housing 2. The fixing means 5 comprise a flange plate and fixing means 20 of the flange on the rear wall of the housing, comprising for example screws.

Thus, when the housing 2 is in position on the lightning rod 4, the latter extends between the wall 12 of the housing 2 and the plate of the means 5. The wall 12 and the plate are substantially parallel with respect to the other.

The fixing means 5 make it possible to fix the device 1 to the conductor 4 in an insulating manner. They thus guarantee the autonomy of the system.

“Autonomy” is understood to mean autonomy both in supplying power to the various components constituting the device 1, and autonomy in the potential of the device 1. In fact, the device 1 is not connected to any external conductor. It is not part of any electrical circuit. This is why it can be mounted, thanks to an insulating connection, on lightning conductors 4 which are crossed by very large electrical currents. The device 1 is electrically isolated from the outside world and is not likely to be crossed by a strong current which could damage it or damage elements of a circuit in which it would be mounted. FIG. 7 thus shows that the housing 2 comprises, near the rear wall 12 of the housing 2 and of the conductor 4, a block 40 for detecting a physical phenomenon.

The detection block 40 is located near the rear wall of the housing 2 and near the conductor 4, in order to ensure better detection of the event. Block 40 detects the event and transforms it into an electrical signal.

The output of block 40 is connected to means 41 for processing the electrical signal from sensor 40, in order to be able to inject the signal into a comparator block 42 which compares the value of the electrical signal with a predetermined threshold depending on the chosen application.

If the signal value is greater than the threshold, then a counter block 43 is triggered which increments the number of events which have occurred in the conductor 4, and according to the invention also triggers a time stamping of the event which has just happen. The detection, counting and time stamping information is then sent to the display means 44 and the screen 3 on the front face 11 of the housing 2.

Thus, the device 1 comprises means making it possible to detect, count and time stamp physical events, such as a variation of a magnetic field, of an electric field, or to detect an overcurrent crossing the conductor 4.

The following description takes as an example the detection of an overcurrent. This overcurrent can take place on a lightning rod, on a lightning arrester protecting an electrical installation, a conventional electrical installation, or conductors of telecommunication networks transporting an electrical signal carrying information. Thus the conductor 4 can be of different nature depending on the applications. The components of the different blocks of device 1 are such that device 1 can meet the UTE C 17-106 standard. In particular, the standard defines that the orders of magnitude of the detected overcurrents are 1 kA. Thus, the device 1 detects an overcurrent with respect to a threshold, the threshold being fixed and predetermined in means 42 visible in FIG. 7.

FIG. 4 schematically represents an electronic circuit allowing a possible embodiment of the device according to the invention. The circuit of FIG. 4 uses the “surface-mounted circuit” or CMS technology according to the terminology generally used by those skilled in the art. The CMS technology makes it possible to obtain a very flat circuit and obtain a compact housing.

It is thus noted that the block 40 mainly comprises a coil making it possible to detect the variation in the flux of the magnetic field created by the overcurrent 30 passing through the conductor 4.

FIG. 5 shows that the detector unit 40 advantageously comprises a winding forming a coil materialized in the form of a printed circuit technology.

The detector is arranged in an eccentric position relative to the axis of the conductor 4. Such a position avoids the compensation of the fluxes entering and leaving the coil, compensation which occurs if the detector is centered relative to the axis of the connector 4.

Advantageously and as shown in FIG. 5, the sensitivity of the block 40 is increased by mounting in series at least two coils 61 and 62 of the same type and offset relative to the axis 30. The two coils 61 and 62 are mounted in series , but the direction of winding of the coils of each coil is symmetrical to that of the other coil with respect to a plane passing through the axis 30 and perpendicular to the plane passing through the coils 61 and 62. A coil has its coils s 'winding clockwise, the coil mounted in series has its windings winding counterclockwise. Thus, the magnetic field fluxes do not compensate for each other. The entire block 40 can therefore be centered on the axis 30. Advantageously, the circuit comprises four coils mounted in series and whose winding directions are symmetrical with respect to the axis. The circuit then comprises two coils on each surface of the plate on which it is mounted. The block 41 mounted at the outlet of the block 40 mainly comprises a diode bridge making it possible to rectify the signal, and thus detect an overcurrent whatever its direction of passage in the conductor 4.

The circuit of FIG. 4 also includes a block 55 intensity limiter leaving the block 40. It is on the one hand connected to the outlet of the block 40 and on the other hand connected to the inlet of the block 41. It thus protects the entire circuit downstream of it.

Block 41 therefore processes the signal in order to be able to inject it into block 42 which mainly comprises a capacitor C1, the charge and discharge of which are measured in a resistor R3. The block 42 also includes a Zener diode D1 mounted in parallel with the resistor R3 and which performs the function of clipping the electrical signal originating from the charging and discharging of the capacitor C1.

The output of the diode D1 is connected to elements forming logic gates 56, 57 forming comparator at a predetermined threshold. Thus, as a function of the signal level at the output of block 41, the logic elements 56 and 57 provide an instruction to an assembly 58 forming an integrated circuit forming a counter and a time stamp, in particular having moreover an integrated clock which makes it possible to time stamp each event.

If the signal at the output of block 41 is less than the threshold, then the assembly 58 does not count any additional event.

If, on the other hand, the threshold is exceeded, the logic elements 56 and 57 deliver to the assembly 58 a signal capable of incrementing an event counter.

The information recorded by all of the integrated circuits 58 is then transferred to the display block 44. The block 44 transmits to the screen 3 located on the wall of the housing 2 for its display for a user.

The display includes information concerning the rank 50 of the event in the set of detected events, information 51 concerning the year of the event, information 52 concerning the month of the event, information 53 concerning its day, as well as the hour and minutes in 54 at which it occurred.

The set 58 of integrated circuits can detect x events and display one by one y events. X and y can be equal, but can for example be equal to 100 and 10 respectively.

FIG. 6 shows that the scrolling of the information on the display means 3, in particular the display of the events y according to their rank, is carried out by means 6 fixed on a wall of the housing 2. The means 6 allow a user to scroll through the events recorded on the display and include, for example, a press button. Advantageously, the press button is fixed under the lower wall of the housing 2 so as not to be sensitive to bad weather.

Advantageously, the device 1 comprises means allowing the adjustment of the time stamping means included in the assembly 58. In particular, the adjustment means comprise means for setting the time of the internal clock and the date counted by l 'set 58. The adjustment means can be combined with the means 6 for scrolling events, or have a separate push button fixed to a wall of the housing 2. As a variant, it can be a magnetic actuator which acts through the housing, for controlling a Reed type bulb for example. The protocol for adjusting the time stamping means is conventional and is carried out, for example, by pressing on the adjustment means. In a variant, it is also possible to provide devices allowing synchronization of the time stamping means with respect to a high precision clock, by radio electric means for example. Thus, the device always remains on time and a very high time stamping precision is obtained, without a user needing to reset the device after a clock drift over time. Advantageously, resetting the event counter to zero is impossible by a user, and can only be carried out by returning to the factory and dismantling the device. This avoids abuse by malicious people, who would not have carried out actions of maintenance after an event for example, and who would like to erase the traces of this omission.

Advantageously also, the box 2 can comprise means making it possible to send a signal out of the box 2 during the occurrence of an event.

This signal makes it possible to warn an outside person during the occurrence of an event, for example with a view to maintenance in a time relatively close to the event.

The sending means comprise for example means sending a radio signal. Preferably, the sending means comprise a light generator and an optical fiber 7 sending a light signal out of the housing 2 to warn a person, or trigger a device remotely.

This device 7 for sending the signal out of the housing 2 is preferably in optical form, in order to maintain the characteristic of autonomy of potential and isolation of the device 1 vis-à-vis the outside world.

The box can also include radio link means with a module carried by a user. Thus, the user can consult the measurements made by the device remotely, or the box can send the measurement results or an alarm signal remotely, while maintaining the autonomy of the box.

It should be remembered that autonomy means an autonomy of electric supply as well as an autonomy of electrical potential, that is to say that the device 1 is not connected to anything electrically and can undergo phenomena or events. high electrical amplitude without damaging a circuit or installation located downstream for example.

Conventionally, to ensure the autonomy of the power supply to the device, it comprises a conventional long-life battery. However, it is possible in a variant to provide means 8 forming a solar cell visible in FIG. 6.

The dimensions of the parallelepiped housing are of the order of 5 cm. The housing is waterproof to withstand the most difficult atmospheric conditions.

According to an advantageous variant, represented diagrammatically in FIG. 7, the device further comprises a block 45 making it possible to store information which is a function of the intensity of the event 30 which takes place in the conductor 4.

In the example of the present description, it may be the current measured at the output of the detector 40. Thus, knowing the values of the inductances and the mutual between the conductor and the coil, we can go back to the intensity of the current which passed through the conductor 4. One can also, by integrating this value of the current, go up to the load which created this current.

Advantageously, this information on the intensity of the event which has occurred in the conductor 4 is transmitted to the display and display means 44 to be displayed on the display screen 3 of the box 2.

Thus, the housing 2 comprises two main circuits mounted in parallel from the output of the sensor 40. The first circuit is composed of the block (41, 42 and 43) and possibly includes a clipping step at the output of the sensor 40 in order to compare a pulse to a predetermined threshold, for counting and time stamping. The second circuit mainly comprises the block 45 which stores in memory an analog information at the output of the detector 40 which can be linked thereafter to the value of the intensity of the event.

Claims

CLAIMS.

1. Autonomous device (1) for monitoring events in an electrical conductor (4), comprising a sensor (40) for variation of a magnetic field flux in a coil of an electric circuit, this variation in flux being generated by an event, and further comprising on the one hand means (43) for counting, memorizing and time stamping of events and on the other hand means (44, 3) for displaying and displaying the time stamp events, characterized in that the coil is of the printed circuit type and is arranged in a housing (2) of the device able to be mounted directly on the conductor (4).

2. Device according to claim 1, characterized in that the sensor (40) further comprises means (45) for memorizing the intensity of the current passing through the coil and which is a function of the intensity of the event which takes place in the conductor.

3. Device according to claim 2, characterized in that the means (45) comprise integrating means making it possible to go back to the load which created the current passing through the coil.

4. Device according to one of claims 1 to 3, characterized in that it comprises means (6) able to allow a user to scroll through the set of events to view an event chosen on the viewing means (3).

5. Device according to one of claims 1 to 4, characterized in that the display means (3) are capable of displaying the row (50), the year (51), the month (52), the day ( 53), the hour and minute (54) of the occurrence of each event.

6. Device according to one of claims 1 to 5, characterized in that it comprises means making it possible to send a signal out of the housing during the occurrence of an event.

7. Device according to claim 6, characterized in that the sending means comprise means generating a light signal and an optical fiber (7) transporting said light signal out of the housing (2).

8. Device according to claim 6, characterized in that the sending means comprise means generating a radio signal to send information on at least one event outside the housing (2).

9. Device according to one of claims 1 to 8, characterized in that it comprises autonomous electrical supply means.

10. Device according to one of claims 1 to 9, characterized in that the coil comprises at least two circuits forming coils (61, 62) connected in series.