FR2987897A1 - Measurement device for use in online carrier current receiver to measure current flowing in e.g. electrical conductive wire, has analysis element and/or processing element for analyzing and/or processing electrical signal at terminals - Google Patents

Abstract

The device (10) has an assembly (12) including measurement elements (13a, 13b), where each element is magnetically coupled with a medium in which current to be measured is flown. The measurement elements are connected in series and/or parallel manner. An analysis element (14) and/or processing element (15) analyze and/or process an electrical signal at terminals of the assembly. Some of the measurement elements are juxtaposed with each other in an axis of the medium. Delay elements are associated with the measurement elements.

Description

TECHNICAL FIELD The present invention relates to a device for measuring a current. The invention also relates to an in-line carrier receiver comprising a measuring device.

STATE OF THE ART Many techniques are already known for measuring an electric current. Measuring electrical current becomes tricky when it comes to accurately measuring electrical current intensities that are very low. Indeed, the known measurement techniques are intrusive. As a result, the electric current is disturbed by the measuring element and the measurement is erroneous.

SUMMARY OF THE INVENTION An object of the invention is to provide a current measuring device remedying the disadvantages mentioned above and improving the measuring devices known from the prior art. In particular, the invention provides a non-intrusive measuring device, having a high sensitivity and high accuracy. For this purpose, the measuring device makes it possible to measure an electric current flowing inside a medium that is distinct from the device. The measuring device comprises an assembly comprising a plurality of measuring elements, each measuring element being in magnetic coupling with the medium in which the current to be measured flows. The measuring elements are connected in series and / or in parallel with each other. The measuring device comprises an element for analyzing and / or processing an electrical signal at the terminals of the assembly.

At least some of the measurement elements can be juxtaposed to each other in the middle axis in which the electric current flows. At least some of the measurement elements may be arranged around each other. The measuring device may comprise a delay element associated with at least one measuring element. The measuring device may be intended to surround a medium of the electrically conductive type, in particular an electrical conducting wire, and / or to be intended to surround a fluid medium in which the electric current circulates and / or to be intended to surround a void in which circulates the electric current. The measuring elements may be intended to surround a medium of the electrically conductive type, in particular an electrical conducting wire, and / or to be intended to surround a fluid medium in which the electric current circulates and / or to be intended to surround a void in which circulates the electric current.

Each measuring element may comprise a winding, in particular a winding formed on a magnetic core surrounding the medium in which the current to be measured flows.

The starts and / or ends of the windings may be angularly distributed equally or at least substantially equally around a path in which the electric current moves or around a direction perpendicular or substantially perpendicular to the annular cores.

According to the invention, an in-line carrier receiver may comprise a measuring device as defined above.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings show, by way of example, several embodiments of a measuring device according to the invention.

Figure 1 is a schematic view of a first embodiment of a measuring device according to the invention. Fig. 2 is an electrical diagram of the first embodiment of the first embodiment of a measuring device according to the invention. Figure 3 is a schematic view of a second embodiment of a measuring device according to the invention. FIG. 4 is an electrical diagram of the second embodiment of the measuring device according to the invention.

Figure 5 is a schematic view of a first variant of an embodiment of the measuring device according to the invention.

Figure 6 is a schematic view of a second variant of an embodiment of the measuring device according to the invention. Figure 7 is a schematic view of a third variant of an embodiment of the measuring device according to the invention. Figure 8 is a schematic view of a fourth variant of an embodiment of the measuring device 15 according to the invention. Figure 9 is a schematic view of a first arrangement of measuring elements of a measuring device according to the invention. Fig. 10 is a schematic view of a second arrangement of measuring elements of a measuring device according to the invention. Fig. 11 is a schematic view of a third arrangement of measuring elements of a measuring device according to the invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS A first embodiment of a measuring device 10 is described hereinafter with reference to FIGS. 1 and 2. The device makes it possible to measure an electric current flowing inside a device. middle 19 distinct from the device. The measuring device makes it possible in particular to measure very small currents, of the order of the microampere or even the nanoampere, with good sensitivity and good accuracy. The measuring device comprises a mounting 12 comprising a plurality of measuring elements 13a, 13b. Each measuring element is in magnetic coupling with the medium in which the current to be measured flows. The measuring elements are connected in series and / or in parallel with each other. The measuring device further comprises an analysis element 14 and / or processing an electrical signal 20 at the terminals of the assembly. By choosing a good arrangement of the measuring elements, it is possible to obtain an impedance of the assembly seen from its terminals which allows a non-intrusive, sensitive and precise measurement. To do this, a number of sets of measuring elements are arranged in parallel in which the measuring elements are arranged in series. In the embodiment of Figures 1 and 2, two sets connected in parallel of three measuring elements 30 are shown.

The analysis element 14 and / or the processing of the electrical signal at the terminals of the circuit makes it possible to determine signal characteristics, such as a voltage, and to convert them into a characteristic, in particular the intensity, of the electric current. measure. The signal analysis and / or processing element comprises hardware and / or software elements enabling analysis and / or processing and / or conversions necessary for determining the characteristic of the electric current. The electric current to be measured flows in a medium near the measuring elements. The medium may be of the electrically conductive type, especially an electrical conductor, the medium may also be a fluid or a vacuum. The current may be constituted by any displacement of charge carriers. It may be a load carrier displacement in an electrical conductor, such as electron displacement. It can also be a displacement of charge carriers in a fluid, such as an ion displacement. It can still be a beam of charge carriers in a vacuum. Each measuring element 13a, 13b comprises a coil 131, in particular a coil formed on a magnetic core 132 surrounding the medium in which the current to be measured flows. In the first embodiment, two sets connected in parallel of three coils 131 are shown. The magnetic cores have annular shapes, especially annular shapes with a square, rectangular or circular section. It is also possible to arrange in series a number of sets of measuring elements in which the measuring elements are arranged in parallel. A second embodiment of the measuring device is described hereinafter with reference to FIGS. 3 and 4. This second embodiment differs from the first embodiment only in the parallel / series connection of the measuring elements of the arrangement. Indeed, in the second embodiment, two sets of three measuring elements connected in parallel are connected in series. In this second embodiment, the first digit of the numerical references is changed from "1" to "2" to identify identical or similar elements or providing the same function in both embodiments. Figure 5 illustrates the arrangement of the different measurement elements in space. Note that the different measuring elements are juxtaposed parallel to each other and perpendicular to the path taken by the electric current to be measured, in particular perpendicular to the axis of the medium in which the electric current to be measured flows. Here, six measurement elements are represented. However, another number of measurement elements could be juxtaposed. This arrangement is applicable to both the first embodiment and the second embodiment. Figure 9 illustrates a variant in which there is shown a housing 38 encompassing the various measuring elements.

Figure 6 illustrates another alternative arrangement of the measuring device. In this variant, the electric current flows in a medium delimited by an enclosure 19. For example, the enclosure may consist of a tube in which a vacuum is formed and in which charge carriers are displaced, such as an electron beam. In other variants shown in Figures 7 and 8, the device comprises delay elements 16 associated with one or more measuring elements. These delay elements make it possible to compensate for dispersions that may occur when measuring a current exhibiting characteristics of a transient or even more generally non-constant current, which would also be due to the juxtaposed arrangement of the measuring elements along the path taken by the current. It is clear that charge carriers whose displacement constitutes the electric current to be measured move at a speed greater or less than the speed of the electrons moving in the cables connecting the measuring elements to the analysis element and or of treatment, the delay elements must be arranged at different places in the measuring device. The delay elements may simply consist of a length of cable adapted to connect the measuring elements to the analysis and / or processing element. To illustrate the interest of such delay elements, suppose in FIG. 7 that the current to be measured consists of an electron beam emitted for a very short time of the order of one nanosecond, or even less. The electrons of the beam first pass at a first measuring element, then a second measuring element and finally a third measuring element. It follows that the first measuring element first transmits an electrical signal to the analysis and / or processing element, then the second measurement element emits an electrical signal in the second, and finally the third element of measurement. measurement emits in third an electrical signal. If the lengths of the electrical cables connecting the different measuring elements to the analysis and / or processing element are the same, the three signals arrive at the level of the analysis and / or treatment element one after the other. others and one does not obtain the expected effect of summation of the currents of the different signals for which the three measuring elements are connected in parallel. It is therefore necessary to introduce delay elements making it possible to ensure that the different electrical signals arrive simultaneously or as simultaneously as possible at the level of the analysis and / or treatment element.

To remedy this problem of time shift of the signals emitted by the measuring elements, it is possible, in an alternative embodiment of the measuring device, to arrange the measuring elements as shown in FIG. 10. The measuring device 40 comprises different measuring elements 43a, 43b disposed in the same plane or substantially in the same plane, around each other, and perpendicularly or substantially perpendicular to the direction in which the electric current moves. In this variant, the device comprises an enclosure 49 defining a medium in which the electric current to be measured is propagated. Such a variant makes it possible to overcome the aforementioned problems of delay of the various signals arriving at the level of the analysis and / or processing element, assuming that the lengths of the wiring connecting the different measuring elements and the element analysis and / or treatment are the same. In the variant shown, the different measuring elements are also included in a housing 48.

Finally, in another variant shown in FIG. 11, the measuring device 50 comprises different measuring elements 53a, 53b oriented differently relative to each other, in particular oriented differently with respect to one another at their winding ends. 531a, 531b. Indeed, the beginnings and / or ends of the coils are angularly distributed equally or at least substantially equally around the path 57 along which the electric current moves or around a direction perpendicular or substantially perpendicular to the annular cores of the measuring elements. In the example, the four measuring elements are offset from each other by 90 °. Of course the angular offset could be different. More generally, the n measuring elements of the measuring device could be shifted angularly by 2xn / n or substantially 2xn / n.

Preferably, in the various embodiments and / or variants, the measuring elements use a magnetic coupling phenomenon between an electromagnetic element and the medium in which the current to be measured moves. Preferably, this coupling is performed by locating the medium in which the current flows in an annular ring or ring of magnetic material and winding is performed on this ring. The passage of the electric current causes a magnetic flux in the core, this magnetic flux causing another electric current in the coil. In this way, a current transformer is actually made at each measuring element.

In particular, a current transformer comprising a single winding is produced. Such a transformer nevertheless has a defect: its sensitivity to the primary current increases if the current does not pass through the geometric center of the measuring element. When the current is moved laterally, the sensitivity increases as the current approaches the core, and particularly as it approaches the place where the winding begins and ends on the core. Winding techniques can reduce this phenomenon without ever eliminating it. However, these drawbacks can be limited by arranging the different measuring elements as described above with reference to FIG. 11. Thus, the winding starts and ends can be angularly distributed so as not to be aligned. Thus, when the currents from these coils are combined with each other, the sensitivity to the phenomenon is limited. In the various embodiments and variants, the measuring device is intended to surround a medium of the electrically conductive type, in particular an electrical conducting wire, and / or intended to surround a fluid medium in which the electric current flows and / or intended to surround a vacuum in which the electric current flows. In particular, the measuring elements are intended to surround a medium of the electrically conductive type, in particular an electrical conducting wire, and / or intended to surround a fluid medium in which the electric current flows and / or intended to surround a vacuum in which the Electric power. The invention also relates to an in-line carrier receiver comprising a measuring device according to the invention, in particular a measuring device according to one of the embodiments and / or variants described above. Such a receiver is used to receive electrical signals containing information, these electrical signals being superimposed on power signals transmitting energy on the power line.

The measuring device according to the invention has many advantages including: a greater sensitivity to the current to be measured, a high frequency bandwidth, a source impedance of the device different from that of some and / or each of the measuring elements interconnected, a compensation of the difference in propagation speed between the current to be measured and the measurement of this current, a reduced sensitivity of the device to measurement errors when the current is moved laterally and approaches the nuclei of the measuring elements.

Claims (8)

REVENDICATIONS1. Apparatus (10; 20; 30; 40; 50) for measuring an electric current flowing inside a medium (19; 39; 49) separate from the device; the measuring device comprising a mounting (12; 22) comprising a plurality of measuring elements (13a, 13b; 23a; 23b; 33a; 33b; 43a; 43b; 53a; 53b), each measuring element being magnetically coupled with the medium; wherein the current to be measured flows, the measuring elements being connected in series and / or in parallel with each other, the measuring device comprising an analysis element (14; 24) and / or processing element (15; 25) of an electrical signal at the terminals of the assembly. 2. Measuring device according to one of the preceding claims, characterized in that at least some of the measuring elements are juxtaposed to each other in the axis of the medium in which the electric current flows. 3. Measuring device according to one of claims 1 to 3, characterized in that at least some of the measuring elements (43a, 43b) are arranged around each other. 4. Measuring device according to one of the preceding claims, characterized in that it comprises a member (16; 26) delay associated with at least one measuring element. 5. Measuring device according to one of the preceding claims, characterized in that it is intended to surround a medium of the electrically conductive type, including an electrical conductor wire, and / or for surrounding a fluid medium in which the current flows. electrical and / or intended to surround a vacuum in which the electric current circulates, in particular characterized in that the measuring elements (13a, 13b; 23a, 23b; 33a, 33b; 43a, 43b; 53a, 53b) are intended to surround a medium of the electrically conductive type, in particular an electrical conductor wire, and / or intended to surround a fluid medium in which the electric current flows and / or intended to surround a vacuum in which the electric current flows. 6. Measuring device according to the preceding claim, characterized in that each measuring element comprises a coil (131; 231; 531a, 531b), in particular a coil formed on a magnetic core (132; 232; 532a, 532b) surrounding the medium where the current to be measured flows. 7. Measuring device (50) according to the preceding claim, characterized in that the beginnings and / or ends of the windings are equally angularly or at least substantially equally distributed around a path (57) in which the electric current moves or around a direction perpendicular or substantially perpendicular to the annular cores. 8. In-line carrier receiver comprising a measuring device according to one of the preceding claims.