Support for a system for measuring at least one parameter of an electrical cable

Abstract

This support, suitable for being positioned around an electrical cable in a removable manner, contains a system for measuring at least one parameter of the cable. The measurement system comprises measuring devices and measurement processing devices connected thereto. It is made in two parts each at least partially housing the measuring devices. Each part has first and second ends. The two parts are assembled at their first end by means of an articulation about a first axis of the support. The two parts of the support each also at least partially house the processing devices. The support comprises at least one retaining element for holding the processing devices in position with respect to the support. The two parts of the support do not come into contact with each other in a region extending from the articulation as far as the second ends inclusive, along a second axis of the support perpendicular to the first axis.

Description

Description Title of the invention: SUPPORT FOR A SYSTEM FOR MEASURING AT LEAST ONE PARAMETER OF AN ELECTRIC CABLE

[0001] The present invention relates to a support for a system for measuring at least one parameter of an electric cable.

[0002] The invention belongs to the field of electric cables intended for the transport of energy and / or the transmission of data. It finds application in particular in the field of optimizing the distribution of energy in buildings. The support which is the subject of the present invention can for example be used there as a support for a device for simultaneously measuring the intensity of the instantaneous current in each phase or in each conductor of an electric cable with alternating or direct current, single-phase or multi-conductor or polyphase.

[0003] Document EP 2 776 853 B1 discloses a device for measuring currents in the conductors of a sheathed cable of a polyphase network.

[0004] This prior art measuring device is in the form of a measuring ring intended to surround a section of the sheathed cable. The ring comprises two articulated parts fixed to each other by a clasp which holds the ring in position on the cable.

[0005] For measuring currents, this known measuring device comprises at least three magnetic sensors arranged around a central orifice intended to be crossed by the cable to be measured when the measuring ring surrounds the cable. The ring comprises a number of magnetic sensors greater than the number of conductors whose current is to be measured.

[0006] This known device also comprises a calculation device configured to: access a library of matrices [K] and [K] +, with [I] = [K] + .B for a given cable configuration and a given angular position of the sensors around this given cable, [I] being a current vector passing through the cable having the given configuration when a magnetic field vector [B] is measured on the sensors and [K] + being a pseudo-inverse matrix of the matrix [K]; form a vector [B] including a magnetic field measurement of each of the sensors; for different cable configurations and different angular positions of the sensors relative to these cables, calculate a residual vector [R] = [K].[K] + .[B] - [B] ; select matrix [K] + for which the norm of the vector [R] is minimal; calculate [I] = [K] + .B, where [K] + is the selected matrix.

[0007] This known measuring device has several drawbacks.

[0008] On the one hand, its use requires the creation and maintenance of a matrix library and the management of access to this library, which consumes in particular time for the creation and updating of the library, storage space to store the library and electrical energy to carry out all the operations related to the existence and use of the library.

[0009] On the other hand, the quality and repeatability of the measurement are not guaranteed: document EP 2 776 853 B1 does not in fact mention any means of maintaining in position specifically concerning the electronic means of processing the magnetic field measurements carried out on the cable, when the measuring device is positioned around this cable, nor any means of protecting these electronic processing means, neither against degradation linked to the conditions of the environment in which the device is located, for example due to weather conditions, nor against degradation due to a mechanical action such as deformation under pressure, or even crushing.

[0010] Other known devices for measuring the instantaneous current intensity in each conductor of a polyphase or multi-conductor cable generally consist of successively measuring, by means of an ammeter clamp, the current intensity in each of the conductors.

[0011] These operations are time-consuming and generally provide imprecise results.

[0012] Therefore, there is no practical technical solution on the market that allows one or more parameters of an electrical cable to be measured quickly and with high measurement quality, i.e. not only accurately, but also with a reduced risk of damage to the measuring device.

[0013] The present invention aims to remedy the aforementioned drawbacks of the prior art.

[0014] For this purpose, the present invention provides a support containing a system for measuring at least one parameter of an electric cable, according to claim 1.

[0015] The present invention makes it possible to improve the quality of the measurement carried out.

[0016] Indeed, on the one hand, measurements of great precision and excellent repeatability are obtained by maintaining the measurement processing device(s) in position relative to the support and, on the other hand, the risk of damage to this / these processing device(s) is reduced by the fact that the first and second parts of the support never come into contact, that is to say that there is always a free space between the two parts of the support, whether the latter is in the open or closed position.

[0017] This free space in fact makes it possible to avoid mechanical contact between the first and second parts of the support in the closed position, whether this closed position is taken when the measuring device is not in use and is for example stored or transported, or whether it is taken when the measuring device is placed around a cable of which it is desired to measure at least one parameter by means of the measuring device. Thus, the treatment device presents a very reduced risk of deformation and crushing when the support is closed.

[0018] Furthermore, the support according to the invention is easy to install around the cable, since it is not necessary to install each measuring device individually.

[0019] The invention offers numerous applications, such as the identification of unbalanced current distributions which sometimes reveal a faulty power supply, the anticipation of cable failures when a conductor reaches an excessive temperature or even the reduction of electrical energy consumption in an installation.

[0020] In a particular embodiment, the element for holding the at least one treatment device in position relative to the support is a locking clip.

[0021] However, this embodiment is not limiting, because any other mechanical system which ensures this maintenance in position can be used.

[0022] The at least one measuring device comprises at least one magnetic field sensor and the at least one measurement processing device comprises at least one integrated circuit card, called PCB in English ("Printed Circuit Board"), the at least one parameter being, in this particular embodiment, the intensity of an instantaneous current flowing in the cable.

[0023] As examples of use of the support which are in no way limiting: when the cable is single-phase, the at least one measuring device is adapted to measure the intensity of the instantaneous current flowing in the phase of the cable; when the cable is a multi-conductor cable, the at least one measuring device is adapted to simultaneously measure the intensities of the instantaneous currents flowing respectively in all the conductors of the cable; and when the cable is polyphase, the at least one measuring device is adapted to simultaneously measure the intensities of the instantaneous currents flowing respectively in all the phases of the cable.

[0024] The at least one measurement processing device comprises two integrated circuit cards respectively housed in the first and second parts of the support and the two integrated circuit cards can be in mutual mechanical contact. Thus, the maintenance in position of the measurement processing device relative to the support is even better.

[0025] By way of non-limiting example, in the case where the measuring device comprises several magnetic field sensors, these sensors can for example be arranged on the integrated circuit cards, for example in a distributed manner. If for example the first and second parts of the support are half-rings, the sensors can be distributed in each of the first and second parts on the circumference of a semicircle. In such a non-limiting example of embodiment, the mechanical contact between the two integrated circuit cards when the support is in the closed position allows the magnetic sensors to form a perfect circle, which further increases the accuracy of the measurement.

[0026] In this particular embodiment, the element for holding the at least one processing device in position relative to the support makes it possible to ensure that the two integrated circuit cards remain in mutual mechanical contact.

[0027] In this particular embodiment where the at least one measuring device comprises at least one magnetic field sensor and the at least one measurement processing device comprises at least one integrated circuit card, the at least one parameter being the intensity of an instantaneous current flowing in the cable, the first and second parts can be surrounded by electromagnetic shielding.

[0028] This shielding prevents the penetration of electromagnetic disturbances which could distort the measurement. These disturbances could be due, for example, to the Earth's permanent magnetic field and to possible sources of electromagnetic field located near the cable and the sensors.

[0029] In a particular embodiment, the support further comprises at least one additional magnetic field sensor adapted to measure the Earth's magnetic field.

[0030] This allows the value of the Earth's magnetic field to be taken into account, which can then be subtracted when processing the magnetic field values ​​collected by the sensors.

[0031] According to a particular feature, the at least one additional sensor can be housed in the support, which makes it possible to better protect this sensor against damage and to obtain a compact support.

[0032] Alternatively, the at least one additional sensor may be arranged on the support and outside the support, making it more accessible.

[0033] According to a particular characteristic, the at least one additional sensor can be removable, which allows the user of a single support to opt on a case-by-case basis for a version of the support with or without this additional sensor.

[0034] In a particular embodiment, the joint is a hinge.

[0035] In the particular embodiment where the processing device comprises two integrated circuit cards housed respectively in the first and second parts of the support, the hinge, which implements a pivot connection allowing rotation but blocking translation, guarantees mutual mechanical contact between the two integrated circuit cards.

[0036] Alternatively, the joint may be a ball joint, which provides more degrees of freedom for the first and second parts of the bracket and makes it easier to position them around a cable.

[0037] In a particular embodiment, the first and second parts are half-rings, the annular shape being particularly suitable for positioning the support around a cable.

[0038] This configuration allows for rapid installation of the support around the cable, which is therefore housed in the center of the circular opening formed by the meeting and closing of the two half-rings, thus forming a ring crossed in its center by the cable to be measured.

[0039] In a particular embodiment, the support further comprises a communication device adapted to transmit to the outside data originating from the at least one measuring device and / or from the at least one processing device.

[0040] This makes it possible, for example, to provide the data transmitted to various recipients, who will be able, by reading this data and possibly analyzing it, to decide on actions to be taken with regard to the cable measured and the installation served by this cable.

[0041] According to a particular characteristic, the communication device may comprise at least one antenna, which is a simple means of transmitting data over the air, for example via radio frequency waves.

[0042] For the same purpose as that indicated above, the present invention further provides an electrical cable arrangement comprising an electrical cable comprising a plurality of conductors, remarkable in that it further comprises at least one support as succinctly described above placed around the cable.

[0043] The cable arrangement according to the invention has the same advantages as the support.

[0044] In a particular embodiment, the cable arrangement comprises a plurality of supports such as that described briefly above, placed around the cable at predetermined intervals from each other.

[0045] This ensures adequate measurement of current intensities in the cable conductors in the event that these conductors are twisted in such a way that they are likely to influence the sensitivity of the current measurement.

[0046] Still for the same purpose as that indicated above, the present invention also proposes a method for measuring the intensity of the current in an electric cable comprising a plurality of conductors by means of at least one measuring device and at least one measurement processing device, the at least one measuring device and the at least one processing device forming part of a support as succinctly described above, the measuring device comprising a plurality of magnetic field sensors, the method being remarkable in that it consists in simultaneously measuring the intensity of the current in the conductors of the plurality of conductors, by means of the at least one measuring device and the at least one processing device, by carrying out steps consisting in: placing the plurality of magnetic field sensors around the cable, at at least one location of the cable;simultaneously measuring, for each of the conductors, at least one component of the magnetic field produced by the current flowing in the conductor, by means of the plurality of magnetic field sensors; for each of the conductors, determining the angle between the conductor and the nearest magnetic field sensor of the plurality of magnetic field sensors, this angle being defined relative to the center of the cable and by assimilating the conductors and the sensors to points; the intensities of the currents in the conductors being linked to the components of the magnetic field measured by the relation B = kMI where B is the matrix of the components of the magnetic field, I is the matrix of the intensities of the currents, M is a matrix comprising a plurality of proportionality coefficients depending on the angles between the conductors and the magnetic field sensors and k is a predetermined coefficient, calculating the inverse M; -1 of the matrix M, so as to deduce the values ​​of the current intensities I = (|JO / 2TT).M' 1 .B, WHERE po is an equivalent magnetic permeability which takes into account the presence of insulating materials in the cable, the at least one measurement processing device being adapted to receive the values ​​of the components of the magnetic field and to apply the steps of angle determination and inverse matrix calculation to deduce therefrom the intensity of the current flowing in each of the conductors.

[0047] The method according to the invention has the same advantages as the support.

[0048] Furthermore, with regard more particularly to the measurement of the intensity of the current(s) flowing in a cable, the method according to the invention makes it possible in particular to measure in a single operation the intensity of the current in all the conductors of the cable and to quickly obtain extremely precise results, without needing to remove the sheath of the cable. Furthermore, the installation of the magnetic field sensors around the cables is easy and does not cause any damage, marks or deformation to the cables. Furthermore, given that the position of the magnetic field sensors relative to the conductors of the cable is unknown, taking into account the angular offset between sensors and conductors makes it possible to increase the accuracy of the intensity values ​​obtained.

[0049] In a particular embodiment, the measuring step consists of simultaneously measuring, for each of the conductors, the tangential component and the radial component of the magnetic field produced by the current flowing in the conductor, by means of the plurality of magnetic field sensors.

[0050] This makes it possible to minimize the error in the intensity values ​​obtained, i.e. to further increase the precision of these values. Brief description of the drawings

[0051] Other aspects and advantages of the invention will appear on reading the detailed description below of particular embodiments, given as non-limiting examples, with reference to the appended drawings, in which:

[0052] [Fig. 1] is a schematic view illustrating one aspect of the technical problem to which the support according to the present invention provides a solution.

[0053] [Fig. 2] is a schematic representation of a support according to the present invention, in a non-limiting example of application to the measurement of a five-conductor electric cable.

[0054] [Fig. 3] is a schematic representation of an electrical cable support and arrangement according to the present invention, in a particular embodiment.

[0055] [Fig. 4] is a schematic representation of an electrical cable arrangement according to the present invention, in another particular embodiment.

[0056] [Fig. 5] is a flowchart illustrating steps of a method according to the present invention, in a particular embodiment.

[0057] [Fig. 6] is a geometric representation illustrating different parameters used in a method according to the present invention, in a non-limiting example where the electric cable considered comprises five conductors. Description of embodiment(s)

[0058] Figure 1 illustrates one aspect of the problem addressed by the present invention: it is a theoretical view which schematically represents a relative position that two parts of measurement processing devices could take, for example two integrated circuit cards 11 and 12, these two integrated circuit cards being adapted to process measurements carried out on an electric cable 32 comprising a plurality of conductors 34.

[0059] The two integrated circuit cards 11 and 12 are respectively housed in two parts of a support (not illustrated in FIG. 1, described in detail later with reference to FIG. 2). The two parts of the support close over the cable 32 for carrying out measurements and processing these measurements of one or more parameters of the cable 32, for example physical parameters such as the current flowing therein and / or the temperature and / or the degree of humidity and / or any other quantity relating to the cable 32 itself and / or the current flowing through it. The processing of the measurements carried out on the cable is carried out by the integrated circuit cards 11 and 12.

[0060] As shown in Figure 1 in a magnified manner compared to reality, when the two parts of the support close on the cable 32 and are tightened around it, an angle R can form between the planes of the two integrated circuit cards 11 and 12, which can induce a deformation of one or the other or of both cards 11 and 12, or even of the entire support. This can then cause errors in the measurements carried out and / or in the processing of these measurements, for example in the determination of the intensity of the instantaneous current(s) flowing in the cable 32. The repeatability of the measurements can be compromised. The reliability and quality of the measurements can be significantly affected.

[0061] Figure 2 shows a support 20 in accordance with the present invention providing a solution which notably resolves this problem.

[0062] The support 20 contains a system for measuring at least one parameter of the electric cable 32.

[0063] The support 20 is adapted to be positioned around the cable 32 in a removable manner.

[0064] The measuring system comprises at least one device for measuring the at least one parameter and at least one device for processing measurements of the at least one parameter. The at least one processing device is connected to the at least one measuring device.

[0065] The support 20 is made of a first part 21 and a second part 22. The first part 21 houses at least one part of the at least one measuring device and likewise, the second part 22 houses at least one part of the at least one measuring device.

[0066] The first and second parts 21, 22 of the support 20 each have a first end (designated in the drawing by the reference 210 for the first part 21 and by the reference 220 for the second part 22) and a second end (designated in the drawing by the reference 230 for the first part 21 and by the reference 240 for the second part 22).

[0067] The first and second parts 21, 22 of the support 20 are assembled at their first end 210, 220 by means of an articulation 26 along a first axis of the support 20 designated in the drawing by the reference z. The articulation 26 makes the first and second parts 21, 22 of the support 20 movable around the first axis z.

[0068] In accordance with the present invention, the first and second parts 21, 22 of the support 20 each further house at least one part of the at least one processing device, which in the particular embodiment shown in FIG. 2 is the assembly formed by the integrated circuit cards 11 and 12.

[0069] According to the present invention, the support 20 further comprises at least one element for holding the at least one treatment device in position relative to the support 20. The element for holding the at least one treatment device in position relative to the support 20 may for example be a locking clip.

[0070] According to the present invention, the first and second parts 21, 22 of the support 20 do not come into mutual contact in a region extending from the articulation 26 to the second ends 230, 240 inclusive, along a second axis of the support, designated in the drawing by the reference x. The second axis x is perpendicular to the first axis z. In other words, there is always a free space 24 between the first part 21 of the support 20 and the second part 22 of the support 20.

[0071] Figure 3 illustrates a particular embodiment of the invention in which the measured parameter is the intensity of an instantaneous current flowing in the electric cable 32.

[0072] The cable 32 may be a single-phase or polyphase or multi-conductor cable and may carry an alternating current or a direct current. N denotes the number of conductors in the cable. These conductors are not necessarily identical.

[0073] In the non-limiting example of Figure 3, the cable 32 is polyphase and the invention is based on the local measurement of at least one component of the magnetic field emitted by the current sources, which are here the N conductors, by means of magnetic field sensors. Thus, the at least one measuring device comprises at least one magnetic field sensor 36 and the at least one measurement processing device comprises at least one circuit card 11, 12 integrated, the at least one parameter being the intensity of an instantaneous current flowing in the cable 32.

[0074] In short, since a polyphase cable has several current densities coming from its N conductors, we can first calculate the magnetic field produced by the current using the Biot-Savart law, then invert all the local measurements of the magnetic field components by determining an inverse matrix, in order to obtain the current intensities coming from the N current sources.

[0075] Thus, as shown in the flowchart of Figure 5, the method, according to the invention, for measuring the current intensity in an electric cable comprising a plurality of conductors, consists in simultaneously measuring, by means of at least one measuring device and at least one measurement processing device, the current intensity in the conductors of the plurality of conductors 34 by carrying out a first step E1 consisting in placing a plurality of magnetic field sensors 36 around the cable 32, at at least one location of the cable. The at least one measuring device and the at least one processing device are part of a support 20 according to the present invention.

[0076] Step E1 may for example consist of fixing around the cable 32 one or more supports 20 in accordance with the invention containing the plurality of sensors 36. The support 20 in accordance with the invention is described further below.

[0077] Then a step E2 consists of simultaneously measuring, for each of the conductors 34 of the cable 32, at least one component of the magnetic field produced by the current flowing in this conductor.

[0078] These simultaneous measurements are carried out by means of the measuring device which comprises the plurality of magnetic field sensors 36.

[0079] In a particular embodiment, the plurality of magnetic field sensors 36 can measure for each conductor 34 only the tangential component or only the radial component of the magnetic field.

[0080] Alternatively, for greater accuracy, the plurality of magnetic field sensors 36 can measure for each conductor 34 both and simultaneously the tangential component and the radial component of the magnetic field.

[0081] Then, during a step E3, for each of the conductors, the angle a is determined between this conductor and the nearest magnetic field sensor of the plurality of magnetic field sensors. The angle a is defined relative to the center of the cable section and by treating the conductors and the sensors as points. Indeed, for simplicity, it is assumed that each conductor has an infinitely small section and that the magnetic field picked up by each sensor is located at a point corresponding to the location of the sensor.

[0082] Figure 6 schematically illustrates, by way of non-limiting example, a cable of circular section comprising five conductors regularly distributed inside the cable, which are assimilated to five points C1 to C5 equidistant from each other on the circumference of a circle T. Only the magnetic field sensor closest to the conductor C1 has been represented and is symbolized by the point A. The radius of the circle T is designated by r, the distance between the conductor C1 and the sensor A is designated by di, the straight line segment connecting the sensor A and the center of the circle T is designated by d'i, the angle at point A between the straight line segment d'i and the straight line segment connecting the conductor C1 and the point A is designated by 0. The magnetic field captured by the sensor A is represented by the vector Bi, which is orthogonal to the straight line segment connecting the conductor C1 and the point A.

[0083] For a cable comprising N conductors each producing a magnetic field Bi, i = 1, N, the component BA of the magnetic field at point A coming from the N conductors is defined as follows:

[0084] [Math. 1]

[0086] Or : Bim is the component of the magnetic field coming from the i ème driver captured by the rn ième sensor; angles ai and pi are defined for the i ème conductor similarly to the angles a and p defined above, respectively; di denotes the distance between the i ème conductor and the nearest sensor; po is an equivalent magnetic permeability which takes into account the presence of insulating materials in the cable; r is as defined above the radius of the circle T; and hm is the value of the intensity of the current flowing in the i ème conductor and deduced from the magnetic field measurement carried out by the m ième sensor.

[0087] The number of magnetic field sensors 36 is at least equal to the total number N of conductors 34 of the cable 32.

[0088] Thus, the intensities of the currents in the conductors are linked to the components of the magnetic field measured, by the relation B = kMI where B is the matrix of the components of the magnetic field measured in all the conductors by all the sensors, I is the matrix of the intensities of the currents circulating in all the conductors, M is a matrix comprising a plurality of proportionality coefficients depending on the angles between the conductors and the magnetic field sensors and k is a predetermined coefficient.

[0089] It follows that I = (po / 2n).M' 1 .B, where M -1 is the inverse matrix of M.

[0090] Thus, as shown in Figure 5, following step E3 of determining the angle a between each conductor and the nearest sensor, a step E4 is carried out consisting of calculating the inverse matrix M -1 , so as to deduce the values ​​of the intensities I of the currents in all the conductors of the cable.

[0091] As a non-limiting example, for N = 5 conductors and five magnetic field sensors placed respectively at points A, B, C, D and E, the analytical expression allowing the intensities of the currents in the conductors to be deduced is as follows:

[0092] [Math. 2]

[0094] where I i , i = 1 , ... , 5 denotes the intensity of the current flowing in the i ème conductor and BA, BB, BC, BD and BE denote the magnetic field components respectively measured by the five sensors.

[0095] The equivalent magnetic permeability po is a macroscopic permeability, which makes the calculation simpler than if we considered the local magnetic permeability.

[0096] In a particular embodiment, the angle α between this conductor and the nearest magnetic field sensor of the plurality of magnetic field sensors is determined so as to maximize the following function F:

[0097] [Math. 3]

[0099] where denotes the intensity of the current flowing in the i ème driver.

[0100] There are various known mathematical convergence methods for maximizing F, such as the Levenberg-Marquardt algorithm (also called the LM algorithm) or the Nelder-Mead method.

[0101] As shown in Figure 3, a support 20 according to the present invention, for measuring the intensity of the current in an electric cable 32 comprising a plurality of conductors 34, comprises a plurality of magnetic field sensors 36 (five in the non-limiting example illustrated) and a processing device comprising integrated circuit cards 11, 12, the processing device being illustrated arbitrarily separately to simplify the view. schematic of Figure 3, but being contained in the first and second parts 11, 12 of the support 20 as described above with reference to Figure 2.

[0102] The processing device is adapted to receive the values ​​of the components of the magnetic field measured by the plurality of sensors 36 and to apply the steps E3 of angle determination and E4 of inverse matrix calculation of the method described above, to deduce therefrom the intensity of the current flowing in each of the conductors 34.

[0103] The support 20 further comprises the first and second parts 11, 12 containing the plurality of magnetic field sensors 36.

[0104] In the particular embodiment illustrated, the support 20 has a section formed by two half-rings 311 and 312, adapted to the positioning of the support 20 around the cable 32, the two half-rings 311 and 312 defining by their assembly an opening in which the cable 32 passes. In the particular embodiment illustrated, the cable 32 has a circular section and the opening formed by the two half-rings 311 and 312 is also circular and of diameter slightly greater than that of the section of the cable.

[0105] Once the support 20 is placed around the cable 32, the two half-rings 311 and 312 can be connected to each other for example by means of an articulation 26 of the hinge type or of the ball joint type, or be secured to each other for example by means of screws or nuts or other preferably removable fixing means.

[0106] Also optionally, the support 20 can be surrounded by electromagnetic shielding preventing the sensors from being disturbed by any surrounding sources of electromagnetic waves as well as by the Earth's permanent magnetic field. This shielding can be made, for example, of a specific steel.

[0107] Whether such shielding is present or not, the support 20 may further be equipped with one or more additional magnetic field sensors 37 adapted to measure in particular the Earth's magnetic field, in order to subtract the value thereof when processing the values ​​of the components of the magnetic field measured by the magnetic field sensors 36. The additional sensor(s) 37 may be housed in the support 20, i.e. inside this and / or outside the support 20. The at least one additional sensor 37 may be removable, for example being removably plugged into or onto the support and thus being able to be disconnected and not be used with the support 20.

[0108] Optionally, the support 20 may further comprise a communication device adapted to transmit to the outside data coming from the at least one measuring device 36 and / or from the at least one device 11, 12 for processing these measurements.

[0109] The communication device may include one or more antennas.

[0110] Thus, an electrical cable arrangement according to the present invention comprises the cable 32 and at least one support 20 placed around the cable 32.

[0111] As shown in the particular embodiment of Figure 4, the electrical cable arrangement may include a plurality of supports 20, placed around the cable 32 at predetermined intervals from each other.

[0112] The processing means 38 may be unique and common to all the supports 20. As a variant, a processing means 38 may be provided for each support 20 and communication means adapted to communication between the various processing means 38 may possibly be provided.

[0113] In the particular embodiment illustrated, the supports 20 are all identical, each comprise five magnetic field sensors 36 and are arranged at regular intervals along the cable 32.

[0114] Such a configuration makes it possible to guarantee high-quality measurement of current intensities even in the case where the conductors 34 are twisted, for example due to manufacturing conditions and / or specific constraints, which could influence the sensitivity of the measurement of magnetic fields.

[0115] The number of supports 20 to be placed around the cable 32 and the distance between each support 20 are of course to be defined according to the type of cable 32 considered.

[0116] The invention can be applied to many types of cables, such as cables used in buildings, which are designed for voltages generally less than 1000 V, and distribution cables, which are designed for voltages generally equal to or greater than 1000 V.

Claims

Claims

1. Support (20) containing a system for measuring at least one parameter of an electric cable (32), said support (20) being adapted to be positioned around said cable (32) in a removable manner, said measuring system comprising at least one device (36) for measuring said at least one parameter and at least one device (11, 12) for processing measurements of said at least one parameter, said at least one processing device (11, 12) being connected to said at least one measuring device (36); said support (20) being made of a first and a second part (21, 22) which each house at least a part of said at least one measuring device;said first and second parts (21, 22) of said support (20) each having a first end (210, 220) and a second end (230, 240), said first and second parts (21, 22) being assembled at their first end (210, 220) by means of an articulation (26) along a first axis (z) of said support, said articulation (26) making said first and second parts (21, 22) of said support (20) movable around said first axis (z); - said first and second parts (21, 22) of said support (20) each further housing at least one part of said at least one processing device (11, 12); - said support (20) further comprising at least one element for holding said at least one treatment device (11, 12) in position relative to said support (20); said support (20) being characterized in that: - said first and second parts (21, 22) of said support (20) do not come into mutual contact in a region extending from said articulation (26) to said second ends (230, 240) inclusive, along a second axis (x) of said support perpendicular to said first axis (z); - said at least one measuring device (36) comprises at least one magnetic field sensor (36), said at least one parameter being the intensity of an instantaneous current flowing in said cable (32); - said at least one measurement processing device (11, 12) comprises two integrated circuit cards respectively housed in said first and second parts of the support (20) and said two integrated circuit cards are in mutual mechanical contact.

2. Support (20) according to claim 1, characterized in that said element for holding said at least one treatment device (11, 12) in position relative to said support (20) is a locking clip.

3. Support (20) according to any one of the preceding claims, characterized in that said first and second parts (21, 22) are surrounded by electromagnetic shielding.

4. Support (20) according to any one of the preceding claims, characterized in that it further comprises at least one additional magnetic field sensor (37) adapted to measure the Earth's magnetic field.

5. Support (20) according to claim 4, characterized in that said at least one additional sensor (37) is housed in said support (20).

6. Support (20) according to claim 4, characterized in that said at least one additional sensor (37) is arranged on said support and outside of said support.

7. Support (20) according to claim 4, 5 or 6, characterized in that said at least one additional sensor (37) is removable.

8. Support (20) according to any one of the preceding claims, characterized in that said articulation (26) is a hinge.

9. Support (20) according to any one of claims 1 to 7, characterized in that said articulation (26) is a ball joint.

10. Support (20) according to any one of the preceding claims, characterized in that said first and second parts (21, 22) are half-rings.

11. Support (20) according to any one of the preceding claims, characterized in that it further comprises a communication device adapted to transmit to the outside data coming from said at least one measuring device (36) and / or said at least one processing device (11, 12).

12. Support (20) according to the preceding claim, characterized in that said communication device comprises at least one antenna.

13. An electrical cable arrangement comprising an electrical cable (32) comprising a plurality of conductors (34), characterized in that it further comprises at least one support (20) according to any one of the preceding claims placed around said cable (32).

14. An electrical cable arrangement according to claim 13, characterized in that it comprises a plurality of supports (20) according to any one of claims 1 to 12, placed around said cable (32) at predetermined intervals from each other.

15. A method for measuring the current intensity in an electric cable (32) comprising a plurality of conductors (34) by means of at least one measuring device (36) and at least one measurement processing device (11, 12), said at least one measuring device (36) and said at least one processing device (11, 12) being part of a support (20) according to any one of claims 1 to 12, said measuring device (36) comprising a plurality of magnetic field sensors (36), said method being characterized in that it consists in simultaneously measuring the current intensity in the conductors (34) of said plurality of conductors, by means of said at least one measuring device (36) and said at least one processing device (11, 12), by carrying out steps consisting in: placing (E1) said plurality of magnetic field sensors (36) around said cable (32), at at least one location of said cable (32);measuring (E2) simultaneously, for each of said conductors (34), at least one component of the magnetic field produced by the current flowing in said conductor (34), by means of said plurality of magnetic field sensors (36); for each of said conductors (34), determining (E3) the angle between said conductor and the nearest magnetic field sensor (36) of said plurality of magnetic field sensors, said angle being defined relative to the center of said cable (32) and by assimilating said conductors (34) and said sensors (36) to points; the intensities of the currents in said conductors (34) being linked to the components of the magnetic field measured by the relation B = kMI where B is the matrix of said components of the magnetic field, I is the matrix of said intensities of the currents, M is a matrix comprising a plurality of proportionality coefficients depending on said angles between said conductors (34) and said magnetic field sensors (36) and k is a predetermined coefficient, calculate (E4) the inverse M -1 of the matrix M, so as to deduce the values ​​of the said intensities of the currents I = (po / 2n).M' 1.B, where po is an equivalent magnetic permeability which takes into account the presence of insulating materials in said cable, said at least one measurement processing device (11, 12) being adapted to receive the values ​​of said components of the magnetic field and to apply the steps (E3, E4) of angle determination and inverse matrix calculation to deduce therefrom the intensity of the current flowing in each of said conductors (34).

16. Method according to the preceding claim, characterized in that the measuring step (E2) consists of simultaneously measuring, for each of said conductors (34), the tangential component and the radial component of the magnetic field produced by the current flowing in said conductor (34), by means of said plurality of magnetic field sensors (36).

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