A device for injecting a current into a magnetic and / or metallic structure to generate a signal measurable by magnetometric sensors, and an associated mapping device for monitoring the condition and / or geolocating said structure.

Abstract

The present invention relates to a device for injecting a current into a magnetic and / or metallic structure to generate a signal measurable by magnetometric sensors, as well as an associated mapping device. The injection device comprises: input connection means for a power supply; output connection means for electrical connection points of said structure; a voltage conversion stage for the power supply, including an inverter and processing means for generating a DC output voltage at at least one determined frequency; and a filtering stage for controlling the envelope of the current injected into the structure, enabling a response from the structure measurable by magnetometric sensors. Figure for the abstract: Fig. 4

Description

Title of the invention: Device for injecting a current into a magnetic and / or metallic structure to generate a signal measurable by magnetometric sensors, and associated mapping device for state monitoring and / or geolocation of said structure technical field

[0001] The present invention relates primarily to a device for injecting a current into a magnetic and / or metallic structure to generate a signal measurable by magnetometric sensors. The invention will find application in the location of pipelines, particularly for the transfer of liquids or gases. The invention can also be used for the detection and geolocation of other types of structures or in geophysical surveys. Furthermore, the invention can be used in the external monitoring of structures, both for verifying the integrity of the structure and for assessing the magnetic connection between two adjacent structures. Technological background

[0002] Various detection methods using magnetometers for detecting non-visible structures are known. Among these methods, a first, so-called passive method, is known in which the sensors record the magnetic signal emitted by the ground including the structures to be detected, and a second, so-called active method, is known in which a current is injected into the structure to measure the response of the structure under voltage.

[0003] The present invention relates to the field of active detection. To implement this active method, a current is injected at a known location on the structure. In the case of pipelines, potential tapping points or tapping stations installed during pipeline installation are generally used.

[0004] During the current injection, measurements are carried out in a conventional manner, in particular by scanning the sector to be controlled, using magnetometers, then a 2D or 3D geolocation map is generated from the collected data, combining the measurements and the positioning of the sensors.

[0005] Up to now, current injection has been carried out by standard current generators whose purpose is simply to convert an input current to supply current to an electrical receiver. The characteristics of the current generated by this type of generators are not very precise and constant, therefore the use of these current generators is a source of errors for sensor measurements and their operation.

[0006] More specifically, one of the problems with these generators is that, in particular, the injected current is neither sufficient nor stable during injection.

[0007] Another problem is that the generators cannot optimally vary the injection frequency, moreover the spectrum of these frequencies is too wide and again generates responses from random structures resulting in unusable measurements or measurement anomalies.

[0008] Another problem is that the generators send, after adjustment, a voltage that cannot be modified according to different parameters such as the dimensions of the pipeline or according to the measurements obtained by the sensors or even possible interferences in the field.

[0009] It follows from this that operators must manually carry out many tests with current generators to obtain results, the latter being of insufficient quality and random.

[0010] Finally, from another perspective, the injection points in the structure under study are, in most practical cases, outdoors and exposed to the elements. Standard generators used under these conditions are not suitable; in particular, humidity or shocks cause frequency drifts in the injected current that cannot be compensated for in the field.

[0011] Technical problem to be solved

[0012] A technical problem that the present invention aims to solve is to provide a new injection device in which the characteristics of the injected current ensure stability of the response of the structure allowing exploitation of the signals received by the sensors.

[0013] Another problem that the present invention aims to solve is to provide an injection device that can generate current modifications based on the characteristics of the buried structure and / or the magnetic response of the structure.

[0014] Another problem that the present invention aims to solve is to associate in real time the generation of current according to the conditions of measurement of the sensors in order to optimize the data from the measurements of the sensors and consequently to improve the localization of structures and / or the diagnosis of the state of the structures.

[0015] Another problem that the present invention aims to solve is to propose a simple injection device to implement, adapted to field conditions and capable of generating current voltages up to 150 V at precise and adjustable frequencies.

[0016] Summary of the present invention

[0017] The present invention relates to a device for injecting a current into a magnetic and / or metallic structure to generate a signal measurable by magnetometric sensors.

[0018] According to the invention, the current injection device comprises:

[0019] - input connection means to a power supply,

[0020] - means for connecting at the output to electrical connection points of said structure,

[0021] - a stage for converting the voltage supplied by the power supply into current comprising an inverter and processing means for generating a DC output voltage at at least one determined frequency,

[0022] - a filtering stage for controlling the envelope of the injected current at the level of the structure allowing a response from the structure to be obtained that can be measured by magnetometric sensors.

[0023] The present invention further relates to a mapping device for monitoring the condition and / or geolocating a buried, semi-buried, or submerged structure made of a metallic or magnetic material. The mapping device according to the invention comprises a current injection device, a vector equipped with magnetometric and position sensors, said injection device, and said vector comprising communication and control means for modifying the current to be injected based on data transmitted by the vector to the current injection device.

[0024] Definitions

[0025] According to the present invention, the expression magnetic or metallic material, in this application, refers to any type of conductive material generating a magnetic field after the injection of a current, and in particular includes ferromagnetic materials.

[0026] According to the present invention, the term vector in this application refers to a device enabling the support and movement of sensors; it may include, but is not limited to, a motorized trolley or an aerial drone equipped with a sensor support ramp. Brief description of the figures

[0027] Other features and advantages of the present invention will become apparent from the description of the particular and non-limiting embodiments of the present invention below, with reference to the attached Figures 1 to 4, in which:

[0028] [Fig-1] schematically illustrates an injection device according to a first mode of a realization conforming to the invention.

[0029] [Fig.2] represents an example of an electronic diagram of the first filtering according to the invention,

[0030] [Fig.3] schematically illustrates an example of an injection device in which The conversion stage according to the invention is detailed,

[0031] [Fig.4] represents a schematic example of the embodiment of the device mapping according to the invention.

[0032] Description of examples of implementation

[0033] Figure 1 illustrates an injection device according to a first embodiment. More specifically, the injection device schematically comprises means for connecting the input to a power supply; these means are integrated into the "power supply input" block of Figure 1.

[0034] These connection means may be made in a standard manner to allow connection to a single-phase power source preferably between 115 and 230 V for frequencies of 47 to 63 Hz.

[0035] The injection device further comprises a filtering stage. This filtering stage is implemented using two filters, the first of which is located in the "filtering 1" block between the "power input" block and the "inverter" block. This first filter includes at least one capacitor to limit variations in the current supply and to regulate the output power.

[0036] Referring this time to [Fig.2], we see an example of an electrical diagram for the realization of this first filter.

[0037] The function of this first filter is to filter the signal at the output of the "power input" block. It limits variations in the power supply to provide a perfectly stable bus. It should be noted that this stable bus is necessary for the specific application of the present invention, namely the injection of a current into a structure to allow the study of the structure's magnetic response.

[0038] Without this first filter, the bus would exhibit significant variations, leading to significant variations in the envelope of the current injected into the structure. However, the sensors used for magnetometry rely on the structure's response, which depends on this envelope.

[0039] In the absence of a stable bus, the current injected into the structure is not sufficiently stable for the magnetometry sensor measurements to be usable. In particular, in order to perform usable measurements, the applicant determined, based on the accuracy required by the algorithms, on the order of IpT, and the sensor dynamics, on the order of 250pT, that the variation of the maximum permissible envelope was 0.2%.

[0040] This first filter also makes it possible to provide a peak power greater than the power supplied at the output of the "power input" block; this characteristic is particularly interesting because the instantaneous power that must be injected into the structures to obtain an effect measurable by the sensors is greater than that obtained by conventional electrical networks such as 230V at 50Hz or 115V at 60Hz or by power supplies whose other performance (weight, dimensions) is compatible with the application.

[0041] This feature makes it possible to deliver the large power required, and in particular greater than 2000 W, on large structures or those with significant electrical losses.

[0042] To this end, as shown in [Fig. 2], the first filter is a DC filter comprising a set of capacitors that allows both control of the variation in the output voltage and the generation of power exceeding that supplied by the mains. This first filter filters the 216V bus output of the UHP-1500HV-230 power supply. In this example, it comprises four capacitors with capacitances between 350 and 500 pF, and preferably 390 pF (1.56 mF). However, other configurations with up to 10 capacitors are possible, with capacitances ranging from 100 to 500 pF. This assembly, for an output signal at 10 Hz for 100Vrms and 100Arms, can generate, at its peak, 14.2 A peak, or 2016 W, and therefore more than the power supply can provide.

[0043] The output power in a conduit representing a load of 10Q is as follows:

[0044] Pinsk, max = Vrms * Irms * 2 = 100 * 10 * 2

[0045] Pinst max = 2000 W

[0046] This capacitor assembly also makes it possible to limit the variations in the amplitude of the output signal to 0.2%.

[0047] As shown in [Fig. 1], the output of the "filtering 1" block includes the "inverter" and "microcontroller" blocks

[0048] Referring this time to [Fig.3] we see a more detailed example of the inverter and the microcontroller which respectively constitute the stage for converting the voltage supplied by the power supply into current and the processing means for generating a DC output voltage according to at least one determined frequency.

[0049] As shown in [Fig. 3], the inverter is of the Pure Sin type. The power section is equipped with an H-bridge, the principle of which is to connect the output to the 216V bus for a fraction of the time. Depending on the switching speed, the inverter can generate an output voltage that is a fraction of 216V. By varying this average value according to a sinusoidal law, a signal is produced whose fundamental frequency is at the desired output frequency and whose modulation is much higher, around 30 kHz.

[0050] The logic section consists of a microcontroller, a 3.3V power supply stage powered by the auxiliary output of the main power supply, and a sensor temperature and connectors to other system boards. Its ground is connected to earth to limit electromagnetic emissions. The two parts are electrically isolated, and a digital isolator ensures one-way communication.

[0051] Depending on the application, the conversion stage may provide one or more output frequencies. The structure's response to current injection at multiple frequencies may make sensor measurements more effective, particularly if one of the frequencies induces a response in a frequency disturbed by the environment.

[0052] To enable the generation of multiple frequencies, the electronic board of the conversion stage includes an 80 MHz clock and a temperature-compensated crystal that limits cycle-to-cycle variations. The processing means use the clock to generate different fundamental frequencies at the converter output.

[0053] The input signal of the second filter can thus have several fundamental frequencies lower than the filter frequency (1000Hz) generated by the switching in the conversion stage.

[0054] Referring again to [Fig. 1], it can be seen that the injection device further comprises an "interface" block and a "transmitter / receiver" block

[0055] The "interface" block conventionally includes means of control for the operator such as a keyboard and / or a screen.

[0056] The "transmitter / receiver" block includes means for data exchange between the injection device and the magnetometry sensors carried by the vectors. It is important to note that in a first embodiment, the injection device operates without communicating with the sensors; the various modifications to the injected current, for example, of frequency or amplitude, are carried out by the operator, possibly after collecting and analyzing the sensor data or by following a routine.

[0057] In this first embodiment, these means of communication are therefore optional and thus the injection device may not include a “transmitter / receiver” block.

[0058] In a second embodiment, the injection device as shown in [Fig. 1] includes means for transmitting / receiving with the sensors of a vehicle. This embodiment is particularly advantageous since it allows various parameters of the injected current to be modified according to data from the vehicle's sensors.

[0059] Referring to [Fig.4], we see schematically represented an example of the realization of a mapping device 1. This mapping device 1 can be used for the condition control and / or geolocation of a buried 2, semi-buried or submerged structure comprising a metallic or magnetic material.

[0060] This mapping device 1 comprises an injection device 3 and at least one vector 4 equipped with magnetometric sensors 5 and position sensors 6. The injection device 3 and said vector 4 include communication and control means (not shown in the attached [Fig. 4]). According to an advantageous feature of the invention, the data transmitted to the injection device 3 allows instructions to be sent by the processing means to modify the current to be injected into the structure 2.

[0061] For example, when the data show too weak a response of the structure to the current injection, the instruction of the processing means may be to change the frequency and / or increase the intensity of the current.

[0062] By way of example, position data can also be used to start or stop current injection, in particular depending on the presence of vector 4 on the area to be inspected or outside of this area.

[0063] As mentioned above, the communication and control means associated with the processing means allow for the modification of the frequency and / or intensity parameters of the injected current. It is also possible for the communication and control means to transmit information to the operator via the interface, enabling them to adjust the parameters of the injection device 3.

[0064] Conversely, in a third embodiment, combinable with the two other embodiments previously described, the communication and control means allow the transmission of navigation commands from the injection device 3 to the vector 4.

[0065] Referring again to [Fig. 1], it can be seen that the injection device also includes a "stabilizer" block. According to an advantageous feature of the invention, the connection means, the filtering stage, and the conversion stage are arranged in a case incorporating mechanical stabilization means. These mechanical stabilization means protect the sensitive electronic components of the injection device. Advantageously, these mechanical stabilization means include foam and shock absorbers for stabilizing the electronic components of said control device in terms of temperature and / or humidity and / or position. The stabilization means also include a waterproof case for housing all the components of the current injection device.

[0066] According to the invention, the filtering means stage comprises a second filtering stage located at the "filtering 2" block shown in [Fig. 1]. The second filtering stage is obtained by a frequency filter allowing the selection of at least one fundamental harmonic.

[0067] Advantageously, the frequency filter is a differential low-pass LC filter, the inductances of the differential filter smoothing the current and the capacitor limiting voltage shocks.

[0068] Advantageously, it is also provided that the second filtering allows at least two fundamental frequencies to be selected simultaneously and / or alternately.

[0069] Referring to [Fig. 1], it can be seen that the injection device further comprises an "output connection" block. This "output connection" block contains the means for connecting the output to electrical connection points of the structure.

[0070] These output connection means comprise a first output connectable to earth, and a second to an underground conduit. The load is similar to a complex impedance in series with a battery connected to the galvanic contact between the steel and the earth. The latter creates a voltage of approximately 2V across its terminals and an impedance of 1Q to 15Q depending on the type of soil and conduit.

[0071] The injection device as described therefore makes it possible to overcome the disadvantages of the current generators of the prior art by offering characteristics allowing precise control of the parameters of current injected into the structure and, in an advantageous variant, means of control according to the measurements made by the sensors of the vehicle.

[0072] Of course, other features within the reach of a person skilled in the art could also have been considered without going out of the scope of the invention as defined in the following claims.

Claims

Demands

1. Device for injecting a current into a magnetic and / or metallic structure to generate a signal measurable by magnetometric sensors, characterized in that it comprises: - input connection means to a power supply, - output connection means to electrical connection points of said structure, - a voltage conversion stage supplied by the power supply comprising an inverter and processing means for generating a DC output voltage at least at one determined frequency, - a filtering stage for controlling the envelope of the current injected into the structure allowing to obtain a response of the structure measurable by magnetometric sensors.

2. Current injection device according to the preceding claim in which the filtering means comprise a first filtering, disposed between the power supply and the conversion stage, said first filtering comprising at least one capacitor enabling the limitation of variations in the power supply and the regulation of the output power.

3. Current injection device according to the preceding claim in which the first filtering comprises a series of capacitors of 1 to 10 capacitors with capacitances of 100 to 500pF allowing to limit the variations of the amplitude of the output signal to 0.2%.

4. Current injection device according to the preceding claim in which the first filtering comprises a series of 4 capacitors with capacitances of 350 to 500pF allowing the amplitude variations of the output signal to be limited to 0.2%.

5. Current injection device according to any one of claims 2 to 4 in which the filtering means comprise a second filter comprising a frequency filter enabling the selection of at least one fundamental harmonic.

6. Current injection device according to claim 5, wherein the frequency filter is an LC low-pass differential filter, the Inductances of the differential filter smoothing the current and the capacitor limiting voltage surges.

7. Current injection device according to any one of claims 4 to 6 wherein the second filtering allows selection of at least two fundamental frequencies simultaneously and / or alternately.

8. Current injection device according to any one of the preceding claims characterized in that the connection means, the filtering stage and the conversion stage are arranged in a case incorporating mechanical stabilization means comprising foam and shock absorbers enabling the electronic components of said control device to be stabilized in temperature and / or humidity and / or position.

9. Mapping device for the condition control and / or geolocation of a buried, semi-buried or submerged structure comprising a metallic or magnetic material comprising an injection device according to any one of claims 1 to 8, a vector equipped with magnetometric sensors and position sensors, said injection device and said vehicle comprising communication and control means for modifying the current to be injected according to data transmitted by the vehicle to the control device.

10. Mapping device according to the preceding claim 9 in which the communication and control means associated with the processing means allow the modification of the parameters in frequency and / or intensity of the current to be injected.

11. Mapping device according to any one of claims 9 and 10 wherein the communication and control means enable the transmission of navigation commands from the injection device to the vehicle.

Images