• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
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    • 专利摘要:
    Method for detecting non-free faults in a transmission line (L) comprising the steps of: - Acquiring (301) a temporal reflectogram, - Calculating (302) the integral (INT) of the time reflectogram, - Selecting (303), in the integral (INT), three samples P1, P2, P3, - Calculate (304) a first distance equal to the difference in absolute value between the value of the second sample P2 and the value of the first sample P1 or the third sample P3 Calculating (305) a second distance equal to the difference in absolute value between the value of the first sample P1 and the third sample P3; - making a first comparison (307) of the first distance at the second distance weighted by a coefficient of β weighting, - Deduce from the result of the first comparison (307) information on the existence of a non-straightforward defect.
    公开号:FR3048511A1
    申请号:FR1651702
    申请日:2016-03-01
    公开日:2017-09-08
    发明作者:Luca Incarbone；Roman Miguel Gallego
    申请人:Commissariat a lEnergie Atomique CEA；Commissariat a lEnergie Atomique et aux Energies Alternatives CEA；
    IPC主号:
    专利说明:

    The invention relates to the field of wired diagnostic systems based on the principle of reflectometry. It relates to a method for detecting non-free faults in a cable, based on the exploitation of the integral of a reflectogram.
    Cables are ubiquitous in all electrical systems, for powering or transmitting information. These cables are subject to the same constraints as the systems they connect and may be subject to failures. It is therefore necessary to be able to analyze their state and to provide information on the detection of faults, but also their location and their type, in order to help maintenance. The usual reflectometry methods allow this type of test.
    OTDR methods use a principle similar to that of radar: an electrical signal, the probe signal or reference signal, which is usually high frequency or broadband, is injected at one or more points of the cable to be tested. The signal propagates in the cable or network and returns some of its energy when it encounters an electrical discontinuity. An electrical discontinuity may result, for example, from a connection, the end of the cable or a defect or more generally a break in the conditions of propagation of the signal in the cable. It most often results from a fault that locally modifies the characteristic impedance of the cable by causing a discontinuity in its linear parameters. The analysis of the signals returned to the injection point makes it possible to deduce information on the presence and the location of these discontinuities, thus possible defects. An analysis in the time or frequency domain is usually performed. These methods are designated by the acronyms TDR from the English expression "Time Domain Reflectometry" and FDR from the English expression "Frequency Domain Reflectometry". The invention falls within the scope of OTDR methods for wireline diagnostics and applies to any type of electrical cable, in particular power transmission cables or communication cables, in fixed or mobile installations . The cables concerned may be coaxial, two-wire, parallel lines, twisted pairs or other provided that it is possible to inject a reflectometry signal at a point of the cable and measure its reflection at the same point or another point .
    The known time domain reflectometry methods are particularly suitable for detecting faults in a cable, such as a short circuit or an open circuit, or more generally a significant local modification of the impedance of the cable. The detection of the defect is done by measuring the amplitude of the signal reflected on this defect which is all the more important and therefore detectable, that the defect is important. Conversely, a non-straightforward defect, for example resulting from a superficial degradation of the sheath of the cable of the insulator or of the conductor, generates a peak of low amplitude on the reflected reflectometry signal and is therefore more difficult. detectable by conventional time methods. More generally, a non-straightforward defect can be caused by friction, pinching or even a corrosion phenomenon that affects the cable sheath, the insulator or the conductor.
    Detecting and locating a non-straightforward defect on a cable is an important problem for the industrial world since a defect generally appears first as a superficial defect but may, over time, evolve into a more impacting defect. For this reason in particular, it is useful to be able to detect the appearance of a defect as soon as it appears and at a stage where its impact is superficial in order to anticipate its evolution into a larger defect.
    The small amplitude of the reflections associated with the passage of the signal through a non-straightforward defect also causes a potential problem of false detections. Indeed, it may be difficult to discriminate a peak of small amplitude in a reflectogram that may result either from a fault on the cable, or a measurement noise. Thus, false positives may appear which correspond not to defects but which result from measurement noise or inhomogeneities of the cable. The state of the art comprises several methods for detecting non-straightforward defects based on the principle of reflectometry.
    The Applicant's French patent application published under the number FR2981752 proposes a post-processing method of a reflectogram based on the Wigner-Ville mathematical transform. The method consists of a time-frequency analysis of the reflectogram in order to accentuate the components corresponding to the desired defects. A disadvantage of this method is its significant complexity for embedded equipment
    The Applicant's French patent application published under the number FR3006769 proposes a different approach based on a signal processing measured in the frequency domain in order to estimate certain characteristic parameters of the propagation of the signal in the cable. The detection of non-free faults is done by analyzing the estimated parameters.
    Applicant's French patent applications filed respectively under the numbers FR1459402 and FR1554632 are also known. The first proposes a method of self-adaptive correlation between the reflected signal and the injected signal while the second focuses on a search for zero crossings of the reflectogram and a comparison of the energy of the signal calculated on either side of the transition to zero. We can also mention the so-called subtractive correlation method described in the document "Improvement methods for cable diagnosis by reflectometry", Lola El Sahmarany, University Blaise Pascal -Clermont-Ferrand II, 2013.
    The latter methods have improved results for the detection of unprepared defects but can, however, generate a significant number of false detections or false positives due to the difficulty of discriminating low amplitude peaks associated with defects and those associated with noise. measurement or native inhomogeneities of the cable. The invention proposes a new method of detecting non-free defects based on a post-treatment applied to the integral of the measured reflectogram. The invention has the advantage of limiting false detections and being difficult to implement, thus facilitating its implementation in an embedded device. The subject of the invention is thus a method for detecting non-free faults in a transmission line comprising the following steps: - Acquire a measurement signal, called a temporal reflectogram, characteristic of the reflection of a reference signal previously injected into the line, - Calculate the integral of the time reflectogram, - Select, among the samples of the integral of the temporal reflectogram, a first sample Pi, a second sample P2, delayed by a first delay ki with respect to the first sample Pi and a third sample P3, delayed by a second delay k2 with respect to the second sample P2, - calculating a first distance equal to the difference in absolute value between the value of the second sample P2 and the value of any one of the first sample Pi or of the third sample P3, - Calculate a second distance equal to the difference in absolute value between the of the first sample Pi and the third sample P3, - To make a first comparison of the first distance at the second distance weighted by a weighting coefficient β, - To deduce from the result of the first comparison information on the existence of a defect not frank at a cable position corresponding to the temporal abscissa of the second sample P2.
    According to a particular embodiment, the method according to the invention further comprises the following steps: - Performing a second comparison of the first distance with a detection threshold a, - Deriving from the result of the first comparison and the second comparison a information on the existence of a defect not frank in a position of the cable corresponding to the temporal abscissa of the second sample P2.
    According to one particular aspect of the invention, the first delay k i and the second delay k 2 are determined at least as a function of the width of the first mismatch peak measured on the temporal reflectogram.
    According to one particular aspect of the invention, the method is iterated by varying the first sample Pi over a plurality of samples of the integral of the temporal reflectogram while keeping the values of the first delay ki and the second delay k2 fixed during the iterations.
    According to a particular aspect of the invention, the first delay ki is equal to the second delay k2.
    According to a particular aspect of the invention, the detection threshold a is configured at least as a function of a parameter among the signal-to-noise ratio on the first signal r (t) and the severity of the non-objective defect referred to.
    According to one particular aspect of the invention, the value of the weighting coefficient β is taken in the interval [3; 9].
    According to a particular aspect of the invention, the temporal reflectogram is replaced by the cross correlation between the first measurement signal r (t) and the reference signal s (t).
    According to a particular embodiment, the method according to the invention comprises a diagnostic step consisting in concluding that there is a non-straightforward defect at a cable position corresponding to the temporal abscissa of the second sample P2 if the first distance is greater than the detection limit a and if the first distance is greater than the second distance weighted by the weighting coefficient β.
    According to a particular embodiment, the method according to the invention comprises a diagnostic step consisting in concluding that there is no non-straightforward defect at a cable position corresponding to the temporal abscissa of the second sample P2 if the first distance is below the detection threshold a and if the first distance is less than the second distance weighted by the weighting coefficient β. The invention also relates to a device for detecting non-straightforward faults in a cable comprising a measuring device, at a point of the cable, a signal retro-propagated in the cable and a computer configured to perform the detection method. non-straightforward faults in a cable according to the invention. The subject of the invention is also a reflectometry system comprising an injection device, at a point of the cable, of a reference signal and a device for detecting non-free faults in a cable according to the invention. The invention also relates to a computer program comprising instructions for executing the method for detecting unprepared faults in a cable according to the invention, when the program is executed by a processor. The subject of the invention is also a recording medium readable by a processor on which is recorded a program comprising instructions for executing the method for detecting unfair defects in a cable according to the invention, when the program is executed. by a processor. Other characteristics and advantages of the present invention will appear better on reading the description which follows in relation to the appended drawings which represent: FIG. 1, a diagram illustrating the known principle of time domain reflectometry and its application to the detection of a non-straightforward defect; FIG. 2, an example of a reflectogram illustrating the appearance of the signature of a non-straightforward defect; FIG. 3, a flowchart detailing the stages of implementation of the method according to the invention; - Figures 4a, 4b, 4c several diagrams illustrating certain steps of the method according to the invention, - Figure 5, a diagram of an embodiment of a non-free-flaw detection device according to the invention.
    A non-straightforward defect generally introduces a local modification of the electrical characteristics of a transmission line, for example a cable. The physical degradation, even superficial, of the line causes in particular a local modification of the characteristic impedance of the cable, which causes a change in the reflection coefficient at the location of the fault.
    The term non-straightforward defect here refers to any fault superficially impacting a cable so as to generate a variation of the characteristic impedance locally. In particular, such defects include scuffing or wear of the sheath, the dielectric but also the beginning of the degradation of the metallic conductor, the compression of a cable, friction or corrosion. These degradations can, at first sight, seem benign and without significant repercussions for the system. However, if nothing is done, the mechanical, environmental or aging of the cable, will evolve a defect not franc frank defect, whose consequences, both economic and material, can be considerable. Detecting incipient defects allows better maintenance management and therefore a reduction in repair costs.
    FIG. 1 schematizes the operating principle of a diagnostic method using reflectometry applied to a transmission line L presenting a non-free defect DNF.
    A reference signal S is injected into the transmission line at a point P. The reflected signal R is measured at the same point P (or at another point of the line). This signal propagates in the line and encounters, during its propagation, a first impedance discontinuity at the input of non-free DNF defect. The signal is reflected on this discontinuity with a reflection coefficient. If the characteristic impedance 2 ^ 2 in the area of the non-free defect DNF is less than the characteristic impedance before the occurrence of the fault, then the reflection coefficient is negative and results in a negative amplitude peak in the signal In the opposite case, the reflection coefficient is positive and results in a positive amplitude peak in the reflected signal R.
    The transmitted part T of the incident signal S continues to propagate in the line and then encounters a second impedance discontinuity creating a second reflection of the incident signal with a reflection coefficient Γ2 of opposite sign to the first reflection coefficient Γ ^. If <0 then Γ2> 0. If Γι> 0 then Γ2 <0.
    Thus, by observing the reflected signal R, the signature of the non-free defect DNF is characterized by two successive peaks of inverted signs as shown in FIG.
    FIG. 2 represents a temporal reflectogram which corresponds either directly to the measurement of the reflected signal R or to the cross-correlation between the reflected signal R and the signal injected into the cable S.
    In the case where the injected reference signal is a time pulse, the reflectogram may correspond directly to the measurement of the reflected signal R. In the case where the injected reference signal is a more complex signal, then the reflectogram is obtained by inter-correlating the reflected signal R and the injected signal S.
    FIG. 2 shows two reflectograms 201, 202 corresponding to two different pulse durations for the signal injected into the cable. The curve 201 corresponds to a pulse duration 2.ΔΤ much greater than the transit time, by the signal, of the non-free DNF defect. The length of the fault being denoted Ld, this duration is worth Ld / V, with V the speed of propagation of the signal in the cable. The curve 202 corresponds to a pulse duration 2.ΔΤ much less than the transit time, by the signal, of the non-free DNF defect.
    In both cases, the signature 203 of the non-frank defect in the reflectogram is always composed of the succession of a first peak and a second peak whose signs are reversed. This property is exploited by the invention to improve the detection of such defects.
    The distance between the two peaks represents the length of the non-frank defect and their amplitude represents the severity of the non-frank defect. Indeed, the greater the variation in the characteristic impedance, the greater the amplitude of the signature of the non-frank defect in the reflectogram is also important.
    Figure 3 details the steps of implementation of the method of detecting non-free defects according to the invention.
    The method according to the invention is applied to a temporal reflectogram which reflects the reflections of a reference signal injected into the cable, on the impedance discontinuities it encounters during its propagation. The nature of the reflectogram depends on the type of reference signal envisaged. In general, whatever the form of the signal, the reflectogram can be obtained from a measurement of the signal propagated in the cable and then an inter-correlation of this measurement with the reference signal which has been injected into the signal. cable. In the case where the reference signal used is a time pulse, for example a Gaussian-shaped pulse, the step of inter-correlation of the measurement with the reference signal is not necessary.
    Thus, the method begins with the acquisition or construction 301 of a temporal reflectogram from at least one measurement of a signal propagated in the cable.
    An example temporal reflectogram is shown in Figure 4a. This reflectogram comprises a characteristic signature of a non-straightforward defect comprising a first peak of positive sign followed by a second peak of opposite negative sign and amplitude substantially identical to the first peak.
    In an optional step, not shown in FIG. 4a, the difference between the measured time reflectogram and a temporal reflectogram measured at a previous instant, for example at the time of setting up the cable, is calculated in order to eliminate the inhomogeneities present in the cable from its conception. This step also makes it possible to monitor the evolution of defects impacting the cable by performing a differential analysis.
    The method continues in a second step 302 of calculating the integral INT reflectectogram. The integral is computed numerically, for example by calculating the sum of the reflectogram samples between the instant 0 and the current instant t. An exemplary result of the computation of the integral INT of the reflectogram of FIG. 4a is represented in FIG. 4b. Note that after calculating the integral, the two peaks of inverted signs characteristic of a non-straightforward defect are converted into a single peak of double duration with respect to the duration of each of the two peaks of the signature of the defect in the reflectogram. The invention aims to exploit the characteristic form of the signature of a non-frank defect, after calculating the integral of the reflectogram, by searching this form in order to locate a non-frank defect with precision.
    For this, the following steps 303, 304, 305, 306, 307 can be iterated for all the samples of the integral INT of the reflectogram in order to find the presence of a non-straightforward defect along the entire length of the cable. Alternatively, these steps can be performed only for a given time interval of the integral INT of the reflectogram, for example an interval corresponding to a zone of the cable in which a fault has been pre-localized. Step 303 consists in selecting three samples P1, P2, P3 of the integral INT, respectively spaced by a duration k1 and a duration k2 as illustrated in FIG. 4c. The durations k1 and k2 are parameters of the invention and are fixed once and for all for the treatment of the entire reflectogram. Thus, the three points P1, P2, P3 can traverse the integral curve INT of the reflectogram, an object of the invention being to detect the configurations for which the second point P2 coincides with the vertex of the peak of the signature of a defect, while the first point P1 and the last point P3 respectively coincide with the beginning and the end of the peak. This configuration is shown in Figure 4c. It should be noted that the amplitude peak characteristic of the presence of a non-frank defect in the integral INT of the reflectogram may also be of negative sign (opposite configuration to that of Figure 4c).
    The durations k1 and k2 are determined so that the delay between the last point P3 and the first point P1 is substantially equal to the duration of the signature of a defect that one wishes to detect, in the integral of the reflectogram. .
    In the case where the reference signal used is a time pulse, the durations k1 and k2 are determined as a function of the duration of the pulse of the reference signal injected into the cable or the frequency of this signal. In this case, the total duration k1 + k2 can be chosen, for example, equal to twice the duration of the pulse of the reference signal injected into the cable or the pulse associated with the first mismatch peak on the d-point. injection of the cable into the reflectogram.
    In the more general case where the reference signal used has any shape, the total duration k1 + k2 can be determined by measuring the width of the first mismatch peak in the reflectogram obtained after inter-correlation between the reference signal and the signal. thoughtful measured.
    One possible embodiment of the invention is to choose k1 = k2 to search symmetrically shaped amplitude peaks.
    In an alternative embodiment, the duration k2 may be taken equal to a value greater than that of the duration k1 in order to take into account the dispersion phenomena, which occur especially at high frequencies, to detect defects located at a great distance injection point. Indeed, the symmetry of the double pulse, characteristic of the signature of a non-straightforward defect in a reflectogram, can be distorted because of the potential variability of the speed of propagation of the signal as a function of frequency.
    In a step 304, a first difference in absolute value is calculated between the second sample P2 and the first sample P1. Alternatively, the first sample P1 can be replaced by the third sample P3.
    In a step 305, a second difference in absolute value between the third sample P3 and the first sample P1 is also calculated.
    The process continues with two comparison steps 306,307.
    The first step 306 consists in comparing the first difference calculated in step 304 with a configurable detection threshold a. This test makes it possible to discriminate a non-straightforward defect of a simple noise-related measurement artefact. The detection threshold a depends on the severity of the fault to be detected and the signal-to-noise ratio on the measurement. The first difference | P2-P1 | (or | P2-P3 |) gives information on the amplitude of the characteristic peak of a non-frank fault in the INT integral of the reflectogram.
    If the first difference is less than the detection threshold a, the method concludes that there is no fault at the point of the cable corresponding to the time abscissa of the second selected point P2. It will be recalled here that there is a direct correspondence between the temporal abscissae of the points of a reflectogram (or the integral of a reflectogram) and the distance between the injection point of the reference signal and a point of the cable. The two pieces of information are linked by the relation d = Vt where V is the speed of propagation of the signal in the cable, d is a distance between the injection point and a point of the cable and t is the temporal abscissa of a point. the reflectogram. Conversely, if the first difference is greater than or equal to the detection threshold a, then the process proceeds to a second comparison step 307. In this step 307, comparing the first difference calculated in step 304 with the second difference calculated in step 305 and multiplied by a weighting coefficient β. This second test makes it possible to detect the shape of the signature of a non-frank fault in the integral INT of the reflectogram. The weighting coefficient β depends on the shape of the characteristic pulse of a non-frank defect in the integral INT of the reflectogram. The value of this weighting coefficient is experimentally fixed. A preferred value of this coefficient, obtained experimentally, is in the range [3; 9d. The comparison of the first difference | P2-P1 | (or | P2-P3 |) with the second difference | P3-P11 weighted by a coefficient β makes it possible to characterize the shape of the pulse.
    If the first difference is smaller than the second difference weighted by the coefficient β, then the method concludes that there is no fault at the point of the cable corresponding to the time abscissa of the second selected point P2. On the other hand, if the first difference is greater than or equal to the second difference weighted by the coefficient β, then the method concludes that there is a non-straightforward defect at the point of the cable corresponding to the temporal abscissa of the second point P2. selected.
    The test steps 306 and 307 can be performed in the order indicated above or in the reverse order, that is to say by first applying the test 307 with respect to the coefficient β and then the test 306 associated with the detection threshold a.
    According to a particular embodiment of the invention, the first test step 306 can be made optional, the method according to the invention then comprising only the test step 307. The invention has the advantage of being little complex to implement because it only requires simple calculations (addition, subtraction and comparison). It can thus be easily embedded in a wired portable diagnostic equipment. In addition, the invention makes it possible to precisely locate a non-straightforward defect by searching for the peak of the amplitude peak characteristic of the signature of such a defect in the domain of the integral of the reflectogram. The invention can be applied to any type of compatible signals of a reflectometry diagnosis as well as any type of cable for which the problem of detection of superficial defects exists.
    FIG. 5 schematizes, on a block diagram, an example of a reflectometry system capable of implementing the method according to the invention.
    A reflectometry system, or reflectometer, comprises at least one signal generator GS, for generating a test signal s and injecting it into the cable to be analyzed CA which has a non-free defect DNF, a measuring equipment Ml for measuring the signal. reflected signal in the AC cable and an integrated circuit type electronic component MC, such as a programmable logic circuit, for example of the FPGA type or a microcontroller, for example a digital signal processor, which receives the measurement of the reflected signal r (t) and is configured to perform the method according to the invention in order to detect and locate one or more non-free defects. The electronic component MC may also comprise both an integrated circuit, for example to carry out the acquisition of the reflected signal, and a microcontroller for performing the processing steps required by the invention.
    According to a particular embodiment, the test signal can also be supplied to the MC component when the processing operations require knowledge of the injected signal, especially when these include a step of intercorrelation between the test signal s and the signal. reflected signal r. The injection of the signal into the cable and the measurement of the reflected signal can be carried out by one and the same component but also by two distinct components, especially when the injection point and the measuring point are dissociated.
    The system described in FIG. 5 can be implemented by an electronic card on which the various components are arranged. The card can be connected to the cable by a coupler.
    In addition, a processing unit, such as a computer, personal digital assistant or other equivalent electronic or computer device can be used to control the reflectometry device and display the results of the calculations performed by the component MC on a human-machine interface, in particularly the information for detecting and locating defects on the cable.
    The method according to the invention can be implemented on the MC component from hardware and / or software elements.
    The method according to the invention can be implemented directly by an embedded processor or in a specific device. The processor may be a generic processor, a specific processor, an application-specific integrated circuit (also known as ASIC for "Application-Specific Integrated Circuit") or a network of programmable gates in situ (also known under the English name of FPGA for "Field-Programmable Gaste Array"). The device according to the invention can use one or more dedicated electronic circuits or a general purpose circuit. The technique of the invention can be realized on a reprogrammable calculation machine (a processor or a microcontroller for example) executing a program comprising a sequence of instructions, or on a dedicated calculation machine (for example a set of logic gates). as an FPGA or an ASIC, or any other hardware module).
    The method according to the invention can also be implemented exclusively as a computer program, the method then being applied to a measurement of reflectometry r previously acquired using a conventional reflectometry device. In such a case, the invention can be implemented as a computer program comprising instructions for its execution. The computer program can be recorded on a processor-readable recording medium.
    The reference to a computer program that, when executed, performs any of the functions described above, is not limited to an application program running on a single host computer. On the contrary, the terms computer program and software are used herein in a general sense to refer to any type of computer code (for example, application software, firmware, microcode, or any other form of computer code). computer instruction) that can be used to program one or more processors to implement aspects of the techniques described herein. The means or computing resources can be distributed in particular ("Cloud computing"), possibly using peer-to-peer technologies. The software code may be executed on any suitable processor (for example, a microprocessor) or a processor core or set of processors, whether provided in a single computing device or distributed among a plurality of computing devices (eg example as possibly accessible in the environment of the device). The executable code of each program enabling the programmable device to implement the processes according to the invention can be stored, for example, in the hard disk or in read-only memory. In general, the program or programs may be loaded into one of the storage means of the device before being executed. The central unit can control and direct the execution of instructions or portions of software code of the program or programs according to the invention, instructions that are stored in the hard disk or in the ROM or in the other storage elements mentioned above.
    权利要求:
    Claims (14)
    [1" id="c-fr-0001]
    1. A method for detecting unraveled defects in a transmission line (L) comprising the following steps: - Acquiring (301) a measurement signal (R), called a time-domain reflectogram, characteristic of the reflection of a reference signal ( S) previously injected into the line (L), - Calculate (302) the integral (INT) of the temporal reflectogram, - Select (303), from the samples of the integral (INT) of the temporal reflectogram, a first sample Pi a second sample P2, delayed by a first delay ki with respect to the first sample Pi and a third sample P3, delayed by a second delay k2 with respect to the second sample P2, - calculating (304) a first distance equal to the difference in absolute value between the value of the second sample P2 and the value of any one of the first sample Pi or the third sample P3, - calculate (305) a second distance equal to the difference in absolute value between the value of the first sample Pi and the third sample P3, - making a first comparison (307) of the first distance with the second distance weighted by a weighting coefficient β, - deducing from the result of the first comparison (307) information on the existence of a non-straightforward defect at a position of the cable corresponding to the temporal abscissa of the second sample P2.
    [2" id="c-fr-0002]
    2. A method for detecting unfilled faults in a cable according to claim 1, further comprising the following steps: - performing a second comparison (306) of the first distance with a detection threshold a; - deducing from the result of the first comparison (307) and the second comparison (306) information on the existence of a defect not frank at a position of the cable corresponding to the temporal abscissa of the second sample P2.
    [3" id="c-fr-0003]
    3. A method for detecting unfilled faults in a cable according to one of the preceding claims wherein the first delay ki and the second delay k2 are determined at least as a function of the width of the first mismatch peak measured on the time reflectogram.
    [4" id="c-fr-0004]
    4. A method for detecting unfilled faults in a cable according to one of the preceding claims wherein iterates the process by varying the first sample Pi on a plurality of samples of the integral (INT) of the time reflectogram retaining the values of the first delay ki and the second delay k2 fixed during the iterations.
    [5" id="c-fr-0005]
    5. Method for detecting unfilled faults in a cable according to one of the preceding claims wherein the first delay ki is equal to the second delay k2.
    [6" id="c-fr-0006]
    6. Method for detecting non-free faults in a cable according to one of the preceding claims, in which the detection threshold a is configured at least as a function of a parameter among the signal-to-noise ratio on the first signal r (t). and the severity of the non-frank defect.
    [7" id="c-fr-0007]
    7. A method for detecting unfilled defects in a cable according to one of the preceding claims wherein the value of the weighting coefficient β is taken in the interval [3; 9].
    [8" id="c-fr-0008]
    8. A method for detecting unfilled faults in a cable according to one of the preceding claims wherein the time reflectogram is replaced by the cross correlation between the first measurement signal r (t) and the reference signal s (t).
    [9" id="c-fr-0009]
    9. A method for detecting unfilled faults in a cable according to one of the preceding claims comprising a diagnostic step of concluding the presence of a non-frank defect at a cable position corresponding to the temporal abscissa of the second sample. P2 if the first distance is greater than the detection threshold a and if the first distance is greater than the second distance weighted by the weighting coefficient β.
    [10" id="c-fr-0010]
    10. A method for detecting unfilled faults in a cable according to one of the preceding claims comprising a diagnostic step of concluding the absence of a defect not frank at a position of the cable corresponding to the temporal abscissa of the second. sample P2 if the first distance is less than the detection threshold a and if the first distance is less than the second distance weighted by the weighting coefficient β.
    [11" id="c-fr-0011]
    11. Device for detecting non-free faults in a cable (CA) comprising a measuring apparatus (Ml), at a point of the cable (CA), a signal propagated in the cable and a computer (MC) configured for performing the method of detecting unfilled defects in a cable according to any one of claims 1 to 10.
    [12" id="c-fr-0012]
    12. OTDR system comprising an injection device (GS), at a point of the cable, a reference signal and a device for detecting unfilled defects in a cable (CA) according to claim 11.
    [13" id="c-fr-0013]
    13. Computer program comprising instructions for performing the method of detecting unfair faults in a cable according to any one of claims 1 to 10, when the program is executed by a processor.
    [14" id="c-fr-0014]
    14. A processor-readable recording medium on which is recorded a program comprising instructions for executing the method of detecting unfilled faults in a cable according to any one of claims 1 to 10, when the program is executed. by a processor.
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    同族专利:
    公开号 | 公开日
    WO2017148753A1|2017-09-08|
    FR3048511B1|2019-07-19|
    EP3423847A1|2019-01-09|
    US20190094289A1|2019-03-28|
    US10690712B2|2020-06-23|
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    法律状态:
    2017-03-31| PLFP| Fee payment|Year of fee payment: 2 |
    2017-09-08| PLSC| Search report ready|Effective date: 20170908 |
    2018-03-29| PLFP| Fee payment|Year of fee payment: 3 |
    2020-03-31| PLFP| Fee payment|Year of fee payment: 5 |
    2021-03-30| PLFP| Fee payment|Year of fee payment: 6 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1651702|2016-03-01|
    FR1651702A|FR3048511B1|2016-03-01|2016-03-01|METHOD FOR DETECTING NON-FREE DEFECTS IN A CABLE, BASED ON THE INTEGRAL OF A REFLECTOGRAM|FR1651702A| FR3048511B1|2016-03-01|2016-03-01|METHOD FOR DETECTING NON-FREE DEFECTS IN A CABLE, BASED ON THE INTEGRAL OF A REFLECTOGRAM|
    EP17706738.6A| EP3423847A1|2016-03-01|2017-02-22|Method for detecting soft faults in a cable, which method is based on the integral of a reflectogram|
    US16/081,410| US10690712B2|2016-03-01|2017-02-22|Method for detecting soft faults in a cable, which method is based on the integral of a reflectogram|
    PCT/EP2017/053973| WO2017148753A1|2016-03-01|2017-02-22|Method for detecting soft faults in a cable, which method is based on the integral of a reflectogram|
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