• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a method for monitoring the state of health of an electric cable arranged between an emitter and a receiver, said electric cable being configured to transmit, in addition to the electric current, digital communication data according to the technology of the carrier current. line according to a multi-carrier modulation, OFDM type, said cable defining a transmission channel between said transmitter and said receiver, the method comprising the following steps implemented in a computer: successive measurements of a transfer function of a transmission channel; detecting at least one variation between the measured transfer functions, said variation being characteristic of a fault in said electric cable.
    公开号:FR3019307A1
    申请号:FR1452606
    申请日:2014-03-26
    公开日:2015-10-02
    发明作者:Thibaud Lebreton；Herve Ressencourt
    申请人:Labinal Power Systems SAS；
    IPC主号:
    专利说明:

    [0001] GENERAL TECHNICAL FIELD The invention relates to the field of monitoring the state of health of an electric cable of an aircraft with a view to detecting anomalies.
    [0002] STATE OF THE ART In an aircraft, electrical wiring is a critical element in the nominal operation of systems that are increasingly electric: its reliability greatly affects flight safety. The regulatory agencies FAA (in English, "Federal Aviation Administration") and EASA (in English, "European Aviation Safety Agency") require as such that the cabling is considered as a system and no longer as simple elements of transportation of power and signals. In addition, aeronautical systems must meet particular requirements in terms of monitoring their condition and the designer must be able to determine the consequences of any type of defects appearing in his system. A common technique for monitoring an electrical cable is a technique of visual inspection of the cable. This technique is very time consuming. In order to avoid manual intervention, a technique for monitoring the state of health of an electric cable based on reflectometry is known. This technique consists of transmitting a signal and detecting a change in impedance. OTDR not only detects but also locates faults along the electrical cable. A problem with this solution is that it only allows to detect blemishes: open circuits or short circuits. It therefore does not currently detect weak defects such as insulation wear, and therefore it does not allow to predictively alert a defect before it appears. On the other hand, it does not make it possible to locate defects in a complex harness with multiple branches. Indeed, reflectometry uses a single transceiver which is installed at the end of the line so that the surveillance is global and the location of the defect remains rather imprecise. Finally, this technique adds a complexity and a significant weight which in aeronautics is problematic, the weight / volume criteria being drastic. PRESENTATION OF THE INVENTION The invention proposes to overcome at least one of these disadvantages. For this purpose, the invention proposes a method for monitoring the state of health of an electric cable arranged between a transmitter and a receiver, said electric cable being configured to transmit, in addition to the electric current, digital communication data according to the technology. in-line carrier current according to a multi-carrier modulation, of the OFDM type, said cable defining a transmission channel between said transmitter and said receiver, the method comprising the following steps implemented in a computer: successive measurements of a transfer function of a transmission channel; detecting at least one variation between the measured transfer functions, said variation being characteristic of a fault in said electric cable. The invention is advantageously completed by the following characteristics, taken alone or in any of their technically possible combination.
    [0003] A measurement of a transfer function consists in transmitting on N carrier (s) digital estimation data and in estimating the transmission channel from these digital estimation data. The detection of at least one variation is performed over a time window of between 0 and 10 ms, in order to detect intermittent or frank defects.
    [0004] The detection of at least one variation is carried out over a time window equal to the duration of a flight, in order to detect defects characteristic of a slow degradation of said electric cable. The method includes, if a variation is detected, a cable analysis by a reflectometry technique to locate and / or confirm a fault.
    [0005] The invention also relates to a device for monitoring the state of health of an electrical cable configured to transmit, in addition to the electrical current, digital communication data according to the in-line carrier technology, the device comprising a transmitter and a receiver arranged between two ends of the cable to be monitored, the receiver comprising a computer configured to implement one of the methods above. The advantages of the invention are manifold. The use of a transmitter / receiver CPL (Line Carrier Current) to transmit and analyze signals dedicated for example to monitoring or control makes it possible to more easily overcome the problems related to branch lines. Indeed, in reflectometry, the signal reflection on the branches limits the use of technology when branches appear in the path. In addition, the invention makes it possible to pool the complex electronics necessary for the transmission of PLC data and that necessary for diagnosing the state of the cable. In the case of PLC transmission, this makes it possible not to add industrial complexity or weight / volume for the addition of the cable monitoring function. PRESENTATION OF THE FIGURES Other features, objects and advantages of the invention will emerge from the description which follows, which is purely illustrative and nonlimiting, and which should be read with reference to the appended drawings, in which: FIG. implementation of a method of monitoring the state of health of a cable according to an embodiment of the invention; FIG. 2 schematically illustrates steps of a method according to an embodiment of the invention; FIG. 3 illustrates examples of transfer functions of an OFDM transmission channel. In all the figures, similar elements bear identical references.
    [0006] DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates an electric cable C which must be monitored. To do this, a transmitter E and a receiver R are arranged respectively between two ends of the electrical cable C to be monitored.
    [0007] Such an electric cable is obviously configured to transmit electrical current but also digital communication data according to the technology of the in-line carrier current (PLC). As is known in itself, the CPL technology consists in superimposing on electric current a signal of higher frequency and low energy.
    [0008] The communication data is transported on the electrical cable C according to a multi-carrier modulation of the OFDM type (Orthogonal Frequency-Division Multiplexing). Thus, the electric cable defines a transmission channel.
    [0009] As known per se the OFDM modulation serves to distribute on the transmission channel the communication data which are digital data on a number N of subcarriers. The number N of subcarriers is typically a power of 2 and is generally N = 256, N = 512 or N = 1024. This number N of sub-carriers may, however, be arbitrarily chosen but a power of 2 is preferred to simplify the calculations for the Fourier Transform involved in the OFDM modulation. To monitor the state of health of the electric cable in order to detect a possible defect, a method of monitoring the state of health of the electrical cable C is implemented in a computer 10 disposed in the receiver R. -after, in connection with Figure 2, a method for monitoring the health status of the electrical cable C. The method consists in particular to measure MES in successive ways several transmission channel transfer functions defined by the electric cable and in detecting DET possible variations that are characteristic of one or more faults (s) of the electric cable C. The successive MES measurements of the transfer function of the transmission channel consist of the following substeps. At the level of the transmitter E, ALL is allocated a number of subcarriers N 'smaller than the number of carriers N allocated to the transmission OFDM to the estimation of the transmission channel (with NSN). In particular, these N 'carriers are allocated to the digital estimation data intended for channel estimation. These estimation data are known in advance from the transmitter E and receiver R and are known under the term "pilot data".
    [0010] In the case where the number of carriers N 'allocated to the estimation digital data is less than the number of carriers N allocated to the transmission channel, the number NN' of remaining carriers is allocated to the useful data DU of communication which are then transmitted TRANS to the receiver R on these carriers, together with the estimation data.
    [0011] Indeed, it should be noted that at the level of the receiver R to demodulate the useful data, the latter will need the transfer function of the channel in order to implement an EGA equalization process in order to obtain the demodulated useful data DD . Once this allocation has been made, it is estimated that the receiver function R is the transfer function as such. To do this, the transmitter sends known data from the receiver with a fixed amplitude. The receiver uses this data to determine / estimate the channel transfer function (ie the module and phase for each frequency). Each estimate of the channel is then MEM stored in a memory of the receiver for further processing.
    [0012] Once these MES measurements have been made, the DET detection of the variations consists in implementing the following steps. Examples of channel transfer function (dB) estimated as a function of frequency (MHz) have been illustrated in FIG. As can be seen in this figure, a channel transfer function is a function of the frequency. Thus, to detect DET a variation we will compare COMP relative to each other successive transfer functions the latter before defect be constant from one measurement to another, a defect being characterized by a deviation of the values of the function transfer.
    [0013] In the transfer function, a frank fault affects all frequencies. In general, the low frequencies attenuate less with distance and are therefore clearly visible. For non-straightforward defects, which are less visible, information processing may be necessary to improve information. The COMP comparison of the transfer functions can be done over a time window of between 0 and 10 ms (short time window), in order to detect intermittent or frank defects. Alternatively or additionally, the comparison COMP of the transfer functions can be done on a time window equal to the duration of a flight (long time window), in order to detect defects characteristic of a slow degradation of said electric cable. If it turns out that a variation is detected DET then the electric cable C has a fault otherwise the cable C has no fault. The variation of the transfer function thus detected can be either slow VAR_LENTE or fast VAR_RAPIDE.
    [0014] Such an interpretation makes it possible to characterize finely the type of defect. In the case of a slow variation VAR_LENTE the defect is characterized by an attenuation of the transfer function from strong to strong depending on the frequency. In the case of a fast variation VAR_RAPIDE is the defect is intermittent and results in an alternation in the function of transfer. Measurements made every millisecond make it possible to make comparisons along the function in order to detect the speed of variation of the transfer function. In a complementary manner, once one or more defects detected (s) can be implemented on the electric cable locating LOC step of the defect using the known technique of reflectometry. As already mentioned, the principle is based on the transmission of a signal that during an impedance change will undergo a reflection, the impedance change being characteristic of a defect. OTDR is mainly used in the time domain or the frequency domain. The difference is that in the time domain, the analysis of the reflected signals gives information on the composition of the medium unlike the frequency domain whose stationary wave analysis gives the same information. An impedance increase creates a reflection that reinforces the original impulse while a decline creates a reflection that opposes the original impulse.
    [0015] In the case where the cable is short-circuited at a time (ie a zero impedance), the wave is sent along the cable and the short-circuit will be reflected back to the source. Once the wave arrives at the source point, there is a voltage drop, so we deduce the presence of a short circuit on the cable. In addition, by knowing the speed of propagation of the signal in the medium, it is possible to determine the distance to the short circuit.
    权利要求:
    Claims (6)
    [0001]
    REVENDICATIONS1. Method for monitoring the state of health of an electric cable (C) arranged between a transmitter (E) and a receiver (R), said electric cable (C) being configured to transmit, in addition to the electric current, digital communication data according to the OFDM-type multi-carrier modulation in-line carrier technology, said cable defining a transmission channel between said transmitter and said receiver, the method comprising the following steps implemented in a computer (10): measurements (MES) successive transfer function of a channel (C) transmission; detecting (DET) at least one variation between the measured transfer functions, said variation being characteristic of a fault in said electric cable.
    [0002]
    2. The method according to claim 1, wherein a measurement (MES) of a transfer function consists of transmitting (EME) on N carrier (s) digital estimation data and estimating (EST) the transmission channel. from these numerical estimation data.
    [0003]
    3. Method according to one of the preceding claims, wherein the detection (DET) of at least one variation is performed over a time window between 0 and 10 ms, in order to detect intermittent or frank defects.
    [0004]
    4. Method according to one of claims 1 to 2, wherein the detection (DET) of at least one variation is performed on a time window equal to the duration of a flight, in order to detect defects characteristic of a slow degradation of said electric cable.
    [0005]
    5. Method according to one of the preceding claims, comprising if a variation is detected, a cable analysis by a reflectometry technique to locate and / or confirm a fault.
    [0006]
    6. Device for monitoring the state of health of an electric cable (C) configured to transmit, in addition to the electrical current, digital communication data according to the in-line carrier technology, the device comprising a transmitter (E) and a receiver (R) arranged between two ends of the cable to be monitored, the receiver (R) comprising a computer configured to implement a method according to one of the preceding claims.
    类似技术:
    公开号 | 公开日 | 专利标题
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    同族专利:
    公开号 | 公开日
    FR3019307B1|2016-03-18|
    WO2015145068A1|2015-10-01|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US4887041A|1988-02-17|1989-12-12|University Of Connecticut|Method and instrumentation for the detection, location and characterization of partial discharges and faults in electric power cables|
    US6233274B1|1995-04-27|2001-05-15|Wavetek Wandel Goltermann|Non-invasive digital cable test system|
    EP2019496A1|2007-07-23|2009-01-28|Sony Corporation|Method for transmitting a signal between a transmitter and a receiver in a power line network, transmitter, receiver, power line communication modem and powerline communication system|
    US20090161781A1|2007-12-21|2009-06-25|Broadcom Corporation|Characterizing channel response using data tone decision feedback|
    FR3038728B1|2015-07-10|2019-04-19|Safran Electronics & Defense|METHOD FOR MONITORING THE STATUS OF A DATA TRANSMISSION CABLE AND DEVICE IMPLEMENTING SAID METHOD|
    FR3060128B1|2016-12-12|2019-03-15|Commissariat A L'energie Atomique Et Aux Energies Alternatives|SYSTEM AND METHOD FOR DETECTING DEFECTS IN A TRANSMISSION LINE USING A COMPLEX SIGNAL|
    CN107317603B|2017-07-03|2020-12-18|河南省科学院应用物理研究所有限公司|Power line communication method and system and power line communication terminal|
    DE202018106543U1|2018-11-19|2019-12-20|Igus Gmbh|System for line monitoring in a line routing device, in particular in an energy chain|
    法律状态:
    2015-03-16| PLFP| Fee payment|Year of fee payment: 2 |
    2016-03-02| PLFP| Fee payment|Year of fee payment: 3 |
    2017-02-10| PLFP| Fee payment|Year of fee payment: 4 |
    2017-11-03| CA| Change of address|Effective date: 20171002 |
    2018-01-19| CA| Change of address|Effective date: 20171218 |
    2018-01-19| CD| Change of name or company name|Owner name: SAFRAN ELECTRICAL & POWER, FR Effective date: 20171218 |
    2018-02-20| PLFP| Fee payment|Year of fee payment: 5 |
    2020-02-20| PLFP| Fee payment|Year of fee payment: 7 |
    2021-02-19| PLFP| Fee payment|Year of fee payment: 8 |
    2022-02-21| PLFP| Fee payment|Year of fee payment: 9 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1452606A|FR3019307B1|2014-03-26|2014-03-26|METHOD FOR MONITORING THE HEALTH STATUS OF AN ELECTRIC CABLE|FR1452606A| FR3019307B1|2014-03-26|2014-03-26|METHOD FOR MONITORING THE HEALTH STATUS OF AN ELECTRIC CABLE|
    PCT/FR2015/050754| WO2015145068A1|2014-03-26|2015-03-25|Method for monitoring the condition of an electrical cable|
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