CN114613116B - External damage prevention early warning method, device, equipment and storage medium - Google Patents

External damage prevention early warning method, device, equipment and storage medium Download PDF

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CN114613116B
CN114613116B CN202210510315.5A CN202210510315A CN114613116B CN 114613116 B CN114613116 B CN 114613116B CN 202210510315 A CN202210510315 A CN 202210510315A CN 114613116 B CN114613116 B CN 114613116B
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vibration
signal
optical fiber
disturbance
time
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CN114613116A (en
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谢文斌
宋巍
严晓华
程晓海
张志鹏
黎彦玲
朱稳兵
吉晓勇
刘彦吟
刘振河
吴宝锋
甘钊
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China Mobile Group Guangdong Co Ltd
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China Mobile Group Guangdong Co Ltd
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    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B31/00—Predictive alarm systems characterised by extrapolation or other computation using updated historic data
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
    • G01H9/004—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means using fibre optic sensors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
    • Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

The invention relates to the technical field of optical fiber sensors, and discloses an external damage prevention early warning method, device, equipment and storage medium. The method comprises the following steps: analyzing the Rayleigh backscattering signal to obtain a real-time vibration signal caused by a disturbance source; performing characteristic analysis on the real-time vibration signal by using a wavelet function, and calculating a wavelet packet coefficient; calculating the disturbance position of a disturbance source based on a wavelet packet coefficient and an optical time domain reflection principle; comparing the Rayleigh backscattering signal with a reflected signal without external force to determine a phase change value of the Rayleigh backscattering signal; determining the type of the vibration event according to the phase change value and the wavelet packet characteristic analysis result; and determining the sensing optical fiber to perform early warning and prompting according to the disturbance position and the type of the vibration event. According to the scheme, the vibration signal of the optical fiber is analyzed, the vibration event type of the disturbance source is determined, the sensing optical fiber is determined to perform early warning prompt, and the technical problem that the hidden danger of external damage of the optical fiber cannot be positioned in real time is solved.

Description

Early warning method, device, equipment and storage medium for preventing external damage
Technical Field
The invention relates to the technical field of optical fiber sensors, in particular to an external-damage-prevention early warning method, device, equipment and storage medium.
Background
In recent years, in order to meet the requirements of city construction and environment beautification, the existing line laying is basically carried out in an underground burying mode, and the underground burying is generally carried out together with the line with the optical fiber for the convenience of subsequent application. However, in the service process of the line, due to the development of social situations, facilities on the ground need to be continuously changed, construction phenomena such as excavation, vibration and the like often occur, the construction phenomena can cause certain damage influence on the underground line, and the damage of the line is more and more serious due to long-time accumulation.
Therefore, the lines are not damaged by external force, so that the line is mainly inspected on each line well regularly by constructors at present or the lines are replaced regularly, and the early warning monitoring cannot be realized in such a way, so that a scheme capable of monitoring the damage of the lines in real time and carrying out early warning is urgently needed to solve the problems.
Disclosure of Invention
The invention mainly aims to determine the type of a vibration event of a disturbance source and determine a sensing optical fiber for early warning prompt by analyzing a vibration signal of the optical fiber, thereby solving the technical problem that the hidden danger of external damage of the optical fiber cannot be positioned in real time.
The invention provides an external-damage-prevention early warning method in a first aspect, which comprises the following steps: obtaining a Rayleigh backscattering signal returned from a sensing optical fiber, and analyzing the Rayleigh backscattering signal to obtain a real-time vibration signal caused by a disturbance source; wavelet packet characteristic analysis is carried out on the real-time vibration signal by utilizing a wavelet function, and a wavelet packet coefficient of the real-time vibration signal is calculated based on a result of the wavelet packet characteristic analysis; calculating the disturbance position of the disturbance source based on the wavelet packet coefficient and the phase sensitive optical time domain reflection principle; based on a detection light pulse generation principle without external force, carrying out multiple harmonic demodulation on the Rayleigh backscattering signal, and determining a waveform section of the Rayleigh backscattering signal which changes; demodulating the waveform section based on a preset frequency modulation function to obtain a demodulation result, and calculating a phase change value of the Rayleigh backscattering signal according to the demodulation result; determining the type of the vibration event according to the phase change value and the result of wavelet packet characteristic analysis; and determining the sensing optical fiber to perform early warning prompt according to the disturbance position and the type of the vibration event.
Optionally, in a first implementation manner of the first aspect of the present invention, the analyzing the rayleigh backscattering signal to obtain a real-time vibration signal caused by a disturbance source includes: performing parameter analysis on the Rayleigh backscattering signal based on an optical signal demodulation principle to obtain vibration amplitude, vibration frequency and disturbance noise; judging whether the vibration amplitude, the vibration frequency and the disturbance noise reach preset corresponding alarm thresholds or not; if so, extracting original parameters of the detection light pulse, wherein the original parameters comprise original vibration amplitude, original vibration frequency and original disturbance noise; and calculating a difference parameter of the Rayleigh backscattering signal relative to the detection light pulse based on the original parameter, the vibration amplitude, the vibration frequency and the disturbance noise, and generating real-time vibration information based on the difference parameter.
Optionally, in a second implementation manner of the first aspect of the present invention, the determining a waveform segment of the rayleigh backscatter signal that changes based on multiple harmonic demodulation of the rayleigh backscatter signal based on a detection light pulse generation principle without external force includes: based on a detection light pulse generation principle without external force, demodulating multiple harmonics of the Rayleigh backscattering signal to obtain an amplitude value and a vibration phase value of the multiple harmonics; generating an algorithm parameter value for constructing a oscillogram based on the amplitude value and the vibration phase value of the multiple harmonics; converting the Rayleigh backscatter signal into a signal waveform by the algorithm parameter; and comparing the signal waveform with the original waveform corresponding to the detection light pulse, and determining a waveform section with a changed waveform.
Optionally, in a third implementation manner of the first aspect of the present invention, the performing wavelet packet feature analysis on the real-time vibration signal by using a wavelet function, and calculating a wavelet packet coefficient of the real-time vibration signal based on a result of the wavelet packet feature analysis includes: intercepting the Rayleigh backscattering signals into a Rayleigh scattering curve generated by a plurality of continuous light pulses according to a time sequence, and extracting a longitudinal time sequence signal of each point on the space in the Rayleigh scattering curve to serve as a time domain signal of a plurality of points; calculating the time domain characteristics of the time domain signals, and the ratio of the time domain characteristics to a preset dynamic characteristic threshold value; judging whether the ratio is larger than a preset value or not; if so, determining that an interference signal exists at the position of the corresponding point, and extracting the corresponding vibration signal section to obtain a time domain signal of the disturbance source; and calculating the ratio of the vibration signal segment to the real-time vibration signal to obtain the wavelet packet coefficient of the real-time vibration signal.
Optionally, in a fourth implementation manner of the first aspect of the present invention, before the determining, according to the phase change value and the result of the wavelet packet feature analysis, a vibration event type of a vibration event, the method further includes: acquiring the embedding environment information of the sensing optical fiber corresponding to the disturbance position; and calculating the weight of interference generated by the environment on the external force and transmitted to the sensing optical fiber based on the information of the burying environment.
Optionally, in a fifth implementation manner of the first aspect of the present invention, the determining a vibration event type of a vibration event according to the phase change value and a result of the wavelet packet feature analysis includes: extracting the characteristics of the time domain signal of the disturbance source according to the wavelet packet characteristic analysis result to obtain multiple types of characteristics of the time domain signal, and inputting the multiple types of characteristics into a preset vibration type classifier for recognition to obtain a vibration event of the disturbance source; calculating an actual phase change value after the disturbance source generates disturbance on the detection light pulse based on the disturbance weight and each phase change value; calculating the distance between the disturbance source and the sensing optical fiber by utilizing a signal transmission principle according to the phase change value and the actual phase change value; comparing each actual phase change value with a preset phase change threshold value, and screening out a time point when the actual phase change value is larger than the preset phase change threshold value based on a comparison result; selecting a maximum value and a minimum value from the screened time points, and simulating the waveform of the vibration event based on the maximum value, the minimum value, the distance and the embedding environment information; and extracting waveform characteristics of the waveform, and determining the vibration event type of the vibration event based on the waveform characteristics.
Optionally, in a sixth implementation manner of the first aspect of the present invention, the determining, according to the disturbance position and the type of the vibration event, that the sensing optical fiber performs an early warning prompt includes: calculating a loss value of the sensing optical fiber within a future period of time by using a preset optical fiber loss model according to the disturbance position and the type of the vibration event, and determining an optical fiber damage level based on the loss value; calculating vibration data generated in a future period of time by using a preset event damage model according to the disturbance position and the vibration event type, and determining an event damage level based on the vibration data; and generating an early warning prompt and an event early warning prompt based on the optical fiber damage grade and the event damage grade so as to be used for the staff to overhaul and investigate.
The second aspect of the present invention provides an external-damage-prevention early warning device, including: the analysis module is used for acquiring a Rayleigh backscattering signal returned from the sensing optical fiber and analyzing the Rayleigh backscattering signal to obtain a real-time vibration signal caused by a disturbance source; the first calculation module is used for performing wavelet packet characteristic analysis on the real-time vibration signal by using a wavelet function and calculating a wavelet packet coefficient of the real-time vibration signal based on a result of the wavelet packet characteristic analysis; the second calculation module is used for calculating the disturbance position of the disturbance source based on the wavelet packet coefficient and the phase-sensitive optical time domain reflection principle; the first determining module is used for demodulating multiple harmonics of the Rayleigh backscattering signal based on a detection light pulse generation principle without external force action and determining a waveform section of the Rayleigh backscattering signal; the demodulation module is used for demodulating the waveform section based on a preset frequency modulation function to obtain a demodulation result and calculating a phase change value of the Rayleigh backscattering signal according to the demodulation result; the second determination module is used for determining the vibration event type of the vibration event according to the phase change value and the result of the wavelet packet characteristic analysis; and the third determining module is used for determining the sensing optical fiber to perform early warning prompt according to the disturbance position and the vibration event type.
Optionally, in a first implementation manner of the second aspect of the present invention, the parsing module is specifically configured to: performing parameter analysis on the Rayleigh backscattering signal based on an optical signal demodulation principle to obtain vibration amplitude, vibration frequency and disturbance noise; judging whether the vibration amplitude, the vibration frequency and the disturbance noise reach preset corresponding alarm thresholds or not; if so, extracting original parameters of the detection light pulse, wherein the original parameters comprise original vibration amplitude, original vibration frequency and original disturbance noise; and calculating a difference parameter of the Rayleigh backscattering signal relative to the detection light pulse based on the original parameter, the vibration amplitude, the vibration frequency and the disturbance noise, and generating real-time vibration information based on the difference parameter.
Optionally, in a second implementation manner of the second aspect of the present invention, the first determining module is specifically configured to: based on a detection light pulse generation principle without external force, demodulating multiple harmonics of the Rayleigh backscattering signal to obtain an amplitude value and a vibration phase value of the multiple harmonics; generating an algorithm parameter value for constructing a oscillogram based on the amplitude value and the vibration phase value of the multiple harmonics; converting the rayleigh backscatter signal into a signal waveform by the algorithm parameter; and comparing the signal waveform with the original waveform corresponding to the detection light pulse, and determining a waveform section with a changed waveform.
Optionally, in a third implementation manner of the second aspect of the present invention, the first calculating module is specifically configured to: the Rayleigh backscattering signals are cut off into Rayleigh scattering curves generated by a plurality of continuous light pulses according to the time sequence, and longitudinal time sequence signals of each point in space in the Rayleigh scattering curves are extracted to serve as time domain signals of the points;
calculating the time domain characteristics of the time domain signals, and the ratio of the time domain characteristics to a preset dynamic characteristic threshold value;
judging whether the ratio is greater than a preset value;
if so, determining that an interference signal exists at the position of the corresponding point, and extracting the corresponding vibration signal section to obtain a time domain signal of the disturbance source;
and calculating the ratio of the vibration signal section to the real-time vibration signal to obtain a wavelet packet coefficient of the real-time vibration signal.
Optionally, in a fourth implementation manner of the second aspect of the present invention, the anti-external-damage early warning apparatus further includes: the acquisition module is used for acquiring the embedding environment information of the sensing optical fiber corresponding to the disturbance position; and the second calculation module is used for calculating the interference weight of the environment on the signal transmission of the external force to the sensing optical fiber based on the information of the burying environment.
Optionally, in a fifth implementation manner of the second aspect of the present invention, the second determining module is specifically configured to: extracting the characteristics of the time domain signal of the disturbance source according to the wavelet packet characteristic analysis result to obtain multiple types of characteristics of the time domain signal, and inputting the multiple types of characteristics into a preset vibration type classifier for recognition to obtain a vibration event of the disturbance source;
calculating an actual phase change value after the disturbance source generates disturbance on the detection light pulse based on the disturbance weight and each phase change value;
calculating the distance between the disturbance source and the sensing optical fiber by utilizing a signal transmission principle according to the phase change value and the actual phase change value;
comparing each actual phase change value with a preset phase change threshold value, and screening out the time points of which the actual phase change values are greater than the preset phase change threshold value on the basis of the comparison result;
selecting a maximum value and a minimum value from the screened time points, and simulating the waveform of the vibration event based on the maximum value, the minimum value, the distance and the embedding environment information;
and extracting waveform characteristics of the waveform, and determining the vibration event type of the vibration event based on the waveform characteristics.
Optionally, in a sixth implementation manner of the second aspect of the present invention, the third determining module includes: the calculation unit is used for calculating a loss value of the sensing optical fiber within a future period of time by using a preset optical fiber loss model according to the disturbance position and the vibration event type, and determining an optical fiber damage level based on the loss value; the determining unit is used for calculating vibration data generated in a future period of time by using a preset event damage model according to the disturbance position and the vibration event type, and determining an event damage level based on the vibration data; and the generation unit is used for generating an optical fiber early warning prompt and an event early warning prompt based on the optical fiber damage grade and the event damage grade so as to be used for maintenance and investigation by workers.
A third aspect of the present invention provides an external-damage-prevention early warning device, including: a memory having instructions stored therein and at least one processor, the memory and the at least one processor interconnected by a line;
the at least one processor calls the instructions in the memory to enable the anti-vandalism early warning device to execute the steps of the anti-vandalism early warning method.
A fourth aspect of the present invention provides a computer-readable storage medium, which stores instructions that, when executed on a computer, cause the computer to perform the steps of the anti-vandalism warning method described above.
In the technical scheme provided by the invention, the real-time vibration signal caused by a disturbance source is obtained by analyzing the obtained Rayleigh backscattering signal; wavelet packet characteristic analysis is carried out on the real-time vibration signal by utilizing a wavelet function, and a wavelet packet coefficient of the real-time vibration signal is calculated based on a result of the wavelet packet characteristic analysis; calculating the disturbance position of a disturbance source based on a wavelet packet coefficient and a phase sensitive optical time domain reflection principle; comparing the Rayleigh backscattering signal with a reflected signal without external force to determine a phase change value of the Rayleigh backscattering signal; determining the type of the vibration event according to the phase change value and the result of wavelet packet characteristic analysis; and determining the sensing optical fiber to perform early warning and prompting according to the disturbance position and the type of the vibration event. According to the scheme, the vibration signal of the optical fiber is analyzed, the vibration event type of the disturbance source is determined, the sensing optical fiber is determined to perform early warning prompt, and the technical problem that the hidden danger of external damage of the optical fiber cannot be positioned in real time is solved.
Drawings
Fig. 1 is a schematic diagram of a first embodiment of an anti-external-damage early warning method provided by the present invention;
fig. 2 is a schematic diagram of a second embodiment of the anti-external damage early warning method provided by the present invention;
fig. 3 is a schematic diagram of a third embodiment of the anti-external damage early warning method provided by the present invention;
fig. 4 is a schematic diagram of a fourth embodiment of the anti-external damage early warning method provided by the present invention;
fig. 5 is a schematic diagram of a fifth embodiment of the early warning method for preventing external damage according to the present invention;
fig. 6 is a schematic diagram of a sixth embodiment of the early warning method for preventing external damage according to the present invention;
fig. 7 is a schematic view of a first embodiment of the anti-external-damage early warning device provided by the invention;
fig. 8 is a schematic view of a second embodiment of the anti-external-damage early warning device provided by the present invention;
fig. 9 is a schematic diagram of an embodiment of the anti-vandalism warning device provided by the present invention.
Detailed Description
The embodiment of the invention provides an anti-external-damage early warning method, an anti-external-damage early warning device, an anti-external-damage early warning equipment and a storage medium, wherein in the technical scheme of the invention, firstly, a real-time vibration signal caused by a disturbance source is obtained by analyzing an obtained Rayleigh backscattering signal; wavelet packet characteristic analysis is carried out on the real-time vibration signal by utilizing a wavelet function, and a wavelet packet coefficient of the real-time vibration signal is calculated based on a result of the wavelet packet characteristic analysis; calculating the disturbance position of a disturbance source based on a wavelet packet coefficient and a phase sensitive optical time domain reflection principle; comparing the Rayleigh backscattering signal with a reflected signal without external force, and determining a phase change value of the Rayleigh backscattering signal; determining the type of the vibration event according to the phase change value and the result of wavelet packet characteristic analysis; and determining the sensing optical fiber to perform early warning prompt according to the disturbance position and the type of the vibration event. According to the scheme, the vibration signal of the optical fiber is analyzed, the vibration event type of the disturbance source is determined, the sensing optical fiber is determined to perform early warning prompt, and the technical problem that the hidden danger of external damage of the optical fiber cannot be positioned in real time is solved.
The terms "first," "second," "third," "fourth," and the like in the description and in the claims, as well as in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that the embodiments described herein may be practiced otherwise than as specifically illustrated or described herein. Furthermore, the terms "comprises," "comprising," or "having," and any variations thereof, are intended to cover non-exclusive inclusions, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
For convenience of understanding, a specific flow of the embodiment of the present invention is described below, and with reference to fig. 1, a first embodiment of the early warning method for preventing an external damage in the embodiment of the present invention includes:
101. obtaining a Rayleigh backscattering signal returned from the sensing optical fiber, and analyzing the Rayleigh backscattering signal to obtain a real-time vibration signal caused by a disturbance source;
in this embodiment, the distributed vibration sensing optical fiber is a distributed sensor, and the "distributed" refers to that each point on the optical fiber has sensing capability, and the basic principle of the distributed optical fiber vibration sensing technology (Φ -OTDR) is that the characteristics of optical characteristics such as phases and the like of light waves and backward rayleigh scattered light when the light waves and the backward rayleigh scattered light are transmitted in the optical fiber are sensitive to vibration, when a certain position of the optical fiber is disturbed by vibration, the refractive index of the optical fiber at the position will change, so that the characteristics of the light waves and the backward rayleigh scattered light at the position change, and after analyzing and processing backward rayleigh scattered light signals, vibration information of each point of the optical fiber can be obtained. Each point has the ability to measure vibration, i.e. there are numerous points in a fiber that can measure the arrival time of vibration.
In this embodiment, a phase-sensitive optical time domain reflectometry (Φ -OTDR) technique is used to detect vibration, thereby implementing monitoring of an external damage event. The Φ -OTDR typically employs a kHz-level narrow linewidth laser as a light source, and senses the external disturbances to which the fiber is subjected by injecting probe light pulses into the sensing fiber and detecting the resulting Rayleigh Backscatter (RBS) signal in the sensing fiber. The technology has extremely high sensitivity and high measurement response speed, can realize long-distance full-distributed non-blind-zone sensing, and is very suitable for monitoring various micro-disturbance events around the optical fiber.
102. Wavelet packet characteristic analysis is carried out on the real-time vibration signals by utilizing a wavelet function, and wavelet packet coefficients of the real-time vibration signals are calculated based on the result of the wavelet packet characteristic analysis;
in this embodiment, data analysis is performed on the real-time vibration information, multiple types of features of the time domain signal of the vibration position are extracted as feature vectors, and the feature vectors are input into the vibration type classifier for identification, so as to obtain the disturbance position and the vibration event of the disturbance source. The vibration types are knocking, climbing and squeezing.
Preferably, this embodiment further includes wavelet packet feature analysis, where the wavelet packet feature analysis includes: continuous multiframe time domain signals from the beginning of vibration are used as vibration signals, wavelet packet decomposition is carried out on the vibration signals by utilizing a wavelet function to obtain wavelet packet coefficients of each layer, wavelet packet energy distribution characteristics are obtained through calculation according to the wavelet packet coefficients, and the wavelet packet energy distribution characteristics and the time domain characteristics jointly form multi-class characteristic vectors of the vibration signals.
Preferably, spectral subtraction noise reduction processing may also be used before the wavelet packet feature analysis, the spectral subtraction noise reduction processing including: in a static environment without a vibration event, continuous multiframe time domain signals on each space position point obtained through multiple times of preprocessing are used as noise signals of each space position point, the power spectrum of the vibration signals is calculated according to the vibration signals of the vibration positions, the average power spectrum of the noise signals of the vibration points is subtracted from the power spectrum of the vibration signals to obtain a new signal power spectrum, and the new signal power spectrum is subjected to inverse Fourier transform reduction to obtain the vibration signals after noise reduction.
Further, the algorithm of the normal vibration signal transmission mode is as follows:
Figure 578939DEST_PATH_IMAGE001
further, the algorithm of the external force vibration signal transmission mode is as follows:
Figure 426678DEST_PATH_IMAGE002
wherein t is time, M is the highest order of the higher harmonics generated by the vibration signal, M is the M-order harmonics generated by the vibration signal, Am is the amplitude of the M-order harmonics, mfs is the vibration frequency of the M-order harmonics, β M is the vibration phase of the M-order harmonics, Am (t) is the frequency modulation function of the vibration signal in the external force vibration signal transmission mode, bm (t) is the amplitude modulation function of the vibration signal in the external force vibration signal transmission mode, p is the highest order of the higher harmonics, k is the k-order harmonics, and is a parameter in the frequency modulation function of the corresponding k-order harmonics, and is a parameter in the amplitude modulation function of the corresponding k-order harmonics.
Specifically, if the time for the waveform to change is 5s, 5s is substituted into the expressions am (t) and bm (t) under the detection condition, and the phase value and the amplitude value in the normal sensing fiber transmission mode at 5s are 3.15 and 1.83, respectively, and the phase value and the amplitude value in the sensing fiber transmission mode vibrated by the external force at 5s are 2.78 and 1.67, respectively, and the phase change value and the amplitude change value are 11.7% and 8.7%, respectively. And because the time for transmitting and changing the waveform is 5s, if the propagation speed of the vibration signal is 5m/s, the position where the waveform changes is 25m away from the signal transmitting end, thereby determining the position of the vibration caused by the external force on the detection sensing optical fiber.
103. Calculating the disturbance position of a disturbance source based on a wavelet packet coefficient and a phase sensitive optical time domain reflection principle;
in this embodiment, the disturbance position of the disturbance source is calculated based on the wavelet packet coefficient and the phase-sensitive optical time domain reflection principle. Specifically, wavelet packet decomposition is carried out on the vibration signal by utilizing a wavelet function to obtain wavelet packet coefficients of each layer, wavelet packet energy distribution characteristics are obtained through calculation according to the wavelet packet coefficients, and the wavelet packet energy distribution characteristics and time domain characteristics jointly form multi-class characteristic vectors of the vibration signal.
Specifically, if the waveform change time is 5s, 5s is substituted into the expressions am (t) and bm (t) under the detection condition, and the phase value and the amplitude value in the normal sensing fiber transmission mode at 5s are 3.15 and 1.83, respectively, and the phase value and the amplitude value in the sensing fiber transmission mode vibrated by an external force at 5s are 2.78 and 1.67, respectively, and 11.7% and 8.7%, respectively. And because the time of the waveform transmission change is 5s, if the propagation speed of the vibration signal is 5m/s, the position where the waveform changes is 25m away from the signal transmitting end, so that the position of the detection sensing optical fiber vibrated by the external force is determined.
104. Based on a detection light pulse generation principle without external force, multi-time harmonic demodulation is carried out on the Rayleigh backscattering signal, and a waveform section of the Rayleigh backscattering signal which changes is determined;
in this embodiment, the signal waveform transmitted by the normal sensing optical fiber is compared with the signal waveform transmitted by the sensing optical fiber damaged by an external force, so as to find out whether the waveform of the vibration signal transmitted by the sensing optical fiber changes: if no change exists, the section of the detection sensing optical fiber is not damaged by external force; if there is a change, the change values of the amplitude and the phase are calculated.
The amplitude and phase change values are calculated as follows: and in the same detection period, obtaining an expression of a normal sensing optical fiber transmission algorithm on the detection sensing optical fiber according to the transmitted signal data, and simultaneously obtaining an expression of frequency modulation am (t) and an expression of amplitude modulation value bm (t).
And obtaining the received signal data and the obtained values of the parameters Am and beta m in the normal sensing optical fiber transmission algorithm to obtain an expression of the sensing optical fiber signal transmission algorithm damaged by the external force on the sensing optical fiber to be detected, and obtaining a frequency modulation a'm (t) expression and an amplitude modulation b'm (t) expression.
In this embodiment, the position where the waveform changes is obtained according to the time when the waveform changes and the propagation speed of the vibration signal on the detection sensing optical fiber, that is, the position where the vibration is caused by the external force can be obtained.
In the detection process, in order to ensure effective transmission of vibration signals on different types of sensing optical fibers and obtain clear and definite transmission paths of the vibration signals, detection signals with different frequencies are correspondingly selected for detection distances with different lengths. Specifically, the longer the detection distance, the lower the frequency of the vibration signal used.
105. Demodulating the waveform section based on a preset frequency modulation function to obtain a demodulation result, and calculating a phase change value of the Rayleigh backscattering signal according to the demodulation result;
in this embodiment, the waveform segment is demodulated based on a preset frequency modulation function to obtain a demodulation result, and the phase change value of the rayleigh backscatter signal is calculated according to the demodulation result. And the demodulation result is obtained by demodulating the waveform segment, so as to obtain the phase value of each moment on the waveform segment.
And demodulating the waveform segment by using a frequency modulation function corresponding to the detection light pulse to obtain a phase value of each moment on the waveform segment. Specifically, in the detection process, in order to ensure effective transmission of the vibration signals on the sensing optical fibers of different models and obtain a clear and definite transmission path of the vibration signals, the detection distances of different lengths are selected to correspond to the detection signals of different frequencies. Specifically, the longer the detection distance, the lower the frequency of the employed vibration signal.
Illustratively, if the length of the sensing optical fiber to be detected is 10m, a vibration signal of 50Hz is correspondingly selected; if the length of the sensing optical fiber to be detected is 20m, a vibration signal of 40Hz is correspondingly selected; if the length of the sensing optical fiber to be detected is 30m, a vibration signal of 30Hz is correspondingly selected.
Further, a phase change value of the rayleigh backscatter signal is calculated based on the phase value at each time and the phase value of the probe light pulse. And calculating a phase change value of the Rayleigh backscatter signal based on the phase value at each time and the phase value of the detection light pulse. The sensing optical fiber which is 20m long and is vibrated by external force is exemplarily explained, when a vibration signal of 40Hz is adopted for detection, a signal oscillogram which is obtained by fitting sending signal data according to a normal sensing optical fiber signal transmission mode is compared with a signal oscillogram which is obtained by fitting receiving signal data according to an external force vibration signal transmission mode, if the detected waveform is changed, the amplitude and phase change are continuously calculated, and the phase change value of the Rayleigh backscattering signal is obtained.
106. Determining the type of the vibration event according to the phase change value and the wavelet packet characteristic analysis result;
in this embodiment, the type of the vibration event is determined according to the phase change value and the result of the wavelet packet characteristic analysis. Specifically, in the measurement principle, when external disturbance occurs, the length, refractive index, etc. of the optical fiber may change along with the external disturbance event, which finally results in a change in the phase of the RBS optical signal generated at the corresponding position of the optical fiber. The phi-OTDR can quantitatively measure the external disturbance event by analyzing the RBS phase change of the position before and after the external disturbance occurs. The principle is shown in fig. 2:
the phase difference of the 2 reference regions R1 and R2 before and after the external disturbance event can be expressed as:
Figure 913154DEST_PATH_IMAGE003
phase change information of the disturbance position can be extracted through signal processing, optical fiber length change caused by the fact that external disturbance acts on the optical fiber to be detected can be obtained, and finally reconstruction of an external sound field is achieved. By combining signal analysis, the construction phenomenon near the optical fiber can be accurately positioned and quickly identified, so that the aims of early warning, quick inspection and troubleshooting, reduction of the probability of failure and guarantee of safe operation of the device to which the optical fiber belongs are fulfilled.
By monitoring the disturbance such as the destructive behavior of the optical fiber with potential safety hazard, the construction of the surrounding environment and the like on the line in real time, acquiring and analyzing information and judging the position, type and strength of the disturbance, line maintenance personnel are helped to discover the stealing, invasion and destructive behavior of the equipment to which the optical fiber belongs in time. The device can monitor, accurately position and intelligently analyze in real time when an event occurs, can also realize early warning of accident occurrence, effectively solves early warning monitoring of optical fiber damage, and provides warning, intelligent analysis and decision support assistance for operators on duty.
Because optic fibre receives external force vibration to the amplitude and the phase change production of vibration signal comparatively obvious change, accessible signal amplitude or phase change value judge whether have optic fibre receive external force vibration, optic fibre receive the size of external force vibration and optic fibre receive the shape of external force vibration, through carrying out waveform fitting to vibration signal and reacing: different optical fibers are vibrated by external force and correspond to different amplitude and phase change values, so that the detection standard of the optical fibers vibrated by the external force is established. Wherein, the damage level of the optical fiber under the vibration of the external force is corresponded by setting the threshold values with different amplitude changes.
107. And determining the sensing optical fiber to perform early warning prompt according to the disturbance position and the type of the vibration event.
In this embodiment, the signal waveform transmitted by the normal sensing optical fiber is compared with the signal waveform transmitted by the sensing optical fiber damaged by an external force, so as to find out whether the waveform of the vibration signal transmitted by the sensing optical fiber changes: if no change exists, the section of the detection sensing optical fiber is not damaged by external force; if there is a change, the change values of the amplitude and the phase are calculated. The position of the waveform change can be obtained according to the time of the waveform change and the propagation speed of the vibration signal on the detection sensing optical fiber, and the position of the vibration caused by the external force can be obtained.
Specifically, data analysis is performed on the target vibration signal, multiple types of features of the time domain signal of the vibration position are extracted to serve as feature vectors, the feature vectors are input into a vibration type classifier to be recognized, and the initial disturbance position of the target vibration signal and a vibration event corresponding to the initial disturbance position are obtained. The vibration types are knocking, climbing and squeezing.
Phase change information of a disturbance position can be extracted through signal processing, so that the length change of the optical fiber caused by the external disturbance action on the optical fiber to be detected can be obtained, and the reconstruction of an external sound field is finally realized. By combining signal analysis, the construction phenomenon near the optical fiber can be accurately positioned and quickly identified, so that the early warning, the quick patrol and investigation and the probability of reducing the fault are achieved.
Specifically, in the embodiment of the invention, the monitoring and positioning of the external broken hidden danger of a single line or a plurality of series/parallel lines can be realized, a full-line monitoring system is formed, and on the other hand, the full-flow control of all external broken hidden danger points can be realized, so that line-plane combination is realized. The system software is transmitted by a GPRS/WIFI/OPGW optical fiber network and other forms of network transmission through an erected communication server, a real-time monitoring result of a monitoring device host is connected to a remote monitoring center, a pre-warning data list is monitored in real time, a GIS module shows and related managers browse monitoring operation logs, and discovery and processing whole-flow management and control of each hidden danger point are achieved by taking an event as a unit. Meanwhile, by using the APP software of the mobile terminal, the event early warning information can be issued and received in real time. Real-time data sharing through the monitoring center can timely push fault early warning information, people closest to the monitoring center can be arranged to quickly reach the scene, accidents are avoided, operation and maintenance can be guided through the remote terminal, and mobile interconnection of information is achieved.
In the embodiment of the invention, the real-time vibration signal caused by a disturbance source is obtained by analyzing the obtained Rayleigh backscattering signal; wavelet packet characteristic analysis is carried out on the real-time vibration signal by utilizing a wavelet function, and a wavelet packet coefficient of the real-time vibration signal is calculated based on a result of the wavelet packet characteristic analysis; calculating the disturbance position of a disturbance source based on a wavelet packet coefficient and a phase sensitive optical time domain reflection principle; comparing the Rayleigh backscattering signal with a reflected signal without external force to determine a phase change value of the Rayleigh backscattering signal; determining the type of the vibration event according to the phase change value and the wavelet packet characteristic analysis result; and determining the sensing optical fiber to perform early warning and prompting according to the disturbance position and the type of the vibration event. According to the scheme, the vibration signal of the optical fiber is analyzed, the vibration event type of the disturbance source is determined, the sensing optical fiber is determined to perform early warning prompt, and the technical problem that the hidden danger of external damage of the optical fiber cannot be positioned in real time is solved.
Referring to fig. 2, a second embodiment of the early warning method for preventing the external damage in the embodiment of the present invention includes:
201. performing parameter analysis on the Rayleigh backscattering signal based on an optical signal demodulation principle to obtain vibration amplitude, vibration frequency and disturbance noise;
in this embodiment, the rayleigh backscattering signal is subjected to parameter analysis based on an optical signal demodulation principle to obtain a vibration amplitude, a vibration frequency and a disturbance noise. The analytical method of the Rayleigh backscattering signal comprises the following steps: the received optical vibration signals can be analyzed to obtain information such as amplitude, frequency and the like of vibration of each point of the optical fiber, vibration characteristics generated by different vibrations are different, and the same vibration signal can be extracted.
202. Judging whether the vibration amplitude, the vibration frequency and the disturbance noise reach preset corresponding alarm thresholds or not;
in this embodiment, the measurement points on the distributed vibration sensing optical fiber are continuous, and the distance between the point that receives the first vibration signal and the vibration source is closest to the vibration source, and the distance between the point that receives the first vibration signal and the vibration source may be used as the radial distance between the vibration source and the optical fiber.
203. If so, extracting original parameters of the detection light pulse, wherein the original parameters comprise original vibration amplitude, original vibration frequency and original disturbance noise;
in this embodiment, according to the obtained vibration signals of a plurality of points, time differences between the other points and the first point receiving the vibration signals are respectively extracted; and according to the distance between each measuring point and the first point, the extracted time difference of the received vibration signal and the propagation speed of the vibration in the medium, establishing a linear equation set by adopting a maximum likelihood estimation method, and solving the distance between the first point and the vibration source by adopting a least square method, namely the radial distance between the vibration source and the optical fiber measuring point.
The propagation medium of the vibration is the surrounding environment, generally soil, in which the optical fiber is laid. Specifically, data cleaning is carried out based on the vibration signal data list, dynamic combination of the initial vibration signals and actual services can be considered, and therefore different states of the initial vibration signals in different time periods are taken into consideration, so that when the initial vibration signals are cleaned, not only can data cleaning accuracy be guaranteed, but also influence on normal use of subsequent service data due to data cleaning can be avoided.
204. Calculating a difference parameter of the Rayleigh backscattering signal relative to the detection light pulse based on the original parameter, the vibration amplitude, the vibration frequency and the disturbance noise, and generating real-time vibration information based on the difference parameter;
in this embodiment, based on the original parameters, the vibration amplitude, the vibration frequency, and the disturbance noise, the difference parameters of the rayleigh backscatter signal with respect to the detection light pulse are calculated, and the real-time vibration information is generated based on the difference parameters.
Specifically, according to the obtained vibration signals of a plurality of points, time differences of the other points and the first point receiving the vibration signals are respectively extracted; and according to the distance between each measuring point and the first point, the extracted time difference of the received vibration signal and the propagation speed of the vibration in the medium, establishing a linear equation set by adopting a maximum likelihood estimation method, and solving the distance between the first point and the vibration source by adopting a least square method, namely the radial distance between the vibration source and the optical fiber measuring point.
The propagation medium of the vibration is the surrounding environment of the optical fiber laying, generally soil. Specifically, data cleaning is carried out based on the vibration signal data list, dynamic combination of the initial vibration signals and actual services can be considered, and therefore different states of the initial vibration signals in different time periods are taken into consideration, so that when the initial vibration signals are cleaned, not only can data cleaning accuracy be guaranteed, but also influence on normal use of subsequent service data due to data cleaning can be avoided.
205. The Rayleigh backscattering signal is cut off into a Rayleigh scattering curve generated by a plurality of continuous light pulses according to the time sequence, and a longitudinal time sequence signal of each point in space in the Rayleigh scattering curve is extracted to be used as a time domain signal of a plurality of points;
in this embodiment, the narrow linewidth laser has a working wavelength of 1550nm and a linewidth of less than 100kHz, and is configured to emit strongly coherent continuous probe light; the acousto-optic modulator is an all-fiber acousto-optic modulator, the connecting fiber is a polarization maintaining fiber and is used for modulating strong coherent continuous detection light emitted by the narrow-linewidth laser into pulse light; and the input end of the first erbium-doped fiber amplifier is connected with the output end of the acousto-optic modulator and is used for amplifying the pulse optical signal.
The two collected optical time-domain reflected light signals can be seen that the signal collected by the first channel is not saturated, and the signal intensity of the initial position in each rayleigh scattering curve is always the maximum, so that the initial position of each scattering curve can be determined by detecting the maximum value of each N data points of the signal collected by the first channel, each initial position is marked as T, wherein k represents the period sequence number, and k is 1, 2, …, m. And intercepting N/2 continuous data points of the first channel signal after the position T and N/2 continuous data points of the second channel signal after the position T + N/2, and combining to obtain a Rayleigh scattering light intensity curve x [ k ] of each point in the kth period, wherein i represents a space position point, and i is 1, 2, … and N.
For the ith spatial position node in transverse space, its longitudinal time series signal is represented as x [ k ], where k is 1, 2 …, m.
206. Calculating the time domain characteristics of the time domain signals, and the ratio of the time domain characteristics to a preset dynamic characteristic threshold;
in this embodiment, for a longitudinal time series signal at an i-th spatial position node in a transverse space, subtracting x [ k ] from x [ k +1] to obtain a time domain signal s [ k ] of the i-th spatial node after differential processing, and performing signal preprocessing until the signal preprocessing is completed.
207. Judging whether the ratio is greater than a preset value;
in this embodiment, it is determined whether the ratio of the time domain characteristic to the preset dynamic characteristic threshold is greater than a preset value. And if so, determining that the interference signal exists at the position corresponding to the point, and determining the disturbance position corresponding to the real-time vibration signal according to the interference frequency of the interference signal.
208. If so, determining that an interference signal exists at the position of the corresponding point, and extracting a corresponding vibration signal segment to obtain a time domain signal of the disturbance source;
in this embodiment, in a static environment without a vibration event, data of ten data frames is preprocessed, and an enhanced signal corresponding to the ith spatial node of each frame is counted as a noise signal N [ k ], where k is 1, 2 …, m. For the ith space node, the first ten frames of time domain signals obtained by preprocessing are taken as noise signals, and the average short-time energy threshold EN, the noise average level threshold V and the noise average power spectrum N [ omega ], omega represents frequency spectrum components of ten frames of noise are calculated. Corresponding to above, where j is 1, 2 …, 10, representing the number of frames.
And calculating the short-time energy E and the over-level rate L of each space node of each frame. Where Ψ is an indicator function, the bracketed condition holds with a value of 1, and otherwise 0.
The short-time energy E is compared with a short-time energy threshold EN, and if E/EN > α, which is a manually set threshold parameter, and the level-exceeding rate L > β, which is usually set to α 4.5 and β 0.35, it is determined that there is interference. Under the condition of interference, the thresholds EN and V are not updated; and in the case of no interference, the EN, the V and the N [ omega ] are weighted and updated by the original threshold value and the current data characteristic value.
209. Calculating the ratio of the vibration signal segment to the real-time vibration signal to obtain the wavelet packet coefficient of the real-time vibration signal;
in this embodiment, the ratio of the vibration signal segment to the real-time vibration signal is calculated to obtain the wavelet packet coefficient of the real-time vibration signal. Specifically, the average value of the short-time energy ratio of continuous ten-frame time domain signals of a spatial position node with vibration, the average value of the over-level rate, the vibration duration and the energy distribution ratio of each layer after wavelet packet decomposition of a noise reduction signal of the vibration are combined to form a characteristic vector, the energy distribution characteristics of the wavelet packets can represent the difference of energy distribution of different types of vibration signals on different frequency bands, the time domain characteristics can distinguish continuous vibration from instantaneous vibration, strong vibration and weak vibration, the continuous vibration and the instantaneous vibration can be combined to form a vibration signal characteristic vector, and the vibration signal characteristic vector is input into a trained support vector machine classifier model for identification, so that the identification accuracy of the classifier can be greatly improved.
Specifically, the training method of the classifier is to perform vibration type simulation before the system is formally operated, simulate different vibration behaviors and strong interference behaviors in the environment at a known position, extract 200 groups of feature vectors of different types of vibration signals at the known position, and train by using a support vector machine classifier model to obtain the vibration type classifier.
210. Calculating the disturbance position of a disturbance source based on a wavelet packet coefficient and a phase sensitive optical time domain reflection principle;
211. based on a detection light pulse generation principle without external force, multi-time harmonic demodulation is carried out on the Rayleigh backscattering signal, and a waveform section of the Rayleigh backscattering signal changing is determined;
212. demodulating the waveform section based on a preset frequency modulation function to obtain a demodulation result, and calculating a phase change value of the Rayleigh backscattering signal according to the demodulation result;
213. determining the type of the vibration event according to the phase change value and the wavelet packet characteristic analysis result;
214. and determining the sensing optical fiber to perform early warning and prompting according to the disturbance position and the type of the vibration event.
The steps 210-214 in the present embodiment are similar to the steps 103-107 in the first embodiment, and are not described herein again.
In the embodiment of the invention, the real-time vibration signal caused by a disturbance source is obtained by analyzing the obtained Rayleigh backscattering signal; wavelet packet characteristic analysis is carried out on the real-time vibration signal by utilizing a wavelet function, and a wavelet packet coefficient of the real-time vibration signal is calculated based on a result of the wavelet packet characteristic analysis; calculating the disturbance position of a disturbance source based on a wavelet packet coefficient and a phase sensitive optical time domain reflection principle; comparing the Rayleigh backscattering signal with a reflected signal without external force to determine a phase change value of the Rayleigh backscattering signal; determining the type of the vibration event according to the phase change value and the result of wavelet packet characteristic analysis; and determining the sensing optical fiber to perform early warning prompt according to the disturbance position and the type of the vibration event. According to the scheme, the vibration signal of the optical fiber is analyzed, the vibration event type of the disturbance source is determined, the sensing optical fiber is determined to perform early warning prompt, and the technical problem that the hidden danger of external damage of the optical fiber cannot be positioned in real time is solved.
Referring to fig. 3, a third embodiment of the early warning method for preventing external damage in the embodiment of the present invention includes:
301. obtaining a Rayleigh backscattering signal returned from the sensing optical fiber, and analyzing the Rayleigh backscattering signal to obtain a real-time vibration signal caused by a disturbance source;
302. wavelet packet characteristic analysis is carried out on the real-time vibration signals by utilizing a wavelet function, and wavelet packet coefficients of the real-time vibration signals are calculated based on the result of the wavelet packet characteristic analysis;
303. calculating the disturbance position of a disturbance source based on a wavelet packet coefficient and a phase sensitive optical time domain reflection principle;
304. based on a detection light pulse generation principle without external force, multi-time harmonic demodulation is carried out on the Rayleigh backscattering signal to obtain an amplitude value and a vibration phase value of the multi-time harmonic;
in this embodiment, the amplitude variation value and the phase variation value of the vibration signal are obtained by comparing the signal waveform transmitted by the normal optical fiber with the signal waveform transmitted by the optical fiber vibrated by the external force, so as to determine the level of the external force vibration of the optical fiber.
The signal waveform fitting process of the vibration signal in normal optical fiber transmission comprises the following steps: and collecting the transmitted vibration signal data in the detection process, solving parameters and parameter expressions in a normal optical fiber signal transmission mode algorithm, and obtaining a normal optical fiber signal transmission algorithm expression under the detection condition, wherein the frequency modulation expression am (t) and the amplitude modulation expression bm (t) can be determined. And obtaining the transmission waveform of the vibration signal on the normal optical fiber by using the solved normal optical fiber signal transmission algorithm expression.
The signal waveform fitting process of the vibration signal in normal optical fiber transmission comprises the following steps: acquiring signal data of the same vibration signal transmitted by the optical fiber under the vibration of the external force by the optical fiber, obtaining an optical fiber signal transmission mode algorithm expression of the vibration signal under the external force under the same condition through Am, beta m and received signal data of the vibration signal in a normal optical fiber signal transmission algorithm, obtaining a frequency modulation expression a'm (t) and an amplitude modulation expression b'm (t), and fitting the transmission waveform of the vibration signal on the optical fiber under the external force vibration by the obtained optical fiber signal transmission mode algorithm expression of the vibration signal under the external force vibration.
305. Generating an algorithm parameter value for constructing a oscillogram based on the amplitude value and the vibration phase value of the multiple harmonics;
in this embodiment, a vibration signal is transmitted at one end of the detection optical fiber, and the vibration signal is received at the other end of the detection optical fiber, and the distance between the signal transmitting end and the signal receiving end is within the effective transmission distance of the vibration signal. And acquiring and fitting the vibration signal transmitted by the optical fiber to be detected by using a normal optical fiber signal transmission mode on the transmitted vibration signal data to form a vibration signal waveform transmitted on the optical fiber to be detected.
306. Converting the Rayleigh backscattering signal into a signal waveform through an algorithm parameter;
in this embodiment, a vibration signal is transmitted at one end of the detection optical fiber, and the vibration signal is received at the other end of the detection optical fiber, and the distance between the signal transmitting end and the signal receiving end is within the effective transmission distance of the vibration signal. And acquiring and fitting the vibration signal transmitted by the optical fiber to be detected by utilizing an external force vibration signal transmission mode according to the transmitted vibration signal data to form a vibration signal waveform transmitted on the optical fiber to be detected.
The signal waveform fitting process of the vibration signal in the optical fiber transmission under the vibration of the external force is as follows: and collecting the transmitted vibration signal data in the detection process, solving parameters and parameter expressions in a normal optical fiber signal transmission mode algorithm, and obtaining a normal optical fiber signal transmission algorithm expression under the detection condition, wherein the frequency modulation expression am (t) and the amplitude modulation expression bm (t) can be determined. And obtaining the transmission waveform of the vibration signal on the normal optical fiber by using the solved normal optical fiber signal transmission algorithm expression.
307. Comparing the signal waveform with an original waveform corresponding to the detection light pulse, and determining a waveform section with a changed waveform;
in the embodiment, the time of waveform change is obtained and is substituted into the expression of am (t), and the phase value of normal sensing optical fiber signal transmission at the time is obtained; substituting the time into a bm (t) expression to obtain an amplitude value of the normal sensing optical fiber signal transmission at the time; substituting the time into an expression a'm (t), and obtaining a phase value of the sensing optical fiber signal transmission of the time vibrated by the external force; and substituting the time into an expression a'm (t), and obtaining the amplitude value of the sensing optical fiber signal transmission vibrated by the external force at the time. And comparing the phase value of the normal time sensing optical fiber signal transmission with the phase value of the sensing optical fiber signal transmission vibrated by the external force to obtain a phase change value and also obtain an amplitude change value.
And obtaining the position of the waveform change according to the time of the waveform change and the propagation speed of the vibration signal on the detection sensing optical fiber, namely obtaining the position of the vibration caused by the external force.
Specifically, the embodiment of the invention accurately grasps whether the optical fiber has hidden danger risks and grades damaged by external force, accurately positions the risk position points, and can early warn the high-voltage optical fiber external damage event. Therefore, the difficulty problem of safe operation and maintenance management of the optical fiber circuit is solved to the greatest extent, and intelligent, automatic and digital management of the optical fiber circuit is realized.
308. Demodulating the waveform section based on a preset frequency modulation function to obtain a demodulation result, and calculating a phase change value of the Rayleigh backscattering signal according to the demodulation result;
309. determining the type of the vibration event according to the phase change value and the wavelet packet characteristic analysis result;
310. and determining the sensing optical fiber to perform early warning prompt according to the disturbance position and the type of the vibration event.
The steps 301-.
In the embodiment of the invention, the real-time vibration signal caused by the disturbance source is obtained by analyzing the obtained Rayleigh backscattering signal; wavelet packet characteristic analysis is carried out on the real-time vibration signal by utilizing a wavelet function, and a wavelet packet coefficient of the real-time vibration signal is calculated based on a result of the wavelet packet characteristic analysis; calculating the disturbance position of a disturbance source based on a wavelet packet coefficient and a phase sensitive optical time domain reflection principle; comparing the Rayleigh backscattering signal with a reflected signal without external force, and determining a phase change value of the Rayleigh backscattering signal; determining the type of the vibration event according to the phase change value and the wavelet packet characteristic analysis result; and determining the sensing optical fiber to perform early warning prompt according to the disturbance position and the type of the vibration event. According to the scheme, the vibration signal of the optical fiber is analyzed, the vibration event type of the disturbance source is determined, the sensing optical fiber is determined to perform early warning prompt, and the technical problem that the hidden danger of external damage of the optical fiber cannot be positioned in real time is solved.
Referring to fig. 4, a fourth embodiment of the early warning method for preventing external damage in the embodiment of the present invention includes:
401. obtaining a Rayleigh backscattering signal returned from the sensing optical fiber, and analyzing the Rayleigh backscattering signal to obtain a real-time vibration signal caused by a disturbance source;
402. wavelet packet characteristic analysis is carried out on the real-time vibration signal by utilizing a wavelet function, and a wavelet packet coefficient of the real-time vibration signal is calculated based on a result of the wavelet packet characteristic analysis;
403. calculating the disturbance position of a disturbance source based on a wavelet packet coefficient and a phase sensitive optical time domain reflection principle;
404. based on a detection light pulse generation principle without external force, multi-time harmonic demodulation is carried out on the Rayleigh backscattering signal, and a waveform section of the Rayleigh backscattering signal which changes is determined;
405. demodulating the waveform section based on a preset frequency modulation function to obtain a demodulation result, and calculating a phase change value of the Rayleigh backscattering signal according to the demodulation result;
406. acquiring the embedding environment information of the sensing optical fiber corresponding to the disturbance position;
in this embodiment, the information of the embedding environment of the sensing optical fiber corresponding to the disturbance position is obtained. The buried environment may be hard rock, seawater, or a soft soil layer. The damage degree of the optical fiber corresponding to external force is different in different embedding environments, and the early warning level of the external damage of the optical fiber is also different.
407. Based on the information of the embedded environment, calculating the interference weight of the environment on the signal transmission to the sensing optical fiber generated by the external force;
in this embodiment, based on the information of the embedded environment, the interference weight of the environment on the transmission of the signal generated by the external force to the sensing fiber is calculated. For example, the buried environment may be hard rock, or may be seawater, or a soft soil layer. The damage degree of the optical fiber corresponding to the external force is different in different embedding environments, so that the interference weight of the signal generated by the corresponding environment to the external force and transmitted to the sensing optical fiber can be calculated according to the information of the embedding environments.
408. Extracting the characteristics of the time domain signal of the disturbance source according to the wavelet packet characteristic analysis result to obtain multi-class characteristics of the time domain signal, and inputting the multi-class characteristics into a preset vibration type classifier for identification to obtain a vibration event of the disturbance source;
in this embodiment, feature extraction is performed on the time domain signal of the disturbance source according to the result of wavelet packet feature analysis to obtain multiple types of features of the time domain signal, and the multiple types of features are input into a preset vibration type classifier to be recognized to obtain a vibration event of the disturbance source. The wavelet packet feature analysis comprises: continuous multi-frame time domain signals starting from vibration are used as vibration signals, wavelet packet decomposition is carried out on the vibration signals through a wavelet function to obtain wavelet packet coefficients of all layers, wavelet packet energy distribution characteristics are obtained through calculation according to the wavelet packet coefficients, and the wavelet packet energy distribution characteristics and the time domain characteristics jointly form multi-class characteristic vectors of the vibration signals.
Preferably, a spectral subtraction noise reduction process may also be used before the wavelet packet feature analysis, the spectral subtraction noise reduction process including: in a static environment without a vibration event, continuous multiframe time domain signals on each space position point obtained through multiple times of preprocessing are used as noise signals of each space position point, the power spectrum of the vibration signals is calculated according to the vibration signals of the vibration positions, the average power spectrum of the noise signals of the vibration points is subtracted from the power spectrum of the vibration signals to obtain a new signal power spectrum, and the new signal power spectrum is subjected to inverse Fourier transform reduction to obtain the vibration signals after noise reduction.
409. Calculating an actual phase change value after the disturbance source generates disturbance on the detection light pulse based on the disturbance weight and each phase change value;
in this embodiment, based on the interference weight and each phase change value, an actual phase change value after the interference is generated by the interference source for the probe light pulse is calculated. Specifically, the narrow linewidth laser has a working wavelength of 1550nm and a linewidth of less than 100kHz, and is used for emitting strong coherent continuous probe light; the acousto-optic modulator is an all-fiber acousto-optic modulator, the connecting fiber is a polarization maintaining fiber and is used for modulating strong coherent continuous detection light emitted by the narrow-linewidth laser into pulse light; and the input end of the first erbium-doped fiber amplifier is connected with the output end of the acousto-optic modulator and is used for amplifying the pulse optical signal.
The two collected optical time-domain reflected light signals can be seen that the signal collected by the first channel is not saturated, and the signal intensity of the initial position in each rayleigh scattering curve is always the maximum, so that the initial position of each scattering curve can be determined by detecting the maximum value of each N data points of the signal collected by the first channel, each initial position is marked as T, wherein k represents the period sequence number, and k is 1, 2, …, m. And intercepting N/2 continuous data points of the first channel signal after the position T and N/2 continuous data points of the second channel signal after the position T + N/2, and combining to obtain a Rayleigh scattering light intensity curve x [ k ] of each point in the kth period, wherein i represents a space position point, and i is 1, 2, … and N.
410. Calculating the distance between the disturbance source and the sensing optical fiber by using a signal transmission principle according to the phase change value and the actual phase change value;
in this embodiment, the distance between the disturbance source and the sensing fiber is calculated according to the phase change value and the actual phase change value by using a signal transmission principle. Specifically, the calculation process of the amplitude and phase change values is as follows: and in the same detection period, obtaining an expression of a normal sensing optical fiber transmission algorithm on the detection sensing optical fiber according to the transmitted signal data, and simultaneously obtaining an expression of frequency modulation am (t) and an expression of amplitude modulation value bm (t). According to the time when the waveform changes and the propagation speed of the vibration signal on the sensing optical fiber, the position where the waveform changes is obtained, namely the position where the vibration is caused by external force can be obtained, namely the distance between the disturbance source and the sensing optical fiber is calculated by utilizing the signal transmission principle.
411. Comparing each actual phase change value with a preset phase change threshold value, and screening out a time point when the actual phase change value is larger than the preset phase change threshold value based on a comparison result;
in this embodiment, each actual phase change value is compared with a preset phase change threshold, and a time point at which the actual phase change value is greater than the preset phase change threshold is screened out based on the comparison result.
Specifically, the signal waveform transmitted by the normal sensing fiber is compared with the signal waveform transmitted by the sensing fiber damaged by an external force, so that whether the vibration signal waveform transmitted by the sensing fiber changes can be found out: if no change exists, the section of the detection sensing optical fiber is not damaged by external force; if there is a change, the change values of the amplitude and the phase are calculated.
412. Selecting a maximum value and a minimum value from the screened time points, and simulating the waveform of the vibration event based on the maximum value, the minimum value, the distance and the embedding environment information;
in this embodiment, the maximum value and the minimum value are selected from the screened time points, and the waveform of the vibration event is simulated based on the maximum value and the minimum value, the distance, and the embedding environment information.
Specifically, in the measurement principle, when external disturbance occurs, the length, refractive index, etc. of the optical fiber may change along with the external disturbance event, which finally results in a change in the phase of the RBS optical signal generated at the corresponding position of the optical fiber. The phi-OTDR can quantitatively measure the external disturbance event by analyzing the RBS phase change of the position before and after the external disturbance occurs.
413. Extracting waveform characteristics of the waveform, and determining the type of the vibration event based on the waveform characteristics;
in this embodiment, the waveform feature of the waveform is extracted, and the type of the vibration event of the disturbance source is determined based on the waveform feature. Specifically, the multi-class features of the time domain signal of the vibration position are extracted to serve as feature vectors, and the feature vectors are input into a vibration type classifier to be recognized, so that the initial disturbance position of the target vibration signal and a vibration event corresponding to the initial disturbance position are obtained. The vibration types are knocking, climbing and squeezing.
Preferably, this embodiment further includes wavelet packet feature analysis, where the wavelet packet feature analysis includes: continuous multiframe time domain signals from the beginning of vibration are used as vibration signals, wavelet packet decomposition is carried out on the vibration signals by utilizing a wavelet function to obtain wavelet packet coefficients of each layer, wavelet packet energy distribution characteristics are obtained through calculation according to the wavelet packet coefficients, and the wavelet packet energy distribution characteristics and the time domain characteristics jointly form multi-class characteristic vectors of the vibration signals.
Specifically, if the waveform change time is 5s, 5s is substituted into the expressions am (t) and bm (t) under the detection condition, and the phase value and the amplitude value in the normal sensing fiber transmission mode at 5s are 3.15 and 1.83, respectively, and the phase value and the amplitude value in the sensing fiber transmission mode vibrated by an external force at 5s are 2.78 and 1.67, respectively, and 11.7% and 8.7%, respectively. And because the time for transmitting and changing the waveform is 5s, if the propagation speed of the vibration signal is 5m/s, the position where the waveform changes is 25m away from the signal transmitting end, thereby determining the position of the vibration caused by the external force on the detection sensing optical fiber.
414. And determining the sensing optical fiber to perform early warning and prompting according to the disturbance position and the type of the vibration event.
The steps 401, 405, 414 in this embodiment are similar to the steps 101, 104, 106 in the first embodiment, and are not described herein again.
In the embodiment of the invention, the real-time vibration signal caused by the disturbance source is obtained by analyzing the obtained Rayleigh backscattering signal; wavelet packet characteristic analysis is carried out on the real-time vibration signals by utilizing a wavelet function, and wavelet packet coefficients of the real-time vibration signals are calculated based on the result of the wavelet packet characteristic analysis; calculating the disturbance position of a disturbance source based on a wavelet packet coefficient and a phase sensitive optical time domain reflection principle; comparing the Rayleigh backscattering signal with a reflected signal without external force, and determining a phase change value of the Rayleigh backscattering signal; determining the type of the vibration event according to the phase change value and the wavelet packet characteristic analysis result; and determining the sensing optical fiber to perform early warning and prompting according to the disturbance position and the type of the vibration event. According to the scheme, the vibration signal of the optical fiber is analyzed, the vibration event type of the disturbance source is determined, the sensing optical fiber is determined to perform early warning prompt, and the technical problem that the hidden danger of external damage of the optical fiber cannot be positioned in real time is solved.
Referring to fig. 5, a fifth embodiment of the early warning method for preventing the external damage in the embodiment of the present invention includes:
501. obtaining a Rayleigh backscattering signal returned from the sensing optical fiber, and analyzing the Rayleigh backscattering signal to obtain a real-time vibration signal caused by a disturbance source;
502. wavelet packet characteristic analysis is carried out on the real-time vibration signal by utilizing a wavelet function, and a wavelet packet coefficient of the real-time vibration signal is calculated based on a result of the wavelet packet characteristic analysis;
503. calculating the disturbance position of a disturbance source based on a wavelet packet coefficient and a phase sensitive optical time domain reflection principle;
504. based on a detection light pulse generation principle without external force, multi-time harmonic demodulation is carried out on the Rayleigh backscattering signal, and a waveform section of the Rayleigh backscattering signal changing is determined;
505. demodulating the waveform section based on a preset frequency modulation function to obtain a demodulation result, and calculating a phase change value of the Rayleigh backscattering signal according to the demodulation result;
506. determining the type of the vibration event according to the phase change value and the wavelet packet characteristic analysis result;
507. calculating a loss value of the sensing optical fiber within a period of time in the future by using a preset optical fiber loss model according to the disturbance position and the type of the vibration event, and determining the damage level of the optical fiber based on the loss value;
in this embodiment, according to the disturbance position and the type of the vibration event, a loss value of the sensing optical fiber in a future period of time is calculated by using a preset optical fiber loss model, and an optical fiber damage level is determined based on the loss value.
Specifically, the loss value of the sensing optical fiber in a future period is calculated by combining an optical fiber loss model, and the damage level of the optical fiber is determined based on the loss value, so that the aims of early warning in advance, quick patrol and troubleshooting, reduction of the probability of failure and guarantee of safe operation of the optical fiber are achieved.
Specifically, the system performs statistical analysis on the time domain characteristics of the vibration signal, studies the rule that the form of the signal changes along with time, extracts typical characteristic quantities such as short-time energy, average zero-crossing rate, resonant frequency, sub-band energy, shannon entropy and the like as the basis for signal judgment and identification, and combines noise suppression methods such as spectral subtraction, adaptive filtering and the like, so that the false alarm rate can be effectively reduced.
508. Calculating vibration data generated in a future period of time by using a preset event damage model according to the disturbance position and the type of the vibration event, and determining an event damage level based on the vibration data;
in this embodiment, vibration data generated in a future period of time is calculated by using a preset event damage model according to the disturbance position and the type of the vibration event, and an event damage level is determined based on the vibration data.
Specifically, because optic fibre receives external force vibration to the amplitude and the phase change production of vibration signal comparatively obviously change, accessible signal amplitude or phase change value judge whether there is optic fibre to receive external force vibration, optic fibre receive the size of external force vibration and optic fibre receive the shape of external force vibration, through carrying out waveform fitting to vibration signal and reacing: different optical fibers are vibrated by external force and correspond to different amplitude and phase change values, so that the detection standard of the optical fibers vibrated by the external force is established. Wherein, the damage level of the optical fiber under the vibration of the external force is corresponded by setting the threshold values with different amplitude changes.
509. And generating an optical fiber early warning prompt and an event early warning prompt based on the optical fiber damage grade and the event damage grade so as to be used for the staff to overhaul and investigate.
In this embodiment, based on the optical fiber damage level and the event damage level, an optical fiber early warning prompt and an event early warning prompt are generated for the staff to overhaul and investigate. Specifically, by monitoring the disturbance on the optical fiber, such as the destructive behavior with potential safety hazard, the construction of the surrounding environment and the like, in real time, acquiring and analyzing information, and judging the position, type and strength of the disturbance, the method helps line maintenance personnel to find the stealing, intrusion and destructive behaviors of the related equipment to which the optical fiber belongs in time. The device can monitor, accurately position and intelligently analyze in real time when an event occurs, and can also realize early warning of accident occurrence.
Specifically, the system performs statistical analysis on the time domain characteristics of the vibration signal, studies the rule that the form of the signal changes along with time, extracts typical characteristic quantities such as short-time energy, average zero-crossing rate, resonant frequency, sub-band energy, shannon entropy and the like as the basis for signal judgment and identification, and combines noise suppression methods such as spectral subtraction, adaptive filtering and the like, so that the false alarm rate can be effectively reduced.
The steps 501-505 in the present embodiment are similar to the steps 101-105 in the first embodiment, and are not described herein again.
In the embodiment of the invention, the real-time vibration signal caused by a disturbance source is obtained by analyzing the obtained Rayleigh backscattering signal; wavelet packet characteristic analysis is carried out on the real-time vibration signal by utilizing a wavelet function, and a wavelet packet coefficient of the real-time vibration signal is calculated based on a result of the wavelet packet characteristic analysis; calculating the disturbance position of a disturbance source based on a wavelet packet coefficient and a phase sensitive optical time domain reflection principle; comparing the Rayleigh backscattering signal with a reflected signal without external force to determine a phase change value of the Rayleigh backscattering signal; determining the type of the vibration event according to the phase change value and the result of wavelet packet characteristic analysis; and determining the sensing optical fiber to perform early warning prompt according to the disturbance position and the type of the vibration event. According to the scheme, the vibration signal of the optical fiber is analyzed, the vibration event type of the disturbance source is determined, the sensing optical fiber is determined to perform early warning prompt, and the technical problem that the hidden danger of external damage of the optical fiber cannot be positioned in real time is solved.
The above description of the early warning method for preventing external damage in the embodiment of the present invention, and the following description of the early warning device for preventing external damage in the embodiment of the present invention refer to fig. 7, where a first embodiment of the early warning device for preventing external damage in the embodiment of the present invention includes:
the analysis module 601 is configured to acquire a rayleigh backscattering signal returned from the sensing optical fiber, and analyze the rayleigh backscattering signal to obtain a real-time vibration signal caused by a disturbance source;
a first calculating module 602, configured to perform wavelet packet feature analysis on the real-time vibration signal by using a wavelet function, and calculate a wavelet packet coefficient of the real-time vibration signal based on a result of the wavelet packet feature analysis;
a second calculating module 603, configured to calculate a disturbance position of the disturbance source based on the wavelet packet coefficient and a phase-sensitive optical time domain reflection principle;
a first determining module 604, configured to demodulate multiple harmonics of the rayleigh backscatter signal based on a detection light pulse generation principle without an external force, and determine a waveform segment in which the rayleigh backscatter signal changes;
a demodulation module 605, configured to demodulate the waveform segment based on a preset frequency modulation function to obtain a demodulation result, and calculate a phase variation value of the rayleigh backscatter signal according to the demodulation result;
a second determining module 606, configured to determine a vibration event type of the vibration event according to the phase change value and a result of the wavelet packet feature analysis;
and a third determining module 607, configured to determine, according to the disturbance position and the type of the vibration event, that the sensing optical fiber performs an early warning prompt.
In the embodiment of the invention, the real-time vibration signal caused by a disturbance source is obtained by analyzing the obtained Rayleigh backscattering signal; wavelet packet characteristic analysis is carried out on the real-time vibration signals by utilizing a wavelet function, and wavelet packet coefficients of the real-time vibration signals are calculated based on the result of the wavelet packet characteristic analysis; calculating the disturbance position of a disturbance source based on a wavelet packet coefficient and a phase sensitive optical time domain reflection principle; comparing the Rayleigh backscattering signal with a reflected signal without external force to determine a phase change value of the Rayleigh backscattering signal; determining the type of the vibration event according to the phase change value and the result of wavelet packet characteristic analysis; and determining the sensing optical fiber to perform early warning prompt according to the disturbance position and the type of the vibration event. According to the scheme, the vibration signal of the optical fiber is analyzed, the vibration event type of the disturbance source is determined, the sensing optical fiber is determined to perform early warning prompt, and the technical problem that the hidden danger of external damage of the optical fiber cannot be positioned in real time is solved.
Referring to fig. 8, a second embodiment of the early warning device for preventing external damage in the embodiment of the present invention specifically includes:
the analysis module 601 is configured to acquire a rayleigh backscattering signal returned from the sensing optical fiber, and analyze the rayleigh backscattering signal to obtain a real-time vibration signal caused by a disturbance source;
a first calculating module 602, configured to perform wavelet packet feature analysis on the real-time vibration signal by using a wavelet function, and calculate a wavelet packet coefficient of the real-time vibration signal based on a result of the wavelet packet feature analysis;
a second calculating module 603, configured to calculate a disturbance position of the disturbance source based on the wavelet packet coefficient and a phase-sensitive optical time domain reflection principle;
a first determining module 604, configured to demodulate multiple harmonics of the rayleigh backscatter signal based on a detection light pulse generation principle without an external force, and determine a waveform segment in which the rayleigh backscatter signal changes;
a demodulation module 605, configured to demodulate the waveform segment based on a preset frequency modulation function to obtain a demodulation result, and calculate a phase variation value of the rayleigh backscatter signal according to the demodulation result;
a second determining module 606, configured to determine a vibration event type of the vibration event according to the phase change value and a result of the wavelet packet feature analysis;
and a third determining module 607, configured to determine, according to the disturbance position and the type of the vibration event, that the sensing optical fiber performs an early warning prompt.
In this embodiment, the parsing module 601 is specifically configured to:
performing parameter analysis on the Rayleigh backscattering signal based on an optical signal demodulation principle to obtain vibration amplitude, vibration frequency and disturbance noise;
judging whether the vibration amplitude, the vibration frequency and the disturbance noise reach preset corresponding alarm thresholds or not;
if so, extracting original parameters of the detection light pulse, wherein the original parameters comprise original vibration amplitude, original vibration frequency and original disturbance noise;
and calculating a difference parameter of the Rayleigh backscattering signal relative to the detection light pulse based on the original parameter, the vibration amplitude, the vibration frequency and the disturbance noise, and generating real-time vibration information based on the difference parameter.
In this embodiment, the first determining module 604 is specifically configured to:
based on a detection light pulse generation principle without external force, demodulating multiple harmonics of the Rayleigh backscattering signal to obtain an amplitude value and a vibration phase value of the multiple harmonics;
generating an algorithm parameter value for constructing a oscillogram based on the amplitude value and the vibration phase value of the multiple harmonics;
converting the rayleigh backscatter signal into a signal waveform by the algorithm parameter;
and comparing the signal waveform with the original waveform corresponding to the detection light pulse, and determining a waveform section with a changed waveform.
In this embodiment, the first calculating module 602 is specifically configured to:
intercepting the Rayleigh backscattering signals into a Rayleigh scattering curve generated by a plurality of continuous light pulses according to a time sequence, and extracting a longitudinal time sequence signal of each point on the space in the Rayleigh scattering curve to serve as a time domain signal of a plurality of points;
calculating the time domain characteristics of the time domain signals, and the ratio of the time domain characteristics to a preset dynamic characteristic threshold value;
judging whether the ratio is larger than a preset value or not;
if so, determining that an interference signal exists at the position of the corresponding point, and calculating the disturbance position of the disturbance source by utilizing a phase sensitive optical time domain reflection principle according to the interference frequency of the interference signal;
and extracting the characteristics of the time domain signal of the disturbance position to obtain multi-class characteristics of the time domain signal, and inputting the multi-class characteristics into a preset vibration type classifier for identification to obtain a vibration event of the disturbance source.
In this embodiment, the early warning device for preventing external damage further includes:
an obtaining module 608, configured to obtain information of a burying environment of the sensing fiber corresponding to the disturbance position;
and a third calculating module 609, configured to calculate, based on the information about the burying environment, a weight of interference caused by the environment to the signal transmitted to the sensing fiber by the external force.
In this embodiment, the second determining module 606 is specifically configured to:
calculating an actual phase change value after the disturbance source generates disturbance on the detection light pulse based on the disturbance weight and each phase change value;
comparing each actual phase change value with a preset phase change threshold value, and screening out the time points of which the actual phase change values are greater than the preset phase change threshold value on the basis of the comparison result;
selecting a maximum value and a minimum value from the screened time points, and calculating the length change of the interfered optical fiber in the sensing optical fiber by using an optical transmission principle based on the maximum value and the minimum value;
determining the type of the vibration event of the disturbance source based on the fiber length change and the number of actual phase change values greater than a preset phase change threshold.
In this embodiment, the third determining module 607 includes:
a calculating unit 6071, configured to calculate, according to the disturbance position and the vibration event type, a loss value of the sensing optical fiber in a future period of time by using a preset optical fiber loss model, and determine an optical fiber damage level based on the loss value;
a determining unit 6072, configured to calculate, according to the disturbance position and the vibration event type, vibration data generated in a future period of time by using a preset event damage model, and determine an event damage level based on the vibration data;
and a generating unit 6073, configured to generate an optical fiber early warning prompt and an event early warning prompt based on the optical fiber damage level and the event damage level, so as to allow a worker to perform maintenance and troubleshooting.
In the embodiment of the invention, the real-time vibration signal caused by the disturbance source is obtained by analyzing the obtained Rayleigh backscattering signal; wavelet packet characteristic analysis is carried out on the real-time vibration signals by utilizing a wavelet function, and wavelet packet coefficients of the real-time vibration signals are calculated based on the result of the wavelet packet characteristic analysis; calculating the disturbance position of a disturbance source based on a wavelet packet coefficient and a phase sensitive optical time domain reflection principle; comparing the Rayleigh backscattering signal with a reflected signal without external force to determine a phase change value of the Rayleigh backscattering signal; determining the type of the vibration event according to the phase change value and the result of wavelet packet characteristic analysis; and determining the sensing optical fiber to perform early warning and prompting according to the disturbance position and the type of the vibration event. According to the scheme, the vibration signal of the optical fiber is analyzed, the vibration event type of the disturbance source is determined, the sensing optical fiber is determined to perform early warning prompt, and the technical problem that the hidden danger of external damage of the optical fiber cannot be positioned in real time is solved.
Fig. 7 and 8 describe the anti-tampering early warning apparatus in the embodiment of the present invention in detail from the perspective of the modular functional entity, and the anti-tampering early warning apparatus in the embodiment of the present invention is described in detail from the perspective of hardware processing.
Fig. 9 is a schematic structural diagram of an anti-tamper warning device according to an embodiment of the present invention, where the anti-tamper warning device 800 may generate a relatively large difference due to different configurations or performances, and may include one or more processors (CPUs) 810 (e.g., one or more processors) and a memory 820, and one or more storage media 830 (e.g., one or more mass storage devices) storing an application 833 or data 832. Memory 820 and storage medium 830 may be, among other things, transient or persistent storage. The program stored in the storage medium 830 may include one or more modules (not shown), each of which may include a series of instruction operations on the anti-tampering warning device 800. Further, the processor 810 may be configured to communicate with the storage medium 830, and execute a series of instruction operations in the storage medium 830 on the anti-tamper warning device 800, so as to implement the steps of the anti-tamper warning method provided by the above-mentioned method embodiments.
Anti-tampering pre-warning device 800 may also include one or more power supplies 840, one or more wired or wireless network interfaces 850, one or more input-output interfaces 860, and/or one or more operating systems 831, such as Windows Server, Mac OS X, Unix, Linux, FreeBSD, and the like. It will be understood by those skilled in the art that the configuration of the anti-tamper warning device shown in fig. 8 does not constitute a limitation of the anti-tamper warning device provided herein, and may include more or fewer components than those shown, or some components in combination, or a different arrangement of components.
The present invention also provides a computer-readable storage medium, which may be a non-volatile computer-readable storage medium, and may also be a volatile computer-readable storage medium, where instructions are stored in the computer-readable storage medium, and when the instructions are run on a computer, the instructions cause the computer to execute the steps of the anti-external-damage early warning method.
It can be clearly understood by those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a read-only memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (10)

1. The anti-external-damage early warning method is characterized by comprising the following steps:
obtaining a Rayleigh backscattering signal returned from a sensing optical fiber, and analyzing the Rayleigh backscattering signal to obtain a real-time vibration signal caused by a disturbance source;
wavelet packet characteristic analysis is carried out on the real-time vibration signal by utilizing a wavelet function, and a wavelet packet coefficient of the real-time vibration signal is calculated based on a result of the wavelet packet characteristic analysis;
calculating the disturbance position of the disturbance source based on the wavelet packet coefficient and the phase-sensitive optical time domain reflection principle;
based on a detection light pulse generation principle without external force, carrying out multiple harmonic demodulation on the Rayleigh backscattering signal, and determining a waveform section of the Rayleigh backscattering signal which changes;
demodulating the waveform section based on a preset frequency modulation function to obtain a demodulation result, and calculating a phase change value of the Rayleigh backscattering signal according to the demodulation result;
determining the type of the vibration event according to the phase change value and the result of wavelet packet characteristic analysis;
and determining the early warning prompt of the sensing optical fiber according to the disturbance position and the type of the vibration event.
2. The anti-outburst early warning method according to claim 1, wherein the analyzing the rayleigh backscattering signal to obtain a real-time vibration signal caused by a disturbance source comprises:
performing parameter analysis on the Rayleigh backscattering signal based on an optical signal demodulation principle to obtain vibration amplitude, vibration frequency and disturbance noise;
judging whether the vibration amplitude, the vibration frequency and the disturbance noise reach preset corresponding alarm thresholds or not;
if so, extracting original parameters of the detection light pulse, wherein the original parameters comprise original vibration amplitude, original vibration frequency and original disturbance noise;
and calculating a difference parameter of the Rayleigh backscattering signal relative to the detection light pulse based on the original parameter, the vibration amplitude, the vibration frequency and the disturbance noise, and generating real-time vibration information based on the difference parameter.
3. The anti-external-damage early warning method according to claim 1 or 2, wherein the determining the waveform segment of the rayleigh backscatter signal that changes based on the detection light pulse generation principle without external force comprises:
based on a detection light pulse generation principle without external force, demodulating multiple harmonics of the Rayleigh backscattering signal to obtain an amplitude value and a vibration phase value of the multiple harmonics;
generating an algorithm parameter value for constructing a oscillogram based on the amplitude value and the vibration phase value of the multiple harmonics;
converting the Rayleigh backscatter signal into a signal waveform by the algorithm parameter value;
and comparing the signal waveform with the original waveform corresponding to the detection light pulse, and determining a waveform section with a changed waveform.
4. The anti-external-damage early warning method according to claim 3, wherein the wavelet packet feature analysis is performed on the real-time vibration signal by using a wavelet function, and the wavelet packet coefficient of the real-time vibration signal is calculated based on the result of the wavelet packet feature analysis, and the method comprises the following steps:
intercepting the Rayleigh backscattering signals into a Rayleigh scattering curve generated by a plurality of continuous light pulses according to a time sequence, and extracting a longitudinal time sequence signal of each point on the space in the Rayleigh scattering curve to serve as a time domain signal of a plurality of points;
calculating the time domain characteristics of the time domain signals, and the ratio of the time domain characteristics to a preset dynamic characteristic threshold value;
judging whether the ratio is larger than a preset value or not;
if so, determining that an interference signal exists at the position of the corresponding point, and extracting a corresponding vibration signal segment to obtain a time domain signal of the disturbance source;
and calculating the ratio of the vibration signal section to the real-time vibration signal to obtain a wavelet packet coefficient of the real-time vibration signal.
5. The anti-external-damage early warning method according to claim 4, before determining the type of the vibration event according to the phase change value and the result of the wavelet packet characteristic analysis, further comprising:
acquiring the embedding environment information of the sensing optical fiber corresponding to the disturbance position;
and calculating the interference weight of the environment on the signal transmission of the external force to the sensing optical fiber based on the information of the embedded environment.
6. The anti-outburst early warning method according to claim 5, wherein the determining the type of the vibration event according to the phase change value and the result of the wavelet packet feature analysis comprises:
extracting the characteristics of the time domain signal of the disturbance source according to the wavelet packet characteristic analysis result to obtain multiple types of characteristics of the time domain signal, and inputting the multiple types of characteristics into a preset vibration type classifier for recognition to obtain a vibration event of the disturbance source;
calculating an actual phase change value after the disturbance source generates disturbance on the detection light pulse based on the disturbance weight and each phase change value;
calculating the distance between the disturbance source and the sensing optical fiber by utilizing a signal transmission principle according to the phase change value and the actual phase change value;
comparing each actual phase change value with a preset phase change threshold value, and screening out the time points of which the actual phase change values are greater than the preset phase change threshold value on the basis of the comparison result;
selecting a maximum value and a minimum value from the screened time points, and simulating the waveform of the vibration event based on the maximum value, the minimum value, the distance and the burying environment information;
and extracting waveform characteristics of the waveform, and determining the type of the vibration event based on the waveform characteristics.
7. The anti-external-damage early warning method according to claim 6, wherein the determining the sensing optical fiber to perform early warning prompting according to the disturbance position and the vibration event type comprises:
calculating a loss value of the sensing optical fiber within a future period of time by using a preset optical fiber loss model according to the disturbance position and the type of the vibration event, and determining an optical fiber damage level based on the loss value;
calculating vibration data generated in a future period of time by using a preset event damage model according to the disturbance position and the vibration event type, and determining an event damage level based on the vibration data;
and generating an optical fiber early warning prompt and an event early warning prompt based on the optical fiber damage grade and the event damage grade so as to be used for maintenance and investigation by workers.
8. The utility model provides a prevent outer broken early warning device which characterized in that, prevent outer broken early warning device includes:
the analysis module is used for acquiring a Rayleigh backscattering signal returned from the sensing optical fiber and analyzing the Rayleigh backscattering signal to obtain a real-time vibration signal caused by a disturbance source;
the first calculation module is used for performing wavelet packet characteristic analysis on the real-time vibration signal by using a wavelet function and calculating a wavelet packet coefficient of the real-time vibration signal based on a result of the wavelet packet characteristic analysis;
the second calculation module is used for calculating the disturbance position of the disturbance source based on the wavelet packet coefficient and the phase-sensitive optical time domain reflection principle;
the first determining module is used for demodulating multiple harmonics of the Rayleigh backscattering signal based on a detection light pulse generating principle without external force, and determining a waveform segment of the Rayleigh backscattering signal;
the demodulation module is used for demodulating the waveform section based on a preset frequency modulation function to obtain a demodulation result and calculating a phase change value of the Rayleigh backscattering signal according to the demodulation result;
the second determination module is used for determining the vibration event type of the vibration event according to the phase change value and the result of the wavelet packet characteristic analysis;
and the third determining module is used for determining the early warning prompt of the sensing optical fiber according to the disturbance position and the type of the vibration event.
9. The utility model provides a prevent outer broken early warning equipment which characterized in that, prevent outer broken early warning equipment includes: a memory having instructions stored therein and at least one processor, the memory and the at least one processor interconnected by a line;
the at least one processor invokes the instructions in the memory to cause the anti-tampering pre-warning device to perform the steps of the anti-tampering pre-warning method according to any one of claims 1 to 7.
10. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the anti-breach warning method according to any of claims 1-7.
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