Abnormal vibration monitoring method and device of AC cable based on distributed acoustic wave sensing

Abstract

The present application relates to an abnormal vibration monitoring method for AC cables based on distributed acoustic wave sensing. The method includes: obtaining the vibration signal of the AC cable based on distributed acoustic wave sensing vibration monitoring; sampling the vibration signal according to a preset vibration sampling frequency to obtain a sampling signal, wherein the preset vibration sampling frequency is an integer multiple of the power frequency of the AC cable transmission; demodulating n sampling signals collected in time sequence to obtain the phase of the sampling signal at each position of the AC cable; subtracting the phases of any two positions that meet the differential distance from the beginning of the AC cable to obtain n differential phase data; then grouping and phase unwinding the n differential phase data, obtaining a spectrum diagram based on the unwinding differential phase data, and obtaining energy data; when the energy data at a certain position meets the abnormal condition, the position is an abnormal vibration position, the AC cable is a single-phase cable, and the grouping re-sampling frequency is twice the power frequency of the transmission.

Description

Technical Field

[0001] The present application relates to the technical field of cable monitoring, and in particular to a method and device for monitoring abnormal vibration of an AC cable based on distributed acoustic wave sensing. Background Art

[0002] As the consumption of non-renewable resources increases, the focus of resource development is gradually shifting to renewable energy. Submarine cables are an important carrier for marine power transmission. With the rapid development of island economy, the number of submarine cables is also increasing. At the same time, the frequency of submarine cable problems is also increasing.

[0003] In related technologies, distributed acoustic wave sensors can be used to monitor the vibration state of submarine cables, and to provide early warning of certain submarine cable failure threats, such as when the submarine cable is caught by an anchor, and to locate some existing faults. The length of submarine cables is generally tens of kilometers, and many distributed optical fiber sensing products use balanced detection technology and digital demodulation algorithms to detect and process Rayleigh scattering signals and restore vibration waveforms. The advantage is that the measured signal can be amplified, the detection range is longer, and it can meet the monitoring needs of the entire submarine cable.

[0004] Distributed fiber optic sensor product demodulation errors will cause DAS (distributed acoustic sensor) to be unable to detect abnormal vibrations. For example, it cannot distinguish the vibration signals generated by anchors hanging on submarine cables, ocean currents, etc., and thus cannot detect threats in time. There are many problems that lead to vibration demodulation errors. Therefore, how to avoid or weaken the monitoring demodulation errors of distributed fiber optic sensors to reduce false alarms and improve monitoring accuracy has become an urgent problem to be solved. Summary of the invention

[0005] Based on this, it is necessary to provide an abnormal vibration monitoring method for AC cables based on distributed acoustic wave sensing to address the above technical problems, which can eliminate the influence of the power frequency when the AC cable is energized.

[0006] In a first aspect, the present application provides a method for monitoring abnormal vibration of an AC cable based on distributed acoustic wave sensing. The method comprises:

[0007] Based on distributed acoustic wave sensing vibration monitoring, the vibration signal of AC cable is obtained;

[0008] Sampling the vibration signal according to a preset vibration sampling frequency to obtain a sampling signal, wherein the preset vibration sampling frequency is an integer multiple of the power frequency of the AC cable transmission;

[0009] Demodulate the n sampling signals collected in time sequence respectively according to a phase demodulation algorithm to obtain the phase of the sampling signal at each position of the AC cable;

[0010] Starting from the head end of the AC cable, the phases of any two positions on the AC cable that meet the differential distance are subtracted to obtain n differential phase data, where the differential distance is determined according to the required spatial resolution;

[0011] Dividing n differential phase data into multiple groups of signal data according to the time sequence of the vibration signal returning in the AC cable, and performing phase unwrapping on each group of signal data in the time domain to obtain multiple groups of unwrapped differential phase data;

[0012] The differential phase data after unwinding at different positions of the AC cable are respectively transformed into frequency spectra through Fourier transformation to calculate the energy data;

[0013] When the energy data at a certain position on the AC cable meets an abnormal condition, the position corresponding to the energy data on the AC cable is an abnormal vibration position, and the abnormal condition includes that the number of the energy data exceeding the energy threshold among the multiple energy data collected at a certain position of the AC cable exceeds the proportion threshold;

[0014] Among them, the AC cable is a single-phase cable, and the n differential phase data are divided into multiple groups of signal data according to the time sequence of the vibration signal returned in the AC cable. The vibration signal is sampled again according to the time window of the time series, and the sampling frequency is twice the transmission frequency, and the n signals are divided into multiple groups of signal data.

[0015] In one embodiment, the lower limit of the preset vibration sampling frequency is the power frequency of the AC cable transmission; and / or,

[0016] The upper limit of the preset vibration sampling frequency Wherein, L is the length of the optical fiber in the AC cable, in km, C is the propagation speed of light in the optical fiber medium based on distributed acoustic wave sensing vibration monitoring, in km / s; and / or,

[0017] The AC cable is a single-phase submarine cable used for transmitting high-voltage AC power.

[0018] In one embodiment, the energy data is the total energy value in the frequency range of 2 Hz to 25 Hz in a spectrum diagram obtained by Fourier transforming the differential phase data after unwinding at different positions of the AC cable.

[0019] In one embodiment, the energy threshold is an upper limit value of the energy data calculated based on the spectrum diagram, and the ratio threshold is an upper limit value of the proportion of the number of energy data collected at a certain position of the AC cable that exceeds the energy threshold.

[0020] In one embodiment, the method further comprises:

[0021] Constructing a vibration signature diagram, wherein the horizontal axis of the vibration signature diagram is the position of the AC cable and the vertical axis is time;

[0022] According to the image recognition algorithm, the abnormal vibration position is identified from the vibration mark image and an early warning is issued, and the color attribute information of the abnormal vibration position is different from that of other positions.

[0023] In a second aspect, the present application also provides a cable abnormal vibration monitoring device based on distributed acoustic wave sensing, the device comprising:

[0024] A monitoring module, used for obtaining vibration signals of AC cables based on distributed acoustic wave sensing vibration monitoring;

[0025] A sampling module, used to sample the vibration signal according to a preset vibration sampling frequency to obtain a sampling signal, wherein the preset vibration sampling frequency is an integer multiple of the power frequency of the AC cable transmission;

[0026] A judgment module, used to demodulate the n sampling signals collected in time sequence according to a phase demodulation algorithm to obtain the phase of the sampling signal at each position of the AC cable;

[0027] Starting from the head end of the AC cable, the phases of any two positions on the AC cable that meet the differential distance are subtracted to obtain n differential phase data, where the differential distance is determined according to the required spatial resolution;

[0028] Dividing n differential phase data into multiple groups of signal data according to the time sequence of the vibration signal returning in the AC cable, and performing phase unwrapping on each group of signal data in the time domain to obtain multiple groups of unwrapped differential phase data;

[0029] The differential phase data after unwinding at different positions of the AC cable are respectively transformed into frequency spectra through Fourier transformation to calculate the energy data;

[0030] When the energy data at a certain position on the AC cable meets an abnormal condition, the position corresponding to the energy data on the AC cable is an abnormal vibration position, and the abnormal condition includes that the number of the energy data exceeding the energy threshold among the multiple energy data collected at a certain position of the AC cable exceeds the proportion threshold;

[0031] Among them, the AC cable is a single-phase cable, and the n differential phase data are divided into multiple groups of signal data according to the time sequence of the vibration signal returned in the AC cable. The vibration signal is sampled again according to the time window of the time series, and the sampling frequency is twice the transmission frequency, and the n signals are divided into multiple groups of signal data.

[0032] In one embodiment, the lower limit of the preset vibration sampling frequency is the power frequency of the AC cable transmission; and / or,

[0033] The upper limit of the preset vibration sampling frequency Wherein, L is the length of the optical fiber in the AC cable, in km, C is the propagation speed of light in the optical fiber medium based on distributed acoustic wave sensing vibration monitoring, in km / s; and / or,

[0034] The AC cable is a single-phase submarine cable used for transmitting high-voltage AC power.

[0035] In one embodiment, the energy data is the total energy value in the frequency range of 2 Hz to 25 Hz in a spectrum diagram obtained by Fourier transforming the differential phase data after unwinding at different positions of the AC cable.

[0036] In one embodiment, the energy threshold is an upper limit value of the energy data calculated based on the spectrum diagram, and the ratio threshold is an upper limit value of the proportion of the number of energy data collected at a certain position of the AC cable that exceeds the energy threshold.

[0037] In one embodiment, the device further comprises:

[0038] Constructing a vibration signature diagram, wherein the horizontal axis of the vibration signature diagram is the position of the AC cable and the vertical axis is time;

[0039] According to the image recognition algorithm, the abnormal vibration position is identified from the vibration mark image and an early warning is issued, and the color attribute information of the abnormal vibration position is different from that of other positions.

[0040] In a third aspect, the present disclosure further provides a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the AC cable abnormal vibration monitoring method based on distributed acoustic wave sensing are implemented.

[0041] In a fourth aspect, the present disclosure further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a method for monitoring abnormal vibration of an AC cable based on distributed acoustic wave sensing.

[0042] In a fifth aspect, the present disclosure further provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, the steps of the method for monitoring abnormal vibration of an AC cable based on distributed acoustic wave sensing are implemented.

[0043] The above-mentioned AC cable abnormal vibration monitoring method based on distributed acoustic wave sensing has at least the following beneficial effects:

[0044] After sampling the vibration signal based on the preset vibration sampling frequency, the vibration signal can be sampled again, and the abnormal vibration position of the AC cable can be determined based on the data analysis results of the sampled signal. Among them, the sampling frequency of the re-sampling is twice the power frequency of the AC cable transmission, which can eliminate the influence of the power frequency vibration during the AC cable transmission, and ensure that the sampling signal can be analyzed normally in the future to obtain the location of the vibration event. And multiple samplings are performed, and the joint judgment based on multiple sets of energy data can improve the accuracy of detecting the abnormal vibration position.

[0045] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 A diagram of an application environment of an AC cable abnormal vibration monitoring method based on distributed acoustic wave sensing in one embodiment;

[0048] Figure 2 It is a schematic diagram of a flow chart of a method for monitoring abnormal vibration of an AC cable based on distributed acoustic wave sensing in one embodiment;

[0049] Figure 3 is a schematic diagram of the operation of a distributed acoustic wave sensing system in one embodiment;

[0050] Figure 4 It is a schematic diagram of a flow chart of a method for monitoring abnormal vibration of an AC cable based on distributed acoustic wave sensing in one embodiment;

[0051] Figure 5 is a vibration signature diagram in one embodiment;

[0052] Figure 6 is a structural block diagram of an AC cable abnormal vibration monitoring device based on distributed acoustic wave sensing in one embodiment;

[0053] Figure 7 is an internal structure diagram of a computer device in one embodiment;

[0054] Figure 8 The figure is a diagram of the internal structure of a server in one embodiment. DETAILED DESCRIPTION

[0055] In order to enable ordinary persons in the art to better understand the technical solutions of the present disclosure, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings.

[0056] It should be noted that the terms "first", "second", etc. in the specification and claims of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present disclosure described here can be implemented in an order other than those illustrated or described here. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. On the contrary, they are only examples of devices and methods consistent with some aspects of the present disclosure as detailed in the attached claims. The terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, product or device including a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also includes elements inherent to such process, method, product or device. In the absence of more restrictions, it is not excluded that there are other identical or equivalent elements in the process, method, product or device including the elements. For example, if the words first, second, etc. are used to represent the name, they do not represent any specific order.

[0057] Submarine cables are an important carrier for ocean power transmission. With the rapid development of island economy, the number of submarine cables laid is increasing. At the same time, the frequency of problems with submarine cables is also increasing.

[0058] In related technologies, distributed acoustic wave sensors can be used to monitor the vibration state of submarine cables, and to provide early warning of certain submarine cable failure threats, such as when the submarine cable is caught by an anchor, and to locate some existing faults. The length of submarine cables is generally tens of kilometers, and many distributed optical fiber sensing products use balanced detection technology and digital demodulation algorithms to detect and process Rayleigh scattering signals and restore vibration waveforms. The advantage is that the measured signal can be amplified, the detection range is longer, and it can meet the monitoring needs of the entire submarine cable.

[0059] If a demodulation error occurs in the distributed fiber optic sensing product, the DAS (distributed acoustic sensor) will be unable to detect abnormal vibrations. For example, it will be unable to distinguish between vibration signals generated by actions such as anchors hanging on submarine cables and ocean currents, and thus will be unable to detect threats in a timely manner.

[0060] After a long period of research, the applicant found that there are many problems that lead to vibration demodulation errors. Therefore, how to avoid or weaken the monitoring and demodulation errors of distributed optical fiber sensors to reduce false alarms and improve monitoring accuracy has become an urgent problem to be solved. Among them, the problem of vibration demodulation errors is relatively common in cables that transmit alternating current, especially high-voltage alternating current, and this problem has plagued people in the industry. After a long period of research, the applicant found that the main reason for the monitoring and demodulation errors of distributed optical fiber sensors is the influence of the power frequency vibration of the cable itself, which causes the vibration signal detected by the distributed optical fiber sensor to contain signal interference, affecting the monitoring system's judgment of the cable status, and thus generating false alarms.

[0061] Based on the above problems and reasons, the applicant provides an abnormal vibration monitoring method of AC cables based on distributed acoustic wave sensing in the embodiments of the present disclosure, which can be applied to Figure 1 In the application environment shown, where the length of the submarine cable is generally tens of kilometers, sensors and other products can be used to adopt balanced detection technology and digital demodulation algorithms to detect and process Rayleigh scattering signals, restore vibration waveforms, and monitor the vibration of the entire submarine cable.

[0062] In some embodiments of the present disclosure, Figure 2 As shown, a method for monitoring abnormal vibration of an AC cable based on distributed acoustic wave sensing is provided. In a specific embodiment, the method may include the following steps:

[0063] S202: Obtain vibration signals of the AC cable based on distributed acoustic wave sensing vibration monitoring.

[0064] Figure 3 The figure is a schematic diagram of the operation of a distributed fiber optic acoustic wave sensing system in one embodiment. The laser emits a light pulse along the optical fiber. After the light pulse enters the optical fiber, the optical path of the optical fiber at that location changes because the optical fiber may be affected by an external acoustic wave signal or a vibration event, thereby affecting the interference result of the scattered light at that location, and further changing the amplitude of the scattered light at that location. The Rayleigh scattering signal detected by the signal processing device is the vibration signal of the AC cable.

[0065] S204: Sampling the vibration signal according to a preset vibration sampling frequency to obtain a sampling signal, wherein the preset vibration sampling frequency is an integer multiple of the power frequency of the AC cable transmission.

[0066] The power frequency may refer to the rated frequency used by the power generation, transmission, transformation and distribution equipment of the power system, as well as industrial and civil electrical equipment. A preset vibration sampling frequency may be set to sample the vibration signal. The preset vibration sampling frequency may be set to an integer multiple of the AC cable transmission. When the AC cable is transmitting power, the AC cable may have inherent vibration, which exceeds the upper limit of the measurement of the distributed acoustic wave sensor and causes the subsequent erroneous demodulation of the abnormal vibration position of the AC cable.

[0067] S206: demodulating the n sampling signals collected in time sequence respectively according to a phase demodulation algorithm to obtain the phase of the sampling signal at each position of the AC cable;

[0068] Starting from the head end of the AC cable, the phases of any two positions on the AC cable that meet the differential distance are subtracted to obtain n differential phase data, where the differential distance is determined according to the required spatial resolution;

[0069] Dividing n differential phase data into multiple groups of signal data according to the time sequence of the vibration signal returning in the AC cable, and performing phase unwrapping on each group of signal data in the time domain to obtain multiple groups of unwrapped differential phase data;

[0070] The differential phase data after unwinding at different positions of the AC cable are respectively transformed into frequency spectra through Fourier transformation to calculate the energy data;

[0071] When the energy data at a certain position on the AC cable meets an abnormal condition, the position corresponding to the energy data on the AC cable is an abnormal vibration position, and the abnormal condition includes that the number of the energy data exceeding the energy threshold among the multiple energy data collected at a certain position of the AC cable exceeds the proportion threshold;

[0072] Among them, the AC cable is a single-phase cable, and the n differential phase data are divided into multiple groups of signal data according to the time sequence of the vibration signal returned in the AC cable. The vibration signal is sampled again according to the time window of the time series, and the sampling frequency is twice the transmission frequency, and the n signals are divided into multiple groups of signal data.

[0073] in, Figure 4 The figure is a flow chart of a method for monitoring abnormal vibration of an AC cable based on distributed acoustic wave sensing in one embodiment.

[0074] S402: Demodulate the n sampling signals collected in time sequence according to a phase demodulation algorithm to obtain the phase of the sampling signal at each position of the AC cable.

[0075] Optical pulses can be emitted into the AC cable multiple times to obtain n returned Rayleigh scattered signals. The n Rayleigh scattered signals are numbered in the order of their return time, and the Rayleigh scattered signals are sampled according to the preset sampling frequency to obtain n sampled signals. After the optical pulse enters the AC cable, the external acoustic wave signal causes the phase of the backward Rayleigh scattered light in the optical fiber to change, and the phase at each position of the AC cable can be demodulated using a phase demodulation algorithm.

[0076] S404: starting from the head end of the AC cable, subtract the phases of any two positions on the AC cable that meet the differential distance to obtain n differential phase data, where the differential distance is determined according to the required spatial resolution.

[0077] Spatial resolution refers to the minimum distance on the optical fiber that can distinguish different vibration events in detail, and can indicate the positioning accuracy of the distributed acoustic wave sensor for the abnormal vibration position of the AC cable. For example, when the length of the AC cable is less than the spatial resolution, the sampled signal may be aliased, and the abnormal vibration position cannot be obtained by data analysis based on the sampled signal.

[0078] The differential distance can be expressed as the position difference between any two positions on the AC cable when the phases of any two positions on the AC cable are subtracted. The size of the differential distance can be determined according to the spatial resolution. For example, the larger the spatial resolution, the larger the differential distance can be.

[0079] S406: Divide the n differential phase data into multiple groups of signal data according to the time sequence of the vibration signal returning in the AC cable, and perform phase unwrapping on each group of the signal data in the time domain to obtain multiple groups of unwrapped differential phase data.

[0080] The phase measured by distributed acoustic wave sensing may not be the real phase, but the result of the real phase modulo 2π, which causes the real phase to differ from the measured phase by an integer multiple of 2π, which may cause phase wrapping problems. At this time, the signal waveform will show folding and jumping. The signal data can be phase unwrapped to show a state of monotonic change of the signal waveform. Multiple differential phase data can be divided into multiple groups in chronological order to obtain multiple groups of unwrapped differential phase data.

[0081] The use of differential phase data can well reflect changes in the external environment, and the differential phase data can change synchronously with external vibrations.

[0082] S408: Obtain frequency spectra of the unwound differential phase data at different positions of the AC cable through Fourier transformation to calculate the energy data.

[0083] In the previous operation, n differential phases are divided into m groups according to the time label. For example, the frequency of collecting the vibration signal of the AC cable is 1000 Hz, and 1000 signals can be collected for 1 second. The vibration signal is sampled again according to the time window of the time series. If the sampling frequency is 50 Hz, the 1000 signals are divided into 20 groups, each with 50 signals. Fourier transform can convert the time domain signal into the frequency domain signal, obtain the spectrum diagram, and calculate multiple groups of energy data.

[0084] When AC cables are used for marine power transmission, abnormal vibrations may include vibration signals generated by ocean current scouring, anchor hanging events, etc. Different vibration signals generate different energy data, and abnormal conditions can be set. If the energy data at a certain position on the AC cable meets the abnormal conditions, the corresponding position of the energy data on the AC cable is the abnormal vibration position. In the case of collecting multiple energy data, the abnormal condition can be that the number of energy data collected at a certain position of the AC cable that exceeds the energy threshold exceeds the proportion threshold, where the energy threshold and the proportion threshold can be determined according to changes in the external environment.

[0085] Data analysis can include balanced detection technology, digital demodulation algorithm, etc., to recover the vibration waveform of the sampled signal. Abnormal vibration can include vibration signals generated by ocean current scouring, anchor hanging events, etc. The results obtained through data analysis can obtain the abnormal vibration position of the AC cable.

[0086] In the above-mentioned AC cable abnormal vibration monitoring method based on distributed acoustic wave sensing, after sampling the vibration signal based on the preset vibration sampling frequency, the vibration signal can be sampled again, and the abnormal vibration position of the AC cable can be determined according to the data analysis result of the sampled signal. Among them, the sampling frequency of the re-sampling is one times the power frequency of the AC cable transmission, which can eliminate the influence of the power frequency vibration during the AC cable transmission, and ensure that the sampling signal can be analyzed normally in the future to obtain the position of the vibration event.

[0087] In some embodiments of the present disclosure, the lower limit of the preset vibration sampling frequency is the power frequency of the AC cable transmission; and / or,

[0088] The upper limit of the preset vibration sampling frequency Wherein, L is the length of the optical fiber in the AC cable, in km, C is the propagation speed of light in the optical fiber medium based on distributed acoustic wave sensing vibration monitoring, in km / s; and / or,

[0089] The AC cable is a single-phase submarine cable used for transmitting high-voltage AC power.

[0090] The preset vibration sampling frequency can be set to an integer multiple of the power frequency of the AC cable transmission. The higher the preset vibration sampling frequency, the closer the collected signal is to the real signal. Setting the upper limit of the vibration sampling frequency is to set the lower limit of the sampling period. Setting the upper limit of the vibration sampling frequency can ensure that the sensor can collect a complete round trip light pulse in the AC cable. Where L is the length of the optical fiber in the AC cable, that is, the one-way distance of a light pulse in the optical fiber. For example, Figure 3It can be expressed as the distance of the light pulse from point a to point b in the optical fiber, in km. C is the propagation speed of light in the optical fiber medium based on distributed acoustic wave sensing vibration monitoring, in km / s, and the upper limit of the preset vibration sampling frequency The lower limit of the preset vibration sampling frequency may be the power frequency of the AC cable power transmission, ensuring that the preset vibration sampling frequency is an integer multiple of the power frequency of the AC cable power transmission.

[0091] In some embodiments of the present disclosure, the energy data is the total energy value within the frequency range of 2 Hz to 25 Hz in a spectrum diagram obtained by Fourier transforming the differential phase data after unwinding at different positions of the AC cable.

[0092] The purpose of this scheme is to find abnormal vibration signals. The detected signals include not only anchor signals but also signals generated by wave impact. The applicant further analyzed and found that the signals of wave impact are generally below 2 Hz, and the frequencies of most abnormal vibration signals are distributed between 2 Hz and 25 Hz. Therefore, energy data in the range of 2 Hz to 25 Hz can be selected for analysis, wherein the energy data is the total energy value in the frequency range of 2 Hz to 25 Hz in the spectrum diagram obtained by Fourier transform of the differential phase data after unwinding at different positions of the AC cable, so as to improve the efficiency of monitoring the abnormal vibration position.

[0093] In some embodiments of the present disclosure, the energy threshold is an upper limit value of the energy data calculated based on the spectrum diagram, and the proportion threshold is an upper limit value of the proportion of the number of energy data collected at a certain position of the AC cable that exceeds the energy threshold.

[0094] The relationship between frequency and amplitude can be intuitively observed from the spectrum graph, and then the energy data can be calculated. The selection of energy threshold and proportional threshold can be determined according to the actual interference of the seabed. The seabed interference can be intuitively displayed on the spectrum graph to reduce false alarms caused by changes in the seabed interference situation and further improve accuracy. If the actual seabed interference is strong, the proportion of the proportional threshold is increased. If the actual seabed interference is weak, the proportion of the proportional threshold is reduced. The use of multiple sets of energy data for joint judgment can improve the accuracy of detecting abnormal vibration locations.

[0095] In some embodiments of the present disclosure, the method further includes:

[0096] Constructing a vibration signature diagram, wherein the horizontal axis of the vibration signature diagram is the position of the cable and the vertical axis is time;

[0097] According to the image recognition algorithm, the abnormal vibration position is identified from the vibration mark image and an early warning is issued, and the color attribute information of the abnormal vibration position is different from that of other positions.

[0098] Figure 5 It is a vibration marking diagram in an embodiment, wherein the horizontal axis represents the position of the AC cable and the vertical axis represents time. If the proportion of the energy threshold of a certain position of the AC cable exceeds the proportion threshold, the vibration of the current time of the position of the AC cable can be marked as 1, indicating that an anchoring event may occur, otherwise it is marked as 0. Black represents a vibration marking value of 1, and white represents a vibration marking value of 0. An image recognition algorithm can be used to identify anchoring events from images and issue an early warning. The characteristic of an anchoring event is that the black and white graph of the vibration marking value presents a trapezoidal distribution along the time axis, the short side of the trapezoid is the front moment, and the long side of the trapezoid is the back moment. The position of the AC cable is arranged from left to right on the axis.

[0099] It should be understood that, although the various steps in the flowcharts involved in the above-mentioned embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above-mentioned embodiments can include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0100] Based on the same inventive concept, the embodiment of the present disclosure also provides a cable abnormal vibration monitoring device based on distributed acoustic wave sensing for implementing the above-mentioned cable abnormal vibration monitoring method based on distributed acoustic wave sensing. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above-mentioned method, so the specific limitations in the embodiment of the cable abnormal vibration monitoring device based on distributed acoustic wave sensing provided below can refer to the limitations of the cable abnormal vibration monitoring method based on distributed acoustic wave sensing above, and will not be repeated here.

[0101] The device may include a system (including a distributed system), software (application), module, component, server, client, etc. using the method described in the embodiments of this specification and a device in combination with necessary implementation hardware. Based on the same innovative concept, the device in one or more embodiments provided in the embodiments of the present disclosure is as described in the following embodiments. Since the implementation scheme and method for solving the problem of the device are similar, the implementation of the specific device in the embodiments of this specification can refer to the implementation of the aforementioned method, and the repetitions will not be repeated. As used below, the term "unit" or "module" can implement a combination of software and / or hardware for predetermined functions. Although the device described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceived.

[0102] In one embodiment, Figure 6 As shown, a cable abnormal vibration monitoring device 600 based on distributed acoustic wave sensing is provided, and the device may be the aforementioned server, or a module, component, device, unit, etc. integrated in the server. The device 600 may include:

[0103] A monitoring module 602 is used to obtain a vibration signal of the AC cable based on distributed acoustic wave sensing vibration monitoring;

[0104] The sampling module 604 is used to sample the vibration signal according to a preset vibration sampling frequency to obtain a sampling signal, wherein the preset vibration sampling frequency is an integer multiple of the power frequency of the AC cable transmission;

[0105] The judgment module 606 is used to demodulate the n sampling signals collected in time sequence according to the phase demodulation algorithm to obtain the phase of the sampling signal at each position of the AC cable;

[0106] Starting from the head end of the AC cable, the phases of any two positions on the AC cable that meet the differential distance are subtracted to obtain n differential phase data, where the differential distance is determined according to the required spatial resolution;

[0107] Dividing n differential phase data into multiple groups of signal data according to the time sequence of the vibration signal returning in the AC cable, and performing phase unwrapping on each group of signal data in the time domain to obtain multiple groups of unwrapped differential phase data;

[0108] The differential phase data after unwinding at different positions of the AC cable are respectively transformed into frequency spectra through Fourier transformation to calculate the energy data;

[0109] When the energy data at a certain position on the AC cable meets an abnormal condition, the position corresponding to the energy data on the AC cable is an abnormal vibration position, and the abnormal condition includes that the number of the energy data exceeding the energy threshold among the multiple energy data collected at a certain position of the AC cable exceeds the proportion threshold;

[0110] Among them, the AC cable is a single-phase cable, and the n differential phase data are divided into multiple groups of signal data according to the time sequence of the vibration signal returned in the AC cable. The vibration signal is sampled again according to the time window of the time series, and the sampling frequency is twice the transmission frequency, and the n signals are divided into multiple groups of signal data.

[0111] In one embodiment, the lower limit of the preset vibration sampling frequency is the power frequency of the AC cable transmission; and / or,

[0112] The upper limit of the preset vibration sampling frequency Wherein, L is the length of the optical fiber in the AC cable, in km, C is the propagation speed of light in the optical fiber medium based on distributed acoustic wave sensing vibration monitoring, in km / s; and / or,

[0113] The AC cable is a single-phase submarine cable used for transmitting high-voltage AC power.

[0114] In one embodiment, the energy data is the total energy value in the frequency range of 2 Hz to 25 Hz in a spectrum diagram obtained by Fourier transforming the differential phase data after unwinding at different positions of the AC cable.

[0115] In one embodiment, the energy threshold is an upper limit value of the energy data calculated based on the spectrum diagram, and the ratio threshold is an upper limit value of the proportion of the number of energy data collected at a certain position of the AC cable that exceeds the energy threshold.

[0116] In one embodiment, the device further comprises:

[0117] Constructing a vibration signature diagram, wherein the horizontal axis of the vibration signature diagram is the position of the AC cable and the vertical axis is time;

[0118] According to the image recognition algorithm, the abnormal vibration position is identified from the vibration mark image and an early warning is issued, and the color attribute information of the abnormal vibration position is different from that of other positions.

[0119] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0120] Each module in the above-mentioned cable abnormal vibration monitoring device based on distributed acoustic wave sensing can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above-mentioned modules can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in a computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0121] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Figure 7 As shown. The computer device includes a processor, a memory and a network interface connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store sampled signals. The network interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a cable abnormal vibration monitoring method based on distributed acoustic wave sensing is implemented.

[0122] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Figure 8 As shown. The computer device includes a processor, a memory, a communication interface, a display screen and an input device connected through a system bus. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a cable abnormal vibration monitoring method based on distributed acoustic wave sensing is implemented. The display screen of the computer device can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covered on the display screen, or a button, a trackball or a touch pad set on the computer device housing, or an external keyboard, touch pad or mouse, etc.

[0123] Those skilled in the art will understand that Figure 7 , Figure 8The structure shown in the figure is only a block diagram of a part of the structure related to the scheme of the present disclosure, and does not constitute a limitation on the computer device to which the scheme of the present disclosure is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0124] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the method described in any embodiment of the present disclosure is implemented.

[0125] In one embodiment, a computer program product is provided, including a computer program, which implements the method described in any embodiment of the present disclosure when executed by a processor.

[0126] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided by the present disclosure can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided by the present disclosure may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited thereto. The processor involved in each embodiment provided by the present disclosure may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited thereto.

[0127] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0128] The above-described embodiments only express several implementation methods of the present disclosure, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present disclosure, and these all belong to the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the attached claims.

Claims

1. A method for monitoring abnormal vibration of AC cables based on distributed acoustic wave sensing, characterized in that: The method comprises: Based on distributed acoustic wave sensing vibration monitoring, the vibration signal of AC cable is obtained; Sampling the vibration signal according to a preset vibration sampling frequency to obtain a sampling signal, wherein the preset vibration sampling frequency is an integer multiple of the power frequency of the AC cable transmission; Demodulate the n sampling signals collected in time sequence respectively according to a phase demodulation algorithm to obtain the phase of the sampling signal at each position of the AC cable; Starting from the head end of the AC cable, the phases of any two positions on the AC cable that meet the differential distance are subtracted to obtain n differential phase data, where the differential distance is determined according to the required spatial resolution; Dividing n differential phase data into multiple groups of signal data according to the time sequence of the vibration signal returning in the AC cable, and performing phase unwrapping on each group of signal data in the time domain to obtain multiple groups of unwrapped differential phase data; The differential phase data after unwinding at different positions of the AC cable are respectively transformed into frequency spectra through Fourier transformation to calculate the energy data; When the energy data at a certain position on the AC cable meets an abnormal condition, the position corresponding to the energy data on the AC cable is an abnormal vibration position, and the abnormal condition includes that the number of the energy data exceeding the energy threshold among the multiple energy data collected at a certain position of the AC cable exceeds the proportion threshold; Among them, the AC cable is a single-phase cable, and the n differential phase data are divided into multiple groups of signal data according to the time sequence of the vibration signal returned in the AC cable. The vibration signal is sampled again according to the time window of the time series, and the sampling frequency is twice the transmission frequency, and the n signals are divided into multiple groups of signal data.

2. The method according to claim 1, characterized in that The lower limit of the preset vibration sampling frequency is the power frequency of the AC cable transmission; and / or, The upper limit of the preset vibration sampling frequency Wherein, L is the length of the optical fiber in the AC cable, in km, C is the propagation speed of light in the optical fiber medium based on distributed acoustic wave sensing vibration monitoring, in km / s; and / or, The AC cable is a single-phase submarine cable used for transmitting high-voltage AC power.

3. The method according to claim 1, characterized in that: The energy data is the total energy value within the frequency range of 2 Hz to 25 Hz in the spectrum diagram obtained by Fourier transforming the differential phase data after unwinding at different positions of the AC cable.

4. The method according to claim 1, characterized in that: The energy threshold is an upper limit value of the energy data calculated according to the spectrum diagram, and the ratio threshold is an upper limit value of the proportion of the number of energy data collected at a certain position of the AC cable that exceeds the energy threshold.

5. The method according to claim 1, characterized in that The method further comprises: Constructing a vibration signature diagram, wherein the horizontal axis of the vibration signature diagram is the position of the AC cable and the vertical axis is time; According to the image recognition algorithm, the abnormal vibration position is identified from the vibration mark image and an early warning is issued, and the color attribute information of the abnormal vibration position is different from that of other positions.

6. An AC cable abnormal vibration monitoring device based on distributed acoustic wave sensing, characterized in that: The device comprises: A monitoring module, used for obtaining vibration signals of AC cables based on distributed acoustic wave sensing vibration monitoring; A sampling module, used to sample the vibration signal according to a preset vibration sampling frequency to obtain a sampling signal, wherein the preset vibration sampling frequency is an integer multiple of the power frequency of the AC cable transmission; A judgment module, used to demodulate the n sampling signals collected in time sequence according to a phase demodulation algorithm to obtain the phase of the sampling signal at each position of the AC cable; Starting from the head end of the AC cable, the phases of any two positions on the AC cable that meet the differential distance are subtracted to obtain n differential phase data, where the differential distance is determined according to the required spatial resolution; Dividing n differential phase data into multiple groups of signal data according to the time sequence of the vibration signal returning in the AC cable, and performing phase unwrapping on each group of signal data in the time domain to obtain multiple groups of unwrapped differential phase data; The differential phase data after unwinding at different positions of the AC cable are respectively transformed into frequency spectra through Fourier transformation to calculate the energy data; When the energy data at a certain position on the AC cable meets an abnormal condition, the position corresponding to the energy data on the AC cable is an abnormal vibration position, and the abnormal condition includes that the number of the energy data exceeding the energy threshold among the multiple energy data collected at a certain position of the AC cable exceeds the proportion threshold; Among them, the AC cable is a single-phase cable, and the n differential phase data are divided into multiple groups of signal data according to the time sequence of the vibration signal returned in the AC cable. The vibration signal is sampled again according to the time window of the time series, and the sampling frequency is twice the transmission frequency, and the n signals are divided into multiple groups of signal data.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 5 are implemented.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

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