Method and device for monitoring periodic galloping of OPGW (Optical Fiber Composite Overhead Ground Wire) tower
Through vibration phase demodulation and Hilbert transformation technology, the influence of optical fiber sensing technology in OPGW tower dance monitoring is solved, and higher quality signal processing and more accurate dance monitoring is achieved, supporting the safe operation and maintenance of optical cables.
Patent Information
- Application Number
- CN202311850045.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-29
- Publication Date
- 2025-07-25
AI Technical Summary
When monitoring the dancing of the OPGW pole tower, existing fiber optic sensing technology is susceptible to environmental factors such as temperature and humidity, resulting in inaccurate monitoring data, especially the noise influence of the dancing signal in the low-frequency band is difficult to effectively reduce.
The phase signal of the monitoring signal is calculated by using the vibration phase demodulation method, and then the signal is constructed and Hilbert transform is performed. The signal is decomposed into a modal function, high-frequency noise is identified and filtered out, and the denoised monitoring signal is recombined.
It improves signal quality, increases monitoring accuracy, can more accurately reflect the dancing status of the OPGW pole tower, and supports the safe operation and maintenance strategies of optical cables.
Smart Images
Figure CN120369090A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of OPGW tower monitoring, and particularly to a method and device for periodic galloping monitoring of OPGW towers. Background Art
[0002] Optical fiber composite overhead ground wire (OPGW) plays a key role in the power system, and its galloping state is directly related to the safety of the power system. Therefore, it is crucial to monitor the galloping of OPGW in real time.
[0003] Currently, for OPGW galloping monitoring based on optical fiber sensing technology, optical time domain reflectometry (OTDR) technology and optical coherence scattering (OCS) technology are mainly used. The OTDR technology monitors the galloping state by measuring the reflection signal in the optical fiber, which has the advantages of a wide measurement range and high accuracy, but is greatly affected by the environment; while the OCS technology monitors the galloping state by measuring the scattering signal in the optical fiber, which has the advantages of high measurement accuracy and little influence from the environment, but its measurement range is limited. From the perspective of practical applications, the monitoring data of optical fiber sensing technology is easily affected by environmental factors such as temperature and humidity.
[0004] In order to reduce the influence of environmental factors on optical fiber sensing technology, researchers have developed various noise reduction methods. Among them, data fusion technology improves the accuracy and stability of measurement, but has higher hardware requirements and deployment complexity; the prediction model also predicts and eliminates the influence of noise, but for the galloping monitoring line in a specific environment, it is relatively difficult to establish the model; data smoothing processing effectively eliminates random noise, but for the galloping signal in the low-frequency band, how to effectively reduce the influence of noise is still a major challenge in galloping monitoring. Summary of the Invention
[0005] The purpose of this application is to overcome the above technical problems in the prior art and provide a method and device for periodic galloping monitoring of OPGW towers.
[0006] This application provides a method for periodic galloping monitoring of OPGW towers, including:
[0007] Obtaining a monitoring signal of the periodic galloping of the OPGW tower;
[0008] Calculating the phase signal of a single said monitoring signal based on the vibration phase demodulation method;
[0009] Composing the phase signals into a signal matrix according to the space and number sequence of the monitoring signals;
[0010] Performing a Hilbert transform on the signal matrix to convert the real signal into a complex signal;
[0011] Decomposing the complex signal into modal functions;
[0012] Identify and filter out the part of the modal function containing high-frequency noise;
[0013] Recombine the modal functions after noise filtering to obtain the OPGW tower periodic galloping monitoring signal after denoising.
[0014] Optionally, calculate the phase signal of a single said monitoring signal based on the vibration phase demodulation method, including: The phase signal obtained by the i-th sensor at the j-th sampling point is:
[0015]
[0016] wherein, is the phase change amount caused by the optical cable galloping, is the initial phase, f0 is the galloping period, and S is the sampling rate.
[0017] Optionally, perform a Hilbert transform on the signal matrix, and the expression is as follows:
[0018]
[0019] wherein, mi(t) is the modal component inherent in the array, and rn(t) is the residual component.
[0020] Optionally, obtain the monitoring signal of the OPGW tower periodic galloping, including:
[0021] After the laser emits pulsed light, it enters the grating array of the OPGW line through the first circulator and continues to enter the unbalanced interferometer through the second circulator to realize the measurement of the monitoring signal.
[0022] Optionally, the laser includes: a narrow linewidth laser.
[0023] This application also provides an OPGW tower periodic galloping monitoring device, including:
[0024] An acquisition module for acquiring the monitoring signal of the OPGW tower periodic galloping;
[0025] A phase module for calculating the phase signal of a single said monitoring signal based on the vibration phase demodulation method;
[0026] A matrix module for forming the phase signals into a signal matrix according to the spatial and numbering order of the monitoring signals;
[0027] A transformation module for performing a Hilbert transform on the signal matrix to convert the real signal into a complex signal;
[0028] A decomposition module for decomposing the complex signal into modal functions;
[0029] A filtering module, configured to identify and filter out the part of the mode function containing high-frequency noise;
[0030] A combining module, configured to recombine the mode functions after noise filtering to obtain a denoised OPGW tower periodic galloping monitoring signal.
[0031] Optionally, the phase module calculates the phase signal of a single monitoring signal based on a vibration phase demodulation method, including: the phase signal obtained by the i-th sensor at the j-th sampling point is:
[0032]
[0033] where is the phase change amount caused by optical cable galloping, is the initial phase, f0 is the galloping period, and S is the sampling rate.
[0034] Optionally, the transformation module performs a Hilbert transform on the signal matrix, and the expression is as follows:
[0035]
[0036] where m i (t) is the modal component inherent in the array, and r n (t) is the residual component.
[0037] Optionally, the acquisition module acquires the monitoring signal of the OPGW tower periodic galloping, including:
[0038] After the laser emits pulsed light, it enters the grating array of the OPGW line through the first circulator, and then continues to enter the unbalanced interferometer through the second circulator to realize the measurement of the monitoring signal.
[0039] Optionally, the laser includes: a narrow linewidth laser.
[0040] The beneficial effects of this application are:
[0041] This application provides an OPGW tower periodic galloping monitoring method, including: acquiring the monitoring signal of the OPGW tower periodic galloping; calculating the phase signal of a single monitoring signal based on the vibration phase demodulation method; forming the phase signals into a signal matrix according to the spatial and numbering order of the monitoring signals; performing a Hilbert transform on the signal matrix to convert the real signal into a complex signal; decomposing the complex signal into mode functions; identifying and filtering out the part of the mode function containing high-frequency noise; recombining the mode functions after noise filtering to obtain a denoised OPGW tower periodic galloping monitoring signal. This application improves the signal quality and increases the monitoring accuracy through phase noise reduction. Description of the Drawings
[0042] Figure 1 It is a schematic diagram of the OPGW tower periodic galloping monitoring process in this application;
[0043] Figure 2 It is a schematic diagram of the monitoring system for OPGW tower periodic galloping in this application;
[0044] Figure 3 It is a schematic diagram of the time-domain result of the galloping signal under high background noise in this application;
[0045] Figure 4 It is a schematic diagram of the signal decomposition result in this application;
[0046] Figure 5 It is a schematic diagram of the result of the galloping monitoring signal after noise reduction and reconstruction in this application. Specific embodiments
[0047] The following further describes this application with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand this application and implement it.
[0048] The following content is all examples of the specific implementation process provided to detail the technical solution to be protected by this application. However, this application can also be implemented in other ways different from the described ones. Under the guidance of the concept of this application, those skilled in the art can implement this application using different technical means. Therefore, this application is not limited by the following specific embodiments.
[0049] Please refer to Figure 1 As shown, the steps of a method for monitoring the periodic galloping of an OPGW tower include:
[0050] S101 Obtain the monitoring signal of the OPGW tower periodic galloping.
[0051] This application obtains the monitoring signal through an optical fiber sensor.
[0052] As Figure 2 shown. First, after a laser emits pulsed light, the pulsed light first passes through a circulator 1 (CIR1) and then enters a grating array (grating 1, grating 2,..., grating n) located on the OPGW line. During this process, the pulsed light is reflected by each grating, generating a pulse array. The pulse array continues to propagate and is guided to an unbalanced interferometer through circulator 2.
[0053] The design of this unbalanced interferometer is unique. The arm lengths of its two Faraday rotators, Faraday rotator 1 and Faraday rotator 2, are not equal. This design is called an unbalanced interferometer. When a pulse array passes through this unbalanced interferometer, the front and rear pulses achieve optical path matching, which means their optical path difference is precisely adjusted to zero. In this case, the front and rear pulses meet the conditions for two-beam interference and interfere with each other.
[0054] Once the interference conditions are met, interference measurement is carried out. Interference measurement is a technique that uses the interference phenomenon of waves to measure physical quantities and has extremely high measurement accuracy. In this system, by measuring the interference pattern, the state information of the OPGW line is inferred, including parameters such as the temperature, vibration, and current of the line.
[0055] In addition, to ensure the stability and reliability of the system, advanced optical components and precise optical path designs are adopted. Circulator 1 and circulator 2 not only ensure the propagation direction of light but also effectively isolate the input and output optical paths, avoiding optical interference. The ingenious design of the unbalanced interferometer enables the front and rear pulses to achieve optical path matching, thus ensuring the smooth progress of interference.
[0056] As Figure 3 shown, the time-domain results of the galloping signal under high background noise are presented, that is, the monitoring signal. By observing this time-domain graph, it can be clearly seen that the galloping signal waveform is distributed with dense pulses, which makes it impossible to accurately determine the period of the galloping signal. These dense pulses make the signal complex and difficult to analyze, increasing the difficulty of accurately interpreting the galloping signal.
[0057] S102 calculates the phase signal of a single said monitoring signal based on the vibration phase demodulation method.
[0058] By using various grating demodulation methods, the phase change amount of the sensor is obtained.
[0059] For the monitoring sensing gratings along the OPGW optical cable, each sensor will have a corresponding demodulation signal at a specific sampling point.
[0060] First, for the i-th sensor at the j-th sampling point, its demodulation signal is:
[0061]
[0062] where, is the phase change amount caused by the galloping of the optical cable; is the initial phase.
[0063] Considering that when the optical cable is galloping, the phase of each sensor is continuously changing, differential processing is performed on the demodulation signals at the front and rear moments. In this way, the obtained phase change amount is:
[0064]
[0065] However, for an on-line monitoring system with a sampling rate of S, when the phase change obtained by single differential is very small, it is difficult to obtain a stable monitoring and comparison result.
[0066] To solve this problem, accumulation is performed on the time scale to amplify the differential characteristics of the sensing array. The number of accumulations is related to the general dancing period f0 when the OPGW optical cable is dancing. After accumulating half a period, the differential phase of the i-th grating is:
[0067]
[0068] The mean value of the accumulated differential phase is calculated to smooth the obtained phase and suppress the intensity noise generated in a complex environment. The smoothed differential phase is expressed as:
[0069]
[0070] S103 forms a signal matrix with the phase signals in the order of the space and number of the monitoring signals.
[0071] At this time, for an array composed of N sensing units on the OPGW monitoring optical cable line, its phase is represented by a matrix:
[0072] [Φ i all =[Φ1 Φ2 Φ3 Φ4... Φ N ;
[0073] Among them, each element represents the phase of the i-th sensing unit.
[0074] To better analyze and visualize the dancing state of the optical cable, a dancing monitoring matrix of "phase change - sensor" is constructed. This matrix associates the phase change amount with the position of each sensor, thereby forming a two-dimensional signal intensity map.
[0075] Through this signal intensity map, the dancing law of the OPGW optical cable is further inversed. For example, by observing the periodic patterns or local anomalies on the signal intensity map, the dancing frequency and wavelength of the optical cable under the action of the environment are speculated.
[0076] S104 performs a Hilbert transform on the signal matrix to convert the real signal into a complex signal.
[0077] The obtained array phase is decomposed by Hilbert transform and expressed as the sum of multiple modal components and a residual component, that is:
[0078]
[0079] where m i (t) is the modal component inherent in the array, representing the variation of the array phase at different frequencies or modes. These modal components usually contain the main characteristics of the array phase and reflect the basic modes of the optical cable galloping. And r n (t) is the residual component, representing the part that cannot be fully explained by the modal component. This part usually contains phase changes caused by noise, non-linear effects or other complex factors. The magnitude and characteristics of the residual component provide information about the complexity and uncertainty of the optical cable galloping.
[0080] By performing Hilbert transform decomposition on the array phase, we can gain a deeper understanding of the dynamic characteristics of the optical cable galloping, including its main galloping modes, frequencies and amplitudes, etc. This helps to more accurately evaluate the galloping state of the optical cable, predict its future galloping behavior, and take effective measures to prevent the damage caused by galloping to the optical cable.
[0081] S105 decomposes the complex signal into modal functions.
[0082] As Figure 4 shown is the EMD decomposition result of the signal. From this result graph, it is impossible to visually identify the fault characteristics contained in the signal. However, since the energy of the galloping signal is mainly concentrated in the very low frequency band, useful information can be extracted by processing the decomposed signal. Specifically, the high-frequency part with low correlation is filtered out, and the remaining components are reconstructed, thus obtaining the denoised galloping monitoring signal.
[0083] Specifically, for the decomposed signal, different modal components are generated at each moment to analyze the characteristics of the signal in more depth.
[0084] First, focus on the amplitude fluctuations of the low-frequency part. The low-frequency component usually represents the basic mode or main trend of the optical cable galloping. By analyzing the amplitude changes of the low-frequency component, understand the intensity and periodicity of the optical cable galloping, and thus infer the possible causes and mechanisms of the galloping.
[0085] At the same time, in order to further improve the signal-to-noise ratio and accuracy of the signal, the high-frequency part needs to be processed. Specifically, the high-frequency components with low correlation will be filtered out. These high-frequency components often contain a large amount of noise and interference, which may have a negative impact on the accurate judgment of the optical cable galloping state.
[0086] S106 identifies the part of the modal function containing high-frequency noise and filters it out.
[0087] After noise filtering, a set of denoised Intrinsic Mode Functions (IMFs) is obtained. These IMFs represent the components of the OPGW galloping signal at different frequencies or modes and the high-frequency noise interference has been removed.
[0088] S107 recombines the mode functions after noise filtering to obtain the denoised OPGW tower periodic galloping monitoring signal.
[0089] As Figure 5 shown, the characteristics of the galloping signal are effectively extracted and highlighted. This indicates that the algorithm has a positive application prospect in galloping signal monitoring and is expected to provide strong support for research and applications in related fields.
[0090] To obtain the complete denoised OPGW galloping signal, these noise-filtered IMFs need to be recombined. This is achieved by superimposing each IMF according to its corresponding weight and time series.
[0091] The recombined signal will exhibit clearer and more accurate OPGW galloping characteristics. Since the high-frequency noise has been removed, this signal will be more capable of truly reflecting the galloping state of the optical cable, including the amplitude, frequency, and mode of galloping, etc.
[0092] By further analyzing and processing the denoised OPGW galloping signal, we can gain a deeper understanding of the dynamic characteristics of the optical cable galloping, including its main galloping modes, the variation of galloping intensity over time, etc. This will provide strong support for formulating effective optical cable galloping protection measures and optimizing optical cable maintenance and repair strategies.
[0093] Finally, through such processing and analysis, we will be able to comprehensively and accurately grasp the galloping state of the OPGW optical cable, providing strong technical support for ensuring the safe operation of the optical cable.
[0094] This application also provides an OPGW tower periodic galloping monitoring device, including:
[0095] An acquisition module for acquiring the monitoring signal of the OPGW tower periodic galloping;
[0096] A phase module for calculating the phase signal of a single said monitoring signal based on the vibration phase demodulation method;
[0097] A matrix module for forming a signal matrix with the phase signals in the order of the space and number of the said monitoring signals;
[0098] A transformation module for performing Hilbert transform on the said signal matrix to convert the real signal into a complex signal;
[0099] A decomposition module for decomposing the said complex signal into mode functions;
[0100] A filtering module, configured to identify and filter out the part of the modal function containing high-frequency noise;
[0101] A combining module, configured to recombine the modal functions after noise filtering to obtain a denoised OPGW tower periodic galloping monitoring signal.
[0102] Further, the phase module calculates the phase signal of a single said monitoring signal based on a vibration phase demodulation method, including: the phase signal obtained by the i-th sensor at the j-th sampling point is:
[0103]
[0104] wherein, is the phase change amount caused by optical cable galloping, is the initial phase, f0 is the galloping period, and S is the sampling rate.
[0105] Further, the transformation module performs a Hilbert transform on the signal matrix, and the expression is as follows:
[0106]
[0107] where m i (t) is the modal component inherent in the array, and r n (t) is the residual component.
[0108] Further, the acquisition module acquires the monitoring signal of the OPGW tower periodic galloping, including:
[0109] After the laser emits pulsed light, it enters the grating array of the OPGW line through the first circulator, and continues to enter the unbalanced interferometer through the second circulator to realize the measurement of the monitoring signal.
[0110] Further, the laser includes: a narrow linewidth laser.
Claims
1. A method for monitoring the periodic galloping of OPGW towers, characterized in that, Including: Obtaining the monitoring signal of the periodic galloping of the OPGW tower; Calculating the phase signal of a single said monitoring signal based on the vibration phase demodulation method; Composing the phase signals into a signal matrix according to the spatial and numbering order of the monitoring signals; Performing a Hilbert transform on the signal matrix to convert the real signal into a complex signal; Decomposing the complex signal into modal functions; Identifying and filtering out the part of the modal function containing high-frequency noise; Recombining the modal functions after noise filtering to obtain the denoised monitoring signal of the periodic galloping of the OPGW tower.
2. The OPGW tower periodic galloping monitoring method according to claim 1, wherein Calculating the phase signal of a single said monitoring signal based on the vibration phase demodulation method, including: The phase signal obtained by the i-th sensor at the j-th sampling point is: wherein, is the phase change amount caused by the galloping of the optical cable, is the initial phase, f0 is the galloping period, and S is the sampling rate.
3. The OPGW tower periodic galloping monitoring method according to claim 1, wherein Performing a Hilbert transform on the signal matrix, and the expression is as follows: Where, mi(t) is the modal component inherent in the array, and rn(t) is the residual component.
4. The OPGW tower periodic galloping monitoring method according to claim 1, wherein Obtaining the monitoring signal of the periodic galloping of the OPGW tower, including: After the laser emits pulsed light, it enters the grating array of the OPGW line through the first circulator, and then continues to enter the unbalanced interferometer through the second circulator to realize the measurement of the monitoring signal.
5. The OPGW tower periodic galloping monitoring method according to claim 4, wherein The laser includes: a narrow linewidth laser.
6. An OPGW tower periodic galloping monitoring device, characterized in that, Including: An acquisition module for obtaining the monitoring signal of the periodic galloping of the OPGW tower; A phase module for calculating the phase signal of a single said monitoring signal based on the vibration phase demodulation method; A matrix module for composing the phase signals into a signal matrix according to the spatial and numbering order of the monitoring signals; A transformation module for performing a Hilbert transform on the signal matrix to convert the real signal into a complex signal; A decomposition module for decomposing the complex signal into modal functions; A filtering module for identifying and filtering out the part of the modal function containing high-frequency noise; A combination module for recombining the modal functions after noise filtering to obtain the denoised monitoring signal of the periodic galloping of the OPGW tower.
7. The OPGW tower periodic galloping monitoring device according to claim 6, wherein, The phase module calculates the phase signal of a single said monitoring signal based on the vibration phase demodulation method, including: The phase signal obtained by the i-th sensor at the j-th sampling point is: Among them, is the phase change amount caused by the galloping of the optical cable, is the initial phase, f0 is the galloping period, and S is the sampling rate.
8. The OPGW tower periodic galloping monitoring device according to claim 6, characterized in that, The transformation module performs a Hilbert transform on the signal matrix, and the expression is as follows: where, m i (t) is the modal component inherent in the array, r n (t) is the residual component.
9. The OPGW tower periodic galloping monitoring device according to claim 6, wherein The acquisition module obtains the monitoring signal of the periodic galloping of the OPGW tower, including: After the laser emits pulsed light, it enters the grating array of the OPGW line through the first circulator, and then continues to enter the unbalanced interferometer through the second circulator to realize the measurement of the monitoring signal.
10. The OPGW tower periodic galloping monitoring device according to claim 9, characterized in that, The laser includes: a narrow linewidth laser.