A fast and accurate positioning method for OPGW towers based on multi-dimensional parameter fusion

Abstract

The present invention discloses a method for rapid and precise positioning of OPGW towers based on multidimensional parameter fusion. The method comprises: obtaining preliminary positioning values ​​for the tension tower using amplitude parameters as a carrier, preliminary positioning values ​​for the connection tower using frequency shift parameters as a carrier, preliminary positioning values ​​for the tension tower using strain parameters as a carrier, and preliminary positioning values ​​for the linear tower using temperature parameters as a carrier based on collected backscattered Rayleigh and Brillouin scattering signals. These four parameters are then compared with a tower geographic spacing map to complete the tower positioning information. Based on the tower point positioning information and the actual geographic distance, a mapping relationship is constructed between the fiber optic cable length of the entire line and the line geographic information. The geographic location of the abnormal event is calculated using this mapping relationship. The present invention overcomes the limitations of positioning based on a single physical parameter and achieves rapid and precise positioning of OPGW line towers.

Description

Technical Field

[0001] The present invention belongs to the technical field of OPGW tower positioning and monitoring, and in particular relates to a method for quickly and accurately positioning an OPGW tower based on multi-dimensional parameter fusion. Background Art

[0002] Transmission lines are subject to natural or human influences, and may experience abnormal phenomena such as icing, dancing, and lightning strikes, resulting in significant economic losses and negative social impacts. Their safe and stable operation is crucial to maintaining national economic development and social stability. Distributed Optical Fiber Sensor (DOFS) technology uses optical fiber as both a sensing and information transmission medium, enabling monitoring of various physical parameters along the fiber line, including temperature, vibration, and strain. Optical Fiber Composite Overhead Ground Wire (OPGW) is widely used in high-voltage overhead transmission lines due to its high reliability, long lifespan, and cost-effectiveness. It combines the electrical and mechanical performance of overhead ground wires with the communication capabilities of optical cables. Combining DOFS technology with high-voltage overhead transmission lines effectively utilizes idle OPGW resources. Without requiring on-site line modification, equipment installation, or communication networking, DOFS technology can extend sensing capabilities to power transmission lines with minimal investment, enabling long-term, continuous, and online monitoring of transmission lines.

[0003] OPGWs are installed on towers. Their temperature, strain, and vibration characteristics are affected by the structure, resulting in significant differences from the overhead lines between adjacent towers. DOFS technology can leverage these anomalies to map the length of the sensing fiber's sheath to the geographic location of each tower along the transmission line. Furthermore, using the towers as anchor points, the entire line can be calibrated through methods such as interpolation. Currently, many research groups have experimented with using DOFS technology to directly locate towers along OPGW lines.

[0004] The invention with publication number CN116484196A discloses a method and system for identifying vibration areas of OPGW optical cables based on wavenumber domain analysis. This invention can identify areas prone to vibration hazards where the internal fiber core strain is abnormal due to long-term vibration of the optical cable. The invention with publication number CN114039656B discloses a method and device for locating OPGW faults based on BOTDR and OTDR. This method can determine the tower where the fault is located by combining the positions of the connected tower and the non-connected tower and their corresponding cumulative optical fiber lengths, and accurately locate the connection point. The invention with publication number CN110927524B discloses a method for analyzing and accurately locating the cause of OPGW optical cable core breakage based on BOTDR technology, which can determine whether the core breakage position is at the Brillouin frequency shift jump.

[0005] However, existing tower positioning methods mostly focus on identifying connected towers by analyzing the BFS jump phenomenon caused by fiber splicing at the connecting tower and the monitoring signal anomalies caused by the special cable fixing structure at the tower. On the one hand, the number of connecting towers in a transmission line is far less than the total number of line towers. On the other hand, existing methods have a single monitoring parameter and judgment method. The positioning results are significantly affected by the meteorological conditions around the transmission line, and they also lack positioning accuracy and speed.

[0006] Therefore, it is necessary to solve the problems of OPGW tower positioning accuracy and positioning speed, and it is necessary to develop a comprehensive, accurate and fast OPGW tower positioning method. Summary of the Invention

[0007] Technical Problem Solved: This invention discloses a method for rapid and precise positioning of OPGW towers based on multidimensional parameter fusion. This method simultaneously monitors multiple parameters, including vibration, temperature, and strain, of high-voltage overhead transmission lines. Based on a comprehensive analysis of the characteristics and mechanisms of each parameter, this method overcomes the limitations of positioning based on a single physical parameter, enabling rapid and precise positioning of OPGW line towers. This invention not only provides a viable approach for building a ubiquitous power Internet of Things based on distributed fiber optic sensing technology, but also has significant potential for improving power grid operations and maintenance.

[0008] Technical solution:

[0009] A method for quickly and accurately positioning an OPGW tower based on multi-dimensional parameter fusion, the method comprising the following steps:

[0010] S1, using a distributed fiber optic sensing system to monitor the entire OPGW tower line, collecting the Rayleigh backscattered signal containing vibration information in the OPGW tower optical fiber and the Brillouin scattering signal containing strain, temperature, and Brillouin frequency shift data of the entire OPGW tower line;

[0011] S2, based on the collected backscattered Rayleigh signal, obtains the preliminary positioning value of the tension tower with the amplitude parameter as the carrier;

[0012] S3, based on the collected Brillouin scattering signal, obtain the preliminary positioning value of the tension tower based on the strain parameter, the preliminary positioning value of the straight tower based on the temperature parameter, and the preliminary positioning value of the connection tower based on the frequency shift parameter;

[0013] S4, using the preliminary positioning value of the tension tower based on the amplitude parameter, the preliminary positioning value of the connection tower based on the frequency shift parameter, the preliminary positioning value of the tension tower based on the strain parameter, and the preliminary positioning value of the linear tower based on the temperature parameter as four parameters, and comparing the four parameters with the geographical spacing map of the towers to determine whether the towers are positioned; wherein, for the tower points that are positioned, the accuracy of the four-parameter positioning is measured, and the most accurate positioning result is taken as the actual position of the tower point; for the tower points that are not positioned, a linear interpolation positioning algorithm is used to calculate the missing towers to complete the tower positioning information;

[0014] S5: Based on the tower location information and the actual geographical distance, a mapping relationship between the fiber optic skin length of the entire line and the line geographical information is constructed, and the geographical location of the abnormal event is calculated using the mapping relationship between the fiber optic skin length of the entire line and the line geographical information.

[0015] Step S2 further comprises:

[0016] S21, using a window function to divide the vibration signal into overlapping window segments, calculating the sum of squares within each window as the short-time energy of the window; calculating the short-time energy of each sampling point of the vibration signal in units of 2 minutes, and then calculating the average short-time energy within 2 minutes of the same sampling point, and combining them in order to obtain a spatiotemporal distribution diagram of the short-time energy of the vibration signal;

[0017] S22, designing a first sliding variance window based on the transmission voltage level of the line, the height of the tower, the excess length of the optical cable at the connecting tower, the overall length of the line, the number of tension towers, and the spatial resolution of the distributed optical fiber sensing system, so that each first sliding variance window contains only one tension tower; using the first sliding variance window to segment the spatiotemporal distribution map of the short-time energy of the vibration signal, and calculating the signal variance of each first sliding variance window;

[0018] S23, setting a threshold based on factors such as the difference in vibration amplitude between the suspended optical cable and the fixed optical cable at the tension tower, the length of the down conductor and the residual cable on the tension tower, and the like. One-sixth of the mean of the variance of the first sliding window is used as the judgment threshold. Areas where the variance is below the judgment threshold are marked as potential abnormal areas, indicating that these areas may contain tension towers.

[0019] S24, performing a deduplication operation on the screened potential abnormal area: for adjacent decision points in the area, selecting the data point with the lowest vibration energy as the most accurate position of the tension tower, and serving as the preliminary positioning value of the tension tower.

[0020] Step S3 further comprises:

[0021] S31, using a distributed optical fiber sensing system to monitor the strain, temperature, and Brillouin frequency shift data of the entire OPGW tower line, and obtain the original Brillouin scattering signal distribution in the optical fiber of the entire OPGW tower line;

[0022] S32, treating the last 1000 data points of the original Brillouin scattering signal as noise, calculating the noise mean and subtracting this portion of the value to remove the baseline noise; then replacing the value of each data point with the mean of its surrounding data points, smoothing the Brillouin scattering signal, and obtaining a denoised Brillouin scattering signal distribution;

[0023] S33, using the BFS signal processing algorithm to process and denoise the Brillouin scattering signal distribution and obtain the Brillouin frequency shift curve;

[0024] S34, using an outlier screening algorithm to process the Brillouin frequency shift curve to obtain Brillouin frequency shift outlier points;

[0025] S35, the Brillouin frequency shift anomaly point is determined by using the Brillouin frequency shift anomaly point determination method to obtain the preliminary positioning value of the tension tower with the strain parameter as the carrier, the preliminary positioning value of the straight tower with the temperature parameter as the carrier, and the preliminary positioning value of the connection tower with the frequency shift parameter as the carrier.

[0026] Step S33 further includes:

[0027] S331, determine the Brillouin scattering peak position, select data points within a specified range near the peak for local analysis; around the selected data points, use a quadratic polynomial based on the least squares method to perform curve fitting to obtain a quadratic function that approximates the Brillouin scattering peak shape:

[0028] p(F)=aF 2 +bF+c

[0029] Where F is the frequency, and a, b, and c are the polynomial coefficients. The optimal fitting parameters are found by iteratively searching for the minimum residual sum of squares between the original data and the binomial function. The RSS calculation formula is:

[0030]

[0031] Among them, S i is the original data; when the peak position converges or reaches the preset upper limit of fitting times, the quadratic polynomial fitting is stopped to obtain the fitting peak point;

[0032] S332, determining the precise value of the Brillouin peak frequency shift of the entire line based on the fitted peak point, and generating a Brillouin frequency shift curve for the entire line.

[0033] Step S34 further includes:

[0034] S341, designing a second sliding variance window based on the transmission voltage level of the line, the height of the tower, and the excess length of the optical cable at the connecting tower. The designed second sliding variance window is greater than the total length of the down conductor and the excess cable at a single connecting tower and less than the span of any section of the measurement line, so that each second sliding variance window contains only one connecting tower; using the second sliding variance window to segment the Brillouin frequency shift curve, and calculating the signal variance of each second sliding variance window;

[0035] S342, using the mean of the variance of the second sliding window as a determination threshold, marking areas where the variance is lower than the determination threshold as potential abnormal areas, and considering that these areas may contain connection towers;

[0036] S343: In each identified potential abnormal area, the center point of the sliding window corresponding to the maximum variance is considered to be the most accurate position of the BFS jump point; the variance result is analyzed using the peak finding algorithm, and the quadratic function fitting algorithm is used to fit the result to find the local variance peak point as the BFS abnormal point.

[0037] Step S35 further includes:

[0038] S351, set a sliding window, with the Brillouin frequency shift anomaly point as the center and the BFS data of ±30m on the left and right as the window size, and split the array;

[0039] S352, traverse the array, find all monotonic intervals, sort them by length, and extract the two longest monotonic intervals for use;

[0040] S353 calculates the slopes of the two monotonic intervals and determines the slope threshold to distinguish normal fluctuations of the BFS signal from abnormal changes caused by peaks and jumps. Arrays with slopes below the slope threshold are cleared. The slope threshold is related to the spatial resolution of the monitoring equipment and the length of the affected optical cable segment caused by the structure of the monitored high-voltage overhead transmission line tower.

[0041] S354, after completing the slope threshold determination, screen the remaining non-empty arrays; if there is no non-empty array, it proves that there is no reasonable peak or jump here, and this place is determined to be a noise point; if there is only one non-empty array here, it is determined to be a BFS jump point, corresponding to the preliminary positioning value of the connection tower with the frequency shift parameter as the carrier; if there are two non-empty monotonic arrays here, compare the slopes and orders of the two arrays. If the slopes of the two monotonic arrays are opposite, and the index of the array with a positive slope in the original array is greater than the array with a negative slope, it is considered that there is a peak here, corresponding to the preliminary positioning value of the tension tower with the strain parameter as the carrier and the preliminary positioning value of the straight tower with the temperature parameter as the carrier, otherwise this place is determined to be a noise point.

[0042] Step S4 further comprises:

[0043] S41, comparing the four parameters with the tower geographical spacing map to determine whether the tower is positioned; for tower points that are positioned, measuring the accuracy of the four-parameter positioning, and taking the most accurate one as the actual position of the tower point; for tower points that are not positioned, using a linear interpolation positioning algorithm to calculate the geographical location of the missing tower to complete the tower positioning information;

[0044] S42, constructing a mapping relationship between the fiber optic skin length of the entire line and the actual geographical information of the line based on the positioning result of the tower point and the actual geographical distance;

[0045] S43: When the distributed fiber optic sensing system detects an abnormal event, it locates the event within the span between two towers based on the mapping relationship between the fiber optic sheath length of the entire line and the actual geographic information of the line. Then, within the located span, the function interpolation positioning algorithm is used to calculate the geographic location of the event.

[0046] Furthermore, in step S41, the process of calculating the geographical location of the missing tower using the linear interpolation positioning algorithm includes the following steps:

[0047] If the actual geographical location of the route is known, L n Corresponding to tower N position Y n , geographical location L n+2 Corresponding to tower N+2 position Y n+2 If tower N+1 fails to locate effective features in the distributed optical fiber system, the known data points (L n ,Y n ) and (L n+2 ,Y n+2 ), for unknown data point Y n+1 Perform interpolation estimation:

[0048]

[0049] Furthermore, in step S43, the process of calculating the geographical location of the event using the function interpolation positioning algorithm includes the following steps:

[0050] S431, establish the spatial coordinates of the overhead line, where the x-axis is the horizontal length of the overhead line, and the y-axis is the vertical height of the overhead line; the lowest point of the overhead line is point O; point A is the coordinate of the tower on the left side of the overhead line; point B is the coordinate of the tower on the right side of the overhead line; points C and D represent the coordinates of two points on the overhead line;

[0051] S432, based on the catenary method, the state equation for the overhead line length is:

[0052]

[0053] Among them, S is the length of the overhead line in section CD, T0 is the tension at the left end point C, is the angle between the tangent line of the left endpoint C and the horizontal, and q is the weight of the overhead line itself;

[0054] S433, the total length of the overhead line AB section is the sum of the length of the AO section and the length of the OB section, a is the horizontal distance of the AO section, b is the horizontal distance of the OB section, and integrating the state equation yields:

[0055]

[0056] S434, let the event occur at a distance S0 from the tower, and compare S0 with the calculated L AB , L AO Compare and confirm the segment where the event is located, and calculate the actual geographic location x of the event as:

[0057]

[0058] Beneficial effects:

[0059] First, the OPGW tower fast and accurate positioning method based on multi-dimensional parameter fusion of the present invention combines OPGW and DOFS technology to achieve accurate mapping between optical fiber skin length and actual tower coordinates of the line.

[0060] Second, the present invention's method for rapid and precise positioning of OPGW towers based on multi-dimensional parameter fusion utilizes a fused distributed optical fiber sensing system to comprehensively consider multiple physical parameters such as vibration, temperature, and strain, thereby achieving effective positioning of two different types of towers: tension towers and straight towers in transmission lines.

[0061] Third, the OPGW tower rapid and precise positioning method based on multi-dimensional parameter fusion of the present invention significantly improves the number, speed and accuracy of transmission line tower positioning, and has significant practical application value for improving the operation and maintenance level of the power system.

[0062] Fourth, the OPGW tower fast and accurate positioning method based on multi-dimensional parameter fusion of the present invention calculates the precise positioning value of abnormal events through interpolation algorithm, and realizes early warning of abnormal phenomena such as icing, dancing, and lightning strikes of high-voltage overhead transmission lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 This is a flow chart of a method for rapid and accurate positioning of an OPGW tower based on multi-dimensional parameter fusion according to an embodiment of the present invention;

[0064] Figure 2 Schematic diagram of the flow of the BFS signal processing algorithm according to an embodiment of the present invention.

[0065] Figure 3Schematic diagram of the process of the four-parameter fusion tower positioning method according to an embodiment of the present invention.

[0066] Figure 4 Schematic diagram of the overhead line force according to an embodiment of the present invention. DETAILED DESCRIPTION

[0067] The following examples may enable those skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.

[0068] Example 1

[0069] The embodiment of the present invention discloses a method for quickly and accurately positioning an OPGW tower based on multi-dimensional parameter fusion, the method comprising the following steps:

[0070] S1, using a distributed fiber optic sensing system to monitor the entire OPGW tower line, collecting the Rayleigh backscattered signal containing vibration information in the OPGW tower optical fiber and the Brillouin scattering signal containing strain, temperature, and Brillouin frequency shift data of the entire OPGW tower line;

[0071] S2, based on the collected backscattered Rayleigh signal, obtains the preliminary positioning value of the tension tower with the amplitude parameter as the carrier;

[0072] S3, based on the collected Brillouin scattering signal, obtain the preliminary positioning value of the tension tower based on the strain parameter, the preliminary positioning value of the straight tower based on the temperature parameter, and the preliminary positioning value of the connection tower based on the frequency shift parameter;

[0073] S4, using the preliminary positioning value of the tension tower based on the amplitude parameter, the preliminary positioning value of the connection tower based on the frequency shift parameter, the preliminary positioning value of the tension tower based on the strain parameter, and the preliminary positioning value of the linear tower based on the temperature parameter as four parameters, and comparing the four parameters with the geographical spacing map of the towers to determine whether the towers are positioned; wherein, for the tower points that are positioned, the accuracy of the four-parameter positioning is measured, and the most accurate positioning result is taken as the actual position of the tower point; for the tower points that are not positioned, a linear interpolation positioning algorithm is used to calculate the missing towers to complete the tower positioning information;

[0074] S5: Based on the tower location information and the actual geographical distance, a mapping relationship between the fiber optic skin length of the entire line and the line geographical information is constructed, and the geographical location of the abnormal event is calculated using the mapping relationship between the fiber optic skin length of the entire line and the line geographical information.

[0075] As a preferred example, the process of obtaining a preliminary positioning value of a tension tower based on the collected backscattered Rayleigh signal with the amplitude parameter as the carrier includes the following steps:

[0076] Step A1: using a fusion distributed optical fiber sensing system to monitor the amplitude data of the entire OPGW tower line and collect the Rayleigh backscattered signal containing vibration information in the optical fiber of the OPGW tower;

[0077] Step A2: performing signal preprocessing on the collected backscattered Rayleigh signal, including suppressing its broadband noise through intermediate frequency filtering and removing unnecessary high-frequency and low-frequency components in the signal to obtain an intermediate frequency signal; downsampling the intermediate frequency signal and extracting data proportionally to reduce the data volume and improve the efficiency of subsequent processing; constructing a local oscillator and performing IQ demodulation on the sampled intermediate frequency signal to obtain a vibration signal;

[0078] In step A3, the vibration signal is processed using an amplitude minimum signal processing algorithm to obtain a preliminary tower positioning value based on the amplitude parameter. To reduce errors in the determination process, line sections with low overall amplitude, where tower identification is more difficult, are excluded.

[0079] In this embodiment, the backscattered Rayleigh signal is collected by an acquisition card, filtered through an intermediate frequency filter, and downsampled to obtain a vibration signal. After obtaining the vibration signal, this embodiment also requires calculating the preliminary positioning value of the tension tower using an amplitude minimum signal processing algorithm.

[0080] Specifically, the vibration signal is divided into overlapping window segments using the Blackman window function, and the sum of squares in each window is calculated as the short-time energy of the window; the short-time energy of each sampling point of the vibration signal is calculated in units of 2 minutes, and then the average short-time energy within 2 minutes of the same sampling point is calculated, and the short-time energy spatiotemporal distribution diagram of the vibration signal is obtained by combining them in sequence.

[0081] A sliding variance window size of 1 km is designed based on the transmission voltage level of the line, the height of the tower, the excess length of the optical cable at the connecting tower, the overall length of the line, the number of tension towers, and the spatial resolution of the distributed optical fiber sensing system, so that only one tension tower is included in a sliding window. The sliding variance window segments the short-time energy spatiotemporal distribution map of the vibration signal, and the signal variance of each window is calculated.

[0082] Thresholds were set based on factors such as the difference in vibration amplitude between the suspended optical cable and the fixed optical cable at the tension tower, as well as the length of the down conductor and residual cable on the tension tower. One-sixth of the mean variance of the sliding window was used as the judgment threshold. Regions with variances below the specified threshold were marked as potential anomalies, indicating the presence of a tension tower. Duplicate removal was performed on these identified potential anomaly regions. Specifically, for adjacent decision points within the region, the data point with the lowest vibration energy was selected as the most accurate position of the tension tower, serving as the initial positioning value for the tower.

[0083] It should be noted that the sliding window size and threshold values ​​of this embodiment are not limited to the aforementioned examples. They can be set as needed based on actual conditions, such as the overall line length, the number of tension towers, the spatial resolution of the distributed optical fiber sensing system, the difference in vibration amplitude between the suspended optical cable and the fixed optical cable at the tension tower, and the length of the down conductor and residual cable on the tension tower. The parameters in the following embodiments are also not limited and are provided for illustrative purposes only, so they will not be repeated here.

[0084] As a preferred example, based on the collected Brillouin scattering signal, obtaining the preliminary positioning value of the tension tower with the strain parameter as the carrier, the preliminary positioning value of the straight tower with the temperature parameter as the carrier, and the preliminary positioning value of the connection tower with the frequency shift parameter as the carrier includes the following steps:

[0085] Step B1: using a fusion distributed optical fiber sensing system to monitor the strain, temperature, and Brillouin frequency shift data of the entire OPGW tower line, and obtaining the original Brillouin scattering signal distribution in the optical fiber of the entire OPGW tower line;

[0086] Step B2: Treat the last 1000 data points of the signal as noise, calculate the noise mean, and subtract this part of the value to remove the baseline noise; then replace the value of each data point with the mean of its surrounding data points, smooth the signal, and obtain the denoised Brillouin scattering signal distribution;

[0087] Step B3, using a BFS signal processing algorithm to process the denoised Brillouin scattering signal distribution to obtain a Brillouin frequency shift curve;

[0088] Step B4: Process the Brillouin frequency shift curve using an outlier screening algorithm to obtain Brillouin frequency shift outlier points.

[0089] In step B5, the Brillouin frequency shift abnormal point is determined by the Brillouin frequency shift abnormal point determination method to obtain the preliminary positioning value of the tension tower with the strain parameter as the carrier, the preliminary positioning value of the straight tower with the temperature parameter as the carrier, and the preliminary positioning value of the connection tower with the frequency shift parameter as the carrier.

[0090] In this embodiment, the BFS signal processing algorithm is used to process the denoised Brillouin scattering signal distribution to obtain a Brillouin frequency shift curve. The Brillouin frequency shift curve is then processed using an outlier screening algorithm to identify Brillouin frequency shift outliers. These Brillouin frequency shift outliers are then identified using the Brillouin frequency shift outlier determination method to obtain preliminary positioning values ​​for tension towers using strain parameters as a carrier, for linear towers using temperature parameters as a carrier, and for splicing towers using frequency shift parameters as a carrier.

[0091] Specifically, we first determine the approximate location of the Brillouin scattering peak and select data points within a certain range near the peak for local analysis. Curve fitting is performed around the selected data points. A quadratic polynomial fit based on the least squares method is used to approximate the shape of the Brillouin scattering peak. The goal of the fit is to find a quadratic function:

[0092] p(F)=aF 2 +bF+c

[0093] The best approximation of the original peak value is achieved. Where F is the frequency, and a, b, and c are the polynomial coefficients. The best fitting parameters are found by iteratively searching for the minimum residual sum of squares (RSS) between the original data and the binomial function. The RSS calculation formula is:

[0094]

[0095] Among them, S i The binomial fit is terminated when the peak position converges or reaches the preset upper limit of the fitting times. The fitted peak point is then used to determine the precise value of the full-line Brillouin peak frequency shift and generate the full-line Brillouin frequency shift curve.

[0096] like Figure 2 As shown in the figure, the Brillouin frequency shift curve is processed using the outlier screening algorithm to obtain the Brillouin frequency shift outlier points. Based on the transmission voltage level of the line, the height of the tower and the excess length of the optical cable at the connecting tower, the sliding variance window size is designed to be 60m. The sliding window size should be slightly larger than the total length of the down conductor and the excess cable at a single connecting tower, and smaller than the span of any section of the measurement line to ensure that each sliding window contains only one connecting tower. The sliding variance window is used to segment the Brillouin frequency shift curve, and the signal variance of each window is calculated;

[0097] The sliding window variance mean is used as the judgment threshold; areas with variance below a specific threshold are marked as potential abnormal areas, and it is believed that these areas may have connection towers.

[0098] Within each identified potential anomaly region, we further search for local peaks. The center of the sliding window corresponding to the maximum variance within this segment is considered the most accurate location of the BFS transition point. We analyze the variance results using a peak-finding algorithm and perform a quadratic function fitting algorithm to find the local variance peaks as BFS anomaly points.

[0099] Set a sliding window with the Brillouin frequency shift anomaly point as the center and the BFS data within ±30m on both sides as the window size to split the array; traverse the array to find all monotonic intervals, sort them by length, and extract the two longest monotonic intervals for use;

[0100] The slopes of these two intervals are calculated and a slope threshold is determined to distinguish normal BFS signal fluctuations from abnormal changes caused by peaks and jumps. Arrays below the threshold are cleared. The threshold is determined based on factors such as the spatial resolution of the monitoring equipment and the length of the affected optical cable segment due to the structure of the monitored high-voltage overhead transmission line towers. A slope threshold of 30 MHz / m is selected.

[0101] After completing the slope threshold determination, the remaining non-empty arrays are screened. If no non-empty array exists, it indicates that there is no reasonable peak or jump at this location, and the location is determined to be a noise point. If only one non-empty array exists at this location, it is determined to be a BFS jump point, corresponding to the preliminary positioning value of the connecting tower based on the frequency shift parameter. If two non-empty monotonic arrays exist at this location, the slopes and order of the two arrays are compared. If the slopes of the two monotonic arrays are opposite, and the index of the array with the positive slope in the original array is greater than that of the array with the negative slope, then a peak is considered to exist at this location, corresponding to the preliminary positioning value of the tension tower based on the strain parameter or the preliminary positioning value of the linear tower based on the temperature parameter. Otherwise, the location is determined to be a noise point.

[0102] Based on the aforementioned preliminary tower positioning values, this embodiment proposes a four-parameter fusion tower positioning method, such as Figure 3 As shown. The preliminary positioning value of the tension tower using the amplitude parameter as the carrier obtained in steps A1-A3, the preliminary positioning value of the connection tower using the frequency shift parameter as the carrier, the preliminary positioning value of the tension tower using the strain parameter as the carrier, and the preliminary positioning value of the linear tower using the temperature parameter as the carrier obtained in steps B1-B5 are used as four parameters, and the precise positioning value of the tower and the precise positioning value of the abnormal event are calculated using the fusion tower positioning method, which includes the following steps:

[0103] In step C1, the four parameters are compared with the tower geographic spacing map to determine whether the tower has been located. For tower points that have been located, the accuracy of the four features is measured, and the most accurate one is taken as the actual location of the point. For tower points that have not been located, a linear interpolation positioning algorithm is used to calculate the missing towers and complete the tower location information.

[0104] Step C2: Based on the positioning results of the towers and the actual geographical distance, an accurate mapping relationship between the fiber optic cable length and the line geographical information is constructed.

[0105] In step C3, after establishing a mapping relationship between the fiber optic cable length and the actual geographic location, when the distributed fiber optic sensing system detects an abnormal event, it first roughly locates the event to the span between two towers based on this mapping relationship. Then, within this span, a function interpolation positioning algorithm is used to calculate the event's exact geographic location.

[0106] Specifically, for the tower points that have not been located, a linear interpolation positioning algorithm is used to calculate the missing towers. Assuming that the actual geographical spans of the line are L1, L2...L n 、L n+1 、L n+2 ......, the optical fiber skin length located by the distributed optical fiber sensing system corresponds to the tower position Y1, Y2......Y n 、Y n+1 、Y n+2 ....... If the geographical location L is known n Corresponding to tower N position Y n , geographical location L n+2 Corresponding to tower N+2 position Y n+2 , tower N+1 fails to locate effective features in the distributed optical fiber system. Using the known data points (L n ,Y n ) and (L n+2 ,Y n+2 ), for unknown data point Y n+1 Perform interpolation estimation.

[0107] Calculate the slope k as:

[0108]

[0109] Then Y n+1 The values ​​are:

[0110] Y n+1 =Y n +k(L n+1 -L n );

[0111] We can get:

[0112]

[0113] Figure 4 This is a schematic diagram of the stresses on overhead lines. For abnormal phenomena such as icing, dancing, and lightning strikes, a function interpolation positioning algorithm is used to calculate the precise geographic location of the event. The spatial coordinates of the overhead line are established, with the x-axis representing the horizontal length of the overhead line and the y-axis representing the vertical height. Point O is the lowest point of the overhead line. Point A represents the coordinates of the tower on the left side of the overhead line. Point B represents the coordinates of the tower on the right side of the overhead line. Points C and D represent the coordinates of two points on the overhead line.

[0114] The state equation of the overhead line length established according to the catenary method is:

[0115]

[0116] Among them, S is the length of the overhead line in section CD, T0 is the tension at the left end point C, is the angle between the tangent line of the left endpoint C and the horizontal, and q is the weight of the overhead line itself;

[0117] The total length of the overhead line AB section is the sum of the length of the AO section and the length of the OB section. a is the horizontal distance of the AO section, and b is the horizontal distance of the OB section. Integrating the state equation yields:

[0118]

[0119] In the formula, the event occurs at a distance S0 from the tower. Compare S0 with the calculated LAB and LAO to confirm its section and calculate its actual geographical location x:

[0120]

[0121] This embodiment discloses a method for rapid and accurate positioning of OPGW towers based on multi-dimensional parameter fusion. It integrates the aforementioned monitoring and positioning methods, utilizes distributed fiber optic sensing technology, and synchronously acquires multiple physical parameters such as temperature, strain, and vibration along the optical cable. Different targeted analysis and processing methods are adopted for different parameters, and the most accurate one is taken as the actual position of the tower. The missing towers are supplemented, and an accurate mapping relationship between the fiber optic skin length of the entire line and the line geographic information is established, and abnormal events are accurately positioned.

[0122] Example 2

[0123] like Figure 1 As shown, this embodiment also discloses an OPGW tower rapid and precise positioning system based on multi-dimensional parameter fusion, and the OPGW tower rapid and precise positioning system includes a data acquisition module 1, a data processing module 2, and a tower and abnormal event positioning module 3.

[0124] Data acquisition module 1 is used to collect the backscattered Rayleigh and Brillouin scattering signal distributions on the optical fiber of the OPGW tower, respectively collecting amplitude, strain, temperature, and Brillouin frequency shift characteristics. Data processing module 2 is used to process the backscattered Rayleigh and Brillouin scattering signal distributions to obtain preliminary tower positioning values. The backscattered Rayleigh signal processing is used to preliminarily locate the tension tower, and the Brillouin scattering signal distribution is used to preliminarily locate the tension tower and linear tower. Tower and abnormal event positioning module 3 includes precise positioning and completion of tower positions, as well as precise positioning of abnormal events. All of the above utilize the method of Example 1, calculating the precise positioning values ​​of the tower and the precise positioning values ​​of abnormal events based on the four-parameter fusion tower positioning method.

[0125] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for rapid and accurate positioning of OPGW towers based on multi-dimensional parameter fusion, characterized in that: The OPGW tower rapid and accurate positioning method comprises the following steps: S1, using a distributed fiber optic sensing system to monitor the entire OPGW tower line, collecting the Rayleigh backscattered signal containing vibration information in the OPGW tower optical fiber and the Brillouin scattering signal containing strain, temperature, and Brillouin frequency shift data of the entire OPGW tower line; S2, based on the collected backscattered Rayleigh signal, obtains the preliminary positioning value of the tension tower with the amplitude parameter as the carrier; S3, based on the collected Brillouin scattering signal, obtain the preliminary positioning value of the tension tower based on the strain parameter, the preliminary positioning value of the straight tower based on the temperature parameter, and the preliminary positioning value of the connection tower based on the frequency shift parameter; S4, using the preliminary positioning value of the tension tower based on the amplitude parameter, the preliminary positioning value of the connection tower based on the frequency shift parameter, the preliminary positioning value of the tension tower based on the strain parameter, and the preliminary positioning value of the straight tower based on the temperature parameter as four parameters, and comparing the four parameters with the geographical spacing map of the towers to determine whether the towers are positioned; wherein, for the tower points that are positioned, the accuracy of the four-parameter positioning is measured, and the most accurate positioning result is taken as the actual position of the tower point; for the tower points that are not positioned, a linear interpolation positioning algorithm is used to calculate the missing towers to complete the tower positioning information; the process of calculating the geographical location of the missing towers using the linear interpolation positioning algorithm includes the following steps: If the actual geographical location of the route is known, L n Corresponding to tower N position Y n , geographical location L n+2 Corresponding to tower N+2 position Y n+2 If tower N+1 fails to locate effective features in the distributed optical fiber system, the known data points (L n ,Y n ) and (L n+2 ,Y n+2 ), for unknown data point Y n+1 Perform interpolation estimation: S5, based on the tower point positioning information and the actual geographical distance, construct a mapping relationship between the optical fiber skin length of the entire line and the line geographical information, and use the mapping relationship between the optical fiber skin length of the entire line and the line geographical information to calculate the geographical location of the abnormal event; specifically, when the distributed optical fiber sensing system monitors an abnormal event, based on the mapping relationship between the optical fiber skin length of the entire line and the actual geographical information of the line, the event is located within the span interval between the two towers; then, within the located span interval, a function interpolation positioning algorithm is used to calculate the geographical location of the event; wherein, the process of using the function interpolation positioning algorithm to calculate the geographical location of the event includes the following steps: S51, establishing the spatial coordinates of the overhead line, where the x-axis represents the horizontal length of the overhead line and the y-axis represents the vertical height of the overhead line; the lowest point of the overhead line is point O; point A represents the coordinates of the tower on the left side of the overhead line; point B represents the coordinates of the tower on the right side of the overhead line; points C and D represent the coordinates of two points on the overhead line; S52, based on the catenary method, the state equation of the overhead line length is established as: Among them, S is the length of the overhead line in section CD, T0 is the tension at the left end point C, is the angle between the tangent line of the left endpoint C and the horizontal, and q is the weight of the overhead line itself; S53, the total length of the overhead line AB section is the sum of the length of the AO section and the length of the OB section, a is the horizontal distance of the AO section, b is the horizontal distance of the OB section, and integrating the state equation yields: S54, let the event occur at a distance S0 from the tower, and compare S0 with the calculated L AB , L AO Compare and confirm the segment where the event is located, and calculate the actual geographic location x of the event as:

2. The method for rapid and accurate positioning of OPGW towers based on multi-dimensional parameter fusion according to claim 1, characterized in that: Step S2 further comprises: S21, using a window function to divide the vibration signal into overlapping window segments, calculating the sum of squares within each window as the short-time energy of the window; calculating the short-time energy of each sampling point of the vibration signal in units of 2 minutes, and then calculating the average short-time energy within 2 minutes of the same sampling point, and combining them in order to obtain a spatiotemporal distribution diagram of the short-time energy of the vibration signal; S22, designing a first sliding variance window based on the transmission voltage level of the line, the height of the tower, the excess length of the optical cable at the connecting tower, the overall length of the line, the number of tension towers, and the spatial resolution of the distributed optical fiber sensing system, so that each first sliding variance window contains only one tension tower; using the first sliding variance window to segment the spatiotemporal distribution map of the short-time energy of the vibration signal, and calculating the signal variance of each first sliding variance window; S23, setting a threshold based on factors such as the difference in vibration amplitude between the suspended optical cable and the fixed optical cable at the tension tower, the length of the down conductor and the residual cable on the tension tower, and the like. One-sixth of the mean of the variance of the first sliding window is used as the judgment threshold. Areas where the variance is below the judgment threshold are marked as potential abnormal areas, indicating that these areas may contain tension towers. S24, performing a deduplication operation on the screened potential abnormal area: for adjacent decision points in the area, selecting the data point with the lowest vibration energy as the most accurate position of the tension tower, and serving as the preliminary positioning value of the tension tower.

3. The method for rapid and accurate positioning of OPGW towers based on multi-dimensional parameter fusion according to claim 1, characterized in that: Step S3 further comprises: S31, using a distributed optical fiber sensing system to monitor the strain, temperature, and Brillouin frequency shift data of the entire OPGW tower line, and obtain the original Brillouin scattering signal distribution in the optical fiber of the entire OPGW tower line; S32, treating the last 1000 data points of the original Brillouin scattering signal as noise, calculating the noise mean and subtracting this portion of the value to remove the baseline noise; then replacing the value of each data point with the mean of its surrounding data points, smoothing the Brillouin scattering signal, and obtaining a denoised Brillouin scattering signal distribution; S33, using the BFS signal processing algorithm to process and denoise the Brillouin scattering signal distribution and obtain the Brillouin frequency shift curve; S34, using an outlier screening algorithm to process the Brillouin frequency shift curve to obtain Brillouin frequency shift outlier points; S35, the Brillouin frequency shift anomaly point is determined by using the Brillouin frequency shift anomaly point determination method to obtain the preliminary positioning value of the tension tower with the strain parameter as the carrier, the preliminary positioning value of the straight tower with the temperature parameter as the carrier, and the preliminary positioning value of the connection tower with the frequency shift parameter as the carrier.

4. The method for rapid and accurate positioning of OPGW towers based on multi-dimensional parameter fusion according to claim 3 is characterized in that: Step S33 further includes: S331, determine the Brillouin scattering peak position, select data points within a specified range near the peak for local analysis; around the selected data points, use a quadratic polynomial based on the least squares method to perform curve fitting to obtain a quadratic function that approximates the Brillouin scattering peak shape: p(F)=aF 2 +bF+c Where F is the frequency, and a, b, and c are the polynomial coefficients. The optimal fitting parameters are found by iteratively searching for the minimum residual sum of squares between the original data and the binomial function. The RSS calculation formula is: Among them, S i is the original data; when the peak position converges or reaches the preset upper limit of fitting times, the quadratic polynomial fitting is stopped to obtain the fitting peak point; S332, determining the precise value of the Brillouin peak frequency shift of the entire line based on the fitted peak point, and generating a Brillouin frequency shift curve for the entire line.

5. The method for rapid and accurate positioning of OPGW towers based on multi-dimensional parameter fusion according to claim 3 is characterized in that: Step S34 further includes: S341, designing a second sliding variance window based on the transmission voltage level of the line, the height of the tower, and the excess length of the optical cable at the connecting tower. The designed second sliding variance window is greater than the total length of the down conductor and the excess cable at a single connecting tower and less than the span of any section of the measurement line, so that each second sliding variance window contains only one connecting tower; using the second sliding variance window to segment the Brillouin frequency shift curve, and calculating the signal variance of each second sliding variance window; S342, using the mean of the variance of the second sliding window as a determination threshold, marking areas where the variance is lower than the determination threshold as potential abnormal areas, and considering that these areas may contain connection towers; S343: In each identified potential abnormal area, the center point of the sliding window corresponding to the maximum variance is considered to be the most accurate position of the BFS jump point; the variance result is analyzed using the peak finding algorithm, and the quadratic function fitting algorithm is used to fit the result to find the local variance peak point as the BFS abnormal point.

6. The method for rapid and accurate positioning of OPGW towers based on multi-dimensional parameter fusion according to claim 3, characterized in that: Step S35 further includes: S351, set a sliding window, with the Brillouin frequency shift anomaly point as the center and the BFS data of ±30m on the left and right as the window size, and split the array; S352, traverse the array, find all monotonic intervals, sort them by length, and extract the two longest monotonic intervals for use; S353 calculates the slopes of the two monotonic intervals and determines the slope threshold to distinguish normal fluctuations of the BFS signal from abnormal changes caused by peaks and jumps. Arrays with slopes below the slope threshold are cleared. The slope threshold is related to the spatial resolution of the monitoring equipment and the length of the affected optical cable segment caused by the structure of the monitored high-voltage overhead transmission line tower. S354, after completing the slope threshold determination, screen the remaining non-empty arrays; if there is no non-empty array, it proves that there is no reasonable peak or jump here, and this place is determined to be a noise point; if there is only one non-empty array here, it is determined to be a BFS jump point, corresponding to the preliminary positioning value of the connection tower with the frequency shift parameter as the carrier; if there are two non-empty monotonic arrays here, compare the slopes and orders of the two arrays. If the slopes of the two monotonic arrays are opposite, and the index of the array with a positive slope in the original array is greater than the array with a negative slope, it is considered that there is a peak here, corresponding to the preliminary positioning value of the tension tower with the strain parameter as the carrier and the preliminary positioning value of the straight tower with the temperature parameter as the carrier, otherwise this place is determined to be a noise point.

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