Pole-tower and optical cable positioning method based on distributed optical fiber sensing and topological matching

Abstract

This invention discloses a pole-to-optical cable positioning method based on distributed optical fiber sensing and topology matching, relating to the field of power communication optical cable operation and maintenance technology. The method includes: acquiring Brillouin frequency shift signals, ambient temperature, and icing thickness to perform signal denoising; calibrating the denoised signal to obtain a calibrated frequency shift signal; extracting the optical position of the optical cable at the pole's suspension point using the signal abrupt change characteristics of the suspension point and constructing a suspension point feature set; calculating a dynamic sag correction coefficient based on ambient temperature, icing thickness, and optical cable stress to convert the optical length of the optical cable to its actual geographical length; and establishing a three-dimensional mapping relationship to complete the optical cable location. This invention relies on BOTDA / BOTDR distributed optical fiber sensing equipment and OTDR equipment, and through a process logic of data acquisition, signal processing, dynamic correction, topology mapping, and self-healing update, achieves the associated positioning of poles and optical cables, solving the problem of inaccurate correspondence between the optical cable's optical position and the pole, and improving the accuracy of pole attribution.

Description

Technical Field

[0001] This invention relates to the field of power communication optical cable operation and maintenance technology, specifically a tower-optical cable positioning method based on distributed optical fiber sensing and topology matching. Background Technology

[0002] In the operation and maintenance of power grid transmission lines and OPGW optical cables, fault location, line status monitoring, and tower-to-cable topology correlation are core aspects of ensuring stable communication link operation. Current mainstream location methods primarily rely on OTDR (Optical Time Domain Reflectometer) and BOTDA / BOTDR distributed fiber optic sensing technology, but these have significant shortcomings in practical engineering applications. 1. The optical location of the optical cable is out of sync with the geographical location: OTDR can only measure the optical distance of the optical cable and cannot map the faulty optical location to the specific tower number and geographical coordinates. Maintenance personnel still need to manually check each tower, which results in low positioning efficiency and long repair time. 2. Insufficient accuracy of pole and tower anchoring points: Existing technologies mostly rely on instantaneous sensor peak values ​​or static ledgers to match pole and tower positions, without deeply exploring the rigid connection change characteristics of optical cables at pole and tower anchoring points. The anchoring basis is weak, which easily leads to misalignment between spans and incorrect pole and tower assignment. 3. Environmental interference causes positioning drift: The temperature difference between day and night and seasonal temperature difference in the field will cause Brillouin frequency shift signal drift. Traditional methods lack temperature adaptive calibration mechanism, resulting in fluctuation of positioning results and high fault misjudgment rate. 4. Large length conversion error: The sag correction of optical cables generally uses a fixed coefficient, which does not take into account the influence of dynamic working conditions such as temperature, icing, stress, and optical cable creep. The conversion error between the optical length of the optical cable and the actual geographical length continues to accumulate, which cannot meet the requirements of high-precision positioning. 5. Topology cannot be updated autonomously: After line renovation, optical cable splicing, tower settlement, and creep deformation, the original tower-optical cable mapping relationship becomes invalid. Manual on-site retesting and recalibration of the ledger are required, resulting in a large workload, high cost, and low level of intelligence in operation and maintenance. 6. Low data utilization and slow fault response: Distributed fiber optic sensing data is only used for simple threshold early warning and has not built an integrated topology system of "fiber optic cable-tower-geographic coordinates". After a fault occurs, it is impossible to quickly locate the relevant tower section, resulting in insufficient emergency response efficiency.

[0003] Based on this, a tower-cable positioning method based on distributed optical fiber sensing and topology matching is now provided, which can eliminate the drawbacks of existing technical solutions. Summary of the Invention

[0004] The purpose of this invention is to provide a pole-to-optical cable positioning method based on distributed optical fiber sensing and topology matching, in order to solve the problems of existing technologies in the background, such as the disconnect between the optical position and the geographical location of the optical cable, insufficient anchoring accuracy of the pole hanging point, positioning drift caused by environmental interference, large length conversion error, and inability to autonomously update the topology relationship.

[0005] To achieve the above objectives, the present invention provides the following technical solution: The pole-to-optical cable positioning method based on distributed optical fiber sensing and topology matching specifically includes the following steps: Step S1: Collect Brillouin frequency shift signals along the entire optical cable using BOTDA / BOTDR distributed optical fiber sensing equipment, collect the ambient temperature along the optical cable using an environmental monitoring terminal, calculate the icing thickness based on the ambient temperature, import the tower ledger and tower geographical coordinates to build a basic information database, and use the db4 wavelet threshold denoising algorithm to denoise the Brillouin frequency shift signals. Step S2: Establish a temperature adaptive calibration model and perform calibration on the denoised Brillouin frequency shift signal to eliminate the interference of ambient temperature on the Brillouin frequency shift signal. Perform signal stability judgment on the calibrated Brillouin frequency shift signal. If it is stable, proceed to step S3; otherwise, repeat the calibration operation. Step S3: Based on the calibrated Brillouin frequency shift signal, the abrupt change characteristics of the frequency shift signal at the pole hanging point are utilized. The abrupt change intensity of the frequency shift signal is calculated using the first-order difference method. Combined with the hanging point determination threshold, the optical position of the optical cable at the pole hanging point is determined. A hanging point feature set is constructed, which includes the optical position of the optical cable at the pole hanging point, the calibrated Brillouin frequency shift signal, the abrupt change intensity of the frequency shift signal, and the optical distance between adjacent pole hanging points. Step S4: Introduce a dynamic sag correction algorithm, combine ambient temperature, ice thickness and optical cable stress to calculate the dynamic sag correction coefficient, and use the dynamic sag correction coefficient to convert the optical cable optical length into the actual geographical length, thus completing the mapping from optical distance to geographical distance. Step S5: Based on the optical position of the optical cable at the tower attachment point, the optical distance between adjacent tower attachment points and the geographical coordinates of the tower, establish a three-in-one mapping relationship between the optical cable optical position, tower number and geographical coordinates. Through tower ownership determination and linear interpolation calculation, output the tower number, tower range and geographical coordinates corresponding to any optical cable optical position. Step S6: Collect the scattered signal of the optical cable under fault state through OTDR device, extract the optical position of the optical cable at the fault point and calculate the loss change, generate the judgment condition for determining the fault type based on the loss change, substitute the optical position of the optical cable at the fault point into the three-in-one mapping relationship, combine the topology mapping to locate the fault-attributed tower and geographical distance, and realize the fault type identification based on the fault signal characteristics and judgment conditions. Step S7: Calculate the optical position offset of the optical cable at the tower suspension point in real time based on the optical position of the optical cable at the tower suspension point. When the offset reaches the update threshold, combine the similarity of the suspension point feature set and perform gradual or abrupt updates according to the gradual or abrupt working conditions to complete the tower-optical cable topology alignment.

[0006] Furthermore, the formula for acquiring the Brillouin frequency shift signal in step S1 is: ; in, for Time-of-flight optical position Brillouin frequency shift at that location The reference frequency shift is under stress-free, standard temperature conditions. The stress-frequency shift coefficient of the optical cable. for Time-of-flight optical position The stress on the optical cable at the location, The ambient temperature-frequency shift coefficient, for Time-of-flight optical position The ambient temperature; The formula for calculating the ice thickness is: ; in, for The thickness of the icing on the optical cable at all times. Standard icing thickness, The coefficient representing the influence of icing temperature. This is the critical temperature for icing. for ambient temperature at all times It is an exponential function.

[0007] Furthermore, in step S1, the db4 wavelet threshold denoising algorithm is used to denoise the Brillouin frequency shift signal, as expressed by the formula: ; in, The denoised Brillouin frequency shift signal. For symbolic functions, The original Brillouin frequency shift signal, The threshold for wavelet denoising.

[0008] Furthermore, in step S2, the denoised Brillouin frequency shift signal is calibrated to eliminate the interference of ambient temperature on the Brillouin frequency shift signal, as expressed by the formula: ; in, This is the temperature-calibrated Brillouin frequency shift signal. Standard reference temperature; The signal stability of the calibrated Brillouin frequency shift signal is determined using the following formula: ; in, To determine the standard deviation of the calibrated Brillouin frequency shift signal, For the number of samples, For the first Sampling time, For the first time after temperature calibration Subsampled Brillouin frequency shift signal Optical position of optical cable The average value of the Brillouin shift signal after calibration.

[0009] Furthermore, step S3 specifically includes: The intensity of abrupt changes in frequency-shifted signals is calculated using the first-order difference method. The formula is as follows: ,in, for Time-of-flight optical position The intensity of the frequency shift signal abruptly changes at that point. The sampling step size, for Time-of-flight optical position The Brillouin frequency shift signal after temperature calibration at the location, for Time-of-flight optical position The Brillouin frequency shift signal after temperature calibration at the location; The optical position of the optical cable at the pole attachment point is determined by combining the attachment point determination threshold, specifically as follows: Using the temperature-calibrated Brillouin frequency shift signal as input, a first-order differential operation is performed along the optical length of the optical cable to obtain a first-order differential sequence of the frequency shift signal along the entire optical cable. This first-order differential sequence is the differential signal, and the absolute value of the differential signal is the intensity of the frequency shift signal abrupt change. Based on the differential signal, the snagging point determination threshold is calculated using the following formula: ,in, The threshold for determining the hanging point is the threshold for the intensity of the sudden change at the hanging point. This represents the average value of the first-order difference sequence of the frequency shift signal along the entire optical cable. The standard deviation of the differential signal; Perform the operation of determining the optical position of the fiber optic cable at the pole / tower mounting point: When At that time, determine the optical position of the optical cable The location is the optical position of the fiber optic cable at the pole / tower mounting point. , The tower number; Simultaneously, feature parameters of the tower suspension point are extracted to construct a suspension point feature set, which includes the optical position of the optical cable at the tower suspension point, the calibrated Brillouin frequency shift signal, the intensity of the frequency shift signal abrupt change, and the optical distance between adjacent tower suspension points. The suspension point feature set is represented as follows: ; in, For the first The feature set of the base tower hanging points This is the Brillouin frequency shift signal after temperature calibration at the hanging point. The signal abrupt change amplitude at the hanging point and satisfying , for The intensity of the frequency shift signal abrupt change at the moment of attachment. For the first Base tower hanging point and the first Optical distance between the anchor points of the base tower.

[0010] Furthermore, the dynamic sag correction algorithm in step S4 is expressed by the following formula: ; in, for The dynamic sag correction factor at time t, The coefficient representing the influence of ambient temperature on sag. The coefficient representing the influence of icing thickness on sag. This is the coefficient representing the influence of optical cable stress on sag. for Average stress along the entire optical cable at any given time; The optical length of the fiber optic cable is converted to its actual geographical length using a dynamic sag correction factor, expressed by the formula: ,in, for Time-of-flight optical position The corresponding actual geographical length, for At the same time, the optical position of the optical cable The corresponding optical length of the optical cable.

[0011] Furthermore, the geographical coordinates of the tower in step S1 are represented using the CGCS2000 coordinate system. ,in, For the first Longitude of the base tower For the first The latitude of the base tower, For the first The altitude of the base tower.

[0012] Further, step S5 specifically includes: Perform pole / tower attribution determination operation: for any optical cable optical position Calculate the optical position of the optical cable relative to each tower mounting point. The absolute distance is used to determine the assigned tower, and the calculation formula is as follows: ,in, Optical position of optical cable The corresponding tower number, This means taking the option that minimizes the distance. value; Perform linear interpolation calculation: Based on the geographical coordinates of the host tower and adjacent towers, calculate the optical position of the optical cable through linear interpolation. The corresponding actual geographic coordinates are calculated using the following formula: ; in, , , Composition of optical fiber cable optical position Corresponding geographic coordinates , , , Composition of the first Geographic coordinates of the base tower , , , Composition of the first Geographic coordinates of the base tower , For the first Base tower hanging point and the first Optical distance between base pole / tower hanging points; Optical position of output optical cable The corresponding tower number, tower range, and geographical coordinates are used to achieve the positioning effect.

[0013] Further, step S6 specifically includes: When optical cables experience faults such as fiber breakage, abnormal attenuation, or stress overload, OTDR equipment is used to collect scattered signals under fault conditions and extract the optical location of the optical cable at the fault point. The change in loss is calculated, and the formula for calculating the change in loss is: ,in, This represents the difference in wear and tear between the faulty state and the normal state. The loss value at the fault point. This is the baseline value for loss under normal conditions; Optical position of the fault point optical cable Substituting the three-in-one mapping relationship, perform pole attribution determination and linear interpolation calculation to determine the pole to which the fault belongs and its geographical coordinates, and calculate the actual distance between the fault point and the pole. The calculation formula is as follows: ,in, The distance from the fault point to the first The actual geographical distance of the base tower The actual geographical length of the fault location. For the first The actual geographical length of the base pole / tower anchor point; The fault types include at least optical cable breakage, abnormal attenuation, icing effects, and tower structural abnormalities. The specific judgment criteria include: when And the amplitude of the reflected signal drops sharply to 0, that is At that time, it was determined that the optical cable was broken. The amplitude of the OTDR reflected signal at the fault point; when And the reflected signal is stable, satisfying When this occurs, it is determined to be abnormal attenuation. The standard deviation of the reflected signal; when Furthermore, the frequency shift changes uniformly across the entire range, satisfying... At that time, it was determined to be due to the impact of icing. for The thickness of the icing on the optical cable at all times. The standard deviation of the Brillouin frequency shift signal after calibration; When a single-point frequency shift changes abruptly And this point corresponds to the pole's anchor point, and the pole's tilt is also... At that time, it was determined that the tower structure was abnormal. For the first The tilt angle of the base tower.

[0014] Furthermore, the formula for calculating the offset in step S7 is as follows: ,in, for Time of the first Optical position offset of the optical cable at the base tower suspension point for The optical position of the fiber optic cable is constantly being monitored. The initial reference point for the optical cable's optical position; The formula for calculating the similarity of the hanging point feature set is as follows: ,in, To update the similarity of the feature sets of hanging points before and after, for Time of the first The feature set of the base tower hanging points For the initial feature set, The number of samples.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention extracts the suspension point by exploiting the abrupt change characteristics of the Brillouin frequency shift signal at the tower attachment point and using first-order difference and threshold determination, replacing the traditional instantaneous peak matching. This solves the problem of inaccurate correspondence between the optical cable optical position and the tower and improves the accuracy of tower attribution. 2. The present invention is equipped with a temperature adaptive calibration model to eliminate the drift interference of the Brillouin frequency shift signal caused by the ambient temperature difference, so that the positioning can still be stable under complex weather conditions, reducing the fault misjudgment rate. In addition, it adopts a dynamic sag correction coefficient that integrates ambient temperature, ice thickness and optical cable stress to adapt to the line operation conditions in real time, effectively reducing the conversion error between optical cable optical length and actual geographical length. 3. This invention constructs a three-in-one mapping relationship between optical cable optical location, tower number, and geographical coordinates, which can directly output the tower, span, and geographical coordinates of the fault point without manual secondary calculation, and supports gradual updates for gradual working conditions and sudden updates for sudden working conditions. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the method steps of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0018] To address the shortcomings of existing technologies, such as the disconnect between optical cable optical position and geographical location, insufficient anchoring accuracy of tower hanging points, positioning drift caused by environmental interference, large length conversion errors, and inability to autonomously update topology relationships, etc. Figure 1 As shown, this invention provides a pole-to-cable positioning method based on distributed optical fiber sensing and topology matching. Relying on BOTDA / BOTDR distributed optical fiber sensing equipment, OTDR testing equipment, and a GIS geographic information system (all existing data acquisition devices), it achieves the associated positioning of poles and optical cables through a complete process logic of "data acquisition - signal processing - dynamic correction - topology mapping - self-healing update." Specifically, it includes the following steps: Step S1: Collect Brillouin frequency shift signals along the entire optical cable using BOTDA / BOTDR distributed optical fiber sensing equipment, collect the ambient temperature along the optical cable using an environmental monitoring terminal, calculate the icing thickness based on the ambient temperature, import the tower ledger and tower geographical coordinates to build a basic information database, and use the db4 wavelet threshold denoising algorithm to denoise the Brillouin frequency shift signals. Distributed fiber optic sensing technologies such as BOTDA (Brillouin Optical Time Domain Analysis) and BOTDR (Brillouin Optical Time Domain Reflectometry) rely on the Brillouin scattering principle to obtain frequency shift data along the entire optical cable, thereby enabling continuous distributed monitoring of optical cable stress and temperature parameters. Step S2: Establish a temperature adaptive calibration model and perform calibration on the denoised Brillouin frequency shift signal to eliminate the interference of ambient temperature on the Brillouin frequency shift signal. Perform signal stability judgment on the calibrated Brillouin frequency shift signal. If it is stable, proceed to step S3; otherwise, repeat the calibration operation. Step S3: Based on the calibrated Brillouin frequency shift signal, the abrupt change characteristics of the frequency shift signal at the pole hanging point are utilized. The abrupt change intensity of the frequency shift signal is calculated using the first-order difference method. Combined with the hanging point determination threshold, the optical position of the optical cable at the pole hanging point is determined. A hanging point feature set is constructed, which includes the optical position of the optical cable at the pole hanging point, the calibrated Brillouin frequency shift signal, the abrupt change intensity of the frequency shift signal, and the optical distance between adjacent pole hanging points. Step S4: Introduce a dynamic sag correction algorithm, combine ambient temperature, ice thickness and optical cable stress to calculate the dynamic sag correction coefficient, and use the dynamic sag correction coefficient to convert the optical cable optical length into the actual geographical length, thus completing the mapping from optical distance to geographical distance. Step S5: Based on the optical position of the optical cable at the tower attachment point, the optical distance between adjacent tower attachment points and the geographical coordinates of the tower, establish a three-in-one mapping relationship between the optical cable optical position, tower number and geographical coordinates. Through tower ownership determination and linear interpolation calculation, output the tower number, tower range and geographical coordinates corresponding to any optical cable optical position. Step S6: Collect the scattered signals of the optical cable under fault conditions such as fiber breakage, abnormal attenuation, and stress overload using an OTDR device, extract the optical position of the optical cable at the fault point and calculate the loss change, generate judgment conditions for determining the fault type based on the loss change, substitute the optical position of the optical cable at the fault point into the three-in-one mapping relationship, combine the topology mapping to locate the fault-attributed tower and geographical distance, and realize the fault type identification based on the fault signal characteristics and judgment conditions. Step S7: Calculate the optical position offset of the optical cable at the tower suspension point in real time based on the optical position of the optical cable at the tower suspension point. When the offset reaches the update threshold, combine the similarity of the suspension point feature set and perform gradual or abrupt updates according to the gradual or abrupt working conditions to complete the tower-optical cable topology alignment. The above steps S1 to S5 only complete the static and basic pole-to-optical cable location mapping, which is the minimum implementation of "able to locate, but unreliable, unusable, and unsustainable". Step S6 is used to realize the engineering implementation of the location results and the fault closure loop. Step S7 is a long-term guarantee operation for the pole-to-optical cable location relationship.

[0019] Specifically, step S1 includes: Brillouin frequency shift signals along the entire optical cable are collected using BOTDA / BOTDR distributed optical fiber sensing equipment, and the signal acquisition timestamps are recorded synchronously. The acquisition formula is as follows: ; in, for Time-of-flight optical position Brillouin shift at GHz (unit: GHz) The reference frequency shift (in GHz) is under stress-free, standard temperature (25°C) conditions. The stress-frequency shift coefficient of the optical cable (unit: GHz / MPa). for Time-of-flight optical position The stress in the optical cable at the location (in MPa). The ambient temperature-frequency shift coefficient (unit: GHz / ℃) is the frequency shift factor. for Time-of-flight optical position Ambient temperature (in °C); The ambient temperature along the optical cable is collected by an environmental monitoring terminal, and the icing thickness is calculated based on the ambient temperature. The formula for calculating the icing thickness is as follows: ; in, for Ice thickness of optical fiber cable at any time (in mm). Standard icing thickness (in mm). The coefficient representing the influence of icing temperature. The critical temperature for icing (0℃). for Ambient temperature at any time (in °C). It is an exponential function; Import the pole and tower ledger and their geographic coordinates to build a basic information database. The geographic coordinates of the poles and towers adopt the CGCS2000 coordinate system and are represented as follows: ,in, For the first Longitude of the base tower (in degrees). For the first The latitude of the base tower (in degrees). For the first The elevation of the base tower (in meters); The db4 wavelet threshold denoising algorithm is used to denoise the acquired Brillouin frequency shift signal. The calculation formula for denoising is as follows: ; in, This is the denoised Brillouin frequency shift signal (in GHz). This is a sign function; it returns 1 for positive numbers, -1 for negative numbers, and 0 for zero. This is the original Brillouin frequency shift signal (in GHz). The wavelet denoising threshold is obtained from historical data statistics and is usually set to 0.01~0.03GHz; Step S1 is used for real-time acquisition and preprocessing of multi-source data.

[0020] Specifically, step S2 includes: Considering that traditional pole-to-fiber optic cable matching positioning methods rely heavily on instantaneous sensor peak values ​​and static records for point-to-point correspondence, lacking a temperature adaptive compensation mechanism, and that day-night and seasonal temperature differences in the field easily cause Brillouin frequency shift signal drift, directly leading to fluctuations in positioning results and frequent misjudgments, this invention establishes a temperature adaptive calibration model to calibrate the denoised Brillouin frequency shift signal to eliminate the interference of ambient temperature on the frequency shift signal. The calibration formula is as follows: ; in, This is the temperature-calibrated Brillouin frequency shift signal (in GHz). The standard reference temperature is 25°C. The signal stability of the calibrated Brillouin frequency shift signal is determined using the following formula: ; in, The standard deviation (in GHz) of the calibrated Brillouin shift signal. For the number of samples, For the first Sampling time, For the first time after temperature calibration Subsampled Brillouin frequency shift signal (in GHz). Optical position of optical cable The average value (in GHz) of the Brillouin frequency shift signal after calibration. If the signal is stable at GHz, proceed to the next step; otherwise, recalibrate. According to step S2, in order to solve the problem of monitoring signal drift and unstable positioning results caused by temperature changes, this invention establishes a temperature adaptive calibration model to eliminate the interference of environmental temperature difference on the sensing signal and ensure positioning accuracy and stability.

[0021] Specifically, step S3 includes: Considering that the tower suspension point is a rigid connection point between the optical cable and the tower, and its frequency shift signal exhibits abrupt changes, this invention employs a first-order difference method to extract the optical position of the optical cable at the suspension point, specifically expressed as follows: The intensity of abrupt changes in frequency-shifted signals is calculated using the first-order difference method. The calculation formula includes: ; in, for Time-of-flight optical position The intensity of the frequency shift signal change at a given location (in GHz). The sampling step size (in meters) is 2 to 3 times the sampling interval of the optical cable (usually 2 meters). for Time-of-flight optical position Temperature-calibrated Brillouin frequency shift signal (in GHz). for Time-of-flight optical position The Brillouin frequency shift signal after temperature calibration at the location; The optical position of the optical cable at the pole attachment point is determined by combining the attachment point determination threshold, specifically as follows: Using the temperature-calibrated Brillouin frequency shift signal as input, a first-order differential operation is performed along the optical length of the optical cable to obtain the first-order differential sequence of the frequency shift signal along the entire optical cable. The first-order differential sequence is the differential signal, and the absolute value of the differential signal is the intensity of the frequency shift signal abrupt change. Based on the differential signal, the snagging point determination threshold is calculated using the following formula: ; in, The threshold for determining the hanging point is the threshold for the intensity of sudden changes at the hanging point (in GHz). It represents the average value (in GHz) of the first-order differential sequence of the frequency shift signal along the entire optical cable. The standard deviation of the differential signal (in GHz); Perform the operation of determining the optical position of the fiber optic cable at the pole / tower mounting point: When At that time, determine the optical position of the optical cable The location is the optical position of the fiber optic cable at the pole / tower mounting point. , Given the tower number, traverse the entire optical cable line. When the frequency shift signal abrupt change intensity at a certain optical cable optical position is greater than the suspension point determination threshold, determine that position as a tower suspension point. Simultaneously, feature parameters of the tower suspension point are extracted to construct a suspension point feature set, which includes the optical position of the optical cable at the tower suspension point, the calibrated Brillouin frequency shift signal, the intensity of the frequency shift signal abrupt change, and the optical distance between adjacent tower suspension points. The suspension point feature set is represented as follows: ; in, For the first The feature set of the base tower hanging points The Brillouin frequency shift signal (in GHz) after temperature calibration at the hanging point. The signal abrupt change amplitude at the hanging point and satisfying (Unit: GHz) for The intensity of the frequency shift signal change at the moment of attachment (in GHz). For the first Base tower hanging point and the first Optical distance between base tower suspension points (in meters); According to step S3, in order to address the problems of weak anchoring basis and insufficient positioning accuracy in existing methods, this invention constructs anchoring logic by exploring the inherent abrupt change characteristics of the frequency shift signal of the tower hanging point, thereby achieving a precise correspondence between the optical position of the optical cable and the position of the tower.

[0022] Specifically, step S4 includes: Considering that existing optical cable sag length conversions generally use fixed correction factors, directly converting the optical cable length to the actual geographical length, this approach fails to fully account for dynamic influencing factors such as environmental temperature fluctuations, long-term creep aging of the optical cable, on-site redundant coiling, and weather load deformation. The cumulative error caused by sag stretching and coiling accumulation continuously increases, resulting in low accuracy in mapping optical ranging to actual geographical coordinates, which cannot meet the high-precision positioning requirements of power grid operation and maintenance. Therefore, this invention adopts a condition-adaptive dynamic sag correction algorithm, introducing a dynamic sag correction factor to achieve a better conversion effect between the optical cable length and the actual geographical length. The dynamic sag correction algorithm is expressed by the formula: ; in, for The dynamic sag correction factor at time t, The influence coefficient of ambient temperature on sag (unit: 1 / ℃, value: 0.0005 / ℃). The coefficient representing the effect of icing thickness on sag (unit: 1 / mm, value: 0.0003 / mm). The coefficient representing the influence of optical cable stress on sag (unit: 1 / MPa, value: 0.0002 / MPa). for Average stress along the entire optical cable at any given time (unit: MPa). The optical length of the fiber optic cable is converted to its actual geographical length using a dynamic sag correction factor, expressed by the formula: ,in, for Time-of-flight optical position The corresponding actual geographical length (in meters). for Time-of-flight optical position The corresponding optical cable length (in meters); As can be seen from step S4, in order to overcome the problem of large length conversion error caused by the traditional fixed sag coefficient, the present invention adopts a dynamic sag correction algorithm that is adjusted in real time according to the working conditions to improve the accuracy of the conversion between the optical length of the optical cable and the actual geographical length.

[0023] Specifically, step S5 includes: Considering that distributed fiber optic sensing technologies such as BOTDA (Brillouin Optical Time Domain Analysis) and BOTDR (Brillouin Optical Time Domain Reflectometry) often use monitoring data for simple judgments such as line over-limit early warning, without deeply exploring the inherent abrupt changes in the sensing signals corresponding to the tower mounting points, and without establishing a stable and reusable tower-fiber cable matching and association logic, the monitoring data has a single application dimension and low resource utilization. Therefore, this invention establishes a three-in-one mapping relationship between the optical position of the fiber optic cable, the tower number, and the geographical coordinates, to achieve the positioning effect from the optical position of the fiber optic cable to the tower and geographical coordinates. The specific process is as follows: Perform pole / tower attribution determination operation: for any optical cable optical position Calculate the optical position of the optical cable relative to each tower mounting point. The absolute distance is used to determine the assigned tower, and the calculation formula is as follows: ,in, Optical position of optical cable The corresponding tower number, This means taking the option that minimizes the distance. value; Perform linear interpolation calculation: Based on the geographical coordinates of the host tower and adjacent towers, calculate the optical position of the optical cable through linear interpolation. The corresponding actual geographic coordinates are calculated using the following formula: ; in, , , Composition of optical fiber cable optical position Corresponding geographic coordinates , , , Composition of the first Geographic coordinates of the base tower , , , Composition of the first Geographic coordinates of the base tower , For the first Base tower hanging point and the first Optical distance between base tower suspension points (in meters); Output positioning result: Optical position of the output optical cable The corresponding tower number, tower range, and geographical coordinates are used to achieve positioning. As can be seen from step S5: In response to the problem that optical distance cannot be mapped to specific towers and geographical coordinates, this invention establishes a three-in-one mapping relationship between optical cable optical location, tower number, and geographical coordinates, realizing spatial matching that can be directly used for operation and maintenance practice.

[0024] Specifically, step S6 includes: When optical cables experience faults such as fiber breakage, abnormal attenuation, or stress overload, the fault location method of this invention enables rapid fault point location and automatic fault type identification. The specific formulas and steps are as follows: By acquiring the scattered signal under fault conditions using an OTDR device, the optical position of the optical cable at the fault point can be extracted. And calculate the loss change. OTDR (Optical Time Domain Reflectometer) is a routine testing device in the operation and maintenance of power communication optical cables. By emitting light pulses and detecting backscattered signals, it can measure the length of optical cables and the optical position of fault points in optical cables, and obtain pure optical distance data. The formula for calculating the change in loss is: ,in, This represents the difference in losses between the fault state and the normal state (in dB / km). The loss value at the fault point (unit: dB / km). The loss baseline value under normal conditions (unit: dB / km); Optical position of the fault point optical cable Substituting the three-in-one mapping relationship and the formula for determining tower attribution and calculating geographical coordinates, we perform tower attribution determination and linear interpolation calculation to determine the tower to which the fault belongs and its geographical coordinates. We then calculate the actual distance between the fault point and the tower using the following formula: ,in, The distance from the fault point to the first The actual geographical distance of the base tower (in meters). The actual geographical length of the fault location (in meters). For the first The actual geographical length of the base pole hanging point (in meters); Fault types include at least optical cable breakage, abnormal attenuation, icing effects, and tower structural abnormalities. Based on fault signal characteristics and combined with judgment criteria, fault type identification is achieved. The judgment criteria specifically include: when And the amplitude of the reflected signal drops sharply to 0, that is At that time, it was determined that the optical cable was broken. The amplitude of the OTDR reflected signal at the fault point; when And the reflected signal is stable, satisfying When this occurs, it is determined to be abnormal attenuation. The standard deviation of the reflected signal; when Furthermore, the frequency shift changes uniformly across the entire range, satisfying... At that time, it was determined to be due to the impact of icing; When a single-point frequency shift changes abruptly And this point corresponds to the hanging point location, while the tower tilt amount At that time, it was determined that the tower structure was abnormal. For the first The tilt angle of the base tower.

[0025] Specifically, step S7 includes: Considering that existing tower status monitoring mostly focuses on individual towers as independent monitoring objects, primarily collecting operational data such as tower tilt and local deformation, and that each tower monitoring unit is isolated from the others, without constructing a fully integrated tower-optical cable topology correspondence system, it is difficult to quickly identify and pinpoint the tower section to which the fault belongs when optical cables experience faults such as fiber breakage, abnormal attenuation, or abnormal deformation. Fault diagnosis still relies on manual full-line inspection, resulting in low response efficiency and high maintenance costs. Therefore, this invention addresses scenarios such as line renovation, optical cable splicing, and tower settlement by achieving automatic self-healing updates of the tower-optical cable topology relationship without manual intervention. Specifically, it is expressed as follows: Offset Calculation: Calculate the offset of the optical position of the suspending fiber optic cable in real time to determine whether a topology update is triggered. ,in, for Time of the first Optical position offset of the optical cable at the base tower suspension point (in meters). for Optical position of the fiber optic cable at all times (in meters). The initial reference point optical position of the optical cable (in meters); Update trigger condition: when At that time, a topology update is triggered. To update the threshold, for example, take 0.5m; Gradual updates (adapting to gradually changing operating conditions, such as fiber optic cable creep and slow tower settlement): ; in, This is the reference position of the hanging point at the next moment (in meters). This is the update factor (taken as 0.8~0.9) to avoid over-updating; Sudden-break updates (adapting to sudden changes in operating conditions, such as fiber optic cable splicing and line upgrades): ; in, To update the similarity of the feature sets of hanging points before and after, for Time of the first The feature set of the base tower hanging points As the initial feature set, through A similarity calculation is performed between the current tower hanging point feature set and the initial feature set to determine whether the topology needs to be updated. At that time, the topology mapping relationship is reconstructed, the attachment point location and geographic coordinates are updated synchronously, and the topology alignment is completed; According to step S7, this invention addresses the pain points of fiber optic cable creep, tower settlement, and the need for manual recalibration of records after line maintenance. It achieves automatic self-healing and updating of the tower-fiber optic cable topology, significantly reducing the workload of manual on-site maintenance.

[0026] In summary, this invention effectively solves the problems of inaccurate anchoring of tower-optical cable points and temperature drift interference in existing technologies through closed-loop processing including multi-source data acquisition, temperature adaptive calibration, tower hanging point feature extraction, dynamic sag correction, three-in-one topology mapping, fault identification, and topology self-healing update. This invention fully leverages the inherent characteristics of distributed optical fiber sensing signals to achieve precise matching between the optical cable's optical position and the tower and geographical coordinates, facilitating the reduction of optical cable maintenance costs and improving the speed of emergency response to faults.

[0027] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A pole-to-optical cable positioning method based on distributed optical fiber sensing and topology matching, characterized in that, Specifically, the following steps are included: Step S1: Collect Brillouin frequency shift signals along the entire optical cable using BOTDA / BOTDR distributed optical fiber sensing equipment, collect the ambient temperature along the optical cable using an environmental monitoring terminal, calculate the icing thickness based on the ambient temperature, import the tower ledger and tower geographical coordinates to build a basic information database, and use the db4 wavelet threshold denoising algorithm to denoise the Brillouin frequency shift signals. Step S2: Establish a temperature adaptive calibration model and perform calibration on the denoised Brillouin frequency shift signal to eliminate the interference of ambient temperature on the Brillouin frequency shift signal. Perform signal stability judgment on the calibrated Brillouin frequency shift signal. If it is stable, proceed to step S3; otherwise, repeat the calibration operation. Step S3: Based on the calibrated Brillouin frequency shift signal, the abrupt change characteristics of the frequency shift signal at the pole hanging point are utilized. The abrupt change intensity of the frequency shift signal is calculated using the first-order difference method. Combined with the hanging point determination threshold, the optical position of the optical cable at the pole hanging point is determined. A hanging point feature set is constructed, which includes the optical position of the optical cable at the pole hanging point, the calibrated Brillouin frequency shift signal, the abrupt change intensity of the frequency shift signal, and the optical distance between adjacent pole hanging points. Step S4: Introduce a dynamic sag correction algorithm, combine ambient temperature, ice thickness and optical cable stress to calculate the dynamic sag correction coefficient, and use the dynamic sag correction coefficient to convert the optical cable optical length into the actual geographical length, thus completing the mapping from optical distance to geographical distance. Step S5: Based on the optical position of the optical cable at the tower attachment point, the optical distance between adjacent tower attachment points and the geographical coordinates of the tower, establish a three-in-one mapping relationship between the optical cable optical position, tower number and geographical coordinates. Through tower ownership determination and linear interpolation calculation, output the tower number, tower range and geographical coordinates corresponding to any optical cable optical position. Step S6: Collect the scattered signal of the optical cable under fault state through OTDR device, extract the optical position of the optical cable at the fault point and calculate the loss change, generate the judgment condition for determining the fault type based on the loss change, substitute the optical position of the optical cable at the fault point into the three-in-one mapping relationship, combine the topology mapping to locate the fault-attributed tower and geographical distance, and realize the fault type identification based on the fault signal characteristics and judgment conditions. Step S7: Calculate the optical position offset of the optical cable at the tower suspension point in real time based on the optical position of the optical cable at the tower suspension point. When the offset reaches the update threshold, combine the similarity of the suspension point feature set and perform gradual or abrupt updates according to the gradual or abrupt working conditions to complete the tower-optical cable topology alignment.

2. The pole-to-optical cable positioning method based on distributed optical fiber sensing and topology matching according to claim 1, characterized in that, The formula for acquiring the Brillouin frequency shift signal in step S1 is as follows: ； in, for Time-of-flight optical position Brillouin frequency shift at that location The reference frequency shift is under stress-free, standard temperature conditions. The stress-frequency shift coefficient of the optical cable. for Time-of-flight optical position The stress on the optical cable at the location, The ambient temperature-frequency shift coefficient, for Time-of-flight optical position The ambient temperature; The formula for calculating the ice thickness is: ； in, for The thickness of the icing on the optical cable at all times. Standard icing thickness, The coefficient representing the influence of icing temperature. This is the critical temperature for icing. for ambient temperature at all times It is an exponential function.

3. The pole-to-optical cable positioning method based on distributed optical fiber sensing and topology matching according to claim 2, characterized in that, In step S1, the db4 wavelet threshold denoising algorithm is used to denoise the Brillouin frequency shift signal, which can be expressed by the following formula: ; in, The denoised Brillouin frequency shift signal. For symbolic functions, The original Brillouin frequency shift signal, The threshold for wavelet denoising.

4. The pole-to-optical cable positioning method based on distributed optical fiber sensing and topology matching according to claim 3, characterized in that, In step S2, the denoised Brillouin frequency shift signal is calibrated to eliminate the interference of ambient temperature on the Brillouin frequency shift signal, which can be expressed by the formula: ; in, This is the temperature-calibrated Brillouin frequency shift signal. Standard reference temperature; The signal stability of the calibrated Brillouin frequency shift signal is determined using the following formula: ； in, To determine the standard deviation of the calibrated Brillouin frequency shift signal, For the number of samples, For the first Sampling time, For the first time after temperature calibration Subsampled Brillouin frequency shift signal Optical position of optical cable The average value of the Brillouin shift signal after calibration.

5. The pole-to-optical cable positioning method based on distributed optical fiber sensing and topology matching according to claim 1, characterized in that, Step S3 specifically includes: The intensity of abrupt changes in frequency-shifted signals is calculated using the first-order difference method. The formula is as follows: ,in, for Time-of-flight optical position The intensity of the frequency shift signal abruptly changes at that point. The sampling step size, for Time-of-flight optical position The Brillouin frequency shift signal after temperature calibration at the location, for Time-of-flight optical position The Brillouin frequency shift signal after temperature calibration at the location; The optical position of the optical cable at the pole attachment point is determined by combining the attachment point determination threshold, specifically as follows: Using the temperature-calibrated Brillouin frequency shift signal as input, a first-order differential operation is performed along the optical length of the optical cable to obtain a first-order differential sequence of the frequency shift signal along the entire optical cable. This first-order differential sequence is the differential signal, and the absolute value of the differential signal is the intensity of the frequency shift signal abrupt change. Based on the differential signal, the snagging point determination threshold is calculated using the following formula: ,in, The threshold for determining the hanging point is the threshold for the intensity of the sudden change at the hanging point. This represents the average value of the first-order difference sequence of the frequency shift signal along the entire optical cable. The standard deviation of the differential signal; Perform the operation of determining the optical position of the fiber optic cable at the pole / tower mounting point: When At that time, determine the optical position of the optical cable The location is the optical position of the fiber optic cable at the pole / tower mounting point. , The tower number; Simultaneously, feature parameters of the tower suspension point are extracted to construct a suspension point feature set, which includes the optical position of the optical cable at the tower suspension point, the calibrated Brillouin frequency shift signal, the intensity of the frequency shift signal abrupt change, and the optical distance between adjacent tower suspension points. The suspension point feature set is represented as follows: ； in, For the first The feature set of the base tower hanging points This is the Brillouin frequency shift signal after temperature calibration at the hanging point. The signal abrupt change amplitude at the hanging point and satisfying , for The intensity of the frequency shift signal abrupt change at the moment of attachment. For the first Base tower hanging point and the first Optical distance between the anchor points of the base tower.

6. The pole-to-optical cable positioning method based on distributed optical fiber sensing and topology matching according to claim 2, characterized in that, The dynamic sag correction algorithm in step S4 is expressed by the following formula: ； in, for The dynamic sag correction factor at time t, The coefficient representing the influence of ambient temperature on sag. The coefficient representing the influence of icing thickness on sag. This is the coefficient representing the influence of optical cable stress on sag. for Average stress along the entire optical cable at any given time; The optical length of the fiber optic cable is converted to its actual geographical length using a dynamic sag correction factor, expressed by the formula: ,in, for Time-of-flight optical position The corresponding actual geographical length, for At the same time, the optical position of the optical cable The corresponding optical length of the optical cable.

7. The pole-to-optical cable positioning method based on distributed optical fiber sensing and topology matching according to claim 1, characterized in that, The geographical coordinates of the tower in step S1 are expressed in the CGCS2000 coordinate system as follows: ,in, For the first Longitude of the base tower For the first The latitude of the base tower, For the first The altitude of the base tower.

8. The pole-to-optical cable positioning method based on distributed optical fiber sensing and topology matching according to claim 7, characterized in that, Step S5 specifically includes: Perform pole / tower attribution determination operation: for any optical cable optical position Calculate the optical position of the optical cable relative to each tower mounting point. The absolute distance is used to determine the assigned tower, and the calculation formula is as follows: ,in, Optical position of optical cable The corresponding tower number, This means taking the option that minimizes the distance. value; Perform linear interpolation calculation: Based on the geographical coordinates of the host tower and adjacent towers, calculate the optical position of the optical cable through linear interpolation. The corresponding actual geographic coordinates are calculated using the following formula: ； in, , , Composition of optical fiber cable optical position Corresponding geographic coordinates , , , Composition of the first Geographic coordinates of the base tower , , , Composition of the first Geographic coordinates of the base tower , For the first Base tower hanging point and the first Optical distance between base pole / tower hanging points; Optical position of output optical cable The corresponding tower number, tower range, and geographical coordinates are used to achieve the positioning effect.

9. The pole-to-optical cable positioning method based on distributed optical fiber sensing and topology matching according to claim 8, characterized in that, Step S6 specifically includes: When optical cables experience faults such as fiber breakage, abnormal attenuation, or stress overload, OTDR equipment is used to collect scattered signals under fault conditions and extract the optical location of the optical cable at the fault point. The change in loss is calculated, and the formula for calculating the change in loss is: ,in, This represents the difference in wear and tear between the faulty state and the normal state. The loss value at the fault point. This is the baseline value for loss under normal conditions; Optical position of the fault point optical cable Substituting the three-in-one mapping relationship, perform pole attribution determination and linear interpolation calculation to determine the pole to which the fault belongs and its geographical coordinates, and calculate the actual distance between the fault point and the pole. The calculation formula is as follows: ,in, The distance from the fault point to the first The actual geographical distance of the base tower The actual geographical length of the fault location. For the first The actual geographical length of the base pole / tower anchor point; The fault types include at least optical cable breakage, abnormal attenuation, icing effects, and tower structural abnormalities. The specific judgment criteria include: when And the amplitude of the reflected signal drops sharply to 0, that is At that time, it was determined that the optical cable was broken. The amplitude of the OTDR reflected signal at the fault point; when And the reflected signal is stable, satisfying When this occurs, it is determined to be abnormal attenuation. The standard deviation of the reflected signal; when Furthermore, the frequency shift changes uniformly across the entire range, satisfying... At that time, it was determined to be due to the impact of icing. for The thickness of the icing on the optical cable at all times. The standard deviation of the Brillouin frequency shift signal after calibration; When a single-point frequency shift changes abruptly And this point corresponds to the pole's anchor point, and the pole's tilt is also... At that time, it was determined that the tower structure was abnormal. For the first The tilt angle of the base tower.

10. The pole-to-optical cable positioning method based on distributed optical fiber sensing and topology matching according to claim 1, characterized in that, The formula for calculating the offset in step S7 is: ,in, for Time of the first Optical position offset of the optical cable at the base tower suspension point for The optical position of the fiber optic cable is constantly being monitored. The initial reference point for the optical cable's optical position; The formula for calculating the similarity of the hanging point feature set is as follows: ,in, To update the similarity of the feature sets of hanging points before and after, for Time of the first The feature set of the base tower hanging points For the initial feature set, The number of samples.

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