Iced optical fiber sensing and positioning method and system for optical fiber composite overhead ground wire

Abstract

The invention relates to the technical field of optical fiber sensing, in particular to an ice-coated optical fiber sensing and positioning method and system for an optical fiber composite overhead ground wire. The method comprises the following steps: connecting an optical fiber composite overhead ground wire into a Brillouin optical time domain reflectometer, and calibrating a Brillouin temperature sensitivity coefficient and a tension sensitivity coefficient; acquiring Brillouin frequency shift data; according to a Brillouin scattering principle, decoupling to obtain a Brillouin frequency shift influenced by temperature; calculating the temperature of the optical fiber composite overhead ground wire; and through comparing the temperatures of the ice area and the ice-free area, accurate positioning of the icing area is realized. The invention further provides a corresponding system which comprises a coefficient calibration module, a data acquisition module, a data decoupling module and a comparison positioning module. According to the invention, the technical bottlenecks of few monitoring points and limited coverage in the traditional monitoring technology are broken through, the whole-line-section continuous monitoring of the icing state of the power transmission line is realized, the technical problem that the common influence of temperature change and mechanical load is difficult to distinguish is solved, and the accuracy and reliability of icing area positioning are improved.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber sensing technology, and in particular to an optical fiber sensing and positioning method and system for ice-covered optical fiber composite overhead ground wires. Background Art

[0002] Overhead transmission lines are prone to ice accumulation in winter in high- and medium-altitude areas with high humidity and low temperatures. Icing can cause line tripping, tower collapse, and line breakage, resulting in prolonged and widespread power outages, significant economic losses, and severe social impacts. Therefore, accurately locating iced areas on overhead transmission lines is crucial for line operation and maintenance.

[0003] Traditionally, monitoring ice on overhead transmission lines relies primarily on manual inspections, making it difficult to accurately and timely determine the ice status of the lines, especially in mountainous areas with complex terrain and inaccessible transportation. While ice monitoring systems based on surveillance cameras and gravity sensors have been developed in recent years, these systems generally suffer from a limited number of monitoring points, limited coverage, and difficulty achieving continuous monitoring of the entire line. Due to the discrete nature of monitoring points, the ice status of the central section of the line cannot be determined, resulting in blind spots in ice monitoring and the inability to accurately locate iced areas.

[0004] With the development of fiber-optic sensing technology, distributed fiber-optic sensing based on the principle of Brillouin scattering has provided a new technical means for locating ice-covered areas. As a key component of high-voltage transmission lines, fiber-optic composite overhead ground wires not only have the lightning protection function of overhead ground wires but also integrate communication fibers for distributed temperature and strain monitoring. However, existing fiber-optic composite overhead ground wire-based ice monitoring technologies primarily focus on stress monitoring at specific points. This makes it difficult to effectively distinguish the combined effects of temperature changes and mechanical loads on the fiber's Brillouin frequency shift, limiting the accuracy and reliability of locating ice-covered areas.

[0005] To address the above problems, it is urgent to develop a distributed optical fiber sensing and positioning method for ice-covered areas of optical fiber composite overhead ground wires based on the Brillouin scattering principle, so as to accurately locate ice-covered areas of transmission lines and provide technical support for the operation and maintenance of ice-covered lines. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention is proposed.

[0007] Therefore, the problem to be solved by the present invention is how to solve the problem that traditional icing monitoring of overhead transmission lines mainly relies on manual inspections, which makes it difficult to obtain the icing status of the lines in a timely and accurate manner, especially in mountainous areas with complex terrain and inconvenient transportation. Although icing monitoring systems based on surveillance cameras, gravity sensors, etc. have been developed in recent years, these systems generally have problems such as a small number of monitoring points, limited coverage, and difficulty in achieving continuous monitoring of the entire line segment. Due to the discrete nature of the monitoring points, the icing status of the middle part of the line cannot be known, resulting in blind spots in icing monitoring and the inability to accurately locate the icing area.

[0008] With the development of fiber-optic sensing technology, distributed fiber-optic sensing based on the principle of Brillouin scattering has provided a new technical means for locating ice-covered areas. As a key component of high-voltage transmission lines, fiber-optic composite overhead ground wires not only have the lightning protection function of overhead ground wires but also integrate communication fibers for distributed temperature and strain monitoring. However, existing fiber-optic composite overhead ground wire-based ice monitoring technologies primarily focus on stress monitoring at specific points. This makes it difficult to effectively distinguish the combined effects of temperature changes and mechanical loads on the fiber's Brillouin frequency shift, limiting the accuracy and reliability of locating ice-covered areas.

[0009] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0010] In a first aspect, an embodiment of the present invention provides a method for sensing and locating iced optical fiber on an optical fiber composite overhead ground wire, comprising connecting the optical fiber composite overhead ground wire to a Brillouin optical time domain reflectometer, and calibrating the Brillouin temperature sensitivity coefficient and the Brillouin tension sensitivity coefficient of the optical fiber composite overhead ground wire;

[0011] The Brillouin frequency shift data of the optical fiber composite overhead ground wire is obtained by Brillouin optical time domain reflectometry measurement;

[0012] According to the Brillouin scattering principle, the Brillouin frequency shift data of the optical fiber composite overhead ground wire is decoupled to obtain the Brillouin frequency shift affected by temperature.

[0013] Calculate the temperature of the optical fiber composite overhead line based on the Brillouin frequency shift affected by temperature;

[0014] By comparing the calculated temperatures of the iced area of the optical fiber composite overhead ground wire with the temperatures of the ice-free area of the optical fiber composite overhead ground wire, the ice-covered area of the optical fiber composite overhead ground wire can be located.

[0015] As a preferred solution of the optical fiber sensing and positioning method for ice-covered optical fiber composite overhead ground wires described in the present invention, the Brillouin temperature sensitivity coefficient calibration step includes: obtaining ice monitoring terminal data and simulated ground wire data; collecting Brillouin frequency shift data under two different temperature states; calculating the ratio of the difference in Brillouin frequency shift under different temperature states to the temperature difference to obtain the temperature sensitivity coefficient.

[0016] As a preferred solution of the optical fiber sensing and positioning method for ice-covered optical fiber composite overhead ground wires described in the present invention, the Brillouin tension sensitivity coefficient calibration step includes: obtaining ice monitoring terminal data and simulated ground wire data; collecting Brillouin frequency shift data under different tension states; calculating the ratio of the Brillouin frequency shift difference to the tension difference to obtain the tension sensitivity coefficient.

[0017] As a preferred solution of the ice-covered optical fiber sensing and positioning method of the optical fiber composite overhead ground wire described in the present invention, the step of decoupling the Brillouin frequency shift data of the optical fiber composite overhead ground wire is achieved through the following relationship: the actual measured Brillouin frequency shift is separated from the Brillouin frequency shift component affected by temperature through the relationship with the Brillouin frequency shift in the absence of tension, the temperature sensitivity coefficient, and the tension sensitivity coefficient.

[0018] As a preferred solution of the optical fiber sensing and positioning method for ice-covered optical fiber composite overhead ground wires described in the present invention, the step of locating the ice-covered area of the optical fiber composite overhead ground wire includes: establishing a temperature threshold judgment standard; identifying the temperature characteristics of the ice-covered area and the ice-free area of the optical fiber composite overhead ground wire according to the temperature distribution of the optical fiber composite overhead ground wire; and dividing the ice-covered area and the ice-free area of the optical fiber composite overhead ground wire.

[0019] As a preferred solution of the optical fiber sensing and positioning method for ice coverage of the optical fiber composite overhead ground wire described in the present invention, the method is applied to 500kV transmission lines with a line altitude range of 1300-2480 meters, corresponding to ice coverage monitoring in different ice zones of 10-40mm.

[0020] As a preferred solution of the optical fiber sensing and positioning method for ice coverage of the optical fiber composite overhead ground wire described in the present invention, the method further includes: constructing an icing risk level assessment model; based on the positioning results of the ice coverage area of the optical fiber composite overhead ground wire, performing a graded assessment of the line icing risk; and formulating corresponding operation and maintenance strategies and anti-icing and ice-melting measures according to different levels of icing risk.

[0021] In a second aspect, an embodiment of the present invention provides an ice-covered optical fiber sensing and positioning system for an optical fiber composite overhead ground wire, which includes a coefficient calibration module, which connects the optical fiber composite overhead ground wire to a Brillouin optical time domain reflectometer to calibrate the Brillouin temperature sensitivity coefficient and the Brillouin tension sensitivity coefficient of the optical fiber composite overhead ground wire;

[0022] The data acquisition module measures and obtains the Brillouin frequency shift data of the optical fiber composite overhead ground wire through Brillouin optical time domain reflectometry;

[0023] The data decoupling module decouples the Brillouin frequency shift data of the optical fiber composite overhead ground line based on the Brillouin scattering principle to obtain the Brillouin frequency shift affected by temperature. Based on the Brillouin frequency shift affected by temperature, the temperature of the optical fiber composite overhead ground line is calculated.

[0024] The comparison and positioning module locates the ice-covered area of the optical fiber composite overhead ground wire by comparing the calculated temperature of the ice-covered area of the optical fiber composite overhead ground wire with the temperature of the ice-free area of the optical fiber composite overhead ground wire.

[0025] In a third aspect, an embodiment of the present invention provides a computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program instructions are executed by the processor, the steps of the ice-covered optical fiber sensing and positioning method for the optical fiber composite overhead ground wire as described in the first aspect of the present invention are implemented.

[0026] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program instructions are executed by a processor, the steps of the ice-covered optical fiber sensing and positioning method for the optical fiber composite overhead ground wire as described in the first aspect of the present invention are implemented.

[0027] The present invention provides significant advantages for detecting ice on fiber-optic composite overhead ground wires. By connecting the fiber-optic composite overhead ground wire to a Brillouin optical time-domain reflectometer and calibrating its temperature and tension sensitivity coefficients, a precise parameter foundation is established, effectively overcoming the sensitivity coefficient errors encountered in traditional monitoring. This method enables distributed, real-time monitoring of the entire transmission line, overcoming the technical bottleneck of traditional monitoring systems, which suffer from a limited number of monitoring points and coverage, and eliminating monitoring blind spots.

[0028] An innovative Brillouin frequency shift decoupling model was established, successfully separating the temperature-related frequency shift component and resolving the technical challenge of distinguishing the combined effects of temperature change and mechanical load. Combined with multi-level ice-covered area positioning technology, precise identification of ice-covered areas was achieved, significantly improving positioning accuracy. The constructed risk level assessment model established a complete technical chain from monitoring, assessment, and response, significantly reducing the safety risks caused by line icing.

[0029] This method is suitable for high-voltage transmission lines in complex terrain, especially long-span transmission lines in high-altitude areas, and is highly practical and adaptable. It fully utilizes existing fiber-optic composite overhead ground wire resources, eliminates the need for additional independent sensing equipment, and offers high system integration, low installation and maintenance costs, and achieves "zero-increment" real-time monitoring, offering significant economic and technical advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 A flow chart of an optical fiber sensing and positioning method for ice-covered optical fiber composite overhead ground wires;

[0032] Figure 2 A diagram of computer equipment for an optical fiber sensing and positioning method for ice coating on optical fiber composite overhead ground wires;

[0033] Figure 3 A schematic diagram of line measurement for an optical fiber sensing and positioning method for ice coverage on optical fiber composite overhead ground wires;

[0034] Figure 4 Brillouin frequency shift diagram of the ice-covered optical fiber sensing positioning method for optical fiber composite overhead ground wire;

[0035] Figure 5 This is a calibration diagram of the Brillouin temperature sensitivity coefficient of the ice-covered optical fiber sensing positioning method for optical fiber composite overhead ground wires;

[0036] Figure 6 This is the calibration diagram of the Brillouin tension sensitivity coefficient of the ice-covered optical fiber sensing positioning method for optical fiber composite overhead ground wires. DETAILED DESCRIPTION

[0037] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0038] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0039] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it constitute a separate or selective embodiment that is mutually exclusive with other embodiments.

[0040] Example 1

[0041] Reference Figures 1 to 6, which is the first embodiment of the present invention, provides an ice-covered optical fiber sensing and positioning method for an optical fiber composite overhead ground wire, comprising:

[0042] S100: Connect the optical fiber composite overhead ground wire to the Brillouin optical time domain reflectometer to calibrate the Brillouin temperature sensitivity coefficient and Brillouin tension sensitivity coefficient of the optical fiber composite overhead ground wire;

[0043] In the embodiment of the present application, it is first necessary to determine the basic parameters of the optical fiber composite overhead ground wire. Taking the 500kV Sashe line as an example, this line starts from the 500kV Wusa substation and ends at the 500kV Shexiang substation, with a total length of 169.318km and a total of 469 towers. The line runs from the 500kV Wusa substation through Weining Yi, Hui and Miao Autonomous County, Hezhang County, Shuicheng County, Nayong County, and Dafang County in Guizhou Province. Most of the areas through which the line passes are high mountains and ridges, accompanied by a small amount of general mountains and hills. The entire line has an altitude of 1,300-2,480 meters. Among them, high mountains and ridges account for 48%, general mountains account for 36%, and hills account for 16%.

[0044] According to the distribution of ice zones along the 500kV Sashe line, the entire line is in the 10mm-40mm ice zone, specifically as follows: 10mm ice zone (tower section 426-435, 3.871km long); 15mm ice zone (tower sections 267-311, 361-385, 395-426, 435-469, 57.579km long); 20mm ice zone (tower sections 237-267, 311-361, 385-395, 34.545km long); 30mm ice zone (tower sections 001-040, 093-119, 165-237, 43.607km long); and 40mm ice zone (tower sections 040-093, 119-165, 29.716km long).

[0045] The selection of fiber-optic composite overhead ground wires depends on the ice zone conditions: JLB35-150 is used for the outlet of the luxury incense transformer, JLB20A-120 is used for ice zones of 20mm and below, JLB20A-150 is used for ice zones of 30mm, and JLB20A-185 is used for ice zones of 40mm. The corresponding optical cable configuration is: OPGW-155 is used for the outlet of the luxury incense transformer, OPGW-155-120 is used for ice zones of 20mm and below, OPGW-155-150 is used for ice zones of 30mm, and OPGW-155-185 is used for ice zones of 40mm.

[0046] In this embodiment, the Brillouin optical time-domain reflectometry (OTDR) operates based on the Brillouin scattering effect. When a light pulse passes through an optical fiber, phonons in the fiber interact with the incident light, generating scattered light with a frequency shift. This scattering is known as Brillouin scattering. The frequency shift of the Brillouin scattered light (i.e., the Brillouin frequency shift) is directly related to the temperature and strain state of the optical fiber. Therefore, by measuring the Brillouin frequency shift, both the temperature and strain information of the optical fiber can be simultaneously obtained.

[0047] When connecting a fiber-optic composite overhead ground wire to a Brillouin optical time-domain reflectometer, you first need to set up the connection. The specific steps include:

[0048] Connecting the optical fiber in the optical fiber composite overhead ground wire to the optical fiber interface of the Brillouin optical time domain reflectometer;

[0049] Set the measurement parameters of the Brillouin optical time-domain reflectometer, including spatial resolution, sampling interval, and averaging times;

[0050] Calibrate the zero point position of the Brillouin optical time domain reflectometer;

[0051] Set the wavelength range and scan step size for measurement.

[0052] The calibration of the Brillouin temperature sensitivity coefficient and the Brillouin tension sensitivity coefficient is mainly achieved through the following steps:

[0053] Brillouin temperature sensitivity coefficient calibration: obtain ice cover monitoring terminal data and simulated ground line data; collect Brillouin frequency shift data under two different temperature conditions; calculate the ratio of the difference in Brillouin frequency shift under different temperature conditions to the temperature difference to obtain the temperature sensitivity coefficient.

[0054] The calculation formula of Brillouin temperature sensitivity coefficient is:

[0055]

[0056] Among them, ν1 and ν2 are the Brillouin frequency shifts under two different temperature states, T1 and T2 are the temperatures of the optical fiber composite overhead ground wire under two states, C νT is the temperature sensitivity coefficient.

[0057] Brillouin tension sensitivity coefficient calibration: obtain ice monitoring terminal data and simulated ground wire data; collect Brillouin frequency shift data under different tension states; calculate the ratio of the Brillouin frequency shift difference to the tension difference to obtain the tension sensitivity coefficient.

[0058] The calculation formula of Brillouin tension sensitivity coefficient is:

[0059]

[0060] Where Δν is the difference in Brillouin frequency shift under two different tension states, CνF is the tension sensitivity coefficient, and ΔF is the tension difference of the optical fiber composite overhead ground wire under two conditions.

[0061] During the calibration process, a temperature control chamber and a tensile testing platform are used for precise control to ensure calibration accuracy. The temperature control chamber can maintain a temperature range of -30°C to +80°C with an accuracy of ±0.1°C; the tensile testing platform can apply a tensile force of 0-20kN with an accuracy of ±0.5%. By varying the temperature and tensile force and recording the corresponding Brillouin frequency shift, the temperature sensitivity coefficient and the tension sensitivity coefficient are obtained.

[0062] In the actual implementation process, we selected several representative points along the line for calibration, such as:

[0063] Optical fiber composite overhead ground wire in low altitude areas (about 1300m)

[0064] Fiber-optic composite overhead ground wire in medium altitude areas (about 1800m)

[0065] Optical fiber composite overhead ground wire in high altitude areas (about 2400m)

[0066] In this way, the temperature sensitivity coefficient and tension sensitivity coefficient at different altitudes can be obtained, providing a more accurate reference for subsequent monitoring.

[0067] S101: The Brillouin temperature sensitivity coefficient calibration step includes: obtaining ice monitoring terminal data and simulated ground line data; collecting Brillouin frequency shift data under two different temperature conditions; calculating the ratio of the difference in Brillouin frequency shift under different temperature conditions to the temperature difference to obtain the temperature sensitivity coefficient.

[0068] In this step, a Brillouin optical time-domain reflectometer is used to perform real-time measurements on the connected fiber-optic composite overhead ground wire to obtain Brillouin frequency shift data along the line. The specific measurement method is as follows:

[0069] Set the measurement parameters of the Brillouin optical time-domain reflectometer:

[0070] Spatial resolution: usually set to 2-5 meters, depending on the monitoring accuracy requirements; measurement range: 0-170km, covering the entire line; number of scans: set to 10-20 times, and take the average value to improve measurement accuracy; measurement time interval: can be set to 5-15 minutes, adjusted according to actual needs.

[0071] Start the measurement program to obtain Brillouin scattering data of the fiber-optic composite overhead ground wire.

[0072] Data preprocessing: Filter the raw data to remove noise interference; perform data smoothing to improve signal quality; identify and mark abnormal data points.

[0073] Extract Brillouin frequency shift information:

[0074] Analyze the Brillouin scattering spectrum of each measurement point; determine the peak position of the Brillouin frequency shift; and record the Brillouin frequency shift value at each point.

[0075] Data storage and transmission:

[0076] The acquired Brillouin frequency shift data is stored in a local database; the data is transmitted to a central monitoring system via a communication network; and the security and integrity of the data are ensured.

[0077] In the actual measurement process, according to the actual situation of the 500kV transmission line, the following strategies can be selected:

[0078] For areas with more severe ice (30mm-40mm ice area), the measurement frequency can be increased and set to once every 5 minutes; for areas with less ice (10mm-20mm ice area), the measurement frequency can be reduced and set to once every 15 minutes; under special weather conditions (such as low temperature, rain and snow), the measurement frequency can be temporarily increased to improve monitoring accuracy.

[0079] Brillouin optical time-domain reflectometry (OTDR) works by emitting a light pulse and detecting the Brillouin scattered light generated as it propagates along an optical fiber. By analyzing the frequency shift characteristics of the scattered light, temperature and strain information can be obtained at various points on the fiber. In practice, OTDR can perform distributed measurements on optical fibers up to tens of kilometers long, with accuracies reaching 1°C and 20με, and spatial resolutions up to 1 meter.

[0080] Furthermore, to improve measurement accuracy, differential boolean optical time-domain analysis (D-BOTDA) can be used to eliminate the cumulative errors associated with single-ended measurements through dual-end measurement. On the 500kV Sa-She line, simultaneous measurements can be performed at both the Wusa and Shexiang substations, with data fusion algorithms used to improve monitoring accuracy.

[0081] S200: Obtain Brillouin frequency shift data of optical fiber composite overhead ground wire through Brillouin optical time domain reflectometry measurement;

[0082] S201: The Brillouin tension sensitivity coefficient calibration step includes: obtaining ice monitoring terminal data and simulated ground wire data; collecting Brillouin frequency shift data under different tension states; calculating the ratio of the Brillouin frequency shift difference to the tension difference to obtain the tension sensitivity coefficient.

[0083] S300: Based on the Brillouin scattering principle, the Brillouin frequency shift data of the optical fiber composite overhead ground wire is decoupled to obtain the Brillouin frequency shift affected by temperature.

[0084] S301: The step of decoupling the Brillouin frequency shift data of the optical fiber composite overhead ground wire is achieved by the following relationship: the Brillouin frequency shift actually measured is separated from the Brillouin frequency shift component affected by temperature by the relationship between the Brillouin frequency shift without tension, the temperature sensitivity coefficient, and the tension sensitivity coefficient.

[0085] After obtaining the Brillouin frequency shift data, it is necessary to decouple the Brillouin frequency shift component affected by temperature. This is because the Brillouin frequency shift is affected by both temperature and tension (strain), and these two effects need to be separated.

[0086] The decoupling process is based on the following fundamental relationship from the Brillouin scattering principle:

[0087] ν=ν0+C νT T+C νF F

[0088] Where ν is the actual measured Brillouin frequency shift, ν0 is the Brillouin frequency shift when there is no tension, and C νT T is the temperature sensitivity coefficient, T is the temperature, C νF F is the tension sensitivity coefficient, and F is the tension.

[0089] The decoupling steps are as follows:

[0090] Get the calibrated temperature sensitivity coefficient C νT T and tension sensitivity coefficient C νF F;

[0091] Measure the actual Brillouin frequency shift ν of the optical fiber composite overhead ground wire;

[0092] Get the initial Brillouin frequency shift ν0 (usually a reference value measured during manufacturing and installation)

[0093] The Brillouin frequency shift component affected by temperature and the Brillouin frequency shift component affected by tension are decoupled.

[0094] The specific decoupling method can be achieved in the following ways:

[0095] Method 1: Decoupling method based on temperature reference point

[0096] This method utilizes specific reference points along the line. The temperatures at these points can be directly measured using other temperature sensors (such as thermocouples and thermistors). This allows the relationship between the Brillouin frequency shift and temperature at these points to be determined. Using this information from these reference points, the temperature distribution along the entire line can be estimated, further isolating the effects of tension.

[0097] On the 500kV Sashe line, temperature sensors can be installed at tower locations, such as towers 001, 093, 165, 237, 311, 361, 395, 426 and 469, covering different ice zones and altitudes.

[0098] Method 2: Homogeneous fiber decoupling method

[0099] Two identical optical fibers, one strain-affected and the other unaffected, are laid in a fiber-optic composite overhead ground wire. Since the two fibers are exposed to the same temperature, the effects of temperature and strain can be separated by comparing their Brillouin frequency shifts.

[0100] In the fiber-optic composite overhead ground wire of the 500kV Sashe line, a free optical fiber (not affected by tension) and a fastened optical fiber (affected by tension) can be arranged. The former only reflects temperature changes, while the latter reflects both temperature and tension changes. By comparing the Brillouin frequency shifts of the two, the effects of temperature and tension can be decoupled.

[0101] Method 3: Mathematical model decoupling method

[0102] By establishing the mechanical model and thermodynamic model of the optical fiber composite overhead ground wire, combining the geometric parameters, material properties and external environmental conditions of the line, a set of equations for the relationship between Brillouin frequency shift and temperature and tension is constructed, and decoupling is achieved by solving the set of equations.

[0103] For the 500kV Sashe line, a mechanical model can be established based on its basic parameters. Considering the line's altitude of 1,300 to 2,480 meters and the complex terrain of each section, the line can be divided into several typical sections and models can be developed for each. For example, the line can be divided into five sections based on ice depth (10mm, 15mm, 20mm, 30mm, and 40mm ice zones), and a corresponding mechanical model can be constructed for each section.

[0104] In actual operation, we use method 3 for decoupling and calibrate the temperature reference point in method 1. The decoupling steps are as follows:

[0105] Collect basic line parameters: tower coordinates, conductor parameters, span, altitude, etc.

[0106] Establish a mechanical model of the line and calculate the line tension under different temperature and ice load conditions based on the line's geometry and material properties

[0107] Use the temperature sensor data installed on the line as a reference to calibrate the model parameters

[0108] The Brillouin frequency shift affected by temperature is calculated according to the decoupling formula:

[0109] Δ νT=v-ν0-C νF F

[0110] Wherein, F is the tension of the optical fiber composite overhead ground wire calculated by the mechanical model.

[0111] S400: Calculate the temperature of the optical fiber composite overhead line based on the Brillouin frequency shift affected by temperature;

[0112] After obtaining the Brillouin frequency shift affected by temperature, the temperature at each point of the fiber-optic composite overhead ground wire can be calculated using the previously calibrated temperature sensitivity coefficient. The calculation formula is as follows:

[0113]

[0114] Where T is the temperature of the optical fiber composite overhead ground wire, Δ νT is the Brillouin frequency shift affected by temperature, C νT is the temperature sensitivity coefficient.

[0115] In order to improve the accuracy of temperature calculation, the following factors need to be considered:

[0116] Nonlinearity of temperature sensitivity coefficient: In extreme temperature environments, the temperature sensitivity coefficient may exhibit nonlinear characteristics. Therefore, during the calculation process, a piecewise linear or polynomial fitting method can be used to select the appropriate temperature sensitivity coefficient according to different temperature ranges.

[0117] Optimizing spatial resolution: Brillouin scattering signals have a certain spatial broadening effect, which affects the spatial resolution of the measurement. By adopting pulse coding technology or differential Brillouin optical time-domain analysis technology, the spatial resolution can be improved and more detailed temperature distribution information can be obtained.

[0118] Signal Noise Processing: The Brillouin scattering signal in actual measurements may contain noise, which can affect the accuracy of temperature calculations. Signal filtering and averaging multiple measurements can reduce the impact of noise and improve the reliability of temperature calculations.

[0119] Correction of systematic errors: The system may have inherent errors. By comparing and calibrating with a reference temperature sensor, the systematic errors can be eliminated and the accuracy of temperature calculation can be improved.

[0120] According to the actual situation of 500kV Sashe line, we can adopt the following temperature calculation strategy:

[0121] According to the distribution of ice areas on the line, different temperature calculation parameters are used for different ice sections:

[0122] 10mm ice area (tower section 426-435): standard temperature sensitivity coefficient is used

[0123] 15mm ice area (tower sections 267-311, 361-385, 395-426, and 435-469): adjust the temperature sensitivity coefficient to take altitude into account;

[0124] 20mm ice area (tower sections 237-267, 311-361, and 385-395): adjust the temperature sensitivity coefficient considering the influence of micro-topography;

[0125] 30mm ice area (tower sections 001-040, 093-119, and 165-237): adjust the temperature sensitivity coefficient considering the influence of wind speed;

[0126] 40mm ice area (tower sections 040-093 and 119-165): a nonlinear temperature sensitivity coefficient model is used.

[0127] For special sections, such as large span sections and sections with drastic terrain changes, a refined temperature calculation model is used to improve calculation accuracy.

[0128] Use weather station data as auxiliary information to improve the reliability of temperature calculations. For example, use temperature data from weather stations along the line as a reference to correct the temperature calculation results of the fiber-optic composite overhead ground wire.

[0129] After completing the temperature calculation, a temperature distribution map of the entire fiber-optic composite overhead ground wire can be obtained. This map uses distance as the horizontal axis and temperature as the vertical axis to intuitively display the temperature status at each point on the line. For the 500kV Sashe line, this temperature distribution map clearly identifies the temperature characteristics of different altitudes and different ice zones, providing basic data for subsequent ice-covered area location.

[0130] S500: Positioning the ice-covered area of the optical fiber composite overhead ground wire is achieved by comparing the calculated temperature of the ice-covered area of the optical fiber composite overhead ground wire with the temperature of the ice-free area of the optical fiber composite overhead ground wire.

[0131] S501: The steps of locating the iced area of the optical fiber composite overhead ground wire include: establishing a temperature threshold judgment standard; identifying the temperature characteristics of the iced area and the non-iced area of the optical fiber composite overhead ground wire according to the temperature distribution of the optical fiber composite overhead ground wire; and dividing the iced area and the non-iced area of the optical fiber composite overhead ground wire.

[0132] S502: The method is applied to 500kV transmission lines with line altitudes between 1300 and 2480 meters above sea level, corresponding to ice coverage monitoring in different ice zones ranging from 10 to 40 mm.

[0133] In this step, the temperature characteristics of each point on the fiber-optic composite overhead ground wire are compared to accurately locate the ice-covered area. There are significant differences in the temperature characteristics of ice-covered areas and ice-free areas, which are mainly manifested in the following aspects:

[0134] Absolute temperature difference: The temperature of the optical fiber composite overhead ground wire in the ice-covered area is usually lower than that in the ice-free area, especially in the early stage of ice formation and during the melting process. The temperature in the ice-covered area is usually close to or slightly below 0°C.

[0135] Difference in temperature change rate: The temperature change rate in ice-covered areas is usually lower than that in ice-free areas. This is because the presence of ice increases the heat capacity of the line, slowing its response to ambient temperature changes.

[0136] Daily temperature difference characteristics: The daily temperature difference in ice-covered areas is usually smaller than that in ice-free areas. The insulating effect of the ice layer reduces the temperature variation of the line.

[0137] Temperature gradient characteristics: There is usually a significant temperature gradient between ice-covered areas and ice-free areas. This gradient can serve as an important basis for identifying ice-covered boundaries.

[0138] Based on the above temperature characteristic differences, we can use the following methods to locate the ice-covered area:

[0139] Method 1: Temperature threshold method

[0140] Set a temperature threshold and identify areas with temperatures below the threshold as ice-covered areas. This method is simple and intuitive, but the threshold must be dynamically adjusted based on the current ambient temperature.

[0141] For the 500kV Sashe line, considering the large altitude span of the line (1300-2480 meters), the temperature thresholds at different altitudes should be different:

[0142] Low altitude areas (1300-1600 meters): the temperature threshold is set to -1°C;

[0143] Medium altitude areas (1600-2000 meters): the temperature threshold is set to -2°C;

[0144] High altitude areas (2000-2480 meters): The temperature threshold is set to -3℃.

[0145] Method 2: Temperature change rate method

[0146] Analyze the temperature change rate of the fiber-optic composite overhead ground wire. Areas with low temperature change rates may be ice-covered areas. Icing areas can be identified by calculating the temperature change rate over consecutive time periods and combining it with ambient temperature changes.

[0147] For the 500kV Sashe line, the following rate of change thresholds can be set:

[0148] When the ambient temperature change rate is α°C / hour, if the temperature change rate of the optical fiber composite overhead ground wire is less than 0.5α°C / hour, it is considered that there may be ice covering in the area.

[0149] Method 3: Temperature feature pattern recognition method

[0150] Based on historical data, a library of temperature characteristic patterns for ice-covered and ice-free areas is established, and current ice-covered areas are identified through pattern matching. This method considers the combined influence of multiple temperature characteristics and has high positioning accuracy, but it requires extensive historical data support.

[0151] In practical applications, we use a combination of the above three methods to improve positioning accuracy:

[0152] First, the temperature threshold method is used for preliminary screening to identify possible ice-covered areas; then, the temperature change rate method is used for further verification to remove misjudged areas; finally, the temperature feature pattern recognition method is used for fine positioning to determine the exact range of the ice-covered area.

[0153] For the 500kV Sashe line, the ice-covered area can be located by following the steps below:

[0154] The line is divided into sections according to the tower numbers, with every 10 towers forming a basic unit. The above positioning method is applied to each unit. For sections with high ice levels (30mm and 40mm ice zones), the monitoring points are increased to improve positioning accuracy. The positioning results are optimized by combining the micro-topographic features of the line (ridges, valleys, river crossings, etc.). Meteorological data (temperature, humidity, wind speed, etc.) are used to assist in judgment and improve positioning reliability. The actual icing conditions are verified and corrected through monitoring images or feedback from line patrol personnel.

[0155] To improve the accuracy of ice-covered area positioning, the system can also establish an ice risk assessment model that comprehensively considers the following factors:

[0156] Historical icing frequency: Based on historical data, the icing frequency of each section of the line is statistically analyzed. Areas with high frequencies have a higher risk of icing. Topographic factors: The icing risk is higher in special terrain areas such as valleys, ridges, and river crossings. Meteorological conditions: The icing risk is higher under low temperature, high humidity, and precipitation. Line characteristics: The icing risk is higher in special structures such as large spans and corner towers.

[0157] Through comprehensive analysis of these factors, the system can give the icing risk level of each section of the line, providing decision-making reference for operation and maintenance personnel.

[0158] Based on the location of iced areas, the severity of ice can be further estimated. Generally speaking, the lower the temperature in the iced area, the more severe the ice. By analyzing the detailed characteristics of the temperature distribution, it is possible to estimate areas with light, moderate, and heavy ice coverage, providing targeted guidance for subsequent ice prevention and melting operations.

[0159] Furthermore, the results of ice-covered area positioning should be dynamically updated. As weather conditions and line status change, the ice-covered area should be regularly recalculated and updated. During severe weather, the update cycle can be shortened, improving the real-time nature of monitoring.

[0160] Through the above technical solution, the precise positioning of the ice-covered area of the 500kV Sashe line optical fiber composite overhead ground wire was achieved, providing important support for the safe operation of the line and anti-icing and ice-melting work.

[0161] S503: Also includes: constructing an icing risk level assessment model; conducting a graded assessment of the line icing risk based on the results of locating the icing area of the optical fiber composite overhead ground wire; and formulating corresponding operation and maintenance strategies and anti-icing and ice-melting measures according to different levels of icing risk.

[0162] After locating the iced areas of fiber-optic composite overhead ground wires, we can further construct an icing risk assessment model to assess the icing risk of the lines at different levels. This model comprehensively considers multiple factors to achieve a more scientific and accurate risk assessment.

[0163] The steps for constructing the icing risk level assessment model are as follows:

[0164] Determine the assessment factors: Select key factors that have a significant impact on icing risk, including:

[0165] Temperature factors: real-time temperature of the fiber-optic composite overhead ground wire and its changing trend; meteorological factors: ambient temperature, humidity, wind speed, precipitation, etc.; geographical factors: altitude, terrain features (valleys, ridges, river crossings, etc.); historical factors: historical icing frequency, severity, duration, etc.; line factors: line structure, span length, tower type, etc.

[0166] Establish a factor weight system: Use the analytic hierarchy process (AHP) or entropy weight method to determine the weight of each factor to reflect the impact of each factor on icing risk.

[0167] For the 500kV Sashe line, based on the line characteristics and historical operating experience, the following weights can be set: temperature factor weight: 0.35; meteorological factor weight: 0.25; geographical factor weight: 0.20; historical factor weight: 0.15; line factor weight: 0.05.

[0168] Establish scoring criteria: Set quantitative scoring criteria for each factor, converting qualitative descriptions into quantitative indicators. Taking the temperature factor as an example, the following scoring criteria can be set: 0-2°C: 5 points (high risk); -5-0°C: 4 points (relatively high risk); -10--5°C: 3 points (medium risk); -15--10°C: 2 points (low risk); <-15°C or >2°C: 1 point (low risk).

[0169] Assessment model construction: The weighted comprehensive scoring method is used to construct an icing risk assessment model and calculate the icing risk index of each line segment.

[0170] Icing risk index calculation formula:

[0171]

[0172] Where R is the ice risk index, w i is the weight of the i-th factor, s i is the score of the ith factor, and n is the total number of factors.

[0173] Risk level classification: According to the icing risk index, the lines are divided into different risk levels, such as low risk, medium-low risk, medium risk, medium-high risk and high risk.

[0174] Icing risk level classification standards:

[0175] Risk index <1.5: low risk (Level I); 1.5≤Risk index <2.5: medium-low risk (Level II); 2.5≤Risk index <3.5: medium risk (Level III); 3.5≤Risk index <4.5: medium-high risk (Level IV); Risk index ≥4.5: high risk (Level V).

[0176] Furthermore, this embodiment also provides an ice-covered optical fiber sensing and positioning system for optical fiber composite overhead ground wires, comprising:

[0177] The coefficient calibration module connects the optical fiber composite overhead ground wire to the Brillouin optical time domain reflectometer to calibrate the Brillouin temperature sensitivity coefficient and Brillouin tension sensitivity coefficient of the optical fiber composite overhead ground wire;

[0178] The data acquisition module measures and obtains the Brillouin frequency shift data of the optical fiber composite overhead ground wire through Brillouin optical time domain reflectometry;

[0179] The data decoupling module decouples the Brillouin frequency shift data of the optical fiber composite overhead ground line based on the Brillouin scattering principle to obtain the Brillouin frequency shift affected by temperature. Based on the Brillouin frequency shift affected by temperature, the temperature of the optical fiber composite overhead ground line is calculated.

[0180] The comparison and positioning module locates the ice-covered area of the optical fiber composite overhead ground wire by comparing the calculated temperature of the ice-covered area of the optical fiber composite overhead ground wire with the temperature of the ice-free area of the optical fiber composite overhead ground wire.

[0181] In summary, by connecting the fiber-optic composite overhead ground wire to the Brillouin optical time-domain reflectometer and calibrating the temperature sensitivity coefficient and tension sensitivity coefficient, a quantitative relationship between the Brillouin frequency shift and temperature and tension was established, providing a scientific and accurate parameter basis for subsequent data decoupling temperature calculation, thereby overcoming the monitoring error problem caused by inaccurate sensitivity coefficients in traditional monitoring methods.

[0182] By obtaining the Brillouin frequency shift data of the fiber-optic composite overhead ground wire through the Brillouin optical time-domain reflectometer, distributed real-time monitoring of the entire transmission line is achieved. This breaks through the technical bottleneck of the traditional monitoring method with few points and limited coverage, eliminates monitoring blind spots, and improves the spatial continuity and integrity of ice cover monitoring.

[0183] By establishing a decoupling model of Brillouin frequency shift from temperature and tension, the Brillouin frequency shift component affected by temperature was successfully separated, solving the technical problem of traditional technology that it is difficult to effectively distinguish the combined effects of temperature changes and mechanical loads on the Brillouin frequency shift of optical fibers, and significantly improving the accuracy of temperature monitoring.

[0184] The temperature of the optical fiber composite overhead line is calculated based on the Brillouin frequency shift affected by temperature. By innovatively considering differentiated temperature calculation strategies at different altitudes and in different ice zones, the problem of inaccurate temperature calculation under complex terrain conditions is solved, making temperature monitoring more in line with the actual situation of the line.

[0185] By comparing the temperature characteristic differences between ice-covered areas and ice-free areas and combining the multi-level ice-covered area positioning technology of temperature threshold method, temperature change rate method and temperature characteristic pattern recognition method, accurate identification and positioning of ice-covered areas are achieved, which greatly improves the accuracy of ice-covered area positioning and provides accurate regional information for the anti-icing and ice-melting work of transmission lines.

[0186] By constructing an icing risk level assessment model, the line icing risk is assessed in a graded manner, and corresponding operation and maintenance strategies and anti-icing and ice-melting measures are formulated according to different levels of icing risk. A complete technical chain from monitoring, assessment to response has been established, which has improved the scientific nature and pertinence of power grid operation and maintenance, and significantly reduced the safety risks such as tripping, tower collapse, and line breakage caused by line icing.

[0187] This method is particularly suitable for high-voltage transmission lines under complex terrain conditions, especially 500kV transmission lines with line altitudes between 1300-2480 meters. It corresponds to ice coverage monitoring in different ice zones of 10-40mm. It has strong practicality and adaptability, and can meet the needs of ice coverage monitoring for transmission lines in areas with large differences in terrain and meteorological environments.

[0188] This method fully utilizes the existing fiber-optic composite overhead ground wire resources, does not require additional independent sensing equipment, has high system integration, low installation and maintenance costs, and realizes "zero-increment" real-time monitoring of the icing status of transmission lines, with significant economic and technical advantages.

[0189] Example 2

[0190] This embodiment also provides a computer device, which is suitable for a method for optical fiber sensing and positioning of ice-covered optical fiber composite overhead ground wires, including a memory and a processor; the memory is used to store computer-executable instructions, and the processor is used to execute computer-executable instructions to implement a forced oscillation detection and positioning method for distribution networks proposed in the above embodiment.

[0191] This embodiment further provides a storage medium storing a computer program, which, when executed by a processor, implements a forced oscillation detection and positioning method for a distribution network as proposed in the above embodiment.

[0192] The computer device may be a terminal, comprising a processor, a memory, a communication interface, a display screen and an input device connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device comprises a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner may be achieved through Wi-Fi, an operator network, NFC (near field communication) or other technologies. The display screen of the computer device may be a liquid crystal display or an electronic ink display screen, and the input device of the computer device may be a touch layer covering the display screen, or a button, trackball or touchpad provided on the housing of the computer device, or an external keyboard, touchpad or mouse.

[0193] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the various embodiments of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, and other media that can store program code.

[0194] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0195] More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic devices), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0196] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0197] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for sensing and locating iced optical fiber on an optical fiber composite overhead ground wire, characterized by: include, Connect the fiber-optic composite overhead ground wire to the Brillouin optical time-domain reflectometer to calibrate the Brillouin temperature sensitivity coefficient and Brillouin tension sensitivity coefficient of the fiber-optic composite overhead ground wire; The Brillouin frequency shift data of the optical fiber composite overhead ground wire is obtained by Brillouin optical time domain reflectometry measurement; According to the Brillouin scattering principle, the Brillouin frequency shift data of the optical fiber composite overhead ground wire is decoupled to obtain the Brillouin frequency shift affected by temperature. Calculate the temperature of the optical fiber composite overhead line based on the Brillouin frequency shift affected by temperature; By comparing the calculated temperatures of the iced area of the optical fiber composite overhead ground wire with the temperatures of the ice-free area of the optical fiber composite overhead ground wire, the ice-covered area of the optical fiber composite overhead ground wire can be located.

2. The ice-covered optical fiber sensing and positioning method for an optical fiber composite overhead ground wire according to claim 1, characterized in that: The Brillouin temperature sensitivity coefficient calibration step includes: obtaining ice monitoring terminal data and simulated ground line data; collecting Brillouin frequency shift data under two different temperature states; calculating the ratio of the difference in Brillouin frequency shift under different temperature states to the temperature difference to obtain the temperature sensitivity coefficient.

3. The ice-covered optical fiber sensing and positioning method for an optical fiber composite overhead ground wire according to claim 2, characterized in that: The Brillouin tension sensitivity coefficient calibration step includes: obtaining ice monitoring terminal data and simulated ground wire data; collecting Brillouin frequency shift data under different tension states; and calculating the ratio of the Brillouin frequency shift difference to the tension difference to obtain the tension sensitivity coefficient.

4. The ice-covered optical fiber sensing and positioning method for an optical fiber composite overhead ground wire according to claim 3, characterized in that: The step of decoupling the Brillouin frequency shift data of the optical fiber composite overhead ground wire is achieved through the following relationship: the Brillouin frequency shift actually measured is separated from the Brillouin frequency shift component affected by temperature by the relationship between the Brillouin frequency shift without tension, the temperature sensitivity coefficient, and the tension sensitivity coefficient.

5. The ice-covered optical fiber sensing and positioning method for an optical fiber composite overhead ground wire according to claim 4, characterized in that: The steps of locating the ice-covered area of the optical fiber composite overhead ground wire include: establishing a temperature threshold judgment standard; identifying the temperature characteristics of the ice-covered area and the non-ice-covered area of the optical fiber composite overhead ground wire according to the temperature distribution of the optical fiber composite overhead ground wire; and dividing the ice-covered area and the non-ice-covered area of the optical fiber composite overhead ground wire.

6. The ice-covered optical fiber sensing and positioning method for an optical fiber composite overhead ground wire according to claim 5, characterized in that: It also includes 500kV transmission lines applied to line altitudes between 1300 and 2480 meters, corresponding to ice coverage monitoring in different ice zones of 10-40mm.

7. The ice-covered optical fiber sensing and positioning method for an optical fiber composite overhead ground wire according to claim 6, characterized in that: The method further includes: constructing an icing risk level assessment model; performing a graded assessment of line icing risks based on the results of locating the icing areas of the optical fiber composite overhead ground wire; and formulating corresponding operation and maintenance strategies and anti-icing and ice-melting measures according to different levels of icing risks.

8. An optical fiber sensing and positioning system for ice-covered optical fiber composite overhead ground wires, based on the optical fiber sensing and positioning method for ice-covered optical fiber composite overhead ground wires according to any one of claims 1 to 7, characterized in that: The invention also includes a coefficient calibration module, which connects the optical fiber composite overhead ground wire to the Brillouin optical time domain reflectometer to calibrate the Brillouin temperature sensitivity coefficient and the Brillouin tension sensitivity coefficient of the optical fiber composite overhead ground wire; The data acquisition module measures and obtains the Brillouin frequency shift data of the optical fiber composite overhead ground wire through Brillouin optical time domain reflectometry; The data decoupling module decouples the Brillouin frequency shift data of the optical fiber composite overhead ground line based on the Brillouin scattering principle to obtain the Brillouin frequency shift affected by temperature. Based on the Brillouin frequency shift affected by temperature, the temperature of the optical fiber composite overhead ground line is calculated. The comparison and positioning module locates the ice-covered area of the optical fiber composite overhead ground wire by comparing the calculated temperature of the ice-covered area of the optical fiber composite overhead ground wire with the temperature of the ice-free area of the optical fiber composite overhead ground wire.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the ice-covered optical fiber sensing and positioning method for optical fiber composite overhead ground wires according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the ice-covered optical fiber sensing and positioning method for an optical fiber composite overhead ground wire according to any one of claims 1 to 7 are implemented.

Images