Multi-stranded optical fiber composite carbon fiber core temperature and strain decoupling method, system and device based on multi-channel BOTDR, and storage medium

Abstract

The invention discloses a multi-stranded optical fiber composite carbon fiber core temperature and strain decoupling method, system and device based on a multi-channel BOTDR, and a storage medium, and relates to the technical field of power transmission line state monitoring and optical fiber distributed sensing, and the method comprises the steps: calibrating the temperature and tension sensitivity coefficients of a built-in optical fiber of a lead in a laboratory; connecting each optical fiber to a multi-channel BOTDR system on site, and synchronously acquiring Brillouin frequency shift data along the line; establishing an equation set for each space point by using the calibration coefficient and the frequency shift data, and calculating a temperature variable quantity and an equivalent tension variable quantity through a least square method; by combining the material and geometric parameters of the carbon fiber core, the tensile force is converted into actual strain distribution, so that synchronous and distributed accurate monitoring of the temperature and the strain of the wire is realized; the optical fiber composite carbon fiber core wire state monitoring method is clear in mechanism, clear in implementation path and high in engineering adaptability, can remarkably improve the optical fiber composite carbon fiber core wire state monitoring technology level, and has good engineering application prospects.

Description

Technical Field

[0001] This invention relates to the field of power transmission line condition monitoring and fiber optic distributed sensing technology, and in particular to a method, system, device and storage medium for decoupling temperature and strain of multi-strand stranded optical fiber composite carbon fiber core based on multi-channel BOTDR. Background Technology

[0002] With the large-scale construction of inter-regional power transmission and ultra-high voltage lines, conductors operate under high tension, long spans, and complex meteorological environments for extended periods. Fiber optic composite carbon fiber core conductors, by embedding communication optical fibers within the carbon fiber composite core, not only improve the conductor's mechanical properties and current-carrying capacity but also provide a natural sensing medium for distributed monitoring of conductor status.

[0003] Existing methods for monitoring conductor condition mainly include conductor tension meters, tower foundation stress monitoring, visual sag measurement, wireless temperature measurement devices, and fiber optic grating (FBG) sensing. These methods typically suffer from problems such as complex deployment, power supply difficulties, limited monitoring distance, and weak resistance to electromagnetic interference, making them unsuitable for meeting the condition sensing needs of long-distance, all-weather operating lines. Distributed fiber optic sensing technology, with its advantages of single-end access, passive sensing, and long-distance continuous measurement, has been gradually applied to temperature or strain monitoring of transmission lines. For fiber-optic composite carbon fiber core conductors, the built-in fiber is sensitive to both temperature and axial strain: when the line is shifted by wind, experiences increased weight due to icing, or changes in operating conditions, the axial tension and strain of the carbon fiber core inside the conductor change, causing changes in the Brillouin frequency shift of the fiber; under varying ambient temperature conditions, significant changes in the Brillouin frequency shift occur; when monitoring the frequency shift using only a single built-in fiber, the contributions of temperature and strain to the frequency shift are coupled and difficult to distinguish, leading to errors in sag estimation. In existing technologies, temperature and strain are typically separated by assuming negligible temperature changes over a certain period or by introducing additional temperature-compensating optical fibers. However, in actual transmission line scenarios, temperature and tension often change simultaneously, making it difficult to find calibration conditions that are "purely temperature-dependent" or "purely strain-dependent." The superposition of multiple disturbances can lead to insufficient temperature compensation, thus affecting the accurate estimation of strain, sag, and icing loads. Fiber optic composite carbon fiber core conductors typically employ a structure of "central carbon core + multiple stranded carbon cores," where the axis of the central carbon fiber core coincides with the conductor axis, while the stranded carbon fiber cores are wound along the conductor axis at a certain helical angle. Under the same axial tensile force, the axial strain of the central carbon core and the axial strain of the stranded carbon core have a geometrically proportional relationship, exhibiting different mechanical response characteristics. However, existing monitoring methods have not fully utilized this difference to achieve decoupling of temperature and strain. Summary of the Invention

[0004] In view of the above-mentioned problems, the present invention provides a method, system, device and storage medium for decoupling temperature and strain of multi-stranded optical fiber composite carbon fiber core based on multi-channel BOTDR.

[0005] Therefore, the technical problem solved by this invention is: in the distributed monitoring of fiber optic composite carbon fiber core conductors, how to overcome the measurement inaccuracy caused by temperature and strain coupling without adding additional sensors, and achieve synchronous and high-precision decoupling of the temperature field and strain field along the conductor.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, the present invention provides a method for decoupling temperature and strain in a multi-stranded fiber composite carbon fiber core based on a multi-channel BOTDR, comprising: In a laboratory environment, the embedded optical fiber of the fiber-fiber composite carbon fiber core conductor was independently calibrated to obtain the sensitivity coefficient of the Brillouin frequency shift of the embedded optical fiber to temperature and tension. Each of the built-in optical fibers of the conductor is connected to a multi-channel BOTDR system for synchronous measurement to obtain the raw Brillouin frequency shift data of each channel distributed along the length of the conductor. Using the sensitivity coefficient of the Brillouin frequency shift of the built-in optical fiber to temperature and tension, and the original Brillouin frequency shift data, an overdetermined set of equations is established for each spatial point, and the temperature change and equivalent tension change are calculated by solving the least squares method. Based on the calculated temperature change and equivalent tensile force change, combined with the material and geometric parameters of the carbon fiber core, the actual strain distribution is converted.

[0007] As a preferred scheme for a temperature and strain decoupling method of multi-strand stranded optical fiber composite carbon fiber core based on multi-channel BOTDR, wherein: The process of independently calibrating the embedded optical fiber in the fiber-optic composite carbon fiber core conductor in a laboratory environment to obtain the sensitivity coefficient of the Brillouin frequency shift of the embedded optical fiber to temperature and tension includes: Take a section of wire containing a central carbon fiber core and at least one stranded carbon fiber core. The central carbon fiber core and each stranded carbon fiber core are pre-embedded with sensing optical fibers. In a laboratory setting, each sensing fiber was individually calibrated for temperature response to obtain the quantitative relationship between the Brillouin frequency shift and temperature for each fiber.

[0008] As a preferred scheme for a temperature and strain decoupling method of multi-strand stranded optical fiber composite carbon fiber core based on multi-channel BOTDR, wherein: The process of independently calibrating the embedded optical fiber in the fiber-optic composite carbon fiber core conductor in a laboratory environment to obtain the sensitivity coefficient of the Brillouin frequency shift of the embedded optical fiber to temperature and tension also includes: Under constant temperature conditions, axial tension was applied to the conductor sample segments, and the Brillouin frequency shift of the sensing fiber in the central carbon fiber core as a function of tension was calibrated, as well as the Brillouin frequency shift of each stranded carbon fiber core sensing fiber as a function of tension. The response relationships of the central carbon fiber core and the stranded carbon fiber core were different due to structural differences.

[0009] As a preferred scheme for a temperature and strain decoupling method of multi-strand stranded optical fiber composite carbon fiber core based on multi-channel BOTDR, wherein: The process of connecting each built-in optical fiber of the conductor to a multi-channel BOTDR system for synchronous measurement to obtain raw Brillouin frequency shift data of each channel distributed along the length of the conductor includes: The central carbon core embedded optical fiber and each stranded carbon core embedded optical fiber in the calibrated conductor are respectively connected to the multi-channel BOTDR system to form mutually independent optical fiber sensing channels. In the actual operation of the conductor, optical pulses are synchronously injected into each optical fiber sensing channel through a multi-channel BOTDR system, and backscattered light signals along the fiber length direction of each channel are synchronously collected. The acquired backscattered light signals from each channel are processed and demodulated synchronously to obtain the raw Brillouin frequency shift data distributed along the conductor length of the central carbon core embedded fiber and each stranded carbon core embedded fiber. The raw data contains distribution information in both spatial and temporal dimensions.

[0010] As a preferred scheme for a temperature and strain decoupling method of multi-strand stranded optical fiber composite carbon fiber core based on multi-channel BOTDR, wherein: The method utilizes the sensitivity coefficient of the Brillouin frequency shift of the built-in optical fiber to temperature and tension, along with the original Brillouin frequency shift data, to establish an overdetermined system of equations for each spatial point. These equations are then solved using the least squares method to calculate the temperature change and equivalent tension change, including: Based on the known response relationships of each sensing fiber to temperature and tension obtained from calibration, and the Brillouin frequency shift distribution data of each fiber along the conductor length obtained from real-time monitoring, the following operations are performed at each spatial point along the conductor: By taking advantage of the condition that all carbon fiber cores in the same cross section have the same temperature, the frequency shift change of the central optical fiber and at least two stranded optical fibers at this spatial point is used to construct a system of linear equations with the temperature change and equivalent tensile force change at this spatial point as unknowns. All equations share the same temperature response term, but each has a different tensile force response term due to the different carbon core structures of the optical fibers.

[0011] As a preferred scheme for a temperature and strain decoupling method of multi-strand stranded optical fiber composite carbon fiber core based on multi-channel BOTDR, wherein: The process of utilizing the sensitivity coefficient of the Brillouin frequency shift of the built-in optical fiber to temperature and tension, along with the original Brillouin frequency shift data, to establish an overdetermined system of equations for each spatial point, and then solving it using the least squares method to calculate the temperature change and equivalent tension change, also includes: Based on the frequency shift changes observed in the linear equation system, which contain more than a number of unknowns, the least squares estimation algorithm is used to solve the problem, thereby simultaneously calculating the estimated temperature change and the estimated equivalent tensile force change at that spatial point. By traversing all spatial points on the conductor, the temperature variation distribution and equivalent tensile force variation distribution along the entire length of the conductor can be obtained.

[0012] The beneficial effects of this preferred technical solution are as follows: by using the least squares method to process the overdetermined equation system, not only is a stable solution for the two unknowns achieved, but errors caused by random noise and local non-uniformity in single-channel measurement can also be effectively suppressed. The data redundancy significantly improves the anti-interference, stability and overall accuracy of the temperature and tension decoupling results.

[0013] As a preferred scheme for a temperature and strain decoupling method of multi-strand stranded optical fiber composite carbon fiber core based on multi-channel BOTDR, wherein: The calculated temperature change and equivalent tensile force change, combined with the material and geometric parameters of the carbon fiber core, are converted into the actual strain distribution, including: Based on the structural relationship between the central carbon fiber core and each stranded carbon fiber core in the conductor, a mechanical distribution model is established to distribute the equivalent total tensile force change to each carbon fiber core, so as to determine the tensile force change component acting on each carbon fiber core. Based on the material properties and geometric characteristics of each carbon fiber core, the axial strain of each carbon fiber core is calculated by the tensile force variation component. By integrating the axial strain information of the central carbon fiber core and all stranded carbon fiber cores, a strain field distributed along the length that characterizes the overall mechanical state of the conductor is obtained.

[0014] The beneficial effects of this preferred technical solution are as follows: the macroscopic tensile information obtained by decoupling is transformed into the specific microscopic strain distribution of each carbon fiber core according to a clear mechanical model, thereby directly linking the sensing information with the actual mechanical state of the conductor. This provides direct and reliable input data for accurate sag calculation based on strain, icing load assessment, and identification of anomalies such as local strand breakage, realizing the final value conversion from signal to state.

[0015] Secondly, the present invention provides a temperature and strain decoupling system for a multi-strand stranded optical fiber composite carbon fiber core based on a multi-channel BOTDR, comprising: The sensing coefficient calibration module is used to independently calibrate the built-in optical fiber of the fiber-optic composite carbon fiber core conductor in a laboratory environment, and obtain the sensitivity coefficient of the Brillouin frequency shift of the built-in optical fiber to temperature and tension. The multi-channel data acquisition module is used to connect each of the built-in optical fibers of the conductor to the multi-channel BOTDR system for synchronous measurement and to obtain the raw Brillouin frequency shift data of each channel distributed along the length of the conductor. The temperature strain decoupling module is used to establish an overdetermined set of equations for each spatial point by utilizing the sensitivity coefficient of the Brillouin frequency shift of the built-in optical fiber to temperature and tension, and the original Brillouin frequency shift data. The temperature change and the equivalent tension change are calculated by solving the least squares method. The mechanical parameter conversion module is used to convert the calculated temperature change and equivalent tensile force change into the actual strain distribution based on the material and geometric parameters of the carbon fiber core.

[0016] Thirdly, the present invention provides a computer device, comprising: Memory and processor; The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions. When the computer-executable instructions are executed by the processor, they implement the steps of the temperature and strain decoupling method of multi-strand stranded optical fiber composite carbon fiber core based on multi-channel BOTDR.

[0017] Fourthly, the present invention provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of a method for decoupling temperature and strain of a multi-stranded fiber composite carbon fiber core based on a multi-channel BOTDR.

[0018] The beneficial effects of this invention are as follows: This invention fully utilizes the different mechanical response characteristics of the central carbon core and the stranded carbon core under the same tensile force. By constructing a linear equation system of Brillouin frequency shift, temperature, and tensile force through multi-channel BOTDR (multi-channel Brillouin optical time-domain reflectometry), it achieves analytical separation of conductor temperature changes and tensile force changes, avoiding the shortcomings of traditional methods that rely on additional temperature compensation fibers or approximate assumptions. It directly utilizes the central fiber and stranded fiber pre-embedded inside the conductor for monitoring, without the need to add temperature or strain sensors to the outside of the conductor, nor to modify the conductor's shape and electrical performance, making it easy to promote and apply in existing fiber-optic composite carbon fiber core conductor projects. It can not only obtain the temperature and strain distribution along the line, but also further calculate the conductor sag, inter-tower tension, and additional loads, providing a unified data foundation for conductor sag over-limit early warning, icing risk assessment, and strand breakage diagnosis of stranded carbon fiber cores, realizing refined condition monitoring and early warning of transmission lines. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is an overall flowchart of a method for decoupling temperature and strain in a multi-stranded fiber composite carbon fiber core based on a multi-channel BOTDR, provided by the present invention. Detailed Implementation

[0021] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0022] Example 1, referring to Figure 1 This is the first embodiment of the present invention, which provides a method for decoupling temperature and strain in a multi-stranded fiber composite carbon fiber core based on a multi-channel BOTDR, comprising: S1: In a laboratory environment, the embedded optical fiber of the fiber-fiber composite carbon fiber core conductor is independently calibrated to obtain the sensitivity coefficient of the Brillouin frequency shift of the embedded optical fiber to temperature and tension. S2: Connect each of the built-in optical fibers of the conductor to the multi-channel BOTDR system for synchronous measurement to obtain the raw Brillouin frequency shift data of each channel distributed along the length of the conductor. S3: Using the sensitivity coefficient of the Brillouin frequency shift of the built-in optical fiber to temperature and tension and the original Brillouin frequency shift data, an overdetermined set of equations is established for each spatial point, and the temperature change and equivalent tension change are calculated by solving the least squares method. S4: Based on the calculated temperature change and equivalent tensile force change, combined with the material and geometric parameters of the carbon fiber core, it is converted into the actual strain distribution.

[0023] It should be noted that through steps S1-S4, an embedded, self-decoupled sensing system is constructed, which separates the mixed Brillouin frequency shift signal into independent temperature field and strain field information. Thus, without the need for any external sensors or ideal operating condition assumptions, high-precision, distributed, synchronous sensing of the state of fiber-optic composite carbon fiber core conductors is achieved, providing a direct and reliable underlying data foundation for the intelligent operation and maintenance of transmission lines.

[0024] Example 2, refer to Figure 1 As an embodiment of the present invention, based on the previous embodiment, a method for decoupling temperature and strain of a multi-stranded optical fiber composite carbon fiber core based on a multi-channel BOTDR is provided, comprising: In this embodiment, step S1 above, which involves independently calibrating the embedded optical fiber of the fiber-optic composite carbon fiber core conductor in a laboratory environment to obtain the sensitivity coefficient of the Brillouin frequency shift of the embedded optical fiber to temperature and tension, includes: Take a sample section of fiber-optic composite carbon fiber core conductor. The conductor consists of a central carbon fiber core and several stranded carbon fiber cores. The central carbon fiber core is arranged with a central optical fiber, and the stranded carbon fiber cores are arranged with stranded optical fibers respectively.

[0025] Under laboratory conditions, temperature calibration was performed on each embedded optical fiber to obtain the linear coefficient of Brillouin frequency shift with temperature change. That is, under the condition of no external tension, the Brillouin frequency shift of each optical fiber at different temperatures is measured, and the linear relationship between frequency shift and temperature is obtained by fitting.

[0026] Under isothermal conditions, tensile calibration was performed on the central carbon core fiber and the stranded carbon core fiber. By gradually increasing the axial tensile force and measuring the Brillouin frequency shift, the tensile calibration coefficient of the central carbon core fiber was obtained. and the tensile strength calibration coefficient of each stranded carbon core optical fiber. , where 𝑖 is the number of the stranded carbon fiber core.

[0027] Through the above calibration, the Brillouin frequency shift can be expressed as a linear superposition of temperature change and equivalent tensile force change.

[0028] In another possible implementation, when calibrating the built-in optical fiber independently, the two ends of the wire sample can be clamped and fixed on a dedicated calibration platform, and then the whole sample can be immersed in a temperature-controlled oil bath. By precisely controlling the oil bath temperature and using a distributed temperature measurement system to verify the uniformity of the cross-sectional temperature, the temperature coefficient of each optical fiber can be calibrated under the condition of completely eliminating the influence of air convection and ensuring a uniform temperature field.

[0029] In another possible implementation, when calibrating the embedded optical fiber independently, it can also be carried out by a separate calibration method, that is, using a miniature clamp to partially peel off a small section of a single carbon fiber core and its embedded optical fiber in the middle of the conductor sample, applying tension or temperature control only to the peeled section, while monitoring the frequency shift change of the optical fiber section, thereby obtaining a more independent tension and temperature sensitivity coefficient that excludes the influence of mechanical coupling between adjacent carbon cores.

[0030] In another possible implementation, when calibrating the temperature response, the conductor sample can be placed in a long-stroke, segmented, temperature-controlled tube furnace, so that different parts of the sample are under different stable temperature gradients. By performing a single BOTDR measurement, the frequency shift data of a single optical fiber at multiple different temperature points can be obtained simultaneously, thereby quickly fitting its temperature response curve and improving calibration efficiency.

[0031] In another possible implementation, when calibrating the temperature response, the reference fiber method can also be used. A standard reference fiber with a known temperature coefficient is placed in the middle of the calibration environment. By comparing the frequency shift changes of the fiber to be calibrated and the reference fiber in real time, the measurement error caused by the fluctuation of the ambient temperature control can be dynamically corrected and calibrated, thereby improving the accuracy of the calibration coefficient.

[0032] In this embodiment, step S2 above involves connecting each of the embedded optical fibers of the conductor to a multi-channel BOTDR system for synchronous measurement, obtaining raw Brillouin frequency shift data for each channel distributed along the conductor length, including: Connect the connectors of the central carbon core embedded optical fiber and the multiple stranded carbon core embedded optical fibers to the multi-channel BOTDR system to achieve synchronous monitoring of the central optical fiber channel and the stranded optical fiber channel.

[0033] Specifically, under actual operating conditions of the conductor, pulsed light is periodically injected into each channel to collect Brillouin backscattered signals along the line, and the spatial distribution of Brillouin frequency shift of the central fiber and each stranded fiber is obtained through system processing. and , where z is the spatial location and t is the time.

[0034] In another possible implementation, the multi-channel BOTDR system can also be constructed by configuring a host to integrate multiple independent detection modules, where each detection module (such as the corresponding central fiber channel, twisted fiber channel 1, channel 2, etc.) has an independent laser, modulator, detector and data acquisition card, and is controlled and synchronized by a unified main control unit, thereby realizing the physical isolation of each fiber channel and the completely parallel signal acquisition and processing.

[0035] In another possible implementation, the multi-channel BOTDR system can also be constructed by using a single transceiver device that combines wavelength division multiplexing with time division multiplexing. A broadband tunable laser is combined with multiple acousto-optic modulators to assign different optical pulse coding sequences or wavelength windows to each access sensing fiber. The backscattered light is demultiplexed and received by the same high-speed detector. Then, the Brillouin frequency shift information of each channel is separated and calculated in the time and frequency domains by digital signal processing algorithms.

[0036] In another possible implementation, when synchronously injecting optical pulses, a master clock module can be used to generate a highly stable electrical trigger signal and simultaneously distribute this signal to the driving circuits of each independent light source in the multi-channel BOTDR system. Through precise delay compensation calibration, it is ensured that the optical pulses of all channels achieve nanosecond-level synchronization accuracy when leaving the laser output end face, thereby realizing strict hardware synchronization triggering.

[0037] In another possible implementation, when synchronously injecting optical pulses, a software-defined master-slave synchronization protocol can be used, designating one channel as the master channel. Its pulse emission events are broadcast in real time to other slave channels via a high-speed communication bus (such as a customized backplane). After receiving the instruction, each slave channel immediately triggers pulse emission according to its own preset fixed delay. The system maintains the stability of this synchronization relationship through periodic measurement and calibration.

[0038] In this embodiment, in step S3 above, the sensitivity coefficient of the Brillouin frequency shift of the built-in optical fiber to temperature and tension, and the original Brillouin frequency shift data, are used to establish an overdetermined system of equations for each spatial point, and the temperature change and equivalent tension change are calculated by solving the least squares method. Assuming that the temperature changes of the central carbon core and the stranded carbon core are the same within the same cross-section, for any spatial location z of the central fiber and the i-th stranded fiber, we have the following observation vector: Solve for the vectors (temperature change, equivalent tensile force change): The linear relationship of the Brillouin frequency shift can be written out separately: in, The change in Brillouin frequency shift of the central carbon core optical fiber relative to the reference state; The Brillouin frequency shift of a certain stranded carbon core optical fiber; This represents the change in conductor temperature at that location relative to a reference state. This represents the change in the equivalent axial tensile force borne by the carbon fiber core at that location. This is the temperature calibration coefficient; , These are the tensile calibration coefficients for the central carbon core fiber and the stranded carbon core fiber, respectively.

[0039] In matrix coefficient form, we have: The coefficient matrix H is as follows: in, It is an error vector that includes the combined effects of measurement noise, local structural differences, etc.

[0040] From a physical perspective, the coefficient matrix The first column corresponds to the temperature coefficient, which is almost the same in the central fiber and each stranded fiber; the second column corresponds to the "contribution of tension to frequency shift". Since the central carbon fiber core is arranged in a straight line and the stranded carbon fiber core is a helical rod with a helical angle, its axial stiffness is equivalent to... , making , different.

[0041] In an ideal scenario, a 2×2 matrix equation can be constructed using only a single stranded fiber and a center fiber: get ,Right now: In practical engineering applications, to improve noise immunity and reduce errors caused by local structural differences, this invention utilizes six stranded carbon-core optical fibers to construct a set of equations, and solves for temperature and tension using least-squares estimation. Specifically, the least-squares solution can be given by the following formula: in, These are estimates of the temperature and tensile force changes at this cross-section. This is a diagonal weighting matrix used to weight the measurement noise of each channel. By introducing redundancy information from six stranded carbon fiber cores, this invention can average and suppress random noise and local stress inhomogeneity in a single stranded fiber, significantly reducing the uncertainty of the temperature and tension decoupling results.

[0042] Therefore, based on the Brillouin frequency shift data acquired by a multi-channel BOTDR, the temperature changes at each cross-section along the line can be obtained through the aforementioned matrix equations and least squares solution process. and equivalent tensile force change .

[0043] In this embodiment, step S4 above, based on the calculated temperature change and equivalent tensile force change, combined with the material and geometric parameters of the carbon fiber core, converts the results into the actual strain distribution, including: Based on the calculated temperature change and equivalent tensile force change, and combined with the material and geometric parameters of the carbon fiber core, the strain of the central carbon core and the stranded carbon core is further calculated: The central carbon fiber core can be represented as: in, For the axial strain of the central carbon fiber core, The elastic modulus of the central carbon fiber core, The cross-sectional area of ​​the central carbon fiber core, This refers to the change in tensile force distributed to the central carbon fiber core.

[0044] For a spirally wound stranded carbon fiber core, under the action of axial tension in the conductor, its axial stiffness can be equivalent to... ,in The elastic modulus of the stranded carbon fiber core material. For the cross-sectional area, If the helix angle is given, then the equivalent axial strain of the stranded carbon fiber core can be expressed as: The change in total tensile force is calculated using a model. By rationally distributing the carbon core between the central carbon core and each stranded carbon core, the strain distribution of each carbon fiber core is obtained, thereby obtaining the strain field information of the entire conductor cross-section.

[0045] Example 3 illustrates a schematic scheme of a temperature and strain decoupling method for multi-stranded fiber composite carbon fiber core based on a multi-channel BOTDR. It should be noted that the technical solution of a multi-stranded fiber composite carbon fiber core temperature and strain decoupling system based on a multi-channel BOTDR is based on the same concept as the aforementioned technical solution of a multi-stranded fiber composite carbon fiber core temperature and strain decoupling method based on a multi-channel BOTDR. Details not described in detail in the technical solution of the multi-stranded fiber composite carbon fiber core temperature and strain decoupling system based on a multi-channel BOTDR in this embodiment can be found in the description of the aforementioned technical solution of a multi-stranded fiber composite carbon fiber core temperature and strain decoupling method based on a multi-channel BOTDR.

[0046] This embodiment also provides a temperature and strain decoupling system for a multi-strand stranded optical fiber composite carbon fiber core based on a multi-channel BOTDR, including: The sensing coefficient calibration module is used to independently calibrate the built-in optical fiber of the fiber-optic composite carbon fiber core conductor in a laboratory environment, and obtain the sensitivity coefficient of the Brillouin frequency shift of the built-in optical fiber to temperature and tension. The multi-channel data acquisition module is used to connect each of the built-in optical fibers of the conductor to the multi-channel BOTDR system for synchronous measurement and to obtain the raw Brillouin frequency shift data of each channel distributed along the length of the conductor. The temperature strain decoupling module is used to establish an overdetermined set of equations for each spatial point by utilizing the sensitivity coefficient of the Brillouin frequency shift of the built-in optical fiber to temperature and tension, and the original Brillouin frequency shift data. The temperature change and the equivalent tension change are calculated by solving the least squares method. The mechanical parameter conversion module is used to convert the calculated temperature change and equivalent tensile force change into the actual strain distribution based on the material and geometric parameters of the carbon fiber core.

[0047] This embodiment also provides an electronic device applicable to a method for decoupling temperature and strain in a multi-strand stranded optical fiber composite carbon fiber core based on a multi-channel BOTDR, including: The memory and processor are used to store computer-executable instructions and execute computer-executable instructions to implement the temperature and strain decoupling method of multi-strand stranded optical fiber composite carbon fiber core based on multi-channel BOTDR proposed in the above embodiments.

[0048] This embodiment also provides a storage medium storing a computer program that, when executed by a processor, implements a method for decoupling temperature and strain of a multi-stranded fiber composite carbon fiber core based on a multi-channel BOTDR as proposed in the above embodiment.

[0049] The storage medium proposed in this embodiment belongs to the same inventive concept as the temperature and strain decoupling method of multi-strand stranded optical fiber composite carbon fiber core based on multi-channel BOTDR proposed in the above embodiment. Technical details not described in detail in this embodiment can be found in the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0050] 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 it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for decoupling temperature and strain in a multi-stranded fiber composite carbon fiber core based on a multi-channel BOTDR, characterized in that, include: In a laboratory environment, the embedded optical fiber of the fiber-fiber composite carbon fiber core conductor was independently calibrated to obtain the sensitivity coefficient of the Brillouin frequency shift of the embedded optical fiber to temperature and tension. Each of the built-in optical fibers of the conductor is connected to a multi-channel BOTDR system for synchronous measurement to obtain the raw Brillouin frequency shift data of each channel distributed along the length of the conductor. Using the sensitivity coefficient of the Brillouin frequency shift of the built-in optical fiber to temperature and tension, and the original Brillouin frequency shift data, an overdetermined set of equations is established for each spatial point, and the temperature change and equivalent tension change are calculated by solving the least squares method. Based on the calculated temperature change and equivalent tensile force change, combined with the material and geometric parameters of the carbon fiber core, the actual strain distribution is converted.

2. The method for decoupling temperature and strain of a multi-stranded fiber composite carbon fiber core based on a multi-channel BOTDR as described in claim 1, characterized in that, The process of independently calibrating the embedded optical fiber in the fiber-optic composite carbon fiber core conductor in a laboratory environment to obtain the sensitivity coefficient of the Brillouin frequency shift of the embedded optical fiber to temperature and tension includes: Take a section of wire containing a central carbon fiber core and at least one stranded carbon fiber core. The central carbon fiber core and each stranded carbon fiber core are pre-embedded with sensing optical fibers. In a laboratory setting, each sensing fiber was individually calibrated for temperature response to obtain the quantitative relationship between the Brillouin frequency shift and temperature for each fiber.

3. The method for decoupling temperature and strain of a multi-stranded fiber composite carbon fiber core based on a multi-channel BOTDR as described in claim 2, characterized in that... The process of independently calibrating the embedded optical fiber in the fiber-optic composite carbon fiber core conductor in a laboratory environment to obtain the sensitivity coefficient of the Brillouin frequency shift of the embedded optical fiber to temperature and tension also includes: Under constant temperature conditions, axial tension was applied to the conductor sample segments, and the Brillouin frequency shift of the sensing fiber in the central carbon fiber core as a function of tension was calibrated, as well as the Brillouin frequency shift of each stranded carbon fiber core sensing fiber as a function of tension. The response relationships of the central carbon fiber core and the stranded carbon fiber core were different due to structural differences.

4. The method for decoupling temperature and strain of a multi-stranded optical fiber composite carbon fiber core based on a multi-channel BOTDR as described in claim 3, characterized in that, The process of connecting each built-in optical fiber of the conductor to a multi-channel BOTDR system for synchronous measurement to obtain raw Brillouin frequency shift data of each channel distributed along the length of the conductor includes: The central carbon core embedded optical fiber and each stranded carbon core embedded optical fiber in the calibrated conductor are respectively connected to the multi-channel BOTDR system to form mutually independent optical fiber sensing channels. In the actual operation of the conductor, optical pulses are synchronously injected into each optical fiber sensing channel through a multi-channel BOTDR system, and backscattered light signals along the fiber length direction of each channel are synchronously collected. The acquired backscattered light signals from each channel are processed and demodulated synchronously to obtain the raw Brillouin frequency shift data distributed along the conductor length of the central carbon core embedded fiber and each stranded carbon core embedded fiber. The raw data contains distribution information in both spatial and temporal dimensions.

5. The method for decoupling temperature and strain of a multi-stranded fiber composite carbon fiber core based on a multi-channel BOTDR as described in claim 4, characterized in that... The method utilizes the sensitivity coefficient of the Brillouin frequency shift of the built-in optical fiber to temperature and tension, along with the original Brillouin frequency shift data, to establish an overdetermined system of equations for each spatial point. These equations are then solved using the least squares method to calculate the temperature change and equivalent tension change, including: Based on the known response relationships of each sensing fiber to temperature and tension obtained from calibration, and the Brillouin frequency shift distribution data of each fiber along the conductor length obtained from real-time monitoring, the following operations are performed at each spatial point along the conductor: By taking advantage of the condition that all carbon fiber cores in the same cross section have the same temperature, the frequency shift change of the central optical fiber and at least two stranded optical fibers at this spatial point is used to construct a system of linear equations with the temperature change and equivalent tensile force change at this spatial point as unknowns. All equations share the same temperature response term, but each has a different tensile force response term due to the different carbon core structures of the optical fibers.

6. The method for decoupling temperature and strain of a multi-stranded fiber composite carbon fiber core based on a multi-channel BOTDR as described in claim 5, characterized in that... The process of utilizing the sensitivity coefficient of the Brillouin frequency shift of the built-in optical fiber to temperature and tension, along with the original Brillouin frequency shift data, to establish an overdetermined system of equations for each spatial point, and then solving it using the least squares method to calculate the temperature change and equivalent tension change, also includes: Based on the frequency shift changes observed in the linear equation system, which contain more than a number of unknowns, the least squares estimation algorithm is used to solve the problem, thereby simultaneously calculating the estimated temperature change and the estimated equivalent tensile force change at that spatial point. By traversing all spatial points on the conductor, the temperature variation distribution and equivalent tensile force variation distribution along the entire length of the conductor can be obtained.

7. The method for decoupling temperature and strain of a multi-stranded optical fiber composite carbon fiber core based on a multi-channel BOTDR as described in claim 6, characterized in that, The calculated temperature change and equivalent tensile force change, combined with the material and geometric parameters of the carbon fiber core, are converted into the actual strain distribution, including: Based on the structural relationship between the central carbon fiber core and each stranded carbon fiber core in the conductor, a mechanical distribution model is established to distribute the equivalent total tensile force change to each carbon fiber core, so as to determine the tensile force change component acting on each carbon fiber core. Based on the material properties and geometric characteristics of each carbon fiber core, the axial strain of each carbon fiber core is calculated by the tensile force variation component. By integrating the axial strain information of the central carbon fiber core and all stranded carbon fiber cores, a strain field distributed along the length that characterizes the overall mechanical state of the conductor is obtained.

8. A temperature and strain decoupling system for a multi-strand stranded optical fiber composite carbon fiber core based on a multi-channel BOTDR, using the method described in any one of claims 1 to 7, characterized in that, include: The sensing coefficient calibration module is used to independently calibrate the built-in optical fiber of the fiber-optic composite carbon fiber core conductor in a laboratory environment, and obtain the sensitivity coefficient of the Brillouin frequency shift of the built-in optical fiber to temperature and tension. The multi-channel data acquisition module is used to connect each of the built-in optical fibers of the conductor to the multi-channel BOTDR system for synchronous measurement and to obtain the raw Brillouin frequency shift data of each channel distributed along the length of the conductor. The temperature strain decoupling module is used to establish an overdetermined set of equations for each spatial point by utilizing the sensitivity coefficient of the Brillouin frequency shift of the built-in optical fiber to temperature and tension, and the original Brillouin frequency shift data. The temperature change and the equivalent tension change are calculated by solving the least squares method. The mechanical parameter conversion module is used to convert the calculated temperature change and equivalent tensile force change into the actual strain distribution based on the material and geometric parameters of the carbon fiber core.

9. An electronic device, characterized in that, include: Memory and processor; The memory is used to store computer-executable instructions, and the processor is used to execute the computer-executable instructions, which, when executed by the processor, implement the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, It stores computer-executable instructions that, when executed by a processor, implement the steps of the method according to any one of claims 1 to 7.

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