A distribution network communication method and system based on remote access network

Abstract

The present invention relates to the field of distribution network communication technology, and in particular to a distribution network communication method and system based on a remote access network, including identifying attenuation fault points caused by optical fiber bending stress; evaluating optical fiber signal transmission quality through attenuation fault points to obtain signal transmission quality indicators; simulating the non-uniform distribution of optical fiber refractive index using variational finite element method to obtain the law of energy coupling variation between modes; performing dynamic power pre-compensation on the optical fiber link quality based on the law of energy coupling variation between modes and signal transmission quality indicators to obtain the optical power compensation amount; connecting the master station in the distribution automation system with the measurement and control terminal of the remote access network through a communication link, and compensating and controlling the communication link according to the optical power compensation amount. By introducing dynamic power pre-compensation technology, the present invention can quickly respond to changes in link status and ensure the continuity and stability of the communication link between the master station and the measurement and control terminal of the remote access network in the distribution automation system.

Description

Technical Field

[0001] The present invention relates to the field of power distribution network communication technology, and in particular to a power distribution network communication method and system based on a remote access network. Background Art

[0002] In the power system, the distribution communication network is a key link connecting power grids at all levels and terminal equipment. Its stability and reliability are crucial to ensuring the continuity and efficiency of power supply. As an important part of the distribution communication network, the optical fiber network plays an irreplaceable role in data transmission with its high bandwidth and low loss characteristics. However, in the actual deployment and operation and maintenance process, the optical fiber transmission link faces many challenges from external environmental factors, especially the problem of optical fiber bending stress, which has become one of the key factors affecting the quality of distribution communication. During the laying process of optical fiber, it is inevitable that it will be restricted by various factors such as terrain, buildings, and construction, resulting in bending and deformation of the optical fiber. When the bending radius of the optical fiber is reduced to a critical value, the stress distribution inside the optical fiber will no longer be uniform, which will cause non-uniform changes in the refractive index of the core. This non-uniform distribution of the refractive index not only destroys the original transmission characteristics of the optical fiber, but also aggravates the energy coupling phenomenon between different transmission modes in the optical fiber. Specifically, the energy of the high-order mode will be transferred more to the low-order mode, and the low-order mode will couple the energy to the radiation mode with higher attenuation, which will eventually lead to a significant increase in the loss of the optical signal during transmission, affecting the integrity and clarity of the communication signal.

[0003] To address this problem, although the existing technology has proposed to use dynamic power pre-compensation technology to compensate for the additional loss caused by optical fiber bending, this solution still faces many challenges in practical applications. On the one hand, the response speed and accuracy of the compensation mechanism are difficult to meet the requirements of real-time transmission, especially in large-span and long-distance application scenarios such as remote access networks. Due to the complexity and uncertainty of the signal transmission path, the compensation effect is often greatly reduced. On the other hand, the implementation cost of dynamic power pre-compensation technology is high and requires complex algorithm support. This increases the complexity and cost of operation and maintenance for distribution communication systems with limited resources. Therefore, how to effectively deal with the impact of optical fiber bending stress on distribution communication networks has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a distribution network communication method and system based on a remote access network.

[0005] In a first aspect, the present invention provides a distribution network communication method based on a remote access network, the method comprising the following steps:

[0006] According to the attenuation characteristics of the optical fiber transmission link in the distribution automation system, the optical fiber link fault detection is carried out to identify the attenuation fault point caused by the optical fiber bending stress;

[0007] The optical fiber signal transmission quality is evaluated by using the fault characteristics at the attenuation fault point to obtain a signal transmission quality index;

[0008] The variational finite element method is used to simulate the non-uniform distribution of the optical fiber refractive index, and the variation law of inter-mode energy coupling under different optical fiber bending radius and stress distribution is obtained;

[0009] Based on the inter-mode energy coupling variation law and the signal transmission quality index, dynamic power pre-compensation is performed on the optical fiber link quality to obtain the optical power compensation amount required for each attenuation fault point;

[0010] A master station in the power distribution automation system is connected to a measurement and control terminal of a remote access network via a communication link, and compensation control is performed on the communication link according to the optical power compensation amount.

[0011] In a further embodiment, the step of performing fault detection on the optical fiber link according to the attenuation characteristics of the optical fiber transmission link in the power distribution automation system and identifying the attenuation fault point caused by the optical fiber bending stress comprises:

[0012] Collecting reflected signal waveform data in the optical fiber link in the power distribution automation system, and using a median filter to eliminate baseline noise on the reflected signal waveform data to obtain a reflected signal baseline curve;

[0013] According to the reflected signal baseline curve, dispersion compensation processing is performed on the reflected signal waveform data by using a preset dispersion compensation coefficient to obtain compensated waveform data;

[0014] Performing noise reduction filtering on the compensation waveform data using a multi-scale wavelet decomposition algorithm to obtain a filtered reflection signal;

[0015] Extracting attenuation feature points in the optical fiber link according to the filtered reflection signal and a preset attenuation feature recognition threshold;

[0016] Optical frequency domain reflection technology is used to measure the forward and reverse reflection waveforms of the attenuation characteristic points to locate and identify the attenuation fault points caused by optical fiber bending stress.

[0017] In a further embodiment, the step of evaluating the optical fiber signal transmission quality by the fault characteristics at the attenuation fault point to obtain the signal transmission quality index comprises:

[0018] Establishing an attenuation point characteristic curve according to the fault characteristics at the attenuation fault point, and establishing a stress attenuation characteristic library using optical fiber microbending theory;

[0019] Performing an attenuation pattern matching operation on the attenuation point characteristic curve and the stress attenuation characteristic library to obtain a pattern matching result;

[0020] According to the mode matching result and the optical fiber micro-bending loss theory, the attenuation of the attenuation fault point is calculated;

[0021] Based on the attenuation of the attenuation fault point, a convolutional neural network is used to analyze the optical fiber stress distribution at the attenuation fault point to quantify the degree of optical fiber bending stress fault;

[0022] The optical fiber signal transmission quality is evaluated according to the degree of the optical fiber bending stress failure to obtain a signal transmission quality index.

[0023] In a further embodiment, the step of simulating the non-uniform distribution of the optical fiber refractive index using the variational finite element method to obtain the variation law of energy coupling between modes under different optical fiber bending radii and stress distributions includes:

[0024] The basic refractive index at the attenuation fault point is measured by using a Bragg reflection spectrometer, and the optical fiber strain data generated by the optical fiber around the attenuation fault point under the action of bending stress is measured by using a strain sensing optical fiber array;

[0025] According to the optical fiber strain data, the refractive index increment distribution data corresponding to the strain field is obtained by using the elastic-optic effect theory;

[0026] According to the basic refractive index and the refractive index increment distribution data, coupling and solving the stress field of the optical fiber cross section and the refractive index field are performed to obtain the stress distribution of the optical fiber cross section;

[0027] Based on the stress distribution of the optical fiber cross section, the non-uniform distribution of the optical fiber refractive index is simulated using the variational finite element method to obtain the variation law of the mode coupling intensity under different stress distributions;

[0028] According to the variation law of mode coupling intensity under different stress distributions, the recursive least squares method is used to analyze the influence of fiber bending in a two-dimensional plane on the inter-mode energy coupling, and the variation law of inter-mode energy coupling under different fiber bending radii and stress distributions is obtained.

[0029] In a further embodiment, the step of coupling and solving the stress field and the refractive index field of the optical fiber cross section according to the basic refractive index and the refractive index increment distribution data to obtain the stress distribution of the optical fiber cross section comprises:

[0030] According to the basic refractive index of the fault point and the refractive index increment distribution data, a tetrahedral mesher is used to perform unstructured meshing on the optical fiber cross section to form an optical fiber core-cladding boundary;

[0031] Analyze the linear relationship between optical fiber stress and refractive index increment according to the refractive index increment distribution data to obtain the refractive index change law of the optical fiber under stress;

[0032] The continuity boundary condition of the fiber core-cladding boundary is set, and the stress field and refractive index field of the fiber cross section are coupled and solved based on the law of refractive index change of the fiber under stress to obtain the stress distribution of the fiber cross section.

[0033] In a further embodiment, the step of simulating the non-uniform distribution of the optical fiber refractive index using the variational finite element method based on the stress distribution of the optical fiber cross section to obtain the variation law of the mode coupling intensity under different stress distributions includes:

[0034] According to the stress distribution of the optical fiber cross section, the non-uniform distribution of the refractive index of the optical fiber under bending stress is simulated by using the variational finite element method to obtain the refractive index field distribution of the optical fiber cross section;

[0035] Calculating the power coupling coefficient between the fundamental mode and the high-order mode in the optical fiber by using a wave equation according to the refractive index field distribution of the optical fiber cross section;

[0036] According to the stress distribution of the optical fiber cross section, the stress distribution law of the optical fiber in radial and circumferential directions is obtained by using the boundary element method;

[0037] According to the power coupling coefficient and the stress distribution law of the optical fiber in the radial direction and the circumferential direction, the variation law of the mode coupling intensity under different stress distributions is obtained.

[0038] In a further embodiment, the optical fiber strain data includes axial strain data and transverse strain data generated by the optical fiber under bending stress.

[0039] In a further embodiment, the step of performing dynamic power pre-compensation on the optical fiber link quality based on the inter-mode energy coupling variation law and the signal transmission quality index to obtain the optical power compensation amount required for each attenuation fault point includes:

[0040] Using an optical fiber temperature sensor array to collect ambient temperature data at the attenuation fault point, and performing temperature compensation on the stress distribution of the optical fiber cross section according to the ambient temperature data to obtain an optical fiber stress correction distribution diagram;

[0041] According to the optical fiber stress correction distribution diagram, the optical fiber stress loss value is calculated by using the inter-mode energy coupling variation law;

[0042] According to the ambient temperature data, the temperature transmission loss value caused by temperature is converted by the temperature refractive index coefficient of the optical fiber material, and the optical fiber stress loss value and the temperature transmission loss value are superimposed by a random forest regressor to obtain the total transmission loss of the optical fiber link;

[0043] According to the total transmission loss of the optical fiber link and the signal transmission quality index, a long short-term memory neural network is used to predict the optical power attenuation trend;

[0044] According to the optical power attenuation trend and a predetermined target optical power value, an optical power compensation amount required for each attenuation fault point is obtained.

[0045] In a further embodiment, the step of performing compensation control on the communication link according to the optical power compensation amount comprises:

[0046] According to the optical power compensation amount, the communication link is compensated by an optical power equalizer, and the backup optical path switching is started when the communication is interrupted.

[0047] In a second aspect, the present invention provides a distribution network communication system based on a remote access network, the system comprising:

[0048] A fault identification module is used to detect faults in optical fiber links according to the attenuation characteristics of optical fiber transmission links in the power distribution automation system, and to identify attenuation fault points caused by optical fiber bending stress;

[0049] A signal evaluation module, used to evaluate the optical fiber signal transmission quality through the fault characteristics at the attenuation fault point to obtain a signal transmission quality index;

[0050] The coupling analysis module is used to simulate the non-uniform distribution of the optical fiber refractive index using the variational finite element method to obtain the variation law of inter-mode energy coupling under different optical fiber bending radii and stress distributions;

[0051] A compensation analysis module, used to perform dynamic power pre-compensation on the optical fiber link quality based on the inter-mode energy coupling variation law and the signal transmission quality index, and obtain the optical power compensation amount required for each attenuation fault point;

[0052] The compensation control module is used to connect the master station in the distribution automation system with the measurement and control terminal of the remote access network through a communication link, and to perform compensation control on the communication link according to the optical power compensation amount.

[0053] The present invention provides a distribution network communication method and system based on a remote access network. The method detects faults of optical fiber links according to the attenuation characteristics of optical fiber transmission links in a distribution automation system, identifies attenuation fault points caused by optical fiber bending stress; evaluates optical fiber signal transmission quality according to the fault characteristics at the attenuation fault points, and obtains signal transmission quality indicators; simulates the non-uniform distribution of optical fiber refractive index using a variational finite element method, and obtains the law of energy coupling variation between modes under different optical fiber bending radii and stress distributions; performs dynamic power pre-compensation on optical fiber link quality based on the law of energy coupling variation between modes and the signal transmission quality indicators, and obtains the optical power compensation required for each attenuation fault point; connects the master station in the distribution automation system with the measurement and control terminal of the remote access network through a communication link, and performs compensation control on the communication link according to the optical power compensation amount. Compared with the prior art, the method can effectively improve the reliability and stability of the communication link between the master station and the measurement and control terminal of the remote access network in the distribution automation system, and is of great significance for ensuring the safe operation of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a schematic diagram of a flow chart of a distribution network communication method based on a remote access network provided by an embodiment of the present invention;

[0055] Figure 2 It is a block diagram of a distribution network communication system based on a remote access network provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0056] The following specifically illustrates the implementation mode of the present invention in conjunction with the accompanying drawings. The embodiments are provided for illustrative purposes only and are not to be construed as limitations of the present invention. The accompanying drawings are provided for reference and illustration only and do not constitute limitations on the scope of patent protection of the present invention, because many changes may be made to the present invention without departing from the spirit and scope of the present invention.

[0057] refer to Figure 1 , an embodiment of the present invention provides a distribution network communication method based on a remote access network, such as Figure 1 As shown, the method comprises the following steps:

[0058] S1. Perform fault detection on the optical fiber link according to the attenuation characteristics of the optical fiber transmission link in the distribution automation system, and identify the attenuation fault point caused by the optical fiber bending stress.

[0059] In this embodiment, the step of performing fault detection on the optical fiber link according to the attenuation characteristics of the optical fiber transmission link in the power distribution automation system and identifying the attenuation fault point caused by the optical fiber bending stress includes:

[0060] Collecting reflected signal waveform data in the optical fiber link in the power distribution automation system, and using a median filter to eliminate baseline noise on the reflected signal waveform data to obtain a reflected signal baseline curve;

[0061] According to the reflected signal baseline curve, dispersion compensation processing is performed on the reflected signal waveform data by using a preset dispersion compensation coefficient to obtain compensated waveform data;

[0062] Performing noise reduction filtering on the compensation waveform data using a multi-scale wavelet decomposition algorithm to obtain a filtered reflection signal;

[0063] Extracting attenuation feature points in the optical fiber link according to the filtered reflection signal and a preset attenuation feature recognition threshold;

[0064] Optical frequency domain reflection technology is used to measure the forward and reverse reflection waveforms of the attenuation characteristic points to locate and identify the attenuation fault points caused by optical fiber bending stress.

[0065] Specifically, this embodiment uses an optical transmitter to inject a standard test optical signal with a wavelength of 1550 nanometers and a pulse width of 10 nanoseconds into the optical fiber link of the distribution automation system, and collects 512 sampling point data at a sampling frequency of 2.5 GHz through an optical time domain reflectometer to obtain reflection signal waveform data. For the collected reflection signal waveform data, this embodiment uses a median filter to eliminate baseline noise to obtain a reflection signal baseline curve of the optical fiber link. Based on the reflection signal baseline curve, a preset dispersion compensation coefficient is used to perform dispersion compensation processing on the reflection signal waveform data to reduce waveform distortion and obtain compensated waveform data. A multi-scale wavelet decomposition algorithm is used to perform noise reduction filtering on the compensated waveform data to obtain a filtered reflection signal. An attenuation feature recognition threshold is set for the filtered reflection signal. For example, the attenuation feature recognition threshold is set to 0.3 decibels per kilometer. The signal change point above the attenuation feature recognition threshold is the potential fault point, thereby extracting the attenuation feature point in the optical fiber link. It should be noted that the optical During the transmission process, the optical fiber signal may weaken due to various factors (such as optical fiber bending, connection loss, etc.). This reduction in signal strength is called attenuation. The optical signal in the optical fiber will be reflected at the bend to form a reflection waveform. In this embodiment, by measuring the forward and reverse reflection waveforms, the optical signal characteristics at different positions in the optical fiber can be obtained. Specifically, according to the extracted attenuation feature points, the optical frequency domain reflectometry (OFDR) technology is used to measure the forward and reverse reflection waveforms of the optical fiber. The precise position of the attenuation fault point in the optical fiber link is obtained by bidirectional measurement and calculation of the forward reflection waveform and the reverse reflection waveform. In the bidirectional measurement, the attenuation feature point is manifested as a significant reduction in signal strength or an obvious change in waveform. These feature points are related to the attenuation fault caused by the bending stress of the optical fiber. By comparing the forward and reverse reflection waveforms, the attenuation fault point caused by the bending stress of the optical fiber can be more accurately located. In this embodiment, the attenuation fault point position is obtained by multiplying the time difference between the forward reflection waveform and the reverse reflection waveform by the speed of light.

[0066] S2. Evaluate the optical fiber signal transmission quality based on the fault characteristics at the attenuation fault point to obtain a signal transmission quality index.

[0067] In this embodiment, the step of evaluating the optical fiber signal transmission quality by using the fault characteristics at the attenuation fault point to obtain the signal transmission quality index includes:

[0068] Establishing an attenuation point characteristic curve according to the fault characteristics at the attenuation fault point, and establishing a stress attenuation characteristic library using optical fiber microbending theory;

[0069] Performing an attenuation pattern matching operation on the attenuation point characteristic curve and the stress attenuation characteristic library to obtain a pattern matching result;

[0070] According to the mode matching result and the optical fiber microbending loss theory, the attenuation of the attenuation fault point is calculated;

[0071] Based on the attenuation of the attenuation fault point, a convolutional neural network is used to analyze the optical fiber stress distribution at the attenuation fault point to quantify the degree of optical fiber bending stress fault;

[0072] The optical fiber signal transmission quality is evaluated according to the degree of the optical fiber bending stress failure to obtain a signal transmission quality index.

[0073] Specifically, the present embodiment collects the characteristics of each attenuation fault point in the optical fiber, including but not limited to parameters such as position, attenuation, and wavelength, and then uses polynomial fitting to fit the extracted characteristics into an attenuation point characteristic curve, and establishes a stress attenuation characteristic library containing the relationship between optical fiber stress and attenuation under different conditions (such as different bending radii, different material properties, etc.) based on the optical fiber micro-bending theory, and performs a matching operation on the attenuation point characteristic curve and the pattern in the stress characteristic library, and uses the correlation coefficient method to determine the similarity between the two, and determine whether the attenuation point is caused by the optical fiber bending stress, and obtains the pattern matching result. For example, if the correlation coefficient is greater than 0.9, it is considered that the pattern matching result is that the attenuation fault point is caused by the optical fiber bending stress, and then, based on the optical fiber micro-bending loss theory and the pattern matching result, the relationship between the optical fiber bending radius and the stress distribution thereon is established to quantify the optical fiber bending stress. Regarding the influence of signal attenuation, the specific attenuation of each attenuation fault point is calculated using the reflected signal power attenuation formula to quantify the degree of loss of the optical fiber signal at a specific attenuation fault point. According to the attenuation of each attenuation fault point, a convolutional neural network is used to analyze the optical fiber stress distribution at the attenuation fault point. In this embodiment, the optical fiber bending stress fault point can be quantitatively graded according to the area of ​​the optical fiber stress distribution curve. The larger the area, the greater the stress on the optical fiber in the area, and the more serious the signal attenuation caused. The degree of optical fiber bending stress failure is a quantitative indicator, which is used to describe the degree to which the optical fiber is damaged or fails due to bending stress. Finally, the optical fiber signal transmission quality is evaluated according to the degree of optical fiber bending stress failure to obtain a signal transmission quality indicator, thereby realizing the analysis and evaluation of quality loss during optical fiber signal transmission, and providing a scientific basis for the maintenance and optimization of optical fiber networks.

[0074] S3. The variational finite element method is used to simulate the non-uniform distribution of the optical fiber refractive index and obtain the variation law of inter-mode energy coupling under different optical fiber bending radii and stress distributions.

[0075] In this embodiment, the step of simulating the non-uniform distribution of the optical fiber refractive index by using the variational finite element method to obtain the variation law of inter-mode energy coupling under different optical fiber bending radii and stress distributions includes:

[0076] The basic refractive index at the attenuation fault point is measured by a Bragg reflection spectrometer, and the optical fiber strain data generated by the optical fiber around the attenuation fault point under the action of bending stress is measured by a strain sensing optical fiber array; the optical fiber strain data includes axial (i.e., optical fiber length direction) strain data and transverse (i.e., perpendicular to the optical fiber length direction) strain data generated by the optical fiber under the action of bending stress;

[0077] According to the optical fiber strain data, the refractive index increment distribution data corresponding to the strain field is obtained by using the elastic-optic effect theory;

[0078] According to the basic refractive index and the refractive index increment distribution data, coupling and solving the stress field of the optical fiber cross section and the refractive index field are performed to obtain the stress distribution of the optical fiber cross section;

[0079] Based on the stress distribution of the optical fiber cross section, the non-uniform distribution of the optical fiber refractive index is simulated using the variational finite element method to obtain the variation law of the mode coupling intensity under different stress distributions;

[0080] According to the variation law of mode coupling intensity under different stress distributions, the recursive least squares method is used to analyze the influence of fiber bending in a two-dimensional plane on the inter-mode energy coupling, and the variation law of inter-mode energy coupling under different fiber bending radii and stress distributions is obtained.

[0081] Specifically, the present embodiment can use a Bragg reflection spectrometer with a working wavelength of 1550 nanometers and a resolution of 0.1 nanometers to accurately measure the refractive index at the attenuation fault point to obtain the basic refractive index. At the same time, a strain sensing optical fiber array with a preset spacing is arranged within a preset range around the attenuation fault point. The strain sensing optical fiber array is used to measure the axial strain data and transverse strain data generated by the bending stress of the optical fiber within a preset range around the attenuation fault point. These data reflect the deformation of the optical fiber under bending stress. According to the collected axial strain data and transverse strain data, combined with the theory of elasto-optic effect, the preset longitudinal elasto-optic coefficient and transverse elasto-optic coefficient are used to calculate the refractive index increment distribution data corresponding to the strain field. This step is based on elasto-optic effect. The optical effect theory converts strain data into refractive index changes to obtain the refractive index increment distribution data corresponding to the strain field. It should be noted that the elastic-optical effect theory describes the phenomenon that the refractive index of a material changes when it is subjected to stress. For an optical fiber, when it is subjected to bending stress (generating axial and lateral strains), its refractive index changes. This embodiment couples and solves the stress field and refractive index field of the optical fiber cross section for the basic refractive index and the refractive index increment distribution data to obtain the stress distribution of the optical fiber cross section. In this embodiment, the steps of coupling and solving the stress field and refractive index field of the optical fiber cross section according to the basic refractive index and the refractive index increment distribution data to obtain the stress distribution of the optical fiber cross section include:

[0082] According to the basic refractive index of the fault point and the refractive index increment distribution data, a tetrahedron mesher is used to perform unstructured meshing on the optical fiber cross section to form an optical fiber core-cladding boundary; wherein the optical fiber core-cladding boundary is a physical boundary between the optical fiber core and the optical fiber cladding defined by the meshing;

[0083] According to the refractive index increment distribution data, the linear relationship between the optical fiber stress and the refractive index increment is analyzed to obtain the refractive index change law of the optical fiber under stress. It should be noted that the photoelastic effect in the optical fiber indicates the birefringence effect of the optical fiber caused by stress, and its principal refractive index is in the same direction as the corresponding principal stress. In terms of numerical value, the change of the refractive index is linearly related to the principal stress.

[0084] The continuity boundary condition of the fiber core-cladding boundary is set, and the stress field and refractive index field of the fiber cross section are coupled and solved based on the law of refractive index change of the fiber under stress to obtain the stress distribution of the fiber cross section; among them, the continuity boundary condition of the fiber core-cladding boundary ensures the continuity of physical quantities at the junction of different media.

[0085] After obtaining the stress distribution of the optical fiber cross section, this embodiment uses the variational finite element method to simulate the non-uniform distribution of the optical fiber refractive index based on the stress distribution of the optical fiber cross section to obtain the variation law of the mode coupling intensity under different stress distributions. The specific steps include:

[0086] The second type of boundary condition of the optical fiber core-cladding boundary is set, and according to the stress distribution of the optical fiber cross section, the variational finite element method is used to simulate the non-uniform distribution of the refractive index of the optical fiber under bending stress, and the refractive index field distribution of the optical fiber cross section is obtained to reveal the non-uniform distribution characteristics of the refractive index of the optical fiber under bending stress;

[0087] According to the refractive index field distribution of the optical fiber cross section, the power coupling coefficient between the fundamental mode and the high-order mode in the optical fiber is calculated by the wave equation, so as to obtain the corresponding relationship between the mode coupling intensity and the stress distribution;

[0088] According to the stress distribution of the optical fiber cross section, the stress distribution law of the optical fiber in radial and circumferential directions is obtained by using the boundary element method;

[0089] According to the corresponding relationship between mode coupling intensity and stress distribution and the stress distribution law of the optical fiber in radial and circumferential directions, the variation law of mode coupling intensity under different stress distributions is obtained.

[0090] Regarding the specific implementation process of the above-mentioned law of mode coupling intensity variation, this embodiment first clarifies the interface conditions between the optical fiber core and the cladding, that is, the second-type boundary conditions (also called Neumann boundary conditions), which describe the relationship between the derivative of the physical quantity on the interface (such as the refractive index gradient) and the physical quantity outside the interface. This embodiment uses numerical modeling software (such as COMSOL, ANSYS, etc.) to establish a geometric model of the optical fiber and set the core-cladding boundary conditions, and then uses the variational finite element method to simulate the non-uniform distribution of the refractive index of the optical fiber under bending stress. Specifically, this embodiment uses the stress distribution of the optical fiber cross section in the bending state as input, and according to the refractive index-stress relationship of the optical fiber material (such as the photoelastic effect), the stress distribution is converted into the refractive index distribution, and the refractive index field distribution of the optical fiber cross section is obtained through numerical solution. The refractive index field distribution of the optical fiber cross section shows the non-uniformity of the refractive index at different positions.

[0091] Then, by solving the wave equation in the optical fiber and calculating the overlap integral between the modes, combined with the refractive index distribution of the optical fiber, numerical methods (such as integration method, matrix method, etc.) are used to calculate the mode coupling coefficient between the fundamental mode and the higher-order mode in the optical fiber, and the power coupling coefficient between the fundamental mode and the higher-order mode of the optical fiber is obtained. The power coupling coefficient between the fundamental mode and the higher-order mode is an important parameter that describes the energy transfer from one mode to another. These coefficients reflect the coupling strength between modes under different stress states, that is, the efficiency or intensity of energy transfer between modes under different stress states. The calculated power coupling coefficient is correlated with the stress distribution data to obtain the corresponding relationship between the mode coupling strength and the stress distribution. Then, considering the stress distribution in the optical fiber cladding, the principles of elastic mechanics are used, combined with the specific structural characteristics of the optical fiber. A stress distribution model is established, and stress analysis methods such as the boundary element method are used to calculate the stress distribution law of the optical fiber in the radial and circumferential directions. The boundary element method is a numerical method based on the boundary integral equation. In the optical fiber stress analysis, the stress distribution can be solved by arranging a series of boundary elements on the boundary of the optical fiber cross section. Then, this embodiment combines the correspondence between the mode coupling intensity and the stress distribution with the stress distribution law of the optical fiber in the radial and circumferential directions. Through data fitting or numerical analysis methods, a comprehensive analysis is made on how the stress distribution affects the energy coupling between modes, and the correspondence between the mode coupling intensity and the stress distribution is established. The change law of the mode coupling intensity under different stress distributions is obtained. The change law of the energy coupling between modes refers to the energy transfer or coupling phenomenon between different modes in the optical fiber due to factors such as stress and temperature changes.

[0092] After obtaining the variation law of mode coupling intensity, this embodiment uses the recursive least squares method to iteratively process the variation law of mode coupling intensity under different stress distributions according to the variation law of mode coupling intensity under different stress distributions. In each iteration, the weight vector and the covariance matrix are updated according to the current estimated error, and the variation curve of the optical fiber bending radius and the mode coupling intensity in the two-dimensional plane is fitted to quantify the influence of the optical fiber bending on the energy coupling between modes. Based on the above fitting results, the variation law of the energy coupling between modes under different optical fiber bending radii and stress distributions is obtained.

[0093] S4. Based on the inter-mode energy coupling variation law and the signal transmission quality index, dynamic power pre-compensation is performed on the optical fiber link quality to obtain the optical power compensation amount required for each attenuation fault point.

[0094] In this embodiment, the step of performing dynamic power pre-compensation on the optical fiber link quality based on the inter-mode energy coupling variation law and the signal transmission quality index to obtain the optical power compensation amount required for each attenuation fault point includes:

[0095] Using an optical fiber temperature sensor array to collect ambient temperature data at the attenuation fault point, and performing temperature compensation on the stress distribution of the optical fiber cross section according to the ambient temperature data to obtain an optical fiber stress correction distribution diagram;

[0096] According to the optical fiber stress correction distribution diagram, the optical fiber stress loss value is calculated by using the inter-mode energy coupling variation law;

[0097] According to the ambient temperature data, the temperature transmission loss value caused by temperature is converted by the temperature refractive index coefficient of the optical fiber material, and the optical fiber stress loss value and the temperature transmission loss value are superimposed by a random forest regressor to obtain the total transmission loss of the optical fiber link;

[0098] According to the total transmission loss of the optical fiber link and the signal transmission quality index, a long short-term memory neural network is used to predict the optical power attenuation trend;

[0099] According to the optical power attenuation trend and a predetermined target optical power value, an optical power compensation amount required for each attenuation fault point is obtained.

[0100] Specifically, in this embodiment, a series of optical fiber temperature sensors are arranged at each key position (such as joints, bends, etc.) on the optical fiber link to form an optical fiber temperature sensor array, and the ambient temperature data at each attenuation fault point in the optical fiber link is collected in real time through the optical fiber temperature sensor array with a sampling frequency of 100 Hz and a measurement accuracy of 0.1 degrees Celsius. Based on the ambient temperature data, the thermal expansion coefficient and stress-temperature relationship of the optical fiber material are used to perform temperature compensation on the stress distribution of the optical fiber cross section to eliminate the influence of temperature changes on the stress distribution of the optical fiber, thereby obtaining a more accurate optical fiber stress correction distribution map. Since the stress in the optical fiber will cause the energy coupling between modes to change, thereby affecting the transmission of the optical signal, therefore, in this embodiment, with respect to the optical fiber stress correction distribution map, the law of energy coupling change between modes is used to calculate the optical fiber stress loss value caused by stress at each attenuation fault point of the optical fiber. The optical fiber stress loss value is a value that describes the optical signal caused by stress in the optical fiber. The optical fiber material is a quantitative indicator of the loss. At the same time, the refractive index of the optical fiber material will change with the change of temperature, thereby affecting the transmission of the optical signal. In this embodiment, the temperature transmission loss value caused by the temperature is converted by using the known temperature refractive index coefficient of the optical fiber material. The optical fiber stress loss value and the temperature transmission loss value are numerically superimposed by a random forest regressor with an input feature dimension of 32 and a tree depth of 16 to obtain the total transmission loss of the optical fiber link. According to the total transmission loss of the optical fiber link and the signal transmission quality indicator, a long short-term memory neural network (LSTM) is used to predict the optical power attenuation trend of each attenuation fault point in the future period of time. The optical power compensation amount required for each attenuation fault point is calculated in combination with the predetermined target optical power value to be achieved in the optical fiber link. The calculated optical power compensation amount is applied to the corresponding position in the optical fiber link to dynamically adjust the optical power to ensure that the signal transmission quality in the optical fiber link meets the requirements and ensure the stable transmission of the optical fiber link.

[0101] S5. Connecting the master station in the power distribution automation system to the measurement and control terminal of the remote access network via a communication link, and performing compensation control on the communication link according to the optical power compensation amount.

[0102] In this embodiment, the step of performing compensation control on the communication link according to the optical power compensation amount includes:

[0103] According to the optical power compensation amount, the communication link is compensated by an optical power equalizer, and the backup optical path switching is started when the communication is interrupted.

[0104] This embodiment realizes optical power compensation control of the communication link between the master station and the measurement and control terminal of the remote access network in the distribution automation system through dynamic adjustment of the optical power equalizer and the laser driving current. When the optical power attenuation or interruption occurs in the communication link, the backup optical path switching can be quickly started to ensure the continuity and stability of the communication. Specifically, this embodiment compensates the communication link according to the optical power compensation amount through the optical power equalizer. The optical power equalizer can adjust the attenuation degree of the optical signal as needed, thereby realizing precise control of the optical power. The optical power compensation amount is converted into the corresponding laser driving current increment through the power adjustment calibration curve. The power adjustment calibration curve can be obtained in advance through experiments, which describes the corresponding relationship between the optical power compensation amount and the laser driving current increment. According to the mapping relationship between the laser driving current increment and the transmission power, a power closed-loop controller with a response time of 0.1 milliseconds is used to adjust the laser injection current in real time. The power closed-loop controller can monitor the working status of the laser in real time and adjust its driving current as needed, so as to achieve precise control of the transmission power. The optical power value of the receiving end is collected again through the optical power monitor, and the collected optical power value is compared with the preset threshold (such as 5 decibels). If there is a deviation, the proportional integral controller is used to dynamically update the transmission optical power. The proportional integral controller can quickly adjust the transmission optical power according to the size and direction of the deviation, so as to achieve adaptive compensation of the optical power. When the communication link is interrupted or severely attenuated, the system can automatically detect this situation, and then start the backup optical path switching mechanism to switch the communication link to the backup optical path. The backup optical path is pre-set to provide an alternative communication path when the main link fails. By switching the backup optical path, the reliability and stability of the communication link between the master station and the measurement and control terminal of the remote access network in the distribution automation system can be effectively improved.

[0105] An embodiment of the present invention provides a distribution network communication method based on a remote access network. The method performs fault detection on an optical fiber link according to the attenuation characteristics of an optical fiber transmission link in a distribution automation system, and identifies attenuation fault points caused by optical fiber bending stress; performs optical fiber signal transmission quality evaluation based on the fault characteristics at the attenuation fault point to obtain a signal transmission quality index; uses a variational finite element method to simulate the non-uniform distribution of the optical fiber refractive index to obtain a law of energy coupling variation between modes under different optical fiber bending radii and stress distributions; performs dynamic power pre-compensation on the optical fiber link quality based on the law of energy coupling variation between modes and the signal transmission quality index to obtain the optical power compensation amount required for each attenuation fault point; connects a master station in the distribution automation system with a measurement and control terminal of a remote access network through a communication link, and performs compensation control on the communication link according to the optical power compensation amount. Compared with the existing technology, this method is based on the analysis of the mode coupling phenomenon generated by the optical fiber under bending stress, introduces dynamic power pre-compensation technology to monitor the quality of the optical fiber communication link in real time, and dynamically adjusts the transmission power according to the link attenuation characteristics, so that the system can quickly respond to changes in the link status, ensuring the continuity and stability of the communication link between the master station and the measurement and control terminal of the remote access network in the distribution automation system, reducing the system cost, and thus effectively improving the reliability and efficiency of the entire distribution network communication system.

[0106] It should be noted that the size of the serial numbers of the above-mentioned processes does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0107] In one embodiment, Figure 2 As shown, an embodiment of the present invention provides a distribution network communication system based on a remote access network, the system comprising:

[0108] The fault identification module 101 is used to detect the fault of the optical fiber link according to the attenuation characteristics of the optical fiber transmission link in the power distribution automation system, and identify the attenuation fault point caused by the bending stress of the optical fiber;

[0109] A signal evaluation module 102, configured to evaluate the optical fiber signal transmission quality according to the fault characteristics at the attenuation fault point to obtain a signal transmission quality index;

[0110] The coupling analysis module 103 is used to simulate the non-uniform distribution of the optical fiber refractive index using the variational finite element method to obtain the variation law of the energy coupling between modes under different optical fiber bending radii and stress distributions;

[0111] The compensation analysis module 104 is used to perform dynamic power pre-compensation on the optical fiber link quality based on the inter-mode energy coupling variation law and the signal transmission quality index, and obtain the optical power compensation amount required for each attenuation fault point;

[0112] The compensation control module 105 is used to connect the master station in the distribution automation system with the measurement and control terminal of the remote access network through a communication link, and to perform compensation control on the communication link according to the optical power compensation amount.

[0113] For the specific definition of a distribution network communication system based on a remote access network, please refer to the above-mentioned definition of a distribution network communication method based on a remote access network, which will not be repeated here. A person of ordinary skill in the art can appreciate that the various modules and steps described in conjunction with the embodiments disclosed in this application can be implemented in hardware, software, or a combination of both. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0114] An embodiment of the present invention provides a distribution network communication system based on a remote access network, wherein a fault identification module of the system performs fault detection on an optical fiber link according to the attenuation characteristics of the optical fiber transmission link in a distribution automation system, and identifies an attenuation fault point caused by optical fiber bending stress; a signal evaluation module evaluates the optical fiber signal transmission quality according to the fault characteristics at the attenuation fault point, and obtains a signal transmission quality index; a coupling analysis module simulates the non-uniform distribution of the optical fiber refractive index using a variational finite element method, and obtains a law of energy coupling variation between modes under different optical fiber bending radii and stress distributions; a compensation analysis module performs dynamic power pre-compensation on the optical fiber link quality based on the law of energy coupling variation between modes and the signal transmission quality index, and obtains the optical power compensation amount required for each attenuation fault point; a compensation control module connects a master station in the distribution automation system with a measurement and control terminal of a remote access network through a communication link, and performs compensation control on the communication link according to the optical power compensation amount. Compared with the existing technology, this system is based on the analysis of the mode coupling phenomenon generated by the optical fiber under bending stress, and introduces dynamic power pre-compensation technology to monitor the quality of the optical fiber communication link in real time, and dynamically adjusts the transmission power according to the link attenuation characteristics, so that the system can quickly respond to changes in the link status, ensuring the continuity and stability of the communication link between the master station and the measurement and control terminal of the remote access network in the distribution automation system, reducing the system cost, and thus effectively improving the reliability and efficiency of the entire distribution network communication system.

[0115] The above-mentioned embodiments only express several preferred implementation modes of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in the technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be regarded as the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be based on the protection scope of the claims.

Claims

1. A distribution network communication method based on a remote access network, characterized in that: The following steps are involved: According to the attenuation characteristics of the optical fiber transmission link in the distribution automation system, the optical fiber link fault detection is carried out to identify the attenuation fault point caused by the optical fiber bending stress; The optical fiber signal transmission quality is evaluated by using the fault characteristics at the attenuation fault point to obtain a signal transmission quality index; The variational finite element method is used to simulate the non-uniform distribution of the optical fiber refractive index, and the variation law of inter-mode energy coupling under different optical fiber bending radius and stress distribution is obtained; Based on the inter-mode energy coupling variation law and the signal transmission quality index, dynamic power pre-compensation is performed on the optical fiber link quality to obtain the optical power compensation amount required for each attenuation fault point; Connecting a master station in a power distribution automation system to a measurement and control terminal of a remote access network via a communication link, and performing compensation control on the communication link according to the optical power compensation amount; The step of simulating the non-uniform distribution of the optical fiber refractive index by using the variational finite element method to obtain the variation law of energy coupling between modes under different optical fiber bending radii and stress distributions includes: The basic refractive index at the attenuation fault point is measured by using a Bragg reflection spectrometer, and the optical fiber strain data generated by the optical fiber around the attenuation fault point under the action of bending stress is measured by using a strain sensing optical fiber array; According to the optical fiber strain data, the refractive index increment distribution data corresponding to the strain field is obtained by using the elastic-optic effect theory; According to the basic refractive index and the refractive index increment distribution data, coupling and solving the stress field of the optical fiber cross section and the refractive index field are performed to obtain the stress distribution of the optical fiber cross section; Based on the stress distribution of the optical fiber cross section, the non-uniform distribution of the optical fiber refractive index is simulated using the variational finite element method to obtain the variation law of the mode coupling intensity under different stress distributions; According to the variation law of mode coupling intensity under different stress distributions, the recursive least squares method is used to analyze the influence of fiber bending in a two-dimensional plane on the inter-mode energy coupling, and the variation law of inter-mode energy coupling under different fiber bending radii and stress distributions is obtained.

2. A distribution network communication method based on a remote access network as claimed in claim 1, characterized in that: The step of performing fault detection on the optical fiber link according to the attenuation characteristics of the optical fiber transmission link in the power distribution automation system and identifying the attenuation fault point caused by the optical fiber bending stress comprises: Collecting reflected signal waveform data in the optical fiber link in the power distribution automation system, and using a median filter to eliminate baseline noise on the reflected signal waveform data to obtain a reflected signal baseline curve; According to the reflected signal baseline curve, dispersion compensation processing is performed on the reflected signal waveform data by using a preset dispersion compensation coefficient to obtain compensated waveform data; Performing noise reduction filtering on the compensation waveform data using a multi-scale wavelet decomposition algorithm to obtain a filtered reflection signal; Extracting attenuation feature points in the optical fiber link according to the filtered reflection signal and a preset attenuation feature recognition threshold; Optical frequency domain reflection technology is used to measure the forward and reverse reflection waveforms of the attenuation characteristic points to locate and identify the attenuation fault points caused by optical fiber bending stress.

3. A distribution network communication method based on a remote access network as claimed in claim 1, characterized in that: The step of evaluating the optical fiber signal transmission quality by using the fault characteristics at the attenuation fault point to obtain the signal transmission quality index comprises: Establishing an attenuation point characteristic curve according to the fault characteristics at the attenuation fault point, and establishing a stress attenuation characteristic library using optical fiber microbending theory; Performing an attenuation pattern matching operation on the attenuation point characteristic curve and the stress attenuation characteristic library to obtain a pattern matching result; According to the mode matching result and the optical fiber microbending loss theory, the attenuation of the attenuation fault point is calculated; Based on the attenuation of the attenuation fault point, a convolutional neural network is used to analyze the optical fiber stress distribution at the attenuation fault point to quantify the degree of optical fiber bending stress fault; The optical fiber signal transmission quality is evaluated according to the degree of the optical fiber bending stress failure to obtain a signal transmission quality index.

4. A distribution network communication method based on a remote access network as claimed in claim 1, characterized in that: The step of coupling and solving the stress field and the refractive index field of the optical fiber cross section according to the basic refractive index and the refractive index increment distribution data to obtain the stress distribution of the optical fiber cross section comprises: According to the basic refractive index of the attenuation fault point and the refractive index increment distribution data, a tetrahedral mesher is used to perform unstructured meshing on the optical fiber cross section to form an optical fiber core-cladding boundary; Analyze the linear relationship between optical fiber stress and refractive index increment according to the refractive index increment distribution data to obtain the refractive index change law of the optical fiber under stress; The continuity boundary condition of the fiber core-cladding boundary is set, and the stress field and refractive index field of the fiber cross section are coupled and solved based on the law of refractive index change of the fiber under stress to obtain the stress distribution of the fiber cross section.

5. A distribution network communication method based on a remote access network as claimed in claim 1, characterized in that: The step of simulating the non-uniform distribution of the optical fiber refractive index by using the variational finite element method based on the stress distribution of the optical fiber cross section to obtain the variation law of the mode coupling intensity under different stress distributions includes: According to the stress distribution of the optical fiber cross section, the non-uniform distribution of the refractive index of the optical fiber under bending stress is simulated by using the variational finite element method to obtain the refractive index field distribution of the optical fiber cross section; Calculating the power coupling coefficient between the fundamental mode and the high-order mode in the optical fiber by using a wave equation according to the refractive index field distribution of the optical fiber cross section; According to the stress distribution of the optical fiber cross section, the stress distribution law of the optical fiber in radial and circumferential directions is obtained by using the boundary element method; According to the power coupling coefficient and the stress distribution law of the optical fiber in the radial direction and the circumferential direction, the variation law of the mode coupling intensity under different stress distributions is obtained.

6. A distribution network communication method based on a remote access network as claimed in claim 1, characterized in that: The optical fiber strain data includes axial strain data and transverse strain data generated by the optical fiber under the action of bending stress.

7. A distribution network communication method based on a remote access network as claimed in claim 1, characterized in that: The step of performing dynamic power pre-compensation on the optical fiber link quality based on the inter-mode energy coupling variation law and the signal transmission quality index to obtain the optical power compensation amount required for each attenuation fault point comprises: Using an optical fiber temperature sensor array to collect ambient temperature data at the attenuation fault point, and performing temperature compensation on the stress distribution of the optical fiber cross section according to the ambient temperature data to obtain an optical fiber stress correction distribution diagram; According to the optical fiber stress correction distribution diagram, the optical fiber stress loss value is calculated by using the inter-mode energy coupling variation law; According to the ambient temperature data, the temperature transmission loss value caused by temperature is converted by the temperature refractive index coefficient of the optical fiber material, and the optical fiber stress loss value and the temperature transmission loss value are superimposed by a random forest regressor to obtain the total transmission loss of the optical fiber link; According to the total transmission loss of the optical fiber link and the signal transmission quality index, a long short-term memory neural network is used to predict the optical power attenuation trend; According to the optical power attenuation trend and a predetermined target optical power value, an optical power compensation amount required for each attenuation fault point is obtained.

8. A distribution network communication method based on a remote access network as claimed in claim 1, characterized in that: The step of performing compensation control on the communication link according to the optical power compensation amount comprises: According to the optical power compensation amount, the communication link is compensated by an optical power equalizer, and the backup optical path switching is started when the communication is interrupted.

9. A distribution network communication system based on a remote access network, characterized in that: The system comprises: A fault identification module is used to detect faults in optical fiber links according to the attenuation characteristics of optical fiber transmission links in the power distribution automation system, and to identify attenuation fault points caused by optical fiber bending stress; A signal evaluation module, used to evaluate the optical fiber signal transmission quality according to the fault characteristics at the attenuation fault point to obtain a signal transmission quality index; The coupling analysis module is used to simulate the non-uniform distribution of the optical fiber refractive index using the variational finite element method to obtain the variation law of inter-mode energy coupling under different optical fiber bending radii and stress distributions; A compensation analysis module, used to perform dynamic power pre-compensation on the optical fiber link quality based on the inter-mode energy coupling variation law and the signal transmission quality index, and obtain the optical power compensation amount required for each attenuation fault point; A compensation control module, used to connect the master station in the power distribution automation system with the measurement and control terminal of the remote access network through a communication link, and to perform compensation control on the communication link according to the optical power compensation amount; Wherein, the coupling analysis module is specifically used for: The basic refractive index at the attenuation fault point is measured by using a Bragg reflection spectrometer, and the optical fiber strain data generated by the optical fiber around the attenuation fault point under the action of bending stress is measured by using a strain sensing optical fiber array; According to the optical fiber strain data, the refractive index increment distribution data corresponding to the strain field is obtained by using the elastic-optic effect theory; According to the basic refractive index and the refractive index increment distribution data, coupling and solving the stress field of the optical fiber cross section and the refractive index field are performed to obtain the stress distribution of the optical fiber cross section; Based on the stress distribution of the optical fiber cross section, the non-uniform distribution of the optical fiber refractive index is simulated using the variational finite element method to obtain the variation law of the mode coupling intensity under different stress distributions; According to the variation law of mode coupling intensity under different stress distributions, the recursive least squares method is used to analyze the influence of fiber bending in a two-dimensional plane on the inter-mode energy coupling, and the variation law of inter-mode energy coupling under different fiber bending radii and stress distributions is obtained.

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