Frequency spectrum monitoring and interference analysis method for power grid wireless communication

Abstract

The invention discloses a frequency spectrum monitoring and interference analysis method for power grid wireless communication, and particularly relates to the technical field of wireless frequency spectrum monitoring. Outputting an eddy current distribution parameter set based on the power frequency magnetic field intensity distribution data of the monitoring point; synchronously acquiring a frequency spectrum signal and a power frequency magnetic flux density signal; calculating high-frequency harmonic frequency point characteristics of secondary radiation generated by the frequency spectrum monitoring equipment in the power frequency magnetic field, and generating an eddy current characteristic spectral line graph; extracting a frequency band energy value matched with the eddy current characteristic spectral line diagram in the frequency spectrum signal, and calculating a pollution proportion of secondary radiation to the frequency spectrum signal in combination with the power frequency magnetic flux density signal; eliminating pollution signal components according to the pollution proportion, and outputting a real spectrum; and performing joint scanning on the real frequency spectrum, extracting modulation characteristics and spatial orientation of the residual interference signal, and generating an interference source positioning report. The problem of real spectrum signal distortion caused by eddy current secondary radiation in a power frequency magnetic field environment is solved, and the accuracy and reliability of spectrum monitoring and interference analysis are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless spectrum monitoring. More specifically, the present invention relates to a spectrum monitoring and interference analysis method for power grid wireless communication. Background Art

[0002] In the current spectrum monitoring of power grid wireless communication, especially when deploying monitoring equipment in power frequency magnetic field environments such as high-voltage substations, the spectrum measurement results often have authenticity deviations.

[0003] The existing technologies mainly focus on the extraction of external source characteristics of environmental electromagnetic interference, ignoring the induced response problems of the spectrum monitoring equipment itself in the power frequency alternating magnetic field, especially the eddy current effect formed by the equipment structure under the action of a strong magnetic field, which seriously affects the accurate reconstruction of the actual electromagnetic environment and the identification of interference sources.

[0004] To solve the above problems, a technical solution is provided. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a spectrum monitoring and interference analysis method for power grid wireless communication to solve the problems raised in the above background art.

[0006] To achieve the above object, the present invention provides the following technical solutions: A spectrum monitoring and interference analysis method for power grid wireless communication, comprising the following steps: S1: Based on the power frequency magnetic field intensity distribution data of the monitoring point, establish an eddy current distribution model of the spectrum monitoring equipment, and output an eddy current distribution parameter set induced by the power frequency magnetic field; S2: Collect the spectrum signal of the radio frequency receiving channel of the spectrum monitoring equipment and the power frequency magnetic flux density signal of the magnetic field sensing channel, and align the sampling points through a phase synchronization algorithm; S3: According to the eddy current distribution parameter set, calculate the high-frequency harmonic frequency point characteristics of the secondary radiation generated by the spectrum monitoring equipment under the power frequency magnetic field, and generate an eddy current characteristic spectrogram; S4: Based on the spectrum signal, extract the band energy value matching the eddy current characteristic spectrogram, and combine it with the power frequency magnetic flux density signal to calculate the pollution ratio of the secondary radiation generated by the spectrum monitoring equipment under the power frequency magnetic field to the spectrum signal; S5: Based on the pollution ratio, eliminate the pollution signal component in the spectrum signal, and output the purified real environment spectrum; S6: Perform a time-frequency joint scan on the purified real environment spectrum, detect the modulation characteristics and spatial orientation of the residual interference signal, and generate a power grid wireless communication interference source positioning report.

[0007] In a preferred embodiment, S1 is specifically: Collect the power frequency magnetic field intensity distribution data at the monitoring point where the spectrum monitoring device is installed in the high-voltage substation. According to the structural parameter information of the spectrum monitoring device in the high-voltage substation and combined with the power frequency magnetic field intensity distribution data, establish an eddy current distribution model of the spectrum monitoring device under the action of the power frequency magnetic field. By analytically solving the electromagnetic induction equation, obtain the eddy current distribution parameter set of the spectrum monitoring device in the power frequency magnetic field environment.

[0008] In a preferred embodiment, S2 is specifically as follows: Collect the spectrum signals in the radio frequency receiving channel of the spectrum monitoring device in the high-voltage substation. Collect the power frequency magnetic flux density signals in the magnetic field sensing channel of the spectrum monitoring device in the high-voltage substation. Adopt a phase synchronization algorithm based on the time synchronization reference signal to synchronize the spectrum signals collected by the radio frequency receiving channel of the spectrum monitoring device and the power frequency magnetic flux density signals collected by the magnetic field sensing channel, and align the sampling points of the spectrum signals and the power frequency magnetic flux density signals.

[0009] In a preferred embodiment, S3 is specifically as follows: According to the eddy current distribution parameter set and combined with the structural parameters of the spectrum monitoring device in the high-voltage substation, calculate the high-frequency harmonic frequency point characteristics generated by the spectrum monitoring device under the action of the power frequency magnetic field through the electromagnetic secondary radiation calculation model; the high-frequency harmonic frequency point characteristics include the high-frequency harmonic frequency value and the corresponding radiation amplitude value. Based on the Fourier transform and spectrum analysis methods, generate an eddy current characteristic spectral line diagram reflecting the high-frequency harmonic frequency point characteristics; the abscissa of the eddy current characteristic spectral line diagram represents the harmonic frequency, and the ordinate represents the electromagnetic radiation amplitude value corresponding to the harmonic frequency.

[0010] In a preferred embodiment, S4 is specifically as follows: Perform frequency domain processing on the spectrum signals, and according to the high-frequency harmonic frequency point characteristics of the eddy current characteristic spectral line diagram, identify the band energy values corresponding to the eddy current characteristic spectral line diagram in the spectrum signals. Calculate the change rate of the power frequency magnetic flux density of the power frequency magnetic flux density signal in the magnetic field sensing channel. Based on the band energy value and the change rate of the power frequency magnetic flux density, calculate the pollution ratio of the eddy current secondary radiation generated by the spectrum monitoring device under the action of the power frequency magnetic field to the spectrum signals.

[0011] In a preferred embodiment, S5 is specifically as follows: According to the pollution ratio of the eddy current secondary radiation generated by the spectrum monitoring device under the action of the power frequency magnetic field to the spectrum signals, identify the signal components contaminated by the eddy current secondary radiation corresponding to the eddy current characteristic spectral line diagram in the spectrum signals. Based on the spectrum filtering processing method, the signal components contaminated by the secondary radiation of eddy currents are removed from the spectrum signal; The spectrum signal after removing the signal components contaminated by the secondary radiation of eddy currents is used as the purified real environment spectrum.

[0012] In a preferred embodiment, S6 is specifically as follows: Perform joint time-domain and frequency-domain scanning processing on the purified real environment spectrum to obtain the residual interference signals in the real environment spectrum; Adopt modulation recognition to extract the characteristic parameters of the residual interference signals in the real environment spectrum; Adopt the spatial spectrum estimation method, combined with the spatial coordinates of the spectrum monitoring equipment in the high-voltage substation, to determine the spatial orientation of the residual interference signals; Integrate the characteristic parameters and spatial azimuth angles of the residual interference signals to form a positioning report of the power grid wireless communication interference source.

[0013] The technical effects and advantages of a spectrum monitoring and interference analysis method for power grid wireless communication according to the present invention: Establish an eddy current distribution model based on the power frequency magnetic field intensity distribution data to realize quantitative modeling of the eddy current induction behavior of spectrum monitoring equipment in a high-intensity magnetic field environment, and improve the controllability of the interference source of the spectrum monitoring equipment body; by collecting spectrum signals and power frequency magnetic flux density signals and performing phase synchronization processing, ensure the timing consistency of multi-source data, and provide a time reference for interference tracing; calculate the high-frequency harmonic frequency point characteristics based on the eddy current distribution parameter set and generate an eddy current characteristic spectrum diagram, which helps to accurately describe the secondary radiation interference characteristics of spectrum monitoring equipment; match the spectrum signal with the eddy current characteristic spectrum diagram, and combine the power frequency magnetic flux density signal to quantify the pollution ratio, and effectively separate the non-linear distortion introduced by the spectrum monitoring equipment itself; use the pollution ratio to remove the contaminated signal components, and improve the authenticity and usability of spectrum data; perform residual interference recognition and spatial positioning on the purified real environment spectrum to enhance the ability to track interference sources in the power grid environment. Effectively solve the problem of equipment induction interference caused by power frequency magnetic fields in high-voltage substations, and improve the reconstruction accuracy of the real electromagnetic environment and the positioning accuracy of interference sources. Brief Description of the Drawings

[0014] Figure 1 It is a schematic diagram of a spectrum monitoring and interference analysis method for power grid wireless communication according to the present invention. Detailed Embodiments

[0015] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0016] Embodiment Figure 1 A spectrum monitoring and interference analysis method for power grid wireless communication according to the present invention is provided, which includes the following steps: S1: Based on the power frequency magnetic field intensity distribution data of the monitoring point, establish an eddy current distribution model of the spectrum monitoring device, and output an eddy current distribution parameter set induced by the power frequency magnetic field; S2: Collect the spectrum signals of the radio frequency receiving channel of the spectrum monitoring device and the power frequency magnetic flux density signals of the magnetic field sensing channel, and align the sampling points through a phase synchronization algorithm; S3: According to the eddy current distribution parameter set, calculate the high-frequency harmonic frequency point characteristics of the secondary radiation generated by the spectrum monitoring device under the power frequency magnetic field, and generate an eddy current characteristic spectrogram; S4: Extract the band energy value matching the eddy current characteristic spectrogram based on the spectrum signal, and combine it with the power frequency magnetic flux density signal to calculate the pollution ratio of the secondary radiation generated by the spectrum monitoring device under the power frequency magnetic field to the spectrum signal; S5: Based on the pollution ratio, eliminate the polluted signal components in the spectrum signal, and output the purified real environment spectrum; S6: Perform a time-frequency joint scan on the purified real environment spectrum, detect the modulation characteristics and spatial orientation of the residual interference signal, and generate a power grid wireless communication interference source location report.

[0017] S1: Based on the power frequency magnetic field intensity distribution data of the monitoring point, establish an eddy current distribution model of the spectrum monitoring device, and output an eddy current distribution parameter set induced by the power frequency magnetic field, including: Collect the power frequency magnetic field intensity distribution data of the monitoring point where the spectrum monitoring device is installed in the high-voltage substation; The spectrum monitoring device is deployed in the high-voltage substation environment, and the high-voltage substation includes various devices such as transformers, high-voltage switches, busbars, and supporting structural brackets and metal grounding devices. Due to the existence of power frequency current in the high-voltage substation, when the power frequency current flows in the busbars, conductors, and devices, it will generate an obvious power frequency magnetic field intensity distribution inside the substation. The power frequency magnetic field intensity distribution data describes the strength characteristics of the magnetic field at each point in the three-dimensional space of the substation.

[0018] Spatial lattice measurement is carried out using a magnetic field measurement instrument. Specifically, a power frequency magnetic field measurement instrument is selected, and the measurement principle is to measure the power frequency magnetic field intensity by using the magnitude of the induced electromotive force in the coil of the magnetic field sensing device. During the measurement process, the magnetic field measurement instrument is arranged in the surrounding space area of the deployment position of the spectrum monitoring device. Taking the position of the spectrum monitoring device as the center, a spatial measurement grid is constructed. The spatial measurement grid is in the shape of a regular cube, and the measurement positions are arranged with a uniformly spaced measurement lattice. The spatial coordinates of each measurement position are measured and determined by a laser rangefinder, and the spatial coordinate information of each measurement position is recorded. The spatial coordinate information includes the values in the vertical direction, height direction, and depth direction.

[0019] After determining the measurement positions, the power frequency magnetic field intensity is measured one by one for each measurement position in the spatial measurement grid. At each measurement position, the magnetic field measurement instrument measures the induced electromotive force generated by the power frequency magnetic field through the built-in electromagnetic induction coil, and calculates the magnetic field intensity value of the power frequency magnetic field at the measurement position according to the induced electromotive force. The calculation formula for the magnetic field intensity is: the magnetic field intensity is equal to the induced electromotive force divided by the product of the area of the coil of the magnetic field measurement instrument and the power frequency. The measurement process is repeated successively for all measurement positions in the spatial measurement grid, and the magnetic field intensity values at each measurement position are recorded one by one to form a three-dimensional spatial power frequency magnetic field intensity distribution data set.

[0020] The power frequency magnetic field intensity distribution data set obtained from the measurement is preprocessed, including denoising and smoothing processing, to eliminate abnormal values caused by external interference or instrument precision errors during the measurement process. The smoothing processing uses a spatial data interpolation method, selects the Kriging interpolation algorithm, and optimizes the smoothness of the power frequency magnetic field intensity data by considering the spatial correlation of the magnetic field intensity between measurement points and the continuity of the numerical distribution, generating a continuous and smooth power frequency magnetic field intensity distribution data field.

[0021] According to the structural parameter information of the spectrum monitoring device in the high-voltage substation and combining with the power frequency magnetic field intensity distribution data, an eddy current distribution model of the spectrum monitoring device under the action of the power frequency magnetic field is established; Construct an eddy current distribution model of the spectrum monitoring device in the power frequency magnetic field environment of the high-voltage substation. Specifically for the eddy current distribution model. First, obtain the structural parameter information of the spectrum monitoring device, including the metal shell size parameters, material conductivity parameters, spatial installation position parameters, structural geometry parameters, etc. of the spectrum monitoring device. The structural parameter information is obtained through the structural design drawings of the spectrum monitoring device and the technical manuals of the materials of the spectrum monitoring device. Using electromagnetic simulation software, an electromagnetic finite element simulation model of the structure of the spectrum monitoring device is established according to the structural parameter information of the spectrum monitoring device.

[0022] In the electromagnetic finite element simulation model, the power frequency magnetic field intensity distribution data field is imported and applied as the input boundary condition to the electromagnetic finite element simulation model of the spectrum monitoring device. The electromagnetic simulation software uses the finite element algorithm to discretize the structure of the spectrum monitoring device into multiple elements and solve the Maxwell equations in the electromagnetic field equations for each element, including the relationship expressions between the electric field intensity and the magnetic field intensity, the eddy current density and the conductivity, and the frequency. The eddy current density distribution values of all elements are obtained by finite element iterative solution. By integrating the eddy current density distribution values in all elements, the eddy current distribution characteristics on the surface of the entire spectrum monitoring device are obtained.

[0023] By analytically solving the electromagnetic induction equation, a set of eddy current distribution parameters of the spectrum monitoring device in the power frequency magnetic field environment is obtained; Based on the eddy current distribution characteristics on the surface of the spectrum monitoring device, the eddy current distribution parameters are refined by analytically solving the electromagnetic induction equation. The analytical solution steps of the electromagnetic induction equation are as follows: according to the eddy current density characteristic distribution on the surface of the spectrum monitoring device, the electromagnetic induction law is applied to calculate the induced electromotive force generated by the eddy current in each element and the eddy current distribution, determine the eddy current path and the distribution characteristics of the current density amplitude and phase. The analytical solution method of the electromagnetic induction equation is to expand the integral term in the electromagnetic induction equation and solve the eddy current distribution of each element according to the conductivity, permeability and magnetic field frequency analytical expressions of the metal structure of the spectrum monitoring device.

[0024] Integrate the eddy current density, amplitude, phase and spatial position data calculated by the analytical solution of all elements to form a complete set of eddy current distribution parameters of the spectrum monitoring device in the power frequency magnetic field environment. The eddy current distribution parameter set includes the intensity distribution, direction distribution and phase distribution characteristics of the eddy current at each position on the surface of the spectrum monitoring device structure, providing data support for analyzing the secondary radiation interference spectrum of the spectrum monitoring device caused by eddy currents.

[0025] S2: Collect the spectrum signal of the radio frequency receiving channel and the power frequency magnetic flux density signal of the magnetic field sensing channel of the spectrum monitoring device, and align the sampling points through the phase synchronization algorithm, including: Collect the spectrum signal in the radio frequency receiving channel of the spectrum monitoring device in the high-voltage substation; The spectrum monitoring device includes two independent data acquisition channels, namely the radio frequency receiving channel and the magnetic field sensing channel. The radio frequency receiving channel is used to receive the wireless spectrum signals generated by the secondary radiation of the power frequency magnetic field and the environmental signals in the space of the high-voltage substation; the magnetic field sensing channel is used to collect the power frequency magnetic flux density signals at specific monitoring positions in the high-voltage substation in real time.

[0026] In the RF receiving channel of the spectrum monitoring device, a broadband RF receiving device is used to continuously and real-time collect wireless electromagnetic signals in the substation environment. The broadband RF receiving device includes a high-frequency receiving antenna, an RF low-noise amplifier, an intermediate-frequency filter, and a high-precision analog-to-digital conversion device. The high-frequency receiving antenna is a broadband omnidirectional antenna for capturing RF signals in all directions; the gain of the RF low-noise amplifier is designed and optimized to ensure that the signal amplification factor is stable and the signal-to-noise ratio remains within an effective range; the intermediate-frequency filter adopts a band-pass structure to limit the frequency range of the received signal and filter out stray signals outside the frequency range; the high-precision analog-to-digital conversion device provides a high-resolution digital signal output.

[0027] The RF receiving channel feeds the received analog RF signal to the RF low-noise amplifier through the antenna for preliminary signal amplification, and then filters it through the band-pass intermediate-frequency filter. The filtered intermediate-frequency signal is transmitted to the high-precision analog-to-digital conversion device to complete the conversion process from analog signal to digital signal and form a spectrum signal data stream. The entire acquisition process is carried out continuously without interruption to ensure that the spectrum data accurately reflects the real electromagnetic conditions in the substation environment in real time.

[0028] Collect the power-frequency magnetic flux density signal in the magnetic field sensing channel of the spectrum monitoring device in the high-voltage substation; In the magnetic field sensing channel, the magnetic field sensor uses a high-precision Hall effect magnetic flux density sensor, which can accurately capture in real time the magnetic flux density signal generated by the change of the power-frequency magnetic field at the monitoring position in the substation. The magnetic field sensor is fixedly installed at a specified position near the spectrum monitoring device to accurately monitor the real-time change of the magnetic flux density at the specified position.

[0029] The power-frequency magnetic flux density signal collected by the magnetic field sensing channel is real-time converted into a digital data stream through a high-precision analog-to-digital conversion device. The conversion device used in the conversion process has the same high sampling accuracy and frequency as the RF receiving channel to ensure the accuracy unity of the two data streams during the synchronization process. The collected magnetic flux density data is continuous and high-resolution time-series data, which completely records the detailed information of the magnetic field strength changing with time.

[0030] Adopt a phase synchronization algorithm based on the time synchronization reference signal to synchronize the spectrum signal collected by the RF receiving channel of the spectrum monitoring device and the power-frequency magnetic flux density signal collected by the magnetic field sensing channel, and align the sampling points of the spectrum signal and the power-frequency magnetic flux density signal; To achieve effective synchronization of the signals collected by the above two channels, a phase synchronization algorithm based on the time synchronization reference signal is adopted. The time synchronization reference signal is simultaneously sent into the RF receiving channel and the magnetic field sensing channel as the common clock reference for the two channels to ensure that the clock references of the collected data are exactly the same.

[0031] When implementing the phase synchronization algorithm, first select a standard synchronous clock pulse signal as the synchronization reference benchmark. Based on the synchronous clock pulse signal, use the digital phase-locked loop method to achieve the synchronization of the sampling moments of the spectrum signal and the power frequency magnetic flux density signal. Initially collect the sampling points of the spectrum signal data stream and the magnetic flux density signal data stream respectively, and then calculate the phase difference between the sampling signals of the two channels relative to the synchronization reference through the digital phase-locked loop algorithm, and compensate and adjust the phase difference in real time to achieve precise phase alignment between the sampling points of the two signals.

[0032] S3: According to the eddy current distribution parameter set, calculate the high-frequency harmonic frequency point characteristics of the secondary radiation generated by the spectrum monitoring device under the power frequency magnetic field, and generate an eddy current characteristic spectrogram, including: According to the eddy current distribution parameter set, combined with the structural parameters of the spectrum monitoring device in the high-voltage substation, calculate the high-frequency harmonic frequency point characteristics of the spectrum monitoring device generated under the action of the power frequency magnetic field through the electromagnetic secondary radiation calculation model; The electromagnetic secondary radiation calculation model is a frequency-domain finite element analysis model. The frequency-domain finite element analysis model is applicable to the calculation of the electromagnetic secondary radiation characteristics of complex structures.

[0033] Use the eddy current distribution parameter set on the surface of the spectrum monitoring device as the radiation source input, and solve the electromagnetic field radiation characteristics in the frequency domain through Maxwell's equations. The expression form of Maxwell's equations in the frequency domain includes the Helmholtz equation of the spatial distribution relationship between the electric field and the magnetic field strength, and use the structural parameter information and spatial boundary conditions of the spectrum monitoring device to calculate the calculation region and the electromagnetic field constraint conditions. The spatial boundary conditions refer to: when establishing the electromagnetic finite element simulation model and the electromagnetic secondary radiation calculation model of the spectrum monitoring device, the spatial calculation boundary conditions of the environment where the model is located need to be set, including: the range of the simulation calculation region, that is, the size and boundary position of the space around the spectrum monitoring device in the high-voltage substation; the propagation and reflection conditions of electromagnetic waves at the boundary of the simulation region; other structures of the existing high-voltage substation.

[0034] During the calculation, the electromagnetic secondary radiation calculation model discretizes the spectrum monitoring device into a large number of tiny units, applies eddy current parameters to each tiny unit, and connects them through continuous boundary conditions between the tiny units to ensure the continuity and stability of the calculation. The discretization process uses the mesh generation method, and the selection of the mesh element size is based on the radiation frequency range of the spectrum monitoring device to ensure that the mesh element size is smaller than the wavelength of electromagnetic waves in the material, thereby improving the accuracy of the calculation results.

[0035] After the electromagnetic secondary radiation calculation model solves the eddy current distribution parameter set, the high-frequency harmonic frequency point characteristics of the radiation on the surface of the spectrum monitoring device structure under the action of the power frequency magnetic field are obtained. The high-frequency harmonic frequency point characteristics include the high-frequency harmonic frequency value and the corresponding radiation amplitude value. The high-frequency harmonic frequency value is the high-frequency harmonic frequency that is an integer multiple of the power frequency excited by the non-linear effect of the eddy current induced by the power frequency magnetic field. The radiation amplitude value of each harmonic frequency is determined by the calculation result of the electromagnetic field corresponding to the frequency. The amplitude value calculation method is obtained by integrating the amplitude of the spatial electromagnetic field vector field distribution at the specified radiation field point in the model.

[0036] Based on the Fourier transform and spectrum analysis method, an eddy current characteristic spectrogram reflecting the high-frequency harmonic frequency point characteristics is generated; Before performing the Fourier transform, preprocessing is performed on the high-frequency harmonic frequency point characteristics, including data interpolation and smoothing processing. Linear interpolation method is used for data interpolation to supplement the missing values between discrete frequency points that may appear in the calculation. Moving average filtering method is used for smoothing processing to reduce the abnormal mutation points of the amplitude caused by calculation or measurement errors, and ensure that the curve of the generated eddy current characteristic spectrogram is continuous and stable.

[0037] The implementation process of the Fourier transform is to perform a frequency domain transformation on the radiation amplitude value corresponding to the processed high-frequency harmonic frequency value. The transformation process includes the following steps: First, determine the relationship between the electromagnetic field intensity of the spectrum monitoring device at a specific spatial position and the frequency; then input the processed high-frequency harmonic frequency point characteristics into the Fourier transform formula. The Fourier transform formula is: The spectrum amplitude value is equal to the frequency distribution relationship of the amplitude obtained by integrating the processed high-frequency harmonic frequency point characteristics over the entire frequency range. The transformation result is presented in the form of a spectrogram, which is the eddy current characteristic spectrogram. The abscissa of the eddy current characteristic spectrogram represents the harmonic frequency, and the ordinate represents the electromagnetic radiation amplitude value corresponding to the harmonic frequency.

[0038] S4: Extract the band energy value matching the eddy current characteristic spectrogram based on the spectrum signal, and combine it with the power frequency magnetic flux density signal to calculate the pollution ratio of the secondary radiation generated by the spectrum monitoring device under the power frequency magnetic field to the spectrum signal, including: Perform frequency domain processing on the spectrum signal, and identify the band energy value corresponding to the eddy current characteristic spectrogram in the spectrum signal according to the high-frequency harmonic frequency point characteristics of the eddy current characteristic spectrogram; The implementation method of frequency domain processing is the fast Fourier transform algorithm. The fast Fourier transform algorithm includes segment sampling of the spectrum signal data stream. The sampling length is determined in combination with the sampling rate of the spectrum monitoring device to ensure that the resolution of the frequency domain analysis can distinguish the frequency components in the spectrum signal.

[0039] Divide the spectrum signal collected by the radio frequency receiving channel into several segments according to a fixed time duration, and perform fast Fourier transform within each segment. Specifically, the amplitude value of the spectrum signal at each frequency point is obtained by calculating the integral of the spectrum signal multiplied by the Fourier transform basis function within the corresponding time period. The calculated result forms the amplitude distribution curve of the spectrum signal, indicating the specific energy magnitude of each frequency point in the spectrum signal.

[0040] Based on the high-frequency harmonic frequency point characteristics in the eddy current characteristic spectrum diagram, identify the band energy values in the spectrum signal corresponding to the high-frequency harmonic frequency point characteristics of the eddy current characteristic spectrum diagram. Specifically, it is a spectrum matching algorithm. The spectrum matching algorithm multiplies the amplitude distribution curve of the spectrum signal and the eddy current characteristic spectrum diagram point by point and then sums them to determine the degree of correlation between the two, thereby identifying the energy values of the spectrum signal corresponding to each high-frequency harmonic frequency point in the eddy current characteristic spectrum diagram.

[0041] For each harmonic frequency point in the eddy current characteristic spectrum diagram, the spectrum matching algorithm calculates the energy integral of the spectrum signal within the corresponding frequency range respectively. The calculation formula for the band energy value is: the result of integrating the squared amplitude value of the spectrum signal near a specific frequency point within a specific frequency neighborhood interval. The integration frequency range is centered on the frequency point of the eddy current characteristic spectrum diagram and extends a certain frequency interval. All band energy values constitute the set of band energy values in the spectrum signal corresponding to the eddy current characteristic spectrum diagram.

[0042] Calculate the change rate of the power frequency magnetic flux density of the power frequency magnetic flux density signal of the magnetic field sensing channel; Perform the calculation of the change rate of the power frequency magnetic flux density on the power frequency magnetic flux density signal collected by the magnetic field sensing channel. The calculation of the change rate of the power frequency magnetic flux density adopts the time-domain difference method, that is, calculate the ratio of the difference between the power frequency magnetic flux density signals at consecutive time points to the corresponding sampling time interval. The calculation formula is: the change rate of the power frequency magnetic flux density is equal to the difference in the values of the power frequency magnetic flux density signals at adjacent sampling time points divided by the sampling time interval between adjacent sampling time points.

[0043] Based on the band energy value and the change rate of the power frequency magnetic flux density, calculate the pollution ratio of the eddy current secondary radiation generated by the spectrum monitoring device under the action of the power frequency magnetic field on the spectrum signal; The calculation method of the pollution ratio is the regression analysis method, and the multiple linear regression algorithm is selected. The multiple linear regression algorithm can identify the linear dependence relationship between the band energy value of the spectrum signal and the change rate of the power frequency magnetic flux density, thereby calculating the pollution ratio. Specifically: First, a multiple linear regression model is established with the frequency band energy value as the dependent variable and the change rate of power frequency magnetic flux density as the independent variable. The model parameters include the regression coefficient and the intercept. The calculation formula of the model is: the frequency band energy value is equal to the regression coefficient multiplied by the change rate of power frequency magnetic flux density and then added with the intercept. The regression coefficient and the intercept are obtained by solving through the least squares method. The solving process is to minimize the sum of the squared errors between the predicted frequency band energy value of the model and the actual frequency band energy value.

[0044] After obtaining the regression coefficients corresponding to each frequency band through model calculation, the pollution ratio is calculated according to the regression coefficients. The calculation formula of the pollution ratio is: the pollution ratio is equal to the regression coefficient multiplied by the change rate of power frequency magnetic flux density at the corresponding sampling time point and then divided by the actual frequency band energy value.

[0045] S5: Based on the pollution ratio, eliminate the polluted signal components in the spectrum signal and output the purified real - environment spectrum, including: According to the pollution ratio of the spectrum signal caused by the eddy current secondary radiation generated under the action of the power frequency magnetic field on the spectrum monitoring device, identify the signal components contaminated by the eddy current secondary radiation corresponding to the eddy current characteristic spectrum diagram in the spectrum signal; Based on the pollution ratio, use the spectrum energy separation algorithm to identify the polluted signal components in the spectrum signal. The implementation method of the spectrum energy separation algorithm is to multiply the amplitude value corresponding to each frequency band in the amplitude distribution curve of the spectrum signal by the pollution ratio of the frequency band to obtain the amplitude value of the polluted signal components caused by the eddy current secondary radiation in each frequency band.

[0046] Based on the spectrum filtering processing method, remove the signal components contaminated by the eddy current secondary radiation from the spectrum signal; The spectrum filtering processing method uses the notch filtering algorithm. The working principle of the notch filtering algorithm is to perform filtering in the frequency spectrum domain for specific polluted frequency bands to filter out the polluted signal components caused by the eddy current secondary radiation in the spectrum signal: First, construct a filter based on the notch filtering algorithm. The design parameters of the filter include the filter center frequency and the filter bandwidth. The filter center frequency is selected as the high - frequency harmonic frequency in the eddy current characteristic spectrum diagram, and the filter bandwidth is selected to fully cover the pollution energy distribution range corresponding to the high - frequency harmonic frequency points.

[0047] Pass the spectrum signal data stream through the notch filter to perform filtering processing. The steps of the filtering processing include: When the spectrum signal data stream passes through the notch filter, the amplitude values within the filter frequency range are attenuated to zero or close to zero, while the signal amplitude values within the frequency range outside the filter are retained without attenuation to maximize the retention of the energy information of the spectrum signal.

[0048] The spectral signal after removing the signal components contaminated by the secondary radiation of the eddy current is used as the purified real - environment spectrum; The data stream of the spectral signal obtained after filtering is the spectral signal after removing the signal components contaminated by the secondary radiation of the eddy current.

[0049] S6: Perform a joint time - frequency scan on the purified real - environment spectrum to detect the modulation characteristics and spatial orientation of the residual interference signal, and generate a power grid wireless communication interference source localization report, including: Perform a joint time - domain and frequency - domain scan on the purified real - environment spectrum to obtain the residual interference signal in the real - environment spectrum; Perform a joint time - domain and frequency - domain scan on the purified real - environment spectrum. The joint scan uses the short - time Fourier transform analysis technique. Specifically: Divide the purified real - environment spectrum into several consecutive short - time windows. The duration of each short - time window is set to a short time length that can reflect the transient characteristics of the residual interference signal, specifically an integer multiple of the power frequency period.

[0050] Perform a Fourier transform operation on the spectral signal within each short - time window respectively to obtain the frequency - amplitude distribution map of each short - time window.

[0051] Analyze the amplitude characteristics of the special abrupt peak signals in the frequency - amplitude distribution map. Define the signal with an amplitude exceeding the amplitude threshold of the normal background signal as the residual interference signal. The average amplitude value is obtained by summing up the amplitude values of each sampling point of the normal background signal within a period of time and then dividing by the number of sampling points; the variance is the sum of the squares of the differences between the amplitude values of each sampling point and the average amplitude divided by the number of sampling points. The amplitude threshold of the normal background signal is set to the average amplitude value plus three times the variance.

[0052] Adopt modulation recognition to extract the characteristic parameters of the residual interference signal in the real - environment spectrum; For the identified residual interference signal, use the high - order cumulant modulation recognition algorithm to identify the modulation type and extract the characteristic parameters of the residual interference signal. The high - order cumulant modulation recognition algorithm is not easily affected by Gaussian white noise interference and is suitable for the analysis of interference signals in a complex high - voltage substation environment.

[0053] Specifically, perform a fourth - order cumulant calculation on the data sequence of the identified residual interference signal. The calculation method of the fourth - order cumulant is to calculate the fourth - order moment of the data sequence of the residual interference signal, that is, the mean of the fourth - order products formed by the time - domain values of the sampling points of the residual interference signal in sequence, and then subtract the product of three second - order moments (such as three times the square of the second - order moment) to eliminate the interference of low - order statistical characteristics on the high - order feature analysis, so as to obtain the fourth - order cumulant.

[0054] Perform characteristic statistical analysis on the calculated fourth-order cumulant, extract the amplitude and phase statistical characteristics of the cumulant to determine the modulation type of the residual interference signal (amplitude modulation, frequency modulation, or phase modulation type).

[0055] Perform Fourier transform on the fourth-order cumulant to calculate the transformation result in the complex domain; then extract the amplitude feature and phase feature from the transformation result in the complex domain. The amplitude feature is the modulus of the complex value, that is, the square root of the sum of the squares of the real part and the imaginary part; the phase feature is the argument of the complex value, that is, the arctangent value of the ratio of the imaginary part to the real part; Calculate the statistical characteristics for the amplitude feature and phase feature respectively, including the mean value, standard deviation, and kurtosis. Perform type matching judgment based on the pre-established modulation feature database and determine whether the residual interference signal belongs to amplitude modulation, frequency modulation, or phase modulation type.

[0056] For amplitude modulation type, perform fast Fourier transform by analyzing the envelope signal of the residual interference signal, and calculate the maximum peak frequency, which is the modulation frequency; The carrier frequency is the center frequency of the main peak in the spectrum of the residual interference signal, determined by the peak position of the spectrum energy; The bandwidth is defined as the width of the frequency interval corresponding to the energy dropping to half of the maximum value on both sides of the main peak of the spectrum of the residual interference signal; The modulation index is determined by dividing the difference between the maximum and minimum amplitudes of the amplitude envelope signal by the sum of the maximum and minimum amplitudes.

[0057] For frequency modulation type, perform Hilbert transform on the instantaneous frequency of the residual interference signal, calculate the difference between the maximum and minimum values of the instantaneous frequency change, and then divide by the modulation frequency to determine the modulation index. The determination methods of the carrier frequency, modulation frequency, and bandwidth are the same as those of the amplitude modulation type.

[0058] For phase modulation type, calculate the maximum change amount of the instantaneous phase, which is the modulation index. The determination methods of the carrier frequency, modulation frequency, and bandwidth are the same as those of the amplitude modulation type.

[0059] The key characteristic parameters include but are not limited to the carrier frequency, modulation frequency, bandwidth, and modulation index.

[0060] Adopt the spatial spectrum estimation method, combined with the spatial coordinates of the spectrum monitoring equipment in the high-voltage substation, to determine the spatial orientation of the residual interference signal; The multiple signal classification algorithm is selected for the spatial spectrum estimation method, which is suitable for the accurate spatial positioning of interference sources in complex electromagnetic environments.

[0061] The spatial array signal of the residual interference signal collected by the array antenna adopted by the spectrum monitoring device is input into the multiple signal classification algorithm. The array antenna is arranged on the spectrum monitoring device, and the spatial coordinate information is measured by a laser rangefinder and an electronic compass and recorded as the three-dimensional spatial coordinate data of the high-voltage substation.

[0062] Calculate the covariance matrix of the spatial array signal using the spatial array signal, and then perform eigenvalue decomposition. The covariance matrix after eigenvalue decomposition is divided into a signal subspace and a noise subspace.

[0063] Calculate the spatial spectrum function using the noise subspace and the array manifold vector. The spatial spectrum estimation function refers to the function used to analyze the spatial signal azimuth in the spatial spectrum estimation algorithm (such as the multiple signal classification algorithm): after obtaining the noise subspace through eigenvalue decomposition of the signal received by the array antenna, substitute different spatial azimuth angles into the array manifold vector and perform matrix multiplication with the noise subspace, and then calculate the reciprocal of the matrix multiplication norm to obtain the spatial spectrum estimation value for each spatial azimuth angle. The array manifold vector refers to the spatial phase characteristic vector of the response of the array antenna elements when receiving electromagnetic wave signals incident from a specific spatial azimuth. It is obtained from the known array antenna structure parameters (array element layout geometry, spacing between array elements, number of array elements) and wavelength in the spectrum monitoring device.

[0064] Search for the spectral peaks of the spatial spectrum estimation function, and the spatial coordinate angles corresponding to the searched spectral peaks are the spatial azimuth angles of the residual interference signal. The spatial azimuth angles include the azimuth angle (i.e., the horizontal direction angle) and the elevation angle (i.e., the vertical direction angle).

[0065] Integrate the characteristic parameters and spatial azimuth angles of the residual interference signal to form a positioning report for the power grid wireless communication interference source; Integrate the characteristic parameters of the residual interference signal with the spatial azimuth. Combine the spatial coordinates of the spectrum monitoring device itself to calculate the position coordinates of the interference source within the high-voltage substation. The coordinate calculation method is the triangulation method, that is, using the position coordinates of the array antenna and the spatial azimuth estimated by the multiple signal classification algorithm, and calculating the precise position coordinates of the interference source in space through spatial geometric relationships.

[0066] The spatial geometric relationship is the three-dimensional spatial relationship between the position coordinates of the array antenna and the azimuth angle and elevation angle estimated by the multiple signal classification algorithm; Taking the position coordinates of the array antenna as the origin, construct a spatial trigonometric function relationship in combination with the azimuth angle and elevation angle; The spatial position coordinates of the interference source are calculated by the following method: Calculate the azimuth distance between the interference source and the array antenna, which is analyzed by the amplitude or time difference of the signal received by the array antenna; Taking the position coordinates of the array antenna as the reference point, based on the azimuth distance, azimuth angle, and elevation angle, the three-dimensional spatial position coordinates of the interference source are calculated through the conversion formula from spherical coordinates to rectangular coordinates in three-dimensional space (for example, the X coordinate of the rectangular coordinates is the azimuth distance multiplied by the cosine of the elevation angle and then multiplied by the cosine of the azimuth angle; the Y coordinate is the azimuth distance multiplied by the cosine of the elevation angle and then multiplied by the sine of the azimuth angle; the Z coordinate is the azimuth distance multiplied by the sine of the elevation angle).

[0067] Finally, a positioning report of the wireless communication interference source in the power grid is formed. The report includes information such as the modulation type, carrier frequency, bandwidth, modulation index, three-dimensional spatial position coordinates of the interference source, and detection time of the residual interference signal, which serves as the basis for implementing the investigation and management of the wireless communication interference source in the power grid.

[0068] The above formulas are all dimensionless and take their numerical calculations. The formula is a formula obtained by collecting a large amount of data for software simulation to get the closest to the real situation. The preset parameters and threshold selection in the formula are set by those skilled in the art according to the actual situation.

[0069] The above embodiments can be implemented in whole or in part by software, hardware, firmware, or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on a computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center by wired (such as infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that the computer can access or a data storage device such as a server or data center that contains one or more collections of available media. The available medium can be a magnetic medium (such as a floppy disk, hard disk, magnetic tape), an optical medium (such as a DVD), or a semiconductor medium. The semiconductor medium can be a solid-state drive.

[0070] Those of ordinary skill in the art will appreciate that the modules and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented in electronic hardware, or in a combination of computer software and electronic hardware. Whether these functions are executed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled professionals may use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of this application.

[0071] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, devices, and modules described above can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0072] In several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the modules is only a logical function division, and there can be other division methods in actual implementation. For example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces, and the indirect couplings or communication connections of the devices or modules can be in electrical, mechanical, or other forms.

[0073] The modules described as separate components may or may not be physically separated, and the components displayed as modules may or may not be physical modules. They can be located in one place or distributed to multiple network modules. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0074] In addition, the functional modules in each embodiment of this application can be integrated in a processing module, or each module can exist physically alone, or two or more modules can be integrated in one module.

[0075] If the above functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical discs.

[0076] As described above, the foregoing are only specific implementation manners of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art within the technical scope disclosed by this application can easily think of changes or substitutions, which should all be covered by the protection scope of this application. Therefore, the protection scope of this application shall be subject to the protection scope of the claims.

[0077] Finally: The foregoing are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall all be included in the protection scope of the present invention.

Claims

1. A spectrum monitoring and interference analysis method for power grid wireless communication, characterized in that It includes the following steps: S1: Based on the power frequency magnetic field intensity distribution data of the monitoring points, establish an eddy current distribution model for the spectrum monitoring device, and output an eddy current distribution parameter set induced by the power frequency magnetic field; S2: Collect the spectrum signals of the radio frequency receiving channel of the spectrum monitoring device and the power frequency magnetic flux density signals of the magnetic field sensing channel, and align the sampling points through a phase synchronization algorithm; S3: According to the eddy current distribution parameter set, calculate the high-frequency harmonic frequency point characteristics of the secondary radiation generated by the spectrum monitoring device under the power frequency magnetic field, and generate an eddy current characteristic spectrogram; S4: Extract the band energy value matching the eddy current characteristic spectrogram from the spectrum signals, and combine with the power frequency magnetic flux density signals to calculate the pollution ratio of the secondary radiation generated by the spectrum monitoring device under the power frequency magnetic field to the spectrum signals; S5: Based on the pollution ratio, eliminate the polluted signal components in the spectrum signals and output the purified real environment spectrum; S6: Perform a time-frequency joint scan on the purified real environment spectrum, detect the modulation characteristics and spatial orientation of the residual interference signals, and generate a power grid wireless communication interference source localization report.

2. The spectrum monitoring and interference analysis method for power grid wireless communication according to claim 1, characterized in that S1 is specifically as follows: Collect the power frequency magnetic field intensity distribution data of the monitoring points where the spectrum monitoring device is installed in the high-voltage substation; According to the structural parameter information of the spectrum monitoring device in the high-voltage substation, combined with the power frequency magnetic field intensity distribution data, establish an eddy current distribution model of the spectrum monitoring device under the action of the power frequency magnetic field; By analytically solving the electromagnetic induction equation, obtain the eddy current distribution parameter set of the spectrum monitoring device in the power frequency magnetic field environment.

3. A spectrum monitoring and interference analysis method for power grid wireless communication according to claim 2, characterized in that S2 is specifically as follows: Collect the spectrum signals in the radio frequency receiving channel of the spectrum monitoring device in the high-voltage substation; Collect the power frequency magnetic flux density signals in the magnetic field sensing channel of the spectrum monitoring device in the high-voltage substation; Adopt a phase synchronization algorithm based on the time synchronization reference signal to synchronize the spectrum signals collected by the radio frequency receiving channel of the spectrum monitoring device and the power frequency magnetic flux density signals collected by the magnetic field sensing channel, and align the sampling points of the spectrum signals and the power frequency magnetic flux density signals.

4. A spectrum monitoring and interference analysis method for wireless communication in a power grid according to claim 3, characterized in that, S3 is specifically as follows: According to the eddy current distribution parameter set, combined with the structural parameters of the spectrum monitoring device in the high-voltage substation, calculate the high-frequency harmonic frequency point characteristics generated by the spectrum monitoring device under the action of the power frequency magnetic field through the electromagnetic secondary radiation calculation model; The high-frequency harmonic frequency point characteristics include the high-frequency harmonic frequency values and the corresponding radiation amplitude values; Based on the Fourier transform and spectrum analysis methods, generate an eddy current characteristic spectrogram reflecting the high-frequency harmonic frequency point characteristics; The abscissa of the eddy current characteristic spectrogram represents the harmonic frequency, and the ordinate represents the electromagnetic radiation amplitude value corresponding to the harmonic frequency.

5. The spectrum monitoring and interference analysis method for power grid wireless communication according to claim 4, characterized in that S4 is specifically as follows: Perform frequency domain processing on the spectrum signals, and identify the band energy value corresponding to the eddy current characteristic spectrogram in the spectrum signals according to the high-frequency harmonic frequency point characteristics of the eddy current characteristic spectrogram; Calculate the change rate of the power frequency magnetic flux density of the power frequency magnetic flux density signal of the magnetic field sensing channel; Based on the band energy value and the change rate of the power frequency magnetic flux density, calculate the pollution ratio of the eddy current secondary radiation generated by the spectrum monitoring device under the action of the power frequency magnetic field to the spectrum signals.

6. The spectrum monitoring and interference analysis method for power grid wireless communication according to claim 5, characterized in that, S5 is specifically as follows: Identify the signal components contaminated by eddy current secondary radiation corresponding to the eddy current characteristic spectrogram in the spectrum signal according to the pollution ratio of the spectrum signal caused by the eddy current secondary radiation generated by the spectrum monitoring device under the action of the power frequency magnetic field; Based on the spectrum filtering processing method, remove the signal components contaminated by eddy current secondary radiation from the spectrum signal; Use the spectrum signal after removing the signal components contaminated by eddy current secondary radiation as the purified real environment spectrum.

7. A spectrum monitoring and interference analysis method for power grid wireless communication according to claim 6, characterized in that S6 is specifically as follows: Perform joint time-domain and frequency-domain scanning processing on the purified real environment spectrum to obtain the residual interference signals in the real environment spectrum; Adopt modulation recognition to extract the characteristic parameters of the residual interference signals in the real environment spectrum; Adopt the spatial spectrum estimation method, combined with the spatial coordinates of the spectrum monitoring device in the high-voltage substation, to determine the spatial orientation of the residual interference signals; Integrate the characteristic parameters and spatial azimuth angles of the residual interference signals to form a positioning report of the power grid wireless communication interference source.

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