CN114487589A - Power grid broadband signal self-adaptive measurement method, device and system - Google Patents

Power grid broadband signal self-adaptive measurement method, device and system Download PDF

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CN114487589A
CN114487589A CN202111607694.1A CN202111607694A CN114487589A CN 114487589 A CN114487589 A CN 114487589A CN 202111607694 A CN202111607694 A CN 202111607694A CN 114487589 A CN114487589 A CN 114487589A
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signal
main lobe
power grid
spectrum
spectral
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张敏
滕贤亮
彭佳伟
沈健
潘树国
侯明国
夏成林
高旺
汪鹤
陈力
殷垚
彭奇
魏洁茹
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Nari Technology Co Ltd
NARI Nanjing Control System Co Ltd
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NARI Nanjing Control System Co Ltd
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R22/00—Arrangements for measuring time integral of electric power or current, e.g. electricity meters
    • G01R22/06—Arrangements for measuring time integral of electric power or current, e.g. electricity meters by electronic methods
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R23/00—Arrangements for measuring frequencies; Arrangements for analysing frequency spectra
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Abstract

The invention discloses a power grid broadband signal self-adaptive measurement method, a device and a system, wherein the method comprises the following steps: acquiring a signal frequency spectrum and a signal main lobe interference condition of a power grid broadband signal; and according to the signal main lobe interference condition, adaptively adopting a double spectral line interpolation algorithm or a complex modulation refinement spectrum analysis method to estimate signal parameters of the signal frequency spectrum to obtain all parameters of the power grid broadband signal. The method utilizes the phase characteristics of signal spectrum lines to perform self-adaptive judgment on signal main lobe interference, adopts a complex modulation refined spectrum analysis method to perform parameter estimation aiming at the signal spectrum with the main lobe interference, and adopts a double-spectral-line interpolation algorithm to perform estimation aiming at the signal spectrum without the main lobe interference. The invention effectively realizes the high-precision self-adaptive measurement of the harmonic wave in the wide frequency range.

Description

Power grid broadband signal self-adaptive measurement method, device and system
Technical Field
The invention belongs to the technical field of power system broadband signal measurement, and particularly relates to a power grid broadband signal self-adaptive measurement method, device and system.
Background
The method can accurately measure the component of each component in the power grid signal in real time, and is an important guarantee for the safe and stable operation of the power grid. However, the conventional synchronous Phasor Measurement Unit (PMU), power quality monitoring device and Measurement algorithm are mostly directed to Measurement of power frequency and harmonic below 20 times, and cannot comprehensively monitor power grid signals within a wide frequency range of 0-2.5 kHz. In addition, the existing measurement algorithm is mostly limited to power frequency and harmonic signal measurement, and the inter-harmonic frequency resolution of the power quality detection device only reaches 5Hz, so that the resolution requirements of all signals in a wide frequency range are difficult to meet.
In the aspect of measuring algorithms aiming at harmonic and inter-harmonic signals, Fast Fourier Transform (FFT) is a spectrum analysis method which is most applied, wherein the measurement algorithm of windowing interpolation correction has the advantages of small operand and stable measurement precision, but when spectral lines used for interpolation correction are influenced by spectral line interference, the correction precision is greatly reduced, and the algorithm cannot effectively measure harmonic waves and inter-harmonic waves with similar frequencies under the condition of ensuring the real-time performance of the algorithm.
The complex modulation refinement spectrum analysis method (ZoomFFT) can perform frequency domain analysis on a specific frequency range with higher resolution and realize measurement on signal components with similar frequencies, but cannot realize comprehensive measurement in a wide frequency range of 0-2.5 kHz. Modern spectrum estimation algorithms based on a multiple signal classification Method (MUSIC) and a rotation invariant parameter estimation method (ESPRIT) have the characteristic of super-resolution, but the calculation amount is large, the information source number estimation process is easily influenced by noise, and the algorithm precision is sharply reduced.
Disclosure of Invention
In order to solve the problems, the invention provides a power grid broadband signal adaptive measurement method, a device and a system, which can realize high-precision adaptive measurement of power grid harmonics and frequency-close inter-harmonics in a broadband range.
In order to achieve the technical purpose and achieve the technical effects, the invention is realized by the following technical scheme:
in a first aspect, the present invention provides a power grid broadband signal adaptive measurement method, including:
acquiring a signal frequency spectrum and a signal main lobe interference condition of a power grid broadband signal;
and according to the signal main lobe interference condition, adaptively adopting a double spectral line interpolation algorithm or a complex modulation refining spectrum analysis method to carry out signal parameter estimation on the signal frequency spectrum to obtain all parameters of the power grid broadband signal.
Optionally, the acquiring a signal spectrum of the grid broadband signal includes:
carrying out N-point sampling on the power grid broadband signal to obtain a sampling sequence;
and adding 4 items of 5-order Nuttall windows to the sampling sequence, and performing discrete Fourier transform to obtain the signal frequency spectrum.
Optionally, the method for acquiring a signal main lobe interference condition includes:
sampling the signal frequency spectrum to obtain a digital frequency spectrum;
and when the spectral line in the digital spectrum main lobe is not influenced by signal components of other frequencies based on the digital spectrum, obtaining the signal main lobe interference condition by using the spectral line phase characteristics.
Alternatively, when the absolute value of the phase difference of adjacent spectral lines in the digital spectral main lobe is pi, it is determined that the spectral lines in the digital spectral main lobe are not affected by signal components of other frequencies.
Optionally, the signal main lobe interference condition comprises absence of interference of spectral lines in a main lobe or presence of interference of spectral lines in a main lobe; the obtaining of the signal main lobe interference condition by using the spectral line phase characteristics specifically includes:
the maximum value of the difference between the phase difference and pi between adjacent spectral lines in each main lobe of the digital frequency spectrum
Figure BDA0003434446930000021
Compared to a threshold epsilon;
when it is satisfied with
Figure BDA0003434446930000022
Then the spectral lines in the main lobe are considered to be free of interference:
when it satisfies
Figure BDA0003434446930000023
The spectral lines in the main lobe are considered to be disturbed.
Optionally, the signal parameter estimation is performed on the signal spectrum by adaptively adopting a dual-spectral-line interpolation algorithm or a complex modulation refined spectrum analysis method according to the signal main lobe interference condition, and specifically includes:
when the spectral line in the main lobe has no interference, performing parameter estimation on the signal spectrum without the main lobe interference by adopting a 4-item 5-order Nuttall window-based dual spectral line interpolation correction algorithm;
and when the spectral line in the main lobe has interference, performing parameter estimation on the signal spectrum with the main lobe interference by adopting a complex modulation refined spectrum analysis method.
In a second aspect, the present invention provides an adaptive measurement apparatus for a broadband signal of a power grid, including:
the signal processing module is used for acquiring a signal frequency spectrum of the power grid broadband signal and a signal main lobe interference condition;
and the parameter estimation module is used for adaptively adopting a double spectral line interpolation algorithm or a complex modulation refinement spectrum analysis method according to the signal main lobe interference condition to carry out signal parameter estimation on the signal frequency spectrum to obtain all parameters of the power grid broadband signal.
In a third aspect, the invention provides a power grid broadband signal adaptive measurement system, which comprises a storage medium and a processor;
the storage medium is used for storing instructions;
the processor is configured to operate in accordance with the instructions to perform the steps of the method according to any one of claims 1 to 6.
In a fourth aspect, the present invention provides a computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the steps of the method according to any one of the first aspect when executing the computer program.
In a fifth aspect, the invention provides a computer-readable storage medium, on which a computer program is stored, characterized in that the computer program, when executed by a processor, implements the steps of the method of any one of the first aspects.
Compared with the prior art, the invention has the beneficial effects that:
the method comprises the steps of judging whether main lobe interference exists or not by utilizing the phase characteristics of a signal frequency spectrum, adaptively adopting a double-spectral-line interpolation correction algorithm which is small in calculated amount and meets harmonic measurement and a complex modulation refined spectrum analysis method which is higher in resolution and meets measurement of frequency-close inter-harmonics and low-amplitude higher harmonics according to a judgment result, effectively realizing high-precision adaptive measurement of the harmonic and the frequency-close inter-harmonics within the range of 0-2.5 kHz, and enabling the measurement requirement of a broadband power grid to be met by higher measurement precision and lower operation cost.
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In order that the present disclosure may be more readily and clearly understood, reference is now made to the following detailed description of the present disclosure taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a schematic flow diagram of the process of the present invention;
FIG. 2(a) is one of the grid signal measurements and relative error plots of the method of the present invention;
FIG. 2(b) is a graph of grid signal measurements and a second relative error plot for the method of the present invention;
FIG. 2(c) is a third graph of grid signal measurements and relative error for the method of the present invention;
fig. 3 is a waveform diagram of a measured three-phase voltage signal of a power grid in 10 fundamental wave periods.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of the invention.
The following detailed description of the principles of the invention is provided in connection with the accompanying drawings.
Example 1
As shown in fig. 1, the present invention provides a power grid broadband signal adaptive measurement method, which comprises the following specific steps:
acquiring a signal frequency spectrum and a signal main lobe interference condition of a power grid broadband signal;
and according to the signal main lobe interference condition, adaptively adopting a double spectral line interpolation algorithm or a complex modulation refinement spectrum analysis method (ZoomFFT algorithm) to estimate signal parameters of the signal frequency spectrum to obtain all parameters of the power grid broadband signal.
In a specific implementation manner of the embodiment of the present invention, the method for acquiring a signal spectrum includes:
at a sampling frequency fsCarrying out N-point sampling on the power grid broadband signal to obtain a sampling sequence; the expression of the power grid broadband signal is as follows:
Figure BDA0003434446930000031
wherein A ism、fm、
Figure BDA0003434446930000032
The amplitude, the frequency and the phase of the mth signal component in the power grid broadband signal are respectively, and M is the number of the signal components in the power grid broadband signal;
adding 4 items of 5-order Nuttall windows to the sampling sequence, and performing discrete Fourier transform to obtain the signal frequency spectrum; the expression of the signal spectrum is:
Figure BDA0003434446930000041
wherein, X (e)jw) Is the signal spectrum, W4(ω) is the amplitude spectrum of a 4-term 5-order Nuttall window, ωmIs fmThe digital angular frequency of (c).
In a specific implementation manner of the embodiment of the present invention, the method for acquiring a signal main lobe interference condition includes:
for signal spectrum X (e) at intervals of 2 pi/Njw) Sampling is carried out to obtain a digital frequency spectrum, namely a digital frequency representation form of the signal frequency spectrum is obtained, and the method specifically comprises the following steps:
Figure BDA0003434446930000042
wherein, λ is N ω/2 π, λm＝Nωm/2π＝Nfm/fs，
Figure BDA0003434446930000043
WR(λ) ═ sin (λ pi)/sin (λ pi/N) is a rectangular window magnitude spectrum expressed in digital frequencies;
when the spectral line in the digital spectrum main lobe is not influenced by signal components of other frequencies based on the digital spectrum, obtaining the signal main lobe interference condition by using the spectral line phase characteristic;
in the specific implementation process, when the absolute value of the phase difference between adjacent spectral lines in the digital spectrum main lobe is pi, it is determined that the spectral lines in the digital spectrum main lobe are not affected by signal components of other frequencies, and the calculation formula of the absolute value of the phase difference between the adjacent spectral lines is as follows:
Figure BDA0003434446930000044
wherein, X (·) is amplitude frequency line value, i is the serial number of peak value line in main lobe, k is the serial number of difference between phase difference and pi between lines, and k is 1,2,3, 4.
The signal main lobe interference condition comprises that no interference exists in spectral lines in a main lobe or interference exists in spectral lines in the main lobe; the obtaining of the signal main lobe interference condition by using the spectral line phase characteristics specifically includes:
the maximum value of the difference between the phase difference and pi between adjacent spectral lines in each main lobe of the digital frequency spectrum
Figure BDA0003434446930000045
Compared to a threshold epsilon;
when it is satisfied with
Figure BDA0003434446930000046
Then the spectral lines in the main lobe are considered to be free of interference (i.e. there is only one signal component at this spectrum):
when it satisfies
Figure BDA0003434446930000047
The spectral lines in the main lobe are considered to be disturbing (i.e. there are only signal components at this spectrum).
In a specific implementation manner of the embodiment of the present invention, the adaptively estimating signal parameters of the signal spectrum by using a dual spectral line interpolation algorithm or a complex modulation refined spectrum analysis method according to the signal main lobe interference condition specifically includes:
when the spectral line in the main lobe has interference, performing parameter estimation on the signal spectrum with the main lobe interference by adopting a 4-item 5-order Nuttall window-based dual spectral line interpolation correction algorithm;
and when the spectral line in the main lobe has no interference, performing parameter estimation on the signal spectrum without the main lobe interference by adopting a complex modulation refined spectrum analysis method.
The method for estimating the parameters of the signal spectrum without the main lobe interference by adopting a 4-item 5-order Nuttall window-based dual spectral line interpolation correction algorithm specifically comprises the following steps of:
calculating the spectral line amplitude ratio beta of any two adjacent frequency pointsmSaid line amplitude ratio βmThe calculation formula of (2) is as follows:
Figure BDA0003434446930000051
combining said line amplitude ratios betamCalculating the signal frequency fmCorresponding digital frequency position lambdamSaid digital frequency position λmThe calculation formula of (2) is as follows:
λm＝km+δm
wherein k ismIs a sampling point of a positive integer, δmIs an interpolation coefficient, and δm∈[0,1)；
Performing parameter estimation of a signal frequency spectrum according to the 4-item 5-order Nuttall window double-spectral-line interpolation correction algorithm; the frequency, amplitude and phase parameter estimation formulas of the 4-item 5-order Nuttall window double-spectral-line interpolation correction algorithm are respectively as follows:
Figure BDA0003434446930000052
Figure BDA0003434446930000053
Figure BDA0003434446930000054
wherein f ism、Am、
Figure BDA0003434446930000055
Frequency, amplitude and phase, k, respectively, of the mth signal componentmIs a sampling point of a positive integer, δmAs interpolation coefficient, fsThe sampling frequency is N is the number of sampling points.
The method for performing parameter estimation on the signal frequency spectrum with the main lobe interference by adopting the complex modulation refined spectrum analysis method specifically comprises the following steps:
after windowing and sampling are carried out on the power grid broadband signal, N is obtainedZFFTA time-domain sequence of DN points, D being a refinement multiple, said time-domain sequence being multiplied by a unit twiddle factor
Figure BDA0003434446930000056
Performing complex modulation frequency shift to form a frequency f corresponding to a spectral line with main lobe interference in a frequency spectrumiNew signal y (n) which is a frequency zero;
after FFT conversion is carried out on the new signal y (n), low-pass digital filtering is carried out on the obtained frequency domain sequence (namely frequency spectrum);
IFFT with the length of DN is carried out on the frequency domain sequence after the low-pass digital filtering to obtain a time domain sequence, resampling is carried out, the sampling interval is D, and the sampling frequency is changed into fs/D；
Performing FFT on the N-point time domain sequence obtained after resampling, and rearranging by moving the zero-frequency component to the center of the sequence, wherein the frequency resolution is (f)s/D)/N＝fs/DN；
According to the FFT result obtained by rearrangement, the frequency f of the power grid broadband signal can be obtainediCentering and refining the frequency range fsThe frequency spectrum characteristic in/D realizes the parameter estimation of the signal frequency spectrum in the frequency range, and the frequency, amplitude and phase parameter estimation formulas of the complex modulation fine spectrum analysis method are respectively as follows:
Figure BDA0003434446930000061
A＝|X(ki)|
Figure BDA0003434446930000062
wherein f, A,
Figure BDA0003434446930000063
Frequency, amplitude and phase, k, respectively, of the signal component corresponding to the frequency spectrum line in which the main lobe interference is presentiFor digital frequency points in which main-lobe interference lines are present, fsIs the sampling frequency, NZFFTThe number of sampling points of complex modulation refining spectrum analysis method is shown, D is a refining multiple, and X (k)i) Is the spectrum of the signal in digital frequencies.
The following describes in detail the application of the method in the examples of the present invention in conjunction with a specific embodiment.
(1) Firstly, a threshold epsilon for judging main lobe interference needs to be analyzed and determined: since the value of the threshold value epsilon directly affects the self-adaptability of the measurement method in the embodiment of the invention, the misjudgment of the main lobe interference can be caused when the value is small, and the misjudgment can be caused when the value is large, so that the signal parameter cannot be effectively estimated, and the method is invalid. After simulation traversal is performed on signal components with different amplitude ratios and frequency differences under different signal-to-noise ratios, unnecessary operation is avoided as much as possible on the premise that the signal components (such as components with similar or low amplitude values) which cannot be effectively subjected to parameter estimation by a spectral line interpolation method can be effectively identified, and then the threshold is set to be epsilon 1.4.
(2) The method provided by the invention is adopted to measure the broadband signal of the power grid, and a simulation signal is constructed:
combining the characteristics of the actual power grid broadband signal, the signal-to-noise ratio SNR of a certain power grid signal containing fundamental waves, various harmonics and inter-harmonics is set to be 60dB, and the parameter set values are shown in Table 1.
TABLE 1 simulation Signal parameter settings
Figure BDA0003434446930000064
Figure BDA0003434446930000071
Setting the sampling frequency to fsThe sampled signal spectral analysis time window is set to 10 fundamental wave periods, i.e. the number of sampling points N ≈ 1280, according to the international electrotechnical commission standard IEC 61000-4-30. Setting the thinning multiple D of the ZoomFFT to 50 and the number of sampling points NZFFT＝12800。
Because the signal component with lower amplitude is susceptible to the influence of background noise or other signal component frequency spectrum leakage to generate main lobe interference, the signal is simulated and measured for 100 times, and then the measurement result is averaged to ensure the reliability of the simulation result. The simulation measurement results are shown in table 2, fig. 2(a) -fig. 2(c), wherein the error bar size is the standard deviation of error of each signal component parameter, i.e., ± σ, and is used for indicating the accuracy stability of the method provided by the present invention.
TABLE 2 measurement of the broadband signal of the power grid
Figure BDA0003434446930000072
Simulation results show that the method effectively realizes the self-adaptive measurement of signals, wherein the ZoomFFT algorithm estimates fundamental waves, nearby inter-harmonics thereof and inter-harmonic parameters of which the frequency difference is only 1Hz, and the 4-item 5-order Nuttall window-based dual-spectral-line interpolation correction algorithm measures harmonic components without generating main lobe interference. In addition, although no other signal component exists near the 35 th harmonic and the 49 th harmonic, the lower amplitude makes the signal component susceptible to spectral leakage and background noise to generate main lobe interference, so that both algorithms perform parameter estimation of the component in the simulation process.
Compared with a 4-item 5-order Nuttall window-based dual-spectral line interpolation correction algorithm, the integral measurement result of the ZoomFFT algorithm is more stable, and error fluctuation is smallerThe frequency estimation precision is higher, the accurate estimation of the frequency parameter is realized, but the amplitude estimation precision is slightly lower than that of the amplitude estimation precision, the parameter estimation error fluctuation of the high-order harmonics is larger, and the two algorithms are basically equivalent in the phase estimation precision. In conclusion, the method provided by the invention has the advantages of higher overall precision, good stability and frequency relative error lower than 7 multiplied by 10-5The magnitude of the error is 10-4～10-3Phase error not exceeding 1.6 x 10-2。
(3) The method of the invention is adopted to measure the measured voltage signal of the power grid:
the method provided by the invention is utilized to analyze the three-phase voltage recording data (shown in figure 3) of the 220kV bus of the water spring wind power plant behind the wind power of the middle vehicle, the voltage transformation ratio is 220kV/100V, the recording data is obtained by continuous wave recording of a synchronous phasor measurement unit (SMU-2ME) installed and deployed on the site, the sampling frequency is 6.4kHz, the initial data length N of the method is 1280, if main lobe interference exists, the initial data length N is increased to 12800 so as to meet the operation requirement of ZoomFFT, the main lobe interference judgment threshold is still 1.4, and the parameter estimation result is shown in table 3.
TABLE 3 measured Voltage Signal measurement results
Figure BDA0003434446930000081
From the results, it can be seen that the present invention effectively estimates various signal parameters. In terms of frequency, the fundamental frequency of the voltage signal is free of frequency shift and free of inter-harmonics, but there are multiple low-amplitude harmonic components in the signal up to 13 th order. In the aspect of amplitude, the mean value of the fundamental frequency phase voltage is 57.734V, the corresponding line voltage is 99.998V, the actual voltage transformation ratio is met, and the amplitude estimation precision is high. In addition, there is some degree of imbalance between the three phases, such as 13 th harmonics in only the A and B phases, which may not be present in the other phases or may be below 0.1V in magnitude. In terms of phase, the phase estimation result is verified by whether each inter-phase difference is 120 degrees or not at this time:
Figure BDA0003434446930000082
wherein the content of the first and second substances,
Figure BDA0003434446930000083
respectively, of three-phase, thetaA、θB、θCFor phase deviation, there are:
Figure BDA0003434446930000084
wherein the content of the first and second substances,
Figure BDA0003434446930000091
the unbalance degree is used for representing the unbalance degree of each phase under the actual operation condition of the power grid, and under the ideal operation condition of the power grid, the unbalance degree is
Figure BDA0003434446930000092
e. For phase estimation errors, i.e. method errors introduced by the measurement method, there are now:
Figure BDA0003434446930000093
since the recorded wave data has black box and the phase is relative value, the sum of the absolute values of the unbalance degrees of the harmonic components is considered as constant, that is
Figure BDA0003434446930000096
Furthermore, the mean value of the absolute phase deviation can be used to roughly measure the phase estimation error of the measurement method, which includes:
Figure BDA0003434446930000094
the phase estimation results of the harmonic components stably existing in all three phases at this time and the average value of the absolute phase deviation thereof are shown in table 4.
TABLE 4 phase estimation results and mean of absolute phase deviations
Figure BDA0003434446930000095
On the one hand, it can be seen that the three phases of the voltage signal are relatively balanced, wherein the phase difference between the phases of the power frequency is substantially 120 °. On the other hand, in an actual situation, the odd harmonics in the power grid signal generally have a certain degree of three-phase imbalance, the imbalance degree is related to factors such as a harmonic source and an amplitude, and if it is assumed that the method error e is influenced by the component amplitude and fluctuates slightly around a fixed value, it can be seen that the imbalance degree of each harmonic is consistent with the actual situation. In conclusion, the measurement method provided by the invention can realize high-precision phase estimation.
Example 2
Based on the same inventive concept as embodiment 1, an embodiment of the present invention provides an adaptive measurement apparatus for a broadband signal of a power grid, including:
the signal processing module is used for acquiring a signal frequency spectrum of the power grid broadband signal and a signal main lobe interference condition;
and the parameter estimation module is used for adaptively adopting a double spectral line interpolation algorithm or a complex modulation refinement spectrum analysis method according to the signal main lobe interference condition to carry out signal parameter estimation on the signal frequency spectrum to obtain all parameters of the power grid broadband signal.
The rest of the process was the same as in example 1.
Example 3
The embodiment of the invention provides a power grid broadband signal self-adaptive measurement system, which comprises a storage medium and a processor, wherein the storage medium is used for storing a plurality of power grid broadband signals;
the storage medium is used for storing instructions;
the processor is configured to operate in accordance with the instructions to perform the steps of the method according to any of embodiment 1.
Example 4
The embodiment of the present invention provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method according to any one of embodiment 1 when executing the computer program.
Example 5
An embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored, where the computer program is executed by a processor to implement the steps of the method according to any one of embodiment 1.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.

Claims (10)

1. A power grid broadband signal self-adaptive measurement method is characterized by comprising the following steps:
acquiring a signal frequency spectrum and a signal main lobe interference condition of a power grid broadband signal;
and according to the signal main lobe interference condition, adaptively adopting a double spectral line interpolation algorithm or a complex modulation refining spectrum analysis method to carry out signal parameter estimation on the signal frequency spectrum to obtain all parameters of the power grid broadband signal.
2. The adaptive measurement method for broadband signals of power grid according to claim 1, wherein: the acquiring of the signal spectrum of the broadband signal of the power grid includes:
carrying out N-point sampling on the power grid broadband signal to obtain a sampling sequence;
and adding 4 items of 5-order Nuttall windows to the sampling sequence, and performing discrete Fourier transform to obtain the signal frequency spectrum.
3. The adaptive measurement method for broadband signals of power grid according to claim 1, wherein: the method for acquiring the signal main lobe interference condition comprises the following steps:
sampling the signal frequency spectrum to obtain a digital frequency spectrum;
and when the spectral line in the digital spectrum main lobe is not influenced by signal components of other frequencies based on the digital spectrum, obtaining the signal main lobe interference condition by using the spectral line phase characteristics.
4. The adaptive measurement method for broadband signals in power grid according to claim 3, wherein when the absolute value of the phase difference between adjacent spectral lines in the digital spectral main lobe is pi, it is determined that the spectral lines in the digital spectral main lobe are not affected by signal components of other frequencies.
5. The adaptive measurement method for the broadband signal of the power grid according to claim 3, wherein the signal main lobe interference condition includes that no interference exists in the spectral lines of the main lobe or interference exists in the spectral lines of the main lobe; the obtaining of the signal main lobe interference condition by using the spectral line phase characteristics specifically includes:
the maximum value of the difference between the phase difference and pi between adjacent spectral lines in each main lobe of the digital frequency spectrum
Figure FDA0003434446920000011
Compared to a threshold epsilon;
when it is satisfied with
Figure FDA0003434446920000012
Then the spectral lines in the main lobe are considered to be free of interference:
when it satisfies
Figure FDA0003434446920000013
The spectral lines in the main lobe are considered to be disturbed.
6. The adaptive measurement method for broadband signals of power grid according to claim 5, wherein: according to the signal main lobe interference condition, adaptively adopting a double-spectral-line interpolation algorithm or a complex modulation refinement spectrum analysis method to estimate the signal parameters of the signal frequency spectrum, and specifically comprising the following steps of:
when the spectral line in the main lobe has no interference, performing parameter estimation on the signal spectrum without the main lobe interference by adopting a 4-item 5-order Nuttall window-based dual spectral line interpolation correction algorithm;
and when the spectral line in the main lobe has interference, performing parameter estimation on the signal spectrum with the main lobe interference by adopting a complex modulation refined spectrum analysis method.
7. A self-adaptive measuring device for broadband signals of a power grid is characterized by comprising:
the signal processing module is used for acquiring a signal frequency spectrum of the power grid broadband signal and a signal main lobe interference condition;
and the parameter estimation module is used for adaptively adopting a double spectral line interpolation algorithm or a complex modulation refinement spectrum analysis method according to the signal main lobe interference condition to carry out signal parameter estimation on the signal frequency spectrum to obtain all parameters of the power grid broadband signal.
8. A power grid broadband signal self-adaptive measurement system is characterized by comprising a storage medium and a processor;
the storage medium is used for storing instructions;
the processor is configured to operate in accordance with the instructions to perform the steps of the method according to any one of claims 1 to 6.
9. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the steps of the method according to any of claims 1-6 are implemented when the computer program is executed by the processor.
10. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 6.
CN202111607694.1A 2021-12-27 2021-12-27 Power grid broadband signal self-adaptive measurement method, device and system Pending CN114487589A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116735957A (en) * 2023-06-07 2023-09-12 四川大学 Near-frequency harmonic wave and inter-harmonic wave measuring method and system considering main lobe overlapping interference

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116735957A (en) * 2023-06-07 2023-09-12 四川大学 Near-frequency harmonic wave and inter-harmonic wave measuring method and system considering main lobe overlapping interference
CN116735957B (en) * 2023-06-07 2024-02-27 四川大学 Near-frequency harmonic wave and inter-harmonic wave measuring method and system considering main lobe overlapping interference

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