A filtering method and device for single-channel aliasing signal of power grid harmonics

Abstract

The present application discloses a filtering method for a single-channel aliased signal of power grid harmonics, comprising the following steps: receiving a signal transmitted along the power grid for sampling to generate an original time domain signal; performing carrier modulation on the time domain power frequency fundamental wave, moving the time domain power frequency fundamental wave to a specific frequency point, and constructing a clutter reference signal; using the constructed clutter reference signal and the original time domain signal as input parameters of an adaptive filter to extract the clutter signal in the original time domain signal; and finally subtracting the clutter signal output by the filter in the previous step from the original time domain signal. The present application also includes a device for implementing the method. The present application solves the problem that it is difficult to distinguish between a target signal and a power grid harmonic signal when they are aliased.

Description

Technical Field

[0001] The present application relates to the technical field of radio signal processing, and is a filtering method for target signals aliased in power grid harmonics, for processing the situation where the target signal and power grid harmonics are aliased and there is only one receiving channel. Background Art

[0002] Due to the inherent nonlinearity of the power source and the shifting operation of the rectifier in the electrical equipment, the electromagnetic signals emitted by the power supply system during normal operation and when a fault occurs will generate various harmonics, and sometimes contain mutation signals or high-frequency resonance interference. On the one hand, the emergence of harmonics reduces the efficiency of power production, transmission and utilization, and also causes electrical equipment to overheat, generate vibration and noise, and age the insulation, shorten the service life, and even cause failure or burnout; on the other hand, due to the rapid development of power electronics technology, various power electronic devices are increasingly used in power systems, industry, transportation and homes, which also has some impact on radio signal detection. Since the 1970s, countries around the world have paid full attention to the harmonic problem. Many academic conferences on harmonic issues have been held internationally, and many countries and international academic organizations have formulated standards and regulations to limit power system harmonics and harmonics of electrical equipment. Existing research on power grid harmonics can be divided into two categories: First, some work done on hardware equipment based on the causes of harmonic generation, mainly installing harmonic compensation devices to compensate for harmonics and modifying the power electronic devices themselves so that they do not generate harmonics; Second, the analysis of the power grid harmonic signal itself, mainly using spectrum analysis methods such as fast Fourier transform and wavelet transform. Research on the single-channel aliasing of target signals and power grid harmonic signals is currently rare. Summary of the invention

[0003] The purpose of the present invention is to disclose a filtering method for a single-channel aliased signal of a power grid harmonic, so as to solve the problem that it is difficult to distinguish a target signal from a power grid harmonic signal when the target signal is aliased, so as to extract the target signal of interest aliased in the power grid harmonic.

[0004] The present application embodiment provides a method for filtering a single-channel aliased signal of a power grid harmonic, comprising the following steps:

[0005] Receive power grid radiation signals, perform sampling, and generate original time domain signals;

[0006] Carrier modulate the time domain power frequency fundamental wave, move the time domain power frequency fundamental wave to a specific frequency point, and construct a clutter reference signal;

[0007] The constructed clutter reference signal and the original time domain signal are used as input parameters of the adaptive filter to extract the clutter signal in the original time domain signal;

[0008] Finally, the clutter signal output by the filter in the previous step is subtracted from the original time domain signal to obtain the target signal after clutter cancellation.

[0009] Preferably, the time-domain industrial frequency fundamental wave signal is generated by filtering an original time-domain signal, or the time-domain industrial frequency fundamental wave signal is a setting signal.

[0010] Regarding the specific frequency point, preferably, the specific frequency point is an odd multiple of the fundamental frequency of the time domain power frequency fundamental signal; further preferably, the specific frequency point is one or more. As a further optimized embodiment of the present application, before the above steps, the a priori target signal is subjected to frequency domain analysis to obtain the value of the specific frequency point.

[0011] The embodiments of the present application also provide a computer device and a storage medium for implementing the method described in any one of the embodiments.

[0012] At least one of the above technical solutions adopted in the embodiments of the present application can achieve the following beneficial effects:

[0013] By studying the generation mechanism of power grid harmonics and experimental analysis and verification, the signal characteristics of power grid harmonic signals are given, and based on this characteristic, a clutter reference signal is constructed to complete clutter cancellation, overcoming the defect of the existing algorithm that clutter cancellation cannot be performed due to insufficient number of channels; through experimental analysis and verification of the target signal, the prior information of the target signal is obtained, and based on this prior information, a target reference signal is constructed to complete the target signal purification; experimental verification shows that both methods can effectively filter out most of the background clutter, providing a solution for filtering single-channel aliasing signals contaminated by power grid harmonics.

[0014] The two technical solutions proposed in the present invention, by studying the generation mechanism of power grid harmonics and experimental analysis and verification, give the signal characteristics of power grid harmonic signals, and perform single-channel adaptive filtering based on this characteristic, thus overcoming the defect of the existing algorithm that adaptive filtering cannot be performed due to insufficient number of channels. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0016] Figure 1 This is a flow chart of an embodiment of the method of this application;

[0017] Figure 2 The phase of the power frequency harmonic signal changes with time;

[0018] Figure 3 is the target signal phase variation over time.

[0019] Figure 4 The flowchart of the embodiment based on real-time extraction of power frequency fundamental wave;

[0020] Figure 5 An adaptive filter structure constructed according to noise characteristics;

[0021] Figure 6 This is the flow chart of the Wiener filter algorithm;

[0022] Figure 7 This is the spectrum comparison diagram before and after clutter cancellation;

[0023] Figure 8 This is a flow chart of another embodiment of the method of the present application;

[0024] Fig. 9 This is a spectrum comparison chart before and after the target signal is purified. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in combination with the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0026] This patent is used to solve the problem of detecting a signal with a stable frequency in a single-channel power grid harmonic. The target signal refers to a signal with some prior information. The specific application scenario is that a certain device will generate a signal with a stable frequency when it is powered on, because the signal is generated when the device is powered on, and in the real scene, as long as electricity is used, the corresponding power grid harmonic interference will be generated. Therefore, when performing electromagnetic detection, the signal will inevitably be mixed with the harmonic signal generated in the power grid. At this time, the signal with a stable frequency in the aliased signal is the target signal, and the others are background clutter signals. By detecting whether the received single-channel aliased signal has such a stable frequency signal, it is determined whether the device exists. In order to achieve the above purpose, the present invention provides two filtering methods for single-channel aliased signals of power grid harmonics, including a clutter cancellation method and a target signal purification method.

[0027] The technical solutions provided by various embodiments of the present application are described in detail below in conjunction with the accompanying drawings.

[0028] Figure 1 This is a flow chart of an embodiment of the method of this application;

[0029] The present application embodiment provides a method for filtering a single-channel aliased signal of a power grid harmonic, comprising the following steps:

[0030] Step 11: Receive the power grid radiation signal, perform sampling, and generate the original time domain signal.

[0031] Since the inductive magnetic field sensor detects the change of the magnetic field and converts this change into an electrical signal, the receiver samples the received electrical signal to obtain the original time domain signal.

[0032] The collected single-channel electromagnetic signal is understood as:

[0033] s(t)=s1(t)+n(t)=s1(t)+s2(t)+n'(t) (1)

[0034] Where s(t) represents the collected electromagnetic signal, s1(t) represents the target signal, n(t) represents the sum of the power frequency fundamental signal and the power grid harmonic signal, s2(t) represents the power frequency fundamental signal, and n'(t) represents the power grid harmonic signal.

[0035] Step 12: Carrier modulation calculation is performed on the time-domain power frequency fundamental wave, and the time-domain power frequency fundamental wave is moved to a specific frequency point to construct a clutter reference signal.

[0036] Regarding the specific frequency point, preferably, the specific frequency point is an integer multiple of the fundamental frequency of the time-domain industrial frequency fundamental signal; further preferably, the specific frequency point is one or more.

[0037] The method of the present application constructs a clutter reference signal by shifting an industrial frequency fundamental wave signal, wherein the clutter here specifically refers to the Nth harmonic in the power grid that is at the same frequency as the target signal.

[0038] To explain more clearly, the following example is given

[0039] If a signal is a periodic signal with a frequency of f, then the signal is composed only of frequency components whose frequencies are integer multiples of f, such as f, 2f, 3f, 4f, etc. These frequency components are called harmonics.

[0040] Assuming f(t) is a function with a period of T, any periodic signal can be decomposed into the following form:

[0041]

[0042] The Fourier coefficients are expressed as follows:

[0043]

[0044]

[0045]

[0046] Where n = 1, 2, 3, ..., Called the fundamental frequency.

[0047] Therefore, in step 12, an integer multiple of the fundamental frequency, that is, the Nth harmonic frequency, can be used as the specific frequency point.

[0048] Step 13: Use the constructed clutter reference signal and the original time domain signal as input parameters of the adaptive filter to extract the clutter signal in the original time domain signal.

[0049] The adaptive filtering algorithm of the present application may use, for example, the Wiener filtering algorithm.

[0050] Step 14: Finally, the clutter signal output by the filter in the previous step is subtracted from the original time domain signal to obtain the first target signal after the clutter is eliminated.

[0051] As a further optimized embodiment of the present application, before the above steps, a frequency domain analysis is performed on the a priori target signal to obtain the value of a specific frequency point.

[0052] Figure 2 is the phase variation of power frequency harmonic signal over time, Figure 3 The phase of the target signal changes with time. In order to detect the target of a single-channel aliasing signal, it is necessary to first analyze the collected electromagnetic signal for a long time to obtain a priori knowledge of the power grid harmonic signal and the target signal. Through long-term analysis and testing of single-channel electromagnetic signals, it is shown that the power grid harmonics have the characteristics of slow change, and the corresponding characteristic frequency signal phase changes nonlinearly with slow time; while the characteristic frequency of the target signal is very stable, and the corresponding characteristic frequency signal phase changes linearly or remains unchanged with slow time. Figure 2 , Figure 3 The results of continuous observation of background clutter signals and target signals for 6 hours respectively. It can be seen from the figure that the phase of the background clutter signal changes nonlinearly over time, indicating that its frequency stability is poor, while the phase of the target signal changes approximately linearly over time, indicating that its frequency stability is high. Since the target signal shows a highly stable characteristic relative to the power grid harmonic signal, if the amplitude and frequency of a signal are slowly changing or stable, it can be regarded as a single-frequency signal at each time point or within a period of time, which is also the basis for constructing the target reference signal.

[0053] Step 12 is described in further detail below.

[0054] The power frequency fundamental wave and the target signal have nothing to do with each other. The method of the present application extracts the power frequency fundamental wave part of the obtained single-channel aliased time domain signal in order to cancel the part of the clutter that overlaps with the target signal. In step 12, the time domain power frequency fundamental wave signal is a set signal, or the time domain power frequency fundamental wave signal is generated by filtering the original time domain signal.

[0055] The time domain power frequency fundamental wave signal is a setting signal, for example, the test waveform of odd harmonics can be expressed as:

[0056]

[0057] By expanding the above formula in Fourier series, we can get:

[0058]

[0059] in:

[0060]

[0061] By rearranging formula (6), we can get:

[0062] I(t)=a k sin(Kωt+O) (9)

[0063] Among them, a k is the amplitude of the odd harmonic, K determines the harmonic order of the odd harmonic, O is the initial phase, and they are all constants, I b It represents the maximum value of the current, not the effective value. It can be seen from formulas (7) to (9) that harmonic signals of different orders in the power grid have a strong correlation. Therefore, the clutter reference signal can be constructed by moving the power frequency fundamental signal. It should be noted that under the specific power frequency fundamental signal condition of formula (6) of the present application, the specific frequency point is an odd multiple of the fundamental frequency of the time domain power frequency fundamental signal.

[0064] The time domain power frequency fundamental wave signal is generated by filtering the original time domain signal. Figure 4 This is a flow chart of an embodiment based on real-time extraction of the power frequency fundamental wave, wherein step 12 further includes steps 12A-C.

[0065] Step 11: receiving a signal transmitted along the power grid for sampling to generate an original time domain signal;

[0066] Step 12A, performing FFT on the obtained time domain signal to extract the power frequency fundamental wave part of the signal;

[0067] First, perform FFT on the obtained time domain signal to extract the power frequency fundamental wave part of the signal:

[0068] FFT(s(t))=FFT(s1(t)+n(t))=FFT(s1(t)+s2(t)+n'(t)) (10)

[0069] Set all spectrum components except the spectrum of the power frequency fundamental signal to zero to obtain FFT (s2 (t)).

[0070] Step 12B, perform IFFT on the obtained power frequency fundamental wave spectrum to obtain a time domain power frequency fundamental wave signal; perform IFFT on the obtained power frequency fundamental wave spectrum to obtain a time domain power frequency fundamental wave signal:

[0071] s2(t)=IFFT(FFT(s2(t))) (11)

[0072] Step 12C: Carrier modulate the time domain power frequency fundamental signal, move it to a specific frequency point, and construct a clutter reference signal;

[0073] The signal is then carrier modulated to move the power frequency fundamental signal to a specific frequency point to construct a clutter reference signal:

[0074] S refer =s2(t)A(cos(ω1 t)+cos(ω2 t)) (12)

[0075] It should be noted that, in the embodiment of formula (12), there are two specific frequency points, namely ω1 and ω2, which are determined by the location of the target signal.

[0076] Step 13 uses the constructed clutter reference signal and the original time domain signal as input parameters of the adaptive filter to extract the clutter signal in the original time domain signal;

[0077] Step 14: Finally, the clutter signal output by the filter in the previous step is subtracted from the original time domain signal to obtain a signal after clutter cancellation.

[0078] Figure 5 This is an adaptive filter structure constructed according to the clutter characteristics. It can be seen that the filter structure can be changed accordingly according to the characteristics of the clutter distribution, which also illustrates the feasibility of the spectrum shifting method.

[0079] Figure 6 This is the flow chart of the Wiener filter algorithm.

[0080] The adaptive filtering algorithm used in the present invention is the Wiener filtering algorithm. The implementation principle of the Wiener filtering algorithm is to design an impulse response function h to filter the observed signal sequence X so that the minimum square sum between it and the expected signal S reaches the minimum value. Assuming that the length of the signal S is N, the subscript starts from 0. For the filter h, the filtering process is as follows:

[0081] The estimated value of the signal at time n:

[0082]

[0083] The goal of the Wiener filter is as follows:

[0084]

[0085] Derivative the above formula, we get the minimum condition:

[0086]

[0087] Arranging the above formula and combining the properties of the related functions, we can get:

[0088] E[s(n)x(ni)]=R sx (-i) = R xs (i) (16)

[0089] E[h(m)x(nm)*x(ni)]=h(m)E[x(nm)*x(ni)]=h(m)R xx (mi) (17)

[0090]

[0091] For a filter h of length N, we have:

[0092]

[0093] Simplifying the above formula, we get:

[0094]

[0095] Among them, R XX is a symmetric matrix with all diagonal elements being R xx (0).

[0096] Figure 7 This is a spectrum comparison diagram before and after clutter cancellation. It is a spectrum comparison diagram before and after clutter cancellation based on measured data, which illustrates the effectiveness of this method for background clutter suppression.

[0097] Figure 8 This is a flow chart of another embodiment of the method of the present application.

[0098] The embodiment of the present invention also proposes a filtering method for a single-channel aliasing signal of a power grid harmonic. For the target signal purification method, first, based on the fact that the target signal has a relatively stable frequency at a specific frequency point and exhibits a narrowband single-frequency characteristic, a target reference signal is constructed using a sinusoidal signal; then the constructed target reference signal and the original time domain signal are used as input parameters of the adaptive filter to directly obtain the signal after the target signal is purified. Specifically, the following steps 21 to 22 are included:

[0099] Step 21: construct one or more single-frequency signals at the specific frequency point as target reference signals.

[0100] The first thing to do is to construct a target reference signal based on the target characteristics. We know that if the amplitude and frequency of a signal are slowly changing or stable, it can be regarded as a single-frequency signal at each time point or over a period of time. Therefore, the construction of the target reference signal is as follows:

[0101] S refer =A(cos(ω1 t)+cos(ω2 t)) (21)

[0102] It should be noted that, in the embodiment of formula (13), there are two specific frequency points, namely ω1 and ω2, which are determined by the location of the target signal.

[0103] Step 22: Use the target reference signal and the original time domain signal as input parameters of an adaptive filter to extract a second target signal from the original time domain signal.

[0104] The constructed target reference signal and the original time domain signal are used as the input parameters of the adaptive filter to directly obtain the signal after the target signal is purified. Fig. 9 (a)~(b) are the spectrum comparison diagrams before and after the target signal is purified. They are the spectrum comparison diagrams before and after the target signal is purified based on the measured data, which also illustrate the effectiveness of this method for background clutter suppression.

[0105] Furthermore, based on steps 11 to 14 and 21 to 22, at least one of the following steps 23 to 25 may be included.

[0106] Step 23: Compare the features of the first target signal and the second target signal and / or perform weighted superposition.

[0107] The features of the first target signal and the second target signal are compared, including peak amplitude comparison and / or peak frequency comparison; and weighted superposition is performed on the two, including weighted superposition of amplitude values ​​and / or weighted superposition of peak frequencies.

[0108] Step 24: adjust the fundamental frequency and / or waveform of the time-domain power frequency fundamental wave so that the difference between the first target signal and the second target signal is less than a set threshold.

[0109] In step 24, when the time domain power frequency fundamental wave signal is a set signal, the fundamental wave frequency and / or waveform is adjusted to change the calculation result. When the difference decreases, the difference between the fundamental wave frequency and / or waveform and the real power frequency fundamental wave signal decreases.

[0110] Step 25: Adjust the peak frequency of the target reference signal so that the difference between the first target signal and the second target signal is less than a set threshold.

[0111] In step 25, when constructing a target reference signal with the help of prior knowledge, the number of frequency points and the frequency value of the target reference signal affect the calculation result, and the number of frequency points and the frequency value of the target reference signal are adjusted to change the calculation result. When the difference decreases, the difference between the number of frequency points and the frequency value of the target reference signal and the true target signal decreases.

[0112] In steps 24 to 25, the difference between the first target signal and the second target signal may be, for example, the difference between the peak amplitude of the first target signal and the peak amplitude of the second target signal; for example, it may be the difference between the peak frequency of the first target signal and the peak frequency of the second target signal; for example, it may also be a weighted combination of the peak amplitude difference and the peak frequency difference between the first target signal and the second target signal.

[0113] When the time-domain industrial frequency fundamental wave signal is a set signal and / or a target reference signal is constructed with the aid of prior knowledge, an optimal calculation result is obtained by cyclically implementing at least one of steps 24 to 25. The optimal calculation result may, for example, include an optimal value of the set time-domain industrial frequency fundamental wave signal, an optimal value of the constructed target reference signal, or a result of weighted superposition of the features of the first target signal and the second target signal.

[0114] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0115] Therefore, the present application also proposes a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the method described in any embodiment of the present application is implemented.

[0116] Furthermore, the present application also proposes an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the method described in any embodiment of the present application when executing the computer program.

[0117] The present invention provides a filtering method for a single-channel aliased signal of power grid harmonics, and proposes two technical solutions respectively. The first technical solution starts from the clutter characteristics and adopts the method of clutter cancellation. The second technical solution starts from the target signal characteristics and adopts the method of target signal purification. For the clutter cancellation method, firstly, the received time domain signal is subjected to FFT, the power frequency fundamental wave part of the signal is extracted, and the clutter reference signal is constructed by shifting the spectrum of the power frequency fundamental wave signal, and then the constructed clutter reference signal and the original time domain signal are used to cancel through an adaptive filter to obtain a signal after the clutter is cancelled. For the target signal purification method, firstly, a target reference signal is constructed according to the target characteristics, and then the constructed target reference signal and the original time domain signal are purified through an adaptive filter to directly obtain the signal after the target signal is purified. The two technical solutions proposed by the present invention overcome the defect that adaptive filtering cannot be performed in the existing algorithm due to insufficient number of channels. It has been verified by experiments that both methods can effectively filter out most of the background clutter, and provide a solution for the detection of single-channel target signals contaminated by power grid harmonics.

[0118] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0119] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0120] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0121] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0122] The memory may include non-permanent storage in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0123] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0124] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A method for filtering a single-channel aliased signal of a power grid harmonic, characterized in that: The following steps are involved: Receive power grid radiation signals, perform sampling, and generate original time domain signals; Carrier modulate the time domain power frequency fundamental wave, move the time domain power frequency fundamental wave to a specific frequency point, and construct a clutter reference signal; The constructed clutter reference signal and the original time domain signal are used as input parameters of the adaptive filter to extract the clutter signal in the original time domain signal; Subtract the clutter signal output by the filter in the previous step from the original time domain signal to obtain the first target signal after the clutter is eliminated; According to the target characteristics, construct one or more single frequency signals of the specific frequency point as target reference signals; Using the target reference signal and the original time domain signal as input parameters of an adaptive filter, and extracting a second target signal from the original time domain signal; And at least 1 of the following steps: Comparing and / or performing weighted superposition on features of the first target signal and the second target signal; Adjusting the fundamental frequency and / or waveform of the time-domain power frequency fundamental wave so that the difference between the first target signal and the second target signal is less than a set threshold; The peak frequency of the target reference signal is adjusted so that the difference between the first target signal and the second target signal is less than a set threshold.

2. The method for filtering a single-channel aliased signal of a power grid harmonic according to claim 1, characterized in that: The time-domain industrial frequency fundamental wave signal is generated by filtering the original time-domain signal.

3. The filtering method for a single-channel aliased signal of a power grid harmonic according to claim 1, characterized in that: The time-domain industrial frequency fundamental wave signal is a setting signal.

4. The method for filtering a single-channel aliased signal of a power grid harmonic according to claim 1, characterized in that: The specific frequency point is an odd multiple of the fundamental frequency of the time domain industrial frequency fundamental signal.

5. The method for filtering a single-channel aliased signal of a power grid harmonic according to claim 1, characterized in that: The specific frequency point is one or more.

6. The filtering method for a single-channel aliased signal of a power grid harmonic according to claim 1, characterized in that: Prior to the step, a frequency domain analysis is performed on the a priori target signal to obtain the value of a specific frequency point.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 6 is implemented.

8. An electronic device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

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