A method, device and equipment for filtering narrow-band interference of partial discharge signals and a storage medium

Abstract

The embodiment of the present specification provides a narrow-band interference filtering method, device and equipment of a partial discharge signal, and a storage medium. The method comprises: performing frequency slice wavelet transform on the partial discharge signal to obtain a frequency slice wavelet time-frequency spectrum; dividing the time-frequency spectrum according to frequency to obtain a sub-region containing narrow-band interference signals but not containing partial discharge pulses; calculating the narrow-band interference frequency of each sub-region; performing fast Fourier transform to obtain a partial discharge signal spectrum; filtering the narrow-band interference signals in the spectrum according to the narrow-band interference frequency; and performing inverse fast Fourier transform on the spectrum filtered of the narrow-band interference signals to reconstruct the partial discharge signal filtered of the narrow-band interference signals. The embodiment of the present specification achieves the purpose of effectively filtering the narrow-band interference in the partial discharge signal.

Description

Technical Field

[0001] The embodiments in this specification relate to the field of partial discharge signal technology, and more specifically, to a method, apparatus, device, and storage medium for narrowband interference filtering of partial discharge signals. Background Technology

[0002] Partial discharge signals can effectively assess the insulation status of electrical equipment. However, the environment in which partial discharge signals are acquired is often complex, with various forms of electromagnetic interference. Among these, narrowband interference has a significant impact on partial discharge signals. It is characterized by its long duration and high frequency, easily interfering with the insulation status detection of electrical equipment.

[0003] Currently, various methods exist for filtering narrowband interference in partial discharge signals, such as digital filtering, wavelet filtering, and empirical mode decomposition (EMD) denoising. However, these methods are still insufficient to effectively filter out narrowband interference in partial discharge signals, thus further improvements are needed. Summary of the Invention

[0004] This specification provides a method, apparatus, device, and storage medium for filtering narrowband interference in partial discharge signals. By improving the narrowband interference filtering method, narrowband interference in partial discharge signals can be effectively filtered out.

[0005] To achieve the above objectives, embodiments of this specification provide a method for narrowband interference filtering of partial discharge signals, comprising:

[0006] Acquire partial discharge signals;

[0007] The acquired partial discharge signal is subjected to frequency slice wavelet transform to obtain the time-spectrum diagram of the frequency slice wavelet transform;

[0008] The frequency slice wavelet transform time-spectrum diagram is divided according to frequency to obtain sub-regions that contain narrowband interference signals but do not contain partial discharge pulses;

[0009] Calculate the narrowband interference frequency for each sub-region;

[0010] The acquired partial discharge signal is subjected to a fast Fourier transform to obtain the partial discharge signal spectrum.

[0011] Narrowband interference signals in the partial discharge signal spectrum are filtered out based on the calculated narrowband interference frequencies of each sub-region.

[0012] A fast inverse Fourier transform is performed on the spectrum of the partial discharge signal after filtering out narrowband interference signals to reconstruct the partial discharge signal after filtering out narrowband interference signals.

[0013] To achieve the above objectives, embodiments of this specification also provide a narrowband interference filtering device for partial discharge signals, comprising:

[0014] The acquisition unit is used to acquire partial discharge signals;

[0015] The frequency slice wavelet transform unit is used to perform frequency slice wavelet transform on the acquired partial discharge signal to obtain the frequency slice wavelet transform time-spectrum diagram.

[0016] The division unit is used to divide the frequency slice wavelet transform time-spectrum diagram according to frequency, and obtain multiple sub-regions containing narrowband interference signals but not partial discharge pulses;

[0017] The calculation unit is used to calculate the narrowband interference frequency of each sub-region; the Fourier transform unit is used to perform a fast Fourier transform on the acquired partial discharge signal to obtain the partial discharge signal spectrum.

[0018] The filtering unit is used to filter out narrowband interference signals in the partial discharge signal spectrum diagram based on the calculated narrowband interference frequencies of each sub-region.

[0019] The inverse transform unit is used to perform a fast inverse Fourier transform on the spectrum of the partial discharge signal after filtering out narrowband interference signals, and reconstruct the partial discharge signal after filtering out narrowband interference signals.

[0020] To achieve the above objectives, embodiments of this specification also provide a computer device, including: a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the narrowband interference filtering method for partial discharge signals according to embodiments of this specification.

[0021] To achieve the above objectives, embodiments of this specification also provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the narrowband interference filtering method for partial discharge signals according to embodiments of this specification.

[0022] As can be seen from the above, in the embodiments of this specification, the frequency slice wavelet transform time-spectrum diagram is divided according to frequency to obtain sub-regions that contain narrowband interference signals but do not contain partial discharge pulses. The narrowband interference frequency of each sub-region is calculated, and the narrowband interference signal in the partial discharge signal spectrum diagram is filtered out according to the calculated narrowband interference frequency of each sub-region, thus effectively filtering out the narrowband interference signal in the partial discharge signal spectrum diagram. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. The drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a flowchart of a narrowband interference filtering method for partial discharge signals in the embodiments of this specification;

[0025] Figure 2 This is a flowchart of the method for obtaining the time-spectrum graph of frequency slice wavelet transform in the embodiments of this specification;

[0026] Figure 3 This is a schematic diagram of the partial discharge pulse signal in the embodiments of this specification;

[0027] Figure 4 This is a schematic diagram of narrowband interference signals in the embodiments of this specification;

[0028] Figure 5 This is a schematic diagram of a partial discharge signal containing narrowband interference in an embodiment of this specification;

[0029] Figure 6 This is a time-spectrum diagram of frequency slice wavelet transform in the embodiments of this specification;

[0030] Figure 7 This is a schematic diagram of the partial discharge signal reconstructed after frequency slice wavelet transform in the embodiments of this specification;

[0031] Figure 8 This is a schematic diagram of a narrowband interference filtering device for partial discharge signals in the embodiments of this specification;

[0032] Figure 9 This is a schematic diagram of the frequency slice wavelet transform unit in the embodiments of this specification. Detailed Implementation

[0033] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the embodiments of this specification.

[0034] It should be understood that the embodiments of this application and the specific features in the embodiments are detailed descriptions of the technical solutions of this application, rather than limitations on the technical solutions of this application. Unless otherwise specified, the embodiments of this application and the technical features in the embodiments can be combined with each other.

[0035] Example 1

[0036] This specification provides a method for narrowband interference filtering of partial discharge signals. Please refer to the embodiments below. Figure 1 The flowchart shown illustrates that the embodiment may include the following steps:

[0037] Step S1: Acquire partial discharge signals;

[0038] In some embodiments, the narrowband interference signal can be a periodic, long-duration, and high-frequency electromagnetic interference signal. The narrowband interference signal can be composed of multiple superimposed narrowband interference signals with different frequencies and amplitudes. In the time domain, the narrowband interference can be a high-frequency sine wave or cosine wave. In the frequency domain, the narrowband interference can be discretely distributed spectral lines with different frequencies. The main sources of the narrowband interference can be high-frequency protection communication signals, radio interference signals, etc.

[0039] For example, please see Figure 4 As shown, a narrowband interference signal is simulated by superimposing six sine functions with different amplitudes and frequencies. The frequency range of the narrowband interference signal is 0.9MHz to 10MHz.

[0040] The partial discharge signal may consist only of narrowband interference signals, or only of partial discharge pulse signals, or may include a superposition of narrowband interference signals and partial discharge pulse signals. The partial discharge pulse signal may be a pulse signal generated by discharge in a localized region of the insulator. The partial discharge pulse signal may be an important signal indicating insulation degradation of the insulator.

[0041] For example, please see Figure 3 The image shows four partial discharge pulse signals simulated using models of a single exponentially decaying pulse, a double exponentially decaying pulse, a single exponentially oscillating decaying pulse, and a double exponentially oscillating decaying pulse. Please refer to [link to relevant documentation]. Figure 5 As shown, this is a partial discharge signal, which includes a superimposed signal of four partial discharge pulse signals and a narrowband interference signal.

[0042] In some embodiments, partial discharge signals can be acquired at a certain sampling frequency to obtain partial discharge signals with a certain number of acquisition points. The partial discharge signals can be a row matrix arranged in the order of acquisition time.

[0043] For example, as shown in Figure 5, the partial discharge signal has a sampling frequency of f = 50 MHz and a sampling point count of n = 2500. The partial discharge signal can be a 1×n = 1×2500 matrix.

[0044] Step S2: Perform frequency slice wavelet transform on the acquired partial discharge signal to obtain the frequency slice wavelet transform time-spectrum diagram;

[0045] In some embodiments, the frequency slice wavelet transform time-spectrum diagram can clearly describe the relationship between the frequency of the partial discharge signal and time, and the amplitude of the partial discharge signal can be represented by the color intensity.

[0046] For example, please see Figure 6 The image shows a time-spectrum diagram of a frequency slice wavelet transform. The horizontal axis represents time, and the vertical axis represents frequency. Different colors represent the amplitude of the signal.

[0047] In some embodiments, the frequency slice wavelet transform allows the partial discharge signal to be described simultaneously in both the time and frequency domains. Specifically, the frequency slice wavelet transform can be expressed by the following formula:

[0048]

[0049] Among them, W f (t, w, k) can be a signal with time t and frequency w, where w can be any frequency in the frequency matrix, and t can be any time during signal acquisition. The W... f (t, w, k) can be in complex form. u is the estimated frequency; For the Fourier transform of signal f(t), It is a frequency slicing function, the stated yes The Fourier transform of , where "*" indicates conjugate, and k is the time-frequency resolution coefficient.

[0050] In some embodiments, please refer to Figure 2 As shown, step 2 may include:

[0051] Step 21: Determine the frequency matrix based on the frequency slice range and frequency interval;

[0052] Specifically, the frequency matrix can be a row vector 1×m in which frequencies are arranged in ascending order according to frequency intervals. The frequency slice range can be determined based on the sampling frequency. The frequency slice range can be 0 to f / 2. The frequency interval can be determined based on the sampling frequency and the number of sampling points. The frequency interval can be f / n. The frequencies in the frequency matrix and the number of columns m in the frequency matrix can be determined based on the frequency slice range and the frequency interval.

[0053] For example, the frequency slice range can be 0–25 MHz, the frequency interval can be 20,000, and the number of columns m in the 1×m frequency matrix can be [(f / 2)×n / f] = [(50 / 2)×2500 / 50] = 1250. The frequencies in the 1×m = 1×1250 frequency matrix are 0 Hz, 20,000 Hz, 40,000 Hz, 60,000 Hz…25 MHz.

[0054] Step 22: Obtain the complex matrix of frequency slice wavelet transform based on the partial discharge signal, frequency slice function, and frequency matrix;

[0055] Specifically, the frequency slicing function can be a symmetric function in both the time and frequency domains, and the highest amplitude points can be concentrated at the center of the time-frequency surface. The frequency slicing function can take... Its time-domain expression can be The frequency slicing function It can have the best time-frequency aggregation.

[0056] Furthermore, to ensure the accuracy of the frequency slice wavelet transform, relevant scaling parameters are introduced. These scaling parameters may include frequency resolution η and time-frequency resolution coefficient k. The frequency resolution can be expressed as the accuracy of describing the partial discharge signal in the frequency domain. The time-frequency resolution coefficient k can control the sensitivity of frequency or time, achieving a balance between time and frequency resolution.

[0057] For example, the frequency resolution can be 0.005≤η≤0.55, and the time-frequency resolution coefficient k can be k=0.707η.

[0058] Based on the partial discharge signal f(t) and the frequency slice function Given the frequency matrix, after performing a frequency slice wavelet transform, the signal W corresponding to (t, w) can be calculated. f (t,w,k).

[0059] The frequency slice wavelet transform complex matrix can be an n×m matrix. The rows of the frequency slice wavelet transform complex matrix can correspond to time, and the columns can correspond to frequencies. The elements in the row corresponding to time t and the column corresponding to frequency w in the frequency slice wavelet transform complex matrix can be W. f (t, w, k). Furthermore, each column of the frequency slice wavelet transform complex matrix corresponds one-to-one with the frequency of each column in the frequency matrix.

[0060] For example, the partial discharge signal is a 1×2500 matrix. After frequency slice wavelet transform calculation, 2500×1250 signals W are obtained. These 2500×1250 signals W can be placed as 2500×1250 elements in a 2500×1250 frequency slice wavelet transform complex matrix. Each column of the 2500×1250 frequency slice wavelet transform complex matrix corresponds one-to-one with the frequency of the 1×1250 frequency matrix. Specifically, the 5th column of the frequency slice wavelet transform complex matrix corresponds to a frequency of 80000Hz in the frequency matrix. The element of the 5th column is W. f (t, 80000, k).

[0061] Step 23: Draw the time-spectrum diagram of the frequency slice wavelet transform based on the modulus of each element in the complex matrix of the frequency slice wavelet transform.

[0062] Specifically, based on the moduli of the elements in different rows and columns of the frequency slice wavelet transform complex matrix, the amplitude characteristics of signals at different times and frequencies corresponding to the time-spectrum diagram of the frequency slice wavelet transform can be obtained. Based on the changes in these amplitude characteristics in the time-frequency region, the time-spectrum diagram of the frequency slice wavelet transform can be plotted.

[0063] Step S3: Divide the frequency slice wavelet transform time-spectrum diagram according to frequency to obtain sub-regions that contain narrowband interference signals but do not contain partial discharge pulses;

[0064] In some embodiments, the narrowband interference signal may be a superposition of multiple narrowband interferences at different frequencies. The frequency slice wavelet transform time-spectrum may include multiple narrowband interference spectral lines. Different narrowband interference spectral lines may correspond to different frequencies.

[0065] Based on the characteristics of narrowband interference signals in the frequency slice wavelet transform time-spectrum diagram, the multiple narrowband interference spectral lines can be determined in the frequency slice wavelet transform time-spectrum diagram.

[0066] For details, please refer to Figure 6 As shown, the narrowband interference has a fixed frequency and spans the entire time interval, and the spectral line of each narrowband interference can be a rectangle spanning the entire time interval. The partial discharge pulse signal has a short duration, and the spectral line of each partial discharge signal spans the entire frequency range. Based on the characteristic that the narrowband interference spans the entire time interval and has a fixed frequency, the narrowband interference spectral line in the time-spectrum diagram can be determined.

[0067] Based on the narrowband interference spectral lines of different frequencies, the time-spectrum diagram of the frequency slice wavelet transform is divided to obtain multiple sub-regions containing narrowband interference.

[0068] For example, Figure 6Six narrowband interferences with different frequencies can be observed. A specific time period of the signal is selected and divided into six sub-regions.

[0069] Furthermore, the division of sub-regions directly affects the accuracy of narrowband interference frequency calculation. The frequency slice wavelet transform time-spectrum diagram can include a time-frequency region containing partial discharge pulse signals and a time-frequency region not containing partial discharge pulse signals. To ensure accurate narrowband interference frequency calculation in each sub-region, the multiple sub-regions containing narrowband interference can be multiple sub-regions containing narrowband interference signals but not containing partial discharge pulses.

[0070] Specifically, based on the generation principle of narrowband interference, when the local discharge signal acquisition environment is relatively stable, the energy amplitude of the narrowband interference can also be relatively stable. The partial discharge pulse signal can be a short-duration pulse signal. Based on the frequency slice wavelet transform time-spectrum diagram, sub-regions containing narrowband interference signals but not partial discharge pulses can be easily distinguished.

[0071] For example, please see Figure 6 As shown, 0.5–1MHz, 1–1.5MHz, 3.5–4.5MHz, 4.5–5.5MHz, 7.5MHz–9MHz, and 9–1.1MHz correspond to six narrowband interference spectral lines at different frequencies. (Time axis 1×10⁻⁶) -5 s,2×10 -5 s,3×10 -5 s,4×10 -5 The region near s contains partial discharge pulse signals. The remaining region contains narrowband interference but not partial discharge pulses. Based on six narrowband interference spectral lines of different frequencies, six sub-regions are obtained within the region containing narrowband interference but not partial discharge pulses.

[0072] Step S4: Calculate the narrowband interference frequency of each sub-region;

[0073] In some embodiments, the sub-regions correspond to sub-matrices in the frequency slice wavelet transform complex matrix; the frequencies of narrowband interference in different sub-regions are determined based on the corresponding sub-matrices.

[0074] Specifically, a sub-region can correspond to a time range and a frequency range in the frequency slice wavelet transform time-spectrum. Different rows of the frequency slice wavelet transform complex matrix can correspond to different times, and different columns of the frequency slice wavelet transform complex matrix can correspond to different frequencies. Based on the time range and frequency range, the elements of the corresponding rows and columns in the complex matrix are extracted to obtain the sub-matrix corresponding to the sub-region.

[0075] Furthermore, the narrowband interference frequency of the corresponding sub-region is determined based on the weighted average of the maximum frequency in each row of the sub-matrix, wherein the frequency of the narrowband interference in each sub-region is:

[0076]

[0077] Among them, f k f is the frequency of the k-th sub-region. i q represents the frequency corresponding to the maximum value in the i-th row of the corresponding submatrix. i For frequency f i The corresponding row number in the submatrix, n f Let i be the total number of rows in the submatrix, i = 1, 2, ..., n f .

[0078] Specifically, the frequency f corresponding to the maximum value in each row i The expression is as follows:

[0079] f i = Frequency interval × Number of columns in the wavelet transform complex matrix corresponding to the frequency slice.

[0080] For example, Figure 6 A sub-region corresponds to rows 1-500 and columns 44-48 of a 2500×1250 frequency slice wavelet transform complex matrix. Elements from rows 1-500 and columns 44-48 of the 2500×1250 complex matrix are extracted to generate the corresponding submatrix. The submatrix has a total of n elements. f =500 rows. Multiply the maximum frequency value of the first row in the 500th row of the submatrix by 1, the maximum frequency value of the second row by 2, and so on until the maximum frequency value of the 500th row is multiplied by 500, and then divided by the total number of rows 500, to obtain the narrowband interference frequency of this sub-region as 0.9MHz.

[0081] Step S5: Perform a Fast Fourier Transform on the acquired partial discharge signal to obtain the partial discharge signal spectrum.

[0082] In some embodiments, a Fast Fourier Transform (FFT) can be performed on the partial discharge signal. The FFT can quickly convert the partial discharge signal in the time domain into a signal in the frequency domain, thereby obtaining the amplitude characteristics of the partial discharge signal at different frequency values. The horizontal axis of the partial discharge signal spectrum can represent frequency, and the vertical axis can represent amplitude.

[0083] Specifically, performing a Fast Fourier Transform on the partial discharge signal yields a complex matrix containing the amplitude characteristics of the partial discharge signal. The elements of this complex matrix include amplitude characteristics corresponding to frequencies. The spectrum of the partial discharge signal can then be obtained from this complex matrix.

[0084] For example, after performing a Fast Fourier Transform on the 1×2500 matrix of partial discharge signals acquired in step S1, a 1×2500 matrix A is obtained, where the elements of matrix A include the signal amplitude. A sampling rate frequency f = 50MHz is then placed within a 1×2500 matrix B at frequency intervals of 20000. The elements in matrix A correspond one-to-one with the elements in matrix B. Using the elements in matrix B as the x-axis and the corresponding elements in matrix A as the y-axis, the partial discharge signal spectrum can be obtained.

[0085] Step S6: Filter out the narrowband interference signals in the partial discharge signal spectrum diagram based on the calculated narrowband interference frequencies of each sub-region;

[0086] In some embodiments, the amplitude corresponding to the narrowband interference frequency of each sub-region in the partial discharge signal spectrum is set to zero in order to filter out the narrowband interference in the partial discharge signal spectrum.

[0087] Specifically, the elements corresponding to the narrowband interference frequencies in the complex matrix obtained after performing the fast Fourier transform are set to zero.

[0088] For example, step S4 calculates the narrowband interference frequencies for each sub-region as 0.9MHz, 1.5MHz, 4MHz, 5MHz, 8.5MHz, and 10MHz. These frequencies (0.9MHz, 1.5MHz, 4MHz, 5MHz, 8.5MHz, and 10MHz) correspond to the 46th, 78th, 199th, 251st, 425th, and 500th columns of matrix B, respectively. The elements in matrix A corresponding to columns 46, 78, 199th, 251st, 425th, and 500 are then set to zero, resulting in a new matrix A1.

[0089] Step S7: Perform an inverse fast Fourier transform on the spectrum of the partial discharge signal after filtering out the narrowband interference signal to reconstruct and obtain the partial discharge signal after filtering out the narrowband interference signal;

[0090] The inverse fast Fourier transform can quickly convert the partial discharge signal in the frequency domain back to the time domain, and reconstruct the partial discharge signal after filtering out narrowband interference signals.

[0091] For example, performing an inverse fast Fourier transform on the new matrix A1 yields the partial discharge signal after filtering out narrowband interference. (See also...) Figure 7 As shown, the partial discharge signal after filtering out narrowband interference signals was reconstructed. The narrowband interference signals were effectively filtered out, and the four discharge signals were accurately restored.

[0092] This specification provides a method for filtering narrowband interference from partial discharge signals. The method involves performing a frequency slice wavelet transform on the acquired partial discharge signal to obtain a time-spectrum. The time-spectrum is then divided according to frequency to obtain multiple sub-regions containing narrowband interference signals but not partial discharge pulses. The narrowband interference frequency of each sub-region is calculated. A fast Fourier transform (FFT) is performed on the acquired partial discharge signal to obtain a partial discharge signal spectrum. Narrowband interference signals in the partial discharge signal spectrum are filtered out based on the calculated narrowband interference frequencies of each sub-region. Finally, an inverse fast Fourier transform (IFFT) is performed on the spectrum of the partial discharge signal after filtering out the narrowband interference signals to reconstruct the remaining partial discharge signal. This method effectively filters out narrowband interference from partial discharge signals.

[0093] Example 2

[0094] Please see Figure 8 This specification provides a narrowband interference filtering device for partial discharge signals, which can be used to implement the method described in Embodiment 1, and has the corresponding functional modules and beneficial effects for performing the method. The device specifically includes:

[0095] Acquisition unit 81 is used to acquire partial discharge signals;

[0096] The frequency slice wavelet transform unit 82 is used to perform frequency slice wavelet transform on the acquired partial discharge signal to obtain the frequency slice wavelet transform time-spectrum diagram.

[0097] The partitioning unit 83 is used to partition the frequency slice wavelet transform time-spectrum diagram according to the frequency to obtain a sub-region containing narrowband interference signals but not partial discharge pulses;

[0098] Calculation unit 84 is used to calculate the narrowband interference frequency of each sub-region;

[0099] Fourier transform unit 85 is used to perform fast Fourier transform on the acquired partial discharge signal to obtain the partial discharge signal spectrum.

[0100] The filtering unit 86 is used to filter out the narrowband interference signal in the partial discharge signal spectrum diagram according to the calculated narrowband interference frequency of each sub-region.

[0101] The inverse transform unit 87 is used to perform a fast inverse Fourier transform on the spectrum of the partial discharge signal after filtering out the narrowband interference signal, and reconstruct the partial discharge signal after filtering out the narrowband interference signal.

[0102] For further details, please refer to Figure 9 The frequency slice wavelet transform unit 82 includes:

[0103] Determining unit 91 is used to determine the frequency matrix based on the frequency slice range and frequency interval;

[0104] Unit 92 is used to obtain the frequency slice wavelet transform complex matrix based on the acquired partial discharge signal, frequency slice function and frequency matrix;

[0105] Drawing unit 93 is used to draw the time-spectrum diagram of the frequency slice wavelet transform based on the modulus of each element in the complex matrix of the frequency slice wavelet transform.

[0106] Furthermore, the filtering unit 86 includes:

[0107] The zeroing unit is used to set the amplitude corresponding to the narrowband interference frequency of each sub-region in the partial discharge signal spectrum diagram to zero.

[0108] Example 3

[0109] This specification provides a computer device, including: a memory, a processor, and a computer program stored in the memory. The processor executes the computer program to implement the steps of the narrowband interference filtering method for partial discharge signals described in Embodiment 1 of this specification.

[0110] The memory can be a read-only memory, a hard disk drive, a solid-state drive, or a USB flash drive, etc. The processor can be implemented as a central processing unit (CPU), an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field-programmable gate array (FPGA), a controller, a microcontroller, a microprocessor, or other electronic components.

[0111] The computer device provided in the embodiments of the present invention can execute the narrowband interference filtering method for partial discharge signals provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of executing the method.

[0112] Example 4

[0113] This specification provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the narrowband interference filtering method for partial discharge signals described in Embodiment 1 of this specification.

[0114] The computer-readable storage medium provided in the embodiments of the present invention can execute the narrowband interference filtering method for partial discharge signals provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of executing the method.

[0115] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable memories (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0116] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can 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, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0117] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0118] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the functions specified in one or more boxes. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A method for narrowband interference filtering of partial discharge signals, characterized in that, include: Acquire partial discharge signals; The acquired partial discharge signal is subjected to frequency slice wavelet transform to obtain the time-spectrum diagram of the frequency slice wavelet transform; The frequency slice wavelet transform time-spectrum diagram is divided according to frequency to obtain sub-regions that contain narrowband interference signals but do not contain partial discharge pulses; Calculate the narrowband interference frequency for each sub-region; The acquired partial discharge signal is subjected to a fast Fourier transform to obtain the partial discharge signal spectrum. Narrowband interference signals in the partial discharge signal spectrum are filtered out based on the calculated narrowband interference frequencies of each sub-region. A fast inverse Fourier transform is performed on the spectrum of the partial discharge signal after filtering out narrowband interference signals to reconstruct the partial discharge signal after filtering out narrowband interference signals. The step of performing frequency slice wavelet transform on the acquired partial discharge signal to obtain the time-spectrum diagram of the frequency slice wavelet transform includes: The frequency matrix is ​​determined based on the frequency slice range and frequency interval; Based on the partial discharge signal, frequency slice function, and frequency matrix, the complex matrix of frequency slice wavelet transform is obtained; Based on the modulus of each element in the complex matrix of the frequency slice wavelet transform, plot the time-spectrum diagram of the frequency slice wavelet transform; Each sub-region corresponds one-to-one with a submatrix in the frequency slice wavelet transform complex matrix, and the narrowband interference frequency of each sub-region is calculated using the following formula: ， in, f k For the first k Narrowband interference frequencies in each sub-region f i The frequency corresponding to the maximum value in the i-th row of the corresponding submatrix. q i For frequency f i The corresponding row number in the submatrix n f This represents the total number of rows in the submatrix. i=1,2,…,n f ; The step of filtering out narrowband interference signals in the partial discharge signal spectrum based on the calculated narrowband interference frequencies of each sub-region includes: Set the amplitude corresponding to the narrowband interference frequency of each sub-region in the partial discharge signal spectrum diagram to zero.

2. The method according to claim 1, characterized in that, The expression for the frequency slicing function is as follows: ， in, w For frequency, yes P(t) Fourier transform, P(t) It is the time-domain expression of the frequency slice function.

3. A narrowband interference filtering device for partial discharge signals, characterized in that, include: The acquisition unit is used to acquire partial discharge signals; The frequency slice wavelet transform unit is used to perform frequency slice wavelet transform on the acquired partial discharge signal to obtain the frequency slice wavelet transform time-spectrum diagram. The division unit is used to divide the frequency slice wavelet transform time-spectrum diagram according to frequency to obtain sub-regions that contain narrowband interference signals but do not contain partial discharge pulses; The calculation unit is used to calculate the narrowband interference frequency of each sub-region; The Fourier transform unit is used to perform a fast Fourier transform on the acquired partial discharge signal to obtain the partial discharge signal spectrum. The filtering unit is used to filter out narrowband interference signals in the partial discharge signal spectrum diagram based on the calculated narrowband interference frequencies of each sub-region. The inverse transform unit is used to perform a fast inverse Fourier transform on the spectrum of the partial discharge signal after filtering out narrowband interference signals, and reconstruct the partial discharge signal after filtering out narrowband interference signals. The frequency slice wavelet transform unit includes: The determining unit is used to determine the frequency matrix based on the frequency slice range and frequency interval; The acquisition unit is used to obtain the frequency slice wavelet transform complex matrix based on the acquired partial discharge signal, frequency slice function, and frequency matrix. The plotting unit is used to plot the time-spectrum diagram of the frequency slice wavelet transform based on the modulus of each element in the complex matrix of the frequency slice wavelet transform. The filtering unit includes: The zeroing unit is used to set the amplitude corresponding to the narrowband interference frequency of each sub-region in the partial discharge signal spectrum diagram to zero. Each sub-region corresponds one-to-one with a submatrix in the frequency slice wavelet transform complex matrix, and the narrowband interference frequency of each sub-region is calculated using the following formula: ， in, f k For the first k Narrowband interference frequencies in each sub-region f i The frequency corresponding to the maximum value in the i-th row of the corresponding submatrix. q i For frequency f i The corresponding row number in the submatrix n f This represents the total number of rows in the submatrix. i=1,2,…,n f .

4. A computer device, characterized in that, include: A memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method of claim 1 or 2.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps of the method described in claim 1 or 2.

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