An improved flat-top self-convolution window weighted power harmonic amplitude estimation method

A power harmonic, self-winding technology, applied in computing, electrical digital data processing, instruments, etc., can solve the requirements of weak signal detection, low harmonic amplitude measurement accuracy, poor weak signal parameter estimation ability, etc. problem, to achieve the effect of reducing the fence effect error, fast sidelobe decay rate, easy to achieve

Active Publication Date: 2021-07-30
JIANGSU ELECTRIC POWER CO
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Problems solved by technology

However, the classic flat-top window function is limited by the side lobe performance and the flatness of the main lobe, and the measurement accuracy of the harmonic amplitude is not high, especially the parameter estimation ability for weak signals is poor, and it cannot meet the weak signal detection requirements of GB / T14549-1993 Require

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  • An improved flat-top self-convolution window weighted power harmonic amplitude estimation method
  • An improved flat-top self-convolution window weighted power harmonic amplitude estimation method
  • An improved flat-top self-convolution window weighted power harmonic amplitude estimation method

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Embodiment Construction

[0042] The invention as Figure 1-4 shown, including the following steps:

[0043] step 1):

[0044] Using an analog-to-digital converter at a fixed sampling frequency f s Sampling the grid signal to obtain sampled data x(n);

[0045] Step 2):

[0046] Construct an improved FDMS-4FT self-convolution window function f with length N pp (n), weighting the sampled data x(n) to obtain a long sequence of N points x N (n);

[0047] Step 3):

[0048] pair sequence x N (n) Perform fast Fourier transform operation to obtain frequency domain spectral line, and then calculate the modulus of the spectral line to obtain the fundamental wave and the amplitude of each harmonic of the signal.

[0049] The method of constructing the improved FDMS-4FT self-convolution window in step 2) is as follows:

[0050] First, optimize the FDMS-4FT window coefficients. Assuming a P-order FDMS-4FT convolution window f pp (n) has length N PP . due to N PP >>P≥1, the length of the parent window ...

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Abstract

An improved flat-top self-convolution window-weighted power harmonic amplitude estimation method. The FDMS-4FT window is selected as the parent window for time-domain self-convolution to obtain a new flat-top window function; compared with the traditional classic flat-top window function, the flat-top window has lower side lobe peak levels and faster Sidelobe decay rate. In order to make the new flat-top self-convolution window have a flatter main lobe while having excellent side lobe performance, the coefficients of the flat-top self-convolution window are optimized so that it has a flatter main lobe than the parent window. flap, thereby improving the accuracy of power harmonic amplitude estimation. When this window function is applied to the harmonic amplitude estimation of power system, it is not affected by fundamental frequency fluctuations, etc., and there is no need to correct the harmonic amplitude calculation results, and the amplitude measurement results can be obtained directly, with a small amount of calculation, and With high accuracy.

Description

technical field [0001] The invention belongs to the field of electric power harmonic detection, in particular to a method for detecting the harmonic amplitude of a power system based on windowed FFT. Background technique [0002] Harmonic analysis is an important task in power system signal processing. At present, researchers have proposed many methods for harmonic parameter estimation, which can be divided into time-domain and frequency-domain analysis methods. Time-domain methods mainly include two types of algorithms based on autocorrelation and linear prediction. The frequency domain method is a direct spectrum estimation method based on the discrete Fourier transform (Discrete Fourier Transform DFT). Compared with the time-domain method, the DFT method has a clear physical meaning, and has an FFT algorithm to improve the real-time performance of signal estimation, and has a small amount of calculation. It is currently the most widely used method for estimating harmoni...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F17/14
CPCG06F17/142
Inventor 王靓刘忠吴栋良王树刚卜扬李培培陈英传于凌玲
Owner JIANGSU ELECTRIC POWER CO
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