Hanning self-multiplying convolution window FFT tri-spectrum line interpolation harmonic analysis method

Abstract

The invention provides a Hanning self-multiplying convolution window FFT tri-spectrum line interpolation harmonic analysis method. The method comprises the steps that 1, a voltage signal and a currentsignal are acquired according to the sampling frequency; 2, a Hanning self-multiplying convolution window function is applied to the voltage signal and the current signal separately, and FFT transform is conducted on the voltage signal and the current signal to obtain a corresponding voltage spectrum and a corresponding current spectrum; 3, maximum spectrum lines at detected peaks of fundamentalwaves and harmonic waves of the voltage spectrum and the current spectrum and amplitude values of two spectrum lines adjacent to each maximum spectrum line are detection separately; 4, amplitude values, phases and frequencies of the fundamental waves and the harmonic waves of the voltage spectrum and the current spectrum are calculated; and 5, electric energies and a total electric energy of the fundamental waves and the harmonic waves of the voltage spectrum and the current spectrum are calculated. According to the Hanning self-multiplying convolution window FFT tri-spectrum line interpolation harmonic analysis method, the calculation precision on the electric energy of the fundamental waves and the harmonic waves can be improved, and the calculation stability of an electric energy measurement algorithm can be improved.

Description

technical field [0001] The invention relates to the field of harmonic detection in power systems, in particular to a Hanning self-multiplied convolution window FFT trispectrum interpolation harmonic analysis method. Background technique [0002] As more and more nonlinear dynamic power loads such as electrified railways and electric arc furnaces are put into use, a large number of power harmonics are generated in the power supply grid, resulting in distortion of the current and voltage waveforms of the power grid. The existence of these disturbances not only leads to the deterioration of the power quality of the power supply, endangers the safe and stable operation of the power supply system, but also affects the accuracy of power metering. [0003] In order to accurately measure the fundamental wave and harmonic electric energy, the amplitude, frequency and phase parameters of the fundamental wave and each harmonic in the grid voltage and current signals should be accuratel...

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Problems solved by technology

[0004] Since the spectral performance of the window function is fixed, when the windowing interpolation correction algorithm is performed on the dynamic signal, the calculation accuracy is limited by the fixed sidelobe performance of the window function, resulting in the harmonic components in the measured signal being affected by the spectral leakage. cannot be accurately extracted;

[0005] Among the four types of interpolation correction algorithms, the correction formula of the single-peak spectral line interpolation correction algorithm is more complicated and is easily affected by spectrum leakage; the double-peak spectral line interpolation correction algorithm does not fully utilize the leaked spectral line information near the peak frequency point, and the calculation accuracy is relatively low. Poor; the four-peak spectral line interpolation correction algorithm has the highest calculation accuracy, but the calculation amount is also the largest

[0006] The Hanning window has been widely used due to its simple expression form, but the calculation accuracy of analyzing harmonics is not high enough

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