Electric energy metering method based on Kaiser window FFT four-peak interpolation

Abstract

The invention discloses an electric energy metering method based on Kaiser window FFT four-peak interpolation. The electric energy metering method comprises steps that based on a Kaiser window FFT four-peak interpolation modification formula, FFT frequency shift, and frequency spectrum of a window function Kaiser, amplitudes of symmetrical spectral lines on left sides and right sides of fundamental wave, harmonic wave, and interharmonic wave peak value frequency points are acquired, and by using a polynomial fitting formula, the general amplitude, phase, and frequency interpolation modification formula of the signal fundamental waves, the harmonic waves, and the interharmonic waves is acquired; according to the general amplitude, phase, and frequency interpolation modification formula, the amplitude parameters, the phase parameters, and the frequency parameters of the fundamental waves, the harmonic waves, and the interharmonic waves of measured voltage signals and measured current signals are calculated; fundamental wave electric energy, harmonic wave electric energy, interharmonic wave electric energy, and total electric energy are calculated. The electric energy metering method is advantageous in that according to a four-peak interpolation modulation algorithm, by fully using the symmetrical performance of the left and right four spectral lines of the amplitude frequency points and the main lobe performance and the side lobe performance of the Kaiser window function, high calculation accuracy is provided.

Description

technical field [0001] The invention relates to the field of electric energy metering of a power supply system and the field of digital electric energy metering, in particular to an electric energy metering method based on Kaiser window FFT four-peak interpolation. Background technique [0002] As more and more non-linear dynamic power loads such as electrified railways, rolling mills, electric arc furnaces, electric vehicle charging piles, hoists, smart home appliances, and elevators are put into use, a large number of power harmonics and intermittent harmonic. A large number of interference components such as power harmonics, inter-harmonics, DC attenuation, and voltage drops have caused distortion of the current and voltage waveforms of the power grid. The existence of these disturbances not only seriously affects the power quality of the power supply, endangers the safe and stable operation of the power supply system, and even leads to serious power accidents, resulting...

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Problems solved by technology

[0007] However, these existing algorithms still have the following problems: 1) Since the spectral performance of the window function is fixed, when performing window interpolation correction algorithms on dynamic signals, the calculation accuracy is limited by the fixed sidelobe performance of the window function. As a result, the harmonic components in the measured signal cannot be accurately extracted due to the influence of spectrum leakage; 2) The single-peak spectral line interpolation correction formula is more complicated and is easily affected by spectrum leakage, and the double-peak spectral line algorithm has no effect on the spectrum contained near the peak frequency point. Insufficient use of line information, the three-peak spectral line algorithm does not consider the comprehensive information of the symmetrical spectral lines around the peak frequency point, and it is difficult to meet the requirements of high-precision electric energy measurement; 3) In the existing interpolation correction algorithm, even harmonic electric energy calculation is common The problem with poor accuracy

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