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Method for acquiring parameters of electric power harmonic waves by using Hanniing window function continuous frequency spectrum interpolation

A technology of power harmonics and Hanning window, applied in the field of power measurement and automation

Inactive Publication Date: 2012-01-25
CHINA UNIV OF MINING & TECH
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Problems solved by technology

Many scholars have effectively improved the accuracy of harmonic estimation by using the window interpolation method [1~6], but with the increase of the order of the interpolation correction curve fitting function and the increase of the number of harmonics , the accuracy of harmonic estimation is improved and the amount of calculation is greatly increased

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  • Method for acquiring parameters of electric power harmonic waves by using Hanniing window function continuous frequency spectrum interpolation
  • Method for acquiring parameters of electric power harmonic waves by using Hanniing window function continuous frequency spectrum interpolation
  • Method for acquiring parameters of electric power harmonic waves by using Hanniing window function continuous frequency spectrum interpolation

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Embodiment Construction

[0030] In order to achieve the above object, the implementation of the present invention can directly use a voltage divider or obtain the busbar voltage signal of the power grid from the secondary side of the voltage transformer PT, obtain the current signal from the current transformer CT, and send the signal sampling after appropriate signal conditioning Entrance.

[0031] Step a. Sampling the voltage or current of the power signal to be analyzed, and press figure 1 The process calculates its Chirp-Z Transform or CZT value , take a natural positive integer, and then calculate the fundamental wave parameters, amplitude, frequency and phase of the power signal by formula 1, formula 2 and formula 3;

[0032] Estimate the fundamental amplitude: Formula 1

[0033] Estimate the fundamental frequency value: f 1 =(θ+k’Ф) / 2 Formula 2

[0034] Estimate the fundamental phase value: Formula 3

[0035] In the above 3 formu...

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Abstract

The invention relates to a method for acquiring parameters of electric power harmonic waves by using Hanning window function continuous frequency spectrum interpolation, applicable to harmonic analysis and monitoring on voltage and current of a power network. Firstly, chirp Z transform (CZT) is utilized to accurately extract fundamental wave signal parameters (amplitude, frequency and phase) froman electric signal containing harmonic waves. Then the fundamental wave signal is subtracted from the analyzed electric signal and a Hanning window function is added to cut off the electric signal, and FFT (fast Fourier transformation) is utilized to calculate frequency spectrum of the residual signal. And then frequency values of all the harmonic waves are accurately calculated according to the frequency of a fundamental wave. And finally interpolation is carried out on the Hanning window function in the frequency domain according to each harmonic wave frequency, and the parameter of each electric power harmonic wave is accurately calculated. The method provided by the invention has estimated value accuracy basically equivalent to that of an addition Hanning window FFT bispectrum line interpolation fitting analysis method of electric power harmonic waves, and calculated amount of the method provided by the invention is about 1 / 2 of that of the addition Hanning window FFT bispectrum line interpolation fitting analysis method of electric power harmonic waves.

Description

technical field [0001] The invention relates to an analysis and automatic monitoring algorithm of grid voltage and current waveform distortion, which can be used for analysis instruments and automatic monitoring devices of various grid voltage and current waveform distortions. The utility model belongs to the technical field of electric power measurement and automation. Background technique [0002] With the development of power electronics technology and devices, nonlinear loads are more and more widely used in power systems, and harmonic pollution in power systems is becoming more and more serious. Harmonics have become the main problem affecting power quality. The high-precision estimation of harmonic component parameters will be beneficial to the evaluation of power quality and the corresponding necessary control measures. [0003] Fast Fourier Transform (FFT) is the fastest tool for harmonic analysis. However, the premise of FFT to accurately analyze the frequency spe...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R23/16
Inventor 唐轶刘昊秦媛倩李辉周斌陈雷杨洛尹远张跃渐伟
Owner CHINA UNIV OF MINING & TECH
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