Method for quickly calculating power harmonic parameters in high-accuracy mode

A fast calculation and power harmonic technology, applied in spectrum analysis/Fourier analysis, etc., can solve the problem of increasing the calculation amount of harmonic estimation accuracy

Inactive Publication Date: 2012-12-12
CHINA UNIV OF MINING & TECH +1
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Problems solved by technology

[0004] The purpose of the present invention is to provide a method for quickly calculating electric harmonic parameters with high precision, which solves the problem in the prior art that the accuracy of harmonic estimat

Method used

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  • Method for quickly calculating power harmonic parameters in high-accuracy mode
  • Method for quickly calculating power harmonic parameters in high-accuracy mode
  • Method for quickly calculating power harmonic parameters in high-accuracy mode

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Embodiment 1

[0031] Example 1: Utilize the property that the digital signal "shrinks" in the time domain and "stretches" in the frequency domain after Fourier transform, and accurately calculates the frequency of the power harmonic through the 2nd FFT, and then through the symmetrical window function in the frequency domain The method of interpolation calculates the amplitude and phase of each harmonic of the power;

[0032] Take the following steps to make it happen:

[0033] Step a. Take the sampling period as Sampling the power signal to be analyzed, that is, voltage or current signal: , according to the measurement accuracy requirements, select the symmetric window function Truncating the sampled power signal gives: , N truncates the length of the data for the window function, and truncates the signal Perform a fast Fourier transform to get:

[0034] , ;

[0035] The symmetric window function described is Hanning, Hamming, Black or Nuttall window function;

[003...

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Abstract

The invention provides a method for quickly calculating power harmonic parameters in a high-accuracy mode and belongs to analysis and automatic monitoring algorithm of power grid voltage and current waveform distortion. Firstly, a symmetrical window function is used for cutting off a sampled power harmonic signal and performing fast Fourier transform (FFT) to the cut signal, and then the same window function is used for cutting off sample data with the half length from the same starting point and performing the FFT. A fundamental wave and frequency of sub-harmonic waves are calculated accurately according to the fact that phase difference angles of twice FFT are zero, then a method for interpolating in a symmetrical window function frequency domain is used for calculating correction coefficients of the fundamental wave and the sub-harmonic waves, and finally amplitude values and phase positions of the sub power harmonic waves are calculated. The method for quickly calculating the power harmonic parameters in the high-accuracy mode has more obvious superiority than other windowing FFT interpolation correction analyzing methods in consumed calculation time, greatly decreases the calculated amount, is best for a digital signal processor (DSP) provided with FFT hardware and has practical value.

Description

technical field [0001] The invention relates to an analysis and automatic monitoring algorithm of grid voltage and current waveform distortion, in particular to a method for quickly calculating power harmonic parameters with high precision. 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 is the fastest tool for harmonic analysis, and the English abbreviation of Fast Fourier Transform is FFT. However, the premise of FFT to accurately analyze the frequency spectrum is to ensure the synchronous sampling and truncation of the entire pe...

Claims

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Application Information

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IPC IPC(8): G01R23/16
Inventor 唐轶刘昊谷露李建华孙瑜欣于正华于琪王飞黄巧娜王猛
Owner CHINA UNIV OF MINING & TECH
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