Harmonic rapid analysis method and system based on windowing four-spectral-line interpolation FFT

A fast analysis, quadruple line technology, applied in the field of harmonic analysis, can solve the problems such as the inability to meet the requirements of high-precision harmonic analysis, the slow calculation speed, and the increase in the calculation amount of the modulo

Active Publication Date: 2015-09-09
SOUTH CENTRAL UNIVERSITY FOR NATIONALITIES
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Problems solved by technology

[0007] However, in practical engineering applications, bispectral and trispectral interpolation algorithms still cannot meet the requirements of high-precision harmonic analysis, and as the number of spectral lines used increases, the amount of calculation for modulus also increases rapidly, resulting in the calculation speed slower

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  • Harmonic rapid analysis method and system based on windowing four-spectral-line interpolation FFT

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Embodiment Construction

[0144] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0145] see figure 1 As shown, the embodiment of the present invention provides a fast harmonic analysis method based on windowed four-spectrum interpolation FFT, comprising the following steps:

[0146] S1. Signal preprocessing:

[0147] The transformer collects the grid signal, the grid signal includes the current signal and the voltage signal, and transmits the discrete grid signal x(n) collected by the transformer to the host computer, where n is the ordinal number of the sampling point, and n is a natural number; the discrete cosine window function is used w(n), perform windowing and truncation on the power grid signal x(n), and obtain the windowed signal x w (n):

[0148] x w (n)=x(n)w(n) (1)

[0149] The expression of the discrete cosine window function w(n) is:

[0150] w ( n ...

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Abstract

The invention discloses a harmonic rapid analysis method and system based on windowing four-spectral-line interpolation FFT, and relates to the field of harmonic analysis. The method comprises the following steps: signal preprocessing; the determining of four spectral lines; the calculation of a modifier formula of a four-spectral-line interpolation algorithm; the calculation of a fundamental wave parameter; the performing of a four-spectral-line interpolation rapid algorithm; the determining of a harmonic parameter; and error analysis. The method starts with a frequency domain expression of a windowed power grid signal of a power system, and a phase rule among the four biggest spectral lines adjacent a real spectral line point after windowing FFT is deduced according to the rule of a phase different pi between any two adjacent spectral lines in a main lobe of a window function. The invention proposes a windowing four-spectral-line interpolation FFT rapid algorithm. Compared with two-spectral-line and three-spectral-line interpolation algorithms, the method provided by the invention effectively improves the precision of harmonic analysis. The method just needs one modular operation for a harmonic wave at a certain order, can effectively reduce the calculation amount and time, and remarkably increases the calculation speed.

Description

technical field [0001] The invention relates to the field of harmonic analysis, in particular to a fast harmonic analysis method and system based on windowed four-spectrum interpolation FFT. Background technique [0002] With the use of a large number of nonlinear power electronic devices, the problem of harmonic pollution in the power grid is becoming more and more serious. Harmonic problems not only deteriorate the power quality, but also have a great impact on the safety, stability and economic operation of the power grid. Therefore, it is very necessary to measure the harmonic parameters in the system with high precision to reduce the harm of harmonics and maintain the safe, stable and efficient operation of the power grid. [0003] FFT (Fast Fourier Transform, Fast Fourier Transform) is currently the most commonly used algorithm for harmonic analysis of power systems, but it is difficult to achieve synchronous sampling and full-period truncation by using FFT to analyze...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R23/16
Inventor 张俊敏刘开培汪立王黎田微何顺帆姚为
Owner SOUTH CENTRAL UNIVERSITY FOR NATIONALITIES
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