Harmonic energy metering method of Nuttall self-convolution weighted Fourier transform

A technology of Fourier transform and electric energy measurement, which is applied in the field of signal processing and can solve problems such as spectrum leakage and mutual interference between harmonics

Inactive Publication Date: 2012-05-02
ELECTRIC POWER RES INST OF GUANGXI POWER GRID CO LTD +1
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Problems solved by technology

[0005] The purpose of the present invention is to overcome the defects of the existing windowed Fourier transform harmonic energy measurement method, provide a simple Nuttall self-convolution window weighted Fourier transform harmonic energy measurement method, and solve the spectrum leakage in the signal weighting process If it is too large, the problem of mutual interference between harmonics, thereby improving the accuracy and practicability of signal harmonic analysis, and providing a reliable basis for further signal parameter identification and harmonic energy measurement

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  • Harmonic energy metering method of Nuttall self-convolution weighted Fourier transform
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  • Harmonic energy metering method of Nuttall self-convolution weighted Fourier transform

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[0056] specific implementation plan

[0057] The technical solutions of the present invention are further described below by way of examples.

[0058] Such as figure 1As shown, after the signal is sampled (discretized), the Nuttall self-convolution window operation is added to it, that is, the discretized signal is truncated with the Nuttall self-convolution window, and then the fast Fourier transform (FFT) is performed to obtain Discrete spectrum, search for its local spectral peak near the hth harmonic frequency, find the largest spectral line and the second largest spectral line of the local amplitude of the discrete spectrum, and determine the corresponding spectral line amplitude, and use the least squares interpolation algorithm for spectral interpolation Calculate, obtain the frequency offset, and obtain the harmonic parameters of each order, so as to output the harmonic electric energy value. The harmonic electric energy measurement method of Nuttall self-convolution...

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Abstract

The invention relates to a harmonic energy metering method of Nuttall self-convolution weighted Fourier transform. The method comprises the following steps that: a discrete Nuttall window sequence with a length of N is constructed; convolution operation is carried out on the discrete Nuttall window so as to obtain a convolution sequence; zero filling is carried out on the head or the tail of the convolution sequence so as to obtain a discrete Nuttall self-convolution window; the Nuttall self-convolution window sequence is utilized to carry out weighted operation on a discrete power signal; Fourier transform is employed to obtain a discrete frequency spectrum of the power signal; spectral lines with a greatest amplitude and a second great amplitude are searched nearby a harmonic frequency corresponded to the discrete frequency spectrum; fitting is carried out on a peak value spectral line by utilizing a least square method so as to obtain an amplitude, a frequency and an initial phase angle of a power harmonic wave, so that integral harmonic energy metering in a complex power signal is realized.

Description

technical field [0001] The invention relates to a method for measuring harmonic electric energy, in particular to a method for measuring electric harmonic electric energy by Nuttall self-convolution window weighted Fourier transform. It belongs to the field of signal processing. Background technique [0002] High-precision signal analysis and processing provide scientific basis for harmonic power flow calculation, equipment detection, power system harmonic compensation and suppression, vibration signal analysis and random fault processing, etc. When the Fourier transform theory is used for signal processing, due to the fluctuation or interference of the signal frequency, strict synchronous sampling cannot be realized, and the spectral leakage and fence effect will introduce large errors. [0003] According to the literature search, the use of window function to weight the signal can effectively reduce the spectrum leakage. The main lobe of the window function spectrum is di...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R23/16G06F17/14
Inventor 周毅波滕召胜卿柏元李刚温和高云鹏曾博唐求李伟坚陈桃王永朱少波蒋雯倩王勇
Owner ELECTRIC POWER RES INST OF GUANGXI POWER GRID CO LTD
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