Signal harmonic analysis method and system based on Hanning product window

A harmonic analysis and product window technology, which is applied in the field of power system harmonic spectrum analysis, can solve problems such as difficult to achieve high precision in power systems, and achieve the effects of high practicability, real-time performance and accuracy, and short time consumption

Inactive Publication Date: 2014-09-24
WUHAN UNIV
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Problems solved by technology

However, the side lobe characteristics of the above window functions cannot suppress the spectrum leakage very well. They will ...

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  • Signal harmonic analysis method and system based on Hanning product window
  • Signal harmonic analysis method and system based on Hanning product window
  • Signal harmonic analysis method and system based on Hanning product window

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Embodiment Construction

[0037] The invention realizes the harmonic detection of power system signal based on the Hanning product window, and the Hanning product window w hanning-m (n) Through several Hanning windows w hamming (n) multiplied to obtain:

[0038]

[0039] In formula (1), p is the number of Hanning windows to be multiplied. In the specific implementation, the p value is selected according to the actual situation and experience. Generally speaking, the larger the p value, the wider the main lobe of the Hanning product window, the lower the peak height of the side lobe, and the faster the attenuation speed of the side lobe. A suitable window function requires a narrow main lobe, low side lobes, and fast attenuation of side lobes.

[0040] In this specific implementation, the following Hanning window w is used hamming (n):

[0041] w hanning ( n ) = 0.5 × ...

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Abstract

The invention discloses a signal harmonic spectral analysis method and system based on a Hanning product window. The method includes the steps that discrete signals are windowed through the Hanning product window, and FFT is conducted on the windowed signals and the Hanning product window; actual fundamental frequency and the amplitude and the phases of sub-harmonics are acquired according to a signal spectrogram obtained after FFT and the Hanning product window obtained after FFT. The Hanning product window is combined with FFT, and harmonic analysis with extremely high accuracy can be achieved in an asynchronous sampling state; meanwhile, the signal harmonic analysis method and system further have the advantages of being small in calculated amount, short in consumed time, high in practicability and the like.

Description

technical field [0001] The invention relates to a method for analyzing harmonic spectrum of a power system, in particular to a method and system for analyzing signal harmonics based on a Hanning product window. Background technique [0002] In the power system, the detection and processing of harmonics is very important to the power system. Accurate calculation of harmonics plays a vital role in the location of harmonic sources, harmonic control and maintenance of power system stability. However, the accuracy of harmonic calculation will be affected by environmental changes, especially when the frequency fluctuates and there is noise, the accuracy will be significantly reduced. At present, power systems widely use the frequency 4kHz or 10kHz specified by IEC61044 to sample signals, and then use fast Fourier transform (FFT) to process the sampled discrete signals. The asynchronous sampling caused by the fluctuation of the fundamental frequency will lead to spectrum leakage a...

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Application Information

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IPC IPC(8): G01R31/00G01R23/16G06F19/00
Inventor 武婕刘开培乐健汪立彭宏亮陈宜皇高云鹏
Owner WUHAN UNIV
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