A Harmonic and Interharmonic Separation Analysis Method

Abstract

The invention discloses a harmonic and inter-harmonic separation analysis method, and the method comprises the steps: carrying out the sampling of an original electric energy signal, and carrying out the dividing of different analysis window; carrying out the windowing calculation of the original electric energy signal in each analysis window, and obtaining a windowing signal; carrying out the time domain averaging of the windowing signal, and obtaining a quasi-harmonic signal; carrying out the discrete Fourier transform of the quasi-harmonic signal, and obtaining a harmonic parameter; subtracting the quasi-harmonic signal from the original electric energy signal in the analysis windows, and obtaining a quasi-inter-harmonic signal; sequentially carrying out the windowing calculation of the quasi-inter-harmonic signal, adding zero to the tail of the sequence and carrying out the discrete Fourier transform, and obtaining an encrypted spectrum signal; analyzing the encrypted spectrum signal, and obtaining an inter-harmonic parameter. The method can accurately separate the harmonic and inter-harmonic components in one electric energy quality signal in a time domain, thereby inhibiting the spectrum interference between two sides during the analysis of the signal in the frequency domain, and improving the detection analysis precision of the harmonic and inter-harmonic.

Description

technical field [0001] The invention belongs to the electric power industry, and in particular relates to a method for analyzing harmonic and inter-harmonic components in electric power signals, and obtaining parameters such as frequency, amplitude and phase of each harmonic and inter-harmonic components. Background technique [0002] Discrete Fourier Transform (DFT) is currently the most common method for analyzing harmonics and interharmonics in power quality monitoring devices. However, when the analyzed power quality signal contains not only harmonics, but also inter-harmonic components, even if the sampling is synchronous to the fundamental frequency (that is, the frequency used is an integer multiple of the fundamental frequency), the analyzed harmonics and inter-harmonic components Harmonic parameters still have large errors. The reason is that there will be mutual interference between the frequency spectrum between harmonics and inter-harmonics. When the content of ...

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Problems solved by technology

However, when the analyzed power quality signal contains not only harmonics, but also inter-harmonic components, even if the sampling is synchronous to the fundamental frequency (that is, the frequency used is an integer multiple of the fundamental frequency), the analyzed harmonics and inter-harmonic components Harmonic parameters still have large errors

The reason is that there will be mutual interference between the frequency spectrum between harmonics and inter-harmonics. When the content of a certain harmonic component is small, it is easy to be overwhelmed by the leakage component (false component) of the harmonic, so it cannot be detected, even if can be detected, the calculation error of its parameters will also be affected by the leakage of harmonics and become larger; similarly, inter-harmonics will leak at the harmonic frequency point, affecting the analysis accuracy of harmonics

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