Harmonic analysis method of power system using hht

Abstract

The invention discloses a method for analyzing harmonics of a power system by adopting Hilbert-Huang transform (HHT), and belongs to the technical field of power quality analysis of power systems. According to the technical scheme, the capable of obtaining integral mode function components of an original signal by adopting HHT comprises the following steps of: obtaining each mode function component of the original signal of a power signal by adopting HHT, judging whether mode mixing exists or not, separating the mode-mixed part of the original signal of the power signal from the original signal, sequentially performing Fourier transform and filtration on an analysis signal, performing HHT on the filtered signal to obtain each mode function component of the analysis signal, and integrating mode function components without mode mixing and each mode function component of the analysis signal to obtain the integral mode function components of the original signal. The method is applied to an electric power sector.

Description

technical field [0001] The invention adopts a power system harmonic analysis method of HHT, and belongs to the technical field of power system power quality analysis. Background technique [0002] In 1998, Huang et al proposed a new time series signal analysis method - HHT (Hilbert-HuangTransform), which is a major breakthrough in the analysis of linear and steady-state spectra based on Fourier transform. Analytical methods for nonlinear nonstationary signals. [0003] HHT consists of two processes: first, the signal is decomposed into a limited number of intrinsic mode function (intrinsic mode function, IMF) components through empirical mode decomposition (empiricalmodedecomposition, EMD), and then the IMF is subjected to Hilbert transformation to obtain the instantaneous frequency and instantaneous amplitude; EMD It is the core process of HHT, because only the Hilbert transformation is performed on the IMF after EMD, and the obtained instantaneous frequency and instantane...

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Problems solved by technology

[0004] EMD has the problem of modal aliasing in practical applications. When the frequency of the two component components in the signal is within 2 times the frequency, EMD cannot decompose it; DEERINGR and KAISERJF published "Theuseofamaskingsignaltoimproveempiricalmodedecomposition" proposed The masking signal EMD method, but the selection of two parameters to construct the masking signal is difficult, which affects the further promotion of the method; SENROYN and SURYANARAYANANS proposed the frequency heterodyne EMD method in "Two techniques to enhance empirical mode decomposition for power quality applications", but due to the error of EMD decomposition and Boundary effects will produce pseudo-modal components in the low frequency band, and these pseudo-modal components will be reversed into high-frequency components after frequency heterodyning, which are mixed with real high-frequency components and are difficult to distinguish; therefore, on the basis of existing methods, Reasonable use of HHT to accurately analyze the harmonics of the power system is a hot and difficult point in current research

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