Improved Hilbert-Huang Transform And Its Application Of The Signal Process In Power System

With the rapid development of the electric power industry, the expansion of power grid and a large number of nonlinear power components being adopted, the signal processing problem of electric power system is getting more and more complicated. Traditional time-frequency analysis method has certain limitation in dealing with complex fault signal which cannot meet the need of the real-time analysis of great disturbance and fault of electricity signal in power system, therefore, a new efficient non-stationary signal processing method is badly needed.Traditional methods of signal analysis, including Fourier Transform, Short Time Fourier Transform, Wavelet Transform, Wigner-Ville Distribution and so on, essentially are the improved integral transform methods, which have the flaw of the global Fourier analysis, and the theoretical basis is still the Fourier analysis localization. Strictly, these improvements method cannot completely meet the non-stationary process analysis of nonlinear strict requirements. Hilbert - Huang Transform completely break through the lack of the traditional time-frequency analysis method which is the Fourier transform on the basis of overall insufficient. According to the characteristic of signal, it does not need to choose base function and no longer subject to the Heisenberg uncertainty principle. It obtains the very good gathered Time-Frequency domain at the same time, has multi-resolution analysis and high adaptability, and is sensitive to the signal change. So, it is suitable for nonlinear non-stationary signal processing.This thesis studies the basic concept, theory and improvement method of the Hilbert - Huang Transform and then studies the application of the power system in signal processing. Which Including: 1. Introducing the Hilbert - Huang Transform, especially tracking the latest development. 2. Comprehensive research and discussion of the basic concept and theory of Hilbert - Huang Transform and verify it with the simulation signal and actual human pulse signal respectively, and summarizing the characteristics of Hilbert - Huang Transform. 3. Researching all the key issues and improved methods of Hilbert - Huang Transform, including envelope fitting, endpoint effect, sifting law and mode mixing, etc., and analyze the improved Hilbert - Huang Transform to the human pulse signal which again has proved the correctness and effectiveness of Hilbert - Huang Transform and contributed to its improvement. 4. Researching the signal processing of power system with the Hilbert - Huang Transform, and verified with the power system transient mutagenesis data and earth fault data. The result shows that this method can well realize the analysis of electric power system signal processing and enjoy a promising future in its application.