The Application of Hilbert-Huang Transform in Harmonic Analysis of Power System

Hilbert-Huang Transform(HHT) has been proved to be a good method for analyzing nonlinear and nonstationary signals.This paper introduces HHT into the harmonic measurement of power system.The fault signal is first lydecomposed into intrinsic mode function(IMF) by the EMD method.Then instantaneous frequency and instantaneous amplitude is obtained by Hilbert transform to compose Hilbert spectrum.Thus the transient caused by fault can be analyzed and further detected accurately through the instantaneous frequency and the timefrequency amplitude spectra analysis.Simulations show that the HHT based method is accurate at fault location and faultmessage abstraction, which enhance the reliability of fault detection.