부산대학교 도서관

Aiming at the shortcoming of harmonic detection in power systems, a method based on Variational Modal Decomposition (VMD) is presented in this paper. This method combines VMD with Fast Fourier Transform (FFT) so that VMD can adaptively find the modal decomposition number ‘K’. K intrinsic mode functions (IMF) can be obtained by adaptive VMD decomposition of harmonic signals and Teager energy operator (TEO) analysis can be performed. By calculating the three sample points of the signal via TEO, the instantaneous amplitude and instantaneous frequency of one sample point can be acquired, so as to realize the harmonic detection of the power grid signal. Through the simulation of transient signal, the results of adaptive VMD are tested. At the same time, TEO and Hilbert transform (HT) are used to calculate the IMF respectively. Through contrastive analysis of the caculation, the feasibility and accuracy of the method mentioned in the article can be verified.