A new harmonic measurement method based on VMD and STEKF

摘要

With the extensive application of power electronic devices and non-linear loads, harmonic inevitably exists in power system. This paper proposes a new method for global harmonics measurement including integer harmonic and inter-harmonic under both stationary condition and dynamic condition. The new proposed method consists in applying the Variational Mode Decomposition (VMD) for harmonic extraction, then using Strong Tracking Extended Kalman Filter (STEKF) to calculate the instantaneous amplitude and frequency of harmonic. An adaptive algorithm for finding appropriate parameter K of VMD is used to ensure that there is no false mode in the VMD result. The performance of proposed method is compared with Fast Fourier Transform (FFT) based methods, Wavelet Transform (WT) based method and Hilbert-Huang Transform (HHT) based method in different harmonic conditions. The result of simulation argues that the new proposed method is suitable for global harmonic measurement which contains inter-harmonic and dynamic harmonic.