A new time-varying harmonic decomposition structure based on recursive hanning window

Analysis of power quality phenomena under time-varying conditions has become an important subject as the complexity of the grid increases. As a consequence, several methods have been developed/applied also to study power quality parameters during transient conditions such as time-frequency methods. This paper proposes a new time-varying harmonic decomposition structure based on a Recursive Hanning Window (RHWDFT). The Hanning window has good features such as sidelobe of -31.5 dB and asymptotic sidelobe decay rate of -18 dB/octave. The decomposition structure is very attractive for harmonic decomposition in presence of interharmonics. Illustrative examples comparing the performance of the RHWDFT with a Sliding Window Recursive DFT (SWRDFT) of two cycles are presented.