Accurate method to measure harmonics and interharmonics in shipboard power quality analysis

Abstract

This thesis describes a novel approach that utilizes a special property of the Hanning window to accurately detect the fundamental frequency of the data signal in the presence of harmonic and interharmonic interference. After obtaining the fundamental frequency, the same procedure is applied to all possible harmonics to be filtered for further analysis of the interharmonics. The proposed approach is validated using numerical tests. In the literature, different authors have shown the difficulty of extracting a synchronized sampling frequency from the analyzed signal and discussed the effect of deviation of the fundamental in the presence of harmonics. This thesis suggests a new approach to overcome the difficulties, even if the interharmonics present are in frequency bins near the fundamental.In order to perform the interharmonic analysis, the author followed the IEC standard draft signal processing recommendations, with the exception of using a

A review of measurement and analysis of electric power quality on shipboard power system networks

“…A comparison of different methods for harmonic estimation in shipboard power networks using Fourier analysis with different sampling windows, synchronization and different interpolation methods is presented in [57]. A special property of the Hanning window is applied in [58] to accurately detect the fundamental frequency of a signal in the presence of harmonic and interharmonic distortion. After obtaining the fundamental frequency, the paper applies the same procedure to all possible harmonics to be filtered for further analysis of interharmonics.…”

A Computationally Efficient RDFT Based Reference Signal Generator for Active Compensators

“…The expression (13) has to be executed at each sampling cycle and the updated value of Nc then will be used in expressions (14) and (15). In order to summarize the above discussions, the following procedure is suggested for the RDFT computations in active compensator applications.…”