Computing and Analysing PQ Indices for a Consumer with Various Sources of Harmonics and Non-symmetries

The paper presents a detailed analysis of certain operating regimes that appear for a consumer with various sources of harmonics and non-symmetries. The analyzed waveforms were acquired with a portable dedicated data acquisition system and transferred to a laptop for processing with Fast Fourier Transform (FFT) and Wavelet Packed Transform (WPT). Small differences (FFT vs WPT) were noticed between the computed values of the power quality indices, due to the non-sinusoidal and sometimes non-symmetric nature of the studied regimes and discrete nature of the processed data respectively. The FFT analysis revealed significant non-symmetrical regimes, as great weights for harmonic orders multiple of 3 were found in the three-phase currents waveforms. Reversed flow of active and reactive powers were noticed. A comparative study of the energies produced by current harmonics was made and discussed. A non-symmetry of the consumer as a whole was detected as well.