Comparison among techniques for distorted waveforms analysis in power system

Measurement and analysis experiences have shown great difficulties in interharmonic detection and measurement due to their small amplitudes and their consequent vulnerability from harmonics spectral leakage. The spectral leakage is due to lack of synchronization between the analyzed waveforms actual periods and the sampled window length, deriving from both fundamental frequency deviations and nonsynchronized interharmonics. This paper compares the techniques, that are introduced by the same authors in previous papers and that improve the IEC recommended signal processing: the utilization of the classical Hanning Window, in place of the Rectangular; the harmonic filtering and the self tuning signal processing. All the techniques are applied to numerical and experimental tests showing the different performances.