Power quality indices estimation using robust estimation approach

This paper describes a new two-stage robust Newton-type numerical algorithm for power quality assessment in electric power systems. In order to estimate current and voltage spectra simultaneously with the fundamental frequency in the first algorithm stage, the robust Newton-type algorithm is applied. In the second algorithm stage, power quality indicators are calculated. Particularly the active, reactive, apparent and distortion powers are determined. As the main advantage, the technique provides estimates that are insensitive to frequency deviations and bad data, which often appear as a consequence of communication error, incomplete measurement, errors in mathematical models, etc. The algorithm performance is tested under laboratory conditions using the distorted voltage and current signals digitized during an AC-motor start. © Springer-Verlag 2004.