New Digital Algorithms for On-line Determination of Symmetrical Components in Power Systems

Using the Fourier method the Kalman theory and the Walsh functions, non-recursive algorithms for the on-line determination of the basic waveforms of the symmetrical components in three-phase power systems are introduced, investigated and compared. The circular rotating phasors of the symmetrical components are calculated from the orthogonal components instead of the three original signals. The numerical operations required for the on-line calculation can be reduced by one third. The developed algorithms combine the suppression of higher frequencies and the separation of the symmetrical positive- and negative-sequence components