Fast estimation of symmetrical components in real time

Methods for online calculation of the phasors of symmetrical components from the complex space-phasor in three phase power systems are presented. In this way the number of numerical operations can be cut by one third. The methods combine the suppression of higher frequencies and the separation of symmetrical components. Transfer functions obtained from the developed filter algorithms for the complex input and output signals are investigated and compared. The proposed approach with a variable sampling window enables a faster estimation of the desired components under transient conditions compared to the method using a constant sampling window.