Extraction of symmetrical components in the presence of harmonics

A new microprocessor-based symmetrical component analyser, readily useful for power system application under non-sinusoidal conditions, is described. Use of simple look-up table saves time otherwise required for software multiplication. The instrument stabilises within one cycle of the wave and provides as output the sequence components of the fundamental. Experimental results demonstrating the utility of the instrument are presented on a model system with fifth-harmonic being allowed in the unbalanced 3-phase currents. © 1986, Sage Publications. All rights reserved.