Advanced characterization of voltage sags and assessment of equipment sensitivity

The paper proposes a new approach for characterization and classification of voltage sags and for the assessment of sag influence on sensitive equipment. The existing classifications of voltage sags mainly use the method of symmetrical components and describe voltage sags in terms of magnitude and duration. It has been recognized though, that the other sag characteristic may influence sensitive equipment operation. In this paper, the approach based on Odq-components method (Park's transformation) is used for sag description and equipment sensitivity assessment. This approach enables to represent voltage sags as a function of time, magnitude, instant of fault initiation and phase-angle jump at the same time or as a function of more than two characteristics simultaneously. Furthermore, this new representation of voltage sags facilitates the investigation of equipment sensitivity to phase-angle jump, moment of fault initiation and to any combination of these and other sag characteristics.