Advanced voltage sag characterisation II: point on wave

Abstract

Two important but often neglected characteristics of voltage sags and short interruptions are: point on wave of sag/interruption initiation and point on wave of sag/interruption ending. A critical review of existing approaches is presented and an appropriate definition of point-on-wave values proposed. An identification of point-on-wave values in monitoring applications is discussed and problems related to identification/assessment of point-on-wave values highlighted. Examples of equipment sensitivity to these phenomena are analysed. The results related to identified ranges and relationships of point-on-wave values are reviewed, using examples of sags and interruptions recorded in power supply systems. Adequate procedure for testing single-phase and three-phase equipment to sags and interruptions are discussed with respect to point-on-wave values.