Impact and management of power system voltage sags

This chapter examines the causes and impacts of voltage sags. A definition for voltage sags is provided as well as a summary of the causes of voltage sags. Data collected from field measurements is then provided in order to give the reader an understanding of the actual (empirical) behaviour of voltage sags in the field. The chapter then provides an example of how to calculate the impact of voltage sags. This is followed by an evaluation of the impact of voltage sags in terms of equipment performance, industry immunity curves, network capability and finally economic impact. Mitigation options from both a network and equipment/installation perspective are then detailed. The chapter concludes by providing insight into methods of assessing and reporting voltage sags.