Analytical approach to probabilistic prediction of voltage sags on transmission networks

Quantification of voltage sags at a location of interest is the basic requirement for assessing the compatibility between equipment and electrical supply. An analytical method is described that has been developed to determine the probability density functions of voltage sags caused by three phase faults across the network. The method takes into account the impact of fault positions along transmission circuits and patterns of generation associated with the corresponding load demands on the voltage sag profiles. The developed algorithm is applied to the IEEE 24-bus reliability test system to verify the technique and illustrate its application.