Qualitative and quantitative analysis of voltage sags in networks with significant penetration of embedded generation

This paper summarizes the findings of the research carried out in the area of the voltage sag (dip) propagation in distribution networks. The emphasis is on the influence of embedded generation on voltage sag characteristics and propagation. Two different, realistic, network topologies are used in the analysis. Different types of faults and different levels of embedded generation penetration are considered. The influence of embedded generation on symmetrical and asymmetrical voltage sags is assessed. Variations in voltage sag magnitude, phase-angle jump and sag propagation through the network as a function of the level and type of embedded generation are illustrated. New indices for the assessment of voltage sag propagation are proposed. The results of the research have shown that the effects, either beneficial or detrimental, of the embedded generation on voltage sag propagation and characteristics are closely coupled with the level of their penetration into the network and the location of the generators. Copyright © 2005 John Wiley & Sons, Ltd.