Distributed generation impact on voltage sags in distribution networks

Characteristics of voltage sags caused by faults in distribution networks depend on the design of the protection system and the coordination between the different protective devices. The presence of distributed generation (DG) changes the radial nature of distribution systems, so it can affect the performance of the protection system, and consequently the characteristics of voltage sags. In addition, DG will help to maintain the during-fault voltages of healthy phases. This paper explores the impact that DG can have on voltage sags characteristics by means of a small test distribution network and presents a simple method to compare and rank the performance of protection systems.