Dispersed Generation Systems Impact on the Voltage Sags in Distribution Systems

This paper presents the influence of dispersed generation systems (DGS) on the voltage sags in distribution systems. One radial and one closed-loop distribution feeders of Taipower system are selected for study. The DGS with the synchronous and induction generators are assumed to be installed at different sites of the feeders to find the impact on the voltage sags. By integrating the ITIC curve and the SEMI F47 curve into a wider range of ride-through capability curve, and another CBEMA curve have both been adopted in this paper to evaluate the effect of voltage sags. Also, number of voltage sags occurred per year is predicted and presented by performance contour charts for the radial and closed-loop feeders with and without considering the installation of DGS. It is found that the close-loop feeder can resist the voltage sags better than the radial feeder. Besides, the voltage sags can be improved by the installation of DGS, synchronous generator type especially. However, most of the sag events are still sited below the suggestion equipment ride-through capability curves.