Simulation of Transient State Impacts from Low Power DG Aiming at Improving Power Quality and Reliability of Distribution Networks

Presence of independent and self producers in the electric system can represent significant impact on the operational characteristics of distribution networks. Many of these sources, even at low power, may cause significant impacts on the transient state because of switching operations. The main problem is that these effects are not well known yet. New sources connected at the grid will alter the short circuit levels, and may cause bad operation of the protective devices. Thus, it is important to determine precisely these effects originated in the Distributed Generation (DG). In this way, the electric energy companies, independent or self producers, can decide for a standard protection system, to minimize the impacts. The considerations and results described in this paper are integrant parts of the Research & Development Program developed for the State Company of Electric Energy (CEEE) and the Federal University of Santa Maria (UFSM).