Análise estocástica dos afundamentos de tensão em sistemas de distribuição.

Abstract

This document describes the procedure for estimating the probabilistic frequency of interruption of a sensitive load due to voltage sags in an electrical power distribution system. The procedure requires the construction of the voltage sag density table giving the probabilistic frequencies of voltage sags of certain ranges of sag magnitudes and durations. It has been shown that the voltage sag density table may be used to pinpoint the lines that are responsible for unacceptable voltage sags at the sensitive load bus. Maintenance of the critical lines, combined with proper coordination of the protective relays leads to significant reduction in the rate of tripping of the sensitive load. Finally, it has been shown that voltage sag-density tables generated at a few bus bars, together with voltage sag magnitude and duration measurements at these nodes, permits the location of the faults in the distribution system.