Estimativa da frequência de desligamento de uma carga sensível provocada por afundamentos de tensão.

Abstract

In this work a method has been described to estimate the probabilistic frequency of interruption of a sensitive load because of voltage sags in an electrical power system. The input data for this method are system impedances, system topology, characteristics of protective devices and records of fault events in the utility’s system. With these data, the probabilistic short-circuit study of the system has been carried out and the possible voltage sags that can occur at the terminals of the sensitive load have been determined. With the information of the magnitude and duration of these sags, a table of probabilistic quantities occurrences of the sags has been constructed. Using the records of fault events in the utility’s system and a table of probabilistic quantities, another table of probabilistic occurrences frequencies is constructed. Finally, by comparing the table of probabilistic frequencies of sags with acceptability curve, the frequency of interruption of the sensitive load due to voltage sags has been estimated. With input date of real electric system, simulation results have been presented, analyzed and compared with field measurement. Keywords: Stochastic prediction