Metodologia para parametrização da função de subtensão utilizada em geradores distribuídos

Abstract

One of the main concerns when sizing protection systems in distribution networks with distributed generation connection is to ensure that islanding of these plants does not occur. For this, several protection techniques are used, among which is the use of an undervoltage relay. It happens that the voltage degradation caused by the occurrence of short circuits in feeders adjacent to the DG connection can sensitize this protection, causing undue actions. Thus, this work presents a methodology for custom parameterization of the undervoltage relay in order to reduce or avoid these actuations. The methodology checks for which situations the undue actuation occurs, evaluating the overcurrent protection actuation time and the voltage drop at the DG connection point. Starting from these data, a customized actuation curve for the undervoltage relay is established. This curve is based on steps in order to facilitate its application in undervoltage relays, where a maximum number of steps starting from two must be defined. For the scenarios tested through computer simulations, the methodology proved to be efficient, zeroing the number of undue actions for all scenarios except one.