Application of Fuzzy Logic in Protection Against Loss of Excitation in Synchronous Generators Connected to Transmission Lines with SVCs

Abstract

With the advancement of power electronics, SVCs (Static Var Compensator) devices have been used for reactive compensation to improve the voltage profile in Transmission Lines (LTs). However, the change in the network topology with the insertion of such devices alters the measured impedance, and consequently can affect the response of the protective relays that are based on the characteristic impedance, as well as the excitation loss function (ANSI 40) of synchronous generators. Therefore, this work presents an investigation of these effects on the protection against excitation loss, including an alternative based on a fuzzy classifier, which uses the derivative of the reactive power and armature current of the machine to improve the detection of the response of this protection in this context.