METHOD AND SYSTEM FOR DETERMINING A SYNCHRONOUS MACHINE FAULT CONDITION

The present disclosure relates to a method of determining an electromechanical fault condition in a synchronous machine having a stator a rotor, and an exciter, wherein the exciter is a rotating exciter having an exciter stator, an exciter rotor, and exciter stator windings, wherein the rotating exciter has an AC/AC type of stator-rotor arrangement, wherein the method comprises: a) obtaining an exciter current signal which is a measurement of an exciter current flowing through the exciter stator windings of the exciter, wherein the exciter current signal is an exciter stator current, b) transforming the exciter current signal to obtain an exciter current frequency spectrum, and c) determining that a stator short-circuit fault is present in case the harmonic content of the exciter current frequency spectrum comprises a dominant frequency component at 3f s *(1-2s), where f s is the power supply frequency and s is the rotor slip of the exciter..