Assessment of air-gap flux variation to short-circuit current of generator excitation windings

This paper presents a fault monitoring method of a synchronous generator that exploits the variation and sensitivity of the air-gap flux for short-circuit operation modes. The electromagnetic transient analyses of the generator under the various short-circuit conditions in field windings are performed by an EM software package. The effect of the fault currents on the air-gap flux variation is investigated in terms of the Signal to Noise ratio and the Percentage Contribution of Taguch´s design of experiment method on the basis of a healthy operation mode. Finally it is revealed that the proposed method can be a powerful strategy for monitoring and diagnosis of the field windings of large-scaled synchronous generators.