The paper deals with a synchronous generator from an energetic group with distorting and unbalanced behavior during its steady state operation. Waveforms from main and auxiliary generators and from the main generator excitation winding were analyzed. Harmonics determinations and powers calculations were done. For a low harmonic level in the main generator stator, conclusions on the generator steady state operation can be made. Even harmonics could be caused either by an asynchronous thyristors control or by the auxiliary generator unbalanced operation.

Keywords: Distorting and unbalanced regimes, Synchronous generator, Diagnosis.