Damper windings phenomena of synchronous machines during system oscillations

The performances of the damper windings of a synchronous machine (generator) under the oscillatory conditions of the power system to which it is connected, are investigated both experimentally and analytically in this paper. Air-gap fluxes and induced voltages and currents of the damper windings under the oscillatory system conditions, when the machine is equipped both with and without damper windings, are measured and analyzed. Fourier analyses are used to examine the harmonic components appearing in the air-gap flux density distributions and the damper induced voltages and currents to clarify the phenomena caused by the damper as well as the effect of the damper upon power system performances