Frequency response analysis of the stabilizing effect of a synchronous machine damper

The paper describes the application of frequency-response concepts to the analysis of a synchronous machine damper in so far as it affects the stability of the machine. The analysis of damper effects is based on Park´s equations. Small-displacement theory is introduced toorganize the equations into the correct form for frequency-response computation. Nyquist diagrams are used to show the stabilizing effect of a damper and to illustrate the method of optimizing damper parameters.