METHOD FOR CONTROLLING GENERATOR VOLTAGE

An electrical power system comprises at least one synchronous generator (101), a signal transducer (102) for producing an amplitude signal indicative of the amplitude of generator voltage, and a controller (103). The signal transducer and the controller are parts of a voltage control loop for controlling the excitation of the synchronous generator on the basis of the amplitude signal and the reference amplitude. The voltage control loop comprises a band-rejection filter (104) or another signal conditioning device for suppressing frequency components corresponding to torsional mode oscillations of a rotating system that comprises the rotor of the synchronous generator and a rotating part of an engine or another prime mover. Thus, an adverse phenomenon where the voltage control loop maintains or even amplifies the torsional mode oscillations can be avoided.