  The absolute requirement to increase the amount of energy generation from
renewable sources e.g. predominantly asynchronously connected wind turbines and
photovoltaic installations, may in practice during transient events (where
frequency changes are examined) excite oscillatory response of the power output
of large grid connected synchronous-generators. The response of such generators
must be controlled either by varying the applied torque of a turbine or by
altering the electromagnetic torque in the airgap. Choosing the latter, the
adequacy of a voltage regulator, particularly that of the embedded Power System
Stabilizer (PSS) circuit, is investigated using the IEEE PSS1A model for the
automatic voltage regulator of a synchronous generator driven by a gas turbine.
The response is obtained via closed form analytic solutions for both small
(linear) and large (nonlinear) scale transient events in the energy grid
system. In tandem with the analytical study, the behavior simulated with a
computer model from MatLab-SimPowerSystems is reviewed.
