A simulated model of the synchronous generator connected via the transsmision lines and transformer to the power grid in PLECS is developed. A mathematical d-q model of synchronous generator was modeled and the saturation was included in d axis. All parameters except time constants are defined in per unit which are obtained by division the actual value with the base one, while the time constants are expressed in seconds. In the first part of the analysis behaviour of the synchronous generator at constant torque input was observed, and in the second part behaviour at torque made by primary mover (a turbine) was analyzed. In both cases behaviour in inductive and capacitive area is observed with included excitation regulation by entering the reference value of reactive power . Regulation of the excitation system is realised via converter, P current controller, PI voltage controller, reactive power compensator and PI reactive power controller. A simulation model of turbine and its regulation is developed, whereby in trubine regulation subsystem active power and speed of synchronous generator are regulated.