Analysis by numerical simulation regarding the stability of the synchronous generator operating in autonomous or grid connected regime

The paper presents the functioning stability problem of the synchronous machine in two cases: autonomous regime and parallel with grid of a certain voltage and frequency. Through numeric simulations, in dynamic regime, there is proved the fact that the synchronous generator (SG) is operating in a stable dynamic regime for any value of the load, in autonomous regime or connected to the grid (U, f). The dynamic load limit depends on the initial functioning point and on the value of rotor inertia moment. Through, three relevant study cases (small, medium and high value of the rotor inertial moment), there is proved, the fact that the autonomous SG, contrary to the case of the one grid connected, does not lose its synchronism for any value of the load stress.