Transient stability assessment of synchronous generator in power system with high-penetration photovoltaics

As photovoltaic (PV) capacity in power system increases, the capacity of synchronous generator needs to be reduced relatively. This leads to the lower system inertia and the higher generator reactance, and hence the generator transient stability may negatively be affected. In particular, the impact on the transient stability may become more serious when the considerable amounts of PV systems are disconnected simultaneously during voltage sag. In this work, the generator transient stability in the power system with significant PV penetration is assessed by a numerical simulation. In order to assess the impact from various angles, simulation parameters such as levels of PV penetration, variety of power sources (inverter or rotational machine), and existence of LVRT capability are considered. The simulation is performed by using PSCAD/EMTDC software.