Frequency Stability Enhancement of a Large-Scale PV Integrated Grid

Renewable Energy System (RES) integration in existing grids to lessen adverse effects of fossil fuel based generations is advancing in recent years. Regarded as one of the most exciting prospects among RESs, Solar Photovoltaic (PV) system is being used as an alternative to conventional synchronous generators in many countries. Naturally having no inertia and governor settings, PV system does not provide frequency support like synchronous generators. Rather, it increases frequency instability in large-scale PV integrated grids following contingency event. To enhance frequency stability, additional mechanisms are mandatory to provide instant support following grid disturbance. Regarding this issue, this paper investigates the effect of adding properly modeled Battery Energy Storage System (BESS) on frequency stability of a large-scale PV integrated grid after a generator contingency in different PV penetration scenarios. In addition, synchronous condensers (SCs) are also installed to explore combined effects of these mechanisms on frequency stability. These simulations are conducted using IEEE 39 Bus New England test system in DIgSILENT PowerFactory environment. The results show additional support mechanisms can enhance frequency stability substantially under different scenarios of PV penetration levels.