Performance evaluation of grid-forming battery energy storage systems for stability enhancement in solar PV plants

High-penetration solar photovoltaic (PV) systems pose challenges for grid stability and reliability due to low inertia and voltage support. Battery energy storage systems (BESS) with grid-forming (GFM) control can emulate synchronous generators and provide fast frequency and voltage support. This paper evaluates a 100 MW PV plant co-located with a 60 MWh BESS (35 MW power), corresponding to an approximate discharge duration of 1.7 h at full power, under a range of operating and contingency scenarios (normal operation, large PV power fluctuations, load steps, grid outages, and faults). Time-domain simulations evaluate the dynamic response of the BESS inverter in GFM modes under different grid strengths. The analysis assesses compliance with IEEE Std. 2800-2022 performance requirements (fault ride-through, reactive support, frequency response, etc.). In all cases, the grid-forming control provided immediate active/reactive support, mitigated voltage sags, and met IEEE-2800 fault-ride-through requirements. These results demonstrate that the proposed GFM BESS significantly enhances transient stability and ride-through performance in high-PV plants, especially under weak-grid conditions.