Simulation-based FFR Requirement Identification Approach for Battery Energy Storage System

Fast frequency response (FFR) is considered to be a new very fast service provided by utility-scale battery energy storage systems (BESS) to complement the support typically delivered by synchronous generators (e.g., the governor response). The successful implementation of FFR depends on the power reserve allocation, which is a certain amount of power reserve available on standby to respond to sudden generation mismatches. Grid operators identified that the time delays and ramp rates of BESS are key impact factors for the determination of the FFR requirement. Still, current methods do not include a wide range of BESS time-response characteristics. This paper develops a simulation-based method that determines the FFR power reserve needed for BESS considering Delaunay triangulation. Results obtained using two renewable penetration cases demonstrate that the power reserved for FFR is sufficient to avoid under-frequency load shedding (UFLS) activation. This provides relevant insights into the reliable power-reserve allocation of BESS for planning.