Enhancing grid stability and resilience through BESS optimal placement and sizing in VRES-dominated systems

The rapid global shift toward renewable energy, propelled by international commitments such as those made at the 28th session of the Conference of the Parties to the United Nations Framework Convention on Climate Change (COP28), has underscored the critical need to address grid stability challenges posed by the widespread integration of Variable Renewable Energy Sources (VRES). Reducing system inertia, characteristic of VRES-dominated grids poses significant risks to frequency stability. This research investigates the optimal placement and sizing of Battery Energy Storage Systems (BESS) to mitigate these challenges using a methodology that combines active power frequency sensitivity analysis with reactive power (Q) limit evaluation. By identifying the optimal bus for BESS installation, the approach ensures a balance between maximizing frequency sensitivity and minimizing reactive power absorption, thereby maintaining voltage stability within prescribed grid code limits. Tested on the IEEE 14-bus system using PSS/E software, the methodology demonstrates substantial improvements in key frequency stability metrics, including enhancement in frequency nadir, a stable settling frequency, and a reduced Rate of Change of Frequency (RoCoF). Additionally, a reduced battery energy capacity underscores the method's cost efficiency. The study reveals that strategic deployment can significantly enhance grid resilience in VRES-dominated environments, providing a scalable and economically viable framework to support the global transition to renewable energy.