Multi-Functional Siting and Sizing of Grid-Forming Battery Energy Storage for Energy Balancing and Grid Support

Abstract

High renewable penetration requires energy-storage planning to coordinate chronological energy balancing, frequency security and locational voltage support. This paper develops a joint siting and sizing model for grid-forming battery energy-storage systems with independent battery-power, battery-energy and power-conversion-system ratings. Virtual inertia, fast and primary frequency response, emergency reserve and steady-state reactive support are coupled to operating headroom and stored energy. Instantaneous activation envelopes and cumulative exposure distinguish peak hardware occupancy from service duration. Representative-day unit commitment, discrete converter options and fixed affine AC constraints yield a mixed-integer second-order cone program, followed by nonlinear AC verification and reference updating. Simulations on a modified IEEE 39-bus system produce a coordinated allocation of 810 MW, 3180 MWh and 850 MVA that satisfies the stated network and aggregate frequency-security criteria for the tested states. Relative to simultaneous stacking, the reported allocation reduces battery power, energy and converter capacity by 3.57%, 3.64% and 5.56%, respectively. A nested-feasible-set argument and comparable solver bounds support the fixed-reference cost comparison. Sensitivity studies quantify the effects of controller settings, service duration, overlap and disturbance requirements. These results demonstrate the value of coordinating hardware ratings while retaining explicit limits on service sharing and model applicability.