Frequency Dynamics Constrained Unit Commitment With Battery Energy Storage

The decline of system inertia due to the increasing displacement of synchronous units by renewable units has introduced a major challenge on the frequency dynamics management of a power system. This paper discusses how fast-response battery energy storages can be used to maintain the frequency dynamic security. Immediately following a generation loss, the injections of batteries are adjusted instantly to ensure minimum power imbalance in the system. This control strategy is included in a novel formulation of the frequency dynamics constrained unit commitment, in which the impact of wind uncertainty is dealt with using interval-based optimization. The reformulation-linearization technique is applied to reformulate the original nonlinear model as a mixed-integer linear programming problem. Case studies on a six-bus system and the modified RTS-79 system demonstrate that the proposed method guarantees frequency security while still preserving economy without curtailing wind generation.