Commitment of Fast-Responding Storage Devices to Mimic Inertia for the Enhancement of Primary Frequency Response

One distinctive feature of renewable energy resources is that they contribute little inertia to power systems. With less system inertia, power grid is less capable of resisting frequency deviation from its nominal value in the first few seconds after disturbances. However, fast-responding storage devices can mimic inertial responses through some specified control algorithm. Thus, this paper focuses on the economic aspect of resource inertia as a service to the grid operation and aims to find a minimum-cost commitment of fast-acting storage devices for the enhancement of primary frequency responses. Costs are assigned to those storage resources and a commitment cost minimization problem is formulated with nonlinear primary frequency response constraints. A tractable iterative solution approach is developed and a sensitivity-based method through a rapidly solvable linear approximation of the nonlinear constraints is proposed to reduce the computational burdens of solving the optimization problem for large-scale systems. The effectiveness of the proposed methods is demonstrated using simulation results obtained using the 118-bus IEEE reliability test system.