Frequency Constrained Optimal Siting and Sizing of Energy Storage

Abstract

Frequency problem happens more frequently considering the current low-inertia system and the increasingly uncertain renewable energy sources. Energy storage is expected to provide the power with high ramping to reduce the power imbalance, and further, to maintain system frequency within an allowable range. In this paper, a framework for the planning of energy storage considering frequency constraints is proposed. The RoCoF and frequency nadir are constrained in this model, and reformulation linearization technique is utilized to relax the nonlinear constraints into linear constraints. Through this framework, optimal locations and the corresponding capacities of energy storage can be obtained. Case studies are conducted on a six-bus system and the RTS-76 system, and the results show that frequency requirements are satisfied for both centralized and distributed deployment of energy storage. In addition, also, the results show that deploying energy storage distributed is more economical and has less wind power curtailment.