Two-level Day-ahead Optimal Scheduling of Distributed Energy Storage System

Stochastic characteristics of wind and photovoltaic (PV) power causes great challenge for power system operations. Distributed energy storage system (DESS) can mediate the intermittent renewable energy. This paper proposes a two-level optimization method for DESS scheduling. Firstly, DESSs are aggregated in a virtual power plan (VPP) and participates the power scheduling as a whole, the power schedules of DESSs are obtained with the proposed two-level optimization method. Secondly, in the upper-level optimization model, a two-stage stochastic unit commitment model is established with considering power uncertainties, and thermal units as well as VPP of DESS are optimized to maximize the power generation of renewable energy. And then, in the lower-level optimization model, an optimization model is proposed to schedule each DESS in order to minimize the total life loss cost of DESSs. Case studies are inducted based on actual data of a provincial power grid. The effectiveness and practicability of the proposed method is verified by the testing results.