Optimal Scheduling of Flexible Ramp Capacity of Power Systems with Battery Energy Storage

With the increasing penetration of wind power in recent years, its fluctuation and uncertainty pose a greater challenge to the power system. More ramping capacities are needed to cope with the wind ramp events. Due to its fast charging and discharging and bi-direction power flow, energy storage has good ramp performance that can be used to provide flexible ramp capacity to improve the flexibility of operation. Recent studies on ramp capacity mainly focus on real-time scheduling but neglect the multi-scale nature of wind ramp events. In order to meet real-time scheduling, it is necessary to prepare sufficient reserves in advance. Based on this, this paper embeds flexible ramp capacity into day-ahead scheduling. The energy storage considering its flexible ramp capacity is modeled. The control strategy in different time scales is discussed. The state of charge (SOC) management is taken into account. An optimal unit commitment model considering the flexible ramp capacity of energy storage is proposed. The effectiveness of the proposed model is verified on IEEE RTS 24 bus system using Python 3.6.