Optimal scheduling of energy storage system in wind power integrated system based on bi-level programming

Wind power is uncertain and fluctuating. To address its impact on system, a jointed scheduling model of wind power/thermal generation/ energy storage system (ESS) is established in this paper, based on bi-level programming (BLP). Operations of different types of power sources are optimized in the upper-level, while unit commitment of thermal generation is optimized in the lower-level. These two layers work together to yield the best results. Chance constrained programming is applied to address uncertainties of wind power. And a method to utilize the ESS as part of system reserves is introduced to reduce the total reserves required from thermal generation. A control strategy is also applied to maintain state of charge (SOC) reasonable, avoiding SOC reaching the critical area too often because of the rising utilization of ESS. Finally, results of case studies indicate that BLP is effective in optimizing ESS operation in wind power integrated system.