Improved Cycle Control and Sizing Scheme for Wind Energy Storage System Based on Multiobjective Optimization

Abstract

This paper proposes an improved control and sizing scheme for a wind energy storage system for wind smoothing. Considering the trading rules in the electricity market, a cycle control strategy with progressive cycle period including one charge and discharge period is proposed. To determine the reference output and time duration of each cycle control period, a multiobjective optimization model is presented considering both the maximum of time duration of each cycle control period and the minimum of power variation between adjacent charge and discharge intervals. In the proposed control strategy, wind power is smoothed with flexible reference output and self-adjustable battery state of charge ranges, and then, the battery can be utilized without overdischarge. Meanwhile, the smoothed wind power with longer average interval duration can better benefit the wind power trading in electricity market. Besides, the charge/discharge switch can be significantly decreased to prolong the battery lifetime. Afterward, based on the presented control strategy, the sizing methodology is proposed according to the cumulative probability function of the charge/discharge power and energy. Moreover, the impact of wind power forecast error is also considered in the real-time operation. By using actual wind power data, case studies are fulfilled to validate the performance of the proposed cycle control and sizing strategy.