Hierarchical Regulation Strategy for Smoothing Tie-Line Power Fluctuations in Grid-Connected Microgrids With Battery Storage Aggregators

The high penetration of renewable energy in grid-connected microgrids creates the tie-line power fluctuations, which can increase operating costs and even pose security and stability risks. Yet, we continue to lack efficient tools to smooth the tie-line power fluctuations within the context of microgrids. In this article, a hierarchical regulation strategy is proposed for smoothing the fluctuations of tie-line power flow in grid-connected microgrids equipped with battery storage units (BSUs), where the BSUs are aggregated into several battery storage aggregators (BSAs) to facilitate the management. This strategy comprises two layers: an upper layer employs a multiple-horizon predictive optimization-based approach to compute the required power allocation for each BSA, ensuring smoothed power trajectories while adhering to system constraints. Subsequently, a lower layer employs a distributed fast tracking-based technique to distribute the allocated power among BSUs within each BSA using predefined-time control theory. Case studies validate the effectiveness of our approach.