Multi-timescale Coordinated Planning of BESS, Seasonal Hydrogen Storage, and Dynamic DR for Unbalanced RES-rich Microgrids

Nowadays, integrating renewable energy sources (RESs) poses significant challenges due to the deterioration of performance indices, especially in cold-climate unbalanced microgrids. Beyond network unbalance, harsh conditions with low irradiance, weak wind speeds, and low temperatures necessitate hydrogen storage systems (HSSs) to address seasonal mismatches between RES generation and demand. This paper proposes a two-stage multi-timescale planning framework that integrates RESs, plug-in electric vehicles (PEVs), battery energy storage systems (BESSs), seasonal HSSs, and a dynamic demand response (DDR) program. In the short term, BESSs are coordinated under slow and fast charging/discharging modes for responding to daily load shifting and peak shaving or sudden demand fluctuations. Smart converters with active/reactive power control are equipped with RES and BESS for local voltage regulation. Furthermore, the proposed DDR program, which combines load reduction and valley filling strategies, enables consumer flexibility based on real-time market signals across seasonal variations. Seasonal HSSs are designed to store excess hydrogen produced from RESs for long-term use across different seasons. The proposed strategy is validated in two stages. The first stage guarantees multitimescale coordination of BESSs, seasonal HSSs, and the DDR. In turn, the second stage optimally plans RESs, BESSs, and HSSs in a unified manner to reduce voltage unbalance and line congestion while maximizing microgrid RES hosting capacity. Simulation results for six interconnected microgrids demonstrate a 12.5% reduction in voltage unbalance, 21% alleviation of line congestion, and a 108% increase in hosting capacity, highlighting the effectiveness of the proposed planning approach for unbalanced RES-rich microgrids.