Multi-time-scale coordinated ramp-rate control for photovoltaic plants and battery energy storage

The variability of solar irradiance with a high ramp rate may lead to fluctuation in the output of photovoltaic (PV) plants and burdens the power system regulations. A novel control method coordinating the solar PV plants and the battery energy storages (BES) is proposed, aiming at minimising the gap between multi-time-scale ramp of solar PV station and the grid code requirement. The proposed control method combines the computationally efficient feedback control and the mathematical optimisation. Both the short-term forecast and the historical samples are utilised to regulate the output of the PV plants and BES. The state-of-charge reference is adapted by the proposed control in real-time operation for the better performances. The necessary solar power curtailment is investigated with limited BES capacity. The effectiveness of the proposed control method is comprehensively verified by simulations based on real-world measurements of solar PV power under various BES capacity and ramp range requirements.