Multi-timescale Rolling Dispatching Strategy for Wind-photovoltaic-storage Hybrid System

Due to the uncertainty and fluctuation of photovoltaic (PV) and wind power, the wind-photovoltaic-storage (WSS) hybrid system does not track the planned command issued by the grid well enough. This article propounds a multi-timescale rolling dispatching strategy for WSS combined operation, aiming to improve the problems of poor tracking effect of ultra-short-term dispatching and excessive power compensation pressure of the energy storage system (ESS) in the real-time control stage. In the ultra-short-term dispatching stage, the dispatching target is to fit the planned command curve to the maximum extent. Then, considering the states of ESS, an ultra-short dispatching model is established to obtain the ultra-short power output commands of wind turbine (WT), photovoltaic and ESS in a rolling dispatching manner. In the real-time control stage, the real-time predicted power and the measured value of WT-PV are used to fine-tune the ultra-short-term output command for the current dispatching cycle. Finally, the “dual-battery groups method”, which aims at the dynamic balance of power of energy storage units, is used to allocate the real-time planning commands among energy storage units. This paper simulates the practical running data of a wind power station and PV power station in Northwest China. The results show that the proposed method can track the power command well. Reduce the impact of ultra-short-term power prediction errors. The discharge and charge frequencies of the ESS in the real-time stage are effectively reduced, and can make each energy storage unit achieve the dynamic balance of power, which testifies the applicability of this strategy.