Economic storage ratio and optimal control of hybrid energy capacity combining stabilized wind power fluctuations with compensated predictive errors

Large wind power fluctuation and prediction error does not meet requirements of State Grid. This paper presents an exceeding error frequency weight (EEFW) method combining three-dimensional optimization method to determine the best economic ratio of hybrid storage capacity. A hybrid energy storage control strategy based on exceeding error integral area (EEIA) method combining four aspect control criteria is formulated. Goal to suppress wind power fluctuation and compensate prediction error is achieved. Firstly, an integrated error control target domain is formulated based on wind power fluctuation suppression with hybrid energy storage to compensate wind prediction error. Secondly, probability characteristics of required compensation error based on probabilistic method is analyzed to determine energy storage capacity, taking into account degree of wind power compensation, energy storage life (charge and discharge times) and economy of the best ratio of hybrid storage capacity, considering four aspect control criteria: multiple scales, EEIA, discharge control strategies and state of charge (SOC) in hybrid energy storage. Finally, it is verified with a 148.5 MW wind farm example. Results show that total hybrid storage capacity is accounted for 23.8% of wind farms installed capacity. Optimal economic ratio for energy type and power type storage capacities is 4:1. Probability of wind power prediction error is limited to ±15% and wind power fluctuation limited to ±20%, with their probability increased from 63.8% to 91.2%, curtailed wind power reduced by 19.8% and hot reserve capacity reduced by 45.2%.