Optimal Energy Storage Configuration for Primary Frequency Regulation Performance Considering State of Charge Partitioning

The proportion of renewable energy in the power system continues to rise, and its intermittent and uncertain output has had a certain impact on the frequency stability of the grid. Therefore, a multi-type energy storage (ES) configuration method considering State of Charge (SOC) partitioning and frequency regulation performance matching is proposed for primary frequency regulation. Firstly, the Automatic Generation Control (AGC) signal is decomposed and reconstructed using the variational mode decomposition (VMD) method. Specifically, by combining the charge and discharge characteristics of Li-ion battery and flywheel energy storage (FES), component signals of different frequencies are allocated to different ES systems. Secondly, a multi-type ES capacity allocation optimization model considering SOC partitioning is developed, with the objective function being the minimization of the whole life-cycle planning cost of ES. Finally, based on actual data from a region in North China, the proposed method is verified by analyzing case studies under different scenarios. The results demonstrate that the method can effectively reduce computation time, optimize ES operating conditions, and thus lower the whole life-cycle planning cost of ES.