Key Laboratory of Modern Power System Simulation and Control & Renewable Energy Technology, Ministry of Education (Northeast Electric Power University), Jilin 132012, China
The battery energy storage is regarded as a high-quality frequency regulation resource because of its fast power throughput. However, excessive charging and discharging will cause insufficient frequency regulation capability of the energy storage. This paper proposes a control strategy to improve the performance of primary frequency regulation (PFR) with energy storage system. Firstly, the deadband of energy storage is limited within the deadband of units, and the impact of the deadband variation of energy storage on frequency is analyzed with the grid frequency characteristics. On the basis of this, the strategy of PFR with energy storage based on weight factors and state of charge (SOC) recovery is proposed. For the condition that the frequency fluctuation exceeds the deadband of the energy storage, a calculation method of frequency regulation coefficients for energy storage is proposed, which is used to avoid excessive charging and discharging of batteries. Meanwhile, two weight factors of the virtual inertia control and the virtual droop control are introduced, whose ratios vary with the frequency, and then the control method of frequency regulation is designed. For the opposite condition that the frequency fluctuation does not exceed the deadband of frequency regulation for the energy storage, a method of the SOC recovery is put forward, which takes the need of the energy storage recovery and the grid tolerance into account. Simulation results indicate that the proposed strategy can improve the frequency fluctuation of the grid and the SOC of the energy storage.
This work is supported by National Natural Science Foundation of China-State Grid Joint Fund for Smart Grid (No. U1766204) and Central Government Guides the Basic Research Project of the Provincial Key Laboratory of Local Science and Technology Development Funds.
|||LI Junhui, HOU Tao, MU Gang, et al. Primary Frequency Regulation Strategy with Energy Storage System Based on Weight Factors and State of Charge Recovery[J]. Automation of Electric Power Systems,2020,44(19):63-72. DOI:10.7500/AEPS20200320002|