Two‐Layer Optimal Control Strategy of Thermal Power Unit Coupled With Hybrid Energy Storage System in Frequency Regulation

ABSTRACT With the growing penetration of renewable energy, its intermittency and fluctuation have imposed increasingly stringent regulation requirements on thermal power units (TPU). To enhance the automatic generation control (AGC) response performance of TPU, this paper proposes an optimized two‐layer operation strategy integrating hybrid energy storage systems (HESS). Considering the significant regulation delay of TPU and the fast response characteristics of HESS, an upper‐layer control strategy based on nonlinear decomposition is developed for power allocation between the HESS and TPU. The lower‐layer control strategy optimized the power distribution and constraints of the flywheel energy storage system (FESS) and electrochemical energy storage system (BESS), taking into account the lifetime and state of charge (SOC) limitations of the BESS. Finally, the effectiveness of the proposed strategy is verified through simulation studies. The results show that when HESS assists the TPU in frequency regulation, the comprehensive performance index increased from 0.656 to 0.781, indicating a notable improvement in AGC performance. Compared with conventional HESS allocation methods, the proposed strategy reduced the power fluctuations of the TPU and enhanced the comprehensive regulation performance index by 6.4%.