A novel load frequency control strategy for renewable energy power system by coordinating energy storage and thermal power

Energy storage has been commonly used in the power system with high renewable energy penetration to improve its load frequency control (LFC) performance. In this paper, a novel LFC strategy for renewable energy power system (REPS) is developed by coordinating energy storage and thermal power. Firstly, a novel command generating algorithm for energy storage control is proposed through wavelet packet decomposition (WPD), and the optimal decomposition layers considering traditional thermal power responding time is also presented. By doing so, the energy storage and thermal power can achieve reasonable cooperation according to their respective responding ability. Secondly, a discrimination method for disturbed area based on back propagation neural network is put forward, which is then be used as a flag to indicate the energy storage taking part in this response or not. By doing so, the energy storage is blocked from responding to cross-regional disturbances. Furthermore, a new LFC strategy is designed by revealing the relationship between controller inverse and area control error (ACE), by which the automatic generation control (AGC) command is effectively outputted for energy storage and thermal power coordination. Finally, a case study in a two-area interconnected power system is simulated to verify the effectiveness of the proposed scheme.