Load Frequency Control Method for Cyber-Physical Power Systems With 100% Renewable Energy

In 100% renewable energy power systems (REPSs), the frequency deviation is independent of the storage and release of rotor kinetic energy, and the essence of frequency control changes from energy balance to power balance. Thus, conventional LFC schemes are no longer applicable for 100% REPSs. To realize constant frequency operation of 100% REPSs, in this article, a novel load frequency control (LFC) scheme is proposed, for the first time. Furthermore, communication delays and packet losses are also considered. The proposed LFC scheme consists of two parts: a cascaded extended state filter (CESF) and a robust decision-making model (RDMM). First, the Padé rational polynomial is utilized to approximate the delay factor, based on which the LFC model with delays of the 100% REPS is established. Next, combining the Kalman-Bucy filter and extended state observer, the CESF is proposed to accurately estimate load variations. Then, taking both the renewable energy variation and the probability of packet losses into account, the RDMM is proposed to formulate the real-time power balance scheme. Finally, the proposed LFC scheme is verified on a modified IEEE 39-bus system with a pattern of 100% REPS.