Fractional-order Disturbance Observer Based Secondary Frequency Control for Power Systems with Battery Energy Storage

With the gradually increasing proportion of renewable energy in power systems, frequency stability is facing a huge challenge. Battery energy storage (BES), as a high-quality frequency control resource, has become one of the indispensable means for load frequency control (LFC) of the power system. How to design an advanced load frequency controller and BES control strategy is the key issue for frequency regulation. In this paper, an improved fractional-order PID controller based on the fractional-order disturbance observer is proposed to solve the above problem. then, the operating strategy for battery energy storage is constructed to achieve accurate regulation of frequency, according to the real-time area control error signal and state of charge for the battery energy storage. next, an interconnected control model considering the participation of battery energy storage is built. finally, the disturbance rejection performance and robustness of the controller have been verified by step disturbance, random disturbance, and Monte Carlo random experiments.