Load frequency control scheme design considering flexible disturbances

Good power quality cannot be achieved without the frequency stability of power systems. Nevertheless, with the large-scale integration of highly flexible renewable energy sources (RESs) such as wind and solar energy, frequency stability is threatened by RES-generated disturbances due to their volatility and intermittency especially in the very short time scale. Therefore, a new frequency control scheme should be designed to attenuate these highly time-varying disturbances. In this study, load frequency control (LFC) considering flexible RES suppression is investigated. Inspired by the idea of disturbance estimation and compensation, a novel active disturbance rejection (ADR) scheme is proposed. Unlike previous ADR-based LFC schemes, the proposed one can significantly reduce estimation errors via a novel extended state observer. Then a sliding mode control scheme is used to force the area control error to slide along the equilibrium, thus significantly attenuating the power imbalance. Simulation results show the effectiveness of the proposed schemes.