Tube-based Distributed MPC for Load Frequency Control of Power System with High Wind Power Penetration

Distributed model predictive control is an effective method to realize the power system load frequency control (LFC). However, the frequency stability of the multi-area power system becomes quite challenging with incorporating high wind power penetration, as it brings strong uncertainties. This paper proposes a tube-based distributed model predictive control (DMPC) for the LFC of the interconnected power system. In the scheme, the high penetrated wind power is taken as an independent generation area, in which the virtual inertia control system is incorporated for enhancing the inertia response. The wind turbines are operated under the de-load mode for participating in the frequency regulation, just like the thermal power plants. The tube-based DMPC consists of a nominal MPC and an ancillary feedback law, which aims at restraining the wind speed uncertainty. The neighboring areas' information is incorporated into the ancillary controller as a feedback term, realizing effective coordination between generation areas. The input-to-state stability of the power system under the proposed tube-based DMPC can be guaranteed based on the Schur property and the bounded disturbance condition. The simulation on a four-area interconnected power system demonstrates the effectiveness of proposed algorithm on alleviating the frequency fluctuation caused by varying load and uncertain wind speed.