Fast frequency recovery-oriented distributed optimal load frequency control: An active disturbance rejection control approach.

With high penetration of renewable energy sources in nested multiple-microgrids, conventional solutions for the integration of load frequency control and economic dispatch may degrade frequency control performance and decrease operational economy. In this paper, a fast frequency recovery-oriented distributed optimal control strategy is proposed to deal with these problems. Firstly, a partial primal-dual gradient algorithm is dynamically integrated with an active disturbance rejection control algorithm (instead of conventional Proportional-Integral (PI) controller) to realize the fast frequency recovery and enhance anti-disturbance capability. As a result, frequent adjustments of resources can be avoided and this is crucial in extending the life cycles of batteries. Then, based on the above integration, the distributed optimal control law is derived, which is independent of load measurement and fully distributed, to coordinate the microgrids to share their power economically during the frequency regulation process. This can also relieve the communication and computation burden of the system. Finally, a set of numerical simulations is presented and the effectiveness of the proposed distributed optimal control is verified by the obtained results, which include a comparison with the conventional distributed PI-based optimal control strategy.