Distributed Automatic Load-Frequency Control with Optimality in Power Systems

With the increasing penetration of renewable energy resources, power systems face a new challenge in balancing power supply and demand and maintaining the nominal frequency. This paper studies load control to handle this challenge. In particular, a fully distributed automatic load control algorithm, which only needs local measurement and local communication, is proposed. We prove that the control algorithm globally converges to an optimal operating point which minimizes the total disutility of users, restores the nominal frequency and the scheduled tie-line power flows, and respects the thermal constraints of transmission lines. It is also shown that the convergence still holds even when inaccurate system parameters are used in the control algorithm. Lastly, the effectiveness and optimality of the proposed algorithm are demonstrated via numerical simulations.