Optimal frequency regulation in nonlinear power networks including turbine-governor dynamics

Motivated by an increase of renewable energy sources we propose a distributed optimal Load Frequency Control scheme achieving frequency regulation and economic dispatch. Based on an energy function of the power network we derive an incremental passivity property for a well known nonlinear structure preserving network model, differentiating between generator and load buses. Exploiting this property we design distributed controllers that adjust the power generation. Notably, we explicitly include the turbine-governor dynamics where first-order and the widely used second-order dynamics are analyzed in a unifying way. Due to the non-passive nature of the second-order turbine-governor dynamics, incorporating them is challenging and we develop a suitable dissipation inequality for the interconnected generator and turbine-governor. This allows us to include the generator side more realistically in the stability analysis of optimal Load Frequency Control than was previously possible.