On Stability of Distributed-Averaging Proportional-Integral Frequency Control in Power Systems

Distributed consensus-based controllers for optimal secondary frequency regulation of microgrids and power systems have received substantial attention in recent years. This letter provides a Lyapunov-based proof that, under a time-scale separation, these control schemes are stabilizing for a wide class of lossless and stable nonlinear ODE power system models, and under weak assumptions on (i) the objective functions used for power allocation, and (ii) the graph topology describing communication between agents in the consensus protocol. The results are illustrated via simulation on a detailed test system.