Convergence rate controllable event-triggered robust load frequency control for multi-area power systems

Abstract

This paper investigates the load frequency control (LFC) for multi-area power systems with modeling uncertainties and communication topology changes. A group of convex polytopes is firstly employed to model the uncertainty of power systems. Since the topology variant events are barely impossible to be explicitly detected in reality, the dynamic topology scenario is described as a finite switching set with two kinds of time-varying switching signals, i.e., a random sequence, and a transition probability unknown Markov chain. Based on the above descriptions, a distributed robust control law is proposed to reduce the frequency deviation of each sub-power system. For further alleviating the controller burden, an event-triggered command updating scheme is designed. The proposed LFC strategies not only guarantee the exponential stability of each subsystem but also coordination with the overall power grid. Moreover, only seldom necessary control commands are updated while the rest commands are suspended, meanwhile, the convergent rate of overall power system is also specifiable. Numerical examples are provided to demonstrate the effectiveness of the proposed methods.