Decentralized H∞ control for stabilizing multi-machine power systems

This paper applies the decentralized H^∞ control theory to interconnected multi-machine power systems. The idea is to design a local controller for each machine model with global sub-optimal H^∞ control performance with considering the interactions among multi-machine systems. The sub-optimal H^∞ state feedback controller for each machine is calculated by the algorithm based on the linear matrix inequality (LMI). The control input for each machine is implemented by supplementary excitation control. The disturbance to each subsystem is modeled by perturbation of the terminal voltage, which is raised by the simultaneous reactance change of the transmission line. The proposed control design scheme is applied to a three-machine loop system and a three machine radial system. The frequency responses and transient responses for each machine and the global system are evaluated by numerical simulations