Combining voltage stability margin and electromechanical damping for FACTS

In power systems are normally localized linear controllers placed at several subsystems located in different geographical zones. In addition, there have been introduced new technologies of non-linear control, with applied methodologies of feedback linearization, where all the system is transformed to a linear system. Nevertheless, the decentralized scheme is not possible because all the information of the entire system is required when that transformation is done. That is why it must be developed a controller that maintains the decentralization at the same time as the robustness. The procedure detailed in this paper consists of the utilization of reduced dynamical models computed at each FACTS device useful for the computation of supplementary controls. So, a decentralized model is done from a linear model, where there are the local controls for each device and a central control that gives the reference. The paper also describes the methodology used for computing optimal LQG/LTR decentralized controls for FACTS and, previously, it is outlined the problem to locate the FACTS devices and know its dimensions.