Flexible AC Transmission System (FACTS) Controllers are useful in improving power system reliability and relieving congestions in power systems, which are particularly important in deregulated electricity markets using locational marginal prices and thus are of national interest. The proposal addresses the development of a common modeling framework suitable for implementing both thyristor-controlled and voltage-sourced converter (VSC) based FACTS Controllers. This common power system model will have the ability to include injected series voltage sources, which can circulate active power with other injected voltage sources, thus expanding the capability of power system models. In this framework, network sensitivities can be readily computed and be used to evaluate the effectiveness of FACTS Controllers for steady-state power transfer and voltage support, and transient power and voltage swings. The proposed research will develop the FACTS Controller models and the sensitivity computation tools. The models and tools will be used in determining the optimal FACTS Controller dispatch for a given power transfer condition, as well as evaluating the maximum transfer capability over a congested transfer path. In interarea-mode damping control design, they will be used in computing the controllability of a FACTS Controller; the observabilities of potential input signals for the controller, and the inner-loop gain limitations of the individual input signals. In addition, the use of the common FACTS Controller model in state estimation will be investigated.
