Enhancement of voltage stability by coordinated control of multiple FACTS controllers in multi-machine power system environments

This paper presents the implication of adding various FACTS controllers in multi-machine power system environment in coordinated control manner for enhancement of voltage stability requires an appropriate mathematical model of the power system and the FACTs controllers such as a Static Var Compensator (SVC) and Thyristor Controlled Series Capacitor (TCSC). The DAE (Differential Algebraic Equation) methodology for multi-machine system has been is used in this paper. Event tough the SVC model has been incorporated in DAE model, TCSC model has not been incorporated. So the purpose of this paper is to derive a TCSC model such that it can be incorporated in DAE model of power system. Further in a large power system there may be more than one FACTS controllers, therefore it is important to develop a combination of series and shunt FACTS controllers that can be incorporated in the DAE model in Modular fashion. The models developed have been utilized for eigen-value analysis of IEEE 9-bus 3-machine power systems. There are many commercial packages available for transient simulation and analysis of power systems. The transient simulation packages (e.g. EMTDC/PSCAD) allow incorporation of FACTS controller models. This facility is however not available in the small signal stability analysis packages. The objective of this paper is to develop a methodology to incorporate FA CTS controllers in a modular fashion to facilitate eigen-value and voltage stability analysis using MATLAB toolbox.