Application of FACTS devices to improve steady state voltage stability

This paper examines the coordinated application of flexible AC transmission systems (FACTS) technology to extend steady-state voltage stability margins in electric power systems. A systematic analytical methodology based on the concept of modal analysis of the modified load flow equations and the study of controllability and observability characteristics of the equivalent state model is used to identify system areas prone to voltage instability, as well as to determine the most effective locations for placement of FACTS controllers. Results obtained using a practical system representative of the Central American interconnected network are presented illustrating the application of FACTS technology.