Overview of Steady-state Modeling and Optimal Operation of Power System with FACTS

With the development of power grid and renewable energy, power flow over-limit has become an increasingly serious problem which threats security and stability of the system. Flexible alternating current transmission systems (FACTS) provide flexible adjustment of the network structure and parameters, which improve transmitted power of lines and enhance stable operation of the system. It is important to utilize the maximum ability of FACTS devices and achieve optimal operation of the power system. Typical and the most powerful FACTS devices, unified power flow controller (UPFC), interline power flow controller (IPFC) and hybrid power flow controller (HPFC), are firstly introduced, topologies and characteristics are also summarized. Secondly, different equivalent models of FACTS are introduced, and their characteristics are discussed. Finally, models and solution methods for optimal operation of the system with FACTS are introduced, then the direction for further research is prospected.