Model And Method For Power Flow Calculation Of Power System With FACTS

As deregulation of the electric industry, constant increase of electric load and more attention to the security of power system, flexible AC transmission system (FACTS) based on high power electronic elements is becoming the focus that people study. FACTS devices can flexibly and rapidly control power system, improve transfer capability of transmission networks, strengthen the economy, reliability and security of power system, and make power system have of higher controllability. Therefore, a corresponding, correct and suitable model for steady-state power flow calculation is the foundation of the research and control to various kinds of FACTS devices. At first, the definitions, functions and classification of FACTS are briefly introduced in this paper, and then basic principles of several kinds of main promising FACTS devices are explained. Various kinds of equivalent circuits of FACTS devices and models for steady-state power flow calculation have been proposed and the corresponding algorithms have been developed by other research scholar, so a relatively detailed analysis and comparison to these models and algorithms are made in the following chapter of this paper, and the main factors that influence the convergence speed and convergence performance of power flow calculation of power system with FACTS devices also are discussed, and the current problems that need to be resolved in this research region are pointed out. This paper presents a new steady-state model and algorithm for power flow calculation of power system with FACTS devices, and expatiates their principles and deriving processes. The capacitance of line to ground is considered in the model. This model based on power injection method, is intuitive, convenient and versatile, and can be used for various functional modes of FACTS devices and all FACTS devices. This algorithm based on the Fast Decoupled Load Flow (FDLF), has merit of fast speed, and is easily carried out. By using power injection as the additional state variable, it is apt to confirm better initial value of the control parameter of FACTS devices and state variable of system. Therefore, convergence performance of algorithm gets improved. Finally, by utilizing a common 5-bus system and IEEE 30-bus system with UPFC as example, the simulation results of the two systems indicate that the proposed method is reliable, efficient and accurate.