Analyzing the Effects of Nonlinear Factors on the Power Systems Behavior

The non-linear factors will create the nonlinear interaction between linear modes; therefore, it has very important effects on increasing the complexity behavior of power systems under stressed condition. This paper, after a brief review of non-linear typical analysis methods, i.e. linear modal method, normal form method and modal series method, surveys the approximate solutions obtained via these methods. To do so, we analyze proximity measure of the simulation results of different methods calculated in the power system with Unified Power Flow Controller (UPFC). The results show that the modal series method is more useful than other typical methods in analyzing the nonlinear systems.