A comparative study on voltage stability analysis of single machine infinite bus system using Lyapunov methods

Power system is a typical nonlinear system and voltage stability is an important subject of research in power system since long time. Stability analysis of a nonlinear system is a challenging task and the second method of Lyapunov is an important tool for the prediction of stability for nonlinear systems without finding the exact solution. Lyapunov's second method based on the Lyapunov functions obtained from variable gradient method and Krasovskii's method is applied to analyze the voltage stability of the single machine infinite bus power system, separately. The stability of the system under study is predicted by observing the variation in the energy content of the system with different values of generator angles. Finally, a comparative study has been carried out for both the methods and the Krasovskii's method is found to be superior to that of voltage gradient method.