Power systems voltage stability enhancement using nonlinear controller

In this paper, a new nonlinear controller based on combination of backstepping method technique and input-output feedback theory, called modified backstepping is proposed for a single machine infinite bus (SMIB) network. The main goal of controller design is to control the stem position of turbine´s valve and excitation voltage, simultaneously. This task enhances the transient stability and improves voltage regulation of power system under a symmetrical three-phase short circuit fault. The obtained results through simulations are compared with the behavior of a generator working with classic PSS & AVR. The results demonstrate that the proposed nonlinear controller are very effective and can ensure the transient stability under a large sudden fault.