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.