Nonlinear Backstepping Control Design for stabilizing Synchronous Machine-Infinite Bus System using Reactive Power Compensation Device

Maintaining a stable generator during operation is crucial for the entire power system to avoid any damage that could disrupt the service. As power systems are usually vulnerable to inevitable external and internal noises, it is required to design a proper controller that can return the system to its original state after the source of noise is cleared. Back-stepping controllers have received increased interest due to a number of advantages such as a systematic way of deriving the control law, guaranteed global performance, high robustness, and satisfactory transient characteristics. In this paper, a Nonlinear Backstepping approach is utilized to design a controller that stabilizes a Synchronous Generator connected to an Infinite Bus system by injecting a reactive current. The objectives of this controller are to stabilize the rotor angle and improve the transient stability, and mitigate any oscillation that may occur in the system, such as faults or mechanical disturbances. Therefore, the model considered herein utilizes shunt compensating impedance to represent the amount of reactive current to be injected into the grid in order to meet those objectives. Correspondingly, a third-order model of a constant flux synchronous generator connected to an infinite bus, with reactive power compensating device, is presented. With the goal to maintain the stability of the rotor angle under any circumstances, the controller is designed to incorporate the effect of uncertainties in the model. Simulation results prove that the controller is capable of stabilizing the generator rotor and suppressing transient oscillations that arise under abnormal conditions.