Application of optimal stabilizer and variable structure controller for power system stability with free chattering

This paper proposes two novel techniques for improving the dynamic stability of power system. The first technique utilizes the optimal stabilizer with preview steps. The second technique makes use of the variable structure system and employs the generator speed to obtain a stabilizing signal to increase the damping torque of the synchronous machine. Supplementary stabilizing signals are also introduce into the power system to increase the damping torque of the synchronous machine. This improves the transient stability of the power system. The plant augmentation method is used to solve the existing control chattering problem. Augmenting the plant by a pure integrator places control chattering at the augmented plant input instead of the original plant input. The optimal stabilizer is synthesized and implemented and its applicability and robustness are demonstrated. The simulation results demonstrate that the proposed two techniques yield a good dynamic performance with less overshoot and shorter settling time in step response. These two techniques can be used as effective mean of increasing the damping torque and hence improving the dynamic stability of the power system.