Decentralized extended-backstepping control of power systems

In this paper backstepping controller with additive nonlinear damping term is applied for stability enhancement of multi-machine power systems through excitation control. The decentralized control scheme is practical in systems especially when couplings are handled appropriately. Couplings between generators through transmission lines are modeled and considered as external disturbance through each plant. Controller design, extended-backstepping, is based on a recursive technique to obtain stabilizing control via Lyapunov function. Additive nonlinear damping (extended term) is used to counteracts the effect of disturbance. Parameter settings for the controller are obtained with particle swarm optimization technique. Results on 50 machines 145 buses show that extended-backstepping controllers effectively stabilize the system for severe contingencies in comparison with conventional power system stabilizer