Load-frequency control scheme for power systems using smoothed switching structure theory

A design scheme of smoothed switching structure theory based load-frequency control for power systems including parameter uncertainties is presented in this paper. However, knowledge about the bounds of the parameter uncertainties is required for controller design. The basic concept and design scheme of switching structure control are briefly discussed. The design process of load-frequency control using a linearized model with parameter uncertainties, which are obtained by simultaneously changing parameters by 55% to 95% from their nominal values, consists of key steps including both approximating continuous control law with sliding mode property, and the special switching hyperplane to enhance the system stability degree. The simulation results show that the proposed controller can not only improve the dynamic stability of the power system but also achieves good performance for all admissible uncertainties.