Second-Order Sliding Mode Design Based on the Integration of Proportional-Integral and Nonlinear Controllers for Load Frequency Control

This article addresses the load frequency control (LFC) problem of control-area-partitioned power networks. An equivalent generator with second-order turbine-governor dynamics is utilized to model each control area, and power flows establish nonlinear couplings between control areas. As a consequence of the integration of the proportional-integral (PI) controller and the nonlinear controller, a novel suitable sliding manifold for enhancing dynamic performance is first proposed. Then, a decentralized second-order sliding mode (SOSM) controller is designed for LFC in power networks, which regulates the frequency and sustains the net inter-area power flows at the predetermined values. The simulation results demonstrate the efficacy of the proposed control strategy.