Robust load‐frequency control in interconnected power systems

Abstract

This study describes a robust load-frequency control (LFC) scheme in a two-area interconnected power system with uncertain disturbances. A sector-bounded H∞ control approach is used for compensating of the non-linearities based on a minimum order dynamic LFC model to avoid the complexity of a high-order model. The simulation in time domain from the use of the proposed controller has been compared with the use of a conventional proportional–integral (PI) type controller affected by the same load change. The simulated results have proved the significant improvement over the PI controller and have verified the effectiveness of the proposed robust H∞ controller which can minimise the frequency deviations significantly. This approach treats the tie-line power exchanges in the presences of external disturbance, parameter uncertainties and accidental crashing of generating units as the structural or model uncertainties discussed in this study. Simulation results also show that the proposed H∞ controller guarantees robust performance and fast response under a wide range of operating conditions and system uncertainties.