Optimal robust stabilizer design based on UPFC for interconnected power systems considering time delay

Abstract

A robust auxiliary wide area damping controller is proposed for a unified power flow controller (UPFC). The mixed H2 / H∞ problem with regional pole placement, resolved by linear matrix inequality (LMI), is applied for controller design. Based on modal analysis, the optimal wide area input signals for the controller are selected. The time delay of input signals, due to electrical distance from the UPFC location is taken into account in the design procedure. The proposed controller is applied to a multi-machine interconnected power system from the IRAN power grid. It is shown that the both transient and dynamic stability are significantly improved despite different disturbances and loading conditions.

Keywords

• UPFC
• mixed H2 / H∞
• LMI
• wide area
• power system oscillations
• time delay