Design of Upfc Based Damping Controller for Robust Stabilization of Power System Low Frequency Oscillations Using Lmi Technique

This paper presents the design of Unified Power Flow Controller (UPFC) based damping controller for damping of power system low frequency oscillations under dynamic uncertainty. Detailed investigation have been carried out by previous researchers considering the four alternatives of UPFC based damping controller namely modulating index of series inverter (mse), modulating index of shunt inverter (msh), Phase angle of series inverter (δse) and phase angle of the shunt inverter (δsh). The damping controller design is formulated as an output disturbance rejection problem based on the mixed sensitivity formulation. The problem is posed in the linear matrix inequality (LMI) framework. A Single Machine Infinite Bus (SMIB) system employing UPFC is considered to illustrate the effectiveness and robustness of the proposed controller over a wide range of operating conditions. The MATLAB simulation result shows good damping and robustness.