Damping of Interarea Oscillations of a Wind Farm based Multimachine Power System using an Unified Power Flow Controller

An adaptive second order sliding mode control strategy is proposed for of the Series Synchronous Static Compensator (SSSC) of the Unified Power Flow Controller (UPFC) which is installed in a multimachine power network penetrated with a Doubly Fed Induction Generator (DFIG) based wind power. The proposed controller utilizes the instantaneous power components of the SSSC instead of the conventional current or torque components (thus the dynamics of the phase lock loops (PLL) is avoided) and has been made to adapt according to the diverse operating conditions of the network. This feature has made the proposed controller to be more significant (in terms of improvement of the transient stability) as compared to the conventional techniques as both the inter area as well as local oscillations have been improved. The overall power system network has been modeled in MATLAB/Editor environment, and the proposed controller has been investigated for both lower and higher wind penetration conditions and the results obtained are satisfactory.