Modified-multi stage LQR (M-MSLQR)UPFC controller for inter-area oscillations damping-design and analysis

This paper presents analysis and design of modified-multi stage LQR (M-MSLQR) unified power flow controller (UPFC). A systematic analysis of M-MSLQR UPFC has been presented utilizing state space model developed in the generalized framework for two area system. An improved design concept is proposed as M-MSLQR UPFC over MSLQR which results in relatively low peak overshoot/undershoot and settling time of all states. The proposed controller considers state predominant approach with real part as well as the imaginary part of the eigenvalues of the system for the selection of Q matrix. This method gives fast tracking of all system state variables for a given perturbation. PSO is used for initial tuning of input control parameters of UPFC. The approach is modular and general enough to include any subsystem with detailed representation. The controller proposed can readily be extended to multi-area system with some augmentation including interface of system dynamics. The simulation result shows improved performance and may be used for better stability and reliability of power system.