Dynamic Stability Improvement of Power System with Simultaneous and Coordinated Control of DFIG and UPFC using LMI

Abstract

This paper presents enhancement of power system dynamic stability while equipped with both unified power flow controller and doubly fed induction generator by using LMI technique. We have used all UPFC (Unified Power Flow Controller) main basic PI controllers and its POD (Power Oscillation Damping) supplementary controller. More complete model of DFIG (Doubly Fed Induction Generator) and both RSC (Rotor Side Converter) and GSC (Grid Side Converter) dynamics with their controllers have considered too. These two devices controllers have simultaneously co-ordinate and optimized with compromising between their control variables parameters. PSO (Particle Swarm Optimization) algorithm has used to optimize an objective function based on Eigen values and damping ratio to reach to best parameters and variables of controllers of both of UPFC and DFIG. LMI (Linear Matrix Inequality) have applied to whole system linearized model to reach to optimally modified eigenvalues. Within steady state and dynamic study we considered practical line thermal capacity and UPFC power rating too. Simulation results in 39-bus 10-machine Ne-England power systems ilustrate the capability of applied method. The results demonstrated that coordinated control of these two devices beside using LMI tend to more damping of system modes oscillation and more stability in power system.