SMALL SIGNAL STABILITY OF DOUBLY FED INDUCTION GENERATOR CONNECTED WIND POWER SYSTEMS

Abstract

The global electrical energy consumption is rising and there is steady increase of demand on power generation. So in addition to the conventional power generation alternative energy sources are being integrated into power systems. The worldwide demand for more diverse and greener energy supply has had a significant impact on development of wind energy in the last decades. Doubly Fed Induction Generator (DFIG) is one of the mostly used asynchronous generators for wind energy application because of its advantages like reduced mechanical stress and sub and super synchronous operation. With the increased penetration of these in Power Systems stability issues are of major concern. This dissertation deals with the modeling and small signal stability analysis of DFIG connected to power systems. The modeling of DFIG connected Power systems consists of developing a set of Differential Algebraic Equations (DAE) which include system state equations and algebraic equations are presented. A 7th' order model for synchronous machine with IEEE type-I exciter has also been presented. The Eigenvalues and the participation factors of DFIG connected to an infinite bus are calculated. The inherent oscillating modes of DFIG are determined. The variations of eigenvalues with respect to various system•parameters are also investigated. The stability of SMIB is determined by the analysis. This investigation is useful in understanding the machine inherent dynamics. Finally the DFIG is compared with the synchronous generator by taking an 8 bus power system network.