Modelling of Doubly Fed Induction Generator in a Multimachine AC System with sMES Control

Abstract

Doubly fed induction generators (DFIG) are preferred over other variable speed wind generators because of their better performance characteristics. However, their converters fail to operate properly at very low grid voltages. A method of improving the performance of the doubly fed machine in a multimachine AC system using superconducting magnetic energy storage (SMES) system is proposed in this article. Model of the asynchronous DFIG and synchronous multimachine system dynamics, including the SMES, is developed. Control of real and reactive power of the SMES is utilized for riding the low-voltage conditions. Studies made show that SMES controlled DFIG system can, not only help ride through extremely low-voltage conditions, also provides damping to power transients. The amount of control required by the SMES has been observed to be significantly low. The SMES control is also shown to provide added stability to the multimachine AC system.