Small signal stability analysis of grid connected wind energy conversion systems

Distributed Generation (DG) is a small form of generation in less than tens of MW range from renewable energy sources. Wind Energy Conversion System (WECS) based on constant speed squirrel cage induction generator is a popular system in India. Small signal stability analysis is very much essential to study the oscillations which normally exist in a power system and leads to unstable operation when small disturbances are applied. Basically, synchronous machine rotor is prone to weakly damped (low frequency) oscillations. But damper winding provides less damping for low frequency oscillations with small amplitude. It justifies the need for Power System Stabilizer (PSS) as a damper for oscillations. So, this work is intended to find the effect of wind energy conversion system on small signal stability conditions of conventional power system with synchronous generators with PSS. Eigen value analysis is conducted after developing a Differential-Algebraic model (DAE) in power balance form and tested on a modified 3 synchronous machine - 9 bus system with constant speed wind turbines.