Small signal stability analysis of grid connected Photo Voltaic distributed generator system

Distributed Generation is a small source of electric power conversion from non-conventional energy sources such as Photo Voltaic system (PV), wind, Fuel cell etc. Small signal stability analysis is very much essential to study the inter-area and intra area oscillations which normally exist in a power system. But, it leads to unstable operation when small disturbances are applied. Normally, mechanical part of a synchronous system is intrinsically prone to weakly damped oscillations and the damping of these oscillations must come from other sources, such as damper windings and the machine´s controllers. Because power system oscillations have frequencies in the order of a few Hz and of rather small amplitude, hardly any damping is provided by the damper windings, leaving the controllers and the rest of the power system as the main contributors to the damping of the rotor speed oscillations. So in this paper, Power system stabilizer (PSS) is used for providing damping torque. This paper examines the effect of PV sources on small signal stability conditions of conventional power system with Synchronous Generators (SG) along 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 [10] with PV converters.