Impact of Photo Voltaic generation control on multi machine Small signal stability

The modeling and analysis of the impact of Solar Photovoltaic (PV) on the small signal stability of power system are explored. The analysis provides explanations of the impact of the closed-loop control on the power system stability. Two system models, Single Solar Infinite Bus (SSIB) system and solar connected multi- machine system are considered. In model of PV, module variable are algebraic that is, they change instantaneously and the modeled dynamics are those of the power converter controller. The discussion considers maximum power point tracking, dc link voltage and current controller. In case of SSIB sensitivity to different weather conditions such as irradiance, temperature is studied. Also sensitivity to different power system conditions such as voltage variation, reactive power support from solar is studied. In multi-machine case impact of different active and reactive power injection levels is analyzed. The observations and conclusions obtained from eigenvalue, participation factor analysis suggest that even though the PV generation system dynamic do not participate into low frequency oscillation modes, its control can influence small signal damping depending based on its location in the system.