Influence of renewable energy based microgrid on low frequency oscillation of power systems

Increase proliferation of microgrid (MG) technologies with extended use of renewable energy sources (RES) can affect the system stability performance since dynamic characteristics of this kind of MG are different from conventional generation. Sharing certain portion of or entire generated power from synchronous generator with MG results in decrease of total system inertia. On the other hand, connecting RES based MG near a central load eventually enhance system performance due to improvement in reliability, reduction of power loss and congestion on transmission line. This paper investigates the impact of RES based MG on local and inter-area oscillatory modes of power systems. This study focuses on low oscillatory eigenvalues in the frequency range of 0.1-2 Hz. Eigenvalues analysis is performed to observe damping ratios and stability margins of the system due to MG integration. Furthermore, time domain simulation is then carried out to validate the result from eigenvalues analysis.