Small-signal stability evaluation of a non-autonomous microgrid system

A microgrid comprised of wind, PV, and fuel cell generation systems along with a micro-alternator and a storage system is considered in this study. The small signal behavior of the system is investigated considering the real part of the dominant eigenvalues. The impact of the participation of the distributed generation sources on the small-signal stability has been investigated. While it is essential that participation of the alternator should be a minimum from economic and environmental considerations, it has been observed that its participation is essential for satisfactory operation of the grid in terms of maintaining frequency of the system as well as from general stability considerations. Too little contribution from the micro-alternator may drive the system unstable even under small disturbance conditions. Penetrations from wind and PV systems help stability, while the fuel cell tends to have destabilizing effect at heavier loads. Eigenvalue based small-signal stability of the system has been verified through response obtained by the dynamic model.