Survivability of Synchronous Generator-Based Distributed Energy Resources for Transient Overload Conditions in a Microgrid

A synchronous generator-based distributed energy resource (DER) is commonly employed in microgrids due to its low cost and simple controls. However, there are many challenges to the DER operation when it is sized for supplying the critical loads alone in a microgrid. In particular, the DER would experience an overload condition during the microgrid transition from grid-connection to islanded operation, when the noncritical loads are also supplied momentarily. Therefore, it is very important to have a clear understanding on the survivability of a synchronous generator-based DER for transient overload conditions. Recently, experimental tests on survivability of the DER were carried out in the Consortium for Electric Reliability Technology Solutions Microgrid Testbed at American Electric Power. In this paper, an in-depth analysis of the synchronous generator-based DER operation during transient overload conditions is presented. The key relationships governing the system dynamic behavior of synchronous generator-based DER are analyzed to design the load shedding scheme for its survivability. Several case studies are illustrated to demonstrate the validity of the proposed load shedding method.