This document covers intentional islands in electric power systems (EPSs) that contain distributed
resources (DRs). The term DR island systems, sometimes referred to as microgrids, is used for these
intentional islands. DR island systems are EPSs that:
(1) have DR and load.
(2) have the ability to disconnect from and parallel with the area EPS.
(3) include the local EPS and may include portions of the area EPS.
(4) are intentionally planned. DR island systems can be either local EPS islands or area EPS.
islands. This document addresses issues associated with DR island systems on both local and area islanded
EPSs. It provides an introduction and overview and addresses engineering concerns related to DR island
systems.