Definitions

Term	Definition
distributed energy resource	Source of electric power that is not directly connected to a bulk power transmission system including both generators and energy storage technologies.
electric power system	Facilities to deliver electric power to one or more loads. The term is typically used as a generalization of a wide area grid such as a national power grid.
energy management system	A system of computer-aided tools used to monitor, control, and optimize the performance of the generation, transmission and distribution of electric power.
independent system operator	An organization that coordinates, controls, and monitors the operation of the electric power system, usually within a single US state, but sometimes encompassing multiple states.
islanding	The process by which a power system is split into two or more segments, each operating autonomously with its own energy resources such as occurs when a microgrid disconnects from the utility grid.
microgrid	A group of interconnected loads and distributed energy resources with clearly defined electrical boundaries that acts as a single controllable entity with respect to the grid that may connect and disconnect from the grid to enable it to operate in both grid-connected or island modes.
microgrid controller	A device that implements a microgrid control system.
microgrid control system	A system of control functions that permits a microgrid to manage distributed energy resources and loads to maintain acceptable frequency and voltage, operate autonomously and connect or disconnect from a utility grid, including its energy management system.
microgrid energy management system	The energy management system used by a microgrid.
nanogrid	A single domain of power—for voltage, capacity, reliability, administration, and price.
point of common coupling	The point where a microgrid attaches to a wider area grid such as a utility grid.
point of interconnect	See: point of common coupling.

Acronyms

Acronym	Definitions
DER	distributed energy resource
EMS	energy management system
EPS	electric power system
ISO	independent system operator or International Organization for Standardization
MEMS	microgrid energy management system
PCC	point of common coupling
POI	point of interconnect

Microgrid Definitions and Acronyms

Acronyms