IEEE Power & Energy Magazine - July/August 2017 - 82

the availability of renewable generation. The idea here was to
accomplish this objective through the right mix of renewables
and other generation and with the correct control schemes and
building design to allow maximum utilization of renewables
while still ensuring constant availability of service.
Based on these three motivations, economics-reliability, and desire for green/renewable energy-the Transactive Microgrid Technology Center, also known as South
Campus, was born.

Advanced Microgrid
Technology Framework
Microgrids come in different sizes and shapes with different
operational objectives. While one microgrid may place a lot
of emphasis on the quality of electricity it produces and how
infrequently it gets interrupted, another may focus on the cost
and accept a less-stringent power quality and lower levels of
electricity availability. Because of the difference in operational philosophy, the design and the technology requirements
for these two microgrids will be fundamentally different.
An advanced microgrid is-and must be-a combination of multiple types of technologies, equipment, controls,
and control schemes. Every microgrid will be different, with
key considerations given to factors such as size, operational
requirements, geographic location, and other elements.
Every microgrid design must use the best-in-breed technologies available to meet its specific objectives. Mindful of
the diverse technology requirements, the following detailed
architectural framework can be adapted to any microgrid for
its technology design. This framework builds on the fundamental concepts illustrated in the Electric Power Research
Institute's work.

Microgrid Technology Framework
As shown in Figure 1, the microgrid technology framework
consists of five layers of technology. Each layer performs a different function, operating on its own time horizon. An advanced

Layer 4: Energy Market, Grid, and Transactive Operations

microgrid orchestrates these layers so that each carries out its
own function while acting in concert with the others.
Layer 0: Physical Equipment

This most basic layer deals with equipment and load. It
includes resources such as microturbines, diesel generators,
wind generators, solar PV panels, storage systems, and the
point of coupling to the utility grid. It also includes loads,
both critical and noncritical loads and dispatchable loads,
which can be controlled if needed. Other devices such
as reclosers, switches, and circuit breakers also fall within
this category.
Layer 1: System Protection and Control

This layer deals with protection and control systems, which are
designed and deployed to deal with abnormal system conditions by disconnecting the faulted system. Examples of system
disturbances that need protection include faults on the system
or equipment. Protection and control systems include generator control, circuit overcurrent protection, other frequency and
voltage protection devices, and other types of devices. These
controls typically operate on a subsecond basis.
Layer 2: Automation and Control

This layer deals with process automation and control in
executing the processes necessary to facilitate system operations. Processes such as islanding, synchronization, and load
following need to be programmed for automated execution.
This layer normally uses programmable logic controllers or
other similar solutions, which are programmed to execute
the automated processes. This layer coordinates its operation
with layer 1.
Layer 3: Monitoring, Scheduling,
Optimization, and Dispatch

This layer provides monitoring, scheduling, optimization,
and dispatch of all microgrid resources, including purchases
from the utility to minimize the total cost of running the
microgrid. This layer considers the characteristics of all
resources, including solar, wind, and storage systems.
Layer 4: Energy Market, Grid, and Transactive Energy

Layer 3: Monitoring, Scheduling, Optimization, and Dispatch

Layer 2: Automation and Control

Layer 1: System Protection and Control

This layer provides solutions for interaction with the grid
as well as grid applications such as DR/DER management
for the provision of grid services, outage management, and
asset management. It also provides solutions for data analytics and reporting as well as solutions for interfacing with
electricity markets.

Cyber and Physical Security
Layer 0: Physical Equipment

figure 1. The broad layers of the microgrid technology
framework.
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ieee power & energy magazine

At each of these layers, the microgrid is protected with a
number of control systems. To ensure that the resiliency and
reliability objectives of microgrids are fulfilled, the cyber
and physical security vulnerabilities of a given microgrid
must be properly addressed.
july/august 2017

Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - July/August 2017