IEEE Power & Energy Magazine - July/August 2017 - 79

In this article, we offer a well-proven approach to capture
stakeholder requirements for adequately integrating microgrid
platforms into our utility grids.

Weather
Information

Real-Time
Information

Production
Forecast
Load
Forecasting
Optimization
Forecast
Historical
Data

For Further Reading
Lower Layer

figure 10. Tertiary control inputs and output.

portfolio optimization. Figure 8 illustrates the distributed
control architecture for secondary control.

Tertiary Control
Model-based control functions are best handled at the highest
control level: tertiary. These advanced control functions include
economic dispatch, optimal power management, and power
scheduling and planning. Stakeholder requirements addressed
by this technical approach include distributed load and generator utilization optimization, generation cost optimization, and
CO2 emission control. Figure 9 depicts interoperability among
all control layers as well as their typical functions.
To realize many of these advanced control functions, modelbased optimization algorithms rely on generator and load
forecasts. Predicted energy production from renewable DERs
and predicted load profiles are key factors. For economic dispatch, for example, tertiary control software considers current
and future energy prices for each resource in the microgrid.
An interface with the regional market system operator (i.e.,
Midcontinent Independent System Operator and Pennsylvania-New Jersey-Maryland Interconnection) would be required
for pricing energy sourced from the utility's network. Once
the optimization is performed, the control framework relies
on the secondary control layer to update device statuses and
issue dispatch commands. Figure 10 illustrates how forecasting and optimization functions relate to tertiary control inputs
such as weather and pricing information.

Conclusions
As more DERs continue to be integrated into the utility's
network, much deeper thought should be given to their
overall interoperability and management. Using a systems
engineering approach will insure the system's safe, reliable and optimal operation. In this article, we offer a welljuly/august 2017

proven approach to capture stakeholder requirements for
adequately integrating microgrid platforms into our utility
grids. A focus on control design is given since it is arguably
the most complex subsystem in a microgrid platform. We
acknowledge that the industry has a long way to go before
taking full advantage of all methods available in the field of
systems engineering.

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Biographies
Alex Rojas is with Ameren Services, St. Louis, Missouri.
Tamer Rousan is with Ameren Illinois, Champaign, Illinois.
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ieee power & energy magazine

https://ocw.mit.edu/courses/engineering-systems-division/ https://ocw.mit.edu/courses/ https://www.arxiv.org/pdf/1504.06784.pdf http://smartgrid.ieee.org/march-2012/527-microgrids https://www.navigantresearch.com/research/

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