POWER August 2017 - 30

SMART GRID AWARD
Ameren's TAC Microgrid
Seamlessly Integrates
Distributed Energy Resources
Courtesy: S&C Electric Co.
The microgrid installation at the Ameren Illinois Technology Applications Center
(TAC) near the University of Illinois campus in Champaign-designed, engineered,
and constructed by S&C Electric Co. of Chicago-represents a state-of-the-art integration
of wind, solar, natural gas, and battery storage into a project that is POWER's
Smart Grid Award winner.
Kennedy Maize
"
Seamless. " That's the word that both
Ameren Illinois and S&C Electric use,
unbidden, to describe the microgrid
demonstration project they developed in
Champaign, Ill., near the University of Illinois
campus.
The microgrid that S&C, a 105-year-old
company that has long specialized in grid
and power engineering, built for Ameren is
the soul of the utility's Technology Applications
Center (TAC). The utility built the
TAC and its microgrid on property it owns
near the university, says Ameren in a press
release, to test and demonstrate " monitoring
and control methods for aggregating clean,
renewable energy sources-wind, solar and
natural gas-with advanced automation and
battery storage. "
Ameren says the microgrid, which went
into service earlier this year, " is one of the
few in the world that operate at utility-scale
voltages, between 4 kilovolts and 34.5 kilovolts,
with multiple levels of control. It is the
only known microgrid in the nation capable
of seamlessly transitioning the power source
for an entire distribution circuit from exclu30
sively
distributed generation sources to the
traditional grid. "
Mike Edmonds, S&C president of U.S.
business for the employee-owned, Chicagobased
company, which designed, engineered,
and installed the Ameren TAC microgrid, told
POWER that the microgrid is " on the [macro]
grid and off the grid seamlessly. " Other microgrid
implementations, he said, must stop to
adjust when they shift from grid connection to
island operation. On the TAC microgrid, users
" don't know the difference, " a very neat trick.
Switching from the big grid to the microgrid
requires changes in grounding, inertia, frequency
stability, and power quality.
Ron Pate, Ameren Illinois' senior vice
president for operations and technical services,
told POWER, " You're running on the
utility grid, and all of a sudden that's interrupted.
You've now got to look at load, economics,
make sure generation is available,
then balance the load and power quality. You
have all those balls juggling in the air at the
same time. "
Edmonds noted the challenges. When you
go off the grid, he said, " you've got all that
www.powermag.com
inertia " as coal stations go offline and other
resources are no longer available. The utility
has to provide the inertia from the loss of
the big generation and " keep the frequency
stable. " It involves tricky balancing of grid
harmonics to control the grid, along with important
preservation of power quality.
Reliability and Resiliency
Ameren's Pate said, " Our challenge was how
can we serve our customers seamlessly, so
the customer is not aware " of grid outages
and transitions between the conventional grid
and the microgrid.
The TAC microgrid, says S&C in a background
paper, " tackles this problem by demonstrating
the potential for widespread [distributed
energy resources (DERs)] integration within an
existing distribution network. The addition of
DERs combined with a sophisticated automation
distribution system and microgrid control
system can provide traditional utility providers
with improved reliability, resiliency, emissions,
savings, and security. "
The TAC microgrid can produce up to
1,415 kW of power, enough for about 190
POWER | August 2017
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POWER August 2017

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