IEEE Electrification - December 2022 - 69

A microgrid is 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. It can connect
and disconnect from the grid to enable operation in
both grid-connected or island modes.
As a part of decentralized DER management solutions, the
MMC can be deployed in either a utility- or customerowned
microgrid.
ComEd deployed a pilot microgrid within the Bronzeville
community on the South Side of Chicago to test its potential
to enhance community resilience and grid flexibility.
The idea was sparked from the U.S. Department of Energy's
(DOE's) MMC project, which demonstrated the feasibility of
having two community microgrids clustered together via
coordinated control of their MMCs. Although it was only a
lab concept in the beginning, ComEd received funding from
its DOE's SHINES program via the Microgrid Integrated
Solar Storage Technology (MISST) project to deploy the
Bronzeville Community Microgrid (BCM) adjacent to the Illinois
Institute of Technology (IIT) Campus Microgrid (ICM).
As of today, the BCM has a 750-kW PV, 500-kW/2-MWh
BESS, and 4.8-MW controllable gas generation.
Sequence of Operation of the BCM
Figure 2 shows the one-line diagram of the BCM. It also
shows the detailed structure of a controller hardware-inthe-loop
simulation environment with a real-time digital
simulator (RTDS). This lab setup was developed as a part
of the DOE's MISST project.
When the BCM operates in grid-connected mode, the tie
switches (T1-T3) between feeder 1 and feeder 2 are in open
status, and both POIs (POI-1 and POI-2) are closed. In this
topology configuration, the BESS in the BCM can operate in
peak-shaving or renewable coordination mode, which both
focus on maintaining the power flow going through the POI
(POI-1, a G&W Viper) on feeder 1 within a preset limit. If the
grid source is lost due to severe weather events, the BCM
MMC shall open all switches within the microgrid, power
up customers sequentially on feeder 1 via controllable generation,
and then close tie switch (e.g., T2) to energize customers
on feeder 2. Solar and BESS may be selected to
participate in the power-restoration process depending on
weather (e.g., solar irradiance) and DER statuses (e.g., state
of charge). If the DERs in the BCM are not enough to power
up customers on both feeders 1 and 2, the BCM MMC will
send a request to the ICM MMC (if the ICM successfully
operates in microgrid mode at the same time) to secure
energy support by forming a microgrid cluster.
The bubble plot in Figure 3 illustrates the full picture of
the sequence of operation, including grid-connected,
islanded, system-restoration, and clustering modes.
Solar-BESS Coordination
One of the key deliverables in the DOE's SHINES MISST
project is the development and implementation of a
solar-BESS coordination (SBC) algorithm. The main objective
of the SBC is to improve the solar and storage scheduling
model in the BCM MMC. The proposed model
manages the following two unique characteristics of PV
units in a microgrid setting:
1) The PV unit outputs may vary rapidly.
2) The forecasted PV unit outputs fail to reflect the actual
PV unit output.
Although a microgrid has enough power and energy capacity
to manage both the rapid change and high forecasting
error (from a planning perspective), any effective scheduling
IEEE Electrification - December 2022

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