IEEE Power & Energy Magazine - July/August 2017 - 59

for all fault types with fault resistances ranging from 0
to 200 Ω (high impedance faults).
✔ Protection in the islanded mode of operation: Hierarchical microgrids will occur in this mode of operation. In this article, the substation 664 microgrid and,
at the lower level, the GridSTAR microgrid fall in to
this category. Adaptive protection with existing and/
or differential relays need to be judiciously adopted.
They need to be treated individually based on topology, generating sources, loads, relay architecture, and
other special considerations.

Dispatch: Grid Services
The ability of the microgrid controller to dispatch grid services will not be evaluated with dynamic simulations because
the time frames are not compatible. The ability to dispatch
DER assets will be simulated as part of the dispatch. The
ability of DERs to provide grid services will be demonstrated
as part of the live field tests.

Enhanced Resilience
The research revealed that no one single metric can assess
microgrid resilience. The best resource that confirmed this
assessment is the fascinating report published by RAND
Corporation in 2015 (http://www.rand.org/pubs/research_
reports/RR883.html), which was sponsored by the DOE.
The literature on measuring resilience contains examples of
metrics from each of these categories: inputs, capacities, capabilities, performance, and outcomes. When selecting
metrics for enhanced resilience, it is useful to understand
the availability and maturity of metrics that exist across
these categories.

Hierarchical Microgrid
Control System Architecture
Figure 6 shows the overview of the microgrid control architecture and the various components and their respective functions.

Microgrid Distribution Management System
The distribution management system (DMS) at TNY is implemented using GE's flagship e-terra distribution platform to
enable the DTE Energy Services distribution grid operators
team to monitor and control the entire distribution network
(three distribution substations and 55 feeders) efficiently and
reliably. The decision support system provides the control
room and field operating personnel with the monitoring and
control information of the electric distribution system.
The microgrid DMS collects the real-time measurements
and statuses of digital substations using the e-terra supervisory control and data acquisition (SCADA) and e-terra control
front-end processor. It is used to monitor all distribution network assets such as substations, distributed energy resources,
and generation units, thus providing real-time data on a single
console at the control center in an integrated manner.
july/august 2017

Microgrid Operation Management System
TNY has vast variety of assets in a very unique setting for
industrial/commercial microgrids with three distribution substations, over 55 feeders, more than 100 tenants with different
range and types of loads (medical, data center, heavy industrial,
pharmaceutical and life sciences, lifestyle, R&D, hospitality,
and small commercial customers), customer-owned behindthe-meter DERs, as well as community DERs such as natural
gas generators, an energy storage system, and a community
solar farm. This makes the microgrid operations at TNY
interesting as well as challenging, hence the GE microgrid
operations management system serves as the single pane of
glass view in to the entire TNY electrical operations including
electrical network operations via DMS/SCADA, smart meters
operation via AMI, customer operation via an engagement
portal, and asset operation via DER control systems.

Microgrid Data Interface Management
The microgrid operation system needs multiple data interface
support between TNY microgrid network operation center
and various field systems/devices within the microgrid, the
PECO distribution control room, and the PJM market control room. The GE microgrid data interface management
facilitates the integration of these sources of information. The
microgrid data interface management enables the integration
of data among the DMS, the SCADA system, OSI Soft PI
Historian, the L&G AMI system, and DERs using a single
platform. The platform has implemented a single data model
to monitor and manage asset across the domains such as the
electrical network, AMI communications, smart meter, customer information systems, and DERs. The platform enables
seamless integration of new data sources in to the microgrid
network operations center which is the backbone of the operation using the microgrid operations management.

Microgrid Automation Controller
The microgrid automation controller has been specifically designed for the optimization and control of grid-connected and off-grid, or islanded, microgrids which is based
on GE's substation automation hardware and microgrid
algorithms. The controller optimizes the cost of operation and energy in the presence of a mix of renewable and
nonrenewable generator sources. Figure 7 depicts the GE
microgrid controller together with supporting other grid/
substation automation components. The controller supports applications such as interlocking, on-demand triggers
and automatic feeder transfers that can be realized through
an embedded IEC 61131-3 programmable logic controller compliant user-based configurations. For the reliable
islanded and/or economic operations [during stressed (local/
bulk) grid conditions], it can also support on-demand load
shedding applications through simple point maps and
SCADA protocols.
This system enables the integration of all DER assets
at TNY such as energy storage systems, solar PV, diesel
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Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - July/August 2017