IEEE Power & Energy Magazine - January/February 2016 - 93

The relevant DER-related use cases
are being maintained as part of an IEC
use case repository.
1815 (DNP3) and IEEE 2030.5 (SEP 2), for integration with
existing communications infrastructure. Figure 9 illustrates
how the IEC 61850 information models can be used within a
communication architecture that uses DNP3 and SEP2.

Information Models for
Distributed Resources
The definition of the information models for distributed
resources is an ongoing effort. Both the IEC CIM and 61850
standards require ongoing work to incorporate relevant use
cases that define distributed resource integration functions.
In the United States, one of the groups leading this effort
is the Smart Inverter Working Group, initiated through a
joint agreement between the California Energy Commission and the California Public Utilities Commission. This
group has developed a list of autonomous functions (e.g.,
anti-islanding, volt/var control, disturbance ride through,
ramping, real and reactive power control, and frequency
response) and the use cases to define these functions. The
work builds on the efforts of an industry consortium that was
coordinated by the Electric Power Research Institute (EPRI)
and documented in an EPRI report (Common Functions for
Smart Inverters, Version 3, 3002002233) that became the
basis for the definitions in IEC 61850-90-7.
Certain basic functions, such as ride-through and voltvar control, can be implemented directly in smart inverters.
However, interfaces to external energy management systems
need to determine what values to supply for the functions
and when to use these functions. These external energy
management systems may be local or may be part of utility
DEMs (often called DERMS, specifically for the function
of controlling distributed resources). In turn, these energy
management systems have inputs from the power system,
from the DER systems, DER owner-operators, and market
signals. These use cases and the IEC library of use cases
provide the basis for ongoing definition of information models and information exchange requirements in the CIM and
in IEC 61850 standards.

Next Steps
Information model standards (both IEC 61850 and the CIM)
will play a critical role in the true integration of distributed
resources with the operation of the grid. Implementation of
a standards-based information architecture and information
models will unleash innovation and allow the full value of the
integrated grid to be realized. Now that we have preliminary
definitions for many of these distributed resource functions
january/february 2016

and associated information exchanges, we are actively implementing these information exchanges in smart inverters and
distributed energy resource management systems. These are
being tested in labs like the NREL Energy Systems Integration Facility and Fraunhofer in Germany, as well as in pioneering field installations, such as being demonstrated at Salt
River Project in Arizona and the evolvDSO demonstrations
in Europe. Results of these lab and field trials will provide
the validation of these models so that widespread deployment
of these resources can be integrated with common tools and
systems. The relevant DER-related use cases are being maintained as part of an IEC use case repository. These use cases
serve as a reference, and will allow CIM and 61850 model
improvement for distributed resources.

For Further Reading
EPRI. (2015, Feb.). The integrated grid: A benefit-cost framework. EPRI Publication 3002004878. [Online]. Available:
http://www.epri.com/abstracts/Pages/ProductAbstract.aspx?Pr
oductId=000000003002004878
NIST. (2014, Sep.). NIST Framework and roadmap for
smart grid interoperability standards, release 3.0. NIST Special
Publication 1108r3. [Online]. Available: http://www.nist.gov/
smartgrid/upload/NIST-SP-1108r3.pdf
CEN-CENELEC-ETSI Smart Grid Coordination Group.
(2012, Nov.). Smart Grid reference architecture. [Online]. Available: http://ec.europa.eu/energy/sites/ener/files/documents/
xpert_group1_reference_architecture.pdf
Intelligrid Common Information Model Primer: Second
Edition. EPRI Report 3002001040, Oct. 2013.
evolvDSO. (2014, Nov.) Development of methodologies and
tools for new and evolving DSO roles for efficient DRES integration in distribution networks. Deliverable D2.2. [Online].
Available:
http://www.evolvdso.eu/getattachment/cd99e181f0b5-4d38-9663-e001377a2468/Deliverable-D2-2.aspx

Biographies
Mark McGranaghan is with the Electric Power Research
Institute (EPRI), Knoxville, Tennessee.
Doug Houseman is with Enernex Corporation, Detroit,
Michigan.
Laurent Schmitt is with Alstom Smart Grids Solutions,
Paris, France.
Frances Cleveland is with Xanthus Consulting International, Boulder Creek, California.
Eric Lambert is with EDF, Paris, France.
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http://www.epri.com/abstracts/Pages/ProductAbstract.aspx?Pr http://www.nist.gov/ http://ec.europa.eu/energy/sites/ener/files/ http://www.evolvdso.eu/getattachment/cd99e181

Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - January/February 2016