While the need for interoperability between utility systems has always
been with us, what is it about today’s environment that makes it such a hot topic?
One factor is the move from centralized
to distributed generation. Another is the
aging of electric utility assets past their
Deregulation of the power industry, coupled with the smart grid as a
transformative movement, has also
significantly contributed to the overall complexity by expanding ( 1) the
number and variety of active participants; ( 2) the types of energy sources;
and ( 3) the kinds of active business
processes. As a result, power grid
operations have become dramatically
more dependent on complex computer-based analytically-intensive operating practices.
All of these changes have led to
the need for massive amounts of data
exchange, from systems/applications
supplied by many different vendors
within an enterprise (horizontal) to
distributed energy resources (DERs)
and microgrids and intelligent devices
at the edge of the grid (vertical). Add
to that the peer-to-peer and hierarchical information exchanges between
distribution and transmission system
operators and regional transmission
operators/independent system operators (RTO/ISOs).
One can only wonder if there is any
solution that can scale to deal with these
massive numbers of interconnections
between utility entities.
THE CANONICAL STRATEGY
Many utilities have recognized that if
they are going to successfully tackle this
level of operational complexity the first
step is to foster a data-driven culture.
A future-looking system framework
based on standards and a comprehensive enterprise semantic model can
act as a common language for data
exchange across the utility enterprise,
facilitating system interactions. This is
known as a canonical data model strategy for defining interfaces.
The International Electrotechnical
Commission (IEC) Common Information
Model (CIM) standards, specifically the
IEC 61968, 61970 and 62325 series,
were designed to provide such a solution
through a three-layer framework comprising ( 1) a UML-based information
model; ( 2) a set of business context-ori-ented interface profiles for defining
specific information exchange contents
based on a subset of the overall information model; and ( 3) message syntax and
implementation technologies for serializing data messages and files. Following
are sections that illustrate how these CIM
standards can be successfully applied in
practice to achieve interoperability.
Each series of CIM standards pro-
vides interoperability support using the
three-layer framework for a specific area
of the utility industry: IEC 61968 covers
the functions related to the support oper-
ations of the electric grid; IEC 61970 cov-
ers the functions related to the operation
and planning of the electric grid; and IEC
62325 covers the functions related to the
energy markets. The primary functions
discussed in this article surround the
operation and planning as well as the sup-
port operations of the electric grid.
The initial CIM canonical model was
created to allow data exchange and
interoperability between different energy
management systems (EMS). It was discovered, however, that this model could
be used to exchange many different kinds
of data for input into different network
analysis systems. Each of these exchanges,
once defined, became known as a profile
and the CIM became a mechanism to
exchange data to execute power flows,
topology processing and state estimation.
CIM FOR NETWORK ANALYSIS
Efficient, reliable operation and planning of today’s grid depends heavily
on computer-based network analysis.
Modern network analysis algorithms are
used in the planning, protection and
operations domains of today’s utilities
and they demand accurate models of the
grid. At present, there are too many manual steps in the network model maintenance process, requiring too much valuable engineering time. CIM standards for
power grid modeling can automate most
of these data processing steps, improving
both efficiency and accuracy.
A typical analytical model requires
datasets that originate from many different sources. As illustrated in Figure
BY MARGARET GOODRICH, JAY BRITTON, TERRY SAXTON AND PAT BROWN
Key to Integrated Grid Interoperability
The IEC CIM
Margaret Goodrich is president and principal consultant for Project Consultants LLC. Jay
Britton is principal consultant for Britton Consulting LLC. Pat Brown is principal technical
leader for ICT/Electric Power Research Institute.
Terry Saxton is vice president and co-founder
of Xtensible Solutions and co-chair for CIMug.