IEEE Power & Energy Magazine - January/February 2016 - 69

In ThIs arTIcle,an overvIew of The common
Information model (cIm) based data exchanges is provided,
along with how they are created and how they may be implemented within the enterprise or between utility entities. our
intent is to explain how the cIm can be used to generate
exchange packages and how those packages enable an integration framework. Using the cIm as a basis for all exchange
payloads ensures that the exchange content is clearly defined
in a standard way, and the data is interpreted the same across
different business domains.

Setting the Stage
Early History-Transmission Data Exchange

The initial cIm canonical model was created to allow
energy management system (ems)-to-ems import and
export of network models and to avoid the proprietary data
formats that complicated data exchange between ems systems. however, it was discovered almost immediately that
this model could also be used to exchange power system data
used in network analysis such as power flows, topology processing, and state estimation. These subsets of data became
known as profiles (see the "cIm Profiles for Data exchanges"
section for more information). The north american electric
reliability corporation was the first to suggest and define
requirements for a profile containing sufficient data to solve
a power flow. This resulted in the first profile known as the
common power system model (cPsm) profile, which would
be used by utilities and interconnections to generate more
accurate models and enhance grid reliability.
once the data content of the profile was defined, the
next step was to define the data format to be used within the
data file itself. The canonical cIm supports both detailed
node-breaker and bus-branch models for network analysis
applications. however, the cPsm profile was intended for
use in operational systems (ems) and hence supports
node-breaker models with detailed substations including breakers, disconnectors, measurements, and
equipment structures within substations. This is
different from bus-branch models intended
for power flow applications where all
substation detail has been replaced
by power flow buses.
network models have many
object types (e.g., breakers,
disconnectors, measurements, and voltage levels) and relationships among
them. representing these relationships in exchange documents can be made by
references (pointers) or

by inclusion of the referenced data at the place of the reference. Documents based on Xml schema (XsD) can include
referenced data by hierarchical nesting. hierarchical nesting
was the only mechanism to support references in XsD when
the cPsm was created. But the hierarchical nesting of references has drawbacks-the same data may be referenced multiple times, resulting in duplication or the data is not available
and can be referenced in another document. as a result, it was
decided to use a modified version of the resource Description
framework (rDf) Xml exchange format. This satisfies all
the industry requirements for the data exchange format and
avoids the drawbacks imposed by XsD. hence, the cImXml
exchange format described in the International electrotechnical commission (Iec) 61970-552 standard was created in
which all relationships are expressed as references.
The cPsm profile has since evolved into an extensive
standard set of profiles supporting many network analysis
applications as well as network-related data such as schematic diagrams. furthermore, its distribution counterpart,
the common Distribution Power system model (cDPsm),
has been developed as a set of profiles supporting distribution or unbalanced network analysis applications. This latter
also includes profiles that describe geographical locations
and physical equipment (assets) with their data sheet information and aspects of their life cycle management.

Recent Additions-Distribution
and Energy Market Data Exchange
while the base canonical cIm covers the needs for network
analysis studies, the utility industry wanted more, in particular, in the realm of distribution operations, where business processes were less dependent on the network analysis
model but needed to support data exchanges with various
enterprise systems. The canonical cIm started growing
beyond the network analysis view to support data exchanges
across the distribution domains including distribution operations (Dmss), outage management systems (omss), geographical information systems (GIss), work management
systems, customer management systems, meter data management systems, and various distribution network planning
applications. as the industry became more deregulated, the
base canonical cIm grew to support market management
systems as well as other external systems (e.g., enterprise
resource planning). when integrating the above systems, it is
important to specify not only what data is exchanged but also
how it is exchanged. This is typically described by expected
sequences of messages among interacting systems and relies
on some kind of enterprise messaging infrastructure with
required qualities of service (e.g., guaranteed delivery,
speed of delivery, traffic logging for audit trails, and security), especially important for the case of business to business exchanges. It is also usual practice to provide a standard

Digital Object Identifier 10.1109/MPE.2015.2485859
Date of publication: 30 December 2015

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