Comments on doing a CIM Project
jay.britton@areva-td.com
CIM Design Center
 A rule I learned about applying technology:
 Understand the design center of the technology.
 Use extreme caution if trying to apply the technology outside its design
center.
 CIM Design Center
 CIM standards aim to simplify integration of components and expand
options for supply of components by standardizing information
exchanges.

Reduce complexity with clear consistent semantic modeling across the enterprise.

Data sources: achieve a clear picture of data mastership in the enterprise.

Data consumers: make ‘data of record’ available on demand to qualified users.
 CIM employs a canonical data model (CDM) strategy for standardizing
interfaces in the power system operations and planning domain.
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What is a Canonical Data Model?
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CIM Design Center (cont’d)
 The CIM CDM is partitioned into sub-domains by IEC WGs.

These groups work hard to maintain a unified semantic model over the whole domain.
 The interfaces defined under CIM are organized into profiles.

A profile specifies the information structure of exchanged information by creating
contextual semantic models.
- Contextual semantic models are a subset of the CIM CDM. i.e. They inherit their structure
from the CIM CDM.
- Contextual semantic models could contain information not modeled in the CIM CDM.

• This is not current CIM practice for standard interfaces.
There is typically a family of related interfaces defined within a profile.

Products implement support for profiles.

Testing occurs against profiles.

CIM compliance is defined against profiles.
-
There is no such thing as just ‘CIM compliant’. You have to specify the profile.
 Do not expect CIM to make sense outside its design center.
 If its not needed in a CIM interface, don’t expect it to be in the
model.
 Don’t expect that CIM is a good database schema.
 Don’t expect CIM to make a good class design for your application.
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Overview of CIM Standards Methodology
Canonical
Data Model
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WG13 CIM Standards
CIM CDM
CDM Semantic Model
Equipment
Model
Measurement
Specification
State
Variables
Topology
Analog
Meas Set
Status
Meas Set
Contextual Semantic Model
Instance Data
Analog Set
scada
Status Set
state
estimation
State Var
Meas Spec
modeler
Equip model
topology
&
scheduling
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State Var
Topology
State Var
contingency
analysis
State Var
State Var
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CIM Evolution
 CIM is designed to achieve consistent, high quality models across a
large domain.
 This mission requires that CIM is able to change as new interfaces are
added.
 Typically it is not possible to preserve semantic quality if changes are
restricted to additions.
 At the global CDM level, change is embraced as long as it makes a
significant contribution to semantic quality.
 Stability may be addressed as appropriate at profile levels.
 Profiles are where the investment is made.
 Contextual model is derived from a version of the CIM CDM.
 Subsequent changes to CIM do not require that the contextual model be
updated.
 At the profile level, the participants in the profile can determine how often to
update their profile.
 About Versioning…
 CIM CDM and contextual models will change.
 Contextual models do not need to be updated simply because CIM CDM
changes.
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How to Cope with Versions
 An enterprise integration strategy based on CDM(s) is a good idea.
 Multiple CDMs are likely, but keep the number small.
 Extensions will be necessary when starting from core standards like CIM.
 An enterprise application of CIM will typically consist of information
exchanges based on more than one version of the CDM.
 Critical decision: CIM CDM may be adopted just as a starting point, or
the plan will be to keep current as CIM and contextual models evolve.
 Use of evolving Smart Grid standards will probably demand staying with
CIM.
 A successful evolution strategy requires discipline in implementation to
reduce the cost of subsequent updates.
 There will be lots of reasons raised as to why CIM should just be used as a
starting point.
 To enable evolution…
 Implementation must minimize direct connection between exchanged data
and internal data.
 i.e. Do not hardwire CIM to application internals – it makes changes too
costly.
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Transformations are Key
Compatible version exchange.
Producer App
Semantic Mdl
Transform
Spec
CIM Contextual
Model
Transform
Spec
Consumer App
Semantic Mdl
 Transform issues
 Clarity
 Simple, low cost
implementation
Producer
App
Instance Data
Transform
Exchanged
CIM Standard
Data
Consumer
App
Instance Data
Transform
 Maintainability
 Performance!
Incompatible version exchange.
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Producer App
Semantic Mdl
Transform
Spec
Producer
App
Instance Data
Transform
X
CIM
Version
CIM
ContextMdl Transform ContextMdl
Version x
Spec
Version y
Transform
Spec
Consumer App
Semantic Mdl
X-Y
Transform
Transform
Y
Consumer
App
Instance Data
CIM X
Data
CIM Y
Data
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 You may think that CIM is complex.
 From the standpoint of one information exchange
implementation, it is.
 If you compare life cycle of 100 exchanges, each
implemented in CIM, against other alternatives, CIM is
much simpler.
 CIM isn’t the easiest way to do anything – but it is the
easiest way to do everything.
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