IEC TS 61970-555:2016

IEC TS 61970-555 ®
Edition 1.0 2016-09
TECHNICAL
SPECIFICATION
colour
inside
Energy management system application program interface (EMS-API) –
Part 555: CIM based efficient model exchange format (CIM/E)

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IEC TS 61970-555 ®
Edition 1.0 2016-09
TECHNICAL
SPECIFICATION
colour
inside
Energy management system application program interface (EMS-API) –

Part 555: CIM based efficient model exchange format (CIM/E)

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.200 ISBN 978-2-8322-3653-6

– 2 – IEC TS 61970-555:2016 © IEC 2016
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references. 7
3 Terms and definitions . 7
4 Use case . 8
4.1 General . 8
4.2 Real-time sharing on CIM model . 8
4.3 Online Dynamic Stability Analysis (DSA) . 10
5 Symbol definitions . 10
6 Structure Specification . 11
6.1 General . 11
6.2 Basic structure . 11
6.3 Comment . 12
6.4 System declaration . 12
6.5 Root element . 13
6.6 Model header . 13
6.7 Block structure . 13
6.8 Data block. 14
6.8.1 General . 14
6.8.2 Data block header . 14
6.8.3 Data block contents . 14
6.8.4 Blank separator . 14
6.8.5 Assignment connector . 14
6.8.6 Object pointer . 15
6.8.7 Compound . 15
7 Incremental model . 16
7.1 General . 16
7.2 Structure of incremental model . 16
7.3 Data block of incremental model . 17
8 CIM/E Schema . 18
8.1 General . 18
8.2 Schema structure . 18
8.3 Class description . 19
8.4 Enumeration block . 19
8.5 Compound type . 20
9 Usage . 21
Annex A (informative) The example of CIM/E . 22
Annex B (informative) Mapping CIM/E to CIM/XML . 23
Bibliography . 24

Figure 1 – Interconnection power grid . 9
Figure 2 – CIM model exchange and merge . 9
Figure 3 – Online dynamic stability analysis . 10

Figure 4 – Model exchange mechanism based on CIM/E . 11
Figure 5 – Transverse-table structure . 12
Figure 6 – Vertical-table structure . 12
Figure 7 – Usage example of object pointer . 15
Figure 8 – Usage example of compound type . 15
Figure 9 – The 1st form of incremental model description format . 16
Figure 10 – The 2nd form of incremental model description format . 17
Figure 11 – CIM/E schema description . 18
Figure 12 – The multiplicity in class definition . 19
Figure 13 – The example of enumeration definition . 20
Figure 14 – Example of compound attribute definition . 20
Figure A.1 – An example of CIM/E . 22

Table 1 – Symbol definitions . 10
Table B.1 – Mapping CIM/E to CIM/XML . 23

– 4 – IEC TS 61970-555:2016 © IEC 2016
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ENERGY MANAGEMENT SYSTEM APPLICATION
PROGRAM INTERFACE (EMS-API) –
Part 555: CIM based efficient model exchange format (CIM/E)

FOREWORD
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The main task of IEC technical committees is to prepare International Standards. In exceptional
circumstances, a technical committee may propose the publication of a technical specification
when
• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
Technical specifications are subject to review within three years of publication to decide whether
they can be transformed into International Standards.
IEC TS 61970-555, which is a technical specification, has been prepared by IEC technical
committee 57: Power systems management and associated information exchange.

The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
57/1730/DTS 57/1769/RVC
Full information on the voting for the approval of this technical specification can be found in the
report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 61970 series, published under the general title Energy management
system application program interface (EMS-API), can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific publication. At this date, the publication will be
• transformed into an International standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

– 6 – IEC TS 61970-555:2016 © IEC 2016
INTRODUCTION
This part of IEC 61970, which is a technical specification, describes ‘CIM-E’, an alternative to
IEC 61970-552 (CIM/XML) for serializing CIM data exchanges, which is in use in China. It is a
general method of serialization that could be used with any defined exchange, but it was
developed specifically as an alternative to IEC 61970-552 for exchanging power system network
models and solutions, which are defined in IEC 61970-452 and IEC 61970-456. Following is an
explanation as to why the IEC has formally documented this method in addition to
IEC 61970-552.
When the IEC first developed its standard for exchanging power system models, the primary
model exchange specification, IEC 61970-452, described exchange of a complete model. The
companion standard, IEC 61970-552, specified how to serialize model data for exchange, and
also described how to serialize ‘incremental updates’ of a model in which only changed parts are
exchanged. This latter feature was included because complete models could be very large and
require significant processing time, but in most real business situations, model transfers are
updates of previous exchanges in which only small parts of the models have changed.
Unfortunately, while the IEC understood the potential value of incremental processing, no ‘use
cases’ were produced to document the situations in which full or incremental processing would
be recommended.
At the time that the IEC was producing these documents, China was following the development
of CIM standards and planning to use them. The situations in which they wanted to use CIM
model exchange demanded high performance. The solution they chose was CIM-E, a more
compact version of serialization than CIM/XML, which their applications could process quickly.
As time passed, the IEC expanded its set of exchanges to include solved cases and continued to
envision incremental updates as the approach for optimizing performance. China began to
participate actively in WG 13 meetings, and also continued to enhance the CIM-E serialization
method, which is a national standard now in China.
In 2011, China proposed that IEC adopt CIM-E as a standard. The IEC concluded that a CIM-E
specification was appropriate. China represents a significant part of the world’s electricity
infrastructure. It is using CIM. The IEC therefore felt that an IEC specification for CIM-E would be
useful, provided that it simply presented a specification for meeting a requirement for CIM-E
exchange and did not endorse CIM-E as the recommended method for achieving high
performance.
The IEC 61970 series defines an Application Program Interface (API) for an Energy
Management System (EMS).
IEC 61970-301 specifies a Common Information Model (CIM): a logical view of the physical
aspects of electric utility operations. The CIM is described using the Unified Modeling Language
(UML), a language used to specify, visualize, and document systems in an object-oriented
manner. UML is an analysis and design language; it is not a programming language. For
software programs to use the CIM it needs to be transformed into a schema form that supports
a programmable interface.
This part of IEC 61970 describes the translation of the CIM in UML form into a machine readable
format as expressed in CIM based Efficient Model Exchange Format(CIM/E) representation of
that schema using the CIM/E Schema.
This part of IEC 61970 specifies how the CIM/E schema is used to support power system models
or particular application data models exchange requirements, especially for real-time or online
applications. Similar to CIM/XML, CIM/E is an efficient serialization format to describe CIM
objects. The power system model described by CIM/E or by CIM/XML can be converted
bi-directionally with consistent result.

ENERGY MANAGEMENT SYSTEM APPLICATION
PROGRAM INTERFACE (EMS-API) –
Part 555: CIM based efficient model exchange format (CIM/E)

1 Scope
This part of IEC 61970, which is a technical specification, specifies a Component Interface
Specification (CIS) for Energy Management Systems Application Program Interfaces. This part
specifies the format and rules for exchanging modelling information based upon the CIM. It uses
the CIM/E Schema as the meta-model framework for constructing CIM/E documents of power
system modelling information. The style of these documents is called CIM/E format. CIM/E is
suitable for use in online model exchange of power system applications.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 61970-452, Energy management system application program interface (EMS-API) – Part
452: CIM model exchange specification
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
Application Program Interface
API
the set of public functions provided by an executable application component for use by other
executable application components
3.2
Common Information Model
CIM
abstract model that represents all the major objects in an electric utility enterprise typically
contained in an EMS information model
Note 1 to entry: By providing a standard way of representing power system resources as object classes and
attributes, along with their relationships, the CIM facilitates the integration of EMS applications developed
independently by different vendors. It provides a common information presentation between EMS systems developed
independently, or between an EMS system and other systems concerned with different aspects of power system
operations, such as generation or distribution management.

– 8 – IEC TS 61970-555:2016 © IEC 2016
3.3
CIM/E Schema
schema specification expressed by using CIM/E format to describe classes and their attributes
and associations
3.4
Energy Management System
EMS
Computer system comprising a software platform providing basic support services and a set of
applications providing the functionality needed for the effective operation of electrical
generation and transmission facilities so as to ensure adequate security of energy supply at
minimum cost
3.5
profile
schema that defines the structure and semantics of a model that may be exchanged
Note 1 to entry: A Profile is a restricted subset of the more general CIM.
3.6
Unified Modelling Language
UML
object-oriented modelling language and methodology for specifying, visualizing, constructing,
and documenting the artefacts of a system-intensive process
3.7
Uniform Resource Identifier
URI
object-oriented modelling language and methodology for specifying, visualizing, constructing,
and documenting the artefacts of a system-intensive process
4 Use case
4.1 General
With the rapid development of the power industry and renewable energy in the world, a large
scale of random intermittent wind power and photovoltaic power are integrated to grids and
system operators are faced with great challenges. There is a pressing need for the cooperation
of multiple control centres to know the real-time situation of the adjacent system and all the
power grids. Therefore, the real-time model and graphics of power systems should be shared
among all related control centres. Both the ‘ENTSO-E Real-time Awareness and Alarm System’
project in Europe and the ‘Smart Grid Dispatching Platform’ project in China attempt to achieve
this goal under urgent requirements.
4.2 Real-time sharing on CIM model
Consider an interconnection power grid with two Control Centres, A and B, as shown in Figure 1.
Each control centre has an EMS from different vendors. Although A has no direct responsibility
for parts of the grid supervised by B, B still has an influence on A’s grid. A is, therefore, obliged
to maintain a model of these additional parts in at least enough detail to gauge their effect on its
own part of the grid.
A
B
IEC
Figure 1 – Interconnection power grid
Each control center maintains an official, detailed model of its own territory, and regularly makes
all updates available to its neighbors by CIM/E. Each control center receives its neighbors’
models and merges them together into a full detailed interconnection model, as shown in
Figure 2.
CIM/E
Model Exchange
Interface
2 3
Model A Model A
Model B Model B
Boundary Model
Exchange
Model Authority Model Authority
EMS A
EMS B
Model Format
Model Format
Control center A Control center B

IEC
Figure 2 – CIM model exchange and merge
This diagram shows the interaction between these two control centers, A and B. All actions are
the same at each control center. Therefore, we can simply follow the steps as A makes a
change:
a) A makes a change in its system model using its local EMS modeller.
b) A’s model authority releases either its full model or the increment to CIM/E file and sends it
to B.
c) B receives and verifies the model.
d) B extracts A’s territory from the model according to the boundary and merges them together
into a detailed interconnection model (B reduces A if necessary).
e) B imports the resulting model of A into its Model Authority and its EMS model.

– 10 – IEC TS 61970-555:2016 © IEC 2016
4.3 Online Dynamic Stability Analysis (DSA)
The CIM/E solution has been used for an on-line Dynamic Stable Analysis (DSA) project in
China, as shown in Figure 3. The DSA is activated by real-time event or runs every 15 minutes.
It is also applied on smart grid dispatching platform pilot projects, which is a new generation
platform for EMS, DSA, WAMS and MMS. These projects have been put into operation at many
control centers and the main objective of sharing real-time models for the whole power system
among multiple control centres has been achieved.
IEC
Figure 3 – Online dynamic stability analysis
5 Symbol definitions
The symbols used in this standard are specified in Table 1.
Table 1 – Symbol definitions
Number Symbol Definition Note
1 <> class start tag Compliant with XML
2 class end tag Compliant with XML
3 system declaration Compliant with XML
4 <@> Data block header leading for transverse-table Compliant with XML
5 <@#> Data block header leading for vertical-table Compliant with XML
6 <#> data line start tag Compliant with XML
7 // comment start tag Non-XML
8 : namespace connector Compliant with XML
9 :: class and instance entity connector Non-XML
10 = assignment connector Compliant with XML
11 . connector for names Compliant with XML
12 * pointer leading Non-XML
13 blank Field separator, may be one or more spaces or tab characters Compliant with XML
14 ’ single quotation for string Compliant with XML
15 NULL empty indicator Compliant with XML
16 - Unchanged or non-value indicator Non-XML
17 , comma separator Compliant with XML

6 Structure Specification
6.1 General
A power system model can be described as a CIM/E data file according to the CIM/E schema,
specified in Figure 1. The CIM/E schema is a RDF schema specification for CIM/E document.
The resulting CIM/E data file, which is used as model exchange document, can be parsed and
imported into an external system. The model exchange mechanism based on CIM/E is shown in
Figure 4.
Proprietary
Power System
Data
CIM
in UML
CIM/E Importer/
Schema Exporter
specify
RDF
Schema
Power
reference
System Data
as
CIM/E
IEC
Figure 4 – Model exchange mechanism based on CIM/E
CIM/E is in plain text format. The first two or three characters of each line in a CIM/E format file
are used to indicate the meaning of the line for efficient text processing.CIM/E is case-sensitive.
6.2 Basic structure
CIM/E file consists of system declaration, one model header, one or more blocks. There are
three kinds of blocks: Data Block, Schema Block and Enumeration Block. The comment line
starts with ‘//’ indicating a comment and could appear anywhere in the file. The CIM/E file has
two basic table structures; one is transverse-table structure and the other is vertical-table
structure. They are specified in Figure 5 and Figure 6 respectively.

– 12 – IEC TS 61970-555:2016 © IEC 2016
System declaration

Root elem
...