This PDF file has been prepared by TC 57 experts and is made
available to assist the users of the IEC 61850-7 series.
Please note:
There was no IEC vote on these files, and IEC Central Office does
therefore not take any responsibility as to their contents.
Adobe Acrobat 6.0 is required to navigate through this file.
Any comments on these files are to be communicated to the following
address:
Karlheinz Schwarz
(schwarz@scc-online.de)
IEC 61850 - Communication networks and systems in substations
Informative tutorial on the object models
NOTE 1 These pdf files (html pages) are intended to provide a hypertext version of an excerpt of the main
concepts and definitions of Parts IEC 61850-7-4, IEC 61850-7-3, and IEC 61850-7-2.
NOTE 2 The content of these files is informative only. They do in no way replace the normative definitions
contained in the above referenced documents.
There are the following pages to browse and study the object models:
1. Modeling approach of logical nodes (one page - pdf)
2. IEC 61850-7-2 Overview of ACSI models
3. Logical nodes of 61850-7-4
4. Common data classes in a single window
The xml files containg the models are (not available in the pdf format):
- Logical Nodes from IEC 61850-7-4:2003 LN.xml
- DATA Semantics from IEC 61850-7-4:2003 Data-Sematic.xml
- DATA-Attributes from IEC 61850-7-3:2003 CDC.xml
- DATA-Attribute Semantics from IEC 61850-7-3:2003 DA-Semantic.xml
- Common Data Attributes from IEC 61850-7-3:2003 CDA.xml
These xml files can be used to produce any other presentation. They should not be used as normative
xml documents.
Parts of the standard
● IEC 61850-1, Part 1: Introduction and overview
● IEC 61850-2, Part 2: Glossary
● IEC 61850-3, Part 3: General requirements
● IEC 61850-4, Part 4: System and project management
● IEC 61850-5, Part 5: Communication requirements for functions and devices models
● IEC 61850-6, Part 6: Configuration description language for communication in electrical
substations related to IEDs
● IEC 61850-7-1, Part 7-1: Basic communication structure for substation and feeder equipment -
Principles and models
● IEC 61850-7-2, Part 7-2: Basic communication structure for substation and feeder equipment -
Abstract communication service interface (ACSI)
● IEC 61850-7-3, Part 7-3: Basic communication structure for substation and feeder equipment -
Common data classes
● IEC 61850-7-4, Part 7-4: Basic communication structure for substation and feeder equipment -
Compatible logical node classes and data classes
● IEC 61850-8-1, Part 8-1: Specific communication service mapping (SCSM) - Mappings to MMS
(ISO/IEC 9506-1 and ISO/IEC 9506-2) and to ISO/IEC 8802-3
● IEC 61850-9-1, Part 9-1: Specific communication service mapping (SCSM) - Sampled values
over serial unidirectional multidrop point to point link
● IEC 61850-9-2, Part 9-2: Specific communication service mapping (SCSM) - Sampled values
over ISO/IEC 8802-3
● IEC 61850-10, Part 10: Conformance testing
The web pages and the corresponding xml files have been created by
Karlheinz Schwarz, SCC. (schwarz@scc-online.de)
SCC does not take any responsibility as to the content of the files contained in the ZIP file
"IEC61850_HTML.zip" (html, xml and jpg) or the "browsable" pdf file and linked on this page
respectively.
Karlheinz Schwarz, based in Karlsruhe, Germany, is a consultant for the power systems control
industry. He is involved in several Working Groups within IEC TC 57, TC 65, and TC 88. He is a well-
known authority on the standardization and application of advanced information and communication
technologies.
© IEC 2004
Version 1.1 2004-03-22
© SCC Draft 0-2 2004-01-03
What is a Logical Node?
By Karlheinz Schwarz, SCC, schwarz@scc-online.de
Motivation
The standard IEC 61850 „Communication networks and systems in substations“ and the
coming standard IEC 61400-25 „Communications for monitoring and control of wind power
plants“ use the concept of Logical Nodes (LN) as a key element to define the information of
a device to be communicated. This paper introduces the concept of LNs.
Modeling
oncept
IEC 61850
models substation
equipment and func-
tions (focus is on
protection)
IEC 61400-25
models components
of wind power plants
like rotor, generator,
gear box, nacelle etc.
(focus is on SCADA)
A key issue are the LNs representing functions or equipment used in power systems. Each
LN provides a list of well organized and named information
. The LN “XCBR5” represents
the “circuit breaker” number 5 with the data “Pos” (Position) and “Mode”. Services defined
in IEC 61850-7-2 allow the exchange of this information.
Mapping
...
(Virtual World)
LN
LNLN
LN
Pos
SCSM
IEC 61850-8-1
TCP/IP
Network
MMS
IEC 61850-7-2
Services
logical device (Bay)
Mode
XCBR5
IEC 61850-7-4 logical
node (circuit breaker)
IEC 61850-7-4
data (Position)
virtualisation
Real
devices in a
substation
IEC 61850-6
configuration file, XML
The substation configuration language in part 6 supports the engineering process.
Example LN
“MMXU”
IEC 61850-7-4
defines some
90 LNs
500 Data
100 Attributes
10 Service models
IEC 61400-25
adds some
10 LNs
200 Data
100 Attributes
The measurement LN “MMXU” represents power, voltages, currents, and impedances in a
three-phase system. The values can be communicated by various services
TotW
TotVAr
TotVA
TotPF
Hz
PPV
PhV
A
W
VAr
VA
PF
Z
Total Active Power (Total P)
Total Reactive Power (Total Q)
Total Apparent Power (Total S)
Average Power factor (Total PF)
Frequency
Phase to phase voltages (VL1VL2, …)
Phase to ground voltages (VL1ER, …)
Phase currents (IL1, IL2, IL3)
Phase active power (P)
Phase reactive power (Q)
Phase apparent power (S)
Phase power factor
Phase Impedance
Logical Node „MMXU“
current / voltage samples from instrument
transformers represented by LN “PhsBTCTR” for
current transformer of phase B (e.g. by sampled
value exchange services of IEC 61850-7-2 SV)
LN PhsBTCTR
Amp
LN PhsBTCTR
Amp
LN PhsBTVTR
Vol
LN PhsBTVTR
Vol
IEC 61850-7-2
Log
Log
Read
Read
Report
Report
Configure
Configure
Retrieve
Model
Retrieve
Model
QueryLog
QueryLog
phsA.cVal
phsB.cVal
phsC.cVal
deadbanded value
angle
SV
SV
SV
SV
IEC 61850-7-2
RCB
RCB
The “MMXU” LN offers hundreds of values: measured (process) values, configuration val-
ues, description, and substitution values. These values can be communicated by various
services like read (polling), notification (publish/subscribe), logging and query.
ACSI overview and basic concepts
General
The models of the ACSI provide
● the specification of a basic model for the definition of the substation-specific information models contained
in IEC 61850-7-3 (common DATA classes) and IEC 61850-7-4 (compatible LOGICAL-NODE classes and
compatible DATA classes) and
● the specification of information exchange service models.
The information models and information exchange services are interwoven. From a descriptive point of view, the
two aspects are separated to some degree (see the excerpt shown in Figure 1). The common models (for
example, LOGICAL-NODE and DATA classes including their services) are applied in IEC 61850-7-3 and IEC
61850-7-4 to define many specialized information models - the substation automation models.
Figure 1 - Excerpt of conceptual model
Other service models required for substation automation systems (for example, DATA-SET and reporting provide
specific information exchange services) are also defined in this part of the standard; these models are linked to
LOGICAL-NODEs and DATA. The information exchange services are completely defined in the ACSI. The
information models defined in IEC 61850-7-4 reference the services defined in the various models of the ACSI.
Overview of basic information models
The conceptual models to build the domain-specific information models are:
● SERVER - represents the external visible behaviour of a device. All other ACSI models are part of the
server.
NOTE 1 A server has two roles: to communicate with a client (most service models in IEC 61850 provide
communication with client devices) and to send information to peer devices (for example, for sampled
values).
● LOGICAL-DEVICE (LD) - contains the information produced and consumed by a group of domain-specific
application functions; functions are defined as LOGICAL-NODEs.
● LOGICAL-NODE (LN) - contains the information produced and consumed by a domain-specific application
function, for example, overvoltage protection or circuit-breaker.
● DATA - provide means to specify typed information, for example, position of a switch with quality
information and timestamp, contained in LOGICAL-NODEs.