IEC 61850-9-2:2004

INTERNATIONAL IEC
STANDARD 61850-9-2
First edition
2004-04
Communication networks and systems
in substations –
Part 9-2:
Specific Communication Service Mapping (SCSM) –
Sampled values over ISO/IEC 8802-3

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INTERNATIONAL IEC
STANDARD 61850-9-2
First edition
2004-04
Communication networks and systems
in substations –
Part 9-2:
Specific Communication Service Mapping (SCSM) –
Sampled values over ISO/IEC 8802-3
 IEC 2004  Copyright - all rights reserved
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mechanical, including photocopying and microfilm, without permission in writing from the publisher.
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– 2 – 61850-9-2  IEC:2004(E)
CONTENTS
FOREWORD.4
INTRODUCTION.6

1 Scope.7
2 Normative references.7
3 Terms and definitions .9
4 Abbreviations.9
5 Communication stack.10
5.1 Overview of the protocol usage .10
5.2 Client/server services and communication profiles .11
5.3 SV service and communication profile .13
5.4 Restrictions.15
6 Mapping of IEC 61850-7-2 and IEC 61850-7-3 Data Attributes.16
7 Mapping of IEC 61850-7-2 classes and services .16
7.1 Classes of SV data sets .16
7.2 Definition of SV data sets .16
8 Mapping of the model for the transmission of sampled values .16
8.1 Overview.16
8.2 Mapping of the multicast sampled value control block class and services .16
8.3 Mapping of the unicast sampled value control block class and services .17
8.4 Mapping of the update of the sampled value buffer.19
8.5 Additional definitions for the transmission of sampled values.19
8.6 Definitions for basic data types .21
9 Conformance.21
9.1 Notation.21
9.2 PICS .21
10 Substation Configuration language (SCL).23

Annex A (informative) ISO/IEC 8802-3 frame format and ASN.1 basic encoding rules.24
Annex B (informative) Process bus architectures .27
Annex C (informative) Multicast address selection .28

Figure 1 – OSI reference model and profiles.10
Figure 2 – Structure of the tag header .14
Figure 3 – Concatenation of several ASDU's into one frame .19
Figure A. 1 – ISO/IEC 8802-3 frame format .24
Figure A.2 – Basic encoding rules format .25
Figure A.3 – Format of the tag octets .25
Figure A.4 – Example for an ASN.1 coded APDU frame structure.26
Figure B.1 – Alternative process bus architectures .27

61850-9-2  IEC:2004(E) – 3 –
Table 1 – Service requiring client/server communication profile .11
Table 2 – Service and protocols for client/server communication A-Profile .12
Table 3 – Service and Protocols for Peer TCP/IP T-Profile.12
Table 4 – Service requiring SV communication profile .13
Table 5 – Service and protocols for SV communication A-Profile .13
Table 6 – SV T-Profile .13
Table 7 – Default Virtual LAN IDs and priorities .14
Table 8 – Assigned Ethertype values .15
Table 9 – MMS TypeDescription definition for MSVCB MMS structure.17
Table 10 – Mapping of multicast sampled value services .17
Table 11 – MMS TypeDescription definition for USVCB MMS Structure.18
Table 12 – Mapping of unicast sampled value services .18
Table 13 – Encoding for the transmission of the sampled value buffer .20
Table 14 – Encoding for the basic data types.21
Table 15 – PICS for A-Profile support.22
Table 16 – PICS for T-Profile support.22
Table 17 – SV conformance statement.22
Table 18 – Definitions for SV SCL.23

– 4 – 61850-9-2  IEC:2004(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
COMMUNICATION NETWORKS AND SYSTEMS IN SUBSTATIONS –

Part 9-2: Specific Communication Service Mapping (SCSM) –
Sampled values over ISO/IEC 8802-3

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61850-9-2 has been prepared by IEC technical committee 57:
Power systems management and associated information exchange.
The text of this standard is based on the following documents:
FDIS Report on voting
57/690/FDIS 57/709/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

61850-9-2  IEC:2004(E) – 5 –
IEC 61850 consists of the following parts, under the general title Communication networks
and systems in substations:
Part 1: Introduction and overview
Part 2: Glossary
Part 3: General requirements
Part 4: System and project management

Part 5: Communication requirements for functions and device models
Part 6: Configuration description language for communication in electrical substations
related to IEDs
Part 7-1: Basic communication structure for substation and feeder equipment – Principles and
models
Part 7-2: Basic communication structure for substation and feeder equipment – Abstract

communication service interface (ACSI)
Part 7-3: Basic communication structure for substation and feeder equipment – Common data
classes
Part 7-4: Basic communication structure for substation and feeder equipment – Compatible
logical node classes and data classes
Part 8-1: Specific Communication Service Mapping (SCSM) – Mappings to MMS (ISO 9506-1
and ISO 9506-2) and to ISO/IEC 8802-3
Part 9-1: Specific Communication Service Mapping (SCSM) – Sampled values over serial
unidirectional multidrop point to point link
Part 9-2: Specific Communication Service Mapping (SCSM) – Sampled values over
ISO/IEC 8802-3
Part 10: Conformance testing
The committee has decided that the contents of this publication will remain unchanged until
2005. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this document may be issued at a later date.

———————
Under consideration.
– 6 – 61850-9-2  IEC:2004(E)
INTRODUCTION
This part of IEC 61850 defines the SCSM for sampled values over ISO/IEC 8802-3. The intent
of this SCSM definition is to supplement IEC 61850-9-1 to include the complete mapping of the
sampled value model.
This part of IEC 61850 applies to electronic current and voltage transformers (ECT and EVT
having a digital output), merging units, and intelligent electronic devices for example protection
units, bay controllers and meters.
Process bus communication structures can be arranged in different ways as described in
Annex B and IEC 61850-1. In addition to the transmission of sampled value data sets, which
are directly connected to ISO/IEC 8802-3, a selection of IEC 61850-8-1 services are necessary
to support the access to the SV control block. References to the relevant IEC 61850-8-1
services are provided in this SCSM. For less complex devices (for example merging units) the
sampled value control block can be pre-configured, in which case there is no need to
implement IEC 61850-8-1 services based on the MMS-Stack.
This document defines the mapping of sampled value class model (IEC 61850-7-2) to
ISO/IEC 8802-3. This SCSM, in combination with IEC 61850-7 and IEC 61850-6, allows
interoperability between devices from different manufacturers.
This standard does not specify individual implementations or products, nor does it constrain the
implementation of entities and interfaces within a computer system. This standard specifies the
externally visible functionality of implementations together with conformance requirements for
such functionalities.
Reading Guide
• This document is an extended mapping specification of IEC 61850-9-1 and IEC 61850-8-1
to cover sampled value transmission over ISO/IEC 8802-3.
• This document can best be understood if the reader is thoroughly familiar with IEC 61850-
7-1, IEC 61850-7-2, IEC 61850-7-3 and IEC 61850-7-4.
• The ACSI services defined in IEC 61850-7-2 are not explained in this part of the standard.

61850-9-2  IEC:2004(E) – 7 –
COMMUNICATION NETWORKS AND SYSTEMS IN SUBSTATIONS –

Part 9-2: Specific Communication Service Mapping (SCSM) –
Sampled values over ISO/IEC 8802-3

1 Scope
This part of IEC 61850 defines the Specific Communication Service Mapping (SCSM) for the
transmission of sampled values according to the abstract specification in IEC 61850-7-2. The
mapping is that of the abstract model on a mixed stack using direct access to an
ISO/IEC 8802-3 link for the transmission of the samples in combination with IEC 61850-8-1.
Each SCSM consists of three parts:
– a specification of the communication stack being used,
– the mapping of the abstract specifications of IEC 61850-7 on the real elements of the stack
being used, and
– the implementation specification of functionality, that is not covered by the stack being
used.
2 Normative references
The following referenced documents are indispensable for the application 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 60874-10-1, Connectors for optical fibres and cables – Part 10-1: Detail specification for
fibre optic connector type BFOC/2,5 terminated to multimode fibre type A1
IEC 60874-10-2, Connectors for optical fibres and cables – Part 10-2: Detail specification for
fibre optic connector type BFOC/2,5 terminated to single-mode fibre type B1
IEC 60874-10-3, Connectors for optical fibres and cables – Part 10-3: Detail specification for
fibre optic adaptor type BFOC/2,5 for single and multimode fibre
IEC 61850-7-1, Communication networks and systems in substations – Part 7-1: Basic
communication structure for substation and feeder equipment – Part 7-1: Principles and models
IEC 61850-7-2, Communication networks and systems in substations – Part 7-2: Basic
communication structure for substation and feeder equipment – Abstract communication
ACSI)
service interface (
IEC 61850-7-3, Communication networks and systems in substations – Part 7-3: Basic
communication structure for substation and feeder equipment – Common data classes
IEC 61850-7-4, Communication networks and systems in substations – Part 7-4: Basic
communication structure for substation and feeder equipment – Compatible logical node
classes and data classes
IEC 61850-8-1, Communication networks and systems in substations – Part 8-1: Specific
Communication Service Mapping (SCSM) – Mappings to MMS (ISO 9506-1 and ISO 9506-2) and
to ISO/IEC 8802-3
– 8 – 61850-9-2  IEC:2004(E)
IEC 61850-9-1, Communication networks and systems in substations – Part 9-1: Specific
Communication Service Mapping (SCSM) – Sampled values over serial unidirectional multidrop
point to point link
ISO/IEC 7498-1:1994, Information technology – Open Systems Interconnection – Basic
Reference Model: The Basic Model
ISO/IEC 8326:1996, Information processing systems – Open Systems Interconnection –
Session service definition
ISO/IEC 8327-1:1997, Information technology – Open Systems Interconnection – Connection-
oriented session protocols: Protocol specification
ISO/IEC 8649:1996, Information technology – Open Systems Interconnection – Service
definition for the Associated Control Service Element
ISO/IEC 8650-1:1996, Information technology – Open Systems Interconnection – Connection-
oriented protocol for the Association Control Service Element: Protocol specification
ISO/IEC 8802-3:2001, Information technology – Telecommunications and information exchange
between systems – Local and metropolitan area networks – Specific requirements – Part 3:
Carrier sense multiple access with collision detection (CSMA/CD) access method and physical
layer specifications
ISO/IEC 8822:1994, Information technology – Open Systems Interconnection – Presentation
service definition
ISO/IEC 8823-1:1994, Information technology – Open Systems Interconnection – Connection-
oriented presentation protocol: Protocol specification
ISO/IEC 8824-1:1999, Information technology – Abstract Syntax Notation One (ASN. 1):
Specification of basic notation
Amendment 1 (2000)
Amendment 2 (2000)
ISO/IEC 8825-1, Information technology – ASN.1 encoding rules: Specification of Basic
Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules
(DER)
ISO 9506-1:2003, Industrial automation systems – Manufacturing Message Specification –
Part 1: Service definition
ISO 9506-2:2003, Industrial automation systems – Manufacturing Message Specification –
Part 2: Protocol specification
IEEE 754:1985, IEEE Standard for Binary Floating-Point Arithmetic
IEEE 802.1Q:1998, IEEE Standards for Local and Metropolitan Area Networks: Virtual Bridged
Local Area Networks
RFC 791, Internet Protocol; IETF, available at
RFC 792, Internet Control Message Protocol; IETF, available at
RFC 793, Transmission Control Procedure; IETF, available at
RFC 826, An Ethernet Address Resolution Protocol or Converting Network Protocol Addresses
to 48.bit Ethernet Address for Transmission on Ethernet Hardware; IETF, available at

RFC 894, A Standard for the Transmission of IP datagrams over Ethernet Networks; IETF,
available at

61850-9-2  IEC:2004(E) – 9 –
RFC 919, Broadcasting Internet Datagrams; IETF, available at
RFC 1006 ISO transport services on top of TCP: Version 3; IETF, available at

RFC 1112, Host Extensions for IP Multicasting; IETF, available at
3 Terms and definitions
For the purposes of this document, the definitions given in IEC 61850-2 apply.
4 Abbreviations
ACSI Abstract Communication Service Interface
ASDU Application Service Data Unit
ASN.1 Abstract Syntax Notation number One
APCI Application Protocol Control Information
APDU Application Protocol Data Unit
APPID Application Identifier
AUI Attachment Unit Interface
BER ASN.1 Basic Encoding Rules
BS Bitstring
c Conditional support. The item shall be implemented if the stated condition exists
Canonical Format Identifier
CFI
Carrier Sense Multiple Access/Collision Detection
CSMA/CD
Data Frame
DF
Data Object
DO
Electronic Current Transformer
ECT
Electronic Voltage Transformer
EVT
Functional Standard
F/S
Generic Object Oriented Substation Event
GOOSE
Generic Substation Status Event
GSSE
i Out-of-scope: The implementation of the item is not within the scope of this
standard
ICD IED Configuration Description
Intelligent Electronic Device
IED
Link Layer Service Data Unit
LSDU
m Mandatory support. The item shall be implemented.
MAC Media Access Control
MAU Medium Attachment Unit
MMS Manufacturing Message Specification (ISO 9506)
MSVCB Multicast Sampled Value Control Block

– 10 – 61850-9-2  IEC:2004(E)
Merging Unit
MU
o Optional support. The implementor may decide to implement the item
Protocol Data Unit
PDU
Protocol Implementation Conformance Statement
PICS
Specific Communication Services Mapping
SCSM
r readable
Routing Information Field (ISO/IEC 8802-5)
RIF
Sampled Value
SV
Tag Control Information
TCI
Tag Protocol Identifier
TPID
Unicast Sampled Value Control Block
USVCB
VID VLAN Identifier
Virtual Local Area Network
VLAN
Virtual Manufacturing Device
VMD
w Writeable
x Excluded: The implementor shall not implement this item
Extensible Markup Language
XML
5 Communication stack
5.1 Overview of the protocol usage
The OSI reference model (ISO/IEC 7498-1) defines a model based upon the concept of
layering of communication functions. The model includes 7 layers and specifies the functional
requirements for each layer to achieve a robust communication system. The model does not
specify the protocols to be used to achieve the functionality, nor does it restrict the solution to a
single set of protocols.
Application
Presentation A-Profile
Session
Transport
Network
T-Profile
DataLink
Physical
IEC  096/04
Figure 1 – OSI reference model and profiles
The use of ISO Application (A-Profile) and Transport (T-Profile) Profiles (see Figure 1)
describes the various stack profiles. An ISO A-Profile is the set of specifications and
agreements relating to the upper three (3) layers of the ISO OSI reference model (for example
the application, presentation, and session layers). An ISO T-Profile is the set of specifications
and agreements relating to the lower four (4) layers of the ISO OSI reference model (for
example the transport, network, datalink and physical layers).

61850-9-2  IEC:2004(E) – 11 –
Two combinations of A-Profiles and T-Profiles are defined in order to support the transmission
of sampled values including the access to the associated SV control block, as specified in
IEC 61850-7-2. The two different combinations are used for:
• client/server services based on MMS in accordance to IEC 61850-8-1;
• SV services based on data link layer.
5.2 Client/server services and communication profiles
5.2.1 Client/server services
This client/server communication profile shall be used in addition to the SV communication
profile according to 5.3 if an access to the sampled value control block via client is required.
This profile shall be used for any implementation claiming conformance to this standard and
declaring support for one of the following IEC 61850-7-2 services in Table 1.
Table 1 – Service requiring client/server communication profile
IEC 61850-7-2 model IEC 61850-7-2 service
Server GetServerDirectory
Association Associate
Abort
Release
Logical device GetLogicalDeviceDirectory
Logical node GetLogicalNodeDirectory

GetAllDataValues
Data GetDataValues
SetDataValues
GetDataDirectory
GetDataDefinition
Data set GetDataSetValues
SetDataSetValues
CreateDataSet
DeleteDataSet
GetDataSetDirectory
SV class model
GetMSVCBValues
SetMSVCBValues
GetUSVCBValues
SetUSVCBValues
– 12 – 61850-9-2  IEC:2004(E)
5.2.2 A-Profile
Table 2 shows services and protocols of the A-Profile client/server.
Table 2 – Service and protocols for client/server communication A-Profile
Specification
OSI model layer m/o
Protocol
Name Service specification
specification
Application Manufacturing ISO 9506-1:2000 ISO 9506-2:2000 m
message
specification
Association control ISO/IEC 8649:1996 ISO/IEC 8650-1:1996 m
service element
Presentation Connection oriented ISO/IEC 8822:1994 ISO/IEC 8823-1:1994 m
presentation
Abstract syntax ISO/IEC 8824-1:1999 ISO/IEC 8825-1 m
Session Connection oriented ISO/IEC 8326:1996 ISO/IEC 8327-1:1997 m
session
There is only one T-Profile (TCP/IP) that may be used by the client/server A-Profile.
5.2.3 TCP/IP T-Profile
Table 3 shows services and protocols of the TCP/IP T-Profile client/server.
Table 3 – Service and Protocols for Peer TCP/IP T-Profile
Specification
OSI model
m/o
Service Protocol
layer
Name
specification specification
Transport ISO transport on top of TCP RFC 1006 m
Internet Control Message Protocol (ICMP) RFC 792 m
Transmission Control Protocol (TCP) RFC 793 m
Network Internet protocol RFC 791
Converting network protocol address RFC 826 (Address Resolution m
Protocol: ARP)
Broadcasting internet datagrams RFC 919 m
Host extensions for IP multicasting RFC 1112 m
DataLink Standard for the transmission of IP datagrams RFC 894 m
over Ethernet networks
Carrier Sense Multiple Access with Collision ISO/IEC 8802-3:2001 m
Detection (CSMA/CD)
Physical Fibre optic transmission system 100Base-FX ISO/IEC 8802-3:2001 c1
Basic optical fibre connector IEC 60874-10-1, IEC 60874-10-2 c1
and IEC 60874-10-3
NOTE This is the specification for the ST
connector.
c1 – Recommended, but future technology could be used.

61850-9-2  IEC:2004(E) – 13 –
5.3 SV service and communication profile
5.3.1 SV mapping overview
This SV communication profile shall be used for any implementation claiming conformance to
this standard and declaring support for one of the following IEC 61850-7-2 services in Table 4.
Table 4 – Service requiring SV communication profile
Model IEC 61850-7-2 service
Multicast sampled value class model
Multicast SV message
Unicast sampled value class model
Unicast SV message
5.3.2 A-Profile
Table 5 shows services and p
...