IEC 61850-9-1:2003

INTERNATIONAL IEC
STANDARD
61850-9-1
First edition
2003-05
Communication networks and
systems in substations –
Part 9-1:
Specific Communication Service
Mapping (SCSM) –
Sampled values over serial unidirectional
multidrop point to point link
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INTERNATIONAL IEC
STANDARD
61850-9-1
First edition
2003-05
Communication networks and
systems in substations –
Part 9-1:
Specific Communication Service
Mapping (SCSM) –
Sampled values over serial unidirectional
multidrop point to point link
 IEC 2003  Copyright - all rights reserved
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– 2 – 61850-9-1  IEC:2003(E)
CONTENTS
FOREWORD . 4
INTRODUCTION .6
1 Scope . 7
2 Normative references. 8
3 Terms and definitions. 8
4 Abbreviations . 8
5 Principle of mapping to the serial unidirectional multidrop point to point link . 9
5.1 Communication stack. 9
5.1.1 Physical layer.10
5.1.2 Link layer .11
5.1.3 Network layer .12
5.1.4 Transport layer.12
5.1.5 Session layer .12
5.1.6 Presentation layer .12
5.1.7 Application layer.12
5.2 Restrictions.12
6 Mapping of common types.12
6.1 Object name .12
6.2 Object reference .12
7 Mapping of the model for transmission of sampled values using multicast.13
7.1 Mapping of the multicast sampled values services.13
7.2 Mapping of the update of the sampled value buffer.14
7.3 Additional definitions for the transmission of sampled analogue values .14
7.3.1 Application layer functionality .14
7.3.2 Presentation layer functionality.15
7.3.3 Transport layer functionality .15
8 Mapping of the common data classes.16
8.1 Overview .16
8.2 Additional definitions for the mapping of the common data classes .16
Annex A (normative) Definition of data set instances and related multicast sampled
value control instances .19
Annex B (informative) Calculation of required bandwidth.22
Annex C (informative) Definitions of logical node instance names and data names
related to the data sets .24
Annex D (informative) Electronic transformers block diagram and configuration example .28

61850-9-1  IEC:2003(E) – 3 –
Figure 1 – Example for the use of the serial unidirectional multidrop point to point link . 7
Figure 2 – Communication stack.10
Figure 3 – Concatenation of several ASDU’s into one APDU .14
Figure A.1 – Data set for status indication.20
Figure B.1 – Ethernet Frame Format.23
Figure C.1 – Contents of the universal data set based on the specification in IEC 60044-8 .27
Figure D.1 – Example for general block diagram of a single-phase electronic transformer .28
Figure D.2 – Example for electronic transformers configuration.29
Table 1 – Mapping of the object reference .13
Table 2 – Mapping of the multicast sampled value services.13
Table 3 – Encoding for the transmission of sampled value buffer .15
Table 4 – Extended common data class single point status information .16
Table 5 – Encoding of the common data class SPS used for the universal data set .16
Table 6 – Encoding of the common data class MV .17
Table 7 – Encoding of common data class SPS used for the status indication group.18
Table A.1 – Predefined multicast sampled value control block instances relating
to the transmission of the Universal Data Set according to IEC 60044-8.19
Table A.2 – Predefined multicast sampled value control block instances relating to the
transmission of status indications .21
Table B.1 – Selection guide for Ethernet physical layer (receiving node).22
Table B.2 – Selection guide for Ethernet physical layer (sending node) .22
Table C.1 – Definitions of logical instance name and data names related to the
universal data set .24
Table C.2 – Definitions of logical instance name and data names related to the status
indication data set .26

– 4 – 61850-9-1  IEC:2003(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_____________
COMMUNICATION NETWORKS AND SYSTEMS IN SUBSTATIONS –
Part 9-1: Specific Communication Service Mapping (SCSM) –
Sampled values over serial unidirectional multidrop
point to point link
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organisation for standardisation comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardisation in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organisations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organisation
for Standardisation (ISO) in accordance with conditions determined by agreement between the two
organisations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61850-9-1 has been prepared by IEC technical committee 57:
Power system control and associated communications.
The text of this standard is based on the following documents:
FDIS Report on voting
57/619/FDIS 57/636/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.

61850-9-1  IEC:2003(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 devices 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/IEC 9506-1 and ISO/IEC 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 relationship between IEC 60044-8 and this standard is as follows:
IEC 60044-8 defines a merging unit as interface to electronic current and voltage transformers.
Data objects provided by that merging unit are specified in IEC 60044-8. This standard
specifies a serial communication interface between the merging unit and equipment using the
digital output of the merging unit like protection or metering equipment. For the specification of
that serial interface, a subset of the abstract communication services defined in IEC 61850-7-2
are mapped on an ISO/IEC 8802-3 based communication link.
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 standard may be issued at a later date.
———————
Under consideration.
To be published.
– 6 – 61850-9-1  IEC:2003(E)
INTRODUCTION
This part of IEC 61850 applies to electronic current and voltage transformers (ECT and EVT)
with a digital output via a merging unit, for use with electronic measuring instruments and
electronic protective devices.
The transformer technology can be based on optical arrangements equipped with electronic
components, on air core coils (with or without a built-in integrator) or, on iron core coils
with integrated burden and used as a current to voltage converter, alone or equipped with
electronic components.
For digital output, this standard takes into account a point to point connection from the merging
unit to electronic measuring instruments and electronic devices.
This mapping 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.
Reading Guide
• The point to point transformer interface as defined here is based on the concepts described
in IEC 60044-8. This standard extends this concept and proposes an alternative link layer
to provide a solution for transmitting sampled measured values via Ethernet based
interfaces. For the definition and measurement of the accuracy, synchronisation methods,
data rates etc. of the transformers, refer to IEC 60044-8.
• This document can best be understood if the reader is thoroughly familiar with Parts 7-1,
7-2, 7-3 and 7-4 of this Standard.
• No explanations to the ACSI services are given in this part of the standard. For detailed
information about the use of the ACSI services, refer to IEC 61850-7-2.

61850-9-1  IEC:2003(E) – 7 –
COMMUNICATION NETWORKS AND SYSTEMS IN SUBSTATIONS –
Part 9-1: Specific Communication Service Mapping (SCSM) –
Sampled values over serial unidirectional multidrop
point to point link
1 Scope
This part of IEC 61850 specifies the specific communication service mappings for the
communication between bay and process level and it specifies a mapping on a serial
unidirectional multidrop point to point link in accordance with IEC 60044-8. This part of
IEC 61850 specifies a mapping of the abstract service for the transmission of sampled values
(as defined in IEC 61850-7-2) on a serial unidirectional multidrop point to point link in
accordance with IEC 60044-8. It applies to the communication between merging units of
electronic current (ECT) or voltage-transformers (EVT) and bay devices such as protection
relays. If higher requirements on sampling rate, further sampled measured value data sets in
addition to the universal data set, inter-bay communication and synchronisation apply, these
will be covered by IEC 61850-9-2 . Figure 1 shows the schematics of this interface.
Line protection Bay controller
Ethernet Ethernet
controller controller
Serial unidirectional
multidrop point to point link
Multiple
ports
Ethernet
Proprietary
Synchronisation, monitoring,
controller
link
test and configuration
interfaces
Merging unit
Proprietary
link
Binary inputs
IEC  812/03
Figure 1 – Example for the use of the serial unidirectional multidrop point to point link
———————
Under consideration.
– 8 – 61850-9-1  IEC:2003(E)
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 60044-7: Instrument Transformers – Part 7: Electronic voltage transformers
IEC 60044-8: Instrument Transformers – Part 8: Electronic current transformers
IEC 60874-10-1:1997, 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 61850-7-2: Communication networks and systems in substations – Part 7-2: Basic com-
munication structure for substation and feeder equipment – Abstract communication service
interface (ACSI)
IEC 61850-7-3: Communication networks and systems in substations – Part 7-3: Basic
communication structure for substation and feeder equipment – Common data classes
ISO/IEC 8802-3: 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 8825-1: Information technology – ASN.1 encoding rules: Specification of Basic Encoding
Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)
IEEE 802.1Q-1998: IEEE Standards for Local and Metropolitan Area Networks: Virtual Bridged
Local Area Networks
IEEE 802.3: Information Technology – Telecommunication and Information Exchange Between
Systems – LAN/MAN – Specific Requirements – Part 3: Carrier Sense Multiple Access with
Collision Detection (CSMA/CD) Access Method and Physical Layer Specifications
3 Terms and definitions
For the purpose of this part of IEC 61850, the definitions of IEC 61850-2 , IEC 60044-7 and
IEC 60044-8 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
AUI Attachment Unit Interface
BER ASN.1 Basic Encoding Rules
CFI Canonical format identifier
———————
Under consideration.
61850-9-1  IEC:2003(E) – 9 –
CSMA/CD Carrier Sense Multiple Access/Collision Detection
DF Data Frame
DO Data Object
DSG Data Set Group
ECT Electronic Current Transformers
EVT Electronic Voltage Transformers
LSDU Link Layer Service Data Unit
MAC Media Access Control
MSVCB Multicast Sampled Value Control Block
MU Merging Unit
PDU Protocol Data Unit
SBO Select Before Operate
SC Secondary Converter
SCSM Specific Communication Services Mapping
SIG Status Indication Group
SAV Sampled Analogue Value
TCI Tag Control Information
TPID Tag Protocol Identifier
VID VLAN Identifier
VLAN Virtual Local Area Network
5 Principle of mapping to the serial unidirectional multidrop
point to point link
This Clause gives an overview of the mapping to the serial unidirectional multidrop point to
point link. It defines the communication stack and data unit structures for the application layer.
Restrictions to the application that are a consequence of this mapping are defined as well.
5.1 Communication stack
Figure 2 gives an overview of the communication stack. The link layer is in conformity with
ISO/IEC 8802-3. This standard is usually referred to as Ethernet. In the following, the term
Ethernet will be used instead of ISO/IEC 8802-3 (CSMA/CD).

– 10 – 61850-9-1  IEC:2003(E)
SCSM for ISO/IEC 8802-3:
Application layer
Definition of ASDU's
Empty
Presentation layer
Empty
Session layer
Empty
Transport layer
Empty
Network layer
MAC - Sublayer
ISO/IEC 8802-3
Link layer
and
Priority tagging/VLAN according
to IEEE 802.1Q
AUI-Interface
IEEE 802.3
100Base-FX 10Base-FL 10Base-T
IEEE 802.3 IEEE 802.3 IEEE 802.3
Physical layer
IEC  813/03
Figure 2 – Communication stack
The relevant device standards will specify whether 100Base-FX, 10Base-FL or 10Base-T is used,
depending on the application.
5.1.1 Physical layer
5.1.1.1 Specifications for the Medium Attachment Unit (MAU)
The connection of the merging unit to the secondary equipment can be an optical fibre
transmission system. By taking into account and solving the EMC requirements, a copper
based transmission system is an option.
5.1.1.2 Fibre optic transmission system
The preferred version of the fibre optic transmission system is IEEE 802.3 100Base-FX. The
10Base-FL system could be used also for sampling rates below 48 × f (a selection guide
r
is given in Annex B). This interface shall be used for applications where this media interface is
already used for other communication links. It is recommended to use the BFOC connectors
(IEC 60874-10-1). Two fibres are always necessary for the optical fibre transmission system in
order to support the link supervision.
5.1.1.3 Twisted-pair transmission system
The twisted-pair medium according to IEEE 802.3 10Base-T could be used as an option, if
appropriate electromagnetic shield measures are considered.

61850-9-1  IEC:2003(E) – 11 –
5.1.2 Link layer
5.1.2.1 Ethernet addresses
The Ethernet broadcast address shall be used as a default value for a destination address,
which consists of ones in the destination address field (the Ethernet frame format is shown in
Annex B). For this reason, no address configuration is necessary on the publisher side.
However, the destination address could be configurable as an optional feature for example,
adjust a multicast address to connect a merging unit via switch to bay level devices. A unique
Ethernet address shall be used as a source address.
NOTE The recommended address range assignments will be specified in IEC 61850-9-2 and IEC 61850-8-1.
5.1.2.2 Priority tagging/Virtual LAN
Priority tagging according to IEEE 802.1Q is used to separate time critical and high priority bus
traffic for protection relevant applications from low priority busload.
Structure of the tag header:
Key
Octets 8 76 54321
TPID value: 0x8100
User priority: BS3; user priority value shall be set by
TPID 0x8100
configuration to separate sampled analogue values
and time critical protection relevant GOOSE
messages from low priority busload.
3 Us er priorityCFI VID
TCI
CFI: BS1 [0]; No Embedded RIF field follows the
4 VID
length/type field in the Ethernet tagged frame.
VID: Virtual LAN support is optional. If this
mechanism is used, the VLAN identifier (VID) shall
be set by configuration. Otherwise, the VLAN
identifier is set by default to 0.
5.1.2.3 Ethertype
An Ethertype based on ISO/IEC 8802-3 MAC – Sublayer is registered by the IEEE Authority
Registration. The registered Ethertype value is 88-BA (hexadecimal). The sampled analogue
value buffer update is directly mapped to the reserved Ethertype and the Ethertype PDU.
Structure of the Ethertype PDU:
Key
Octets 8 76 54321
APPID: application identifier. The APPID is used to
1 E thertype
select sampled analogue value messages and to
distinguish the application association.
Reserved value range for SAV are 0x4000 to
3 APPID
0x7FFF.
Length: number of octets including the Ethertype
PDU starting at APPID (8 + m) (m < 1480).
5 Lengt h
Reserved 1/Reserved 2: reserved for future
Ether-
standardised applications.
type
7 Res erved 1
PDU
9 Res erved 2
... APDU
m+2
– 12 – 61850-9-1  IEC:2003(E)
5.1.3 Network layer
This layer is intentionally left empty.
5.1.4 Transport layer
This layer is intentionally left empty.
5.1.5 Session layer
This layer is intentionally left empty.
5.1.6 Presentation layer
Empty. See additional definitions in 7.3.
5.1.7 Application layer
Empty. See additional definitions in 7.3.
5.2 Restrictions
This specification is restricted to define the communication between the ECT/EVT related
merging unit and devices on bay level which need raw data of ECT and/or EVT for their
algorithms. Referring to the ACSI, only the mapping of sampled values using multicast/
broadcast is supported. The multicast sampled value control (MSVC) class is implicit.
The transmission of sampled values as specified in this standard only uses a unidirectional link
from merging unit to bay level devices with broadcast/multicast addressing. However, the
devices suppo
...