Date Code 20080110 IEC 61850 Communications H-3
SEL-387E Instruction Manual
The IEC 61850 document set, available directly from the IEC at http://www.iec.ch, contains
information necessary for successful implementation of this protocol. SEL strongly recommends
that anyone involved with the design, installation, configuration, or maintenance of IEC 61850
systems be familiar with the appropriate sections of these documents.
IEC 61850 O
PERATION
Ethernet Networking
IEC 61850 and Ethernet networking model options are only available when ordering a new
SEL-387E. The options are not available as field upgrades. In addition to IEC 61850, the
Ethernet port provides support protocols and data exchange, including FTP and Telnet, to SEL
devices. Access the SEL-387E Port 5 settings to configure all of the Ethernet settings, including
IEC 61850 network settings.
The SEL Ethernet port supports IEC 61850 services, including transport of Logical Node objects,
over TCP/IP. The Ethernet port can coordinate a maximum of six concurrent IEC 61850
sessions.
Object Models
The IEC 61850 standard relies heavily on the Abstract Communication Service Interface (ASCI)
model to define a set of service and the responses to those services. In terms of network
behavior, abstract modeling enables all IEDs to act identically. These abstract models are used
to create objects (data items) and services that exist independently of any underlying protocols.
These objects are in conformance with the common data class (CDC) specification
IEC 61850-7-3, which describes the type and structure of each element within a logical node.
CDCs for status, measurements, controllable analogs and statuses, and settings all have unique
CDC attributes. Each CDC attribute belongs to a set of functional constraints that groups the
attributes into specific categories such as status (ST), description (DC), and substituted value
(SV). Functional constraints, CDCs and CDC attributes are used as building blocks for defining
Local Nodes.
UCA2 uses GOMSFE (Generic Object Models for Substation and Feeder Equipment) to present
data from station IEDs as a series of objects called models or bricks. The IEC working group
has incorporated GOMSFE concepts into the standard, with some modifications to terminology;
one change was the renaming of bricks to logical nodes. Each logical node represents a group of
data (controls, status, measurements, etc.) associated with a particular function. For example,
the MMXU logical node (polyphase measurement unit) contains measurement data and other
points associated with three-phase metering including voltages and currents. Each IED may
contain many functions such as protection, metering, and control. Multiple logical nodes
represent the functions in multifunction devices.
Logical nodes can be organized into logical devices that are similar to directories on a computer
disk. As represented in the IEC 61850 network, each physical device can contain many logical
devices, and each logical device can contain many logical nodes. Many relays, meters, and other
IEC 61850 devices contain one primary logical device where all models are organized.
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