Ethernet, which is becoming more and more widely used in substations, in favour of RS485. Using Ethernet in the
substation offers many adv
antages, most significantly including:
● Ethernet allows high-speed data rates (currently 100 Mbps, rather than tens of kbps or less used by most
serial protocols)
● Ethernet provides the possibility to have multiple clients
● Ethernet is an open standard in every-day use
● There is a wide range of Ethernet-compatible products that may be used to supplement the LAN installation
(hubs, bridges, switches)
7.5.2 IEC 61850 INTEROPERABILITY
A major benefit of IEC 61850 is interoperability. IEC 61850 standardizes the data model of substation IEDs, which
allows inter
operability betw
een products from multiple vendors.
An IEC 61850-compliant device may be interoperable, but this does not mean it is interchangeable. You cannot
simply replace a product from one vendor with that of another without reconfiguration. However the terminology
is pre-defined and anyone with prior knowledge of IEC 61850 should be able to integrate a new device very quickly
without having to map all of the new data. IEC 61850 brings improved substation communications and
interoperability to the end user, at a lower cost.
7.5.3 THE IEC 61850 DATA MODEL
The data model of any IEC 61850 IED can be viewed as a hierarchy of information, whose nomenclature and
categorization is defined and standar
dized in the IEC
61850 specification.
V01008
Physical Device (network address)
Logical Device : IEDs 1 to n
LN1: XCBR LN2: MMXU
Logical Nodes : 1 to n
Data Objects
Data Attributes
stVal q t PhA PhCPhB
Pos A
Figure 208: Data model layers in IEC 61850
The levels of this hierar
chy can be described as follows:
Data Frame format
Layer Description
Physical Device
Identifies the actual IED within a system. Typically the device’s name or IP address can be used (for
example Feeder_1 or 10.0.0.2.
Logical Device
Identifies groups of related Logical Nodes within the Physical Device. For the MiCOM IEDs, 5 Logical
Devices exist: Control, Measur
ements, Protection, Records, System.
Chapter 18 - Communications P14x
446 P14xEd1-TM-EN-1