ABB Relion 670 Series Applications Manual page 461

1MRK 511 358-UUS A
18.3 IEC 61850-9-2LE communication protocol
18.3.1 Introduction
Every IED can be provided with communication interfaces enabling it to connect to the process
buses in order to get data from analog data acquisition units close to the process (primary
apparatus), commonly known as Merging Units (MU). The protocol used in this case is the
IEC/UCA 61850-9-2LE communication protocol.
The IEC/UCA 61850-9-2LE standard does not specify the quality of the sampled values. Thus, the
accuracy of the current and voltage inputs to the merging unit and the inaccuracy added by the
merging unit must be coordinated with the requirement for the actual type of protection function.
Set the CD-port to 9–2LE communication using only LHMI. All other settings are also available from
PCM600.
Factors influencing the accuracy of the sampled values from the merging unit are, for example,
anti aliasing filters, frequency range, step response, truncating, A/D conversion inaccuracy, time
tagging accuracy etc.
In principle, the accuracy of the current and voltage transformers, together with the merging unit,
will have the same quality as the direct input of currents and voltages.
The process bus physical layout can be arranged in several ways, described in Annex B of the
standard, depending on what are the needs for sampled data in a substation.
SDM600
IEC18000011 V1 EN-US
Figure 213: Example of a station configuration with separated process bus and station bus
The IED can get analog values simultaneously from a classical CT or VT and from a Merging Unit,
like in this example:
Application manual
Network Control Center
Maintenance Center
Engineering
Computer HMI
Firewall
Workstation
VPN
AFS 6xx
AFS 6xx
SAM600
SAM600
Printer
Events Printer
WAMS
AFS 6xx
Gateway
AFS 6xx
SAM600
Station communication
IEC 6185 0
FOX615
NSD570
IET600 PCM600 ITT600
IEC18000011-1-en.vsdx
Section 18
SEMOD172279 v2
SEMOD166571-1 v2
SEMOD166590-5 v7
455