Protection functions in stations B and C operate as slaves (differential function
switched off) so currents are sent to protection function in station A, and received
on channels 2 and 3. To inform the differential algorithm that currents are coming
from the LV sides of the transformers, TraAOnInpCh must be set to 2 and
TraBOnInpCh to 3 (channel1 is reserved for local measurement). This is to ensure
that proper turn ratio and vector group correction is done.
Setting example with a three-winding transformer in the protected
zone
IEC130002 96-1-en.vsdx
IED
IED
A
B
T
T
IEC13000296 V2 EN-US
Figure 40: Three-winding transformer in the zone
Settings
Station A Station B
PDIF L3TCPDIF L3TCPDIF
NoOfUsedCTs
3 3
T
raAOnInpCh
2 1
TraBOnInpCh
3 2
Currents from the secondary and tertiary windings of the power transformer are
connected to one line differential protection IED. Currents for each CT group are
sent to the IED at station A by the LDCM. To inform the differential algorithm that
currents are coming from the LV sides of the transformers, TraAOnInpCh must be
set to 2 and TraBOnInpCh to 3 (channel1 is reserved for local measurement). This
is to ensure that proper turn ratio and vector group correction is done.
4.7.2 Line differential protection L4CPDIF
4.7.2.1 Setting example with a two-end power line
GUID-4C105C98-F9FE-41B3-A7E0-FC5430EC141A v2
In this example, a two-end 220 kV and 200 km power line is protected using
L4CPDIF.
The protected zone is determined by CT positions. One three-phase CT group is
placed at one end of the power line, and another three-phase CT group is placed at
Section 4 1MRK 505 382-UEN B
Analog and binary signal transfer for line differential protection
48 Communication set-up 670/650 series 2.2
Application Guide
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