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IEC13000296-1-en.vsd
RED
670
RED
670
A
B
T
T
IEC13000296 V1 EN-US
Figure 68: Three-winding transformer in the zone
Settings
Station A
Station B
PDIF
L3TC PDIF
L3TC PDIF
NoOfUsedCTs
3
3
T
raAOnInpCh
2
1
TraBOnInpCh
3
2
The currents from the secondary and tertiary windings of the power transformer are
connected to one RED670. The currents for each CT group are sent to the RED670 at A station
by the LDCM. To inform the differential algorithm that the currents are from the low voltage
sides of the transformer,
TraAOnInpCh has to be set to 2 and TraBOnInpCh to 3 (channel1 is
reserved for local measurement) so that the proper turn ratio and vector group correction can
be done.
6.4
Additional security logic for differential protection
LDRGFC
GUID-0E064528-0E70-4FA1-87C7-581DADC1EB55 v2
6.4.1
Identification
GUID-3081E62B-3E96-4615-97B8-2CCA92752658 v2
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Additional security logic for
differential protection
LDRGFC
-
11
6.4.2
Application
GUID-93AF4444-C7ED-4DF5-9379-176DF17AE22C v4
Additional security logic for differential protection LDRGFC can help the security of the
protection especially when the communication system is in abnormal status or for example
when there is unspecified asymmetry in the communication link. It reduces the probability for
mal-operation of the protection. LDRGFC is more sensitive than the main protection logic to
always release operation for all faults detected by the differential function. LDRGFC consists
of four sub functions:
•
Phase-to-phase current variation
•
Zero sequence current criterion
•
Low voltage criterion
•
Low current criterion
1MRK 505 343-UEN B
Section 6
Differential protection
141
Application manual
Summary of Contents for Relion 670 series
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