Section 6
Differential protection
6.1
Line differential protection
IP13934-1 v1
6.1.1
Identification
M14844-1 v4
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Line differential protection 3 CT sets,
with in-zone transformers, 2-3 line ends
LT3CPDIF
3Id/I>
SYMBOL-HH V1 EN-US
87LT
Line differential logic
LDLPSCH
-
87L
6.1.2
Functionality
6.1.2.1
Line differential protection for 3 CT sets, 2-3 line ends, in-zone
transformer LT3CPDIF
M14932-3 v9
One three-winding power transformer can be included in the line differential
protection zone. In such application, the differential protection is based on the
ampere turns balance between the transformer windings. Three-winding
transformers are correctly represented with vector group compensations made in
the algorithm. The function includes 2
nd
and 5
th
harmonic restraint and zero-
sequence current elimination. The phase-segregated differential protection with
single-pole tripping is usually not possible in such applications.
IED
IED
IED
Protected zone
Comm. Channel
Comm. Channel
Comm. Channel
IEC05000042_2_en.vsd
IEC05000042 V2 EN-US
Figure 30:
Example of application on a three-terminal line with an in-line
power transformer in the protection zone
1MRK 505 394-UEN A
Section 6
Differential protection
Line differential protection RED650 2.2 IEC
85
Technical manual
Summary of Contents for RED650
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