that the cross block signals from the other two phases B and C is not activated to obtain a
trip on the TRIPRES_A output signal in figure 42)
6. All pickup and blocking conditions are available as phase segregated as well as common (that
is three-phase) signals.
ANSI06000546-2-en.vsd
&
IDiffAlarm
a
a>b
b
IDMAG_C Diff
IDiffAlarm
a
a>b
b
IDMAG_B Diff
IDiffAlarm
a
a>b
b
IDMAG_A Diff
IDALARM
0
0-tAlarmDelay
ANSI06000546 V2 EN-US
Figure 46: Differential current alarm logic
6.1.8 Technical data
IP12646-1 v1
M13046-1 v14
Table 58: T2WPDIF/T3WPDIF (87T) technical data
Function Range or value Accuracy
Operating characteristic Adaptable ±1.0% of In at I ≤ In
±1.0% of I at I > In
Reset ratio > 90% -
Unrestrained differential current
limit
(100-5000)% of
IBase
on high
voltage winding
±1.0% of set value
Minimum pickup (10-60)% of IBase ±1.0% of In
Second harmonic blocking (5.0-100.0)% of fundamental
differential current
±1.0% of I
n
Note: Fundamental magnitude =
100% of I
n
Fifth harmonic blocking (5.0-100.0)% of fundamental
differential current
±5.0% of I
n
Note: Fundamental magnitude =
100% of I
n
Connection type for each of the
windings
Wye or delta -
Phase displacement between high
voltage winding, W1 and each of the
windings, W2 and W3. Hour notation
0–11 -
*Trip time at 0 to 10 x IdMin,
restrained function
Min. = 25 ms
Max. = 35 ms
-
*Reset time at 10 x IdMin to 0,
restrained function
Min. = 5 ms
Max. = 15 ms
-
Table continues on next page
1MRK 502 066-UUS B Section 6
Differential protection
143
Technical manual
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