Differential protection
Table 23. Transformer differential protection T2WPDIF, T3WPDIF
Function Range or value Accuracy
Operating characteristic Adaptable ±1.0% of Ir at I ≤ Ir
±1.0% of I at I > Ir
Reset ratio > 90% -
Unrestrained differential current limit (100-5000)% of
IBase
on high voltage
winding
±1.0% of set value
Minimum pickup (5-60)% of IBase ±1.0% of Ir
Second harmonic blocking (5.0-100.0)% of fundamental
differential current
±1.0% of I
r
Note: fundamental magnitude = 100% of I
r
Fifth harmonic blocking (5.0-100.0)% of fundamental
differential current
±5.0% of I
r
Note: fundamental magnitude = 100% of I
r
Connection type for each of the windings Y or D -
Phase displacement between high
voltage winding, W1 and each of the
windings, W2 and W3. Hour notation
0–11 -
*Operate time at 0 to 10 x IdMin,
restrained function
Min. = 25 ms
Max. = 35 ms
-
*Reset time at 10 to 0 x IdMin, restrained
function
Min. = 5 ms
Max. = 15 ms
-
*Operate time at 0 to 10 x Idunre,
unrestrained function
Min. = 5 ms
Max. = 15 ms
-
*Reset time at 10 to 0 x Idunre,
unrestrained function
Min. = 15 ms
Max. = 30 ms
-
**Operate time, unrestrained negative
sequence function
Min. = 10 ms
Max. = 20 ms
-
**Reset time, unrestrained negative
sequence function
Min. = 10 ms
Max. = 30 ms
-
Critical impulse time 2 ms typically at 0 to 5 x IdMin -
*Note: Data obtained with single input current group.
**Note: Data obtained with two input current groups. The rated symmetrical currents are applied on both sides as pre- and after-fault currents. The
fault is performed by increasing one phase current to double on one side and decreasing same phase current to zero on the other side.
Transformer protection RET670 2.0
1MRK 504 141-BEN C
Product version: 2.0
ABB 53
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