ABB RET670 Product Manual page 49

ABB
Transformer protection RET670
Customized
Product version: 1.2
Differential protection
Table 27. Transformer differential protection T2WPDIF, T3WPDIF
Function
Operating characteristic
Reset ratio
Unrestrained differential current limit
Base sensitivity function
Second harmonic blocking
Fifth harmonic blocking
Connection type for each of the windings
Phase displacement between high voltage
winding, W1 and each of the windings, W2
and W3. Hour notation
Operate time, restrained function
Reset time, restrained function
Operate time, unrestrained function
Reset time, unrestrained function
Critical impulse time
Range or value Accuracy
Adaptable ± 1.0% of Ir for I < Ir
± 1.0% of I for I > Ir
>95% -
IBase
(100-5000)% of ± 1.0% of set value
on high voltage winding
(10-60)% of IBase ± 1.0% of Ir
(5.0-100.0)% of ± 2.0% of applied harmonic magnitude
fundamental differential
current
(5.0-100.0)% of ± 5.0% of applied harmonic magnitude
fundamental differential
current
Y or D -
0–11 -
25 ms typically at 0 to 2 -
x set level
20 ms typically at 2 to 0 -
x set level
12 ms typically at 0 to 5 -
x set level
25 ms typically at 5 to 0 -
x set level
2 ms typically at 0 to 5 -
x Ib
1MRK 504 117-BEN D
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