ABB RET670 Product Manual page 51

ABB
Transformer protection RET670 ANSI
Pre-configured
Product version: 1.2
Differential protection
Table 25. Transformer differential protection T2WPDIF, T3WPDIF (87T)
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 In for I < In
± 1.0% of In for I > In
>95% -
IBase
(100-5000)% of ± 1.0% of set value
on high voltage winding
(10-60)% of IBase ± 1.0% of In
(5.0-100.0)% of ± 2.0% of In
fundamental differential
current
(5.0-100.0)% of ± 5.0% of In
fundamental differential
current
Wye or delta -
0–11 -
25 ms typically at 0 to 2 -
x Ib
20 ms typically at 2 to 0 -
x Ib
12 ms typically at 0 to 5 -
x Ib
25 ms typically at 5 to 0 -
x Ib
2 ms typically at 0 to 5 -
x Ib
1MRK 504 118-BUS A
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