ABB RET 541 Product Manual page 19

Transformer Terminal
Table 7: Protection function blocks
Three-phase non-directional overcurrent protection, low-set stages, NOC3Low, 3I>,
NOC3LowB,3I>
Start current
Operate time at DT mode
Time multiplier at IDMT mode
Operation mode
Measuring mode
Drop-off time of the operate time counter
Operation accuracy
Start time:
- Injected currents
- internal time
- total time
Reset time
Reset ratio, typically
Retardation time
Operate time accuracy at DT mode
Accuracy class index E at IDMT mode
Three-phase non-directional overcurrent protection, high-set stage, NOC3High, 3I>>, and
instantaneous stage, NOC3Inst, 3I>>>
Start current
Operate time
Operation mode
Measuring mode
Drop-off time of the operate time counter
Operation accuracy
Start time:
- injected currents
- internal time
- total time
Reset time
Reset ratio, typically
Retardation time
Operate time accuracy at DT mode
RET 541, RET 543, RET 545
0.10...5.00 x In
0.05...300.00 s
0.05...1.00
Not in use
Definite time
Extremely inverse
Very inverse
Normal inverse
Long time inverse
RI-type inverse
RD-type inverse
IEEE curves
Peak-to-peak
Fundamental frequency
0...1000 ms
Note! The values below apply when f/fn = 0.95...1.05
±2.5% of set value or ±0.01 x In
>2.0 x start current:
<32 ms
<40 ms
40...1000 ms (depends on the minimum pulse width set for
the trip output)
0.95
< 45 ms
±2% of set value or ±20 ms
Class index E = 5.0 or ±20 ms
0.10...40.00 x In
0.05...300.00 s
Not in use
Definite time
Instantaneous
Peak-to-peak
Fundamental frequency
0...1000 ms
Note! The values below apply when f/fn = 0.95...1.05
0.1...10 x In: ±2.5% of set value or ±0.01 x In
10...40 x In: ±5.0% of set value
>2.0 x start current:
<32 ms
<40 ms
40...1000 ms (depends on the minimum pulse width set for
the trip output)
0.95
< 45 ms
±2% of set value or ±20 ms
1MRS755543
19