ABB RET 541 Product Manual page 21

Transformer Terminal
Operation accuracy
Start time:
- injected currents
- internal time
- total time
Reset time
Reset ratio, typically
Retardation time
Operate time accuracy at DT mode
Three-phase underimpedance protection, low-set stage UI6Low, Z<,
and high-set stage UI6High, Z<<
Z-setting
Operate time
UI6High
Meas. signals (phase selection)
Measuring mode
Operation accuracy
Start time:
- injected impedance
- internal time
- total time
Reset time
Reset ratio
Retardation time
Operate time accuracy
Stabilized and instantaneous differential protection for transformers, Diff6T, 33
Basic setting; the lowest ratio of differential
and nominal current to cause a trip
Starting ratio; slope of the 2nd line of the
operating characteristics
Turn-point 1; turnpoint between the 1st and
2nd line of the operating characteristics
Turn-point 2; turnpoint between the 2nd and
3rd line of the operating characteristics
Tripping value of the instantaneous stage
Operation accuracy
Trip time:
- Injected currents
- internal time
- total time
Reset time
Reset ratio, typically
Retardation time
RET 541, RET 543, RET 545
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
±2.5% of measured voltage or ±0.01 x Un
±2
>2.0 x start current:
<42 ms
<50 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
0.01...60.00 p.u.
0.04...300.00 s
Not in use; In use
4 selections for ph-e voltages
7 selections for ph-ph voltages
(depends on the signals available)
Peak-to peak; Fund.freq.
Note! The values below apply when f/fn = 0.95...1.05
± 3.0% of set value or ± 0.02 p.u.
= 0.50 x Z-setting
<42 ms
<50 ms
70...1030 ms (depends on the minimum pulse width set for
the TRIP output)
Typ. 1.03
< 45 ms
± 2% of set value or ± 20 ms
5...50%
10...50%
0.5 x In
1.0...3.0 x In
5...30 x In
Note! The values below apply when f/fn = 0.95...1.05
Phase difference measurement: ±4
Stabilized stage: ±4% of set value or ±2% x In
Instantaneous stage: ±4% of set value or ±2% x In
>2.0 x operating current
<35 ms
<45 ms
60...1020 ms (depends on the minimum pulse width set for
the trip output)
0.98
< 40 ms
1MRS755543
21