ABB RET 541 Product Manual page 31

Transformer Terminal
Underfrequency or overfrequency protection, 5 stages, Freq1St1... Freq1St5, f</f>, df/dt
Operation mode
Undervoltage limit for blocking
Start value for under-/overfrequency prot.
Operate time for under-/overfrequency prot.
Start value for df/dt protection
Operate time for df/dt protection
Operation accuracy
- Frequency rate of change (df/dt):
- real df/dt
- real df/dt
- Undervoltage blocking
Start time:
- total start times at fn = 50 Hz:
- frequency measurement
- df/dt measurement
Reset time
Operate time accuracy
Overexcitation protection, low-set stage, OE1Low, U/f>, and high-set stage, OE1High, U/f>>
U/f start (DT mode)
U/f start (IDMT mode)
U max cont.
Operate time
k
Maximum time
Constant delay
Cooling time
Operation mode
Operation accuracies
Start time:
- Injected U/f
- internal time
- total time
Reset time
Reset ratio:
- 20...40 Hz
- 40...80 Hz
Retardation time
Operate time accuracy at definite-time mode
Operate time accuracy at inverse-time modes
RET 541, RET 543, RET 545
Not in use
f</f> 1 timer
f</f> 2 timers
f</f> OR df/dt>
f</f> AND df/dt>
f</f> OR df/dt<
f</f> AND df/dt<
0.30...0.90 x Un
25.00...75.00 Hz
0.10...120.00 s
0.2...10.0 Hz/s
0.12...120.00 s
Under-/overfrequency (f</f>): ±10 mHz
<±5 Hz/s: ±100 mHz/s
<±15 Hz/s: ±2.0% of real df/dt
±1.0% of set value
<100 ms
<120 ms
140...1000 ms (depends on the minimum pulse width set
for the trip output)
±2% of set value or ±30 ms
1.00...2.00 x U/f
1.00...2.00 x U/f
0.80...1.60 x Un
0.10...600.00 s
0.1...100.0
500...10000 s
0.1...120.0 s
5...10000 s
Not in use; Definite time; Curve#1; Curve#2
20...40 Hz: 4% of set value; 40...80 Hz: ±2% of set value
>2.0 x Un/fn
<60 ms,
<70 ms
100...1060 ms (depends on the set minimum pulse width
for the TRIP output)
typ. 0.99
typ 0.97
<105 ms
20...80 Hz: ±4% of set value or ±40 ms
±100 ms or the accuracy appearing when the measured
voltage varies ±1.0%
1MRS755543
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