ABB RET 541 - Page 28

Negative phase-sequence protection, low-set stage, NPS3Low, I
2
>, and
high-set stage, NPS3High, I
2
>>
Operation mode
Start value of negative-sequence current I2
Operate time
Operating characteristic constant K
(corresponds to the machine constant, equal
to the I
2
2
t constant of the machine as stated
by machine manufacturer)
Definite start time at inverse-time mode
Definite minimum operate time
Maximum operate time
Cooling time of the machine
Number of phases to be measured
Rotation direction
Drop-off time of the operate time counter
Not in use
Definite time
Inverse time
0.01...0.50 x In
0.1....120.0 s
5.0...100.0
0.1...60.0 s
0.1...120.0 s
500...10000 s
5...10000 s
2 or 3
Forward
Reverse
0...1000 ms
Operation accuracy
Start time:
- injected negative-seq. current
- internal time
- total time
Reset time
Reset ratio, typically
Retardation time
Operate time accuracy at DT mode
Accuracy class index E at IDMT mode,
typically
Note! The values below apply when f/fn = 0.95...1.05
±2.5% of set value or ±0.01 x In
= 2.00 x start value
<32 ms
<40 ms
70...1030 ms (depends on the minimum pulse width set for
the trip output)
0.96
<45 ms
±2% of set value or ±20 ms
±2% of the calculated ideal operate time or ±20 ms
Three-phase overvoltage protection, low-set stage, OV3Low, 3U>
Start voltage
Operate time
Time multiplier
Operation mode
Measuring mode
Operation hysteresis
0.10…1.60 x Un
0.05…300.0 s
0.05…1.00
Not in use
Definite time
A curve
B curve
Phase-to-phase voltages; peak-to-peak measurement
Phase-to-phase voltages; fundamental freq. measurement
Phase-to-earth voltages; fundamental freq. measurement
1.0...5.0%
Operation accuracy
Start time:
-injected voltages
- internal time
- total time
Reset time
Reset ratio
Retardation time
Operate time accuracy at DT mode
Accuracy class index E at IDMT mode,
typically
Note! The values below apply when f/fn = 0.95...1.05
±2.5% of set value
= 1.1 x start voltage
<42 ms
<50 ms
40...1000 ms (depends on the minimum pulse width set for
the trip output)
0.96 (range 0.95...0.99)
< 50 ms
±2% of set value or ±20 ms
±20 ms
Transformer Terminal RET 541, RET 543, RET 545
1MRS755543
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