ABB RET 541 Product Manual page 25

Transformer Terminal
Stabilized restricted earth-fault protection, REF4A, I
Basic setting
Operate time
Ratio I2f/I1f>
2nd harmonic blocking
Operation accuracy of differential current
measurement
Operation accuracy of phase angle
measurement
Start time:
-injected currents
- internal time
- total time
Reset time
Reset ratio, typically
Retardation time (Total retardation time when
the current drops below the start value)
Operation time accuracy at definite time
mode
Residual overvoltage protection, low-set stage, ROV1Low, U
Start voltage
Operate time
Operation mode
Measuring mode
Operation accuracy
Start time:
-injected voltages
- internal time
- total time
Reset time
Reset ratio, typically
Retardation time
Operate time accuracy at DT mode
RET 541, RET 543, RET 545
> and REF4B, I
0 0
0.5...50%
0.04...300.00 s
10...50 %
Not in use / In use
Note! The values below apply when f/fn = 0.95...1.05
±4% of set value or ±0.02 x In
±2%
>2.0 x operating current:
<30 ms
<40 ms
40...1000 ms (depends on the minimum pulse width set for
the trip output)
0.98 (0.90...0.98)
<50 ms
±2% of set value or ±20 ms
>
0
2.0...20.0% of Un
0.05...300.00 s
Not in use
Definite time
Peak-to-peak
Fundamental frequency
Note! The values below apply when f/fn = 0.95...1.05
±2.5% of set value or ±0.01 x Un
>2 x start voltage:
<32 ms
<40 ms
40...1000 ms (depends on the minimum pulse width set for
the trip output)
0.95
Total time for blocking: < 25 ms
Total time when voltage drops below start value: < 50 ms
±2% of set value or ±20 ms
1MRS755543
>
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