Pick-up
Df/dt>/< pick-up setting
f> limit
f< limit
0.15…1.00 Hz/s, setting step 0.01 Hz
10.00…70.00 Hz, setting step 0.01 Hz
7.00…65.00 Hz, setting step 0.01 Hz
Inaccuracy
-df/dt
-frequency
±5.0 %I
SET
or ±20 mHz/s
±15 mHz (U > 30 V secondary)
±20 mHz (I > 30 % of rated secondary)
Operation time
De nite time function operating time setting
0.00…1800.00 s, setting step 0.005 s
Inaccuracy
-De nite Time (Im/Iset ratio +/- 50mHz)
±1.5 % or ±110 ms (max step size 100mHz)
Instant operation time
Start time and instant operation time (trip):
(fm/fset ratio +/-20mHz overreach)
<200 ms
(fm/fset ratio +/- 200mHz overreach)
<90 ms
Reset
Reset ratio (Frequency limit)
df/dt
0.020 Hz
0.100 Hz/s of pick-up or 0.100 Hz/s absolute at low end
Instant reset time and start-up reset
(fm/fset ratio +/- 50mHz)
<325 ms (max step size 100mHz)
Note!
Frequency is measured 2 seconds after a signal is received.
9.2.1.15. Transformer thermal overload (49T) T>
Table. 9.2.1.15. - 276. Transformer thermal overload (49T) technical data
Input signals
Input current magnitude
Phase current TRMS max (31 harmonic)
Setting speci cations
Time constants τ
1 heating, 1 cooling
Time constant value
0.0…500.00 min by step of 0.1 min
Service factor (max overloading)
0.01…5.00 by step of 0.01 x In
Thermal model biasing
- Ambient temperature (Set -60.0 … 500.0 deg by step of 0.1 deg and RTD)
- Negative sequence current
Thermal replica temperature estimates
- Selectable deg C or deg F
Outputs
- Alarm 1 (0…150% by step of 1%)
- Alarm 2 (0…150% by step of 1%)
- Thermal Trip (0…150% by step of 1%)
Trip delay (0.000…3600.000s by step of 0.005s)
- Restart Inhibit (0…150% by step of 1%)
Inaccuracy
- Starting
- Operating time
±0.5% of set pick-up value
±5 % or ± 500ms
AQ-T257
Instruction manual
Version: 2.00
345
© Arcteq Relays Ltd
