AQ-T257 Transformer Protection IED
AQ-T257 is a transformer protection IED with differential protection function and integrated AVR function. The AQ-T257 transformer protection IED provides also for complete current and voltage based protection functions and full measurements. Up to 9 optional I/O or communication cards are available for extensive monitoring and control applications. The AQ-T257 communicates using various protocols including IEC 61850 substation communication standard.
Highlight
- Large I/O capability 2nd and 5th harmonic blocking
- Automatic / manual voltage regulating (AVR)
- Complete transformer protection
- 2nd and 5th harmonic blocking
- Automatic verification of connection group and nominal value settings
- Through fault and overloading statistics for preventive maintenance
- Up to class 0.2S power and energy measuring
| Protection |
|---|
| 2 winding transformer differential (87T) |
| High/low impedance restricted earth fault / cable end differential * (87N1, 87N2) |
| Transformer thermal overload (49T/49RTD) |
| Three-phase overcurrent, 2+2 stages INST, DT or IDMT (50/51) |
| Earth-fault (sensitive), 3 stages INST, DT or IDMT (50/51N) |
| Harmonic overcurrent / inrush blocking, 4 stages INST, DT or IDMT (50/51H, 68) |
| Current unbalance / broken conductor, 2+2 stages INST, DT or IDMT (46/46R/46L) |
| Directional overcurrent, 4 stages INST, DT or IDMT (67) |
| Directional (sensitive) earth-fault, 4 stages INST, DT or IDMT (67N) |
| Overvoltage, 2 stages INST, DT or IDMT (59) |
| Undervoltage, 2 stages INST, DT or IDMT (27) |
| Zero sequence overvoltage, 2 stages INST, DT or IDMT (59N) |
| Positive/Negative sequence overvoltage, 2 stages INST, DT or IDMT (59N/47) |
| Over/under frequency, 4 stages INST or DT (81O/81U) |
| Rate of change of frequency, 4 stages INST or DT or IDMT (81R) |
| Volts per hertz (24) |
| Breaker failure protection (50BF/52BF) |
| Arc protection (option) (50ARC/50NARC) |