AQ-M255 Motor protection IED

The AQ-M255 offers a modular motor protection and control solution for larger and more important motors large I/O capacity. Up to 11 optional I/O or communication cards are available for extensive monitoring and control applications. Up to 16 RTD signals can be connected for thermal alarming and tripping. The AQ-M255 communicates using various protocols including IEC 61850 substation communication standard.

  • Three-phase overcurrent, 4 stages INST, DT or IDMT (50/51)
  • Earth-fault (sensitive), 4 stages INST, DT or IDMT (50/51N)
  • Directional overcurrent, 4 stages INST, DT or IDMT (67)
  • Directional (sensitive) earth-fault, 4 stages INST, DT or IDMT (67N)
  • Harmonic overcurrent / inrush blocking, 4 stages INST, DT or IDMT (50/51H, 68)
  • Current unbalance / broken conductor, 4 stages INST, DT or IDMT (46/46R/46L)
  • High/low impedance restricted earth fault / cable end differential (87N)
  • Motor thermal overload (49M)
  • Motor start-up / locked rotor supervision with speed switch (48, 14)
  • Restart inhibit / frequent starts (66/86)
  • Undercurrent/loss of load (37)
  • Power factor protection (55)
  • Mechanical jam (51M)
  • Overvoltage, 4 stages INST, DT or IDMT (59)
  • Undervoltage, 4 stages INST, DT or IDMT (27)
  • Zero sequence overvoltage, 4 stages INST, DT or IDMT (59N)
  • Negative/positive sequence overvoltage, 4 stages INST, DT or IDMT (47)
  • Over/under frequency, 8 stages INST or DT (81O/81U)
  • Over/Under/Reverse power (32/37/32R)
  • Breaker failure protection (50BF/52BF)
  • Arc protection (optional) (50ARC/50NARC)
  • Controllable objects: 10
  • 8 setting groups
  • Phase and residual currents (IL1, IL2, IL3, I01, I02)
  • Voltage measurements (UL1-UL3, U12-U31, U0, SS)
  • Current and voltage THD and harmonics (up to 31st)
  • Frequency (f)
  • Power (P, Q, S, pf)
  • Energy (E+, E-, Eq+, Eq-)
  • Circuit breaker wear (CBW)
  • Disturbance recorder (3.2 kHz)
  • Current transformer supervision (CTS)
  • Fuse failure (VTS)
  • Trip circuit supervision (TCS)
  • Event recording
  • Non-volatile disturbance records: 100
  • Non-volatile event records: 15000
  • Current inputs: 5
  • Voltage inputs: 4
  • Digital inputs: 3 (standard)
  • Output relays: 5+1 (standard)
  • Options (11 slots)
  • Digital inputs optional: +8/16/24/32/40/48/56/64/ 72/80/88
  • Digital outputs optional: +5/10/15/20/25
  • Arc protection (12 sensors +2xHSO +BI)
  • 2 x mA input + 68 x RTD input
  • Communication media (specified below)
  • RJ 45 Ethernet 100Mb (front standard)
  • RJ 45 Ethernet 100Mb and RS 485 (rear standard)
  • Double LC Ethernet 100Mb (option)
  • RS232 + serial bre PP/PG/GP/GG (option)
  • Communication protocols
  • IEC 61850
  • IEC 608705103/101/104
  • Modbus RTU, Modbus TCP/IP
  • DNP 3.0, DNP 3.0 over TCP/IP
  • SPA