AQ-T257 Transformer protection device
AQ-T257_web
AQ-T257_web

Description

AQ-T257 is a transformer protection device with a differential protection function and an integrated automatic voltage regulator function. The relay also provides complete current-based and voltage-based protection functions as well as full measurements. You can add up to nine (9) I/O or communication cards into the device for extensive monitoring and control applications. AQ-T257 communicates using various protocols, including the IEC 61850 substation communication standard.

The AQ-T257 transformer protection device has two software options: the “A” variant (AQ-T257A) includes all the protection functions for transformers including differential protection, while the “B” variant (AQ-T257B) also includes the automatic voltage regulator that allows you to control more than one transformer at the same time. For more details on the software options, please see the order code below.

Highlight:

  • A large I/O capacity.
  • Automatic/manual voltage regulating (AVR) and/or parallel voltage regulating.
  • Complete transformer protection.
  • 2nd and 5th harmonic blocking.
  • Automatic verification of a connection group and nominal value settings.
  • Overloading and through fault statistics for preventive maintenance.
  • Power and energy measurement accuracy of up to 0.2 %.
AQ-T257_web

Technical data

  • AQ-T257A – Standard transformer protection functionality
  • AQ-T257B – Standard transformer protection functionality + Transformer AVR (automatic voltage regulator)

  • Non-directional overcurrent (I>; 50/51) - 4 stages (INST, DT or IDMT)
  • Non-directional earth fault (I0>; 50N/51N) - 4 stages (INST, DT or IDMT)
  • Directional overcurrent (Idir>; 67) - 4 stages (INST, DT or IDMT)
  • Directional earth fault (I0dir>; 67N/32N) - 4 stages (INST, DT or IDMT)
  • Negative sequence overcurrent/ Phase current reversal/ Current unbalance (I2>; 46/46R/46L) - 4 stages (INST, DT or IDMT)
  • Harmonic overcurrent (Ih>; 50H/51H/68H) - 4 stages (INST, DT or IDMT)
  • Circuit breaker failure protection (CBFP; 50BF/52BF)
  • Overvoltage (U>; 59) - 4 stages (INST, DT or IDMT)
  • Undervoltage (U<; 27) - 4 stages (INST, DT or IDMT)
  • Neutral overvoltage (U0>; 59N) - 4 stages (INST, DT or IDMT)
  • Sequence voltage (U1/U2>/<; 47/27P/59PN) - 4 stages (INST, DT or IDMT)
  • Overfrequency and underfrequency (f>/<; 81O/81U) - 8 stages (INST or DT)
  • Rate-of-change of frequency (df/dt>/<; 81R) - 8 stages (INST, DT or IDMT)
  • Power protection (P, Q, S>/<; 32) - 4 stages (DT)
  • Volts-per-hertz overexcitation (V/Hz>; 24)
  • Pole slip/Out-of-step protection (78)
  • Resistance temperature detectors (RTD)
  • Transformer status monitoring
  • Transformer thermal overload (TT>; 49T)
  • Generator/transformer differential (Idx>; 87T/87M/87G)
  • Voltage memory
  • Programmable stage (PGx>/<; 99)
  • Arc protection (IArc>/I0Arc>; 50Arc/50NArc) (optional)

  • Number of objects to control and monitor: 10
  • Number of indicators to monitor: 10
  • Number of setting groups: 8
  • Switch-on-to-fault
  • Vector jump (Δφ; 78)
  • Automatic voltage regulator (AVR; 90)
  • Synchrocheck (ΔV/Δa/Δf; 25)

  • Number of object to contol and monitor: 10
  • Number of indicators to monitor: 10
  • Number of setting groups: 8
  • Automatic voltage regulator – parallel control (AVR; 90)
  • Switch-on-to-fault
  • Vector jump (Δφ; 78)
  • Synchrocheck (ΔV/Δa/Δf; 25)

  • Phase, sequence and residual currents (IL1, IL2, IL3, I01, I02)
  • Phase, sequence and residual voltages (UL1, UL2, UL3, U12, U23, U31, U0)
  • Frequency (f)
  • Power (P, Q, S, pf) and Energy (E+, E-, Eq+, Eq-)
  • Power and energy class 0.5
  • Power and energy measurement accuracy of up to 0.2 % (optional)
  • Current transformer supervision - 2 instances
  • Voltage transformer supervision (60)
  • Circuit breaker wear monitoring
  • Total harmonic distortion (current)
  • Total harmonic distortion (voltage)
  • Fault locator (21FL)
  • Measurement recorder
  • Measurement value recorder
  • Event recorder (max. 15 000 permanent event records)
  • Disturbance recorder (max. 100 records á 5 seconds at 3.2 kHz sampling)

  • Current inputs: 10
  • Voltage inputs: 4
  • Digital inputs (fixed): 3
  • Digital outputs (fixed): 5
  • Number of empty slots: 9
  • Digital inputs: +8/16/24/32/40/48/56/64/72 (optional)
  • Digital outputs: +5/10/15/20/25/30 (optional)
  • Milliampere I/O module (4 mA outputs + 1 mA input)
  • Arc protection module (4 sensors + 2 HSO + 1 BI)
  • Communication media (see "Communication" below)
  • External I/O modules (see "Accessories" below)

  • Communication inputs
  • RJ-45 100 Mbps Ethernet (front panel, fixed)
  • RJ-45 100 Mbps Ethernet and RS-485 (rear panel, fixed)
  • 2 x RJ-45 100 Mbps Ethernet with an IRIG-B input (optional)
  • 2 x ST 100 Mbps Ethernet with an IRIG-B input (optional)
  • 2 x LC 100 Mbps Ethernet (PRP/HSR) (optional)
  • RS-232 serial fiber (PP/PG/GP/GG) (optional)
  • Communication protocols
  • IEC 61850 (edition 1)
  • IEC 61850 (edition 2)
  • IEC 60870-5-101/104
  • IEC 60870-5-103
  • Modbus/RTU and Modbus/TCP
  • DNP3
  • SPA

  • AX007 External 6-channel 2-/3-wire RTD input module (pre-configured)
  • AX008 External 8-channel thermocouple and mA input module (pre-configured)
  • AX013 Raising frame (120 mm)
  • AX014 Raising frame (40 mm)
  • AX015 Wall mounting bracket

Additional material

Application Drawing

An application image for AQ-T257A transformer protection device, with one version drawn according to IEC standard symbols and the other according to IEEE/ANSI standard symbols.

Device Rear Image

Device rear image_AQ-257-AAAAAAAAA

Device and Cut-out Image

AQ-250 dimensions and cut-out

Order Code

Order code_T257x

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