ABB REM545AG225AAA A REV A Machine Terminal

The ABB REM545AG225AAA A REV A is a numerical machine terminal specifically designed for the protection, control, and monitoring of generator-transformer units in power generation applications. As part of ABB’s renowned REM 500 series, this REV A version incorporates enhanced algorithms and refined hardware to meet the demanding requirements of modern power plants, including thermal, hydro, and gas turbine installations.

Generator-Transformer Protection

The REM545AG225AAA A provides a comprehensive suite of protection functions essential for safeguarding generators and step-up transformers. Core protection includes:

• Differential protection (87G, 87T): High-impedance or biased differential with second and fifth harmonic restraint to prevent misoperation during inrush and overexcitation.

• Stator earth fault protection: 95% and 100% coverage using third-harmonic voltage and injection methods.

• Rotor earth fault protection: Single or two-stage with AC/DC injection.

• Overexcitation (V/Hz): Inverse-time characteristic with definite time limit.

• Overcurrent (50/51), negative sequence overcurrent (46), directional power (32), under/overvoltage (27/59), and under/overfrequency (81U/O).

All protection elements are independently configurable with adjustable curves and thresholds to match the protected equipment’s capability curves.

Control and Automation

The terminal includes a powerful programmable logic controller (PLC) that enables users to create customized interlocking, sequencing, and automation schemes. It supports synchronism check (25) and auto-synchronizing for generator connection to the grid, with adjustable phase angle, voltage, and slip limits. The device also controls circuit breakers, disconnectors, and tap changers directly via its binary outputs. The integrated disturbance recorder captures fault waveforms for detailed analysis.

Measurements and Monitoring

The REM545AG225AAA A continuously measures RMS currents, voltages, active/reactive power, power factor, frequency, and energy. Accuracy class 0.5 for metering ensures precise monitoring. The unit also monitors generator and transformer temperatures via RTD inputs and provides alarms or trips based on user-defined thresholds. Breaker condition monitoring and trip circuit supervision enhance maintenance planning.

Communication Interfaces

This REV A model features two rear communication ports supporting protocols such as IEC 61850, IEC 60870-5-103, Modbus RTU, and DNP3.0. Redundant Ethernet options are available for high availability in substation automation systems. Time synchronization via IRIG-B or SNTP ensures accurate event time-stamping. The front panel includes an HMI with graphical LCD and keypad for local operation and configuration.

Technical Data

• Measuring inputs: 4 current (1/5 A) and 4 voltage (100-230 V AC).

• Binary I/O: Up to 24 binary inputs and 16 output relays, depending on configuration.

• Power supply: 80-265 V DC or 100-240 V AC.

• Case: 6U high, 19" rack or flush mount, IP54 front.

• Operating temperature: -10°C to +55°C.

Application

The REM545AG225AAA A REV A is ideal for protecting generator-transformer blocks in utility power stations, industrial co-generation plants, and renewable energy installations. Its advanced features and robust design ensure reliable operation and help minimize costly damage to generation assets.