ABB REM545 Machine Terminal REM545BG225AAA A

The ABB REM545 machine terminal (model REM545BG225AAA A) is a second‑generation numerical relay engineered for the protection, control, and monitoring of generator‑transformer blocks in utility and industrial power systems. It builds on the success of the REM 500 family, incorporating advanced algorithms and a flexible hardware platform to meet the evolving needs of modern power grids.

Comprehensive Protection Suite

This terminal offers a full range of protection functions essential for generator and transformer safety. Key elements include:

• Differential protection (87G, 87T): High‑impedance or biased differential with 2nd and 5th harmonic blocking to prevent maloperation during inrush and over‑excitation.

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

• Rotor earth fault protection: One‑stage or two‑stage with AC or DC injection.

• Overexcitation (V/Hz): Inverse‑time characteristic for generator and transformer.

• Distance protection (21): Optional zone protection for transmission lines connected to the unit transformer.

All protection elements are independently configurable and can be adapted to various generator types (steam, gas, hydro) and transformer connections.

Integrated Automation and Control

The REM545BG225AAA A includes a powerful programmable logic controller (PLC) functionality. Users can create custom automation schemes using the graphical configuration tool. The device controls circuit breakers, disconnectors, and tap changers directly via its binary outputs. It also supports synchronism check (25) and auto‑synchronizing for generator connection to the grid. The integrated synchro‑check ensures safe paralleling with adjustable phase angle, voltage, and slip limits.

Measurements and Disturbance Recording

The terminal continuously measures RMS currents, voltages, active/reactive power, power factor, and frequency. Accuracy class 0.5 for metering is maintained across a wide operating range. The disturbance recorder captures up to 120 seconds of fault data with sampling rates up to 32 samples/cycle. Comtrade files can be exported via the front port for detailed analysis.

Communication and Cybersecurity

Standard communication interfaces include two rear optical ports for IEC 61850‑8‑1 (GOOSE) and IEC 60870‑5‑103. The REM545 supports role‑based user authentication and event logging to comply with NERC CIP requirements. Redundant Ethernet connections ensure high availability in substation automation systems. The device also features an embedded web server for easy monitoring using a standard browser.

Mechanical and Environmental Specifications

• Case: 6U height, 19" width, suitable for flush or semi‑flush mounting.

• Operating temperature: -10°C to +55°C (extended range available).

• Binary inputs: 8 to 24, programmable for 24‑220 V DC.

• Output relays: 8 to 16, with high‑breaking capacity (30 A make, 8 A continuous).

With its robust design and comprehensive functionality, the ABB REM545BG225AAA A ensures reliable protection of critical generation assets, reducing the risk of costly damage and improving power system stability.