ABB REM545AG228AAAA｜Machine Protection Terminal｜

REF541KM115AAA

This integrated machine terminal is designed for the complete protection, control, measurement, and supervision of rotating electrical machines, including:

Small and medium-sized generators
Synchronous motors
Large asynchronous motors

It combines multiple protection, automation, monitoring, and communication functions into a single intelligent electronic device (IED), providing a complete solution for machine applications in industrial plants and power systems.

1. Application and Measurement System
Machine Protection Applications

The terminal is mainly applied for:

Generator protection
Motor protection
Generator-transformer unit protection
Industrial motor control and monitoring

It provides integrated functions for:

Electrical protection
Operational control
Energy measurement
Equipment condition monitoring
Substation communication
Voltage and Current Measurement

The terminal supports electrical measurement through:

Conventional instrument transformers:
Current transformers (CTs)
Voltage transformers (VTs)
Modern sensor technologies:
Current sensors
Voltage dividers

This flexibility allows installation in both traditional switchgear and modern sensor-based systems.

2. Human-Machine Interface (HMI)

The terminal provides flexible local operation through:

Integrated Local HMI

Features:

Fixed front-panel man-machine interface
Large graphic display
Local parameter setting
Measurement display
Alarm and event indication
Control operation
External Display Option

An external display module is available for:

Flexible switchgear mounting
Improved operator access
Customized panel installation
3. Extended Protection Functions

The machine terminal includes comprehensive protection functions for generators and motors.

Overcurrent and Earth-Fault Protection
Non-directional Overcurrent Protection

Provides protection against:

Phase faults
Short circuits
Excessive current conditions
Directional Overcurrent Protection

Provides improved selectivity by considering:

Fault current magnitude
Fault direction
Earth-Fault Protection

Protects against:

Stator insulation faults
Ground faults
Earth leakage currents
4. Voltage Protection Functions

Includes:

Overvoltage Protection

Protects against:

Generator voltage rise
Switching surges
Abnormal system conditions
Undervoltage Protection

Protects against:

Voltage collapse
Loss of supply conditions
Abnormal operating states
5. Special Motor and Generator Protection Functions

The terminal provides dedicated machine protection functions, including:

Protection Function Purpose
Voltage-controlled overcurrent protection Provides improved fault sensitivity under reduced voltage conditions
Differential protection High-speed internal fault protection using multiple differential principles
Underexcitation protection Prevents generator operation with insufficient excitation
Underimpedance protection Provides backup protection and line backup protection
Thermal overload protection Protects against excessive heating due to overload
Unbalanced load protection Protects against negative sequence currents and phase imbalance
Abnormal frequency protection Detects abnormal frequency operation
Reverse power protection Detects generator motoring conditions
Low forward power protection Protects against insufficient mechanical input
Motor start-up supervision Monitors motor starting sequence and prevents excessive starting stress
6. Control Functions

The terminal provides integrated control functions for switching equipment.

Supported functions include:

Local control
Remote control
Circuit breaker operation
Switchgear status indication
Interlocking functions
Synchronism Check (Synchro-check)

The synchro-check function ensures safe breaker closing by verifying:

Voltage magnitude difference
Frequency difference
Phase angle difference

before connecting equipment to the power system.

7. Electrical Measurement Functions

The terminal provides comprehensive measurement of:

Electrical Quantities

Measured values include:

Phase currents
Phase-to-phase voltages
Phase-to-neutral voltages
Neutral current
Residual voltage
Frequency
Power factor
Active power (MW)
Reactive power (Mvar)
Energy measurement (MWh/Mvarh)

These measurements support:

Operation monitoring
Energy management
Fault analysis
Maintenance planning