Description
The ABB REX521BBHGLB01C is a configuration-specific REX 521 numerical protection relay designed for protection, control, measurement, and monitoring in electrical distribution and industrial power systems. ABB documentation identifies REX 521 as a multifunction protection relay with configurable protection and control functions.
The relay can monitor current and voltage conditions, supervise breaker and circuit status, provide protection functions, and exchange information with a substation control or automation system. The exact functions available on the BBHGLB01C ordering code depend on its hardware and application configuration.
🔧 Main Function
REX 521 combines numerical protection with control and measurement functions in a compact relay platform. Its documented functions include current and voltage supervision, breaker control, trip-circuit supervision, circuit-breaker wear monitoring, event recording, and configurable protection functions.
The relay also provides local/remote control functions and diagnostic information, making it suitable for feeder and substation protection applications.
🏭 Typical Applications
• Medium-voltage feeder protection
• Distribution substations
• Industrial power systems
• Circuit-breaker protection and control
• Overcurrent and earth-fault protection
• Motor and transformer protection applications
• Substation automation
• Electrical equipment monitoring
📋 Product Datasheet
| Parameter | Specification |
|---|---|
| Manufacturer | ABB |
| Model | REX521 |
| Order Code | REX521BBHGLB01C |
| Product Type | Numerical Protection Relay |
| Relay Family | REX 521 |
| Main Function | Protection, Control & Measurement |
| Protection Functions | Configuration-dependent |
| Current Measurement | 3-Phase Current + Residual Current* |
| Voltage Measurement | Phase / Residual Voltage* |
| Digital Inputs | Configuration-dependent |
| Relay Outputs | Configuration-dependent |
| Breaker Control | Supported |
| Trip-Circuit Supervision | Supported |
| Event Recording | Supported |
| Communication | Configuration-dependent |
| Local HMI | Display + Keypad |
| Configuration | Application-dependent |
| Installation | Protection & Control Panel |
| Power Supply | Configuration-dependent |
| Country of Origin | Finland / ABB manufacturing location* |
*Exact electrical ratings, I/O count, communication interface, protection functions, dimensions, and power-supply configuration depend on the specific REX521 hardware and ordering configuration. ABB’s technical reference confirms the relay’s current/voltage supervision, breaker control, trip-circuit supervision, event recording, and configurable I/O functions.
⚡ Key Features
• Numerical protection technology
• Multifunction protection and control
• Current and voltage monitoring
• Circuit-breaker control
• Trip-circuit supervision
• Breaker-wear monitoring
• Event and disturbance recording
• Local/remote control capability
• Built-in self-diagnostics
• Configurable digital I/O
🔌 Communication & Integration
The REX 521 can be integrated into a substation automation system through its supported communication configuration. The relay provides status, measurement, protection, and control information to higher-level systems.
The documented function blocks include breaker status and commands, disconnector and earth-switch information, auxiliary inputs, relay outputs, current-input supervision, voltage-input supervision, and trip-circuit supervision.
🛠️ Installation Notes
Before installation, verify the complete identification REX521BBHGLB01C, hardware revision, auxiliary power supply, CT/VT configuration, I/O arrangement, communication interface, and protection settings.
CT wiring and polarity should be checked carefully. Incorrect phase assignment or CT polarity can cause incorrect protection measurements and unwanted operation.
After installation, verify the relay self-diagnostics, measured currents and voltages, binary inputs and outputs, breaker control, communication, and configured protection functions.
⚙️ Commissioning Checklist
• Verify relay order code
• Confirm hardware configuration
• Check auxiliary power
• Inspect CT/VT wiring
• Verify phase sequence and polarity
• Check digital inputs
• Test relay outputs
• Verify breaker control
• Test trip-circuit supervision
• Check communication
• Verify protection settings
• Review event records
⚠️ Compatibility Notice
The ABB REX521BBHGLB01C is a dedicated numerical protection relay, not a general-purpose PLC module. The suffix BBHGLB01C represents a specific ordering configuration, so replacement should be based on the complete original configuration rather than the basic REX521 model name alone.
For a replacement project, compare the hardware revision, power supply, CT/VT ratings, I/O configuration, communication interface, firmware, and protection application before commissioning.
📦 Product Identification
Brand: ABB
Model: REX521
Order Code: REX521BBHGLB01C
Product Type: Numerical Protection Relay
Function: Protection, Control, Measurement & Monitoring
Application: Feeder / Substation Protection
System: ABB REX 521
