Basler BE1-851 Digital Overcurrent Relay

The Basler BE1-851 is a digital overcurrent relay designed for protection of generators, transformers, and feeders in industrial and utility power systems. This relay provides phase overcurrent and ground fault protection with programmable time‑current curves, offering precise coordination and reliable fault clearing. The BE1-851 operates on a wide supply range of 48‑125 V AC/DC, making it suitable for various control power configurations.

The relay features microprocessor‑based measurement with high accuracy and programmable settings. It includes a front‑panel display and keypad for local configuration and monitoring, and supports Modbus communication for remote supervision. The BE1-851 is housed in a rugged enclosure suitable for panel mounting in substations and generator control rooms.

Technical Specifications

• Model: BE1-851

• Protection functions: Phase overcurrent (51), ground overcurrent (51N)

• Current sensing: 1/5 A CT inputs

• Time‑current curves: Definite time, IEC, IEEE

• Pickup range: 0.05‑20.00 A (adjustable)

• Time dial: 0.05‑15.00 (adjustable)

• Accuracy: ±1% of pickup

• Output contacts: 2 form C (trip and alarm)

• Communication: Modbus RTU (RS‑485) optional

• Power supply: 48‑125 V AC/DC (wide range)

• Display: 2‑line LCD with keypad

• Event recording: 64 events, 20 fault records

• Operating temperature: -40°C to +70°C

• Certifications: CE, UL, RoHS

Functional Features

• Overcurrent protection: Phase and ground fault protection with multiple curve options.

• Programmable settings: Pickup and time delay can be adjusted for coordination.

• High accuracy: ±1% ensures reliable protection.

• Communication: Modbus enables remote monitoring.

• Event recording: Stores fault data for post‑fault analysis.

• Wide power supply: Accepts 48‑125 V AC/DC for flexible installation.

Typical Applications

• Generator backup protection: Phase and ground fault protection.

• Feeder protection: Overcurrent for distribution circuits.

• Transformer backup: Overcurrent protection for transformers.

• Motor protection: Overcurrent for large motors.

Installation and Configuration

Mount the BE1-851 on a panel. Connect the CT inputs, power supply, and output contacts. Configure the pickup values, time‑current curves, and communication settings using the front‑panel keypad. The relay includes a test mode for commissioning.

Compliance

Complies with IEEE C37.90, IEC 60255, CE and UL approved, RoHS compliant.

Conclusion

The Basler BE1-851 provides reliable, flexible overcurrent protection for generators and feeders, offering essential protection and communication features in a compact package.