Basler BE1-87G Generator Differential Relay

The Basler BE1-87G (model G1EA1LA0N1P, part number 9 1708 18 100) is a high-speed, solid-state differential relay specifically designed for the protection of large synchronous generators. This relay provides rapid detection and clearing of internal faults such as phase-to-phase short circuits and turn-to-turn faults, preventing catastrophic damage to the generator. It is widely used in utility and industrial power plants for reliable generator protection.

The BE1-87G features advanced percentage restraint and harmonic restraint techniques to prevent maloperation during external faults and generator start-up. The relay includes a reactor (in some configurations) for additional stability and filtering. It offers adjustable settings for pickup, slope, and time delay, allowing precise coordination with the generator's characteristics.

Technical Specifications

• Model: BE1-87G (G1EA1LA0N1P)

• Protection type: Percentage differential (87G)

• Current sensing: 1/5 A CT inputs

• Pickup range: 0.05-2.00 A (adjustable)

• Slope setting: 0-40% (adjustable)

• Harmonic restraint: Second harmonic (15-30%)

• Response time: < 20 ms (typical)

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

• Power supply: 24-240 V AC/DC (universal)

• LED indicators: Power, pickup, trip

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

• Dimensions: 200 x 150 x 80 mm

• Certifications: CE, UL, RoHS

Functional Features

• Percentage differential protection: Provides sensitive fault detection while maintaining stability for external faults.

• Harmonic restraint: Blocks tripping during generator start-up and overexcitation conditions.

• Fast operation: Trip times less than one cycle for rapid fault clearing.

• Adjustable settings: Pickup, slope, and harmonic restraint can be field-adjusted.

• Reactor option: Additional filtering and stability for improved performance in noisy environments.

Typical Applications

• Large synchronous generators: Protection of steam, gas, and hydro generators.

• Unit-connected generators: Differential protection for generator-transformer units.

• Industrial generators: Protection of critical power generation assets.

Installation and Configuration

Mount the BE1-87G on a panel. Connect the CT inputs from the generator neutral and line sides, the power supply, and output contacts. Configure the pickup, slope, and harmonic restraint settings using the front-panel controls. The relay includes test points for verification and a test mode for commissioning.

Compliance

Complies with IEEE C37.91, IEC 60255, CE and UL approved, RoHS compliant.

Conclusion

The Basler BE1-87G provides reliable, high-speed differential protection for large generators, ensuring rapid fault clearing and minimizing damage to critical equipment.