Basler Electric BE1‑87G Solid State Protective Relay

The Basler Electric BE1‑87G is a solid‑state differential relay specifically designed for generator protection. It provides high‑speed, selective protection against internal phase‑to‑phase and phase‑to‑ground faults by comparing the currents entering and leaving the generator windings. The relay operates on a percentage differential principle with a stabilising resistor to prevent maloperation during external faults.

This relay is a critical component for large synchronous generators, offering fast clearing times to minimise damage and maintain system stability. Its solid‑state design ensures high reliability and immunity to harmonics and DC offsets.

Key Features

• Percentage differential protection with adjustable slope

• Pickup current: 10–50% of rated CT secondary

• Stabilising resistor for through‑fault stability

• Operating time: < 30 ms at 2x pickup

• Low burden CT inputs

• Target and seal‑in relay for trip indication

• Compact panel‑mount case

Technical Specifications

Input: 1A or 5A CT secondary; pickup range: 0.1–2 A; stabilising resistor: 0–1000 Ω; output contacts: 2 x SPDT, 5 A; operating temperature: -10°C to +55°C; power supply: 125 VDC or 240 VAC optional.

Applications

Used for primary protection of synchronous generators in power plants, industrial co‑generation, and marine installations. The relay is also applicable to large motors and transformers with appropriate CT connections.

Installation and Calibration

Mount the relay on a standard panel. Connect the CTs from both line and neutral sides. Set the pickup current and slope via the front‑panel switches. Adjust the stabilising resistor based on generator parameters. Test points are provided for verification.

Reliability and Maintenance

The solid‑state construction provides long life with no moving parts. The relay is equipped with surge suppression and is resistant to electromagnetic interference. Periodic secondary injection testing is recommended.

Why Choose the BE1‑87G?

This relay is a trusted solution for generator differential protection, combining high speed with ease of setting. Basler Electric’s experience ensures a reliable product that meets the demands of critical power generation.

In conclusion, the Basler Electric BE1‑87G offers fast and accurate differential protection, safeguarding generators from internal faults.