Beckwith M‑3425 Integrated Generator Protection Relay

The Beckwith M‑3425 is a microprocessor‑based integrated generator protection relay that provides comprehensive protection, control, and monitoring for synchronous generators. It integrates multiple protection elements—including differential (ANSI 87G), overcurrent (ANSI 51/50), over/undervoltage (ANSI 59/27), over/underfrequency (ANSI 81), reverse power (ANSI 32), loss‑of‑excitation (ANSI 40), volts‑per‑hertz (ANSI 24), and negative sequence (ANSI 46)—into a single compact unit. The M‑3425 is designed for utility, industrial, and marine generator protection applications, offering high accuracy and flexible configuration.

Protection Elements

Each protection element is independently programmable with adjustable pickup levels, time delays, and characteristic curves. The relay supports both definite‑time and inverse‑time characteristics, allowing flexible coordination with other protection devices. It includes a power system stabilizer (PSS) function and synchronism check capabilities.

User Interface and Communication

A front‑panel LCD display shows measured parameters, settings, and event logs. A keypad allows local programming. Communication ports include RS‑232, RS‑485, and optional Ethernet, supporting Modbus RTU, Modbus TCP, and DNP3 protocols.

Technical Specifications

Voltage input: 100‑480 VAC, 50/60 Hz, three‑phase. Current input: 1 A or 5 A secondary (CT). Accuracy: ±0.5% for voltage/current. Output contacts: 4 Form C, rated 5 A at 250 VAC. Power supply: 24‑250 VDC or 120‑240 VAC. Operating temperature: –30°C to +70°C. Complies with IEEE C37.90 and IEC 60255.

Applications

The M‑3425 is used for protection of synchronous generators in utility power plants, industrial cogeneration, and marine power systems.

Installation and Commissioning

Mount the relay in a standard panel cutout. Connect voltage, current, and control power inputs. Commissioning involves programming protection elements and performing secondary injection tests.

Reliability and Quality

Beckwith’s M‑3425 is built with industrial‑grade components and tested for environmental resilience.

Conclusion

The Beckwith M‑3425 integrated generator protection relay offers comprehensive, accurate protection for synchronous generators.