Beckwith Electric M‑520 Intertie Protection Relay

The Beckwith Electric M‑520 is a microprocessor‑based intertie protection relay designed to protect utility interconnections, tie lines, and distributed generation interconnections. It provides comprehensive protection and control functions including overcurrent, over/undervoltage, over/underfrequency, reverse power, and directional power protection. The M‑520 is suitable for utility, industrial, and renewable energy applications where interconnection protection is required.

Protection Elements

The relay integrates multiple protection elements including overcurrent (ANSI 50/51), over/undervoltage (ANSI 59/27), over/underfrequency (ANSI 81), reverse power (ANSI 32), and directional power (ANSI 67). Each element is independently programmable with adjustable settings. The relay also includes synchronism check functions for safe interconnection.

User Interface and Communication

A front‑panel LCD display and keypad allow 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. 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‑520 is used for protection of utility interconnections, distributed generation tie lines, and cogeneration interconnections.

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 Electric’s M‑520 is built with industrial‑grade components and tested for environmental resilience.

Conclusion

The Beckwith Electric M‑520 intertie protection relay provides comprehensive, reliable protection for utility interconnections and tie lines.