GE Multilin 745-W2-P5-G5-LO-A-R-E-H SR745-CASE TRANSFORMER MANAGEMENT RELAY

The GE Multilin 745 (745-W2-P5-G5-LO-A-R-E-H) is a premier transformer management relay designed to provide comprehensive protection, monitoring, and diagnostics for small, medium, and large power transformers. It is a critical component in substation automation, offering advanced features like differential protection, thermal modeling, and fault recording to ensure the longevity and reliability of power transformers. The “SR745-CASE” designates the draw-out unit enclosure, which facilitates easy testing and maintenance.

Technical Specifications

Parameter	Detail
Product Model	745-W2-P5-G5-LO-A-R-E-H
Series	Multilin 745 Transformer Management Relay
Manufacturer	GE / General Electric
Enclosure	SR745-CASE (Draw-out)
Input CTs	5A Phase / 5A Ground
Control Voltage	125/250V DC or 120/240V AC (LO – Low range option)
Protection Functions	Percent Differential (87), Thermal (49), Overcurrent (50/51)
Communication	RS232/RS485, Modbus protocol
Dimensions (Approx.)	225mm x 205mm x 325mm
Weight	6.5 kg
Country of Origin	Canada / USA

Application Fields

Power Substations: Primary protection for distribution and transmission transformers.
Industrial Facilities: Monitoring large step-down transformers for factory power distribution.
Renewable Energy: Protection of collector transformers in wind and solar farm substations.
Data Centers: Ensuring reliable power delivery by monitoring critical transformer health.

Usage Instructions

Installation: Slide the SR745-CASE into the panel cutout and secure it using the mounting hardware. Ensure the draw-out mechanism is fully locked to engage all rear terminal connections.
Wiring: Connect current transformer (CT) secondary inputs, voltage inputs, and control power according to the specific wiring diagram provided in the user manual. Warning: Always short-circuit CT inputs before disconnecting the relay to prevent high-voltage build-up.
Configuration: Use GE EnerVista 745 Setup software to configure the transformer’s vector group, CT ratios, and protection setpoints.
Maintenance: The draw-out design allows the relay to be pulled out for testing or replacement without disturbing permanent field wiring. Periodically download and analyze the event records to monitor transformer health.
Testing: Perform regular secondary injection testing using a relay test set to verify protection settings and output relay operations.

GE Multilin 745-W2-P5-G5-LO-A-R-E-H SR745-CASE TRANSFORMER MANAGEMENT RELAY

Frequently Asked Questions (Q&A)

Q: What does the “W2” suffix indicate?
- A: The W2 code refers to the specific hardware configuration regarding CT inputs and I/O options. It is essential to match this when replacing a unit to ensure it aligns with your secondary CT circuits.
Q: Can I access data remotely?
- A: Yes, via the RS485 communication ports, the 745 can be integrated into a SCADA system or accessed locally via a PC running EnerVista software.
Q: Is this relay compatible with older electromechanical relays?
- A: The 745 is designed to replace aging electromechanical differential relays while providing significantly higher precision and integrated monitoring capabilities.