Description

GE Multilin 745-W2-P5-G5-HI Transformer Protection Relay

The GE Multilin 745-W2-P5-G5-HI, also cataloged as the 745 Transformer Protection Relay, operates as a dedicated hardware component for two-winding transformer differential protection, monitoring, and control within transformer protection system platforms.

Hardware Specifications

Parameter	Specification
Model	745-W2-P5-G5-HI
Brand	GE Multilin
Weight	4.8 kg
Dimensions	9 in H x 7 1/8 in D x 7 in W
Operating Temp	-40 deg C to +60 deg C
Power Consumption	15 W typical, 35 W maximum
Series	745 Transformer Protection System
Product Type	Transformer Protection Relay
Control Power Supply	90-300 VDC / 70-265 VAC
Frequency	50 Hz / 60 Hz, tracking range 45 to 65 Hz
Phase Current Input	5 A secondary CT input
Ground Current Input	5 A secondary CT input
Voltage Relay Input	60 to 120 V
Current Burden	< 0.2 VA at 5 A
Thermal Continuous Rating	20 A continuous
Overcurrent Withstand	500 A for 1 second
Display	40 character LCD
Communication Ports	RS232, RS485, RS422
Communication Protocol	Modbus RTU / ASCII

Deterministic Network and Industrial Control Interface Characteristics

The GE Multilin 745 relay incorporates industrial communication functions for transformer monitoring and protection system integration. RS232 front panel communication provides local maintenance access, while rear RS485 and RS422 ports support Modbus RTU communication with supervisory control systems.

The relay processes transformer electrical measurements including phase current, ground current, frequency, harmonic content, loading condition, and thermal operating parameters. Event recording functions include oscillography, waveform capture, fault records, and operational logs for protection analysis.

The protection firmware executes transformer-specific algorithms including restrained differential protection (87T) with harmonic restraint/blocking, instantaneous differential overcurrent protection (87H), phase and ground overcurrent protection, negative sequence protection, thermal overload modeling, and volts-per-hertz overexcitation monitoring.

Frequently Asked Questions

Q: What current transformer inputs are supported by the 745-W2-P5-G5-HI configuration?
A: The P5 option provides 5 A phase current CT inputs and the G5 option provides 5 A ground current CT inputs for transformer protection measurement circuits.

Q: Does the relay support hot-swapping during energized operation?
A: The 745-W2-P5-G5-HI is designed as a panel-mounted protection relay. Hot-swap operation is not specified. Installation and replacement should be performed with the protection circuit isolated according to site procedures.

Q: What communication interfaces are available for integration?
A: The relay provides an RS232 front maintenance port and RS485/RS422 rear communication ports supporting Modbus RTU protocol.

Field Installation Guidelines

Install the relay in a suitable protective panel enclosure with controlled wiring separation between power circuits, CT measurement circuits, communication cables, and auxiliary control wiring.

Current transformer secondary wiring should use dedicated terminal connections with correct polarity verification before energization. CT circuits must not be opened while energized.

Communication wiring should maintain appropriate shielding and grounding practices. Shield termination should follow the plant grounding standard to reduce electrical noise coupling.

Provide adequate clearance for relay ventilation and service access. Verify control power polarity and voltage range before applying auxiliary supply.

Protection settings, CT ratios, transformer parameters, and trip output logic should be validated during commissioning using approved protection testing equipment.

Specifications

• Brand: General Electric

Advantages

• High reliability in industrial environments
• Supports continuous operation
• Compatible with major PLC/DCS systems