Description

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

Configured for transformer differential protection and current input processing in GE Multilin substation automation systems, the GE Multilin 745-W2-P5-G5-HI (745 Transformer Protection Relay) provides direct physical/electrical execution for 2-winding transformer protection circuits.

Hardware Specifications

Parameter	Specification
Model	GE Multilin 745-W2-P5-G5-HI
Brand	GE Multilin
Operating Temp	-40 deg C to +60 deg C
Power Consumption	25 W nominal, 45 W maximum
Protection Function	Transformer differential, overcurrent, ground fault, thermal overload monitoring
Transformer Configuration	2-winding transformer support
Phase CT Inputs	5 A nominal
Ground CT Inputs	5 A nominal
Frequency Tracking	50/60 Hz nominal, 40 to 70 Hz range
Power Supply Input	88 to 300 VDC / 88 to 265 VAC, 47 to 63 Hz
Communication Interface	RS232, RS485, RS422, Modbus RTU
Data Transfer Rate	Up to 19,200 bps
Mounting Type	Draw-out case, 19-inch rack mount or panel cutout mount

Deterministic Network and Protection Processing

The GE Multilin 745-W2-P5-G5-HI uses microprocessor-based protection processing for transformer electrical measurement and trip logic execution. The relay performs percent differential protection with harmonic restraint functions to discriminate transformer magnetizing inrush and overexcitation conditions. Digital CT ratio matching and phase vector compensation are executed internally, removing the requirement for external interposing CT devices.

The unit provides optically isolated digital inputs for external status monitoring and interlocking functions. Form-A and Form-C output relays provide direct interfaces for breaker trip and control circuits. Configurable 4-20 mA analog outputs support transmission of measured parameters including current values, thermal loading, and differential current information.

Firmware operation supports event recording, disturbance capture, waveform storage, and fault parameter logging for protection analysis. RS485/RS422 communication with Modbus RTU protocol enables connection to SCADA and substation automation networks.

Frequently Asked Questions

Q: Does the GE Multilin 745-W2-P5-G5-HI support direct CT ratio matching without external CTs?
A: Yes. The relay performs digital CT ratio matching and phase vector group compensation internally through software configuration.

Q: What type of field wiring replacement method is supported by this relay?
A: The relay uses a draw-out case construction, allowing relay module replacement without disturbing rear field wiring connections.

Q: What communication protocols are available for integration?
A: The unit provides RS232 front-panel communication and RS485/RS422 rear communication interfaces supporting Modbus RTU protocol.

Field Installation Guidelines

• Install the relay in a suitable rack or panel enclosure using the specified draw-out mounting arrangement.
• Maintain separation between CT wiring, control wiring, and high-energy power conductors to reduce electromagnetic interference.
• Connect CT secondary circuits using dedicated terminal wiring and verify polarity before energizing the protection system.
• Ground cable shields according to substation grounding practices, with shield termination arranged to minimize circulating currents.
• Verify auxiliary supply voltage compatibility before applying power to the HI power supply input.
• Confirm communication wiring polarity, termination, and addressing before connecting RS485/RS422 networks.
• Perform protection setting verification and input/output functional checks before placing the relay into service.

Specifications

• Brand: General Electric

Advantages

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