GE Multilin 745-W2-P5-G5-HI-A-R | SR745 Transformer Management Relay
Product Parameters
- Model Number: 745-W2-P5-G5-HI-A-R
- Series: Multilin 745 (SR745)
- Winding Configurations: W2 (Two-winding transformer support)
- Phase Current Inputs: P5 (5A Phase Current Secondary)
- Ground Current Inputs: G5 (5A Ground Current Secondary)
- Control Power: HI (High Voltage: 88–300 VDC / 70–265 VAC)
- Analog Inputs/Outputs: A (Included: 0–1 mA, 0–20 mA, or 4–20 mA)
- Rear Communication: R (RS485 Modbus RTU / Redundant RS485)
- Mounting: SR745-CASE (Draw-out case for easy maintenance)
Product Description
The GE Multilin 745 is a high-speed, multi-processor-based digital relay designed for the comprehensive protection and management of power transformers. The 745-W2-P5-G5-HI-A-R variant is specifically configured for two-winding transformers, providing advanced features like percent differential protection, overcurrent protection, and harmonic restraint to prevent nuisance tripping during transformer inrush. It includes sophisticated monitoring tools such as transformer loss-of-life tracking and event recording. The “Draw-out” case design (SR745-CASE) is a critical feature, allowing the relay internal unit to be removed for testing or replacement without disturbing the external wiring, ensuring minimal system downtime.
Application Fields
This relay is a standard choice for utility substations, large industrial power plants, and renewable energy sites (wind/solar farms). It is used to protect main power transformers, unit transformers, and distribution transformers from internal faults, overloads, and external system disturbances. Its integration capabilities make it ideal for SCADA environments where real-time monitoring of transformer health and loading is essential for grid reliability.
Product Specifications
- Weight: 8.50 kg (Including Case)
- Dimensions: 177 mm x 217 mm x 245 mm (4U height, half-rack width)
- Origin: Canada / USA
Operational Precautions
- CT Ratio Calibration: Ensure the Current Transformer (CT) ratios and connections (Star/Delta) are correctly programmed into the relay to account for phase shifts and magnitude differences across the transformer windings.
- Draw-out Safety: Before removing the relay from the SR745-CASE, ensure the CT shorting bars in the terminal block are functioning correctly to prevent open-circuiting energized CT secondaries.
- Control Voltage: Verify that the “HI” power supply matches your station battery or auxiliary AC voltage; using a low-voltage source on a “HI” rated unit will prevent the relay from booting.
- Thermal Modeling: Accurately input the transformer’s nameplate data (cooling type, ambient temp, and hot-spot limits) to ensure the Loss-of-Life and thermal protection features provide accurate alerts.
Recommended Similar Product Models
| Model Number | Series | Primary Function | Features |
|---|---|---|---|
| 745-W3-P5-G5-HI-A-R | SR745 | 3-Winding Protection | Supports Tertiary Windings |
| 735 | Multilin | Feeder Protection | Basic Overcurrent/Control |
| 845 | Multilin | Transformer Protection | Next-Gen / Color Display |
| 489 | Multilin | Generator Management | Specialized Protection |
| 750 | Multilin | Feeder Management | Detailed Logic / I/O |
