GE SR745-W3-P5-G5-HI – Advanced Transformer Protection Relay

Overview

The GE SR745-W3-P5-G5-HI is an intelligent transformer protection relay belonging to the Multilin SR Series by GE Grid Solutions. Designed for comprehensive protection, control, and monitoring of power transformers, it ensures reliable operation of electrical substations and power distribution networks.
Featuring advanced microprocessor-based technology, the SR745 provides complete transformer protection including differential, overcurrent, voltage, frequency, and thermal protection functions. It also supports extensive communications and event recording, making it a cornerstone for modern smart grid applications.

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Applications

The SR745 is widely used in:

• Power Utilities and Substations – for real-time transformer protection and control.

• Industrial Power Systems – safeguarding large power transformers in process industries.

• Renewable Energy Installations – protecting step-up transformers in wind and solar farms.

• Oil & Gas Facilities – ensuring system reliability in critical power distribution networks.

• Commercial Complexes and Data Centers – maintaining transformer safety and uptime.

  
  

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Structure & Functionality

The SR745 relay integrates multiple protection, control, and monitoring functions in a single compact unit. It employs differential protection algorithms for detecting internal transformer faults, harmonic restraint for inrush current discrimination, and thermal modeling for overload protection.
Its modular design includes:

• Front Control Panel with LCD display and keypad

• Digital and Analog I/O for control and alarm signaling

• Communication Ports for integration with SCADA or DCS systems

• Non-volatile Memory for event and disturbance recording

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Key Features

• Comprehensive Transformer Protection: Differential, overcurrent, overvoltage, and thermal functions.

• Advanced Harmonic Restraint: Prevents false trips during magnetizing inrush or overexcitation.

• Built-in Fault and Event Recorder: Captures up to 512 events with precise time-stamping.

• Multiple Communication Protocols: Supports Modbus RTU/TCP, DNP3, IEC 61850, and GE Modbus.

• User-Friendly Interface: LCD screen with intuitive menu navigation for setup and diagnostics.

• Self-Diagnostics and Health Monitoring: Ensures continuous reliability and early fault detection.

• Programmable Logic (FlexLogic™): Allows user-defined automation without external PLCs.

  
  

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Technical Specifications

Manufacturer: GE Grid Solutions
Model: SR745-W3-P5-G5-HI
Type: Transformer Protection Relay
Protection Functions: Differential, Overcurrent, Thermal, Over/Undervoltage, Frequency
Rated Current: 1A / 5A CT Nominal (Configurable)
Rated Voltage: 100–250 V AC/DC
Frequency Range: 50/60 Hz
Display: Graphical LCD with LED status indicators
Communication Ports: RS485, Ethernet (TCP/IP), and USB
Protocols: Modbus, DNP3, IEC 61850
Event Recording: Up to 512 events, 64 disturbance records
Mounting: Panel-mounted
Operating Temperature: -40°C to +60°C
Compliance: IEC, ANSI, and IEEE standards

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Installation & Maintenance

1. Mounting: Install the relay in a clean, dry, and vibration-free environment on a standard 19-inch panel.

2. Wiring: Connect CTs, PTs, trip circuits, and communication lines according to GE’s installation manual.

3. Configuration: Use EnerVista SR Setup Software for easy relay configuration and parameter tuning.

4. Testing: Perform functional and trip tests before energizing the transformer.

5. Maintenance: Minimal—only periodic inspection, firmware updates, and verification of communication integrity are required.

   
   

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Advantages

• High-speed fault detection and isolation

• Enhanced system reliability with redundant communication options

• Flexible configuration for two- or three-winding transformers

• Comprehensive monitoring and event analysis tools

• Backed by GE’s proven reliability and global technical support

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Conclusion

The GE SR745-W3-P5-G5-HI stands as a premium transformer protection relay, combining advanced algorithms, intelligent diagnostics, and robust communication capabilities in a single device. Engineered for performance and longevity, it ensures reliable operation of transformers in critical power systems while simplifying integration with modern SCADA and IEC 61850 networks.
With its versatility and proven dependability, the SR745 is an ideal choice for utilities and industries seeking smart, scalable, and high-performance transformer protection.