GE SR745-W2-P5-G5-HI
GE SR745-W2-P5-G5-HI - Image 2

GE SR745-W2-P5-G5-HI

Product Introduction: The GE SR745-W2-P5-G5-HI is a Transformer Protection Relay from the GE Multilin 745 series. It is a high-speed, multiprocessor-based transformer management relay for two-winding or three-winding transformers. The ordering code indicates: W2 (two-winding transformer), P5 (5 A phase CT secondary), G5 (5 A ground CT secondary), HI (high control power 90–300 V DC / 70–265 V AC). The relay combines percentage differential, overcurrent, frequency, and overexcitation protection with individual harmonic and total harmonic distortion (THD) monitoring.

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Category: SKU: GE SR745-W2-P5-G5-HI

Description

GE SR745-W2-P5-G5-HI

Technical Specifications:

  • Series: GE Multilin 745 Transformer Protection System
  • Transformer Winding Configuration: W2 = two-winding
  • Phase CT Secondary: 5 A (P5), 5 A per winding
  • Ground CT Secondary: 5 A (G5)
  • Control Power: HI = 90–300 V DC, 70–265 V AC, 48–62 Hz
  • Operating Temperature: -40 °C to +60 °C (-40 °F to +140 °F)
  • Storage Temperature: -40 °C to +80 °C (-40 °F to +176 °F)
  • Humidity: Up to 90% non-condensing
  • Weight: Approximately 4.8–8.4 kg (per variant sources)
  • Construction: Drawout relay and matching enclosure (SR series)
  • Front Panel: 40-character LCD, status LEDs, control keys, numeric keypad, RS-232 programming port
  • Communication: RS-232 (front panel), RS-485/RS-422 (rear panel)
  • Logic Inputs: 16 logic inputs
  • Analog Outputs: 5 × 4–20 mA
  • Relay Outputs: 2 × Form A
  • Protection Rating: IP40 (front panel)

Functional Features:

  • Percentage differential protection with adaptive harmonic restraint (2nd and 5th harmonics) for inrush and overexcitation security
  • Adaptive time-overcurrent elements that adapt to transformer loading harmonic content
  • Multiple setpoint groups (up to 4) for dynamic protection requirements
  • Dynamic CT ratio mismatch correction by monitoring tap changer position
  • Overexcitation blocking and protection
  • Over/under-frequency protection
  • Restricted earth fault (REF) protection
  • System overload protection
  • FlexLogic™ programmable logic for customized protection and control schemes
  • Individual harmonic and total harmonic distortion (THD) monitoring
  • Waveform capture and playback for fault analysis
  • Automatic configuration eliminates special CT connection requirements (all CTs wye-connected)
  • 16 logic inputs and rear expansion port for high configurability
  • EnerVista 745 software for setup and monitoring

Application Scenarios:

  • Power transformer protection in substations (small, medium, and large transformers)
  • Industrial plant transformer protection
  • Utility transmission and distribution substations
  • Autotransformer protection
  • Generator step-up transformer protection
  • Steel, petrochemical, paper, and metallurgical industry transformer installations

Performance Parameters:

  • High-speed operation for rapid transformer fault detection and response
  • Adaptive harmonic restraint ensures security during inrush and overexcitation
  • Comprehensive metering: current, voltage, power, harmonics, THD
  • Multiple setpoint groups for dynamic protection adaptation
  • Waveform capture and playback capability for post-fault analysis
  • Operating temperature range -40 °C to +60 °C for harsh environments

Material and Structural Characteristics:

  • Drawout relay case with matching enclosure (SR series construction)
  • Industrial-grade PCB with multiprocessor architecture
  • Front panel with 40-character LCD, status LEDs, control keys, numeric keypad, RS-232 port
  • Rear panel with RS-485/RS-422 port and 16 logic inputs
  • Rear terminal blocks for CT, VT, control power, analog outputs, and relay outputs
  • Robust construction for long-term performance in industrial environments

Working Principle: The relay continuously samples phase currents from both windings (5 A CT secondaries) and ground fault currents. The multiprocessor architecture executes percentage differential protection algorithms, comparing the currents entering and exiting the transformer while compensating for CT ratio mismatch (including dynamic correction based on tap changer position). Adaptive harmonic restraint uses 2nd harmonic (inrush) and 5th harmonic (overexcitation) content to block differential operation during transient conditions. Overcurrent, over/under-frequency, restricted earth fault, and overexcitation protection elements operate independently. FlexLogic™ programmable logic allows users to customize protection and control schemes. Waveform capture records fault events for playback and analysis. Installation Requirements:

  • Install in a protection relay panel using the SR drawout case, standalone or rack-mounted with other SR series relays
  • Connect 5 A phase CTs from both windings (wye-connected), ground CTs, and VTs per schematics
  • Wire control power (90–300 V DC or 70–265 V AC)
  • Connect RS-232 (front) for local setup or RS-485/RS-422 (rear) for multi-relay monitoring
  • Configure setpoints using EnerVista 745 Setup software
  • Verify drawout mechanism engagement

Usage Notes:

  • All CTs must be wye-connected; the relay auto-configures for various CT connections
  • Configure setpoint groups for different operating conditions (e.g., normal, emergency, maintenance)
  • Use FlexLogic™ to customize protection and control schemes per application requirements
  • Monitor individual harmonic and THD values for transformer health assessment
  • Use waveform capture and playback for post-fault analysis and protection testing
  • Periodically test protection functions using relay test equipment
  • For multi-relay installations, use the rear RS-485/RS-422 port for networked monitoring

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