745 Transformer Management Relay

The 745 is a high speed, multiprocessor based, 3-phase, two or three winding, transformer management relay intended for the primary protection and management of small, medium and large power transformers.

New in SR745:

  • Fast, flexible and reliable communications - Embedded 10BaseT Ethernet capability provides faster data transfer thus improves system performance

  • Reduce installation & maintenance cost - Fewer components to install, commission and maintain

  • Simplified remote communication- Easy integration to Wide Area Network provides effortless remote access to the devices

  • Unique Security Audit Trail feature provides fast and easy troubleshooting, improved maintenance procedures and increased device security - Viewpoint Maintenance 3.0 can generate Security History Report from the 745 and clearly maps out detailed description of device configuration changes

  • Enhanced fault and disturbance analysis - Expanded (doubled) sequence of event recorder and waveform capture (256 time stamped events and up to 128 cycles of oscillography data at a sampling rate of 64 samples per power cycle)

  • Increased ease of use - New features have been added to 745 Setup Program to quickly and easily complete 745 commissioning, testing and maintenance tasks (see 745 release notes for details)


    • Features and Benefits


  • Unique Protection Features - Optimum transformer life expectancy, harmonic de-rating, advanced loss of life algorithm, THD monitoring, built-in winding adaptive overcurrent elements for backup protection

  • Best in class man machine interface (MMI) - Large backlit display with 40 characters to view relay information and settings in direct sunlight, full numerical keypad, and setpoint navigation keys

  • Accurate metering under sever system disturbances - Tracks power system frequency and adjusts sampling rate accordingly

  • Flexible and cost effective control for complex systems - Use FlexLogic™ to customize the functionality of your transformer protection & control system to address unique, site specific applications

  • Minimize replacement time - Draw-out construction

  • Improve uptime of auxiliary equipment - Through I/O monitoring

  • Reduce system event analyzing time and cost - Sequence of event reports, oscillography, data logging, IRIG-B time synchronization

  • Simplified testing - Built in simulation features and waveform playback for relay setting verification

  • Cost effective access to information - Via Modbus RTU and DNP 3.0 Level 2 protocols, through standard RS232, RS485 & RS422 serial ports, and optional Modbus RTU over TCP/IP through embedded Ethernet 10BaseT Port to connect to 10MB Ethernet local or wide area networks.

  • Advanced current monitoring - Current metering including phase & ground, demand, sequence components, differential and restraint, and ground differential

  • Industrially hardened - With optional harsh environment conformal coating when installed in chemically corrosive and humid environments


    • Applications


  • Primary protection and management of small, medium and larger power transformers

  • Up to 3 restraint windings


    • Protection and Control


  • Percent differential

  • Adaptive harmonic restraint

  • Multiple overcurrent elements

  • Adaptive time O/C elements

  • Underfrequency

  • Frequency rate-of-change

  • Overexcitation (V/Hz)

  • 4 setpoint groups

  • Restricted ground fault (optional)

  • 1 analog transducer input (optional)

  • 16 digital (logic) inputs

  • 7 analog transducer outputs (optional)

  • 9 control outputs


    • Monitoring and Metering


  • All currents

  • THD and harmonics

  • Demand

  • Harmonic analysis

  • Voltage

  • Calculated 3 Phase Power

  • Tap position

  • Ambient temperature

  • Analog transducer input

  • Event recorder

  • Oscillography & Data Logger

  • Oscillography playback


    • User Interface


  • Front Panel LEDs, full key pad, and backlit LCD display

  • Ethernet port, 10Mbps

  • RS232, RS485 and RS422 ports - up to 19,200 bps

  • Multiple protocols - ModBus™ RTU, ModBus™ TCP/IP, DNP 3.0 Level 2

  • Time synchronization via IRIG-B Port

  • Includes EnerVista software