Products Multi Function Protection Relays

T-PRO Transformer Protection Relays

T-PRO 4000 Transformer Protection Relay
T-PRO 4000 Transformer Protection Relay
T-PRO 4500 Transformer Protection Relay

T-PRO 4500 Transformer Protection Relay

The IEC 61850 station bus embedded T-PRO relay provides complete 3-phase multi-winding transformer fault and overload protection, DFR-quality fault oscillography, sequence of event logging, trend recording, in a fully integrated protective relay solution, with advanced communications in a flexible cost-effective package.

The T-PRO comes in two models with different builds to suit specific market requirements. Model 4000 is a 3U or 4U 19 inch rack model whereas model 4500 is in an E12 case size and has dual rated 1A and 5A CT inputs. Model 4500 also has optional PRP redundancy communications. The user software is common to the two models.


  • High speed protection and complete control of multi-winding transformers with HV and LV windings connected to all bus types such as ring bus or breaker-and-half arrangements
  • Primary and backup protection of small, medium and large power transformers and reactors (including differential, ground differential, phase, neutral and ground overcurrent, phase under voltage, neutral overvoltage, under- and over-frequency, and over excitation)

Features and Benefits

  • Through Fault Monitoring function to measure the duration, peak and RMS current and accumulated I2t values for each phase during through fault
  • Internal magnitude and phase shift compensation, eliminating requirements for external CT connections and auxiliary CTs
  • 2nd and 5th harmonic restraint algorithm that improves security for energization, inrush and over fluxing.
  • High quality fault recording and event log

Flexible Communications

  • State-of-the-art communications to accommodate the industry’s latest network-based communications)
  • Ethernet ports with 2 unique MAC addresses that easily accommodate network access security needs

Substation Automation

  • IEC 61850 Station Bus on dedicated Optical/Copper Ethernet Ports included at no extra cost
  • Optional PRP (IEC 62439-3) communication redundancy in model 4500
  • Enhanced DNP3.0 Level 2 SCADA communication protocol including user-selectable point lists, class support and multiple master station support

Easy to Use

  • Flexible programmable logic for building customized schemes with ProLogic™ statements – 24 control logic statements (total of 192 statements)
  • User-friendly, Windows®-based relay setting and record analysis software

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