BE1-87T, Transformer Differential Relay

These relays provide accurate and reliable percentage-differential protection for power transformers against internal faults.


  • Easily meet system requirements with single- or three-phase input configurations.
  • Simplified wiring for three-phase configuration includes internal phase-shift compensation with zero-sequence current blocking.
  • Excellent security using second- and fifth-harmonic restraint and adjustable through-current restraint.
  • Accurate, repeatable, and reliable operation.
  • Minimized CT costs as a result of low sensing burden.
  • Reduced battery load with low burden power supply.
  • LED targets provide clear annunciation of status.
  • Easily perform in-case system and device tests using test paddles.


Technical Resources