The BE1-87T Transformer Differential Relay is designed as primary protection for
power transformers against internal faults. Available in either single- or three-phase
configurations, this solid-state relay compares the currents entering and leaving the
protected transformer. If any imbalance is detected that is not attributable to other
(tested) factors, the relay provides a contact closure to isolate the power transformer to limit damage.
FEATURES• Single- and three-phase configurations.
• Input isolation.
• Three-phase configuration includes internal phase shift compensation
with zero-sequence current blocking.
• 2nd- and 5th-harmonic restraint.
• Adjustable through-current restraint.
• % IOP display.
• Tap scaling covers the range of 2.0 to 8.9 amperes in 0.1-ampere
increments in 5 Ampere CT models, and 0.4 to 1.78 amperes in
0.02 ampere increments in 1 Ampere CT models.
• Low sensing burden.
• Maintains proper operation when tested for interference in accordance with
IECC C37.90-1989, Trial-Use Standard Withstand Capability of Relay systems
to Radiated electromagnetic Interference from Transceivers.
• UL listed (except for 250Vdc power supply).
• Five year warranty