Basler Electric BE1-11t User Manual
Page 18
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9424200995 Rev H
Note
BE1-11t protection systems enabled for IEC-61850 communication
(style Txxxx5xxxxxxxx) have their frequency protection elements fixed
at four underfrequency elements, two overfrequency elements, and
two frequency rate-of-change elements.
Instantaneous Overcurrent (50) Protection
Directional overcurrent protection is provided by nine instantaneous overcurrent elements. Digital signal
processing filters out unwanted harmonic components while providing fast overcurrent response with
limited transient overreach and overtravel.
Instantaneous overcurrent elements can be set for single-phase, three-phase, ground, neutral, positive-
sequence, negative-sequence, or unbalanced protection.
Breaker Failure (50BF) Protection
One breaker failure function provides protection and security for the power system against failure of the
monitored breaker.
Inverse Overcurrent (51) Protection
Nine inverse overcurrent elements can be set for single-phase, three-phase, ground, neutral, positive-
sequence, negative-sequence, or unbalanced protection. Inverse-overcurrent functions employ a dynamic
integrating timing algorithm covering a range from pickup to 40 times pickup with selectable
instantaneous or integrated reset characteristics. Inverse time overcurrent curves conform to IEEE Std
C37.112-1996 - IEEE Standard Inverse-Time Characteristic Equations for Overcurrent Relays, and
include seven curves similar to Westinghouse/ABB CO curves, five curves similar to GE IAC curves, a
fixed time curve, and a user programmable curve. Refer to the
chapter for
more information about the inverse overcurrent protection characteristic curves.
Phase inverse overcurrent elements can be voltage restrained or controlled for generator backup
applications. Negative-sequence current protection (46) is included as a mode of the 51 (inverse
overcurrent) element. Each inverse overcurrent element can be set separately for forward, reverse, or
non-directional control.
A separate ground current input provides ground overcurrent protection for a separate ground CT.
Optionally, an SEF (sensitive earth fault) version of the separate ground CT is available.
Note
BE1-11t protection systems enabled for IEC-61850 communication
(style Txxxx5xxxxxxxx) have their inverse overcurrent protection
elements fixed at nine inverse overcurrent elements without voltage
control.
Phase Current Differential (87) Protection
One phase current differential element provides three-phase, percentage-restrained, differential
protection with dual-slope.
Neutral Current Differential (87N) Protection
Two neutral current differential elements provides sensitive phase-to-ground fault differential protection
for the wye winding of the transformer.
Resistance Temperature Detector (49RTD) Protection
Fourteen resistance temperature detector elements provide over/undertemperature protection in
applications where a remote RTD module is connected to the BE1-11t via Ethernet or RS-485 cable. For
more information, refer to the
Introduction
BE1-11t