Basler Electric BE1-11g - Manual (Page 18)

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Vector Jump (78) Protection
One vector jump protection element protects the generator by disconnecting it from the grid when a loss
of mains or mains failure occurs, preventing the generator from remaining tied to the mains if the mains
returns due to an external reclose device.
Frequency (81) Protection
Eight independent frequency elements can be set for over, under, or rate of change (81R) frequency
operation. Each can be individually set to monitor the frequency on the main three-phase voltage input or
the Vx input. Rate of change can be set to operate on positive, negative, or “either”.
Note
BE1-11g protection systems enabled for IEC-61850 communication
(style Gxxxx5xxxxxxxx) 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 six 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
Seven 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
Time Curve Characteristics 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 individually set 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.
Phase Current Differential (87) Protection (style GxxxxxxxPxxxxx or GxxxxxxxTxxxxx)
One phase current differential element provides three-phase, percentage-restrained, differential
protection with dual-slope, in-phase, differential mode. In flux balance mode, the differential CTs are
connected in a flux balancing configuration.
Neutral Current Differential (87N) Protection (style GxxxxxxxPxxxxx or GxxxxxxxTxxxxx)
One neutral current differential element provides sensitive phase-to-ground fault differential protection for
the wye winding of the transformer.
Introduction BE1-11g