Basler BE1-BPR, Instruction Manual

Page: 30 / 148

2-16 BE1-BPR Application
Breaker Failure Logic 3 For Standard Relays (BFL3)
BFL3 logic provides the following application features:
1. Three-Pole Tripping BF Logic (Features: Input/output latch-in provided and Control timer limits
operational window). Three BFI inputs are available at IN3, IN4, and IN5 to start delay timer T1. If the
BFI inputs are not reset by the time timer 1 times out and either the phase (F1) or neutral fault detector
(F2) is picked up, then BFO1-3 closes (OUT1-3), tripping the backup breakers. A control timer (T3) is
used to limit the breaker failure window of opportunity and latch-in the BFI inputs. Refer to the breaker
failure timing diagram in Section 1 for information on setting the delay and control timers.
2. Single-Pole Tripping BF Logic (Features: Input/Output latch-in provided and Control timer limits
operational window). If single-pole tripping is used, two additional BFI inputs are available (IN6 and IN7)
to start delay timer T2. These inputs are only supervised by the phase fault detector (F1). If the BFI (IN6
and IN7) inputs are not reset by the time the timer T2 times out and the phase fault detector (F1) is still
picked up, the BFO outputs (OUT1-3) will close, tripping the backup breakers. Control timer, T3 is used
to limit the breaker failure window of opportunity. Refer to the breaker failure timing diagram in Section
1 for information on setting the delay and control timers.
Neutral fault detector (F2) is not used to supervise the single-pole BF logic because F2 is still picked up
by the phase imbalance after the fault clears. Three-phase BF logic is inhibited during this period
because there is no 3-phase BFI input active. For single-pole tripping, the phase pickup (PU1) must be
set above maximum load levels.