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CHAPTER 6: SETPOINTS
Breaker failure (50BF)
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
The Breaker Failure function monitors the phase currents, after a trip command from the
protection elements is initiated. If any phase current is above the set current level after the
BF DELAY time expires, a breaker failure will be declared, and will operate the selected
output relays. The Breaker failure scheme provides also an external input to initiate
breaker failure via Contact Input, Virtual Input, Remote Input, or Logic Element.
The following path is available using the keypad. For instructions on how to use the
keypad, please refer to Chapter 3 - Working with the Keypad.
PATH:
SETPOINTS > S4 CONTROLS > BREAKER FAIL
BF FUNCTION
Range: Disabled, Alarm, Latched Alarm
Default: Disabled
For details see
Common
BF CURRENT
Range: 0.05 to 20.00 x CT in steps of 0.01
Default: 1.00 x CT
This setting selects the current level to be monitored by the BF logic, after the
programmed time delays.
BF EXT INITIATE
Range: Off, Contact Input 1 to 10, Virtual Input 1 to 32, Remote Input 1 to 32, Logic
Element 1 to 16, CT Fail Alarm PKP, CT Fail Alarm OP, 2nd Harmonic Alarm, 2nd Harmonic
Default: Off
This setting allows the user to select Contact Input, Virtual or Remote Input, Logic
Element to initiate the Breaker Failure logic.
BF TIME DELAY 1
Range: 0.03 to 1.00 s in steps of 0.01 s
Default: 0.10 s
This timer starts when breaker trip command is issued from any of the protection
elements.
BF TIME DELAY 2
Range: 0.00 to 1.00 s in steps of 0.01 s
Default: 0.00 s
This timer does not start until a trip condition is recognized, BF TIMER DELAY 1 has
expired, and at least one of the phase currents is above the BF CURRENT setting.
OUTPUT RELAY X
For details see
Common
setpoints.
setpoints.
S4 CONTROLS
6–135
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