CHAPTER 4: SETPOINTS CONTROL889 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL 4–359• FlexLogic operand that reports on the operation of the portion of the scheme wherehigh-set or low-set current supervision is used• FlexLogic operand that reports on the operation of the portion of the scheme where52b status supervision is used only• FlexLogic operand that initiates tripping required to clear the faulted zone. TheBreaker Failure output can be sealed-in for an adjustable period• Target message indicating a failed breaker has been declared.Setup Path: Setpoints > Control > Breaker Failure > BF1(X) > BF1(X) SetupFUNCTIONRange: Disabled, Retrip, Latched Alarm, Alarm, ConfigurableDefault: DisabledWhen the Retrip function is selected and Breaker Failure is initiated (with re-trip currentsupervision), the output relay #1 “Trip” operates but the “ALARM” LED does not turn on.PH RETRIP SUPERV PICKUPRange: 0.050 to 30.000 x CT in steps of 0.001 x CTDefault: 1.000 x CTThe setpoint specifies the phase current Retrip level, which when exceeded after BreakerFailure initiation, will Retrip its own breaker. The setting is set to detect the lowestexpected fault current on the protected circuit.NTRL RETRIP SUPERV PICKUPRange: 0.050 to 30.000 x CT in steps of 0.001 x CTDefault: 1.000 x CTThis setpoint specifies the neutral current Retrip level, which when exceeded afterBreaker Failure initiation, will Retrip its own breaker. The setting detects the lowestexpected fault current on the protected circuit. Neutral Retrip current supervision is usedto provide increased sensitivity.SUPERVISIONRange: Current, 52b & Current, 52bDefault: CurrentThe setpoint specifies the type of supervision of the Breaker Failure element. There arethree options: current only, breaker status only, or both.BREAKER CLOSEDRange: Off, Any FlexLogic operandDefault: OffThe setpoint selects the FlexLogic operand (auxiliary switch contact) to indicate that thecircuit breaker is closed.T1 PICKUP DELAYRange: 0.000 to 6000.000 s in steps of 0.001 sDefault: 0.120 sThe setting provides a delay for Timer 1 logic which is supervised with currentsupervision only. The timer is set to the expected opening time of the circuit breaker, plusa safety margin intended to overcome the relay measurement and timing errors as wellas relay processing time and current supervision reset time. In a microprocessor relaythis time is not significant. In the 889 relay, the current magnitude ramps-down to zeroin ¾ of a power cycle after the current is interrupted.FASTPATH:In bulk oil circuit breakers, the interrupting time for currents less than 25% of theinterrupting rating can be significantly longer than the normal interrupting time.
