Warning: If the calculated time to trip factor is below the settingWarning a warning signal isactivated. The setting is given in minutes.7.9 Breaker failure protection CCRBRF(50BF) IP14514-1 v67.9.1 IdentificationM14878-1 v5Function description IEC 61850identificationIEC 60617identificationANSI/IEEE C37.2device numberBreaker failure protection, 3-phaseactivation and outputCCRBRF3I>BFSYMBOL-U V1 EN-US50BF7.9.2 Application M13916-3 v6In the design of the fault clearance system the N-1 criterion is often used. This means that a faultneeds to be cleared even if any component in the fault clearance system is faulty. One necessarycomponent in the fault clearance system is the circuit breaker. It is from practical and economicalreason not feasible to duplicate the circuit breaker for the protected component. Instead abreaker failure protection is used.Breaker failure protection, 3-phase activation and output (CCRBRF, 50BF) will issue a back-up tripcommand to adjacent circuit breakers in case of failure to trip of the “normal” circuit breaker forthe protected component. The detection of failure to break the current through the breaker ismade by means of current measurement or as detection of remaining trip signal (unconditional).CCRBRF (50BF) can also give a re-trip. This means that a second trip signal is sent to the protectedcircuit breaker. The re-trip function can be used to increase the probability of operation of thebreaker, or it can be used to avoid back-up trip of many breakers in case of mistakes during relaymaintenance and test.7.9.3 Setting guidelines M11546-4 v8.1.1The parameters for Breaker failure protection 3-phase activation and output CCRBRF (50BF) areset via the local HMI or PCM600.The following settings can be done for the breaker failure protection.GlobalBaseSel: Selects the global base value group used by the function to define (IBase), (VBase)and (SBase).Operation:Disabled/EnabledFunctionMode This parameter can be setCurrent orContact. This states the way the detection offailure of the breaker is performed. In the mode current the current measurement is used for thedetection. In the modeContact the long duration of breaker position signal is used as indicator offailure of the breaker. The modeCurrent&Contact means that both ways of detections are1MRK 511 358-UUS A Section 7Current protection169Application manual
