through the breaker is made by means of current measurement or as detection of remainingtrip signal (unconditional).CCRBRF (50BF) can also give a re-trip. This means that a second trip signal is sent to theprotected circuit breaker. The re-trip function can be used to increase the probability ofoperation of the breaker, or it can be used to avoid back-up trip of many breakers in caseof mistakes during relay maintenance and test.7.10.3 Setting guidelinesThe parameters for Breaker failure protection 3-phase activation and output CCRBRF(50BF) are set 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 set Current or Contact. This states the way thedetection of failure of the breaker is performed. In the mode current the currentmeasurement is used for the detection. In the mode Contact the long duration of breakerposition signal is used as indicator of failure of the breaker. The mode Current&Contactmeans that both ways of detections are activated. Contact mode can be usable inapplications where the fault current through the circuit breaker is small. This can be thecase for some generator protection application (for example reverse power protection) orin case of line ends with weak end infeed.RetripMode: This setting states how the re-trip function shall operate. Retrip Off meansthat the re-trip function is not activated. CB Pos Check (circuit breaker position check) andCurrent means that a phase current must be larger than the operate level to allow re-trip.CB Pos Check (circuit breaker position check) and Contact means re-trip is done whencircuit breaker is closed (breaker position is used). No CBPos Check means re-trip is donewithout check of breaker position.Section 7 1MRK 506 334-UUS ACurrent protection230Application manual
