FANOX SIL B, User Manual

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Synchronism function (25) associated to recloser function (79)
If the parameter “Hold permission” of 79 function is prohibited any external condition will be considered
and 79 function will work normally without considering synchronism.
If “Hold permission” of 79 function is enable and it is associated with “ Permission of closure” of 25
function, could be occur:
1. If permissions LLLB, DLLB, LLDB y DLDB of 25 function are all prohibited, after tripping because of
a fault, circuit breaker never will be reclosed because
“Permission of closure” bit of 25 function will
never be activated. After time adjusted in hold time, 79 function will go to LOCKOUT status.
2. If permissions LLLB, DLLB, LLDB y DLDB of 25 function are all enable, it will be distinguished the
following cases:
a) If line, bar or both of them are dead, the circuit breaker will be always reclosed, because
“Permission of closure” only depends on corresponding permission adjustment, and it is not
necessary synchronism to get the circuit breaker reclose. .
b) If both, line and bar, are alive it will be necessary to get the reclose of the circuit breaker, not
only LLLB permission to be enable either to check synchronism. If LLLB permission is enable
but synchronism conditions do not verify the reclose will not occur and vice versa.