ABB RELION Series Technical Manual page 477

1MRS758755 A
REC615 and RER615
Technical Manual
remains active for the time set with the Trip pulse time setting or until the
values of all the phase currents or residual currents drop below the Current
value and Current value Res setting respectively, whichever takes longer.
• If CB failure trip mode is set to "2 out of 4", the failure detection requires
that a phase current and a residual current both exceed the Current value
and Current value Res setting respectively or two phase currents exceeding
the Current value. Once TRBU is activated, it remains active for the time set
with the Trip pulse time setting or until the values of all the phase currents
drop below the Current value, whichever takes longer.
In most applications, "1 out of 3" is sufficient.
• If the CB failure mode is set to "Breaker status", the TRBU output is activated if
the circuit breaker is in the closed position. Once activated, the TRBU output
remains active for the time set with the Trip pulse time setting or the time the
circuit breaker is in the closed position, whichever is longer.
• If the CB failure mode setting is set to "Both", TRBU is activated when the
"Breaker status" or "Current" mode conditions are satisfied.
The activation of the BLOCK input deactivates the TRBU output.
Protection related functions
Section 5
471