ABB 615 series Technical Manual page 785

1MAC059074-MB A
615 series ANSI
Technical Manual
until the values of all the phase currents drop below the Current value setting,
whichever takes longer.
• If CB failure trip mode is set to "1 out of 4", the failure detection is based on
either a phase current or a residual current exceeding the Current value or
Current value Res setting respectively. 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 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
779