• The retrip logic is inactive if the
CB fail retrip mode setting is set to "Off".
• If
CB fail retrip mode is set to the "Current check" mode, the activation of the
retrip output
TRRET
depends on the
CB failure mode setting.
- If
CB failure mode is set to the "Current" mode,
TRRET
is activated when
the value of any phase current exceeds the
Current value setting. The
TRRET
output remains active for the time set with the
Trip pulse time setting or until
all phase current values drop below the
Current value setting, whichever is
longer.
- If
CB failure mode is set to the "Breaker status" mode,
TRRET
is activated if
the circuit breaker is in the closed position. The
TRRET
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
CB failure mode is set to "Both",
TRRET
is activated when either of the
"Breaker status" or "Current" mode condition is satisfied.
• If
CB fail retrip mode is set to the "Without check" mode,
TRRET
is activated once
the timer 1 is activated without checking the current level. The
TRRET
output
remains active for a fixed time set with the
Trip pulse time setting.
The activation of the
BLOCK
input or the
CB_FAULT_AL
output deactivates the
TRRET
output.
POSCLOSE
I >
From Level detector 1
Timer 1 elapsed
From Timer 1
OR
AND
AND
CB fail retrip mode
”Without check”
CB fail retrip mode
”Current check”
CB failure mode ”Current”
CB failure mode ”Breaker
status”
CB failure mode ”Both”
AND
AND
AND
OR
OR
AND
TRRET
BLOCK
CB_FAULT_AL
From Timer 3
Figure 425: Retrip logic
Backup trip logic
The backup trip logic provides the
TRBU
output which can be used to trip the
upstream backup circuit breaker when the main circuit breaker fails to clear the
fault. The backup trip logic is activated by the timer 2 module or timer-enabling
signal from the start logic module (rising edge of the
START
input detected), and
simultaneously
CB_FAULT_AL
is active. The operation of the backup logic depends
on the
CB failure mode setting.
• If the
CB failure mode is set to "Current", the activation of
TRBU
depends on the
CB failure trip mode setting.
- If
CB failure trip mode is set to "1 out of 3", the failure detection is based on
any of the phase currents exceeding the
Current value setting. Once
TRBU
is
Protection related functions
1MRS757644 H
810
620 series
Technical Manual
