ABB RELION REX640 Technical Manual page 1169

1MRS759142 F
Timer 1 elapsed
From Level detector 1
POSCLOSE
CB_FAULT_AL
Figure 663: Retrip logic
Backup trip logic
Timer 2 activates Backup trip logic, which gives a backup trip TRBU for the upstream
circuit breaker if the main circuit breaker fails to clear the fault. Backup trip logic is
also activated if the timer-enabling signal from the Start logic module (rising edge
of the START input detected) and CB_FAULT_AL are both active.
The operation of Backup trip logic depends on the settings
failure trip mode as shown in
Table 1115: Backup trip logic operation
Value of setting CB
failure mode
Current
Table continues on the next page
REX640
Technical Manual
From Timer 1
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(OR)"
I >
OR
AND
CB failure mode "Both(AND)"
From Timer 3
BLOCK
Value of setting CB
failure trip mode
1 out of 3
1 out of 4
2 out of 4
AND
AND
AND
AND
OR
AND
AND
Table 1115
.
Conditions for activating Backup trip logic
Any phase current exceeds
ting.
Either of the following is true:
• Any phase current exceeds
setting.
• The residual current exceeds
ue Res setting.
Either of the following is true:
• Any phase current exceeds
setting and the residual current exceeds
Current value Res setting.
Protection related functions
OR
TRRET
AND
CB failure mode and CB
Current value set-
Current value
Current val-
Current value
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