ABB RELION REX640, Technical Manual, Page: 1169 / 1960

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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(OR)”
AND
AND
AND
OR
OR
AND
TRRET
BLOCK
CB_FAULT_AL
From Timer 3
AND
AND
CB failure mode ”Both(AND)”
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
CB failure mode and CB
failure trip mode as shown in Table 1115
.
Table 1115: Backup trip logic operation
Value of setting CB
failure mode Value of setting CB
failure trip mode Conditions for activating Backup trip logic
Current 1 out of 3 Any phase current exceeds
Current value
set-
ting.
1 out of 4 Either of the following is true:
• Any phase current exceeds
Current value
setting.
• The residual current exceeds
Current val-
ue Res
setting.
2 out of 4 Either of the following is true:
• Any phase current exceeds
Current value
setting and the residual current exceeds
Current value Res
setting.
Table continues on the next page
1MRS759142 F Protection related functions
REX640
Technical Manual
1169