ABB Relion 670 Series Technical Reference Manual page 189

1MRK 505 208-UEN B
Technical reference manual
• The minimum length of the re-trip pulse, the back-up trip pulse and the back-
up trip pulse 2 are settable. The re-trip pulse, the back-up trip pulse and the back-
up trip pulse 2 will however sustain as long as there is an indication of closed
breaker.
• The back-up trip can be made without current check. It is possible to have this
option activated for small load currents only.
• It is possible to have instantaneous back-up trip function if a signal (CBFLT)
is high due to that circuit breaker is unable to clear faults, for example at low
gas pressure.
Current
BLOCK
STIL1
START
CBCLD
IEC06000150 V1 EN
Figure 84: Simplified logic diagram of the retrip function
Internal logical signal STIL1 has logical value 1 when current in that phase has
magnitude larger than setting parameter IP>.
Current
I>
AND
START
CBCLD
CBAlarm
CBFLT
t
IEC06000156 V1 EN
Figure 85: Simplified logic diagram of the back-up trip function
AND
Current &
Contact
AND
OR
AND
AND
Contact
AND
Current &
Contact
AND OR
OR
AND
Contact
AND
Section 6
Current protection
t1 tp
t
AND OR
t2
t
t3
OR
t
TRRET
en06000150.vsd
tp
TRBU
tp
TRBU2
CBALARM
en06000156.vsd
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