ABB Relion 670 Series Technical Reference Manual page 464

Section 7
Current protection
458
• 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.
• In the current detection it is possible to use three different options: 1 out of 3
where it is sufficient to detect failure to open (high current) in one pole, 1 out of 4
where it is sufficient to detect failure to open (high current) in one pole or high
residual current and 2 out of 4 where at least two current (phase current and/or
residual current) shall be high for breaker failure detection.
• The current detection level for the residual current can be set different from the
setting of phase current detection.
• It is possible to have different back-up time delays for single-phase faults and for
multi-phase faults.
• 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 is high if the
circuit breaker is insufficient to clear faults, for example at low gas pressure.
BFI_3P
BFI_A
OR
BLOCK
ANSI09000976 V2 EN
Figure 227: Simplified logic scheme of the CCRBRF (50BF) starting logic
Pickup_PH
FunctionMode
1
Current and Contact
I_A
Pickup_BlkCont
52a_A
ANSI09000977 V1 EN
Figure 228: Simplified logic scheme of the CCRBRF (50BF), CB position evaluation
30 ms
AND
OR
Reset A
Retrip Time Out A
BackupTrip A
a
a>b
b
Current
OR
Contact
Time out A
OR
AND
BFP Started A
AND
a
a>b
OR
b
1MRK505222-UUS C
BFP Started A
150ms
S
SR
Q
AND
R
0
OR
ANSI09000976-2-en.vsd
AND Reset A
OR
AND
Current High A
OR
AND
AND
Contact Closed A
AND
ANSI09000977-1-en.vsd
Technical reference manual
Time out A
CB Closed A