ABB REG670 - Page 417

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.
S
R
SR
Q
OR
AND
AND
30 ms
t
150 ms
START
STL1
OR
OR
BackupTrip L1
BFP Started L1
Time out L1
Reset L1
BLOCK
Retrip Time Out L1
IEC09000976-1-en.vsd
IEC09000976 V1 EN
Figure 185: Simplified logic scheme of the CCRBRF starting logic
AND
AND
AND
AND
AND
OR
OR
OR
a
b
a>b
AND
a
b
a>b
I>BlkCont
AND
Time out L1
BFP Started L1
Reset L1
CBCLDL1
IL1
Current High L1
Contact Closed L1
IEC09000977-1-en.vsd
FunctionMode
OR
OR
Current
Contact
Current and Contact
1
IP>
CB Closed L1
IEC09000977 V1 EN
Figure 186: Simplified logic scheme of the CCRBRF, CB position evaluation
1MRK502052-UEN B Section 8
Current protection
411
Technical manual