Operation Principle - ABB REL650 series Technical Manual

1MRK 506 335-UUS A
7.11.7
Technical manual

Operation principle

The Breaker failure protection, phase segregated activation and output (CSPRBRF 50BF)
is initiated from protection trip command, either from protection functions within the IED
or from external protection devices.
The initiate signal can be phase selective or general (for all three phases). Phase selective
initiate signals enable single pole re-trip function. This means that a second attempt to
open the breaker is done. The re-trip attempt can be made after a set time delay. For
transmission lines single pole trip and autoreclosing is often used. The re-trip function can
be phase selective if it is initiated from phase selective line protection. The re-trip function
can be done with or without current or contact check. With the current check the re-trip is
only performed if the current through the circuit breaker is larger than the operate current
level. With contact check the retrip is only performed if breaker is indicated as closed.
The initiate signal can be an internal or external protection trip signal. This signal will start
the back-up trip timer. If the opening of the breaker is successful this is detected by the
function, both by detection of low RMS current and by a special adapted algorithm. The
special algorithm enables a very fast detection of successful breaker opening that is, fast
resetting of the current measurement. If the current detection has not detected breaker
opening before the back-up timer has run its time a back-up trip is initiated.
Further, the following possibilities are available:
• 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.
• Back-up trip is always made with current or contact check. It is possible to have this
option activated for small load currents only.
BFI_3P
BFI_A
OR
BLOCK
ANSI09000976 V3 EN
Figure 121: Simplified logic scheme of the CSPRBRF (50BF) starting logic
30 ms
AND
S
R
OR
Reset A
Retrip Time Out A
BackupTrip A
Section 7
Current protection
BFP Started A
SR
150ms
Q
0
Time out A
AND
ANSI09000976-3-en.vsd
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