Table 260: CCRBRF (50BF) Non group settings (basic)
Name Values (Range) Unit Step Default Description
GlobalBaseSel 1 - 12 - 1 1 Selection of one of the Global Base Value
groups
8.8.6 Monitored data
PID-3562-MONITOREDDATA v5
Table 261: CCRBRF (50BF) Monitored data
Name Type Values (Range) Unit Description
IA REAL - A Measured current in phase A
IB REAL - A Measured current in phase B
IC REAL - A Measured current in phase C
IN REAL - A Measured residual current
8.8.7 Operation principle
M16914-3 v11
Breaker failure protection CCRBRF (50BF) is initiated from the protection trip command, either
from protection functions within the IED or from external protection devices.
To this function the three-phase current input and/or change to: the breaker normally open
auxiliary contact (i.e. "52a" or "closed") shall be connected. On OHL feeders where single pole auto-
reclosing is used, auxiliary contact from each CB pole shall be connected separately
The input START signal (i.e. initiate signal) can be phase selective or common (for all three phases).
Phase selective start signals enable single pole retrip functionality. This means that a second
attempt to open the same breaker can be done phase-selective. The retrip attempt is made after a
set time delay
t1
. For transmission lines, single pole trip and auto-reclosing is often used. The
retrip function can be phase selective if it is initiated from the phase selective line protection.
The re-trip function can be done with or without
FunctionMode
check. With this check, the re-trip
is only performed if the circuit breaker is still seen as closed when
t1
timer has elapsed.
The INITIATE signal will also start the backup trip timer. The function detects the successful
breaker opening, either by detection of low current through RMS evaluation and a special adapted
current algorithm or by monitoring the circuit breaker status using normally open auxiliary contact
from the breaker. The special algorithm enables a very fast detection of successful breaker
opening, which is, fast resetting of the current measurement. If the function has not detected
breaker opening before the backup timer has run-out its time a backup trip is initiated.
Further the following possibilities are available:
• Three phase (i.e. common) start/initiation via input INITIATE or individual start/initiation per
phase by using phase segregated inputs STLx.
• The minimum length of the retrip pulse, the backup trip pulse and the second backup trip
pulse are settable. This pulse duration is defined by a parameter setting
tPulse
. The retrip
pulse, the backup trip pulse and the second backup trip pulse will however sustain as long as
there is an indication of closed breaker.
• If the current detection is used 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
1MRK 502 066-UUS B Section 8
Current protection
527
Technical manual
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