ABB Relion 670 Series Applications Manual page 191

1MRK 511 401-UUS F
Protection
operate time
The fault
occurs
ANSI05000479 V3 EN-US
Figure 88: Time sequence
t2MPh : Time delay of the backup trip at multi-phase initiate. The critical fault clearance time is
often shorter in case of multi-phase faults, compared to single phase-to-ground faults. Therefore
there is a possibility to reduce the backup trip delay for multi-phase faults. Typical setting is 90 –
150 ms.
Note that for a protected object which are always tripped three-phase (e.g. transformers,
generators, reactors, cables, etc.) this timer shall always be set to the same value as
t3 : Additional time delay to t2 for a second backup trip TRBU2. In some applications there might
be a requirement to have separated backup trip functions, tripping different backup circuit
breakers.
tCBAlarm : Time delay for alarm in case of indication of faulty circuit breaker. There is a binary
input 52FAIL from the circuit breaker. This signal is activated when internal supervision in the
circuit breaker detect that the circuit breaker is unable to clear fault. This could be the case when
gas pressure is low in a SF6 circuit breaker, of others. After the set time an alarm is given, so that
actions can be done to repair the circuit breaker. Note that the time delay for backup trip
bypassed when the 52FAIL is active. Typical setting is 2.0 seconds..
tPulse : Trip pulse duration. This setting must be larger than the opening time of circuit breakers to
be tripped from the breaker failure protection. Typical setting is 200 ms.
tStartTimeout : When one of the two "Follow Modes" is used, there is a settable timer
tStartTimeout which will block the external START input signal when it times-out. This will
automatically also reset the
At the same time the STALARM output from the function will have logical value one. To reset that
condition external
operation of the breaker failure function for cases where a permanent
mistake (e.g.due to a fault in the station battery system). Note that any backup trip command will
inhibit running of
Bay control REC670
Application manual
Normal t
cbopen
Retrip delay t1 t
cbopen
Minimum back-up trip delay t2
Critical fault clearance time for stability
Trip and Pickup
CCRBRF
(50BF)
t1 and t2 timers and consequently prevent any backup trip command.
START signal shall be removed. This is done in order to prevent unwanted
tStartTimeout timer.
© Copyright 2017 ABB. All rights reserved
after re-trip
t
BFPreset
Margin
Current protection
Time
ANSI05000479_3_en.vsd
t2 timer.
START signal is given by
Section 8
t2 is
185