ABB REL650 Applications Manual page 241

1MRK 506 334-UUS A
Application manual
Table 13: Dependencies between parameters RetripMode and FunctionMode
RetripMode
Retrip Off
CB Pos Chec k
No CB Pos Check
BuTripMode: Back-up trip mode is given to state sufficient current criteria to detect
failure to break. For Current operation 2 out of 4 means that at least two currents, of the
three phase-currents and the residual current, shall be high to indicate breaker failure. 1 out
of 3 means that at least one current of the three phase-currents shall be high to indicate
breaker failure. 1 out of 4 means that at least one current of the three phase currents or the
residual current shall be high to indicate breaker failure. In most applications 1 out of 3 is
sufficient. For Contact operation means back-up trip is done when circuit breaker is closed
(breaker position is used).
Pickup_PH: Current level for detection of breaker failure, set in % of IBase. This
parameter should be set so that faults with small fault current can be detected. The setting
can be chosen in accordance with the most sensitive protection function to start the breaker
failure protection. Typical setting is 10% of IBase.
Pickup_BlkCont: If any contact based detection of breaker failure is used this function can
be blocked if any phase current is larger than this setting level. If the FunctionMode is set
Current and Contact breaker failure for high current faults are safely detected by the
current measurement function. To increase security the contact based function should be
disabled for high currents. The setting can be given within the range 5 – 200% of IBase.
Pickup_N: Residual current level for detection of breaker failure set in % of IBase. In high
impedance grounded systems the residual current at phase to ground faults are normally
much smaller than the short circuit currents. In order to detect breaker failure at single-
phase ground faults in these systems it is necessary to measure the residual current
separately. Also in effectively grounded systems the setting of the ground-fault current
protection can be chosen to relatively low current level. The BuTripMode is set 1 out of 4.
FunctionMode
N/A
Current
Contact
Current&Contact
Current
Contact
Current&Contact
Section 7
Current protection
Description
The re-trip function is not
activated
A phase current must be larger
than the operate level to allow re-
trip
Re-trip is done when circuit
breaker is closed (breaker
position is used) and a long
duration of a trip signal indicates
breaker failure
Both methods are used
Re-trip is done without check of
breaker position
Re-trip is done without check of
breaker position
Both methods are used
235