Breaker Failure Protection Ccrbrf(50Bf); Identification - ABB REB670 Applications Manual

1MRK 505 337-UUS -
7.6
7.6.1
Application manual
• In case a total interruption (low current) of the protected transformer all cooling
possibilities will be inactive. This can result in a changed value of the time constant.
• If other components (motors) are included in the thermal protection, there is a risk of
overheating of that equipment in case of very high current. The thermal time constant
is often smaller for a motor than for the transformer.
ITrip: The steady state current that the transformer can withstand. The setting is given in
% of IBase1 or IBase2.
Alarm1: Heat content level for activation of the signal ALARM1. ALARM1 is set in % of
the trip heat content level.
Alarm2: Heat content level for activation of the output signal ALARM2. ALARM2 is set
in % of the trip heat content level.
LockoutReset: Lockout release level of heat content to release the lockout signal. When
the thermal overload protection trips a lock-out signal is activated. This signal is intended
to block switching on of the protected circuit transformer as long as the transformer
temperature is high. The signal is released when the estimated heat content is below the set
value. This temperature value should be chosen below the alarm temperature.
LockoutReset is set in % of the trip heat content level.
ThetaInit: Heat content before activation of the function. This setting can be set a little
below the alarm level. If the transformer is loaded before the activation of the protection
function, its temperature can be higher than the ambient temperature. The start point given
in the setting will prevent risk of no trip at overtemperature during the first moments after
activation. ThetaInit: is set in % of the trip heat content level.
Warning: If the calculated time to trip factor is below the setting Warning a warning signal
is activated. The setting is given in minutes.

Breaker failure protection CCRBRF(50BF)

Identification

Function description
Breaker failure protection, 3-phase
activation and output
IEC 61850 IEC 60617
identification identification
CCRBRF
3I>BF
SYMBOL-U V1 EN
Section 7
Current protection
ANSI/IEEE C37.2
device number
50BF
201