ABB Relion REG670, Applications Manual

Page: 376 / 780

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.
ResLo : 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.
ResLo 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.
9.8 Breaker failure protection CCRBRF
9.8.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Breaker failure protection, 3-phase
activation and output
CCRBRF
3I>BF
SYMBOL-U V1 EN
50BF
9.8.2 Application
In the design of the fault clearance system the N-1 criterion is often used. This means
that a fault needs to be cleared even if any component in the fault clearance system is
faulty. One necessary component in the fault clearance system is the circuit breaker.
It is from practical and economical reason not feasible to duplicate the circuit breaker
for the protected object. Instead a breaker failure protection is used.
Section 9
1MRK 502 071-UEN -
Current protection
370 Generator protection REG670 2.2 IEC and Injection equipment REX060, REX061, REX062
Application manual