Therefore,
90 ln(( 2677685.95 2509056) / (2677685.95 1254555.04)) 192min
operate
t
After the trip, a lockout is released to inhibit reconnecting the tripped circuit. The output
lockout signal LOCKOUT is activated when the temperature of the object is greater than the
set lockout release temperature setting
ResLo
.
_
_
ln
final lockout release
lockout release
final n
t
t
æ ö
Q - Q
= - ×
ç ÷
ç ÷
Q -Q
è ø
EQUATION1177 V1 EN-US (Equation 40)
where:
t
lockout_release
is the time to lockout release
Q
lockout_release
is the lockout release level heat content =
ResLo
× θ
operate
Consider that the current heat content θ
n
is 2700000 and the cooling system is still
ON
, then:
_
0.6 2509056 1505433.6
lockout release
_
90 ln((2677685.95 1505433.6) / (2677685.95 2700000)) 244min
lockout release
t
7.6 Breaker failure protection CCRBRF
IP14514-1 v6
7.6.1 Identification
M14878-1 v5
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Breaker failure protection, 3-phase
activation and output
CCRBRF
SYMBOL-U V1 EN-US
50BF
7.6.2 Application
M13916-3 v8
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.
Breaker failure protection CCRBRF will issue a backup trip command to adjacent circuit
breakers in case of failure to trip of the “normal” circuit breaker for the protected object. The
detection of failure to break the current through the breaker is made either by means of
current measurement or as detection of closed status using auxiliary contact.
1MRK 505 370-UEN D Section 7
Current protection
Busbar protection REB670 175
Application manual
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