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1MRK 505 370-UEN D
Therefore,
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
t
lockout release
_
EQUATION1177 V1 EN-US
where:
t
lockout_release
Q
lockout_release
Consider that the current heat content θ
lockout release
_
t
lockout release
_
7.6
Breaker failure protection CCRBRF
7.6.1
Identification
Function description
Breaker failure protection, 3-phase
activation and output
7.6.2
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.
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.
Busbar protection REB670
Application manual
t
90 ln((2677685.95 2509056) / (2677685.95 1254555.04)) 192 min
operate
æ
Q
- Q
t
= - × ç
final
lockout release
ln
ç
Q
è
final
is the time to lockout release
is the lockout release level heat content =
0.6 2509056 1505433.6
90 ln((2677685.95 1505433.6) / (2677685.95 2700000)) 244 min
ResLo .
ö
_
÷
÷
- Q
ø
n
is 2700000 and the cooling system is still
n
IEC 61850
IEC 60617
identification
identification
CCRBRF
3I>BF
SYMBOL-U V1 EN-US
Current protection
ResLo × θ
operate
ANSI/IEEE C37.2
device number
50BF
Section 7
(Equation 40)
ON , then:
IP14514-1 v6
M14878-1 v5
M13916-3 v8
175
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