Siemens siprotec SJ62 User Manual page 236

SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015
Dynamic blocking is initiated if:
• The maximum number of reclosure attempts has been achieved. If a trip command
now occurs within the dynamic blocking time, the automatic reclosure program will
be blocked dynamically, (indicated by „79 Max. No. Cyc").
• The protection function has detected a three-phase fault and the device is pro-
grammed not to reclose after three-phase faults, (indicated by „79 BLK:3ph
p.u.").
• When the maximal waiting time T DEAD DELAY for the delay of the dead time ini-
tiation by binary inputs runs off without that the binary input „>79 DT St.Delay"
during this time frame has become inactive.
• The action time has elapsed without a TRIP command being issued. Each TRIP
command that occurs after the action time has expired and before the picked-up
element drops out, will initiate the dynamic blocking (indicated by „79 Tact
expired").
• A protective function trips which is to block the automatic reclosure function (as con-
figured). This applies irrespective of the status of the automatic reclosure system
(started / not started) if a TRIP command of a blocking element occurs (indicated
by „79 BLK by trip").
• The circuit breaker failure function is initiated.
• The circuit breaker does not trip within the configured time T-Start MONITOR
after a trip command was issued, thus leading to the assumption that the circuit
breaker has failed. (The breaker failure monitoring is primarily intended for commis-
sionnig purposes. Commissionnig safety checks are often conducted with the
circuit breaker disconnected. The breaker failure monitoring prevents unexpected
reclosing after the circuit breaker has been reconnected, indicated by „79 T-
Start Exp").
• The circuit breaker is not ready after the breaker monitoring time has elapsed, pro-
vided that the circuit breaker check has been activated (address 7113 CHECK CB?
= Chk each cycle, indicated by „79 T-CBreadyExp").
• The circuit breaker is not ready after maximum extension of the dead time Max.
DEAD EXT.. The monitoring of the circuit breaker status and the synchrocheck may
cause undesired extension of the dead time. To prevent the automatic reclosure
system from assuming an undefined state, the extension of the dead time is moni-
tored. The extension time is started when the regular dead time has elapsed. When
it has elapsed, the automatic reclosure function is blocked dynamically and the lock-
out time launched. The automatic reclosure system resumes normal state when the
lock-out time has elapsed and new blocking conditions do not apply (indicated by
„79 TdeadMax Exp") .
• Manual closing has been detected (externally) and parameter BLOCK MC Dur. (T
= 0) was set such that the automatic reclosing system responds to manual closing,
• Via a correspondingly masked binary input (FNo. 2703 „>BLOCK 79"). If the block-
ing takes places while the automatic recloser is in normal state, the latter will be
blocked statically („79 is NOT ready"). The blocking is terminated immediately
when the binary input has been cleared and the automatic reclosure function
resumes normal state. If the automatic reclosure function is already running when
the blocking arrives, the dynamic blocking takes effect („79 DynBlock"). In this
case the activation of the binary input starts the dynamic blocking time SAFETY 79
ready. Upon its expiration the device checks if the binary input is still activated. If
this is the case, the automatic reclosure program changes from dynamic blocking
to static blocking. If the binary input is no longer active when the time has elapsed
and if no new blocking conditions apply, the automatic reclosure system resumes
normal state.
2.14 Automatic Reclosing System 79
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