Setting Notes - Siemens SIPROTEC 4 Manual

Overcurrent time protection
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Setting Notes

2.15.6
General Settings
The internal automatic reclosure function will only be effective and accessible if address 171 79 Auto Recl.
is set Enabled during configuration. If not required, this function is set to Disabled. The function can be
turned ON or OFF under address 7101 FCT 79.
If no automatic reclosures are performed on the feeder for which the 7SJ80 is used (e.g. cables, transformers,
motors, etc.), the automatic reclosure function is disabled by configuration. The automatic reclosure function
is then completely disabled, i.e. the automatic reclosure function is not processed in the 7SJ80. No messages
exist for this purpose and binary inputs for the automatic reclosure function are ignored. All parameters of
block 71 are inaccessible and of no significance.
Blocking Duration for Manual-CLOSE Detection
Parameter 7103 BLOCK MC Dur. defines the reaction of the automatic reclosure function when a manual
closing signal is detected. The parameter can be set to specify how long the auto reclosure function will be
blocked dynamically in case of an external Manual close-command being detected via binary input (356
>Manual Close ). If the setting is 0, the automatic reclosure function will not respond to a Manual close
signal.
Restraint Time and Dynamic Blocking
The blocking time TIME RESTRAINT(address 7105) defines the time that must elapse, after a successful
reclosing attempt, before the automatic reclosing function is reset. If a protective function configured for
initiation of the automatic reclosure function provokes a new trip before this time elapses, the next reclosing
cycle is started in case of multiple reclosures. If no further reclosure is allowed, the last reclosure will be
classed as unsuccessful.
In general, a few seconds are sufficient. In areas with frequent thunderstorms or storms, a shorter blocking
time may be necessary to avoid feeder lockout due to sequential lightning strikes or flashovers.
A longer restraint time should be chosen if there is no possibility to monitor the circuit breaker (see below)
during multiple reclosing (e.g. because of missing auxiliary contacts and information on the circuit breaker
ready status). In this case, the restraint time should be longer than the time required for the circuit breaker
mechanism to be ready.
If a dynamic blocking of the automatic reclosing function was initiated, then reclosing functions remain
blocked until the cause of the blocking has been cleared. The functional description gives further information
on this topic, see side title "Dynamic Blocking". The dynamic blocking is associated with the configurable
blocking time SAFETY 79 ready. Blocking time is usually started by a blocking condition that has picked up.
Circuit Breaker Monitoring
Reclosing after a fault clearance presupposes that the circuit breaker is ready for at least one TRIP-CLOSE-TRIP
cycle at the time when the reclosing function is initiated (i.e. at the beginning of a trip command):
The readiness of the circuit breaker is monitored by the device using a binary input
It is possible to check the status of the circuit breaker before each reclosure or to disable this option
(address 7113, CHECK CB?):
CHECK CB? = No check, deactivates the circuit breaker check,
CHECK CB? = Chk each cycle, to verify the circuit breaker status before each reclosing command.
Checking the status of the circuit breaker is usually recommended. Should the breaker not provide such a
signal, you can disable the circuit breaker check at address 7113 CHECK CB? (No check), as otherwise
auto-reclosure would be impossible.
The status monitoring time CB TIME OUT can be configured at address 7115 if the circuit breaker check
was enabled at address 7113. This time is set slightly higher than the maximum recovery time of the
circuit breaker following reclosure. If the circuit breaker is not ready after the time has expired, reclosing
is omitted and dynamic blocking is initiated. Automatic reclosure thus is blocked.
Time Max. DEAD EXT. serves for monitoring the dead time extension. The extension can be initiated by the
circuit breaker monitoring time CB TIME OUT and by an external synchronism check.
SIPROTEC 4, 7SJ80, Manual
E50417-G1140-C343-A8, Edition 12.2017
Functions
2.15 Automatic Reclosing System 79
>CB Ready (FNo. 2730).
219

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