SOTF is activated when the AR function is enabled or when the AR function is
started and the SOTF should remain active for the reclaim time.
When SOTF is detected, the parameter
SOTF
is active.
If the
Manual close mode
setting is set to FALSE and the circuit breaker
has been manually closed during an autoreclosing shot, the AR unit goes
to an immediate lockout.
If the
Manual close mode
setting is set to TRUE and the circuit breaker
has been manually closed during an autoreclosing shot (the INPRO is
active), the shot is considered as completed.
When SOTF starts, reclaim time is restarted, provided that it is running.
The frequent-operation counter is intended for blocking the autoreclosing function
in cases where the fault causes repetitive autoreclosing sequences during a short
period of time. For instance, if a tree causes a short circuit and, as a result, there
are autoreclosing shots within a few minutes interval during a stormy night. These
types of faults can easily damage the circuit breaker if the AR function is not locked
by a frequent-operation counter.
The frequent-operation counter has three settings:
•
Frq Op counter limit
•
Frq Op counter time
•
Frq Op recovery time
The
Frq Op counter limit
setting defines the number of reclose attempts that are
allowed during the time defined with the
Frq Op counter time
setting. If the set
value is reached within a pre-defined period defined with the
Frq Op counter time
setting, the AR function goes to lockout when a new shot begins, provided that
the counter is still above the set limit. The lockout is released after the recovery
time has elapsed. The recovery time can be defined with the
Frq Op recovery time
setting .
If the circuit breaker is manually closed during the recovery time, the reclaim time is
activated after the recovery timer has elapsed.
9.4.5 Counters
The AR function contains six counters. Their values are stored in a semi-retain
memory. The counters are increased at the rising edge of the reclosing command.
The counters count the following situations.
• COUNTER: counts every reclosing command activation
• CNT_SHOT1: counts reclosing commands that are executed from shot 1
• CNT_SHOT2: counts reclosing commands that are executed from shot 2
• CNT_SHOT3: counts reclosing commands that are executed from shot 3
• CNT_SHOT4: counts reclosing commands that are executed from shot 4
• CNT_SHOT5: counts reclosing commands that are executed from shot 5
The counters are disabled through communication with the
DsaCnt
parameter.
When the counters are disabled, the values are not updated.
1MRS757644 H
Control functions
620 series
Technical Manual
1027
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