ABB RELION 620 Series Technical Manual page 735

1MAC504801-IB E
620 series ANSI
Technical Manual
cases, SOTF is activated, but only for the reclaim time after energizing the power line and
only when the circuit breaker is closed manually and not by the AR function.
SOTF disables any initiation of an autoreclosing shot. The energizing of the power line is
detected from the CB_POS information.
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
Section 9
Control functions
729