Functionality
USER MANUAL FPC 200 - 3/2017 69
Auto-reclosing function - ANSI 79 - AR
Approximately 85 % of all faults occurring at overhead lines have temporary short circuit character. After protection
operation they usually disappear. Line is switched back into operation the moment when fault is not present anymore
and any delay runs out. Reclosing is executed with auto-reclosing function. If the fault is still present after reclosing the
protection function will operate again. Based on setting the process of reclosing can repeat several times.
2.6.3.1 Functionality
The auto-reclosing function (AR) can be used with any
circuit breaker suitable for auto reclosing. Four
programmable AR shots are provided. Combined with
dead time duration user can form a scenario which will
be executed in case of fault occurrence.
Auto reclose function is set in standby mode when it is
enabled and no blocking or trip signals are present. The
function monitors trip signals. When any of them is
triggered the function operates according to defined
scenario.
In case when the last auto-reclosing shot is still
unsuccessful a final trip order is given and AR function is
blocked until circuit breaker close command is initiated.
Reclosing is considered successful when no trip signal
appears after reclosing during the Reclaim time (Figure
2.44). In case of dynamic blocking, scenario is reset after
one second delay. In case of fault appearing before
reclaim time has passed AR function will continue with
next cycle if any left.
Trip
Close command
1.st dead time
ARC not ready
2.nd dead time
Max. pulse
Reclaim
time
Reclaim time
ARC in progress
Max. pulse
CB open
Manual closing
Figure 2.44: Automatic reclosing successful in second attempt.
Trip
Close command
1.st dead time
ARC not ready
Reclaim
time
ARC in progress
Max. pulse
Definite trip blocked
CB open
Manual closing
Block delay
Figure 2.45: Unsuccessful automatic reclosing, dynamic block.
To Next Page
Loading...
Need help?
General
