Thytronic NA011 - Page 43

FUNCTION CHARACTERISTICS
43
NA011 - Manual - 05 - 2022
Rapid +Slow reclosing
With Rapid+Slow reclose setting (79 Mode = Rapid+Slow) if a fault (CB opening command) oc-
curs within the reclaim time, after the slow reclosure dead time (t
sdt
) a slow reclosure is operated.
Because no trip occurs within the reclaim time the system comes back to reset; any new trip starts
a rapid + slow reclosing sequence again (Successful rapid + slow reclosure).
Conversely if a new fault (CB opening command) occurs within the reclaim time and the next slow
reclosure is issued with fault within the slow reclosure fault discrimination time t
d
the automatic
reclosing system is blocked and a failed reclosure command is issued (unsuccessful rapid + slow
reclosure).
Rapid + slow reclosures and
subsequent delayed reclosures
With Rapid+Slow reclose setting (79 Mode = Rapid+Slow) and more than zero reclosures are
enabled (79N.DAR = 1...5) if a fault (CB opening command) occurs within the reclaim time, after
the slow reclosure dead time (t
sdt
) a slow reclosure is operated on fault detected later than t
d1
but
within the reclaim time t
r
; once the reclaim time has elapsed, the delayed reclosing is issued.
CB CLOSED
CB OPEN
CB OPEN
CB OPEN
CB CLOSED CB CLOSED CB CLOSED
79RLM-diafram.ai
t
rdt
CB State
t
t
sdt
Reclaim timer
Discrimination timer
t
r
t
r
t
r
t
d
t
d
Failed reclosure
Rapid reclosure over a fault and subsequent slow and delayed reclosures
CB CLOSED
CB CLOSED
CB OPEN
CB OPEN
CB CLOSED
79RL-diafram.ai
t
rdt
CB State
t
t
sdt
Rapid reclosure over a fault and subsequent successfully slow reclosure
t
r
t
r
t
d
Reclaim timer
Discrimination timer
CB CLOSED
CB CLOSED
CB OPEN
CB OPEN CB OPEN
CB CLOSED
79RLF-diafram.ai
t
rdt
CB State
t
t
sdt
t
r
t
r
t
d
Rapid reclosure over a fault and subsequent slow reclosure still over a fault
Reclaim timer
Discrimination timer
Failed reclosure