73
NA11 - Manual - 02 - 2009
FUNCTION CHARACTERISTICS
Unsuccessful rapid + slow reclosure; 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
d1
;
The automatic reclosing system is blocked and a failed reclosure command is issued.
Rapid + slow reclosures and
subsequent delayed reclosures
Successful rapid + slow + delayed reclosures; 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.
The delayed reclosure starts the timer
t
d2
(Delayed reclosure fault discrimination time); at the same
time the reclaim timer
t
r
is started; if no more trip within
t
r
, once the reclaim time has elapsed, the
system comes back to reset.
Vice versa, if a further trip within
t
d2
arises, the automatic reclosing system is blocked and a failed
reclosure command is issued.
Following trips after the
t
d2
(Delayed reclosure fault discrimination time) up to fi ve reclosures may be
programmed by means the N.DAR parameter available inside the
Set \ Auto-reclose - 79
menu.
The intentional CB closing command start the reclaim (
t
r
) and Manual close fault discrimination (
t
d
)
timers.
With Rapid-reclose setting (79 Mode = Rapid), any trip within the
t
r
time interval causes a blocking
of the sequence and a failed reclosure signal is issued (Unsuccessful rapid reclosure).
With Rapid+Slow reclose setting (79 Mode = Rapid+Slow) and
t
d
timer enabled (MC-td-EN=ON), any
trip inside the
t
d
time interval causes a a block of the reclosure sequence and a failed reclosure
signal is issued, whereas any trip inside the
t
r
time interval and after the
t
d
time interval issues an
open CB command and a delayed reclosure attempt.
CB CLOSED
CB CLOSED
CB OPEN
CB OPEN
CB OPEN
CB CLOSED
79RLF-diafram.ai
t
rdt
CB State
t
t
sdt
Richiusura rapida seguita da guasto e successiva richiusura lenta operata su guasto
Timer di neutralizzazione
Timer di discriminazione
t
r
t
r
t
d1
Fallita richiusura
CB CLOSED
CB CLOSED
CB OPEN
CB OPEN
CB OPEN
CB CLOSED
79RLF-diafram.ai
t
rdt
CB State
t
t
sdt
Richiusura rapida seguita da guasto e successiva richiusura lenta operata su guasto
Timer di neutralizzazione
Timer di discriminazione
t
r
t
r
t
d1
Fallita richiusura
CB CLOSED
CB OPEN
CB OPEN
CB OPEN
CB CLOSED
CB CLOSED
CB CLOSED
t
rdt
CB State
t
t
sdt
Ri hi
id
i
d
i
i hi
l
i
Timer di neutralizzazione
Timer di discriminazione
t
r
t
r
t
r
t
d1
t
d2
Fallita richiusura
CB CLOSED
CB OPEN
CB OPEN
CB OPEN
CB CLOSED
CB CLOSED
CB CLOSED
t
rdt
CB State
t
t
sdt
Ri hi
id
i
d
i
i hi
l
i
Timer di neutralizzazione
Timer di discriminazione
t
r
t
r
t
r
t
d1
t
d2
Fallita richiusura