Thytronic DMC3S - Page 93

93
DMC3S - Manual - 08 - 2021
Rapd reclosing + slow reclosing
and subsequent memorized
reclosings
Rapid+slow+memorized reclosing program (79 Mode = Rapid+slow, N.DAR = 1..5).
Figure 5 below shows a rapid reclosing followed by a fault which opens the breaker within the neu-
tralisation time, followed by a slow reclosing and a fault detected beyond t
dl
but within the neutrali-
sation time t
r
; when t
r
times out, the memorized reclosing is run.
If t
d
=0; if the fault occurs immediately, the sequence proceeds with a non-definitive trip and wait for
the first memorized reclosing.
If the fault occurs within t
r
, the sequence opens the breaker and the following memorized reclosing is
run when t
r
expires. Every subsequent memorized reclosing starts timers t
r
and t
dm
. If a fault occurs
within t
r
, but after t
dm
, the sequence opens the breaker and the next memorized reclosing occurs
when t
r
expires; if, on the other hand, the fault is detected within t
dm
, a definitive trip occurs and an
unsuccessful reclosing is reported.
CB CLOSED
CB OPEN
CB OPEN
CB OPEN
CB CLOSED CB CLOSED CB CLOSED
trdt
CB State
Rapid reclosing
t
tsdt
Neutralisation timer
Discrimination timer
tdl tdm
Failed reclosing
tr (trf or trt) tr (trf or trt) tr (trf or trt)
Slow reclosing Memorized reclosing
Figure 5 - Rapid reclosing followed by fault and subsequent slow and memorized reclosings