Thytronic DMC3S, Manual

Page: 92 / 110

92
DMC3S - Manual - 08 - 2021
Rapid reclosing program (79 Mode = Rapid).
Figure 2 below shows a rapid reclosing followed by a fault resulting in breaker opening during the
neutralisation time ( t
rf
or t
rt
).
Any trip during the neutralisation time ( t
rf
or t
rt
) opens the breaker, blocking of the reclosings and a
reclosing failure report.
The automation returns to standby once the neutralisation timer has counted down (the greater of t
rf
and t
rt
) which follows a condition of the breaker closed manually without faults.
Rapid reclosing and slow re-
closing
Rapid+slow reclosing program (79 Mode = Rapid+slow).
Figure 3 below shows a rapid reclosing followed by a fault resulting in breaker opening during the
neutralisation time ( t
rf
or t
rt
). A slow reclosing is actuated after a programmable time t
sdt
; if no faults
occur during the neutralisation time, the slow reclosing is successful and the automation returns to
standby.
Figure 4 below shows a rapid reclosing followed by a fault which opens the breaker within the neu-
tralisation time ( t
rf
or t
rt
) followed by a slow reclosing run on the fault within the discrimination time
t
dl
; the reclosing is considered unsuccessful and the respective report is issued. (if no memorized
reclosings have been programmed the reclosing is considered unsuccessful even if the fault occurs
within the neutralisation time)
CB CLOSED CB OPEN CB OPEN CB CLOSED
trdt
CB State
t
MANUAL CLOSING
Neutralisation timer
Failed reclosing
tr (trf or trt) tr (max of trf, trt)
Rapid reclosing
79 in standby
CB CLOSED
Figure 2 - Failed rapid reclosing
CB CLOSED
CB CLOSED CB OPEN CB OPEN CB CLOSED
trdt
CB State
t
tsdt
Neutralisation timer
tdl tdr
Discrimination timer
tr (trf or trt) tr (trf or trt)
Rapid reclosing Slow reclosing 79 in standby
Figure 3 - Rapid reclosing followed by fault and subsequent successful slow reclosing
CB CLOSED
CB CLOSED CB OPEN CB OPEN CB OPEN CB CLOSED
trdt
CB State
t
tsdt
Neutralisation timer
Discrimination timer
Failed reclosing
tr (trf or trt) tr (trf or trt)
tdl
Rapid reclosing Slow reclosing
Figure 4 - Rapid reclosing followed by fault and subsequent slow reclosing on fault