2.13 Automatic reclosure function (optional)
231
7SA522 Manual
C53000-G1176-C155-3
Example 3: 3 cycles are set. At least the first two cycles are set such that they can start
the recloser. The action times are set as in example 1. The first protection trip takes
place 0.5s after starting. Since the action time for the 1st cycle has already expired at
this time, it cannot start the automatic reclosure function but the 2nd cycle, for which
starting is allowed, is activated immediately. This 2nd cycle therefore starts the auto-
matic reclosure circuit, the 1st cycle is practically skipped.
Control Mode of the
Automatic Reclo-
sure
The dead times — these are the times from elimination of the fault (dropout of the trip
command or signalling via auxiliary contacts) to the initiation of the automatic close
command — may vary, depending on the automatic reclosure control mode selected
when determining the functional scope and the resulting signals of the starting protec-
tive functions.
In control mode 75,3 (With TRIP command) single-pole
or single/three-pole
reclose cycles are possible if the device and the circuit-breaker are suitable. In this
case different dead times after single-pole tripping on the one hand and after three-
pole tripping on the other hand are possible (for every reclose cycle). The protective
function that issues the trip command determines the type of trip: single-pole or three-
pole. Depending on the latter the dead time is selected.
In control mode 3,&.83(With PICKUP...) different dead times can be set for
every reclosure cycle after single-phase
, two-phase and three-phase faults. Selection
of the dead time in this case depends on the type of fault determined by the initiating
protection function at the instant that the trip commands reset. This operating mode
allows the dead times to be dependent on the type of fault in the case of three-pole
reclose cycles.
Reclose Block Different conditions lead to blocking of the automatic reclosure. No reclosure is for
example possible if it is blocked via a binary input. If the automatic reclosure has not
yet been started, it cannot be started at all. If a reclose cycle is already in progress,
dynamic blocking takes place (see below).
Each individual cycle may also be blocked via binary input. In this case the cycle con-
cerned is declared as invalid and will be skipped in the sequence of permissible
cycles. If blocking takes place while the cycle concerned is already running, this leads
to aborting of the reclosure, i.e. no reclosure takes place even if other valid cycles
have been parameterized.
Internal blocking signals, with a limited duration, arise during the course of the reclose
cycles:
The reclaim time 75(&/$,0 begins with every automatic reclosure command. If the
reclosure is successful, all the functions of the automatic reclosure return to the qui-
escent state at the end of the reclaim time; a fault after expiry of the reclaim time is
treated as a new fault in the network. Re-tripping by a protection function during the
reclaim time initiates the next reclose cycle in the case of multiple reclosure; if no
further reclosure is permitted, the last reclosure cycle is declared as unsuccessful if
re-tripping within the reclaim time takes place. The automatic reclosure is blocked dy-
namically.
The dynamic lock-out locks the reclosure for the duration of the dynamic lock-out time
(0.5s). This occurs for example after a final
tripping or other events which block the
automatic reclosure after it has been started. Restarting is locked out for this time.
When this time expires, the automatic reclosure function returns to its quiescent state
and is ready for a new fault in the power system.
If the circuit breaker is closed manually (by the control discrepancy switch connected
to a binary input, the local control functions or via one of the serial interfaces), the au-
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