Siemens SIPROTEC 4 7VK61 Manual page 47

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 0.5 s 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 initiating is allowed, is activated immediately. This 2nd cycle therefore starts the automatic
reclosure function, the 1st cycle is practically skipped.
Operating modes of the automatic reclosure function
The dead times — these are the times from elimination of the fault (drop off of the trip command or signaling
via auxiliary contacts) to the initiation of the automatic close command — may vary depending on the auto-
matic reclosure function operating mode selected when determining the function scope and the resulting
signals of the starting protection functions.
In control mode TRIP... (With TRIP command ...), 1-pole or 1-/3-pole reclose cycles are possible if the device
and the circuit breaker are suitable. In this case, different dead times (for every AR cycle) are possible after 1-
pole tripping and after 3-pole tripping. The protection function that issues the trip command determines the
type of trip: 1-pole or 3-pole. The dead time is controlled dependent on this.
In control mode PICKUP ... ... (With PICKUP...), different dead times can be set for every reclose cycle
after 1-, 2- and 3-phase faults. The pickup diagram of the protection functions at the instant when the trip
command disappears is the decisive factor. This mode allows the dead time to be made dependent on the type
of fault in the case of 3-pole tripping applications.
Blocking reclosure
Different conditions lead to blocking of the automatic reclosure function. No reclosure is possible, for
example, if it is blocked via a binary input. If the automatic reclosure function has not yet been started, it
cannot be started at all. If a reclosure 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 concerned 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 T-RECLAIM (address 3403) is started with each automatic reclosure command, the only
exception is the ADT mode where the reclaim time can be disabled by setting it to 0 s. If the reclosure is
successful, all functions of the automatic reclosure function return to the idle state at the end of the reclaim
time; a fault after expiry of the reclaim time is treated as a new fault in the power system. If the reclaim time is
disabled in ADT mode, each new trip after reclosing is considered as a new fault. If one of the protection func-
tions causes another trip during the reclaim time, the next reclosure cycle will be started if multiple reclosure
has been set. If no further reclosure attempts are permitted, the last reclosure is regarded as unsuccessful in
case of another trip during the reclaim time. The automatic reclosure function is blocked dynamically.
The dynamic lock-out locks the reclosure for the duration of the dynamic lock-out time (0.5 s). This occurs, for
example, after a final trip or other events which block the auto reclose function after it has been started.
Restarting is blocked during this time. When this time expires, the automatic reclosure function returns to its
quiescent state and is ready for a new fault in the network.
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 automatic reclosure function is blocked for a
manual-close-blocking time T-BLOCK MC, address 3404. If a trip command occurs during this time, it can be
assumed that a metallic short-circuit is present (e.g. closed earth switch). Every trip command within this time
is therefore final. With the user definable logic functions (CFC) further control functions can be processed in
the same way as a manual–close command.
Interrogation of the Circuit Breaker Ready State
A precondition for automatic reclosure function following clearance of a short-circuit is that the circuit breaker
is ready for at least one OPEN-CLOSE-OPEN-cycle when the automatic reclosure circuit is started (i.e. at the
time of the first trip command). The readiness of the circuit breaker is signaled to the device via the binary
input >CB1 Ready (No. 371). If no such signal is available, the circuit breaker interrogation can be
suppressed (presetting of address 3402) as automatic reclosure function would otherwise not be possible at
all.
SIPROTEC 4, 7VK61, Manual
C53000-G1176-C159-5, Edition 05.2018
2.2 Automatic reclosure function (optional)
Functions
47