2 Functions
132
7SD610 Manual
C53000-G1176-C145-4
As is shown by the example, the adaptive dead time has the following advantages:
• The circuit breaker at position II is not reclosed at all if the fault persists and is not
unnecessarily stressed as a result.
• With non-selective tripping on an external fault by an overreaching time-graded pro-
tection, no further auto-reclosure attempts can be generated there because the fault
current path via busbar B and position II remains interrupted even after several re-
closure attempts.
• At position I overreach is allowed in the case of multiple reclosures and even in the
event of final tripping because the line remains open at position II and therefore no
actual overreach can occur at I.
CLOSE Command
Transmission
(Remote-CLOSE)
With close command transmission via the digital connection path the dead times are
only set at one line end. The other end is set to "Adaptive Dead Time (ADT)". The latter
only react to the received close commands from the transmitting end. An adaptive
dead time is thus possible even without a voltage.
The transmission of the close command by the transmitting line end is delayed until it
is sure that the local reclosure was successful. This means that after reclosure a pos-
sible local pickup is still waited for. This delay prevents unnecessary closing at the
remote end on the one hand but also increases the time until reclosure takes place
there. This is not critical for a single-pole reclosure or in radial or meshed networks if
no stability problems are expected under these conditions.
Figure 2-46 AR Remote-Close function via protection data interface
The close command can be transmitted by a teleprotection scheme using the protec-
tion data interfaces. When the indication „AR Remote Close“ is output, this infor-
mation is transmitted at the same time to the remote end via the protection data inter-
face. The information is OR-combined with the information of the binary input „>AR
RemoteClose“ and made available to the automatic reclosure. (Figure 2-46).
Connecting an Ex-
ternal Auto-Reclo-
sure Device
If the 7SD610 has to work with an external reclosure device, the binary inputs and
outputs provided for this purpose must be taken into consideration. The following
inputs and outputs are recommended:
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