Siemens 7SR10 Argus Series, Manual

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7SR10 Description of Operation
©2018 Siemens Protection Devices Limited Chapter 1 Page 54 of 77
4.1.3
Autoreclose Prot’n Menu
This menu presents the Overcurrent Protection elements available for each type of Fault i.e. P/F, E/F (N/G) or
SEF and allows the user to select those that are to be applied as Inst trips ; those that are to be applied as
Delayed Trips
; and those that are to be applied as
HS Trips
(HighSet), as required by the selected sequence.
There is no corresponding setting for External as the External protection type is not normally controlled by the
Auto Reclose Relay. The resultant configuration enables the Auto Reclose function to correctly apply the required
Protection for each shot in a sequence.
4.1.4
Autoreclose Config Menu
This menu allows the following settings to be made:-
79 Autoreclose Enabled turns ON all AutoReclose Functions.
79 Num Shots Sets the allowed number of AutoReclose attempts in a sequence.
79 Retry Enable Enabled
configures the relay to perform further attempts to automatically Close the
Circuit Breaker where the CB has initially failed to close in response to a Close
command. If the first attempt fails the relay will wait for the
79 Retry Interval
to expire
then attempt to Close the CB again.
79 Retry Attempts
Sets the maximum number of retry attempts.
79 Retry Interval Sets the time delay between retry attempts.
79 Reclose Blocked
Delay If the CB is not ready to receive a Close command or if system conditions are such
that the CB should not be closed immediately e.g. a close-spring is not charged, then
a Binary input mapped to Reclose Block can be raised and the Close pulse will not be
issued but will be held-back. The 79 Reclose Blocked Delay sets the time Reclose
Block is allowed to be raised, if this time delay expires the Relay will go to Lockout. If
Reclose Block is cleared, before this time expires, then the CB Close pulse will be
issued at that point in time. Dead Time + Reclose Blocked Delay = Lockout.
79 Sequence Fail Timer Sets the time that AutoReclose start can be primed. Where this time expires before all
the DAR start signals are not received i.e. the CB has opened, protection pickups have
reset and the trip relay has reset, the Relay goes to Lockout.
79 Sequence Co-Ord When set to Enabled the Relay will co-ordinate its sequence and shot count such that
it automatically keeps in step with downstream devices as they advance through their
sequence. The Relay detects that a pickup has operated but has dropped-off before its
associated time delay has expired, it then increments its Shot count and advances to
the next stage of the auto-reclose sequence without issuing a trip, this is repeated as
long as the fault is being cleared by the downstream device such that the Relay moves
through the sequence bypassing the INST Trips and moving on to the Delayed Trip to
maintain Grading margins.
Notes on the ‘Lockout’ State
The Lockout state can be reached for a number of reasons. Lockout will occur for the following: -
• At the end of the 79 Sequence Fail Timer .
• At the end of the Reclaim timer if the CB is in the open position.
• A protection operates during the final Reclaim time.
• If a Close Pulse is given and the CB fails to close.
• The 79 Lockout binary input is active.
• At the end of the
79 Reclose Blocked Delay
due to presence of a persistent Block signal.
• When the 79 Elem HS Trips to Lockout count is reached.
• When the 79 Elem Delayed Trips to Lockout count is reached.
An alarm output is provided to indicate last trip to lockout .
Once lockout has occurred, an alarm (
79 Lockout
) is issued and all further Close commands, except manual
close, are inhibited.