•
Lockout
This state can be reached following a complete autoreclose sequence where the fault has persisted to the
final shot. Typically this is because the protection has operated during the final reclaim time or the
circuit‑breaker is open at the end of the final reclaim time. In these cases the output 79 Last Trip
Lockout is raised as well as 79 Lockout. Lockout can also be reached by operation of the 79
Lockout input at any time or invalid circuit‑breaker status from the binary inputs. Lockout is also
reached from within an autoreclose sequence if a failure occurs such as CB fail to close, expiry of the 79
Sequence Fail Timer, 79 Reclose Blecked Delay or check synchronizing conditions are not
met at Close Inhibit or the 79 HS Trips to Lockout or 79 Delayed Trips to Lockout is
reached. The Lockout state can be configured with a minimum time for which the state is held to allow
other systems to react and can be set to automatically reset at the end of this time or to be retained until
manually reset. A CB Manual Close operation will reset the 79 Lockout alarm and the autoreclose
will return to the In Service state unless the 79 Lockout input is permanently raised or CB status is
invalid. The Lockout condition can not be reset if there is an active lockout input.
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.
If the Lockout command is received while a Manual Close operation is in progress, the feature is
immediately locked-out.
Once the Lockout condition has been reached, it will be maintained until reset. The following will reset
lockout:
– By a Manual Close command, from fascia, comms or close CB binary input
– By a 79 Reset Lockout binary input, provided there is no signal present that will cause lockout
– At the end of the 79 Minimum LO Delay time setting if 79 Reset LO by Timer is selected to
Enabled, provided there is no signal present which will cause lockout
– Where lockout was entered by an A/R Out signal during an autoreclose sequence then a 79 In
signal must be received before lockout can reset
– By the CB closed binary input, provided there is no signal present which will cause lockout
The lockout condition has a delayed drop-off of 2 s. The lockout condition can not be reset if there is an
active lockout input.
Interaction of Automatic Reclosing Function and Protection Functions
Autoreclose is started by operation of a protection element which is mapped as a 79 Trigger. These are
selected by settings that are found in the menus for each fault type within the 79 settings:
•
79 PF Triggers allows 50 and 51 overcurrent elements to be selected as autoreclose triggers
•
79 EF Triggers allows 50N, 50G, 51N and 51G earth fault elements to be selected as autoreclose triggers
Control Functions
7.3 79 Automatic Reclosing
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual 431
C53000-G7040-C014-1, Edition 11.2019
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