The autoreclose function can provide a number of reclosing attempts (shots). The function has a number of
configuration settings which are used for all fault types.
The autoreclose sequence is defined by settings for the number of shots and deadtimes for different fault
types: phase fault (50, 51), earth fault (50G, 50N, 51G, 51N) or sensitive earth fault (50GS, 51GS) and
external fault (via binary input configured as 79 Ext Trip).
An autoreclose shot is initiated from operation of a protection trip that has been configured as an autoreclose
trigger for one of the fault types for a circuit‑breaker that is in service. If a circuit‑breaker is already in the open
position before the trip occurs, autoreclose will not be started. Any of the protection elements can be config-
ured as a trigger for its respective type or can be configured to trigger as an external trip by configuration of
suitable user logic. A protection operation which is not configured as an autoreclose trigger can still be config-
ured to trip the circuit‑breaker but will not initiate autoreclose. A protection operation can be mapped to
lockout the autoreclose if required. This will ensure that autoreclose is not started following that element
operation to prevent simultaneous operation of other elements from starting autoreclose.
The autoreclose operates as a sequence of states where the state is changed when actions occur and a typical
sequence is as follows:
•
In service (wait for trip)
•
Trip CB from a protection that is configured as a 79 Trigger
•
Sequence in progress (wait for trip reset and CB Open)
•
Deadtime (timeout dependent on initiating trip type)
•
Close inhibit (check voltage levels, synchronizing requirements and for any block signals)
•
Close pulse (send close command and check for trip)
•
Reclaim (wait for trip, increment shot number and return to Sequence In Progress or timeout, raise
Successful Autoreclose and return to In Service.
A sequence can be stopped due to some actions or errors which result in:
•
• Lockout (alarm and wait for manual reset or reset automatically by timer)
After the first reclose (shot) the reclaim time starts. If another trip occurs within the reclaim time, the shot
number is incremented and the deadtime is selected depending on the trip type for that shot. This is handled
as the next shot in the same sequence. A common shot counter is used which is applied regardless of the
element type which causes the trip. The maximum number of shots is configured by setting and the sequence
can be shortened for particular fault types by additionally configuring the maximum number of HS Trips,
Delayed Trips and Extern Trips to Lockout. If a trip does not occur during the reclaim time,
Successful Autoreclose is reported and the autoreclose resets to shot 1 and waits for a trip to start a
new sequence.
The 79 Lockout input can be used to cancel an autoreclose sequence or prevent starting. The 79 Block
Reclose input is used to temporarily inhibit the close operation until conditions are correct. This is typically
used with different circuit‑breaker designs for signals such as “spring charging” or “low air pressure” which can
be cleared during the sequence allowing the sequence to continue whereas the Lockout input is used for
unrecoverable conditions such as low gas (SF6) pressure.
The Hot Line function is provided to improve safety when personel are working near to live primary equip-
ment. The feature is manually switched in during these conditions and will initiate instantaneous CB tripping
and Lockout for the pickup of any overcurrent (50, 51), earth fault (50G, 50N, 51G, 51N) or sensitive earth
fault (50GS, 51GS) protection element that is configured to operate General Pickup. In addition, manual
closing of the circuit‑breaker is blocked when Hot Line is active. This can help to prevent unintended energi-
zation of a dead circuit whilst personnel are working nearby. Hot Line must be switched off before the
circuit‑breaker can be closed. Hot Line can be configured to be switched in or out by binary inputs, function
keys or by commands via the communications protocols. There are no other configurable options for Hot
Line. Lockout will prevent autoreclose.
NOTE
Autoreclose cannot be triggered by pickup or operation of other protection elements such as under/over-
voltage, frequency, thermal or negative sequence overcurrent.
Control Functions
7.3 79 Automatic Reclosing
422 Reyrolle 7SR5, Overcurrent Protection Device, Device Manual
C53000-G7040-C014-1, Edition 11.2019
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