Circuit Breaker - Siemens 7SR224 Technical Manual

7SR224 Argus Description of Operation
4.4

Circuit Breaker

This menu includes relay settings applicable to both manual close (MC) and autoreclose (AR) functionality.
CB Controls Latched
CB controls for closing and tripping can be latched i.e. until confirmation that the action has been completed i.e.
binary input is edge triggered when latched.
Close CB Delay
The Close CB Delay is applicable to manual CB close commands received through a Close CB binary input or
via the Control Menu. Operation of the 79 MC Close CB binary output is delayed by the Close CB Delay setting.
Close CB Pulse
The duration of the CB Close Pulse is settable to allow a range of CBs to be used. The Close pulse will be
terminated if any protection picks-up operates or a trip occurs. This is to prevent Close and Trip Command pulses
existing simultaneously. A 79 Close On Fault Output is given if a pick-up or trip operates during the Close Pulse.
This can be independently wired to Lockout.
'CB Failed To Open and CB Failed to Close features are used to confirm that a CB has not responded correctly to
each Trip and Close Command. If a CB fails to operate, the AR feature will go to lockout.
'79 CB Close Fail' is issued if the CB is not closed at the end of the close pulse, CB Close Pulse.
Reclaim Timer
The 'Reclaim time' will start each time a Close Pulse has timed out and the CB has closed.
Where a protection pickup is raised during the reclaim time the relay advances to the next part of the reclose
sequence.
The relay goes to the Lockout state if the CB is open at the end of the reclaim time or a protection operates during
the final reclaim time.
Blocked Close Delay
The close command may be delayed by a Block Close CB signal applied to a binary input. This causes the
feature to pause before it issues the CB close command and can be used, for example, to delay CB closure until
the CB energy has reached an acceptable level. If the Block signal has not been removed before the end of the
defined time, Blocked Close Delay, the relay will go to the lockout state.
Open CB Delay
The Open CB Delay setting is applicable to CB trip commands received through an Open CB binary input or via
the Control Menu. Operation of the Open CB binary output is delayed by the Open CB Delay setting.
Open CB Pulse
The duration of the CB open Command pulse is user settable to allow a range of CBs to be used.
CB Failed To Open is taken from the Circuit Breaker Failure Element.
CB Travel Alarm
The CB Open/CB Closed binary inputs are monitored. The relay goes to Lockout and an output can be given
where a 0/0 condition exists for longer than the CB Travel Alarm setting.
An instantaneous output is given for a 1/1 state.
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