I need to know whether there is an option where we can delay a clear alarm to i.e. the open alarm should not be closed immediately when a clear alarm arrives rather it is held back for 10-15 mins. prior to it being closed.
What's the reason behind that query? I need to understand it better to give you the best option. You can probably use an EventProcedure for this, but that would be on a per-alarm basis...
I am not aware of any functionality either globally or on an individual model to delay the clearing of an alarm. As noted by Christophe, this would have to be configured on a per event basis using either an event procedure or an event pair rule.