In the transformer differential protection , what is the allowable delay of the diff protection to avoid false trip resulted by the inrush current?

Dear Sir, Differential by any mean is the backup of Over Current,Earth Fault,Voltage Controlled Overcurrent, NPS,Under Voltage in any Phas & Many other protection. But the the most important problem is when interturn fault occured in Transformer winding( Winding is more closer with Transformer Core).If inter turn fault occured transformer breaker should be tripped within150-200 miliseconds to prevent damage.2nd to on a breaker we requir80 miliseconds, it is better to juge transformer charging Inrush Current and also charging time, by calculating short Ckt & load flow studies for proper co-ordination. Now a days their are Siemens make relay7SR242.Their is an option to sence the relay that Differential Tripping is Due to Fault, but not in case of Charging, by activating Inrush On( to block inrush current tripping.