Thanks for your reply, the trip coil of the lock out relay connected in series with the protection relay contact which activates the trip command also prevents the auto reclosing .But I want to know current discharge were,and the type of fault you mentioned.The lock our relay has such a large magnetic that it is not likely to operate due to the low level current that might be discharged when a fault first occurs. This provides time for the other protective devices to perform their function.
Thanks for your reply, but apart from multifunction realy,there are other protection has used in some systems such as ITH protection in corporate with pressure flap to prevent and escape heat while flap will operate ,its limit switch will give command to LOCKOUT relay to isolate entire bus,or SWITCHGEAR during the fault.Which is not incorporate with multifunction relay.IF you use a lockout relay practically everyone uses Electroswitch. The issue is it adds generally a one cycle delay to trip times. With today’s concerns over arc flash among other things and tighter coordination adding a lockout relay has become less popular and generally unnecessary. A good multifunction relay implements lockout in software.
