A dead bus is a busbar that has lost all voltage. Control logic and operators treat it as a special case, because a breaker may close onto a dead bus without the synchronising checks needed when both sides are live. Black-start procedures, generator start-up and auto-reclose schemes all include dead-bus or dead-line conditions, confirmed by undervoltage elements, before the first breaker closes.
Confirm dead bus on the 11 kV, then close the diesel incomer on dead-bus permissive and start picking up load.
Also heard as
- dead bar
- dead busbar
Related terms
Bus
Rigid conductor or common node in a substation or switchboard where several circuits connect and share power.
Black start
Restarting a power system from total shutdown using generators that can start without any outside supply.
Auto-reclose
Automatic closing of a breaker shortly after a fault trip, restoring supply when the fault was only transient.
Dead
Isolated from every source, proven free of voltage and safe to work on.