A flag, also called a target, is the mechanical or LED indicator on a protection relay that stays set after an operation to show which element tripped, such as A-phase instantaneous or earth fault. Operators record every flag before resetting, because flags are the first evidence of fault type and location. As a verb, a relay that flagged has shown an operation.
Write down every flag on the panel before you reset anything, I want to know whether the 50 or the 51 flagged.
Also heard as
- target
Related terms
Protection relay
Device that watches currents and voltages and orders a circuit breaker to trip when it detects a fault.
86 relay
Lockout relay that latches after a serious trip and holds breakers open until someone resets it by hand.
Trip
To open a circuit breaker automatically through its protection, or to order a breaker open by command.