Standard and high-speed alarms
Standard alarm
Standard alarms have a detection rate of once every one second.
High-speed alarm
High-speed alarms have a detection rate of once every half-cycle.
3-phase alarms
Alarms on 3-phase systems are evaluated per phase and reported for each phase.
Some alarms, such as the sag/swell alarm, are evaluated per phase, but reported as a single alarm: Each of the three phases are evaluated for the setpoint condition individually, but there is only one alarm generated. The alarm pickup occurs when the first phase exceeds the alarm pickup magnitude for the pickup time delay. The alarm is active as long as any phase remains in an alarm state. The alarm dropout occurs when the last phase drops below the dropout magnitude for the dropout time delay.