Why can one not see a duration time for a sag event?
Issue:
A sag event has occurred on an ION or PowerLogic meter, but the duration does not display through a data log viewer.
Product Line:
Power Monitoring Expert 7.2
Power Monitoring Expert 8.x
Power Monitoring Expert 9.x
Power Monitoring Expert 2021
Power Monitoring Expert 2022
Power Monitoring Expert 2023
Power Monitoring Expert 2024
Environment:
Vista
Cause:
All meter power quality events (sag, swells, transients) have two separate 'Disturbance Start' and 'Disturbance End' timestamps. PME uses the difference between these two to calculate the duration. During a sag event, if a meter's control power is wired in parallel to the voltage inputs this can cause the meter to only register the 'Disturbance Start' event.
Resolution:
If a duration time stamp is needed, the meter should be wired with separate control power from the voltage inputs such as a battery backup. This will ensure that if the voltage inputs go to zero, the meter will remain powered to capture both the start and end events.