A voltage sag is a reduction in RMS voltage (between 10 and 90 percent of nominal) that can last anywhere from 0.5 cycle up to 1 minute. Voltage sags are typically caused by loose connections, energizing a load that requires large current, or power system faults.
There are two ways to find voltage sag events using ProVision, visually scan an RMS Voltage and Current graph for dips in the voltage or use the “Voltage Out of Bounds” feature found in the Report menu. The latter method is more efficient and tends to provide excellent results. For a given recording, ProVision will search and highlight each voltage event outside of the specified bounds.
Analyzing voltage sags using Provision is straightforward once you know what tools to use to get the job done. Using voltage out of bounds reports to find voltage sags is a quick and accurate way to scan recordings that may contain hours or days of information.
If further analysis of sag events is necessary RMS Voltage and Current stripcharts provide time averaged values allowing an overview of the sag event. For more detailed analysis of sags a waveform capture shows the full detail for the events in question...
This white paper includes: