Measurement Computing WavePort 312P rev.1.0 - Manual (Page 72)

9-4 Event Capture PowerVista/312 User’s Manual
• Monitored Harmonics: are the four user defined harmonics (from 1 to 50) that will be logged at the
same interval the Demand Logging is occurring at. Harmonics are calculated every half second and
maximized over the Demand Interval. These are 128 point single cycle harmonic decompositions.
• Link Plot Time Scales: when checked will link the Event Volt Plot and the Event Current Plot
windows so that when any panning or zooming is performed, the alternate partner plot will follow the
scaling. This is a horizontal axis link only.
• Update Rate: is the rate at which the Event Capture graphic windows are updated while monitoring.
During monitoring, only single cycles are plotted.
• Text View: allows the user to choose one of two views for the Event Trigger Data window. Either
trigger information or event extremes can be displayed.
• Plot View: allows the user to choose one of two views for the Event Capture graphic windows. Either
three phase quantities, or the extra input channels (V4 and E1) and neutral current can be displayed.
9.3 Event Capture Application
Capturing events is one aspect of determining the quality of power at a location. Total quality of power includes
harmonics, overall voltage regulation, and of course events as they are mapped into the categories of sags, swells,
transients, outages and interruptions. The Event / Demand Capture feature of EasyPower Measure delivers
monitoring for all of these areas with exception only to fast transients or impulses.
If the instrument is connected to PT and/or CT secondaries, then fast transients and impulses are not within the
bandwidth of the PTs and CTs and are thus not an issue. Transients on medium and high voltage systems also
have a frequency range that is dependent on the network impedances and mostly fall within the 128 point per
cycle resolution.
9.3.1 Trigger Table and Event Extremes
The Trigger Table and Event Extremes are supplied to the user for a complete indication of event trigger cause
and what the extreme peak and RMS conditions were for the event. For any event that is being browsed after
data collection, the trigger tabulation shows every trigger threshold that was activated for the event. This
information is essential in evaluating present trigger settings so that future data collection is effective and
efficient.
The Event Extremes supply three columns of information, where each column is for a single extreme. The
extremes supplied are:
• Peak: This is the absolute peak voltage or current for the captured event over the event duration. Both
positive and negative half cycles are evaluated. This value is always supplied as a positive number even
though the peak may have occurred on a negative half cycle.
• Min RMS: This is the minimum RMS voltage or current on a single cycle within the event over its
duration. For a sag, this will be the floor voltage.
• Max RMS: This is the maximum RMS voltage or current on a single cycle within the event over its
duration. For a swell, this will be the ceiling voltage.
9.3.2 Demand Log and Event Links
Each Demand Log includes time and date stamps for each data item. When the plot cursor is displayed (and in
Curve Values mode in the Demand Viewing Configuration), instead of a normal X Axis type value, the entire
date and time is displayed for each curve's digitized value.
Also, the demand log includes the first and last event that occurred during its interval. If Event Numbers with
Event Markers is selected in the Demand Viewing Configuration, vertical bars will be displayed to mark the