22 5 WHAT THE 2SX-SERIES SCANNER RECORDS
The Minute Histogram is also better for this analysis because it does not
run out of memory, and is always set for one minute averaging.
The current Minute Histogram shows average load current on a minute
basis. The maximum and average load currents are easily spotted on the
Histogram as the edge and the center of the current spread. Again, this
information is usually in the current Stripchart, but not as easy to see.
The cycle Histograms can also be used for voltage regulation problems and
load profiling, but the Minute Histograms can be easier to read since the fast
one-cycle events have been averaged out.
5.6 Energy Usage
The Energy Usage report shows the accumulated real, reactive, and apparent
power measured by the Scanner. The accumulated real power is energy, in
kilowatt-hours. The accumulated reactive and apparent powers are kilovar-
hours and kilovolt-amp-hours, respectively. These totals are for the entire
recordings session, and are only available on Scanners which can compute
power.
5.6.1 What’s Recorded
Each cycle, the real, reactive, and apparent power values are computed and
added to the running totals for the recording session. These values include
the effects of voltage and current harmonics. The accumulated powers are
totaled separately for each channel for a wye hookup. With a delta hookup,
the individual phase powers cannot be measured, only the total. In this case,
the three phase total real, reactive, and apparent power values are totaled and
reported.
Negative power values are included in the accumulation. For example, if
a load is both absorbing and generating power (at different times, of course),
the accumulated power will reflect it. A line that varies from leading to
lagging power factor may have a small accumulated reactive power reading,
even though at different times the actual reactive power flow was large. This
would happen if the negative vars accumulated during the periods of leading
power factor mostly cancelled the positive vars during the periods of lagging
power factor.
5.6.2 Typical Settings and Suggested Uses
There are no settings for the Energy Usage report. This report can be used
to measure energy consumption of a monitored load, or accumulated reactive
