17 5.3 Daily Profiles
downloaded at any time later, knowing that the beginning of the recording
session is locked in memory, and will not be overwritten. Other users always
download the Scanner before it fills up Stripchart memory, which make the
Wrap-Around setting irrelevant. The choice depends on how the Scanner will
be used. The factory default setting is for Wrap-Around to be enabled.
The third Stripchart setting is which Stripcharts are enabled. For voltage-
only Scanners, there is no choice: a voltage Stripchart is always recorded. For
Scanners that can record current, the current Stripchart can be turned off to
extend the recording time of the voltage Stripchart. It is usually better to
increase the Interval time instead of disabling current to get more recording
time. For the ViP Scanner, there are many more Stripcharts to enable or
disable. The choice depends on what information is needed. If a power factor
study is being performed, for example, turn on power factor, and possibly
apparent power and displacement power factor. If a power quality problem
is present, only voltage and current may be necessary, although adding Total
Harmonic Distortion (THD) may be useful to see if harmonics are present.
The total recording time is shown by Winscan as Stripcharts are enabled and
disabled during the Scanner setup. Another method to increase Stripchart
memory is to reduce the number of recorded channels. If only three channels
are needed on the ViP, changing the number of channels from four to three
gives 25% more recording time.
For quantities such as power factor, phase angle, THD, etc. often the
average is much more important than the one-cycle max and mins. The max
and min traces on the graph may be turned off so that they don’t obscure the
average trace.
5.3 Daily Profiles
The Daily Profiles are used to spot daily trends in voltage, current, power
factor, etc. The entire recording session is combined to form the “average”
24-hour day, which is plotted on a graph like a stripchart. Power quality issues
are usually not addressed with Daily Profiles (except perhaps consistently low
or high line voltage or harmonic distortion). Rather, average line conditions
such as regulation voltage, load current, etc. are profiled.
5.3.1 What’s Recorded
Each measured quantity has only one Daily Profile per channel in a recording
session. For example, there are two voltage Daily Profiles in a recording
session, one per channel. The Profile is averaged over the entire recording
session. This average is created by dividing the 24-hour day into 96 time
