| Harmonics Analysis Option [HAO] allows
PowerSight to do detailed harmonic analysis of voltage and current.
When this option is purchased:
- Our PowerSight Manager software will perform harmonic analysis
of waveforms to the 50th harmonic and present the results as
either a table, including RMS amplitude and phase angle, or
graphically as a bar chart. Either presentation may be printed
out for reports.
- THD of voltages and currents can be automatically calculated
and added to the data log (using the advanced data logging feature)
for later graphing and analysis.
- THD snapshots taken on PowerSight can be broken down into
percent magnitudes (relative to the fundamental frequency) and
displayed on the unit (using the “More” key).
- K factor measurements will be displayed by PSM when viewing
tabular results.
The Importance of Harmonic Analysis
One of the key areas of interest in analyzing power quality is
harmonic analysis. A distorted current consists of a current of
the fundamental frequency (usually 50Hz or 60Hz or 400Hz) and
other currents at frequencies that are multiples of the fundamental.
The heating effect of higher frequencies is much greater than
for lower frequencies. Therefore, excessive harmonic currents
can overheat cables or distribution transformers (K factor is
a measurement of this effect). In addition, harmonic currents
do not tend to fully cancel out, which can leave large currents
flowing in a neutral cable, possibly beyond the rating of the
cable. In most areas, utilities are under regulation to provide
voltage with no more than a few per cent THD (total harmonic distortion). |
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