3-12
Overview
Section C
Harmonics
Overview
Harmonics
display
The Energy Platform allows users to view voltage and current harmonics/
interharmonics in graphical or in list form. Harmonics are waveform distortion, a
steady-state deviation from an ideal power frequency sinusoid and is characterized by
the spectral content of the waveform. Interharmonics are frequency components
between the harmonic frequencies. The IEC 61000-4-7 Standard dictates that harmonic
analysis is done using a synchronous window of 10 cycles for 50 Hz, or 12 cycles for
60 Hz. This results in bins which are nominally 5 Hz wide. The actual width of the bins
is equal to the actual frequency divided by 10 if the nominal frequency is 50 Hz, and 12
if 60 Hz. For example, if actually operating at 49.9 Hz, the bin is 4.99 Hz, but is
labelled “5 Hz” as specified by the standard.
Use the respective touch screen buttons to display the next Channel (Channels A, B, C,
D) and the next Parameter (V, I, W) of harmonic data. The number of harmonics/
interharmonics displayed is up to the 60th. Summary values of odd, even and total
distortion are displayed. A summary of harmonic distortion as well as interharmonic
distortion values per phase/parameter are also available on display.
Users can determine the number or range of harmonic frequencies to trend and view in
detail. There is also the option to select how to plot harmonic/interharmonic data and
specify the units of measure by which harmonic data is calculated.
Harmonic Graph: Harmonics are measured in accordance with IEC 61000-4-7 Class 1.
Users can choose the unit of measure by which harmonic data is calculated and
graphed, based on a Percentage of the fundamental value or in Engineering units (volts
and amps). Frequency components of harmonic graphs can be displayed either in Hertz
or in Harmonic Number. The graphs can be zoomed and rescaled.
Harmonic List: The list gives a textual display of the following for each of the
measured values: frequency and harmonic number; magnitude in Engineering units and
percent of fundamental; phase in degrees (for harmonics only). This list is displayed in
order of ascending frequency, and can also be sorted in order of descending magnitude.
In this section
The following topics are covered in this section.
Topic
See Page
Harmonic Graph
3-13
Harmonic Detail
3-14
Harmonic Options
3-15
Harmonic List
3-17
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www.
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.ca
