3-29
CH 3/ Real Time Data
Section F
Harmonics
Overview
Harmonics
display
HDPQ Xplorer allows you to view voltage and current harmonics/interharmonics in
graphical or in tabular form. Harmonics are waveform distortion, steady-state
deviations from an ideal power frequency sinusoid and are characterized by the spectral
content of the waveform. Interharmonics are frequency components between the
harmonic frequencies. The IEC 61000-4-7 and IEEE 519 Standards dictate 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.
You 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
and IEEE 519. You 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 Table
: Harmmonic list gives a tabular 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). Harmonic table values
are displayed in order of ascending frequency, and can also be sorted in order of
descending magnitude.
Harmonic
screen and
function keys
Harmonic graph can be displayed by pressing Harmonics from the Real-Time Data
menu or by pressing the Harmonics real-time metering icon on the work area of the
Home Monitoring page. Note that the window defaults to a graphical spectrum display,
similar to sample screen shown below. Use the function keys at the bottom of the
screen to set up the harmonics graph/table.
Shop for Power Metering products online at:
1.877.766.5412
www.PowerMeterStore.com
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