MI 2883 Energy Master
Operating the instrument
44
3.8 Harmonics / interharmonics
Harmonics presents voltage and current signals as a sum of sinusoids of power
frequency and its integer multiples. Sinusoidal wave with frequency k-times higher than
fundamental (k is an integer) is called harmonic wave and is denoted with amplitude
and a phase shift (phase angle) to a fundamental frequency signal. If a signal
decomposition with Fourier transformation results with presence of a frequency that is
not integer multiple of fundamental, this frequency is called interharmonic frequency and
component with such frequency is called interharmonic. See 5.1.7 for details.
3.8.1 Meter
By entering HARMONICS option from Measurements submenu the tabular
HARMONICS (METER) screen is shown
(see figure below)
. In this screens voltage and
current harmonics or interharmonics and THD are shown.
Figure 3.30: Harmonics and interharmonics (METER) screens
Description of symbols and abbreviations used in METER screens are shown in table
below.
Table 3.22: Instrument screen symbols and abbreviations
RMS
RMS voltage / current value
THD
Total voltage / current harmonic distortion THD
U
and THD
I
in % of
fundamental voltage / current harmonic or in RMS V, A.
k
k-factor (unit-less) indicates the amount of harmonics that load
generate
DC
Voltage or current DC component in % of fundamental voltage /
current harmonic or in RMS V, A.
h1 … h50
n-th harmonic voltage Uh
n
or current Ih
n
component in % of
fundamental voltage / current harmonic or in RMS V, A.
ih0 … ih50
n-th interharmonic voltage Uih
n
or current Iih
n
component in % of
fundamental voltage / current harmonic or in RMS V, A.
Table 3.23: Keys in Harmonics / interharmonics (METER) screens
HOLD
Holds measurement on display. Hold clock time will be
displayed in the right top corner.
RUN
Runs held measurement.
F1
