Harmonic Analysis (Voltage Measurement) - Gossen MetraWatt METRAHIT ENERGY TRMS System Multimeter Operating Instructions Manual

Measurements: V/Hz/dB – PQ/

5.1.5 Harmonic Analysis (voltage measurement)

In the switch positions for the mains quality analysis
rent measurement (A) functions, harmonic analysis is performed
approximately once per second using 32 averaged sampling
values per mains period (adjustable to 16.7, 50, 60 or 400 Hz, see
section 6.4.6 on page 71).
FFT (fast Fourier transformation) makes oscillations up to the 15
harmonic available to this end. The RMS values of the fundamental
harmonic (HD 1) and the individual higher harmonics (HD 2
through 15), as well as total harmonic distortion (THD) are calcula-
ted. RMS values and harmonic components are displayed in each
case (RMS values relative to the RMS value of the fundamental
harmonic). Harmonic analysis is also available for current clamp
measurement.
Ð Set the rotary switch to PQ.
Ð Press the multifunction key FUNC | ENTER.
Ð Connect the measurement cables as you would for a voltage
measurement.
The main display shows total harmonic distortion as a percentage,
and the total RMS value of distortion appears at the right-hand
auxiliary display.
Ð The distortion components (main display) and the RMS values
of the individual harmonics (left-hand auxiliary display) can be
measured by pressing the
Ð The instrument is switched directly to a display of total har-
monic distortion after pressing the ZERO | ESC key.
36
– MHz/% – /nS/R
–
SL
and cur-
 scroll keys.

/ – Temp – /m – W/Wh – A/Hz/thd
Prerequisites
The results of harmonic analysis are only valid if the following
conditions are fulfilled:
• The fundamental frequency corresponds with the selected
fundamental frequency.
• Only significant harmonic components occur up to the 15
th
monic (made apparent by rapidly dropping RMS value compo-
nents up to the 15
• The AC TRMS value amounts to at least 5% of the measuring
range.
Additional Harmonic Analyses (current measurement)
For direct current measurement see section 5.8.1, for measure-
ment with current clamp sensor see section 5.8.2 and for measu-
rement with current clamp transformer see section 5.8.3.
th
harmonic).
GMC-I Messtechnik GmbH
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har-