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PQM POWER QUALITY METER – INSTRUCTION MANUAL
POWER ANALYSIS
CHAPTER 6: SOFTWARE
6.6.2
Harmonic
Analysis
Non-linear loads such as variable speed drives, computers, and electronic ballasts can
cause harmonics which may lead to problems such as nuisance breaker tripping,
telephone interference, transformer, capacitor or motor overheating. For fault diagnosis
such as detecting undersized neutral wiring, need for a harmonic rated transformer or
effectiveness of harmonic filters; details of the harmonic spectrum are useful and available
with the PQM and EnerVista PQM Setup.
EnerVista PQM Setup can perform a harmonic analysis on any of the four current inputs or
any of the three voltage inputs by placing the PQM in a high speed sampling mode (256
samples/cycle) where it will sample one cycle of the user defined parameter. EnerVista
PQM Setup then takes this data and performs a FFT (Fast Fourier Transform) to extract the
harmonic information. The harmonic analysis feature is implemented into EnerVista PQM
Setup as shown below.
Z
Select the
Actual > Power Analysis > Harmonic Analysis
menu
item.
Z
Select the desired output type:
Waveform
or
Spectrum
format.
Z
Select
Spectrum
EnerVista PQM Setup to display Harmonic
Analysis Spectrum window including the harmonic spectrum up to
and including the 62nd harmonic.
Z
Select the trigger parameter from the
Select Trigger
box and
press
Trigger
to display the harmonic spectrum.
The window includes details of the currently selected harmonic and other harmonic
analysis related data (for example, THD, K Factor, etc.).
Z
Select
Read Last Trigger From Device
to load previous acquired
spectra from the PQM.