SATEC SA300 ezPAC Operation Manual - Manual (Page 148)

Chapter 14 Viewing Log Files Viewing Waveforms
148 SA300 Substation Automation Unit
A spectrum is calculated over four cycles of the waveform beginning from the point
where the left marker line is located in the open waveform view. If both waveform
views are open, PAS gives the priority to the overlapped waveform view.
The order of the highest displayed harmonic component is equal to the half sampling
rate at which the waveforms are sampled minus one. If the waveform was sampled at
a rate of 128 samples per cycle, 63 harmonics are available. With 32 samples per
cycle, only 15 harmonics are calculated, while others will be zeros.
PAS can give you indication on whether harmonic levels in the sampled waveforms
exceed compliance limits defined by the power quality standards or local regulations.
To review or change harmonic limits:
1. Click on the spectrum window with the right mouse button and
select “Limits…”.
2. Select a harmonics standard, or select “Custom” and specify your
own harmonic limits.
3. Check the Enabled box to visualize harmonic faults on the
spectrum graph and in harmonic tables.
Harmonics that exceed selected compliance levels are colored in red on the graph
and in the tables.