Application Note

Application Note
F r o m t h e F l u k e D i g i t a l L i b r a r y @ w w w . f l u k e . c o m / l i b r a r y
Power quality recording
and analysis: Techniques
and applications
Hooking up a power quality recorder and taking
days’ worth of data can give you a rich picture
of your power. In this article we’ll talk about the
various recording techniques available in power
loggers and recorders—understanding the tools
and techniques you have available will be key to
your strategy. What should you be looking for?
And when does recording make sense?
To really know your power, ideally,
you’d want to look at every line
cycle to see even the smallest
changes. However, since our power
swings through more than four
million cycles per day, it’s impracti-
cal to look at tiny changes—and
often unnecessary. Few loads even
notice occasional voltage dips of
one or two cycles.
How long you record depends
somewhat on the rhythm of your
building. If you are working on a
typical commercial or light indus-
trial building, then a week is long
enough for a building to go through
its normal cycle. If you are work-
ing in a plant that runs special
equipment only periodically (say
a furnace that runs only monthly),
you’ll need to be sensitive to the
timing of these loads.
Different recording techniques
have been developed to look at
small changes over relatively long
time periods. Many instruments
combine several techniques to
improve their coverage. We’ll
describe the common techniques
and some of their pros and cons.
By understanding the different
techniques. you’ll be better able to
choose an appropriate tool for the
job at hand.
Setting up a Fluke 1735 Power Logger at the service entrance for a
30-day load study.
Recording techniques