[RE-wrenches] active vs apparent power readings with solar

[August Goers]

Hi Wrenches,

We have a residential site with grid tied solar where there is an
electrician involved who has gotten into taking site readings and thinks
there is a power factor problem. My gut on it is that there is some sort of
measurement reading error, and that the power factor should be around 1.

The electrician is using a Fluke 3540FC power monitor and has provided a
spreadsheet comparing active power to apparent power and calculating power
factor. See below (you might have to open the image and zoom in to read
it). This measurement was taken with a PV system running, presumably
sending some power back to the grid.  Note that the phase B active power
measurement is negative (PV exporting to grid) and that the apparent power
is positive. This nets in a power factor that is crazy low of 0.05.

Does anyone have experience about whether a meter like this can properly
measure these readings - maybe there is a setting error or it can't deal
with negative readings?

[image: image.png]

Best,

August
Luminalt
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