Power Factor Measurements - Source

A question on power factor— is it recording displacement power factor, factoring in harmonics, or just inductive power factor? I ask because while my load measurements are rational (>0.85), my utility measurement on one phase records a very low PF - ~0.46, and a pretty significant daily VARh.

It isn’t something I really am too concerned about— it is residential service— but I was trying to compare measurements with my utility bill and the kWh numbers appear to be a bit off. We have PV, FWIW.

I guess the other question is I might have set something up incorrectly that causes the issue, but I am not sure how to actually ask that.

The PF is calculated as Watts/VA. If you are looking at the PF of an output that combines several inputs, it’s (total Watts/(total VA).

It sounds as though you may have a problem with one of your mains CTs. If you have the clamp-on type, there may still be a protective paper between the jaws. That usually causes low PF and lower power measurements.

VAR is calculated by the Pythagorean theorem using Watts and VA. It should be accurate. VARh on the other hand is not very accurate when measured over long periods. The integration over a day as computed in Graph+ is pretty good, but longer periods are not viable. You would need to use query to extract high resolution VAR and integrate in a spreadsheet.

Solar should not be an issue. Inverters typically produce power at Unity PF, so if there is a time when you exported most of the generated power and you main is not close to unity, that would indicate a CT issue. I’d recommend removing it, inspecting the mating core surfaces, and reinstalling.

Thanks!! I’ll have to get the clamp-on CT checked. Paper sounds like the likely culprit.