Power factor and solar energy systems

Discussion in 'Feedback and Suggestions' started by Gordon Howell, Jun 28, 2010.

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1. Gordon Howell Thread Starter Guest

Consider:
a) A house with a solar PV system on it is consuming 1000 W of real power and 400 VAr of reactive power from the grid and generating 0 W. Its power factor is 0.93, 93% or 22° at its service entrance.

b) The solar PV system generates power with a power factor of 1. If the PV system generates 500 W into the house, then the house service entrance is seeing 500 W of real power and the same 400 VAr of reactive power, and thus the electric utility company sees that house has a power factor of 78% and 39°.

c) If the solar PV system generates 1000 W, then the electric utility company sees that the house service entrance has a power factor of 0 or 90°.

d) If the solar PV system generates 1500 W, what is the power factor? The house has a net export of 500 W and it is still using 400 VAr. I would suggest that the power factor becomes negative, not leading or lagging, and that it would be -78% or -39°.

I have several year's worth of 15-minute data on my own PV house that shows this. I suggest that this applies to all electrical services that incorporate their own electricity generator.