Power Factor Setting

[Endura]

Does the Power Factor setting directly correlate to the Inverter Pnom limit or is it adjusted based on line losses & transformer losses as well?

For greater clarity:

Transformers and conductor systems (primarily long MV systems) change reactive power consumption within a PV plant so an inverter power factor setting would vary from the point of interconnection's Power Factor depending on the requirement (leading or lagging) and equipment/design of the PV plant.  

For performance modelling in PVsyst, should we be performing this load flow analysis externally and setting the Power Factor in PVsyst based on the requirement at the inverter?  Or does PVsyst perform some adjustments to account for reactive power within the PV plant?

For example, we have a plant with a long MV interconnection where the power factor at the grid point is 95% but the power factor at the inverter may be as low as 91% to deliver that PF to the grid.  In this case, would the recommendation be to use 91% in PVsyst or 95%?

[dtarin]

You would use 0.91 in PVsyst. If you run PF in PVsyst with 0.95 with a long MV run and a transformer, and you apply a grid limitation at the injection point, and set the grid limitation loss separate, you will still have an inverter operating at 0.95PF. Changing the length of the cable will not change this. You can confirm this by checking the maximum output power of the inverter.

If you do not account for grid limitation loss separately, then the inverter output will be reduced further. PVsyst takes the grid limit loss and adds it to the Il_Pmax loss. For example, I have a 3.6MW inverter, I set a 0.95PF, with MV AC, XFMR loss, and a grid limit of 3.0MW applied at injection point but do not check account as a separate loss, my maximum inverter output (for this particular case) is 3034kW. When I check account as a separate loss, my inverter output is ~3420kW, or 0.95PF.

[André Mermoud]

As it is implicitly involved in the post of DTarin, in the present time the AC losses  (Line + transformers) don't take the impedance into account; the calculation is purely resistive.  Implementing the lines impedances is on our roadmap, but we don't know when we will do that.

[Endura]

Thanks!  That is what I expected, will proceed on this basis.