Power limitation in both, grid and at inverter level

[jonipa]

Hello!

I am currently trying to understand how to manage the case in which there are two power limitations in my PV Plant: Grid and inverter limitation.

PVSyst seems to only allow the limitation either at inverter or at injection point level. At least in the "energy management" section.

Is ther a way to apply both? Maybe applying inverter active power limitation directly on inverter .ond file? What is the right way of doing it?

Thank you for your feedback!

[jonipa]

Maybe @dtarin could give us some light on how to proceed?

[Michele Oliosi]

Actually PVsyst will apply both by default. The nominal active power limitation by the inverter is automatic.
The question "limitation applied at" "inverter" or "injection point" refers only to the supplementary grid limitation. The difference is whether or not the losses between inverters and injection point should be taken into account to raise the limitation a little bit at the level of inverters.

[jonipa]

Thank you Michele,

So what if I have a limitation of, for example, 46MW at injection point and also a 47 MW limitation at inverter level? How should it be managed when inputing it into PVSyst?

[Michele Oliosi]

Ah I see, if both are different from the nominal power of your inverters you can either:

• modify the inverter Pnom
• just set the most stringent of both (it would be very unusual if this changes throughout the year I think?)

[jonipa]

As beforehand I don't know which one is more restrictive, guess the better option is to modify inverter's output power.

It should be applied to Pnom as weel as Pmax, right?

[dtarin]

Set to both nominal and max. Generally a limitation at the injection point supersedes, or is more common, than a limitation at the inverter. Setting an inverter limit means the inverters are being curtailed, and are being modified by the inverter manufacturer with an adjusted nameplate (they will be providing a letter to certify the new nameplate, etc.). It all depends on your project requirements, what type of installation, grid requirements, etc. 

 

Edited November 22, 2022 by dtarin

[dtarin]

To do both simultaneously, 1) modify the OND file to the inverter limit, 2) set grid limit to limit at a second value at the injection point, account as a separate loss. You can also do all of this post-PVsyst without modifying the OND file, but you will need to account for the AC losses separately as well.