MPP adaptation differences

[RicardoM]

Good morning dear developers,

I designed a project and then rearranged some of the modules among different roofs (always with the same orientation and inclination), keeping the same total number of modules, same number of inverters and same number of modules per string. Besides the different layout (which influenced cable distances, longer in the secod simulation) I also decreased some cable sections.

        

Comparing both simulations, the 2nd one is 2% lower in total energy output but cable losses, although larger, do not account for that. The main difference I see is what is referred to as "Adaptación MPP" in Spanish, which goes from 2,00% to 4,00%. As both results are quite exact and the second is exactly double, I was wondering, where does that come from? Have I perhaps inadvertantly set that parameter somewhere, so that it is not a product of the simulation but rather a design choice, in the line of soiling losses? If so, where do I change it? If not, what influences it?

Please see below an excerpt of the energy balance of both simulations (in the same order):

Thanks for your time, kind regards,

Ricardo

[developer_mh]

Hi Ricardo,

could you provide the two project files, please? You can send them with a private message here in the forum.

Thanks and kind regards,

Martin

[developer_mh]

Hi Ricardo,

thanks for the files. The MPP adaptation losses come from the inverter parameters here:

In one project, you use the SUN2000-40KTL-US with 96%, in the other project, it is the SUN2000-40KTL (without -US), with 98% MPP efficiency. That is where the difference in the energy balance comes from.

And then, these values seem quite low to me. At least in the higher range of >20% the MPP converting effiency should be higher than 96%.

Hope that helps, kind regards,

Martin

[RicardoM]

Hi Martin,

It does help, thanks. My bad for inadvertently choosing a different inverter when both should have been the same, but this leads me in another direction: these are values that I don't see in the product datasheet (please find it attached), so as the inverter did not exist in the PVSOL database, when I created it I must have left the default values, which apparently are more conservative than actual values. 

Would you say those actual values should be 98, 99%, higher...?

Thanks and regards,

Ricardo

 

SUN2000-40KTL-US Español.pdf

[developer_mh]

Hi Ricardo,

in situations where you want to create a database product that is not officially available, I would recommend to start with a copy of an existing product of the same manufacturer that is as close as possible to the product you want to enter. For example, from the same product line or so.

In this case here, candidates are the SUN2000-36KTL and the SUN2000-50KTL. I would suggest that you take the missing values of the MPP efficiency from them. They are a bit different though, but most of the times, also in other Huawei inverters, the values 99.8 and 99.95% seem to prevail.

Kind regards,

Martin

[RicardoM]

Hi Martin,

Thanks, I will do that in the future.

Kind regards,

Ricardo