Disired power value

[khaoula.rahrah]

Hi PvSyst group !

I want to understand why when I enter the disired power value of my system a value =5kwp and when I run the simulation I get a simulation report where the disered power value is changed to 7kwp!what is the reason for this change ?
Is this normal? if not, what should I do? 
Please help me !

[Hizir Apaydin]

Dear khaoula.rahrah,

In the system definition window, PVsyst will guide you to select the number of modules in serie and the number of string according to the choosen desired power value, the PV module type and the inverter with a certain tolerance.

In your project, you have selected modules of 500Wp power on 2 strings of 7 modules. So the nominal power is 500*2*7 = 7000wp.

You can see this in the system summary section:

You can manually adjust the number of modules in order to be as close as possible to 5000wp. 

Selecting 5 modules in serie will give you the desired nominal power: 500*2*5= 5000wp

It is not always possible to have a nominal power equal to the desired power as it depends on the PV module nominal power, the inverter power and operating voltages

Regards.

[khaoula.rahrah]

Hello PvSyst team 

Thank you for your valuable response,

I went back to the same data of a scientific paper that requires 5 kW of power desired and the same quality of panel and inverter.
But when I select 5 panels in a series, I get this error (In Screen shot), so when I wanted to solve this error, I had to have 7 panels in a series.

What should I do in this case, provided that I do not change the quality of the panels and inverter and maintain the same characteristics ?

My best regards 

 

Edited May 21 by khaoula.rahrah

[Linda Thoren]

You have chosen a 7.0 kW inverter, and panels with a nominal power of 5.0kW, thus the inverter is a bit oversized. With an orange warning you can still run the simulation.

Please look at the following video tutorial for more information about the sizing:

Kind regards