Cable size issue

[Owais Moghal]

Hello Support, 

I'm using 3x Huawei SUN2000-100KTL-M1 400V in my design but which should be 300kac & it shows correctly in the design section but when I calculate cable losses the PaC increases to 339KW. Because of this minimum cable size  400mm2 is calculated whereas according to my calculation, 300mm2 can be installed. The PAN file also looks good but not sure.

 

[André Mermoud]

When  defining the AC losses, the loss percentage is proportional to a specified reference power. 

Now this reference power may be either the POut(AC) when the system is working at STC,  or the maximum output power PNom of the inverters. This choice may be done in the project's parameters.

See the Help   https://www.pvsyst.com/help/ac_ohmic_losses_ref_power.htm

In your case, the  "STC: Pac = 339 kW"  means that the reference power  has been chosen as the Pac when the system is running at STC  (Nominal PV power = 346 kWp, multiplied by the inverter efficiency).

NB: If you change this reference, the relative ohmic loss [%] will change, but not the absolute (real) energy loss in [kW].

NB: PVsyst proposes a cable section, but you may obviously modify this choice.