Cable loss DC calculation

[Andreas]

Hello,

 

We have a internal discussion about how to calculate DC cables. 

I have been told that it its 2 way (go and return) including the extra lenght of the connection cables.

My colleague thinks it is one way including modules. 

 

In PV-Sol there is been written 1x go and return.

What length must i put in with a 100mtr from inverter to module to calculate te totall loss.

is it

(a) 100 + connection cables modules. ±140mtr

(b) 100 + connection cables and return ±260mtr

[developer_mh]

Hi Andreas,

if you have 100m distance between the inverter and the modules, you have to enter 200m cable length go-and-return, 100m for the (+) cable and 100m for the (-) cable. Often, the (+) cable and the (-) cable do not have the same length due to the conditions at the installation location, so we decided to have the user just put in the total length.

The length of the module cables must not be included in the DC cabling length, as these are already taken into account in the PV module datasheet. The electrical properties of the PV modules are always measured at the end of the module cables, so the resistance of the module cables is already included.

Hope that helps, kind regards,

Martin

[Soheil]

Hi Based on this conversation, how accurate is the DC cable loss calculation in the PVSOL software, when doing it manually or using external software, there is a big difference between what PVSOL is showing as the loss and what is calculated. (PVSOL seems to show a lower value), I want to make sure that I use of this option can be accurate enough to any standards. 

[developer_fw]

Hello Soheil

Sorry for the late answer, but your question has been lost.

On 6/29/2023 at 2:25 PM, Soheil said:

there is a big difference between what PVSOL is showing as the loss and what is calculated. (PVSOL seems to show a lower value), I want to make sure that I use of this option can be accurate enough to any standards.

Could you give examples? Could you send a .pvprj file plus a calculation that you made for us to analyse any differences? You could send the files via private message here in the forum.

Thank you in advance and kind regards
Frederik