Transformer Losses

[Michalis Angeli]

I would like to ask, about Medium Voltage lines length.

In my case, i have 450 meters distance between Substation to injection point (MV). In this dialog, as you can see below, should I define in Average MV lines length, 150 m because i have 3 phases or 450 m ? 

[André Mermoud]

This frame  "Medium Voltage line" is supposed to treat the line from the output of this MV transformer to the injection.

If you have 3 MV transformers, and one only connexion to the injection, the easiest way is to use the same length and a third of the section of the real line.

NB: The objective is to evaluate the resistance of the full circuit, as seen from each MV transformer. If you have more complex circuits, you should  calculate the global resistances of all your circuits by yourself,  and define sections/length corresponding to your external calculation.