Difference between Pnom in medium voltage transformer between simulation and reports.

[AlvaroRuiz]

Good morning I have a question regarding a simulation as seen in the photos I include three medium voltage transformers per sheet with a Pnom of 5.3 MVA, however in the report the sum of the power of the three transformers is not 3x5.3 = 15.9 MVA but in reports is 14.27 MVA.

 

 

 

[André Mermoud]

Please carefully read the report:

- on the left you have the transformer characteristics, with a nominal power of 5.3 MVA.

- on the right you have the operating conditions, showing the "Nominal power at STC. This is the reference power for the wiring loss estimations in percentage.

[AlvaroRuiz]

Good morning again;

The value of 5300 MVA is referred to the STC of the MV transformers so it is not necessary a change to STC because they are already the conditions included in the data sheet. 

What configuration should I choose to maintain these values of 5.3 MVA in STC? 

Thank you very much for your help. 

[André Mermoud]

In PVsyst, all the AC losses expressed as percentages are referenced to a same power.

This power may be either the STC power of the PV array, or the PNom output limit of the inverters.  You can modify this choice in the Project's settings (button at top of the project's dialog).

You can have a look on the help  "Project design > Array and system losses > AC ohmic losses: reference power".