Buried cable calculations.

[breaker12]

Where can I find a comprehensive guide to calculate buried cable sizes in conduit,between two transformers 13.8kV, range XFMR1-50MVA, X=25.4%, XFMR2-289MVA at 0.85pf, 1000ft apart and calculate V-drop.

 

[dpc]

We aren't mind readers:

Location in the world?
Applicable Codes and Standards?

Also, confirm xfmr2 is 289 MVA at 13.8 kV??

The 25.4% X for xfmr1 seems very suspicious also.

If you are in the US, get a copy of the National Electrical Code and also the IEEE Red Book.

 

[EPEngineer]

breaker 12
If you are in IEC world the applicable code would be IEC-287. Sometimes the clients are happy with cable sizing calculations based on current capacity for specific laying conditions and applying different de-rating factors which are clearly mentoined and explained in cable manufacturers' catalogues. However if a thermal dissipation calculation is required then you need to consult the relevant standards as mentioned above.

Volts drop is a part of de-rating calcuation. You calculate the maximum length of selected cable size for site conditions for a maximum allowable voltage drop which depends upon the application. A combined voltage drop of 5% is acceptable.

Hope this was helpful