Modelling of Transformers for Power system studies 3

[KojoSincal]

In modelling techniques for power system analysis. Considering the ONAN and ONAF ratings for a transformer; which rating should be considered as the Base MVA for p.u unitization?

 

[crshears]

My former employing utility always used the full nameplate [maximum continuous] MVA rating.

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[wcaseyharman]

The transformer nameplate should tell you. Most I’ve seen use the self cooled ONAN value, but I’ve come across a couple at my company that use the force cooled maximum ONAF values.

 

[prc]

The maximum rating is used in the IEC world as the pu base; the self-cooled rating is used in the IEEE world. In IEEE World impedance etc are also expressed on ONAN base,