Heat load calculation for transformers

Hi,

As a rule of thumb the heat dissipation will be a function of the MCR ( Maximum Continuous Rating) and the overall efficiency of 98% at a pf of 0.98. This will suggest something in the order of 2kW per 100kW load. There is a manufcturers' losses curve usually available for these products.

You should remember that there remains a standing loss value even if the transformer is completely idle as this represents the iron loss.

It is a pity to see A/C being used to cool a transformer as you will have to add these incurred parasitic losses to the inefficiencies of the installation. Also remember what will happen when the A/C unit falls over do you have to add a stand-by unit just in case? Far better to have the beast naturally cooled all round and avoid all these added life time costs and additional maintenance liabilities.

hope all goes well.

Ok I have a issue figuring out the heat load for some transformers, Their 12470 to 4160 V the 4160 has an amp rating of 270 and the 12470 amp rating is 123. Some help with this calculation would be helpful.