Transformer Losses

You can get all the transformer full load and no load losses from the transformer manufacture. They got all the transformer data's. We cannot calculate the losses as we don't have any data's of your transformer.

Dear sir,

As the data from manufacturer or test certificate is not available ,that's why I need an approximate idea.The transformer is oil cooles .

<...not available...>

That's why the manufacturer needs to be contacted direct. There is a much better chance of obtaining the data direct and it will be faster, which may be an issue.

Googling the manufacturers' telephone numbers is the next step.

What you can do is to estimated that your transformer No Load loss will be about 1.3% of your total transformer KVA and with Full load loss will be 1.8 to 2% of your transformer KVA. It just an estimation of the losses.

We need to have your transformer impedance's to calculate the losses but since you don't have these data's, we can just assume the average losses.