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Transformers No load current and losses

Transformers No load current and losses

Hello everybody,

I would like to receive some feedback related to values of no load current and no load losses for three phase transformers of 17, 40 and 50 MVA's
They work in several voltage levels:
50 MVA 115/23   kV
40 MVA 23/ 13.8 kV
17 MVA 13.8/4.16kV

If you could provide some typical data or any reference to look for, it will be great!

I thank you in advance!

RE: Transformers No load current and losses

IEEE-141, AKA The Red Book.

RE: Transformers No load current and losses

Thank you
Bu, there will be some other technical reference for those values?

Best Regards

RE: Transformers No load current and losses

The vintage of the unit is important.You  are referring to today's transformers  or yesterday's? Values will differ.

RE: Transformers No load current and losses


I am not sure if the units are old or new ones, however, because of the network features, I may think as old ones and in that way, I guess values should be greater and force us to a conservative situation.

If you could provide us some data I will thank you!

RE: Transformers No load current and losses

The Westinghouse T&D Handbook has some typical loss and magnetizing current data for power transformers.  This information is somewhat dated.

There are wide variations in transformer losses and no load (magnetizing) current.  Most utilities now evaluate losses during the procurment process; this has resulted in lower losses.  Manufacturers will design the transformers to optimize the evaluated cost of the units.

RE: Transformers No load current and losses

In todays transformers the no-load loss will be 0.05- 0.08%(50-20 MVA) and excitation current around 0.1 % of full load current.In old trfs it can be double( losses) and 2-3 times (no-load current)

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