Excitation Current

[Melco001]

What is the Excitation current testing criterion of acceptance for a Step-up 13.8 kV to 115 kV transformer 45MVA.

 

[TurbineGen]

We need more information. What is the construction? What manufacturer? Is this a GSU transformer? Did you check the manual? If you don't have the transformer manual available, you might try Doble to see what their pass/fail criteria are for a similar unit.

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If it is broken, fix it. If it isn't broken, I'll soon fix that.

 

[pwrengrds]

Typical readings will be 2 readings simlar, and a third lower. The lower reading will be the center phase. The current value (mAmps) will depend on the voltage applied, typically 10kV. You should be able to look at the transformer factory test report and get an idea what it should be.

 

[Melco001]

Ok thanks so much, I'll check those records from the quality dossier of the GSU transformer, if I have that commissioning books.

 

[Elmir]

The configuration of the transformer and test method applied will determine the pattern of excitation currents measured.

Pattern of two higher and similar currents and one lower is typical for 3 phase units.

There is an alternate test connection used on DELTA connections that will yield two lower similar and one higher result.

Similar readings are usually within 5% of each other and the lower current is usally 65% - 95% of the higher value.

Always refer to the manufacturer data first if available.