Hello,

I'm passing almost 15 yrs in electronics & automation field. I suddenly found myself dealing with HIGH VOLTAGE transformers in huge steel mill. Transformer rating is about 125MVA.

Here are my questions:
How to check a transformer's health? How to ascertain its turn ratio? What is PI test and how to perform it? What is tan delta test and its significance? Take one example of 3MVA transformer.

Being very new to it I want to know more about the maintenance. I got some books about all these but I just thought to throw it to control.com to get some vital tips & information. I just want to get my basics correct as I have read all these during my engineering but not up to this scale. So just wanted to know if somebody could help me out.

Kindly help. Thank you.

Regards,
Sandeep

 

Hello Sandeep,

First you check the IR value as per Transformer voltage rating, Winding resistance, PI polarization index value with the help of High Voltage test set, Winding turn ratio can be test with the help of ratio Tester or Auto transformer. Check BDV test of tr. Oil, Moisture content, Acidity and DGA test. With the help of these tests you can know the Transformer Health.

Regards,

M.M.Batra

 

Hi sandeep,

If I am not wrong, are you talking about furnace transformer in steel mill? If yes, generally all the tests you are talking about are done during commissioning and later on these can be done on an annual basis.

But on a regular basis, the tests which are easy and can be done are to check the IR value of winding. Check the temperature trends on a regular basis for transformer oil and winding. For healthiness of transformer, one of the main factors is the cleanliness of insulators.

If more information is required, please reply again.