hi all
Few days we filtered the oil of our transformer, rating 33kV/1500V. This machine is using heating/vacuum for filtering the oil. But after the filtration when whe made DGA, we found the Oxygen and Nitrogen content have increased too much.The result shows big variation in all readings as below.

Before and after(ppm)
Hydrogen 7-------14
Oxygen 15000-----23000
Nitrogen 40000---66000
methane 7--------4
co 140-----------266
co2 960----------1200
acetylene 10-----5
ethylene 60------40
ethane 10--------5

These results are beyond my expectation.
Can someone understand what may be exact cause.

 

Paru, it appears that the before/after measurements may have been taken at different temperatures!

Regards, Phil Corso ([email protected])