Dissolved Gas Analysis Results interpretation

Which stage alarmed?

What was analysis baseline?

When your transformer trigger the bucholz relay, you have to shut down your transformer until future test has to be conducted. From your transformer oil results, your Hydrogen (H2) level with 28ppm is high not to mention your other gases, Oxygen with 173831 ppm and the Nitrogen 593952 ppm. What about the moisture content of your transformer oil?. I wouldn't find it in your table. With these O2 and H2 high level, I do belived that your moisture H2O is also very high ppm.

I suspected there is some faults in your transformer.

Please get a 2nd oil test sample again and you need to do some pressure and tan-delta test on your transformer to identified the faults on your transformer.

Please see the chart

It gives the permissible Limits of Gas levels in relation to age of the transformer

In your Transformer non of the above limit is exceeded.

If Any thing Exceeded ,then we can go for analysis of fault.

Therfore your Tranformer is Healthy.

Please confirm whether the transformer is recently commissioned. In that case, there is every possibility that the trapped air in the winding and other areas During Hot Oil circulation, get released due normal vibration and collected at Bucholtz relay.

Dissolved key gas concentration limits in ppm

My main concern would be the C2H2 level. C2H2 is formed when oil sustains a temperature of 700degreesC, indicating a possible internal arcing.

Hi, Can you please tell me the limits of C2H2 levels prescribed for unused oil? Should it be 'Zero' in unused oil? Which IEC or other standard applicable for this?

We have results of 0.3 ppm in Transformer oil. The transformer is still not energised and just completed all Pre-commissioning tests. The oil is in the transformer for long 1.5 years.

hi..

No, The transformer is not recently commisioned. It has been in service for 4.5 years. and yes water content as per the testing authority was within the specified limits. i don't have the details now. But ya we inspected the JB of wires connecting bucholz relay to control and relay panel having RET521 relay and we found water ingress in it. Water was removed from the JB, and now the annunciation having "Transformer Trouble Alarm" has vanished. RET521 was showing intermittent alarm of Bucholz operated. Now, it is also not coming.

Can it was because of that..?

Thanks for the suggestions .

how about if the carbon dioxide exceeds the limits ?