transformer dga analysis,

[steveng]

this is the test results on 2 oil filled xfmrs, #1 is 750kva and #2 is 500kva

this is a weidmann report, 750 kva 12.470/480 deltawye, 315 gallon oil
age 31 yrs, anyone have experience on dga or can give some intreptative opinions?
thanks

#1 #2
oil temp 22 25
hydrogen 70 18
methane 137 51
ethane 292 107
ethylene 108 15
acetylene 3 0
carbon monoxide 569 716
carbon dioxide 4375 8709
nitrogen 63674 56255
oxygen 373 1282
total gas 69601 67153
total comb gas 1179 907
moisture in oil 5 8
interfacial tension 41.2 38.6
acid number 0.02 0.025
visual exam clr & sprk clr&sprk
sediment trace nd
dielectric breakdown 56 50

 

[quogueelectric]

You are in so much trouble I cant begin to explain.

 

[steveng]

You are in so much trouble I cant begin to explain.

thanks quoguee, thats was helpful

 

[chaterpilar]

Your transformer needs blood transfusion...Steve.

 

[zog]

this is the test results on 2 oil filled xfmrs, #1 is 750kva and #2 is 500kva

this is a weidmann report, 750 kva 12.470/480 deltawye, 315 gallon oil
age 31 yrs, anyone have experience on dga or can give some intreptative opinions?
thanks

#1 #2
oil temp 22 25
hydrogen 70 18
methane 137 51
ethane 292 107
ethylene 108 15
acetylene 3 0
carbon monoxide 569 716
carbon dioxide 4375 8709
nitrogen 63674 56255
oxygen 373 1282
total gas 69601 67153
total comb gas 1179 907
moisture in oil 5 8
interfacial tension 41.2 38.6
acid number 0.02 0.025
visual exam clr & sprk clr&sprk
sediment trace nd
dielectric breakdown 56 50

Whoever drew the sample should be interpreting the results for you, there are several methods (Ket gas, Rogers ratios, dourenburg ratios, triangle method, and the new IEEE C57 method to name a few) to use and previous samples data need to be looked at also. I will tell you what I can from this "snapshot" of info you posted.

Transformer#1 - Has obviously seen some severe overheating based on the high methane and ethane gas levels, these gasses are produced from LOCALIZED overheating such as a bad tap changer connection or similar. Your TCG is 1119 which indicates decompostion. Have this unit tested by someone who knows what they are doing, be careful here, buying a new transformer or repairing this one hangs in the balance.

Transformer #2 - Pretty much the same story as #1 but not as severe, methane is within levels. Ethane and TDG are both concerns here.

 

[steveng]

Whoever drew the sample should be interpreting the results for you, there are several methods (Ket gas, Rogers ratios, dourenburg ratios, triangle method, and the new IEEE C57 method to name a few) to use and previous samples data need to be looked at also. I will tell you what I can from this "snapshot" of info you posted.

Transformer#1 - Has obviously seen some severe overheating based on the high methane and ethane gas levels, these gasses are produced from LOCALIZED overheating such as a bad tap changer connection or similar. Your TCG is 1119 which indicates decompostion. Have this unit tested by someone who knows what they are doing, be careful here, buying a new transformer or repairing this one hangs in the balance.

Transformer #2 - Pretty much the same story as #1 but not as severe, methane is within levels. Ethane and TDG are both concerns here.

Thanks Zog, I appreciate your explanation and advice. the reason i ask for interpretations is to gain more knowlege and understanding, the testing co will have the discretion on oil processing and we will use their interpretation
of the results. my purpose is twofold, to protect this facility and to learn as
as much as possible on this equipment.

these are scheduled to be retested this month.
we have replaced 1 and processed 2. we have 8 total at our facility.

these test reports used the ieee(C57.104) method

i will post a follow up result.

thanks again Zog,
steve

 

[zog]

Thanks Zog, I appreciate your explanation and advice. the reason i ask for interpretations is to gain more knowlege and understanding, the testing co will have the discretion on oil processing and we will use their interpretation
of the results. my purpose is twofold, to protect this facility and to learn as
as much as possible on this equipment.

these are scheduled to be retested this month.
we have replaced 1 and processed 2. we have 8 total at our facility.

these test reports used the ieee(C57.104) method

i will post a follow up result.

thanks again Zog,
steve

The samples were drawn per IEEE method, not the report. I was refering to the new IEEE C57 method for the interpration of DGA results, and that hasnt been done yet.

I think you took the perfect actions by replacing unit #1 and processing #2, curious to see what the results are for #2 after processing. Could you post the electrical test results from #2?

You using Shermco?

 

[steveng]

The samples were drawn per IEEE method, not the report. I was refering to the new IEEE C57 method for the interpration of DGA results, and that hasnt been done yet.

I think you took the perfect actions by replacing unit #1 and processing #2, curious to see what the results are for #2 after processing. Could you post the electrical test results from #2?

You using Shermco?

Zog, we use ecp tech, and when i get the results, i will post up.
thanks for your help,

Do you do this kind of work every day? its challenging work, you have to sharp to stay alive, right

 

[zog]

Zog, we use ecp tech, and when i get the results, i will post up.
thanks for your help,

Do you do this kind of work every day? its challenging work, you have to sharp to stay alive, right

Well I did for the last 15 years, now I have shifted gears and am in more of a supervisory role for a new company that does more equipment replacement and custom jobs than service work, but I still do go out and get dirty in the field every once in a while. But I have done hundreds of DGA samples and analysis in the past.