Maximum TDCG
Maximum TDCG
(OP)
Hello,
I have a transformer with stable dissolved gasses but I was wondering..
What is the maximum acceptable value of total combustible dissolved gasses (ppm) before degassing or oil change is necessary?
I saw in IEEE Std C57.104-1991 a couple of tables where they mainly talk about gas increasing rates (ppm/day). Many articles and people told me that the rates are indeed the most important thing to monitor, but what about the absolute TDCG value? Should the transformer be degassed when TDCG are over 4000ppm? 5000?
I have a transformer with stable dissolved gasses but I was wondering..
What is the maximum acceptable value of total combustible dissolved gasses (ppm) before degassing or oil change is necessary?
I saw in IEEE Std C57.104-1991 a couple of tables where they mainly talk about gas increasing rates (ppm/day). Many articles and people told me that the rates are indeed the most important thing to monitor, but what about the absolute TDCG value? Should the transformer be degassed when TDCG are over 4000ppm? 5000?






RE: Maximum TDCG
The list of gases generated during oil degradation are: hydrogen (H2), methane (CH4), ethane (C2 H6), ethylene (C2 H4), acetylene (C2 H2), carbon monoxide (CO), and oxygen (O2).
The enclose link may provide you with general direction for DSG concentration limits.
See table 4 on page 38. http://
RE: Maximum TDCG
RE: Maximum TDCG
This is exactly what I thought. Just wanted to confirm there was no point where the dissolved combustible gasses could become dangerous (explosion, fire, etc), even if their concentration is stable.
We did processed oil from several other transformers in the past because of their poor quality, but never had to do it only because of the gasses.
Thank you both for your answers!