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?