Chemical reactions of of transformer oil dissolved gas analysis(DGA)
Decomposition of Oil
(1) Hydrogen, Methane, Ethane, Ethylene, Acetylene
(2) Mechanism of formation:
Scission of C-H bonds: low energy faults such as partial discharge of cold plasma (Corona)
Scission of C-C, C=C and C≡C bonds and recombination: more and more energy or higher temperature needed.
(3) Hydrogen can be generated as a result of variety of reactions Large quantities of hydrogen have been reported in some transformers that had never been energized.
Decomposition of Cellulose Insulation
(1) Mostly Carbon Monoxide and Carbon Dioxide
(2) Minor amounts of hydrocarbons and Furanic compounds
(3) Mechanism of formation:
C-O bonds in Cellulose polymer chains are thermally less stable than hydrocarbon bonds in oil.
Scission of cellulose polymer chains higher than 105℃
Complete decomposition and carbonization above 300℃
