Gas chromatography analysis of dissolved gases in insulating oil can analyze the composition and content of dissolved gases in transformer oil to determine potential failures in transformers and other oil-filled electrical equipment.
One is the gas generated by the internal fault of the transformer
The dissolved gas of new insulating oil usually contains about 70% N2, about 30% O2 and about 0.3% CO2 gas. It does not contain four gases: C1 and C2 (CH4, C2H6, C2H4 and C2H2, usually called For low molecular hydrocarbons such as C1 and C2). However, after oil treatment, due to dead spots in the heating system of some oil treatment equipment, trace amounts of ethylene or even trace amounts of acetylene sometimes appear. For the normal operation of transformer oil, due to the slow decomposition and oxidation of oil and insulating materials, a small amount of CO2, CO and trace amounts of low-molecular hydrocarbons will be produced, but the amount is far less than the amount of gas generated by a fault.
When a fault occurs inside the transformer, mainly due to thermal failure (current effect) and electrical failure (voltage effect) in the insulating oil and solid insulating materials, CO2, CO, H2 and low molecular hydrocarbon gases in the oil will increase significantly. . However, during the initial stages of failure, the growth of these gases is not sufficient to cause the operation of the gas relay. At this time, by analyzing these gases dissolved in the oil and making correct judgment, the internal fault of the transformer can be determined as early as possible.
