Principal decomposition by-products generated at various abnormalities in gas-insulated transformers

It is pointed out that the application of decomposition gas analysis based on GC and IC (gas and ion chromatography) methods provides a promising practical means of predictive diagnosis of gas-insulated transformers. As the first step of developing a diagnostic method, model tests simulating important modes of abnormalities in a gas-insulated transformer were carried out. Major components characteristic of each abnormality such as SO₂ in the case of metal overheat and SO₂F₂ in the case of partial discharges were identified by the experiments. Attention is also paid to the effect of material differences, which is a major factor differentiating the gas-insulated transformer from other gas-insulated apparatus