Transformer oil preservation methods

IN ALL COMMONLY USED SYSTEMS of oil preservation for power transformers, the oil surface is exposed to a gas, either air as with a conservator system or nitrogen if the automatic-gas-seal system is used. Where a gas and a liquid are in such contact, some of the gas dissolves into the liquid, the quantity depending upon the kind of gas and liquid and their temperature and pressure. The solubility of nitrogen in transformer oil increases linearly with both pressure and temperature over the relatively narrow ranges encountered in transformer operation.