Evaluation of dielectric fluids by gassing-cell tests

In recent years, the criterion of whether an oil will absorb or evolve gas when subjected to a silent or electrodeless discharge in a gassing cell, under an atmosphere of hydrogen, has been used in the selection of impregnants for oil-impregnated-paper dielectrics. The paper describes a cell which is simple in construction and operation, and which can be used over a temperature range of from ambient to 150°C. Previous work in this field is reviewed, and it is shown that the evolution or absorption of gas under gassing-cell conditions is determined by discrete reactions which are explicable in terms of classical kinetics and the chemistry of excited species.