Effect of Organic Additives, Gas Phase, Stress, and Temperature on the Gassing Characteristics of Insulating Liquids

This paper describes the effects of adding small concentrations of organic additives (anthraquinone, benzophenone, and diphenyl) to transformer oil on its gassing characteristics under different gas phases (H2, N2, O2, and air), different stresses and different temperatures. The results show that there exists an optimum concentration for each of the additives used. The optimum concentrations were found to be independent of the gas phase used. Also, for a given test liquid the results indicate the presence of an optimum stress for both gas-evolving and gas-absorbing oils. The results obtained are explained in terms of the free radical mechanism for gassing of oils under electrical stress.