Chemical developments in the field of cable insulation

The much discussed problem of the influence of oil oxidation on the electrical properties of impregnated paper is studied in an article by J.B. Whitehead and T. B. Jones⁽¹⁾. Accelerated oxidation tests have been made on one insulatin~ oil with oxygen introduced over the range of 0.013 to 10.4% by volume. Tests were also .made on wood pulp paper impregnated with oxidized oil. The outstanding conclusion of the work is the relative unimportance of small amounts of oxygen as a cause of change of electrical properties. It is rather that during the process of continued oxidation of oil in contact with free oxygen transitory reaction products are formed which give cause to increased liquid or gaseous ionization under electrical stress than that the oil is permanently deteriorated by the influence of small amounts of oxygen. It the contact with free oxygen is broken, small amounts of oxygen either combine or go into solution without serious impairment of the electrical properties of the oil.