High voltage underground cable insulation

J.B. Whitehead and Mauritz⁽¹⁾ study the changes in insulating oils under the influence of accelerated oxidation. For a typical high grade insulating oil, linear relations are found over a wide range between the amount of oxygen chemically absorbed and time, acid number, saponfication number, and carbon dioxide evolved. Similar linear relations have been found between the oxygen absorbed, power factor, and long-time d-c conductivity as measured at 40°C. These correlations might provide a basis for estimating the relative oxidation stabilities of different oils.