Field screening test for used insulating oils

IN ORDER to field classify used insulating oils into “those suitable for continued service” and “those in doubtful condition,” the American Gas and Electric System about 10 years ago developed and put into use a test kit, as shown in Figure 1, for measuring neutralization value and color of oils. These test kits were put into the hands of the field insulation test crews which already had facilities for measuring oil power factor, with the request that oil from each piece of equipment be tested for neutralization number, color, and power factor and examined for visual presence of sludge.