Influence of Absorbed Water and Temperature on Tan Delta and Dielectric Constant of Oil-Impregnated Paper Insulation

Tan ¿ and dielectric constant at several temperatures and stresses of an oil-impregnated 0.95 density paper, suitable for use in extra-high-voltage cables, are related quantitatively to water content m from 0.08 to 4.82%. At 100 C (degrees centigrade), 100 tan ¿=0.24+1.44 m2, tribution of hydrogen and hydroxyl ions from the water. At 22 C, small amounts of water have a linear effect on tan ¿, a relation believed to result from the water plasticizing the cellulose. In the range 22 to 100 C, k¿=3.8+0.41 m.