A New Method of Investigating Cable Deterioration and Its Application to Service Aged Cable

Investigation of the radial variation in electrical and chemical characteristics of cable insulation between conductor and sheath is suggested as a valuable means for throwing new light on cable´deterioration in service. An apparatus is described for the rapid accurate measurement of power factor of individual paper tapes taken from cable. A method is given for determining the total oxidation products in the oil from the paper tapes, layer by layer, from sheath to conductor. The results obtained by applying these methods to several types of service aged cable are reported, together with the indications which they give of the relative importance of ionization and oxidation as aging factors.