Effects of the composite structure of impregnated paper insulation on its electric properties

The effect of composite structure upon the electric properties of dielectrics has been observed and theorized upon by various people, as mentioned in the Introduction. The present paper attempts to show a quantitative expression of power-factor and dielectric loss in terms of the resistivities and specific capacities of the elements of the insulation. It also shows the electrical function of the paper in impregnated paper insulation, and cites experiments which indicate that the electric failure of such insulation is due to ionic motion in the oil; the obvious deduction being that the voltage rating of cables should depend upon the degree to which ionic motion in the oil can be restrained.