Electrical Characteristics of Oil-Impregnated Paper as Insulation for HV DC Cables

In dc cables the resistivity of the insulation is a very important parameter, as it determines the stress distribution and the power losses in the insulation. This paper gives the results of several tests on plane capacitors, from which the steady-state resistivity of four different kinds of paper and impregnants appear to be almost identical from this point of view. The transient behavior of one of the dielectrics is also shown, giving the current density as a function of time after the application of a direct voltage, for different temperatures and stresses.