Parameters affecting the increase in dielectric loss due to carbon black paper screens for oil-paper dielectrics-II

In the past few years it has become well established that presently available carbon black papers when used to screen the conductor or insulation of a high voltage cable increase the initial dielectric loss of that cable. Kitagawa¹ developed a formula which relates this increase to the resistivity of the carbon black paper. This formula can be expressed to a first approximation, as Δ tan δ = ω CR where C is the capacitance of the insulation and R is the series resistivity of the carbon black layer. In the work discussed last year, we showed that the resistivity formula did not provide an adequate explanation for the increase in dielectric loss due to carbon black paper.