Electric field determination of polymeric dc power cable in the presence of space charge

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Description/Abstract

Space charge in polymeric power cables has been previously measured by the pulsed electroacoustic (PEA) technique and its influence on electric field distribution has been estimated assuming that the conductivity is independent of electric field. In this paper we proposed a method of determining electric field distribution considering the influence of the effect of electric field on the conductivity. The cable insulation is divided into thin layers with different conductivities and space charge present in the each layer is viewed as the consequence caused by difference in conductivity. Based on the hopping conduction mechanisms, it is possible to compute electric field distribution across the cable insulation. Compared with the electric field distribution without considering change in conductivity, the new proposed method shows reduction at the maximum electric field. However, the position of the maximum electric field shifts depending on space charge distribution.