Deeper Insight into the Relationship between Experimental Expressions of Conductivity and DC Electric field in cables

This paper aims at a deeper insight into analytical relationships between experimental expressions of electrical conductivity and electric field in DC cables. An analytical relationship was found in a previous paper focusing on one model of electrical conductivity only. Here the analysis is broadened to another more complex model used sometimes in the technicalscientific literature, and the derivation of the analytical relationship between the experimental conductivity expression and the electric field is carried out parametrically. A case study for DC-XLPE cable insulation is shown for the sake of illustration. The results agree with the literature values. While the temperature coefficient of conductivity a is weakly dependent on temperature, the stress coefficient of conductivity b is strongly dependent on electric field, especially for typical fields of HVDC cables.