Effects of Multiple Semiconducting Screens on Line Parameters and Wave Properties of Underground Cable

Along with the geometric and electromagnetic properties, incorporation of multiple semiconducting screens in an underground (UG) power cable influences the primary line parameters as well as wave properties of the cable. The impacts of multiple semiconducting screens in UG cable structure compared to the cable with single and without semiconducting screen have been reported in this paper. The effective impedance of conductor-semiconductor assembly in cable structure is determined based on the electromagnetic theory of tubular conductor. Further, the complete impedance matrix of the UG cable with multiple semiconducting screens is determined in both mesh and phase domain and reported in this paper. The expressions of the impedances of UG cable with multiple semiconducting screens as obtained using the electromagnetic approach also have been reproduced using the conventional loop current method to justify the robustness and accuracy of the adopted approach. Comparative analyses of various line parameters and wave properties between UG cables with multiple, single and without semiconducting screens have been carried out by varying the frequency as well as semiconducting screen properties. Such analyses indicate that the inclusion of multiple semiconducting screens can lead to the improvement in wave properties of UG cable in high frequency zone.