Investigation of surge characteristics of vertically arranged co-axial cable

Abstract

In EMTP, it is very hard to simulate a vertically arranged cable, since its surge impedance gradually changes with the distance from the ground to a top point. In the past, some researches about surge impedances and responses of vertical conductor (for example transmission tower, concrete pole and so on.) have been carried out, these researches are being continued now. However, there is no model of vertical co-axial cable in EMTP. In order to analyze surge voltage arisen on the electrical system, approach of method for treating this model in EMTP is required. In this paper, experiments of surge impedance and response on vertical cable, method of treating for vertical co-axial cable in EMTP and accuracy confirmed as compared result of this model with analysis result of VSTL Rev. (Virtual Surge Test Lab. rev.) which is constructed under FDTD (Finite Difference Time Domain) method, are reported.