Error Images for Estimating the Accuracy of Ground-Return Impedance Models

A graphical method based on error images to validate the accuracy of two of the most important recently published ground-return impedance models of underground power cables is described in this letter.

I. Introduction

The analysis of electromagnetic transients in an underground cable installation requires the calculation of ground-return impedances [1]. The resistance and reactance ground values depend on media parameters and physical variables, usually observed along frequency. However, there are circumstances when the is required to be evaluated for different configurations or parameters, for a given conductivity soil. In these cases, a graphical validation of methods for calculation of at a broad range of applications can be very useful. Two of the most recent models proposed to evaluate are given by Theodoulidis [2] and Noda [3] applied to solve the Pollaczek integral [1].