Accurate Impedance Calculation for Underground and Submarine Power Cables using MoM-SO and a Multilayer Ground Model

TL;DR

This paper presents an enhanced MoM-SO method with a multilayer ground model for precise impedance calculation of underground and submarine power cables, significantly improving accuracy and speed over traditional methods.

Contribution

It introduces a multilayer ground model for MoM-SO, enabling accurate impedance prediction in complex layered environments, outperforming analytic formulas and matching FEM accuracy with much higher efficiency.

Findings

The method achieves FEM-like accuracy in impedance calculations.

It is over 1000 times faster than FEM for complex multilayer scenarios.

Calculates impedance of submarine cables within 0.10 seconds per frequency.

Abstract

An accurate knowledge of the per-unit length impedance of power cables is necessary to correctly predict electromagnetic transients in power systems. In particular, skin, proximity, and ground return effects must be properly estimated. In many applications, the medium that surrounds the cable is not uniform and can consist of multiple layers of different conductivity, such as dry and wet soil, water, or air. We introduce a multilayer ground model for the recently-proposed MoM-SO method, suitable to accurately predict ground return effects in such scenarios. The proposed technique precisely accounts for skin, proximity, ground and tunnel effects, and is applicable to a variety of cable configurations, including underground and submarine cables. Numerical results show that the proposed method is more accurate than analytic formulas typically employed for transient analyses, and delivers an accuracy comparable to the finite element method (FEM). With respect to FEM, however, MoM-SO is over 1000 times faster, and can calculate the impedance of a submarine cable inside a three-layer medium in 0.10~s per frequency point.