Calculation of Multiconductor Underground Cables High-Frequency Per-Unit-Length Parameters Using Electromagnetic Modal Analysis

A new method is proposed for calculating the frequency-dependent parameters of underground cables at high frequencies where commonly used quasistationary formulations may not be valid. The method uses full-wave formulation for calculating the modal electromagnetic fields and corresponding modal voltages and currents. The proposed method can be used for any cross-sectional shape of cables. Multiconductor coaxial cables and sector-shaped cables are studied in this paper and the calculated per-unit-length parameters are compared with those obtained from commonly used formulations and other methods available in the literature.