A Comparison of Frequency-Dependent Soil Models: Electromagnetic Transient Analysis of Overhead Transmission Lines Using Modal Decomposition

This article investigates the influence of four causal frequency-dependent (FD) soil models and their impact on responses a multiphase overhead transmission line (OHTL) with ground wires, generated by lightning strike. The FD proposed Longmire-Smith (LS), Messier (M), Portela (P) Alípio-Visacro (AV) are considered. ground-return impedance admittance matrices computed Nagakawa approach for both frequency-constant models. frequency-domain modal voltages time-domain transient assessed in this work. Modal decomposition technique is used to study attenuation constant, propagation velocity each mode. Simulations carried out frequency range 100 Hz 10 MHz, OHTLs lengths 1 km, soils 700 4000 Ω·m. Simulation results demonstrated that model has resulted more significant variation admittance, constant which pronounced variation, especially at high frequencies, seen. On other hand, (LS) (M) have produced similar time domains. Additionally, intermediate responses, being recommended CIGRÈ WG C4.33. Time-domain induced voltage waveforms obtained shown differences, peak values, high-resistive soil. demonstrates importance considering assess adequately, when soils.