Analysis of Overvoltages in Power Systems Due to Lightning Strikes: On the Effects of the Line Modeling Approach and Frequency-Dependent Soil Properties

Author(s)

Garbelim Pascoalato, Tain A. Fernanda ; Manzi de Azevedo, Walter Luiz ; Justo de Araujo, Anderson Rircardo ; Martins-Britto, Amauri Gutierrez ; Kurokawa, Sergio ; Filho, Jose Pissolato

• Document type: Journal article
• Source: 2024 59TH INTERNATIONAL UNIVERSITIES POWER ENGINEERING CONFERENCE, UPEC; v. N/A, p. 6-pg., 2024-01-01.

Abstract

This article presents a comparison considering a more conservative modeling approach (classical) and a more realistic modeling approach (enhanced) for the transient analysis of the overvoltages resulting from lightning strikes in a power system. The classical modeling approach considers JMarti's line model where the ground-return impedance is calculated with Carson's approach assuming frequency-constant (FC) soil conductivity and neglecting the relative permittivity of the soil and the ground-return admittance. For the improved modeling approach, the universal line model (ULM) is used as a line model, incorporating the frequency-dependent (FD) soil parameters and the ground-return impedance and admittance calculated with Nakagawa's equations. This study considers the main components of the power system, such as transmission lines and tower structures with their tower-footing grounding systems. For this analysis, a 138-kV transmission line is subjected to a lightning strike, assuming a homogeneous ground with five different values of soil resistivity (300, 600, 1,000, 2,000, and 4,000 Omega.m). The simulation results demonstrate a significant difference in the overvoltage waveforms obtained with the enhanced modeling approach compared to the classical modeling approach, mainly in their peak values. These differences in the overvoltage waveforms are more pronounced for high-resistivity soils. The correct computation of the lightning overvoltage is crucial for designing the adequate insulation level of several components for OHTL and substations, providing safety to operating personnel as well as people in the vicinity of these installations, and computing the backflashover rate. (AU)

• FAPESP's process: 22/09182-3 - Modeling of multiphase transmission lines considering frequency-dependent soil parameters: transient analysis via ATP software
• Grantee: Tainá Fernanda Garbelim Pascoalato
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 20/10141-4 - Influence of the soil electromagnetic characteristics in the transient responses in electric transmission lines
• Grantee: Tainá Fernanda Garbelim Pascoalato
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 21/11258-5 - Engineering Research Center for the Aerial Mobility of the Future (ERC-AMF)
• Grantee: Domingos Alves Rade
• Support Opportunities: Research Grants - Research Centers in Engineering Program
• FAPESP's process: 19/01396-1 - Modelling conventional and tall transmission towers directly in time domain for electromagnetic transient analysis
• Grantee: Anderson Ricardo Justo de Araújo
• Support Opportunities: Scholarships in Brazil - Post-Doctoral