Analysis of the propagation of traveling waves in overhead, underground, and submarine transmission lines: impact on fault location and line protection

• Grant number: 23/15636-0
• Support Opportunities: Scholarships in Brazil - Master
• Effective date (Start): September 01, 2024
• Effective date (End): April 30, 2026
• Field of knowledge: Engineering - Electrical Engineering - Power Systems
• Principal Investigator: Jose Pissolato Filho
• Grantee: Adrian Wilmer Diaz Sarmiento
• Host Institution: Faculdade de Engenharia Elétrica e de Computação (FEEC). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

The increasing demand for electrical energy poses technical and operational challenges to power utilities, especially in transmission networks. These networks must ensure the safety and reliability of energy transmission across various terrains, including urban and rural areas, and even segments crossing rivers and lakes.Innovative solutions have emerged in power transmission to address these challenges, with a particular emphasis on the use of Hybrid Transmission Lines (HTLs). These HTLs combine different lines, such as overhead, underground, and subsea, to ensure a reliable consumer energy supply while adhering to environmental and technical constraints.In this context, fault location plays a crucial role in identifying points of failure in transmission lines (TLs) after short circuits, thereby expediting the restoration of the electrical grid. Traditionally, fault location algorithms based on phasor analysis were the primary approach for this task. However, advancements in digital technology have enabled the use of algorithms based on Traveling Waves (TWs), using high-resolution voltage and current records in the MHz range. This technological evolution has revolutionized fault location and line protection strategies in real systems.This has led to the development of TW-based solutions, which have gained recognition among professionals in the electrical industry. These solutions extract information from fault transients in TLs, improving fault location methodologies and line protection. Nevertheless, research on how various HTL models affect the propagation of TWs and, consequently, fault location and line protection is an area that deserves significant exploration.This project will compare TW propagation characteristics and their impact on fault location and TL protection. The study will consider physically consistent HTL models based on J. Martí and ULM, incorporating precise formulations for line parameter calculations. These formulations, such as those by Petterson, Xue, and Pollaczek-Sunde, consider displacement current, correction for seabed admittance, and variations in soil electrical parameters with frequency. This contributes to a more accurate and comprehensive analysis of TW behavior in different fault scenarios in HTLs.Throughout the project, various fault scenarios will be simulated using the Alternative Transients Program (ATP) software, providing a clear understanding of TW propagation patterns in HTLs. It is worth noting that while simulation software like ATP has been widely used to study transient overvoltages in transmission systems, including HTLs, they often rely on assumptions that can lead to inaccurate results, especially in calculating overvoltages caused by switching events and lightning strikes.Through this master's project, the aim is to address these limitations and highlight the differences in TW propagation patterns in HTLs, with a special focus on the characteristics of ground-wave propagation, fault location, and TW-based line protection. This endeavor seeks to enhance strategies for the protection and maintenance of electrical grids, ensuring a more reliable energy supply in the face of modern challenges.