Numerical model for induced voltages calculation along double circuit overhead transmission lines

Abstract

This paper presents a simple and reliable algorithm for harmonic analysis of both current and voltage conditions along two-system overhead lines. The developed numerical model for the analysis of induced voltages along two-system overhead lines is based on the finite element technique (FET). The essence of the finite element technique is to reduce the problem of solving a complicated system to the problem of solving a subsystem, for which we can easily define a local system of equations based on a mathematical model. In order to calculate the distribution of short-circuit current along the observed two-system overhead lines, it is necessary to divide the entire transmission line into as many finite elements as there are spans. It is also necessary to represent each tower earthing switch as a separate finite element. The hydroelectric power plant with its associated generators and the incident network are also represented as separate finite elements with associated parameters. The safety of the contractor working on the disconnected triplex of the two-system line directly depends on the amount of induced voltages at the work site. As the worst case scenario from the point of view of induced voltages, we considered the case of a single-pole short circuit on the active triplex of the transmission line, where the highest possible current value was taken into account. During this time, the disconnected or passive triplex was grounded on both sides. The induced voltages were analyzed in the case of a grounded work site and the two adjacent poles along the entire dual-system line.

Ivica Jurić-Grgić

Full Professor | Department of Theoretical Electrical Engineering and Modelling

Researcher and full professor at the Faculty of Electrical Engineering, Mechanical Engineering, and Naval Architecture in Split. His research focuses on numerical modeling of electromagnetic transients in power systems, with particular emphasis on the development of advanced numerical methods for analyzing electromagnetic transients in multi-conductor transmission lines. His work includes the application of finite element techniques for transient stability analysis of power systems, as well as the enhancement of models for harmonic and transient analysis of grounding systems.

Rino Lucić

Full Professor

Dr. sc. Rino Lucić is a retired professor from the Faculty of Electrical Engineering, Mechanical Engineering, and Naval Architecture in Split. Throughout his career, he taught courses at all study levels and actively participated in the realization of numerous scientific-research projects. As an author or co-author, he has published 41 scientific papers and 16 professional articles, with research interests spanning numerical modeling, transmission lines, finite element method, and power system transient analysis.