Advanced Numerical Computation of Electromagnetic Field of Power Lines and Substations

Abstract

In this doctoral thesis, an improved quasi-static electromagnetic model for calculating the low-frequency electromagnetic field of power lines and facilities has been developed. The basis of the developed model is the application of the finite element technique to the integral formulation of the problem in the frequency domain. A thin-wire approximation of cylindrical conductor segments is used. To describe the passive conductive parts of electrical facilities and overhead line poles, spatial 2D subparametric finite elements with an arbitrary number of nodes have been developed to describe the distribution of the areal charge density per individual finite element. In the numerical model, it is assumed that the cylindrical segments of active and passive conductors have a constant line charge density, which is mathematically located in the conductor axis. The singularity problem that occurs with double integration by spatial 2D finite elements has been solved by developing an advanced algorithm for double numerical integration based on Gaussian numerical integration. An algorithm for segmenting conductors and overhead line poles based on basic input data on their geometry has also been developed. The phase conductors and protective wires of overhead power lines are approximated by a set of straight cylindrical segments, which sufficiently accurately approximate the shape of a catenary. The influence of passive conductive parts of power lines and facilities on the distribution of electric field strength and magnetic induction is also taken into account. The influence of passive conductive parts on the distribution of magnetic induction is calculated using a set of real and equivalent current contours. The accuracy of the developed quasi-static electromagnetic model for calculating the low-frequency electromagnetic field of power lines and facilities is confirmed by comparing the calculation results with the results obtained using other software packages, with analytical solutions available in the literature, and with measurement results.

Tonći Modrić

Associate Professor | Department of Electrical Intallations and Systems

Researcher and Full Professor at the Faculty of Electrical Engineering, Mechanical Engineering, and Naval Architecture in Split. His research focus is numerical modeling and calculation of the electric and magnetic fields in power systems and transmission lines, with an emphasis on the development of advanced models for interpreting geoelectrical ground survey data. Additionally, he is involved in the analysis of electromagnetic transients in systems with a high share of renewable energy sources, using finite element techniques.